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 (MV) 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 (TD) 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 GMP (DAD′DAD′ type) and 7-deazaguanosine zG (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.

Viologen–cucurbituril host/guest chemistry – redox control of dimerization versus inclusion

“…The M06-2X/6-311G(d,p) approach in combination with the PCM was found to provide good results for the description of p-stacking interactions of viologen derivatives. 65 EPR spectroscopy. EPR spectra were recorded on a CMS 800 EPR spectrometer 8400 and measurements were carried out with solutions of the calixarene-bis-viologens compounds C23 4+ and C24 4+ , along with their model ligands, namely MC3 2+ and MC4 2+ , in the absence and in the presence of CB [7].…”

Theoretical Investigation of Charge Transfer in Metal Organic Frameworks for Electrochemical Device Applications

“…49,53 Interaction energies were calculated by the supramolecular approach, i.e., by subtracting energies of the isolated donor/acceptor species and counterion ( ) from that of complex. 54 Basis set superposition energy corrections were taken into account.…”

Solvent‐dependent mechanistic aspects for the redox reaction of paraquat in basic solution

“…It is worthwhile noting that the M06‐2X predicted Gibbs free energy profiles and thermodynamics have been successfully used to investigate mechanisms of many prototypical organic reactions, for example, the basic anion (HCO 3 − ) assisted C‐H activation, [ 35 ] effect of solvent polarity on the reaction energetics and selectivity of alkyne hydrochalcogenation, [ 36 ] organocatalytic asymmetric Povarov reactions of anilines and aldehydes, [ 37 ] regioselectivity for 1,3‐dipolar cycloadditions of diazomethane, [ 38 ] and even for the PQ‐containing charge transfer complexes. [ 39 ] Reasonable agreement between computation and experiment validates the computational protocols and demonstrates the significance of the theoretical results.…”