9-Phenyl-9H,9'H-[3,3']bicarbazolyl: Applications in Organic Electroluminescent Elements and its Synthesis

General Description

9-Phenyl-9H,9'H-[3,3']bicarbazolyl, a unique organic compound with two carbazole rings linked by a phenyl group, exhibits distinct chemical and physical properties. 9-Phenyl-9H,9'H-[3,3']bicarbazolyl has significant applications in organic electroluminescent elements, particularly in phosphorescent organic EL devices, due to its excellent hole transport capabilities and suitability as a phosphorescence host material in OLEDs. 9-Phenyl-9H,9'H-[3,3']bicarbazolyl is synthesized through a meticulous multi-step process with high yield and simplicity in post-processing, making it suitable for industrial production. Overall, 9-Phenyl-9H,9'H-[3,3']bicarbazolyl represents a significant advancement in materials science and organic electronics, contributing to the development of highly efficient and durable lighting and display technologies.

Figure 1. 9-Phenyl-9H,9'H-[3,3']bicarbazolyl

Overview

9-Phenyl-9H,9'H-[3,3']bicarbazolyl is a noteworthy organic compound that belongs to the carbazole family. It is characterized by the presence of two carbazole rings linked together through a phenyl group. This unique structure endows 9-Phenyl-9H,9'H-[3,3']bicarbazolyl with distinct chemical and physical properties. The phenyl substituent plays a crucial role in determining its solubility, reactivity, and potential applications. The bicarbazolyl moiety, on the other hand, contributes to its electronic properties, making 9-Phenyl-9H,9'H-[3,3']bicarbazolyl a potentially valuable building block in organic synthesis and materials science. However, a thorough understanding of its behavior and interactions with other molecules requires further investigation and experimental validation. ¹

Applications in Organic Electroluminescent Elements

9-Phenyl-9H,9'H-[3,3']bicarbazolyl, a novel organic compound, finds significant application in organic electroluminescent (EL) elements, particularly in phosphorescent organic electroluminescent devices. These devices are designed to exhibit high efficiency and durability, employing organic compounds with superior characteristics such as excellent hole injection/transport capabilities, effective confinement of triplet excitons, electron-stopping abilities, stability as thin films, and high luminous efficiency. In the construction of organic EL elements, 9-Phenyl-9H,9'H-[3,3']bicarbazolyl is utilized within the hole-transport layer, a crucial component of the device. This layer, intercalated between a pair of electrodes, plays a pivotal role in facilitating the movement of charge carriers, ensuring efficient operation of the device. The compound's carbazole ring structure, along with its substituents as described, contributes to its suitability for this application, enabling optimal hole transport within the device. Moreover, in the realm of organic light-emitting diodes (OLEDs), 9-Phenyl-9H,9'H-[3,3']bicarbazolyl derivatives serve as phosphorescence host materials in organic emission layers. These materials, when integrated into OLEDs, enhance device efficiency while simultaneously improving stability for both hole and electron transport, thereby lowering the operating voltage required for optimal performance. In summary, the incorporation of 9-Phenyl-9H,9'H-[3,3']bicarbazolyl and its derivatives in organic electroluminescent elements and OLEDs represents a significant advancement in the field, contributing to the development of highly efficient and durable lighting and display technologies. ²

Synthesis

The synthesis of 9-Phenyl-9H,9'H-[3,3']bicarbazolyl, a significant compound in materials science and organic electronics, is achieved through a meticulous multi-step process. The method begins with 3-boronic acid-9-phenylcarbazole as the primary starting material. Under the catalysis of Pd2(dba)3 and triphenylphosphine, this precursor undergoes a coupling reaction to yield 9-phenyl-3,3'-carbazole. Subsequently, utilizing PdCl2(dppf) and X·phos as catalysts, the desired 9-phenyl-9H,9'H-[3,3']bicarbazolyl compound is synthesized from 9-phenyl-3,3'-carbazole. This synthesis route is optimized to minimize the formation of byproducts, thereby enhancing the overall yield to over 91%. Additionally, the method is designed with simplicity and efficiency in post-processing, facilitating its scalability for industrial production. The detailed synthesis procedure involves several key steps: firstly, the mixing of 3-boronic acid-9-substituted carbazole, 3-bromo-carbazole, potassium carbonate, methylbenzene, ethanol, and distilled water in a reactor, followed by catalytic coupling and subsequent purification steps including vacuum distillation and filtration. Secondly, the coupling of 9-substituted-3,3'-bicarbazole with bromo-aromatic compound and potassium tert-butoxide in methylbenzene solvent, also involving catalytic coupling and purification steps. The molar ratios of reactants are carefully controlled throughout the process to ensure optimal conversion and yield, with specific ratios of 1:1.05-1.2:2.2-3 for the first step and 1:1.2-1.5:2.5-3 for the second step. This synthesis method represents a significant advancement in the production of 9-Phenyl-9H,9'H-[3,3']bicarbazolyl, offering improved efficiency, yield, and cost-effectiveness for its industrial-scale manufacture. ³

Reference

1. 9-Phenyl-9H,9'H-[3,3']bicarbazolyl. National Center for Biotechnology Information. 2024; PubChem Compound Summary for CID 59306629.

2. Yokoyama N, Nagaoka M, Togashi K, Kusano S, Takahashi E. Organic electroluminescent element. 2011; Patent Number: WO2011048822.

3. Feng HD, Wang YQ, Wu BH, Li Z, Zhang FF. Synthesis of 9,9'-disubstituted-3,3'-carbazole. 2017; Patent Number: CN106631984.

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