Monodentate Phosphine Ligands

A monodentate phosphine ligand refers to a ligand having only one coordinating atom, and this coordinating atom is a P atom. Compared with other ligands, monophosphine ligands are easy to synthesize, flexible in structure, and excellent in catalytic performance. Therefore, the application value of monodentate phosphine ligands is very large. In addition, monodentate phosphine ligands are abundant in variety and have a wide range of applications, so they have a pivotal position in many fields.

Applications

Monodentate phosphine ligands are applied in organic synthesis, analytical chemistry, and pharmaceutical industries due to their good structural properties, diversity, and high economics.

• Organic chemistry: In the field of organic synthesis, when a central metal ion can only provide one coordination orbital, the monophosphine ligand can complex with a ligand-centered metal ion to catalyze the reaction. In addition, monophosphine ligands are more susceptible to chiral modification and control of chiral sites, resulting in chiral products with unique enantioselectivity. Because of these advantages, the monodentate phosphine ligand can form a metal catalyst with a metal atom (e.g., palladium, ruthenium, etc.) to function in the field of asymmetric catalysis in organic synthesis. At present, monophosphine ligands have been successfully applied to asymmetric catalytic conjugate addition reactions, asymmetric catalytic allyl substitution reactions, asymmetric catalytic hydrogenation reactions, and the like.
• Material chemistry: Some monodentate phosphine ligands (such as dpnp) have strong fluorescence and can be used as high-efficiency phosphorescent materials, and can also be made into luminescent paint for organic light-emitting diodes. They can also be mixed with plastic to make various display materials.
• Analytical chemistry: Some monodentate phosphine ligands, such as triphenylphosphine, can be used as analytical reagents. In analytical chemistry, monodentate phosphine ligands can be used as standard samples for the determination of phosphorus in organic microanalyses.
• Textile industry: Some monodentate phosphine ligands have good gloss and can be used as brightening agents in dye processes. Monodentate phosphine ligands are used in the dyeing of fabrics to improve the gloss of the fabric.

Classification

Due to the wide variety of monodentate phosphine ligands, they can be classified into different types according to different classification methods. Monodentate phosphine ligands can be classified into achiral monodentate phosphine ligands, planar chiral monodentate phosphine ligands, and axial chiral monodentate phosphine ligands depending on the presence or absence of chirality. The monodentate phosphine ligands can be mainly classified into simple phosphine ligands, phosphoramidite ligands, phosphonite ligands, phosphite ligands and other types of monophosphine ligands according to the atomic species bonded to the phosphorus atom.

• Simple phosphine ligand: Simple phosphine ligand refers to a monoatomic phosphine ligand in which all of the atoms bonded to the P atom are C atoms.

  Figure 1. Simple phosphine ligand

• Phosphoramidite ligand: A phosphoramidite ligand refers to a monodentate phosphine ligand having an atom bonded to a P atom, an N atom and two O atoms.

  Figure 2. Phosphoramidite ligand

• Phosphonate ligand: A phosphonate ligand refers to a monodentate phosphine ligand having an atom bonded to a P atom, a C atom, and two O atoms.

  Figure 3. Phosphoramidite ligand

• Phosphite ligand: A phosphite ligand refers to a monodentate phosphine ligand in which the atoms bonded to the P atom are all O atoms.

  Figure 4. Phosphite ligand

References

1. Li, Qian. (2018). “Synthesis, characterization, and luminescent properties of three-coordinate copper(I) halide complexes containing a carbazolyl monodentate phosphine ligand.” Journal of Coordination Chemistry 33(7), 0095-0102.
2. Chen, Bu-Lin. (2017). “Synthesis, characterization and luminescent properties of three-coordinate copper(I) halide complexes containing diphenylamino monodentate phosphine ligand” Journal of Coordination Chemistry 70(16), 2916-2928.
3. Kakizoe, Daichi. (2017), “ Photophysical properties of three coordinated copper(I) complexes bearing1,10-phenanthroline and a monodentate phosphine ligand.” Dalton Transactions 46(43), 14804-14811.