Introducing N atoms to the pentacene backbone leads to N‐heteropentacenes, whose properties can be tuned by changing the number, position and valence state of N atoms in the pentacene backbone. With ...a rapid development in recent years, N‐heteropentacenes and their derivatives have arisen as a new family of organic semiconductors with high performance in organic thin‐film transistors (OTFTs). This article reviews the research efforts of developing N‐heteropentacenes into organic semiconductors starting from 2003 with emphasis on the work of the author's group since 2009. The structure–property relationship and design rationale are highlighted based on an overview of reported organic semiconductors of N‐heteropentacenes.
With a rapid development, N‐heteropentacenes and their derivatives have recently arisen as a new family of organic semiconductors with high performance in organic thin‐film transistors. This Research News provides an overview of the efforts to develop N‐heteropentacenes into organic semiconductors starting from 2003, with emphasis on the work of the author's group since 2009, highlighting structure–property relationships and design rationale.
The past decade has witnessed remarkable success in the synthesis of curved polycyclic aromatics through Scholl reactions which enable oxidative aryl–aryl coupling even in company with the ...introduction of significant steric strain. These curved polycyclic aromatics are not only unique objects of structural organic chemistry in relation to the nature of aromaticity but also play an important role in bottom-up approaches to precise synthesis of nanocarbons of unique topology. Moreover, they have received considerable attention in the fields of supramolecular chemistry and organic functional materials because of their interesting properties and promising applications. Despite the great success of Scholl reactions in synthesis of curved polycyclic aromatics, the outcome of a newly designed substrate in the Scholl reaction still cannot be predicted in a generic and precise manner largely due to limited understanding on the reaction mechanism and possible rearrangement processes. This review provides an overview of Scholl reactions with a focus on their applications in synthesis of curved polycyclic aromatics with interesting structures and properties and aims to shed light on the key factors that affect Scholl reactions in synthesizing sterically strained polycyclic aromatics.
Replacement of the allylic C=C−C unit with a N−B−N unit at each of the three zigzag edges of 4triangulene gives rise to B3N6‐4triangulene, which is envisioned to represent a key structural unit of a ...new hypothetical boron carbon nitride (BC4N). A tert‐butylated B3N6‐4triangulene has been successfully synthesized by three‐fold nitrogen‐directed borylation, and the X‐ray crystallographic analysis indicates that its slightly bent triangular polycyclic framework can be viewed as a 1,3,5‐triphenylbenzene connected by three 4π‐electron N−B−N units. The HN−B−NH moiety provides a dual hydrogen‐bond donor, which forms H‐bonds with halide or carboxylate anions in solution, and form DD‐AA hydrogen‐bond arrays with 2,7‐di(tert‐butyl)‐pyrene‐4,5,9,10‐tetraone in the co‐crystal. Moreover, the blue fluorescence of B3N6‐4triangulene in solution is responsive to binding p‐nitrobenzoate anion through hydrogen bonds.
B3N6‐4triangulene, which is isoelectronic to the trianion of 4triangulene, represents a key structural unit of a new hypothetical boron carbon nitride. The tert‐butylated derivative of B3N6‐4triangulene is synthesized by threefold nitrogen‐directed borylation. Its fluorescence in solution is responsive to binding p‐nitrobenzoate anion through H‐bonds, and it forms DD‐AA H‐bond arrays with di(tert‐butyl)‐pyrenetetraone in the co‐crystal.
Recent findings on the skeletal rearrangement of polycyclic aromatics under oxidative and acidic conditions are envisioned to help development of these Scholl reactions into a more useful and ...versatile method for synthesizing polycyclic aromatics on the basis of rational design rather than luck.
Conjugated nanobelts are attractive molecules of esthetic appeal, synthetic challenges, unique properties, interesting applications, and potential impacts. The recent years have witnessed significant ...progress in the synthesis of carbon nanobelts and approaches to a new type of conjugated nanobelts. This review emphasizes two general synthetic strategies to approach conjugated nanobelts, and briefly covers structurally related nanobelts that are not fully conjugated, and finally provides an outlook for new directions in the field.
The recent years have witnessed significant progress in the synthesis of conjugated nanobelts, which are attractive molecules of aesthetic appeal, synthetic challenges, unique properties, interesting applications and potential impacts. This review covers two types of conjugated nanobelts with emphasis on two general synthetic strategies, and briefly introduces structurally related nanobelts that are not fully conjugated, and finally provides an outlook for new directions in the field.
This study tracked the long‐term effect of perceptual individuation training on reducing 5‐year‐old Chinese children's (N = 95, Mage = 5.64 years) implicit pro‐Asian/anti‐Black racial bias. Initial ...training to individuate other‐race Black faces, followed by supplementary training occurring 1 week later, resulted in a long‐term reduction of pro‐Asian/anti‐Black bias (70 days). In contrast, training Chinese children to recognize White or Asian faces had no effect on pro‐Asian/anti‐Black bias. Theoretically, the finding that individuation training can have a long‐term effect on reducing implicit racial bias in preschoolers suggests that a developmentally early causal linkage between perceptual and social processing of faces is not a transitory phenomenon. Practically, the data point to an effective intervention method for reducing implicit racism in young children.
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•Insights into two key factors for designing n-type organic semiconductors.•A survey of high-mobility n-type organic semiconductors.•Recent progress of n-channel organic thin film ...transistors.
This digest aims to provide organic chemists with an overview of recent progress on n-type organic semiconductors for application in organic thin film transistors (OTFTs) with an emphasis on molecular design. Herein, we survey n-type organic semiconductors with field effect mobility of 1cm2/Vs or higher in OTFTs after a brief introduction to the structure and operation of OTFTs and discussion of two key factors (frontier molecular orbitals and molecular packing) of organic semiconductors. On the basis of this survey, we finally reach conclusions on the current status of n-type organic semiconductors for OTFTs and provide an outlook for molecular design.
Zigzag carbon nanobelts are a long‐sought‐after target for organic synthesis. Herein we report new strategies for designing and synthesizing unprecedented zigzag carbon nanobelts, which present a ...wave‐like arrangement of hexagons in the unrolled lattice of (n,0) single wall carbon nanotubes (n=16 or 24). The precursors of these zigzag carbon nanobelts are hybrid cyclic arylene oligomers consisting of meta‐phenylene and 2,6‐naphthalenylene as well as para‐phenylene units. The Scholl reactions of these cyclic arylene oligomers form multiple carbon‐carbon bonds selectively at the α‐positions of naphthalene units resulting in the corresponding zigzag carbon nanobelts. As monitored with fluorescence spectroscopy, one of these nanobelts binds C60 with an association constant as high as (6.6±1.1)×106 M−1 in the solution in toluene. Computational studies combining linear regression analysis and hypothetical homodesmotic reactions reveal that these zigzag nanobelts have strain in the range of 67.5 to 69.6 kcal mol−1, and the ladderization step through Scholl reactions is accompanied by increase of strain as large as 69.6 kcal mol−1. The successful synthesis of these nanobelts demonstrates the powerfulness and efficiency of Scholl reactions in synthesizing strained polycyclic aromatics.
Regioselective Scholl reactions have enabled successful synthesis of unprecedented zigzag carbon nanobelts, which present a wave‐like arrangement of hexagons in the unrolled lattice of (n,0) single wall carbon nanotubes (n=16 or 24). As monitored with fluorescence spectroscopy, one of these nanobelts binds C60 with an association constant as high as (6.6±1.1)×106 M−1 in toluene.
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