Biofilm inhibition by a new Mn(II) complex with Sulfamethoxazole: Synthesis, spectroscopic characterization and crystal structure (original) (raw)

a b s t r a c t The reaction in alkaline aqueous solution between sulfamethoxazole (SMX) and manganese (II) chloride produces colorless crystals with formula [Mn(H 2 O) 6 ] 0.5 [Mn(SMX) 3 ], which was characterized by UV-Vis, IR and Raman spectroscopy and thermal analysis. The crystal structure of [Mn(H 2 O) 6 ] 0.5 [Mn(SMX) 3 ] complex has been solved by X-ray diffraction methods. It crystallizes in the cubic Pa-3 space group with a = 19.5476(1) Å, and Z = 8 molecules per unit cell. [Mn(SMX) 3 ] À complex is at a crystallographic special position of C 3 symmetry with the Mn(II) ion cis-coordinated to three equivalent sulfamethoxazole molecules acting as bidentate ligands in a propeller-like conformation. [Mn(H 2 O) 6 ] 2+ hydrate ion is at crystal special position of S 6 symmetry with the metal in an almost perfect octahedral coordination with six water molecules. At 100 lg/mL Mn(H 2 O) 6 ] 0.5 [Mn(SMX) 3 ] and SMX, inhibited the Staphylococcus aureus biofilm formation by 92% and 54%, respectively. However, at the same concentration Mn(H 2 O) 6 ] 0.5 [Mn(SMX) 3 ] and SMX inhibited the planktonic bacterial growth by 52% and 81%, respectively. The Mn(II) complex inhibited the biofilm formation in values higher than 35% at the concentration 0.5 lg/mL. These results suggest that the metal complex [Mn(H 2 O) 6 ] 0.5 [Mn(SMX) 3 ] is a good candidate for the development of new antimicrobial agent acting in part as bactericidal but mainly as antipathogenic agent.