title: Absorption spectrophotometric, fluorescence and theoretical investigations on supramolecular interaction of a designed bisporphyrin with C60 and C70.
abstract: The present article reports the spectroscopic and theoretical investigations on supramolecular interaction between fullerenes (C(60) and C(70)) and a designed bisporphyrin, namely 1, in toluene. Job's method of continuous variation establishes 1:1 stoichiometry of the fullerene/1 complexes. Both absorption spectrophotometric and steady-state fluorescence studies reveal effective and selective interaction between fullerenes and 1 as average binding constants (K) for the C(60)/1 and C(70)/1 complexes are enumerated to be 34,700 and 359,925 dm(3) mol(-1), respectively. Large selectivity ratio in K, i.e., K(C(70))/K(C(60)), indicates that 1 acts as an effective molecular tweezers for C(70) in solution. Time-resolved fluorescence study evokes that the quenching of fluorescence of 1 by fullerenes is of static type in nature. Molecular mechanics calculations in vacuo determine the energies and single projection structures of the supramolecular systems, which provide very good support in favor of strong binding between C(70) and 1.
authors.affiliation: The Department of Chemistry, The University of Burdwan, Golapbag, Burdwan 713104, India.
authors.forename: Debabrata
authors.initials: D
authors.lastname: Pal
authors.forename: Sumanta
authors.initials: S
authors.lastname: Bhattacharya
mesh_terms: D037741:Fullerenes / Q000737:chemistry*; D008958:Models, Molecular; D011166:Porphyrins / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D014050:Toluene / Q000737:chemistry
chemical_list: D037741:Fullerenes; D011166:Porphyrins; D014050:Toluene