title: Environmental effects on luminescence of meso-tetra-2-chlorophenylporphyrin.
abstract: Effects of solvent polarity on the photophysical behaviour of meso-tetra-2-chlorophenylporphyrin have been studied by means of steady-state absorption and fluorescence, as well as time-resolved fluorescence techniques. A non-mirror symmetric absorption and emission spectra due to vibronic borrowing were obtained. Time-resolved fluorescence study indicated the bi-exponential decay kinetics for both the emission bands, observed in steady-state emission spectra. Such findings implied that there exists two emitting species on the photoinduced conformational excursions of the excited-state equilibrium and also that their relative contributions to emission change with solvent polarity. Monte Carlo conformational search based on force-field molecular mechanics was performed to locate equilibrium conformers in the ground state which enable evaluation of the ground-state barrier energies. This was followed by CIS and ZINDO calculations to explore the excited-state barriers.
authors.affiliation: Department of Chemistry, University of Burdwan, Burdwan 713104, India.
authors.forename: Tandrima
authors.initials: T
authors.lastname: Chaudhuri
authors.forename: Sandip K
authors.initials: SK
authors.lastname: Nayak
authors.forename: Subrata
authors.initials: S
authors.lastname: Chattopadhyay
authors.forename: Manas
authors.initials: M
authors.lastname: Banerjee
mesh_terms: D049449:Luminescence; D008958:Models, Molecular; D008968:Molecular Conformation; D009010:Monte Carlo Method; D010777:Photochemistry; D011166:Porphyrins / Q000737:chemistry*; D011789:Quantum Theory; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D011166:Porphyrins; C551260:tetra-2-chlorophenylporphyrin