Slow magnetic relaxation in mixed-valence coordination polymer, containing Co(III) cluster and Co(II) nodes

Single-molecule magnets in cobalt clusters is much less well known than it is in manganese(II)/(III)/(IV) clusters. To explore new types of cobalt clusters and their potential applications, a new mixed valence coordination polymer ([Co(III)(3)Co(II)(2)(mba)(6)(Hdtba) (H2O)(4)](n,) H(2)dtba=2,2'-dithiodibenzoic acid, H-2 mba = 2-mercaptobenzoic acid) (1) is constructed by employing cobalt chloride hexahydrate and H-2 mba as starting reactants under hydrothermal conditions. Single-crystal XRD studies indicate that 1 consists of a trinuclear cobalt(III)-sulfur cluster moiety and two discrete cobalt(II) nodes, which result in the formation of a covalent three-dimensional complex network. Similarly, the cobalt(III) cluster moiety acts as a building unit in this infinite coordination polymer 1 instead of the discrete and tiara-like clusters previously reported in the literature. Magnetic studies show its slow magnetic relaxation in the absence of an applied dc field, which is characteristic behavior of single-ion magnets, caused by the individual Co(II) ions. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Research on single-molecule magnets in cobalt clusters is less common than in manganese clusters. A new coordination polymer 1 with a three-dimensional complex network structure was constructed, showing slow magnetic relaxation behavior characteristic of single-ion magnets due to Co(II) ions.