Kinetics and mechanisms of reactions involving diazonium and diazo groups

A new method for monitoring dediazoniation reactions: Simultaneous monitoring of concentration and rates of product formation and loss of starting material for the dediazoniation ofp-methylbenzenediazonium tetrafluoroborate

“…Our From the slopes of these linear plots we can obtain values for k obs for ArOH formation in the absence of CuCl 2 and for error, to those following diazonium salt loss spectrophotometrically (Table II) and ArOH formation chromatographically (see before).…”

“…The field remains active [8] because their rich chemistry varies dramatically with experimental conditions [2,4] and because the many reaction pathways are still not completely understood [2,4,5]. Arenediazonium salts are being used to probe interfacial compositions of association colloids [9], as aryl radical sources for synthetic precursors [4,10,11] and their role in DNA arylations [12,13] and DNA deaminations [14] is being explored.…”

“…Arenediazonium reactions are normally divided [2,4,5] (Scheme I) into two groups, those that occur at the arene nucleus (dediazoniation reactions, 1a) and those that occur at the terminal nitrogen of the diazonium group (nucleophilic addition, 1b). Addition reactions are the classical route to obtain azo dyes and pigments [6].…”

“…(Y ϭ and catalyzed, e.g., the Sandmeyer [2,4,5] to occur by either heterolytic, (2a), or, in the presence of an electron donor, D, homolytic (2b) pathways (Scheme I). In the absence of catalysts, with weakly basic nucleophiles, in the presence of O 2 , in aqueous acid, and in the dark, dediazoniation reactions are believed to proceed via rate determining loss of N 2 , generating a highly reactive phenyl cation that reacts rapidly and with very low selectivity with available nucleophiles.…”

“…In the absence of catalysts, with weakly basic nucleophiles, in the presence of O 2 , in aqueous acid, and in the dark, dediazoniation reactions are believed to proceed via rate determining loss of N 2 , generating a highly reactive phenyl cation that reacts rapidly and with very low selectivity with available nucleophiles. In nonaqueous solvents, products associated with free radicals, e.g., biphenyl derivatives and replacement of Ϫ N 2 ϩ by Ϫ H, are often observed, especially when electron withdrawing groups are present on the arenediazonium ion [2,4,5].…”