Synthesis and characterization of a tri-nuclear Co(II) complex with a Bis(catecholate) ligand

A tri-nuclear Co(II) complex of formula [Co3(phen)3(L1)2] [L1 = 2,2′,3,3′-tetrahydroxy-benzaldazine, phen = 1,10-phenanthroline] has been prepared. The complex was characterized by X-ray crystal analysis, ESI-MS and its UV–Vis spectrum. The room temperature value of χmT is 7.50 emu K mol− 1, which is larger than the expected value of 5.58 emu K mol− 1 (for three isolated high spin Co(II) ions). When the temperature is lowered the χmT product continuously decreases down to 5.0 K, which indicates the presence of antiferromagnetic coupling between the CoII ions.