McConnell I mechanism promotes ferromagnetic interactions between π-stacked Ni(ii)–thiazyl complexes

Abstract

The coordination complex of Ni(hfac)₂ (hfac = 1,1,1,5,5,5-hexafluoroacetylacetonato) and the 4-(benzoxazol-2′-yl)-1,2,3,5-dithiadiazolyl (boaDTDA) neutral radical π-stacks in a one-dimensional “staircase” arrangement. This particular packing aligns regions of α and β spin densities on neighbouring Ni^II(hfac)₂(boaDTDA) molecules. This complex exemplifies a McConnell I type mechanism, giving rise to intermolecular ferromagnetic exchange observed for the first time between metal–thiazyl complexes.