Chromophoric dipyrrin complexes capable of binding to TiO2: synthesis, structure and spectroscopy.

The synthesis, characterisation, and TiO2 binding studies of a series of chromophoric complexes of 5-(4-carboxyphenyl)-4,6-dipyrrin (L(b)) are presented. The synthesis of [Ru(bipy)(L(b))2] (bipy = 2,2-bipyridine), [Rh(L(b))3], and [Pd(L(b))2] was achieved by initial coordination of 5-(4-methoxycarbonylphenyl)-4,6-dipyrrin (L(a)) followed by hydrolysis of the ester group. The carboxyl groups that are located on the peripheries of these complexes are able to engage in intermolecular hydrogen bonding interactions in the solid state, as revealed by X-ray crystallography.

Heteroleptic dipyrrin/bipyridine complexes of ruthenium(II).

The synthesis and characterization of a series of heteroleptic dipyrrinato/2,2'-bipyridine complexes of ruthenium(II) are reported. Spectroscopic analysis, including resonance Raman, indicates that the complexes are only weakly emissive and that the dipyrrin and Ru --> bipyridine (metal-to-ligand charge transfer) chromophores are uncoupled.