M[P(1,2-O2C6H4)3] (M = K or Na) — Synthesis, characterization, and use in halide abstraction

Abstract

Alkali metal salts of the tris(o-phenylenedioxy)phosphate anion, K[P(1,2-O2C6H4)3] (K[1]) and Na[P(1,2-O2C6H4)3] (Na[1]), were prepared by treating Et3NH[1] with KH or NaH, respectively. X-ray crystallographic analysis of K[1], crystallized in the presence of DMSO, revealed a dimeric structure of formulation K2(DMSO)6[1]2·C7H8. In contrast, the crystal structure of K[1] grown from MeCN consists of fascinating hexagonal macrocycles with formulation {K(MeCN)2[1]}6 with an outside diameter of about 25 Å and a very small hole (≤2.5 Å). Remarkably, these hexagonal macrocycles stack one upon the other with a spacing of about 9.4 Å. The salt, K[1], is an effective halide abstraction agent reacting with (dppp)PdCl2 (dppp = 1,3-bis(diphenylphosphino)propane) (1:1 ratio) or [(cod)RhCl]2 (2:1 ratio) to afford [(dppp)Pd(µ-Cl)]2[1]2 and (cod)Rh[1], respectively. The molecular structures of each complex were determined.