Comparison of metal-hydrogen, -oxygen, -nitrogen and -carbon bond strengths and evaluation of functional group additivity principles for organoruthenium and organoplatinum compounds

Bryndza, Henry E.; Domaille, Peter J.; Tam, William; Fong, Lawrence K.; Paciello, Rocco; Bercaw, John E.

doi:10.1016/s0277-5387(00)81773-8

Cited by 69 publications

(63 citation statements)

References 55 publications

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“…Thus, the relative rates of C-H bond activation by systems that initiate oxidative addition are potentially controlled to a significant degree by the metal-carbon bond strengths of the incipient products, and the commonly observed selectivity of oxidative addition reactions of pyrrole could be dictated by the combination of weak N-H (relative to C-H BDEs) and relatively strong M-N pyrrolyl bonds (although M-N pyrrolyl bonds may be weaker than M-C pyrrolyl bonds, the difference in BDE may not make up for the approximately 20 kcal/ mol difference in N-H versus C-H BDEs of pyrrole). [60][61][62] Given these considerations, computational studies were performed to assist our efforts to propose the most reasonable pathway for the formation of 2 from complex 1 and pyrrole.…”

Section: Resultsmentioning

confidence: 99%

Ruthenium(II)-Mediated Carbon−Carbon Bond Formation between Acetonitrile and Pyrrole: Combined Experimental and Computational Study

et al. 2005

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The reaction of TpRu(CO)(NCMe)(Me) (1) and pyrrole forms TpRu(CO){κ2-N,N-(H)NC(Me)(NC4H3)} (2). The formation of complex 2 involves the cleavage of the N−H bond and 2-position C−H bonds of pyrrole as well as a C−C bond forming step between pyrrole and the acetonitrile ligand of 1. Mechanistic studies indicate that the most likely reaction pathway involves initial metal-mediated N−H activation of pyrrole to produce TpRu(CO)(N-pyrrolyl)(NCMe) (3) followed by C−C bond formation and proton transfer. Complex 3 has been independently prepared and demonstrated to convert to 2. Computational studies support the suggested selectivity for initial N−H bond cleavage in preference to C−H bond activation.

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Section: Resultsmentioning

confidence: 99%

Ruthenium(II)-Mediated Carbon−Carbon Bond Formation between Acetonitrile and Pyrrole: Combined Experimental and Computational Study

et al. 2005

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“…It has often been asserted that late metal-oxygen and -nitrogen bonds are weaker than their early-metal counterparts, but if we focus on specific homolytic bond dissociation energies (BDEs), rather than average bond energies, only a few studies have been carried out to test this expectation. 29,30 More systematic information is available about relative (rather than absolute) bond energies. In a widely cited study by Bryndza, Bercaw, and co-workers, a correlation was proposed between the relative bond strengths of metal-heteroatom bonds (M-X) and their corresponding acids (H-X).…”

Section: Direct Studies Of the Primary Reactions Of Metal Alkoxides Amentioning

confidence: 99%

“…In a widely cited study by Bryndza, Bercaw, and co-workers, a correlation was proposed between the relative bond strengths of metal-heteroatom bonds (M-X) and their corresponding acids (H-X). 30 In these systems, a case was made that a strong H-X bond correlates to a strong M-X bond, and a weak H-X bond correlates to a weak M-X bond (X = OR, NR 2 , CR 3 ). More specifically, the difference in the BDEs between the [Pt]-OMe and H-OMe bonds is approximately the same as the difference in the BDEs between [Pt]-NMePh and H-NMePh bonds (eq 6).…”

Section: Direct Studies Of the Primary Reactions Of Metal Alkoxides Amentioning

confidence: 99%

Formation, Reactivity, and Properties of Nondative Late Transition Metal−Oxygen and −Nitrogen Bonds

et al. 2001

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Complexes containing bonds between heteroatoms such as nitrogen and oxygen and "late" transition metals (i.e., those located on the right side of the transition series) have been implicated as reactive intermediates in numerous important catalytic systems. Despite this, our understanding of such M-X linkages still lags behind that of their M-H and M-C analogues. New synthetic strategies have now made possible the isolation and study of a variety of monomeric late-metal alkoxide, aryloxide, and amide complexes, including parent hydroxide and amide species. The heteroatoms in these materials form surprisingly strong bonds to their metal centers, and their bond energies do not necessarily correlate with the energies of the corresponding H-X bonds. The M-X complexes typically exhibit nucleophilic reactivity, in some cases form strong hydrogen bonds to proton donors, and even deprotonate relatively weak acids. These observations, as well as thermodynamic investigations, suggest that late metal-heteroatom bonds are strongly polarized and possess significant ionic character, properties that play an important role in their interactions with organic compounds.

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“…By correlating our recent calorimetry measurements of the adiabatic bond dissociation enthalpies of three oxygen‐bound molecular fragments (–OD, –OCH 3 , and –O(O)CH) to the Pt(111) surface, it was found that these RO–Pt(111) bond enthalpies vary linearly with the RO–H bond enthalpies in the corresponding gas‐phase molecules (water, methanol and formic acid), with a slope of unity, as shown in Figure . Such a correlation had previously been shown for ligand binding to organometallic complexes, where the sigma bond energies of many ligands to metal centers have been determined from equilibrium measurements. The results discussed here confirmed for the first time that such a relationship holds for binding molecular fragments to an extended surface of a late transition metal, Pt(111).…”

Section: Calorimetric Energies Of Adsorbed Catalytic Intermediates Onmentioning

confidence: 62%

Single‐Crystal Adsorption Calorimetry on Well‐Defined Surfaces: From Single Crystals to Supported Nanoparticles

Schauermann

Silbaugh

Campbell

2014

The Chemical Record

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Single-crystal adsorption calorimetry (SCAC) measures the energetics of gas-surface interactions in a direct way and can be applied to a broad range of well-defined model surfaces. In this Personal Account we review some of the recent advances in understanding the interaction of gaseous molecules with single-crystal surfaces and well-defined supported metallic nanoparticles by this powerful technique. SCAC was applied on single-crystal surfaces to determine formation enthalpies of adsorbed molecular fragments typically formed during heterogeneously catalyzed reactions involving hydrocarbons. On supported metal nanoparticles, the binding energies of gaseous species were determined by SCAC as a function of the particle size. The reported data provide valuable information for ongoing research in many fields of heterogeneous catalysis and materials science. In addition, direct calorimetric measurements serve as benchmarks for the improvement of computational approaches to understanding surface chemistry.

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Comparison of metal-hydrogen, -oxygen, -nitrogen and -carbon bond strengths and evaluation of functional group additivity principles for organoruthenium and organoplatinum compounds

Cited by 69 publications

References 55 publications

Ruthenium(II)-Mediated Carbon−Carbon Bond Formation between Acetonitrile and Pyrrole: Combined Experimental and Computational Study

Ruthenium(II)-Mediated Carbon−Carbon Bond Formation between Acetonitrile and Pyrrole: Combined Experimental and Computational Study

Formation, Reactivity, and Properties of Nondative Late Transition Metal−Oxygen and −Nitrogen Bonds

Single‐Crystal Adsorption Calorimetry on Well‐Defined Surfaces: From Single Crystals to Supported Nanoparticles

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