Gas Adsorption of Two Dimensional Super Flexible and Three Dimensional Biporous Coordination Polymers with Identical
Framework CompositionA, Kondo,a, f H, Noguchi,b H, Kajiro,c L. Carlucci,d D. M. Proserpio,d G. Ciani,d Y. Hattori,e F. Okino,e T. Ohba,b K. Kaneko,b H. Kanohb
a: Collaborative Innovation Center for Nanotech FIBER (nanoFIC), Shinshu University, Ueda, Japan, b: Graduate School of Science, Chiba University, Yayoi, Inage, Chiba, Japan, c: Nippon Steel Corporation, Shintomi, Futtsu, Chiba, Japan, d: Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Universita` di Milano, Via G. Venezian 21, Italy, e:
Department of Chemistry, Faculty of Textile Science and Technology, Shinshu University, Ueda, JapanPresent address f: Tokyo University of Agricculture and Technology, Graduate School of Engineering, Department of Applied Chemistry, Tokyo, Japan.
E-mail: [email protected]
0.19(6.2 mmol g−1)
(61%)
0.095 (3.8 mmol g−1)
(31%)
0.27 (8.0 mmol g−1)
(87%)
3D PCP(mL g−1)
0.35 (12 mmol g−1)
(250%)
0.23(8.3 mmol g−1)
(164%)
0.27(7.9 mmol g−1)
(193%)
2D PCP(mL g−1)
ArCO2N2
ABSTRACTABSTRACTSelective synthetic routes of [Cu(bpy)2(OTf)2]n (bpy = 4,4΄-bipyridine, OTf = trifluoromethanesulfonate) with two and three dimensionalities by choosing each inherent different solvent-
solution system were established. They have a quite similar local coordination structure around a Cu(II) ion, leading the 2D and 3D building-up structures with different connectivity. Although the two kinds of porous coordination polymers (PCPs) have framework flexibility, the 2D PCP (ELM-12)[1,2] is more flexible than the 3D PCP[3], giving rise to different framework flexibility-associated gas adsorption behaviors. All adsorption isotherms for N2, CO2, and Ar on the 3D PCP are of type I, whereas the 2D PCP has stepwise gas adsorption isotherms for CH4 and water in addition to these gases. The 3D PCP having hydrophilic and hydrophobic pores shows the size selective and quadrupole-surface electrical field interaction dependent adsorption[4]. The 2D PCP can accommodate remarkably greater amount of gas molecules than that corresponding to the inherent void volume through the framework structural change. In alcohol adsorption isotherms, however, the 2D PCP changes its framework structure through the guest accommodation, leading to no stepwise adsorption isotherms The structural diversity of the 2D PCP stems from the breathing phenomenon[5,6] and expansion/shrinkage modulation[7-9].
REFERENCES[1] Kondo, A.; Noguchi, H.; Carlucci, L.; Proserpio, D. M.; Ciani, G.; Kajiro, H.; Ohba, T.; Kanoh, H.; Kaneko, K. J. Am. Chem. Soc. 2007, 129, 12362−12363.[2] A. Kondo, A. Chinen, H. Kajiro, T. Nakagawa, K. Kato, M. Takata, Y. Hattori, F. Okino, T. Ohba, K. Kaneko, H. Kanoh, Chem. Eur. J., 2009, 31, 7549-7553. [3] Carlucci, L.; Cozzi, N.; Ciani, G.; Moret, M.; Proserpio, D. M.; Rizzato, S. Chem. Commun. 2002, 1354-1355.
CONCLUSIONCONCLUSION· The synthesis of 2D and 3D structures of [Cu(bpy)2(OTf)2] can be controlled by using different kinds of alcohol as interlayer solvent.· The 2D PCP (ELM-12) shows stepwise adsorption isotherms due to not only the expansion / shrinkage structural transformation but also breathing phenomenon. The micropore filling is not indispensable for the structural change, which can occur without definite steps in adsorption isotherms. · The 3D PCP having hydrophilic and hydrophobic pores shows the size selective and quadrupole-surface electrical field interaction dependent adsorption and has potential to accommodate different kinds of molecules in the inherently different pores separately.
[5] C. Serre, F. Millange, C. Thouvenot, M. Noguès, G. Marsolier, D. Louër, G. Férey, J. Am. Chem. Soc., 2002, 124, 13519-13526.[6] S. Bourrelly, P. L. Llewellyn, C. Serre, F. Millange, T. Loiseau, G. Férey, J. Am. Chem. Soc., 2005, 127, 13519-13521.[7] L. Di, K. Kaneko, Chem. Phys. Lett. 2001, 335, 50-56.[8] Noguchi, H.; Kondoh, A.; Kanoh, H.; Kajiro, H.; Kaneko, K. J. Phys. Chem. B 2005, 109, 13851−13853.[9] Kondo, A.; Noguchi, H.; Ohnishi, S.; Kajiro, H.; Tohdoh, A.; Hattori, Y.; Xu, W.-C.; Tanaka, H.; Kanoh, H.; Kaneko, K. Nano Lett. 2006, 6, 2581−2584
Expansion / shrinkage modulationExpansion / shrinkage modulation
ExpansionExpansion
ShrinkageShrinkage
As synthesized
0.140.25mL g-1
% 1831Void volume
5.65, 6.94 6.10Offset (Å)5.86, 6.73 7.16 Interlayer distance (Å)Guest freeAs synthesizedCrystal state
Structural parameters in the layered structuresStructural parameters in the layered structures
Guest free
High pressure HHigh pressure H22, CH, CH44 and COand CO22 adsorption isotherms adsorption isotherms on 2D PCP (ELMon 2D PCP (ELM--12)12)
Cu(OTf)Cu(OTf)22 (30.0 (30.0 mMmM, 10.0 , 10.0 mLmL) aqueous solution) aqueous solution
bpy bpy ethanolicethanolic solution (60.0 solution (60.0 mMmM, 10.0 , 10.0 mLmL))Interlayer solvent ( 1.0 Interlayer solvent ( 1.0 mLmL))
Dark blue crystalsDark blue crystals Dark blue crystalsDark blue crystals
methanol, ethanol,methanol, ethanol,11--propanol, 1propanol, 1--butanolbutanol 11--hexanol, 1hexanol, 1--octanoloctanol
The 2D crystalThe 2D crystal The 3D crystalThe 3D crystal
c
b
Interlayer solventInterlayer solvent
2D crystal structure2D crystal structure
a
b
Hydrophobic
Hydrophilic
37.70.31
Total pore volume
24.713.0%0.200.11mL g-1Pore volume
HydrophobicHydrophilic
c
b
3D crystal structure3D crystal structure
Adsorption isotherms of NAdsorption isotherms of N22, CO, CO22, and, and ArAr on 2D and 3D PCPson 2D and 3D PCPs3D PCP3D PCP2D PCP (ELM2D PCP (ELM--12)12)
Ar : 0.376 nmN2 : 0.310 nm CO2 : 0.340 nm
Hydrophilic pore0.33 ± 0.02 nm
Hydrophobic pore> 0.45 nm
Selective adsorption of 3D PCP Selective adsorption of 3D PCP
Total pore volume (mL g−1) 0.31Hydrophilic pore Volume (mL g−1) 0.11Hydrophobic pore volume (mL g−1) 0.20
Adsorbed volume (mL g−1)
N2 0.27Ar 0.19
CO2 0.095
In situ IR spectra through COIn situ IR spectra through CO22 adsorptionadsorption
Pore and adsorbed volume Pore and adsorbed volume
Adsorbed amount of each gases on 2D and 3D PCP
Used density for calculation of adsorbed amount in ml/g unit. N2: 0.808 g/mL, CO2, 1.565 g/mL, Ar: 1.395 g/mL.Each percentage shows the percentage of adsorbed amount against the void volumes of the guest free states.
0
5
10
15
20
25
30
0 1 2 3 4 5 6
Surf
ace
exce
ss m
ass o
f CH
4 (mg/
g)
Fugacity (MPa)0
20
40
60
80
100
120
140
160
0 0.5 1 1.5 2 2.5
Suef
ace
exce
ss m
ass o
f CO
2 (mg/
g)
Fugacity (MPa)
Synchrotron XRD patterns of 2D PCP without guest, adsorbing alcohols and water at room temperature
1100120013001400150016001700
Inte
nsity
/ a.
u.
Wavenumber / cm-1
Local structure Local structure around around Cu(IICu(II) ion) ion
Synthesis of 2D and 3D crystals [Cu(bpy)Synthesis of 2D and 3D crystals [Cu(bpy)22(OTf)(OTf)22]]
bpybpy bendingbendingat 196 Kat 196 K
νas of SO3 in OTf
11201140116011801200
Abs
orba
nce
/ a.u
.
Wavenumber / cm-1
1172 cm-1
1182 cm-1
NN22: : Adsorption in both pore (hydrophilic and hydrophobic)Adsorption in both pore (hydrophilic and hydrophobic)ArAr: : Size selective adsorption into hydrophobic poreSize selective adsorption into hydrophobic poreCOCO22: : QuadrupoleQuadrupole--surface electrical field interaction surface electrical field interaction (between CO(between CO22 and and OTfOTf) dependent adsorption into ) dependent adsorption into hydrophilic porehydrophilic pore
13.3 13.3 kPakPa
0 0 kPakPa
CH4 adsorption at 258 K CO2 adsorption at 273 K
Interaction between COInteraction between CO22 molecules and molecules and OTfOTf anionsanions
Carbon dioxide adsorption in hydrophilic pore Carbon dioxide adsorption in hydrophilic pore
Isosbesticpoint
Crystallographic pore volume Crystallographic pore volume 0
2
4
6
8
10
12
0 1 2 3 4 5 6
Surf
ace
exce
ss m
ass o
f H2 (m
g/g)
Fugacity (MPa)
H2 adsorption at 77 K
0
50
100
150
200
250
0 0.2 0.4 0.6 0.8 1
Ads
orbe
d am
ount
s (m
g/g)
P/P0
● MeOH● EtOH● 1-PrOH● Water
+ guest
- guestExpansion
+ guest
- guest
Dotted line: Length of diagonal length
Arrow: Interlayer distance
Distortion of 2D grid
Expansion/shrinkage
Alcohol adsorption isotherms
No definite folding point
Structural change can occur without definite folding points in isotherms.
at room temp.
Folding pointFolding pointExtend DR analysis of H2
adsorption isotherm at 77 K
Estimated saturated adsorption amount: 7 mg/g
Experimental maximum adsorption amount
~10 mg/g
Type I isotherms
Almost no micropore filling
Slight hysteresisLarge hysteresis
Hydrophobic nature
aa
bb
