The crystal structure of 5-(trifluoromethyl)picolinic acid monohydrate reveals a water-bridged hydrogen-bonding network

Abstract

The title compound [systematic name: 5-(trifluoromethyl)pyridine-2-carboxylic acid monohydrate], C7H4F3NO2·H2O, is the acid hydrate of a pyridine with a carboxylic acid group and a trifluoromethyl substituent situated para to one another on the aromatic ring. The molecule forms a centrosymmetric water-bridged hydrogen-bonding dimer with graph-set notation R44 (12). Hydrogen-bonding distances of 2.5219 (11) and 2.8213 (11) Å are observed between the donor carboxylic acid and the bridging water acceptor, and the donor water and carbonyl oxygen acceptor, respectively. The dimers are further linked into a two-dimensional sheet via two longer intermolecular hydrogen-bonding interactions between the second hydrogen atom on the bridging water molecule and both a pyridine nitrogen atom and carbonyl oxygen with distances of 3.1769 (11) and 2.8455 (11) Å, respectively. The trifluoromethyl groups extend out the faces of the sheet providing for F...F and C—H...F contacts between the sheets, completing the three-dimensional packing.

Keywords

• crystal structure
• hydrogen bonding
• picolinic acid derivatives
• trifluoromethyl group