Nanoscale Assembly And Structure Of Supramolecular Aggregates Of Porphyrinato/Phthalocyaninato Complexes

Owing to the unique optical, electrical, and properties, associated with the intriguing intramolecularÏ€-Ï€interactions, porphyrins, phthalocyanines, as well as sandwich type rare complexes, as a novel functional materials, have been expected to be widely potential application in materials science, such as in molecular electronics, molecular information storage, and nonlinear optics, etc. Recently, it is significantly interested in ordered supramolecular aggregate and nanoscale assembly fields. In order to extensively investigate supramolecular aggregation behaviors and supramolecular assembly methodology of porphyrinato and/or phthalocyninato complexes, in this thesis a series of porphyrin and/or phthalocyanine derivatives are selected, and some modern measuring techniques were performed to examine their aggregate structures, morphologes and nanostructures. Furthermore, the monolayer of supramolecular aggregate have been used as a good template to induce the ordered orientation and hollow nanostructures of inorganic nanomaterials. The major contents are as follows,1. The supramolecular aggregates of (porphyrinato)/(phthalocyaninato) complexes fabricated at the air/liquid interface(1) It has been investigated that the temperature dependent aggregation behaviors and structures of the Langmuir monolayers ofα-substituted phthalocyaninato nickle complexes {Ni[Pc(α-OC₇H₁₅)] (1),Ni[Pc(α-OC₅H₁₁) (2),Ni[Pc(α-OC₁₀H₇)]] (3) were formed at the air/water interface. The orderedly supramolecular system has been assembled by LB technique. In this part, the key research work is that the monolayer morphologes of Ni[Pc(α-OC₇H₁₅)] (1) have transformed from nanorings to nanocrystals by changing the temperature of the subphase, as well as the optical properties were changed along with the different aggregates. Compound (1) formed nanoring structures with the outer diameter of 70-150 nm and inner diameter of 50 nm at 25.0℃while 2 and 3 formed spherical particles. This difference can be ascribed to the different substituents atα-position. The morphologies of the (1) aggregates in monolayers have been found to be temperature dependent. The formation of regular quadrate crystals was induced by decreasing in temperature. UV-vis absorption spectra have revealed strong intermolecular interactions in the nanoring aggregates. Polarized UV-vis absorption spectra suggest a titled orientation with respect to the surface of substrate for phthalocyanine macrocycles in the nanoring aggregates. The properties of the supramolecular assembly of phthalocynines can be tuned by changing the substitutents and varying the experimental conditions. This is very useful in the construction of optical electronic devices.(2) Because the aggregation behaviors were intensively influenced by different subphases, the mixed (porphyrinato) (phthalocyaninato) double- and triple-decker rare complexes have been designed in order to systematically investigate the aggregation behaviors by changing the subphase conditions:(i) The subphase tuned by the pH. The double-decker [Ce(Pc)(TPyP)] aggregation behaviors at the air/water interface were changed along with the different pH of the subphase, due to the interactions between the H⁺ cations from the subphase and the pyridyl substituent attached the double decker molecule. Therefore, the aggregation behaviors of the double-decker molecule at the interface were controlled by tuning the pH of the subphase method. The experimental results demonstrated that the different aggregates were fabricated at the various pH value of the subphase while keeping the same reaction time.(ii) CdCl₂ aqueous solution used as the subphase. The sandwich-type mixed porphyrinato/phthalocyanato rare triple-/double- deckers, [Eu₂(Pc)₂(TPyP)] (a), [Sm₂(Pc)(TPyP)₂] (b) and [Ce(Pc)(TPyP)] (c) were selected to investigate systematically the aggregation behaviors at the interfaces of air/pure water and air/ CdCl₂ subphase. As a result, the stable monolayers have all been fabricated and demonstrated different aggregation behaviors at the two kinds of interfaces, owing to the coordination interaction between the sandwich type complex and the Cd²⁺ cations from the subphase.2. According to the research results mentioned above, the sandwich (phthalocyaninato) [tetrakis(4-pyridyl)porphryrinato] rare triple-/double- decker complexes were fabricated the stable network monolayers at the air/CdCl₂ interface which could be used as a good template to induce the growth of the well defined nanostructures containing cadmium element. Therefore, highly ordered nanorods of CdCl₂·H₂O orientated on the monolayer surface were found to grow along with the water evaporating. Highly ordered nanorods of CdCl₂·H₂O were found to grow on the Langmuir film surface of. The CdCl₂·H₂O nanorods formed were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and X-ray photoelectron spectroscopy (XPS). By contrast experiment, it was indicated that the the Langmuir monolayer of sandwich complexes played an effective template role in forming well orientated CdCl₂·H₂O nanorods. Furthermore, the formation mechanism of the nanostructures was discussed in this part. The method described here offers a new route for the design and preparation of highly ordered inorganic nanomaterials.3. Regular square, wirelike, quadrate, and rodlike nanocrystal arrays of Cd²⁺-, Hg²⁺, or Ag⁺ metal cation-mediated sandwich-type mixed (phthalocyaninato) [5,10,15,20-tetrakis(4-pyridyl)poprhyrinato] cerium (III) double-decker complex [Ce(Pc)(TPyP)] have been successfully prepared at the water-chloroform interface. The nanocrystal growth processes were monitored by the transmission electron microscopy (TEM), which reveals that different morphologies of nanocrystals have been fabricated from double-decker molecules connected by different kinds of metal cations as connectors, forming coordination polymers. These nano-scaled coordination polymers were characterized by FT-IR spectra and energy-depressive X-ray spectra (EDS). EDS results have clearly showed the elements from the nanocrystals and FT-IR spectra have further verified that the coordination interaction occurred between the double decker complex and metal cations. Various morphologies of well-defined nanocrystals were formed depending on the varieties and concentration of metal cations, revealing that the geometries and the coordination mode of corresponding metal ions dominate the framework of coordination polymer nanocrystals formed. Furthermore, the possible supramolecular interaction modes of the different morphology nanostructures were proposed. UV-vis absorption spectrum indicates J-aggregates of the double decker molecules formed in nanofiber polymer films mediated by Hg²⁺ cation, compared with the chloroform solution, but not the same as monomeric H₂TPyP nanocrystal films. These novel nanocrystals obtained are expected to be useful in the field of nano-electronics.4. Owing to the unique properties of the sandwich type rare complexes, it is a necessary step forward the miniature of instruments that this kind of materials should be prepared the corresponding nanostructures. Nanotubes of sandwich-type mixed (porphyrinato)(phthalocyaninato) europium(III) double-decker,H{Eu(TClPP)[Pc(α-OC₄H₉)₈]} were fabricated by using nanoporous anodized aluminum oxide (AAO) membrane as the template. The tubular structure was investigated by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), and UV-vis spectroscopy. It has been found that the outer diameter of the nanotubes was matched with the pore diameter of AAO membrane very well. HRTEM micrographs reveal that the walls of the nanotubes have orderly layered structure and the space between the adjacent layers is 0.58 ran, which agrees well with the size (thickness) of one double-decker molecule, indicating that the nanotubes are supramolecules formed from the double-decker molecules due toÏ€-Ï€interactions between the macrocycles. UV-vis absorption spectrum of the nanotubes showed the formation of J-aggregates of the complex molecules, consisting with HRTEM investigation result. Owing to the rich optical and electrochemical properties as well as special electronic structure of sandwich porphryinato and / or phthalocyaninato rare earth complexes, nanotubes obtained are expected to be useful in the field of nano-electronics.