Synthesis, crystal structure, thermal decomposition and sensitive properties of a new complex [Cu(IMI) ₄](PA) ₂

A new coordination complex [Cu(IMI) ₄](PA) ₂ had been synthesized with imidazole(IMI) as ligands and picrate(PA ) groups as outer anions, and characterized by Fourier transform infrared(FTIR) spectrum and elemental analysis. Its crystal structure was determined by single crystal X-ray diffraction(XRD) analysis. The crystallographic data show that the crystal belongs to monoclinic, C2/c space group, a=2.542(5) nm, b=0.91773(18) nm, c=1.3778(3) nm, β=107.854(3)° and Z=4. Furthermore, the central copper(II) ion is coordinated by four N atoms from four imidazole ligands. All the molecular units are linked into a zigzag pattern along a-axis by the hydrogen bonds, and extended to the distance regularly. Thermal decomposition mechanisms were determined based on differential scanning calorimetry(DSC) and thermogravimetry-differential thermogravimetry(TG-DTG) analysis, and kinetic parameters of the first exothermic process were studied using Kissinger's and Ozawa-Doyle's method, respectively. Sensitivity tests show that the title complex has low sensitivity to external stimulus, but it has a higher energy of combustion of 14.2 kJ/g due to which it may be used as the additives of energetic materials to improve the explosive performance.