Zeolite photochemistry : Investigation of cation-π interaction and diffusion of guest species

沸石光化学：阳离子-π相互作用和客体物质扩散的研究

基本信息

批准号：
14550796
负责人：
HASHIMOTO Shuichi
金额：
$ 2.37万
依托单位：
Gunma National College of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

1. A kinetic study on energy transfer between guest aromatic species and rare earth charge-compensating cations within zeolites :The real-time observation is made of energy transfer (ET) between guest aromatic species, benzophenone and naphthalene, and a rare-earth charge compensating cation, Tb^<3+> within a faujasite zeolite Y by the measurement of a time-dependent rise and decay of emission from the ^5D_4 excited-state of Tb^<3+> on excitation of the guest molecules with a pulsed-laser light. Confinement of the guest species within the cages leads to a greatly enhanced emission intensity relative to solution systems, thus facilitating the ET by enforcing the formation of excited-state complexes. Besides, the kinetic behavior of the emission reveals that while benzophenone molecules are immobilized at the protonic sites within the cages, naphthalene molecules are still mobile leading to a remarkable observation of the loading-dependent rise and decay of the Tb^<3+> emission. Consiste … More nt with the assumption of the excited-state complex, a direct excitation of the absorption band of ^7F_6→^5D_4 band (488 nm) of Tb^<3+> results in a single-exponential emission decay with a lifetime of 2.4 ms both in the absence and in the presence of benzophenone or naphthalene.2. Visual and spectroscopic demonstration of intercrystalline migration and resultant photochemical reactions of aromatic molecules adsorbed in zeolites :We applied a fluorescence microscopic method to investigate the intercrystalline migration of aromatic molecules adsorbed in faujasite zeolites. Photophysical processes such as intersystem crossing and energy transfer assisted by particular charge compensating cations, and photochemical reactions such as charge transfer (CT) and triplet-triplet energy transfer between guest species incorporated in the zeolites were exploited as indicator reactions to afford luminescence color characteristic to an individual zeolite particle. Two types of migration mechanism were evidenced assisted by sample heating at temperatures between 60 and 120℃ : a through space diffusional transfer mode between separated zeolite crystals and a molecular injection process from a loaded crystal to another unloaded crystal, both in contact. A preferential direction of guest migration was found to exist for a few cases : for instance, aromatics such as naphthalene, phenanthrene and chrysene migrate from sodium form of zeolite X (Na^+-X) to thallium-exchanged zeolite X (Tl^+-X). On the other hand, the migration-assisted formation of CT complexes between electron-donating arenes such as phenanthrene and chrysene, and electron-accepting 1,2,4,5-tetracyanobenzene, both incorporated into separate zeolite Na^+-X crystals, takes place as a result of the migration of the donors. Less

1。一项关于客人芳香物种与稀土电荷补偿阳离子之间能量转移的动力学研究：实时观察是由宾客芳香族物种，苯甲酮和萘之间的能量传递（ET）制成^5d_4 TB ^<3+>的激发态在用脉冲激光的访问分子兴奋时。笼子内客人物种的限制导致相对于溶液系统的发射强度极大增强，从而通过强制实施激发态复合物的形成来支持ET。此外，排放的动力学行为表明，虽然苯甲酮分子在笼子内的质子部位固定在固定位置，但萘分子仍然是流动的，导致对载荷依赖性依赖性的上升和TB^<3+>发射的衰减的显着观察。一致……更nt的假设是兴奋状态复合体的假设，这是^7f_6→^5d_4的抽象带（488 nm）TB^<3+>的刺激，从而导致单指数的排放衰减，其生命周期为2.4 ms，均为苯甲酸苯甲酮或苯乙烯烯。在沸石中吸附的芳族分子的晶体间迁移和产生的光化学反应的视觉和光谱证明：我们应用了一种荧光微观方法来研究芳族分子的芳族分子的晶体迁移。特定电荷补偿阳离子的辅助辅助的光物理过程，例如乘以特定的电荷补偿阳离子的辅助，例如电荷转移（CT）和三胞胎 - 三曲线 - 三个曲线 - 沸石中掺入的宾客物种之间的能量转移，作为指示反应，以获得与单个Zeololite粒子的发光颜色的指示反应。在60至120℃之间的温度下，样品加热可以证明两种类型的迁移机制：通过分离的沸石晶体与从负载晶体到另一个卸载晶体的分子注射过程之间的贯穿空间差分转移模式。在几种情况下，发现存在宾客迁移的首选方向：例如，芳香族，苯鞭毛和金烯等芳香剂从沸石X（Na^+-x）迁移到tohallium-exchanged zeolite x（tl^+-x）。另一方面，诸如苯拥素和克赖烯之类的电子散谱之间的CT复合物的迁移辅助形成，以及电子受到1,2,4,5-四苯乙烯的迁移，都融合到了单独的Zeolite Na^+ - X晶体中，是由供体的迁移而成的。