title: Photophysical investigations on effective and selective complexation of a designed monoporhyrin with C₆₀ and C₇₀ in solution.
abstract: The present paper reports spectroscopic and theoretical insights on ground state complexation of a designed monoporphyrin, 1, with C60 and C70 in toluene. The central interest of the present investigations is the selectivity in binding constant (K) of the fullerene-1 complexes in solution. The ground state interaction between fullerenes and 1 is first evidenced from UV-Vis measurements. Steady state fluorescence experiment reveals efficient quenching of the excited singlet state of 1 in presence of both C60 and C70. Average K values, viz., K(av), for the complexes of C60 and C70 with 1 are determined to be 1620 and 30330 dm(3) mol(-1), respectively. The magnitude of K(av) suggests that 1 preferentially binds C70 in comparison to C60. Time resolved emission measurements establish that C70-1 complex is stabilized much more in comparison to C60-1 system in terms of charge separation process. Ab initio calculations in vacuo substantiate the strong binding between C70 and 1 in terms of heat of formation values of the respective complex, and at the same time, determine the orientation of bound guest (here C70) with the molecular plane of 1.
authors: Department of Chemistry, The University of Burdwan, Golapbag, Burdwan 713 104, India.
authors: B K
authors: BK
authors: Ghosh
authors: Bio-Organic Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
authors: A
authors: A
authors: Bauri
authors: Department of Chemistry, The University of Burdwan, Golapbag, Burdwan 713 104, India. Electronic address: sum_9974@rediffmail.com.
authors: S
authors: S
authors: Bhattacharya
authors: Department of Chemistry, Raja Rammohun Roy Mahavidyalaya, Radhanagore, Hooghly 712 406, India. Electronic address: shrabanti_05@rediffmail.com.
authors: S
authors: S
authors: Banerjee
mesh_terms: D037741:Fullerenes / Q000737:chemistry*; D007700:Kinetics; D055620:Optical Phenomena; D011166:Porphyrins / Q000737:chemistry*; D012996:Solutions; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013997:Time Factors; D014050:Toluene / Q000737:chemistry; D015032:Zinc / Q000737:chemistry
chemical_list: D037741:Fullerenes; D011166:Porphyrins; D012996:Solutions; D014050:Toluene; D015032:Zinc
keywords: Ab initio calculations; Binding constant; Fullerenes; Monoporphyrin; UV–Vis and steady state fluorescence