Enhanced electronic and nonlinear optical responses of C 24 N 24 cavernous nitride fullerene by decoration with first row transition metals; A computational investigation

Improvement of Hydrogen Adsorption on the Simultaneously Decorated Graphene Sheet with Titanium and Palladium Atoms

In this study, a simultaneously decorated graphene sheet with titanium (Ti) and palladium (Pd) atoms is proposed to improve hydrogen adsorption uptake. Density functional theory (DFT) with a DFT-D3 correction dispersion study was applied. Initially, the hydrogen adsorption energy, energy band gap, partial density of state (PDOS), thermal stability, and H2 desorption temperature for Ti-decorated, Pd-decorated, and Ti-Pd-decorated graphene sheets were investigated. Clustering formation for the Ti-decorated graphene sheet was examined in detail. Grand canonical Monte Carlo (GCMC) simulation was applied to examine the hydrogen adsorption isotherm. Simulation results showed that the hydrogen adsorption energy and desorption temperature of the Ti-decorated graphene sheet are -0.61 eV and 765.4 K, respectively, which are significantly higher than those of the Pd-decorated graphene sheet (-0.108 eV and 135.5 K). However, Ti atoms form clusters when their distances from each other are less than 6 Å. Inserting adaptable metal atoms such as Pd into the Ti-decorated graphene adjusts the hydrogen adsorption energy to -0.544 eV and the desorption temperature to 627.4 K. In addition, the values of Gibbs free energy changes (ΔG) of metal adsorption showed that the Ti-Pd graphene sheet has good stability at different temperatures. Calculated hydrogen adsorption isotherm using the GCMC method approved the suitable performance of the Ti-Pd-decorated graphene sheet for hydrogen adsorption. At the pressure of 60 bar and temperature of 298 K, the hydrogen adsorption content increases from 1.49 wt % on the Ti-decorated graphene sheet with cluster to 2.06 wt % on the Ti-Pd-decorated graphene sheet. Finally, Ti-Pd-decorated graphene sheet was proposed as a novel adsorbent in the hydrogen storage industry.

In-silico and in-detail experimental interaction studies of new antitumor Zn(II) complex with CT-DNA and serum albumin

In this study, a novel Zn(II) complex with the formula [Zn(pyrr-ac)2] (pyrr-ac: pyrrolidineacetate) was synthesized and characterized through molar conductivity, elemental analysis, 1H Nuclear Magnetic Resonance (1H NMR), UV-Visible spectroscopy, and Fourier transform infrared (FT-IR) methods. B3LYP level of DFT method along with aug-cc-pVTZ-PP/6-311G(d,p) basis set was utilized to perform the geometry optimization and HOMO-LUMO analysis. In addition, MEP, NLO and NBO computations were also performed at the same level of theory. In vitro antitumor activity of the mentioned complex on leukemia cell line, K562, was investigated using the MTT assay which surprisingly revealed the effective antitumor activity of the studied zinc complex. Interaction of this compound with biological macromolecules viz., CT-DNA and BSA was studied via different spectroscopic methods. The results of fluorescence experiment displayed that the metal complex binds to both macromolecules through hydrogen bond (H-bond) and van der Waals (vdW) forces. UV-Vis tests indicated a decline in the absorption spectra of CT-DNA/BSA in the presence of the compound. The interaction was further corroborated for CT-DNA via gel electrophoresis, CD spectroscopy and viscosity experiments and for BSA using CD spectroscopy. Furthermore, molecular docking simulation was done to evaluate the nature of interaction between the aforementioned zinc complex and CT-DNA/BSA. These results were in agreement with experimental findings and demonstrated that the main interaction is hydrogen bonding. The above type of investigations may provide a pathway through which zinc complexes join the anticancer category.[Figure: see text]The in-silico and in-vitro results confirm that the newly made [Zn(pyrr-ac)2] complex interacts with CT-DNA than BSA.Communicated by Ramaswamy H. Sarma.

Efficient delivery of anticancer 5-fluorouracil drug by alkaline earth metal functionalized porphyrin-like porous fullerenes: A DFT study

Finding and developing effective targeted drug delivery systems has emerged as an attractive approach for treating a wide range of diseases. In the present study, the potential of alkaline earth metal functionalized porphyrin-like porous C₂₄N₂₄ fullerenes for delivering 5-fluorouracil (5FU) anticancer drug is assessed using density functional theory calculations. The goal is to evaluate how the addition of alkaline earth metals to C₂₄N₂₄ enhances the adsorption capabilities of this system towards 5FU drug. The adsorption energies and charge transfers are determined in order to evaluate the strength of the interaction between the 5FU and fullerene surfaces. According to the results, adding alkaline earth metals increases the drug's adsorption energy on the C₂₄N₂₄ fullerene. In all cases, the drug molecule interacts with the metal atom through its CO group. Furthermore, the adsorption strength of the 5FU increases with metal atom size (Ca > Mg > Be), which is connected to the polarizability of these atoms. The adsorption energies of 5FU are shown to be highly sensitive on solvent effects and the acidity of the environment. The adsorption strength of 5FU decreases within the solvent (water), allowing it to be released more easily. The moderate adsorption energies and short desorption times of 5FU imply that it is reversibly adsorbed on the functionalized fullerenes.

Transition metalides based on facially polarized all-cis-1,2,3,4,5,6-hexafluorocyclohexane - a new class of high performance second order nonlinear optical materials

Continuous attempts are being made to discover new approaches to design materials with extraordinary nonlinear optical responses. Herein, for the first time, we report the geometric, electronic, and nonlinear optical properties of novel Janus transition metalides AM-J-TM (where AM = Li, Na and K, and TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) containing alkali metals as a source of excess electrons for transition metals to generate metalides. The Janus organic complexant used for the study is all cis 1,2,3,4,5,6-hexafluorocyclohexane F₆C₆H₆ (J). These complexes contain the unique involvement of alkali metals (AM = Li, Na and K) as a source of excess electrons, which significantly affects the hyperpolarizability values of the resulting transition metalides. The NBO analysis reveals the charge transfer from alkali metals to the transition metals, thereby confirming the metalide behavior of the complexes. Moreover, the metalide nature of these complexes is validated through frontier molecular orbital (FMO) analysis. The values of interaction energies, vertical ionization potential (VIP) and vertical electron affinity (VEA) illustrate the stability of the metalide complexes. Ultimately, the hyperpolarizability values confirm the excellent nonlinear optical response of the designed transition metalides. The remarkable static first hyperpolarizability (β₀) response up to 4 × 10⁸ a.u. is observed for complexes of vanadium. Similarly, the complexes of AM-J-Mn and Li/Na-J-Sc show significantly high NLO response. These compounds besides providing a new entry into excess electron compounds will also pave the way for the design and synthesis of further novel NLO materials.

Ca functionalized N-doped porphyrin-like porous C60 as an efficient material for storage of molecular hydrogen

It is widely known that decorating metal atoms on defective carbon nanomaterials is a useful approach to enhance the hydrogen storage capacity of these systems. Herein, density functional theory calculations are used to determine the H₂ storage capacity of Ca functionalized nitrogen incorporated defective C₆₀ fullerenes (Ca₆C₂₄N₂₄). The strong binding, uniform distribution, and significant positive charges of the Ca atoms make this system effective material for storage of H₂. Ca₆C₂₄N₂₄ may adsorb a maximum of 6 hydrogen molecules per Ca atom, yielding a total gravimetric density of 7.7 wt %.

Catalytic oxidation of CH4 into CH3OH using C24N24-supported single-atom catalyst

Methanol is a promising source that can replace non-renewable petroleum energy. Therefore, it is of great importance to oxidize the methane into methanol because methane is not easy to transport although its huge reserves. The stability between TM (Ti, V) atoms and C₂₄N₂₄ is firstly studied through DFT calculations. The results show that the binding energy between TM and C₂₄N₂₄(Ti@C₂₄N₂₄ =  - 9.0 eV, V@C₂₄N₂₄ =  - 8.0 eV) is more negative than its cohesive energy (Ti =  - 5.6 eV, V =  - 5.6 eV), indicating TM@C₂₄N₂₄ possess good stability. On this basis, the oxidation process of methane to methanol is further studied on the TM@C₂₄N₂₄ single-atom catalysis using N₂O as the oxidant. The results show that N₂O is firstly adsorbed on TM@C₂₄N₂₄, and then directly decomposed into N₂ and O_ads. N₂ is released and only O_ads is adsorbed on C₂₄N₂₄ as active oxygen for the following catalytic methane oxidation to methanol process. The process includes two steps: (1) CH₄ + O_ads → CH₃* + OH*, the reaction barriers in this process are 1.2 eV (Ti) and 1.5 eV (V); (2) CH₃* + OH* → CH₃OH, the reaction barriers are 1.8 eV (Ti) and 1.8 eV (V) in this step. Finally, the obtained CH₃OH molecule will leave the surface of TM@C₂₄N₂₄ single-atom catalyst and the energy required for this step is 1.4 eV (Ti) and 1.0 eV (V), respectively. These findings provide theoretical guidance for the catalytic oxidation of CH₄ to CH₃OH using TM (Ti,V)@C₂₄N₂₄ single-atom catalysts.

Reversible CO2 storage and efficient separation using Ca decorated porphyrin-like porous C24N24 fullerene: a DFT study

The search for novel materials for effective storage and separation of CO₂ molecules is a critical issue for eliminating or lowering this harmful greenhouse gas. In this paper, we investigate the potential application of a porphyrin-like porous fullerene (C₂₄N₂₄) as a promising material for CO₂ storage and separation using thorough density functional theory calculations. The results show that CO₂ is physisorbed on bare C₂₄N₂₄, implying that this material cannot be used for efficient CO₂ storage. Coating C₂₄N₂₄ with Ca atoms, on the other hand, can greatly improve the adsorption strength of CO₂ molecules due to polarization and charge-transfer effects. Furthermore, the average adsorption energy for each of the maximum 24 absorbed CO₂ molecules on the fully decorated Ca₆C₂₄N₂₄ fullerene is −0.40 eV, which fulfills the requirement needed for efficient CO₂ storage (−0.40 to −0.80 eV). The Ca coated C₂₄N₂₄ fullerene also have a strong potential for CO₂ separation from CO₂/H₂, CO₂/CH₄, and CO₂/N₂ mixtures.

Using dispersion-corrected DFT calculations, the potential application of a porphyrin-like porous fullerene (C₂₄N₂₄) as an efficient material for CO₂ storage and separation was investigated.

Ngn (Ng= Ne, Ar, Kr, Xe, and Rn; n=1, 2) encapsulated porphyrin-like porous C24N24 fullerene: A quantum chemical study

This study focused on the theoretical viability of Ng_n@C₂₄N₂₄ (Ng = Ne, Ar, Kr, Xe, and Rn; n = 1, 2) complexes using density functional theory at the computational level of ωB97X-D/def2-TZVP. Thermodynamic and kinetic stabilities of these complexes have been evaluated by calculating the interaction energy of Ng atoms encapsulated C₂₄N₂₄ cage (ΔE_int), and the corresponding dissociation energy barrier (ΔG^‡), respectively. The obtained results predict that although these complexes are thermodynamically unstable compared to their dissociation into free Ng atoms and the bare C₂₄N₂₄ cage, but once formed, they are protected by the activation energy barrier of the corresponding dissociation process. Furthermore, natural population analysis (NPA) and topological analysis of the electron density have been employed to investigate the nature of Ng-Ng and Ng-cage interactions. The results demonstrate that these interactions are highly significant compared to similar cases in the free state; and the amounts of energy of the interaction gradually increases as the Ng atom becomes heavier. Surprisingly in the Kr₂@C₂₄N₂₄ complex the Kr-Kr bond is somewhat covalent in nature relative to non-bonded interaction in Kr₂ free dimer.

Efficient hydrogen storage on Al decorated C24N24: a DFT study

Hydrogen storage on Al-decorated C24N24 is explored by the dispersion corrected DFT calculations. Each Al site in the Al6C24N24 cluster can adsorb up to five H2 molecules, with an average adsorption energy of −0.30 eV.