Charge-transfer complexes of N-methyl-and N-ethylcarbazole with 3,5-dinitrobenzonitrile

The N-methyl group of the donor is nearly eclipsed with respect to one of the nitro groups of the neighboring acceptor in a column, whereas the N-ethyl group is anti with respect to the cyano group of the neighboring acceptor in (II). Crystals of (I) underwent photoredox reactions initiated by the excited nitro group, leading to oxidation of the N-alkyl groups. In (I), the N-methyl group of the donor is nearly eclipsed with respect to one of the nitro groups of the neighboring acceptor in a column, whereas the N-ethyl group is anti with respect to the cyano group of the neighboring acceptor in (II). Equimolecular mixtures of N-alkylcarbazoles and 3,5-dinitrobenzonitrile were recrystallized from methylene chloride [for (I)] and ethyl acetate [for (II)].