Transition metal complexes with functionalized indenyl phosphine ligands: structures and catalytic properties

Area of Science:

• Organometallic Chemistry
• Catalysis

Background:

• Transition-metal indenyl complexes display unique reactivity compared to cyclopentadienyl analogues.
• The "indenyl effect" enhances reactivity in substitution and related reactions.
• Over 10 metal-indenyl bonding modes have been documented.

Purpose of the Study:

• To review the impact and applications of indenyl phosphines in organometallic chemistry and transition-metal catalysis over the past two decades.
• To highlight novel cationic and zwitterionic metal complexes with P,N-substituted indene/indenide ligands.
• To discuss the catalytic activity of these complexes in E-H bond cleavage and addition reactions.

Main Methods:

• Review of literature on indenyl phosphine chemistry and catalysis.
• Description of metal complexes featuring P,N-substituted indene or indenide ligands.
• Analysis of catalytic applications in E-H bond activation and cross-coupling reactions.

Main Results:

• Indenyl phosphines are versatile ligands, particularly for palladium-catalyzed C-C and C-N cross-coupling reactions (ligands L3-L11).
• Cationic and zwitterionic complexes with P,N-substituted ligands facilitate E-H (E = H, Si, B) bond cleavage and catalyze E-H additions.
• Optically active indenyl phosphine ligands provide stereoselective control in rhodium-catalyzed oxidative addition reactions.

Conclusions:

• Indenyl phosphines are crucial in modern organometallic chemistry and catalysis.
• These ligands enable diverse catalytic transformations, including cross-coupling and E-H bond functionalization.
• The development of chiral indenyl phosphines offers advanced stereocontrol in metal-centered reactions.