title: Solvent and structural effects in tautomeric 2(6)-hydroxy-4-methyl-6(2)-oxo-1-(substituted phenyl)-1,2(1,6)-dihydropyridine-3-carbonitriles: UV, NMR and quantum chemical study.
abstract: The state of the tautomeric equilibria of 2(6)-hydroxy-4-methyl-6(2)-oxo-1-(substituted phenyl)-1,2(1,6)-dihydropyridine-3-carbonitriles, 2-PY/6-PY, was evaluated using experimental and theoretical methodology. The experimental data were interpreted with the aid of time-dependent density functional (TD-DFT) method. Electron charge density was obtained by the use of Quantum Theory of Atoms in Molecules, i.e. Bader's analysis. Linear solvation energy relationships (LSER) rationalized solvent influence on tautomeric equilibrium. Linear free energy relationships (LFERs) were applied to the substituent-induced NMR chemical shifts (SCS) using SSP (single substituent parameter) and DSP (dual substituent parameter) model. Theoretical calculations and obtained correlations gave insight into the influence of molecular conformation on the transmission of substituent electronic effects, as well as on different solvent-solute interactions, and the state of tautomeric equilibrium.
authors.affiliation: Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade, Serbia.
authors.forename: Ismail
authors.initials: I
authors.lastname: Ajaj
authors.affiliation: Vinča Institute, University of Belgrade, 11000 Belgrade, Serbia.
authors.forename: Jasmina
authors.initials: J
authors.lastname: Markovski
authors.affiliation: Faculty of Forestry, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia. Electronic address: milica.rancic@sfb.bg.ac.rs.
authors.forename: Milica
authors.initials: M
authors.lastname: Rančić
authors.affiliation: Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade, Serbia.
authors.forename: Dušan
authors.initials: D
authors.lastname: Mijin
authors.affiliation: Faculty of Chemistry, University of Belgrade, Studentski trg 3-5, 11000 Belgrade, Serbia.
authors.forename: Miloš
authors.initials: M
authors.lastname: Milčić
authors.affiliation: Faculty of Chemistry, University of Belgrade, Studentski trg 3-5, 11000 Belgrade, Serbia.
authors.forename: Maja
authors.initials: M
authors.lastname: Jovanović
authors.affiliation: Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade, Serbia.
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Marinković
mesh_terms: D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation / Q000187:drug effects; D009570:Nitriles / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D011725:Pyridines / Q000737:chemistry*; D011728:Pyridones / Q000737:chemistry; D011789:Quantum Theory; D012997:Solvents / Q000737:chemistry / Q000494:pharmacology*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics
chemical_list: D009570:Nitriles; D011108:Polymers; D011725:Pyridines; D011728:Pyridones; D012997:Solvents
keywords: DFT; Derivative spectroscopy; Solvent effects; Substituent effects; Tautomerism