Magnetic spin exchange interactions between several metal centres in paramagnetic complexes with new polynucleating bridging ligands

Abstract

The polynucleating bridging ligands L¹ and H₃L² were simply prepared via a Heck coupling of 4-vinylpyridine or 4-methoxystyrene with 1,3,5-tribromobenzene; in the trinuclear complexes of L¹ and L² with a paramagnetic {Mo(NO){BH(C₃HN₂Me₂-3,5)₃}Cl} moiety [BH(C₃HN₂Me₂-3,5)₃= tris(3,5-dimethylpyrazol-1-yl) hydroborate] at each binding site the EPR spectra demonstrate that all three unpaired electrons are in ‘fast exchange’ between all three metal centres