Synthesis of Silver– 4,4’-diaminodiphenyl –Cyclodextrin Nanomaterials and pH Dependent Characteristics of 4,4’-diaminodiphenyl –Cyclodextrin Inclusion Complexes

Abstract

The spectral characteristics of 4,4’-diaminodiphenyl (benzidine, DADP) in various solvents, and in the presence of α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD) at pH~3 and pH~7, were investigated using UV–visible, fluorescence, time-resolved fluorescence measurements, and PM3 computational methods. Ag:DADP:CD nanomaterials were synthesized and characterized by SEM, DSC, FTIR, 1H NMR and XRD techniques. Both pH conditions, DADP exhibited distinct absorption and emission shifts upon complexation with α-CD and β-CD. DADP showed a single broad emission band in all solvents, and CD solutions indicates the presence of twisted intramolecular charge transfer (TICT) in the DADP molecule. The fluorescence lifetimes of the inclusion complexes were greater than that of free DADP. In the DADP molecule, both the vertical and horizontal bond lengths between the amino and hydroxy groups are smaller than the β-CD cavity size. SEM–EDX data confirmed the presence of 5.5% silver in the nanomaterials.