Absorption spectrophotometric, NMR and theoretical investigations on ground state non-covalent interaction of C₆₀ and C₇₀ with a designed trihomocalix[6]arene in solution

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• 作者：Amal Halder^a ; Kshama Kundu^b ; Sandip K. Nayak^b ; Subrata Chattopadhyay^b ; Sumanta Bhattacharya^a ; ^{sum_9974@rediffmail.com}
• 关键词：C60 and C70 ; Designed 1 ; 3 ; 5-trihomo-calix[6]arene derivative ; UV&ndash ; vis and 1H NMR studies ; PM3 calculations
• 刊名：Spectrochimica Acta Part A ; Molecular and Biomolecular Spectroscopy
• 出版年：2012
• 期刊代码：99_13861425
• 类别：ch
• 出版时间：July, 2012
• 卷：93
• 期：Complete
• 页码：384-389
• 文件大小：478 K

摘要

The present paper reports the spectroscopic investigations on non-covalent interaction of fullerenes C₆₀ and C₇₀ with a designed trihomocalix[6]arene (2) in toluene. UV-vis studies reveal appreciable ground state interaction between fullerenes and 2. Jobs method of continuous variation establishes 1:1 stoichiometry for fullerene-2 complexes. Binding constant (<em>Kem>) data reveals that 2 binds C₇₀ more strongly compared to C₆₀, i.e. <em>Kem>_C60-2 = 47,540 dm³ mol^鈭? and <em>Kem>_C70-2 = 86,360 dm³ mol^鈭?. Proton NMR studies provide very good support in favor of strong binding between C₇₀ and 2. Estimation of solvent reorganization energy (<em>Rem>_S) evokes that C₇₀-2 complex is stabilized more compared to C₆₀-2 complex as <em>Rem>_S(C60-2) = 鈭?.162 eV and <em>Rem>_S(C70-2) = 鈭?.244 eV. Semiempirical calculations at third parametric level of theory <em>in vacuoem> evoke the single projection structures of the fullerene-2 complexes and interpret the stability difference between C₆₀ and C₇₀ complexes of 2 in terms of enthalpies of formation values.