Počet záznamů: 1
p-Carborane Conjugation in Radical Anions of Cage-Cage and Cage-Phenyl Compounds
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SYSNO ASEP 0489518 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název p-Carborane Conjugation in Radical Anions of Cage-Cage and Cage-Phenyl Compounds Tvůrce(i) Cook, A. R. (US)
Valášek, Michal (UOCHB-X)
Funston, A. M. (US)
Poliakov, P. (US)
Michl, Josef (UOCHB-X) RID, ORCID
Miller, J. R. (US)Zdroj.dok. Journal of Physical Chemistry A. - : American Chemical Society - ISSN 1089-5639
Roč. 122, č. 3 (2018), s. 798-810Poč.str. 13 s. Jazyk dok. eng - angličtina Země vyd. US - Spojené státy americké Klíč. slova mixed valence molecules ; electron transfer ; aromatic hydrocarbons Vědní obor RIV CF - Fyzikální chemie a teoretická chemie Obor OECD Physical chemistry Institucionální podpora UOCHB-X - RVO:61388963 UT WOS 000423653100007 EID SCOPUS 85041180410 DOI 10.1021/acs.jpca.7b10885 Anotace Optical electron transfer (intervalence) transitions in radical anions of p-carborane oligomers attest to delocalization of electrons between two p-carboranes cages or a p-carborane and a phenyl ring. Oligomers of the 12 vertex p-carborane (C2B10H12) cage, [12], with up to 3 cages were synthesized, as well as p-carboranes with one or two trimethylsilylphenyl groups, [6], attached to the carbon termini. Pulse radiolysis in tetrahydrofuran produced radical anions, determined redox potentials by equilibria and measured their absorption spectra. Density functional theory computations provided critical insight into the optical electron transfer bands and electron delocalization. One case, [6-12-6], showed both Robin Day class II and III transitions. The class III transition resulted from a fully delocalized excess electron across both benzene rings and the central p-carborane, with an electronic coupling H-ab = 0.46 eV between the cage and either benzene. This unprecedented finding shows that p-carborane bridges are not simply electron withdrawing insulators. In other cases with more than similar to 1/2 of the excess electron localized on a [12], large cage distortions were triggered, producing a partially open cage with a nido-like structure. This resulted in class II transitions with similar H-ab but massive reorganization energies. The computations also predicted delocalization in radical cations, but complexities in cation formation allowed only tentative experimental support of the predictions. The results with anions provide clear evidence for carborane conjugation that might be exploited in molecular wire materials, which are classically composed of all pi-conjugated molecules. Pracoviště Ústav organické chemie a biochemie Kontakt asep@uochb.cas.cz ; Kateřina Šperková, Tel.: 232 002 584 ; Jana Procházková, Tel.: 220 183 418 Rok sběru 2019
Počet záznamů: 1