Photophysical investigations on supramolecular fullerene/phthalocyanine charge transfer interactions in solution.
Photophysical investigations on supramolecular fullerene/phthalocyanine charge transfer interactions in solution.
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DOI：
10.1016/j.saa.2013.08.107
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发表时间：
2014-01
期刊：
影响因子：
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通讯作者：
A. Ray;H. Pal;S. Bhattacharya
中科院分区：
文献类型：
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作者：
A. Ray;H. Pal;S. Bhattacharya
The photophysical features of non-covalently linked fullerenes C60and C70with a designed free-base phthalocyanine, namely, 2,3,9,10,16,17,23,24-octakis-(octyloxy)-29H,31H-phthalocyanine (1) have been investigated employing various spectroscopic tools like UV–vis absorption spectrophotometry, steady state and time resolved fluorescence along with proton NMR measurements in toluene. The ground state interaction between fullerenes and1is nicely demonstrated with the appearance of well defined charge transfer absorption bands in the visible region of the electronic spectra. Steady state fluorescence experiment reveals efficient quenching of the excited singlet state of1in presence of both C60and C70. The average values of binding constants for the non-covalent complexes of C60and C70with1are determined to be ∼18,150 and ∼32,000 dm3mol−1, respectively. The magnitude ofKsuggests that1preferentially binds C70in comparison to C60although average value of selectivity in binding is measured to be low (∼1.75). Time resolved emission measurements establish photoinduced energy transfer from the excited singlet state of1to fullerene in toluene. Measurements of free energy of electron transfer and free energy of radical ion-pair formation elicit that C70/1complex is stabilized more in comparison to C60/1complex regarding generation of charge-separated state. Proton NMR studies provide very good support in favor of effective ground state complexation between fullerenes and1. Semi empirical theoretical calculations on fullerene/1systems invacuosubstantiate the stronger binding between C70and1in comparison to C60/1system in terms of heat of formation value of the respective complexes, and determine the orientation of bound guest (here C70) towards the plane of1during complexation.
