配位键驱动的多卟啉阵列结构在纳米SiO2表面的组装及光电性能

制备了吡啶功能化的纳米二氧化硅(nanoSiO₂BPy), 并利用配位键驱动的层层自组装技术, 以四吡啶基锌卟啉(ZnTPyP)为链接单元, 在nanoSiO₂BPy表面构筑了含有(Pd/ZnTPyP)_n多卟啉阵列结构的有机-无机杂化材料. 利用热重、 紫外-可见吸收光谱和X射线光电子能谱跟踪分析了nanoSiO₂BPy@(Pd/ZnTPyP)_n杂化材料的组装过程. 结果表明, nanoSiO₂BPy@(Pd/ZnTPyP)₃杂化材料在150~450 ℃升温区间内质量损失17%, 可归结为组装在纳米SiO₂表面的多卟啉阵列和少量有机物的热分解. 紫外-可见和荧光光谱表明, 在nanoSiO₂BPy@(Pd/ZnTPyP)_n杂化材料中, 锌卟啉Soret带的吸收峰出现在426 nm处, 其Q带的荧光发射峰出现在605和655 nm处, 荧光寿命约为1.78 ns, 光谱数据均与锌卟啉在稀的二甲亚砜溶液中的结果接近, 表明组装在nanoSiO₂BPy表面的锌卟啉环之间相互作用较弱, 没有形成聚集体. 场发射透射电镜照片显示, 由于Pd/ZnTPyP的组装, nanoSiO₂BPy@(Pd/ZnTPyP)₃杂化材料的平均直径由原料的10~16 nm增加到15~20 nm. 杂化材料修饰电极的循环伏安曲线在-0.6~-2.4 V(vs. Ag/AgCl)范围内出现了2对不可逆的氧化还原峰, 归属于卟啉被氧化的电子转移过程. 探讨了nanoSiO₂BPy@(Pd/ZnTPyP)_n杂化材料作为光敏剂在光电转换、 光催化乙基紫精的还原和显色方面的应用.

Pd(Ⅱ)-Directed Layer-by-layer Assembly of Multiporphyrin Arrays on Silica Nanoparticle Surfaces for Photocurrent Generation and Photochromism of Viologens†

Pyridyl-functionalized silica nanoparticles(nanoSiO2BPy) were prepared, on the surfaces of which the Pd(Ⅱ)-directed multiporphyrin arrays were constructed by using the layer-by-layer( LBL) technique with zinc tetrapyridylporphyrin(ZnTPyP) as multi-dentate linkers to produce the nanoSiO2BPy@(Pd/ZnTPyP)n hybrid material. Thermogravimetric analysis revealed a mass loss of approximately 17％ of the total mass that was attributed to the decomposition of organic species in the nanoSiO2BPy@(Pd/ZnTPyP)3 hybrid. For the ZnTPyP in the hybrids, the Soret absorption band appeared at about 426 nm, the fluorescent emission bands appeared at about 605 and 655 nm, and the emission lifetime was approximately 1. 78 ns. All these data were much similar to those of ZnTPyP in the dilute DMSO solutions, suggesting that the porphyrin-porphyrin inter-actions were weak and no porphyrin aggregates formed in the hybrid. The silica nanoparticle sizes slightly in-creased from 10—16 nm to 15—20 nm, which was attributed to the fact that the multiporphyrin arrays were immobilized on the particle surfaces. Cyclic voltammograms of the hybrid in the casting films revealed two cou-ples of redox peaks in the potential range of -0. 6—-2. 4 V(vs. Ag/AgCl), corresponding to the electron transfer processes of porphyrin oxidation. Finally, the indium tin oxide electrodes covered with the nanoSiO2BPy@(Pd/ZnTPyP)3 hybrid were used as the photosensitizers for the light-induced current genera-tion and photochromism of ethyl viologens.