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Amide Coupling Reaction for the Synthesis of Bispyridine-based Ligands and Their Complexation to Platinum as Dinuclear Anticancer Agents
Published on: May 28, 2014
Orientational control of electronic coupling in mixed-valence, binuclear ruthenium(II)-bis(2,2':6',2' '-terpyridine)
Andrew C Benniston1, Anthony Harriman, Peiyi Li
1Molecular Photonics Laboratory, School of Natural Sciences, University of Newcastle, Newcastle upon Tyne, NE1 7RU, U.K.
Abstract:
A series of binuclear ruthenium(II)-bis(2,2':6',2' '-terpyridine) complexes has been prepared around a central biphenylene unit equipped with a strap of variable length. Partial oxidation forms the mixed-valence complex that displays both ligand-to-metal, charge-transfer, and intervalence charge-transfer (IVCT) transitions in the near-IR region. On the basis of Hush theory, the electronic coupling matrix element for interaction between the metal centers decreases with increasing length of the tethering strap. This effect arises because the strap modulates the torsion angle between the phenyl rings and thereby controls the extent of through-bond electronic coupling. The coupling element favors a maximum for planar geometries and a minimum for orthogonal structures, but the full impact of the torsion angle is not realized due to thermal fluctuations.
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