1736-09-0Relevant articles and documents
A product analytical study of the thermal and photolytic decomposition of some arenediazonium salts in solution
Canning, Peter S. J.,Maskill, Howard,McCrudden, Katharine,Sexton, Brian
, p. 789 - 800 (2007/10/03)
Products of thermal and photochemical reactions of eleven arenediazonium tetrafluoroborates in various solvents have been analyzed. All compounds in most solvents undergo unimolecular heterolysis to give singlet aryl cations which are captured by solvent. This mechanism is dominant for arenediazonium ions without electron-withdrawing substituents in all solvents, and the only reaction observed in water. Additionally, appreciable yields of fluoroarenes are obtained by fluoride abstraction by the aryl cation from fluorinated solvents and from tetrafluoroborate in fluorinated solvents. Yields from photochemical processes are very similar to those from thermal reactions indicating that the main reactions proceed through common or very similar intermediates. Aryl cations formed from ion-paired diazonium ions may react with the counterion, but fragmentation of dissociated diazonium ions leads only to solvent-derived product. Some arenediazonium ions in some solvents undergo an alternative radical reaction leading principally to hydrodediazoniation. It is proposed that this reaction involves initial rate-limiting electron transfer from ethanol to the arenediazonium ion followed rapidly by homolysis of the resultant aryldiazenyl radical. Within the same solvent cage, the aryl radical then either abstracts an α-hydrogen from the ethanol radical cation generated in the first step to give the reduction product and protonated acetaldehyde, or combines with it at the oxygen to give a protonated aryl ethyl ether.
Selectivity of the Aromatic Plumbylation Reaction
Stock, Leon M.,Wright, Terry L.
, p. 4645 - 4648 (2007/10/02)
The plumbylation of toluene in dichloroacetic acid yields initially 5.4percent 2-, 1.8percent 3-, and 92.7percent 4-methylphenyllead(IV) dichloroacetates.The toluene to benzene rate ratio under these conditions is 59.9.The partial rate factors are oMef = 9.64, mMef = 3.21, pMef = 331.The plumbylation of toluene in trifluoroacetic acid yields aryl trifluoroacetates and biaryls.Analysis of these products suggest that the plumbylation reaction yields 17.9percent 2-, 3.2percent 3-, and 78.9percent 4-methylphenyllead (IV) trifluoroacetates in the initial step of the reaction.The toluene to benzene rate ratio is 114 under these conditions.The partial rate factors are oMef = 61.2, mMef = 10.8, and pMef = 540.These observations suggest that the plumbylation reaction is a typical electrophilic substitution and that the reaction is significantly more selective than thallation or mercuration.
