Novel Organostannanes with Assorted Drugs: Synthesis, Spectral, and Potentiometric Studies

Abstract

Here, we report on synthesis of some novel derivatives of dibutyltin dichloride/oxide with assorted drugs containing a labile proton of carboxylic acid or alcohol moiety. Ligands used in these reactions are ampicillin trihydrate (ABP), ibuprofen (BPPA), acetylsalicylic acid (ASA), and acetaminophen (APAP). Characterization and structure elucidation of the complexes was achieved by elemental analysis, infrared spectroscopy and multinuclear (¹H, ¹³C, and ¹¹⁹Sn) NMR spectroscopic studies. Their protonation behavior and stability constants were investigated and corresponding thermodynamic parameters were calculated using pH-potentiometric technique. It was suggested on basis of potentiometric studies that the complexes formed are invariably of 1:2 stoichiometry irrespective of ligand-to-metal ratio. The stability constants represented by log β values at 298 K were found to be in the order: ABP > APAP > BPPA > ASA. The free energy of formation of these complexes has a negative value, which shows that formation of the complexes is a spontaneous process. Also, the negative value of standard enthalpy change indicates that reaction of ligands with metal ion is exothermic and this validates the decrease in the value of log β with increasing temperature. Entropy change is positive which seems to be the driving force for complex formation.

GRAPHICAL ABSTRACT

Keywords:

• Dibutyltin dichloride/oxide
• drugs
• protonation behavior
• stability constants
• pH-potentiometric studies