Pyridine reactions with diphenyldiazomethane

The kinetics of the reaction of triplet diphenylcarbene with pyridine has been studied.108 Laser flash photolysis of diphenyldiazomethane in the presence of pyridine results in the formation of pyridinium ylide 200. This reactive species shows an absorption band at 500 nm. Based on the low activation energy of the reaction, it was concluded that the data were inconsistent with a simple preequilibrium model. Instead, it was suggested that the intersystem crossing step occurs at a point other than at the minimum of singlet diphenylcarbene.108... 

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