Anorganisch-Chemisches Institut, Universität Heidelberg , Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
Max Planck Institute for Solid State Research , Heisenbergstr.1, 70569 Stuttgart, Germany.
J Org Chem. 2017 Dec 1;82(23):12492-12502. doi: 10.1021/acs.joc.7b02286. Epub 2017 Nov 20.
Tetraazaperopyrenes (TAPPs) have been functionalized with thiophene and terthiophene units of different architecture resulting in a variety of organic donor-acceptor (D-A) compounds. The influence of the connection of the thiophenes to the TAPP core on their structural, photophysical and electrochemical properties has been studied in detail by a combination of X-ray crystallography, UV-vis and fluorescence spectroscopy as well as cyclic voltammetry, which allowed the establishment of structure-property relationships. The HOMO-LUMO gap is significantly decreased upon substitution of the TAPP core with electron-donating thiophene units, the extent of which is strongly influenced by the orientation of the thiophene units. The latter also crucially directs the molecular packing in the solid. Linkage at the α-position allows both inter- and intramolecular N···S interaction, whereas linkage in the β-position prevents intramolecular N···S interaction, resulting in a less pronounced conjugation of the TAPP core and the thiophene units. The new TAPP derivatives were processed as semiconductors in organic thin-film transistors (TFTs) that show ambipolar behavior. The insight into band gap and structure engineering may open up new possibilities to tailor the electronic properties of TAPP-based materials for certain desired applications.
四氮杂并五苯（TAPPs）已经被噻吩和不同结构的三噻吩单元官能化，从而产生了各种有机给体-受体（D-A）化合物。通过结合 X 射线晶体学、紫外可见和荧光光谱以及循环伏安法详细研究了噻吩与 TAPP 核心连接对其结构、光物理和电化学性质的影响，这使得建立了结构-性质关系。用给电子噻吩单元取代 TAPP 核心会显著降低 HOMO-LUMO 能隙，其程度强烈受到噻吩单元取向的影响。噻吩单元的这种取向也会极大地影响分子在固体中的堆积。在 α-位连接允许形成分子间和分子内 N···S 相互作用，而在 β-位连接则阻止了分子内 N···S 相互作用，从而导致 TAPP 核心和噻吩单元的共轭程度降低。新的 TAPP 衍生物作为半导体被加工成有机薄膜晶体管（TFTs），这些晶体管表现出双极性行为。对能带隙和结构工程的深入了解可能为基于 TAPP 的材料的电子性质调整开辟新的可能性，以满足某些特定应用的需求。
