Abstract
The photoionization of metalloporphyrins (MTPP) adsorbed in 40 A pore silica gel is studied with visible light irradiation at room temperature and 77 K. MTPPs, such as zinc(II) meso-tetraphenylporphyrin (ZnTPP), nickel(II) meso-tetraphenylporphyrin (NiTPP), and copper(II) meso-tetraphenylporphyrin (CuTPP) are used to study the effects of the central metal ions on the efficiency of MTPP photoionization in silica gel in comparison with metal-free meso-tetraphenylporphyrin (H2TPP). Porphyrin π-cation radicals are generated in silica gel by photoirradiation and are characterized by electron paramagnetic resonance (EPR) and diffuse reflectance (DR) UV–VIS spectroscopy. The photoionization efficiency of such porphyrins decreases in the order ZnTPP > H2TPP > NiTPP. For CuTPP/silica gel, no CuTPP+ radical is detected by EPR or by DR UV–VIS spectroscopy. Upon photoirradiation, porphyrin π-cation radicals ZnIITPP+ and NiIITPP+ are produced by oxidation of the porphyrin ring instead of the central metal ion. Thus, (NiIIITPP)+ is not observed in NiTPP/silica gel by photoirradiation.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of the Chemical Society, Faraday Transactions
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
