Carbenium ions triaryl

Protonic initiation is also the end result of a large number of other initiating systems. Strong acids are generated in situ by a variety of different chemistries (6). These include initiation by carbenium ions, eg, trityl or diazonium salts (151) by an electric current in the presence of a quartenary ammonium salt (152) by halonium, triaryl sulfonium, and triaryl selenonium salts with uv irradiation (153—155) by mercuric perchlorate, nitrosyl hexafluorophosphate, or nitryl hexafluorophosphate (156) and by interaction of free radicals with certain metal salts (157). Reports of "new" initiating systems are often the result of such secondary reactions. Other reports suggest standard polymerization processes with perhaps novel anions. These latter include (Tf)4Al (158) heteropoly acids, eg, tungstophosphate anion (159,160) transition-metal-based systems, eg, Pt (161) or rare earths (162) and numerous systems based on tri flic acid (158,163—166). Coordination polymerization of THF may be in a different class (167). 

Cationic dyes form positively charged dye ions by dissociation, and the positive electric charge is delocalized over the entire molecule. They are usually di- and triarylmethine dyes such as C.I. Basic Green 4, 42000 [569-64-2] (31), which are also known as triarylmethane dyes or triaryl carbenium ions [15], oxazine dyes such as C.I. Basic Blue 3, 51005 [2787-91-9] (32), orthiazine dyes. 

All available experimental results [87] suggest that carbocations are just weakly coordinated to counterion or solvent. For trialkyl and triaryl substituted carbenium ions generated under superacid conditions, this has been demonstrated in a series of X-ray diffraction experiments in particular carried out by Laube and co-workers. [98-102] For example, for the 3,5,7-trimethyl-l-adamantyl cation and its counterion Sb2Fn, the closest C-F distance was measured to be 2.88 A suggesting that interactions between cation and anion are rather weak. [98]... 

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