Two new metal–organic frameworks based on cyclic dodecanuclear copper units

Two new metal–organic frameworks based on cyclic-type dodecanuclear copper units, (Me4N)6[Cu12(OMe)6(pz)6(BTC)6]·18H2O 1 and (Me4N)6[Cu12(OH)6(pz)6(BTC)6]·21H2O 2 (pz = pyrazolate, BTC = 1,3,5-benzenetricarboxylate), have been prepared by the solvothermal reactions of copper salts, Hpz and H3BTC ligands. The cyclic-type Cu12 unit in 1 and 2 is constructed by twelve CuII ions linked together by μ2-OH or μ2-OMe and unidentate carboxylate groups at the inner- and μ-pz and bidentate carboxylate groups at the outer surface of the toroid. In 1 and 2, each Cu12 unit is connected to 12 other units by BTC linkers, leading to 12-connected three-dimensional porous frameworks. The photocatalytic investigations indicate that compounds 1 and 2 exhibit photocatalytic activity for the degradation of RhB.