CaPyrithione2

CaPyrithione2 is a calcium(II) coordination complex consisting of one calcium ion coordinated by two pyrithionate ligands, resulting in a neutral compound with the approximate formula Ca(Pyrithionate)2. In this context, pyrithionate refers to the deprotonated form of pyrithione, a sulfur- and oxygen-donor chelating ligand. The complex is discussed in coordination chemistry as an example of a calcium(II) dication stabilized by bidentate ligands.

Structure and bonding: The two pyrithonato ligands bind through sulfur and the pyridinone-derived oxygen, giving a chelating environment around calcium. Calcium typically exhibits high coordination numbers; Ca(Pyrithionate)2 is predicted to adopt a high-coordination geometry, such as a distorted octahedral or higher-order arrangement. The complex is generally considered to be thermodynamically stable under moderate conditions.

Synthesis: Preparation is typically envisioned by metathesis of a calcium salt (for example calcium chloride) with sodium pyrithionate in aqueous or mixed solvent systems, followed by crystallization. Alternative routes involve direct coordination of pyrithione to calcium centers under controlled pH and temperature, with purification by filtration and drying.

Properties: Ca(Pyrithionate)2 is described as a white to pale powder, sparingly soluble in water and soluble in certain polar organic solvents. It is sensitive to strong acids and bases and may decompose on heating to release pyrithione ligands.

Applications and research: The compound is mainly of theoretical and educational interest, illustrating multinuclear coordination of calcium by bidentate ligands. Limited data exist on its practical applications; related zinc and copper pyrithione complexes are better studied for antimicrobial uses.

Safety: Handle with standard laboratory precautions. Pyrithione derivatives can be irritant; avoid inhalation and skin contact.