Polunin R. Structure, sorption and magnetic properties of porous coordination polymers based on polynuclear complexes of 3d metals

The conditions of porous coordination polymers (PCP) formation by polynuclear complexes binding by bridging ligands of bi- and tripyridine series were determined. It was shown that formation of coordination polymers can occur with destruction of initial polynuclear block or without its change. Reaction of trinuclear complexes with rigid bridging ligands leads to 2D-porous coordination polymers, in a contrast to similar reactions involving labile molecules as bridging ligands, which leads to nonporous compounds, built from 1D-chains. Relationship between structural rearrangements caused by desolvatation and the change of structure caused by temperature decrease was established. Increasing of bridging ligand lengths in PCP leads to higher structural flexibility. Coordination polymers with rigid trigonal bridging ligands possessed rigid microporous crystal structures and were characterized by high sorption capacity (N2, H2). Magnetic properties of initial polynuclear complexes and coordination polymers based on these complexes are similar. In the case when metal ions have similar coordination spheres in solvated and desolvated states, significant differences between magnetic properties of solvated and desolvated samples of PCP were observed at low temperatures (< 100 K). Desolvatation of porous coordination polymer of cobalt(II) leads to significant decrease of magnetic susceptibility in the whole range of measured temperatures (2-100 K). Its resolvatation leads to restoring of magnetic susceptibility values almost to initial level.