Synthesis and characterization of novel neutral σ-alkynylcarbonylnitrosyl molybdenum(0) and tungsten(0) complexes. Crystal structure of [Mo(C≡CnPR)(CO) 2(dppe)(NO)] [dppe = 1,2-bis(diphenylphosphino) ethane]

Article abstract of DOI:10.1016/0022-328X(95)06023-P

σ-Alkynyl dicarbonyl complexes [M(C≡CR)(CO)₂(dppe)(NO)] (M = Mo, R = H, ^tBu, ⁿPr, ⁱPr, Ph, CH₂OCH₃, SiMe₃; M = W, R = H, ^tBu, ⁿPr) have been prepared by reaction of mer-[M(CO)₃(dppe)(NO)][BF₄] with an equimolar amount of the acetylide salt M′C≡CR (M′ = Li, Na). The complexes [M(CO)₂(NCMe)(dppe)(NO)] [BF₄] (M = Mo, W) and [Mo(CO)(NCMe)₂(dppe)(NO)][BF4] obtained by reaction of mer-[M(CO)₃(dppe)(NO)][BF₄] with acetonitrile are suitable precursors for the synthesis of the complexes [M(CO)₂(dppe)(PR₃)(NO)][BF4] (M = Mo, W, PR₃ = PMe₃, PMe₂Ph) and [M(CO)(NCMe)(dppe)(PR₃)(NO)][BF₄] (PR₃ = PMe₂Ph, PPh₃, P(OPh)₃). The reaction of [Mo(CO)₂(NCMe)(dppe)(NO)][BF₄] with NaS(o--C₆H₄Me) yields the neutral complex [Mo{S(o-C₆H₄Me)}(CO)₂(dppe)(NO)]. The crystal structure of [Mo(C≡CⁿPr)(CO)₂(dppe)(NO)] has been determined by X-ray diffraction methods. The Mo atom displays a distorted octahedral coordination involving the N and C atoms of the nitrosyl and the alkynyl ligands in the apical positions and the P atoms from the dppe chelating ligand and two C atoms from terminal carbonyl groups in the equatorial positions.