Magnetic and photo-magnetic properties of Co dinuclear complexes

The magnetic and photo-magnetic properties of Co dinuclear compounds were studied. The Co compounds, [{Co(tpa)}2(dhbq)](BF4)3 · 2H2O and [{Co(tpa)}2(dhbq)](ClO4)3 · 2H2O, have the structure [(tpa)CoIII-LS–(μ-dhbq)3−–CoIII-LS(tpa)]3− (where LS, H2dhbq, tpa denote low-spin, 2,5-di-hydroxy-1,4-benzoquinone and tris(2-pyridylmethyl)amine, respectively) at room temperature. On heating, these compounds exhibit valence-tautomeric inter-conversion; [(tpa)CoIII-LS–(μ-dhbq)3−–CoIII-LS(tpa)]3− ⇆ [(tpa)CoII-HS–(μ-dhbq)2−–CoIII-LS(tpa)]3− (where HS denotes high-spin). Furthermore, both of these compounds exhibit photo-induced valence tautomerism at low temperature (<60 K). These results show that the electronic structures of these complexes can be controlled by modifying the counter anions.

Graphical abstractThermally- and photo-induced valence tautomerism in Co dinuclear complexes was studied. It was found that the valence tautomeric behaviors can be tuned by modifying counter anions.Figure optionsDownload full-size imageDownload as PowerPoint slide