Structural Variants and Ultralow Detection Ability for Tryptamine in Two Polymorphs of a Zincophosphite Framework.

Two organic-inorganic hybrid zinc phosphites incorporating 1,2,4,5-tetrakis(imidazol-1-ylmethyl)benzene (TIMB) molecules were synthesized under hydro(solvo)thermal methods and structurally characterized by single-crystal X-ray diffraction (SCXD). Interestingly, the solvent ratio of water to dimethylformamide induced the formation of a new compound of Zn(TIMB)(HPO)·3HO () and our previously reported structure of Zn(TIMB)(HPO)·HO (). Additionally, their dehydrated crystals ( and ) were prepared through heat treatment at 150 °C. SCXD and powder X-ray diffraction showed that all four compounds share the same framework formula of Zn(TIMB)(HPO) but exhibit a huge difference in their inorganic components and final structures. In and , the inorganic units formed two-dimensional zincophosphite layers, while in and , they formed one-dimensional chains. The inorganic parts of () and () were bridged with TIMB linkers, resulting in 3D structures with rectangular and tubular windows, respectively. Furthermore, was coated on the screen-printed carbon electron as a hybrid material, displaying excellent performance while having a linear relationship with an value of 0.99 within the concentration range of 10 to 10 mol/L for detecting tryptamine (Try) molecules. Moreover, the results showed that exhibits an ultralow limit of detection of 5.43 × 10 mol/L and high specificity toward Try over histamine, ascorbic acid, uric acid, and glucose. The synthesis, structural diversity, stability, and sensing ability are also discussed.