The structures of molecular compounds exhibiting polarization bonding. II. The crystal structure of the chloranil–hexamethylbenzene complex
01 Dec 1955-Acta Crystallographica (International Union of Crystallography)-Vol. 8, Iss: 12, pp 787-794
About: This article is published in Acta Crystallographica.The article was published on 1955-12-01. It has received 36 citations till now. The article focuses on the topics: Chloranil & Hexamethylbenzene.
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TL;DR: In this paper, a charge-transfer origin (λCT) analysis of the colored solutions revealed their charge transfer origin and provided quantitative information of the intermolecular association in the form of the KDA and eCT values for the formation and visualization, respectively, of different [D,A] complexes.
Abstract: Molecular association of various aromatic hydrocarbons (D, including sterically hindered donors) with a representative group of diverse acceptors (A = quinone, trinitrobenzene, tetracyanoethylene, tropylium, tetranitromethane, and nitrosonium) is visually apparent in solution by the spontaneous appearance of distinctive colors. Spectral (UV−vis) analyses of the colored solutions reveal their charge-transfer origin (λCT), and they provide quantitative information of the intermolecular association in the form of the KDA and eCT values for the formation and visualization, respectively, of different [D,A] complexes. Importantly, such measurements establish charge-transfer absorption to be a sensitive analytical tool for evaluating the steric inhibition of donor−acceptor association. For example, the steric differences among various hindered aromatic donors in their association with quinone are readily dramatized in their distinctive charge-transfer (color) absorptions and verified by X-ray crystallography of ...
259 citations
TL;DR: The findings provide information used to explain fluorescence intensity values at lambda(em) at 530 nm from studies that combine AO, caffeine, and dsDNA.
136 citations
TL;DR: Sodann et al. as mentioned in this paper discuss the zwischenmolekulare Bindung durch intermole kulare Mesomerie in Elektronen-Donator-Acceptor-Komplexen.
Abstract: Von den energetischen Voraussetzungen einer Ionenbildung durch direkten Elektronenubergang von einem organischen Elektronendonator-Molekul D auf ein organisches Elektronenacceptor-Molekul A ausgehend, wird die zwischenmolekulare Bindung durch intermolekulare Mesomerie in Elektronen-Donator-Acceptor-Komplexen (EDA-Komplexen) erlautert Sodann werden die Elektronen-Absorptionsspektren und die Emissions-(Fluoreszenz- und Phosphoreszenz-)Spektren von Elektronen-Donator-Acceptor-Komplexen an Hand vorwiegend eigener experimenteller Untersuchungen der letzten Jahre im Zusammenhang besprochen und theoretisch erklart Dabei werden Zusammenhange zwischen dem optischen Verhalten und den energetischen Zustandsgrosen der Elektronen-Donator-Acceptor-Komplexe und der Ionisierungsenergie bzw der Elektronenaffinitat der D- und A-Komponente diskutiert
135 citations
TL;DR: In this article, the steric effects provided the quantitative basis to modulate (and differentiate) outer and inner-sphere pathways provided by matched pairs of hindered and unhindered donors with otherwise identical electron-transfer properties.
Abstract: The various aromatic hydrocarbons (Chart 2) constitute a sharply graded series of sterically encumbered (unhindered, partially hindered, and heavily hindered) donors in electron transfer (ET) to quinones (Chart 1). As such, steric effects provide the quantitative basis to modulate (and differentiate) outer-sphere and inner-sphere pathways provided by matched pairs of hindered and unhindered donors with otherwise identical electron-transfer properties. Thus the hindered donors are characterized by (a) bimolecular rate constants (k2) that are temperature dependent and well correlated by Marcus theory, (b) no evidence for the formation of (discrete) encounter complexes, (c) high dependency on solvent polarity, and (d) enhanced sensitivity to kinetic salt effectsall diagnostic of outer-sphere electron-transfer mechanisms. Contrastingly, the analogous unhindered donors are characterized by (a) temperature-independent rate constants (k2) that are 102 times faster and rather poorly correlated by Marcus theory, (...
117 citations