The interaction was more stable in the π-type activation TS1, as indicated by the total interaction energy, primarily driven by the decrease in Pauli repulsion forces between the indole and trans-crotonophenone (Figure ). Following, the energetic components accounting for the overall stabilisation interaction between the O-and π-type activated trans-crotonophenone and I 2 catalyst were evaluated. Despite the π-type activated interaction displaying a significantly larger repulsive energy component, the interaction exhibited higher stability than the O-activation mode. The remaining energetic components, particularly the electrostatic, exchange and polarisation components, were found to be more stable within the π-type activated interaction, contributing to the overall stability of the stabilisation interaction. Additionally, the relatively large repulsive energy component in the π-type activated interaction can be attributed to the slightly covalent nature of the interaction between the π-type activated trans-crotonophenone and I 2 catalyst. In contrast to the other monodentate catalyst under investigation, CAT4, the LMO-EDA analysis of the stabilisation interaction between CAT4 and the trans-crotonophenone substrate demonstrated that its preference for the O-activation mode is solely governed by the electrostatic and repulsive energy components (Figure ).