Naphthalene derivatives: properties, synthesis and applications

Naphthalene derivatives are a class of organic compounds based on the naphthalene ring structure. Due to their unique chemical structure and physical properties, they have shown important application value in many fields. Naphthalene itself is a white crystalline solid and belongs to polycyclic aromatic hydrocarbons, and its derivatives show rich and diverse properties and functions by introducing different functional groups on the naphthalene ring.

Properties of naphthalene derivatives

Optical properties: Many naphthalene derivatives have good fluorescence properties. For example, naphthalene dyes have a rigid plane and a large π-electron conjugated system, which gives them high quantum yield and excellent photostability. Naphthalene-based fluorescent probes show excellent sensing and selectivity for anions and cations due to their hydrophobicity, and can also be used for the detection of target biomolecules.

Chemical stability: Some naphthalene derivatives have good chemical stability. For example, the oxygen-resistant naphthalene derivatives prepared by the research team of the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, as positive active molecules in aqueous organic flow batteries, can still stably cycle for more than 600 cycles (more than 20 days) under the condition of continuous air blowing into the positive electrolyte.

Solubility: The solubility of naphthalene derivatives can be adjusted by introducing specific functional groups. For example, naphthoquinone derivatives containing dimethylamine functional groups can improve the solubility of naphthoquinone molecules, while protecting the molecular active center and enhancing the stability of high-concentration electrolytes.

Synthesis of naphthalene derivatives

Transition metal catalyzed synthesis: For example, the use of a stable ruthenium catalyst Ru (benzene)-(OPiv)₂ can achieve the aldehyde-directed ortho-alkylation reaction of 1-naphthaldehyde with alkyl iodide. This reaction does not require external oxidants or additives, and can introduce a variety of primary and secondary alkyl groups into the naphthalene ring, with good functional group compatibility.

In situ electrochemical oxidation synthesis: Using hydroxynaphthalene as a substrate, a strategy combining chemical synthesis and electrochemical synthesis can be used to prepare multi-substituent-modified naphthoquinone active molecules. This method is simple and efficient, does not require a complex separation and purification process, and reduces the cost of synthesis.

Application of naphthalene derivatives

Medical field: Naphthalene derivatives are important drug resources. Many naphthalene compounds have biological activity and can be used to develop various drugs, such as specific drugs for the treatment of certain diseases. Their mechanism of action may be related to the interaction of the naphthalene ring structure with biomolecules.

Materials Science: Due to their good optical properties and chemical stability, naphthalene derivatives can be used to construct organic electronic devices. For example, they can be used as organic solid laser dyes, and their smaller energy gap and enhanced stability help improve device performance.

Battery Field: Naphthalene derivatives can be used in aqueous organic flow batteries. For example, oxygen-resistant naphthalene derivatives as positive electrode active molecules have excellent air stability, which can make the battery cycle stably, and by amplifying the synthesis process, kilogram-level preparation can be achieved, which helps to promote the scale and practical application of aqueous organic flow batteries.

Other Fields: Naphthalene derivatives can also be used as wetting agents, surfactants and pesticides. Their application in these fields is mainly due to the physicochemical properties of their molecular structure that can be adjusted, such as surface activity.

Conclusion

Naphthalene derivatives play an important role in many fields such as medicine, materials science, and batteries due to their unique properties and diverse synthesis methods. As research continues to deepen, it is expected that more naphthalene derivatives with excellent performance will be developed, and their application scope will be further expanded, providing more possibilities and innovative ideas for the development of various fields.