Theoretical structure and vibrational spectra of ciprofloxacin: Density functional theory study

The molecular structure and vibrational spectra of ciprofloxacin(1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid) have been calculated using the different density functional theory (DFT) methods and various basis sets. This paper examines the comparative performance of different DFT methods at various basis sets in predicting molecular and vibrational spectra of ciprofloxacin. The calculation results show that SVWN/LANL2DZ level and SVWN/6-31G level offer the highest certainty to predict the structure and vibrational spectra of ciprofloxacin, respectively.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► First principles studied on the molecular structures and vibration spectra of ciprofloxacin. ► The uniform scaling method was used to improve the calculated frequencies. ► The performance of the different DFT and basis sets were examined. ► SVWN/LANL2DZ level is the best for predicting the structure of ciprofloxacin. ► SVWN/6-31G level is the best for predicting the vibration spectra of ciprofloxacin.