1-(2-NITROPHENYL)PIPERAZINE: NMR, RAMAN, FTIR AND DFT STUDIES

Abstract

Structure of 1-(2-nitrophenyl)piperazine (NPP, C10H13N3O2) was characterized by nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) and Raman techniques. The conformational analysis, nuclear magnetic shielding tensors, normal mode frequencies and corresponding vibrational assignments of NPP were examined by the density functional theory (DFT), using the Becke-3-Lee-Yang-Parr (B3LYP) functional and the 6-31G(d) and 6-311++G(d,p) basis sets. Reliable vibrational assignments were investigated by the total energy distributions (TED) obtained with the scaled quantum mechanical (SQM) method. The hydrogen of NH group in piperazine and the phenyl fragment of NPP equatorially oriented relative to piperazine. There is a good agreement between the experimentally determined nuclear magnetic shielding tensors and vibrational frequencies of NPP and those predicted theoretically