Metal Co(II) and Ni(II) coordination compounds with tetrathiafulvalene carboxylate

Comparing with the TTF-pyridyl metal complexes, very few compounds have been prepared with TTF-carboxylate ligands. We using 8,9-dimethylthio-2,3-dicarboxylate-tetrathiafulvalene sodium salt as starting material prepared two Co(II) and Ni(II) metal complexes, [Co(H2O)6][Co(L)2(DMF)2] and [Ni(H2O)6][Ni(L)2(DMF)2]. X-ray structure analysis has revealed that the metal ion is coordinated by four carboxylate groups from two ligands in the equatorial plane and two DMF molecules in the apical positions. The molecules are assembled by short S⋯S contacts forming a 2D sheet with rectangular grid net. The hexaaquometal cations [Co(H2O)6]2+ reside in the cavities of the 2D network and are fixed by O–H⋯O hydrogen bonds. Cyclic voltammogram and spectra of the ligand are affected when the metal ion coordinated.