Triphenylmethyl radical

The triphenylmethyl radical (often shorted to trityl radical) is a persistent radical and the first radical ever described in organic chemistry. It can be prepared by homolysis of triphenylmethyl chloride 1 (scheme 1) by a metal like silver or zinc in benzene or diethyl ether. The radical 2 forms a chemical equilibrium with the quinoid type dimer 3(3-triphenylmethyl-6-diphenylmethylidene-1,4-cyclohexadiene). In benzene the concentration of the radical is 2%.