Heteroleptic Zn(II) Anilate-Based 3D Coordination Polymer with Luminescent Properties

We report the synthesis and photophysical properties of a new crystalline ZnII-based heteroleptic coordination polymer, Zn2(trz2An)(trz)2, obtained from the combination of 3,6-N-ditriazolyl-2,5-dihydroxy-1,4-benzoquinone ligand (H2trz2An) and 1H-1,2,4-triazole (Htrz). Single-crystal X-ray diffraction reveals the formation of an extended network of Zn-triazole layers pillared by anilate ligands, resulting in an overall three-dimensional connectivity reminiscent of the heavily researched CALF-20(Zn). In contrast to CALF-20, the π-conjugated anilate pillars impart a richer electronic structure, giving rise to ligand-centered excited states and detectable luminescence. Photophysical investigations reveal that the optical response is dominated by the intrinsic photosensitivity of the anilate unit and is further modulated by metal coordination and framework formation. These findings further expand the ever-growing coordination chemistry of trz2An2− linkers and demonstrate that the combination of π-conjugated anilate ligands with N-donor co-ligands is a promising strategy for the design of light-responsive coordination frameworks and, in this case, the assembly of a new heteroleptic anilate-based coordination framework with luminescent properties.