Syntheses of Molybdenum(VI) Imido Alkylidene Complexes That Contain a Bidentate Dithiolate Ligand

摘要

Zn(DCTC) (DCTC = 3,6-dichlorodithiacatecholate) reacts with Mo(NAd)(CHCMe2Ph)Cl-2 (PPh2Me) (Ad = 1-adamantyl) to give Mo(NAd)(CHCMe2Ph)(DCTC)(PPh2Me). The reactions between Zn(DCTC) and Mo(NAd)(CH-t-Bu)(OTf)(2) (dme) or Mo(NAr)(CHCMe2Ph)(OTf)(2)(dme) (Ar = 2,6-i-Pr2C6H3 ; OTf = triflate; dme = 1,2-dimethoxyethane) produce [Mo(NAd)(CH-t-Bu)(DCTC)](2) and [Mo(NAr)(CHCMe2Ph)(DCTC)](2), respectively. Complexes that contain a 3,3',5,5'-tetrasubstituted dithiabiphenolate were prepared in a reaction between Mo(NAr)(CHCMe2 Ph)(Me(2)pyr)(2) (Me(2)pyr = 2,5-dimethylpyrrolide) and the 3,3',5,5'-tetrasubstituted dithiabiphenols, (3,3',5,5'-tetrachlorodithiabiphenol (H2Cl4S2), 3,3',5,5'-tetrabromodithiabiphenol (H2Br4S2 ), and 3,3',5,5'tetra-t-Bu-dithiabiphenol (H2Bu4S2)). The isolated complexes include Mo(NAr)(CHCMe2Ph) (Cl4S2) (pyridine), Mo(NAr) (CHCMe2Ph) (Br4S2) (pyridine), Mo(NAr)(CHCMe2Ph)(Bu4S2)(PMe3), and [Mo(NAr)(CHCMe2Ph)(Cl4S2)](2) . Only the dithiabiphenolate derivatives (in the presence of B(C6F5)(3)) show activity for the metathesis of 1-decene, and although that reaction is limited by a sensitivity of the alkylidene complexes to ethylene, as suggested by the reaction between ethylene and Mo(NAr)(CHCMe2Ph)(Bu4S2) to give the ethylene complex, Mo(NAr)(C2H4)(Bu4S2). Mo(NAr)(C2H4 )(Bu4S2) was unstable with respect to loss of ethylene and formation of an ethylene-free dimer. Mo(NAd)(CHCMe2Ph)(DCTC)(PPh2Me), [Mo(NAr)(CHCMe2Ph)(DCTC)](2), and [Mo(NAr)(CHCMe2Ph)(Cl4S2)](2) were characterized crystallographically.