Density Functional Theoretical Calculations Research Articles

Cu-induced interface engineering of NiCu/Ni3N heterostructures for enhanced alkaline hydrogen oxidation reaction

Constructing well-defined interfaces in catalysts is a highly effective method to accelerate reactions with multiple intermediates. In this study, we developed a heterostructure catalyst combining fcc NiCu and hcp Ni3N, aiming at achieving superior performance in alkaline hydrogen electrocatalysis. The NiCu/Ni3N not only overcomes the inadequate hydroxyl binding energy performance of NiCu alloys but also solves the problems of insufficient active sites found in most Ni/Ni3N. Experimental results and density functional theoretical calculations reveal that the formation of heterostructure significantly depends on the amount of Cu. This approach effectively prevents the side effects of increased catalyst particle size, typically resulting from the high temperatures and prolonged reaction times required for conventional synthesis of Ni/Ni3N. The interface of this heterostructure induces a distinctive overlapping effect that enhances the adsorption of water and lowers the energy barrier for the rate-determining step. The NiCu/Ni3N catalyst shows an impressive activity of 71.8 mA mg−1 at an overpotential of 50 mV, a 14.7 times efficiency enhancement compared to pure Ni and comparable to that of low-loaded commercial Pt/C. This research highlights the potential of NiCu/Ni3N in advancing catalyst development.

Metal-free N, P-Codoped Carbon for Syngas Production with Tunable Composition via CO2 Electrolysis: Addressing the Competition Between CO2 Reduction and H2 Evolution.

Electroreduction of carbon dioxide into value-added fine chemicals is a promising technique to realize the carbon cycle. Recently, metal-free heteroatom doped carbons are proposed as promising cost-effective electrocatalysts for CO2 reduction reaction (CO2RR). However, the lack of understanding of the active site prevents the realization of a high-performance electrocatalyst for the CO2RR. Herein, we synthesized metal-free N, P co-doped carbons (NPCs) for producing syngas, which is composed of H2 and CO, by CO2 electrolysis using inexpensive bio-based raw materials via simple pyrolysis. The syngas ratio (H2/CO) can be controlled within the high demand range (0.3-4) at low potentials using NPCs by tuning the N and P contents. In comparison with only N doping or P doping, N and P co-doping has a positive impact on improving CO2RR activity. Experimental analysis and density functional theoretical (DFT) calculations revealed that negatively charged C atoms adjacent to N and P atoms are the most favorable active sites for CO2-to-CO conversion compared to pyridinic N on N, P co-doped carbon. Introducing N atoms generates the preferable CO2 adsorption site, and P atoms contribute to decreasing the Gibbs free energy barrier for key *COOH intermediates adsorbed on the negatively charged C atoms.

Interface-Engineering-Induced C-C Coupling for C2H4 Photosynthesis from Atmospheric-Concentration CO2 Reduction.

Producing ethylene (C2H4) from carbon dioxide (CO2) photoreduction under mild conditions is primarily restricted by the difficulty of C-C coupling. Herein, we designed highly active metal atom clusters anchored on semiconductor nanosheet, which established heteroatom sites on the interface to steer C-C coupling, realizing air-concentration CO2 photoreduction into C2H4 in pure water for the first time. As an example, the Pd nanoclusters loaded on ZnO nanosheets are prepared, demonstrated by the X-ray photoelectron spectroscopy and high-angle annular dark-field image. In situ Fourier transform infrared spectroscopy confirms the C-C coupling step over the Pd-ZnO nanosheets, while quasi in situ X-ray photoelectron spectroscopy illustrates the active sites of Pd and Zn atoms on the Pd-ZnO nanosheets during CO2 photoreduction. Density functional theoretical calculations unveil the transition state energy barrier of C-C coupling of CO* and COH* intermediates are only 0.998 eV, hinting the easy C-C coupling to produce C2 fuels. Therefore, the Pd-ZnO nanosheets first realize C2H4 photosynthesis by atmospheric-concentration CO2 reduction with the formation rate of 1.03 μmol g-1 h-1, while the ZnO nanosheets only acquired the carbon monoxide product.

Interface‐Engineering‐Induced C–C Coupling for C2H4 Photosynthesis from Atmospheric‐Concentration CO2 Reduction

Producing ethylene (C2H4) from carbon dioxide (CO2) photoreduction under mild conditions is primarily restricted by the difficulty of C−C coupling. Herein, we designed highly active metal atom clusters anchored on semiconductor nanosheet, which established heteroatom sites on the interface to steer C−C coupling, realizing air‐concentration CO2 photoreduction into C2H4 in pure water for the first time. As an example, the Pd nanoclusters loaded on ZnO nanosheets are prepared, demonstrated by the X‐ray photoelectron spectroscopy and high‐angle annular dark‐field image. In situ Fourier transform infrared spectroscopy confirms the C−C coupling step over the Pd‐ZnO nanosheets, while quasi in situ X‐ray photoelectron spectroscopy illustrates the active sites of Pd and Zn atoms on the Pd‐ZnO nanosheets during CO2 photoreduction. Density functional theoretical calculations unveil the transition state energy barrier of C–C coupling of CO* and COH* intermediates are only 0.998 eV, hinting the easy C–C coupling to produce C2 fuels. Therefore, the Pd‐ZnO nanosheets first realize C2H4 photosynthesis by atmospheric‐concentration CO2 reduction with the formation rate of 1.03 μmol g−1 h−1, while the ZnO nanosheets only acquired the carbon monoxide product.

Precise control of CO2 electroreduction pathways over copper foil through regulating the microenvironment between morphology and crystal plane

Precisely regulating the reaction pathway to produce desired products is a major challenge in electrocatalytic carbon dioxide reduction (eCO2R). In this paper, the wet chemical method was used to adjust the microenvironment between surface morphology and crystal planes of copper-based catalyst to accurately modulate eCO2R pathway, and to achieve the switching between methane (CH4) and ethylene (C2H4) products. In high concentration acidic CuCl2 etching solution for 80 s (Cu-3.6M-80s), the surface of copper foil formed a nano-groove structure with exposed Cu (111), which exhibited remarkable selectivity towards CH4 production. In contrast, when subjected to a low concentration acidic CuCl2 etching solution for 60 s (Cu-1.8M-60s), the copper foil surface exhibited a nanosheet/cube structure exposing Cu (220) and CuCl (111), resulting in the main product switched from CH4 to C2H4 with 57.03 % at −1.0 V versus reversible hydrogen electrode. In-situ attenuated total reflectance infrared and density functional theoretical calculations demonstrated that the Cu-3.6M-80s effectively enriched proton donation and lowered the energy barrier for *CO hydrogenation, while the Cu-1.8M-60s enhanced coverage of *CO intermediates, thereby promoting subsequent C-C coupling. This study presented a promising strategy for modulating the local microenvironment of catalysts, enabling precise control eCO2R pathway to achieve distinct target products.

The Asymmetrical Fe-O-Se Bonds in Fe2O(SeO3)2 Boosting Bifunctional Oxygen Electrocatalytic Performance for Zinc-Air Battery.

Zinc-air batteries (ZABs) have the advantages of high energy density and rich zinc raw materials. It is a low-cost, green and sustainable energy storage device. At present, one of the key technologies that hinder the large-scale application of ZABs is the design and fabrication oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) bifunctional catalysts with excellent performance, especially the non-platinum-based catalysts. Here N-doped carbon-coated Fe-based selenium oxide catalyst Fe2O(SeO3)2/Fe3C@NC with high performance has been fabricated by a one-step pyrolysis and then the electrochemical oxidization. The experimental results confirmed that the existence of Fe-O-Se bonds in Fe2O(SeO3)2 crystal phase of Fe2O(SeO3)2/Fe3C@NC, and the Fe-O-Se bonds could obviously enhance ORR and OER catalytic performance of Fe2O(SeO3)2/Fe3C@NC. Density functional theoretical calculations (DFT) confirmed that the Fe2O(SeO3)2 in Fe2O(SeO3)2/Fe3C@NC had a higher d-band center of Fe atom and a lower p-orbital coupling degree with its own lattice O atom than Fe2O3, which leads to Fe site of Fe2O(SeO3)2 being more likely to adsorb external oxygen intermediates. The Fe-O-Se bonds in Fe2O(SeO3)2 results in the modification of coordination environment of Fe atoms and optimizes the adsorption energy of Fe site for oxygen intermediates. Compared with Fe2O3/Fe3C@NC, the Fe2O(SeO3)2/Fe3C@NC showed the obvious enhancements of ORR/OER catalytic activities with a half-wave potential of 0.91 V for ORR in 0.1 M KOH electrolyte and a low overpotential of 345 mV for OER at 10 mA cm-2 in a 1.0 M KOH electrolyte. The peak power density and specific capacity of Fe2O(SeO3)2/Fe3C@NC-based ZABs are higher than those of Pt/C+RuO2-ZABs. The above results demonstrate that the asymmetrical Fe-O-Se bonds in Fe2O(SeO3)2 plays a key role in improving the bifunctional catalytic activities of ORR/OER for ZABs.

Adsorption of As nano-clusters on different graphene environments

We investigate the adsorption of As nano-clusters on graphene sheets in various environments, including vacancies and anchors with Fe and/or O impurities. To achieve this, we conducted Density-Functional Theoretical (DFT) calculations using the freely distributed SIESTA code. Our findings reveal a direct correlation between the number of vacancies and the adsorption energy, indicating that a higher number of vacancies result in higher adsorption of As-clusters. Additionally, as the Asn-cluster size increases, the adsorption energy decreases. Furthermore, our results suggest that transition metal impurities (such as Fe) serve as effective elements for functionalizing graphene facilitating the adsorption of metallic clusters in this way, making it suitable for applications in wastewater filtration or the purification of toxic elements in water. Finally, we address finite size effects on the adsorption of graphene sheets by perform calculations on graphene flakes of different sizes saturated in different ways.

Incorporation of Mo2C nanoparticles to pollen-derived 3D porous carbon as electrocatalyst for high performance lithium-sulfur batteries

The practical application and development of lithium‑sulfur (LiS) batteries are limited by the slow redox reaction kinetics and shuttle effect of polysulfide lithium (LiPSs). To address these issues, three-dimensional porous carbon (PC, derived from rapeseed pollen) modified with molybdenum carbide (Mo2C) nanoparticles is prepared by a simple and environment-friendly method. On the one hand, the PC-Mo2C host material can facilitate the uniform loading of sulfur and reduce its volume expansion due to its porous carbon structure. On the other hand, it mitigates the shuttle effect by effective chemical adsorption of LiPSs to form strong physical confinement and catalyze the conversion of LiPSs via the aid of the decorated Mo2C nanoparticles. Density functional theoretical calculations also illustrate the Mo2C nanoparticles are capable of inhibiting the shuttle of LiPSs and further improving the cycling stability. The results show that the PC-Mo2C/S electrode exhibits excellent electrochemical performance with high cycle stability (fading rate of 0.066 % per cycle at 0.2C and 0.054 % per cycle at 1C) and outstanding rate capacity (623.2 mAh g−1 at 5C).

Surface Charge Regulation of Graphene by Fluorine and Chlorine Co-Doping for Constructing Ultra-Stable and Large Energy Density Micro-Supercapacitors.

Settling the structure stacking of graphene (G) nanosheets to maintain the high dispersity has been an intense issue to facilitate their practical application in the microelectronics-related devices. Herein, the co-doping of the highest electronegative fluorine (F) and large atomic radius chlorine (Cl) into G via a one-step electrochemical exfoliation protocol isengineered to actualize the ultralong cycling stability for flexible micro-supercapacitors (MSCs). Density functional theoretical calculations unveiled that the F into G can form the "ionic" C─F bond to increase the repulsive force between nanosheets, and the introduction of Cl can enlarge the layer spacing of G as well as increase active sites by accumulating the charge on pore defects. The co-doping of F and Cl generates the strong synergy to achieve high reversible capacitance and sturdy structure stability for G. The as-constructed aqueous gel-based MSC exhibited the superb cycling stability for 500,000 cycles with no capacitance loss and structure stacking. Furthermore, the ionic liquid gel-based MSC demonstrated a high energy density of 113.9mWhcm-3 under high voltage of up to 3.5V. The current work enlightens deep insights into the design and scalable preparation of high-performance co-doped G electrode candidate in the field of flexible microelectronics.

Enhancing photocatalytic degradation of La-BiVO4 through bidirectional regulation of oxygen vacancy and the Mott-Schottky effect

Selective oxidation of photocatalysts is an important reaction, but catalytic capacity and reaction selectivity are usually contradictory. Herein, ultrafine La nanoparticles were introduced to regulate and control the coordination number and environment of Bi, and a catalyst was synthesized with oxygen defects (La-BiVO4) for Rhodamine degradation. Particularly, La-BiVO4 achieved a better reaction rate and selectivity under visible-light irradiation. The results revealed that the degradation rate of Rhodamine by La-BiVO4 reached 94.9 %. Additionally, the characterization and density functional theoretical calculation demonstrated that the Mott-Schottky effect in La-BiVO4 not only changed the BiVO4 electron density and boosted the visible-light-sensitivity, but also hastened the photogenerated charge migration and reduced the energy barrier. This study not only reveals the important role of optimizing single-atom coordination environment in generating free radicals in photocatalytic reactions, but also provides a reasonable degradation strategy for specific pollutants in the environment.

Efficient mineralization of cadmium and arsenic by poorly crystalline CaFe-layered double hydroxide in soil: Performance and mechanism

The co-contamination of arsenic (As) and cadmium (Cd) in the environment is of most concern. In this work, poorly crystalline CaFe-layered double hydroxide (CaFe-LDH) was synthesized with a Ca-to-Fe molar ratio of 4 to ensure effective immobilization of Cd and As in soil. The application of Ca4Fe-LDH in soil remediation demonstrated that the targeted heavy metals gradually mineralized into a relatively stable oxidizable and residual state. At a soil remediation dosage of 1.6%, the availability levels of Cd and As decreased significantly, achieving stabilization efficiencies of 99% and 85.2% respectively. Cd is trapped through isomorphic substitution and dissolution-reprecipitation of calcium (Ca) laminate, resulting in the formation of CdCaFe-LDH mineralization products. As is immobilized through ion exchange with interlayer anions, redox with Fe(III), and Fe-Cd-As complexation. Moreover, the results of the characterization and density functional theoretical (DFT) calculations demonstrate that the CdCaFe-LDH formed by isomeric substitution of Ca for Cd enhanced the adsorption of As on the (110) plane of LDH, indicating that the trap mechanism of Cd and As by Ca4Fe-LDH is synergistically promoted. Overall, the above results prove that mineralization using Ca4Fe-LDH is a promising method to remediate soils combined contaminated by both Cd and As.

Selective hydrogenation of acetylene over Pd/β-Mo2C catalyst: Experimental and theoretical studies

Molybdenum carbide is a promising support to tune the metal reactivity, which originates from the interaction between metal and support. In this work, Pd/β-Mo2C was prepared using a deposition-precipitation method for selective hydrogenation of acetylene. The high temperature calcination is employed to modulate the interaction between Pd and β-Mo2C. The Pd/β-Mo2C catalyst calcined at 600 °C exhibits significant promotion in selective hydrogenation, which shows 100 % acetylene conversion and 81.4 % ethylene selectivity at 160 °C. The activity promotion originates from the enhanced electronic metal-support interaction, which induces a shift of Pd 3d to higher binding energy. Besides, the Pd species become atomically dispersed after calcination. The changes in geometric and electronic structure suppress the formation of Pd hydrides, which consequently inhibits the excessive hydrogenation capacity of Pd. The structure variation also affects the adsorption of ethylene. No strong adsorbed ethylene (di-σ bonded ethylene) can be identified, which is conducive to the improvement of ethylene selectivity. Density functional theoretical (DFT) calculations confirm that Pd on β-Mo2C is positively charged. The desorption energy of C2H4* (0.78 eV) is significantly lower than that of further hydrogenation (1.45 eV), which explains the improved ethylene selectivity of the calcinated catalyst. The present study indicates calcination is an effective method to tune the activity of Pd/β-Mo2C for reactions beyond selective hydrogenation of acetylene.

Broad spectral response of Y-NaBi(MoO4)2@NaYF4:Yb, Tm photocatalysts for efficient degradation of ciprofloxacin: Upconversion mechanism and theoretical calculations

In this work, a novel Y-NaBi(MoO4)2@NaYF4:Yb, Tm composite was successfully synthesized for the first time by hydrothermal method. The lamellar Y-NaBi(MoO4)2 was dispersed on the surface of the hexagonal prism NaYF4:Yb, Tm without aggregation. The composite achieved a broad spectral response. The NaYF4:Yb, Tm absorbed near-infrared light and emitted ultraviolet and visible light by the energy transfer upconversion process. The emitted light was reabsorbed by Y-NaBi(MoO4)2 through the fluorescence resonance energy transfer process. Moreover, the doping of Y3+ ions enhanced the light response capability of the composite. The experimental results revealed that the photocatalytic degradation efficiency of ciprofloxacin (CIP) reached 96.2 % after 180 min of illumination under simulated sunlight. Meanwhile, the degradation pathways and attack sites of CIP were intensively investigated by liquid chromatography-mass spectrometry analysis and density functional theory theoretical calculations. The upconversion process, the separation of photogenerated carriers and rare earth metal ion doping all contributed to the high effective photodegradation. This work provided a new strategy for effective utilization of solar energy for the degradation of emerging pollutants to mitigate environmental pollution.

Water orientation on platinum surfaces controlled by step sites.

In this work, the adsorption structure of deuterated water on the stepped platinum surface is studied under an ultra-high vacuum by using heterodyne-detected sum-frequency generation spectroscopy. On a pristine Pt(553), D2O molecules adsorbed at the step sites act as hydrogen bond (H-bond) donors to the adjacent terrace sites. This ensures the net D-down orientation at the terrace sites away from the steps. In particular, the pre-adsorption of oxygen atoms at the step sites significantly alters the D-down configuration. The oxygen pre-adsorption leads to a spontaneous dissociation of the post-adsorbed water molecules at the step to form hydroxyl (OD) species. Since the hydroxyl at the step acts as a strong H-bond acceptor, D2O at the terrace no longer maintains the D-down configuration and adopts flat-lying configurations, significantly reducing the number of D-down molecules at the terrace. Density-functional theoretical calculations support these pictures. This work demonstrates the critical role of steps in controlling the net orientation of the interfacial water and provides an important reference for future considerations of the reactions at electrochemical interfaces.

Single-Pd-Site Catalyst Induced by Different Dimensional Nitrogen of N-Doping Carbon for Efficient Hydroaminocarbonylation of Alkynes.

The unsaturated amides are traditionally synthesized by acylation of carboxylic acids or hydration of nitrile compounds but are rarely investigated by hydroaminocarbonylation of alkynes using heterogeneous single-metal-site catalysts (HSMSCs). Herein, single-Pd-site catalysts supported on N-doping carbon (NC) with different nitrogen dimensions inherited from corresponding metal-organic-framework precursors are successfully synthesized. 2D NC-supported single-Pd-site (Pd1/NC-2D) exhibited the best performance with near 100% selectivity and 76% yield of acrylamide for acetylene hydroaminocarbonylation with better stability, superior to those of Pd1/NC-3D, single-metal-site/nanoparticle coexisting catalyst, and nanoparticle catalyst. The coordination environment and molecular evolution of the single-Pd-site during the process of acetylene hydroaminocarbonylation on Pd1/NC-2D are detailly illuminated by various characterizations and density functional theoretical calculations (DFT). DFT also showed the energy barrier of rate-determining step on Pd1/NC-2D is lower than that of Pd1/NC-3D. Furthermore, Pd1/NC-2D catalyst illustrated the general applicability of the hydroaminocarbonylation for various alkynes.

A novel visible light-driven oxygen doped C3N4/Bi12O17Cl2/ferrate(VI) system for Bisphenol A degradation: Radical and nonradical pathways

In this study, visible light-activated photocatalyst oxygen-doped C3N4@Bi12O17Cl2 (OCN@BOC) and Fe(VI) coupling system was proposed for the efficient degradation of bisphenol A (BPA). The comprehensive characterization of the OCN@BOC photocatalyst revealed its excellent photogenerated carrier separation rate in heterogeneous structures. The OCN@BOC/Fe(VI)/Vis system exhibited a remarkable BPA removal efficiency of over 84% within 5 min. Comparatively, only 37% and 59% of BPA were degraded by single OCN@BOC and Fe(VI) in 5 min, respectively. Reactive species scavenging experiments, phenyl sulfoxide transformation experiments, and electron paramagnetic resonance experiments confirmed the involvement of superoxide radicals (⋅O2−), singlet oxygen (1O2), as well as iron(V)/iron(IV) (Fe(V)/Fe(IV)) species in the degradation process of BPA. Furthermore, density functional theoretical calculations and identification of intermediates provided insights into the potential degradation mechanism of BPA during these reactions. Additionally, simulation evaluations using an ecological structure activity relationship model demonstrated that the toxicity of BPA to the ecological environment was mitigated during its degradation process. This study presented a novel strategy for removing BPA utilizing visible light photocatalysts, highlighting promising applications for practical water environment remediation with the OCN@BOC/Fe(VI)/Vis system.

Synergistic effect of oxygen vacancies and functionalized ligands selectively enhanced the photocatalytic oxidation of methane to carbon monoxide

The titanium-based metal–organic framework MIL-125(Ti) has been widely investigated in photocatalytic carbon dioxide reduction and water splitting, but rarely studied in photocatalytic methane conversion by employing only water as an oxidant under mild conditions. Simultaneously controlling products with high yield and selectivity is highly challenging in methane conversion. Herein, we develop a series of functionalized titanium metal–organic frameworks via a facile organic ligand exchange process. The abundant Ti3+ active sites induced by oxygen vacancies and functionalized ligands synergistically facilitate the adsorption and activation of methane molecules. The carbon monoxide yield over NH2-MIL-125(Ti) increased to 198.6 μmol·gcat−1·h−1 with a high selectivity of 87.1 % under simulated solar illumination. Combined with in-situ characterizations and density functional theoretical calculations, the results confirmed that Ti3+ active sites induced by oxygen vacancies and amino functional groups synergistically enhanced the photocatalytic conversion of methane and elucidate CH4-to-CO conversion mechanism. This study does not only provide insights into the rational design of metal–organic frameworks with copious oxygen vacancies and functional groups, but also provides some significant cognition for photocatalytic methane conversion.

Stable novel silicon allotropes in space group P2/m with various band gap structures by high-throughput screening

Silicon is the fundamental material for the semiconductor and microelectronics industries, but controlling the electronic band gap structure of diamond-type silicon remains a huge challenge to adapt to growing applications. Here, we have predicated 23 new silicon allotropes in space group P2/m from 279 possible structures by high-throughput screening accompanied by graph and group theory based on random strategy (RG2) code. The mechanical, electronic and optical properties of these structures were studied in detail. These novel silicon allotropes demonstrate various electronic structures, including metal, direct/quasi direct bandgap structure, and indirect bandgap structures. These new silicon allotropes demonstrate various electronic structures, including metal, direct/quasi direct bandgap structure, and indirect bandgap structures. Besides different electronic bandgap structures, all 23 structures exhibit strong absorption in the visible light region and P2/m-15 demonstrates the excellent mechanical properties (Bulk modulus beyond 80 GPa). Based on their nice stability, good mechanical, electronic and optical properties validated by the ab inito molecular dynamics simulation, phonon spectra and density functional theoretical calculations, these predicted silicon allotropes provide not only ideas for the synthesis of new silicon allotropes but also dawn for expanding the application of semiconductor materials.

Substituent Controlled Tunable Fluorescence from Green to Red and pH Stimuli‐Induced Reversible Fluorescence Switching in Triphenylamine–Quinoxaline Derivatives

A series of triphenylamine‐quinoxaline donor‐acceptor (bipolar) compounds (TPA‐QH, TPA‐QMe, TPA‐QCOOH and TPA‐QNO2) with different substituents were synthesized and investigated their fluorescence properties, including stimuli‐induced fluorescence responses in solution and the solid‐state. Single crystal structural analysis revealed non‐planar molecular conformation, substituent controlled intermolecular interactions and molecular packing in the crystal lattice. TPA‐QH, TPA‐QMe, TPA‐QCOOH and TPA‐QNO2 showed tunable solid‐state emission from green to red. TPA‐QH showed strong fluorescence at 487 nm (quantum yield (Φf) = 28.3%) whereas NO2 substituted TPA‐QNO2 exhibited relatively weak fluorescence at 610 nm (Φf = 4.3%). Density functional theoretical (DFT) calculations also indicated reduction of optical bandgap with substituting electron withdrawing group. The donor‐acceptor structure with intramolecular charge transfer (ICT) resulted solvent polarity dependent fluorescence tuning. The presence of acid responsive quinoxaline group was utilized to demonstrate pH‐responsive fluorescence switching and dual state fluorescence was utilized for fabricating rewritable fluorescent platform. Thus, the present study provides a structural insight to develop dual state emissive triphenylamine–quinoxaline based bipolar materials for optoelectronic applications.

Mutual synergistic regulation of chloride anion and cesium cation binding using a new designed macrocyclic multi-functional sites receptor: A case of DFT computational prediction.

The mutual synergistic regulation of the multi-functional sites on a single receptor molecule for ion-binding/recognition is vital for the new receptor design and needs to be well explored from experiment and theory. In this work, a new macrocyclic ion receptor (BEBUR) with three functional zones, including two ether holes and one biurea groups, is designed expecting to mutually enhance the ion-binding performance. The binding behaviors of BEBUR mainly for Cl- and Cs+ are deeply investigated by using density functional theoretical calculations. It is found that Cl-/Cs+ binding can be mutually enhanced and synergistically regulated via corresponding conformational changes of the receptor, well reflecting an electrical complementary matching and mutual reinforcement effect. Moreover, solvent effect calculations indicate that BEBUR may be an excellent candidate structure for Cl--binding with the enhancement of counter ion (Cs+) in water and toluene. In addition, visualization of intermolecular noncovalent interaction is used for analysis on the nature of the binding interactions between receptor and ions.