Structural and Biological Insights Into Organotin(IV) Complexes of the Schiff Base Derived From Hexamethylenediamine and 2,4‐Dichlorobenzaldehyde

ABSTRACT A Schiff base N 1 ‐(2,4‐dichlorobenzylidene)hexane‐1,6‐diamine ( L) was synthesized by stirring 2,4‐dichlorobenzaldehyde with hexane‐1,6‐diamine in methanol. The ‘ L ’ was reacted with Me 2 SnCl 2 , Bu 2 SnCl 2 , Ph 2 SnCl 2 , and Ph 3 SnCl to produce the organotin(IV) products 1 , 2 , 3 and 4 , respectively. The products were characterized by elemental analysis (CHN), FTIR, NMR ( 1 H & 13 C), UV‐visible studies, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and computational studies. FTIR spectroscopy confirmed the penta‐coordinated solid structures, while UV–vis analysis showed π–π (benzene) and n–π (–C═N–) transitions. TGA indicated thermal decomposition, leaving Sn or Sn+C residues. The optimized molecular parameters were calculated using DFT at the B3LYP/6‐311G+ level of theory, verifying the trigonal bipyramidal coordination geometries. E HOMO , E LUMO , Δ E , electronic chemical potential (μ), electron affinity (A), ionization energy (I), dipole moment, chemical softness (σ), electrophilicity index (ω), and chemical hardness (η) were also calculated and compared. In comparison to free L , the complexes ( 1 ‐ 4 ) exhibited significantly improved antibacterial efficacy against B. subtilis and E. coli . The product 1 displayed 95% biofilm inhibition of E. coli , which was even higher as compared to that (85%) of standard drug‐ ciprofloxacin. The observed % lyses of the products 1 and 3 were almost in the safe range (9.51–11.56%), indicating their safe medicinal use.