Electron Confinement in Structurally Constrained σ-Bonded π-Systems. An Experimental and Density Functional Investigation
2000; American Chemical Society; Volume: 122; Issue: 19 Linguagem: Inglês
10.1021/ja9944148
ISSN1943-2984
AutoresAngelika Niemz, A.O. Cuello, L. Kraig Steffen, Benjamin F. Plummer, Vincent M. Rotello,
Tópico(s)Advanced NMR Techniques and Applications
ResumoWe have explored the effect of resonance overlap on electronic communication in σ-bonded π-systems through a combined experimental and computational investigation. The system studied consists of a series of diphenyl-substituted acenaphthofluoranthenes and fluoranthenes with constrained dihedral angles between polycyclic core and phenyl substituents of 90°, 70°, and 15°. The spin density distribution within the radical anions of these conformationally restricted polycyclic aromatic hydrocarbons was assessed via DFT-B3LYP calculations validated through SEEPR-derived experimental hyperfine coupling constants (hfc's). Orthogonal subsystems were essentially insulated, while substantial delocalization of spin density was observed for near-planar subsystems. The insulation of the phenyl substituents combined with the possibility of forming ladder-type polymers makes the orthogonal diphenyl-substituted acenaphthofluoranthenes intriguing building-blocks for molecular electronics.
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