UV¨CVis, fluorescence and NMR spectroscopic investigations on inclusion properties of a designed tetrahomocalix[8]arene with fullerenes C₆₀ and C₇₀ in solution

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• 作者：Amal  ; Halder^a ; Suchitra  ; Bhatt^b ; Sandip K.  ; Nayak^b ; Subrata  ; Chattopadhyay^b ; Sumanta  ; Bhattacharya^a ;   ; ^{sum_9974@rediffmail.com}
• 关键词：C₆₀ and C₇₀ ; 1 ; 3 ; 5 ; 7-Tetrahomo-p-tert-butylcalix[8]arene ; UV&ndash ; Vis ; Steady state fluorescence and NMR investigations ; Binding constant
• 刊名：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
• 出版年：2011
• 出版时间：15 December 2011
• 年：2011
• 卷：84
• 期：1
• 页码：25-31
• 全文大小：996 K

文摘

The present article reports the spectroscopic investigations on non-covalent interaction of fullerenes C₆₀ and C₇₀ with a macrocyclic receptor molecule, namely, 1,3,5,7-tetrahomo-p-tert-butylcalix[8]arene (1) in toluene. Jobs method of continuous variation reveals 1:1 stoichiometry for the fullerene complexes of 1. The most fascinating feature of the present study is that 1 binds selectively C₆₀ compared to C₇₀ as obtained from binding constant (K) data of C₆₀-1 (K_C60-1) and C₇₀-1 (K_C70-1) complexes which are enumerated to be 265,000 dm³ mol^? and 63,430 dm³ mol^?, respectively, and selectivity in binding (K_C60-1/K_C70-1) is estimated to be 4.18 as obtained from UV¨CVis study. Steady state fluorescence studies reveal quenching of fluorescence of 1 in presence of fullerenes and the K value of the C₆₀-1 and C₇₀-1 complexes are estimated to be 80,760 and 68,780 dm³ mol^?, respectively, with selectivity in binding (K_C60-1/K_C70-1) ?.18. ¹H NMR analysis provides very good support in favor of strong binding between C₆₀ and 1. The high value of K value for C₆₀-1 complex indicates that 1 forms an inclusion complex with C₆₀.