PCy3

Tri-cyclohexylphosphine, abbreviated PCy3, is a bulky monodentate phosphine ligand used in homogeneous organometallic catalysis. Its chemical formula is P(C6H11)3, where Cy denotes cyclohexyl groups. PCy3 is valued for its combination of strong σ-donor ability and large steric bulk, which can stabilize low-coordinate metal centers and influence catalytic selectivity.

In terms of properties, PCy3 is typically handled under inert atmosphere due to the air-sensitivity of many trialkylphosphines. It is commonly obtained as a colorless to pale yellow liquid or viscous solid. As a ligand, it binds through the phosphorus lone pair to transition metals, forming complexes that are active in a range of catalytic processes. The bulky cyclohexyl substituents reduce tendency toward unwanted aggregation and can steer reactions toward productive pathways by modulating substrate access to the metal center.

Applications of PCy3 span numerous areas of homogeneous catalysis. It is frequently employed in palladium- and rhodium-catalyzed reactions, including cross-coupling, hydroformylation, and hydrogenation, where its electron-rich and sterically demanding character can enhance turnover and alter selectivity. PCy3 is often used in ligand screening and in the design of catalysts for challenging transformations that benefit from a robust, bulky phosphine environment.

PCy3 is widely available from chemical suppliers and is used alongside other bulky phosphines and standard ligands in both academic and industrial catalytic research. Safety data reflect typical handling requirements for air-sensitive phosphines.