title: Tautomeric transformation of temozolomide, their proton affinities and chemical reactivities: A theoretical approach.
abstract: The gas-phase geometry optimizations of bare, mono- and dihydrated complexes of temozolomide isomers were carried out using density functional calculation at the M06-2X/6-31+G(d,p) level of the theory. The structures and protonation energies of protonated species of temozolomide are reported. Chemical indices of all isomers and protonated species are also reported. Energies, thermodynamic quantities, rate constants and equilibrium constants of tautomeric and rotameric transformations of all isomers I1↔TZM↔HIa↔HIb↔I2↔I3 in bare and hydrated systems were obtained.
authors.affiliation: Department of Chemistry, Faculty of Engineering, Rajamangala University of Technology Isan, KhonKaen Campus, KhonKaen 40000, Thailand; Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, KhonKaen University, KhonKaen 40002, Thailand. Electronic address: wichien.sa@rmuti.ac.th.
authors.forename: Wichien
authors.initials: W
authors.lastname: Sang-Aroon
authors.affiliation: Supramolecular Chemistry Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Pathumwan, Bangkok 10320, Thailand.
authors.forename: Vithaya
authors.initials: V
authors.lastname: Ruangpornvisuti
authors.affiliation: Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, KhonKaen University, KhonKaen 40002, Thailand; Thailand Center of Excellence in Physics, CHE, Ministry of Education, Bangkok 10400, Thailand. Electronic address: vittaya@kku.ac.th.
authors.forename: Vittaya
authors.initials: V
authors.lastname: Amornkitbamrung
mesh_terms: D003606:Dacarbazine / Q000031:analogs & derivatives* / Q000737:chemistry; D005740:Gases / Q000737:chemistry; D007536:Isomerism; D008962:Models, Theoretical; D011522:Protons; D011789:Quantum Theory; D000077204:Temozolomide; D013816:Thermodynamics
chemical_list: D005740:Gases; D011522:Protons; D003606:Dacarbazine; D000077204:Temozolomide
keywords: Chemical reactivity; Proton affinity; Rate constants; Reaction energy; Temozolomide isomers; Thermodynamic properties