Bis(thiophosphinoyl)amines and their neutral cobalt(II) complexes, containing stable tetrahedral CoS4 cores. Crystal structures of NH(SPMe2)(SPPh2) and [Co{(SPMe2)(SPPh2)N}2]

Abstract

The compound NH(SPMe₂)(SPPh₂) was prepared using a new method, i.e. the reaction between Li[HN(S)PPh₂] and Me₂P(S)Cl in a diethyl ether–n-hexane mixture. The complex [Co{(SPMe₂)(SPPh₂)N}₂] was obtained by the reaction of CoCl₂·6H₂O and K[(SPMe₂)(SPPh₂)N] in methanol. The crystal and molecular structure of both the free acid NH(SPMe₂)(SPPh₂) and its cobalt(II) complex [Co{(SPMe₂)(SPPh₂)₂N}₂] were determined using X-ray diffractometry. The acid exhibits an anti conformation of the sulfur atoms in the SPNPS system and dimeric pairs are formed in the crystal through N(1)–H(1)· · ·S(2a) [2.43(9) Å] hydrogen bonds, which involve only the sulfur atom of the SPPh₂ group of each molecule. The cobalt complex consists of discrete, monomeric molecules, with isobidentate ligands [average Co–S 2.32(1), average P–S 2.031(5) Å] and a distorted tetrahedral CoS₄ core (S–Co–S range 102.7–117.7°). The structures of both the free acid and its cobalt(II) derivative are discussed in relation with other bis(thiophosphinoyl)amines and metal complexes containing a CoS₄ core.