Addition of diphenyldiazomethane to hexa-alkoxydimolybdenum(MM) compounds: characterization of Mo₂(OPrⁱ)₆(N₂CPh₂)₂(pyridine) by X-ray crystallography

The Butterfly Dimer [(tBu3SiO)Cr]2(μ-OSitBu3)2 and Its Oxidative Cleavage to (tBu3SiO)2Cr(N−NCPh2)2 and (tBu3SiO)2CrN(2,6-Ph2-C6H3)

“…Given the rates, regardless of mechanism, it is certainly reasonable to consider 1 2 as a source of "(silox) 2 Cr (1) ing parameters to 2 was observed by Chisholm and coworkers. 39 The dinuclear complex, [( i PrO) 2 42 What is unique about the conversion of 1 2 to 2 upon addition of Ph 2 CNN is the conversion of Cr(II) to Cr(VI), but this is mostly a consequence of the lack of chromous reagents that could accommodate two of the diphenylmethylidenehydrazido ligands.…”

Cationic Tungsten Alkylidyne N‐Heterocyclic Carbene Complexes: Synthesis and Reactivity in Alkyne Metathesis

“…In addition to a bridging chloride, the molybdenum atoms were also bridged by one of the silyloxide ligands. Other ditungstatetrahedrane structures, which derived from alkylidynes or W≡W species were published by the groups of Fischer and Chisholm . Especially interesting are Chisholm's complexes that are generated by the addition of alkynes to W 2 (OR) 6 and form ditungstatetrahedranes instead of the expected alkylidyne complexes, as observed by Schrock et al by scission of the W≡W bond .…”

“…These ditungstatetrahedranes are in equilibrium with the alkylidyne complexes. [21b], [21c] For W19 neither an equilibrium with W18 nor any reactivity in test reactions with 1‐phenyl‐1‐propyne ( S1 ) was observed. The formation of W19 with loss of the alkylidyne moiety during transformation to a cationic complex and the identification of the dimetallatetrahedrane by Fürstner et al as one decomposition product of their catalyst, leads us to believe that bimolecular decomposition might indeed be a possible decomposition pathway for cationic alkylidyne NHC complexes.…”

“…In Chisholm's complex derived from the reaction of W 2 (O t Bu) 6 and acetylene, a pyridine also coordinates to only one tungsten center, but there are no substantial differences in W–C‐bond lengths (211.9(9) and 209.5(9) pm for the two W center without pyridine vs. 209.0(10) and 209.3(9) pm for the tungsten center with pyridine). [21b] The W–W bond in W19 (267.09 pm) is comparable to the one in Chisholm's complex (266.5(2) pm) and longer than the Mo–Mo bond in Fürstner's dimolybdatetrahedrane (256.18(3) pm), whereas the C–C bond in the ditungstatetrahedrane core of W19 with 139.2(5) pm is similar to the one in Fürstner's dimolybdatetrahedrane complex (139.0(3) pm) and shorter than in Chisholm's ditungstatetrahedrane (144.1(14) pm), (Figure ) ,. [21b]…”

Metal-metal multiple bonds in dinuclear clusters

“…All of the isolable simple alkyne addition products are reactive toward further alkyne molecules to give new products in which two or more alkyne molecules have been coupled [163][164][165]. Two of these are shown in Fig.…”