取代基对卟啉分子自组装聚集体纳米结构的调节

Tuning the Morphology of Self-Assembled Nanostructures of Porphyrin Molecules by Varied Meso-Substituents

运用简单的"one-step"法自组装技术,将Meso位具有不同取代基团的卟啉分子Meso-5,10,15,20-四(对甲氧基苯基)卟啉(Ⅰ),Meso-5,10,15,20-四苯基卟啉(Ⅱ)和Meso-5,10,15,20-四(对氯苯基)卟啉(Ⅲ)组装成有机纳米聚集体。利用多种表征手段系统研究化合物(Ⅰ),(Ⅱ)和(Ⅲ)在水溶液中的自组装性质。结果表明,在自组装过程中,3种卟啉分子均形成J型聚集体,从化合物(Ⅰ),(Ⅱ)到(Ⅲ),随着卟啉Meso位取代基供电子能力依次下降,分子间相互作用程度减弱,其纳米聚集体形貌由二维四方片状逐渐变成一维纳米带。这表明通过调节卟啉Meso位取代基的供/吸电子能力,可以调节分子间非共价键相互作用程度,从而控制卟啉分子自组装纳米结构的形貌。

Metal free tetrakis （4-methoxylphenyl） porphyrin （ Ⅰ ）, tetra （phenyl） porphyrin （Ⅱ ） and tetrakis （4-chlorophenyl） por- phyrin （ Ⅲ ） were assembled into organic nanostructures by ＂one-step＂ method. Their self-assembly properties, especially the effect of meso-substituents with varied electron-donating/withdrawing properties on tuning and controlling the morphology of self-assembled nano- structures of these porphyrin derivatives, have been comparatively studied by electronic absorption, transmission electronic microscopy （TEM） ,and X-ray diffraction（XRD） techniques. J-type aggregates have been formed with the increasing degree of intermolecular inter- action （ Ⅲ ） 〈 （ Ⅱ ） 〈 （ Ⅰ ）, which are in agreement with the degree of electron-donating and electron-with＆awing properties of meso- substituents. TEM observation suggests that the microcrystal structure is dependent on the degree of intermolecular interaction resulting from varied meso-substituents of these porphyrin derivatives. Square and lamellar, nanorods as well as nanobelts structures have been obtained in aggregates of porphyrin （ Ⅰ ）, （Ⅱ ）, （Ⅲ） ,respectively. Favorable growing direction of microstructures in these aggregates is different in the self-assembly process, which in turn result in different morphology for the self-assembled nanostructures.