The Wiberg bond index and the topological parameters, including the electron density (ρ_r, in a.u.), Laplacian of electron density (∇²ρ_r, in a.u.), the density of potential energy (V_r, in a.u.), the density of kinetic energy (G_r, in a.u.), and the density of total energy (H_r, in a.u.) at the BCPs for the most stable 5-Fu@B₄₀, 5-Fu@[M@B₄₀] and 5-Fu@B₃₉M (M = Mg, Al, Si, Mn, Cu, and Zn) complexes.

Complexes	Bonds	WBI	ρ r	∇2ρr	G r	V r	H r
5-Fu@B40	B25–O2	0.574	0.119	0.468	0.189	−0.262	−0.072
5-Fu@[Mg@B40]	B36–O1	0.613	0.134	0.592	0.232	−0.315	−0.084
5-Fu@[Al@B40]	B26–O1	0.635	0.148	0.685	0.267	−0.363	−0.096
5-Fu@[Si@B40]	B35–O2	0.576	0.120	0.471	0.191	−0.265	−0.073
5-Fu@[Mn@B40]	B7–O2	0.585	0.122	0.494	0.198	−0.272	−0.074
5-Fu@[Cu@B40]	B25–O1	0.648	0.157	0.714	0.284	−0.390	−0.106
5-Fu@[Zn@B40]	B17–O2	0.575	0.120	0.486	0.194	−0.267	−0.073
5-Fu@B39Mg	Mg52–O2	0.237	0.044	0.349	0.074	−0.061	0.013
5-Fu@B39Al	Al40–O2	0.344	0.065	0.437	0.106	−0.103	0.003
5-Fu@B39Si	B17–O2	0.592	0.119	0.506	0.197	−0.267	−0.070
5-Fu@B39Mn	Mn52–O2	0.354	0.055	0.334	0.081	−0.078	0.002
5-Fu@B39Cu	Cu52–O2	0.189	0.081	0.562	0.140	−0.140	0.000
5-Fu@B39Zn	Zn52–O2	0.223	0.070	0.418	0.104	−0.102	0.001