Related Experiment Video
Updated: Apr 25, 2026

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry
Published on: October 18, 2019
Trisphosphine-chelate-substituted molybdenum and tungsten nitrosyl hydrides as highly active catalysts for olefin
Subrata Chakraborty1, Olivier Blacque, Thomas Fox
1Department of Chemistry, University of Zürich, Winterthurerstrasse 190, 8057 Zürich (Switzerland).
Abstract:
Reaction of [M(NO)Cl3 (NCMe)2 ] (M=Mo, W) with (iPr2 PCH2 CH2 )2 PPh (etp(i) p) at room temperature afforded the syn/anti-[M(NO)Cl3 (mer-etp(i) p)] complexes (M=Mo, a; W, b; 3 a,b(syn,anti); syn and anti refer to the relative position of Ph(etp(i) p) and NO). Reduction of 3 a,b(syn,anti) produced [M(NO)Cl2 (mer-etp(i) p)] (4 a,b(syn)), [M(NO)Cl(NCMe)(mer-etp(i) p)] (5 a,b(syn,anti)), and [M(NO)Cl(η(2) -ethylene)(mer-etp(i) p)] (6 a,b(syn,anti)) complexes. The hydrides [M(NO)H(η(2) -ethylene)(mer-etp(i) p)] (7 a,b(syn,anti)) were obtained from 6 a,b(syn,anti) using NaHBEt3 (75 °C, THF) or LiBH4 (80 °C, Et3 N), respectively. 7 a,b(syn,anti) were probed in olefin hydrogenations in the absence or presence of a hydrosilane/B(C6 F5 )3 mixture. The 7 a,b(syn,anti)/Et3 SiH/B(C6 F5 )3 co-catalytic systems were highly active in various olefin hydrogenations (60 bar H2 , 140 °C), with maximum TOFs of 5250 h(-1) (7 a(syn,anti)) and 8200 h(-1) (7 b(syn,anti)) for 1-hexene hydrogenation. The Et3 SiH/(B(C6 F5 )3 co-catalyst is anticipated to generate a [Et3 Si](+) cation attaching to the ONO atom. This facilitates NO bending and accelerates catalysis by providing a vacant site. Inverse DKIE effects were observed for the 7 a(syn,anti)/Et3 SiH/(B(C6 F5 )3 (kH /kD =0.55) and the 7 b(syn,anti)/Et3 SiH/(B(C6 F5 )3 (kH /kD =0.65) co-catalytic mixtures (20 bar H2 /D2 , 140 °C).
More Related Videos
10:51The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes
Published on: April 10, 2015
10:52Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
Published on: July 27, 2022
Related Concept Videos
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation...
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Reduction of Alkenes: Catalytic Hydrogenation
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
Heterogeneous Catalysis
Olefin Metathesis Polymerization: Overview
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...