Association of 2-acylaminopyridines and benzoic acids. Steric and electronic substituent effect studied by XRD, solution and solid-state NMR and calculations

Research output: Contribution to journalArticleScientificpeer-review

Researchers

Research units

  • University of Technology and Life Sciences
  • University of Jyväskylä
  • University of Opole

Abstract

Eight single crystal X-ray structures, solid-state NMR spectroscopic, and theoretical studies utilizing QTAIM methodology were used to characterize the 2-acyl (alkyl in acyl = methyl, ethyl, t-butyl, and 1-adamantyl) amino-6-R-pyridine/4-R'-benzoic acid (R,R' = H or Me) cocrystals. As expected among alkyl groups 1-adamantyl due to its bulkiness has the most significant effect on the relative positions of molecules in cocrystals. In addition, the subtle electronic and steric effects by the methyl substituents were observed. The theoretical calculations with full geometry optimizations are in agreement with the experimental findings (geometry, energy of hydrogen bonds). Based on the crystal structures and calculations it is concluded that p-methyl substituent in benzoic acid increase the hydrogen bond accepting ability of the C=O oxygen and decreases the hydrogen bond donating ability of OH proton. The N-15 solid-state (CP MAS) NMR chemical shifts prove that molecules in cocrystal are held together by hydrogen bonding. The biggest variation in the N-15 chemical shift of acylamino nitrogen can be related with the size of the alkyl group in acyl moiety. (C) 2013 Elsevier B.V. All rights reserved.

Details

Original languageEnglish
Pages (from-to)157-163
Number of pages7
JournalJOURNAL OF MOLECULAR STRUCTURE
Volume1054-1055
Publication statusPublished - 24 Dec 2013
MoE publication typeA1 Journal article-refereed

    Research areas

  • Cocrystals, X-ray structure, Solid state NMR, QTAIM analysis, Association, HYDROGEN-BOND, CRYSTAL-STRUCTURES, CO-CRYSTALS, INTERMOLECULAR INTERACTIONS, NONCOVALENT INTERACTIONS, SUPRAMOLECULAR SYNTHON, MOLECULAR RECOGNITION, DICARBOXYLIC-ACIDS, CARBOXYLIC-ACIDS, PROTON-TRANSFER

ID: 8688386