Magnetic properties of cobalt(II/III) complexes with sulfur-scorpionate ligands

A sulfur-scorpionate ligand, hydrotris(1-methylimidazol-2-ylthio)borate, was reacted with CoF3 to afford cobalt complexes, [CoIII(HBmit3)2](HBmit3) (1) and [CoII(HBmit3)2]·4H2O (2) (HBmit3- = hydrotris(1-methylimidazol-2-ylthio)borate). X-ray structural analysis indicated that complexes 1 and 2 have hexacoordinate octahedral and tetracoordinate tetrahedral structures, respectively. Complex 1 is a low-spin cobalt(III) species and complex 2 is a high-spin cobalt(II) (S = 3/2).

Cobalt complexes with tripodal sulfur-ligands, [CoIII(HBmit3)2](HBmit3) and [CoII(HBmit3)2]·4H2O (HBmit3- = hydrotris(1-methylimidazol-2-ylthio)borate) were synthesized. They have hexacoordinate octahedral and tetracoordinate tetrahedral structures, respectively. The cobalt(III) and the cobalt(II) complexes are low-spin and high-spin states (S = 3/2), respectively.Figure optionsDownload as PowerPoint slideHighlights
► The sulfur-scorpionate [HBmit3]− was used to yield mononuclear complexes [CoIII(HBmit3)2]+ and [CoII(HBmit3)2].
► [CoIII(HBmit3)2]+ crystalizes with [HBmit3]− anion in the P21/a space group, providing hexacoordinate centers.
► [CoII(HBmit3)2] crystalizes with crystal water in the P21/n space group, providing tetracoordinate centers.
► [CoIII(HBmit3)2]+ is diamagnetic and [CoII(HBmit3)2] shows spin-only paramagnetism in 2.0–350 K.