Syntheses of Cadmium Complexes of Phosphoryl Triamide from Aqueous Media

Abstract

Reactions between phosphoryl triamide and CdX₂ (X= Cl, Br, I) were studied mainly in aqueous solutions.
Cd {PO (NH₂)₃}Cl₂ [1] was obtained by adding acetone immediately after the preparation of CdCl₂ and PO(NH₂)₃ mixture with a P/Cd atomic ratio of 1.0 at room temperature. But in prolonged reaction time (-96 hr) and elevated temperature (-60°C), PO(NH₂)₃ was hydrolyzed to precipitate mainly monoamidophosphate, CdPO₃ NH₂ ⋅ xH₂O, via diamidophosphate.
By the reaction with CdBr₂, a new complex Cd{PO(NH₂)₃} Br₂ [2] was obtained as preci pitate with a P/Cd atomic ratio of 1.0 for half an hour at room temperature. Furthermore, the solid mixtures of 1: 1 molar ratio of PO(NH₂)₃ and CdX₂ (X=CI, Br, I) were wetted with a small amount of water, mixed thoroughly, and then dried in a vacuum desiccator, to yield new complexes Cd{PO(NH₂)₃} X₂(X=Cl, Br, I) [3].
The X-ray diffraction pattern of the Br complex [3] is identical with [2] but that of the Cl complex [3] is entirely different from [1]. Their IR spectra suggest that all the complexes [1], [2], and [3] are 6-coordinate polynuclear complexes with halogen bridges, in which PO(NH₂)₃ is bound to the central Cd atom as a bidentate ligand through both the phosp horyl -O atom and the amide-N atom. The measurements of electric conductivity and the depression of freezing point of their dilute aqueous solutions reveal that these complexes dissociate into Cd(II) ion, halide ion, and PO(NH₂)₃.