Complexes of Zn(II)–Triazoles with CO₂ and H₂O: Structures, Energetics, and Applications

Abstract

Using a first-principle methodology, we investigate the stable structures of the nonreactive and reactive clusters formed between Zn2+–triazoles ([Zn2+-Tz]) clusters and CO2 and/or H2O. In sum, we characterized two modes of bonding of [Zn2+-Tz] with CO2/H2O: the interaction is established through (i) a covalent bond between Zn2+ of [Zn2+-Tz] and oxygen atoms of CO2 or H2O and (ii) hydrogen bonds through N–H or C–H of [Zn2+-Tz] and oxygen atoms of H2O or CO2, N–H···O. We also identified intramolecular proton transfer processes induced by complexation. Indeed, water drastically changes the shape of the energy profiles of the tautomeric phenomena through strong lowering of the potential barriers to tautomerism. The comparison to [Zn2+-Im] subunits formed with Zn2+ and imidazole shows that the efficiency of Tz-based compounds for CO2 capture and uptake is due to the incorporation of more accessible nitrogen donor sites in Tzs compared to imidazoles. Since [Zn2+-Tz] clusters are subunits of an organometallic nanoporous materials and Zn–proteins, our data are useful for deriving force fields for macromolecular simulations of these materials. Our work also suggests the consideration of traces of water to better model the CO2 sequestration and reactivity on macromolecular entities such as pores or active sites.

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.…”

“…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. 68–71…”

Unraveling the Structure and Binding Energy of Adsorbed CO2/H2O on Amine Sorbents

“…The presence of H 2 O could lead to the formation of hydronium carbamate according to eq . ,,− Hydronium has also been proposed to play an important role in a number of systems involving CO 2 and H 2 O. ,, The simulated infrared spectrum of hydronium carbamate, TEPA 2 -N (1) H­(H 3 O + NCOO – ), in Figure b shows that both asymmetric ν a (OCO – ) vibration and symmetric ν s (OCO – ) vibration, characteristic bands for the carbamate structure, in the simulated spectrum of hydronium carbamate fall in the same range of ammonium carbamate in Figure a. The formation of hydrogen bonding between hydronium ion and carbamate ion led to the ν­(O–H + ··· – OCO) vibration at 2827 cm –1 for TEPA 2 -N (1) H­(H 3 O + NCOO – ) in Figure b and at 2470 cm –1 for TEPA 2 -N (3) (H 3 O + NCOO – ) + (H 2 O) 3 in Figure a.…”

DFT mechanistic study of the chemical fixation of CO2 by aziridine derivatives

“…In addition, solvent effects were examined using self‐consistent reaction field theory or by considering explicitly a water molecule closely interacting with the reactants and TSs. Indeed, previous theoretical and experimental works showed that the closest solvent molecule to the reactants plays the most important role in solvents 53–57 . The case of NaBr as a green catalyst is also examined.…”