Phosphinidene Transfer by an N-Heterocyclic Carbene-Parent Phosphinidene Complex

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry
• Reaction Mechanisms

Background:

• N-heterocyclic carbene (NHC)-phosphinidene complexes are emerging reagents in phosphorus chemistry.
• Phosphinidene transfer reactions are crucial for synthesizing novel phosphorus-containing compounds but remain challenging.
• Developing efficient phosphinidene transfer protocols is essential for advancing synthetic phosphorus chemistry.

Purpose of the Study:

• To investigate the utility of an NHC-phosphinidene complex for phosphinidene transfer reactions.
• To explore the scope of phosphinidene transfer to different substrates, including quinones and silylenes.
• To elucidate the mechanism of phosphinidene transfer from NHC-phosphinidene complexes.

Main Methods:

• Synthesis and characterization of the (1,3-bis(isopropyl)imidazol-2-ylidene)-parent phosphinidene complex.
• Experimental investigation of phosphinidene transfer reactions with 9,10-phenanthrenequinone and an amidinato silylsilylene complex.
• Computational studies (theoretical calculations) to determine the reaction mechanism.

Main Results:

• The NHC-phosphinidene complex successfully transferred the parent phosphinidene to 9,10-phenanthrenequinone, yielding imidazolium tris(phenanthrene-9,10-dioxy)phosphate.
• The complex also transferred the parent phosphinidene to the amidinato silylsilylene complex, forming an amidinato phosphasilene.
• Theoretical studies indicated that the phosphinidene transfer from the NHC to the silylsilylene follows an S_N2-type mechanism.

Conclusions:

• NHC-phosphinidene complexes are effective reagents for phosphinidene transfer reactions.
• The developed method allows for the synthesis of novel phosphorus compounds like phosphasilenes.
• The S_N2-type mechanism provides insight into the reactivity and scope of these phosphinidene transfer reactions.