Design, Synthesis, and Chemistry of Sterically Nondemanding Primary Bisphosphines¹

Design and synthesis of chelating bisphosphines functionalized with the smallest chemical unit “H” on the PIII centers ((PH2CH2)2CHCH2NHPh (4) and (PH2CH2)2CHCONHPh (5)) are described. Studies demonstrating that no bulky chemical substituents are necessary to offer thermal/oxidative stability to the −PH2 groups in 4 and 5 are described. The H atoms around the PIII centers in 5 (or 4) concur limited/no steric influence, but yet the phosphines manifest high nucleophilicity to coordinate strongly with W(0) and Re(I). The studies include synthesis and X-ray structural characterization of an air-stable primary bisphosphine (5) and its transition-metal chemistry with W(CO)6 and Re(CO)5Br to produce the complexes (η2-(PH2CH2)2CHCONHPh)W(CO)4 (6) and (η2-(PH2CH2)2CHCONHPh)Re(CO)3Br (7), respectively.