Monomeric, Dimeric, and Trimeric Triselenometaphosphate

Abstract

Monomeric triselenometaphosphate PSe₃ ⁻ (1), its dimer (2) and trimer (3) are obtained for the first time in solution by oxidation of P₄Se₃ with M₂Se₂ (M = Li, Na) and elemental selenium and are fully characterized by ³¹P and ⁷⁷Se NMR. The equilibrium between 1, 2 and 3 depends strongly on the solvent and is shifted to the side of PSe₃ ⁻ in HMPA or DMPU. Monomeric trithiometaphosphate PS₃ ⁻ (4) is obtained by the analogous reaction of P₄Se₃ with Li₂S₂ and elemental sulfur. 1 reacts with Se₂ ²⁻ and with P₄Se₃ to give the new selenophos-phates P₂Se₈ ⁴⁻ and P₄Se₇ ²⁻, respectively. Further reaction of P₄Se₇ ²⁻ with P₄Se₃ yields the new anion P₉Se₁₄ ³⁻; its structure in the Bu₄P⁺ salt is determined by X-ray crystallography.

Keywords::

• selenophosphates
• triselenometaphosphate
• trithiometaphosphate
• ³¹P and ⁷⁷Se NMR
• X-ray structure determination