Insights on the interaction of Zn2+ cation with triazoles: Structures, bonding, electronic excitation and applications

Modular Design of Functional Glucose Monomer and Block Co-Polymer toward Stable Zn Anodes

Aqueous Zn batteries employing mildly acidic electrolytes have emerged as promising contenders for safe and cost-effective energy storage solutions. Nevertheless, the intrinsic reversibility of the Zn anode becomes a focal concern due to the involvement of acidic electrolyte, which triggers Zn corrosion and facilitates the deposition of insulating byproducts. Moreover, the unregulated growth of Zn over cycling amplifies the risk of internal short-circuiting, primarily induced by the formation of Zn dendrites. In this study, a class of glucose-derived monomers and a block copolymer are synthesized through a building-block assembly strategy, ultimately leading to uncover the optimal polymer structure that suppresses the Zn corrosion while allowing efficient ion conduction with a substantial contribution from cation transport. Leveraging these advancements, remarkable enhancements are achieved in the realm of Zn reversibility, exemplified by a spectrum of performance metrics, including robust cycling stability without voltage overshoot and short-circuiting during 3000 h of cycling, stable operation at a high depth of charge/discharge of 75% and a high current density, >95% Coulombic efficiency over 2000 cycles, successful translation of the anode improvement to full cell performance. These polymer designs offer a transformative path based on the modular synthesis of polymeric coatings toward highly reversible Zn anode.

Selective adsorption of sulphur dioxide and hydrogen sulphide by metal-organic frameworks

The removal of highly toxic gasses such as SO₂ and H₂S is important in various industrial and environmental applications. Metal organic frameworks (MOFs) are promising candidates for the capture of toxic gases owing to their favorable properties such as high selectivity, moisture stability, thermostability, acid gas resistance, high sorption capacity, and low-cost regenerability. In this study, we perform first principles density functional theory (DFT) and grand-canonical Monte Carlo (GCMC) simulations to investigate the capture of highly toxic gases, SO₂ and H₂S, by the recently designed ZTF and MAF-66 MOFs. Our results indicate that ZTF and MAF-66 show good adsorption performances for SO₂ and H₂S capture. The nature of the interactions between H₂S or SO₂ and the pore surface cavities was examined at the microscopic level. SO₂ is adsorbed on the pore surface through two types of hydrogen bonds, either between O of SO₂ with the closest H of the triazole 5-membred ring or between O of SO₂ with the hydrogen of the amino group. For H₂S inside the pores, the principal interactions between H₂S and surface pores are due to a relatively strong hydrogen bonds established between the nitrogens of the organic part of MOFs and H₂S. Also, we found that these interactions depend on the orientation of SO₂/H₂S inside the pores. Moreover, we have studied the influence of the presence of water and CO₂ on H₂S and SO₂ capture by the ZTF MOF. The present GCMC simulations reveal that the addition of H₂O molecules at low pressure leads to an enhancement of the H₂S adsorption, in agreement with experimental findings. However, the presence of water molecules decreases the adsorption of SO₂ irrespective of the pressure used. Besides, SO₂ adsorption is increased in the presence of a small number of CO₂ molecules, whereas the presence of carbon dioxide in ZTF pores has an unfavorable effect on the capture of H₂S.

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

Iodine monoxide (IO) is an important component of the biogeochemical cycle of iodine. For instance, it is present in the troposphere, where it plays a crucial role in the physical chemical processes involving iodine containing compounds. Here, we present a theoretical study on a series of atmospherically relevant complexes of IO with N₂, CO, CO₂ and H₂O, where their structural and spectroscopic properties and their interaction energies are computed. Calculations are carried out by means of ab initio post Hartree-Fock (RCCSD(T) and RMP2) methods and density functional theory DFT (PBE0 and M05-2X) based approaches with and without the inclusion of dispersion correction. After comparison to RCCSD(T), we highlight the good performance of M05-2X(+D3) DFT in describing the bonding between IO and X (X = N₂, CO, CO₂, H₂O). Moreover, we found that the IO-X (X = N₂, CO, CO₂, H₂O) complexes are formed by non-covalent interactions between the two monomers. In sum, we characterized two types of complexes: I-bonded and O-bonded, where the former is more stable. The atmospheric implications of the present findings are also discussed such as in the formation of the iodine oxide particles (IOPs).

In silico design of a new Zn-triazole based metal-organic framework for CO2 and H2O adsorption

In search for future good adsorbents for CO₂ capture, a nitrogen-rich triazole-type Metal-Organic Framework (MOF) is proposed based on the rational design and theoretical molecular simulations. The structure of the proposed MOF, named Zinc Triazolate based Framework (ZTF), is obtained by replacing the amine-organic linker of MAF-66 by a triazole, and its structural parameters are deduced. We used grand-canonical Monte Carlo (GCMC) simulations based on generic classical force fields to correctly predict the adsorption isotherms of CO₂ and H₂O. For water adsorption in MAF-66 and ZTF, simulations revealed that the strong hydrogen bonding interactions of water with the N atoms of triazole rings of the frameworks are the main driving forces for the high adsorption uptake of water. We also show that the proposed ZTF porous material exhibits exceptional high CO₂ uptake capacity at low pressure, better than MAF-66. Moreover, the nature of the interactions between CO₂ and the MAF-66 and ZTF surface cavities was examined at the microscopic level. Computations show that the interactions occur at two different sites, consisting of Lewis acid-Lewis base interactions and hydrogen bonding, together with obvious electrostatic interactions. In addition, we investigated the influence of the presence of H₂O molecules on the CO₂ adsorption on the ZTF MOF. GCMC simulations reveal that the addition of H₂O molecules leads to an enhancement of the CO₂ adsorption at very low pressures but a reduction of this CO₂ adsorption at higher pressures.

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

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.