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

Abstract

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. These groups also allow the complexes to anchor to the surface of TiO2 nanoparticles, as evidenced by colouration of the TiO2 and FT-IR spectroscopy. The ability of these complexes to capture a significant fraction of sunlight and to adhere to TiO2 surfaces renders them viable dyes for photochemical devices such as dye sensitised solar cells.

4,4′-Difluoro-4-bora-3a,4a-diaza-s-indacenes (BODIPYs) as components of novel light active materials

“…Although dipyrrinemetal complexes have not yet been incorporated into DSSCs, their binding to titanium dioxide has recently been studied. 78 Rhodium, palladium and ruthenium complexes of 5-(4-carboxy)phenyl-dipyrromethene were synthesised and were shown to bind to titanium dioxide and their absorption profiles were measured. However, no photocurrent-generation experiments were reported for these compounds.…”

New aspects in bis and tris(dipyrrinato)metal complexes: bright luminescence, self-assembled nanoarchitectures, and materials applications

“…36 Several supramolecular and coordination polymeric systems show luminescence, as will be discussed in Section 3. Mono(dipyrrinato)metal complexes containing Sn(I), 37 Cu(I), 38 49 and Mg(II) 50,51 centers also exhibited luminescence, the details of which are discussed in a comprehensive review.…”

Heteroleptic half-sandwich Ru(II), Rh(III) and Ir(III) complexes based on 5-ferrocenyldipyrromethene

“…Considerable current attention has been paid towards the synthesis and characterization of complexes based on mesosubstituted dipyrrin ligands owing to their ease of synthesis, rich optical properties and tendency to form stable complexes with a variety of metal ions [1,2]. Presence of two pyrrolic nitrogen donors in planar dipyrrin core and functionalized meso-substituents enables the dipyrrins to display wide applications in coordination chemistry [1].…”