Thermal Decomposition Products of Mn (II) and Cd(II) Complexes of Phosphoryl Triamide

Abstract

Thermal decomposition products of [Mn{PO(NH₂)₃}₂] and Cd{PO(NH₂)₃}Cl₂ were investigated by IR spectroscopy, X-ray diffractometry, paper chromatography, chemical analysis, etc. By heating under reduced pressure (5 x 10-2 mmHg), these complexes are converted mainly into oligomeric condensed phosphoryl amide at 140-200° C, followed by the formation of highly cross-linked condensed phosphates at 300-700° C. All these condensed phosphates are assumed to be linked with P=N-P and P-NH-P bonds by IR spectra, and amorphous by X-ray diffraction; the former is decomposed to orthophosphates in aqueous 6 N H₂S0, solution at a room temperature, but insoluble in water, whereas the latter insoluble in aqueous 6 N H₂SO₄ (at a room temperature), water, and, various organic solvents.
By heating in an air, these complexes give mainly highly cross-linked condensed phosphates at about 300∼400° C temporarily, and the breaking of P=N-P and P-NH-P linkages of the condensed phosphates occurs by atmospheric moisture from about 600° C and 500-600° C in Mn and Cd complexes, respectively. Mn complex loses all nitrogen and chlorine to form Mn₂(P₄O₁₂) at 1000° C. In Cd complex, the rapid formation of Cd₁₈Cl₂(PO₄)₆ was observed by X-ray diffractometry at about 500∼600° C, which loses all nitrogen and chlorine to form Cd₂P₂O₇ at 1000° C. The relations between the thermal decomposition products and the structures of PO(NH₂)₃ complexes are discussed.