Kaur Irvinder, Jia Wenling, Kopreski Ryan P, Selvarasah Selvapraba, Dokmeci Mehmet R, Pramanik Chandrani, McGruer Nicol E, Miller Glen P
Department of Chemistry and Materials Science Program, University of New Hampshire, Durham, New Hampshire 03824-3598, USA.
J Am Chem Soc. 2008 Dec 3;130(48):16274-86. doi: 10.1021/ja804515y.
A combined experimental and computational study of a series of substituted pentacenes including halogenated, phenylated, silylethynylated and thiolated derivatives is presented. Experimental studies include the synthesis and characterization of six new and six known pentacene derivatives and a kinetic study of each derivative under identical photooxidative conditions. Structures, HOMO-LUMO energies and associated gaps were calculated at the B3LYP/6-311+G**//PM3 level while optical and electrochemical HOMO-LUMO gaps were measured experimentally. The combined results provide for the first time a quantitative assessment of HOMO-LUMO gaps and photooxidative resistances for a large series of pentacene derivatives as a function of substituents. The persistence of each pentacene derivative is impacted by a combination of steric resistance and electronic effects as well as the positional location of each substituent. Silylethynyl-substituted pentacenes like TIPS-pentacene possess small HOMO-LUMO gaps but are not the longest lived species under photooxidative conditions, contrary to popular perception. A pentacene derivative with both chlorine substituents in the 2,3,9,10 positions and o-alkylphenyl substituents in the 6,13 positions is longer lived than TIPS-pentacene. Of all the derivatives studied, alkylthio- and arylthio-substituted pentacenes are most resistant to photooxidation, possess relatively small HOMO-LUMO gaps and are highly soluble in a variety of organic solvents. These results have broad implications for the field of organic molecular electronics where OFET, OLED, and other applications can benefit from highly persistent, solution processable pentacene derivatives.
本文介绍了一系列取代并五苯的实验与计算相结合的研究，这些取代并五苯包括卤代、苯基化、硅乙炔基化和硫醇化衍生物。实验研究包括六种新的和六种已知并五苯衍生物的合成与表征，以及在相同光氧化条件下对每种衍生物的动力学研究。在B3LYP/6-311+G**//PM3水平上计算结构、HOMO-LUMO能量和相关能隙，同时通过实验测量光学和电化学HOMO-LUMO能隙。综合结果首次对大量并五苯衍生物的HOMO-LUMO能隙和光氧化抗性作为取代基的函数进行了定量评估。每种并五苯衍生物的持久性受到空间位阻和电子效应以及每个取代基位置的综合影响。像TIPS-并五苯这样的硅乙炔基取代并五苯具有较小的HOMO-LUMO能隙，但在光氧化条件下并不是寿命最长的物种，这与普遍看法相反。在2,3,9,10位带有氯取代基且在6,13位带有邻烷基苯基取代基的并五苯衍生物比TIPS-并五苯寿命更长。在所有研究的衍生物中，烷硫基和芳硫基取代的并五苯对光氧化最具抗性，具有相对较小的HOMO-LUMO能隙，并且在多种有机溶剂中高度可溶。这些结果对有机分子电子学领域具有广泛影响，其中有机场效应晶体管（OFET）、有机发光二极管（OLED）和其他应用可以从高度持久、可溶液加工的并五苯衍生物中受益。
