1：Experimental Design and Method Selection:

The study involved the synthesis of two MOFs using hydrothermal methods with mixed organic ligands and metal salts. The rationale was to explore structural diversity and luminescent properties for sensing applications. Theoretical models included coordination chemistry principles for structure determination and luminescence mechanisms (e.g., ligand-based luminescence, charge transfer).

2：Sample Selection and Data Sources:

Samples were synthesized from commercially available chemicals: 1,3-di(1H-imidazol-4-yl)benzene (L) prepared as per literature, 1,4-phenylenediacetic acid (H2pda), Ni(NO3)2·6H2O, Cd(NO3)2·4H2O, NaOH, and various solvents (DMF, ethanol, methanol, etc.). Selection criteria focused on purity and reactivity for MOF formation.

3：List of Experimental Equipment and Materials:

Equipment included PerkinElmer 240C elemental analyzer for EA, Bruker Vector 22 FT-IR spectrometer for IR spectra, Bruker D8 Advance for PXRD, MettlerToledo TGA/DSC1 thermal analyzer for TGA, Aminco Bowman Series 2 spectrofluorometer for photoluminescence, and Bruker Smart Apex II CCD for X-ray crystallography. Materials: KBr pellets for IR, various solvents for sensing studies.

4：Experimental Procedures and Operational Workflow:

Synthesis involved sealing mixtures in Teflon-lined stainless steel containers, heating at 120°C for 3 days, cooling to room temperature, and isolating crystals. Procedures included elemental analysis, IR spectroscopy, PXRD, TGA, luminescence measurements (excitation at 308 nm, emission at 346 nm), and sensing tests by immersing samples in solvent or ion solutions, controlling variables like concentration and temperature.

5：Data Analysis Methods:

Data analysis used software like SAINT and SADABS for crystallography, SHELXS-2016 and SHELXL-2016 for structure solution and refinement. Luminescence data analyzed via Stern-Volmer plots to calculate quenching coefficients (Ksv) and detection limits using statistical methods (3σ/k).