The synthesis and characterization of cobalt complexes with diphosphorus–sulphur and –selenium cyclic units as trihapto ligands. X-Ray crystal structures of [Co{CMe(CH2PPh2)3}(P2X)]BF4·C6H6(X = S or Se)

Abstract

The reaction of Co(BF₄)₂·6H₂O with P₄S₃ or P₄Se₃ in the presence of 1,1,1-tris(diphenylphosphino methyl)ethane (tppme) yielded complexes [Co(tppme)(P₂X)]BF₄·C₆H₆[X = S (1) or Se (2)]. The molecular structures of the complexes have been determined by single-crystal X-ray diffraction methods. Both compounds crystallize in the monoclinic space group P2₁/n with Z= 4 and unit-cell dimensions: a= 17.193(7), b= 20.164(8), c= 13.136(7)Å, β= 103.35(8)°[for (1)]; and a= 17.049(8), b= 20.119(9), c= 13.188(8)Å, β= 102.74(8)°[for (2)]. The metal atom in both compounds is in a six-co-ordinate environment formed by the tppme P atoms and by the atoms of the heterocyclic P₂S or P₂Se unit, as shown by the crystallographic investigations and by ³¹P n.m.r. studies.