title: Investigations on the photoreactions of phenothiazine and phenoxazine in presence of 9-cyanoanthracene by using steady state and time resolved spectroscopic techniques.
abstract: By using electrochemical, steady state and time resolved (fluorescence lifetime and transient absorption) spectroscopic techniques, detailed investigations were made to reveal the mechanisms of charge separation or forward electron transfer reactions within the electron donor phenothiazine (PTZH) or phenoxazine (PXZH) and well known electron acceptor 9-cyanoanthracene (CNA). The transient absorption spectra suggest that the charge separated species formed in the excited singlet state resulted from intermolecular photoinduced electron transfer reactions within the donor PTZH (or PXZH) and CNA acceptor relaxes to the corresponding triplet state. Though alternative mechanisms of via formations of contact neutral radical by H-transfer reaction have been proposed but the observed results obtained from the time resolved measurements indicate that the regeneration of ground state reactants is primarily responsible due to direct recombination of triplet contact ion-pair (CIP) or solvent-separated ion-pair (SSIP).
authors.affiliation: Department of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
authors.forename: Munmun
authors.initials: M
authors.lastname: Bardhan
authors.forename: Paulami
authors.initials: P
authors.lastname: Mandal
authors.forename: Wen-Bih
authors.initials: WB
authors.lastname: Tzeng
authors.forename: Tapan
authors.initials: T
authors.lastname: Ganguly
mesh_terms: D000042:Absorption; D000873:Anthracenes / Q000737:chemistry*; D004563:Electrochemistry; D004579:Electron Transport / Q000528:radiation effects; D004583:Electrons; D005453:Fluorescence; D008956:Models, Chemical; D015394:Molecular Structure; D009570:Nitriles / Q000737:chemistry*; D010078:Oxazines / Q000737:chemistry*; D010084:Oxidation-Reduction; D010640:Phenothiazines / Q000737:chemistry*; D055668:Photochemical Processes; D010782:Photolysis; D013050:Spectrometry, Fluorescence; D013057:Spectrum Analysis / Q000379:methods*; D013816:Thermodynamics
chemical_list: C514195:9-cyanoanthracene; D000873:Anthracenes; D009570:Nitriles; D010078:Oxazines; D010640:Phenothiazines; C039203:phenoxazine; C031637:phenothiazine
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