Theoretical investigation ( DFT and MP 2 ) of the intermolecular proton transfer in the supersystems uracil - ( H 2 O ) n and uracil - ( CH 3 OH ) n ( n 5 1 , 2 )
نویسندگان
چکیده
Twelve binary and eight ternary H-bonded systems between uracil and water=methanol were investigated at the B3LYP and MP2 theoretical levels using 6 31þG(d) basis functions. The binary and ternary systems that contain the hydroxo-uracil tautomer H-bonded with water and methanol were found to be the most stable complexes. The calculated energy barriers of the intermolecular proton exchange showed that the methanol molecule provokes larger reduction of the energy barrier of the intermolecular proton exchange reactions than the water molecule.
منابع مشابه
Theoretical Investigation of Interaction between 5-Fluorouracil Anticancer Drug with Various Nitrosamine Compounds
We present detailed theoretical studies of the H-bonded complexes formed from interaction between 5-fluorouracil and various six-membered cyclic nitrosamine compounds. In this study, an investigation on intermolecular interactions in X-NU (X = CH2, SiH2,BH, AlH, NH, PH, O and S) complexes is carried out using density functional theory. The calculations are conducted on B3L...
متن کاملAn ab initio quantum chemical investigation of TOMS nmr SHIELDING TENSORS IN Adenine-thymine, Adenine-uracil, Guanine-Cytosine & uracil-quartet: comparison between theoretical and experimental results
We have evaluated the NMR shielding tensors for A:T,G:C,A:U in Watson-crick, and U-quartet. We have computed NMR shielding tensors at B31YP level by using 6-31G(d) basis set. We have compute anisotropy and asymmetry in A:T,G:C,A:U and U-quartet. The NMR shielding tensors were calculated using the GIAO method. The natural bonding orbital analysis (NBO) were performed. NBO calculation have been ...
متن کاملAB Initio Calculations and IR Studies of Tautometric forms of Uracil and Cytosine and comparing results in different temperatures (25˚C, 37˚C and 40˚C).
In this paper,the molecular geometry for three tautomers of uracil and four tautomers of cytosine has been analyzed. vibrational IR spectra of the tautomers were investigated at HF and B3LYP level using the AB initio 6-31G* and LANL2DZ basis sets from the program package Gaussian 98 (A.7 Public Domain version). The physico-chemical and biochemical properties of uracil and cytosine are one of...
متن کاملNew Boron-Nitrogen Analogues of Uracil Derivatives [1]
The reaction o f N.N'-dim ethylurea with l,5-dim ethyl-2,4-bis-(dim ethylam ino)-l,5-diaza-2,4-dibora-3-oxacyclohexan-6-one (2) in the melt proceeds with condensation of the urea to yield two major products: the acid l,3,5-trim ethyl-2-hydroxy-l,3,5-triaza-2-boracyclohexa-4,5-dione (la); and a mixture of the methylammonium (4a) and dimethylammonium salt (4b) of the anion [{C H 3N («-C O N C H 3...
متن کاملDFT-PBE, DFT-D, and MP2 Studies on the H2O•••HNH and HOH•••NH2 Hydrogen Bonds in Water-Aniline Complexes
DFT-GGA method of Perdew-Burke-Ernzerhof (PBE) is used with aug-cc-PVTZ, 6-311++G**, and Def2-TZVP large basis sets to study the hydrogen bond interactions between oxygen lone pair as a donor electron with hydrogen atom connected to the aniline’s nitrogen as an electron acceptor (H2O···HNH-Ph), and nitrogen lone pair with hydrogen of water molecule (Ph-H2N···HOH...
متن کامل