A one step nickel(II)-catalysed synthesis of tris-{2-(2-benzothiazolyl)phenyl}phosphine from tris(hydroxymethyl)phosphine.: Crystallographic evidence of intramolecular nitrogen to phosphorus coordination

Heating together 2-(2-bromophenyl)benzothiazole with tris-(hydroxymethyl)phosphine (generated in situ from tetrakis-(hydroxymethyl)phosphonium chloride and base) and nickel(II)bromide in aqueous ethanol results in the formation of the title triarylphosphine, isolated in a 20% yield. An X-ray crystallography study reveals that all three heterocyclic nitrogen atoms are involved in coordinative interactions with phosphorus, the average N-P distance (2.974 Angstrom) being significantly smaller than the sum of the Van der Waals radii. Normal pyramidal geometry at phosphorus is observed. The crystal structure of the related tris-{2-(2-benzothiazolyl)phenyl} phosphine oxide is also reported. In this molecule, only one short nitrogen to phosphorus interaction is observed (2.888 Angstrom). (C) 1999 Elsevier Science S.A. All rights reserved.