Theoretical Study of the Relativistic Effects on the Bonds between HfCl3 and H and between ThCl3 and H

Wezenbeek, Egbert van; Baerends, Evert Jan; Ziegler, Tom

doi:10.1021/ic00105a039

Cited by 10 publications

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“…heavy atoms in (1) dissociation energies, [18][19][20][21][22] (2) bond lengths and bond strengths, 21,23,24 (3) dipole moments, 20,21 (4) nuclear magnetic resonance (NMR) shieldings [25][26][27][28][29] and (5) electric field gradients (EFG). 22,[30][31][32][33] For example, in a Dirac-Hartree-Fock (DHF) study of the uranyl ion, 30 the inclusion of relativistic effects leads to a bond length expansion, and the presence of the ''U(6p) core-hole'', the depletion of charge out of the 6p s orbital because of the overlap of O(2p) with the high lying antibonding U(6p s ) + O(2s) orbital exerts a large influence on the size of the EFG.…”

Section: Treatment Of Relativistic Effectsmentioning

confidence: 99%

Recent advances in computational actinoid chemistry

2012

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We briefly review advances in computational actinoid (An) chemistry during the past ten years in regard to two issues: the geometrical and electronic structures, and reactions. The former addresses the An-O, An-C, and M-An (M is a metal atom including An) bonds in the actinoid molecular systems, including actinoid oxo and oxide species, actinoid-carbenoid, dinuclear and diatomic systems, and the latter the hydration and ligand exchange, the disproportionation, the oxidation, the reduction of uranyl, hydroamination, and the photolysis of uranium azide. Concerning their relevance to the electronic structures and reactions of actinoids and their importance in the development of an advanced nuclear fuel cycle, we also mentioned the work on actinoid carbides and nitrides, which have been proposed to be candidates of the next generation of nuclear fuel, and the oxidation of PuO(x), which is important to understand the speciation of actinoids in the environment, followed by a brief discussion on the urgent need for a heavier involvement of computational actinoid chemistry in developing advanced reprocessing protocols of spent nuclear fuel. The paper is concluded with an outlook.

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Section: Treatment Of Relativistic Effectsmentioning

confidence: 99%

Recent advances in computational actinoid chemistry

2012

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“…The origin of the relativistic bond contraction and stabilization can ultimately be traced back to the mass increase of valence electrons (mostly in s orbitals) moving near the nuclei. This mass increase will reduce the kinetic energy, which in turn allows the bonds to contract and stabilize. − The relativistic bond contraction and stabilization are especially important for compounds containing gold and mercury. ,29a However, it is also noticeable for actinides . Relativistic bond expansions are comparatively uncommon and might come along with a bond stabilization (e.g., PbO) or destabilization (e.g., AuF and AuCl).…”

Section: 3 Importance Of Relativistic Corrections For Structures and ...mentioning

confidence: 99%

Theoretical Methods of Potential Use for Studies of Inorganic Reaction Mechanisms

2005

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“…The third-row transition-metal complexes undergo oxidative-addition reactions, M I + A−B → M III (A)(B), more easily than their second-row transition-metal congeners because late third-row transition metals have either d n s 1 ground states or d n s 1 low-lying excited states, while late second-row transition metals have d n +1 ground states with high-lying d n s 1 excited states. , This view emphasizes the importance of forming sd hybrids for the two new covalent bonds in the product. The origin of the atomic differences has been attributed to relativistic effects, which stabilize the ( n + 1)s orbitals and destabilize the n d orbitals more for the heavier third-row transition metals. On the other hand, since the redox ability of transition metals is reflected by their ionization potential (IP), the energy gap between the metal and ligand is directly proportional to the IP of the transition metal.…”

Section: Discussionmentioning

confidence: 99%

Theoretical Studies of Inorganic and Organometallic Reaction Mechanisms. 14. β-Hydrogen Transfer and Alkene/Alkyne Insertion at a Cationic Iridium Center

et al. 1998

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Recent experimental work shows that alkanes can be activated by Cp*Ir(PMe 3 )(CH 3 ) + at room temperature to generate olefin complexes. The reaction begins with alkane activation by oxidative addition (OA) followed by reductive elimination (RE) of methane and then olefin formation by the -H transfer from the bound alkyl. Ab initio calculations and density functional theory (DFT) studies of ethane activation by CpIr(PH 3 )(CH 3 ) + (1) to generate CpIr-(PH 3 )(η 2 -C 2 H 4 )(H) + (7) show that the -H transfer from CpIr(PH 3 )(C 2 H 5 ) + (5) to 7 is exothermic by 12 and 16 kcal/mol with a very low barrier of 0.7 and 0.4 kcal/mol at the DFT and CCSD levels, respectively. Thus, the rate-determining step in alkane dehydrogenation to olefin complexes by Cp*Ir(PMe 3 )(CH 3 ) + is the alkane OA step. These results are in very good agreement with the experimental work of Bergman and co-workers. A strong stabilizing interaction between either ethylene or acetylene and CpIr(PH 3 )(CH 3 ) + leads to high activation barriers (25-36 kcal/mol) for the insertion processes of ethylene or acetylene. In comparison to ethylene, the insertion reaction of acetylene with the CpIr(PH 3 )(CH 3 ) + complex is more favorable. Thus, the dimerization of terminal alkynes catalyzed by cationic iridium complexes is plausible.

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Theoretical Study of the Relativistic Effects on the Bonds between HfCl3 and H and between ThCl3 and H

Cited by 10 publications

References 0 publications

Recent advances in computational actinoid chemistry

Recent advances in computational actinoid chemistry

Theoretical Methods of Potential Use for Studies of Inorganic Reaction Mechanisms

Theoretical Studies of Inorganic and Organometallic Reaction Mechanisms. 14. β-Hydrogen Transfer and Alkene/Alkyne Insertion at a Cationic Iridium Center

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