The remarkable structural comparison between two-dimensional and three-dimensional of 4, 4′-trimethylenedipyridine/1, 3, 5-trifluoro-2, 4, 6-triiodobenzene co-crystal.

A two-dimensional (2D) co-crystal composed of 1, 3, 5-trifluoro-2, 4, 6-triiodobenzene and 4, 4′-trimethylenedipyridine via halogen bonding (I···N) was obtained on highly-oriented pyrolytic graphite, and was characterized by scanning tunnelling microscope supplemented by the density functional theory calculation. Its special structure at the interface was further compared with its three-dimensional (3D) co-crystal structure. No orderly structures were observed when Au (111) was applied. The 2D co-crystal grown on the interface is significantly different from the 3D co-crystal. This study is of vital significance in understanding the growth mechanisms of 2D functional co-crystals. • Achieving TMDP (C13H14N2) and 3F3I (C6F3I3) 2D/3D co-crystals. • Gold and highly-oriented pyrolytic graphite (HOPG) substrates used. • Compared to Au, HOPG substrate has an effect on the growth of 2D co-crystal. • Unsaturated/saturated 3F3I molecules present in the 3D TMDP/3F3I co-crystal. [ABSTRACT FROM AUTHOR]