Spectroscopic, crystallographic and theoretical studies of lasalocid complex with ammonia and benzylamine

• New Lasalocid complexes were synthesized.
• Lasalocid is a useful ligand for complexation of NH4+ and benzylamine.
• The crystal structure of the complexes were studied.
• Structures of Lasalocid complexes were visualised using DFT method.

A natural antibiotic – Lasalocid is able to form stable complexes with ammonia and organic amines. New complexes of lasalocid with benzylamine and ammonia were obtained in the crystal forms and studied using X-ray, FT-IR, 1H NMR, 13C NMR and DFT methods. These studies have shown that in both complexes the proton is transferred from the carboxylic group to the amine group with the formation of a pseudo-cyclic structure of lasalocid anion complexing the protonated amine or NH4+ cation. The spectroscopic and DFT studies demonstrated that the structure of the complex formed between Lasalocid and benzylamine in the solid is also conserved in the solution and gas phase. In contrast, the structure of the complex formed between lasalocid and ammonium cation found in the solid state undergoes dissociation in chloroform solution accompanied with a change in the coordination form of the NH4+ cation.

The presence of band at 1684 cm–1 and 1401 cm–1 present in the FT-IR spectrum of crystalline complex formed between ionophore antibiotic lasalocid acid and ammonia are no longer observed in chloroform solution. This phenomenon is accompanied by a change in the coordination geometry of NH4+ cation.Figure optionsDownload as PowerPoint slide