Diphenyl[4-(phenylthio)phenyl]sulfonium Tetrakis(pentafluorophenyl)borate
[CAS# 203573-06-2]

Identification

• Classification: Organic raw materials >> Organoboron compounds
• Name: Diphenyl[4-(phenylthio)phenyl]sulfonium Tetrakis(pentafluorophenyl)borate
• Molecular Formula: C₄₈H₁₉BF₂₀S₂
• Molecular Weight: 1050.57
• CAS Registry Number: 203573-06-2
• SMILES: C1(=C(C(=C(C(=C1F)F)[B-](C2=C(C(=C(C(=C2F)F)F)F)F)(C3=C(C(=C(C(=C3F)F)F)F)F)C4=C(C(=C(C(=C4F)F)F)F)F)F)F)F.C5=CC=CC(=C5)SC6=CC=C(C=C6)[S+](C7=CC=CC=C7)C8=CC=CC=C8

Properties

• Melting point: 142 °C

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319
• Safety Statements: P264-P280-P302+P352+P332+P313-P337+P313-P362+P264

Discovery and Applications

Diphenyl[4-(phenylthio)phenyl]sulfonium tetrakis(pentafluorophenyl)borate is a high-efficiency photoinitiator used in cationic polymerization. This compound belongs to the family of sulfonium salts and is known for its ability to rapidly initiate polymerization when exposed to ultraviolet (UV) light. Its structure consists of a sulfonium cation with two phenyl groups and a phenylthio substituent on one phenyl ring. The counteranion, tetrakis(pentafluorophenyl)borate, enhances the stability and solubility of the compound in organic media, making it highly effective in UV-curable systems.

The development of sulfonium-based photoinitiators, including diphenyl[4-(phenylthio)phenyl]sulfonium salts, has been driven by the need for faster and more efficient polymerization processes in industrial applications. Research into cationic photoinitiators demonstrated that sulfonium salts are particularly suitable for initiating the polymerization of epoxy resins, vinyl ethers, and other monomers that undergo cationic curing mechanisms. The compound's photoinitiation capabilities arise from its ability to generate a reactive species upon exposure to UV light, which triggers the polymerization of nearby monomers.

One of the primary applications of diphenyl[4-(phenylthio)phenyl]sulfonium tetrakis(pentafluorophenyl)borate is in the production of UV-curable coatings. These coatings are widely used in industries such as electronics, automotive, and packaging due to their excellent durability, resistance to chemicals, and ability to cure rapidly under UV light. The fast-curing nature of this photoinitiator allows for increased efficiency in manufacturing processes, reducing the time required for coatings to harden and increasing production throughput.

In addition to coatings, this compound is also employed in the formulation of UV-curable adhesives and inks. In the adhesives sector, it is used for bonding components in electronics, medical devices, and optical systems, where precise and strong adhesion is essential. The rapid curing enabled by the photoinitiator ensures that the adhesive sets quickly, improving assembly speed and reducing processing times. Similarly, in UV-curable inks, the compound helps produce high-quality, fast-drying inks that are resistant to smudging and fading. These inks are widely used in printing applications for packaging, labeling, and graphics.

The presence of the tetrakis(pentafluorophenyl)borate anion plays a crucial role in the performance of diphenyl[4-(phenylthio)phenyl]sulfonium salts. This anion is weakly coordinating, which facilitates the rapid generation of reactive cationic species during the photopolymerization process. Its bulky, electron-withdrawing nature also contributes to the stability and solubility of the photoinitiator in various organic formulations, making it suitable for a wide range of applications.

The discovery and synthesis of diphenyl[4-(phenylthio)phenyl]sulfonium tetrakis(pentafluorophenyl)borate were part of broader efforts to develop photoinitiators with enhanced solubility, stability, and efficiency in initiating polymerization reactions. The introduction of phenylthio and phenyl groups to the sulfonium structure improves the compound’s performance, particularly in demanding environments where high reactivity and stability are required.

References

none