C-H···O hydrogen bonds in molecular complexes of 1,3,5-trinitrobenzene with some N-heterocycles

The crystal structures of the molecular complexes of sym-trinitrobenzene (TNB) with acridine, 1,10-phenanthroline and phenazine are discussed. In all three cases, the structures are held together by C-H···O Π···Πand interactions, and TNB forms hydrogen bonded dimers and tapes that are not found in its native crystal structure. Acridine and 1,10-phenanthroline yield 1:1 complexes that have very similar structures. The related molecule phenazine, however, gives a different 2:3 complex in which guest exchange, as seen in other recently reported examples, is not observed. A case is made for the reporting of such "low yield" supramolecular reactions because they still provide valuable information about the packing characteristics of organic molecules