Organoarsonate- and Dimethylarsinate-Functionalized Hexamolybdates(V): A Multifaceted Study on Synthesis, Structural Dynamics, and Antibacterial Properties

We report on the synthesis, functionalization, and structural characterization of 11 novel dimethylarsinate-functionalized arsenomolybdates(V), [RAsMo^V₆O₁₅(OH)₃{AsO₂(CH₃)₂}₃]^2- (R = HO, CH₃, C₂H₅, C₆H₅, 3,5-(HOOC)₂C₆H₃, 4-FC₆H₄, 4-F₃CC₆H₄, 4-F₃COC₆H₄, 4-BrC₆H₄, and 4-N₃C₆H₄) and [As^IIIMo^V₆O₁₅(OH)₃{AsO₂(CH₃)₂}₃]^3-, featuring a reduced hexanuclear {Mo^V₆O₂₄} core, peripherally coordinated by three dimethylarsinate ligands and centrally functionalized with diverse organoarsonate, arsenate, or arsenite groups, including carboxylated, fluorinated, brominated, and azido derivatives. Synthesized via a simple one-pot aqueous method, the compounds were thoroughly characterized by single-crystal X-ray diffraction, thermogravimetric analysis, and elemental analysis in the solid state. Solution-phase stability was assessed by multinuclear (¹H, ¹³C, and ¹⁹F) nuclear magnetic resonance, while gas-phase behavior and fragmentation pathways were probed through electrospray ionization mass spectrometry, and tandem mass spectrometry (collision-induced dissociation). Antibacterial screening against <i>Escherichia coli, Bacillus subtilis</i>, and three pathogenic bacterial strains <i>Listeria monocytogenes, Salmonella enterica</i>, and <i>Vibrio parahaemolyticus</i> revealed that three of the 11 polyanions exhibit moderate antibacterial activity. Additionally, the synthesis of 3,5-bis(carboxy)phenylarsonic acid, 3,5-(HOOC)₂C₆H₃AsO₃H₂, is reported here for the first time.