ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Synthesis and evaluation of molecular structure from torsional scans, study of molecular characteristics using spectroscopic and DFT methods of some thiosemicarbazones, and investigation of their anticancer activity

K. Srishailam, K. Ramaiah, K. Laxma Reddy, B. Venkatram Reddy, and G. Ramana Rao

Department of Physics, SR University, Warangal, India

E-mail: bvreddy67@yahoo.com

Received: 14 November 2020  Accepted: 8 March 2021

Abstract:

Synthesis of 2-((2-aminopyridin-3-yl) methylene) hydrazinecarbothioamide (APHT) was attempted. Elemental analysis and NMR spectra were used to ascertain its formation. Torsional potential energy scans for all five of its rotating bonds were made to get approximate dihedral angles. UV–Vis spectra were measured for APHT and 2-((2-aminopyridin-3-yl) methylene)-N-methylhydrazinecarbothioamide (APMHT). Their anticancer activity was determined experimentally, for human carcinoma cell lines pertaining to liver, colorectal, and lung. For both APHT and APMHT, frontier molecular orbital parameters, NLO behaviour, and NBO characteristics were determined using DFT/B3LYP/6-311++G(d,p) level of theory. TD-DFT was used to compute absorption maxima (λ_max) of electronic transitions for both molecules in DMSO-d₆ solvent. Frontier molecular orbitals were used to understand origin of UV–Vis spectra and chemical reactivity of the two molecules. Good agreement was found between measured and computed structure parameters. This is also true of experimental and theoretical UV–Vis spectra. The computations demonstrated that both the molecules were good for NLO applications, which was substantiated by NBO analysis. Existence of bifurcated intramolecular hydrogen bond was predicted for both APHT and APMHT.

Keywords: Hydrazinecarbothioamides; Torsional potentials; Barrier heights; Vibrational spectra; DFT; Anticancer activity

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-021-01595-x

Chemical Papers 75 (7) 3635–3647 (2021)