Synthesis, characterization, structural elucidation and biological screening of some bis(diisobutyldithiophosphato)antimony(III) complexes

Seven complexes of type [(C4H9i-O)2PS2]2SbR have been synthesized by the reaction of chlorobis(diisobutyldithiophosphato)antimony(III) with mixed thio and/or oxo donor ligands in 1:1 M stoichiometry, where R = SC6H5, OOCC6H5, SCH2COOH, SOCCH3, OOCCH3, SC6H4COOH and OOC(OH)C6H4. These newly synthesized derivatives have been characterized by different physicochemical (elemental analysis (C, H, S, Sb), melting point, molecular weight determination), spectral (UV, IR, NMR (1H, 13C and 31P)) studies, as well as ESI mass, thermal, powder XRD and biological studies. In the final step of weight loss in thermogravimetric analysis, occurring in the range of 245–505 °C, the degradation of the C6H3CO moieties takes place and antimony sulfide (1/2 Sb2S3) is obtained as remaining material, which is useful in various aspects. Bonded to antimony the diisobutyldithiophosphato substituent behaves as an anisobidentate ligand, which is confirmed through spectral analysis. Powder XRD studies indicate that these compounds crystallize in a monoclinic crystal system with an unit cell volume of ∼7074–7162 Å3 forming nano ranged (9.69–15.69 nm) crystallites. From the antimicrobial screening tests, bis(diisobutyldithiophosphato)antimony(III) thioglycolate (compound 3) has shown a maximum zone of inhibition (19 mm) against E. coli at 200 μg mL−1 concentration.