Effects of a Central Atom and Peripheral Substituents on Photoinduced Electron Transfer in the Phthalocyanine-Fullerene Donor-Acceptor Solution-Processable Dyads

For understanding the physical chemistry behind improving photoelectrochemical charge separation parameters and providing solution-processability, multiple peripheral substitution by 3,5-di-tert-butylphenoxy groups in design of donor-acceptor phthalocyanine-fullerene systems with two different central atoms was realized. Their UV-vis/IR/H-1 NMR/fluorescence/femtosecond transient absorption spectra, self-assembly thermodynamics, electrochemistry, and DFT-calculated (the B3LYP+D3BJ/6-31G level of theory) geometric/electronic structures were obtained and analyzed. The self-assembly in (octakis(3,5-di-tert-butylphenoxy)phthalocyaninato)cobalt(II)/manganese(III) acetate -1'-N-methy1-2'-(1H-imidazol-1-y1)-phenylpyrrolidino[3',4':1,2][60]fullerene-toluene system, the mechanism of which depends on a central metal atom, results in the formation of phthalocyanine-fullerene donor-acceptor dyads with relatively high bonding constants and an efficient property of photoinduced charge separation. Effects of replacement of the central metal atom and functional substitution in ground and excited state interactions were discussed. The metal phthalocyanine-substituted fullerene radical ion-pairs formation proved by comparison of transient and spectroelectrochemical results suggest the potential use of functionalized phthalocyanine-fullerene dyads as a functional material for building optoelectronic devices.