Arenediazonium sulfonates: synthesis, comparison of structural and physicochemical properties
Aromatic diazonium salts are important building blocks in organic synthesis. The present review is concerned with such aromatic diazonium sulfonates as tosylates, dodecylbenzenesulfonates, triflates, camphorsulfonates, silica sulfates. The first part of the review provides information on the synthesis and application of these diazonium salts. It is shown that these diazonium compounds are easily synthesized by diazotization of anilines with sodium nitrite or alkyl nitrites in the presence of corresponding sulfonic acids with high yields. These diazonium salts have found wide application in the synthesis of aromatic azides, halides, triazenes, azo dyes, stilbenes, biaryls, etc. The second part of the article presents information on the comparison of the results of X-ray analysis, infrared spectroscopy and thermal analysis. The structure of diazonium sulfonate salts corresponds to the structure of classical diazonium salts (chlorides, sulfates, tetrafluoroborates). A significant difference between arenediazonium sulfonates and other diazonium salts is their explosion safety and stability in an individual form. Arenediazonium tosylates, triflates and camphorasulfonates are easily soluble both in water and in polar organic solvents. Arenediazonium dodecylbenzenesulfonates are soluble in nonpolar organic media. These features of sulfonate salts are paramount for distinguishing characteristics of the effect of the acid anion on the stability, solubility and reactivity of diazonium salts.