Structures of transition-metal hydride complexes

Bau, Robert; Teller, Raymond G.; Kirtley, Stephen W.; Koetzle, Thomas F.

doi:10.1021/ar50137a003

Cited by 212 publications

(105 citation statements)

References 43 publications

(4 reference statements)

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“…1.75(7) A) are in good agreement with each other and are in the range normally observed for hydrides which bridge second and third row group VIU metals (15,16). The angle at the bridging hydride is 105(4)".…”

Section: Description Of Structure and Discussionsupporting

confidence: 87%

The structure of [Ir₂(CO)₂(μ-H)(μ-CO)(Ph₂PCH₂PPh₂)₂][BF₄] and comparisons with its rhodium analogue and other related doubly bridged A-frames

Sutherland¹,

Cowie²

1986

Can. J. Chem.

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. 64, 464 (1986).The structure of [Ir2(CO)2(p-H)(p-CO)(DPM)2][BF4] (DPM=Ph2PCH2PPh2) has been determined~crystallographically. It crystallizes in the monoclinic space group P2' /n (a = 13.7740(6) A, b = 15.277(2) A, c = 23.581 (2) A, P = 97.015(5)", V = 4924.9 A3, Z =4) and on the basis of 6628 unique observations and variation of 272 parameters, the structure converged to R = 0.031 and R,, = 0.043. This metal-metal bonded complex is similar to its rhodium analogue, having the two essentially identical Ir centres bridged by the carbonyl, hydride, and two diphosphine ligands. The major difference between this compound and the rhodium species (in the solid state) relates to the orientation of the phenyl groups of the diphosphine ligands; in the iridium complex four of these groups block the sites adjacent to the bridging hydride ligand, whereas these sites are relatively unobstructed in the rhodium analogue. This difference may result in different coordination sites for substrate molecules and therefore in different chemistry. IntroductionWe have recently shown (1) that catalysis of the water-gas shift (WGS) reaction, by complexes containing two metal centres, can be effectively modelled by using DPM-bridged (DPM = Ph2PCH2PPh2), hydrido, and hydroxy complexes of iridium. In particular, the observation of [Ir2(C0)2(pH)(k-CO)(DPMh]+ in our WGS cycle prompted us to suggest that this cycle could serve as a model for the one in which the rhodium analogue, [Rh2(C0)2(pH)(pCO)(DPM)2]

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Section: Description Of Structure and Discussionsupporting

confidence: 87%

The structure of [Ir₂(CO)₂(μ-H)(μ-CO)(Ph₂PCH₂PPh₂)₂][BF₄] and comparisons with its rhodium analogue and other related doubly bridged A-frames

Sutherland¹,

Cowie²

1986

Can. J. Chem.

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“…It is worth noting that of nine possible cations all except 2b + and 3f + ( Figure S1) have closed C-C-C 3c-2e bonds, [37] and are thus nonclassical cations. [38] Consequently, we have attempted to access the C 1 -derivative of 2 by a different route: through the 1-substituted Cookson's diketone.…”

Section: Resultsmentioning

confidence: 99%

A Convenient Road to 1‐Chloropentacycloundecanes – A Joint Experimental and Computational Investigation

Sharapa¹,

Gayday²,

Mitlenko³

et al. 2011

Eur J Org Chem

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An efficient synthetic strategy to obtain 1‐chloro‐Cs‐trishomocubane and 1‐chloro‐D3‐trishomocubane is described. 1‐Chloro‐Cs‐trishomocubane is synthesized by a regioselective Diels–Alder reaction, and B3PW91/6‐31G(d,p) calculations offer a plausible explanation of the reaction mechanism. Surprisingly, 1‐chloro‐Cs‐trishomocubane does not undergo an acid‐catalyzed rearrangement to form 1‐chloro‐D3‐trishomocubane and was obtained by chlorosulfation of Cookson's diketone. A possible mechanism of the reaction involving the formation of Cs‐ and D3‐trishomocubane nonclassical cations was proposed on the basis of a mechanistic [B3PW91/6‐31G(d,p) and MP2/cc‐pVDZ] study.

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“…RESULTS Hydrogen Atoms on Ni(111). By using bond lengths fitting the pattern noted by Bau et al (9) for molecular clusters for atop, twofold and threefold positions ofhydrogen atoms on the model close-packed Ni(111) surface, the lowest energy was associated with the threefold bridging site (Table 3). Bridge site bonding was so effective that threefold sites were favored even where the hydrogen atom was moved at a constant height above the Ni plane.…”

mentioning

confidence: 86%

“…In the surface calculations, a constant metal-adatom bond distance for all sites always favors bridging sites for adatoms or molecules. (9,10). Bond distances listed in Table 2 were chosen to follow the experimentally observed pattern of increase in length on moving from atop a single metal atom to a bridging twofold site and further increase on moving to a triply bridging site or a threefold site.…”

mentioning

confidence: 99%

Metal-hydrogen bridge bonding of hydrocarbons on metal surfaces

Gavin

Reutt

Muetterties

1981

Proc. Natl. Acad. Sci. U.S.A.

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Molecular orbital studies implicate multicenter metal-hydrogen-carbon interactions as contributors to the bonding of chemisorbed hydrocarbons on clean metal surfaces. The most stable geometries appear to be those that achieve the maximum multicenter bonding to the coordinately unsaturated metal atoms in the vicinity of the anchoring metal-carbon interaction. Energy differences between possible surface sites are of the same magnitude as stabilization energies for three-center bonding of hydrogen atoms to the metal surface. Accordingly, secondary interactions of hydrogen with neighboring metal atoms may be significant determining factors in surface structures. The model predictions are compared with known structures and are used to propose a mechanism for hydrocarbon reactions on metal surfaces. These metal-hydrogen-carbon interactions are presumed to be intermediate points or states in C-H bond-breaking processes.A characterization of the bonding interaction between surfaces and adsorbed molecules is important to an understanding of surface chemistry. An analogy (1) between susfaces and molecular metal clusters has been proposed as one model framework within which representations for chemical interactions at surface interfaces can be developed. Fundamental to this approach is the assumption that local interactions, rather than bulk metal properties, are the major directors ofchemical reactions on surfaces. Obvious differences between molecular metal clusters and surfaces are conceded, but these differences also are presumed to influence the chemistry in a local fashion. This local model is amenable to theoretical analysis, and numerous attempts have been made to mimic the surface-adsorbate interaction by using semiempirical molecular orbital calculations (2-5). Because of the necessity to deal with finite numbers of orbitals in these methods, computations can be envisaged as theoretical models using a metal cluster for surface approximation. No model successfully predicts all properties of a surface that has chemisorbed species, but several models have had some success in qualitative predictions. In this paper, we describe a model based on the extended Huckel approach (6) in which trends in bond orders and energies are used to predict geometries of adsorbed species on metal surfaces. COMPUTATIONAL PROCEDURE Model surface computations were effected for a close-packed planar array of Ni atoms mimicking the (111) surface plane [for brevity, this pseudosurface will be referred to as Ni(111) throughout this article]. The metal-metal atom distance was taken to be 2.48 A, and the number of Ni atoms used to represent the surface was varied from 6 to 13. Due to the qualitative nature ofthe computations, the trends observed with the sevenatom clusters, close packed in a plane, could not be differentiated from the trends observed for larger clusters in two or more planes. The analysis was limited to the energy and bond order properties of the systems as a function of site and orientation. Bond distances and angles ...

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Structures of transition-metal hydride complexes

Cited by 212 publications

References 43 publications

The structure of [Ir₂(CO)₂(μ-H)(μ-CO)(Ph₂PCH₂PPh₂)₂][BF₄] and comparisons with its rhodium analogue and other related doubly bridged A-frames

The structure of [Ir₂(CO)₂(μ-H)(μ-CO)(Ph₂PCH₂PPh₂)₂][BF₄] and comparisons with its rhodium analogue and other related doubly bridged A-frames

A Convenient Road to 1‐Chloropentacycloundecanes – A Joint Experimental and Computational Investigation

Metal-hydrogen bridge bonding of hydrocarbons on metal surfaces

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Structures of transition-metal hydride complexes

Cited by 212 publications

References 43 publications

The structure of [Ir2(CO)2(μ-H)(μ-CO)(Ph2PCH2PPh2)2][BF4] and comparisons with its rhodium analogue and other related doubly bridged A-frames

The structure of [Ir2(CO)2(μ-H)(μ-CO)(Ph2PCH2PPh2)2][BF4] and comparisons with its rhodium analogue and other related doubly bridged A-frames

A Convenient Road to 1‐Chloropentacycloundecanes – A Joint Experimental and Computational Investigation

Metal-hydrogen bridge bonding of hydrocarbons on metal surfaces

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Product

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The structure of [Ir₂(CO)₂(μ-H)(μ-CO)(Ph₂PCH₂PPh₂)₂][BF₄] and comparisons with its rhodium analogue and other related doubly bridged A-frames

The structure of [Ir₂(CO)₂(μ-H)(μ-CO)(Ph₂PCH₂PPh₂)₂][BF₄] and comparisons with its rhodium analogue and other related doubly bridged A-frames