Spectroscopic and structural studies of the first complex formed between salinomycin and organic amine

For the first time, the crystalline complex of salinomycin with benzylamine was obtained and its molecular structure was studied using single crystal X-ray diffraction, FT-IR, H-1 NMR,C-13 NMR, 2D NMR and ESI MS methods. These studies provided evidence that the proton from the carboxylic group of salinomycin (SAL) is transferred to the amine group of benzylamine (BnA) forming the host-guest complex (SAL-BnA). It was shown that the SAL-BnA complex both in solid state and in chloroform solution is stabilized by the intramolecular O-H center dot center dot center dot O hydrogen bonds and also by the intermolecular hydrogen bonding interactions of the carboxylate, ketone and/or hydroxyl groups of SAL with water molecules present in the investigated system. The solvated acetonitrile molecules are additionally located in the voids between the SAL-BnA complex molecules in the crystal structure, while water molecules involved in the dihydrated crystalline SAL-BnA complex partially move into the solvent upon dissolution in chloroform. (C) 2016 Elsevier B.V. All rights reserved.