Dediazoniation of Arenediazonium Ions. Part XIX. Effect of thiocyanate ion in the reactions of 2,4,6‐trimethylbenzenediazonium tetrafluoroborate in 2,2,2‐trifluoroethanol

Abstract

SummaryThe dediazoniation of 2,4,6-trimethylbenzenediazonium tetrafluoroborate (1) in 2,2,2-trifluoroethanol (TFE) was studied in the presence of potassium thiocyanate. The effect of added salt on the dediazoniation rate, the N,-N, rearrangement (Eqn. 2), the exchange of the 15N-labelled diazo group with molecular nitrogen (Eqn. 3), and the reaction products was determined. With 0 . 3~ KSCN a decliazoniation-rate increase of 16.5% was achieved, and the amounts of rearranged and exchanged product were reduced to 88% and lo%, respectively, of the values found in pure TFE. The dediazoniation products formed are ArF (3), ArOCH2CF, (4), ArSCN (5), ArNCS (6) and traces of 5,7-dimethylindazole (7). All the data are in agreement with, and support the previously proposed mechanism (Equ. I ) of heterolytic dediazoniation of arenediazonium salts.Introduction. -The dediazoniation of 2,4,6-trimethylbenzenediazonium tetrafluoroborate (1) in 2,2, 2-trifluoroethanol (TFE) was shown to proceed via two intermediates, a tight aryl-cationlN,-molecule pair and a free aryl cation (Eqn. 1) [2-41.

Solvolysis of Some Arenediazonium Salts in Binary EtOH/H2O Mixtures under Acidic Conditions

“…Different research groups have proposed formation of ion-molecule pairs involving ground state arenediazonium ions. Zollinger et al [34] suggested the formation of ion molecule pairs with N 2 at high N 2 pressures. More recently, transient colored complexes between arenediazonium ions and aromatic hydrocarbons have been observed and characterized.…”

Solvolyses of 4‐methylbenzenediazonium ions in trifluoroethanol/water mixtures: Effects of [TFE], acidity and temperature on the kinetics and mechanism of the reaction

“…Various research groups have proposed the formation of ion–molecule pairs involving ground state arenediazonium ions. Zollinger and coworkers31 suggested the formation of ion–molecule pairs with N 2 at high N 2 pressures. More recently, transient coloured complexes between arenediazonium ions and aromatic hydrocarbons have been observed and characterized32 and solid arenediazonium tetrachlorocuprate(II) complexes33 have been isolated that decompose to give ArCl in high yields 34…”

Nitrogen fixation and transformation with main group elements

“…130,131 The detailed kinetic studies about the isotopic rearrangement and N 2 exchange reaction of aromatic diazonium salts provided more support to the dediazoniation equilibria mechanism between the diazonium salt, a tight aryl-cation/N 2 molecule pair and a free aryl cation (Scheme 11). 132–134 The dediazoniation of aromatic diazonium salts provided a possibility for an aromatic cation to undergo the reaction with nitrogen. However, this could not afford a nitrogen fixation method for the aromatic cations usually generated from the release of N 2 .…”

“…cation (Scheme 11). [132][133][134] The dediazoniation of aromatic diazonium salts provided a possibility for an aromatic cation to undergo the reaction with nitrogen. However, this could not afford a nitrogen fixation method for the aromatic cations usually generated from the release of N 2 .…”