Syntheses and Molecular Structures of Novel Alkali Metal Tetraorganylcyclopentaphosphanides and Tetraorganyltetraphosphane‐1,4‐diides

Abstract

Abstract The reaction of sodium with RPCl 2 and PCl 3 (12:4:1) in THF gives Na[ cyclo ‐(P 5 R 4 )] [R = i Pr ( 1 ), Ph ( 2 )], while four equivalents of RPCl 2 [R = Ph, 2,4,6‐Me 3 C 6 H 2 (Mes), t Bu] react with ten equivalents of sodium sand or elemental potassium in refluxing THF to yield the compounds [Na 2 (THF) 5 (P 4 Ph 4 )] ( 3 ), [Na 2 (THF) 4 (P 4 Mes 4 )] ( 4 ), and [Na 2 (THF) 4 (P 4 t Bu 4 )] ( 5 ), or the potassium salt [K 2 (THF) 6 (P 4 Mes 4 )] ( 6 ). Recrystallizing 6 from 1,4‐dioxane/pentane (1:3) also led to [{K(L) 2 } 2 {K(L)} 6 (P 4 Mes 4 ) 4 ·0.5THF] ∞ (L = 1,4‐dioxane) ( 7 ). In the solid state, compounds 3 − 6 exist as isolated ion‐contact complexes, in which the P 4 chain of the (P 4 R 4 ) 2− ligand has a syn arrangement, while a polymeric helical arrangement was observed for 7 . A minor product, [{K(pmdeta)(HP 3 Mes 3 )} 2 {K 2 (P 4 Mes 4 )}]·0.25hexane ( 8 ), was isolated from the reaction of MesPCl 2 and K (1:2.5). Compound 8 contains the first structurally characterized example of a triphosphanide anion, (HP 3 Mes 3 ) − , besides K 2 (P 4 Mes 4 ). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)