Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1404322 | Journal of Molecular Structure | 2008 | 6 Pages |
Abstract
The electronic structures of C4H2Cl2N2 isomers have been studied by HeI photoelectron spectroscopy (PES) combined with the outer valence Green's function (OVGF) calculations at 6-311++G(d,p) basis sets. The vertical first ionization potentials for 2,6-dichloropyrazine, 2,3-dichloropyrazine, 4,6-dichloropyrimidine and 3,6-dichloropyridazine are determined to be 9.93, 9.89, 10.45 and 10.07Â eV, respectively, and the PE spectra were assigned based on molecular orbital analysis and by comparison with related compounds. The effects of chlorine substituent and different positions of nitrogen atoms in these C4H2Cl2N2 isomers have been carefully analyzed by comparing the C4H2Cl2N2 isomers with their matrixes (pyrazine, pyridazine, pyrimidine). The inductive effect of chlorine substituent leads to the stabilization of the nitrogen lone pair orbitals. The resonance effect predominates over the inductive effect, and the consequence is the destabilization of the Ï orbitals. Owing to the different positions, the effects of nitrogen atoms are different and lead to the different sequence of Ï orbitals.
Related Topics
Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
Shi Yin, Li Yao, Xiao-Qing Zeng, Man-Yu Li, Mao-Fa Ge,