The Interface Assembly Of Molecular Aggregate Material And Its Properties

Research on the construction of molecular materials by molecular assembling technology has been tended from the design, assemble and characterization of the structure, photo-/electro- and magnetism- properties of the molecular materials to the design and preparation of functional molecular assembled materials and to the assembly of molecular devices according to the structure, character of one single molecular and the intermolecular interactions. The commonly used molecular interfacial assembly methods include Langmuir-Blodgett (LB), self-assembled monolayers and layer-by-layer assembly techniquesThe thesis was divided into two parts. In the first part, triazines were used to construct molecular assembled materials. Three luminescent 1,3,5-triazine derivatives containing naphthalene or anthracene chromophores were synthesized and used as a film formation materials. Via intramolecular hydrogen bonding of triazines and arachidic acid, monolayers of these triazines were stabilized at the air-water interface. The composition, structure and luminescent behaviors of the organized thin films have been investigated. Surface pressure-area isotherms indicated that the pure triazines were difficult to form stable monolayers, while their mixtures with arachicacid could be stabilized at the air-water interface and then to deposit on substrate surface by the LB method. Phase separation occurred during monolayer compression of the triazines with naphthalene substituents, but not of the triazines with anthracene substituents. These may due to the size of the substituents. Because of the phase transition, there were two kinds of aggregates for the triazines with naphthalene substituents in the LB films and two fluorescence lifetimes were measured for the LB films. It was revealed that the closely packed arrangement for the triazines in the LB films had stronger effect on the excited state than that on the ground one. These organized thin films may act as alternative optical materials.In the second part of the present work, porphyrin derivatives have excellent photonic and electronic properties which have been widely used as photosensitizers. Porphyrins are in form of aggregates that are ubiquitous in nature. The design and construction of novel multiporphyrin arrays to prepare molecular assembled materials and molecular devices continues to be an active research area. Water-soluble zinc tetra-N-methyl-4-pyridinium porphyrin (ZnTMPyP) was coordinated with poly (4-vinylpyridine) (PVP) to form two kinds of polymeric derivatives (ZnTMPyP-PVP) based on the axial coordinative bond between central Zn(II) ions and the pyridyl substituents of PVP. With different content of porphyrin, one of the as-prepared compounds was water-soluble but another one was not. Via noncovalent bond, molecular assembled materials of the as-prepared compounds were constructed at gas-liquid interface and solid-liquid interface. The composition, structure and luminescent behaviors of monolayers, LB films and layer-by-layer assembly films were investigated. Surface pressure-area isotherms indicated that the as-prepared compounds could form stable monolayers when the subphase containing B(C6H5)-which were then deposited on substrate surface by the LB method. Layer-by-layer assembly of the as-prepared compound (ZnTMPyP-PVP) and PdCl2- (as connectors) were performed at solid-liquid interface. In LB films, porphyrin macrocycles were closely packed with a stronger intermolecularπ-πinteraction. In layer-by-layer multilayers, PdCl2- was interacted with PVP via coordination bond, the linked porphyrin macrocycles were not so closely packed as that in LB films. Both LB and LBL films showed well luminescent performance and may act as photosensitizers materials.