Mechanochemical synthesis and characterization of tri-organotin(IV) complexes of 4-aminobenzoic acid and 4-cyanobenzaldehyde as potential antifungal agents

Mechanochemical synthesis of organotin (IV) complexes using green chemistry approaches reduces environmental pollutants by eliminating solvents and catalysts, while also improving energy efficiency. In this study, four organotin (IV) complexes were synthesized and characterized, specifically with tributyltin (IV)-4-aminobenzoic acid and dibutyltin (IV)-4-cyanobenzaldehyde as ligands. Various analytical techniques were employed for their characterization. FTIR results confirmed the formation of the complexes, with Sn-O and Sn-N bands appearing at ca. 750 cm-1 in the spectra of the respective complexes. Thermogravimetric analysis (TGA) indicated the presence of water of hydration and the incorporation of ligands. Additionally, the complexes' calcination temperatures and heat capacities were evaluated using Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC). For example, complexes B1, B3, and B4 exhibited high specific heat capacities of approximately 23.48, 30.46, and 25.22 J/g°C, respectively. This indicates that these complexes are the most thermally stable among all those synthesized, making them promising candidates for biological applications. X-ray fluorescence analysis revealed that the percentage of Sn content in B3 was 13.57 % (0.14 mmol), which is lower than that in B4, where the Sn content was 13.85 % (0.15 mmol). These findings indicate that the mechanosynthesis of complex compounds is more effective with longer reaction times. Notably, the synthesized organotin (IV) complexes have shown promising activity against certain fungal strains. For example, complex B2 exhibited greater efficacy against Aspergillus flavus compared to the standard drug. This finding suggests that these complexes could serve as potential candidates for the development of novel antifungal agents