Chemphyschem最新文献_第10页

Structural Elucidation of Photoluminescent Carbon Nanodots through Quenching Kinetics with Molecular Electron Donors and Acceptors

IF 2.3 3区化学

Chemphyschem Pub Date : 2025-01-29 DOI: 10.1002/cphc.202400952

Almaz S. Jalilov, Wan Ryan Asri, Asem Alenaizan

引用次数: 0

Competition Between Halogen Atom and Ring of Halobenzenes as Hydrogen Bond Electron Donor Sites

IF 2.3 3区化学

Chemphyschem Pub Date : 2025-01-27 DOI: 10.1002/cphc.202401043

Dr. Akhtam Amonov, Prof. Steve Scheiner

引用次数: 0

Iron-Histidine Coordination in Cytochrome b5: A Local Vibrational Mode Study

IF 2.3 3区化学

Chemphyschem Pub Date : 2025-01-27 DOI: 10.1002/cphc.202401098

Prof. Dr. Marek Freindorf, Kevin Fleming, Prof. Dr. Elfi Kraka

{"title":"Iron-Histidine Coordination in Cytochrome b5: A Local Vibrational Mode Study","authors":"Prof. Dr. Marek Freindorf, Kevin Fleming, Prof. Dr. Elfi Kraka","doi":"10.1002/cphc.202401098","DOIUrl":"10.1002/cphc.202401098","url":null,"abstract":"For a series of cytochrome b5 proteins isolated from various species, including bacteria, animals, and humans, we analyzed the intrinsic strength of their distal/proximal FeN bonds and the intrinsic stiffness of their axial NFeN bond angles. To assess intrinsic bond strength and bond angle stiffness, we employed local vibrational stretching force constants ka(FeN) and bending force constants ka(NFeN) derived from the local mode theory developed by our group; the ferric and ferrous oxidation states of the heme Fe were considered. All calculations were conducted with the QM/MM methodology. We found that the reduction of the heme Fe from the ferric to the ferrous state makes the FeN axial bonds weaker, longer, less covalent, and less polar. Additionally, the axial NFeN bond angle becomes stiffer and less flexible. Local mode force constants turned out to be far more sensitive to the protein environment than geometries; evaluating force constant trends across diverse protein groups and monitoring changes in the axial heme-framework revealed redox-induced changes to the primary coordination sphere of the protein. These results indicate that local mode force constants can serve as useful feature data for training machine learning models that predict cytochrome b5 redox potentials, which currently rely more on geometric data and qualitative descriptors of the protein environment. The insights gained through our investigation also offer valuable guidance for strategically fine-tuning artificial cytochrome b5 proteins and designing new, versatile variants.","PeriodicalId":9819,"journal":{"name":"Chemphyschem","volume":"26 7","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143051760","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}

引用次数: 0

Exploring Surface State and Exciplex Dominated Aggregation Induced Electrochemiluminescence of Graphene Quantum Dots Prepared via Electrochemical Exfoliation

IF 2.3 3区化学

Chemphyschem Pub Date : 2025-01-27 DOI: 10.1002/cphc.202401074

Congyang Zhang, Zhenzhong Cai, Kenneth Chu, Wai-Tung Shiu, Ping Hu, Lijia Liu, Qiao Zhang, Zhifeng Ding

{"title":"Exploring Surface State and Exciplex Dominated Aggregation Induced Electrochemiluminescence of Graphene Quantum Dots Prepared via Electrochemical Exfoliation","authors":"Congyang Zhang, Zhenzhong Cai, Kenneth Chu, Wai-Tung Shiu, Ping Hu, Lijia Liu, Qiao Zhang, Zhifeng Ding","doi":"10.1002/cphc.202401074","DOIUrl":"10.1002/cphc.202401074","url":null,"abstract":"Graphene quantum dots (GQDs) have emerged as promising materials for electrochemiluminescence (ECL) applications due to their unique optical and electronic properties. In this study, GQDs were synthesized via electrochemical exfoliation of graphite in a constant current density mode, enabling scalable production with controlled size and surface functionalization. GQDs-4 and GQDs-20, synthesized at applied current densities of 4 mA/cm2 and 20 mA/cm2 to the graphite electrode, respectively, were investigated on roles of surface states and exciplex dominated aggregation-induced emission (AIE) in their ECL performance. GQDs-4 obtained an absolute ECL quantum efficiency of 0.0012 %±0.0002 %. GQDs-20, with a smaller particle size, achieved an absolute ECL quantum efficiency of 0.028±0.002 %, demonstrating high efficiency in converting electrons into photons. While GQDs-4 exhibited minor intensity in PL and ECL, they displayed a similar emission spectrum to GQDs-20 in the ECL process. This finding highlights the significant role of surface states and AIE in influencing the emission properties of GQDs, independent from core-state transitions. These results provide critical insights into the mechanisms governing GQD-based ECL and offer pathways for optimizing these materials for use in biosensing, optoelectronics, and imaging applications. Keywords: Electrochemiluminescence, Graphene Quantum Dots, Exciplex, Surface States, Multi-color Emission.","PeriodicalId":9819,"journal":{"name":"Chemphyschem","volume":"26 7","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cphc.202401074","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143045643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Understanding the Effects of Edge Planes in Porous Carbon: Quantum Capacitance and Electrolyte Behavior in Supercapacitor

IF 2.3 3区化学

Chemphyschem Pub Date : 2025-01-26 DOI: 10.1002/cphc.202401006

Guipei Xu, Zonglin Yi, Hao Liu, Jiewen Lai, Huifang Di, Yifeng Lu, Hui Huang, Zhenbing Wang

{"title":"Understanding the Effects of Edge Planes in Porous Carbon: Quantum Capacitance and Electrolyte Behavior in Supercapacitor","authors":"Guipei Xu, Zonglin Yi, Hao Liu, Jiewen Lai, Huifang Di, Yifeng Lu, Hui Huang, Zhenbing Wang","doi":"10.1002/cphc.202401006","DOIUrl":"10.1002/cphc.202401006","url":null,"abstract":"Electric double layer capacitors (EDLC) require large specific surface area to provide high power density. The generation of pores increases the electrochemical capacitance with more graphitic edge planes exposed to the electrolyte. Conventional theory believes this increasing in capacitance is owed to the increased specific surface area, but our work uncovers another mechanism. DFT calculations discover the commonly seen defect-free zigzag and armchair edges can increase the quantum capacitance (CQ) due to their high chemical activity. Meanwhile, high chemical activity makes defect-free edges interact with electrolyte molecules more easily, leading to the potential reduce of electrolyte stabilization and the change on the origin mechanism of double layer capacitance (CD). Additionally, edges with non-hexagonal defects show a better balance between high CQ and electrolyte stability. Therefore, our discovery proves the preservation of non-hexagonal defects in edge planes through possible temperature controlling in heat treatment is important in reaching high electrochemical properties for EDLC.","PeriodicalId":9819,"journal":{"name":"Chemphyschem","volume":"26 7","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143045647","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}

引用次数: 0

Spectral Narrowing Strategies in Multiple Resonance Thermally Activated Delayed Fluorescence Materials

IF 2.3 3区化学

Chemphyschem Pub Date : 2025-01-25 DOI: 10.1002/cphc.202400955

Qianyu He, Mengke Li, Shi-Jian Su

引用次数: 0

Planar Pentacoordinate Bromine in Global Minimum Br6Li5.

IF 2.3 3区化学

Chemphyschem Pub Date : 2025-01-24 DOI: 10.1002/cphc.202400882

Rui Sun, Bo Jin, Jinzhong Zhao, Xin Wu, Caixia Yuan

引用次数: 0

α/β Conflicting Aromaticity Under the Microscope: Study of Pro-Aromatic Radicals

IF 2.3 3区化学

Chemphyschem Pub Date : 2025-01-24 DOI: 10.1002/cphc.202400529

Raúl Lago-Saavedra, Ignacio Pérez-Juste, Marcos Mandado

{"title":"α/β Conflicting Aromaticity Under the Microscope: Study of Pro-Aromatic Radicals","authors":"Raúl Lago-Saavedra, Ignacio Pérez-Juste, Marcos Mandado","doi":"10.1002/cphc.202400529","DOIUrl":"10.1002/cphc.202400529","url":null,"abstract":"The aromaticity of a representative sample of pro-aromatic radicals and its nitro, amino, hydroxyl and imine substituted derivatives has been analysed by means of multicenter delocalization indices (MCI) and nuclear-independent chemical shifts (NICS). Because of their radical character, these compounds may exhibit conflicting α/β aromaticity, so that the contribution of α and β electrons to the MCI and NICS has been analysed separately and their values qualitatively interpreted in terms of the 2n+1/2n rule. All the monocyclic radicals investigated show conflicting α/β aromaticity. Thus, significant MCI values have been found for one of the spin components, whereas negligible values, even slightly negative, have been obtained for the other spin component. NICS indices confirm the aromatic character reflected by the MCIs and clearly show the antiaromatic or non-aromatic character of the other spin components. The same has been found for the donor rings of the bicyclic pro-aromatic radicals investigated, whereas all the fused benzene rings of these radicals show a clear aromatic character in both spin components. Substitutions at the donor carbon position by strong deactivating groups provoke a small increase of the aromatic character in the aromatic spin components and a significant decrease of the antiaromatic character in the antiaromatic spin components whereas activating groups have little effect.","PeriodicalId":9819,"journal":{"name":"Chemphyschem","volume":"26 7","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143032385","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}

引用次数: 0

RF Heating Effects in CEST NMR with Hyperpolarized ¹²⁹Xe Considering Different Spin Exchange Kinetics and Saturation Schemes. 考虑不同自旋交换动力学和饱和方案的超极化129Xe CEST核磁共振射频加热效应。

IF 2.3 3区化学

Chemphyschem Pub Date : 2025-01-22 DOI: 10.1002/cphc.202401037

David Hernandez-Solarte, Leif Schröder

{"title":"RF Heating Effects in CEST NMR with Hyperpolarized 129Xe Considering Different Spin Exchange Kinetics and Saturation Schemes.","authors":"David Hernandez-Solarte, Leif Schröder","doi":"10.1002/cphc.202401037","DOIUrl":"10.1002/cphc.202401037","url":null,"abstract":"Chemical exchange saturation transfer (CEST) improves the sensitivity of NMR but depending on the spin exchange kinetics, it can require substantial RF energy deposition to label magnetization. Potential side effects like RF-induced heating may occur and must be monitored. Here, we explore the parameter space considering not only undesired heating but also efficient CEST build-up (depolarization rate), spectral resolution (line width), and subsequent effects like changes in chemical shifts of CEST responses. We present a systematic study to compare conventional block pulse with shaped-pulse saturation and quantify how the effective average saturation power impacts these parameters. Pulse shape and nominal excitation bandwidth, however, turned out to have little impact on acquired z-spectra and temperature changes. This study illustrates how different exchange kinetics define different regimes of suitable RF power within the dynamic range of fully saturable magnetization from hyperpolarized 129Xe. Temperature-related changes in the resonance frequency of bound spins were also quantified for the two Xe hosts CB6 and CrA-ma and put into context for typically used CEST acquisition parameters, including the stability of the magnetic field.","PeriodicalId":9819,"journal":{"name":"Chemphyschem","volume":" ","pages":"e202401037"},"PeriodicalIF":2.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143000967","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}

引用次数: 0

Dynamics of Pyrene Excimer in a Cholesteryl-Based Supramolecular Host Matrix 芘准分子在胆固醇基超分子宿主基质中的动力学。

IF 2.3 3区化学

Chemphyschem Pub Date : 2025-01-22 DOI: 10.1002/cphc.202400969

Shubham Verma, Gargee Roy, Nikumoni Doley, Deepak Asthana, Sachin Dev Verma

{"title":"Dynamics of Pyrene Excimer in a Cholesteryl-Based Supramolecular Host Matrix","authors":"Shubham Verma, Gargee Roy, Nikumoni Doley, Deepak Asthana, Sachin Dev Verma","doi":"10.1002/cphc.202400969","DOIUrl":"10.1002/cphc.202400969","url":null,"abstract":"Aggregation-caused quenching (ACQ) reduces luminescence and compromises brightness in solid-state displays, necessitating strategies to mitigate its effects for enhanced performance. This study presents cost-effective method to mitigate ACQ of pyrene by co-assembling polycyclic aromatic hydrocarbons within low molecular weight gelator. Synthesized from readily available materials – cholesteryl chloroformate and pentaerythritol – in one-step reaction, gelator incorporates four cholesteryl units, reported to promote robust supramolecular gels in various solvents. Encapsulation of pyrene in a supramolecular host has effectively addressed the challenge of ACQ in the solid-state. Utilizing steady-state and time-resolved spectroscopic techniques, we probed the excimer formation dynamics across solution, powder, and xerogel phases. Through time-resolved emission spectra (TRES) and time-resolved area-normalized emission spectra (TRANES), we observed the monomer-to-excimer transition under various conditions. In solution, this transition occurs in a single step, characterized by a single isoemissive point (~443 nm) observed in TRANES. In powder, two isoemissive points (~445 nm and ~485 nm) were observed, indicating more complex process with an additional relaxed or trap state. The xerogel phase revealed an intricate excimer formation pathway, involving three isoemissive points (~418 nm, ~442 nm, and ~423 nm). These observations suggest multiple intermediate states in monomer-excimer transition and distinct dynamics in the solid matrix.","PeriodicalId":9819,"journal":{"name":"Chemphyschem","volume":"26 7","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143000932","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}

引用次数: 0