Interface Group Assembly Of Polymer Molecules Aggregate Material And Its Optical And Electrical Properties

Coordination polymers which were constructed with metal ions as connectors and ligands as linkers,first named in 1960s,have attracted growing attention because of their unique structure and properties.In addition to the nature of metals and ligands, there are some unique functions owing to the porous structure,such as luminescence, catalysis and so on.The Interfacial assembly technology has the following advantages: (1) The monolayers of coordination polymers were prepared by an interfacial coordination reaction between ligands and sub-phase ion are a specific supramolecular structure,and are contrallable.The compounds on the interface flows well,and are easy to obtain chemical equilibrium.(2) The monolayers were deposited onto substrate surfaces by the Langmuir-Blodgett(LB) method.The substrate surfaces can be washed to remove unreacted material without the complex purification and separation.(3) The electrochemical properties of coordination polymers can be easily detected with ITO electrode modified by the polymers.In the present work,metal-multiporphyrins and metal-Bisterpy polymers were designed and assembled at air-liquid interface.Besides the electrochemistry,redox and spectroscopic studies of the two polymers,we reported spectroscopic studies of pyterpy and its metal complexes in methanol solution.This paper was divided into three major parts by different ligands.1.Monolayers of the manganese(â…¢) tetrapyridylporphyrin(MnTPyP) and its metal-mediated multiporphyrin arrays were formed at the air-water interface.These monolayers were deposited onto substrate surfaces by using the Langmuir-Blodgett (LB) method.Compositions and structural features for the LB films of MnTPyP multiporphyrin arrays were characterized by using the UV-vis absorption, transmission electron microscope(TEM) and X-ray photoelectron spectroscopy (XPS).Reversible Mn(â…¡)TPyP(?) Mn(â…¢)TPyP and Mn(â…¢)TPyP(?) Mn(â…£)TPyP redox waves were recorded for the indium tin oxide(ITO) electrodes modified by the LB films.The electrodes modified with the multiporphyrin arrays showed catalytic oxidation properties for nitrite when the cyclic voltammeter measurements were done in an electrolyte solution of sodium nitrite.Spectroelectrochemical results revealed a reversible redox process between Pd-Mn(â…¢)TPyP and its Mn(â…£)-oxo species but an irreversible process between Pd-Mn(â…¢)TPyP and its Mn(â…¤)-oxo species.These well-organized multiporphyrin arrays are potential molecular materials in the studies of nature and artificial catalytic processes as well as in the development of redox-based molecular switches.2.Viologen-like ligand,2,2':4',4"-terpyridinium,",1""-[1,4-phenylenebis(methy-lene)] bis[6'-(2-pyridinyl)bis[hexafluorophosphate1-)](Bisterpy),were synthesized according to literature methods and characterized by ¹HNMR and element analysis. Monolayers of Metal-Bisterpy coordination polymeric hybrids could be stabilized on the subphase surfaces containing small amount of anionic polyelectrolyte of poly(styrenesulfonic acid-o-maleic) Sodium(PSS) and inorganic salts.The polymers were transferred onto substrate surfaces by using the LB method.The prepared LB films of M-Bisterpy coordination polymers were characterized by using UV-vis absorption,fluorescence and X-ray photoelectron spectra(XPS).Cyclic voltammogram studies revealed two couples of quasi-reversible redox waves corresponding to two electron processes of ligand both in solutions and in LB films. Some immobilized films of the coordination polymers showed well electrochromic response upon an applied potential of-1.1 V vs Ag/AgCl.Thus,the organized thin films of Bisterpy and its metal-mediated coordination polymers could be developed as molecular materials for redox-based molecular switches and display devices.3.The luminescent properties of the ligand pyterpy and its metalated(Zn²⁺,Fe²⁺, Co²⁺,Sm³⁺,Eu³⁺ and Tb³⁺) complexes in the methanol solutions were investigated. The ligand could give off 360 nm light under UV radiation.In solution,this ligand emission increased with its concentrations when the concentrations were below 1.3×10₅ mol/1;contrarily,the emission was quickly decreased due to the concentration quenching effects and the addition of the electroactive metal ions like Fe²⁺ and Co²⁺;however,the luminescence was almost unchanged when the Zn²⁺ ion was added to the ligand solution.The excited energy of the ligand could transfer to some lanthanide ions,especially Tb³⁺,resulting in strong Tb³⁺ luminescence emission.