Packing of ruthenium sensitizer molecules on mostly exposed faces of nanocrystalline TiO2: crystal structure of (NBu4+)2[Ru(H2tctterpy)(NCS)3]2−·0.5 DMSO

An X‐ray crystal study of the new ‘black dye’ sensitizer tri(thiocyanato)(4,4′,4″‐tricarboxy‐2,2′:6′,2″‐terpyridine)ruthenium(II) is reported. In the crystal, strong hydrogen bonds form chains of ruthenium complex dianions with the O···O distances of 2.48–2.54 Å. From the molecular geometry of the dianions, structural models of their close packing on the (101) and (001) crystal surfaces of TiO2 (anatase) have been built. The maximum possible density of molecular packing noticeably exceeds the experimental value. The hydrogen bonding between the anions in monolayers, located on the TiO2 surface, is discussed. Copyright © 2002 John Wiley & Sons, Ltd.