Muecke, Philipp and Zabel, Manfred and Edge, Ruth and Collison, David and Clement, Sebastien and Zalis, Stanislav and Winter, Rainer F. (2011) Electron delocalization in vinyl ruthenium substituted cyclophanes: Assessment of the through-space and the through-bond pathways. JOURNAL OF ORGANOMETALLIC CHEMISTRY, 696 (20). pp. 3186-3197. ISSN 0022-328X, 1872-8561
Full text not available from this repository. (Request a copy)Abstract
Pseudo-para[2.2]paracyclophane- and [2.1]orthocyclophane-bridged diruthenium complexes 2 and 3 with two interlinked electroactive styryl ruthenium moieties have been prepared and investigated. Both complexes undergo two reversible consecutive one-electron oxidation processes which are separated by 270 or 105 mV. Stepwise electrolysis of the neutral complexes to first the mixed-valent radical cations and then the dioxidized dications under IR monitoring reveal incremental shifts of the charge-sensitive Ru(CO) bands and allow for an assignment of their radical cations as moderately or very weakly coupled mixed-valent systems of class II according to Robin and Day. Ground-state delocalization in the mixed-valent forms of these complexes as based on the CO band shifts is considerably larger for the "closed" paracyclophane as for the "half-open" orthocyclophane. Experimental findings are backed by the calculated IR band patterns and spin density distributions for radical cations of slightly simplified model complexes 2Me(.+) and 3Me(.+) with the (PPr3)-Pr-i ligands replaced by PMe3. Radical cations 2(.+) and 3(.+) feature a characteristic NIR band that is neither present in their neutral or fully oxidized forms nor in the radical cation of the monoruthenium [2.2] paracyclophane complex 1 with just one vinyl ruthenium moiety. These bands are thus assigned as intervalence charge-transfer (IVCT) transitions. Our results indicate that, for the radical cations, electronic coupling "through-space" via the stacked styrene decks is significantly more efficient than the "through-bond" pathway. (C) 2011 Elsevier B. V. All rights reserved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | PI-PI-STACKING; ORDER REGULAR APPROXIMATION; CENTERED MIXED-VALENCY; DENSITY-FUNCTIONAL CALCULATIONS; DISCOTIC LIQUID-CRYSTALS; CHARGE DELOCALIZATION; ELECTROLUMINESCENT PROPERTIES; MOLECULAR RECTANGLES; DELTA-E-1/2 VALUES; COMPLEXES; Vinyl complexes; Ruthenium; Cyclophanes; Electrochemistry; Spectroelectrochemistry; Mixed-valent |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Anorganische Chemie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 29 May 2020 10:49 |
| Last Modified: | 29 May 2020 10:49 |
| URI: | https://pred.uni-regensburg.de/id/eprint/20149 |
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