5-(dicyclohexylphosphino)-1',3',5'-triphenyl-1,4'-Bi-1H-pyrazole
[CAS# 1021176-69-1]

Identification

• Classification: Organic raw materials >> Organic phosphine compound
• Name: 5-(dicyclohexylphosphino)-1',3',5'-triphenyl-1,4'-Bi-1H-pyrazole
• Synonyms: dicyclohexyl-[2-(1,3,5-triphenylpyrazol-4-yl)pyrazol-3-yl]phosphane
• Molecular Formula: C₃₆H₃₉N₄P
• Molecular Weight: 558.70
• CAS Registry Number: 1021176-69-1
• SMILES: C1CCC(CC1)P(C2CCCCC2)C3=CC=NN3C4=C(N(N=C4C5=CC=CC=C5)C6=CC=CC=C6)C7=CC=CC=C7

Properties

• Solubility: Sparingly Soluble (2.5E^-6 g/L) (25 ºC), Calc.^*
• Melting point: 173-174 ºC^**
• Boiling point: 729.4±60.0 ºC (760 Torr), Calc.^*
• Flash point: 394.9.0±32.9 ºC, Calc.^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software V11.02 (©1994-2022 ACD/Labs)

^** Withbroe, Gregory J.; Organic Research & Development 2008, 12(3), P480-489 CAPLUS

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H315-H319
• Precautionary Statements: P264-P280-P302+P352+P332+P313+P362+P364-P305+P351+P338+P337+P313

Discovory and Applicatios

5-(Dicyclohexylphosphino)-1',3',5'-triphenyl-1,4'-bi-1H-pyrazole is a complex organophosphorus compound that has gained attention in the field of coordination chemistry and catalysis due to its unique structure and versatile applications. The compound features a bi-pyrazole core with a dicyclohexylphosphino group attached, along with three phenyl substituents. This structural arrangement endows the molecule with both steric bulk and electronic properties that make it particularly useful in various catalytic processes.

The discovery of 5-(dicyclohexylphosphino)-1',3',5'-triphenyl-1,4'-bi-1H-pyrazole can be linked to the ongoing quest in the mid to late 20th century for novel ligands that could improve the performance of metal catalysts. Researchers recognized the potential of combining bi-pyrazole units with phosphine groups to create ligands that could provide both stability and fine-tuned electronic effects when coordinated to metal centers. The introduction of bulky dicyclohexylphosphino and triphenyl groups was a strategic design choice aimed at creating a ligand that could effectively influence catalytic processes by altering the steric and electronic environment around the metal center.

One of the primary applications of this compound lies in homogeneous catalysis, where it serves as a ligand for transition metals such as palladium, platinum, and rhodium. The bi-pyrazole structure, combined with the phosphine moiety, allows for the formation of stable, yet highly active metal complexes. These complexes are particularly valuable in cross-coupling reactions, such as Suzuki-Miyaura and Heck reactions, which are fundamental in organic synthesis, especially in the pharmaceutical industry for the construction of carbon-carbon bonds.

The presence of the dicyclohexylphosphino group in 5-(dicyclohexylphosphino)-1',3',5'-triphenyl-1,4'-bi-1H-pyrazole is particularly beneficial for catalysis. This group provides steric bulk, which can help to prevent unwanted side reactions by shielding the metal center from excessive coordination or reaction with other molecules in the reaction mixture. At the same time, the electron-donating nature of the phosphine group helps to stabilize the metal-ligand complex, enhancing the efficiency and selectivity of the catalytic process.

Beyond its use in catalysis, 5-(dicyclohexylphosphino)-1',3',5'-triphenyl-1,4'-bi-1H-pyrazole has also been explored in materials science, particularly in the development of new materials with tailored properties. The rigid, yet modifiable, structure of the bi-pyrazole core allows for the design of materials with specific electronic or optical properties. This has potential applications in the fields of electronics, where such materials could be used in the development of advanced sensors or as components in electronic devices.

The compound's versatility extends to coordination chemistry, where it has been used to create a variety of metal complexes with unique geometries and reactivities. These complexes are of interest not only for their catalytic properties but also for their potential use in the study of fundamental chemical processes, such as electron transfer and small molecule activation. The ability to fine-tune the properties of these complexes by modifying the ligand structure makes 5-(dicyclohexylphosphino)-1',3',5'-triphenyl-1,4'-bi-1H-pyrazole a valuable tool in both academic research and industrial applications.

In summary, the discovery of 5-(dicyclohexylphosphino)-1',3',5'-triphenyl-1,4'-bi-1H-pyrazole represents a significant advancement in the field of ligand design, providing chemists with a versatile tool for improving catalytic processes and developing new materials. Its unique structure, combining steric bulk and electronic tunability, makes it an important compound in the ongoing development of more efficient and selective catalytic systems.