Accurate milk composition analysis is crucial for improving product quality, economic efficiency, and animal health in the dairy industry. Near-infrared (NIR) spectroscopy can quantify milk composition quickly and nondestructively. However, external factors, such as temperature fluctuations, can alter the molecular vibrations and hydrogen bonding in milk, altering the NIR spectra and leading to errors in predicting key constituents such as fat, protein, and lactose. This study compares the effectiveness of Piecewise Direct Standardization (PDS), Continuous PDS (CPDS), External Parameter Orthogonalization (EPO), and Dynamic Orthogonal Projection (DOP in correcting the impact of temperature-induced variations on predictions in milk long-wave NIR spectra (LW-NIR, 1000 to 1700 nm). A total of 270 raw milk samples were analyzed, collecting both reflectance and transmittance spectra at five different temperatures (20°C, 25°C, 30°C, 35°C, and 40°C). The experimental setup ensured precise temperature control and accurate spectral measurements. PLSR models were calibrated at 30°C to predict milk fat, protein, and lactose content. The performance of these models was assessed before and after applying the temperature correction methods, with a primary focus on reflectance spectra. Results indicate that EPO and DOP significantly enhance model robustness and prediction accuracy across all temperatures, outperforming PDS and CPDS, especially for lactose prediction. These orthogonalization methods were compared against PLSR models calibrated with spectra from all temperatures. EPO and DOP showed comparable or superior performance, highlighting their effectiveness without requiring extensive temperature-specific calibration data. These findings suggest that orthogonalization methods are particularly suitable for in-line milk quality measurements under farm conditions where temperature control is challenging. This study highlights the potential of advanced chemometric techniques to improve real- time, on-farm milk composition analysis, facilitating better farm management and enhanced dairy product quality.
{"title":"Temperature Correction of Near-Infrared Spectra of Raw Milk","authors":"José Antonio, Díaz Olivares, Stef, Grauwels, Xinyue, Fu, Ines, Adriaens, Wouter, Saeys, Ryad, Bendoula, Jean-Michel, Roger, Ben, Aernouts","doi":"10.26434/chemrxiv-2024-ls0j0","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-ls0j0","url":null,"abstract":"Accurate milk composition analysis is crucial for improving product quality, economic efficiency, and animal health in the dairy industry. Near-infrared (NIR) spectroscopy can quantify milk composition quickly and nondestructively. However, external factors, such as temperature fluctuations, can alter the molecular vibrations and hydrogen bonding in milk, altering the NIR spectra and leading to errors in predicting key constituents such as fat, protein, and lactose. This study compares the effectiveness of Piecewise Direct Standardization (PDS), Continuous PDS (CPDS), External Parameter Orthogonalization (EPO), and Dynamic Orthogonal Projection (DOP in correcting the impact of temperature-induced variations on predictions in milk long-wave NIR spectra (LW-NIR, 1000 to 1700 nm).\u0000A total of 270 raw milk samples were analyzed, collecting both reflectance and transmittance spectra at five different temperatures (20°C, 25°C, 30°C, 35°C, and 40°C). The experimental setup ensured precise temperature control and accurate spectral measurements. PLSR models were calibrated at 30°C to predict milk fat, protein, and lactose content. The performance of these models was assessed before and after applying the temperature correction methods, with a primary focus on reflectance spectra.\u0000Results indicate that EPO and DOP significantly enhance model robustness and prediction accuracy across all temperatures, outperforming PDS and CPDS, especially for lactose prediction. These orthogonalization methods were compared against PLSR models calibrated with spectra from all temperatures. EPO and DOP showed comparable or superior performance, highlighting their effectiveness without requiring extensive temperature-specific calibration data. These findings suggest that orthogonalization methods are particularly suitable for in-line milk quality measurements under farm conditions where temperature control is challenging. This study highlights the potential of advanced chemometric techniques to improve real- time, on-farm milk composition analysis, facilitating better farm management and enhanced dairy product quality.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Several industrial processes are carried out on moving bed reactors (MBRs), and the development of mathematical models plays a fundamental role in designing, optimizing, and controlling these processes. Thus, this work initially develops a local solution for a linearized vertical MBR model to lumped parameters in the solid and fluid phases. Then, a semi-analytical solution (SAS) of the original nonlinear problem is obtained from the local solution. The SAS is easy to implement, stable, accurate, and performs fast, making it an efficient tool for MBR simulations. Excellent agreement was found comparing the SAS results with those of traditional numerical methods. SAS is capable of fast integration of model equations for systems with stiffness ratio SR=10^33. A numerical analysis was also carried out, indicating optimal refining parameters in relation to linearization error and machine error. The developments carried out can be easily extended to systems with multiple first-order reactions.
{"title":"Semi-Analytical Solution for a Lumped Model of a Co-Current Moving Bed Reactor","authors":"Natan, Padoin, Cíntia, Soares, Sávio , Bertoli, Jesús, Apolinar-Hernández, Carolina, Krebs de Souza, Marcel, Jeferson Gonçalves","doi":"10.26434/chemrxiv-2024-t30tv","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-t30tv","url":null,"abstract":"Several industrial processes are carried out on moving bed reactors (MBRs), and the development of mathematical models plays a fundamental role in designing, optimizing, and controlling these processes. Thus, this work initially develops a local solution for a linearized vertical MBR model to lumped parameters in the solid and fluid phases. Then, a semi-analytical solution (SAS) of the original nonlinear problem is obtained from the local solution. The SAS is easy to implement, stable, accurate, and performs fast, making it an efficient tool for MBR simulations. Excellent agreement was found comparing the SAS results with those of traditional numerical methods. SAS is capable of fast integration of model equations for systems with stiffness ratio SR=10^33. A numerical analysis was also carried out, indicating optimal refining parameters in relation to linearization error and machine error. The developments carried out can be easily extended to systems with multiple first-order reactions.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-18DOI: 10.26434/chemrxiv-2024-sfn8p
Mátyás, Pápai
The assessment of electronic structure descriptions utilized in the simulation of ultrafast excited-state dynamics of Fe(II) complexes is presented. Herein, we evaluate the performance of the RPBE, OPBE, BLYP, B3LYP, B3LYP*, CAM-B3LYP, and LC-BLYP (time-dependent) density functional theory (DFT/TD-DFT) methods in full-dimensional trajectory surface hopping (TSH) simulations carried out on linear vibronic coupling (LVC) potentials. We exploit the existence of time-resolved X-ray emission spectroscopy (XES) data for the [Fe(bmip)2]2+ and [Fe(terpy)2]2+ prototypes for dynamics between metal-to-ligand charge transfer (MLCT) and metal-centered (MC) states, which serve as a reference to benchmark the calculations (bmip = 2,6-bis(3-methyl-imidazole-1-ylidine)-pyridine, terpy = 2,2’:6’,2''-terpyridine). The results show that the simulated ultrafast population dynamics between MLCT and MC states with various spin multiplicilities (singlet, triplet, quintet) highly depend on the utilized DFT/TD-DFT method with the percentage of exact (Hartree-Fock) exchange being the governing factor. Importantly, B3LYP* is the only DFT/TD-DFT method reproducing all important aspects of the experimentally resolved dynamics for both complexes, signalling an optimal balance in the description of MLCT-MC energetics. This work demonstrates the power of combining TSH/LVC dynamics simulations with time-resolved experimental reference data to benchmark full-dimensional potential energy surfaces.
{"title":"Simulation of Ultrafast Excited-State Dynamics in Fe(II) Complexes: Assessment of Electronic Structure Descriptions","authors":"Mátyás, Pápai","doi":"10.26434/chemrxiv-2024-sfn8p","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-sfn8p","url":null,"abstract":"The assessment of electronic structure descriptions utilized in the simulation of ultrafast excited-state dynamics of Fe(II) complexes is presented. Herein, we evaluate the performance of the RPBE, OPBE, BLYP, B3LYP, B3LYP*, CAM-B3LYP, and LC-BLYP (time-dependent) density functional theory (DFT/TD-DFT) methods in full-dimensional trajectory surface hopping (TSH) simulations carried out on linear vibronic coupling (LVC) potentials. We exploit the existence of time-resolved X-ray emission spectroscopy (XES) data for the [Fe(bmip)2]2+ and [Fe(terpy)2]2+ prototypes for dynamics between metal-to-ligand charge transfer (MLCT) and metal-centered (MC) states, which serve as a reference to benchmark the calculations (bmip = 2,6-bis(3-methyl-imidazole-1-ylidine)-pyridine, terpy = 2,2’:6’,2''-terpyridine). The results show that the simulated ultrafast population dynamics between MLCT and MC states with various spin multiplicilities (singlet, triplet, quintet) highly depend on the utilized DFT/TD-DFT method with the percentage of exact (Hartree-Fock) exchange being the governing factor. Importantly, B3LYP* is the only DFT/TD-DFT method reproducing all important aspects of the experimentally resolved dynamics for both complexes, signalling an optimal balance in the description of MLCT-MC energetics. This work demonstrates the power of combining TSH/LVC dynamics simulations with time-resolved experimental reference data to benchmark full-dimensional potential energy surfaces.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-18DOI: 10.26434/chemrxiv-2024-ng3ws
Pavlo O., Dral, Yuxinxin, Chen
Machine learning (ML) potentials typically target a single quantum chemical (QC) level while the ML models developed for multi-fidelity learning have not been shown to provide scalable solutions for foundational models. Here we introduce the all-in-one (AIO) ANI model architecture based on multimodal learning which can learn an arbitrary number of QC levels. Our all-in-one learning approach offers a more general and easier-to-use alternative to transfer learning. We use it to train the AIO-ANI-UIP foundational model with the generalization capability comparable to semi-empirical GFN2-xTB and DFT with a double-zeta basis set for organic molecules. We show that the AIO-ANI model can learn across different QC levels ranging from semi-empirical to density functional theory to coupled cluster. We also use AIO models to design the foundational model Δ-AIO-ANI based on Δ-learning with increased accuracy and robustness compared to AIO-ANI-UIP. The code and the foundational models are available at https://github.com/dralgroup/aio-ani; they will be integrated into the universal and updatable AI-enhanced QM (UAIQM) library and made available in the MLatom package so that they can be used online at the XACS cloud computing platform (see https://github.com/dralgroup/mlatom for updates).
{"title":"All-in-one foundational models learning across quantum chemical levels","authors":"Pavlo O., Dral, Yuxinxin, Chen","doi":"10.26434/chemrxiv-2024-ng3ws","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-ng3ws","url":null,"abstract":"Machine learning (ML) potentials typically target a single quantum chemical (QC) level while the ML models developed for multi-fidelity learning have not been shown to provide scalable solutions for foundational models. Here we introduce the all-in-one (AIO) ANI model architecture based on multimodal learning which can learn an arbitrary number of QC levels. Our all-in-one learning approach offers a more general and easier-to-use alternative to transfer learning. We use it to train the AIO-ANI-UIP foundational model with the generalization capability comparable to semi-empirical GFN2-xTB and DFT with a double-zeta basis set for organic molecules. We show that the AIO-ANI model can learn across different QC levels ranging from semi-empirical to density functional theory to coupled cluster. We also use AIO models to design the foundational model Δ-AIO-ANI based on Δ-learning with increased accuracy and robustness compared to AIO-ANI-UIP. The code and the foundational models are available at https://github.com/dralgroup/aio-ani; they will be integrated into the universal and updatable AI-enhanced QM (UAIQM) library and made available in the MLatom package so that they can be used online at the XACS cloud computing platform (see https://github.com/dralgroup/mlatom for updates).","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polyolefins are ubiquitous in consumer products but are notoriously difficult to recycle due to the inherent incompatibility of their common varieties. Existing approaches to addressing this challenge either require complex syntheses or compromise the properties of the parent materials. Here, a new method to compatibilize mixed polyolefins is developed. With a single-step photocatalysis, acid or base functionality can be readily installed onto polyolefins. The combination of acid- and base-modified polyolefins functions as compatibilizers. Incorporating them into polyolefin blends results in excellent mechanical strength, with up to an 82-fold increase in ductility. Importantly, compatibilization can be readily achieved on post-consumer polyolefin mixtures. Furthermore, direct functionalization and compatibilization of polyolefin blends is achieved. This strategy promises to transform polyolefin recycling and will likely find broad applications.
{"title":"Compatibilization of polyolefin blends through acid–base interactions","authors":"Yucheng, Yuan, Jiawei, He, Jiangwei, Liu, Ming-Chi, Wang, Tuhin, Ganguly, John, Santoro, Junpeng, Wang, Jeffery, Byers, Jia, Niu, Mingjiang, Zhong, Dunwei, Wang","doi":"10.26434/chemrxiv-2024-qhsj9","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-qhsj9","url":null,"abstract":"Polyolefins are ubiquitous in consumer products but are notoriously difficult to recycle due to the inherent incompatibility of their common varieties. Existing approaches to addressing this challenge either require complex syntheses or compromise the properties of the parent materials. Here, a new method to compatibilize mixed polyolefins is developed. With a single-step photocatalysis, acid or base functionality can be readily installed onto polyolefins. The combination of acid- and base-modified polyolefins functions as compatibilizers. Incorporating them into polyolefin blends results in excellent mechanical strength, with up to an 82-fold increase in ductility. Importantly, compatibilization can be readily achieved on post-consumer polyolefin mixtures. Furthermore, direct functionalization and compatibilization of polyolefin blends is achieved. This strategy promises to transform polyolefin recycling and will likely find broad applications.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-18DOI: 10.26434/chemrxiv-2024-vxdq4
Yatong, Wang, Geert, Brocks, Ceren, Tayran, Süleyman, Er
Two-dimensional (2D) Janus materials gain increasing attention as water splitting photocatalysts for hydrogen production. We use first-principles calculations to predict a stable 2D Janus $T$-TiNBr structure, with strong near-ultraviolet sunlight absorption and band edges that align favorably with the water redox potentials for oxygen and hydrogen evolution. We show that the optical and electronic properties of $T$-TiNBr can be modulated to a certain extend by applying external uniaxial strain. Explicit calculations of the redox reactions reveal that solar-driven water splitting is viable at the N-side of $T$-TiNBr, while the Br-side requires modifications such as vacancy creation, the application of an external potential, or adjustment of the pH conditions.
{"title":"2D TiNBr as photocatalyst for overall water splitting","authors":"Yatong, Wang, Geert, Brocks, Ceren, Tayran, Süleyman, Er","doi":"10.26434/chemrxiv-2024-vxdq4","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-vxdq4","url":null,"abstract":"Two-dimensional (2D) Janus materials gain increasing attention as water splitting photocatalysts for hydrogen production. We use first-principles calculations to predict a stable 2D Janus $T$-TiNBr structure, with strong near-ultraviolet sunlight absorption and band edges that align favorably with the water redox potentials for oxygen and hydrogen evolution. We show that the optical and electronic properties of $T$-TiNBr can be modulated to a certain extend by applying external uniaxial strain. Explicit calculations of the redox reactions reveal that solar-driven water splitting is viable at the N-side of $T$-TiNBr, while the Br-side requires modifications such as vacancy creation, the application of an external potential, or adjustment of the pH conditions.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-18DOI: 10.26434/chemrxiv-2024-mfpcn
Dhiman, Ray, Valerio, Rizzi
We introduce an enhanced sampling algorithm to obtain converged free energy landscapes of molecular rare events, even when the collective variable (CV) used for biasing is not optimal. Our approach is a combination of the On-the-fly probability enhanced sampling (OPES) and its exploratory variant, OPES Explore (OPESe). We demonstrate the successful application of this combined algorithm on the two-dimensional Wolfe-Quapp potential, ligand-receptor binding in trypsin-benzamidine complex, and folding-unfolding of chignolin. Apart from computing accurate free energy profiles, we can discover additional metastable configurations not distinguished by the sub-optimal CV space. Moreover, we can control the trade-off between accuracy and convergence speed by varying the ratio of the barrier parameters in OPES and OPESe components. The improved efficiency and accuracy of free energy calculation, and the possibility of using generic and intuitive collective variables, make our proposed algorithm particularly promising for the simulation of complex molecular systems.
我们介绍了一种增强采样算法，即使用于偏置的集体变量（CV）不是最佳的，也能获得收敛的分子稀有事件自由能景观。我们的方法是即时概率增强采样（OPES）及其探索变体 OPES Explore（OPESe）的结合。我们展示了这一组合算法在二维 Wolfe-Quapp 势、胰蛋白酶-苯甲脒复合物中配体-受体结合以及木犀草素的折叠-解折上的成功应用。除了计算精确的自由能曲线外，我们还能发现次优 CV 空间无法区分的其他可转移构型。此外，我们还可以通过改变 OPES 和 OPESe 组件中势垒参数的比例来控制精度和收敛速度之间的权衡。自由能计算效率和精度的提高，以及使用通用直观集合变量的可能性，使我们提出的算法在复杂分子系统的模拟中大有可为。
{"title":"Enhanced Sampling with Sub-optimal Collective Variables: Reconciling Accuracy and Convergence Speed","authors":"Dhiman, Ray, Valerio, Rizzi","doi":"10.26434/chemrxiv-2024-mfpcn","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-mfpcn","url":null,"abstract":"We introduce an enhanced sampling algorithm to obtain converged free energy landscapes of molecular rare events, even when the collective variable (CV) used for biasing is not optimal. Our approach is a combination of the On-the-fly probability enhanced sampling (OPES) and its exploratory variant, OPES Explore (OPESe). We demonstrate the successful application of this combined algorithm on the two-dimensional Wolfe-Quapp potential, ligand-receptor binding in trypsin-benzamidine complex, and folding-unfolding of chignolin. Apart from computing accurate free energy profiles, we can discover additional metastable configurations not distinguished by the sub-optimal CV space. Moreover, we can control the trade-off between accuracy and convergence speed by varying the ratio of the barrier parameters in OPES and OPESe components. The improved efficiency and accuracy of free energy calculation, and the possibility of using generic and intuitive collective variables, make our proposed algorithm particularly promising for the simulation of complex molecular systems.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The development of chemoselective defluorination reactions is highly desirable due to the exceptional stability of the C–F bond compared to other functional groups. Recent advances in photocatalysis have enabled cataytic single-electron transfer (SET) processes, offering an alternative to stoichiometric methods that rely on strong reducing agents. However, these strategies have primarily focused on trifluoromethyl substrates, with limited success for compounds containing fewer fluorine atoms, which are inherently more resistant to SET. Herein, we report a novel defluorination strategy for α-fluorocarbonyl compounds, employing zirconocene and photoredox catalysis. Our method leverages the strong fluorine affinity of zirconocene and bypassed reliance on reduction potential, focusing instead on the bond dissociation energy of the fluorinated molecules. This methodology offers a complementary ap-proach for catalytic C–F bond cleavage under visible-light conditions.
与其他官能团相比，C-F 键具有极高的稳定性，因此开发化学选择性脱氟反应非常有必要。光催化技术的最新进展实现了催化单电子转移（SET）过程，为依赖强还原剂的化学计量法提供了替代方案。然而，这些策略主要集中在三氟甲基底物上，而对于含氟原子较少的化合物则成效有限，因为这些化合物对 SET 本身具有更强的抵抗力。在此，我们报告了一种新型的α-氟羰基化合物脱氟方法，该方法采用锆烯和光氧化催化。我们的方法利用了二茂锆的强氟亲和力，绕过了对还原电位的依赖，转而关注氟化分子的键解离能。这种方法为在可见光条件下催化 C-F 键裂解提供了一种补充方法。
{"title":"Reversing the Chemoselectivity in Photocatalytic C–F Bond Cleavage Enabled by Zirconocene and Photoredox Catalysis","authors":"Junichiro, Yamaguchi, Haruki, Takimoto, Kazuhiro, Aida, Yoshio, Nishimoto, Daisuke, Yokogawa, Eisuke, Ota","doi":"10.26434/chemrxiv-2024-ssj00","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-ssj00","url":null,"abstract":"The development of chemoselective defluorination reactions is highly desirable due to the exceptional stability of the C–F bond compared to other functional groups. Recent advances in photocatalysis have enabled cataytic single-electron transfer (SET) processes, offering an alternative to stoichiometric methods that rely on strong reducing agents. However, these strategies have primarily focused on trifluoromethyl substrates, with limited success for compounds containing fewer fluorine atoms, which are inherently more resistant to SET. Herein, we report a novel defluorination strategy for α-fluorocarbonyl compounds, employing zirconocene and photoredox catalysis. Our method leverages the strong fluorine affinity of zirconocene and bypassed reliance on reduction potential, focusing instead on the bond dissociation energy of the fluorinated molecules. This methodology offers a complementary ap-proach for catalytic C–F bond cleavage under visible-light conditions.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The global emergence of COVID-19, caused by SARS-CoV-2, has underscored the critical need for effective antivirals against coronaviruses. The 3-chymotrypsin-like protease (3CLpro) of coronavirus has been a primary target for drug development due to its critical role across various coronaviruses. Following our initial report, this study focuses on the structure-based optimization of 3CLpro covalent inhibitors. With the guidance of molecular docking and covalent binding parameters measured from an innovative isothermal titration calorimetry-kinetic competition (ITC-KC) assay, we optimized and synthesized series of potent covalent inhibitors with antiviral activity in cell-based assays.
{"title":"Structure-Based Optimization and Biological Evaluation of SARS-CoV-2 3CLpro Covalent Inhibitors","authors":"Nicolas, Moitessier, Guanyu, Wang, Julia, Stille, Richard, Boulon, Christopher, Hennecker, Xiaocong, Zhang, Nicole, Blaine, Steven, Laplante, Anthony, Mittermaier","doi":"10.26434/chemrxiv-2024-091mt","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-091mt","url":null,"abstract":"The global emergence of COVID-19, caused by SARS-CoV-2, has underscored the critical need for effective antivirals against coronaviruses. The 3-chymotrypsin-like protease (3CLpro) of coronavirus has been a primary target for drug development due to its critical role across various coronaviruses. Following our initial report, this study focuses on the structure-based optimization of 3CLpro covalent inhibitors. With the guidance of molecular docking and covalent binding parameters measured from an innovative isothermal titration calorimetry-kinetic competition (ITC-KC) assay, we optimized and synthesized series of potent covalent inhibitors with antiviral activity in cell-based assays.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have evaluated the antibacterial activity of the essential oil of the leaves of Coreopsis lanceolata (CL-EO) collected in southeastern Brazil. against a representative panel of cariogenic bacteria. The activity was evaluated in terms of its Minimum Inhibitory Concentration (MIC) values. CL-EO displays moderate activity against Streptococcus mutans, S. sanguinis, S. salivarus, S. sobrinus, Lactobacillus paracasei, and Enterococcus faecalis (MIC = 1000 µg/mL) and strong activity against S. mitis (MIC = 500 µg/mL). We have identified 1,11-tridecadiene-3,5,7,9-tetrayne (48.9%), β-bisabolene (22.8%), germacrene D (9.2%), and globulol (4.6%) as the major compounds in CL-EO. This is the first report on the chemical composition of the essential oil obtained from C. lanceolata leaves.
{"title":"Chemical composition and antibacterial activity of the essential oil of Coreopsis lanceolata leaves","authors":"Antônio, Crotti, Richard, Lima, Ana Carla, Colli, Sara, Souza, Milton, Groppo, Carlos, Martins","doi":"10.26434/chemrxiv-2024-dk7v6","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-dk7v6","url":null,"abstract":"We have evaluated the antibacterial activity of the essential oil of the leaves of Coreopsis lanceolata (CL-EO) collected in southeastern Brazil. against a representative panel of cariogenic bacteria. The activity was evaluated in terms of its Minimum Inhibitory Concentration (MIC) values. CL-EO displays moderate activity against Streptococcus mutans, S. sanguinis, S. salivarus, S. sobrinus, Lactobacillus paracasei, and Enterococcus faecalis (MIC = 1000 µg/mL) and strong activity against S. mitis (MIC = 500 µg/mL). We have identified 1,11-tridecadiene-3,5,7,9-tetrayne (48.9%), β-bisabolene (22.8%), germacrene D (9.2%), and globulol (4.6%) as the major compounds in CL-EO. This is the first report on the chemical composition of the essential oil obtained from C. lanceolata leaves.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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