High-spin conjugated radicals have great potential in magnetic materials and organic spintronics. However, to obtain high-spin conjugated radicals is still quite challenging due to their poor stability. We report the successful synthesis and isolation of a stable triplet conjugated diradical, 10,12-diaryldiindeno[1,2-b:2',1'-e]pyrazine (m-DIP). With the m-xylylene analogue skeleton containing electron-deficient sp -nitrogen atoms, m-DIP displays significant aromatic character within its pyrazine ring and its spin density mainly delocalizes on the meta-pyrazine unit, making it a triplet ground state conjugated diradical. Our work provides an effective "spin density tuning" strategy for stable high-spin conjugated radicals.
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http://dx.doi.org/10.1002/anie.202012989 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
School of Chemistry and Chemical Engineering, Inner Mongolia University, 235 West University Street, Hohhot, 010021, China.
Polycyclic aromatic hydrocarbons (PAHs) have attracted significant interest in material chemistry, particularly if they own extremely low band gaps and magnetic properties. However, challenges remain regarding the synthetic accessibility and energy saturation issues. In this study, we introduce NR-11, which consists of eleven aromatic rings in its main conjugation and is separately doped with two electron-rich nitrogen atoms.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Laboratoire de Chimie et Physique Quantiques, IRSAMC-CNRS-UMR 5626, Université Paul-Sabatier (Toulouse III), 31062 Toulouse, Cedex 4, France.
Recent work has documented conjugate polycyclic hydrocarbons presenting unusual properties: accepting full on-bond electron pairing, they could be considered as closed-shell architectures, but their ground-state wave function is actually a pure diradical singlet, free of any ionic component, in contrast to diradicaloids. These so-called molecules also differ from disjoint diradicals, which do not accept on-bond electron pairing, in that their singly occupied molecular orbitals (SOMOs) are spatially entangled rather than disjoint. The present work first extends the study to a broad series of architectures exhibiting the same properties, namely: they present two degenerate SOMOs in the topological Hückel Hamiltonian, and their pure diradical wave functions lead to symmetry-keeping geometries.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Center of Single-Molecule Sciences, Institute of Modern Optics, Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin, 300350, China.
High-spin polycyclic hydrocarbons (PHs) hold significant potential in organic spintronics and organic magnets. However, their synthesis is very challenging due to their extremely high reactivity. Herein, we report the successful synthesis and isolation of a kinetically blocked derivative (1) of dianthraceno[2,3-a : 3',2'-h]-s-indacene, which represents a rare persistent triplet diradical of a Kekulé PH.
View Article and Find Full Text PDFMater Horiz
December 2024
Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
Owing to their unique and tunable optoelectronic and magnetic properties, organic conjugated radicals have great potential in information storage and communication through modulating the molecular spin states. However, few electronic/spintronic devices based on these materials have been reported to date due to various intrinsic constraints such as poor material stability and processability. In this work, we have synthesized a stable singlet ground state organic conjugated diradical 5,7-dimesityl--indaceno[1,2-:7,6-']dipyridine (mNIF) with narrow band gap (1.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Department of Chemistry, National University of, Singapore, 3 Science Drive 3, 117543, Singapore.
We report a robust strategy for tuning the electronic structure and chemical stability of π-conjugated polycyclic hydrocarbons (PHs). By fusing two cyclopentadienyl rings in the peri-tetracene bay regions, we introduce antiaromatic character into the π-system, leading to unique photophysical and electronic properties. A stable mesityl-substituted dicyclopenta-peri-tetracene derivative was synthesized through stepwise formylation/intramolecular cyclization at the bay regions of the dihydro peri-tetracene precursor, followed by oxidative dehydrogenation.
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