Conformational stability and normal coordinate analyses for 1-halovinyl azides CH2=CX-NNN (X is F, Cl and Br).
The conformational behavior of 1-halovinyl azides CH2=CX-NNN (X=F, Cl and Br) were investigated by DFT-B3LYP and ab initio MP2 calculations with the 6-311++G** basis set. The molecules were predicted to exist predominantly in the trans (the vinyl CH2=CH- and the azide -NNN groups are trans to each other) conformation. The relative energy between cis and trans were calculated to decrease in order: bromide>chloride>fluoride. Full optimization was performed at the ground and transition states in the molecule at both MP2 and B3LYP levels. The barrier to internal rotation around the C-N single bond in the three molecules was calculated to be about 4-5 kcal mol(-1). The vibrational frequencies were computed at the DFT-B3LYP level and the calculated infrared and Raman spectra of the cis- trans mixture of the three molecules were plotted. Complete vibrational assignments were made on the basis of normal coordinate calculations for both stable conformers of the three molecules.
Badawi
Hassan M
HM
Department of Chemistry, King Fahd University of Petroleum and Minerals, 31261 Dhahran, Saudi Arabia. hbadawi@kfupm.edu.sa
Förner
Wolfgang
W
Al-Ghamdi
Khalid S
KS
D001386:Azides / Q000737:chemistry*; D006219:Halogens / Q000737:chemistry*; D008968:Molecular Conformation; D016011:Normal Distribution; D013053:Spectrophotometry; D013237:Stereoisomerism; D014753:Vinyl Compounds / Q000737:chemistry*
D001386:Azides; D006219:Halogens; D014753:Vinyl Compounds