PHOTOCHEMICAL REACTIONS OF ARENECARBONITRILES WITH ALIPHATIC AMINES. 1. EFFECT OF ARENE STRUCTURE ON AMINYL VS. alpha -AMINOALKYL RADICAL FORMATION.

Article abstract of DOI:10.1021/ja00313a038

The photochemical reactions of several singlet arenecarbonitriles with aliphatic amines have been investigated. The reactions of 9-phenanthrenecarbonitrile with diethylamaine and its N- and alpha -C deuterated derivatives result in exclusive N-H atom transfer to yield the diethylaminyl and 9-cyano-9,10-dihydrophenanthren-9-yl radicals in benzene solution. Increased solvent polarity results in the formation of both diethylaminyl and 1-(ethylamino)ethyl radical. Similar results are obtained with 9-anthracenecarbonitrile. The competition between aminyl vs. alpha -aminoalkyl radical formation in this and other reactions is reviewed. Aminyl radical formation is characteristic of relatively nonpolar heteroexcimers in which hydrogen bonding may favor N-H transfer. Pure charge-transfer exciplexes, like alkoxyl radicals, yield predominantly the thermodynamically more stable alpha -aminoalkyl radical.