Binary and ternary charge-transfer complexes using 1,3,5-trinitrobenzene

Three binary and one ternary charge-transfer complexes have been made using 1,3,5-trinitrobenzene, viz. 1,3,5-trinitrobenzene-2-acetylnaphthalene (1/1), C₆H₃N₃O₆C₁₂H₁₀O, (I), 1,3,5-trinitrobenzene-9-bromoanthracene (1/1), C₁₄H₉BrC₆H₃N₃O₆, (II), 1,3,5-trinitrobenzene-methyl red (1/1), C₁₅H₁₅N₃O₂C₆H₃N₃O₆, (III) (systematic name for methyl red: 2-((E)-[4-(dimethyl-amino)phenyl]diazenyl}benzoic acid), and 1,3,5-trinitrobenzene-1-naphthoic acid-2-amino-5-nitropyridine (1/1/1), C₆H₃N₃O₆C₁₁H₈O₂C₅H₅N₃O₂, (IV). All charge-transfer complexes show alternating donor and acceptor stacks, which have weak C-H O hydrogen bonds perpendicular to the stacking axis. In addition, complex (IV) is a crystal engineering attempt to modify the packing of the stacks by inserting a third molecule into the structure. This third molecule is stabilized by strong hydrogen bonds between the carboxylic acid group of the donor molecule and the pyridine acceptor molecule.