A theoretical study on the interaction of [Al(H2O)6]3+ and [Mg(H2O)6]2+ cations with fullerene (C60), coronene and benzene π-systems

Structural Properties and Reactive Site Selectivity of Some Transition Metal Complexes of 2,2′(1E,1′E)-(ethane-1,2-diylbis(azan-1-yl-1-ylidene))bis(phenylmethan-1-yl-1-ylidene)dibenzoic Acid: DFT, Conceptual DFT, QTAIM, and MEP Studies

“…In the present study, topological analyses of the electron density and its Laplacian have been performed at bond critical points. Large ρ ( r ) values and ∇ 2 ρ ( r ) < 0 indicate polar and nonpolar covalent bonding interactions, whereas small ρ ( r ) values and ∇ 2 ρ ( r ) > 0 indicate closed-shell interactions [29]. Generally, ρ ( r ) is greater than 0.20 au for covalent bonding interactions and less than 0.10 au for closed-shell interactions [29].…”

“…Large ρ ( r ) values and ∇ 2 ρ ( r ) < 0 indicate polar and nonpolar covalent bonding interactions, whereas small ρ ( r ) values and ∇ 2 ρ ( r ) > 0 indicate closed-shell interactions [29]. Generally, ρ ( r ) is greater than 0.20 au for covalent bonding interactions and less than 0.10 au for closed-shell interactions [29]. The values of ∇ 2 ρ ( r ) and – G ( r )/ V ( r ) were also used to characterize the bonding interactions in the complexes of EDA2BB investigated.…”

“…Generally, G ( r ) is the kinetic energy density at the BCP (always positive), and V ( r ) is the potential energy density at the BCP (always negative) [30]. When ∇ 2 ρ ( r ) > 0 and – G ( r )/V ( r ) > 1, the interactions are noncovalent, whereas when ∇ 2 ρ ( r ) > 0 and 0.5 < − G ( r )/ V ( r ) < 1, the interactions are partially or partly covalent [29]. …”

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“…By using AIM theory the ρ, HBCP, VBCP, GBCP, and ∇ 2 ρ(r), at the bond critical point of 8-HQ drug with B12N12 and Cu&B12N12, Ni&B12N12 nanocage complexes are calculated and outcomes are reported in Table 3. Based on the AIM theory, the strong covalent bond is indicated with ∇ 2 ρ(r) <0 and HBCP<0 values, the strong electrostatic bond is displayed with ∇ 2 ρ(r) >0 and HBCP>0 values, and partially covalent bond is determined with HBCP<0 and ∇ 2 ρ(r) >0 values [63][64][65]. The calculated results of Table 3 revealed that the values of ∇ 2 ρ(r) and HBCP for all adsorption models except the C-a model are positive and negative, respectively.…”

Corrosion Inhibition of Aluminium in Gas and Acid Media by Some Chalcone-Based N-(3-Aminopropyl)Imidazoles: TD-DFT-Based FMO, Conceptual DFT, QTAIM and EDA Studies

“…The values of ∇ 2 ρ(r) and −G(r)/V(r) were also used to characterize the bonding interactions in the compounds studied. Generally, G(r) is the kinetic Computational Chemistry energy density at the BCP (always positive) and V(r) is the potential energy density at the BCP (always negative) [43] When ∇ 2 ρ(r) > 0 and −G(r)/V(r) > 1, the interactions are noncovalent, whereas when ∇ 2 ρ(r) > 0 and 0.5 < −G(r)/V(r) < 1, the interactions are partially or partly covalent [44]. Based on the popular equation formulated by Espinosa [45] (E int = 0.5 V(r)), for estimating interatomic noncovalent bond interactions, selected bond interaction energies were calculated accordingly.…”