Synthesis, crystal structure, spectroscopy, and magnetism of a mixed valence Co(III)–Co(II)–Co(III) complex stabilized by N-(2-hydroxybenzyl)salicylaldimine

Crystal structure and magnetic properties of a linear tetranuclear CoIIcluster

Polynuclear complexes are an important class of inorganic functional materials and are of interest particularly for their applications in molecular magnets. Multidentate chelating ligands play an important role in the design and syntheses of polynuclear metal clusters. A novel linear tetranuclear CoIIcluster, namely bis{μ3-(E)-2-[(2-oxidobenzylidene)amino]phenolato}bis{μ2-(E)-2-[(2-oxidobenzylidene)amino]phenolato}bis(1,10-phenanthroline)tetracobalt(II), [Co4(C14H11NO2)4(C12H8N2)2], was prepared under solvothermal conditions through a mixed-ligand synthetic strategy. The structure was determined by X-ray single-crystal diffraction and bulk purity was confirmed by powder X-ray diffraction. The complex molecule has a centrosymmetric tetranuclear chain-like structure and the four CoIIions are located in two different coordination environments. The CoIIions at the ends of the chain are in a slightly distorted octahedral geometry, while the two inner CoIIions are in five-coordinate distorted trigonal bipyramidal environments. A magnetic study reveals ferromagnetic CoII...CoIIexchange interactions for the complex.