Donor-stabilised molecular Mg/Al-bimetallic hydrides

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry
• Catalysis

Background:

• Bimetallic compounds containing magnesium and aluminum are of interest due to their unique bonding and reactivity.
• Understanding the synthesis and properties of these complexes can lead to new catalytic applications.

Purpose of the Study:

• To synthesize and characterize novel bimetallic magnesium-aluminum addition compounds.
• To investigate the reactivity of these compounds, particularly their potential as catalysts.

Main Methods:

• Reaction of dimethylmagnesium with dimethylaluminum hydride in various ethereal solvents.
• Salt metathesis reactions with potassium 1,2,3,4,5-pentamethyl-cyclopentadienide.
• Spectroscopic characterization (NMR, X-ray crystallography) of the synthesized compounds.
• Evaluation of catalytic activity in reduction and hydromagnesiation reactions.

Main Results:

• Formation of bimetallic monomagnesium addition compounds [(do)xMg{(μ2-H)(AlMe3)}2] in common ethereal solvents.
• Synthesis of an 8-membered ring structure in methyl tert-butyl ether due to alkyl/hydrido overexchange.
• Isolation of a rare magnesium half-sandwich hydride complex [Cp*Mg{(μ2-H)(AlMe3)}(thf)2].
• Demonstration of selective pyridine reduction to 1,4-dihydropyridide and hydromagnesiation of 1-hexene without transition metal catalysts.

Conclusions:

• Novel bimetallic magnesium-aluminum hydride complexes can be synthesized with tunable structures.
• These complexes exhibit inherent reactivity, enabling selective organic transformations.
• The findings open avenues for developing new homogeneous catalysts based on main group elements.