Browsing by Author "Yekeler, H"
Now showing items 1-13 of 13
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Ab initio calculations of solvent effects on guanine and thioguanine tautomerism
Yekeler, H (NATL INST SCIENCE COMMUNICATION-NISCAIR, 2000)The molecular geometries and the relative energies of the ten most stable tautomers of guanine (G1, G2, G3...etc.) and thioguanine (TG1, TG2, TG3...etc.) have been investigated at the HF/3-21G and HF/6-31G** levels in the ... -
Ab initio study on tautomerism of 2-thiouracil in the gas phase and in solution
Yekeler, H (KLUWER ACADEMIC PUBL, 2000)Ab initio geometry optimizations were carried out at the HF/3-21G and HF/6-31+G** levels for the six tautomeric forms of 2-thiouracil (2TU, 2TU1, 2TU2, 2TU3, 2TU4, 2TU5) in the gas phase and in solution. To obtain a more ... -
A computational study on the self-association of -CN, -NH2, -CH3 and -C(CH3)(3) derivatives of 2-pyrrolidinone
Isin, DO; Yekeler, H (ELSEVIER SCIENCE BV, 2004)2-Pyrrolidinone is a model compound for peptides, proteins and antibiotics. We performed full geometry optimizations for -CN, -NH2, -CH3 and -C(CH3)(3) derivatives of 2-pyrrolidinone and their cyclic and open dimer structures ... -
Concerning the solvent effect in the tautomerism of uracil, 5-fluorouracil, and thymine by density-functional theory and ab initio calculations
Yekeler, H; Ozbakir, D (SPRINGER, 2001)The tautomerism of uracil, 5-fluorouracil, and thymine has been investigated in the gas phase and in solution. Electron correlation effects were included in ab initio computations at the MP2 level, and DFT calculations ... -
Hydrogen bonding and dimeric self-association of 2-pyrrolidinone: An ab initio study
Yekeler, H; Guven, A; Ozkan, R (KLUWER ACADEMIC PUBL, 1999)Ab initio calculations on the different associated structures of 2-pyrrolidinone with water and with itself were carried out using 3-21G and 6-31G(*) basis sets at the Hartree-Fock level, including electron correlation ... -
An investigation of keto-enol tautomerism in N-vinyl-2-, and 3-pyrrolidinones using ab initio and density functional theory calculations
Yekeler, H (ELSEVIER SCIENCE BV, 2001)We investigated the protomeric tautomerism of N-vinyl-2-pyrrolidinone (N-V2P) and N-vinyl-3-pyrrolidinone (NV3P) molecules, and considered the three neutral tautomers for NV2P (1a, 1b, 1c) and the five for NV3P (2a, 2b, ... -
Investigation of the addition of water and methanol to protonated acetone and its monohalogenated derivatives in gas phase
Yekeler, H; Ozkan, R (EDITURA ACADEMIEI ROMANE, 2000)The nucleophilic addition reactions of water and methanol to protonated acetone and its monohalogenated derivatives were investigated ill gas phase by using MOPAC6.(1) The transition states were determined by SADDLE method ... -
Molecular modeling study on the relative stabilities of the flotation products for arsenic-containing minerals: dixanthogens and arsenic(III) xanthates
Yekeler, M; Yekeler, H (ACADEMIC PRESS INC ELSEVIER SCIENCE, 2005)The interactions of As(III) ion with C2H5OCS2- and C2H5SCS2-, known as the most popular collector ions, were studied by density functional theory (DFT) at the B3LYP/6-31G** level in connection with the arsenic-containing ... -
Prediction of the acidities of organic bases in aqueous solution using AM1 COSMO solvation model
Guven, A; Yekeler, H; Ozkan, R (ELSEVIER SCIENCE BV, 2000)Potentially tautomeric pyrazole-3-ones were studied, in order to predict their tautomeric equilibrium constants and pK(a) values, using the semiempirical AM1 COSMO solvation model at the SCF level in aqueous solution. Syn ... -
Preferred conformations of some pyrimidine nucleoside reverse transcriptase inhibitors (NRTIs)
Yekeler, H (ELSEVIER SCIENCE BV, 2004)Conformational properties and the energy barriers between the anti and the syn configurations of 3TC, ddC, AZT and d4T have been examined using the density functional theory. For 3TC, ddC and AZT the global minimum structure ... -
Protomeric tautomerisms of N-methylated pyrimidine bases
Yekeler, H (ELSEVIER SCIENCE BV, 2005)Tautomerisms of N1-methyl, N3-methyl, and N1, N3-dimethyl derivatives of uracil, 5-fiuorouracil and thymine have been examined in the gas phase and in water. Geometry optimizations were carried out at the HF/6-31G**. HF/6-31 ... -
Reactivities of some thiol collectors and their interactions with Ag (+1) ion by molecular modeling
Yekeler, H; Yekeler, M (ELSEVIER SCIENCE BV, 2004)The most commonly used collectors for sulfide minerals in the mining industry are the thiol collectors for the recovery of these minerals from their associated gangues by froth flotation. For this reason, a great deal of ... -
Solvent effects on dimeric self-association of 2-pyrrolidinone: An ab initio study
Yekeler, H (KLUWER ACADEMIC PUBL, 2001)Full geometry optimizations were carried out for 2-pyrrolidinone (2-Py) and its dimer structures at the DFT (B3LYP) and HF levels in the gas phase and in solution. Additionally, single-point MP2/6-31G** calculations were ...