Synthesis and Structural Characterization of (H2dabco)[CuIIBr4]

The (H2dabco)[CuIIBr4] salt (dabco = 1,4-diazabicyclo[2.2.2]octane) was obtained and structurally characterized. The structure consists of isolated H2dabco2+ cations and pseudo-tetrahedral CuIIBr42– anions linked via N–H…Br hydrogen bonds along the 001 direction. Because the β-angle is very close to 90°, the unit cell parameters were examined over a temperature range from 290 to 90 K. No signs of a phase transition were observed. Strong distortion of the tetrahedral geometry of the CuIIBr42− anion was discussed. The Hirshfeld surface was constructed and analyzed to better understand the nature of weak interactions.