Intra- and intermolecular N-H center dot center dot center dot O = C hydrogen bonds in 1-acyl urea compounds: Synthesis, X-ray structure, conformational and Hirshfeld surface analyses of 1-(2,3-dichlorophenyl)-3-pivaloylurea


Saeed A., HÖKELEK T. , Bolte M., Erben M. F.

JOURNAL OF MOLECULAR STRUCTURE, vol.1245, 2021 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 1245
  • Publication Date: 2021
  • Doi Number: 10.1016/j.molstruc.2021.131271
  • Title of Journal : JOURNAL OF MOLECULAR STRUCTURE
  • Keywords: Crystal structure, Hirshfeld surface analysis, Acyl urea, Natural Bond analysis, Hydrogen bond, GLYCOGEN-PHOSPHORYLASE INHIBITORS, CRYSTAL-STRUCTURE, ACYL UREAS, QUANTITATIVE-ANALYSIS, NBO ANALYSIS, DERIVATIVES, ACYLTHIOUREA

Abstract

Reaction of freshly prepared pivaloyl isothiocyanate with 2,3-dichloroaniline afforded the 1-(2,3-dichlorophenyl)-3-pivaloylthiourea intermediate (2) which was efficiently converted into the title urea (3) by grinding with wet silica supported potassium permanganate under solvent-free conditions in an excellent yield and purity. The structure was confirmed by the spectroscopic, elemental analysis and single crystal X-ray diffraction data. In the most stable conformation, the two C = O groups adopt a mutually opposite orientation. Intramolecular N-H center dot center dot center dot O = C hydrogen bond occurs between the carbonyl (C = O) and urea (-NH) groups forming a six membered pseudo-ring that stabilize the most stable form. The bonding nature of this interaction has been scrutinized by using Natural Bond Orbital (NBO) population analysis, demonstrating the occurrence of a strong hyperconjugative remote interaction between the donor lone pairs located on the carbonyl oxygen and the N-H group. To visualize the intermolecular interactions in the crystal of the title compound, a Hirshfeld surface (HS) analysis was also carried out demonstrating that hydrogen-bonding and van der Waals interactions were the dominant interactions in the crystal packing. The urea groups form centrosymmetric dimers connected by intermolecular N-H center dot center dot center dot O = C hydrogen bonds in a R-2(2) (8) motif. The 2,3-dichloro substitution has important effects on the packing stability, mostly via H center dot center dot center dot Cl contacts, with H center dot center dot center dot Cl/Cl center dot center dot center dot H contributions of 26.1% of the intermolecular interactions. (C) 2021 Elsevier B.V. All rights reserved.