Highly active, chemo- and enantioselective Pt-SPO catalytic systems for the synthesis of aromatic carboxamides

2015 ◽  
Vol 5 (7) ◽  
pp. 3822-3828 ◽  
Author(s):  
Henrik Gulyás ◽  
Ivan Rivilla ◽  
Simona Curreli ◽  
Zoraida Freixa ◽  
Piet W. N. M. van Leeuwen
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Kinetic Resolution ◽  
Platinum Complexes ◽  
Catalytic Systems ◽  
Highly Active

Platinum complexes of the chiral non-racemizing SPO ligand 1 have been discovered to be the first artificial transition metal complexes providing kinetic resolution in the hydration of a racemic chiral nitrile.

scholarly journals Recent Advances in Catalysis Involving Bidentate N-Heterocyclic Carbene Ligands

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 95
Author(s):  
Abdollah Neshat ◽  
Piero Mastrorilli ◽  
Ali Mousavizadeh Mobarakeh
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Metal Ion ◽  
Co2 Reduction ◽  
Transition Metal Ions ◽  
Transfer Hydrogenation ◽  
Coupling Reactions ◽  
Catalytic Systems ◽  
Almost All

Since the discovery of persistent carbenes by the isolation of 1,3-di-l-adamantylimidazol-2-ylidene by Arduengo and coworkers, we witnessed a fast growth in the design and applications of this class of ligands and their metal complexes. Modular synthesis and ease of electronic and steric adjustability made this class of sigma donors highly popular among chemists. While the nature of the metal-carbon bond in transition metal complexes bearing N-heterocyclic carbenes (NHCs) is predominantly considered to be neutral sigma or dative bonds, the strength of the bond is highly dependent on the energy match between the highest occupied molecular orbital (HOMO) of the NHC ligand and that of the metal ion. Because of their versatility, the coordination chemistry of NHC ligands with was explored with almost all transition metal ions. Other than the transition metals, NHCs are also capable of establishing a chemical bond with the main group elements. The advances in the catalytic applications of the NHC ligands linked with a second tether are discussed. For clarity, more frequently targeted catalytic reactions are considered first. Carbon–carbon coupling reactions, transfer hydrogenation of alkenes and carbonyl compounds, ketone hydrosilylation, and chiral catalysis are among highly popular reactions. Areas where the efficacy of the NHC based catalytic systems were explored to a lesser extent include CO2 reduction, C-H borylation, alkyl amination, and hydroamination reactions. Furthermore, the synthesis and applications of transition metal complexes are covered.

Physical techniques and catalyst preparation: Determining the interactions of transition-metal complexes with oxide surfaces

2006 ◽  
Vol 78 (5) ◽  
pp. 1039-1055 ◽  
Author(s):  
Xavier Carrier ◽  
Eric Marceau ◽  
Michel Che
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Catalyst Preparation ◽  
Molecular Approach ◽  
Catalytic Systems ◽  
Oxide Supports ◽  
X Ray ◽  
Oxide Support ◽  
X Ray Absorption

This contribution presents the molecular approach used to investigate the different preparation steps of important catalytic systems, based on Mo, Ni, and Co. The first preparation step consists of impregnating oxide supports by aqueous solutions of transition-metal complexes (TMCs), called precursor complexes, and involves the liquid-solid (wet) interface. The following steps consist of thermal activation treatments, involving the gas-solid (dry) interface. The molecular approach is based on (i) the use of the TMC to monitor and probe the nature of its own interactions with the oxide support, (ii) the selection of the most appropriate techniques to monitor such interactions, and (iii) the design of experiments to identify and isolate the key parameters controlling the "TMC-oxide support" interactions.Physical techniques play a key role in the characterization of catalyst preparation both at the macroscopic [temperature-programmed reduction (TPR), X-ray diffraction (XRD)] and molecular [Raman, X-ray absorption near-edge spectroscopy-extended X-ray absorption fine structure (XANES)-EXAFS, diffuse reflectance UV-vis] levels, particularly when they are used simultaneously. They give some insight into the structure of the species existing on the surface, with the oxide support behaving as a solid ligand, when exposed for a short time to the precursor complex solution or after thermal treatment, or, for longer contact times, as a reactant.

Mechanochemical changes on cyclometalated Ir(iii) acyclic carbene complexes – design and tuning of luminescent mechanochromic transition metal complexes

2020 ◽  
Vol 7 (3) ◽  
pp. 786-794 ◽  
Author(s):  
Jingqi Han ◽  
Kin-Man Tang ◽  
Shun-Cheung Cheng ◽  
Chi-On Ng ◽  
Yuen-Kiu Chun ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Carbene Complexes ◽  
New Class

A new class of luminescent cyclometalated Ir(iii) complexes with readily tunable mechanochromic properties derived from the mechanically induced trans-to-cis isomerization have been developed.

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