title: Interaction between certain porphyrins and CdS colloids: a steady state and time resolved fluorescence quenching study.
abstract: The interaction between porphyrins namely, meso-tetrakis (4-methoxyphenyl)porphyrin (TMeOPP), protoporphyrin IX (PPIX) and Zinc(II) meso-tetraphenylporphyrin (ZnTPP) with colloidal CdS has been studied by using steady state and time resolved fluorescence quenching measurements. The porphyrins adsorbed on the surface of colloidal CdS due to electrostatic interaction. This adsorption leads to changes in the absorption spectra related to the complex formation. The apparent association constant (Kapp) was in the order of 4.34-5.58 x 10(5) M(-1) from the effect of colloidal CdS on the absorption spectra and 0.64-1.6 x 10(5) M(-1) from fluorescence quenching data. Quenching is attributable mainly to static mechanism through ground state complex formation as confirmed by lifetime measurements.
authors.affiliation: School of Chemistry, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu, India.
authors.forename: M Asha
authors.initials: MA
authors.lastname: Jhonsi
authors.forename: A
authors.initials: A
authors.lastname: Kathiravan
authors.forename: R
authors.initials: R
authors.lastname: Renganathan
mesh_terms: D000327:Adsorption; D019187:Cadmium Compounds / Q000737:chemistry*; D003102:Colloids; D005453:Fluorescence; D007700:Kinetics; D053768:Metal Nanoparticles / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D011166:Porphyrins / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods*; D055672:Static Electricity; D013440:Sulfides / Q000737:chemistry*; D013997:Time Factors
chemical_list: D019187:Cadmium Compounds; D003102:Colloids; D011166:Porphyrins; D013440:Sulfides; C034939:cadmium sulfide