Fused Pyrazine‐ and Carbazole‐Containing Azaacenes: Synthesis and Properties

Abstract

A new family of azaacenes has been designed and synthesized by incorporating the electron‐withdrawing sp2‐hybridized nitrogen of pyrazine and electron‐donating nitrogen of carbazole in a molecular skeleton. Two different conjugated lengths of 8‐ring aza‐nonacene and 10‐ring aza‐undecene have been achieved by an efficient condensation reaction. The unique optoelectronic properties of these molecules were investigated using both experimental and theoretical techniques. The azaacenes show visible‐region absorption and near‐infrared (NIR) fluorescence. These compounds can serve as hole‐transport semiconductors for solution‐processed organic field‐effect transistors (OFETs). Single‐crystal transistor devices of one of the aza‐nonacenes exhibit hole charge transport behavior with a hole mobility of 0.07 cm2/Vs and an on/off current ratio of 1.3x106.

Recent progress in pyrazinacenes containing nonbenzenoid rings: synthesis, properties and applications

“…The enhanced oxidation potentials relative to TTF suggest the good electronic transporting ability between the donor and acceptor. Besides, N-containing heterocycles including carbazole, 60 imidazole, 100–102 indolizine, 103 etc. 65,68,104–106 are more popular decorating units for azaacenes.…”

“…65,68,104–106 are more popular decorating units for azaacenes. For example, Liao et al 60 synthesized a series of stable and soluble carbazole-containing azaacenes ( 65a-c ) via sample condensation reactions. The carbazole rings acted as donors while two pyrazine units were acceptors in one molecular skeleton.…”

Azaacenes Based Electroactive Materials: Preparation, Structure, Electrochemistry, Spectroscopy and Applications—A Critical Review

“…Some ambipolar azaacenes are depicted in Table 12 ( 79 [ 108 ], 78 [ 109 ]). Azaacenes exhibiting only p-type electrical transport and for these reasons used in p-channel FETs were also reported ( 86 in Table 12 ) [ 110 ]. In Table 12 (positions 75 – 88 ) chemical formulae of selected azaacenes are shown tested as components of active layers in field effect transistors together with their charge carriers mobilities measured in the FET configuration.…”

Towards the Bisbenzothienocarbazole Core: A Route of Sulfurated Carbazole Derivatives with Assorted Optoelectronic Properties and Applications

“…The inclusion of heterocycles into the pentacene backbone has been a frequently exploited strategy in the search for novel materials with enhanced stability and performance. Notably, many derivatives containing or combining thiophene, pyrrole or even more extended cores such as [1]benzothieno [3,2-b] [1]benzothiophene (BTBT) have achieved this goal [15][16][17][18][19][20]. Carbazole as a synthetic building block also represents an important source of organic molecules with assorted applications within the optoelectronic field.…”

“…Carbazole as a synthetic building block also represents an important source of organic molecules with assorted applications within the optoelectronic field. In fact, it does not only stand as a promising scaffold for new organic semiconductors, but also displays outstanding photophysical properties [9,[20][21][22][23][24].…”