Synthesis And Property Of Mono-ester At The Lower Rim Of Azo-calix[4]Arene Derivatives

Calixarenes are a very attractive class of macrocyclic compounds, which is easily modified, their cavity size are adjustable and conformation is variable. The highly selective host molecules can be gained by modification of reaction sites on calix[4]arene. Azocalixarenes are synthesized by introduction of azo unit into calix[4]arene framework through azo-coupling reaction. They can not only presents a variety of colors, but also exhibit good solution and selectivity to metal ion and organic molecules, So they are widely used in biological, industrial, medical, analysis, separation, environmental chemistry, chemical sensors and many other fields.Major works in this paper:series of azo-calix[4]arene derivatives containing monoethoxycarbonylmethoxy unit were designed and synthesized. Their complexation properties with metal ions were studied by UV-visible spectroscopy and fluorescence spectroscopy. The results are as follows:(1)5,1l,17,23-tetra-t-butyl-25,26,27,28-tetrahydroxycalix[4]arene was synthesi-ed from p-tert-butylphenol and formaldehyde.(2)25,26,27,28-tetrahydroxycalix[4]arene were synthesized from5,11,17,23-tetra-t-butyl-25,26,27,28-tetrahydroxycalix[4]arene and aluminium chloride.(3)25-ethoxycarbonylmethoxy-26,27,28-trihydroxycalix[4]arene were synthesi-zed from25,26,27,28-tetrahydroxycalix[4]arene and ethylchloroacetate.A series of azocalix[4]arene derivatives were synthesized:(4)5,11,17-tri(2-nitrophenyl)azo-25-ethoxycarbonylmethoxy-26,27,28-trihydrox ycalix[4]arene;5,11,17-tri(3-nitrophenyl)azo-25-ethoxycarbonylmethoxy-26,27,28-tr ihydroxycalix[4]arene;5,11,17-tri(4-nitrophenyl)azo-25-ethoxycarbonylmethoxy-26,27,28-trihydroxycalix[4]arene;5,11,17-tri(4-methoxyphenyl)azo-25-ethoxycarbonyl methoxy-26,27,28-trihydroxycalix[4]arene;5,11,17-tri(3-methoxyphenyl)azo-25-etho xycarbonylmethoxy-26,27,28-trihydroxycalix[4]arene;5,11,17-tri(4-chlorophenyl)az o-25-ethoxycarbonylmethoxy-26,27,28-trihydroxycalix[4]arene;5,11,17-tri(4-bromo phenyl)azo-25-ethoxycarbonylmethoxy-26,27,28-trihydroxycalix [4] arene; (5)A11the structure of the products were characterized by’H-NMR, IR and MS.(6)The reaction yield of5,11,17-tri(2-nitrophenyl)azo-25-ethoxycarbonyl-methoxy-26,27,28-trihydroxycalix[4]arene was improved by the orthogonal experiment.(7)The recognition of azo-calix[4]arene on metal ions were investigated by UV-visible spectroscopy and. fluorescence spectroscopy. All of the tested azocalix [4] arenes can selective recognition of Na+and K+metal ions better than other ions.