Study on the interaction of Basic Violet 2 with hydroxypropyl-β-cyclodextrin

The formation of the inclusion complexes of Basic Violet 2 (New Fuchsin) with hydroxypropyl-β-cyclodextrin (HP-β-CD) was studied by UV–Vis absorption and fluorescence spectroscopy. The binding constants of the inclusion complexes, KB, were obtained considering the maximum shift of the absorption spectra, the absorption areas deconvoluted as the sum of two gaussian constituents, the relative fluorescence quantum yield and the fluorescence maximum shift. The values achieved were 2.7 × 103 M−1, 0.95 × 103 M−1 and 2.8 × 103 M−1, 2.2 × 103 M−1, respectively. Ab-initio calculations using B3LYP/6-31G level of approach and the natural bond orbital (NBO) analysis were performed to gain a deeper understanding of the inclusion phenomena. The result showed a high complexation in aqueous media.

► Hydroxypropyl-b-Cyclodextrin (HP-β-CD) includes Basic Violet 2 (NF). ► NF–HP-β-CD inclusion complex was studied by absorption and emission spectroscopy. ► The equilibrium constant was around 2×103 M−1 and confirmed by theoretical calculi. ► B3LYP/6-31G Ab-initio and NBO analysis confirm the inclusion phenomena.