Spin canting and/or metamagnetic behaviours of four isostructural grid-type coordination networks

Abstract

Four isostructural, two-dimensional (2D) grid-type coordination polymers bridged by carboxylate groups, namely [Co(8-qoac)(HCOO)] (1·Co), [Mn(8-qoac)(HCOO)] (1·Mn), [Co(8-qoac)(CH₃COO)] (2·Co) and [Mn(8-qoac)(CH₃COO)] (2·Mn) (8-qoacH = quinoline-8-oxy-acetate acid), were constructed to study the modulation effects of spin carriers and interlayer interactions on the magnetic behaviours. The grid-type layers in these compounds are composed of octahedral metal ions bridged by carboxylate groups of 8-qoac ligands in the anti–anti fashion and formate/acetate in the syn–anti fashion, and these 2D layers are further packed into 3D structures through π–π stacking and hydrogen-bonding interactions. The Mn^II compounds show spin canting antiferromagnetic behaviours, while the Co^II compounds exhibit not only spin canting but also metamagnetic behaviours. Moreover, the critical fields of 1·Co and 2·Co are changed from 200 Oe to 6000 Oe for the stronger interlayer interaction with the second ligand changing from formate to acetate.