Recent Progress in Using Pyrene‐4,5‐diketones and Pyrene‐4,5,9,10‐tetraketones as Building Blocks to Construct Large Acenes and Heteroacenes

Abstract

Acenes, usually defined as segments of “graphene”, consist of linearly annulated benzene rings, and have attracted considerable interest in both theoretical research and practical applications. However, these compounds generally have undesirable features such as poor solubility, easy oxidation and photodimerization. Thus, scientists have to invest much effort to address these problems and experimentally achieve the desired electronic properties to meet various demands. Herein, we summarize recent progress in the synthesis of pyrene‐functionalized acenes and heteroacenes through the use of pyrene diketone and pyrene tetraketone building blocks. Moreover, the physical properties and applications of these semiconductors in organic semiconductor devices are also described.

11,16‐Di‐tert‐butyl‐9,18‐diphenylbenzo[kl]benzo[8,9]triphenyleno [2,3‐b]xanthene: Synthesis, Photophysics, Self‐Assembly and Electroluminescent Properties

“…Molecule BTX (CCDC number, 1884675) adopts a monoclinic crystal system, space group P2(1)/c, and the unit cell parameter of a=10.8579(11) Å, b=32.241(3) Å, c=11.3722(10) Å, β=99.542(2)° (Table S1). As shown in Figure a, the strong steric hindrance between benzo units on pyrene and the lateral phenyl groups made compound BTX form a twisted structure with the dihedral angle of 37.9° at plane C1‐C2‐C4 and plane C16‐C17‐C24, which could compare with the reported results . Figure b shows the packing model.…”

“…Recently, much attention has been paid to twistacene and analogues that defined by Wudl, in which the twisted angle is at least 30° ,. Profiting from rigid structure, high quantum yield, good thermal and photostability, the end‐capping acenes with pyrene units could be chosen as fascinating candidates for electroluminescent devices and nonlinear optics . Nonetheless, large linear acenes (>6 repeating benzo units) usually encounter some detracting features such as multistep synthesis, tedious separation and instability.…”

Electron‐Rich Twistacene‐Modified Arylboron Donor–Acceptor Systems: Synthesis, Photophysics, and Electroluminescence with Hot Exciton Response

“…Since Pascal and Wudl described the term “twistacene” containing phenanthrene or pyrene units at the terminal, a family of twistacenes has been prepared and chosen as active layers for organic electronics and biosensors because of the intriguingly high fluorescence quantum yield and stability of the twistacenes . For example, Zhang and co‐workers developed a “green and clean” Diels–Alder route to construct symmetrical and unsymmetrical end‐capping twistacenes with pyrene units, which exhibited promising electroluminescent behavior .…”

“…Since Pascal [15][16][17] and Wudl [18,19] described the term" twistacene" containing phenanthrene or pyrene units at the terminal, af amily of twistacenes has been prepareda nd chosen as activel ayers for organic electronics and biosensors because of the intriguingly high fluorescence quantum yield and stability of the twistacenes. [20][21][22][23][24][25] For example, Zhang and co-workers developed a" green and clean" Diels-Alder route to constructs ymmetrical and unsymmetrical end-capping twistacenesw ith pyrene units, which exhibited promising electroluminescent behavior. [26][27][28][29][30] Subsequently,X iao et al also synthesized al ibrary of twistacene-modified dendrimers, which selfassembled into multi-color nanoparticles for imaging specific location in living cells.…”

Crystalline Diradical Dianions of Pyrene‐Fused Azaacenes

“…respect, it is highly desirable to explore novel azaacene motifs with diradical character. Given the fact that a variety of diradicals have been isolated by expanding the p-conjugation featuring two unpaired electrons, [7] in combination with our previous work, [7k,l] we envisaged that the extension of a 6pelectron system over the central phenyl ring in II 2À and III 2À to a cross-conjugated pyrene unit should greatly increase the conjugation both in transverse and longitudinal directions, [8] which may generate the unprecedented diradical dianions of azaacenes (V 2À CC, Scheme 1 d). Herein, we report the isolation of novel pyrene-fused azaacene diradical dianions 1 2À CC and 2 2À CC with diradical character (Scheme 2).…”