Charge-transfer complexes of N-methyl-, N-isopropyl-, N-butyl- and N-isobutylcarbazole with 3,5-dinitrobenzoic acid.

In the title four compounds, C(13)H(11)N.C(7)H(4)N(2)O(6), (I), C(15)H(15)N.C(7)H(4)N(2)O(6), (II), C(16)H(17)N.C(7)H(4)N(2)O(6), (III), and C(16)H(17)N.C(7)H(4)N(2)O(6), (IV), the donor and acceptor molecules are stacked alternately to form one-dimensional columns. 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-isopropyl, N-butyl and N-isobutyl groups are in anti positions with respect to one of the nitro groups of the neighboring acceptor in compounds (II)-(IV).