Spectral Analysis of 3-(Adamantan-1-yl)-4-Ethyl-1-[(4-Phenylpiperazin-1-yl) Methyl]-1H-1,2,4-Triazole-5(4H)-Thione

Y L Mindarava,M B Shundalau,A A El-Emam,L H Al-Wahaibi,A S Matsukovich,S V Gaponenko

doi:10.1007/s10812-018-0633-5

Abstract

Vibrational IR (3200–650 cm–1) and Raman spectra (3200–150 cm–1) of adamantane-containing 3-(adamantan-1-yl)-4-ethyl-1-[(4-phenylpiperazin-1-yl)methyl]-1H-1,2,4-triazole-5(4H)-thione, which is promising for drug design, were examined. The UV/Vis spectrum (450–200 nm) of the compound in EtOH was measured. Full geometry optimization using density functional theory (DFT) in the B3LYP/cc-pVDZ approximation allowed the equilibrium configuration of the molecule to be determined and IR and Raman spectra to be calculated. Based on these, the experimental vibrational IR and Raman spectra were interpreted and the biological activity indices were predicted. The UV/Vis spectrum of the title compound was simulated at the time-dependent DFT/CAM-B3LYP/cc-pVDZ level with and without solvent effects and at the ab initio multi-reference perturbation theory XMCQDPT2 level. The UV/Vis spectrum that was simulated using the multi-reference XMCQDPT2 approximation agreed very successfully with the experimental data, in contrast to the single-reference DFT method. This was probably a consequence of intramolecular charge transfer.

Highlights

Diamondoids and their derivatives are viable candidates for drug development and delivery systems [1,2,3]
Cc-pVDZ, Time-dependent density functional theory (TDDFT)/Coulomb-attenuating method (CAM)-B3LYP/cc-pVDZ+solvation model density (SMD) (EtOH), and CASSCF(2,4)/XMCQDPT2. These results indicated that the calculations using TDDFT and the CAM-factor were unsatisfactory for describing the observed electronic absorption spectra
Spectral characteristics of 3-(adamantan-1-yl)-4-ethyl-1-[(4-phenylpiperazin-1-yl)methyl]-1H1,2,4-triazole-5(4H)-thione, an adamantane-containing compound that is promising for drug development, were analyzed systematically

Summary

Introduction

Diamondoids (including adamantane as the simplest representative of the family) and their derivatives are viable candidates for drug development and delivery systems [1,2,3]. The electronic absorption spectrum of the studied molecule was calculated in the CASSCF/XMCQDPT2 approximation using the Firefly quantum-chemical suite [35] and standard basis set cc-pVDZ [26]. According to the literature [44] and our calculations [20, 22], bands at 2943, 2934, 2911, 2907, 2888, and 2953 cm–1 in the IR spectrum and lines at 2941, 2917, 2909, 2889, 2855, and 2847 cm–1 in the Raman spectrum belonged to adamantyl CH and CH2 stretching vibrations.

Results

Conclusion