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

- Equivalent size of Indole-7-Carboxaldehyde (I7C) is responsible for encapsulation in α, β, γ cyclodextrin nano cavities.
- β-CD shows better ability to trap I7C inside its nano cage by forming 1:1 inclusion complex.
- Intermolecular hydrogen bonding (IerHB) interaction plays a vital role in encapsulation process.
- In I7C: β-CD complex existence of IerHB is established through NBO, FTIR, UV-VIS Analysis.
- Theoretical and experimental results confirm I7C: β-CD inclusion complex.

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.