1：Experimental Design and Method Selection:

The study involved synthesis of complexes from aqueous solutions, characterization using NMR, mass spectrometry, X-ray diffraction, and DFT calculations to understand structures and properties.

2：Sample Selection and Data Sources:

Starting materials included K3[Ir(NO2)6] prepared from iridium trichloride, and 2,2'-bipyridine; samples were isotopically enriched with 15N for NMR studies.

3：List of Experimental Equipment and Materials:

Equipment included UV-Vis spectrophotometer, IR spectrometer, CHN analyzer, X-ray diffractometer, NMR spectrometer, mass spectrometer, and computational software. Materials included acids, bases, solvents, and ligands.

4：Experimental Procedures and Operational Workflow:

Procedures involved boiling reactions, pH adjustments, crystallization, and spectroscopic measurements; detailed steps are described in the preparation and characterization sections.

5：Data Analysis Methods:

Data were analyzed using software for NMR, mass spectrometry, X-ray structure refinement, and DFT calculations to interpret results.