title: Spectroscopic and theoretical insights on effective and selective non-covalent binding between fullerenes (C60 and C70) and a designed diporphyrin in solution.
abstract: The present work reports the photophysical insights behind effective non-covalent interaction between a designed diporphyrin (1) and fullerenes C60 and C70 in toluene. Ground state electronic interaction between fullerenes and 1 is evidenced from UV-Vis measurements in which it is observed that the intensity of the Soret absorption band of 1 is decreased considerably in presence of both C60 and C70. Steady state fluorescence studies reveal efficient quenching of the fluorescence intensity of 1 in presence of fullerenes. Evaluation of binding constants for the fullerene/1 systems evoke that 1 may be employed as an efficient molecular tweezers for C70 in toluene as selectivity in binding is determined to be ∼9.4. Time resolved emission studies establish relatively long-lived charge separated state for the C70/1 system in comparison to C60/1. Molecular mechanics calculations by force field method in vacuo interpret well regarding stability difference between C60 and C70 complexes of 1 and give formidable support in favor of side-on orientation motif of C70 towards the plane of 1 during non-covalent complexation process.
authors.affiliation: Department of Chemistry, The University of Burdwan, Golapbag, Burdwan 713 104, India.
authors.forename: Sibayan
authors.initials: S
authors.lastname: Mukherjee
authors.forename: Ajoy K
authors.initials: AK
authors.lastname: Bauri
authors.forename: Sumanta
authors.initials: S
authors.lastname: Bhattacharya
mesh_terms: D037741:Fullerenes / Q000737:chemistry*; D007700:Kinetics; D011166:Porphyrins / Q000737:chemistry*; D012996:Solutions; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013997:Time Factors
chemical_list: D037741:Fullerenes; D011166:Porphyrins; D012996:Solutions; C069836:fullerene C70; C069837:fullerene C60
keywords: Binding constant; C(60) and C(70); Diporphyrin; MMMF calculations; UV–Vis, steady state and time resolved fluorescence measurements