Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2011-01-01

Photophysical insights into supramolecular interaction of a designed bisporphyrin with fullerenes C60 and C70.

Debabrata Pal, Mina Furukawa, Naoki Komatsu, Hidemitsu Uno, Sumanta Bhattacharya

Index: Spectrochim. Acta. A. Mol. Biomol. Spectrosc. 78(1) , 185-90, (2011)

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Abstract

The present paper reports the photophysical investigations of a designed bisporphyrin (1), and its supramolecular complexes with C60 and C70 in toluene medium. UV-vis studies reveal appreciable ground state interaction between fullerenes and 1. The stoichiometry of the fullerene complexes of 1 is found to be 1:1. Steady state fluorescence studies elicit quenching of fluorescence of 1 in the presence of fullerenes. The binding constants of the C60/1 and C70/1 complexes are estimated to be 3760 and 31,222.5 dm3 mol(-1), respectively. Time resolved emission studies establish relatively long-lived charge separated state for the C70/1 complex. Molecular mechanics calculations in vacuo evoke the stereoscopic structures of the fullerene/1 complexes and interpret the stability difference between C60 and C70 complexes of 1 in terms of heat of formation values.Copyright © 2010 Elsevier B.V. All rights reserved.