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.

1-(4-Chlorophenyl) piperazine: FT-IR, Raman, NMR and Theoretical studies

“…The most shifted carbon peaks to the lowest magnetic field region were found as C15 atom because it is directly bonded to nitrogen atom, so the electron density around this carbon was deshielded more compared to the other carbon atoms [6]. In 13 C Attached Proton Test (APT) NMR spectrum (Figure 7), C15 and C22 does not have directly bonded hydrogen atoms and NMR peaks of them are seen as negative, moreover C2&C3 and C1&C4 peaks were observed as negative, whereas C16&C17 and C18&C20 atoms appear as positive peaks.…”

“…DFT calculations give accurate theoretical results for especially organic molecules and in addition that this method is an easy and cheap method, as well [4][5]. On the other hand, GIAO (gauge including atomic orbitals) method is used to calculated chemical shift values of nuclei of various molecules [6].…”