259267-55-5

Upstream product

• 75-77-4 chloro-trimethyl-silane 
• 110-71-4 1,2-dimethoxyethane 
• 5509-65-9 2,6-difluoroaniline 

Downstream Products

• 259267-63-5 [Mo(NC₆H₃F₂)2(S₂CN(C₂H₅)2)2] 

Relevant academic research and scientific papers

Origin and Use of Hydroxyl Group Tolerance in Cationic Molybdenum Imido Alkylidene N-Heterocyclic Carbene Catalysts

The origin of hydroxyl group tolerance in neutral and especially cationic molybdenum imido alkylidene N-heterocyclic carbene (NHC) complexes has been investigated. A wide range of catalysts was prepared and tested. Most cationic complexes can be handled in air without difficulty and display an unprecedented stability towards water and alcohols. NHC complexes were successfully used with substrates containing the hydroxyl functionality in acyclic diene metathesis polymerization, homo-, cross and ring-opening cross metathesis reactions. The catalysts remain active even in 2-PrOH and are applicable in ring-opening metathesis polymerization and alkene homometathesis using alcohols as solvent. The use of weakly basic bidentate, hemilabile anionic ligands such as triflate or pentafluorobenzoate and weakly basic aromatic imido ligands in combination with a sterically demanding 1,3-dimesitylimidazol-2-ylidene NHC ligand was found essential for reactive and yet robust catalysts.

Bent vs. linear imido ligation at the octahedral molybdenum(VI) dithiocarbamate stabilised centre

Molybdenum(VI) bis(imido) complexes [Mo(NR)2(S2CNEt2)2] 3a-3p have been prepared via two synthetic routes and their structures investigated. Thermolysis of [MoO2(S2CNEt2)2] 1 with 2,6-disubstituted aryl isocyanates affords air-stable bis(imido) complexes 3i-3m in high yields after column chromatography, a route which fails for sterically less demanding isocyanates. A more general preparation involves room temperature addition of two equivalents of [S2CNEt2]- to the labile bis(imido) complexes [Mo(NR)2Cl2(dme)] 2a-2p (dme = 1,2-dimethoxyethane) to afford 3a-3p in high yields. In this manner related complexes [Mo(NR)2(S2CNMe2)2] 4 (R = Ph or But) and [Mo(NPh)2(S2PPh2)2] 5a have also been prepared. Structural and spectroscopic studies have been carried out in order to determine the degree of bending of the imido ligands. Six complexes have been characterised by X-ray crystallography. In all cases one of the imido ligands is linear (Mo-N-C ≥ 160°), while the angle at the second is dependent upon the nature of R and ranges from 180 to 139°. Solid-state 13C CPMAS spectroscopy reveals that the difference in bond angles at the two nitrogen centres (Δ°) correlates closely with the difference in chemical shifts of the ipso-carbon atoms (Δδ). This then has been used to probe the relative bond angles at nitrogen for non-crystallographically characterised complexes. In solution even at low temperatures both imido ligands are equivalent indicating a rapid interconversion between linear and bent bonding modes. The Royal Society of Chemistry 1999.