Intermolecular interaction energies and magnetic properties of spin-isolated multinuclear CuII complexes

Abstract

Dinuclear CuII complexes with 3,5-dinitrobenzoates and 2,2'-bipyridine (2) or 1,10-phenanthroline (3) were synthesized and characterized. A complete energy framework analysis using the HF/3-21G energy model was performed which found that dispersion forces and C - H⋯O interactions are responsible for the crystal structure features. The magnetic properties of the complexes show a weak magnetic exchange between spins, resulting in low exchange constants of -2.72(1)cm-1 and -1.10(1)cm-1 for complexes (2) and (3), respectively. This results from the low overlap between magnetic orbitals induced by 3,5-dinitrobenzoate bridges and the arrangement of the magnetic orbitals. Consequently, the dinuclear complexes (2) and (3) behave as spin-isolated multinuclear CuII species in contrast to the trinuclear complex with similar ligands.