STUDY ON SPECIFIC INTERACTION AND PHOTOFUNCTIONALITY OF STABLE RADICALS FORMED BY PHOTOINDUCED ELECTRON TRANSFER REACTION

1)制备了具有硝基、二氰乙烯基等强吸电子基团的苯基吡啶离子四苯基盐。它们在1,2-二甲氧基乙烷（DME）等极性较低的有机溶剂中形成离子对电荷转移（IPCT）配合物。在脱气条件下激发IPCT带，发生电子转移反应，形成在可见光区有吸收光谱的苯乙烯基吡啶基自由基。同时，在近红外区观察到较宽的吸收光谱，由于光生成的苯基吡啶基自由基与母体苯基吡啶阳离子之间的电子相互作用，该吸收光谱被分配到电荷共振（CR）带。cr波段光谱与取代基有关，硝基衍生物的稳定能略高于二氰乙烯基衍生物。2)二氰乙烯基衍生物中光诱导自由基的电子自旋共振（ESR）谱是一条宽单线谱。将其与未辐照的二氰乙烯基衍生物二甲醚溶液混合后出现超精细结构，其归属于光生成的苯基吡啶基自由基与母体苯基吡啶离子相互作用形成的二聚体自由基。3)利用纳秒脉冲激光对这些盐进行了动力学研究。cr波段吸收在ns脉冲内上升，与苯乙烯基吡啶基自由基的可见吸收方式相似，强烈提示二聚体自由基阳离子的扩散形成。4)两亲性四苯基硼酸硝基苯基吡啶与花生四烯酸的混合物在空气-水界面处呈现固体凝聚相。y型Langmuir-Blodgett薄膜沉积在石英板上，沉积率为统一。采用蒸发法制备微晶膜。在与溶液相同的条件下，这些固体薄膜的光激发引起了一些光谱变化。然而，不可能在这些固体薄膜中观察到苯基吡啶基自由基和二聚体自由基阳离子的形成。少

1) Tetraphenyl salts of styrylpyridinium ions with strong electron-withdrawing groups such as nitro and dicyanovinyl groups were prepared.They formed ion-pair charge-transfer (IPCT) complexes in less polar organic solvents like 1,2-dimethoxyethane (DME).Upon excitation of an IPCT band in degassed conditions, electron transfer reaction occurred resulting in the formation of styrylpyridinyl radical with an absorption spectrum in the visible region. At the same time a broad absorption spectrum was observed in the near infrared region, which was assigned to the charge-resonance (CR) band due to the electronic interaction between a photogenerated styrylpyridinyl radical with a parent styrylpyridinium cation. The CR-band spectrum depended on the substituents and the stabilization energy was slightly higher in nitro-derivative than dicyanavinyl-derivative.2) The Electron Spin Resonance (ESR) spectrum of photoinduced radicals in dicyanovinyl-derivative was a broad singlet due to exchange broad … More ening. Hyperfine structure appeared upon mixing it with unirradiated DME solution of dicyanovinyl-derivateve, which was assigned to dimer radical cations formed by interaction of photogenerated styrylpyridinyl radicals with parent styrylpyridinium cations.3) Kinetic studies were made on these salts using a nano-second (ns) pulsed laser. The CR-band absorption rose within a ns pulse in a similar manner as the visible absorption of styrylpyridinyl radicals, strongly suggested diffusionlness formation of dimer radical cations.4) A mixture of amphipathic nitrostyrylpyridinium tetraphenylborate and arachidic acid showed a solid condensed phase at the air-water interface. Y-type Langmuir-Blodgett films were deposited on a quartz plate with deposition ratio of unity. Microcrystalline films were also prepared by evaporation. Photoexcitation of these solid films at the same condition as in solutions caused some spectral chantes. It was, however, not possible to observe the formation of styrylpyridinyl radicals and dimer radical cations in these solid films. Less