Tungsten imido complex

Imido Complexes. The reaction of azitidines with tungsten(II) complexes leads to the formation of tungsten(IV) imido complexes (332) ... 

Inter- and intramolecular (cyclometallation) reactions of this type have been ob-.served, for instance, with titanium [408,505,683-685], hafnium [411], tantalum [426,686,687], tungsten [418,542], and ruthenium complexes [688], Not only carbene complexes but also imido complexes L M=NR of, e.g., zirconium [689,690], vanadium [691], tantalum [692], or tungsten [693] undergo C-H insertion with unactivated alkanes and arenes. Some illustrative examples are sketched in Figure 3.37. No applications in organic synthesis have yet been found for these mechanistically interesting processes. 

Schrock and coworkers have generated and tested more than forty molybdenum and tungsten imido complexes with pincer iridium complex for AM [59]. In general, tungsten complexes perform better than molybdenum complexes, presumably due to... 

Imidazolium ligands, in Rh complexes, 7, 126 Imidazolium salts iridium binding, 7, 349 in silver(I) carbene synthesis, 2, 206 Imidazol-2-ylidene carbenes, with tungsten carbonyls, 5, 678 (Imidazol-2-ylidene)gold(I) complexes, preparation, 2, 289 Imidazopyridine, in trinuclear Ru and Os clusters, 6, 727 Imidazo[l,2-a]-pyridines, iodo-substituted, in Grignard reagent preparation, 9, 37—38 Imido alkyl complexes, with tantalum, 5, 118—120 Imido-amido half-sandwich compounds, with tantalum, 5,183 /13-Imido clusters, with trinuclear Ru clusters, 6, 733 Imido complexes with bis-Gp Ti, 4, 579 with monoalkyl Ti(IV), 4, 336 with mono-Gp Ti(IV), 4, 419 with Ru half-sandwiches, 6, 519—520 with tantalum, 5, 110 with titanium(IV) dialkyls, 4, 352 with titanocenes, 4, 566 with tungsten... 

The metathesis of symmetrical aliphatic carbodiimides is also catalyzed by tungsten imido complexes above 140 Other carbodiimide metathesis catalysts include Cr(ll)/Si02/ iminophosphoranes, imido circonocenes, guanidine supported titanium complexes and group 14 amide complexes. ... 

Studies of the chemistry of phenylimido rhenium complexes have normally employed Re(NPh)Cl3(PPh3)2 as the starting material because of its easy preparation from aniline and the readily available compound ReOClj(PPh3)2. Tungsten imido complexes cannot be prepared similarly. The lack of good preparative methods leading to suitable starting materials has limited studies with this metal. 

Extensive studies on potential intermediates, kinetic isotope effects, and selectivities have been conducted on the shylamido compoimds. Studies with tungsten alkyl amido complexes have shown that formation of an alkane complex precedes C-H bond cleavage by these d° imido complexes, just as it precedes oxidative addition and a-bond metathesis. ... 

The development of well-defined ROMP initiators has expanded the scope of the metathesis reaction, permitting the controlled polymerisation of highly functionalised monomers. Schrock s well-defined olefin metathesis initiators became available in the mid 1980s and they were based on alkoxy imido complexes of tungsten and molybdenum of general... 

Hayton TW, BonceUaJM, Scott BL, Abboud KA, Mills RC. Coupling of an aldehyde or ketone to pyridine mediated by a tungsten imido complex. Inorg Chem. 2005 44 9506-9517. 

TUNGSTEN OXYTETRACHLORIDE AND (ACETONITRILE)TETRACHLOROTUNGSTEN IMIDO COMPLEXES... 

Tungsten Oxytetrachloride and (Acetonitrile)tetrachlorotungsten Imido Complexes 139... 

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