Tridentate phosphine ligands with novel linker-units

Abstract

The synthesis of two novel types of tripodal phosphine ligands containing vinyl and alkynyl linker functions in their ligand backbones are reported. Using pentaerythritol (1) as the starting material the functionalized phosphines H2CCH–CH2OCH2C(CH2PPh2)3 (6), Me3SiCC–CH2OCH2C(CH2PPh2)3 (10) and HCC–CH2OCH2C(CH2PPh2)3 (11) were obtained in good yield in 4–5-step syntheses. H2CCH–CH2OCH2C(CH2PPh2)3 (6) and the silyl protected alkinyl derivative (CH3)3Si–CC–CH2OCH2C(CH2PPh2)3 (10) were reacted with one molar equivalent of [Mo(CO)3(MeCN)3] to yield the yellow-brown, air stable triphosphine–molybdenum complexes [{H2CCH–CH2OCH2C(CH2PPh2)3}Mo(CO)3] (12) and [{(CH3)3Si–CC–CH2OCH2C(CH2PPh2)3}Mo(CO)3] (13) the latter of which was characterized by X-ray diffraction.