氮杂环配体对卤化亚铜配合物发光机制影响的理论研究

为深入探讨卤化亚铜配合物的发光机制，运用密度泛函理论和含时密度泛函理论的计算方法研究了三个结构相似的溴化亚铜配合物(CuBr-py、CuBr-iq、CuBr-nap)。研究结果表明，CuBr-py和CuBr-nap,电子和空穴重叠程度小，导致其ΔE_ST较小；S₁与T₁间的重组能较小，使其可快速地完成反系间窜越过程，实现热活化延迟荧光(TADF)。此外，与CuBr-nap相比，CuBr-py自旋轨道耦合作用强，其磷光速率也较大，因此其具有TADF和磷光双通道发光特性。而CuBr-iq中喹啉环的存在增大了电子和空穴的重叠程度，ΔE_ST增大；同时S₁与T₁间的重组能较大，T₁无法顺利通过RISC过程回到S₁,导致其最终呈现出磷光特性。这些理论计算结果与实验现象一致，且揭示了N杂环配体结构对于卤化亚铜配合物发光机制的影响规律，为设计和合成稳定高效的发光材料提供了有价值的理论指导。     

推、拉电子基团对水杨醛缩胺分子电子结构和非线性光学性质的影响

采用量子化学半经验FF／PM3方法,讨论了水杨醛缩苯胺分子中两苯环的对位被推、拉电子基团取代后,体系电子结构和非线性光学性质的变化,考查了分子电子结构对非线性光学性质影响的微观本质,得到的具有给体－共轭桥键－受体型结构的水杨醛缩苯胺分子应显示良好的非线光学性质。     

以1,3-茚二酮为电子受体的热激活延迟荧光分子的合成及其在有机发光二极管中的应用

本文设计合成了一种新型电子受体2,2-二甲基-1,3-茚二酮,并将其应用于热激活延迟荧光(TADF)分子的设计中,合成了一系列具有不同发光性能的TADF分子:5-二甲基吖啶基-2,2-二甲基-1,3-茚二酮(IDYD),5-吩噁嗪基-2,2-二甲基-1,3-茚二酮(IDPXZ)和5,6-二吩噁嗪基-2,2-二甲基-1,3-茚二酮(ID2PXZ)。以IDYD为客体掺杂制备得到蓝光OLED器件,其CIE值为(0.27,0.31),最大外量子效率(EQE)为2.13%。以IDPXZ为客体掺杂得到橙光OLED器件,其CIE值为(0.43,0.53),EQE为1.31%。以ID2PXZ为客体掺杂得到黄光OLED器件,其CIE值为(0.41,0.54),EQE为2.55%。上述结果证明了以2,2-二甲基-1,3-茚二酮为电子受体可以得到不同发光颜色的TADF分子,并在全色OLED器件中具有一定应用前景。     

供/吸电子基团共轭桥联的双BODIPY衍生物的合成及性能

设计合成了4种对称的以不同供/吸电子基团为共轭桥、两端连接meso位苯或噻吩取代的新型氟化硼二吡咯甲川(BODIPY)衍生物;通过1H NMR,13C NMR和MS等手段对其进行了结构表征;并采用紫外吸收光谱、荧光发射光谱及循环伏安(CV)等方法研究了其光电性能.紫外光谱数据表明,BODIPY结构具有明显的特征吸收,中间的桥联基团无论是强供电子的苯并二噻吩(BDT)还是强吸电子的苯并噻二唑(BT)均不能使整个分子产生明显的分子内电子迁移(ICT).另一方面,meso位的取代基可与BODIPY核产生微弱的ICT,且meso位噻吩取代的分子比meso位苯环取代的分子表现出更强的ICT.紫外光谱数据和电化学测试结果表明,meso位噻吩取代的分子比meso位苯环取代的分子具有更低的氧化电位和更窄的能隙.     

给、吸电子基团对吡嗪衍生物电子结构影响的DFT研究

采用B3LYP方法在6—31G^#基组水平上优化了对位取代吡嗪衍生物的几何构型，利用TD—DFT方法计算了它们的前线分子轨道能级和电子光谱．结果表明，带有给、吸电子基团对吡嗪衍生物与苯、吡啶相比，也具有很好的共轭性；随着分子共轭链的增长，分子的偶极矩增大，前线分子轨道能级差减小，最大吸收波长发生红移．对于具有相同共轭链的同分异构体，推电子基团与具有给电子性质的共轭链相连，则分子的电荷转移明显，导致偶极矩增大，前线分子轨道能级间的电子跃迁更容易；吸电子基团与具有给电子性质的共轭链相连，情况正好相反，这些结果对分子设计有重要意义。     

吸电子基团调控苯基喹啉类铱配合物的合成及光物理性能

以2,2,6,6-四甲基庚二酮(tmd)为辅助配体,2,4-二取代基苯基-4-甲基喹啉(2,4-2R-mpq)为主配体,在主配体中苯基的2位和4位同时引入氟(F)、甲氧基(MeO)或三氟甲基(CF₃),合成出3个铱磷光配合物(2,4-2R-mpq)₂Ir(tmd)(R=F (1)、MeO(2)、CF³(3))。通过元素分析、核磁共振谱和单晶X射线衍射表征了配合物的组成和分子结构。通过紫外可见吸收光谱、光致发光光谱和理论计算对配合物的光物理性能进行了研究。结果表明：3个配合物的晶体均为三斜晶系,空间群均为■,呈稍微扭曲的八面体构型。配合物1、2和3在溶液状态下的发射波长分别为570、582和604 nm,溶液中量子产率分别为96%、80%和80%。在主配体中苯基的2位和4位同时引入F或MeO,配合物电子云发生聚集,而引入CF₃,配合物的电子云分散。与配合物3相比,配合物1和2的发射波长发生了显著的蓝移。     

蓝光材料Ir(Ⅲ)配合物的磷光效率与光谱的振动关联函数研究

由于发光效率低和稳定性差,蓝色磷光材料一直是发光材料研究领域的瓶颈.为了更深层次地理解蓝色磷光分子结构与发光效率之间的关系,本工作结合密度泛函理论,运用作者新近发展的系间窜越速率的振动关联函数计算方法,定量研究了新型蓝光发射分子fac-tris(2-(4,6-difluorophenyl)pyridyl iridium(fac-Ir(F2ppy)3)的磷光光谱、辐射跃迁和无辐射跃迁速率及其与温度的依赖关系,计算结果很好地解释了实验测量结果.计算表明:(1)相较于未取代的绿光材料fac-Ir(ppy)3,杂原子F的引入增加了T1与S0的能隙,使得光谱蓝移,但没有带来额外的分子结构弛豫的重整能,从而使得该蓝色材料保持了高的发光效率;(2)无辐射跃迁过程所耗散的电子激发态能量主要是通过配体L1中的连接氟化苯环和吡啶环的C(5)—C(46)键、吡啶环内C(43)—C(44)键和C(42)—C(47)键及氟化苯环内的C(3)—C(6)键的伸缩振动,因此,理论研究表明可以通过分子设计来抑制这些振动来进一步提高这类材料的发光效率.     

生物体系中电子转移机理的研究Ⅱ: 分子间电子转移及 电子供、受体间不同基 团的影响

利用自编程序MOPAC-ET中AM1方法,及KT(Koopman'sTheorem)法,研究了二苯负离子体系的分子间电子转移现象,计算了其电子供、受体在不同距离下的V~A~B及它们之间的相关性,另外,还对两苯环间不同介入基团对电子转移的影响做了初步研究,发现不同的介入基团存在着较大的差异。     

生物体系中电子转移机理的研究Ⅱ: 分子间电子转移及 电子供、受体间不同基 团的影响

利用自编程序MOPAC-ET中AM1方法,及KT(Koopman'sTheorem)法,研究了二苯负离子体系的分子间电子转移现象,计算了其电子供、受体在不同距离下的V~A~B及它们之间的相关性,另外,还对两苯环间不同介入基团对电子转移的影响做了初步研究,发现不同的介入基团存在着较大的差异。     

吡啶基团的对称性和离子化对分子双光子吸收截面的影响

采用超快速激光光谱方法研究了含吡啶基团的四个联苯乙烯衍生物及两个杂环分子(A: 4,4’-二(2-(4-吡啶基)乙烯)联苯; B: 4,4’-二(2-(2-吡啶基)乙烯)联苯; C: 1-甲基-4-(2-(4’-(2-(4-吡啶基)乙烯基)-4-联苯)乙烯基)吡啶碘盐; D: 1-甲基-2-(2-(4’-(2-(2-吡啶基)乙烯基)-4-联苯)乙烯基)吡啶碘盐; E: 4-(2-(9-丁基-9氢-3-咔唑)乙烯基)-1-甲基吡啶碘盐; F: 4-(2-(9-丁基-9氢-3-咔唑)乙烯基)-1-甲基喹啉碘盐)的结构-性能关系. 实验结果显示双光子吸收截面最大的是分子E, 高达617.3 GM; 最小的是分子B, 为19.3 GM(1 GM=10^-50 cm⁴·s·photon^-1). 实验研究结果表明, 分子中吡啶基团的对称性及其离子化对分子双光子吸收截面起很重要的作用; 进一步用理论计算证实了以上实验结论并对其机制进行了分析讨论.     

A TD‐DFT Study on the Effect of Intermolecular Hydrogen Bonding on the Photophysical Properties of N‐Methyl‐1,8‐naphthalimide

The effect of intermolecular hydrogen bonding on the photophysical properties of N‐methyl‐1,8‐naphthalimide ( 2 ) has been investigated by time‐dependent density functional theory (TD‐DFT) method. The UV and IR spectra of 2 monomer and its hydrogen‐bonded complexes formed with 2,2,2‐trifluoroethanol (TFE) 2 +TFE and 2 +2TFE have been calculated, which confirm the presence of intermolecular hydrogen bonding interactions between the carbonyl groups of the aromatic imide and the hydroxyl group of the polyfluorinated alcohol. The absorption and fluorescence intensities going from 2 monomer via hydrogen‐bonded complex 2 +TFE to 2 +2TFE were found to be gradually enhanced with the wavelength gradually red‐shifted. The enhancements of the fluorescence intensities from 2 monomer to hydrogen‐bonded complexes 2 +TFE and 2 +2TFE were attributed to the decrease of the intersystem crossing (ISC) efficiency from the first excited singlet state S₁ ¹(ππ*) to the second excited triplet state T₂ ³(nπ*), whose energy was increased relative to its ground state due to the intermolecular hydrogen bonding interactions.     

Synthetic Control of Spectroscopic and Photophysical Properties of Triarylborane Derivatives Having Peripheral Electron‐Donating Groups

The spectroscopic and photophysical properties of triarylborane derivatives were controlled by the nature of the triarylborane core (trixylyl‐ or trianthrylborane) and peripheral electron‐donating groups (N,N‐diphenylamino or 9H‐carbazolyl groups). The triarylborane derivatives with and without the electron‐donating groups showed intramolecular charge‐transfer absorption/fluorescence transitions between the π orbital of the aryl group (π(aryl)) and the vacant p orbital on the boron atom (p(B), π(aryl)–p(B) CT), and the fluorescence color was tunable from blue to red by the combination of peripheral electron‐donating groups and a triarylborane core. Detailed electrochemical, spectroscopic, and photophysical studies of the derivatives, including solvent dependences of the spectroscopic and photophysical properties, demonstrated that the HOMO and LUMO of each derivative were determined primarily by the nature of the peripheral electron‐donating group and the triarylborane core, respectively. The effects of solvent polarity on the fluorescence quantum yield and lifetime of the derivatives were also tunable by the choice of the triarylborane core.     

4—甲基—7—羟基香豆素的发光特性研究

对比考察了多种溶剂介质中不同浓度４－甲基－７－羟基香豆素溶液的荧光光谱特性，发现其谱形状与峰位不仅随溶剂性质而异，且随浓度而变，在某些氢键溶剂中，激发光谱随浓度有很大变化，且发射光谱间存在某种内在联系。基于溶剂本身的性质及４－甲基－７－羟基香豆素在氢键溶剂中的二聚作用讨论了这种现象，本文还考察了这种香豆素衍生物在滤纸及聚酰胺膜基质上，以Ｐｂ（Ａｃ）２或Ｐｂ（ＮＯ３）２作重原子微扰剂时的室温磷光特性     

Influence of Electron Donating Ability on Reverse Intersystem Crossing Rate for One Kind of Thermally Activated Delayed Fluorescence Molecules

First-principles calculations are applied for investigating influence of electron donating ability of donor groups in eight thermally activated delayed fluorescence (TADF) molecules on their geometrical structures and transition properties as well as reverse intersystem crossing (RISC) processes. Results show that the diphenylamine substitution in the donor part can slightly change the bond angle but decrease bond length between donor and acceptor unit except for the lowest triplet state (T\begin{document}$_1$\end{document}) of carbazole-xanthone molecule. As the electron donating ability of donor groups is increased, the overlap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) is decreased. As the diphenylamine groups are added in donor part, the delocalization of HOMO is enlarged, which brings a decreased energy gap (\begin{document}$\Delta E$\end{document}\begin{document}$_{\text{S}_1\text{-T}_1}$\end{document}) between the lowest singlet excited state (S\begin{document}$_1$\end{document}) and T\begin{document}$_1$\end{document} state. Furthermore, with the calculated spin-orbit coupling coefficient (\begin{document}$H_{\text{so}}$\end{document}), one finds that the larger value of \begin{document}$\displaystyle{\frac{\langle S_1|\hat{H}_{\text{so}}|{T}_1\rangle^2}{\Delta E_{\text{S}_1\text{-T}_1}^2}}$\end{document} is, the faster the RISC is. The results show that all investigated molecules are promising candidates as TADF molecules. Overall, a wise molecular design strategy for TADF molecules, in which a small \begin{document}$\Delta E_{\text{S}_1\text{-T}_1}$\end{document} can be achieved by enlarging the delocalization of frontier molecular orbitals with large separation between HOMO and LUMO, is proposed.     

Chiral discrimination of quinine and quinidine based on notable room temperature phosphorescence lifetime differences with γ-cyclodextrin as chiral selector

Upon addition of small amount of bromocyclohexane (BrCH), quinine (QN) and quinidine (QD) display strong room temperature phosphorescence (RTP) in γ-cyclodextrin (γ-CD) solution without deoxygenation. The associated phosphorescence decay curves can be best fitted to biexponential patterns and quite different RTP lifetimes are obtained for QN (86.9 and 12.5 ms) and QD (12.1 and 4.17 ms), indicating a distinct chiral discrimination of γ-CD toward this pair of pseudo-enantiomers. The corresponding association constants evaluated for QN/γ-CD/BrCH and QD/γ-CD/BrCH are 3.47 × 10⁵ and 4.67 × 10⁴ L mol⁻¹, respectively. It can be inferred that their different ability to form complexes with the chiral γ-CD is accounted for the notable difference in RTP lifetimes between QN and QD.     

Synthesis and Photophysical Properties of 3,6-Diphenyl-9-hexyl-9<Emphasis Type="Italic">H</Emphasis>-carbazole Derivatives Bearing Electron Withdrawing Groups

Summary. 3,6-Diphenyl-9-hexyl-9H-carbazole derivatives bearing electron withdrawing groups, such as the formyl or the nitro-group in 4-positions of the phenyl substituents, were prepared and characterized. Their photophysical properties were evaluated and compared with those of the unsubstituted counterpart 3,6-diphenyl-9-hexyl-9H-carbazole. The electron withdrawing groups bearing compounds exhibited considerable red shifts of the absorption and the emission maxima. While 3,6-di(4-nitrophenyl)-9-hexyl-9H-carbazole emitted in the orange region of the visible spectrum with its emission maximum peaking at 585 nm, 3,6-di(4-formylphenyl)-9-hexyl-9H-carbazole gave a pure blue emission with a luminescence quantum yield of 95% peaking at 450 nm. Observed features were explained using quantum mechanical calculations and organic light emitting diodes using the formylphenyl substituted compound as emissive layer were built demonstrating the practical applicability of this class of compounds.     

Tuning the Photophysical Properties of BODIPY Molecules by π‐Conjugation with Fischer Carbene Complexes

The synthesis, structure, and photophysical properties of novel BODIPY–Fischer alkoxy‐, thio‐, and aminocarbene dyads are reported. The BODIPY chromophore is directly attached to the carbene ligand by an ethylenic spacer, thus forming donor–bridge–acceptor π‐extended systems. The extension of the π‐conjugation is decisive in the equilibrium geometries of the dyads and is clearly reflected in the corresponding absorption and emission spectra. Whereas the BODIPY fragment is mainly isolated in aminocarbene complexes, it is fully conjugated in alkoxycarbene derivatives. The former thus exhibit the characteristic photophysical properties of BODIPY units, whereas complete suppression of the BODIPY fluorescence emission is observed in the latter, as a direct consequence of the strong electron‐accepting character of the (CO)₅M?C moiety. As the π‐acceptor character of the metal–carbene group can be modified, the electronic properties of the conjugated BODIPY can be tuned. Density functional calculations have been carried out to gain insight into the photophysical properties.     

两种水溶性钯卟啉磷光探针的在位合成及其发光光谱特性研究

本文探索了合成水溶性钯卟啉(Pd—TAPP和Pd—TSPP)的最佳实验条件,通过紫外可见光谱、荧光光谱和室温磷光光谱研究了合成情况,并考察了其在不同有序介质中的室温磷光特性。     

卤素原子的引入对二苯甲基自由基光稳定性、光物理性质及电致发光器件性能的影响

通过在N-咔唑基-二(2,4,6-三氯苯)甲基自由基(Cz BTM)的咔唑基团的3和6位引入卤素原子,合成了3个新的自由基分子(3,6-二氟-N-咔唑基)二(2,4,6-三氯苯)甲基自由基(F₂CzBTM)、(3,6-二氯-N-咔唑基)二(2,4,6-三氯苯)甲基自由基(Cl₂CzBTM)及(3,6-二溴-N-咔唑基)二(2,4,6-三氯苯)甲基自由基(Br₂CzTM).通过对比3个自由基分子与CzBTM的理论计算结果、电化学性质、光物理性质以及光稳定性,发现对于电子给-受体型的发光自由基,其光物理性质是外围取代基团的电负性和分子空间构型共同作用的结果.Cl₂CzBTM和Br₂CzTM具有较高的光致发光荧光量子效率,而F₂CzBTM在光照下具有最长的光致发光半衰期.与以CzBTM为发光层制备的电致发光器件相比,以Cl₂CzBTM和Br₂CzTM为发光层制备的有机电致发光器件的光谱均发生了蓝移,器件的最大外量子效率...     

Tuning the Properties of Graphdiyne by Introducing Electron‐Withdrawing/Donating Groups

The properties of graphdiyne (GDY), such as energy gap, morphology, and affinity to alkali metals, can be adjusted by including electron‐withdrawing/donating groups. The push–pull electron ability and size differences of groups play a key role on the partial property adjusting of GDY derivatives MeGDY, HGDY, and CNGDY. Cyano groups (electron‐withdrawing) and methyl groups (electron‐donating) decrease the band gap and increase the conductivity of the GDY network. The cyano and methyl groups affects the aggregation of GDY, providing a higher number of micropores and specific surface area. These groups also endow the original GDY additional advantages: the stronger electronegativity of cyano groups increase the affinity of GDY frameworks to lithium atoms, and the larger atomic volume of methyl groups increases the interlayer distance and provides more storage space and diffusion tunnels.