کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1341123 | 1500295 | 2005 | 6 صفحه PDF | دانلود رایگان |
Biradicaloid character of three Kekulé aromatic compounds containing two phenalenyl moieties is discussed on the basis of the theoretical and experimental results. DFT calculation of the compounds reveals a small HOMO–LUMO gap with a large spatial overlap between them, leading to a singlet biradical character in a ground state and an excited triplet biradical state with a small ΔES–T. Singlet biradical character for 1 (see Fig. 1) is indicated by the X-ray crystallographic analysis, which shows dimeric pairs with substantially short non-bonding contacts of ∼3.1 Å. The ESR measurements for 1 and 3 give typical spectra for triplet species and the temperature dependence of the half-field signal indicates the thermal excitation to the triplet states.
Theoretical and experimental considerations for the biradicaloid character of three phenalenyl-based compounds are described.Figure optionsDownload as PowerPoint slide
Journal: Polyhedron - Volume 24, Issues 16–17, 17 November 2005, Pages 2522–2527