Ab Initio and DFT Studies on CO₂ Interacting with Zn^q+–Imidazole (q=0, 1, 2) Complexes: Prediction of Charge Transfer through σ‐ or π‐Type Models

Abstract

Using first-principles methodologies, the equilibrium structures and the relative stability of CO2 @[Zn(q+) Im] (where q=0, 1, 2; Im=imidazole) complexes are studied to understand the nature of the interactions between the CO2 and Zn(q+) -imidazole entities. These complexes are considered as prototype models mimicking the interactions of CO2 with these subunits of zeolitic imidazolate frameworks or Zn enzymes. These computations are performed using both ab initio calculations and density functional theory. Dispersion effects accounting for long-range interactions are considered. Solvent (water) effects were also considered using a polarizable continuum model approach. Natural bond orbital, charge, frontier orbital and vibrational analyses clearly reveal the occurrence of charge transfer through covalent and noncovalent interactions. Moreover, it is found that CO2 can adsorb through more favorable π-type stacking as well as σ-type hydrogen-bonding interactions. The inter-monomer interaction potentials show a significant anisotropy that might induce CO2 orientation and site-selectivity effects in porous materials and in active sites of Zn enzymes. Hence, this study provides valuable information about how CO2 adsorption takes place at the microscopic level within zeolitic imidazolate frameworks and biomolecules. These findings might help in understanding the role of such complexes in chemistry, biology and material science for further development of new materials and industrial applications.

Theoretical treatment of IO–X (X = N2, CO, CO2, H2O) complexes

“…This was already established for Zn 0/+/2+ -imidazole and Zn 2+ -triazole complexes either isolated or interacting with CO 2 or H 2 O. [68][69][70][71] We should note that for both types of interactions which participate in the formation of these complexes, we demonstrate that all used ab initio and DFT methods predict a greater stability for the halogen interaction. Indeed, Table 3 shows that the I-bonded complexes are more stable than the respective O-bonded ones.…”

Multicomponent solid forms of the uric acid reabsorption inhibitor lesinurad and cocrystal polymorphs with urea: DFT simulation and solubility study

“…lesinurad, caffeine, nicotinamide and urea) were optimized at the M05-2X/6-311++G** level to study the binding strength of the homo-and heterosynthon dimers using the DFT-based M05-2X functional with the 6-311++G** basis set (Zhao & Truhlar, 2004. Earlier reports reveal that this method is more reliable in predicting the structure and stability of weakly bonded complexes and is in close agreement with the CCSD(T)/CBS approach (Prakash et al 2009(Prakash et al , 2014Boussouf et al, 2015;Boulmene et al, 2016). Binding energies (BEs) of all the dimers were calculated using the supermolecule approach and corrected for basis set superposition error (BSSE) using the counterpoise (CP) procedure suggested by Boys & Bernardi (1970)…”

Encapsulation of anticancer drug doxorubicin inside dendritic macromolecular cavities: First-principles benchmarks

“…[37,38] for instance), providing that no appreciable charge transfer occurs in the excitation process and the monodeterminantal picture is a good zero-order approximation of the electronic wavefunction. Previously, we showed, through comparisons with experiments and to reference post Hartree-Fock methods, that the present theoretical approach is accurate enough to derive the desired properties of this type of complexes [39][40][41][42][43][44].…”