Effect of the Addition of a Fused Donor-Acceptor Ligand on a Ru(II) Complex: Synthesis, Characterization, and Photoinduced Electron Transfer Reactions of Ru(TTF-dppz)(2)(Aqphen) (2+)

The synthesis and the photophysical properties of the complex [Ru(TTF-dppz)(2)(Aqphen)](2+) (TTF = tetrathiafulvalene, dppz = dipyrido-[3,2-a:2',3'-c]phenazine, Aqphen = anthraquinone fused to phenanthroline via a pyrazine bridge) are described. In this molecular triad excitation into the metal ligand charge transfer bands results in the creation of a long-lived charge separated state with TTF acting as electron donor and anthraquinone as terminal acceptor. The lifetime of the charge-separated state is 400 ns in dichloromethane at room temperature. A mechanism for the charge separation involving an intermediate charge-separated state is proposed based on transient absorption spectroscopy.

Synthesis and reactions of two stereoisomeric 4.5.5.5 fenestranes with bridgehead substituents

The [4.5.5.5]fenestranes 2 and 3 with two different functionalities were prepared in seven steps with overall yields of 5% and 10%, respectively. For introduction of a bridgehead double bond the removal of the tertiary hydroxy group was investigated in the two stereoisomeric hydroxyketones 12 and 15. Whereas the dehydration readily occurred in 12, a ring opening reaction was observed for 15. (C) 2011 Elsevier Ltd. All rights reserved.