Selectivities in Hydrocarbon Activation:  Kinetic and Thermodynamic Investigations of Reversible 1,2-RH-Elimination from (silox)2(tBu3SiNH)TiR (silox = tBu3SiO)

and, Jordan L. Bennett; Wolczanski, Peter T.

doi:10.1021/ja9707419

Cited by 247 publications

(221 citation statements)

References 121 publications

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“…Experimentally, a ratio R MC/HC ) 1.36 was found for bulky Ti compounds in a study by Wolczanski and co-workers. 43 Omission of the sp-hybridized (Ti-C 2 H) value leads to R MC/HC ) 1.29, in excellent agreement with the Wolczanski data. Table 6 and Figure 9 display the variations in R MC/HC ratios for all metals as obtained from calculated metal-hydrocarbon bond enthalpies.…”

Section: H N M-ch 3 Versus L N M-ch 3 Bond Enthalpies Insupporting

confidence: 70%

Computational Studies of Metal−Ligand Bond Enthalpies across the Transition Metal Series

et al. 2006

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Relative to the p-block of the periodic table, data for transition metal-ligand bond dissociation enthalpies are less comprehensive. Recent developments in computational methods make systematic assessment of trends in metal-ligand bond enthalpies across the transition series a relatively rapid and accurate exercise. We report a systematic study of metal-ligand bond enthalpies for saturated transition metal complexes that encompasses the entire d-block of the periodic table and a wide assortment of ligands. The saturated complexes have the form MH n -L such that closed-shell molecules are formed with the maximum number of two-center, two-electron (2c/2e) bonds under the constraint that the metal electron count does not exceed 12. Bond enthalpies for MH n -L molecules with higher electron counts (14 and 16 electrons) are assessed for some group 10 and 11 metals. The primary methods are density functional theory (DFT) using the hybrid B3LYP density functional and CCSD(T) ab initio computations. Bond enthalpies are reported as the first bond dissociation enthalpies for neutral and cationic complexes of the type MH n -R (R ) H, CH 3 , C 2 H 5 , CH(CH 3 ) 2 , C(CH 3 ) 3 , CH 2 F, C 2 H, C 2 H 3 , NH 2 , OH, F, and BH 2 ) for all transition elements. Electronic structure analysis of the complexes features natural bond orbital (NBO) analysis of bond polarity.

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Section: H N M-ch 3 Versus L N M-ch 3 Bond Enthalpies Insupporting

confidence: 70%

Computational Studies of Metal−Ligand Bond Enthalpies across the Transition Metal Series

et al. 2006

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“…Furthermore, the observation for all three ligands (PMe 3 , P(OMe) 3 , and CNneopentyl) of a vertical offset for substituted methyl derivatives of about 7 kcal/mol suggests this "additional" bond strength for these ligands might apply generally to other metal complexes. As seen with the data mentioned above by Wolczanski, the substituted methyl data points do indeed lie above the line joining hydrocarbons [22]. Data by Marks for Cp* 2 Th(R)Cl also show α-benzyl to be an outlier from the trend of six other hydrocarbons [23].…”

supporting

confidence: 73%

The Effects of Ancillary Ligands on Metal–Carbon Bond Strengths as Determined by C–H Activation

Jones

2015

Topics in Organometallic Chemistry

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The activation of C-H bonds by oxidative addition in about 30 different substrates has been examined with three closely related metal species, [Tp 0 RhL], where L ¼ CNneopentyl, PMe 3 , and P(OMe) 3 . Kinetic studies of the reductive elimination of R-H provided data to ascertain the relative metal-carbon bond strengths for a wide range of compounds. Trends in these bond strengths reveal that there are two classes of C-H substrates: parent hydrocarbons and substituted methanes. DFT calculations are used to support the observed trends, and some generalizations are made by comparison to other metal systems.

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“…The experimental work was reported by Wolczanski and co-worker. 71 We theoretically investigated this reaction with DFT, CCSD(T), and CASPT2 methods. 72 Though the MP2-MP4 methods provided considerably different energy changes from other methods, the DFT, CCSD(T), and CASPT2 presented similar energy changes.…”

Section: ¹1mentioning

confidence: 99%

Theoretical and Computational Study of a Complex System Consisting of Transition Metal Element(s): How to Understand and Predict Its Geometry, Bonding Nature, Molecular Property, and Reaction Behavior

Sakaki

2015

Bulletin of the Chemical Society of Japan

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Complex chemical systems consisting of transition metal element(s) are important and attractive research targets in both experimental chemistry and theoretical chemistry. Transition-metal complexes with carbon dioxide are discussed as one example, in which the coordination geometry, bonding nature, and reactivity are understood well and predicted with the HOMO and the number of d electrons. The spin-multiplicity of inverse sandwich-type dinuclear transition-metal complexes, which have been synthesized recently as a new type of compound, is discussed as another example based on CASPT2 calculations, in which the clear relationship between the spin multiplicity of its ground state and the number of d electrons is presented. Theoretical understanding of various organometallic reactions has been an important endeavor over the last two decades. Insertion reactions of olefin and carbon dioxide into MH and Malkyl bonds and σ-bond activation reactions are discussed with orbital interaction diagrams based on perturbation theory. In particular, detailed discussion of the characteristic features of a new type of oxidative addition to an ML moiety (L = neutral ligand such as alkene and alkyne) and heterolytic σ-bond activation by an MX moiety (X = anionic ligand). It is still a central challenge to elucidate the reaction mechanisms of catalytic reactions by transition metal complexes. The reaction mechanisms and electronic processes of Ru-catalyzed hydrogenation of carbon dioxide, Pt-, Rh-, and Zr-catalyzed hydrosilylations of alkene, Ir-catalyzed borylation of benzene, and the Hiyama cross-coupling reaction are analyzed based on computational results. We wish to present how to understand the mechanism based on the number of d electrons and the energy of d orbitals in discussion. Also, the importance of solvation and crystalline effects in the theoretical study of transition-metal complexes is discussed based on our recent theoretical studies of mixed-valence complex and a single crystal of a Pt(II) complex.

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Selectivities in Hydrocarbon Activation: Kinetic and Thermodynamic Investigations of Reversible 1,2-RH-Elimination from (silox)₂(^tBu₃SiNH)TiR (silox = ^tBu₃SiO)

Cited by 247 publications

References 121 publications

Computational Studies of Metal−Ligand Bond Enthalpies across the Transition Metal Series

Computational Studies of Metal−Ligand Bond Enthalpies across the Transition Metal Series

The Effects of Ancillary Ligands on Metal–Carbon Bond Strengths as Determined by C–H Activation

Theoretical and Computational Study of a Complex System Consisting of Transition Metal Element(s): How to Understand and Predict Its Geometry, Bonding Nature, Molecular Property, and Reaction Behavior

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