Stepwise pesudopolyrotaxane nanostructure formation from supramolecular self-assembly by inclusion complexation of fast violet B with α- and β-cyclodextrins

The current work deals with fast violet B (FVB) and cyclodextrins (α-CD and β-CD) inclusion complex into pesudopolyrotaxane nanorod by supramolecular self-assembly. FVB/α-CD forms 2:2 from 1:1 and FVB/β-CD forms 1:2 from 1:1 inclusion complexes, which further self assembled to form nanorod and nano cluster structures. The nanorods formed through step-by-step process after FVB encapsulation into cyclodextrins nano cavities. Wide angle powder X-ray diffraction exposed the crystallinity of the materials, thermal analysis, Fourier Transform Infrared Spectroscopy (FTIR) and Proton Nuclear Magnetic Resonance spectroscopy (1H NMR and 2D ROESY) confirmed FVB encapsulation into the CDs cavities. Amido functionality of FVB molecule is twisted when it is encapsulated within α-CD and β-CD cavities. Computational studies further divulge that the complex formation is an enthalpy-entropy driven process.