2-(4-Bromophenyl)naphthalene: Properties & Applications

2-(4-Bromophenyl)naphthalene is a halogenated biaryl building block widely used in organic synthesis, particularly as a versatile intermediate in cross-coupling reactions and the construction of extended π-conjugated frameworks.

Molecular Formula

C₁₆H₁₁Br

Molecular Weight

307.17 g/mol

CAS Number

3540-95-2

Functional Group

Aryl bromide (C–Br bond at para position of pendant phenyl ring)

Core Structure

Naphthalene fused ring system linked at C-2 to a 4-bromophenyl group

Primary Use

Intermediate in palladium-catalyzed cross-coupling and π-conjugated material synthesis

Chemical Structure and Physicochemical Properties

2-(4-Bromophenyl)naphthalene (CAS 3540-95-2, Aladdin SKU B152876) consists of a naphthalene ring system connected at its 2-position to a phenyl ring bearing a bromine substituent at the para (4-) position. The molecular formula is C₁₆H₁₁Br with a molecular weight of approximately 307.17 g/mol. The molecule belongs to the class of halogenated polycyclic aromatic hydrocarbons (PAHs) and features an extended, planar π-conjugated system arising from the biaryl linkage.

The compound is typically a white to off-white crystalline solid at room temperature. The presence of the electron-withdrawing bromine atom on the pendant phenyl ring modestly influences the electron density across the conjugated framework. The aryl C–Br bond is the primary reactive site, conferring excellent reactivity in metal-catalyzed cross-coupling protocols. The compound should be stored in a cool, dry environment away from light and moisture to maintain stability.

Synthesis and Role as a Synthetic Intermediate

2-(4-Bromophenyl)naphthalene can be accessed via classical biaryl coupling strategies. One common synthetic route involves a Suzuki–Miyaura cross-coupling reaction between 2-naphthaleneboronic acid and 1-bromo-4-iodobenzene (or a related dihalide), using a palladium catalyst. Alternatively, it may be prepared through direct C–H functionalization or Grignard-based approaches, depending on the desired selectivity and scale.

As a synthetic building block, the compound serves as an aryl bromide partner in subsequent palladium-catalyzed reactions (Suzuki, Negishi, Buchwald–Hartwig, and Heck couplings), enabling the introduction of diverse functional groups at the brominated position. This versatility makes it a valuable intermediate for constructing more complex biaryl, triaryl, or heteroaromatic architectures used in pharmaceutical, agrochemical, and materials research.

Research and Industrial Applications

Organic Electronics and Materials Science: The extended π-system of 2-(4-Bromophenyl)naphthalene and its derivatives makes this compound class relevant to organic semiconductor research. Biaryl compounds with naphthalene cores have been investigated as components of organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs), and fluorescent probes, owing to their favorable charge-transport and photophysical characteristics.

Pharmaceutical and Medicinal Chemistry: Naphthalene-phenyl biaryl scaffolds appear in various bioactive molecules. 2-(4-Bromophenyl)naphthalene provides a handle for diversification through cross-coupling, facilitating structure–activity relationship (SAR) studies and library synthesis. The reactive aryl bromide allows facile introduction of boronic acids, amines, alkyls, and other pharmacophoric elements.

Supramolecular and Coordination Chemistry: Planar polycyclic aromatic building blocks are employed in constructing supramolecular assemblies, metal–organic frameworks (MOFs), and host–guest systems. The biaryl unit's conformational flexibility around the C–C bond and its π-stacking propensity are exploited in crystal engineering applications.

Handling, Safety, and Storage Guidelines

As with all organobromine compounds, standard laboratory safety precautions should be observed when working with 2-(4-Bromophenyl)naphthalene. Researchers should consult the Safety Data Sheet (SDS) provided by Aladdin Scientific before use. General guidelines include working in a well-ventilated fume hood, wearing appropriate personal protective equipment (PPE) such as nitrile gloves, lab coat, and safety goggles, and avoiding inhalation of dust or vapors.

The compound should be stored in a tightly sealed container under dry conditions at room temperature or as specified on the product label. It is advisable to keep it away from strong oxidizing agents and sources of ignition. Waste disposal must comply with local, institutional, and governmental regulations for halogenated organic waste streams. Refer to the current SDS for specific hazard classifications and first-aid measures.

Frequently asked questions

What is 2-(4-Bromophenyl)naphthalene primarily used for in organic synthesis?

It is primarily used as an aryl bromide building block in palladium-catalyzed cross-coupling reactions, including Suzuki–Miyaura, Negishi, Heck, and Buchwald–Hartwig couplings. These reactions allow chemists to attach diverse functional groups at the bromine-bearing carbon, enabling the synthesis of complex biaryl and polycyclic aromatic compounds for pharmaceutical, materials, and agrochemical research.

What are the key physical properties of 2-(4-Bromophenyl)naphthalene?

2-(4-Bromophenyl)naphthalene has the molecular formula C₁₆H₁₁Br and a molecular weight of approximately 307.17 g/mol. It is typically a white to off-white crystalline solid at room temperature, featuring an extended planar biaryl π-system. Specific melting point, solubility, and spectroscopic data should be confirmed from the product's certificate of analysis (CoA) or SDS.

How should 2-(4-Bromophenyl)naphthalene be stored to ensure stability?

The compound should be stored in a tightly sealed container in a cool, dry location away from direct light, moisture, and strong oxidizing agents. Follow the specific storage conditions indicated on the product label and SDS provided by Aladdin Scientific to maintain purity and prevent degradation over time.

Is 2-(4-Bromophenyl)naphthalene relevant to organic electronics research?

Yes. Naphthalene-based biaryl compounds are of interest in organic electronics due to their extended π-conjugation, which supports charge transport and photophysical performance. 2-(4-Bromophenyl)naphthalene serves as a precursor to more elaborate π-conjugated architectures investigated in OLEDs, OFETs, and fluorescent probe development.

References

1. Miyaura, N.; Suzuki, A. Palladium-Catalyzed Cross-Coupling Reactions of Organoboron Compounds. Chem. Rev. 1995, 95, 2457–2483. doi:10.1021/cr00039a007
2. Johansson Seechurn, C. C. C.; Kitching, M. O.; Colacot, T. J.; Snieckus, V. Palladium-Catalyzed Cross-Coupling: A Historical Contextual Perspective to the 2010 Nobel Prize. Angew. Chem. Int. Ed. 2012, 51, 5062–5085. doi:10.1002/anie.201107017
3. Anthony, J. E. Functionalized Acenes and Heteroacenes for Organic Electronics. Chem. Rev. 2006, 106, 5028–5048. doi:10.1021/cr050966z

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