Crystal structure of poly[(μ3-4-amino-1,2,5-oxa-diazole-3-hydroxamato)thallium(I)]

Acta Crystallogr E Crystallogr Commun. 2020 Feb 11;76(Pt 3):328-331. doi: 10.1107/S2056989020001577. eCollection 2020 Mar 1.

Abstract

The title compound represents the thallium(I) salt of a substituted 1,2,5-oxa-diazole, [Tl(C3H3N4O3)] n , with amino- and hydroxamate groups in the 4- and 3- positions of the oxa-diazole ring, respectively. In the crystal, the deprotonated hydroxamate group represents an inter-mediate between the keto/enol tautomers and forms a five-membered chelate ring with the thallium(I) cation. The coordination sphere of the cation is augmented to a distorted disphenoid by two monodentately binding O atoms from two adjacent anions, leading to the formation of zigzag chains extending parallel to the b axis. The cohesion within the chains is supported by π-π stacking [centroid-centroid distance = 3.746 (3) Å] and inter-molecular N-H⋯N hydrogen bonds.

Keywords: 1,2,5-oxa­diazole; crystal structure; hydroxamic acid; tautomerism; thallium(I).