New ternary ligands consisting of an N4 bridging ligand and two terpyridines, and their Co(II) and Ni(II) dinuclear complexes. Structure, redox properties, and reaction with acid

作者：Kon Hiroki; Nagata Toshi^*

来源：Dalton Transactions, 2013, 42(16): 5697-5705.

DOI：10.1039/c3dt33011g

Two ternary ligands consisting of two 2,2':6',2 ''-terpyridines and one N4-quadridentate mu(2),eta(2)-bridging ligand were synthesized. The N4 bridge is 1,4-bis(2-pyridyl)phthalazine in ligand 1, and 3,6-bis(2-pyridyl)pyridazine in ligand 2. Two Co(II) dinuclear complexes [(1)Co-2(mu-OH)](3+) and [(2)Co-2(mu-OH)](3+), and one Ni(II) dinuclear complex [(1)Ni-2(mu-Cl)](3+) were obtained. In the crystal structures of [(1)Co-2(mu-OH)](3+) and [(1)Ni-2(mu-Cl)](3+), two pyridine rings are twisted around the pyridine-phthalazine bonds to avoid steric repulsion between the hydrogen atoms. The pyridine rings also showed a significant tilt from the octahedral coordination plane, which causes the large positive shift of the first reduction potentials. Upon the addition of a proton, the cobalt dinuclear complexes can release one cobalt ion selectively, and the dinuclear complexes can be easily restored by the addition of a tertiary amine.

• 出版日期2013