Determination of binding strength for the supramolecular complexation of a designed bisporphyrin with C-60, C-70 and their derivatives employing absorption spectrophotometric, fluorescence and quantum chemical calculations

作者：Mukherjee Sibayan; Bauri Ajay K; Bhattacharya Sumanta^*

来源：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy , 2011, 79(5): 1952-1958.

DOI：10.1016/j.saa.2011.05.099

• C-60
• C-70 and their derivatives
• Designed bisporphyrin
• UV-Vis
• Steady state and time resolved fluorescence investigations
• Binding constant
• MMMF calculations

The present paper reports the synthesis of a designed bisporphyrin (1), and its supramolecular complexes with C-60, C-70 and their derivatives, namely, tert-butyl-(1,2-methanofullerene)-61-carboxylate (2) and [6,6]-phenyl C-70 butyric acid methyl ester (3) in toluene medium. C-60, C-70 and their derivatives undergo ground state non-covalent interaction with 1 is evidenced from absorption spectrophotometric study in which it is observed that the intensity of the Soret absorption band of 1 decreases considerably in presence of C-60, C-70 and their derivatives. Steady state fluorescence studies reveal efficient quenching of fluorescence of 1 in presence of fullerenes. The binding constant (K) values of the fullerene/1 complexes follows the trend: 2/1 < C-60/1 < 3/1 < C-70/1. However, selectivity in K values of the bisporphyrin complexes is found to be higher for fullerene derivatives in comparison to C-60 and C-70. Time resolved emission studies establish relatively long-lived charge separated state for the C-70/1 complex. Molecular mechanics calculations at force field model in vacuo evoke the single projection geometric structures of various fullerene/1 complexes and interpret their stability differences in terms of heat of formation values.

• 出版日期2011-9