Tris(2-thienyl)phosphine
[CAS# 24171-89-9]

Identification

• Classification: Organic raw materials >> Organic phosphine compound
• Name: Tris(2-thienyl)phosphine
• Synonyms: Tri-2-thienylphosphine
• Molecular Formula: C₁₂H₉PS₃
• Molecular Weight: 280.37
• CAS Registry Number: 24171-89-9
• EC Number: 246-059-8
• SMILES: C1=CSC(=C1)P(C2=CC=CS2)C3=CC=CS3

Properties

• Solubility: Insoluble (1.9E^-4 g/L) (25 °C), Calc.^*
• Melting Point: 28-30 °C
• Flash Point: 25 °C

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software V11.02 (©1994-2014 ACD/Labs)

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319

Discovery and Applications

Tris(2-thienyl)phosphine is a notable chemical compound in the realm of organometallic chemistry and catalysis, recognized for its distinctive properties and applications. The compound has gained prominence due to its effectiveness in various catalytic processes, contributing to advancements in both synthetic and industrial chemistry.

The discovery of Tris(2-thienyl)phosphine dates back to the early 1980s, during a period of intense research into new phosphine ligands for transition metal catalysis. The ligand features a phosphorus atom coordinated to three 2-thienyl groups, which are aromatic thiophene rings. The introduction of thiophene groups in place of the more common phenyl groups imparts unique electronic and steric properties to the ligand, making it a valuable tool in catalysis.

The synthesis of Tris(2-thienyl)phosphine involves the reaction of 2-thienyl lithium or Grignard reagents with phosphorus trichloride or a similar phosphorus source. This reaction is typically carried out in an inert atmosphere to prevent oxidation or decomposition of the reactants. The conditions are optimized to ensure high yield and purity of the tris-substituted phosphine, which is crucial for its effectiveness in catalytic applications.

One of the primary applications of Tris(2-thienyl)phosphine is in the field of homogeneous catalysis. The ligand is used to create catalysts for a variety of reactions, including hydrogenation, hydroformylation, and cross-coupling reactions. The thiophene rings in Tris(2-thienyl)phosphine influence the electronic properties of the metal center, allowing for enhanced reactivity and selectivity in these processes.

In hydrogenation reactions, Tris(2-thienyl)phosphine is used to support metal catalysts that facilitate the reduction of unsaturated compounds. The presence of thiophene rings can affect the interaction between the metal and the substrate, leading to improved catalytic performance and selectivity.

The compound is also employed in hydroformylation reactions, where it helps create catalysts for the conversion of alkenes into aldehydes. The thiophene-based ligand contributes to the efficiency and selectivity of the hydroformylation process by influencing the coordination environment of the metal center.

In cross-coupling reactions, Tris(2-thienyl)phosphine serves as a ligand that enhances the formation of carbon-carbon bonds. The unique electronic properties imparted by the thiophene rings can lead to higher yields and better selectivity in the synthesis of complex organic molecules.

The advantages of using Tris(2-thienyl)phosphine include its ability to provide a unique electronic environment around the metal center, which can lead to improved catalytic properties. However, challenges associated with its use include the need for careful handling to avoid oxidation and ensure stability in reaction conditions.

Future research on Tris(2-thienyl)phosphine may focus on exploring new catalytic applications and optimizing the performance of existing catalysts. Researchers may also investigate modifications to the ligand structure to enhance its properties or develop new derivatives with improved reactivity and selectivity.

References

Sergey P. Tunik, Igor O. Koshevoy, Anthony J. Poë, David H. Farrar, Ebbe Nordlander, Matti Haukka and Tapani A. Pakkanen. Chiral hexarhodium carbonyl clusters containing heterobidentate phosphine ligands; a structural and reactivity study, Dalton Trans., 2003, 0, 2457.