Structure and Electronic Spectra of Purine–Methyl Viologen Charge Transfer Complexes

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• 作者：Almaz S. Jalilov ; Sameer Patwardhan ; Arunoday Singh ; Tomekia Simeon ; Amy A. Sarjeant ; George C. Schatz ; Frederick D. Lewis
• 刊名：Journal of Physical Chemistry B
• 出版年：2014
• 出版时间：January 9, 2014
• 年：2014
• 卷：118
• 期：1
• 页码：125-133
• 全文大小：444K
• ISSN：1520-5207

文摘

The structure and properties of the electron donor鈥揳cceptor complexes formed between methyl viologen and purine nucleosides and nucleotides in water and the solid state have been investigated using a combination of experimental and theoretical methods. Solution studies were performed using UV鈥搗is and ¹H NMR spectroscopy. Theoretical calculations were performed within the framework of density functional theory (DFT). Energy decomposition analysis indicates that dispersion and induction (charge-transfer) interactions dominate the total binding energy, whereas electrostatic interactions are largely repulsive. The appearance of charge transfer bands in the absorption spectra of the complexes are well-described by time-dependent DFT and are further explained in terms of the redox properties of purine monomers and solvation effects. Crystal structures are reported for complexes of methyl viologen with the purines 2鈥?deoxyguanosine 3鈥?monophosphate (DAD鈥睤AD鈥?type) and 7-deazaguanosine (DAD鈥睞DAD鈥?type). Comparison of the structures determined in the solid state and by theoretical methods in solution provides valuable insights into the nature of charge-transfer interactions involving purine bases as electron donors.