Competing intramolecular NAH...C hydrogen bonds and extended intermolecular network in 1-(4-chlorobenzoyl)-3-(2-methyl-4- oxopentan-2-yl) thiourea analyzed by experimental and theoretical methods

AAMER SAEED; ASMA KHURSHID; JERRY P. JASINSKI; C. GUSTAVO POZZI; ADOLFO C. FANTONI; MAURICIO F. ERBEN

CHEMICAL PHYSICS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2014 vol. 431 p. 39 - 46

0301-0104

Abstract The synthesis of a novel 1-acyl-thiourea species (C14H17N2O2SCl), has been tailored in such a way that two distinct N?H···O=C intramolecular competing hydrogen bonds are feasible. The X-ray structure analysis as well as the vibrational (FT-IR and FT-Raman) data reveal that the S conformation is preferred, with the C=O and C=S bonds of the acyl-thiourea group pointing in opposite directions. The preference for the intramolecular N2?H···O1=C7 hydrogen bond within the ?C(O)NHC(S)NH? core is confirmed. The Natural Bond Orbital and the Atom in Molecule approaches demonstrate that a strong hyperconjugative lpO1→ s*(N2?H) remote interaction between the acyl and the thioamide N2?H groups is responsible for the stabilization of the S conformation. Intermolecular interactions have been characterized in the periodic system electron density and the topological analysis reveals the presence of an extended intermolecular network in the crystal, including a Cl∙∙∙N interaction playing a relevant role in crystal packing.