UVRR spectroscopic studies of valinomycin complex formation in different solvents

We investigated the complexation of valinomycin (VM) in different solvent environments with the aid of the UVRR spectroscopy. By probing the 206.5 and 229 nm excited Raman spectra, we showed that new bands are observed around 1700 and 1290 cm−1. We assigned the 1700 cm−1 band to the hydrogen bonded ester carbonyl stretching vibration. In a polar solvent, VM-K+ complexation shows significant intensity changes in amide and ester carbonyl stretching region. Because of the small amount of conformational interconversion, complexation has a negligible effect on other band intensities including, the amide III, CαH, and amide II. We also showed the effects of the solvent polarity on the solution conformation of VM.