Two water-bridged cobalt(ii) chains with isomeric naphthoate spacers: from metamagnetic to single-chain magnetic behaviour

Abstract

The crystal structures and magnetic behaviours of two water-bridged one-dimensional (1D) cobalt(II) chains with different isomeric naphthoate (na⁻) terminals, [Co(H₂O)₃(2-na)₂]_n (1) and {[Co(H₂O)₃(1-na)₂]·2H₂O}_n (2), were reported to investigate the effect of interchain distance on their magnetic properties. Complex 1 with trans-2-na^– blocks and dense interchain separation exhibits a metamagnetic transition from antiferromagnetic ordering to a saturated paramagnetic phase. By contrast, complex 2 possessing cis-arranged 1-na^– spacers and good interchain isolation shows unusual single-chain magnetic behavior under a zero dc field. Thus, completely different interchain packing by isomeric naphthoate ligands governs the ratio of intra- to inter-chain magnetic interactions and further results in different magnetic phenomena, which provide significant magnetostructural information on 1D magnetic systems.