Syntheses and X-ray structural studies of the novel complexes [Ni(en)2(3-pyt)2] and [Cu(en)2](3-pyt)2 based on 5-(3-pyridyl)-1,3,4-oxadiazole-2-thione

Synthesis, crystal structure and Hirshfeld surface analysis of a zinc(II) coordination polymer of 5-phenyl-1,3,4-oxa-diazole-2-thiol-ate

A new zinc coordination polymer with 5-phenyl-1,3,4-oxa-diazole-2-thiol-ate, namely, catena-poly[zinc(II)-bis-(μ2-5-phenyl-1,3,4-oxa-diazole-2-thiol-ato)-κ2 N 3:S;κ2 S:N 3], [Zn(C8H5N2OS)2] n , was synthesized. The single-crystal X-ray diffraction analysis shows that the polymeric structure crystallizes in the centrosymmetric monoclinic C2/c space group. The ZnII atom is coordinated to two S and two N atoms from four crystallographically independent (L) ligands, forming zigzag chains along the [001] direction. This polymer complex forms an eight-membered [Zn-S-C-N-Zn-S-C-N] chair-like ring with two ZnII atoms and two ligand mol-ecules. On the Hirshfeld surface, the largest contributions come from the short contacts such as van der Waals forces, including H⋯H, C⋯H and S⋯H. Inter-actions including N⋯H, O⋯H and C⋯C contacts were also observed; however, their contribution to the overall stability of the crystal lattice is minor.

Coexistence of Naked-Eye Mechanochromism, Vapochromism, and Thermochromism in a Soft Crystalline Layered Nickel(II) Coordination Polymer

Chromic materials have the potential to be used in a variety of applications, including memory devices and sensors. Despite fact that stimuli-responsive chromic materials have been widely reported to date, fabricating chromic materials that can be responsive to multiple external stimuli remains a challenge. Herein, a new multistimuli responsive chromic coordination polymer of {[Ni(pzt)₂(H₂O)₂](H₂O)(DMF)}_n (1); Hpzt = 5-(3-pyridyl)-1,3,4-oxadiazole-2-thiol, was successfully synthesized. Single-crystal X-ray diffraction analysis revealed that 1 exhibits a soft crystalline 3-dimenional (3D) supramolecular framework generated by weakly interlayered stacking interactions between 2D coordination polymers. Compound 1 revealed unprecedented naked-eye mechanochromism, vapochromism, and thermochromism in response to multiple external stimuli including manual grinding, amine and alcohol vapors, and heat, respectively. The chromism related to the structural feature was clarified by SC-XRD, PXRD, TGA, elemental analysis, and spectroscopic techniques.