Synthesis and extraction properties of multifunctionalized azocalix[4]arenes containing bipyridyl subunits

Abstract

A series of four azocalixarene derivatives bearing bipyridyl units and additional functional groups such as amide, ester and pyridine at the phenolic oxygen atoms were synthesized. The conformational properties of these ligands were obtained by 1 H NMR spectroscopy. Moreover, extraction properties towards different metals of 1, 2, 4, 5 and 6 using liquid-liquid extraction by atomic absorption spectrometry have been studied and exhibit Ag 1 selectivity.Scheme 1 Synthetic pathway of hetero-functionalized azocalix[4]arene incorporating both bipyridyl and pyridyl groups 2.

Azobenzenes—synthesis and carbohydrate applications

“…[92][93][94][95][96][97][98][99] Between the two methods described above, two classes of derivatives can be obtained: the symmetrical and the dissymmetrical azobenzenes. The synthesis of symmetrical azobenzene derivatives was effected by: (i) oxidation reactions of aromatic primary amines; [19][20][21][22][23][24][25][26][27][28][29][30] (ii) reduction reactions of aromatic compound having nitro groups; [32][33][34][35][36] (iii) diazo-coupling via diazonium salts; [54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71] and (iv) coupling reactions with arenediazonium salts. 100,101 The synthesis of dissymmetrical azobenzene derivatives was effected by: (i) oxidation reactions of aromatic primary amines; 31 (ii) coupling of primary arylamines with nitroso compounds (Mills reaction); [37]…”

1-(4-Cyanophenyldiazen-2-ium-1-yl)-2-naphtholate

“…Azo compounds are characterized by the azo linkage (-N=N-) and are very important in the fields of dyes, pigments and advanced materials (Lee et al, 2004;Oueslati et al, 2004). We report herein the crystal structure of the title compound, obtained through the diazotization of 4-aminobenzonitrile followed by a coupling reaction with 2-naphthol.…”

“…For general background to azo compounds and their use in dyes, pigments and advanced materials, see: Lee et al (2004); Oueslati et al (2004). For a related structure, see: Rȃ dulescu et al (2006).…”

(E)-1-(3-Chlorophenyl)-2-(2-oxidonaphthalen-1-yl)diazen-1-ium

“…For general background to the use of azo compounds as dyes, pigments and advanced materials, see: Lee et al (2004); Oueslati et al (2004). Many azo compounds have been synthesized by diazotization and diazo-coupling reactions; for information, see: Wang et al (2003).…”