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rdf:type
lifeskim:mentions
pubmed:issue
26
pubmed:dateCreated
2011-6-10
pubmed:abstractText
A series of dicyanobiphenylcyclophanes 1-6 with various ?-backbone conformations and characteristic n-type semiconductor properties is presented. Their synthesis, optical, structural, electrochemical, spectroelectrochemical, and packing properties are investigated. The X-ray crystal structures of all n-type rods allow the systematic correlation of structural features with physical properties. In addition, the results are supported by quantum mechanical calculations based on density functional theory. A two-step reduction process is observed for all n-type rods, in which the first step is reversible. The potential gap between the reduction processes depends linearly on the cos(2) value of the torsion angle ? between the ?-systems. Similarly, optical absorption spectroscopy shows that the vertical excitation energy of the conjugation band correlates with the cos(2) value of the torsion angle ?. These correlations demonstrate that the fixed intramolecular torsion angle ? is the dominant factor determining the extent of electron delocalization in these model compounds, and that the angle ? measured in the solid-state structure is a good proxy for the molecular conformation in solution. Spectroelectrochemical investigations demonstrate that conformational rigidity is maintained even in the radical anion form. In particular, the absorption bands corresponding to the SOMO-LUMO+i transitions are shifted bathochromically, whereas the absorption bands corresponding to the HOMO-SOMO transition are shifted hypsochromically with increasing torsion angle ?.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Jun
pubmed:issn
1521-3765
pubmed:author
pubmed:copyrightInfo
Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
pubmed:issnType
Electronic
pubmed:day
20
pubmed:volume
17
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7236-50
pubmed:year
2011
pubmed:articleTitle
Conformationally controlled electron delocalization in n-type rods: synthesis, structure, and optical, electrochemical, and spectroelectrochemical properties of dicyanocyclophanes.
pubmed:affiliation
Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland.
pubmed:publicationType
Journal Article