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.