Photo-induced intramolecular electron transfer in phenoxazine-phthalocyanine donor-acceptor systems

Donor-Acceptor (D-A) systems based on phenoxazine - phthalocyanine (PXZ-Pc) and phenoxazine - zinc phthalocyanine (PXZ-ZnPc) have been designed and synthesized. Both D-A systems are characterized using various spectroscopic and electrochemical techniques including in-situ methods. Optical absorption studies suggest that both Soret and Q bands of these D-A systems are hypsochromically and bathochromically shifted, when compared to its individual constituents. The study supported by theoretical calculations shows clearly that there exists a negligible electronic communication in the ground state between donor phenoxazine and acceptor phthalocyanine. However, attractively, both D-A systems exhibit noteworthy fluorescence emission quenching (90-99%) of the phthalocyanine emission compared to its reference compounds. The fluorescence emission quenching featured at the excited-state intramolecular photoinduced electron transfer from ground state of phenoxazine to the excited state of phthalocyaine/zinc phthalocyanine. The rates of electron-transfer (k(ET)) of these D-A systems are found in the range of 5.7 x 10(8) to 2.8 x 10(9) s(-1) and are according to solvent polarity.

Automated summary

Donor-Acceptor systems based on phenoxazine - phthalocyanine and phenoxazine - zinc phthalocyanine were designed and synthesized. The study characterized the systems using spectroscopic and electrochemical techniques, supported by theoretical calculations. The systems exhibited significant fluorescence emission quenching.