H. Badawi
Feb 28, 2009
Citations
0
Influential Citations
5
Citations
Journal
Journal of Molecular Structure
Abstract
Abstract The C N internal rotations in formohydrazide OHC NH NH 2 and formohydroxamic acid OHC NH OH were investigated at the B3LYP/6-311+G** and MP2/6-311+G** levels of theory. The C N rotational barrier in the molecules was calculated to be about 28–30 kcal/mol. The energies of the molecules were calculated at the B3LYP, MP2, MP4(SDTQ) and CCSD(T) levels of theory with both 6-311G** and 6-311+G** basis sets. From the calculations at all the levels formohydroxamic acid was predicted to exist predominantly in a non-planar near- cis conformation at ambient temperature. From all the calculations formohydrazide was predicted to have a planar cis–syn (C O and N N bonds eclipse each other and NH 2 moiety is syn to C N bond) conformation as the lowest energy structure. The NH 2 inversion barrier in formohydrazide was predicted to be about 5–7 kcal/mol. The vibrational frequencies of the cis–syn formohydrazide were computed at the B3LYP/6-311+G** level and normal coordinate calculations were carried out. Complete vibrational assignments were made on the basis of normal coordinate analyses and experimental infrared and Raman data of the molecule.