ИСТИНА

Cyclometalated iridium (III) complexes seems to provide a more stable alternative of ruthenium (II) photosensitizers in dye-sensitized solar cells (DSSC). Poor light absorption in the visible spectrum is a still fundamental weakness of these compounds which prevents their application in solar panels. Recently was found that the replacement of traditional 4,4′-dicarboxy-2,2′-bipyridine by asymmetrical aromatic β-diketone bearing a thiophene moiety results in excellent tuning of the redox potentials of the complexes increasing the efficiency of photoanodes twicely [1]. The purpose of this work was to identify correlations between substituents in the β-diketonate ancillary ligand, optical and redox properties of the complexes. A number of new cyclometallated iridium (III) complexes with various aromatic β-diketones and 4,4'-dicarboxy-2,2'-bipyridine as reference series were synthesized, where the most perspective 2-aryl/heteroaryl-1-phenyl-benzimidazoles were used as «antenna» ligands. Herein, we present a joint experimental and theoretical study (X-ray, NMR, MS, UV-Vis, CVA, LS, DFT/ TDDFT) of several series of iridium (III) complexes with 2-arylbenzimidazoles/2-arylphenantroimidazoles and different “anchoring” ligands: