Inclusion behaviour of Indole-7-Carboxaldehyde inside β-cyclodextrin: A nano cage

Abstract Encapsulation of Indole-7-Carboxaldehyde ( I7C ) inside nano sized cyclodextrin ( α -, β -, γ -) cavities have been investigated by theoretical (PM3, HF, DFT, ONIOM methods) and experimental (UV–VIS, IR spectroscopy) results. β - cyclodextrin ( CD ) provides best trapping ability as its cavity size matches perfectly with the dimension of I7C . It is shown that in two specific orientations ( P , Q ), I7C can be encapsulated inside hydrophobic β- CD cavity by forming 1:1 inclusion complex. Intermolecular hydrogen bonding is observed to play a vital role in this encapsulation process. Present study on complexation mechanism is expected to provide a better knowledge on the reactivity of β- CD as drug carrier.