Triiodide-Based Chair-Like Copper Complex Assembled by Halogen Bonding

Cocrystallization of the dimeric [Cu2(μ-I)2(CNXyl)4] (Xyl = 2,6-Me2C6H3, 1) and polymeric catena-[Cu(μ-I)(CNC6H3-2-Cl-6-Me)2] (2) complexes with I2at different molar ratios between the reactants resulted in a series of (RNC)2CuI-based crystal polyiodides formed along with gradual accumulation of iodine, namely the cocrystals [1·I2]·[Cu(μ1,1-I3)(CNXyl)2]2followed by the generation of [Cu(μ1,3-I3)(CNXyl)2]2·2I2(5·2I2) or [Cu(μ1,1-I3)(CNC6H3-2-Cl-6-Me)2]2and then [Cu(μ1,3-I3)(CNC6H3-2-Cl-6-Me)2]n·n/2I2. The polyiodide 5·2I2exhibits a novel supramolecular motif─a purely inorganic halogen-bonded Cu2(μ1,3-I3)2core in the chair conformation. The X-ray structure of 5·2I2featuring I···I contacts was analyzed by a set of theoretical methods and attributed to moderately strong halogen bonding (from −3.2 to −3.9 kcal/mol); these interactions determine the supramolecular architecture of 5·2I2.