Absorption spectrophotometric, fluorescence, transient absorption and quantum chemical investigations on fullerene/phthalocyanine supramolecular complexes

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 78; no. 5; pp. 1364 - 1375
• Main Authors: Ray, Anamika, Santhosh, Kotni, Bhattacharya, Sumanta
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 01.05.2011
• Subjects: Absorption; DFT calculations; Electricity; Fullerenes; Fullerenes - chemistry; Indoles - chemistry; Kinetics; Models, Chemical; Photolysis; Phthalocyanine; Quantum Theory; Solvents - chemistry; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Steady state and time resolved fluorescence measurements; Thermodynamics; Time Factors; Transient absorption study; UV–vis; UV–vis; Fullerenes; Phthalocyanine; Transient absorption study; Steady state and time resolved fluorescence measurements; DFT calculations
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2011.01.011

[Display omitted] ► The present article introduces a newly designed Pc-derivative, namely, 2,9,16,23-tetra-tert-butyl-29H,31H-Pc ( 1), which is a very unique molecule in terms of its important photophysical features. ► The monophthalocyanine, 1, is unable to serve as an effective and selective molecular tweezers for C 70. ► Binding of C 60 and C 70 in the cleft of 1 is clearly demonstrated by the stereoscopic structures generated by DFT calculations. ► The mechanism of energy transfer phenomenon from 1 to C 60 and C 70 is nicely demonstrated by the transient absorption study in our present investigations. ► The results reported in the present investigations would provide a viable environment to see the various interactive processes involved in fullerene/phthalocyanine systems at ground and excited states. The present paper reports the photophysical investigations on supramolecular interaction of a phthalocyanine derivative, namely, 2,9,16,23-tetra-tert-butyl-29H,31H-Pc ( 1) with C 60 and C 70 in toluene. The binding constants of the C 60 and C 70 complexes of 1 are estimated to be 27,360 and 25,205 dm 3, respectively. Transient absorption measurements in the visible region establishes that energy transfer from C 60 * T (and C 70 * T ) to 1 occurs predominantly in toluene which is subsequently confirmed by the consecutive appearance of the triplet states of 1. Quantum chemical calculations at DFT level of theory explore the geometry and electronic structure of the supramolecules and testify the significant redistribution of charge between fullerenes and 1.