Halocarbonyltungsten(II) complexes containing tripodal tris(pyrazolyl)borate ligands

A detailed, systematic study of the halocarbonyl-w(II) complexes, LWX(CO)3 and LWX(CO)2 is presented. Convenient syntheses, physical and spectroscopic data and the X-ray crystal structure of the closely related complex L(super Pr)WI(CO)3 are reported. The 3:3:1 carbonyl-capped octahedral structure of L(super Pr)WI(CO)3 is compared with the structure of (HB(pz)3)MoBr(CO)3. Furthermore, the synthesis and characterization of NEt4L(super Br)W(CO)3, L(super Br)WBr-(CO)3, L(super Br)WBr(CO)2 and L(super Br)WB(MeCN)(CO) are examined to clarify observed ligand 4-bromination of NEt4(LW-(CO))3 by Br2.