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

Abstract

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.