.alpha.-Elimination Can Be Faster than .beta.-Elimination in d2 Alkyl Complexes of Molybdenum and Tungsten That Contain the Trimethylsilyl-Substituted Triamidoamine Ligand

Shape and Symmetry of Heptacoordinate Transition‐Metal Complexes: Structural Trends

“…An alternative description of such a structure would be an FeP 3 Sn tetrahedron (actually this core is close to the tetrahedron, with S(T d ) 0.85), with three faces capped by hydrides (Figure 6 b). 3) A similar CO is found (Figure 6 c) for the W atom in [WH 3 (N{EtNSiMe 3 } 3 )], [40,41] but in this case the hydrides occupy the basal face (Table 3). 4) An approximate 5:2 geometry would describe the unusual coordination geometry of Ag (S(C 5 ) 1.84 for Ag and the five basal ligands) in a complex with an antibiotic [42] (Figure 6 d), and in an Table 2.…”

Highlights in the Renaissance of Amidometal Chemistry

“…If 64 is allowed to react with cyclopentyllithium a,a-elimination is blocked and the reaction remains at the stage of the carbene ± hydrido complex 66 (Scheme 52). [223] Product 66 is unstable and changes into the paramagnetic compound 67 with the loss of cyclopentene. The reaction of 64 with a-D-cyclopentyllithium at low temperatures gives the kinetically preferred intermediate 66 with ªdeuterido ligandº, which confirms that in this system a-cleavage occurs faster than b-elimination under the given conditions.…”

“…[229] Ten years before the existence of the MP species had already been discussed. [230] The tendency of compound 60 to react with N 2 [212] or N 2 O [211] by NÀN bond cleavage to form the nitrido complex and the affinity of the [(TMSN 3 N)W] fragment for the spontaneous formation of metal ± carbon triple bonds [223,219] suggest that both systems are set up for the stabilization of a terminal P 1 ligand.…”

Non-oxidative coupling of methane catalysed by supported tungsten hydride onto alumina and silica–alumina in classical and H2 permeable membrane fixed-bed reactors

“…These observations indicate that the methyl species formed after activation of CH 4 onto W-H@SiO 2 -Al 2 O 3 , leads to a partial evolution of a mixture of unsaturated surface species, such as [W = CH 2 ] and [WRCH], probably by subsequent a-H abstraction and a-H elimination, respectively (Scheme S1, ESIw). 17,30,31 The 1 H NMR spectrum is provided in the ESI (Fig. S4).w The signal at À4 ppm is attributed to methyl carbon attached to silicon ((Si-Me) or (Si(H)Me)) originated from the transfer of W-Me.…”