4-Bromobiphenyl: Electronic Properties and Toxicity

General Description

4-Bromobiphenyl is a compound of interest in electron attachment research, particularly through Dissociative Electron Attachment (DEA) spectroscopy. Its structure influences electronic properties and anion stability, with studies showing long-lived anions detectable for approximately 40 microseconds. However, experimental conditions significantly affect outcomes, indicating variability in ion yields across different spectrometric techniques. Furthermore, 4-Bromobiphenyl activates the aryl hydrocarbon receptor (AhR), leading to toxic effects including weight loss, skin disorders, and impacts on vital organs. The compound's dual role in both molecular dynamics and health risks necessitates careful handling and monitoring in environmental and occupational contexts.

Figure 1. 4-Bromobiphenyl

Electronic Properties

4-Bromobiphenyl is a molecular compound of significant interest in the field of electron attachment research, particularly in the context of Dissociative Electron Attachment (DEA) spectroscopy. Its unique structure, characterized by the presence of bromine (Br) attached to a biphenyl backbone, influences its electronic properties and reaction dynamics. As researchers delve into the behavior of 4-Bromobiphenyl, they uncover valuable insights into molecular anion stability and the kinetic processes that occur during electron attachment events. The study of 4-Bromobiphenyl not only enhances our understanding of molecular chemistry but also provides a model for broader implications in related scientific disciplines. ¹

Formation and Stability of Molecular Anions

The formation of molecular anions from 4-Bromobiphenyl under DEA spectroscopy is a key focus of study. It has been observed that 4-Bromobiphenyl primarily generates long-lived anions, which are detectable using a static magnet mass analyzer. These anions exhibit impressive stability, persisting for approximately 40 microseconds at elevated temperatures, indicating their potential for extensive kinetic examination. Structural analyses reveal distinct configurations with C-Br bond lengths of 1.92 Å and 2.8 Å, which are crucial for understanding the stability and reactivity of the anions formed from 4-Bromobiphenyl. These structural insights pave the way for deeper investigations into electron attachment mechanisms and anion dynamics in this compound. ¹

Kinetic Processes and Experimental Variability

The kinetic properties surrounding 4-Bromobiphenyl unveil significant experimental variability in DEA outcomes when using different spectrometric techniques. For instance, experiments conducted in Ufa demonstrate a consistent presence of robust Br- negative fragments alongside stable molecular anions. In contrast, the Prague experimentation utilizing a quadrupole mass filter yields different results, highlighting how experimental conditions can markedly influence the observed ion yields. The application of kinetic equations illustrates the interplay between electron detachment and dissociation processes, emphasizing the crucial role of experimental setup in DEA studies. These insights underscore 4-Bromobiphenyl's role as a model system for studying electron attachment dynamics and molecular anion formation. The compound's stability and the variability of experimental outcomes provide valuable contributions to understanding fundamental processes in chemical physics and ion chemistry. ¹

Toxicity

Mechanism of Toxicity

4-Bromobiphenyl exerts its toxicity primarily through activation of the aryl hydrocarbon receptor (AhR). Upon binding to AhR, 4-Bromobiphenyl triggers the upregulation of various genes involved in biochemical and endocrine pathways. This activation disrupts normal cellular functions, including cell cycle regulation, morphogenesis, and oxidative stress response. Notably, genes such as CYP1A1 and CYP1A2, which encode cytochrome P-450 enzymes, are induced, further contributing to metabolic disturbances and toxicity (ATSDR, 2004). ²

Health Effects and Exposure Routes

Exposure to 4-Bromobiphenyl can result in diverse health effects. These include weight loss, skin disorders like acne, and impacts on the nervous and immune systems. Additionally, 4-Bromobiphenyl exposure may lead to adverse effects on vital organs such as the liver, kidneys, and thyroid gland (ATSDR, 2004). Routes of exposure include oral ingestion, inhalation, and dermal contact, highlighting the potential for widespread exposure through various environmental and occupational settings (ATSDR, 2004). ²

This dual impact on molecular pathways and organ systems underscores the significant health risks associated with 4-Bromobiphenyl exposure, necessitating stringent preventive measures and monitoring to mitigate its adverse effects on human health.

Reference

1. Asfandiarov NL, Pshenichnyuk SA, Rakhmeyev RG, et al. 4-Bromobiphenyl: Long-lived molecular anion formation and competition between electron detachment and dissociation. J Chem Phys. 2019; 150(11): 114304.

2. National Center for Biotechnology Information (2024). PubChem Compound Summary for CID 7101, 4-Bromobiphenyl.

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