Preparation of 3-Anisidine–Cyclodextrin Doped Silver Nanomaterials and Investigation of 3AS–CD Inclusion Complex at Different pH

The spectral properties of the silver–3-anisidine–cyclodextrin (Ag: 3AS: CD) inclusion complex nanomaterials in solution were investigated using UV–visible, steady-state fluorescence, time-resolved fluorescence, SEM, DSC, FTIR, XRD, <sup>1</sup>H NMR, and molecular modeling methods. The distinct spectral changes observed for 3AS upon the addition of CDs at different pH values indicate that the geometries of the resulting inclusion complexes vary with pH. While 3AS exhibits a single emission maximum in solvents and in α-CD, a dual emission is observed in β-CD. The lifetimes of the inclusion complexes were longer than that of the free 3AS molecule. The relatively narrow cavity of α-CD likely restricts the free rotation of the amino or methoxy groups of 3AS, inhibiting ICT-state formation and thereby enhancing the normal emission. The calculated HOMO–LUMO energy gap, total energy, free energy, enthalpy, entropy, dipole moment, and zero-point vibrational energy of the CD: 3AS complex differed significantly from those of the isolated 3AS, α-CD and β-CD molecules, and both the vertical and horizontal bond lengths between the amino and methoxy groups are smaller than the β-CD cavity size confirming the formation of an inclusion complex. SEM images and EDX analysis confirm the presence of silver in the Ag: 3AS: β-CD nanomaterials. In the FTIR spectra, most characteristic peaks diminish or disappear, accompanied by a marked decrease in intensity for the Ag: 3AS: CD nanocomplexes, suggesting strong interactions between 3AS and nano silver. The <sup>1</sup>H NMR chemical shifts of 3AS protons move both upfield and downfield indicating restricted mobility and strong host–guest interactions within the nano Ag–CD matrix.