Particularly strong C-H interactions between benzene andall-cis123456-hexafluorocyclohexane
Rodrigo A Cormanichab Neil S Keddiea Roberto Rittnerb David OrsquoHagana andMichael Buumlhla
aEastChem School of Chemistry University of St Andrews North Haugh St Andrews Fife KY16 9ST UK
bChemistry Institute State University of Campinas PO Box 6154 13083-970 Campinas SP Brazil
E-mail mb105st-andrewsacuk
Electronic Supplementary Material (ESI) for Physical Chemistry Chemical PhysicsThis journal is copy the Owner Societies 2015
S2
Computational details
Geometries were fully optimized at the B3LYPdef2-TZVP B3LYP-D3def2-TZVP and
MP2aug-cc-pVDZ levels and magnetic shieldings evaluated at the BHandH6-311+G(2dp)
level for each geometry by using the Gaussian 09 Revision D01 program1
DFT calculations
employed a fine integration grid (ie 75 radial shells with 302 angular points per shell) At
that level the B3LYP optimised structure displayed a small imaginary frequency (3i cm-1)
which vanished upon reoptimisation with tighter optimisation thresholds and an ultrafine
integration grid (ie 99 radial shells with 590 angular points per shell) Optimisations for
the complexes with benzene were performed including correction for basis-set
superposition error (BSSE) by way of the Counterpoise method2 1H magnetic shieldings
were converted into relative chemical shifts using the 1H magnetic shielding in TMS
computed at the same respective levels The energies were converted into enthalpies and
Gibbs free energies using standard thermodynamic corrections from the frequency
calculations for each levelComplete basis set calculations were performed using the
extrapolation scheme by Helgaker and coworkers3 This procedure is based on calculations
with Dunnings correlation-consistent basis sets4 with increasing cardinal numbers and
involves separate extrapolation for HF and the second-order perturbation correction E(2)
using inverse exponential and cubic fits respectively We did this for the calculated
absolute energies (not corrected for BSSE) from MP2 (and SCS-MP2)aug-cc-pVxZ single
points (x = D T Q) on MP2aug-cc-pVDZ optimised geometries (HF single points up to aug-
cc-pV5Z basis) Extrapolations of energies obtained including Counterpoise corrections or
using an inverse quadratic fit for E(2) afforded very similar CBS limits for each system all
within ca plusmn04 kcalmol of the standard fit (slightly larger variations up to plusmn06 kcalmol
were obtained when both BSSE corrections and an inverse quadratic fit were used see
Tables S2-S5 for details and results) When complexation energies rather than absolute
energies were extrapolated similar standard deviations were obtained from the fitting
procedure (plusmn04 kcalmol Table S3) Because these fits of complexation energies do not
1 Gaussian 09 Revision D01 M J Frisch G W Trucks H B Schlegel G E Scuseria M A Robb J R CheesemanG Scalmani V Barone B Mennucci G A Petersson H Nakatsuji M Caricato X Li H P Hratchian A F IzmaylovJ Bloino G Zheng J L Sonnenberg M Hada M Ehara K Toyota R Fukuda J Hasegawa M Ishida T NakajimaY Honda O Kitao H Nakai T Vreven J A Montgomery Jr J E Peralta F Ogliaro M Bearpark J J Heyd EBrothers K N Kudin V N Staroverov R Kobayashi J Normand K Raghavachari A Rendell J C Burant S SIyengar J Tomasi M Cossi N Rega J M Millam M Klene J E Knox J B Cross V Bakken C Adamo J JaramilloR Gomperts R E Stratmann O Yazyev A J Austin R Cammi C Pomelli J W Ochterski R L Martin KMorokuma V G Zakrzewski G A Voth P Salvador J J Dannenberg S Dapprich A D Daniels Ouml Farkas J BForesman J V Ortiz J Cioslowski and D J Fox Gaussian Inc Wallingford CT 2009
2 (a) S F Boys F Bernardi Mol Phys 1970 19 553 (b) S Simon M Duran J J Dannenberg J Chem Phys 1996
105 11024
3 T Helgaker W Klopper H Koch J Noga J Chem Phys 1997 106 9639
4 (a) T H Dunning Jr J Chem Phys 1989 90 1007 (b) R A Kendall T H Dunning Jr R J Harrison J Chem
Phys 1992 96 6796 (c) D E Woon T H Dunning Jr J Chem Phys 1993 98 1358 (d) K A Peterson D E Woon
T H Dunning Jr J Chem Phys 1994 100 7410 (e) A K Wilson T van Mourik T H Dunning Jr J Mol Struct
(Theochem) 1996 388 339
S3
show the proper convergence behavior of those using absolute energies (Figure S1) we
used only the latter (for which the basis sets were designed) We report the standard fit
results according to Helgaker et al3 (ie without Counterpoise correction and using an
inverse cubic fit) and use the plusmn04 kcalmol variation as a conservative error estimate
The MP2aug-cc-pVDZ total electron densitiy was evaluated for the geometry of 3C6H6
optimised at that level (optimisation done including Counterpoise correction) and was
used to run QTAIM (quantum theory of atoms in molecules)5 and NCI (non-covalent
interactions) calculations6 using the AIMALL7 and NCIPLOT 30 programs6 respectively
Experimental Details
All cis-123456-hexafluorocyclohexane was synthesised in 12-steps as a colourless solid (cf
reference 4 of the main paper) mp 206ndash208 ˚C (CH2Cl2)1H NMR (700 MHz CD2Cl2) δH 540-
523 (3H m Heq) and 461-446 (2H m Hax)13C NMR (125 MHz CD2Cl2) δC 895-843 (6C m)
Melting points were determined on a Reichert hot stage microscope and are uncorrected
1H NMR measurements were carried out on a Bruker Avance III 700 spectrometer equipped
with a TXI probe operating at 700 MHz using the deuterated solvent as the reference for
internal deuterium lock 13C NMR measurements were carried out on a Bruker Avance III HD
spectrometer equipped with a BBFO probe operating at 125 MHz with broadband 1H
decoupling using the deuterated solvent as the reference for internal deuterium lock The
chemical shift data are given as δ in units of parts per million (ppm) relative to
tetramethylsilane (TMS) where δ (TMS) = 000 ppm Each spectrum was referenced to the
residual solvent signal The solutions for NMR analysis were prepared by mixing
hexafluorocyclohexane with d2-dichloromethane (CD2Cl2) or d6-benzene (C6D6) and sonicating
the mixture for 30 s Any remaining solids were allowed to settle before the solution was
decanted to a 5 mm NMR tube The final concentration of the solutions was estimated to be le
1 mgmL-1
5 R F W Bader Atoms in Molecules A Quantum Theory Clarendon Oxford 1990
6 E Johnson S Keinan P Mori-Saacutenchez J Contreras-Garciacutea A Cohen W Yang J Am Chem Soc 2010 132 6498
7 AIMAll (Version 141123) T A Keith TK Gristmill Software Overland Park KS USA 2013 (aimtkgristmillcom)
S4
Table S1 Distances between the benzene ring and the cyclohexane axial hydrogen atoms C-
H (angstroms) and binding energies (kcal mol-1) for raw potential energies (E)
enthalpies (H) and Gibbs free energies (G) for compounds 3-53 4 5
C-H 3105 Aring 3442 Aring ---
B3LYP E -212 -075 ---
H -130 -004 ---
G +612 +698 ---
C-H 2694 Aring 2786 Aring 2834 Aring
B3LYP-D3 E -706 -484 -340
H -680 -471 -263
G +463 +592 +527
C-H 2710 Aring 2805 Aring 2868 Aring
MP2[a] E -695 -488 -317
H -613 -417 -240
G +128 +285 +550[a]
MP2 thermal corrections were obtained from B3LYP-D3def2-TZVP frequencies calculated fromB3LYP-D3def2-TZVP equilibrium geometry
S5
Table S2 Compounds 3 and 4 binding energies (kcal mol-1) and C-H distances (angstroms)obtained at different levels
[b]Single point energy calculations on MP2aug-cc-pVDZ optimised geometries
[c]MP2 and SCS-MP2 levels used thermal corrections obtained from B3LYP-D3def2-TZVP frequency
calculations on B3LYP-D3def2-TZVP geometries
S6
Table S3 Compounds 3 and 4 binding energies (kcal mol-1) obtained with aug-cc-pVXZ basissets (X = 2 3 and 4 X = 5 for the HF method was also used) Complete basis set (CBS) energieswere computed from the binding energies in kcal mol-1
Compound 3 Compound 4
HFCBS[a]
-013 +- 0009899 +141+- +- 0002333
E(2)
aug-cc-pVDZ -985 -887E
(2)aug-cc-pVTZ -875 -799
E(2)
aug-cc-pVQZ -781 -714
E(2)
CBS[b]
-780 +-03852 -716 +-03643E
(2)CBS
[c]-736 +- 03808 -679 +- 03719
MP2CBS[d]
-793 +-0395099 -575 +-0366633
E(2)
(SCS)aug-cc-pVDZ -828 -746E
(2)(SCS)aug-cc-pVTZ -724 -659
E(2)
(SCS)aug-cc-pVQZ -623 -569
E(2)
(SCS)CBS[b]
-626 +- 04336 -573 +- 03943E
(2)(SCS)CBS
[c]-581 +- 04432 -535 +- 04086
SCS-MP2CBS[e]
-639 +- 0443499 -432 +- 0396633SCS-MP2CBS
[f]-594 +- 0453099 -394 +- 0410933
[a]Using the equation E(HF) = a + be
-cXwith X = 2 3 4 and 5 from HF=aug-cc-pVXZ energies in Table X
[b]Using the equation E
(2)= a + bX
-3
[c]Using the equation E
(2)= a + bX
-2
[d]MP2CBS = HFCBS + E
(2)CBS
[e]SCS-MP2CBS = HFCBS + E
(2)(SCS)CBS for the equation E
(2)= a + bX
-3
[f]SCS-MP2CBS = HFCBS + E
(2)(SCS)CBS for the equation E
(2)= a + bX
-2
S7
Table S4 Absolute energies (atomic units) for each monomer and complexes with benzene computed by using aug-cc-pVXZ basis sets (X = 2 3 and 4 and X= 5 for the HF method) Complete basis set (CBS) extrapolated energies obtained from such energies and the fitting errors are indicated for each case
Table S5 Binding energies (kcal mol-1) obtained from CBS absolute energies showed in TableS4 for compounds 3 and 4
3 4
HFCBS -013 +141
HFCBS (BSSE) -044 +089
E(2)CBS[a] -781 -714
E(2)CBS[b] -737 -678
E(2)CBS[a] (BSSE) -749 -690
E(2)CBS[b] (BSSE) -806 -732
MP2CBS[c] -793 -575
MP2CBS[d] -750 -537
MP2CBS[c] (BSSE) -762 -549
MP2CBS[d] (BSSE) -850 -643
E(2)(SCS)CBS[a] -626 -574
E(2) (SCS)CBS[b] -582 -535
SCS-MP2CBS[c] -639 -433
SCS-MP2CBS[d] -595 -394
[a]E
(2)= a + bX
-3from Table S4
[b]E
(2)= a + bX
-2from Table S4
[c]MP2CBS and SCS-MP2 = HFCBS + E
(2)CBS E
(2)CBS value used was that obtained from equation E
(2)= a + bX
-3
[d]MP2CBS and SCS-MP2 = HFCBS + E
(2)CBS E
(2)CBS value used was that obtained from equation E
(2)= a + bX
-2
S9
Plots for Relative Energies (Table S3)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Plots for Absolute Energies (Table S4)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Figure S1 Plots of equations E (2)CBS = a + bX-3 and E (2)CBS = a + bX-2 for X = 2 3 and 4 (basis set
aug-cc-pVXZ) E (2)CBS values used from Table S3 (relative energies) and Table S4 (absolute
energies)
S10
Table S6 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
Table S7 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYP-D3def2-TZVP optimised geometries with BSSE corrections included
Table S9 Calculated 1H isotropic shielding tensors for ghostrdquo atoms obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
3C6H6 4C6H6
Hax 118 088
Heq (down) 036 034
Heq (up) --- 028
S14
a) b) c)
Figure S2 Results from topological analysis of the total electron density of 3C6H6 (MP2aug-cc-
pVDZMP2aug-cc-pVDZ level) a) Molecular graph from Atoms-in-Molecules analysis green
bond critical points (BCPs) red ring critical points blue cage critical point Key properties of the
three BCPs connecting 3 to C6H6 = 0007 2 = +0020 ellipticity=+0393 K = -00006 V =
00038 G = +00044 (all in au) b) NCI isosurfaces for 3C6H6 obtained with reduced density
gradient (RDG) = 05 and blue-green-red color scale ranging from minus002 au lt sign(λ2)ρ(r) lt +002
au c) Graph of RDG versus sign(λ2)ρ for 3C6H6 The regions between the axial H atoms of 3 and
the closest C atoms of benzene are included in the downward peak at negative sign(λ2)ρ
indicating weakly attractive interactions
S15
Figure S3 Experimental 1H NMR spectra (700 MHz) of 3 in CD2Cl2 (bottom) and C6D6 (top)
illustrating the upfield shifts of the signals on going into the aromatic solvent An impurity of
diethyl ether was present in the NMR samples
Figure S4 Experimental 1H 1D gradient selective TOCSY NMR spectra (700 MHz) of 3 in CD2Cl2
(top) irradiated on the Hax signal at 459 ppm and 1H NMR of 3 in CD2Cl2 (bottom) illustrating the
overlap of the Heq protons of 3 with the residual CD2Cl2 solvent signal
S2
Computational details
Geometries were fully optimized at the B3LYPdef2-TZVP B3LYP-D3def2-TZVP and
MP2aug-cc-pVDZ levels and magnetic shieldings evaluated at the BHandH6-311+G(2dp)
level for each geometry by using the Gaussian 09 Revision D01 program1
DFT calculations
employed a fine integration grid (ie 75 radial shells with 302 angular points per shell) At
that level the B3LYP optimised structure displayed a small imaginary frequency (3i cm-1)
which vanished upon reoptimisation with tighter optimisation thresholds and an ultrafine
integration grid (ie 99 radial shells with 590 angular points per shell) Optimisations for
the complexes with benzene were performed including correction for basis-set
superposition error (BSSE) by way of the Counterpoise method2 1H magnetic shieldings
were converted into relative chemical shifts using the 1H magnetic shielding in TMS
computed at the same respective levels The energies were converted into enthalpies and
Gibbs free energies using standard thermodynamic corrections from the frequency
calculations for each levelComplete basis set calculations were performed using the
extrapolation scheme by Helgaker and coworkers3 This procedure is based on calculations
with Dunnings correlation-consistent basis sets4 with increasing cardinal numbers and
involves separate extrapolation for HF and the second-order perturbation correction E(2)
using inverse exponential and cubic fits respectively We did this for the calculated
absolute energies (not corrected for BSSE) from MP2 (and SCS-MP2)aug-cc-pVxZ single
points (x = D T Q) on MP2aug-cc-pVDZ optimised geometries (HF single points up to aug-
cc-pV5Z basis) Extrapolations of energies obtained including Counterpoise corrections or
using an inverse quadratic fit for E(2) afforded very similar CBS limits for each system all
within ca plusmn04 kcalmol of the standard fit (slightly larger variations up to plusmn06 kcalmol
were obtained when both BSSE corrections and an inverse quadratic fit were used see
Tables S2-S5 for details and results) When complexation energies rather than absolute
energies were extrapolated similar standard deviations were obtained from the fitting
procedure (plusmn04 kcalmol Table S3) Because these fits of complexation energies do not
1 Gaussian 09 Revision D01 M J Frisch G W Trucks H B Schlegel G E Scuseria M A Robb J R CheesemanG Scalmani V Barone B Mennucci G A Petersson H Nakatsuji M Caricato X Li H P Hratchian A F IzmaylovJ Bloino G Zheng J L Sonnenberg M Hada M Ehara K Toyota R Fukuda J Hasegawa M Ishida T NakajimaY Honda O Kitao H Nakai T Vreven J A Montgomery Jr J E Peralta F Ogliaro M Bearpark J J Heyd EBrothers K N Kudin V N Staroverov R Kobayashi J Normand K Raghavachari A Rendell J C Burant S SIyengar J Tomasi M Cossi N Rega J M Millam M Klene J E Knox J B Cross V Bakken C Adamo J JaramilloR Gomperts R E Stratmann O Yazyev A J Austin R Cammi C Pomelli J W Ochterski R L Martin KMorokuma V G Zakrzewski G A Voth P Salvador J J Dannenberg S Dapprich A D Daniels Ouml Farkas J BForesman J V Ortiz J Cioslowski and D J Fox Gaussian Inc Wallingford CT 2009
2 (a) S F Boys F Bernardi Mol Phys 1970 19 553 (b) S Simon M Duran J J Dannenberg J Chem Phys 1996
105 11024
3 T Helgaker W Klopper H Koch J Noga J Chem Phys 1997 106 9639
4 (a) T H Dunning Jr J Chem Phys 1989 90 1007 (b) R A Kendall T H Dunning Jr R J Harrison J Chem
Phys 1992 96 6796 (c) D E Woon T H Dunning Jr J Chem Phys 1993 98 1358 (d) K A Peterson D E Woon
T H Dunning Jr J Chem Phys 1994 100 7410 (e) A K Wilson T van Mourik T H Dunning Jr J Mol Struct
(Theochem) 1996 388 339
S3
show the proper convergence behavior of those using absolute energies (Figure S1) we
used only the latter (for which the basis sets were designed) We report the standard fit
results according to Helgaker et al3 (ie without Counterpoise correction and using an
inverse cubic fit) and use the plusmn04 kcalmol variation as a conservative error estimate
The MP2aug-cc-pVDZ total electron densitiy was evaluated for the geometry of 3C6H6
optimised at that level (optimisation done including Counterpoise correction) and was
used to run QTAIM (quantum theory of atoms in molecules)5 and NCI (non-covalent
interactions) calculations6 using the AIMALL7 and NCIPLOT 30 programs6 respectively
Experimental Details
All cis-123456-hexafluorocyclohexane was synthesised in 12-steps as a colourless solid (cf
reference 4 of the main paper) mp 206ndash208 ˚C (CH2Cl2)1H NMR (700 MHz CD2Cl2) δH 540-
523 (3H m Heq) and 461-446 (2H m Hax)13C NMR (125 MHz CD2Cl2) δC 895-843 (6C m)
Melting points were determined on a Reichert hot stage microscope and are uncorrected
1H NMR measurements were carried out on a Bruker Avance III 700 spectrometer equipped
with a TXI probe operating at 700 MHz using the deuterated solvent as the reference for
internal deuterium lock 13C NMR measurements were carried out on a Bruker Avance III HD
spectrometer equipped with a BBFO probe operating at 125 MHz with broadband 1H
decoupling using the deuterated solvent as the reference for internal deuterium lock The
chemical shift data are given as δ in units of parts per million (ppm) relative to
tetramethylsilane (TMS) where δ (TMS) = 000 ppm Each spectrum was referenced to the
residual solvent signal The solutions for NMR analysis were prepared by mixing
hexafluorocyclohexane with d2-dichloromethane (CD2Cl2) or d6-benzene (C6D6) and sonicating
the mixture for 30 s Any remaining solids were allowed to settle before the solution was
decanted to a 5 mm NMR tube The final concentration of the solutions was estimated to be le
1 mgmL-1
5 R F W Bader Atoms in Molecules A Quantum Theory Clarendon Oxford 1990
6 E Johnson S Keinan P Mori-Saacutenchez J Contreras-Garciacutea A Cohen W Yang J Am Chem Soc 2010 132 6498
7 AIMAll (Version 141123) T A Keith TK Gristmill Software Overland Park KS USA 2013 (aimtkgristmillcom)
S4
Table S1 Distances between the benzene ring and the cyclohexane axial hydrogen atoms C-
H (angstroms) and binding energies (kcal mol-1) for raw potential energies (E)
enthalpies (H) and Gibbs free energies (G) for compounds 3-53 4 5
C-H 3105 Aring 3442 Aring ---
B3LYP E -212 -075 ---
H -130 -004 ---
G +612 +698 ---
C-H 2694 Aring 2786 Aring 2834 Aring
B3LYP-D3 E -706 -484 -340
H -680 -471 -263
G +463 +592 +527
C-H 2710 Aring 2805 Aring 2868 Aring
MP2[a] E -695 -488 -317
H -613 -417 -240
G +128 +285 +550[a]
MP2 thermal corrections were obtained from B3LYP-D3def2-TZVP frequencies calculated fromB3LYP-D3def2-TZVP equilibrium geometry
S5
Table S2 Compounds 3 and 4 binding energies (kcal mol-1) and C-H distances (angstroms)obtained at different levels
[b]Single point energy calculations on MP2aug-cc-pVDZ optimised geometries
[c]MP2 and SCS-MP2 levels used thermal corrections obtained from B3LYP-D3def2-TZVP frequency
calculations on B3LYP-D3def2-TZVP geometries
S6
Table S3 Compounds 3 and 4 binding energies (kcal mol-1) obtained with aug-cc-pVXZ basissets (X = 2 3 and 4 X = 5 for the HF method was also used) Complete basis set (CBS) energieswere computed from the binding energies in kcal mol-1
Compound 3 Compound 4
HFCBS[a]
-013 +- 0009899 +141+- +- 0002333
E(2)
aug-cc-pVDZ -985 -887E
(2)aug-cc-pVTZ -875 -799
E(2)
aug-cc-pVQZ -781 -714
E(2)
CBS[b]
-780 +-03852 -716 +-03643E
(2)CBS
[c]-736 +- 03808 -679 +- 03719
MP2CBS[d]
-793 +-0395099 -575 +-0366633
E(2)
(SCS)aug-cc-pVDZ -828 -746E
(2)(SCS)aug-cc-pVTZ -724 -659
E(2)
(SCS)aug-cc-pVQZ -623 -569
E(2)
(SCS)CBS[b]
-626 +- 04336 -573 +- 03943E
(2)(SCS)CBS
[c]-581 +- 04432 -535 +- 04086
SCS-MP2CBS[e]
-639 +- 0443499 -432 +- 0396633SCS-MP2CBS
[f]-594 +- 0453099 -394 +- 0410933
[a]Using the equation E(HF) = a + be
-cXwith X = 2 3 4 and 5 from HF=aug-cc-pVXZ energies in Table X
[b]Using the equation E
(2)= a + bX
-3
[c]Using the equation E
(2)= a + bX
-2
[d]MP2CBS = HFCBS + E
(2)CBS
[e]SCS-MP2CBS = HFCBS + E
(2)(SCS)CBS for the equation E
(2)= a + bX
-3
[f]SCS-MP2CBS = HFCBS + E
(2)(SCS)CBS for the equation E
(2)= a + bX
-2
S7
Table S4 Absolute energies (atomic units) for each monomer and complexes with benzene computed by using aug-cc-pVXZ basis sets (X = 2 3 and 4 and X= 5 for the HF method) Complete basis set (CBS) extrapolated energies obtained from such energies and the fitting errors are indicated for each case
Table S5 Binding energies (kcal mol-1) obtained from CBS absolute energies showed in TableS4 for compounds 3 and 4
3 4
HFCBS -013 +141
HFCBS (BSSE) -044 +089
E(2)CBS[a] -781 -714
E(2)CBS[b] -737 -678
E(2)CBS[a] (BSSE) -749 -690
E(2)CBS[b] (BSSE) -806 -732
MP2CBS[c] -793 -575
MP2CBS[d] -750 -537
MP2CBS[c] (BSSE) -762 -549
MP2CBS[d] (BSSE) -850 -643
E(2)(SCS)CBS[a] -626 -574
E(2) (SCS)CBS[b] -582 -535
SCS-MP2CBS[c] -639 -433
SCS-MP2CBS[d] -595 -394
[a]E
(2)= a + bX
-3from Table S4
[b]E
(2)= a + bX
-2from Table S4
[c]MP2CBS and SCS-MP2 = HFCBS + E
(2)CBS E
(2)CBS value used was that obtained from equation E
(2)= a + bX
-3
[d]MP2CBS and SCS-MP2 = HFCBS + E
(2)CBS E
(2)CBS value used was that obtained from equation E
(2)= a + bX
-2
S9
Plots for Relative Energies (Table S3)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Plots for Absolute Energies (Table S4)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Figure S1 Plots of equations E (2)CBS = a + bX-3 and E (2)CBS = a + bX-2 for X = 2 3 and 4 (basis set
aug-cc-pVXZ) E (2)CBS values used from Table S3 (relative energies) and Table S4 (absolute
energies)
S10
Table S6 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
Table S7 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYP-D3def2-TZVP optimised geometries with BSSE corrections included
Table S9 Calculated 1H isotropic shielding tensors for ghostrdquo atoms obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
3C6H6 4C6H6
Hax 118 088
Heq (down) 036 034
Heq (up) --- 028
S14
a) b) c)
Figure S2 Results from topological analysis of the total electron density of 3C6H6 (MP2aug-cc-
pVDZMP2aug-cc-pVDZ level) a) Molecular graph from Atoms-in-Molecules analysis green
bond critical points (BCPs) red ring critical points blue cage critical point Key properties of the
three BCPs connecting 3 to C6H6 = 0007 2 = +0020 ellipticity=+0393 K = -00006 V =
00038 G = +00044 (all in au) b) NCI isosurfaces for 3C6H6 obtained with reduced density
gradient (RDG) = 05 and blue-green-red color scale ranging from minus002 au lt sign(λ2)ρ(r) lt +002
au c) Graph of RDG versus sign(λ2)ρ for 3C6H6 The regions between the axial H atoms of 3 and
the closest C atoms of benzene are included in the downward peak at negative sign(λ2)ρ
indicating weakly attractive interactions
S15
Figure S3 Experimental 1H NMR spectra (700 MHz) of 3 in CD2Cl2 (bottom) and C6D6 (top)
illustrating the upfield shifts of the signals on going into the aromatic solvent An impurity of
diethyl ether was present in the NMR samples
Figure S4 Experimental 1H 1D gradient selective TOCSY NMR spectra (700 MHz) of 3 in CD2Cl2
(top) irradiated on the Hax signal at 459 ppm and 1H NMR of 3 in CD2Cl2 (bottom) illustrating the
overlap of the Heq protons of 3 with the residual CD2Cl2 solvent signal
S3
show the proper convergence behavior of those using absolute energies (Figure S1) we
used only the latter (for which the basis sets were designed) We report the standard fit
results according to Helgaker et al3 (ie without Counterpoise correction and using an
inverse cubic fit) and use the plusmn04 kcalmol variation as a conservative error estimate
The MP2aug-cc-pVDZ total electron densitiy was evaluated for the geometry of 3C6H6
optimised at that level (optimisation done including Counterpoise correction) and was
used to run QTAIM (quantum theory of atoms in molecules)5 and NCI (non-covalent
interactions) calculations6 using the AIMALL7 and NCIPLOT 30 programs6 respectively
Experimental Details
All cis-123456-hexafluorocyclohexane was synthesised in 12-steps as a colourless solid (cf
reference 4 of the main paper) mp 206ndash208 ˚C (CH2Cl2)1H NMR (700 MHz CD2Cl2) δH 540-
523 (3H m Heq) and 461-446 (2H m Hax)13C NMR (125 MHz CD2Cl2) δC 895-843 (6C m)
Melting points were determined on a Reichert hot stage microscope and are uncorrected
1H NMR measurements were carried out on a Bruker Avance III 700 spectrometer equipped
with a TXI probe operating at 700 MHz using the deuterated solvent as the reference for
internal deuterium lock 13C NMR measurements were carried out on a Bruker Avance III HD
spectrometer equipped with a BBFO probe operating at 125 MHz with broadband 1H
decoupling using the deuterated solvent as the reference for internal deuterium lock The
chemical shift data are given as δ in units of parts per million (ppm) relative to
tetramethylsilane (TMS) where δ (TMS) = 000 ppm Each spectrum was referenced to the
residual solvent signal The solutions for NMR analysis were prepared by mixing
hexafluorocyclohexane with d2-dichloromethane (CD2Cl2) or d6-benzene (C6D6) and sonicating
the mixture for 30 s Any remaining solids were allowed to settle before the solution was
decanted to a 5 mm NMR tube The final concentration of the solutions was estimated to be le
1 mgmL-1
5 R F W Bader Atoms in Molecules A Quantum Theory Clarendon Oxford 1990
6 E Johnson S Keinan P Mori-Saacutenchez J Contreras-Garciacutea A Cohen W Yang J Am Chem Soc 2010 132 6498
7 AIMAll (Version 141123) T A Keith TK Gristmill Software Overland Park KS USA 2013 (aimtkgristmillcom)
S4
Table S1 Distances between the benzene ring and the cyclohexane axial hydrogen atoms C-
H (angstroms) and binding energies (kcal mol-1) for raw potential energies (E)
enthalpies (H) and Gibbs free energies (G) for compounds 3-53 4 5
C-H 3105 Aring 3442 Aring ---
B3LYP E -212 -075 ---
H -130 -004 ---
G +612 +698 ---
C-H 2694 Aring 2786 Aring 2834 Aring
B3LYP-D3 E -706 -484 -340
H -680 -471 -263
G +463 +592 +527
C-H 2710 Aring 2805 Aring 2868 Aring
MP2[a] E -695 -488 -317
H -613 -417 -240
G +128 +285 +550[a]
MP2 thermal corrections were obtained from B3LYP-D3def2-TZVP frequencies calculated fromB3LYP-D3def2-TZVP equilibrium geometry
S5
Table S2 Compounds 3 and 4 binding energies (kcal mol-1) and C-H distances (angstroms)obtained at different levels
[b]Single point energy calculations on MP2aug-cc-pVDZ optimised geometries
[c]MP2 and SCS-MP2 levels used thermal corrections obtained from B3LYP-D3def2-TZVP frequency
calculations on B3LYP-D3def2-TZVP geometries
S6
Table S3 Compounds 3 and 4 binding energies (kcal mol-1) obtained with aug-cc-pVXZ basissets (X = 2 3 and 4 X = 5 for the HF method was also used) Complete basis set (CBS) energieswere computed from the binding energies in kcal mol-1
Compound 3 Compound 4
HFCBS[a]
-013 +- 0009899 +141+- +- 0002333
E(2)
aug-cc-pVDZ -985 -887E
(2)aug-cc-pVTZ -875 -799
E(2)
aug-cc-pVQZ -781 -714
E(2)
CBS[b]
-780 +-03852 -716 +-03643E
(2)CBS
[c]-736 +- 03808 -679 +- 03719
MP2CBS[d]
-793 +-0395099 -575 +-0366633
E(2)
(SCS)aug-cc-pVDZ -828 -746E
(2)(SCS)aug-cc-pVTZ -724 -659
E(2)
(SCS)aug-cc-pVQZ -623 -569
E(2)
(SCS)CBS[b]
-626 +- 04336 -573 +- 03943E
(2)(SCS)CBS
[c]-581 +- 04432 -535 +- 04086
SCS-MP2CBS[e]
-639 +- 0443499 -432 +- 0396633SCS-MP2CBS
[f]-594 +- 0453099 -394 +- 0410933
[a]Using the equation E(HF) = a + be
-cXwith X = 2 3 4 and 5 from HF=aug-cc-pVXZ energies in Table X
[b]Using the equation E
(2)= a + bX
-3
[c]Using the equation E
(2)= a + bX
-2
[d]MP2CBS = HFCBS + E
(2)CBS
[e]SCS-MP2CBS = HFCBS + E
(2)(SCS)CBS for the equation E
(2)= a + bX
-3
[f]SCS-MP2CBS = HFCBS + E
(2)(SCS)CBS for the equation E
(2)= a + bX
-2
S7
Table S4 Absolute energies (atomic units) for each monomer and complexes with benzene computed by using aug-cc-pVXZ basis sets (X = 2 3 and 4 and X= 5 for the HF method) Complete basis set (CBS) extrapolated energies obtained from such energies and the fitting errors are indicated for each case
Table S5 Binding energies (kcal mol-1) obtained from CBS absolute energies showed in TableS4 for compounds 3 and 4
3 4
HFCBS -013 +141
HFCBS (BSSE) -044 +089
E(2)CBS[a] -781 -714
E(2)CBS[b] -737 -678
E(2)CBS[a] (BSSE) -749 -690
E(2)CBS[b] (BSSE) -806 -732
MP2CBS[c] -793 -575
MP2CBS[d] -750 -537
MP2CBS[c] (BSSE) -762 -549
MP2CBS[d] (BSSE) -850 -643
E(2)(SCS)CBS[a] -626 -574
E(2) (SCS)CBS[b] -582 -535
SCS-MP2CBS[c] -639 -433
SCS-MP2CBS[d] -595 -394
[a]E
(2)= a + bX
-3from Table S4
[b]E
(2)= a + bX
-2from Table S4
[c]MP2CBS and SCS-MP2 = HFCBS + E
(2)CBS E
(2)CBS value used was that obtained from equation E
(2)= a + bX
-3
[d]MP2CBS and SCS-MP2 = HFCBS + E
(2)CBS E
(2)CBS value used was that obtained from equation E
(2)= a + bX
-2
S9
Plots for Relative Energies (Table S3)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Plots for Absolute Energies (Table S4)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Figure S1 Plots of equations E (2)CBS = a + bX-3 and E (2)CBS = a + bX-2 for X = 2 3 and 4 (basis set
aug-cc-pVXZ) E (2)CBS values used from Table S3 (relative energies) and Table S4 (absolute
energies)
S10
Table S6 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
Table S7 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYP-D3def2-TZVP optimised geometries with BSSE corrections included
Table S9 Calculated 1H isotropic shielding tensors for ghostrdquo atoms obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
3C6H6 4C6H6
Hax 118 088
Heq (down) 036 034
Heq (up) --- 028
S14
a) b) c)
Figure S2 Results from topological analysis of the total electron density of 3C6H6 (MP2aug-cc-
pVDZMP2aug-cc-pVDZ level) a) Molecular graph from Atoms-in-Molecules analysis green
bond critical points (BCPs) red ring critical points blue cage critical point Key properties of the
three BCPs connecting 3 to C6H6 = 0007 2 = +0020 ellipticity=+0393 K = -00006 V =
00038 G = +00044 (all in au) b) NCI isosurfaces for 3C6H6 obtained with reduced density
gradient (RDG) = 05 and blue-green-red color scale ranging from minus002 au lt sign(λ2)ρ(r) lt +002
au c) Graph of RDG versus sign(λ2)ρ for 3C6H6 The regions between the axial H atoms of 3 and
the closest C atoms of benzene are included in the downward peak at negative sign(λ2)ρ
indicating weakly attractive interactions
S15
Figure S3 Experimental 1H NMR spectra (700 MHz) of 3 in CD2Cl2 (bottom) and C6D6 (top)
illustrating the upfield shifts of the signals on going into the aromatic solvent An impurity of
diethyl ether was present in the NMR samples
Figure S4 Experimental 1H 1D gradient selective TOCSY NMR spectra (700 MHz) of 3 in CD2Cl2
(top) irradiated on the Hax signal at 459 ppm and 1H NMR of 3 in CD2Cl2 (bottom) illustrating the
overlap of the Heq protons of 3 with the residual CD2Cl2 solvent signal
S4
Table S1 Distances between the benzene ring and the cyclohexane axial hydrogen atoms C-
H (angstroms) and binding energies (kcal mol-1) for raw potential energies (E)
enthalpies (H) and Gibbs free energies (G) for compounds 3-53 4 5
C-H 3105 Aring 3442 Aring ---
B3LYP E -212 -075 ---
H -130 -004 ---
G +612 +698 ---
C-H 2694 Aring 2786 Aring 2834 Aring
B3LYP-D3 E -706 -484 -340
H -680 -471 -263
G +463 +592 +527
C-H 2710 Aring 2805 Aring 2868 Aring
MP2[a] E -695 -488 -317
H -613 -417 -240
G +128 +285 +550[a]
MP2 thermal corrections were obtained from B3LYP-D3def2-TZVP frequencies calculated fromB3LYP-D3def2-TZVP equilibrium geometry
S5
Table S2 Compounds 3 and 4 binding energies (kcal mol-1) and C-H distances (angstroms)obtained at different levels
[b]Single point energy calculations on MP2aug-cc-pVDZ optimised geometries
[c]MP2 and SCS-MP2 levels used thermal corrections obtained from B3LYP-D3def2-TZVP frequency
calculations on B3LYP-D3def2-TZVP geometries
S6
Table S3 Compounds 3 and 4 binding energies (kcal mol-1) obtained with aug-cc-pVXZ basissets (X = 2 3 and 4 X = 5 for the HF method was also used) Complete basis set (CBS) energieswere computed from the binding energies in kcal mol-1
Compound 3 Compound 4
HFCBS[a]
-013 +- 0009899 +141+- +- 0002333
E(2)
aug-cc-pVDZ -985 -887E
(2)aug-cc-pVTZ -875 -799
E(2)
aug-cc-pVQZ -781 -714
E(2)
CBS[b]
-780 +-03852 -716 +-03643E
(2)CBS
[c]-736 +- 03808 -679 +- 03719
MP2CBS[d]
-793 +-0395099 -575 +-0366633
E(2)
(SCS)aug-cc-pVDZ -828 -746E
(2)(SCS)aug-cc-pVTZ -724 -659
E(2)
(SCS)aug-cc-pVQZ -623 -569
E(2)
(SCS)CBS[b]
-626 +- 04336 -573 +- 03943E
(2)(SCS)CBS
[c]-581 +- 04432 -535 +- 04086
SCS-MP2CBS[e]
-639 +- 0443499 -432 +- 0396633SCS-MP2CBS
[f]-594 +- 0453099 -394 +- 0410933
[a]Using the equation E(HF) = a + be
-cXwith X = 2 3 4 and 5 from HF=aug-cc-pVXZ energies in Table X
[b]Using the equation E
(2)= a + bX
-3
[c]Using the equation E
(2)= a + bX
-2
[d]MP2CBS = HFCBS + E
(2)CBS
[e]SCS-MP2CBS = HFCBS + E
(2)(SCS)CBS for the equation E
(2)= a + bX
-3
[f]SCS-MP2CBS = HFCBS + E
(2)(SCS)CBS for the equation E
(2)= a + bX
-2
S7
Table S4 Absolute energies (atomic units) for each monomer and complexes with benzene computed by using aug-cc-pVXZ basis sets (X = 2 3 and 4 and X= 5 for the HF method) Complete basis set (CBS) extrapolated energies obtained from such energies and the fitting errors are indicated for each case
Table S5 Binding energies (kcal mol-1) obtained from CBS absolute energies showed in TableS4 for compounds 3 and 4
3 4
HFCBS -013 +141
HFCBS (BSSE) -044 +089
E(2)CBS[a] -781 -714
E(2)CBS[b] -737 -678
E(2)CBS[a] (BSSE) -749 -690
E(2)CBS[b] (BSSE) -806 -732
MP2CBS[c] -793 -575
MP2CBS[d] -750 -537
MP2CBS[c] (BSSE) -762 -549
MP2CBS[d] (BSSE) -850 -643
E(2)(SCS)CBS[a] -626 -574
E(2) (SCS)CBS[b] -582 -535
SCS-MP2CBS[c] -639 -433
SCS-MP2CBS[d] -595 -394
[a]E
(2)= a + bX
-3from Table S4
[b]E
(2)= a + bX
-2from Table S4
[c]MP2CBS and SCS-MP2 = HFCBS + E
(2)CBS E
(2)CBS value used was that obtained from equation E
(2)= a + bX
-3
[d]MP2CBS and SCS-MP2 = HFCBS + E
(2)CBS E
(2)CBS value used was that obtained from equation E
(2)= a + bX
-2
S9
Plots for Relative Energies (Table S3)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Plots for Absolute Energies (Table S4)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Figure S1 Plots of equations E (2)CBS = a + bX-3 and E (2)CBS = a + bX-2 for X = 2 3 and 4 (basis set
aug-cc-pVXZ) E (2)CBS values used from Table S3 (relative energies) and Table S4 (absolute
energies)
S10
Table S6 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
Table S7 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYP-D3def2-TZVP optimised geometries with BSSE corrections included
Table S9 Calculated 1H isotropic shielding tensors for ghostrdquo atoms obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
3C6H6 4C6H6
Hax 118 088
Heq (down) 036 034
Heq (up) --- 028
S14
a) b) c)
Figure S2 Results from topological analysis of the total electron density of 3C6H6 (MP2aug-cc-
pVDZMP2aug-cc-pVDZ level) a) Molecular graph from Atoms-in-Molecules analysis green
bond critical points (BCPs) red ring critical points blue cage critical point Key properties of the
three BCPs connecting 3 to C6H6 = 0007 2 = +0020 ellipticity=+0393 K = -00006 V =
00038 G = +00044 (all in au) b) NCI isosurfaces for 3C6H6 obtained with reduced density
gradient (RDG) = 05 and blue-green-red color scale ranging from minus002 au lt sign(λ2)ρ(r) lt +002
au c) Graph of RDG versus sign(λ2)ρ for 3C6H6 The regions between the axial H atoms of 3 and
the closest C atoms of benzene are included in the downward peak at negative sign(λ2)ρ
indicating weakly attractive interactions
S15
Figure S3 Experimental 1H NMR spectra (700 MHz) of 3 in CD2Cl2 (bottom) and C6D6 (top)
illustrating the upfield shifts of the signals on going into the aromatic solvent An impurity of
diethyl ether was present in the NMR samples
Figure S4 Experimental 1H 1D gradient selective TOCSY NMR spectra (700 MHz) of 3 in CD2Cl2
(top) irradiated on the Hax signal at 459 ppm and 1H NMR of 3 in CD2Cl2 (bottom) illustrating the
overlap of the Heq protons of 3 with the residual CD2Cl2 solvent signal
S5
Table S2 Compounds 3 and 4 binding energies (kcal mol-1) and C-H distances (angstroms)obtained at different levels
[b]Single point energy calculations on MP2aug-cc-pVDZ optimised geometries
[c]MP2 and SCS-MP2 levels used thermal corrections obtained from B3LYP-D3def2-TZVP frequency
calculations on B3LYP-D3def2-TZVP geometries
S6
Table S3 Compounds 3 and 4 binding energies (kcal mol-1) obtained with aug-cc-pVXZ basissets (X = 2 3 and 4 X = 5 for the HF method was also used) Complete basis set (CBS) energieswere computed from the binding energies in kcal mol-1
Compound 3 Compound 4
HFCBS[a]
-013 +- 0009899 +141+- +- 0002333
E(2)
aug-cc-pVDZ -985 -887E
(2)aug-cc-pVTZ -875 -799
E(2)
aug-cc-pVQZ -781 -714
E(2)
CBS[b]
-780 +-03852 -716 +-03643E
(2)CBS
[c]-736 +- 03808 -679 +- 03719
MP2CBS[d]
-793 +-0395099 -575 +-0366633
E(2)
(SCS)aug-cc-pVDZ -828 -746E
(2)(SCS)aug-cc-pVTZ -724 -659
E(2)
(SCS)aug-cc-pVQZ -623 -569
E(2)
(SCS)CBS[b]
-626 +- 04336 -573 +- 03943E
(2)(SCS)CBS
[c]-581 +- 04432 -535 +- 04086
SCS-MP2CBS[e]
-639 +- 0443499 -432 +- 0396633SCS-MP2CBS
[f]-594 +- 0453099 -394 +- 0410933
[a]Using the equation E(HF) = a + be
-cXwith X = 2 3 4 and 5 from HF=aug-cc-pVXZ energies in Table X
[b]Using the equation E
(2)= a + bX
-3
[c]Using the equation E
(2)= a + bX
-2
[d]MP2CBS = HFCBS + E
(2)CBS
[e]SCS-MP2CBS = HFCBS + E
(2)(SCS)CBS for the equation E
(2)= a + bX
-3
[f]SCS-MP2CBS = HFCBS + E
(2)(SCS)CBS for the equation E
(2)= a + bX
-2
S7
Table S4 Absolute energies (atomic units) for each monomer and complexes with benzene computed by using aug-cc-pVXZ basis sets (X = 2 3 and 4 and X= 5 for the HF method) Complete basis set (CBS) extrapolated energies obtained from such energies and the fitting errors are indicated for each case
Table S5 Binding energies (kcal mol-1) obtained from CBS absolute energies showed in TableS4 for compounds 3 and 4
3 4
HFCBS -013 +141
HFCBS (BSSE) -044 +089
E(2)CBS[a] -781 -714
E(2)CBS[b] -737 -678
E(2)CBS[a] (BSSE) -749 -690
E(2)CBS[b] (BSSE) -806 -732
MP2CBS[c] -793 -575
MP2CBS[d] -750 -537
MP2CBS[c] (BSSE) -762 -549
MP2CBS[d] (BSSE) -850 -643
E(2)(SCS)CBS[a] -626 -574
E(2) (SCS)CBS[b] -582 -535
SCS-MP2CBS[c] -639 -433
SCS-MP2CBS[d] -595 -394
[a]E
(2)= a + bX
-3from Table S4
[b]E
(2)= a + bX
-2from Table S4
[c]MP2CBS and SCS-MP2 = HFCBS + E
(2)CBS E
(2)CBS value used was that obtained from equation E
(2)= a + bX
-3
[d]MP2CBS and SCS-MP2 = HFCBS + E
(2)CBS E
(2)CBS value used was that obtained from equation E
(2)= a + bX
-2
S9
Plots for Relative Energies (Table S3)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Plots for Absolute Energies (Table S4)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Figure S1 Plots of equations E (2)CBS = a + bX-3 and E (2)CBS = a + bX-2 for X = 2 3 and 4 (basis set
aug-cc-pVXZ) E (2)CBS values used from Table S3 (relative energies) and Table S4 (absolute
energies)
S10
Table S6 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
Table S7 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYP-D3def2-TZVP optimised geometries with BSSE corrections included
Table S9 Calculated 1H isotropic shielding tensors for ghostrdquo atoms obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
3C6H6 4C6H6
Hax 118 088
Heq (down) 036 034
Heq (up) --- 028
S14
a) b) c)
Figure S2 Results from topological analysis of the total electron density of 3C6H6 (MP2aug-cc-
pVDZMP2aug-cc-pVDZ level) a) Molecular graph from Atoms-in-Molecules analysis green
bond critical points (BCPs) red ring critical points blue cage critical point Key properties of the
three BCPs connecting 3 to C6H6 = 0007 2 = +0020 ellipticity=+0393 K = -00006 V =
00038 G = +00044 (all in au) b) NCI isosurfaces for 3C6H6 obtained with reduced density
gradient (RDG) = 05 and blue-green-red color scale ranging from minus002 au lt sign(λ2)ρ(r) lt +002
au c) Graph of RDG versus sign(λ2)ρ for 3C6H6 The regions between the axial H atoms of 3 and
the closest C atoms of benzene are included in the downward peak at negative sign(λ2)ρ
indicating weakly attractive interactions
S15
Figure S3 Experimental 1H NMR spectra (700 MHz) of 3 in CD2Cl2 (bottom) and C6D6 (top)
illustrating the upfield shifts of the signals on going into the aromatic solvent An impurity of
diethyl ether was present in the NMR samples
Figure S4 Experimental 1H 1D gradient selective TOCSY NMR spectra (700 MHz) of 3 in CD2Cl2
(top) irradiated on the Hax signal at 459 ppm and 1H NMR of 3 in CD2Cl2 (bottom) illustrating the
overlap of the Heq protons of 3 with the residual CD2Cl2 solvent signal
S6
Table S3 Compounds 3 and 4 binding energies (kcal mol-1) obtained with aug-cc-pVXZ basissets (X = 2 3 and 4 X = 5 for the HF method was also used) Complete basis set (CBS) energieswere computed from the binding energies in kcal mol-1
Compound 3 Compound 4
HFCBS[a]
-013 +- 0009899 +141+- +- 0002333
E(2)
aug-cc-pVDZ -985 -887E
(2)aug-cc-pVTZ -875 -799
E(2)
aug-cc-pVQZ -781 -714
E(2)
CBS[b]
-780 +-03852 -716 +-03643E
(2)CBS
[c]-736 +- 03808 -679 +- 03719
MP2CBS[d]
-793 +-0395099 -575 +-0366633
E(2)
(SCS)aug-cc-pVDZ -828 -746E
(2)(SCS)aug-cc-pVTZ -724 -659
E(2)
(SCS)aug-cc-pVQZ -623 -569
E(2)
(SCS)CBS[b]
-626 +- 04336 -573 +- 03943E
(2)(SCS)CBS
[c]-581 +- 04432 -535 +- 04086
SCS-MP2CBS[e]
-639 +- 0443499 -432 +- 0396633SCS-MP2CBS
[f]-594 +- 0453099 -394 +- 0410933
[a]Using the equation E(HF) = a + be
-cXwith X = 2 3 4 and 5 from HF=aug-cc-pVXZ energies in Table X
[b]Using the equation E
(2)= a + bX
-3
[c]Using the equation E
(2)= a + bX
-2
[d]MP2CBS = HFCBS + E
(2)CBS
[e]SCS-MP2CBS = HFCBS + E
(2)(SCS)CBS for the equation E
(2)= a + bX
-3
[f]SCS-MP2CBS = HFCBS + E
(2)(SCS)CBS for the equation E
(2)= a + bX
-2
S7
Table S4 Absolute energies (atomic units) for each monomer and complexes with benzene computed by using aug-cc-pVXZ basis sets (X = 2 3 and 4 and X= 5 for the HF method) Complete basis set (CBS) extrapolated energies obtained from such energies and the fitting errors are indicated for each case
Table S5 Binding energies (kcal mol-1) obtained from CBS absolute energies showed in TableS4 for compounds 3 and 4
3 4
HFCBS -013 +141
HFCBS (BSSE) -044 +089
E(2)CBS[a] -781 -714
E(2)CBS[b] -737 -678
E(2)CBS[a] (BSSE) -749 -690
E(2)CBS[b] (BSSE) -806 -732
MP2CBS[c] -793 -575
MP2CBS[d] -750 -537
MP2CBS[c] (BSSE) -762 -549
MP2CBS[d] (BSSE) -850 -643
E(2)(SCS)CBS[a] -626 -574
E(2) (SCS)CBS[b] -582 -535
SCS-MP2CBS[c] -639 -433
SCS-MP2CBS[d] -595 -394
[a]E
(2)= a + bX
-3from Table S4
[b]E
(2)= a + bX
-2from Table S4
[c]MP2CBS and SCS-MP2 = HFCBS + E
(2)CBS E
(2)CBS value used was that obtained from equation E
(2)= a + bX
-3
[d]MP2CBS and SCS-MP2 = HFCBS + E
(2)CBS E
(2)CBS value used was that obtained from equation E
(2)= a + bX
-2
S9
Plots for Relative Energies (Table S3)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Plots for Absolute Energies (Table S4)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Figure S1 Plots of equations E (2)CBS = a + bX-3 and E (2)CBS = a + bX-2 for X = 2 3 and 4 (basis set
aug-cc-pVXZ) E (2)CBS values used from Table S3 (relative energies) and Table S4 (absolute
energies)
S10
Table S6 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
Table S7 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYP-D3def2-TZVP optimised geometries with BSSE corrections included
Table S9 Calculated 1H isotropic shielding tensors for ghostrdquo atoms obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
3C6H6 4C6H6
Hax 118 088
Heq (down) 036 034
Heq (up) --- 028
S14
a) b) c)
Figure S2 Results from topological analysis of the total electron density of 3C6H6 (MP2aug-cc-
pVDZMP2aug-cc-pVDZ level) a) Molecular graph from Atoms-in-Molecules analysis green
bond critical points (BCPs) red ring critical points blue cage critical point Key properties of the
three BCPs connecting 3 to C6H6 = 0007 2 = +0020 ellipticity=+0393 K = -00006 V =
00038 G = +00044 (all in au) b) NCI isosurfaces for 3C6H6 obtained with reduced density
gradient (RDG) = 05 and blue-green-red color scale ranging from minus002 au lt sign(λ2)ρ(r) lt +002
au c) Graph of RDG versus sign(λ2)ρ for 3C6H6 The regions between the axial H atoms of 3 and
the closest C atoms of benzene are included in the downward peak at negative sign(λ2)ρ
indicating weakly attractive interactions
S15
Figure S3 Experimental 1H NMR spectra (700 MHz) of 3 in CD2Cl2 (bottom) and C6D6 (top)
illustrating the upfield shifts of the signals on going into the aromatic solvent An impurity of
diethyl ether was present in the NMR samples
Figure S4 Experimental 1H 1D gradient selective TOCSY NMR spectra (700 MHz) of 3 in CD2Cl2
(top) irradiated on the Hax signal at 459 ppm and 1H NMR of 3 in CD2Cl2 (bottom) illustrating the
overlap of the Heq protons of 3 with the residual CD2Cl2 solvent signal
S7
Table S4 Absolute energies (atomic units) for each monomer and complexes with benzene computed by using aug-cc-pVXZ basis sets (X = 2 3 and 4 and X= 5 for the HF method) Complete basis set (CBS) extrapolated energies obtained from such energies and the fitting errors are indicated for each case
Table S5 Binding energies (kcal mol-1) obtained from CBS absolute energies showed in TableS4 for compounds 3 and 4
3 4
HFCBS -013 +141
HFCBS (BSSE) -044 +089
E(2)CBS[a] -781 -714
E(2)CBS[b] -737 -678
E(2)CBS[a] (BSSE) -749 -690
E(2)CBS[b] (BSSE) -806 -732
MP2CBS[c] -793 -575
MP2CBS[d] -750 -537
MP2CBS[c] (BSSE) -762 -549
MP2CBS[d] (BSSE) -850 -643
E(2)(SCS)CBS[a] -626 -574
E(2) (SCS)CBS[b] -582 -535
SCS-MP2CBS[c] -639 -433
SCS-MP2CBS[d] -595 -394
[a]E
(2)= a + bX
-3from Table S4
[b]E
(2)= a + bX
-2from Table S4
[c]MP2CBS and SCS-MP2 = HFCBS + E
(2)CBS E
(2)CBS value used was that obtained from equation E
(2)= a + bX
-3
[d]MP2CBS and SCS-MP2 = HFCBS + E
(2)CBS E
(2)CBS value used was that obtained from equation E
(2)= a + bX
-2
S9
Plots for Relative Energies (Table S3)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Plots for Absolute Energies (Table S4)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Figure S1 Plots of equations E (2)CBS = a + bX-3 and E (2)CBS = a + bX-2 for X = 2 3 and 4 (basis set
aug-cc-pVXZ) E (2)CBS values used from Table S3 (relative energies) and Table S4 (absolute
energies)
S10
Table S6 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
Table S7 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYP-D3def2-TZVP optimised geometries with BSSE corrections included
Table S9 Calculated 1H isotropic shielding tensors for ghostrdquo atoms obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
3C6H6 4C6H6
Hax 118 088
Heq (down) 036 034
Heq (up) --- 028
S14
a) b) c)
Figure S2 Results from topological analysis of the total electron density of 3C6H6 (MP2aug-cc-
pVDZMP2aug-cc-pVDZ level) a) Molecular graph from Atoms-in-Molecules analysis green
bond critical points (BCPs) red ring critical points blue cage critical point Key properties of the
three BCPs connecting 3 to C6H6 = 0007 2 = +0020 ellipticity=+0393 K = -00006 V =
00038 G = +00044 (all in au) b) NCI isosurfaces for 3C6H6 obtained with reduced density
gradient (RDG) = 05 and blue-green-red color scale ranging from minus002 au lt sign(λ2)ρ(r) lt +002
au c) Graph of RDG versus sign(λ2)ρ for 3C6H6 The regions between the axial H atoms of 3 and
the closest C atoms of benzene are included in the downward peak at negative sign(λ2)ρ
indicating weakly attractive interactions
S15
Figure S3 Experimental 1H NMR spectra (700 MHz) of 3 in CD2Cl2 (bottom) and C6D6 (top)
illustrating the upfield shifts of the signals on going into the aromatic solvent An impurity of
diethyl ether was present in the NMR samples
Figure S4 Experimental 1H 1D gradient selective TOCSY NMR spectra (700 MHz) of 3 in CD2Cl2
(top) irradiated on the Hax signal at 459 ppm and 1H NMR of 3 in CD2Cl2 (bottom) illustrating the
overlap of the Heq protons of 3 with the residual CD2Cl2 solvent signal
S8
Table S5 Binding energies (kcal mol-1) obtained from CBS absolute energies showed in TableS4 for compounds 3 and 4
3 4
HFCBS -013 +141
HFCBS (BSSE) -044 +089
E(2)CBS[a] -781 -714
E(2)CBS[b] -737 -678
E(2)CBS[a] (BSSE) -749 -690
E(2)CBS[b] (BSSE) -806 -732
MP2CBS[c] -793 -575
MP2CBS[d] -750 -537
MP2CBS[c] (BSSE) -762 -549
MP2CBS[d] (BSSE) -850 -643
E(2)(SCS)CBS[a] -626 -574
E(2) (SCS)CBS[b] -582 -535
SCS-MP2CBS[c] -639 -433
SCS-MP2CBS[d] -595 -394
[a]E
(2)= a + bX
-3from Table S4
[b]E
(2)= a + bX
-2from Table S4
[c]MP2CBS and SCS-MP2 = HFCBS + E
(2)CBS E
(2)CBS value used was that obtained from equation E
(2)= a + bX
-3
[d]MP2CBS and SCS-MP2 = HFCBS + E
(2)CBS E
(2)CBS value used was that obtained from equation E
(2)= a + bX
-2
S9
Plots for Relative Energies (Table S3)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Plots for Absolute Energies (Table S4)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Figure S1 Plots of equations E (2)CBS = a + bX-3 and E (2)CBS = a + bX-2 for X = 2 3 and 4 (basis set
aug-cc-pVXZ) E (2)CBS values used from Table S3 (relative energies) and Table S4 (absolute
energies)
S10
Table S6 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
Table S7 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYP-D3def2-TZVP optimised geometries with BSSE corrections included
Table S9 Calculated 1H isotropic shielding tensors for ghostrdquo atoms obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
3C6H6 4C6H6
Hax 118 088
Heq (down) 036 034
Heq (up) --- 028
S14
a) b) c)
Figure S2 Results from topological analysis of the total electron density of 3C6H6 (MP2aug-cc-
pVDZMP2aug-cc-pVDZ level) a) Molecular graph from Atoms-in-Molecules analysis green
bond critical points (BCPs) red ring critical points blue cage critical point Key properties of the
three BCPs connecting 3 to C6H6 = 0007 2 = +0020 ellipticity=+0393 K = -00006 V =
00038 G = +00044 (all in au) b) NCI isosurfaces for 3C6H6 obtained with reduced density
gradient (RDG) = 05 and blue-green-red color scale ranging from minus002 au lt sign(λ2)ρ(r) lt +002
au c) Graph of RDG versus sign(λ2)ρ for 3C6H6 The regions between the axial H atoms of 3 and
the closest C atoms of benzene are included in the downward peak at negative sign(λ2)ρ
indicating weakly attractive interactions
S15
Figure S3 Experimental 1H NMR spectra (700 MHz) of 3 in CD2Cl2 (bottom) and C6D6 (top)
illustrating the upfield shifts of the signals on going into the aromatic solvent An impurity of
diethyl ether was present in the NMR samples
Figure S4 Experimental 1H 1D gradient selective TOCSY NMR spectra (700 MHz) of 3 in CD2Cl2
(top) irradiated on the Hax signal at 459 ppm and 1H NMR of 3 in CD2Cl2 (bottom) illustrating the
overlap of the Heq protons of 3 with the residual CD2Cl2 solvent signal
S9
Plots for Relative Energies (Table S3)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Plots for Absolute Energies (Table S4)
Compound 4 Compound 3
f(x) = a + bX-3
f(x) = a + bX-3
f(x) = a + bX-2
f(x) = a + bX-2
Figure S1 Plots of equations E (2)CBS = a + bX-3 and E (2)CBS = a + bX-2 for X = 2 3 and 4 (basis set
aug-cc-pVXZ) E (2)CBS values used from Table S3 (relative energies) and Table S4 (absolute
energies)
S10
Table S6 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
Table S7 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYP-D3def2-TZVP optimised geometries with BSSE corrections included
Table S9 Calculated 1H isotropic shielding tensors for ghostrdquo atoms obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
3C6H6 4C6H6
Hax 118 088
Heq (down) 036 034
Heq (up) --- 028
S14
a) b) c)
Figure S2 Results from topological analysis of the total electron density of 3C6H6 (MP2aug-cc-
pVDZMP2aug-cc-pVDZ level) a) Molecular graph from Atoms-in-Molecules analysis green
bond critical points (BCPs) red ring critical points blue cage critical point Key properties of the
three BCPs connecting 3 to C6H6 = 0007 2 = +0020 ellipticity=+0393 K = -00006 V =
00038 G = +00044 (all in au) b) NCI isosurfaces for 3C6H6 obtained with reduced density
gradient (RDG) = 05 and blue-green-red color scale ranging from minus002 au lt sign(λ2)ρ(r) lt +002
au c) Graph of RDG versus sign(λ2)ρ for 3C6H6 The regions between the axial H atoms of 3 and
the closest C atoms of benzene are included in the downward peak at negative sign(λ2)ρ
indicating weakly attractive interactions
S15
Figure S3 Experimental 1H NMR spectra (700 MHz) of 3 in CD2Cl2 (bottom) and C6D6 (top)
illustrating the upfield shifts of the signals on going into the aromatic solvent An impurity of
diethyl ether was present in the NMR samples
Figure S4 Experimental 1H 1D gradient selective TOCSY NMR spectra (700 MHz) of 3 in CD2Cl2
(top) irradiated on the Hax signal at 459 ppm and 1H NMR of 3 in CD2Cl2 (bottom) illustrating the
overlap of the Heq protons of 3 with the residual CD2Cl2 solvent signal
S10
Table S6 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
Table S7 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYP-D3def2-TZVP optimised geometries with BSSE corrections included
Table S9 Calculated 1H isotropic shielding tensors for ghostrdquo atoms obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
3C6H6 4C6H6
Hax 118 088
Heq (down) 036 034
Heq (up) --- 028
S14
a) b) c)
Figure S2 Results from topological analysis of the total electron density of 3C6H6 (MP2aug-cc-
pVDZMP2aug-cc-pVDZ level) a) Molecular graph from Atoms-in-Molecules analysis green
bond critical points (BCPs) red ring critical points blue cage critical point Key properties of the
three BCPs connecting 3 to C6H6 = 0007 2 = +0020 ellipticity=+0393 K = -00006 V =
00038 G = +00044 (all in au) b) NCI isosurfaces for 3C6H6 obtained with reduced density
gradient (RDG) = 05 and blue-green-red color scale ranging from minus002 au lt sign(λ2)ρ(r) lt +002
au c) Graph of RDG versus sign(λ2)ρ for 3C6H6 The regions between the axial H atoms of 3 and
the closest C atoms of benzene are included in the downward peak at negative sign(λ2)ρ
indicating weakly attractive interactions
S15
Figure S3 Experimental 1H NMR spectra (700 MHz) of 3 in CD2Cl2 (bottom) and C6D6 (top)
illustrating the upfield shifts of the signals on going into the aromatic solvent An impurity of
diethyl ether was present in the NMR samples
Figure S4 Experimental 1H 1D gradient selective TOCSY NMR spectra (700 MHz) of 3 in CD2Cl2
(top) irradiated on the Hax signal at 459 ppm and 1H NMR of 3 in CD2Cl2 (bottom) illustrating the
overlap of the Heq protons of 3 with the residual CD2Cl2 solvent signal
S11
Table S7 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on B3LYP-D3def2-TZVP optimised geometries with BSSE corrections included
Table S9 Calculated 1H isotropic shielding tensors for ghostrdquo atoms obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
3C6H6 4C6H6
Hax 118 088
Heq (down) 036 034
Heq (up) --- 028
S14
a) b) c)
Figure S2 Results from topological analysis of the total electron density of 3C6H6 (MP2aug-cc-
pVDZMP2aug-cc-pVDZ level) a) Molecular graph from Atoms-in-Molecules analysis green
bond critical points (BCPs) red ring critical points blue cage critical point Key properties of the
three BCPs connecting 3 to C6H6 = 0007 2 = +0020 ellipticity=+0393 K = -00006 V =
00038 G = +00044 (all in au) b) NCI isosurfaces for 3C6H6 obtained with reduced density
gradient (RDG) = 05 and blue-green-red color scale ranging from minus002 au lt sign(λ2)ρ(r) lt +002
au c) Graph of RDG versus sign(λ2)ρ for 3C6H6 The regions between the axial H atoms of 3 and
the closest C atoms of benzene are included in the downward peak at negative sign(λ2)ρ
indicating weakly attractive interactions
S15
Figure S3 Experimental 1H NMR spectra (700 MHz) of 3 in CD2Cl2 (bottom) and C6D6 (top)
illustrating the upfield shifts of the signals on going into the aromatic solvent An impurity of
diethyl ether was present in the NMR samples
Figure S4 Experimental 1H 1D gradient selective TOCSY NMR spectra (700 MHz) of 3 in CD2Cl2
(top) irradiated on the Hax signal at 459 ppm and 1H NMR of 3 in CD2Cl2 (bottom) illustrating the
overlap of the Heq protons of 3 with the residual CD2Cl2 solvent signal
S12
Table S8 Calculated 1H isotropic shielding tensors and chemical shifts obtained at the BHandH6-311+G(2dp) level on MP2aug-cc-pVDZ optimised geometries
Table S9 Calculated 1H isotropic shielding tensors for ghostrdquo atoms obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
3C6H6 4C6H6
Hax 118 088
Heq (down) 036 034
Heq (up) --- 028
S14
a) b) c)
Figure S2 Results from topological analysis of the total electron density of 3C6H6 (MP2aug-cc-
pVDZMP2aug-cc-pVDZ level) a) Molecular graph from Atoms-in-Molecules analysis green
bond critical points (BCPs) red ring critical points blue cage critical point Key properties of the
three BCPs connecting 3 to C6H6 = 0007 2 = +0020 ellipticity=+0393 K = -00006 V =
00038 G = +00044 (all in au) b) NCI isosurfaces for 3C6H6 obtained with reduced density
gradient (RDG) = 05 and blue-green-red color scale ranging from minus002 au lt sign(λ2)ρ(r) lt +002
au c) Graph of RDG versus sign(λ2)ρ for 3C6H6 The regions between the axial H atoms of 3 and
the closest C atoms of benzene are included in the downward peak at negative sign(λ2)ρ
indicating weakly attractive interactions
S15
Figure S3 Experimental 1H NMR spectra (700 MHz) of 3 in CD2Cl2 (bottom) and C6D6 (top)
illustrating the upfield shifts of the signals on going into the aromatic solvent An impurity of
diethyl ether was present in the NMR samples
Figure S4 Experimental 1H 1D gradient selective TOCSY NMR spectra (700 MHz) of 3 in CD2Cl2
(top) irradiated on the Hax signal at 459 ppm and 1H NMR of 3 in CD2Cl2 (bottom) illustrating the
overlap of the Heq protons of 3 with the residual CD2Cl2 solvent signal
S13
Table S9 Calculated 1H isotropic shielding tensors for ghostrdquo atoms obtained at the BHandH6-311+G(2dp) level on B3LYPdef2-TZVP optimised geometries with BSSE corrections included
3C6H6 4C6H6
Hax 118 088
Heq (down) 036 034
Heq (up) --- 028
S14
a) b) c)
Figure S2 Results from topological analysis of the total electron density of 3C6H6 (MP2aug-cc-
pVDZMP2aug-cc-pVDZ level) a) Molecular graph from Atoms-in-Molecules analysis green
bond critical points (BCPs) red ring critical points blue cage critical point Key properties of the
three BCPs connecting 3 to C6H6 = 0007 2 = +0020 ellipticity=+0393 K = -00006 V =
00038 G = +00044 (all in au) b) NCI isosurfaces for 3C6H6 obtained with reduced density
gradient (RDG) = 05 and blue-green-red color scale ranging from minus002 au lt sign(λ2)ρ(r) lt +002
au c) Graph of RDG versus sign(λ2)ρ for 3C6H6 The regions between the axial H atoms of 3 and
the closest C atoms of benzene are included in the downward peak at negative sign(λ2)ρ
indicating weakly attractive interactions
S15
Figure S3 Experimental 1H NMR spectra (700 MHz) of 3 in CD2Cl2 (bottom) and C6D6 (top)
illustrating the upfield shifts of the signals on going into the aromatic solvent An impurity of
diethyl ether was present in the NMR samples
Figure S4 Experimental 1H 1D gradient selective TOCSY NMR spectra (700 MHz) of 3 in CD2Cl2
(top) irradiated on the Hax signal at 459 ppm and 1H NMR of 3 in CD2Cl2 (bottom) illustrating the
overlap of the Heq protons of 3 with the residual CD2Cl2 solvent signal
S14
a) b) c)
Figure S2 Results from topological analysis of the total electron density of 3C6H6 (MP2aug-cc-
pVDZMP2aug-cc-pVDZ level) a) Molecular graph from Atoms-in-Molecules analysis green
bond critical points (BCPs) red ring critical points blue cage critical point Key properties of the
three BCPs connecting 3 to C6H6 = 0007 2 = +0020 ellipticity=+0393 K = -00006 V =
00038 G = +00044 (all in au) b) NCI isosurfaces for 3C6H6 obtained with reduced density
gradient (RDG) = 05 and blue-green-red color scale ranging from minus002 au lt sign(λ2)ρ(r) lt +002
au c) Graph of RDG versus sign(λ2)ρ for 3C6H6 The regions between the axial H atoms of 3 and
the closest C atoms of benzene are included in the downward peak at negative sign(λ2)ρ
indicating weakly attractive interactions
S15
Figure S3 Experimental 1H NMR spectra (700 MHz) of 3 in CD2Cl2 (bottom) and C6D6 (top)
illustrating the upfield shifts of the signals on going into the aromatic solvent An impurity of
diethyl ether was present in the NMR samples
Figure S4 Experimental 1H 1D gradient selective TOCSY NMR spectra (700 MHz) of 3 in CD2Cl2
(top) irradiated on the Hax signal at 459 ppm and 1H NMR of 3 in CD2Cl2 (bottom) illustrating the
overlap of the Heq protons of 3 with the residual CD2Cl2 solvent signal
S15
Figure S3 Experimental 1H NMR spectra (700 MHz) of 3 in CD2Cl2 (bottom) and C6D6 (top)
illustrating the upfield shifts of the signals on going into the aromatic solvent An impurity of
diethyl ether was present in the NMR samples
Figure S4 Experimental 1H 1D gradient selective TOCSY NMR spectra (700 MHz) of 3 in CD2Cl2
(top) irradiated on the Hax signal at 459 ppm and 1H NMR of 3 in CD2Cl2 (bottom) illustrating the
overlap of the Heq protons of 3 with the residual CD2Cl2 solvent signal
