Morpholine- and Thiomorpholine-Based Amidodithiophosphonato Nickel Complexes: Synthesis, Characterization, P–N Cleavage, Antibacterial Activity and Silica Nano-Dispersion
The reactivity of thiomorpholinium P-(4-methoxyphenyl)-N-thiomorpholin-amidodithiophosphonate (S-MorH+2)(S-Mor-adtp−) and morpholinium P-(4-methoxyphenyl)-N-morpholin-amidodithiophosphonate (O-MorH+2)(O-Mor-adtp−) towards nickel (II) dichloride hexahydrated is presented and the hydrolysis of the relevant metal complexes investigated. The hydrolytic products (S-MorH+2)2 [Ni(dtp)2]2− and (O-MorH+2)2[Ni(dtp)2]2− were characterized by means of FT-IR, 1H, and 31P NMR and XRD and the experimented P–N cleavage investigated and elucidated by means of DFT calculations. The antimicrobial activity of the neutral nickel complex [Ni(S-Mor-adtp)2] was tested against a set of Gram-positive and Gram-negative bacteria alongside with its nanodispersion in a silica matrix. The complex [Ni(S-Mor-adtp)2] did not show antibacterial activity, whilst the nano-dispersed sample [Ni(S-Mor-adtp)2]_SiO2 demonstrated inhibition to growth of Staphylococcus aureus. The nanocomposites were fully characterized by means of XRPD, TGA, SEM and dinitrogen sorption techniques.