Two mononuclear cobalt(Ⅱ) complexes, [Co(pytpy)₂](2-NH₂-1-NS)₂·MeOH·H₂O (1) and [Co(pytpy)₂](4-NH₂-1-NS)₂·H₂O (2), where pytpy=4'-(4-pyridyl)-2, 2'∶6', 2″-terpyridine, 2-NH₂-1-NS^-=2-amino-1-naphthalenesulfonate, and 4-NH₂-1-NS^-=4-amino-1-naphthalenesulfonate, were synthesized and characterized structurally and magnetically. Single-crystal X-ray analysis reveals that both complexes consist of the [Co(pytpy)₂]²⁺ cations, organosulfonate anions, and crystallized solvent molecules. The difference between the two anions is the relative position of the sulfonate and amino groups. Interestingly, the 2-NH₂-1-NS^- anion with the sulfonate and amino group in adjacent positions, forms hydrogen bonds with the [Co(pytpy)₂]²⁺ cation and solvent molecules, while the 4-NH₂-1-NS^- anion, with the sulfonate and amino groups in para positions, forms a 2D layer structure through hydrogen bonding. Magnetic measurements revealed significant differences in their magnetic properties: while complex 1 exhibits a reversible and gradual spin crossover behavior, complex 2 remains in the high-spin state.

A Cd(Ⅱ) complex, formulated as {(H₂dbim)_0.5[Cd(Hbptc)]·H₂O}_n (1), where dbim=1-(4-((2, 6-dimethyl-2H-benzo[d]imidazol-3(3H)-yl)methyl)benzyl)-2, 7-dihydro-2, 5-dimethyl-1H-benzo[d]imidazole, H₄bptc=3, 3', 4, 4'-benzophenone tetracarboxylic acid, has been obtained by hydrothermal reactions and structurally characterized. Complex 1 exhibits a 2D layer with a point symbol of {4⁴·6⁶}. Complex 1 was used for fluorescence identification of some common environmental pollutants. The result of the research shows that complex 1 can effectively detect p-nitrophenol, tetracycline, and 2, 6-dichloro-4-nitroaniline. The calculated quenching constants for p-nitrophenol, tetracycline, and 2, 6-dichloro-4-nitroaniline were 2×10², 5.4×10⁴, and 2×10⁴ L·mol^-1, respectively.