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A series of new RuII complexes has been synthesised, with different azo ligands as additional chromophore. The dyes are all intensely colored due to MLCT and ILCT transitions in the visible region. The photophysical study of the dyes, carried out by UV/Vis absorption and emission spectroscopy, showed unusual features such as intense solvatochromism and solvent-dependent extinction coefficients. The energies of these excited states have been tuned by changing the electron density across the series of azo ligands, and this results in different contributions from each charge transfer process for the different complexes and consequently, different emission behavior. The detailed behaviour of these dyes was further studied and interpreted through electrochemical, structural and computational techniques. The dyes do not work well as sensitisers for DSSCs and this is investigated by emission spectroscopy on TiO2 and ZrO2 films, suggesting poor charge injection to TiO2. [ABSTRACT FROM AUTHOR]

The sulfonated bipyridine derivative disodium 6,6′-bis(sulfonatomethyl)-2,2′-bipyridine [Na2(smbipy)] was synthesized, and its complexation behaviour towards divalent 3d metals in aqueous solution was explored. The complexes of late 3d metals [M(smbipy)(H2O)2] ·H2O (M = Co, Ni, Zn) and [Cu(smbipy)(H2O)] are sparingly soluble in water, and their crystal structures show fourfold equatorial coordination (κ4 N, N′, O, O′) of the smbipy ligand. Ammonia-rich solutions of the NiII and CuII aqua complexes yield the decomplexation products [Ni(NH3)6](smbipy), [Ni(NH3)5(H2O)](smbipy) and [Cu(NH3)4](smbipy) ·2H2O. Buffered solutions with a reduced ammonia content lead to [Ni(smbipy)(NH3)2] and [Cu(smbipy)(NH3)3] ·2H2O, and the latter shows twofold coordination of the smbipy ligand through the nitrogen atoms only (κ2 N, N′). When nearly quantitative amounts of ammonia are applied, two closely related complexes with the core motif [(smbipy)Cu(μ-OH)2Cu] form. Crystal structures of all complexes were obtained, and their features are discussed. [ABSTRACT FROM AUTHOR]

Invited for the cover of this issue are the groups of Jianzhang Zhao from Dalian University of Technology, China, and Mustafa Hayvali from Ankara University, Turkey. The cover image shows switching of the 3MLCT states of a ruthenium(II) complex by rhodamine. [ABSTRACT FROM AUTHOR]