Aromatic and Antiaromatic switching in 1H-Borole and 1H-Borirene: Insights from ground and triplet states

IF 2.8 3区化学 Q2 CHEMISTRY, INORGANIC & NUCLEAR

Polyhedron Pub Date : 2026-02-01 Epub Date: 2025-11-16 DOI:10.1016/j.poly.2025.117896

Tara Karampour , Morteza Rouhani , Marjan Jebeli Javan

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Abstract

Aromaticity in boron-containing heterocycles exhibits notable sensitivity to electronic excitation. In this study, we present a comprehensive analysis of the aromatic and antiaromatic behavior of 1H-borole and 1H-borirene in both their ground singlet (S₀) and first excited triplet (T₁) states using structural, magnetic, and energetic criteria. Bond length alternation (ΔBL), harmonic oscillator model of aromaticity (HOMA), nucleus-independent chemical shifts (NICS), localized orbital locator (LOL-π) maps, and isomerization stabilization energy (ISE) were all employed to assess the π-electron delocalization in these systems. The results consistently indicate an inversion of aromatic character upon excitation: 1H-borole transitions from antiaromatic to aromatic, while 1H-borirene behaves oppositely. These insights expand our understanding of excited-state aromaticity in electron-deficient heterocycles and underscore the utility of a multi-criteria approach to aromaticity evaluation.

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h -硼和h -硼烯的芳香族和反芳香族开关：来自基态和三重态的见解

含硼杂环的芳构性对电子激发表现出显著的敏感性。在这项研究中，我们使用结构，磁性和能量标准，全面分析了1h -硼烷和1h -硼烯在其接地单重态（S 0）和第一激发三重态（T 1）状态下的芳香族和反芳香族行为。利用键长互变（ΔBL）、芳香性谐振子模型（HOMA）、核无关化学位移（NICS）、定域轨道定位（LOL-π）图和异构化稳定能（ISE）来评价这些体系的π-电子离域。结果一致表明激发后芳香性质反转：1h -硼烷从反芳香转变为芳香，而1h -硼烯则相反。这些见解扩大了我们对缺乏电子杂环的激发态芳构性的理解，并强调了多标准芳构性评价方法的实用性。

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来源期刊

Polyhedron 化学-晶体学

CiteScore

4.90

自引率

7.70%

发文量

515

审稿时长

2 months

期刊介绍： Polyhedron publishes original, fundamental, experimental and theoretical work of the highest quality in all the major areas of inorganic chemistry. This includes synthetic chemistry, coordination chemistry, organometallic chemistry, bioinorganic chemistry, and solid-state and materials chemistry. Papers should be significant pieces of work, and all new compounds must be appropriately characterized. The inclusion of single-crystal X-ray structural data is strongly encouraged, but papers reporting only the X-ray structure determination of a single compound will usually not be considered. Papers on solid-state or materials chemistry will be expected to have a significant molecular chemistry component (such as the synthesis and characterization of the molecular precursors and/or a systematic study of the use of different precursors or reaction conditions) or demonstrate a cutting-edge application (for example inorganic materials for energy applications). Papers dealing only with stability constants are not considered.