Discrete Molecular Aggregates Based on Zn II and Sb III/V Ions Displaying Efficient Antibacterial and Antioxidant Properties.

The reactions of [Zn ₃ Cl ₂ (3,5-Me ₂ PzH) ₄ ( t -BuPO ₃ ) ₂ ] with organostibonic acid in varying reaction conditions have been investigated. Single-crystal X-ray diffraction studies reveal the formation of [Zn ₂ ( p -ClC ₆ H ₄ Sb) ₂ (O) ₂ (OCH ₃ ) ₂ ( t -BuPO ₃ ) ₃ (py) ₂ ] ( 1 ), [Zn ₂ ( p -ClC ₆ H ₄ Sb ^V ) ₄ (Sb ^III ) ₂ (O) ₈ ( t -BuPO ₃ H) ₄ ( t -BuPO ₃ ) ₂ (py) ₂ Cl ₂ ] ( 2 ), and [Zn ₂ (RSb) ₄ (O) ₄ (OCH ₃ ) ₄ ( t -BuPO ₃ ) ₄ (py) ₂ ], where R = p -ClC ₆ H ₄ ( 3 ) and R = p -iPrC ₆ H ₄ ( 4 ), respectively. Interestingly, in the synthesis of 2 , complete dearylation of organoantimony moieties followed by C-F bond formation, a reduction from Sb (V) to Sb (III), and Sb···Cl weak intermolecular interactions have been observed. ESI-MS studies suggested that clusters 1 - 4 maintained their structural integrity in the solution state also. Solution NMR studies ( ¹ H, ³¹ P, and ¹³ C) support well the observed solid-state structures. 1 - 4 were tested for antibacterial activity using a microdilution assay. 1 and 4 showed the best activity with lower MIC values (0.78-6.25 μg/mL) against all the tested pathogens. The total antioxidant activity of 1 - 4 was evaluated through the phosphomolybdenum assay, which showed a total antioxidant activity ranging from 28.96 to 86.46 mg AAE/g compound with the ascorbic acid standard.