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Updated: Sep 13, 2025
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Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
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Peri-Fused Six-Membered Cyclic Nitrenium Ions (PCNIs): Electronic Structure and Aromaticity
Lahu N Dayare1, Astha Gupta1, Kanika Manchanda2
1Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), S. A. S. Nagar, Punjab, India.
Journal of Computational Chemistry
|July 29, 2025
Summary
Six-membered cyclic nitrenium ions (PCNIs) are rare and exhibit unique electronic properties. This study designed new PCNIs, identifying stable, aromatic, and highly Lewis acidic compounds.
Area of Science:
- Organic Chemistry
- Computational Chemistry
Background:
- Cyclic nitrenium ions (CNIs) are typically found in five- and seven-membered rings.
- Six-membered cyclic nitrenium ions (PCNIs) are rare and their electronic properties differ from other CNIs.
- Known PCNIs are non-aromatic and act as nitrogen Lewis acids.
Purpose of the Study:
- To perform electronic structure analysis on newly designed PCNIs.
- To understand the characteristic electronic features of PCNIs.
- To identify PCNIs with enhanced electronic stability and Lewis acidity.
Main Methods:
- Computational electronic structure analysis.
- Design and evaluation of several PCNI analogs.
- Assessment of Lewis acidity using hydride ion affinity (HIA), fluoride ion affinity (FIA), ΔHPMe3, and ΔHNHC values.
Main Results:
- Identified novel PCNIs with significantly enhanced electronic stability.
- Quantified Lewis acidic character of known and designed PCNIs.
- Discovered several PCNI systems exhibiting aromaticity in all three rings with negative NICS(1) values.
Conclusions:
- Newly designed PCNIs possess unique electronic properties and high Lewis acidity.
- Aromaticity and enhanced stability were achieved in specific PCNI designs.
- This work expands the understanding of six-membered cyclic nitrenium ions and their potential applications.
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