| Abstract |
The novel coordination polymers M(Me(2)BPZ) (M = Co, Zn; H(2)Me(2)BPZ = 3,3 -dimethyl-1H,1 H-4,4 -bipyrazole), M(H(2)Me(2)BPZ) (CH3COO)(2)(H2O)(2) (M = Co, Ni), and Cu(H(2)Me(2)BPZ)(Cl)(2) were isolated along conventional or solvothermal routes. Their crystal structure was unveiled by powder X-ray diffraction (PXRD), while their thermal stability was assessed by coupling thermogravimetric analysis to variable-temperature PXRD. The textural properties of the M(Me2BPZ) (M = Co, Zn) compounds, featuring three-dimensional open frameworks with one-dimensional channels, were assessed by N-2 and CO2 adsorption at 77 and 273 K, respectively, and compared to those of the nonmethylated isostructural counterparts M(BPZ) (M = Co, Zn; H(2)BPZ = 1H,1 H-4,4 -bipyrazole). The positive effect of the methyl groups in CO2 adsorption, suggested by the adsorption energy trend [E-ads(M(Me(2)BPZ)) > E-ads(M(BPZ))] and substantiated by theoretical calculations at the B3LYP-D3 level coupled to topological analyses, is counterbalanced by the higher steric hindrance of Me(2)BPZ(2-) vs BPZ(2-), finally reducing the amount of gas adsorbed by the M(Me(2)BPZ) couple vs the M(BPZ) one. |
