Synthesis, Characterization, Spectroscopic and X-Ray Diffraction Studies of Novel Pair of Thiourea Derivatives of 2-Morpholin-4-yl-ethylamine

Abstract

A novel pair of thiourea derivatives of cinnamoyl and benzoyl with 2-morpholin-4-yl-ethylamine namely 1-(2-morpholinoethyl)-3-cinnamoylthiourea (I) and 1-(2-morpholinoethyl)-3-benzoylthiourea (II) have been successfully synthesized and characterized via IR, NMR, CHNS-O, UV techniques and X-ray diffraction for single crystal. The important stretching bands for n(C=O), n(N-H), n(C=S) and n(C-N) were around 1600, 3300, 700 and 1300 cm^-1, respectively, were shown by IR spectra. There is an important chromophore, C=O, observed in the UV spectra with a maximum absorption at around 240 nm. The crystal structures of (I) and (II) have been determined by X-ray diffraction analysis for single crystal. Both the molecules adopt trans-cis configuration relative to the position of phenyl ring and 2-morpholin-4-yl-ethyl groups with respect to the thiono S atom, across C-N bonds. In both compounds, there were two intramolecular hydrogen bonds, N-H···O and N-H···N, that form of pseudo-six-membered and pseudo-five-membered rings, respectively, in addition to a pseudo-five-membered ring, C7-H6···O1, in (I) which stabilizes the molecule. In the crystal frame, the molecules were linked by intermolecular hydrogen bonds N-H···O and C-H···O forming polymeric (I) and chain network (II). ¹H NMR spectra show chemical shift at d_H 10.86-10.97 ppm and d_H 9.07-9.12 ppm were assigned for NH protons. While the chemical shift for ¹³C NMR analysis of C=S and C=O presence at d_C 169-179 ppm.