Sythesis Of Spiropyran Acyl Azid Derivatives And Their Application On The Functionalization Of Multi-walled Carbon Nanotubes

Carbon nanotubes are given a lot of attention because of their outstanding mechanics,thermotics,electronics and optical properties.However,as a result of the lack of functional groups and insolubility caused by their structural,its application is greatly limited,so that modifying the surface of carbon nanotubes by physical or chemical method to introduce functional groups and improve the dispersion of carbon nanotubes is a very hot research topic.As a kind of typical photochromic compounds,spiropyran have very outstanding optical properties.Spiropyran will occur reversible conformational change when light,pH,solvent are changed,so it has great potential applications in optical materials.But now,reports of spiropyran mostly confined to the solution and pure organic system,and make the photochromic properties restricted in the actual application of functional materials.In order to solve this problem,we designed and synthesized spiropyran acyl azide compounds with high reactivity through a simple"one pot reaction" method,used the di-carboxyl group containing spiropyran derivatives as raw materials,which synthesized by Jiamei Wu,who is one of our laboratory members.Then turned the spiropyran acyl azide compound into nitrene structure by high temperature,and connected to the surface of multi-walled carbon nanotubes(MWCNTs)through covalent reaction.This paper conducted a research from the following three aspects:1?The design and synthesis of a new functional acylated nitrogen compound,the spiropyran derivatives contained the acyl azide group.This experimentused the double carboxyl spiropyran as raw material,carbonyl two imidazole as activator,sodium azide as azide reagent,synthesizedl',3',3'-trimethyl-spiro[chromene-2,2'-indoline]-4',6'-diacyl azide(2a),6-methyl-1',3',3'-tri-methyl-spiro[chromene-2,2'-indoline]-4',6'-diacyl zide(2b)and 6-nitro-1',3',3,-trimethyl-spiro[chromene-2,2'-indoline]-4',6,'-diacyl azide(2c)through a "one pot reaction" method in water and N,N-dimethyl formamide mixed solvent,and represented its structure by the nuclear magnetic resonance hydrogen spectrum,infrared spectrum and other means.2?Using we synthesized the spiropyran acyl azide derivatives as monomer,removed nitrogen molecules to form nitrene structure by heating,and then introduced spiropyran derivatives in the surface of multi-walled carbon nanotubes by the conjugate surface modified method.In this paper,we modified the multi-walled carbon nanotubes(MWCNTs)using the synthesized three spiropyran derivatives contained acyl azide group,and obtained the different spiropyran compound modified multi-walled carbon nanotubes.At the same time,we also made analysis through the X-ray photoelectron spectroscopy(XPS),infrared spectra(FTIR),thermo gravimetric analysis(TGA),Raman spectroscopy and transmission electron microscope(TEM),and confirmed the success of tthe multi-walled carbon nanotubes modified by the spiropyran molecular.3?We studied their optical properties by ultraviolet visible absorption spectra.Using spiropyran modified carbon nanotubes kept the optical properties of the spiropyran,and have corresponding excitation peak in solid fluorescence spectrum 420 nm.The uv-visible absorption spectra were higher than the original multi-walled carbon nanotubes in the range of wavelength absorbance.In this paper,the solubility of multi-walled carbon nanotubes have been largely changed after the modification of spiropyran acyl azide compounds.The good dispersion of functionalized multi-wall nanotubes can be observed not only in the organic solvent,but also in aqueous solution.What's more,changing the acidity and alkalinity of the aqueous solution also has a significant effect on the solubility of the modified carbon nanotubes.