Seven Zn(II) and Cd(II) 1D coordination polymers based on azine donor linkers and decorated with 2-thiophenecarboxylate: Syntheses, structural parallels, Hirshfeld surface analysis, and spectroscopic and inclusion properties

Of seven mixed-ligand 1D coordination polymers—[Zn2(4-bphz)(2-tpc)4]n (1), [Zn2(4-bpmhz)(2-tpc)4]n (2), [Cd(4-bphz)2(2-tpc)2]n (3), [Zn(3-bphz)(2-tpc)2]n (4), [Zn(3-bpmhz)(2-tpc)2]n (5), [Cd(4-bpmhz)(2-tpc)2]n·0.5n(4-bpmhz) (6), [Cd(3-bpmhz)(2-tpc)2]n· 0.5n(H2O) (7) (where 2-tpc = 2-thiophenecarboxylate, 4-bphz = 1,2-bis(pyridin-4-ylmethylene) hydrazine, 4-bpmhz = 1,2-bis(1-(pyridin-4-yl)ethylidene)hydrazine, 3-bphz = 1,2-bis(pyridin- 3-ylmethylene)hydrazine, and 3-bpmhz = 1,2-bis(1-(pyridin-3-yl)ethylidene)hydrazine) the guest-free arrays 1–5 pack in the parallel stacking modes, while the inclusion compounds 6 and 7 reveal criss-cross packing arrangements with large channels where guest molecules (4-bpmhz/water) serve as structure-directing templates. The distributions of intermolecular interactions in 1–7 were quantified by Hirshfeld surface and fingerprint plots analysis. The guest-exchange properties for 6 and the solid state emissive properties for 1–7 are reported.