Original scientific paper

https://doi.org/10.5562/cca3347

Aggregation in Three Benzamide or Pyridylcarboxamide Hydrates: Formation of 1D Chains Comprising Water Molecules in a Chloro(pyridyl)benzamide Dihydrate

Pavle Mocilac ; School of Chemical Sciences, Dublin City University, Dublin 9, Ireland
John F. Gallagher orcid.org/0000-0003-4130-4556 ; School of Chemical Sciences, Dublin City University, Dublin 9, Ireland
Christian Jelsch ; CRM2, CNRS, Faculté des Sciences et Technologies, Université de Lorraine, BP 70239, Boulevard des Aiguillettes, 54506 Vandoeuvre-dès-Nancy, France

Abstract

Three benzamide hydrated derivatives as para-methyl-N-(3-pyridyl)benzamide monohydrate (I) or Mpm ∙ H2O; N-(3-fluorophenyl)-4-pyridylcarboxamide monohydrate (II) or NpmF ∙ H2O and para-chloro-N-(3-pyridyl)benzamide dihydrate (III) or Clpm ∙ 2H2O are obtained from a series of crystallization experiments using a range of solvents to obtain polymorphs and solvates (hydrates). Most of the crystallization experiment attempts did not provide hydrates and yielded the starting parent crystalline materials. However, from the experiments, two benzamides, Mpm as a monohydrate and Clpm as a dihydrate were isolated and together with a carboxamide monohydrate as NpmF ∙ H2O are reported herein. The water molecules play a key role in crystal structure formation using classical hydrogen bonding via amide N–H···OH2, O–H···Npyridine and O–H···O=C interactions. They compensate for the excess of strong hydrogen bonding acceptors over donors in the benzamide/pyridinecarboxamide molecules, by participating as O-H hydrogen bond donors twice and usually as an O acceptor once. In the Clpm dihydrate, both water molecules form hydrogen bonded chains along the a-axis direction. The lack of hydrate formation in the majority of related benzamides is presumably related to the relative hydrophobicity of these compounds.

This work is licensed under a Creative Commons Attribution 4.0 International License.

Keywords

benzamide; carboxamide; contact enrichment; hydrate; hydrogen bonding; interactions; structural systematics

Hrčak ID:

204157

URI

https://hrcak.srce.hr/204157

Publication date:

4.6.2018.

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