Structure of organic/inorganic interface in assembled materials comprising molecular components.: Crystal structure of the sensitizer bis[(4,4′-carboxy-2,2′-bipyridine)(thiocyanato)]ruthenium(II)

Structural data have been obtained for the photosensitizer bis[(4,4'-carboxy-2,2'-bipyridine)(thiocyanato)]ruthenium(II) (1) via X-ray diffraction analysis. Crystals of 1 are triclinic, a = 11.4663(4) Angstrom, b = 12.5897(5) Angstrom, c = 18.9329(7) Angstrom, alpha = 75.238(2)degrees, beta = 89.611(2)degrees, gamma = 66.446(2)degrees, space group P (1) over bar, Z = 2, refinement to R = 0.0809, R-w = 0.0950 for 4045 observed reflections. Structural models of sensitizer molecules anchoring to the TiO2 anatase surface and models of close-packed sensitizer monolayers with different anchoring types have been built by using experimental geometry of known organic Ti complexes and the X-ray structure of sensitizer 1. On the basis of a simple one-dimensional tight-binding model, it was suggested that possible modifications of TiO2/sensitizer interface could enhance interfacial transparency for injected electrons.