Dibenzoheptazethrene Isomers with Different Biradical Characters: An Exercise of Clar's Aromatic Sextet Rule in Singlet Biradicaloids.
Clar's aromatic sextet rule has been widely used for the prediction of the reactivity and stability of polycyclic aromatic hydrocarbons with a closed-shell electronic configuration. Recent advances in open-shell biradicaloids have shown that the number of aromatic sextet rings plays an important rol...
| Publicado en: | Journal of the American Chemical Society Vol. 135; no. 48; pp. 18229 - 18237 |
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| Autores principales: | , , , , , , , , , , , , , , , |
| Formato: | Artículo |
| Publicado: |
American Chemical Society
12/4/2013
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=93312311&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 93312311 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 12/4/2013 vid: 135 iid: 48 pid: 997 pub: American Chemical Society artinfo: ui: 93312311 10.1021/ja410279j ppf: 18229 ppct: 8 formats: tig: atl: Dibenzoheptazethrene Isomers with Different Biradical Characters: An Exercise of Clar's Aromatic Sextet Rule in Singlet Biradicaloids. aug: au: Zhe Sun Sangsu Lee Kyu Hyung Park Xiaojian Zhu Wenhua Zhang Bin Zheng Pan Hu Zebing Zeng Soumyajit Das Yuan Li Chunyan Chi Run-Wei Li Kuo-Wei Huang Jun Ding Dongho Kim Jishan Wu affil: Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543 Singapore Department of Chemistry, Yonsei University, Seoul 120-749, Korea Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China Institute of Materials Research and Engineering, A*STAR, 3 Research Link, 117602 Singapore Division of Physical Science and Engineering and KAUST Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia Department of Materials Science & Engineering, National University of Singapore, 119260 Singapore su: Hydrocarbons Isomers Nuclear magnetic resonance Electron paramagnetic resonance spectroscopy X-ray crystallography Density functional theory sug: subj: Hydrocarbons Isomers Nuclear magnetic resonance Electron paramagnetic resonance spectroscopy X-ray crystallography Density functional theory ab: Clar's aromatic sextet rule has been widely used for the prediction of the reactivity and stability of polycyclic aromatic hydrocarbons with a closed-shell electronic configuration. Recent advances in open-shell biradicaloids have shown that the number of aromatic sextet rings plays an important role in determination of their ground states. In order to test the validity of this rule in singlet biradicaloids, the two soluble and stable dibenzoheptazethrene isomers DBHZ1 and DBHZ2 were prepared by different synthetic approaches and isolated in crystalline form. These two molecules have different numbers of aromatic sextet rings in their respective biradical resonance forms and thus are expected to exhibit varied singlet biradical character. This assumption was verified by different experimental methods, including nuclear magnetic resonance (NMR), electron spin resonance (ESR), superconducting quantum interference device (SQUID), steady-state and transient absorption spectroscopy (TA), and X-ray crystallographic analysis, assisted by unrestricted symmetry-broken density functional theory (DFT) calculations. DBHZ2, with more aromatic sextet rings in the biradical form, was demonstrated to possess greater biradical character than DBHZ1; as a result, DBHZ2 exhibited an intense one-photon absorption (OPA) in the near-infrared region (λ = 804 nm) and a large two-photon absorption (TPA) cross-section (σ = 2800 GM at 1600 nm). This investigation together with previous studies indicates that Clar's aromatic sextet rule can be further extended to the singlet biradicaloids to predict their ground states and singlet biradical characters. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2013 holdings: @attributes: islocal: N |
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