1：Experimental Design and Method Selection:

The study involved solvothermal synthesis of five MOFs using a novel ligand H2L with different metal ions (Zn, Cd, Mn, Co) to explore structural diversity and luminescent properties. Theoretical models for coordination chemistry and photoluminescence were employed.

2：Sample Selection and Data Sources:

The ligand H2L was synthesized from 4-formylbenzoic acid and 8-hydroxyquinaldine. Metal salts (e.g., ZnCl2, CdI2, MnCl2, CoCl2) were used as received. Single crystals were grown for structural analysis.

3：List of Experimental Equipment and Materials:

Equipment included FTIR spectrometer (Nicolet Magna 750), NMR spectrometer (Mercury plus 400), PXRD diffractometer (DMAX2500), TGA analyzer (STA449C), luminescence spectrometer (LS 50B and FLS920), UV?vis spectrophotometer (TU-1810), ESI-MS spectrometer (Finnigan LCQ), and single-crystal X-ray diffractometer (Bruker APEX). Materials included various solvents (DMF, MeOH, Diox, etc.), metal salts, and organic compounds.

4：Experimental Procedures and Operational Workflow:

Synthesis of H2L involved condensation and hydrolysis steps. MOFs were synthesized by heating mixtures of H2L and metal salts in solvents at 80°C for 12 hours. Crystals were harvested, rinsed, and dried. Sensing experiments involved dispersing ground samples in solvents or aqueous solutions with analytes, ultrasonication, and luminescence measurement.

5：Data Analysis Methods:

Structural data were solved using direct methods and refined with full-matrix least squares. Luminescence data were analyzed using double-exponential decay functions. Quenching efficiencies were calculated, and detection limits were determined based on IUPAC criteria.