羧脒盐桥介导的单重态能量传递直接观察

设计构建了以羧脒盐桥联接的萘和蒽超分子组装体系,NA-(脒基-羧基)-An以及相应的模型体系.稳态和时间分辨荧光光谱研究表明,置于羧脒盐桥两端的萘和蒽基团之间发生了从萘到蒽的单重态能量传递,NA-(脒-羧)-An超分子体系中单重态能量传递效率和速率常数分别大于0.99和9.9×10⁹s^-1.推测羧脒盐桥介导了体系中的单重态能量传递过程,单重态能量传递‘通过键’以电子交换机制进行.     

冠醚连接的给体-受体化合物中分子内远程三重态能量传递

本文合成了用冠醚连接的二苯酮基(给体)和萘基(受体)的二元化合物,用稳态和时间分辨光谱研究了该化合物分子内远程三重态能量传递,证实当冠醚络合钠离子以后,可以发生有效的分子内远程三重态能量传递,对传递机制进行了讨论。     

4,4’-二氯二苯酮合成二氮杂萘联苯酮结构聚醚砜酮的研究

以4-(4-羟基苯基)*2,3-二氮杂萘-1-酮(DHPZ)、4,4’-二氯二苯砜(DCS)和4,4’-二氯二苯酮(DCK)为原料,采用分步加料的方法,合成了系列高分子量的聚芳醚砜酮共聚物(PPESKs),其特性黏度在0.40 ～0.61dL/g之间,解决了由于DCK活性低不适合用于聚芳醚合成的问题.采用FTIR、示差...     

高分子三线态敏化剂分子中能量迁移的研究 I. 聚(乙烯基二苯酮-β-乙烯基萘)中的能量迁移的研究

本工作对乙烯基二苯酮-β-乙烯基萘共聚物体系分子内的能量迁移和转移进行了研究,在77K玻璃态溶液中,不论以310nm或以370nm波长激发时,共聚物都发生强的萘光,各共聚物三线态能量转移量子效率φET^T^-^T大于80%,表明此高分子体系能有效地进行三线态能量迁移和转移。     

9—羟基苯并萘酮的结构和激发态质子转移过程

用INDO系列方法对9-羟基苯并萘酮的结构和激发态质子转移过程进行了理论研究,求得基态和激发态反应的位能面、势垒和过渡态,对反应机理进行了探讨。     

通过异喹啉盐与环状1,3-二酮一锅合成二氢异喹啉-3-酮-1,4-桥环结构

异喹啉盐具有两个亲电位点, 用它与双亲核试剂发生去芳构化/环化反应, 是高效构建异喹啉桥环结构的有效策略. 然而, 这一策略主要集中在1,3-桥环结构的合成. 最近利用异喹啉盐与4-羟基香豆素反应, 首次实现了二氢异喹 啉-3-酮-1,4-桥环的合成. 但是, 当用环状1,3-二酮代替4-羟基香豆素反应时, 意外地得到了异喹啉-1,3,4(2H)-三酮. 利用高分辨质谱分析发现, 这一意外转化是由于环状1,3-二酮发生O-亲核取代后, 消除2-溴-1,3-环状二酮, 得到4-溴异喹啉-3(2H)-酮. 该中间体发生两次连续水解/空气氧化后, 得到了异喹啉-1,3,4(2H)-三酮. 基于此机理的认识, 向反应体系中添加催化量的三氟甲烷磺酸后, 成功抑制了环状1,3-二酮的O-亲核取代反应, 顺利得到了二氢异喹啉-3-酮的1,4-桥环结构(33个反应实例). 反应条件温和, 提供了一种构建异喹啉1,4-桥环骨架的高效合成方法.     

含萘环结构的聚醚酮醚酮酮的合成与表征

二苯酮;含萘环结构的聚醚酮醚酮酮的合成与表征     

对二甲胺基二苯酮 /碘鎓盐体系敏化甲基丙烯酸甲酯光聚合

研究了二甲胺基二苯酮 (DMABP) /氯化二苯基碘盐 (DPIOC)组成的光敏引发体系引发的甲基丙烯酸甲酯光聚合 ,发现该体系也是一个有效的自由基型光引发体系。通过动力学研究得到了该引发甲基丙烯酸甲酯光聚合的动力学方程 ,并对引发机理做了探讨。     

聚醚酮醚酮酮/含萘环聚醚酮醚酮酮无规共聚物的合成与性能

在无水AlCl3及N－甲基吡咯烷酮（NMP）存在下，以4,4′-二（α－萘氧基）二苯酮（DNBP）作为第三单体，将其与4，4′－二苯氧基二苯酮（DPBP）和对苯二甲酰氯（TPC）在1，2－二氯乙烷（DCE）中进行低温溶液共缩聚反应，合成了一系列聚醚酮醚酮酮／含萘环聚醚酮酮醚酮酮无规共聚物，用IR、DSC、TG及WAXD等方法对其结构和性能进行了表征与测试。研究结果表明共聚物的玻璃化转变温度（Tg)要比纯PEKEKK的高，而其熔融温度（Tm)和结晶度（Xc)则随共聚物中含萘环PEKEKK结构单元含量的增加而逐渐降低。共聚物具有优异的耐热性能及抗腐蚀性能。     

蒽-对二氰基乙烯基苯激基复合物的形成与能量传递

本文设计合成了三个以不同链长相连接的蒽-对二氰基乙烯基苯(An-DCVB)化合物。利用吸收光谱,荧光光谱,激光闪光光解和单光子计数器等证实An-DCVB受光激发,发生分子内电子转移,生成激基复合物且发现有三重态能量传递,描述了分子内电子转移的主要途径,研究并探讨了An-DCVB的三种不同连接链长对分子构象,激基复合物的形成以及三重态能量传递的影响。     

Fluorescent Supramolecular Organic Frameworks Constructed by Amidinium-Carboxylate Salt Bridges

We report here a set of fluorescent supramolecular organic frameworks (SOFs) that incorporate aggregation-induced emission (AIE) units within their frameworks. The fluorescent SOFs of this study were constructed by linking the tetraphenylethylene (TPE)-based tetra(amidinium) cation TPE⁴⁺ and aromatic dicarboxylate anions through amidinium-carboxylate salt bridges. The resulting self-assembled structures are characterized by fluorescence quantum yields in the range of 4.6∼14 %. This emissive behavior is ascribed to a combination of electrostatic interactions and hydrogen bonds that operate in concert to impede motions that would otherwise lead to excited state energy dissipation. Single-crystal X-ray diffraction analyses revealed that the length of the dicarboxylate anion bridges has a considerable impact on the structural features of the resulting frameworks. Nevertheless, all SOFs prepared in the context of the present study were found to display emissive features characteristic of TPE-based AIE luminogens with only a modest dependence on the structural specifics being seen. The SOFs reported here could be reversibly “broken up” and “reformed” in response to acid/base stimuli. This reversible structural behavior is consistent with their SOF nature.     

卟啉-噁二唑二元体系光诱导能量及电子传递研究

以5-对氨基苯基-10,15,20-三苯基卟啉及2-苯基-5-(对氨基苯基)-1,3,4-噁二唑为原料合成了系列卟啉-噁二唑二元化合物, 其结构通过¹H NMR, ESI-MS, IR, UV-Vis确定. 对合成化合物进行光谱性能测定, 结果表明, 在卟啉与噁二唑混合体系中, 存在着卟啉激发态分子向噁二唑基态分子的分子间电子传递过程, 导致卟啉激发态的荧光猝灭; 在卟啉-噁二唑二元体系中, 315 nm激发下发生了由激发态噁二唑基团至卟啉基团的能量传递, 导致噁二唑基团荧光猝灭, 卟啉基团荧光增强. 420 nm激发下不存在分子内卟啉基团向噁二唑基团的电子回传竞争; 电化学性能测定进一步表明从噁二唑基团向卟啉基团的电子传递是可能的. 因此卟啉-噁二唑二元化合物可能作为一种模型, 模拟光合作用中电子给体至叶绿素之间的电子传递过程.     

Hamilton受体与萘之间光诱导电子转移和三重态能量传递研究

将两个2,6-二氨基吡啶衍生物与异酞酸相连, 得到一个袋状巴比妥酸衍生物受体(Hamilton受体, H-receptor), 同时合成了带有萘基团的巴比妥酸衍生物(G-Np), 两者在非极性溶剂中形成氢键体系, 二氯甲烷溶剂中表观结合常数KAPP＝(4.9±0.5)×104 mol－1•L. 稳态荧光发射光谱和磷光发射光谱研究表明, 室温下H-receptor和G-Np之间主要发生单重态电子转移过程, 77 K下, H-receptor与G-Np之间发生三重态能量传递过程. 本研究为Hamilton氢键体系的理论研究提供了一个新的模型, 对理解氢键在生命体系中的作用有重要的意义.     

2-脲基-4[1氢]-嘧啶酮四氢键萘-蒽超分子组装体系:"通过键"机制的单重态能量传递

设计合成了基于2-脉基-4[1氢]-嘧啶酮AADD四氢键萘-葱超分子组装体系UPNa·UPAn.稳态和时间分辨荧光光谱研究表明UPNa·UPAn四氢键组装体可以发生从茶到葱的高效、快速的单重态能量传递过程.体系内光诱导单重态能量传递的速度和效率远大于通过F(o)rster机制的单重态能量传递速率,表明组装体系UPNa·...     

Role of the Bridge in Photoinduced Electron Transfer in Porphyrin–Fullerene Dyads

The role of π‐conjugated molecular bridges in through‐space and through‐bond electron transfer is studied by comparing two porphyrin–fullerene donor–acceptor (D–A) dyads. One dyad, ZnP–Ph–C₆₀ (ZnP=zinc porphyrin), incorporates a phenyl bridge between D and A and behaves very similarly to analogous dyads studied previously. The second dyad, ZnP–EDOTV–C₆₀, introduces an additional 3,4‐ethylenedioxythienylvinylene (EDOTV) unit into the conjugated bridge, which increases the distance between D and A, but, at the same time, provides increased electronic communication between them. Two essential outcomes that result from the introduction of the EDOTV unit in the bridge are as follows: 1) faster charge recombination, which indicates enhanced electronic coupling between the charge‐separated and ground electronic states; and 2) the disappearance of the intramolecular exciplex, which mediates photoinduced charge separation in the ZnP–Ph–C₆₀ dyad. The latter can be interpreted as a gradual decrease in electronic coupling between locally excited singlet states of D and A when introducing the EDOTV unit into the D–A bridge.     

Remote Sensitized Photoisomerization via Through‐Bond Triplet–Triplet Energy Transfer Mediated by a Salt Bridge in a Supramolecular Dyad

A supramolecular dyad, BP‐(amidinium‐carboxylate)‐NBD is constructed, in which benzophenone (BP) and norbornadiene (NBD) are connected via an amidinium‐carboxylate salt bridge. The photophysical and photochemical properties of the assembled BP‐(amidinium‐carboxylate)‐NBD dyad are examined. The phosphorescence of the BP chromophore is efficiently quenched by the NBD group in BP‐(amidinium‐carboxylate)‐NBD via the salt bridge. Time‐resolved spectroscopy measurements indicate that the lifetime of the BP triplet state in BP‐(amidinium‐carboxylate)‐NBD is shortened due to the quenching by the NBD group. Selective excitation of the BP chromophore results in isomerization of the NBD group to quadricyclane (QC). All of these observations suggest that the triplet–triplet energy transfer occurs efficiently in the BP‐(amidinium‐carboxylate)‐NBD salt bridge system. The triplet–triplet energy transfer process proceeds with efficiencies of approximately 0.87, 0.98 and the rate constants 1.8×10³ s^?1, and 1.3×10⁷ s^?1 at 77 K and room temperature, respectively. The mechanism for the triplet–triplet energy transfer is proposed to proceed via a “through‐bond” electron exchange process, and the non‐covalent bonds amidinium‐carboxylate salt bridge can mediate the triplet–triplet energy transfer process effectively for photochemical conversion.     

Photoinduced Electron and Energy Transfer in Dyads of Porphyrin Dimer and Perylene Tetracarboxylic Diimide

Two compounds containing a porphyrin dimer and a perylene tetracarboxylic diimide (PDI) linked by phenyl ( 1 ) or ethylene groups ( 2 ) are prepared. The photophysical properties of these two compounds are investigated by steady state electronic absorption and fluorescence spectra and lifetime measurements. The ground state absorption spectra reveal intense interactions between the porphyrin units within the porphyrin dimer, but no interactions between the porphyirn dimer and PDI. The fluorescence spectra suggest efficient energy transfer from PDI to porphyrin accompanied by less efficient electron transfer from porphyrin to PDI. The energy transfer is not affected by the dimeric structure of porphyrin or the linkage between the porphyrin dimer and PDI. However, the electron transfer from porphyrin to PDI is significantly affected by either the linkage between the donor and the acceptor or the polarity of the solvents. The dimeric structure of the porphyrin units in these compounds significantly promotes electron transfer in nonpolar, but not in polar solvents.