Synthesis and Characterisation of Poly(bipyridine)ruthenium Complexes as Building Blocks for Heterosupramolecular Arrays

Abstract

Abstract Poly(bipyridine)ruthenium complexes with carboxylate anchor groups are key components in dye‐sensitised solar cells. In this contribution, an improved microwave‐assisted synthetic procedure is presented for the important building block [RuCl 2 (dcmb) 2 ] (dcmb = 4,4′‐dimethoxycarbonyl‐2,2′‐bipyridine), which results in short reaction times and high purity. The methyl esters are easily deprotected to give free carboxylate functions. In addition, a full structural, spectral and electrochemical characterisation of a series of complexes with the general formula [Ru(dcmb) 3– n (tbbpy) n ](PF 6 ) 2 with n = 0–3 and tbbpy = 4,4′‐di‐ tert ‐butyl‐2,2′‐bipyridine is presented. The location of the lowest‐energy metal‐to‐ligand charge transfer (MLCT) excited state is investigated by resonance Raman spectroscopy for selected complexes. The results obtained indicate that the nature of the excited state that is populated is dependent on the excitation wavelength. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)