Assembly of various degrees of interpenetration of Co-MOFs based on mononuclear or dinuclear cluster units: magnetic properties and gas adsorption.

Three new Co-based MOFs with a nanosized tetradentate pyridine ligand, N,N,N′,N′-tetrakis(4-(4-pyridine)-phenyl) biphenyl-4,4′-diamine (TPPBDA) and carboxylate co-ligands, [Co(TPPBDA)(NO3)2]n·2H2O (1), [Co2(TPPBDA)(bpdc)2 (H2O)]n·2DMA (2) and [Co(TPPBDA)0.5(hfipbb)(H2O)]n·3.5H2O (3) (H2bpdc = biphenyldicarboxylic acid, H2hfipbb = 4,4′-(hexafluoroisopropylidene)bis-(benzoic acid), DMA = N,N-dimethylacetamide) have been synthesized under hydrothermal conditions. For complex 1, a large cavity causes a 4-fold interpenetration of the network, which can be classified as a type IIIa mode of interpenetration. Complex 2 reveals a non-interpenetrating three-dimensional (3D) framework based on the [Co2(μ2-H2O)(CO2)2] unit. Complex 3 is also a 2-fold interpenetrating 3D net based on the [Co2(CO2)2] cluster. These mononuclear or dinuclear cluster units are interconnected by TPPBDA and carboxylate co-ligands, resulting in interesting structural diversities and various degrees of interpenetration.