Synthesis and integrated physicochemical–biological characterization of arsenic(III) bis(N,N′-diethyldithiocarbamato-S,S′) complexes with mixed thio and oxo donor ligands

Abstract

A series of new arsenic(III) bis(dithiocarbamate) complexes with mixed thio and oxo donor ligands were synthesized via a targeted replacement reaction using arsenic(III) bis(N,N’-diethyldithiocarbamato-S,S’) chloride as the precursor. The powder XRD revealed nano-sized crystalline domains (20.63–23.01 nm) and monoclinic symmetry with unit cell volumes ranging from 1269–1280 Å^³. In the ESI-MS spectra, specific fragmentation patterns indicated the selective loss of SOCCH₃ and OOCCH₃ in compounds 4 and 5, respectively, yielding a notable base peak at 371.0 m/z. Compound 6 (arsenic(III) bis(N,N’-diethyldithiocarbamato-S,S’) thiosalicylate) decomposed thermally to form stable arsenic sulfide, aligning well with the predicted elemental composition. Thermal stability was confirmed through TGA and DTG analysis. Functionally, the nano-scale and unique structural features of these complexes confer enhanced antimicrobial properties, outperforming both free ligands and standard drugs. Using chloramphenicol and terbinafine as references, these derivatives demonstrated significant inhibition zones, suggesting promising applications in antimicrobial therapeutics. This study not only expands the understanding of arsenic-based coordination complexes but also underscores their potential as bioactive materials in medicinal chemistry.