jp410348b_si_001.pdf (1.28 MB)
Structure and Electronic Spectra of Purine–Methyl Viologen Charge Transfer Complexes
journal contribution
posted on 2014-01-09, 00:00 authored by Almaz
S. Jalilov, Sameer Patwardhan, Arunoday Singh, Tomekia Simeon, Amy A. Sarjeant, George C. Schatz, Frederick D. LewisThe structure and properties of the
electron donor–acceptor
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–vis 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′-deoxyguanosine
3′-monophosphate (DAD′DAD′ type) and 7-deazaguanosine
(DAD′ADAD′ 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.