Nickel(II) and copper(I,II)-based metal-organic frameworks incorporating an extended tris-pyrazolate linker

Solvothermal reactions between the tritopic pyrazole-based ligand 1,3,5-tris((1H-pyrazol-4-yl)phenyl)benzene (H3BTPP) and nickel(ii) perchlorate or copper(ii) nitrate afforded two new metal-organic frameworks, Ni3(BTPP)2·solvent (Ni-BTPP) and CuI4CuII2(OH)2(BTPP)2·solvent (Cu-BTPP). Powder diffraction structure determination methods were employed to determine the crystal and molecular structure of the copper(i,ii) derivative: triangular [Cu3N6(μ3-OH)] nodes are connected to six nearby ones by the pyrazolate ligands, thus constructing flat two-dimensional layers that stack to form slit-like one-dimensional channels. Thermogravimetric analyses highlighted both the thermal stability and the permanent porosity of these two materials. Porosity was confirmed by N2 adsorption at 77 K, yielding Langmuir specific surface areas of 1923(3) m2 g-1 and 874(8) m2 g-1 for Ni-BTPP and Cu-BTPP, respectively. Additionally, Ni-BTPP adsorbed 1.73 mmol g-1 (7.6 wt%) of CO2 at the mild conditions of 298 K and 1 bar.