Hybrid dibismuthines and distibines as ligands towards transition metal carbonyls

Abstract

The hybrid dibismuthines O(CH₂CH₂BiPh₂)₂ and MeN(CH₂-2-C₆H₄BiPh₂)₂ react with [M(CO)₅(thf)] (M = Cr or W) to form [{M(CO)₅}₂{O(CH₂CH₂BiPh₂)₂}] and [{Cr(CO)₅}₂{MeN(CH₂-2-C₆H₄BiPh₂)₂}] containing bridging bidentate (Bi₂) coordination. The unsymmetrical tertiary bismuthine complexes [M(CO)₅{BiPh₂(o-C₆H₄OMe)}] are also described. Depending upon the molar ratio, the hybrid distibines O(CH₂CH₂SbMe₂)₂ and MeN(CH₂-2-C₆H₄SbMe₂)₂ react with [M(CO)₅(thf)] to give the pentacarbonyl complexes [{M(CO)₅}₂{O(CH₂CH₂SbMe₂)₂}] and [{Cr(CO)₅}₂{MeN(CH₂-2-C₆H₄SbMe₂)₂}] or tetracarbonyls cis-[M(CO)₄{O(CH₂CH₂SbMe₂)₂}] and cis-[M(CO)₄{MeN(CH₂-2-C₆H₄SbMe₂)₂}]. The latter can also be obtained from [Cr(CO)₄(nbd)] or [W(CO)₄(pip)₂], and contain chelating bidentates (Sb₂-coordinated) as determined crystallographically. S(CH₂-2-C₆H₄SbMe₂)₂ coordinates as a tridentate (SSb₂) in fac-[M(CO)₃{S(CH₂-2-C₆H₄SbMe₂)₂}] (M = Cr or Mo) and fac-[Mn(CO)₃{S(CH₂-2-C₆H₄SbMe₂)₂}][CF₃SO₃]. Fac-[Mn(CO)₃{MeN(CH₂-2-C₆H₄SbMe₂)₂}][CF₃SO₃] contains NSb₂-coordinated ligand in the solid state, but in solution a second species, Sb₂-coordinated and with a κ¹-CF₃SO₃ replacing the coordinated amine is also evident. X-ray crystal structures were also determined for fac-[Cr(CO)₃{S(CH₂-2-C₆H₄SbMe₂)₂}], fac-[Mn(CO)₃{S(CH₂-2-C₆H₄SbMe₂)₂}][CF₃SO₃] and fac-[Mn(CO)₃{MeN(CH₂-2-C₆H₄SbMe₂)₂}] [CF₃SO₃]. Hypervalent N⋯Sb interactions are present in cis-[M(CO)₄{MeN(CH₂-2-C₆H₄SbMe₂)₂}] (M = Mo or W), but absent for M = Cr.