Self-assembled helical nanostructures from an asymmetrical perylene diimide

An asymmetrical perylene diimide 3, N-（4-methoxyphenyl）-N＇-（4-nitrophenyl）-perylene-3,4,9,10-tetracarboxylic diimide, was synthesized, and its self-assembly and dissociation behaviors in chloroform was studied in detail by UV-vis and fluorescence spectroscopies. The resulting unique helical nanostructures from 3 were proposed to be self-assembled via the cooperative actions of π-π stacking, steric hindrance and electrophile-nucleophile type pairing.     

二萘嵌苯二酰亚胺衍生物的半导体性质

应用密度泛函理论研究了四种二萘嵌苯二酰亚胺(PDI)(N,N'-二萘嵌苯-3,4,9,10-四羧酸二酰亚胺(1), N,N'-二(3-氯苯甲基)二萘嵌苯-3,4,9,10-四羧酸二酰亚胺(2), N,N'-二(3-氟苯甲基)二萘嵌苯-3,4,9,10-四羧酸二酰亚胺(3)和N,N'-二(3,3-二氟苯甲基)二萘嵌苯-3,4,9,10-四羧酸二酰亚胺(4))半导体材料的最高占据轨道和最低未占据轨道能量、离子化能和电子亲和能以及在电荷传导过程中的重组能. 与化合物2-4的最高占据轨道和最低未占据轨道能量变化相同, 在PDI分子外围引入氯苯甲基或氟苯甲基后导致化合物2-4的绝热电子亲和能有不同程度的增加. 应用Marcus电子传导理论, 计算了这四种半导体材料应用于有机场效应晶体管在电子传递过程中的电子耦合和迁移率. 计算结果表明:这四种化合物相对于金属金电极而言具有较小的电子注入势垒, 是优良的n型半导体材料. 计算的这四种半导体材料的电子传输迁移率分别为5.39, 0.59, 0.023和0.17 cm2·V-1·s-1. 通过研究化合物分子在还原过程中几何结构变化和在化合物3晶体中不同类型的电子传递路径, 合理地解释了化合物1-4在有机场效应晶体管电荷迁移过程中具有较高的电子迁移率.     

Self-assembled aggregates of amphiphilic perylene diimide-based semiconductor molecules: effect of morphology on conductivity

Two amphiphilic perylenetetracarboxylic diimide derivatives modified with different side chains at imide nitrogen, N-n-hexyl-N'-(2-hydroxyethyl)-1,7-di(4'-t-butyl)phenoxy-perylene-3,4:9,10-tetracarboxylic diimide (PDI 1) and N,N'-di(2-hydroxyethyl)-1,7-di(4'-t-butyl)phenoxy-perylene-3,4:9,10-tetracarboxylic diimide (PDI 2), were fabricated into organic nanostructures via solution-phase self-assembly. Their self-assembling properties in methanol and n-hexane have been comparatively studied by electronic absorption, fluorescence, and Fourier transform infrared spectroscopy (FT-IR). The morphologies and structures of the self-assemblies were examined by scanning electronic microscopy (SEM), atomic force microscopy (AFM), as well as X-ray diffraction (XRD) techniques. The conducting properties were evaluated by current-voltage (I-V) measurements. Due to the presence of different number of hydroxyethyl groups in the molecule of PDI 1 and PDI 2, the self-assembly of the two molecules in methanol and n-hexane results in nanostructures with distinctly different morphology as follows: nanobelts and nanoleaves for PDI 1 and nanobelt dendrites and nanosheets for PDI 2, respectively. Analysis of the spectral change for the aggregates relative to that of monomeric PDI in solution revealed that in polar and apolar solvents, both nanobelts and nanoleaves precipitated from PDI 1 adopt the H aggregation mode, whereas nanobelt dendrites and nanosheets from PDI 2 adopt H and J aggregation mode, respectively, implying the effect of both side-chain substituent and solvent on tuning the intermolecular stacking. Furthermore, the conductivity of the aggregates of either PDI 1 or PDI 2 from methanol is more than ca. 1 order of magnitude higher than those from n-hexane. In particular, the well-defined, one-dimensional (1D) nanobelts of PDI 1 show excellent semiconducting property with the electrical conductivity as high as 3.3×10(-3) S cm(-1), which might serve as promising candidates for applications in nano-electronics.     

新型苝酰亚胺衍生物的合成及其光学性能

以3,4,9,10-苝四酸二酐为原料,设计并合成了三个新型的苝酰亚胺衍生物———N,N’-二(1-戊基己基)-3,4,9,10-苝四羧酸二酰亚胺,N,N’-二(1-戊基己基)-1,6,7,12-四(对叔丁基苯氧基)-3,4,9,10-苝四羧酸二酰亚胺和N,N’-二(4-六氟异丙醇基苯基)-1,6,7,12-四(对叔丁基苯氧基)-3,4,9,10-苝四羧酸二酰亚胺,其结构经1H NMR和MS表征。用UV-Vis和荧光光谱研究了他们的光学性质。     

苝四羧酸二酰亚胺衍生物的合成及其性能研究

以苝四羧酸二酐为原料,设计并合成了3个苝四羧酸二酰亚胺类化合物[1,7-二溴-3,4,9,10-苝四酸酐(1), N,N′-二(十二烷基)-1,7-二溴-3,4,9,10-苝四羧酸二酰亚胺(2)和N,N′-二(十二烷基)-1,7-二对叔丁基苯氧基-3,4,9,10-苝四羧酸二酰亚胺(3)],其结构经1H NMR和MS表征.用循环伏安法和热分析法研究了2和3的电化学性质和热学性质.结果表明:2和3的氧化电位分别为931.6 mV, 170.1 mV,还原电位分别为-1 028 mV, -1 941 mV;2和3具有高的分解温度(>300 ℃),有良好的热稳定性.     

Nanobelt self-assembly from an organic n-type semiconductor: propoxyethyl-PTCDI

Nanobelt structures have been fabricated for an n-type semiconductor molecule, N,N'-di(propoxyethyl)perylene-3,4,9,10-tetracarboxylic diimide (PTCDI). The short alkyloxy side chain not only affords effective pi-pi stacking in polar solvents for self-assembling but also provides sufficient solubility in nonpolar solvents for solution processing. As revealed by both AFM and electron microscopies, the nanobelts have an approximately rectangular cross section, with a typical thickness of about 100 nm and a width in the range of 300-500 nm. The length of the nanobelts ranges from 10 to a few tens of micrometers. The highly organized molecular packing (uniaxial crystalline phase) has been deduced from the measurement of electron diffraction and polarized microscopy imaging. The detected optical axis is consistent with the one-dimensional stacking of the molecules.     

萘酞菁锌复合体系的光致电荷转移

合成了萘酞菁锌, 利用傅立叶红外光谱、元素分析和MALDI-TOF质谱等手段表征了分子结构; 循环伏安测试和吸收光谱确认了共轭体系的扩大使分子带隙下降. 根据材料加工性能的不同, 分别采用溶液法、层-层蒸镀(Layer-by-layer evaporation)法和单层分散旋涂法, 将给体分子萘酞菁锌与三种受体分子1-(3-甲氧基羧基)丙基-1-苯 基-[6,6]C61, C60和N,N’-二嘧啶基苝四羧基二酰亚胺进行了复合, 通过研究复合前后荧光变化, 确认了给体-受体两相界面处发生了由分子能级差引发的光致电荷转移, 为制备更宽光伏响应范围的太阳能电池器件提供了潜在的新途径.     

3,4,9,10-Perylenetetracarboxylic Acid Derivatives, Their Spectral Behavior and Their Chemical Interaction with Hydrated Iron Oxide Nanopar

The photophysical properties such as electronic absorption, excitation and emission spectra as well as molar absorptivity and fluorescence quantum yield of N,N‐bis(pyrimidenyl)‐3,4,9,10‐perylenetetracarboxylic diimide (PmPBD), N,N‐bis(pyridenyl)‐3,4,9,10‐perylenetetracarboxylic diimide (PyPBD) and N,N‐bis(4‐methylpyridenyl)‐3,4,9,10‐perylenetetracarboxylic diimide (MPyPBD) have been measured in different solvents. Both electronic absorption and fluorescence spectra are not sensitive to medium polarity, while the fluorescence quantum yield ((_f) is solvent dependent. Perylene derivatives under investigation undergo molecular aggregation to dimmer or larger aggregates in water. Dye solution in dimethylformmaide (DMF) gives laser emission at 565 nm upon pumping with 337.1 nm nitrogen laser pulse. The excitation energy transfer from 7‐dimethylamino‐4‐methylcoumarine (DMC) to PmPBD has been studied to improve the laser emission of PmPBD. The value of energy transfer rate constant (k_ET) and critical transfer distance (R₀) indicate a F?rster type energy transfer mechanism. There is a large interaction between the perylene compounds under investigation and the hydrated nanoparticles in the excited state therefore the fluorescence quenching rate constant of these derivatives by hydrated iron oxide nanoparticles has a large value.     

Synthesis of highly fluorescent and water soluble perylene bisimide

Designed and synthesized a new highly water soluble N,N¹-bis（2-（（5-（（dimethylamino）methyl）furan-2-yl）methylthio）ethyl）-perylene -3,4,9,10-tetracarboxylic diimide from 2-（（5-（（dimethylamino）methyl）furan-2-yl）methylthio）ethanamine and perylene-3,4,9,10- tetracarboxylic dianhydride.The compound was characterized by ¹H,¹³C,2D NMR,mass and IR techniques.The compound is highly fluorescent with good solubility in water and other polar solvents.     

N,N’-二(2-吡啶基)-1,6,7,12-四(4-叔丁基苯氧基)-3,4:9,10-苝酰亚胺的合成、表征及性能研究

优化了N,N’-二(2-吡啶基)-1,6,7,12-四(4-叔丁基苯氧基)-3,4:9,10-苝酰亚胺的合成方法, 得到一种简单有效的在苝酰亚胺的酰胺和bay位置同时取代的方法. 对其结构进行了表征, 研究了其溶液态和薄膜态的光学性质和电化学性质. 并且对其能级结构和电荷分布进行了分子模拟.     

水溶性苝系衍生物荧光探针的合成及对金属离子的识别

用苝四酸酐为反应物,在酸酐位置上引入天冬氨酸,合成了水溶性的含4个羧基的荧光苝二酰亚胺衍生物:N,N'-二天冬氨酸铵盐-3,4,91,0-苝四羧酸二酰亚胺(PTCDA).在水溶液中与Fe3+、Al3+、Pb2+和Cu2+等金属离子反应,吸收光谱发生红移,荧光淬灭.当加入等量Hg2+、Zn2+、Ni2+、Co2+、Mn2+和Mg2+等金属离子后不干扰荧光反应,有选择性好、灵敏度高等特点.并探讨了衍生物的荧光反应机理,表明有好的应用价值和广阔发展前景。     

苝四羧酸二酰亚胺系有机光导材料的光敏性与结构的关系研究

用AM1和CNDO方法优化得PTCAs可能存在的稳定结构.对比晶体结构发现化合物3-5晶体中以成键能较高的共面结构存在,该结构有利于形成分子的紧密堆积.最小二乘法拟合结果表明单取代化合物的光敏性与分子激发跃迁能(△E_L-H)存在定量构效关系(QSPR),r＞0.95;双取代化合物的光敏性与从CGL到CTL的空穴注入效率(△E_T-G)存在QSPR,r＞0.97.表明光电转换两个过程在不同类型PTCAs的光敏性产生过程中占据的作用不同:分子激发难易是影响单取代化合物光敏性的主要因素;而空穴注入效率是影响双取代化合物光敏性的主要因素.     

苝四羧酸多联体化合物的合成及其光谱特性研究

本文合成了8个 四羧酸多联体化合物;测定了这些化合物的吸收光谱、荧光光谱。研究了由供电子分子键连的多联体分子的光谱特性及其分子体系内稳态荧光猝灭机理。首次从吸收光谱和荧光光谱上分析和考察了四羧酸多联体化合物分子体系内的光致电子转移反应。     

Photoinduced electron transfer and nonlinear absorption in poly(carbazole-alt-2,7-fluorene)s bearing perylene diimides as pendant acceptors

This paper reports the synthesis, photophysical behavior, and use in nanosecond optical-pulse suppression of a poly(2,7-carbazole-alt-2,7-fluorene) and a poly(3,6-carbazole-alt-2,7-fluorene) in which the carbazole N-positions are linked by an alkyl chain to one of the nitrogen atoms of a perylene-3,4,9,10-tetracarboxylic diimide (PDI) acceptor. It was found that the PDI pendants on the polymer side chain aggregated even in dilute solution, which extended the onset of PDI absorption into the near-infrared (NIR). Transient-absorption spectra of these polymers provide evidence for efficient electron transfer following either donor or acceptor photoexcitation to form long-lived charge-separated species, which exhibit strong absorption in the NIR. The spectral overlap between the transient species and the long-wavelength absorption edge of the aggregated PDI leads to reverse saturable absorption at 680 nm that can be used for optical-pulse suppression. Additionally, at high input energies, two-photon absorption mechanisms may also contribute to the suppression. PDI-grafted polymers exhibit enhanced optical-pulse suppression compared with blends of model materials composed of unfunctionalized poly(carbazole-alt-2,7-fluorene)s and PDI small molecules.     

Photophysical properties and semiempirical calculations of perylene-3,4,9,10-tetracarboxylic tetramethylester (PTME)

The spectral behavior and fluorescence quantum yield of perylene-3,4,9,10-tetracarboxylic tetramethylester (PTME) have been measured in different solvents. Both electronic absorption and fluorescence spectra are not sensitive to medium polarity. The dye exhibits high fluorescence quantum yield and high photostable. Crystalline solid of PTME gives excimer-like emission at 530 nm. The laser activity of PTME has been investigated. The dye solution in N,N-dimethylformamide (DMF) gives laser emission around 480 nm upon excitation by 337.1 nm nitrogen laser pulse. The excitation energy transfer from 7-dimethylamino-4-methylcoumarine (DMC) to PTME has also has been studied and the value of energy transfer rate constant, k(ET), and critical transfer distance, R(0) indicate a F?rster-type mechanism. The photodecomposition of PTME in chloromethane solvents has been also studied. We applied semiempirical MO calculations using (PM3 and ZINDO-CI) calculations to explain the geometric and electronic behaviors of the PTME molecule in both ground and excited states and make a correlation with the experimental observations.     

Spectral properties and G-quadruplex DNA binding selectivities of a series of unsymmetrical perylene diimides

A series of new unsymmetrical perylene diimides have been synthesized to investigate their binding selectivities to G-quadruplex DNA structure, a unique four-stranded DNA motif, which is significant to the regulation of telomerase activity. The structures of the perylene diimides have been characterized by IR spectrophotometer, ¹H NMR, ¹³C NMR, MS, TGA and time-resolved instruments. Spectrochemical behaviors have been investigated by visible absorption and fluorescence emission spectra. The spectral characterization of the compounds has been investigated in five common organic solvents of different polarity and in water (in 170 mM phosphate buffer at pH 6). Marked red shifts of absorbance and fluorescence emission bands of the compounds in aqueous solution are compared with the other organic solutions. The fluorescence quantum yields are determined low in more polar solvents and also calculated to be about less than about 0.05 in aqueous solution because of the aggregation effects. Photodegradation rate constants (k_p) of the synthesized compounds have been compared under xenon lamp irradiation in acetonitrile solution.Binding abilities of the synthesized perylene diimides to different form of DNA strands have been investigated by visible absorption and fluorescence spectroscopy in the phosphate buffer solutions. Also, pH-dependent aggregation and G-quadruplex DNA binding selectivity of these ligands have been compared. Among these ligands, N-(2,6-diisopropylphenyl)-N′-(4-pyridyl)-perylene-3,4,9,10-tetracarboxylic diimide (PYPER) has been found to be the most selective interactive ligand for G-quadruplex formed in the G4′-DNA structure. PYPER has shown a significant selectivity to G4′-DNA which is comprised of d(TTAGGG) repeats, known as human telomeres, in the phosphate buffer at pH 6. The absorption maximum of the PYPER/G4′-DNA complex has given bathochromic shift of 7 nm with respect to the absorption maximum of DNA-free solution of PYPER in phosphate buffer at pH 6. Fluorescence quenching experiments between PYPER and G4′-DNA show that PYPER demonstrates about a 9.3-fold selectivity for binding to G4′-DNA versus ds-DNA base pairs with the bimolecular rate constant of 0.95 × 10¹² M⁻¹ s⁻¹.     

A chiral pinwheel supramolecular network driven by the assembly of PTCDI and melamine

The mixing of perylene-3,4,9,10-tetracarboxylic diimide (PTCDI) and 1,3,5-triazine-2,4,6-triamine (melamine) at room temperature in a ratio of 3 : 4 on Au(111) leads to the formation of a new chiral "pinwheel" structure.     

Self-assembly and optical properties of N N′-bis(4-(1-benzylpiperidine))perylene-3,4,9,10-tetracarboxylic diimide

Well-defined nanobelts with strong fluorescence were fabricated from a perylene tetracarboxylic diimide molecule modified with specific side-chain substitution. The new perylene diimide was characterised by ¹H, ¹³C NMR, mass and IR spectral techniques. The photophysical and electrochemical properties were investigated by UV–vis absorption, fluorescence, differential scanning calorimetry and cyclic voltammetry. 1D nanobelt self-assembly of the compound was studied with optical, fluorescence and scanning electron microscopic techniques. The observed self-assembly was supported by computational studies using density functional theory and natural bond order analysis. The optimised molecule was fit into crystal space theoretically, and the observed band gap was correlated well with optical and electrical properties.     

Non-classical control of solid-state aggregation-induced enhanced circularly polarized luminescence in chiral perylene diimides

Organic fluorescent molecules are gaining importance because of their potential applications in many devices. Optically active N,N′-bis((1R)-1-naphthylethyl)perylene-3,4,9,10-tetracarboxylic diimide [(R,R)-1-BNP] and N,N′-bis((1R)-2-naphthylethyl)perylene-3,4,9,10-tetracarboxylic diimide [(R,R)-2-BNP] and their antipode, [(S,S)-1-BNP and (S,S)-2-BNP], emit aggregation-induced enhanced (AIEnh) circularly polarized luminescence (CPL) on both a solid organic polymer film (poly(methyl methacrylate)) and solid inorganic KBr pellet. An opposite chirality is essential for generating CPL of inverted sign. However, a pair of enantiomeric organic molecules may not always be easy to prepare. Interestingly, the chiral perylene fluorophores synthesized in this study can emit both positive and negative AIEnh-CPL in the solid state, depending on their position on the naphthylene groups. In addition, no CPL was observed in these compounds from their dilute solutions.     

Ultraselective fluorescent sensing of Hg2+ through metal coordination-induced molecular aggregation

A new type of fluorescent sensor has been developed from a perylene based molecule, N,N'-dideoxythymidine-3,4,9,10-perylene-tetracarboxylic diimide (TT-PTCDI); the strong, highly selective binding between the thymine ligand (T) and Hg2+ ion enables efficient sensing of mercury ions based on a fluorescence quenching mechanism, which is primarily caused by metal-coordination induced molecular aggregation.