Synthesis, structure, photoluminescent and thermodynamic/kinetic properties of two interpenetration/polycatenation Zn(II) coordination polymers

Abstract Two novel zinc(II) coordination polymers, [Zn 2 (bib)(5-Br-ipa) 2 ]} n ( 1 ) and {[Zn(bib)(2,6-ndc)]} n ( 2 ) (bib = 1,4-bis(2-methyl-imidazol-1-yl)butane, 5-Br-H 2 ipa = 5-bromoisophthalic acid, 2,6-H 2 ndc = 2,6-naphthalenedicarboxylic acid) have been synthesized under the same solvothermal conditions and characterized by elemental analysis, IR spectroscopy, single crystal X-ray diffraction technology. Complex 1 shows a novel 3-fold interpenetrating architecture possessing a couple of single helices and a pair of rare tri-flexural helices. Complex 2 gives an unusual 2D + 2D → 3D inclined polycatenation architecture comprised of two sets of interlocked equivalent 2D layers. The fluorescent properties of complexes 1 and 2 were studied. In addition, the thermal decompositions of 1 and 2 were investigated by simultaneous TG/DTG–DSC techniques. The TG curves exhibit that complexes 1 and 2 possess good thermostability up to 320 °C and 315 °C, respectively. The enthalpy of the melting decomposition (Δ H d ) was measured. The apparent activation energy E and the pre-exponential factor ( A ) of skeleton collapse for the complexes were calculated by the integral Kissinger’s method and Ozawa–Doyle’s method. The thermodynamic parameters (Δ H ≠ , Δ G ≠ , and Δ S ≠ ) at the peak temperatures of the DSC curves were calculated. The structural stability could be illustrated from the point of thermodynamics and kinetics.