Diazonium zinc chloride double salts

Generalized Procedure for Preparation of Diazonium Zinc Chloride Double Salts [45a]... 

Grignard reagents and diazonium zinc chloride double salts have been used to prepare azo compounds. The reaction of arylzinc chloride with a diazonium salt has also been used. By this means, mixed aromatic-aliphatic azo compounds have been prepared. 

Macrae and Wright (96) demonstrated that visible light irradiation of xanthene dyes (eosin, erythrosin, rhodamine B, or RB) in ethanolic solutions of 4-(N,N-diethylamino)benzene-diazonium chloride (as the zinc chloride double salt) resulted in decomposition of the diazonium salt. Electron transfer from the dye excited state(s) to the diazonium salt was postulated and dye-diazonium salt ion pair formation in the ground state was shown to be important. Similar dyes and diazonium salts were claimed by Cerwonka (97) in a photopolymerization process in which vinyl monomers (vinylpyrrolidone, bis(acrylamide)) were crosslinked by visible light. Initiation occurs by the sequence of reactions in eqs. 40-42 ... 

Diazoben. See 4-Dimethylaminoazobenzene-4-sulfonic acid, sodium salt Diazobicyclooctane 1,4-Diazobicyclo [2.2.2] octane. See Triethylene diamine p-Diazodimethylaniline zinc chloride double salt Synonyms p-Diazotized aminodimethylaniline zinc chloride double salt p-Dimethylaminobenzene diazonium chloride, zinc chloride double salt Empirical CsHioCINs Cl2Zn Formula (CH3)2NC6H4N2CI ZnCb Properties Yel. to orange cryst. 

Diazonium. See Diazomethane Diazophenyl black BW. See Direct black 80 Diazopon SS-837. See Nonoxynol p-Diazotized aminodimethylaniline zinc chloride double salt. See p-Diazodimethylaniline zinc chloride double salt Diazotizing salts. See Sodium nitrite Diazyme L-200. See Amyloglucosidase DIBA DiBA. See Diisobutyl adipate DIBAC. See Diisobutylaluminum chloride DIBAH. See Diisobutylaluminum hydride DIBAL-E. See Diisobutylaluminum ethoxide DIBAL-H. See Diisobutylaluminum hydride DIBAL-O. See Bis (diisobutylaluminum) oxide DIBAL-BOT. See Diisobutylaluminum butylated oxytoluene... 

Another group of stable diazonium salts are the so-called diazonium metal double salts the zinc double chlorides are particularly important. The term is misleading,... 

The Nesmeyanov reaction can also be used for arylarsine syntheses. Usually double salts of diazonium chlorides with zinc chloride are treated with arsenic trichloride and zinc dust in acetone (Hanby and Waters, 1946). Nesmeyanov s school used mainly double salts with ferric chloride and iron powder (Nesmeyanov and Makarova, 1950 Reutov and BundeP, 1955). 

Another group of stable diazonium salts are the so-called diazonium metal double salts the zinc double chlorides are particularly important. The term is misleading, as they are not associations between two salts but, in the case of Zn, are formed from two arenediazonium ions with the complex anion ZnCL 2-. This fact became obvious from crystal structure studies38-41. The reason for their increased stability relative to ArN2+Cl- salts is that ZnCLt2- complex ions are less nucleophilic than free chloride ions. 

A few diazonium salts are unstable in solution, and many are in the solid state. Of these, the azides, chromates, nitrates, perchlorates (outstandingly), picrates, sulfides, triiodides and xanthates are noted as being explosive, and sensitive to friction, shock, heat and radiation. In view of their technical importance, diazonium salts are often isolated as their zinc chloride (or other) double salts, and although these are considerably more stable, some incidents involving explosive decomposition have been recorded. 

Diazonium salts can be stabilized to some extent by conversion to so-called double salts. The easiest to form are those with zinc chloride. Species such as [ArN ljIZnCI ] are reasonably stable in solution, especially if kept cold. 

Zinc is considered to be a borderline transition metal. ZnCl2 is used as an additive to arenediazonium chlorides because it increases the inertness ( kinetic stability ) towards explosive dediazoniation. Three X-ray investigations of such so-called double salts (ArNi )2ZnCl4 (see Zollinger, 1994, p. 24) reveal that the two diazonium ions are not coordinated to the metal atom (Mostad and Romming, 1968). These compounds are not, therefore, complexes containing aryldiazenido ligands. 

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