Synthesis of Molybdenum(VI) Neopentylidene Neopentylidyne Complexes
- Author(s): Tafazolian, H
- Schrock, RR
- Müller, P
- et al.
Published Web Locationhttps://doi.org/10.1021/acs.organomet.9b00412
Mo(C-t-Bu)(CH-t-Bu)(Cl)(PMe Ph) (1) was prepared as off-white crystals in 26% yield through addition of 2.5 equiv of Mg(CH -t-Bu) to Mo(O)[OC(CF ) ] in diethyl ether followed by 3 equiv of PMe Ph and a workup that includes dichloromethane (the source of Cl). Compound 1 is largely a syn isomer initially that equilibrates to give approximately a 1:1 mixture of syn and anti isomers within 1-2 h. Compound 1 reacts with Li(3,5-dimethylpyrrolide) to give Mo(C-t-Bu)(CH-t-Bu)(η -Me Pyr)(PMe Ph) (2a) as a pale yellow solid in 76% yield, and 2a reacts with Ph SiOH to give a mixture of syn and anti Mo(C-t-Bu)(CH-t-Bu)(OSiPh )(PMe Ph) (3a) in 84% yield. All three compounds tend to lose PMe Ph to give 14e monophosphine complexes with the formulas Mo(C-t-Bu)(CH-t-Bu)(X)(PMe Ph) (X = Cl, Me Pyr, or OSiPh ), none of which could be isolated. X-ray studies show the structures of 1, 2a, and 3a to be analogous with τ values of 0.45, 0.53, and 0.69, respectively. 2 2 2 2 3 3 4 2 2 2 2 3 3 2 2 2 2 2 3 1