Structural characterization of polymeric potassium salts with 2-thiobarbituric acid: influence of organotin(IV) chlorides on potassium cation solvation

• Published in: Journal of coordination chemistry Vol. 65; no. 7; pp. 1107 - 1117
• Main Authors: Kubicki, Maciej, Owczarzak, Anita, Balas, Vasilios Ι., Hadjikakou, Sotiris K.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis Group 10-04-2012; Taylor & Francis Ltd
• Subjects: Acids; Chemistry; Coordination polymers; Hydrates; Potassium complex; Thiobarbituric acid
• ISSN: 0095-8972; 1029-0389
• DOI: 10.1080/00958972.2012.660148

Slow evaporation of the filtrate derived from the reaction in water between 2-thiobarbituric acid (H
2
TBA) and equimolar amount of potassium hydroxide results in the formation of crystals of two coordination polymers: unhydrated [K(μ
3
-S,O-HTBA)]
n
(1) and hydrated [K(μ
2
-S,O-HTBA)(μ
2
-S,O-H
2
TBA)(μ-H
2
O)]
n
(2), which depend on the absence (1) or presence (2) of methanol solutions of organotin chloride. The hydrate 2 was isolated from the filtrates when di-n-butyltin dichloride, dimethyltin(IV) dichloride, diphenyltin(IV) dichloride, tri-n-butyltin chloride, or triphenyltin(IV) chloride were used during the reaction. The crystal structures show that coordination of potassium occurs through the S and O donors. The potassiums have distorted tetragonal bipyramidal and distorted cubic coordination environments in 1 and distorted square antiprism coordination in 2. Both structures exhibit intermolecular N-H ··· O hydrogen-bond interactions, which form TBA chains while the water in 2 produces a richer hydrogen-bonded structure.