Organic compounds of zirconium. IV. Study of catechol derivatives of zirconium by conductometric and precipitation methods

Abstract

A study of the formation of catechol derivatives of zirconium has been made by conductometric titrations and also by directly analysing the derivatives obtained under different experimental conditions. In conformity with the conclusions obtained from a previous electrometric study, it has been found that mainly monocatechollate derivative is formed when the solution is acidic (pH 1,5-5). The results further confirm the formation of derivatives of the type K₂[Zr(C₆H₄O₂) ₃] and (NH₄)₂[Zr(C₆H₄ O₂)₃] in solution and conductometric studies indicate that the maximum coordination number that zirconium can achieve by chelation with catechol in solution is six. Two new compounds, (NH₄)₂ [Zr(C₆H₄O₂) ₃] and (NH₄) [(OH)Zr(C₆H₄O₂) ₂] have been isolated and it has been shown that the composite of the above derivatives also is in conformity with the conclusions from physic-chemical measurements.