title: Structure and electronic spectra of purine-methyl viologen charge transfer complexes.
abstract: The 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 (1)H 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.
authors.affiliation: Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 20208-3113, United States.
authors.forename: Almaz S
authors.initials: AS
authors.lastname: Jalilov
authors.forename: Sameer
authors.initials: S
authors.lastname: Patwardhan
authors.forename: Arunoday
authors.initials: A
authors.lastname: Singh
authors.forename: Tomekia
authors.initials: T
authors.lastname: Simeon
authors.forename: Amy A
authors.initials: AA
authors.lastname: Sarjeant
authors.forename: George C
authors.initials: GC
authors.lastname: Schatz
authors.forename: Frederick D
authors.initials: FD
authors.lastname: Lewis
mesh_terms: D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D010269:Paraquat / Q000737:chemistry*; D011522:Protons; D011687:Purines / Q000737:chemistry*; D011789:Quantum Theory; D013056:Spectrophotometry, Ultraviolet
chemical_list: D011522:Protons; D011687:Purines; D010269:Paraquat; C030985:purine