Photo-driven One And Two-electron Processes Of Tetraazatetrapyridopentacene And Substituted Dipyridophenazine Ligands In The Presence Or Absence Of Zinc And Ruthenium Complexation

Abstract

Herein, we report the interaction of light with Zn(II) and Ru(II) adducts of the polypyridal ligands tetraazatetrapyridopentacene (tatpp) and dipyridophenazine (dppz). For examples where Zn(II) is coordinated to tatpp and dppz, we have established a kinetic isotope effect for photo-oxidation of alcohols using both metal-free and metal-bound complexes of tatpp and dppz. The data supports H-atom transfer mechanism in the absence of Zn(II), and a formal "hydride" transfer in the presence of Zn(II).We also report herein the synthesis and characterization of various [Ru(phen)2(dppzX2)]2+ complexes using analytical techniques such as NMR, ESI-MS, CHN, and UV/Vis. We have chemically and electrochemically generated the singly and doubly reduced anions of each complex, and recorded the optical absorbance spectra of each species. Absorption spectra of the photochemically generated anions were compared to the chemically generated spectra, and the data concludes that withdrawing groups can be used to allow photo-driven multi-electron storage in the di-cyano [Ru(phen)2(dppz(CN)2)]2+ complex.Finally, we report the synthesis and characterization of dtatpp and [(Ru(phen)2)4(dtatpp)](PF6)8. These materials are of importance due to their potential to store multiple electrons in orthogonal ð-systems, to form stable bi-radial complexes.