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The photochemistry of 6‐phenanthridinecarbonitrile I. Product analysis
Author(s) -
Vittimberga Bruno M.,
Sears Donald F.
Publication year - 2000
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570370212
Subject(s) - chemistry , photochemistry , benzophenone , methanol , phenanthridine , hydrogen atom abstraction , singlet state , excited state , molecule , triplet state , hydrogen , organic chemistry , physics , nuclear physics
Abstract When 6‐phenanthridinecarbonitrile ( 3 ) is irradiated at 2537 Å in neutral 9:1 2‐propanol/water, three major products are formed. These are dimethyl‐(6‐phenanthridinyl)methanol ( 4 ), phenanthridine ( 5 ) and 6,6′‐biphenanthridine ( 6 ). When benzophenone is present in the reaction mixture, diphenyl‐(6‐phenanthridinyl)‐methanol is also formed. 6‐Phenanthridinyl radical which is common to the formation of all these products, is formed by a monophotonic process involving hydrogen atom abstraction from an alcohol molecule by an excited state of 3 . Unlike what is generally found with other nitrogen‐heterocycles, the photochemistry of 3 appears to involve only a π,π* singlet state. The fluorescence of 3 is quenched with the triplet quencher cis/trans‐piperylene as a function of the concentration of the diene without the accompaniment of an exci‐plex emission.