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Tantalum reaction with ethylene

Despite dramatically different ancillary ligand sets, two distinct niobium and tantalum alkylidene systems provide isolable metallacyclobutanes upon reaction with ethylene. In one case, the tantalum aryldiamine pincer complex 148 reacts with ethylene to provide the cr-trimethylsilyltantalacyclobutane complex 149 (Equation 66) <19940M3259>. In a more comprehensive study, alkadiene-supported half-sandwich alkylidene complexes of both tantalum and niobium (the former isolable, the latter generated in situ) undergo [2+2] cycloaddition with a range of acyclic and cyclic alkenes, albeit in modest isolated yield (Equation 67). [Pg.598]

The Reaction of Tantalum Neopentylidene Hydride Complexes with Ethylene... [Pg.359]

A mononuclear tantalum-benzyne complex (121) has been prepared by thermolysis of 120 [Eq. (20)].14 An X-ray crystal structure was reported for 121. Bond lengths for the benzyne unit are given in Table III. Complex 121 exhibits a rich insertion chemistry similar to that of Ti, Zr, and Ru benzyne complexes. Insertion reactions of 121 with ethylene, 2-butyne, acetonitrile, and carbon dioxide give 122, 123, 124, and 125, respectively (Scheme 15). Diphenylacetylene does not couple with 121, presumably because of steric constraints. Reagents with acidic protons such as methanol or terminal alkynes cleave the Ta—C bond to give butyl isocyanide and carbon monoxide, but... [Pg.165]

It has been involved in many industrial explosions. Explodes on contact with aluminum + barium nitrate + potassium nitrate + water. Forms explosive mixtures with aluminum powder + titanium dioxide, ethylene glycol (240°C), cotton lint (245°C), furfural (270°C), lactose, metal powders (e.g., aluminum, iron, magnesium, molybdenum, nickel, tantalum, titanium), sulfur, titanium hydride. Reaction with ethanol + heat forms the explosive ethyl perchlorate. Violent reaction or ignition under the proper conditions with aluminum + aluminum fluoride, barium chromate + mngsten or titanium, boron + magnesium + silicone rubber, ferrocenium diammine-tetrakis(thiocyanato-N) chromate(l —), potassium hexacyanocobaltate(3—), A1 +... [Pg.1166]

The tantalum hydride (18) reacts reversibly with ethylene and at 70 °C dimerises ethylene selectively to 1-butene. The isomerization to 2-bu nes occurs only after the ethylene is consumed. The reaction (Scheme 15) is slow. An alternative mechanism via metallacycles could not be ruled out. ... [Pg.377]

See other pages where Tantalum reaction with ethylene is mentioned: [Pg.149]    [Pg.245]    [Pg.1042]    [Pg.353]    [Pg.118]    [Pg.30]    [Pg.200]    [Pg.38]    [Pg.200]    [Pg.611]    [Pg.2054]    [Pg.168]    [Pg.104]    [Pg.316]    [Pg.295]    [Pg.632]    [Pg.145]    [Pg.2450]    [Pg.208]    [Pg.211]    [Pg.1728]    [Pg.463]    [Pg.463]    [Pg.200]    [Pg.2054]    [Pg.103]    [Pg.763]    [Pg.229]   
See also in sourсe #XX -- [ Pg.2 , Pg.2 , Pg.11 , Pg.14 ]

See also in sourсe #XX -- [ Pg.2 , Pg.2 , Pg.11 ]



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Ethylene reaction with

Ethylene reactions

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