一种三重对称硫杂扭曲多环芳烃的合成

硫杂多环芳烃具有并苯类物质的独特导电作用和光合作用中能够提高导电作用和光电效率的独特优势。围绕硫杂多环芳烃,以1,3,5-三(2-溴苯基)苯和苯并噻吩-2-硼酸通过钯催化的Suzuki反应得到苯并噻吩结构的寡聚苯撑分子,苯并噻吩结构的寡聚苯撑分子在FeCl_(3)作用下氧化脱氢环化合成了三重硫杂扭曲多环芳烃分子。中间体和产物的结构通过核磁共振波谱、质谱进行了表征。三硫杂多环芳烃的合成丰富了硫杂多环芳烃的种类,为合成更大共轭体系的三重硫杂扭曲多环芳烃提供了研究基础,三重硫杂扭曲多环芳烃分子为有机半导体材料,发光材料太阳能电池,光电二极管等分子器件提供的重要的候选材料。

Triple Aza[6]helicenes with Circularly Polarized Luminescence:N-Alkylation as a Tool to Tune the Chiroptical Properties

Recently,multiple helicenes have attracted enormous attention due to their exceptionally distorted conjugated architectures,appealing optical properties and unique spatial stacking patterns.The electronic and optical properties of multiple helicenes could be modulated by heteroatom doping.Herein,the first triple aza[6]helicene was reported by an intramolecular oxidation reaction,which exhibited highly distorted propeller-like geometry revealed by single crystal X-ray diffraction analysis.In comparison to the reported triple oxa[6]helicene,the triple aza[6]helicene demonstrated increased quantum yield(5.5%),and chiroptical properties with a|gabs|value of 0.012 and a|glum|value of 3.0×10^(-3).Furthermore,the stability and chiroptical properties of the triple aza[6]helicene could be enhanced by N-alkylation.

Helicene-type β-isoindigo-based boron-dipyrromethene analogs with strong near-infrared chiroptical activity

Near-infrared(NIR)chiroptical response has been less explored because it is chal-lenging to achieve both chirality and NIR absorption/emission.Herein,we describe the design of heterohelicene-typeβ-isoindigo-based boron-dipyrromethene(BOD-IPY)analogs(β-IBs),which shift the absorption peak to 800 nm and produce significant Cotton effects(127.8 M-1 cm-1)and absorbance dissymmetry factors(|gabs|3.5=×10-3).The luminescence dissymmetry factor(glum)and circu-larly polarized luminescence(CPL)brightness(BCPL)of up to 1.24×10-3 and 1.78 M-1 cm-1 were realized beyond 800 nm.Theseβ-IBs are thefirst examples of helicene-type compounds with the highest gabs in the NIR region and CPL beyond 800 nm.Theoretical calculations demonstrate that the strong chiroptical activities are triggered by their large transition magnetic dipole moments.This study not only provides a new approach to the synthesis of a larger variety of unprecedented helicene-type BODIPY analogs but also demonstrates excellent NIR chiroptical properties.

On-surface Synthesis of Multiple Non-benzenoid Carbohelicenes Fused with Fluorene Unit(s)

Comprehensive Summary Carbohelicenes have garnered considerable attention for their inherent chirality and structural flexibility.Increasing multi-helicity and incorporating non-six-membered rings to substitute benzenoid rings within helicenes are effective strategies for introducing unique photoelectric properties.Despite the disclosure of numerous helicenes,the inaccessible precursors and the lack of synthetic routes pose a challenge in achieving desired helicene structures fused with non-benzenoid rings.Herein,we report the synthesis of multiple non-benzenoid carbohelicenes fused with fluorene unit(s)through intramolecular cyclodehydrogenation of 9,10-di(naphthalen-1-yl)anthracene on Au(111)surface.Two potential cyclodehydrogenation manners between naphthyl and anthracene lead to the formation of fluorene-fused[5]helicene and[4]helicene moiety.Consequently,a total of four stable products were observed.The atomic topographies of products are characterized by bond-resolving scanning tunneling microscopy.The chiral helicity of targeted products can be switched by tip manipulation.Density-functional-theory calculations unveils the reaction pathway of four products.The comparative analysis of their respective energy barriers exhibits a correlation with the experimentally determined yields.Furthermore,we synthesize the polymer chains incorporating non-benzenoid carbohelicenes via the Ullmann reaction of 2,6-dibromo-9,10-di(1-naphthyl)anthracene precursors.Our work proposes a synthetic methodology for several novel helicene-like structures fused with fluorene units and the polymer bearing helicene subunits,thus highlighting the immense potential of these compounds in the application fields of luminescent electronic devices.

Synthesis,Structures,and Chiroptical Properties of NBN-Doped Helicenes with Boron Atoms in the Inner Rims

The precise synthesis of helicenes with topologically defined length and specific heteroatomic perturbation in the screw-like conjugated skeletons plays an emerging role in the manipulation of chiral materials.Facile,selective,and programmable routes to helicenes or heterohelicenes are highly desirable yet challenging for structure-chiroptical property relationship studies.Herein,we report the synthesis and characterization of NBN-doped helicenes with boron atoms in the inner rims,enabled by the highly regioselective one-pot borylation of rationally designed precursors with,namely,fold-in or pan-out manner.The incorporation of nonbonded boron and nitrogen atoms resulted in narrow-band emission and improved optical properties for the single-stranded carbon helix.In addition,numbers and arrangement modes of fused six-membered rings have distinct effects on configurational stability and chiroptical properties,revealing that BN-[6]H with strong circular dichroism is a promising candidate for chiral sensors.The combination of experimental and theoretical studies on these helical structures might provide insights into the design of helically chiral small-molecule-based sensors or emitters.

Quadruple[6]Helicene Featuring Pyrene Core:Unraveling Contorted Aromatic Core with Larger Effective Conjugation

Multiple helicenes display distinct aromatic cores characterized by highly twisted rings that are shared or fused with constituent helicene moieties.Diversifying these aromatic cores unlocks avenues for creating multiple helicenes with distinct properties and topologies.Herein we report the synthesis of a quadruple[6]helicene featuring pyrene as the aromatic core.The synthesis involved key steps of the annulativeπ-extension reaction and Scholl reaction.By extending multiple helicenes along the axial direction,the degree of contortion of the aromatic core can be controlled from nearly flat to highly twisted.Notably,quadruple[6]-helicene exhibits a significant red-shift of 0.49 eV compared to quadruple[4]-helicenes,of which the red-shift arises from bothπ-extension and augmented effective conjugation due to enhanced twisting.Quantum chemical calculations demonstrate that the degree of contortion in the pyrene core adeptly governs the energy levels of the HOMO and LUMO,which offers an alternative strategy beyond mere enlargement of theπbackbone.An intriguing serendipitous finding reveals the formation of one-molecule-thick supramolecular homochiral nanosheets through selfinterlocking interactions of enantiomers in single crystals,a rare packing motif for multiple helicenes.

Enantioselective Synthesis,(Chir)optical Properties,and Postsynthetic Functionalization of Furan-Containing Oxa[5]-,Oxa[6]-,and Dioxa[6]helicenes

An expedient synthesis of a series of configurationally stable oxa[5]helicenes,oxa[6]helicenes,and dioxa[6]helicenes has been developed using an intramolecular,highly enantioselective,Au-catalyzed,alkyne hydroarylation reaction.The absolute configuration of the newly prepared structures has been established by crystallography,their inversion barriers have been determined theoretically and experimentally,and their chiroptical properties have been investigated.Comparison of these data with those reported for thia-or carbohelicenes sharing an otherwise identical helical framework enables the establishment of comprehensive correlations between the nature of the embedded(hetero)atom(s)and the magnitude of these properties.Preliminary studies on the postsynthetic functionalization of the oxahelicenes obtained are also described.Specifically,siteselective bromination at the 15-position in oxa[5]helicene 5d allows its subsequent manipulation into pyridine-containing aza-oxa[7]helicene 13d;while the two termini of oxa[6]helicene 7d have been intramolecularly cyclised into the pleiadeno[1,12,11-bcde]benzofuran derivative 15d by acidic treatment.Both transformations take place without erosion of the enantiopurity.

基于AB型单体聚醚酰亚胺共聚物的合成与性能

将AB型单体3-氨基-5,6,9,10-四氢-[5]螺旋烯-7,8-二羰基-二甲酸酐(ATHDA)与4,4’-(4,4’-异亚丙基二苯氧基)双(邻苯二甲酸酐)(BPADA)和4,4’-二氨基二苯醚(ODA)通过高温一步法共聚,制备了一系列ATHDA含量不同的聚醚酰亚胺PEI-AB_(x)(x为ATHDA用量,以BPADA和ODA的总质量计,下同)。采用FTIR、~1HNMR、DSC、DMA、TGA对聚合物进行了表征,对其力学性能和溶解性进行了测试。结果表明,PEI-AB_(x)特性黏数在0.60~0.87 dL/g之间,均具有良好的成膜性,且该系列聚合物在常见的有机溶剂N,N-二甲基乙酰胺、N-甲基吡咯烷酮中均具有优异的溶解性;由DMA测得的玻璃化转变温度(T_(g))在228~256℃之间,N_(2)气氛下5%热失重温度(T_(5%))为505~536℃,表明PEI-AB_(x)具有优异的热稳定性;聚合物薄膜的拉伸强度、杨氏模量和断裂伸长率分别在41.7~88.1 MPa、1.7~2.7 GPa和3.3%~4.8%之间,具有良好的力学性能。另外,聚合物分子链中的四氢-[5]螺旋烯结构可脱氢芳构化,与PEI-AB_(20)相比,芳构化后PEI-AB_(20)的T_(g)从256℃提高至283℃,T_(5%)从531℃提升至557℃,表明芳构化后聚合物耐热性得到进一步提升。

具有极小能量的全角六角链

共轭分子的总π-电子能量可以通过它的分子图来计算.对于一般的六角链,一些重要类型的共轭分子的极值问题已得到解决.全角六角链的最大特征值的极值问题也已清楚.给出了n个六边形的全角六角链的极小能量图.

螺烯制备方法的研究进展

综述了螺烯的制备方法方面的进展,述及的螺烯制备方法包括光化学反应、Diels-Alder反应、成烯关环反应以及过渡金属催化三炔的[2+2+2]环化异构化反应等.此外,文中还对螺烯的手性拆分方法进行了论述,并对双螺烯的制备设计予以展望.

基于螺烯的新型手性有机分子笼

有机分子笼是一类具有独特内在空腔的三维有机分子,在分子识别与分离、催化反应、气体吸附与存储等领域有着广阔的应用前景。有机分子笼的性能主要取决于骨架分子的化学结构与键合方式,而目前成功用于合成有机分子笼的前驱分子种类还比较有限,尤其是手性分子笼。近来,上海交通大学邱惠斌课题组以具有本征螺旋共轭结构的螺烯作为骨架分子,通过动态共价键等可逆键合过程,构建了一系列具有手性超级结构的有机分子笼,在手性识别与分离、圆偏振发光、手性分子开关等应用领域进行了积极探索。

噻吩螺烯的化学与光化学合成

本文综述了近年来噻吩螺烯的化学与光化学合成方面的重要进展。在螺烯的化学合成方面,阐明了单螺烯的常见合成手法,即以并三噻吩为构筑模块,合成螺烯前驱体联并三噻吩,其后通过硫代关环手法制备噻吩单螺烯。由于前驱体的两个并噻吩片段可能存在分子内的相互作用,造成无法无限制增长螺烯分子的尺寸。通过增加助溶基团的合成策略可以将螺烯的分子结构由单螺烯引入到双螺烯。在螺烯的光化学合成方面,光化学氧化关环的实例表明了光化学是构筑单螺烯与双螺烯的有效手法。由于存在前驱体双键在光照条件下可以打开产生双自由基的光化学反应机理,在其后关环步骤可有效产生外消旋体与内消旋体这样有趣的双螺烯产物。此外,本文针对噻吩螺烯领域的前景,提出了3个方面的观点:1)通过设计末端噻吩环上硫原子的位置异构,形成新的螺烯同分异构体;2)通过合成设计,可以制备新结构的双螺烯与多螺烯;3)通过手性拆分,可将螺烯旋光体应用于手性催化、手性组装等应用领域。

活性中间体2,12-二甲氧基-7-氧代-[5]-螺旋烯的合成

7-氧代-[5]-螺旋烯是一种重要的活性中间体,它在材料与催化科学、医药和有机光电等方面都有重要应用.本文以2,7-二羟基萘为原料,经过氧化偶联、醚化、酸催化环化等反应,从克级小试开始摸索反应条件和后处理纯化方法,不断进行工艺优化和放大到百克级合成目标产物,并通过LCMS以及^(1)H NMR对所有中间体和产物进行结构鉴定.

A C2-symmetric triple [5]helicene based on N-annulated triperylene hexaimide for chiroptical electronics

Two diastereoisomers(NTPH-P and NTPH-T1) as a C2-symmetric triple [5]helicene based on N-annulated triperylene hexaimide were synthesized.Aided by nuclear magnetic resonance spectroscopy(NMR) and theoretical calculations,NTPH-P was assigned to three-blade propeller conformation while NTPH-T1 tended to exhibit twisted conformation with pyrrole ring fusing on a bowl-shaped PDI foil.Characterized by circular dichroism(CD) and circular polarized luminescence(CPL) measurements,the enantiomerically pure NTPH-P exhibited fairly good chiral activities both in the absorption and emission range with dissymmetry factors |gabs| of 4.1×10^-3 and |glum| of 1.2×10^-3.The diastereoisomers were further employed as acceptors for organic solar cells with distinct PCEs of 8.11% and 5.24% for NTPH-P and NTPH-T1 based devices,respectively,signifying the prospects in chiroptical electronics by designing molecularly defined aromatics.

Thermally activated delayed fluorescence materialsensitized helicene enantiomer-based OLEDs:a new strategy for improving the efficiency of circularly polarized electroluminescence

A new strategy of thermally activated delayed fluorescence(TADF)material-sensitized circularly polarized luminescence(CPL)has been proposed for improving the efficiencies of fluorescent circularly polarized organic lightemitting diodes(OLEDs)(CP-OLEDs).Consequently,a pair of helicene enantiomers,(P)-HAI and(M)-HAI,were synthesized.The helicene enantiomers with the rigid helicalπ-skeleton had highly thermal and enantiomeric stabilities,and they also showed excellent photophysical properties,especially,intense mirror-image CPL activities with large luminescence dissymmetry factor(|g_(lum)|)values of about 6×10^(-3).Notably,the CP-OLEDs with the helicene enantiomers as emitters and a TADF molecule as sensitizer not only displayed better performance of lower turn-on voltage(V_(T))of 2.6 V,four-fold maxmium-external quantum efficiency(EQE_(max))of 5.3%,and lower efficiencies roll-off of 1.9%at 1000 cd m^(-2),than those of the devices without TADF sensitizer,but also exhibited intense circularly polarized electroluminescence(CPEL)with the electroluminescence dissymmetry factor(g_(EL))values of-2.3×10^(-3)and+3.0×10^(-3).Meanwhile,this study also represents the first thermally activated sensitized fluorescent CP-OLEDs with markedly enhanced efficiencies and intense CPEL.

Synthesis, two-photon absorption and AIE properties of multibranched thiophene-based triphenylamine derivatives with triazine core

Two new multibranched thiophene-based triarylamine derivatives with 1,3,5-triazine core are synthesized and characterized. Their one-and two-photon absorption properties and aggregation-induced emission effect have been investigated. Both the STAPA-based compounds are AIE active. The two-photon absorption (2PA) cross sections measured by the open aperture Z-scan technique are determined to be 620 and 1610 GM for STAPA-a and STAPA-b in chloroform,respectively, which dramatically increase with the introduction of alkyl chains. The relationship between their structures and properties on one-and two-photon absorption and aggregation-induced emission is discussed, which allows us to examine the effect of introducing alkyl chains. In addition, solvent effects also show a significant influence on the 2PA cross section. The two compounds with excellent AIE and 2PA properties provide attractive alternatives for the biophotonic materials.

Thiophene-based covalent organic frameworks for highly efficient iodine capture

Development of adsorbent materials for highly efficient iodine capture is high demand from the perspective of ecological environment and human health. Herein, the two kinds of thiophene-based covalent organic frameworks(COFs) with different morphologies were synthesized by solvothermal reaction using thieno[3,2-b]thiophene-2,5-dicarbaldehyde(TT) as the aldehyde monomer and tri(4-aminophenyl)benzene(PB) or tris(4-aminophenyl)amine(PA) as the amino monomer(denoted as PB-TT COF and PA-TT COF) and the as-prepared two heteroatoms-rich COFs possessed many excellent properties,including high thermal stability and abundant binding sites. Among them, PB-TT COF exhibited ultra-high iodine uptake up to 5.97 g/g in vapor, surpassing most of adsorbents previously reported, which was ascribed to its high specific surface(1305.3 m2/g). Interestingly, PA-TT COF with low specific surface(48.6m2/g) showed good adsorption ability for iodine in cyclohexane solution with uptake value of 750 mg/g,which was 2.38 times higher than that obtained with PB-TT COF due to its unique sheet-like morphology.Besides, the two COFs possessed good reusability, high selectivity and iodine retention ability. Based on experimental results, the adsorption mechanisms of both COFs were studied, revealing that iodine was captured by the physical-chemical adsorption. Furthermore, the both COFs showed excellent adsorption ability in real radioactive seawater treated safely, demonstrating their great potential in real environment.

Comparison of luminescent properties of helicene-like bibenzothiophenes with o-carborane and 5,6-dicarba-nidodecaborane

This article describes comparison of the anchoring effect on electronic properties of the helicene-like bibenzothiophene between o-carborane and 5,6-dicarba-nido-decaborane. The o-carborane and nido-decaborane-fused bibenzothiophenes were simultaneously obtained in the same reaction and successfully isolated. Initially, the X-ray single crystal analysis revealed that the helicene-like distorted structure was realized in the nido-decaborane-fused bibenzothiophene. From optical measurements in the solution state, distinct different characteristics depending on the type of anchors were observed. It was summarized that the absorption and luminescent properties originated from weak π-conjugation at the bibenzothiophene moiety in the o-carboranefused compound were obtained, whereas robust π-conjugation and significant emission from the intramolecular charge transfer state were detected from the nido-decaborane-fused compound. These data can be explained by the theoretical results that π-conjugation was restrictedly developed within the bibenzothiophene moiety in frontier orbitals of the o-carborane-fused compound. In contrast, π-conjugation can be constructed even through the distorted bibenzothiophene because of the nido-decaborane unit. Moreover, the intramolecular charge transfer state should be realized because of electronic interaction involving the nido-decaborane unit in the excited state. Furthermore, it was demonstrated that the nido-decaborane-fused compound possessed solid-state emission and mechanochromic luminescent properties. The π-conjugation on the distorted structure supported by the nido-decaborane anchor should play a significant role in suppressing aggregation-caused quenching followed by presenting solid-state emission with stimuli responsiveness.

Research Advances in Helicene Structure-Based Chiral Luminescent Materials and Their Circularly Polarized Electroluminescence

Benefited from direct generation of circularly polarized(CP) emission with tunable colors, high efficiencies and facile device architectures, CP organic light-emitting diodes(CP-OLEDs) have attracted great attention and are expected to meet industrial applications. Particularly, CP electroluminescence(CPEL) originated from CP-OLEDs has wide potential applications in 3D displays, optical information storage, quantum communication, and biological sensors. The diverse design strategies of chiral luminescent materials for CP-OLEDs, including small organic emitters, lanthanide and transition-metal complexes and conjugated polymers, have been extensively explored. Helicene with twisted extended π-conjugated molecular structure could exhibit special helical chirality and excellent circularly polarized luminescence properties, which has been employed as the ingenious chirality core for constructing efficient chiral luminescent materials. In addition, significant improvements have been made in terms of CP photoluminescence research, however, the development of CPEL with more application prospects in optoelectronic technology still lags behind. In this review, we systematically summarize the recent advances in chiral luminescent materials based on helicene structure and their CPEL properties, including helicene-based chiral fluorescence molecules, transition metal complexes and thermally activated delayed fluorescence molecules, and discuss current challenges and future perspectives for this hot research field. We believe this progress report will provide a promising perspective of OLEDs based on helicene emitters with CPEL properties for extensive researchers, including chemical, physical and material scientists in different disciplinary fields and attract them to this rapidly developing field.

Simple Double Hetero[5]helicenes Realize Highly Efficient and Narrowband Circularly Polarized Organic Light-Emitting Diodes

Helicene-based emitters with unique inherent circularly polarized luminescence(CPL)are promising yet remain a formidable challenge for highly efficient circularly polarized organic light-emitting diodes(CP-OLEDs),ascribed to their tough synthesis,low emission efficiency,and easy racemization in the thermal deposition process.Herein,a pair of helicenebased enantiomers,namely(P)-helicene-BN and(M)-helicene-BN,were developed,which merge helical chirality and the B/N/S inserted polycyclic aromatic framework to concurrently feature CPL and narrow thermally activated delayed fluorescence(TADF)characteristics.Benefiting from the excellent thermal/photophysical/chiroptical properties,the narrowband green CP-OLEDs based on enantiomers achieved maximum external quantum efficiencies(EQE_(max))of up to 31.5%,and dissymmetry factor(|g_(EL)|)of 2.2×10^(−3).This work reveals the great potential of helicene-based emitters in CP-OLEDs.