Trinuclear Zr2,Al .mu.-ketene complexes containing bridging ligands. Implications for transmetalation reactions and carbonyl reduction chemistry

Waymouth, Robert M.; Santarsiero, Bernard D.; Coots, R. J.; Bronikowski, Michael J.; Grubbs, Robert H.

doi:10.1021/ja00267a012

Cited by 52 publications

(10 citation statements)

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“…The −90 °C 13 C NMR spectrum of 5a contains separate resonances for the bridging (δ −0.8) and terminal (δ −5.2) methyl carbons. The μ-Me 1 J C - H value (133 Hz) is consistent with a large Al−C−Al angle, trigonal bipyramidal ( tbp ) geometry at C, and substantial sp 2 -C character in the C−H bonds . The terminal Me 1 J C - H value (118 Hz) is normal.…”

mentioning

confidence: 72%

Cationic Aluminum Alkyl Complexes Incorporating Aminotroponiminate Ligands

1998

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mentioning

confidence: 72%

Cationic Aluminum Alkyl Complexes Incorporating Aminotroponiminate Ligands

1998

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“…We believe the migration proceeds by means of a transient alkyl- or aryl-bridged species. A small number of complexes containing bridging alkyl groups have been isolated although, in general, they involve electron-deficient metal centers. , Addition of iodomethane to the ortho-metalated diplatinum complex [Pt 2 (μ-C 6 H 4 PPhCH 2 CH 2 PPh 2 ) 2 ] results in a species that may contain a bridging methyl group (alternatively, the methyl may undergo rapid migration between the two platinum centers, presumably by means of a bridging methyl complex) or aryl groups are also known.…”

Section: Resultsmentioning

confidence: 99%

Cleavage of Metal−Carbon Bonds in Hydride-Bridged Platinum and Palladium A-Frame Complexes

Anderson

1996

Organometallics

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The hydride-bridged A-frame complexes [RPt(μ-H)(μ-dppm)2PtR‘]PF6 and [RPt(μ-H)(μ-dppm)2PdR‘]PF6 react with HCl (generated by reaction of acetyl chloride with water) in acetone-d 6 solution by cleavage of one of the metal−carbon bonds. In the diplatinum systems the relative rates of Pt−C bond cleavage decrease in the order Me > Et > Ph, resulting in a single product in each case. For the heterometallic complexes reaction is faster at palladium, but mixtures of [RPt(μ-H)(μ-dppm)2PdCl]PF6 and [ClPt(μ-H)(μ-dppm)2PdR‘]PF6 result in several instances. Further reaction of these with HCl and/or CCl4 generates the chloride-bridged species [RPt(μ-Cl)(μ-dppm)2PdCl]PF6, formed, in some cases, by migration of the organic group from palladium to platinum. These complexes have been prepared also by reaction of [PtR(dppm-PP)(dppm-P)]PF6 with [PdCl2(cod)]. The [RPt(μ-Cl)(μ-dppm)2PdCl]PF6 complexes are fluxional at 298 K, although the motion may be arrested slightly below ambient temperature. A mechanism involving reversible bridge opening is proposed to account for the fluxional behavior.

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“… 86 , 120 , 146 – 153 A ketene analogue is also known which incorporates an oxycyclopropane ring. 154 The structures of 84–87 are distorted to accommodate additional intramolecular binding interactions. Calculations have shown that electron donation from the bridging Zr–C bond to the Lewis acidic main group centre plays a key role in the stabilisation of these species ( 82 ) and explains the unusual geometry at the bridging carbon.…”

Section: Multiply-bridged Complexes (Tm–h N –Mmentioning

confidence: 99%