Heterofission, as the conversion mechanism of a singlet excitation on one chromophore to two triplet excitations on two different chromophores, has been known to play imperative roles to boost the efficiency of photovoltaics. Most recently, the heterofission mechanism has been proposed to explain the room temperature phosphorescence (RTP) of organic materials in the form of host/guest (H/G) systems. Herein, the heterofission-induced RTP in the H/G systems is thoroughly investigated with the help of optimally tuned range-separated hybrid functionals (OT-RSHs). Several experimentally known ultralong RTP H/G systems have been considered as working models. For reliable prediction of the energy level matching criteria for the heterofission-induced RTP in these systems, we have proposed and validated variants of the OT-RSHs, their counterparts based on the linear-response and state-specific formalisms within the polarizable continuum model with both the equilibrium and nonequilibrium solvation regimes, and their screened versions accounting for the screening effects through the scalar dielectric constant. In this line, we scrutinize the role of the related ingredients including the underlying density functional approximations, short-range (α) and long-range Hartree–Fock (HF) exchange, and range-separation parameter. Perusing the results reveals that a particular compromise among the involved parameters is needed for well describing the heterofission-induced RTP. Accordingly, the full time-dependent density functional theory computations in the gas phase using the Perdew–Burke–Ernzerhof (PBE)-based OT-RSH (α = 0.0) with the correct asymptotic behavior in the long-range limit as the best performer are preferred. The proposed method also outperforms the standard RSHs with the default parameters, screened-exchange models, and conventional hybrids with both fixed and interelectronic distance-dependent HF exchange. Lastly, the applicability of our developed approximation is put into broader perspective, where it has been used for computational design of several H/G systems as promising candidates prone to be utilized in heterofission-induced RTP materials. We envisage that the recommended OT-RSH in this study can function as an affordable method for both computational modeling of heterofission-induced RTP and verifying the related experimental observations.
{"title":"Heterofission-induced room temperature phosphorescence from range-separated hybrids: in search of the qualified blending components","authors":"Fatemeh Vaziri Alamdarloo, Mojtaba Alipour","doi":"10.1039/d4cp04643a","DOIUrl":"https://doi.org/10.1039/d4cp04643a","url":null,"abstract":"Heterofission, as the conversion mechanism of a singlet excitation on one chromophore to two triplet excitations on two different chromophores, has been known to play imperative roles to boost the efficiency of photovoltaics. Most recently, the heterofission mechanism has been proposed to explain the room temperature phosphorescence (RTP) of organic materials in the form of host/guest (H/G) systems. Herein, the heterofission-induced RTP in the H/G systems is thoroughly investigated with the help of optimally tuned range-separated hybrid functionals (OT-RSHs). Several experimentally known ultralong RTP H/G systems have been considered as working models. For reliable prediction of the energy level matching criteria for the heterofission-induced RTP in these systems, we have proposed and validated variants of the OT-RSHs, their counterparts based on the linear-response and state-specific formalisms within the polarizable continuum model with both the equilibrium and nonequilibrium solvation regimes, and their screened versions accounting for the screening effects through the scalar dielectric constant. In this line, we scrutinize the role of the related ingredients including the underlying density functional approximations, short-range (<em>α</em>) and long-range Hartree–Fock (HF) exchange, and range-separation parameter. Perusing the results reveals that a particular compromise among the involved parameters is needed for well describing the heterofission-induced RTP. Accordingly, the full time-dependent density functional theory computations in the gas phase using the Perdew–Burke–Ernzerhof (PBE)-based OT-RSH (<em>α</em> = 0.0) with the correct asymptotic behavior in the long-range limit as the best performer are preferred. The proposed method also outperforms the standard RSHs with the default parameters, screened-exchange models, and conventional hybrids with both fixed and interelectronic distance-dependent HF exchange. Lastly, the applicability of our developed approximation is put into broader perspective, where it has been used for computational design of several H/G systems as promising candidates prone to be utilized in heterofission-induced RTP materials. We envisage that the recommended OT-RSH in this study can function as an affordable method for both computational modeling of heterofission-induced RTP and verifying the related experimental observations.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"52 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigates the square-octagon lattice electronic properties and quantum capacitance under various external parameters, including hopping amplitudes, magnetic flux, and on-site Coulomb repulsion (OSCRI) by using the Hubbard model (HM) and Green function. The analysis reveals that the lattice can exhibit tunable electronic behaviors, transitioning between semiconducting, metallic, and insulating states by adjusting the hopping parameter ratio t2/t1. Specifically, for t2=t1 and t2=3t1, the material remains semiconducting, while for t2=2t1, it behaves as a metal. The application of magnetic flux reduces the band gap for t2=t1 and t2=3t1 while increasing it for t2=2t1. Magnetic flux also shifts the flat band’s position in all cases. Additionally, increasing the OSCRI (from 0.5 eV to 1.5 eV) leads to energy level splitting, breaking the symmetry of degenerate states, and widening the band gap. The quantum capacitance is strongly influenced by these parameters, with the peak intensity decreasing with increasing magnetic flux and shifting toward negative gate potentials. The results highlight the square-octagon lattice tunability in both electronic states and charge storage capabilities, making it a promising candidate for applications in nanoelectronics and energy storage devices where precise control over electronic properties is essential.
{"title":"Exploring the Electronic Properties and Quantum Capacitance of the Square-Octagon Lattice for Advanced Electronic and Energy Storage Applications","authors":"Erfan Norian, Mona Abdi, Bandar Astinchap","doi":"10.1039/d5cp00722d","DOIUrl":"https://doi.org/10.1039/d5cp00722d","url":null,"abstract":"This study investigates the square-octagon lattice electronic properties and quantum capacitance under various external parameters, including hopping amplitudes, magnetic flux, and on-site Coulomb repulsion (OSCRI) by using the Hubbard model (HM) and Green function. The analysis reveals that the lattice can exhibit tunable electronic behaviors, transitioning between semiconducting, metallic, and insulating states by adjusting the hopping parameter ratio t2/t1. Specifically, for t2=t1 and t2=3t1, the material remains semiconducting, while for t2=2t1, it behaves as a metal. The application of magnetic flux reduces the band gap for t2=t1 and t2=3t1 while increasing it for t2=2t1. Magnetic flux also shifts the flat band’s position in all cases. Additionally, increasing the OSCRI (from 0.5 eV to 1.5 eV) leads to energy level splitting, breaking the symmetry of degenerate states, and widening the band gap. The quantum capacitance is strongly influenced by these parameters, with the peak intensity decreasing with increasing magnetic flux and shifting toward negative gate potentials. The results highlight the square-octagon lattice tunability in both electronic states and charge storage capabilities, making it a promising candidate for applications in nanoelectronics and energy storage devices where precise control over electronic properties is essential.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"51 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thokozile A. Kathyola, Sin-Yuen Chang, Elizabeth A. Willneff, Colin J. Willis, Giannantonio Cibin, Paul Wilson, Anna B. Kroner, Elizabeth J. Shotton, Peter J. Dowding, Sven L. M. Schroeder
Time-resolved structural changes taking place during the reaction of Ca(OH)2 and CO2 forming different CaCO3 polymorphs, in aqueous and non-aqueous environments, were recorded operando using mid-infrared (mid-IR) and X-ray absorption near-edge structure (XANES) spectroscopy. Results show that Ca(OH)2 directly transforms into calcite in a pure water dispersion. In methanolic media with low water content, calcium di-methylcarbonate (Ca(OCOOCH3)2) is formed, which is hydrolysed to amorphous calcium carbonate (ACC) and vaterite in the presence of sufficient water. The addition of toluene shifts the equilibrium composition further from Ca(OH)2 to ACC and the crystalline forms of CaCO3, probably by affecting the activity of the methoxide intermediate. It can facilitate the formation of aragonite. No Ca(OH)2 conversion was detected in pure ethanol, isopropanol and toluene dispersions, except for nanoscale Ca(OH)2 in ethanolic dispersion, which formed calcium di-ethylcarbonate (Ca(OCOOCH2CH3)2). Our findings underline that vaterite formation is driven by the solution and solid state chemistry related to the reaction via alkoxides and carbonic acid esters of the alcohols, rather than the nucleation process in solution. The alcohol in these systems does not just act as a solvent but as a reactant.
{"title":"How non-aqueous media direct the reaction of Ca(OH)2 with CO2 to different forms of CaCO3: operando mid-infrared and X-ray absorption spectroscopy studies","authors":"Thokozile A. Kathyola, Sin-Yuen Chang, Elizabeth A. Willneff, Colin J. Willis, Giannantonio Cibin, Paul Wilson, Anna B. Kroner, Elizabeth J. Shotton, Peter J. Dowding, Sven L. M. Schroeder","doi":"10.1039/d4cp04774e","DOIUrl":"https://doi.org/10.1039/d4cp04774e","url":null,"abstract":"Time-resolved structural changes taking place during the reaction of Ca(OH)<small><sub>2</sub></small> and CO<small><sub>2</sub></small> forming different CaCO<small><sub>3</sub></small> polymorphs, in aqueous and non-aqueous environments, were recorded <em>operando</em> using mid-infrared (mid-IR) and X-ray absorption near-edge structure (XANES) spectroscopy. Results show that Ca(OH)<small><sub>2</sub></small> directly transforms into calcite in a pure water dispersion. In methanolic media with low water content, calcium di-methylcarbonate (Ca(OCOOCH<small><sub>3</sub></small>)<small><sub>2</sub></small>) is formed, which is hydrolysed to amorphous calcium carbonate (ACC) and vaterite in the presence of sufficient water. The addition of toluene shifts the equilibrium composition further from Ca(OH)<small><sub>2</sub></small> to ACC and the crystalline forms of CaCO<small><sub>3</sub></small>, probably by affecting the activity of the methoxide intermediate. It can facilitate the formation of aragonite. No Ca(OH)<small><sub>2</sub></small> conversion was detected in pure ethanol, isopropanol and toluene dispersions, except for nanoscale Ca(OH)<small><sub>2</sub></small> in ethanolic dispersion, which formed calcium di-ethylcarbonate (Ca(OCOOCH<small><sub>2</sub></small>CH<small><sub>3</sub></small>)<small><sub>2</sub></small>). Our findings underline that vaterite formation is driven by the solution and solid state chemistry related to the reaction <em>via</em> alkoxides and carbonic acid esters of the alcohols, rather than the nucleation process in solution. The alcohol in these systems does not just act as a solvent but as a reactant.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"68 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Cdc2-cyclin B/Wee1 kinase system exhibits bistability between alternative steady states, which emerges due to the mutual inhibition between Cdc2-cyclin B and Wee1 kinases. Alternative steady states are {em M phase-like} state and {em G2 arrest} state, which have implications in the cell cycle progression at the G2 phase in eukaryotic cells. A slight alteration in the feedback strength can drive sudden transitions between these contrasting alternative states upon crossing a critical threshold or a tipping point. The phenomenon of {em critical slowing down} (CSD) has been widely used to identify the proximity to a tipping point. However, determining the key variable or species that best signals CSD is a challenging task and holds significance in complex biochemical processes. Here, we determine the key variable or observation direction (OD) from the direction of CSD to best detect an upcoming transition in the Cdc2-cyclin B/Wee1 model system. We find that with increasing feedback strength, the Cdc2-cyclin B is the OD, as it produces a stronger signal than that of Wee1. With decreasing feedback strength, both Cdc2-cyclin B and Wee1 produce similar signals and can be used as OD. Further, the noise-sensitive direction highlights the effect of stochasticity in Cdc2-cyclin B and Wee1 for increasing and decreasing feedback strength, respectively. We also perform sensitivity analyses that reveal the robustness of the OD. Finally, we compare the efficacy of OD with principal component analysis while detecting a tipping point, and also validate its general applicability to epithelial-mesenchymal transition for cancer progression.
{"title":"A general, robust framework for determining the key species that forewarns sudden transitions in biological circuits","authors":"Dinesh Kashyap, Taranjot Kaur, Parthasharathi Dutta, Sudipta Sinha","doi":"10.1039/d4cp04863f","DOIUrl":"https://doi.org/10.1039/d4cp04863f","url":null,"abstract":"The Cdc2-cyclin B/Wee1 kinase system exhibits bistability between alternative steady states, which emerges due to the mutual inhibition between Cdc2-cyclin B and Wee1 kinases. Alternative steady states are {em M phase-like} state and {em G2 arrest} state, which have implications in the cell cycle progression at the G2 phase in eukaryotic cells. A slight alteration in the feedback strength can drive sudden transitions between these contrasting alternative states upon crossing a critical threshold or a tipping point. The phenomenon of {em critical slowing down} (CSD) has been widely used to identify the proximity to a tipping point. However, determining the key variable or species that best signals CSD is a challenging task and holds significance in complex biochemical processes. Here, we determine the key variable or observation direction (OD) from the direction of CSD to best detect an upcoming transition in the Cdc2-cyclin B/Wee1 model system. We find that with increasing feedback strength, the Cdc2-cyclin B is the OD, as it produces a stronger signal than that of Wee1. With decreasing feedback strength, both Cdc2-cyclin B and Wee1 produce similar signals and can be used as OD. Further, the noise-sensitive direction highlights the effect of stochasticity in Cdc2-cyclin B and Wee1 for increasing and decreasing feedback strength, respectively. We also perform sensitivity analyses that reveal the robustness of the OD. Finally, we compare the efficacy of OD with principal component analysis while detecting a tipping point, and also validate its general applicability to epithelial-mesenchymal transition for cancer progression.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"47 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The development of cost-effective and highly efficient multifunctional catalysts for water splitting and hydrogen fuel cells is crucial for advancing renewable energy technologies. This study employs density functional theory to investigate the electrocatalytic performance of Janus-type WSSe (JW) transition metal dichalcogenides toward the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). Additionally, the impact of nonmetal doping (NM = C, O, N, P) at the S and Se sites in the JW structure is explored. The cohesive energy of -5.82 eV/atom and minimal fluctuations in AIMD simulations over 10 ps at 300 K and 500 K confirm structural stability. Although the pristine structure exhibits a high overpotential, NM doping substantially improves catalytic performance, making it more suitable for efficient energy conversion applications. The N doped JW system demonstrates exceptional multifunctional performance, with NS@JW showing overpotentials of 0.34 V (HER), 0.18 V (OER), and 0.14 V (ORR), while NSe@JW exhibits 0.35 V (HER), 0.46 V (OER), and 0.24 V (ORR). This outstanding performance results from bonding-antibonding interactions in intermediate adsorption, as confirmed by crystal orbital Hamiltonian population analysis. This comprehensive study highlights the promise of Janus-type WSSe and emphasizes the crucial role of NM doping in boosting catalytic efficiency, offering key insights for designing cost-effective, high-performance multifunctional electrocatalysts for energy conversion.
{"title":"Delineating the Multifunctional Performance of Janus WSSe with Nonmetals in Water Splitting and Hydrogen Fuel Cell Applications via First-Principles Calculations","authors":"Deepak Arumugam, Divyakaaviri Subramani, Shamini Pazhani Beena, Shankar Ramasamy","doi":"10.1039/d5cp00952a","DOIUrl":"https://doi.org/10.1039/d5cp00952a","url":null,"abstract":"The development of cost-effective and highly efficient multifunctional catalysts for water splitting and hydrogen fuel cells is crucial for advancing renewable energy technologies. This study employs density functional theory to investigate the electrocatalytic performance of Janus-type WSSe (JW) transition metal dichalcogenides toward the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). Additionally, the impact of nonmetal doping (NM = C, O, N, P) at the S and Se sites in the JW structure is explored. The cohesive energy of -5.82 eV/atom and minimal fluctuations in AIMD simulations over 10 ps at 300 K and 500 K confirm structural stability. Although the pristine structure exhibits a high overpotential, NM doping substantially improves catalytic performance, making it more suitable for efficient energy conversion applications. The N doped JW system demonstrates exceptional multifunctional performance, with NS@JW showing overpotentials of 0.34 V (HER), 0.18 V (OER), and 0.14 V (ORR), while NSe@JW exhibits 0.35 V (HER), 0.46 V (OER), and 0.24 V (ORR). This outstanding performance results from bonding-antibonding interactions in intermediate adsorption, as confirmed by crystal orbital Hamiltonian population analysis. This comprehensive study highlights the promise of Janus-type WSSe and emphasizes the crucial role of NM doping in boosting catalytic efficiency, offering key insights for designing cost-effective, high-performance multifunctional electrocatalysts for energy conversion.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"18 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Niklas von Rhein, Jian Liang Low, Charlotte Gallenkamp, Beate Paulus, Vera Krewald
A promising alternative for platinum-based electrocatalysts for the Oxygen Reduction Reaction are single-atom catalysts, particularly those based on iron, nitrogen and carbon. The active sites in FeNC catalysts are conceived of as individual FeN4 centres embedded in a carbon matrix, often approximated by a planar sheet. While the coordination of FeN4 centres via pyridinic nitrogen atoms, i.e. six-membered rings, does not break the symmetry of the graphene plane, coordination via pyrrolic, i.e. five membered rings, induces defects in the carbon matrix that can lift its planarity. Deviation from planarity is expected to influence the electronic properties of the FeN4 centres. An open question is whether spectroscopic techniques can detect such differences. Among these, Mössbauer spectroscopy is of central importance to characterising FeNC catalyst materials. Since pyrrolic models have recently emerged as a spectroscopically and thermodynamically consistent model for FeNC active sites, we herein compare three different pyrrolic FeN4 models proposed in the literature and discuss whether and how these pyrrolic centres can be discerned spectroscopically.
{"title":"Pyrrolic FeN4 models for FeNC catalysts: the influence of planarity on electronic properties and Mössbauer parameters","authors":"Niklas von Rhein, Jian Liang Low, Charlotte Gallenkamp, Beate Paulus, Vera Krewald","doi":"10.1039/d5cp00443h","DOIUrl":"https://doi.org/10.1039/d5cp00443h","url":null,"abstract":"A promising alternative for platinum-based electrocatalysts for the Oxygen Reduction Reaction are single-atom catalysts, particularly those based on iron, nitrogen and carbon. The active sites in FeNC catalysts are conceived of as individual FeN<small><sub>4</sub></small> centres embedded in a carbon matrix, often approximated by a planar sheet. While the coordination of FeN<small><sub>4</sub></small> centres via pyridinic nitrogen atoms, i.e. six-membered rings, does not break the symmetry of the graphene plane, coordination via pyrrolic, i.e. five membered rings, induces defects in the carbon matrix that can lift its planarity. Deviation from planarity is expected to influence the electronic properties of the FeN<small><sub>4</sub></small> centres. An open question is whether spectroscopic techniques can detect such differences. Among these, Mössbauer spectroscopy is of central importance to characterising FeNC catalyst materials. Since pyrrolic models have recently emerged as a spectroscopically and thermodynamically consistent model for FeNC active sites, we herein compare three different pyrrolic FeN<small><sub>4</sub></small> models proposed in the literature and discuss whether and how these pyrrolic centres can be discerned spectroscopically.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"16 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Melinda Nolten, Kay T. Xia, Simone Pezzotti, Gerhard Schwaab, Robert G Bergman, Kenneth Raymond, F. Dean Toste, Teresa Head-Gordon, Wan-Lu Li, Martina Havenith
Supramolecular hosts create unique microenvironments which enable the tuning of reactions via steric confinement and electrostatics. It has been shown that “solvent shaping inside hydrophobic cavities” is an important thermodynamic driving force for guest encapsulation in the nanocage host. Here, we show that even small (5%) changes in the solvent composition can have a profound impact on the free energy of encapsulation. In a combined THz, NMR and ab initio MD study, we reveal that the preferential residing of a single DMSO molecule in the cavity upon addition of ≥5% DMSO results in a considerable change of ΔS from 63-76 cal⋅mol–1⋅K–1 to 23-24 cal⋅mol–1⋅K–1. This can be rationalized by reduction of the cavity volume due to the DMSO molecule which resides preferentially in the cavity. These results provide novel insights into the guest-binding interactions, emphasizing that the entropic driving force is notably influenced by even small changes in the solvent composition. The impact of embedding a single DMSO molecules exceeds the alternative choice of the metal ligand by far. We demonstrate that the local solvent composition within the cage is essential for regulating catalytic efficiency, thus solvent tuning might enable novel applications in supramolecular chemistry in catalysis and chemical separation.
{"title":"Tuning the Free Energy of Host-Guest Encapsulation by Cosolvent","authors":"Melinda Nolten, Kay T. Xia, Simone Pezzotti, Gerhard Schwaab, Robert G Bergman, Kenneth Raymond, F. Dean Toste, Teresa Head-Gordon, Wan-Lu Li, Martina Havenith","doi":"10.1039/d5cp00661a","DOIUrl":"https://doi.org/10.1039/d5cp00661a","url":null,"abstract":"Supramolecular hosts create unique microenvironments which enable the tuning of reactions via steric confinement and electrostatics. It has been shown that “solvent shaping inside hydrophobic cavities” is an important thermodynamic driving force for guest encapsulation in the nanocage host. Here, we show that even small (5%) changes in the solvent composition can have a profound impact on the free energy of encapsulation. In a combined THz, NMR and ab initio MD study, we reveal that the preferential residing of a single DMSO molecule in the cavity upon addition of ≥5% DMSO results in a considerable change of ΔS from 63-76 cal⋅mol–1⋅K–1 to 23-24 cal⋅mol–1⋅K–1. This can be rationalized by reduction of the cavity volume due to the DMSO molecule which resides preferentially in the cavity. These results provide novel insights into the guest-binding interactions, emphasizing that the entropic driving force is notably influenced by even small changes in the solvent composition. The impact of embedding a single DMSO molecules exceeds the alternative choice of the metal ligand by far. We demonstrate that the local solvent composition within the cage is essential for regulating catalytic efficiency, thus solvent tuning might enable novel applications in supramolecular chemistry in catalysis and chemical separation.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"47 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chu Qing, Bo Peng, Lei Yuan, Yuming Zhang, Renxu Jia, Lian Bi Li
Van der Waals heterostructures have attracted widespread attention due to their unique photoelectric properties. In this study, the MoTe2/BP vdWH's formation and stability, electrical structure, and optical properties are examined utilizing density functional theory (DFT) calculations. Using the PBE and HSE06 methods, it is discovered that the type of band alignment in the heterojunction is type-I, and it has indirect bandgap of 1.01 eV and 1.44 eV, respectively. A weak van der Waals force exists between the MoTe2 and BP layers. Notably, compared to isolated MoTe2 and BP monolayers, the heterojunction demonstrates a higher absorption coefficient (~105 cm-1) and a broader absorption wavelength range. Furthermore, we have shown that the type of band alignments of the heterojunction can be adjusted by applying biaxial strain, introducing an external electric field, and altering the interlayer spacing. These adjustments enable type-I to type-II band alignment and semiconductor-metal transitions. With the interlayer spacing increasing and tensile stress applied, the absorption intensity in the UV-Vis range gradually decreases. Interestingly, the external electric field shows minimal impact on the absorption intensity. This study offers insightful theoretical direction for prospective uses of novel 2D van der Waals heterostructures in various fields, including solar cells and photodetectors.
{"title":"Tunable electronic and optical properties of MoTe2/black phosphorene van der Waals heterostructure: a first-principles study","authors":"Chu Qing, Bo Peng, Lei Yuan, Yuming Zhang, Renxu Jia, Lian Bi Li","doi":"10.1039/d5cp00675a","DOIUrl":"https://doi.org/10.1039/d5cp00675a","url":null,"abstract":"Van der Waals heterostructures have attracted widespread attention due to their unique photoelectric properties. In this study, the MoTe2/BP vdWH's formation and stability, electrical structure, and optical properties are examined utilizing density functional theory (DFT) calculations. Using the PBE and HSE06 methods, it is discovered that the type of band alignment in the heterojunction is type-I, and it has indirect bandgap of 1.01 eV and 1.44 eV, respectively. A weak van der Waals force exists between the MoTe2 and BP layers. Notably, compared to isolated MoTe2 and BP monolayers, the heterojunction demonstrates a higher absorption coefficient (~105 cm-1) and a broader absorption wavelength range. Furthermore, we have shown that the type of band alignments of the heterojunction can be adjusted by applying biaxial strain, introducing an external electric field, and altering the interlayer spacing. These adjustments enable type-I to type-II band alignment and semiconductor-metal transitions. With the interlayer spacing increasing and tensile stress applied, the absorption intensity in the UV-Vis range gradually decreases. Interestingly, the external electric field shows minimal impact on the absorption intensity. This study offers insightful theoretical direction for prospective uses of novel 2D van der Waals heterostructures in various fields, including solar cells and photodetectors.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"43 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigates the influence of rutile-phase TiO2 nanoparticles on the structural, morphological, and vibrational properties of polystyrene (PS)-based nanocomposites at 3%, 5%, and 10%TiO2 concentrations. Nanocomposites were fabricated via solution mixing and hot pressing. TEM revealed well-dispersed nanoparticles (30–50 nm) in 3% TiO2 samples, with agglomeration increasing at 5%TiO2. AFM showed a rougher surface for 3% TiO2 (90–160 nm) and smoother, more uniform surfaces for 10%TiO2 (50–130 nm), attributed to improved dispersion. XRD indicated enhanced crystallinity with higher TiO2 content, with crystallite sizes between 5.77 nm and 8.05 nm. Williamson–Hall and Halder–Wagner analyses highlighted strain effects at lower concentrations. Raman spectroscopy identified TiO2 peaks (447 cm−1, 618 cm−1, 905 cm−1) intensifying with TiO2 content, while PS peak shifts suggested matrix-nanoparticle interactions. These results underscore the critical role of TiO2 dispersion and loading in determining PS nanocomposite properties.
{"title":"Effect of nanoparticle concentration on the crystallinity, vibrational dynamics and morphology of PS/TiO2 nanocomposites: a comprehensive study","authors":"A. Rahimli, M. Jafarov","doi":"10.1039/d5cp00521c","DOIUrl":"https://doi.org/10.1039/d5cp00521c","url":null,"abstract":"This study investigates the influence of rutile-phase TiO<small><sub>2</sub></small> nanoparticles on the structural, morphological, and vibrational properties of polystyrene (PS)-based nanocomposites at 3%, 5%, and 10%TiO<small><sub>2</sub></small> concentrations. Nanocomposites were fabricated <em>via</em> solution mixing and hot pressing. TEM revealed well-dispersed nanoparticles (30–50 nm) in 3% TiO<small><sub>2</sub></small> samples, with agglomeration increasing at 5%TiO<small><sub>2</sub></small>. AFM showed a rougher surface for 3% TiO<small><sub>2</sub></small> (90–160 nm) and smoother, more uniform surfaces for 10%TiO<small><sub>2</sub></small> (50–130 nm), attributed to improved dispersion. XRD indicated enhanced crystallinity with higher TiO<small><sub>2</sub></small> content, with crystallite sizes between 5.77 nm and 8.05 nm. Williamson–Hall and Halder–Wagner analyses highlighted strain effects at lower concentrations. Raman spectroscopy identified TiO<small><sub>2</sub></small> peaks (447 cm<small><sup>−1</sup></small>, 618 cm<small><sup>−1</sup></small>, 905 cm<small><sup>−1</sup></small>) intensifying with TiO<small><sub>2</sub></small> content, while PS peak shifts suggested matrix-nanoparticle interactions. These results underscore the critical role of TiO<small><sub>2</sub></small> dispersion and loading in determining PS nanocomposite properties.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"63 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The electrostatic forces supported by hydrogen-bonding (H-bonding) interactions in the presence of surfactants stabilizes the microemulsions in general. It would be quite surprising to have surfactant free microemulsions (SFMEs) predominantly stabilized by weak but large number of H-bonding interactions contrary to common wisdom. Herein, the formulation and characterization of SFMEs comprising a hydrophobic ionic liquid (IL) and a deep eutectic solvent (DES) exhibiting high thermal stability is reported. The constituents of DES namely ethylene glycol (EG) and choline chloride (ChCl) act as polar and amphiphile components, respectively and an IL, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide works as a hydrophobic entity to form SFME. The formation mechanism as well as high temperature thermal stability of SFMEs has been discussed in terms of relative changes in the thickness of interfacial film stabilizing the polar and non-polar pseudo-domains predominantly via alteration in H-bonding interactions, which is supported by computational studies. The sufficiently low interfacial energy in SFMEs has been exploited to thermally stabilize Lysozyme (LYZ) in SFMEs, which showed remarkable thermal stability (up to 150 oC) as revealed by comparative enzyme activity at room temperature after heating, which is quite higher than that observed in buffer. The present study not only adds to the existing knowledge about the formation and stability of SFMEs but is also expected to prompt other researchers for designing relatively greener IL or deep eutectic solvent (DES) based SFMEs for utilization in various biological and other applications.
{"title":"Surfactant Free Microemulsions as Fluid Scaffolds for Thermal Stabilization of Lysozyme","authors":"Manvir Kaur, Manpreet Singh, Rajwinder Kaur, Navdeep Kaur, Pratap Kumar Pati, Tejwant Singh Kang","doi":"10.1039/d5cp00678c","DOIUrl":"https://doi.org/10.1039/d5cp00678c","url":null,"abstract":"The electrostatic forces supported by hydrogen-bonding (H-bonding) interactions in the presence of surfactants stabilizes the microemulsions in general. It would be quite surprising to have surfactant free microemulsions (SFMEs) predominantly stabilized by weak but large number of H-bonding interactions contrary to common wisdom. Herein, the formulation and characterization of SFMEs comprising a hydrophobic ionic liquid (IL) and a deep eutectic solvent (DES) exhibiting high thermal stability is reported. The constituents of DES namely ethylene glycol (EG) and choline chloride (ChCl) act as polar and amphiphile components, respectively and an IL, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide works as a hydrophobic entity to form SFME. The formation mechanism as well as high temperature thermal stability of SFMEs has been discussed in terms of relative changes in the thickness of interfacial film stabilizing the polar and non-polar pseudo-domains predominantly via alteration in H-bonding interactions, which is supported by computational studies. The sufficiently low interfacial energy in SFMEs has been exploited to thermally stabilize Lysozyme (LYZ) in SFMEs, which showed remarkable thermal stability (up to 150 oC) as revealed by comparative enzyme activity at room temperature after heating, which is quite higher than that observed in buffer. The present study not only adds to the existing knowledge about the formation and stability of SFMEs but is also expected to prompt other researchers for designing relatively greener IL or deep eutectic solvent (DES) based SFMEs for utilization in various biological and other applications.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"37 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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