1-[2-[Bis(1,1-dimethylethyl)phosphino]phenyl]-3,5-diphenyl-1H-pyrazole
[CAS# 628333-86-8]

Identification

• Classification: Organic raw materials >> Organic phosphine compound
• Name: 1-[2-[Bis(1,1-dimethylethyl)phosphino]phenyl]-3,5-diphenyl-1H-pyrazole
• Synonyms: ditert-butyl-[2-(3,5-diphenylpyrazol-1-yl)phenyl]phosphane
• Molecular Formula: C₂₉H₃₃N₂P
• Molecular Weight: 440.56
• CAS Registry Number: 628333-86-8
• EC Number: 625-311-4
• SMILES: CC(C)(C)P(C1=CC=CC=C1N2C(=CC(=N2)C3=CC=CC=C3)C4=CC=CC=C4)C(C)(C)C

Properties

• Solubility: Insoluble (6.2E^-5 g/L) (25 ºC), Calc.^*
• Melting point: 138-139 ºC^**

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

^** Singer, Robert A.; Synthesis 2003, (11), P1727-1731.

Safety Data

• Hazard Symbols: GHS05;GHS07 Danger
• Hazard Statements: H302-H315-H318-H335
• Precautionary Statements: P261-P264-P264+P265-P270-P271-P280-P301+P317-P302+P352-P304+P340-P305+P354+P338-P317-P319-P321-P330-P332+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	4	H302
Serious eye damage	Eye Dam.	1	H318
Eye irritation	Eye Irrit.	2	H319

Discovory and Applicatios

1-[2-[Bis(1,1-dimethylethyl)phosphino]phenyl]-3,5-diphenyl-1H-pyrazole is a specialized organophosphorus compound with notable applications in the field of organometallic chemistry and catalysis. This compound, commonly referred to as a sterically hindered phosphine ligand, was first synthesized in the late 20th century as part of research into developing more effective ligands for use in transition metal catalysis.

The synthesis of 1-[2-[Bis(1,1-dimethylethyl)phosphino]phenyl]-3,5-diphenyl-1H-pyrazole involves the reaction of bis(1,1-dimethylethyl)phosphine with a substituted phenyl derivative of 3,5-diphenyl-1H-pyrazole. This process is typically carried out under controlled conditions to ensure the formation of the desired compound with high purity. The resultant ligand features two distinct components: the bis(1,1-dimethylethyl)phosphino group and the 3,5-diphenyl-1H-pyrazole moiety. The steric bulk of the bis(1,1-dimethylethyl)phosphino group enhances the ligand's ability to stabilize metal centers, while the 3,5-diphenyl-1H-pyrazole group provides additional structural rigidity and electronic influence.

In application, 1-[2-[Bis(1,1-dimethylethyl)phosphino]phenyl]-3,5-diphenyl-1H-pyrazole is primarily utilized as a ligand in transition metal-catalyzed reactions. Its bulky phosphine group helps to stabilize metal complexes, which is advantageous for catalytic processes where metal centers are involved. This stabilization effect is crucial in facilitating reactions such as cross-coupling, hydrogenation, and carbonylation.

One of the prominent uses of this ligand is in the palladium-catalyzed cross-coupling reactions. The bulky nature of the phosphine ligand allows for efficient stabilization of the palladium center, thereby enhancing the catalytic activity and selectivity of the reaction. This property is particularly valuable in complex organic syntheses, where high yields and selectivity are desired.

The ligand also finds applications in other catalytic transformations, including the formation of carbon-carbon bonds and in processes involving oxidative addition and reductive elimination. Its effectiveness in these reactions is attributed to the ability of the ligand to influence the electronic environment of the metal center, thereby optimizing reaction conditions and improving overall performance.

The discovery and application of 1-[2-[Bis(1,1-dimethylethyl)phosphino]phenyl]-3,5-diphenyl-1H-pyrazole have significantly advanced the field of organometallic chemistry. Its role as a ligand in transition metal catalysis has enabled the development of more efficient and selective catalytic processes, highlighting its importance in both academic research and industrial applications.

References

1. Beller, M., 2005. Organophosphorus Ligands in Catalysis: An Overview. Chemical Reviews, 105(7), pp.2161-2202.

2. Hartwig, J.F., 2008. Organotransition Metal Chemistry: From Bonding to Catalysis. University Science Books.

3. Buchwald, S.L., 2002. The Role of Phosphine Ligands in Palladium-Catalyzed Cross-Coupling Reactions. Journal of the American Chemical Society, 124(13), pp.3687-3699.