Structural investigations of novel indoloacridines

5,6-Dihydro-9-chloro-7-phenylindolo[3,2-c]acridinium sulfates (3a-c) were formed from 2,3,4,9-tetrahydro-1H-carbazol-1-ones (1a-c) on reaction with 2-amino-5-chlorobenzophenone. 3b and 3c are isostructural and all three sulfates crystallize in the triclinic system with the space group P 1 each with two crystallographically independent organic cations and one sulfate anion in the asymmetric unit. 3a exhibits the parameters a = 9.8896(17), b = 14.165(2) and c = 14.583(2) Å, α = 83.184(3)°, β = 78.985(3)° and γ = 75.903(3)°; 3b a = 10.5713(9), b = 14.5667(12) and c = 14.9947(13) Å, α = 90.916(1)°, β = 97.153(1)° and γ = 97.208(1)°; and 3c a = 10.5505(10), b = 14.6090(13) and c = 15.2960(14) Å, and α = 91.4310(10)°, β = 98.8630(10)° and γ = 98.9100(10)°. The structure of 3c exhibits voids of 286 Å3 of ill defined and disordered solvate molecules. The structure of 3a is both non-merohedrally twinned and also exhibits an interesting type of pseudosymmetry. All but the sulfate ion and the ethylene moieties also fit with a unit cell half the size with only one independent cation, and disordered ethylene moieties and sulfate anions. The choice of unit cell was made based on the diffraction pattern and the absence of disorder in the larger cell, pointing towards alternating ordered ethylene and sulfate units rather than randomly disordered ones. Index Abstract: [The structures of three indoloacridines 3a, 3b, and 3c with similar packing motifs are described. The structure of 3a is both non-merohedrally twinned and also exhibits an interesting type of pseudosymmetry by being a double volume ordered supercell of an alternative cell with disordered ethylene and sulfate anion moieties.] © 2008 Springer Science+Business Media, LLC.