Impact of Lewis Base on Chemical Reactivity and Separation Efficiency for Hydrated Fourth-Row Transition Metal (II) Complexes: An ONIOM DFT/MM Study

2014 ◽  
Vol 118 (16) ◽  
pp. 2984-2994 ◽  
Author(s):  
Dingsheng He ◽  
Ming Ma
Keyword(s):  
Transition Metal ◽  
Separation Efficiency ◽  
Chemical Reactivity ◽  
Lewis Base

scholarly journals Frustration across the periodic table: heterolytic cleavage of dihydrogen by metal complexes

2017 ◽  
Vol 375 (2101) ◽  
pp. 20170002 ◽  
Author(s):  
R. Morris Bullock ◽  
Geoffrey M. Chambers
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Molecular Complexes ◽  
Main Group ◽  
Lewis Base ◽  
Metal Compounds ◽  
Metal Catalysis ◽  
Heterolytic Cleavage ◽  
Lewis Pairs

This perspective examines frustrated Lewis pairs (FLPs) in the context of heterolytic cleavage of H 2 by transition metal complexes, with an emphasis on molecular complexes bearing an intramolecular Lewis base. FLPs have traditionally been associated with main group compounds, yet many reactions of transition metal complexes support a broader classification of FLPs that includes certain types of transition metal complexes with reactivity resembling main group-based FLPs. This article surveys transition metal complexes that heterolytically cleave H 2 , which vary in the degree that the Lewis pairs within these systems interact. Many of the examples include complexes bearing a pendant amine functioning as the base with the metal functioning as the hydride acceptor. Consideration of transition metal compounds in the context of FLPs can inspire new innovations and improvements in transition metal catalysis. This article is part of the themed issue ‘Frustrated Lewis pair chemistry’.

Hydrogenation of Olefins, Alkynes, Allenes, and Arenes by Borane-based Frustrated Lewis Pairs

Synthesis ◽  
2021 ◽  
Author(s):  
Felix Wech ◽  
Urs Gellrich
Keyword(s):  
Transition Metal ◽  
Hydride Transfer ◽  
Lewis Base ◽  
Catalytic Reactions ◽  
Transfer Reactions ◽  
Organic Substrates ◽  
Frustrated Lewis Pairs ◽  
Hydrogen Activation ◽  
Hydrogenation Catalysts ◽  
Lewis Pairs

In recent years, borane-based frustrated Lewis pairs proved to be efficient hydrogenation catalysts and became an alternative to transition metal-based systems. The hydrogen activation by classic FLPs leads to a protonated Lewis base and a borohydride. Consequently, hydrogenations catalyzed by classic FLPs consist of stepwise hydride transfer reactions and protonations (or vice versa). More recently, systems that operate via an initial hydroboration have allowed extending the substrate scope for FLP catalyzed hydrogenations. Within this review, hydrogenations of organic substrates catalyzed by borane-based frustrated Lewis pairs are discussed. Emphasis is given to the mechanistic aspects of these catalytic reactions.

Quantum state control on the chemical reactivity of a transition metal vanadium cation in carbon dioxide activation

2019 ◽  
Vol 21 (13) ◽  
pp. 6868-6877 ◽  
Author(s):  
Yih Chung Chang ◽  
Yuntao Xu ◽  
Cheuk-Yiu Ng
Keyword(s):  
Carbon Dioxide ◽  
Transition Metal ◽  
Electronic State ◽  
Quantum State ◽  
Electron Spin ◽  
Chemical Reactivity ◽  
Ion Source ◽  
Atomic Transition ◽  
Spin Orbit ◽  
State Control

By utilizing a newly developed spin-orbit electronic state selected ion source for atomic transition metal vanadium cation (V+), the chemical reactivity of V+ with CO2 has been examined in detail, indicating that the titled reaction is dominantly governed by electron spin conservation, and thus the chemical reactivity can be controlled by quantum electronic state selections.

scholarly journals Asymmetric synthesis: From transition metals to organocatalysis

2008 ◽  
Vol 80 (5) ◽  
pp. 953-966 ◽  
Author(s):  
Pavel Kočovský ◽  
Andrei V. Malkov
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
Asymmetric Synthesis ◽  
Absolute Configuration ◽  
Nucleoside Analogs ◽  
Oxide Catalysts ◽  
Lewis Base ◽  
New Approach ◽  
Π Interactions ◽  
Metal Catalyzed

Umpolung in the allylation reaction is discussed with examples drawn from transition-metal-catalyzed allylic substitution (with the allylic unit acting as an electrophile) and Lewis base-catalyzed allylation of aldehydes with allyltrichlorosilane (with the allyl acting as a nucleophile). Iridium-catalyzed electrophilic allylation of O-nucleophiles has been employed in our new approach to C-nucleoside analogs, where the C-O bond (rather than C-C) was constructed stereospecifically. Variation of the absolute configuration in the starting segments allowed the synthesis of all four combinations of D/L-α/β-ribosides. In the nucleophilic allylation of aldehydes, chiral pyridine-type N-oxide catalysts are presented, in particular QUINOX and METHOX, and the intriguing behavior of QUINOX is discussed. Here, the π-π interactions between the substrate aldehyde and the catalyst are suggested to rationalize the experimental observations. Good correlation between the calculated energies for the transition states and the experimentally observed enantioselectivities has been obtained.

STM Investigations of Confined Transition Metal Chalcogenide Colloidal Particles

1996 ◽  
Vol 464 ◽  
Author(s):  
F. Kivuitu ◽  
S. P. Kelty
Keyword(s):  
Transition Metal ◽  
Colloidal Particles ◽  
Chemical Reactivity ◽  
Parent Material ◽  
Scanning Tunneling ◽  
Metal Chalcogenides ◽  
Tunneling Microscopy ◽  
Transition Metal Chalcogenides ◽  
Layered Transition Metal

ABSTRACTThe chemical reactivity of catalytic surfaces often arises from a unique crystal or electronic structure confined to the first few atomic layers. Scanning Tunneling Microscopy (STM) is particularly well suited to studying the spatially confined structural properties of such systems. In this paper, I report recent advances in the characterization of colloidal layered transition metal chalcogenides using STM. These particles mimic the surface (layer edge) properties of bulk catalytic materials. It is found that the materials adopt distinct equilibrium chemical and electronic structures as compared to the bulk. The possible significance of these novel structures in regard to the bulk catalytic functionality of the parent material will be briefly discussed.

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