Synthesis, structural characterization, and theoretical studies of new pyrazole (E)-2-{[(5-(tert-butyl)-1H-pyrazol-3-yl)imino]methyl}phenol and (E)-2-{[(1-(4-bromophenyl)-3-(tert-butyl)-1H-pyrazol-5-yl]imino]methyl}phenol

Abstract In this paper, theoretical and experimental studies of two new Schiff bases were performed. The ( E )-2-{[(5-( tert -butyl)-1 H -pyrazol-3-yl)imino]methyl}phenol ( 3 ) and ( E )-2-{[(1-(4-bromophenyl)-3-( tert -butyl)-1 H -pyrazol-5-yl]imino]methyl}phenol ( 5 )compounds were characterized by spectroscopic techniques, (i.e. MS, NMR, FT–IR, UV–vis, and single-crystal X–ray diffraction). The molecular geometry of both compounds in the ground state, vibrational frequencies, and chemical shift were calculated by using the functional density theory method, with B3LYP as functional and 6-31G** as basis set, using the GAUSSIAN 09 program package. With the VEDA 4 program, the vibrational frequencies were allocated in terms of potential energy distribution (PED). In this paper, theoretical and experimental studies of two new Schiff bases were performed. The ( E )-2-{[(5-( tert -butyl)-1 H -pyrazol-3-yl)imino]methyl}phenol ( 3 ) and ( E )-2-{[(1-(4-bromophenyl)-3-( tert -butyl)-1 H -pyrazol-5-yl]imino]methyl}phenol ( 5 ) compounds were characterized by spectroscopic techniques, (i.e. MS, NMR, FT-IR, UV–vis, and single-crystal X-ray diffraction). The molecular geometry of both compounds in the ground state, vibrational frequencies, and chemical shift were calculated by using the functional density theory method, with B3LYP as functional and 6-31G** as basis set, using the GAUSSIAN 09 program package. With the VEDA 4 program, the vibrational frequencies were allocated in terms of potential energy distribution (PED). Molecular stabilities were determined in terms of softness and hardness, and the values were determined from the energies of HOMO and LUMO orbitals. Remarkably, good agreements between the calculated IR, NMR and UV–vis spectra in comparison to those experimental ones, were found.