Bei四羧酸二酰亚胺系有机光导材料的光敏性与结构的关 …

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存在定量构效关系，ｒ〉０．９５；双取代化合物的光敏性与ＣＧＬ到ＣＴＬ的空穴注入效率存在ＱＳＰＲ，ｒ〉０．９７。     

1-取代恶唑-2-取代苯基乙烯类电荷传输材料的光敏性与结构的 关系研究

应用AM1方法全优化了11种电荷传输材料的稳定构型。根据Law提出空穴注入轨道模型,研究了光敏性E~5~0与电荷传输材料和电荷传输材料的HOMO能级差ΔE~T~-~G的关系。计算结果表明,lgE~5~0与ΔE~T~-~G存在线性关系。采用成键能较低构型的HOMO能级得到的相关性(r=0.837)优于成键能较高构型的HOMO能级得到的相关性(r=0.728)。增加空穴传输活性氮原子的净电荷后,相关性被进一步提高(r=0.911)。这表明分层光感受器的光敏性与光电转换的后两个过程都相关,其中从电荷产生层(CGL)到(CTL)电荷传输层的空穴注入效率占主导作用,空穴在CTL中的迁移率也至关重要。     

1-取代恶唑-2-取代苯基乙烯类电荷传输材料的光敏性与结构的 关系研究

应用AM1方法全优化了11种电荷传输材料的稳定构型。根据Law提出空穴注入轨道模型,研究了光敏性E~5~0与电荷传输材料和电荷传输材料的HOMO能级差ΔE~T~-~G的关系。计算结果表明,lgE~5~0与ΔE~T~-~G存在线性关系。采用成键能较低构型的HOMO能级得到的相关性(r=0.837)优于成键能较高构型的HOMO能级得到的相关性(r=0.728)。增加空穴传输活性氮原子的净电荷后,相关性被进一步提高(r=0.911)。这表明分层光感受器的光敏性与光电转换的后两个过程都相关,其中从电荷产生层(CGL)到(CTL)电荷传输层的空穴注入效率占主导作用,空穴在CTL中的迁移率也至关重要。     

分子间相互作用对苯甲酮类聚集诱导延迟荧光材料性能的影响

合成了4种以吩噁嗪为给体的苯甲酮类发光材料,考察了不同芳烃取代基对材料分子间相互作用及光电性能的影响.研究结果表明,共平面的稠环芳烃修饰会使分子间存在大量的强π-π堆积作用,而三维的三蝶烯基团则能避免这些作用的产生.4种化合物均具有非常高的热稳定性,5%热失重温度(T_d,5)在400℃以上,分子间π-π堆积会明显提高材料的热稳定性.除苝修饰的化合物外,其它3种化合物都具有明显的聚集诱导延迟荧光,单线态-三线态能隙(ΔE_ST)值不超过0.01 eV;光致发光效率高,在PMMA薄膜中的发光效率在0.60～0.78之间,且随分子间作用力的降低先增加后降低.电致发光性能测试结果表明,三蝶烯修饰的化合物的电致发光性能最佳,掺杂器件的最大亮度可达48480 cd/m²,峰值功率效率(PE_max)和峰值外量子效率(EQE_max)分别为54.4 lm/W和19.0%,且非掺杂器件的PE_max和EQE_max依然高达33.5 lm/W和13.4%.这说明...     

量子阱单激子光增益实现超低阈值连续波激光

胶质纳米晶光增益材料对于开发新一代的高效激光器前景巨大.采用外延生长法制备原子尺寸厚度的Ⅱ型CdSe/CdTe复合纳米片,研究该异质结构的光学性质及其对应的电荷动力学过程,以此探讨其光增益性能及激光应用潜能.光谱结果表明,Ⅱ型纳米片有效的电子与空穴分离结构使其表现出较大的斯托克斯位移（△_S=100 meV）和较强的激子-激子库伦排斥力（△_XX=50 meV）.△_S和△_XX的协同效应使"激子-双激子"吸收能相比单激子发射能提高了约150 meV,打破了一般纳米晶结构中两者的简并关系,这将有效抑制光吸收损失并促进单激子光增益.单激子光增益机制下该纳米片较长的单激子寿命（τ_x=394 ns）使连续激光泵浦的理论功率阈值低至12 W/cm²,这为开发实用性更强的、超低阈值的连续波激光器提供可能.     

空间接近二酰胺的多米诺类型反应及其在有机合成中的应用

发现了空间接近的双温勒伯(Weinreb)酰胺与格氏试剂在温和条件下的单取代反应, 该反应普适性强、 操作简便且产率高, 反应存在动力学控制和热力学控制2种产物. 机理分析表明, 该反应发生了分子内亲核取代反应, 并生成了稳定的单取代中间体, 从而避免了双取代反应的发生. 通过该反应制备了一系列4-取代酞嗪酮类化合物, 合成了基于酞嗪基团的纯红光三环金属化铱(Ⅲ)配合物, 采用该配合物制备的有机电致发光器件表现出高效率[最大外部量子效率(EQE_max)=10.3%]和低浓度猝灭性能.     

含亚胺和胆甾烯基不对称液晶二聚体的合成及介晶性

报道含亚胺和胆甾烯基不对称液晶二聚体化合物XC₆H₄N＝CHC₆H₄OC₁₀H₂₀COOCh* [X＝OC_nH_2n＋1, (n＝1～12,14), F, Cl, Br, CH₃] (1a～1q)的合成及液晶性. 目标化合物通过600 MHz ¹H NMR和元素分析进行了结构表征. 其介晶性通过偏光显微镜(POM)和差示扫描量热计(DSC)进行了研究. 结果显示: 所有化合物都具有胆甾相(N*). 对于烷氧基系列(X＝OC_nH_2n＋1), 有部分化合物还呈现了近晶A相(S_A), 且随着末端烷氧链长度的增加, 化合物的清亮点呈现缓慢下降的趋势, 而化合物从胆甾相到各向同性液体转变的熵变(ΔS_N*→I)则呈现奇-偶效应. 同时我们对比研究了取代基X对胆甾相稳定性的影响, 发现取代基X对胆甾相的稳定性高低顺序为: MeO＞Cl＞Br＞Me＞F. 这些结果证实了末端取代基的改变对化合物的相转变温度以及介晶性质有显著的影响.     

紫外臭氧处理增强溶液法MoO3薄膜的空穴注入能力

空穴注入层对有机发光二极管的性能有重要的影响,尤其是当器件中的空穴传输材料的最高占据分子轨道能级较深的时候。近年来有许多关于新型的溶液法空穴注入材料的研究。在本文中,我们对溶液法MoO₃薄膜使用了三种不同的处理方法来研究其对空穴注入性能的影响,即：在空气中150 ℃退火;在空气中150 ℃退火再紫外臭氧处理(UVO) 15 min;只进行UVO处理15 min。结果发现当MoO₃薄膜在空气中150 ℃退火后,器件的电流最小,空穴注入能力最差。而当MoO₃薄膜经过UVO处理后,器件的电流显著增大,工作电压大幅下降,器件性能接近于蒸镀的MoO₃薄膜的器件。更惊喜的是,这种改善在MoO₃薄膜仅作UVO处理后也可获得。经定量计算发现MoO₃薄膜经过UVO处理后的空穴注入效率能提高到约0.1。XPS分析表明通过UVO处理后,MoO₃薄膜中Mo⁵⁺成分减少并且薄膜表面的富氧吸附物被有效地消除,使得其化学计量基本与蒸镀的MoO₃薄膜相同。基于这种经UVO处理的溶液法MoO₃作为空穴注入层,器件的最大电流效率可达到48.3 cd∙A⁻¹。     

吡啶取代蒽衍生物电荷传输性质的理论研究

采用DFT,HF,CIS和TDDFT等方法对5个吡啶取代蒽衍生物的电子结构、光谱及电荷注入传输性能进行了计算与研究.结果表明,5种化合物的结构变化发生在相邻基团之间的二面角,电子光谱变化微小,最大发射波长约450nm.通过调节吡啶或苯的取代位置,可改变前线分子轨道能级、电离能、电子亲和势和重组能的大小,改善化合物的电荷注入传输性能.5种化合物中,DPyPA-MO的空穴和电子迁移速率较为突出,而DPyPA-OM具有最佳的电荷注入传输性能,有望成为电荷平衡性优良的蓝光材料应用于OLED.     

过渡金属五卤苯基有机化合物的研究(Ⅱ)——五氯苯基镍化合物亲核取代反应动力学

本文用分光光度法研究了双(二苯基烷基膦)合(五氯苯基)卤化镍(MX)与NO₂^-和CNS^-在MeOH、EtOH和DMF溶剂中的亲核取代反应动力学.实验表明,反应遵循两项速率定律,即γ=(k₁+k₂[L])[MX].实验分别测定了不同温度下的速率常数k₁、k₂值及对应的活化参数△H^≠和△S^≠值.讨论了反应机理、溶剂效应,以及化合物中的不同烷基膦配体、不同离去基团和不同进入基团对反应速率的影响.     

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.     

4-(1,2-二苯基)乙烯基-4’-(N,N-二苯基-4-乙烯基苯胺基)联苯及其二氟取代衍生物的电子结构与光谱性质

分别采用B3LYP/6-31G(d)和CIS/6-31G(d)方法对4-(1,2-二苯基)乙烯基-4’-(N,N-二苯基-4-乙烯基苯胺基)联苯(A)及其二氟取代衍生物(B-F)的基态(S0)和单重激发态(S1)的几何构型进行了全优化, 计算获得了电离势IP、电子亲和势EA等相关数据, 并采用含时密度泛函(TD-DFT)方法计算了上述化合物的电子吸收和荧光发射光谱. 研究结果表明, 化合物A及二氟取代衍生物B-F在469-474 nm蓝光区域主发射峰的强度远远大于372-387 nm范围的次发射峰, 说明此类化合物具有纯度较高的发射光谱; 主链苯环上的二氟取代(B, C和D)使最低空轨道(LUMO)能级明显降低, 有利于提高电子注入; 芳胺基苯环上的二氟取代(D和E)使分子最高占据轨道(HOMO)能级明显降低, 电离势增加, 能隙变大, 有利于抑制空穴越过发光层向电子传输层输运, 减少界面处激基复合物的形成, 同时起到光谱蓝移的效果; 既是主链苯环上也是芳胺基苯环上的二氟取代衍生物D更有利于平衡电子-空穴的注入, 应该具有更加优良的发光性质.     

方酸衍生物的光敏性与结构关系的理论研究

The geometries of bis(4-dimethylaminophenyl)squaraine and its N and C-2 derivatives have been obtained by AMl and Gaussian 92.The relationship between their photosensitivties and geometries has been studied respectively. The linear relationships between oxidation Potential (EOX) of compounds 1-6 and their HOMO energy (EH), between the Photosensitivity (lgE0.5) of compound 1-5 and ΔET-GOX (the difference of the oxidation potential of charge-transporting material (CTM) and charge-generating material (CGM)), between lgE0.5 and ΔET-G (the difference of the HOMO energy of CGM and CTM) have been studied respectively by the least square fitting method. The result indicates that Eox and EH exhibit certain linearity (r=0.883), the correlation coefficient of lgE0.5 and ΔET-G (r=0.980) is greater than that of lgE0.5 and ET-GOX (r=0.883). It is concluded that the method of calculating the HOMO energy is better than that of detecting the oxidation potential during the study of QSAR of bis(4-dimethylaminophenyl)and its C-2 derivatives. According to the linear relationship obtained by AM1,bis(4-dimethylamino-2,6-fluorophenyl)squaraine has good photosensitivty.     

方酸衍生物的光敏性与结构关系的理论研究

量子化学方法早已成功地运用于探索药物分子的定量构效关系（QSAR）[1，2]，然而通过查阅近十几年的CA，发现用该方法进行有机光导材料（OPC）的QSAR研究工作甚少［3，4］．据推测，造成这种情况的原因是，影响OPC的光导性能的因素太多．例如，化合物的纯度、电行产生层（CGL）厚度、电行产生材料（CGM）与高分子粘结剂的配比、颗粒大小、结晶度、堆积方式、从CGL到电荷传输层（CTL）的空穴注人效率等．这么多的影响因素无疑是量子化学方法研究OPC的难点．随着大量OPCat合成出来及OPC研究的逐步深入，采用量子化学方法探讨化…     

TFA-sensitive arylsulfonylthiourea-assisted synthesis of N,N'-substituted guanidines

An efficient synthesis of N,N'-substituted guanidine derivatives was developed via an aromatic sulfonyl-activated thiourea intermediate. The use of certain aromatic sulfonamides, such as PbfNH(2), as the key reagent to incorporate a TFA-labile guanidine protection group greatly facilitates solid-phase synthesis of N,N'-substituted guanidine compounds.     

A theoretical description of thetrans-cis conversion in the lowest excited states of diimide

The lowest excited states of the diimide molecule have been calculated by three different SCF-type methods, the performances of which are analyzed in regard to the prediction of geometries and energies. The calculations have been performed with two basis sets (STO-3G and 4-31G) both supplemented with more diffuse functions on the N atoms. Lowest energy pathways for thetrans-cis interconversion in the various states are presented for the three calculation methods and for the two basis sets.     

Unsymmetrically N,N'-substituted saturated carbenes: synthesis, reactivity and preparation of a rhodium(I) carbene complex

A versatile synthesis of unsymmetrically N,N'-substituted saturated carbenes is described. The novel racemic imidazolidin-2-ylidenes rac-5 have been synthesized by reductive desulfurization of the corresponding imidazolidin-2-thiones rac-4. The thiones were prepared in two reaction steps from aldimines and secondary amines. Three different substituents at N1, N3 and C4 of the five-membered N-heterocyclic ring can be introduced by choice of suitable aldimines and secondary amines. The dimerization behaviour (diaminocarbene/enetetramine equilibrium) for the unsymmetrically N,N'-substituted imidazolidin-2-ylidenes has been investigated by NMR spectroscopy. Unsymmetrically N-iPr and N-iBu substituted N-heterocyclic carbenes undergo a slow dimerization, whereas N-tBu substituted derivatives are stable as monomeric carbenes indefinitely. The carbene ligand rac-5d has been coordinated to rhodium(I) to give the square-planar rhodium carbene complex [Cl(cod)Rh(rac-5d)]rac-6d which has been characterized by an X-ray diffraction analysis.     

Structural,optical, and charge transport properties of cyclopentadithiophene derivatives: a theoretical study

Density functional theory calculations were carried out to investigate the structural and opto-electronic properties of cyclopenta[2,1-b:3,4-b′]dithiophene (CPDT) derivatives. The ground state, cationic and anionic geometries of cyclopentadithiophene derivatives were optimized at B3LYP/6-311G(d,p) level of theory. Based on these geometries, ionic state properties such as ionization potentials, electron affinities, hole extraction potential, and electron extraction potential of cyclopentadithiophene derivatives have been calculated. The charge transfer integral, spatial overlap integral, and site energy were calculated from the matrix elements of Kohn–Sham Hamiltonian. Computed results show that the mobility of charge carriers in CPDT derivatives is strongly affected by the substitution of electron withdrawing group at bridge-head and α-positions. The excited state geometry of CPDT derivatives were optimized using configuration interaction singles method. On the basis of ground and excited states geometry, absorption and emission spectra of cyclopentadithiophene derivatives were calculated using the time-dependent density functional theory method. It has been observed that the substitution of EWG in cyclopentadithiophene core alters the absorption and emission spectra. The nonlinear optical property of CPDT derivatives have been studied through computed static polarizability and first hyperpolarizability.     

Electronic Interactions of Michler's Ketone with DNA Bases in Synthetic Hairpins

The mechanism and dynamics of photoinduced electron transfer in two families of DNA hairpins possessing Michler's ketone linkers have been investigated by means of steady state and time‐resolved transient absorption and emission spectroscopies. The excited state behavior of the diol linker employed in hairpin synthesis is similar to that of Michler's ketone in methanol solution. Hairpins possessing only a Michler's ketone linker undergo fast singlet state charge separation and charge recombination with an adjacent purine base, attributed to well‐stacked ground state conformations, and intersystem crossing to the triplet state, attributed to poorly stacked ground state conformations. The failure of the triplet to undergo electron transfer reactions on the 7 ns time scale of our measurements is attributed to the low triplet energy and reduction potential of the twisted triplet state. Hairpins possessing both a Michler's ketone linker and a perylenediimide base surrogate separated by four base pairs undergo photoinduced hole transport from the diimide to Michler's ketone upon excitation of the diimide. The efficiency of hole transport is dependent upon the sequence of the intervening purine bases.