TD-DFT Investigation of the Magnetic Circular Dichroism Spectra of Some Purine and Pyrimidine Bases of Nucleic Acids
2015 (English)In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 119, no 21, 5476-5489 p.Article in journal (Refereed) Published
We present a computational study of the Magnetic circular dichroism (MCD) spectra in the 200-300 nm wavelength region of purine and its derivative hypoxanthine, as well as of the pyrimidine bases of nucleic acids uracil,thymine, and cytosine, Using the B3LYP and CAM-B3LYP functionals. Solvent effects, are investigated within the polarizable continuum model and by inclusion of explicit water molecules. In, general; the computed spectra are found to be in good agreement with the experimental ones, aprt from some overall blue shifts. Both the pseudo-A term shape of the MCD spectra of the purines and the B term shape of the spectra of pyrimidine base are reproduced. Our calculations also correctly reproduce the reversed phase of the MCD bands in purine compared to,that of its derivatives present in nucleic acids. Solvent effects are sizable and system specific,but they do not in general alter the qualitative shape of the spectra. The bands are dominated the-bright pi -greater than pi* transitions; and our calculations in solution nicely reproduce theft energy differences, improving the estimates obtained in the gas phase. Shoulders are predicted for purine and uracil due to n -greater than pi* excitations, but they are too weak to be observed in the. experiment.
Place, publisher, year, edition, pages
American Chemical Society , 2015. Vol. 119, no 21, 5476-5489 p.
IdentifiersURN: urn:nbn:se:liu:diva-119800DOI: 10.1021/jp512468kISI: 000355495100043PubMedID: 25648759OAI: oai:DiVA.org:liu-119800DiVA: diva2:827229
Funding Agencies|PRIN [2010ERFKXL_008]; University of Trieste [CHIM02-Ricerca]2015-06-262015-06-262016-01-15