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Theoretical Study of Structures and Spectra of Small Anticancer Drugs: Fluorouracil, Hydroxyurea, and Tirapazamine
Author(s) -
Chong Delano P.
Publication year - 2016
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.201400443
Subject(s) - chemistry , density functional theory , spectral line , solvation , dipole , ab initio , polarizability , polarizable continuum model , time dependent density functional theory , perturbation theory (quantum mechanics) , molecular physics , configuration interaction , computational chemistry , molecule , quantum mechanics , physics , organic chemistry
Abstract The structures and spectra of anticancer drug molecules fluorouracil, hydroxyurea, and tirapazamine are studied with ab initio methods and density functional theory. We optimize the geometry of the three molecules in gas phase and compute the vibrational spectra, dipole moments, and static dipole polarizabilities. Based on the coupled cluster method with single and double excitations (CCSD) results as standard for comparison for the geometry of fluorouracil and hydroxyurea, we conclude that third‐order Moeller‐Plesset perturbation (MP3) theory is more reliable than its second‐order shortcut (MP2) or the popular method in density functional theory known as Becke three‐parameter Lee‐Yang‐Parr exchange‐correlation functional (B3LYP). Using the best methods based on past experience, we also calculate the vertical ionization energies of both valence and core electrons. Most of the results are new predictions, while others compare well with previous calculations and with available experimental data. On the other hand, the absorption spectra of the aqueous solution of three title molecules are studied with time‐dependent DFT using the polarizable continuum model in conjunction with the nonequilibrium solvation method. Out of over 30 exchange‐correlation functions/models, five are found to be more reliable than the others when compared with the observed UV/visible spectra of fluorouracil and tirapazmine.