UC Riverside

Reactions between Mo(N-t-Bu)₂(CH₂-t-Bu)₂ or Mo(NAdamantyl)₂(CH₂CMe₂Ph)₂ and 3 equiv of HCl in the presence of 1 equiv of PPh₂Me yield Mo(NR)(CHR')(PPh₂Me)Cl₂ complexes, from which Mo(NR)(CHR')(PPh₂Me)(OAr)Cl complexes (OAr = a 2,6-terphenoxide) can be prepared. The Mo(NR)(CHR')(PPh₂Me)(OAr)Cl complexes were evaluated as cross-metathesis catalysts between cyclooctene and Z-1,2-dichloroethylene. The efficiencies of the test reaction for complexes in which OAr = OTPP, OHMT, OHIPT, or OHTBT (where OTPP is 2,3,5,6-tetraphenylphenoxide, OHMT is hexamethylterphenoxide, OHIPT is hexaisopropylterphenoxide, and OHTBT is hexa-t-butylterphenoxide) maximize when OAr is OHMT or OHIPT. Mo(N-t-Bu)(CH-t-Bu)(PPh₂Me)Cl₂ is essentially inactive for the reaction between cyclooctene and Z-1,2-dichloroethylene. X-ray structural studies were carried out on Mo(NAd)(CHCMe₂Ph)(PPh₂Me)Cl₂, Mo(N-t-Bu)(CH-t-Bu)(PPh₂Me)(OHMT)Cl, Mo(NAd)(CHCMe₂Ph)(Cl)(OHTBT)(PMe₃), and [Mo(NAd)(CHCMe₂Ph)(PMe₃)(Cl)]₂(μ-O), the product of the reaction between Mo(NAd)(CHCMe₂Ph)(Cl)(OHTBT)(PMe₃) and 0.5 equiv of water.