The reaction of organobismuth precursors with trityl-H-phosphinic acid in varying reaction conditions afforded colorless crystals, whose single crystal X-ray characterization revealed the formation of monomerThe reaction of titanium isopropoxide with two different phosphinic acids trityl-H-phosphinic acid and cycP(O)(OH) led to isolation of cubane type octahedral complex {Ti 8 (μ 2 -O) 8 (μ 2 -OH) 4 [(Ph 3 C)(H)PO 2 ] 12 }[3C 7 H 8 ] (3) and hexanuclear complex Ti 6 (μ 2 -cycPO 2 ) 9 (μ 2 -O) 6 (μ 2 -OH) 3 •4CH 3 CN•4H 2 O (4) respectively.

Isolation and structural characterization of novel organoantimony­(V)-based oxo clusters are reported. (RSb)4(OH)4(t-BuPO3)6 and (RSb)2(O)­(t-BuPO3H)6 independently in the presence of pyridine under solvothermal conditions afford the hexanuclear organoantimonate clusters [(RSb)6(μ3-O)2(μ2-O)6(t-BuPO3)4], where R = p-i-PrC6H4 (1), p-ClC6H4 (2). Further, reaction of organostibonate phosphonate with Ti­(O i Pr)4 in the presence of pyridine under solvothermal conditions afforded the mixed-metal titanium stibonate hexanuclear clusters [(RSb)2Ti4(μ3-O)2(μ2-O)2(t-BuPO3)4(μ-OCH3)4(OCH3)4], where R = p-i-PrC6H4 (3), p-ClC6H4 (4). Band gap measurements were performed on 1–4. They reveal a remarkable reduction in the band gap on moving from the heavier main-group-based oxo cages (1 and 2) to the titanium-incorporated oxo cages (3 and 4).

The reactions of [Zn3Cl2(3,5-Me2PzH)4(t-BuPO3)2] with organostibonic acid in varying reaction conditions have been investigated. Single-crystal X-ray diffraction studies reveal the formation of [Zn2(p-ClC6H4Sb)2(O)2(OCH3)2(t-BuPO3)3(py)2] (1), [Zn2(p-ClC6H4SbV)4(SbIII)2(O)8(t-BuPO3H)4(t-BuPO3)2(py)2Cl2] (2), and [Zn2(RSb)4(O)4(OCH3)4(t-BuPO3)4(py)2], where R = p-ClC6H4 (3) and R = p-iPrC6H4 (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 (1H, 31P, and 13C) 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.