Selective dimerization of Lewis-acid/base-stabilized phosphanylalanes.

Area of Science:

• Organometallic chemistry
• Coordination chemistry
• Heterocyclic chemistry

Background:

• Tungsten carbonyl phosphine complexes are versatile precursors in organometallic synthesis.
• Aluminum hydride complexes are widely used as reducing agents and in the synthesis of aluminum-containing compounds.

Purpose of the Study:

• To synthesize novel four-membered heterocyclic compounds involving tungsten, phosphorus, and aluminum.
• To investigate the isomeric equilibria and stability of these newly formed compounds.
• To explore the reactivity and potential hydrogen elimination pathways using theoretical methods.

Main Methods:

• Synthesis of tungsten carbonyl phosphine compounds.
• Reaction with aluminum hydride complexes (H(3)Al⋅NR(3)).
• Characterization using Nuclear Magnetic Resonance (NMR) spectroscopy.
• Density Functional Theory (DFT) calculations for stability and reactivity analysis.

Main Results:

• Formation of two distinct four-membered heterocyclic compounds: [({(CO)(5)W}P(H)AlH⋅NEt(3))(2)] and [({(CO)(5)W}PhPAlH⋅NMe(3))(2)].
• Observation of fast equilibria between isomers in solution via NMR spectroscopy.
• DFT calculations indicate potential reversibility of hydrogen elimination in one of the synthesized compounds.

Conclusions:

• The reaction provides a route to novel tungsten-containing four-membered heterocycles.
• Isomeric equilibria are a key feature of these compounds in solution.
• Theoretical studies offer insights into the stability and reaction mechanisms, particularly hydrogen elimination.