Molecular structure and vibrational spectra of N-mesylhydroxylamin and N-mesyl-O-methylhydroxylamin by density functional theory and ab initio Hartree-Fock calculations

The molecular geometry and vibrational frequencies of N-mesylhydroxylamin (N-MHN) and N-mesyl-O-methylhydroxylamin (N-MMHN) in the ground state have been calculated using the Hartree-Fock and density functional method (B3LYP) with 6-31G(d) basis set. The optimized geometric band lengths and bond angles obtained by using HF and DFT (B3LYP) show the best agreement with the experimental data. Comparison of the observed fundamental vibrational frequencies of N-MHN and N-MMHN and calculated results by density functional B3LYP and Hartree-Fock methods indicate that B3LYP is superior to the scaled Hartree-Fock approach for molecular vibrational problems.