Computational Studies of C5H5N Isomers

Abstract

Seven C5H5N isomers (Pyridine, 1-cynao-1,3-butadiene, Azafulvene, 2-methylene-3-butenenitrile, 2,4-cyclopentadiene-1-imine, 4-cyano-1-butyne, Bicyclo [1.1.0] butane -1-carbonitrile)have been studied computationally using the Gaussian-4 (G4) compound model with the Gaussian 09 suit of programs. Quantum chemical parameters such as dipole moment, bond distance and angle, enthalpy of formation, rotational constants and vibrational frequencies were obtained and compared with experimental values (where available). Pyridine was predicted to be the most stable among the C5H5N isomers with the least standard enthalpy of formation of 28.737 kcal/mol. The calculated bond distances and angles for pyridine were observed to be in excellent agreement with the measured experimental values. Furthermore, the calculated rotational constants (A=6.06773, B=5.831586, C=2.97366) and dipole moment (2.33 D) for pyridine were accurately predicted when compared to the experimentally determined values. Thus, the high accuracy obtained from this quantum chemical calculation indicates that other C5H5N isomers with no experimental values are well predicted with the Gaussian-4G4 compound model. Keywords: computational, isomers, pyridine