Related Experiment Video
Updated: Feb 17, 2026

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry
Published on: October 18, 2019
Silyl-Hydrosilane Exchange at a Magnesium Triphenylsilyl Complex Supported by a Cyclen-Derived NNNN-Type Macrocyclic
Lara E Lemmerz1, Valeri Leich1, Daniel Martin1
1Institute of Inorganic Chemistry, RWTH Aachen University , Landoltweg 1, 52056 Aachen, Germany.
Abstract:
The magnesium triphenylsilyl complex [(Me3TACD)Mg(SiPh3)] (2) was synthesized from magnesium bis(triphenylsilyl) [Mg(SiPh3)2(THF)2]·THF (1; THF = tetrahydrofuran) and the NNNN-type macrocyclic amidotriamine proligand (Me3TACD)H ((Me3TACD)H = Me3[12]aneN4 = 1,4,7-trimethyl-1,4,7,10-tetraazacyclododecane). Treating 2 with AlR3 (R = Me, Et) gave the magnesium triphenylsilyl complexes with "blocked" amido function [(Me3TACD·AlR3)Mg(SiPh3)] (3a: R = Me; 3b: R = Et). Instead of forming a Mg-H bond upon reaction with dihydrogen or hydrosilanes, 2 and 3a,b underwent rapid silyl-silane exchange with hydrosilanes. Treating the ethyl complex [(Me3TACD·AlEt3)MgEt] with H3SiPh gave [(Me3TACD·AlEt3)MgH] (4), albeit not in a reproducible manner. The silyl-hydrosilane exchange allows access to other magnesium silyls of the type [(Me3TACD)Mg(SiR'3)] (5a: SiR'3 = SiH2Ph; 5b: SiR'3 = SiHPh2) and [(Me3TACD·AlR3)Mg(SiR'3)] (6a: SiR'3 = SiH2Ph, R = Me; 6b: SiR'3 = SiH2Ph, R = Et; 7a: SiR'3 = SiHPh2, R = Me; 7b: SiR'3 = SiHPh2, R = Et). The reaction of 2 with H2SiMePh in THF at room temperature resulted in an equilibrium (Keq ≈ 1). Protonolysis of 2 with Brønsted acids (HX) 2,5-di-tert-butylphenol, phenylacetylene, acetophenone, aniline, and triethylammonium chloride each gave a compound [(Me3TACD)Mg(X)] with the conjugated base coordinated at the magnesium along with HSiPh3. The magnesium silyls 1, 2, and 7b as well as the magnesium hydride 4 contain a distorted square-pyramidal magnesium center according to single-crystal X-ray diffraction.
More Related Videos
04:51Author Spotlight: Functionalizing Metal-Organic Frameworks: Advancements, Challenges, and the Power of Post-Synthetic Ligand Exchange
Published on: June 23, 2023
09:45Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene
Published on: March 20, 2017
Related Concept Videos
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Aromatic Hydrocarbon Cations: Structural Overview
Removing one hydrogen from the intervening CH2 group...
Cycloaddition Reactions: MO Requirements for Thermal Activation
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction
Cycloaddition Reactions: Overview