Mono- and Dicarbonyl-Bridged Tricyclic Heterocyclic Acceptors: Synthesis and Electronic Properties

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• 作者：Yulia A. Getmanenko ; Chad Risko ; Paul Tongwa ; Eung-Gun Kim ; Hong Li ; Bhupinder Sandhu ; Tatiana Timofeeva ; Jean-Luc Bre虂das ; Seth R. Marder
• 刊名：Journal of Organic Chemistry
• 出版年：2011
• 出版时间：April 15, 2011
• 年：2011
• 卷：76
• 期：8
• 页码：2660-2671
• 全文大小：1173K
• 年卷期：v.76,no.8(April 15, 2011)
• ISSN：1520-6904

文摘

A series of trialkylsilyl-substituted 2,2鈥?dithiophene, 4,4鈥?di-n-hexyl-2,2鈥?dithiophene, 5,5鈥?dithiazole, and 2,2鈥?diselenophene with carbonyl (2a鈭?b>d) and 伪-dicarbonyl bridges (3a鈭?b>d) were prepared from readily available dihalides, using double lithiation followed by trapping with N,N-dimethylcarbamoyl chloride or diethyl oxalate (or N,N-dimethylpiperazine-2,3-dione), respectively. Cyclic voltammetry reveals that the first half-wave reduction potentials for this series of compounds span a wide range, from 鈭?.87 to 鈭?.97 V vs the ferrocene/ferrocenium couple at 0 V (0.1 M ⁿBu₄NPF₆ in THF). A significant increase of the first half-wave reduction potential (by 0.50鈭?.67 V) was observed on substitution of the monocarbonyl bridge with 伪-dicarbonyl. Adiabatic electron affinity (AEA, gas phase) trends determined via density functional theory (DFT) calculations are in good agreement with the electrochemical reduction potentials. UV鈭抳is absorption spectra across the series show a weak absorption band in the visible range, corresponding to the HOMO鈫扡UMO transition within a one-electron picture, followed by a more intense, high-energy transition(s). Single-crystal X-ray structural analyses reveal molecular packing features that balance the interplay of the presence of the bulky substituents, intermolecular 蟺-stacking interactions, and S路路路O intermolecular contacts, all of which affect the DFT-evaluated intermolecular electronic couplings and effective charge-carrier masses for the crystals of the tricyclic cores.