Halogen bonds resemble hydrogen bonds in many aspects. How do the properties of halogen bonds change when confined to nanoregion? In order to explore this, we have encapsulated a halogen bonded complex, CH3Br center dot center dot center dot NH3 inside C-60 fullerene and studied their properties using density functional theory and quantum theory of atoms in molecule. Our findings show that the geometry of CH3Br center dot center dot center dot NH3 complex is appreciably bent inside C-60, interaction becomes covalent with larger interaction energy, unlike free CH3Br center dot center dot center dot NH3 complex, which is linear with closed shell interaction. Thus, the halogen bonded complexes show quite different properties at nanoscale. (C) 2016 Elsevier B.V. All rights reserved.