Tris(2,4,6-trimethylphenyl)phosphine
[CAS# 23897-15-6]

Identification

• Classification: Organic raw materials >> Organic phosphine compound
• Name: Tris(2,4,6-trimethylphenyl)phosphine
• Molecular Formula: C₂₇H₃₃P
• Molecular Weight: 388.52
• CAS Registry Number: 23897-15-6
• SMILES: CC1=CC(=C(C(=C1)C)P(C2=C(C=C(C=C2C)C)C)C3=C(C=C(C=C3C)C)C)C

Properties

• Solubility: Insoluble (1.6E^-7 g/L) (25 °C), Calc.^*
• Melting Point: 185-188 °C

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software V11.02 (©1994-2013 ACD/Labs)

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H317-H319
• Safety Statements: P280-P305+P351+P338

Discovery and Applications

Tris(2,4,6-trimethylphenyl)phosphine is a versatile chemical compound that has garnered significant attention in the field of organometallic chemistry due to its unique properties and applications. Its discovery and application have highlighted its importance in various chemical processes, particularly in catalysis.

The compound Tris(2,4,6-trimethylphenyl)phosphine, often abbreviated as P(t-Bu)3, was first introduced in the 1970s as part of research efforts aimed at developing new ligands for transition metal catalysis. The ligand features a phosphorus atom bonded to three 2,4,6-trimethylphenyl groups. The bulky nature of these groups provides significant steric protection to the phosphorus center, which influences the ligand's behavior in catalytic processes.

The synthesis of Tris(2,4,6-trimethylphenyl)phosphine involves the reaction of 2,4,6-trimethylphenyl lithium or Grignard reagents with a phosphorus trichloride or a related phosphorus source. The reaction conditions are carefully controlled to ensure the formation of the tris-substituted phosphine with high purity and yield. The process typically requires precise handling of reagents and conditions to avoid side reactions and ensure the stability of the product.

One of the primary applications of Tris(2,4,6-trimethylphenyl)phosphine is in transition metal catalysis. The bulky nature of the ligand provides steric protection around the metal center, which can influence the reactivity and selectivity of catalytic processes. This makes P(t-Bu)3 a valuable ligand in various catalytic reactions, including hydrogenation, hydroformylation, and cross-coupling reactions.

In hydrogenation reactions, Tris(2,4,6-trimethylphenyl)phosphine is used as a ligand in catalysts that facilitate the reduction of unsaturated compounds. The steric bulk of the ligand can stabilize the metal center and influence the selectivity of the hydrogenation process, allowing for the efficient production of specific products.

The compound is also used in hydroformylation reactions, where it serves as a ligand in catalysts that convert alkenes into aldehydes. The ability of P(t-Bu)3 to provide a well-defined environment around the metal center enhances the efficiency and selectivity of the hydroformylation process.

In addition to these applications, Tris(2,4,6-trimethylphenyl)phosphine is employed in cross-coupling reactions, where it helps facilitate the formation of carbon-carbon bonds. The ligand's steric properties can affect the reaction outcome, leading to improved yields and selectivity in the synthesis of complex organic molecules.

The advantages of using Tris(2,4,6-trimethylphenyl)phosphine in these catalytic processes include its ability to provide steric protection and enhance the performance of metal catalysts. However, challenges associated with its use include the need for precise control of reaction conditions and the potential for ligand deactivation or competition with other ligands.

Future research into Tris(2,4,6-trimethylphenyl)phosphine may focus on exploring new applications and optimizing its use in various catalytic processes. Researchers may investigate modifications to the ligand structure or develop new derivatives to enhance its properties and expand its utility in organometallic chemistry.

References

2012. Novel Al-Based FLP Systems. *Topics in Current Chemistry*, 334.
DOI: 10.1007/128_2012_374

2009. Synthesis of 1,4-Dichloro-1,3-butadienes by Rhodium Complex Catalyzed Reaction of Terminal Alkynes with Trichloroacetyl Chloride. *The Journal of Organic Chemistry*, 74(22).
DOI: 10.1021/jo902088p

1979. Steric dominance of the facile cyclometallation of trimesitylphosphine and trimesitylarsine. *Transition Metal Chemistry*, 4(3).
DOI: 10.1007/bf00619068