Non-alternant, non-benzenoid π-conjugated polycyclic hydrocarbons (PHs) are expected to exhibit very different electronic properties from all-benzenoid PHs. Reported herein are the syntheses and physical properties of four derivatives of two azulene-fused s-indacene isomers, the diazuleno[2,1-a:2',1'-g]-s-indacene (DAI-1) and diazuleno[2,1-a:1',2'-h]-s-indacene (DAI-2). The backbone of both isomers contains 28π electrons and is a 7-5-5-6-5-5-7 fused ring system. X-ray crystallographic analysis, NMR spectra, and theoretical calculations (ACID, NICS) reveal a structure with two aromatic azulene units fused with a central anti-aromatic s-indacene moiety. All compounds exhibit open-shell diradical character and are magnetically active, but the derivatives of DAI-2 show larger radical character than the respective ones of DAI-1. Their dications were isolated in crystalline form and all experimental and theoretical analyses disclose a shift of local (anti)aromaticity along the backbone, with two aromatic tropylium rings at the termini.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/anie.201810220 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Unveiling the Interplay between Dopamine-like Molecules and Β-Amyloid Peptide: A Combined Molecular Dynamic and DFT Approach.
Comb Chem High Throughput Screen
January 2025
Department of Chemistry, Mashhad Branch, Islamic Azad University, Mashhad, Iran.
Aims: This study aims explore the impact of catechol, dopamine, and L-DOPA on the stability and toxicity of β-amyloid peptides, which play a key role in the neurodegenerative process of Alzheimer's disease, to assess their potential as therapeutic agents.
Background: Alzheimer's disease is marked by the aggregation of β-amyloid peptides, which contribute to neurodegeneration. Exploring how various compounds interact with β-amyloid peptides can offer valuable insights into potential therapeutic strategies.
Boron-Doped Molecular Carbons Bearing a Formal Boron-Inserted Pentalene: Synthesis, Electronic Structures and Properties.
Org Lett
December 2024
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China.
Two boron-doped molecular carbons (BMCs), featuring one formal boron-inserted pentalene (BP) embedded into the CB or CB polycyclic π-skeleton, were successfully synthesized. Despite their small-size conjugated structures, both of them exhibit unusual broad light absorption, narrow energy gaps, and electron-accepting ability, as well as local antiaromaticity with pseudo 4π electrons. As disclosed, these intriguing physical properties are significantly contributed by the boron atom and pentagonal ring in the BP substructure, thus demonstrating the importance of such BP incorporation into polycyclic π-systems.
View Article and Find Full Text PDFAnalysis of Interaction Features of Cyclo[13]carbon with Small Molecules and Formation Mechanism of Its Dimer.
J Org Chem
December 2024
School of Physics and Electronics, Shandong Normal University, Jinan, Shandong 250358, China.
The newly discovered cyclo[13]carbon, the first artificially synthesized odd-numbered carbon ring, is an intriguing carbon isomer that provides a valuable subject for studying low-symmetry carbon materials. In this work, we employed first-principles calculations to explore the geometric structure and electronic properties of cyclo[13]carbon through various techniques such as vibrational mode analysis, bond order analysis, spin density analysis, electron localization analysis, electrostatic potential and van der Waals potential analysis, visualization of weak interactions, and energy decomposition analysis. We investigated the interaction characteristics of cyclo[13]carbon with small molecules and examined its dimer formation mechanism and dynamics features using ab initio molecular dynamics.
View Article and Find Full Text PDFHighly Strained, Fully π-Conjugated Porphyrin Cyclophanes: Template-free Synthesis and Global Aromaticity.
Angew Chem Int Ed Engl
October 2024
Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore.
Article Synopsis
- The study focuses on creating porphyrin-based nanohoops, rings, and cages, which are difficult to synthesize but have desirable properties.
- The authors describe a template-free method to synthesize a unique bithiophene-bridged porphyrin cyclophane, revealing its strained structure and electronic characteristics through X-ray analysis.
- The resulting compounds exhibit interesting aromatic properties and reactivity, with the dication being globally aromatic and able to relieve strain through nucleophilic addition with chloride.
Stabilization of the Compressed Planar Benzene Dianion in Inverse-Sandwich Rare Earth Metal Complexes.
Angew Chem Int Ed Engl
October 2024
Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan, 48824, USA.
For the first time, the capture of the planar antiaromatic parent benzene dianion in between two trivalent rare earth (RE) metal cations (RE), each stabilized by two guanidinate ligands, is reported. The synthesized inverse-sandwich complexes [{(MeSi)NC(NPr)}RE](μ-η : η-CH), (RE=Y (1), Dy (2), and Er (3)) were crystallized from aprotic solvents and feature a remarkably planar parent benzene dianion, previously not encountered for any metal ion prone to low or absent covalency. The -2 charge localization at the benzene ligand was deduced from the results obtained by single-crystal X-ray diffraction analyses, spectroscopy, magnetometry, and Density Functional Theory (DFT) calculations.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!