Unusual mixed-metal carbonate-bridged complexes via oxidation of a carbonyl ligand in [RhM(CO)4(Ph2PCH2PPh2)2] (M = Mn, Re) and [IrRe(CO)5(Ph2PCH2PPh2)2]

Antonelli, David M.; Cowie, Martin

doi:10.1021/om00053a020

Cited by 10 publications

(4 citation statements)

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“…In addition, the bridging mode of the carbonyl group in the solid state was established by solid-state 13 C NMR spectral results (vide infra). A similar disorder has been observed in the X-ray structure analyses for [RhIr(CH 3 )(CO) 3 (dppm) 2 ][CF 3 SO 3 ],2b [Ir 2 (CH 3 )(CO) 2 (dppm) 2 ][[CF 3 SO 3 ],1b [RhMn(CO) 3 (μ-CO 3 )(dppm) 2 ], and [RhM(CO) 4 (dppm) 2 ] (M = Mn, Re) . Location of the dppm atoms in 2 proceeded well with no evidence of disorder.…”

Section: Methodssupporting

confidence: 70%

Heterobinuclear Methyl Complexes of Rhodium/Iridium: Reactivity with Nucleophiles and Subsequent Ligand Rearrangements

1999

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Reaction of [RhIr(CH3)(CO)3(dppm)2][CF3SO3] (1) (dppm = Ph2PCH2PPh2) with several phosphines and phosphites yields the carbonyl-substitution products [RhIr(CH3)(PR3)(CO)2(dppm)2][CF3SO3] (4), in which the added phosphine and the methyl ligands are coordinated to Ir. At −80 °C an intermediate in this reaction, [RhIr(CH3)(PR3)(CO)3(dppm)2][CF3SO3] (3), is observed in which the monodentate PR3 group is bound to Rh. Similar reactions with the dicarbonyl compound [RhIr(CH3)(CO)2(dppm)2][CF3SO3] (2) suggests that attack occurs directly at Ir in this case. The structure of 2 is subtly different in solution and in the solid state, having the carbonyls both terminally bound (one to each metal) in solution, but having one bridging in the solid. Addition of cyanide and hydride ligands to 2 yields the neutral products [RhIr(CH3)X(CO)2(dppm)2] (X = CN, H), in which both anionic ligands (X and CH3) are bound to Ir. The hydrido species is unstable, eliminating methane at ambient temperature. Addition of iodide ion to 2 yields the related neutral species, which has the methyl group on Rh and the iodide ligand on Ir. The X-ray structures of compounds 2 and 4a (PR3 = PMe3) are reported. Compound 2 has a terminal carbonyl on Rh, essentially opposite the Rh−Ir bond, the methyl group in a similar position on Ir, and a semibridging carbonyl, which is more tightly bound to Ir. The geometry of 4a has a square-planar Rh center in which Ir occupies one of the coordination sites opposite a carbonyl, and an octahedral Ir center in which the PMe3 group is opposite the Ir−Rh bond, and the methyl group is opposite the second carbonyl. The crowding at Ir upon addition of the PMe3 group shows up in a number of distortions within the molecule.

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Section: Methodssupporting

confidence: 70%

Heterobinuclear Methyl Complexes of Rhodium/Iridium: Reactivity with Nucleophiles and Subsequent Ligand Rearrangements

1999

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“…The other mode is less symmetrical in the sense that one of the oxygen atoms, O(4), is tilted toward the second scandium center such that it forms a weak interaction and bridges the metal centers. The Sc–O(4) bond distance of 2.110(3)Å is similar to the others in the molecule, but the distance to the second scandium is substantially longer (Sc′–O(4), 2.337(3)Å) . As a consequence of this weaker interaction, the scandium centers are seven coordinate, with a distorted pentagonal-bipyramidal geometry in which the atoms of the symmetrically bridging carboxylato ligands, O(5) and O(6), occupy the apical sites.…”

Section: Resultsmentioning

confidence: 71%

“…The Sc−O(4) bond distance of 2.110(3)Å is similar to the others in the molecule, but the distance to the second scandium is substantially longer (Sc′− O(4), 2.337(3)Å). 45 As a consequence of this weaker interaction, the scandium centers are seven coordinate, with a distorted pentagonal-bipyramidal geometry in which the atoms of the symmetrically bridging carboxylato ligands, O(5) and O(6), occupy the apical sites.…”

Section: ■ Introductionmentioning

confidence: 99%

Reactivity of Scandium β-Diketiminate Alkyl Complexes with Carbon Dioxide

et al. 2012

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The reactions of two highly air- and moisture-sensitive scandium bis(alkyls) supported by a bulky β-diketiminato (nacnac) ligand with carbon dioxide are described. [κ2-ArNC( t Bu)CHC( t Bu)NAr]ScR2 (Ar = 2,6- i Pr2C6H3; R = CH3, 1a; R = CH2SiMe3, 1b) react rapidly with CO2 to give mixtures of mono- and bis(carboxylato) insertion products 2a/2b and 3a/3b depending on the stoichiometry and conditions of the reaction. Compound 2a (R = CH3) is a dimeric complex with bridging acetato groups, as determined by X-ray crystallography. These compounds were characterized by NMR spectroscopy, and 3a could be isolated in pure form. Treatment of these compounds with excess CO2 resulted in addition to the central carbon of the Sc(nacnac) six-membered ring and displacement of the nitrogen donors to yield dimeric scandium carboxylates 4a/4b; compound 4b was characterized by X-ray crystallography. Reactions of the nacnac scandium cations formed upon abstraction of one or two methides from 1a using B(C6F5)3 with CO2 were also explored. Although the products were qualitatively more thermally robust, eventually ligand displacement occurred in these cationic acetato complexes as well. Nevertheless, insertion products were characterizable in solution using NMR spectroscopy. Overall, this study shows the facility with which CO2 is taken up by scandium alkyls but that the nacnac ligand framework is too reactive to support chemistry aimed at catalytic conversion of CO2 into other products.

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“…In the majority of bimetallic catalysts little is understood about the functions of the different metals in the transformations of interest. We have therefore been studying a range of mixed-metal complexes with the goal of developing a better understanding of the roles of the different metals in substrate transformation; − of particular relevance to FT chemistry are those complexes incorporating combinations of group 8 and 9 metals. ,,,,,− ,− The most promising system studied by us to date is [RhOs(CO) 4 (dppm) 2 ][X] (dppm = μ-Ph 2 PCH 2 PPh 2 , X = anion), which can incorporate between one and four methylene units (derived from diazomethane), yielding methylene-bridged ( A ), allyl/methyl ( B ), or butanediyl ( C ) fragments on the metals, as shown in Scheme . The high FT activity of Ru, as well as the rich chemistry of diruthenium complexes in carbon−carbon bond formation, led us to extend the above Rh/Os chemistry to include the Rh/Ru combination of metals, and our preliminary findings on this system are reported herein, as are comparisons with the above Rh/Os system 21 and the related Ir/Ru system …”

Section: Introductionmentioning

confidence: 99%

Methylene-Bridged Complexes of Rhodium/Ruthenium as Models for Bimetallic Fischer−Tropsch Catalysts: Comparisons with the Rh/Os and Ir/Ru Analogues

et al. 2002

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The cationic heterobinuclear complex [RhRu(CO) 3 (µ-H) 2 (dppm) 2 ][X] (1) is prepared by protonation of the monohydride species [RhRu(CO) 3 (µ-H)(dppm) 2 ] (dppm ) µ-Ph 2 PCH 2 PPh 2 ; X -) BF 4 -, CF 3 SO 3 -). Treatment of 1 with carbon monoxide affords the tetracarbonyl complex ion [RhRu(CO) 4 (dppm) 2 ][X] (2), which yields the methylene-bridged product [RhRu(CO) 4 (µ-CH) 2 (dppm) 2 ][X] (3), upon treatment with excess diazomethane at -78 °C. Reaction of 3 with trimethylamine-N-oxide results in CO removal, affording the methylene-bridged tricarbonyl species [RhRu(CO) 3 (µ-CH) 2 (dppm) 2 ][X] (4). Although compound 3 is unreactive toward further treatment with CH 2 N 2 , compound 4 reacts readily with diazomethane, yielding a mixture of uncharacterized products. Compounds 3 and 4 react with PMe 3 to yield [RhRu(PMe 3 )(CO) 3 (µ-CH) 2 (dppm) 2 ][X] (5), in which coordination of PMe 3 at the unsaturated Rh center occurs. The structures of compounds 2, 3, and 5 have been determined by X-ray methods. Comparisons of the reactivity of compound 3 with that of the analogous Ir/Ru and Rh/Os complexes toward diazomethane are presented.

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Unusual mixed-metal carbonate-bridged complexes via oxidation of a carbonyl ligand in [RhM(CO)4(Ph2PCH2PPh2)2] (M = Mn, Re) and [IrRe(CO)5(Ph2PCH2PPh2)2]

Cited by 10 publications

References 1 publication

Heterobinuclear Methyl Complexes of Rhodium/Iridium: Reactivity with Nucleophiles and Subsequent Ligand Rearrangements

Heterobinuclear Methyl Complexes of Rhodium/Iridium: Reactivity with Nucleophiles and Subsequent Ligand Rearrangements

Reactivity of Scandium β-Diketiminate Alkyl Complexes with Carbon Dioxide

Methylene-Bridged Complexes of Rhodium/Ruthenium as Models for Bimetallic Fischer−Tropsch Catalysts: Comparisons with the Rh/Os and Ir/Ru Analogues

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