Structural and luminescent properties of co-crystals of tetraiodoethylene with two azaphenanthrenes

Two new co-crystals, tetraiodoethylene-phenanthridine (1/2), 0.5C(2)I(4)center dot C13H9N (1) and tetraiodoethylene-benzo[f]quinoline (1/2), 0.5C(2)I(4)center dot C13H9N (2), were obtained from tetraiodoethylene and azaphenanthrenes, and characterized by IR and fluorescence spectroscopy, elemental analysis and X-ray crystallography. In the crystal structures, C-I center dot center dot center dot pi and C-I center dot center dot center dot N halogen bonds link the independent molecules into one-dimensional chains and two-dimensional networks with subloops. In addition, the planar azaphenanthrenes lend themselves to pi-pi stacking and C-H center dot center dot center dot pi interactions, leading to a diversity of supramolecular three-dimensional structural motifs being formed by these interactions. Luminescence studies show that co-crystals 1 and 2 exhibit distinctly different luminescence properties in the solid state at room temperature.