py(2)P(2)S(7): a bis(pyridine)adduct stabilized phosphorus sulfide.

The new phosphorus sulfide P(2)S(7), stabilized as the bis(pyridinium) adduct, was obtained from the reaction of P(4)S(10) and sulfur in pyridine, and could be isolated in the form of colourless block-shaped crystals which were characterized using single crystal X-ray diffraction. Coordination of pyridine is weak (d(P-N) = 187 pm) which is supported also by quantum chemical calculations.

New salts of the waterstable P(2)Se(6)(4-) anion.

The structures of two new salts of the P(2)Se(6)(4-) anion, [(py(2)Li)](4)[P(2)Se(6)].2py and [pyH](4)[P(2)Se(6)].H(2)O, prepared using a new synthetic route in solution starting from easily available educts, are presented. The salts are characterized also in solution by means of multinuclear ((31)P, (77)Se, (7)Li) NMR spectroscopy. The (31)P and (77)Se NMR spectrum of the waterstable P(2)Se(6)(4-) anion are discussed in detail for the first time. The chemical shift of the P(2)Se(6)(4-) anion in the Li(+) salts depends strongly on the solvent used. Remarkably, the newly synthesized salts are stable in water.

An unusual binary phosphorus-tellurium anion and its seleno- and thio- analogues: P(4)Ch(2)(2-) (Ch = S, Se, Te).

We present an unusual discrete P-Te anion, P(4)Te(2)(2-), which is readily obtained by the oxidation of white phosphorus with Te(2)(2-) in N-methyl imidazole at ambient temperature. According to the (31)P and (125)Te NMR spectra, the anion P(4)Te(2)(2-) had a bicyclo[1.1.0]tetraphosphane ("butterfly") structure with the tellurium atoms in the exo positions. The anion was remarkably stable at ambient temperature and disproportionated only slowly with the formation of elemental tellurium. P(4)Te(2)(2-) is the first P-Te anion with a bicyclo[1.1.0]tetraphosphane structure. When Se(2)(2-) or S(2)(2-) was reacted with white phosphorus, the analogous seleno- and thiophosphate anions P(4)Se(2)(2-) and P(4)S(2)(2-) were formed, thus completing the series of phosphorus-chalcogen anions P(4)Ch(2)(2-) (Ch = S, Se, Te). The synthesis of P(4)Te(2)(2-) demonstrated that binary P-Te anions do exist as stable species in solution.

Structural and NMR spectroscopic investigations of chair and twist conformers of the P2Se8(2-) anion.

Four new salts of the P2Se8(2-) anion have been prepared, starting from easily available reagents using different reaction strategies including reaction of the elements, oxidation of P4Se3 with alkalimetal diselenides and elemental selenium, and the use of an ionic liquid as a reaction medium. Multinuclear NMR investigations show the presence of both chair-P2Se8(2-) and twist-P2Se8(2-) in solution, with twist-P2Se8(2-) being the predominant conformer. The interconversion between the two conformers is slow on the NMR time scale. Structural investigations of the new salts by single-crystal X-ray diffraction show that chair-P2Se8(2-) is the conformer mostly found in the solid state. A first structural characterization of twist-P2Se8(2-) is reported. The bonding situation in the P2Se8(2-) anion as well as the relative stability of the chair, twist, and boat conformers was elucidated by quantum chemical calculations.