Synthesis, Photophysical, and Electrochemical Properties of Ru^II Polypyridyl Complexes Bridged with two Tetrapodal Symmetric and one Asymmetric Ligands

Abstract

Two symmetric tetrapodal ligands L 1-2 and one asymmetric tetrapodal ligand L 3 based on 4,5-diazafluoren have been synthesized and characterized. Ligands L 1-2 formed by the condensation of pentaerythrityl tetratosylate with 4,5-diazafluoren-9-oxime and 9-(4-hydroxy)phenylimino-4,5-diazafluorene, respectively. L 3 was prepared by two steps, 9-(4-hydroxy)phenylimino-4,5-diazafluorene reacted with pentaerythrityl tetratosylate affording 1,1',1"-tris[(4,5-diazafluoren-9-ylimino)phenoxymethyl]-1"'-(p-tosyloxymethyl)-methane, * Prof. Dr. F. Cheng Fax: +86-931-8912582 E-Mail: chengfx04@lzu.cn [a] College

Coordination chemistry and applications of versatile 4,5-diazafluorene derivatives

“…9,10 A series of multinuclear Ru(II) complexes supported by multinucleating ligands possessing two or more chelating 4,5diazafluorenyl moieties have been explored. [122][123][124][125][126][127][128][129][130][131][132][133][134][135][136][137][138] The spacers between the coordinating 4,5-diazafluorenyl moieties have been varied substantially to allow for the metal-metal separation, and the degree of intramolecular charge transfer to be finely tuned. In some cases disappointingly the Ru(II) complexes had extremely short excited state lifetimes at room temperature on the order of ∼0.03 ns (e.g., Ru complex of the ditopic ligand with an adamantyl spacer).…”