Weak interchain interaction-dominated magnetic responses in water-extended cobalt(ii)-chains: from magnetic ordering to single-chain magnet

Abstract

Weak intermolecular interactions are of great significance in both the magnetostructural correlations and feasible applications of low-dimensional magnetic materials. However, it is greatly challenging to construct desirable chains with only different interchain aggregations due to the complexity and hard-to-control nature of intermolecular forces and the currently limited number of high-quality magnetic mediators. Herein, two water-extended cobalt(II)-chains are isolated by incorporating the sterically bulky 9-anthracenecarboxylato and 4-quinolinecarboxylato ligands, which together with two previously documented analogues possessing isomeric naphthoate terminals are well-interpreted to tune the magnetic behavior by interchain hydrogen-bonding and C–H⋯π interactions. These carboxylate-functionalized mediators with steric hindrance-tailorable skeletons and embedded hydrogen-bonding sites generate four water-extended cobalt(II)-chains with interchain separations varying from 6.3 Å to 12.7 Å via N/O–H⋯O and C–H⋯π interactions. More importantly, these well-tunable interchain interactions induce metamagnetism, the coexistence of magnetic ordering and single-chain magnet behavior (SCM), as well as only SCM behavior in these antiferromagnetically coupled canting chains. These observations highlight the significance of interchain secondary interactions on molecular magnetism, greatly enriching the magnetostructural relationships of low-dimensional magnetic materials.