Theoretical studies on the conformations of selenamides

Ab initio HF/6-31+G*, MP2/6-31+G*, B3LYP/6-31+G* level calculations have been performed on HSe–NH2 to estimate the Se–N rotational barriers and N-inversion barriers. Two conformers have been found with syn and anti arrangement of the NH2 hydrogens with respect to Se–H bond. The N inversion barriers in selenamide are 165, 2,47, 1,93 kcal/mol and the Se–N rotational barriers are 6,58, 6,56 and 6,12 kcal/mol respectively at HF/6-31+G*, MP2/6-31+G* and B3LYP/6- 31+G* levels respectively. The TN right arrow sigma *Se–H negative hyperconjugation is found to be responsible for the higher rotational barriers.