Pub Date : 2024-09-26DOI: 10.1016/j.jmgm.2024.108875
Cytochrome P450 (CYP) enzymes play essential roles in the synthesis and metabolic activation of physiologically active substances. CYP has a prosthetic heme (iron protoporphyrin IX) in its active center, where Fe ion (heme-Fe) is deeply involved in enzymatic reactions of CYP. To precisely describe the structure and electronic states around heme-Fe, we modified the force fields (FFs) around heme-Fe in molecular mechanics (MM) simulations and conducted ab initio fragment molecular orbital (FMO) calculations for the CYP–ligand complex. To describe the coordination bond between heme-Fe and its coordinated ligand (ketoconazole), we added FF between heme-Fe and the N atom of ketoconazole, and then the structure of the complex was optimized using the modified FF. Its adequacy was confirmed by comparing the MM-optimized structure with the X-ray crystal one of the CYP–ketoconazole complex. We also performed 100 ns molecular dynamics simulations and revealed that the coordination bonds around heme-Fe were maintained even at 310 K and that the CYP–ketoconazole structure was kept similar to the X-ray structure. Furthermore, we investigated the electronic states of the complex using the ab initio FMO method to identify the CYP residues and parts of ketoconazole that contribute to strong binding between CYP and ketoconazole. The present procedure of constructing FF between heme-Fe and ketoconazole can be applicable to other CYP–ligand complexes, and the modified FF can provide their accurate structures useful for predicting the specific interactions between CYP and its ligands.
细胞色素 P450（CYP）酶在生理活性物质的合成和代谢活化过程中发挥着重要作用。CYP 的活性中心有一个修复血红素（铁原卟啉 IX），其中的铁离子（血红素-铁）深度参与了 CYP 的酶促反应。为了精确描述血红素-铁周围的结构和电子状态，我们在分子力学（MM）模拟中修改了血红素-铁周围的力场（FFs），并对 CYP 配体复合物进行了 ab initio 片段分子轨道（FMO）计算。为了描述血红素-铁与其配位体（酮康唑）之间的配位键，我们在血红素-铁与酮康唑的 N 原子之间添加了 FF，然后使用修改后的 FF 对复合物结构进行了优化。通过将 MM 优化后的结构与 CYP-酮康唑复合物的 X 射线晶体结构进行比较，证实了 MM 结构的适当性。我们还进行了 100 ns 的分子动力学模拟，结果表明，即使在 310 K 的温度下，血红素-铁周围的配位键仍然保持不变，CYP-酮康唑的结构也与 X 射线结构相似。此外，我们还利用 ab initio FMO 方法研究了复合物的电子态，以确定 CYP 残基和酮康唑中有助于 CYP 与酮康唑强结合的部分。本研究构建血红素-铁和酮康唑之间的 FF 的过程可适用于其他 CYP 配体复合物，修饰后的 FF 可提供其精确结构，有助于预测 CYP 与其配体之间的特定相互作用。
{"title":"Modification of MM force fields around heme-Fe in the CYP–ligand complex and ab initio FMO calculations for the complex","authors":"","doi":"10.1016/j.jmgm.2024.108875","DOIUrl":"10.1016/j.jmgm.2024.108875","url":null,"abstract":"<div><div>Cytochrome P450 (CYP) enzymes play essential roles in the synthesis and metabolic activation of physiologically active substances. CYP has a prosthetic heme (iron protoporphyrin IX) in its active center, where Fe ion (heme-Fe) is deeply involved in enzymatic reactions of CYP. To precisely describe the structure and electronic states around heme-Fe, we modified the force fields (FFs) around heme-Fe in molecular mechanics (MM) simulations and conducted <em>ab initio</em> fragment molecular orbital (FMO) calculations for the CYP–ligand complex. To describe the coordination bond between heme-Fe and its coordinated ligand (ketoconazole), we added FF between heme-Fe and the N atom of ketoconazole, and then the structure of the complex was optimized using the modified FF. Its adequacy was confirmed by comparing the MM-optimized structure with the X-ray crystal one of the CYP–ketoconazole complex. We also performed 100 ns molecular dynamics simulations and revealed that the coordination bonds around heme-Fe were maintained even at 310 K and that the CYP–ketoconazole structure was kept similar to the X-ray structure. Furthermore, we investigated the electronic states of the complex using the <em>ab initio</em> FMO method to identify the CYP residues and parts of ketoconazole that contribute to strong binding between CYP and ketoconazole. The present procedure of constructing FF between heme-Fe and ketoconazole can be applicable to other CYP–ligand complexes, and the modified FF can provide their accurate structures useful for predicting the specific interactions between CYP and its ligands.</div></div>","PeriodicalId":16361,"journal":{"name":"Journal of molecular graphics & modelling","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142372075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-24DOI: 10.1016/j.jmgm.2024.108873
The outbreak of pneumonia caused by the novel coronavirus (SARS-CoV-2) has presented a challenge to public health. The identification and development of effective antiviral drugs is essential. The main protease (3CLpro) plays an important role in the viral replication of SARS-CoV-2 and is considered to be an effective therapeutic target. In this study, according to the principle of drug repurposing, a variety of antiviral drugs commonly used were studied by molecular docking and molecular dynamics (MD) simulations to obtain potential inhibitors of main proteases. 24 antiviral drugs were docked with 5 potential action sites of 3CLpro, and the drugs with high binding strength were further simulated by MD and the molecular mechanics Poisson–Boltzmann surface area (MM-PBSA) binding free energy calculations. The results showed that the drugs with high flexibility could bind to 3CLpro better than those with low flexibility. The interaction mechanism between antiviral drugs and main protease was analyzed in detail by calculating the root mean square displacement (RMSD), root mean square fluctuation (RMSF) and interaction residues properties. The results showed that the six drugs with high flexibility (Remdesivir, Simnotrelvir, Sofosbuvir, Ledipasvir, Indinavir and Raltegravir) had strong binding strength with 3CLpro, and the last four antiviral drugs can be used as potential candidates for main protease inhibitors.
{"title":"Evaluation of inhibition effect and interaction mechanism of antiviral drugs on main protease of novel coronavirus: Molecular docking and molecular dynamics studies","authors":"","doi":"10.1016/j.jmgm.2024.108873","DOIUrl":"10.1016/j.jmgm.2024.108873","url":null,"abstract":"<div><div>The outbreak of pneumonia caused by the novel coronavirus (SARS-CoV-2) has presented a challenge to public health. The identification and development of effective antiviral drugs is essential. The main protease (3CLpro) plays an important role in the viral replication of SARS-CoV-2 and is considered to be an effective therapeutic target. In this study, according to the principle of drug repurposing, a variety of antiviral drugs commonly used were studied by molecular docking and molecular dynamics (MD) simulations to obtain potential inhibitors of main proteases. 24 antiviral drugs were docked with 5 potential action sites of 3CLpro, and the drugs with high binding strength were further simulated by MD and the molecular mechanics Poisson–Boltzmann surface area (MM-PBSA) binding free energy calculations. The results showed that the drugs with high flexibility could bind to 3CLpro better than those with low flexibility. The interaction mechanism between antiviral drugs and main protease was analyzed in detail by calculating the root mean square displacement (RMSD), root mean square fluctuation (RMSF) and interaction residues properties. The results showed that the six drugs with high flexibility (Remdesivir, Simnotrelvir, Sofosbuvir, Ledipasvir, Indinavir and Raltegravir) had strong binding strength with 3CLpro, and the last four antiviral drugs can be used as potential candidates for main protease inhibitors.</div></div>","PeriodicalId":16361,"journal":{"name":"Journal of molecular graphics & modelling","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-21DOI: 10.1016/j.jmgm.2024.108871
In this study, molecular dynamics simulation was used to predict the molecular diffusion coefficient of acetic acid and acetone in water, toluene, and benzene. The results showed that COMPASS was the best force field to optimize the atoms and structure of molecules, and the results were compared with experimental equations. The Arrhenius behavior of the molecular diffusion coefficient was investigated at three temperatures. The extraction of acetic acid and acetone from water was investigated using two solvents, toluene, and benzene, with and without SiO2 nanoparticles. The relative concentration change diagram was drawn for three cases without and with SiO2 nanoparticles. To quantitatively examine the results, extraction efficiency, selectivity, and distribution coefficient were calculated. The extraction efficiency of acetone from water by benzene in the absence of silica nanoparticles was 65.748 %, this value in the presence of SiO2 nanoparticles with a concentration of 0.2231 wt% was 72.45 % due to the Brownian motion of the nanoparticles, which increased the mass transfer and as a result, the extraction efficiency. With the further increase of nanoparticles up to 1.7573 wt%, the extraction efficiency decreased to 61.276 %, which can be attributed to the accumulation of silica nanoparticles and the decrease in the free movement of nanoparticles.
{"title":"Investigation of solvent extraction of acetic acid and acetone from water in the presence of SiO2 nanoparticles using molecular dynamics simulation","authors":"","doi":"10.1016/j.jmgm.2024.108871","DOIUrl":"10.1016/j.jmgm.2024.108871","url":null,"abstract":"<div><div>In this study, molecular dynamics simulation was used to predict the molecular diffusion coefficient of acetic acid and acetone in water, toluene, and benzene. The results showed that COMPASS was the best force field to optimize the atoms and structure of molecules, and the results were compared with experimental equations. The Arrhenius behavior of the molecular diffusion coefficient was investigated at three temperatures. The extraction of acetic acid and acetone from water was investigated using two solvents, toluene, and benzene, with and without SiO<sub>2</sub> nanoparticles. The relative concentration change diagram was drawn for three cases without and with SiO<sub>2</sub> nanoparticles. To quantitatively examine the results, extraction efficiency, selectivity, and distribution coefficient were calculated. The extraction efficiency of acetone from water by benzene in the absence of silica nanoparticles was 65.748 %, this value in the presence of SiO<sub>2</sub> nanoparticles with a concentration of 0.2231 wt% was 72.45 % due to the Brownian motion of the nanoparticles, which increased the mass transfer and as a result, the extraction efficiency. With the further increase of nanoparticles up to 1.7573 wt%, the extraction efficiency decreased to 61.276 %, which can be attributed to the accumulation of silica nanoparticles and the decrease in the free movement of nanoparticles.</div></div>","PeriodicalId":16361,"journal":{"name":"Journal of molecular graphics & modelling","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1016/j.jmgm.2024.108863
The water, alcohols, and their binary mixtures are widely used in molecular simulations. However, the Dreiding force field lacks a generally accepted method for assigning atomic charges to these solvents during simulations. In this study, we propose a universal charge assignment for water and eight water-miscible alcohols in Dreiding. Through extensive molecular simulations, we demonstrate the good accuracy of our charge assignments in displaying characteristic of these solvents and their mixtures, including liquid density and structure. Moreover, we investigate equilibrium snapshot, radial distribution function, coordination number and hydrogen bonding, all of which confirm the miscibility of alcohols with water or ethanol. Notably, we reveal that the structure diversity among different mixtures can be attributed to distinctive characteristic of alcohols, including molecular volume, as well as the number and position of hydroxyls.
{"title":"Exploring the structural feature of water, alcohols, and their binary mixtures with concrete atomic charge assignments in Dreiding forcefield","authors":"","doi":"10.1016/j.jmgm.2024.108863","DOIUrl":"10.1016/j.jmgm.2024.108863","url":null,"abstract":"<div><div>The water, alcohols, and their binary mixtures are widely used in molecular simulations. However, the Dreiding force field lacks a generally accepted method for assigning atomic charges to these solvents during simulations. In this study, we propose a universal charge assignment for water and eight water-miscible alcohols in Dreiding. Through extensive molecular simulations, we demonstrate the good accuracy of our charge assignments in displaying characteristic of these solvents and their mixtures, including liquid density and structure. Moreover, we investigate equilibrium snapshot, radial distribution function, coordination number and hydrogen bonding, all of which confirm the miscibility of alcohols with water or ethanol. Notably, we reveal that the structure diversity among different mixtures can be attributed to distinctive characteristic of alcohols, including molecular volume, as well as the number and position of hydroxyls.</div></div>","PeriodicalId":16361,"journal":{"name":"Journal of molecular graphics & modelling","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142307909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1016/j.jmgm.2024.108869
Oat contains a large amount of polysaccharides and peptides, among which oat peptides have the function of reducing blood sugar levels in the body. This paper reviewed the peptides obtained from oat extraction and identification from literature and constructed the corresponding oat peptide database. Based on the DPP4 protein, a virtual screening of the peptide database was performed. One hundred nanosecond molecular dynamics simulations were performed for the six peptides obtained from the screening. The interaction information between different peptide molecules and DPP4 was analyzed from the stable binding conformations after the simulation, and the binding free energy between different peptide molecules and DPP4 was calculated. The results show that the peptide molecules obtained from the virtual screening can all stably bind to the DPP4 protein, among which two peptide molecules have relatively strong affinity with DPP4 and can be used as lead molecules for the subsequent design and modification of DPP4 inhibitors. The simulation results are informative for a deeper understanding of the structural characteristics of DPP4 and the molecular recognition mechanism between DPP4 and oat peptides.
{"title":"Virtual screening, molecular docking, and molecular dynamics simulation studies on the hypoglycemic function of oat peptides","authors":"","doi":"10.1016/j.jmgm.2024.108869","DOIUrl":"10.1016/j.jmgm.2024.108869","url":null,"abstract":"<div><div>Oat contains a large amount of polysaccharides and peptides, among which oat peptides have the function of reducing blood sugar levels in the body. This paper reviewed the peptides obtained from oat extraction and identification from literature and constructed the corresponding oat peptide database. Based on the DPP4 protein, a virtual screening of the peptide database was performed. One hundred nanosecond molecular dynamics simulations were performed for the six peptides obtained from the screening. The interaction information between different peptide molecules and DPP4 was analyzed from the stable binding conformations after the simulation, and the binding free energy between different peptide molecules and DPP4 was calculated. The results show that the peptide molecules obtained from the virtual screening can all stably bind to the DPP4 protein, among which two peptide molecules have relatively strong affinity with DPP4 and can be used as lead molecules for the subsequent design and modification of DPP4 inhibitors. The simulation results are informative for a deeper understanding of the structural characteristics of DPP4 and the molecular recognition mechanism between DPP4 and oat peptides.</div></div>","PeriodicalId":16361,"journal":{"name":"Journal of molecular graphics & modelling","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1016/j.jmgm.2024.108870
Amide derivative receptors have been designed to investigate the oxoanion complexation ability via hydrogen and halogen bond interactions. Structural, energetic and electronic properties of nitroisophthalamide receptors, i.e., di(benzyl)− (R1), di(hexafluoro)− (R2), di(chloro−,tetrafluoro)− (R3), di(hexachloro)−(R4), di(fluoro−,tetrachloro)−nitroisophthalamide (R5), and their complexes with C2H3O2−, C7H5O2−, NO3−, H2PO4−, and ClO4− oxoanions were computed and obtained using the density functional theory calculations at the B3LYP/6-31G(d,p) theoretical level in gas phase. According to the computed results, all of oxoanions can form the stable complexes with amide receptors R1−R5 via exothermic process in which receptor R1 is found to interact with oxoanions through hydrogen bonds whereas the receptors R2−R5 are found to interact with oxoanion through both of hydrogen and halogen bonds. It is clearly seen that acetate ion displays the strongest complexation interaction with all receptors compared to the other oxoanions. In addition, electronic properties of receptors R1−R5 in both gas and DMSO phases are modified after complexation with oxoanions. Therefore, the designed amide receptors may be potentially used for oxoanion sensing application.
{"title":"Oxoanion complexation of nitroisophthalamide receptors: Insights from the DFT calculations","authors":"","doi":"10.1016/j.jmgm.2024.108870","DOIUrl":"10.1016/j.jmgm.2024.108870","url":null,"abstract":"<div><div>Amide derivative receptors have been designed to investigate the oxoanion complexation ability via hydrogen and halogen bond interactions. Structural, energetic and electronic properties of nitroisophthalamide receptors, i.e., di(benzyl)− (<strong>R1</strong>), di(hexafluoro)− (<strong>R2</strong>), di(chloro−,tetrafluoro)− (<strong>R3</strong>), di(hexachloro)−(<strong>R4</strong>), di(fluoro−,tetrachloro)−nitroisophthalamide (<strong>R5</strong>), and their complexes with C<sub>2</sub>H<sub>3</sub>O<sub>2</sub><sup>−</sup>, C<sub>7</sub>H<sub>5</sub>O<sub>2</sub><sup>−</sup>, NO<sub>3</sub><sup>−</sup>, H<sub>2</sub>PO<sub>4</sub><sup>−</sup>, and ClO<sub>4</sub><sup>−</sup> oxoanions were computed and obtained using the density functional theory calculations at the B3LYP/6-31G(d,p) theoretical level in gas phase. According to the computed results, all of oxoanions can form the stable complexes with amide receptors <strong>R1</strong>−<strong>R5</strong> via exothermic process in which receptor <strong>R1</strong> is found to interact with oxoanions through hydrogen bonds whereas the receptors <strong>R2</strong>−<strong>R5</strong> are found to interact with oxoanion through both of hydrogen and halogen bonds. It is clearly seen that acetate ion displays the strongest complexation interaction with all receptors compared to the other oxoanions. In addition, electronic properties of receptors <strong>R1</strong>−<strong>R5</strong> in both gas and DMSO phases are modified after complexation with oxoanions. Therefore, the designed amide receptors may be potentially used for oxoanion sensing application.</div></div>","PeriodicalId":16361,"journal":{"name":"Journal of molecular graphics & modelling","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-18DOI: 10.1016/j.jmgm.2024.108867
The behavior of metal ions is commonly studied in pure solvent although, in our daily life, these metals are involved in mixtures of solvents. In the present study, we investigated structures, relative stabilities and temperature dependance of solvated ferrous ion in water–ammonia mixture solvent at 0 K and at various temperatures ranging from 25 K to 400 K. All the calculations are performed at the MN15 level of theory associated with the aug-cc-pVDZ basis set. For deep understanding of binding patterns in solvated ferrous ion in water–ammonia mixture solvent, noncovalent interactions are presented based on the QTAIM analysis using AIMAll. Our results prove that the ferrous ion is more stable when it is solvated by ammonia instead of water. In addition, hydrogen bonds are weakened by the presence of ammonia molecules. The temperature dependence of the different obtained geometries indicates that from ( is the sum of water and ammonia molecules around the ferrous ion), when the number of water molecules is almost equal to that of ammonia, the structures with coordination number 5 are dominant. However, the coordination number is six when there are a maximum water molecules (rich water solution) or maximum ammonia molecules (rich ammonia solution) around the ferrous ion (for ). The QTAIM analysis shows that there are two coordination bondings and four hydrogen bondings. Furthermore, it is found that the FeN coordination bondings are stronger than the FeO confirming that the ferrous ion prefers to be solvated by ammonia instead of water.
金属离子的行为通常在纯溶剂中进行研究，但在我们的日常生活中，这些金属会与混合溶剂发生作用。在本研究中，我们研究了水氨混合溶剂中溶解的亚铁离子在 0 K 和 25 K 至 400 K 不同温度下的结构、相对稳定性和温度依赖性。为了深入理解水-氨混合溶剂中溶解的亚铁离子的结合模式，我们基于使用 AIMAll 进行的 QTAIM 分析提出了非共价相互作用。我们的研究结果证明，当亚铁离子被氨水而不是水溶解时，其稳定性更高。此外，氢键也会因为氨分子的存在而减弱。不同几何形状的温度依赖性表明，从 s=6（s 是亚铁离子周围水分子和氨分子的总和）开始，当水分子数几乎等于氨分子数时，配位数为 5 的结构占主导地位。然而，当亚铁离子周围的水分子数最多（富水溶液）或氨分子数最多（富氨溶液）时（s≥6），配位数为 6。QTAIM 分析表明，存在两个配位键和四个氢键。此外，研究还发现，Fe2+⋯N 配位键比 Fe2+⋯O 强，这证实了亚铁离子更喜欢被氨溶解，而不是被水溶解。
{"title":"Clusters of solvated ferrous ion in water–ammonia mixture: Structures and noncovalent interactions","authors":"","doi":"10.1016/j.jmgm.2024.108867","DOIUrl":"10.1016/j.jmgm.2024.108867","url":null,"abstract":"<div><div>The behavior of metal ions is commonly studied in pure solvent although, in our daily life, these metals are involved in mixtures of solvents. In the present study, we investigated structures, relative stabilities and temperature dependance of solvated ferrous ion in water–ammonia mixture solvent at 0<!--> <!-->K and at various temperatures ranging from 25<!--> <!-->K to 400<!--> <!-->K. All the calculations are performed at the MN15 level of theory associated with the aug-cc-pVDZ basis set. For deep understanding of binding patterns in solvated ferrous ion in water–ammonia mixture solvent, noncovalent interactions are presented based on the QTAIM analysis using AIMAll. Our results prove that the ferrous ion is more stable when it is solvated by ammonia instead of water. In addition, hydrogen bonds are weakened by the presence of ammonia molecules. The temperature dependence of the different obtained geometries indicates that from <span><math><mrow><mi>s</mi><mo>=</mo><mn>6</mn></mrow></math></span> (<span><math><mi>s</mi></math></span> is the sum of water and ammonia molecules around the ferrous ion), when the number of water molecules is almost equal to that of ammonia, the structures with coordination number 5 are dominant. However, the coordination number is six when there are a maximum water molecules (rich water solution) or maximum ammonia molecules (rich ammonia solution) around the ferrous ion (for <span><math><mrow><mi>s</mi><mo>≥</mo><mn>6</mn></mrow></math></span>). The QTAIM analysis shows that there are two coordination bondings and four hydrogen bondings. Furthermore, it is found that the Fe<span><math><mrow><msup><mrow></mrow><mrow><mn>2</mn><mo>+</mo></mrow></msup><mo>⋯</mo><mspace></mspace></mrow></math></span>N coordination bondings are stronger than the Fe<span><math><mrow><msup><mrow></mrow><mrow><mn>2</mn><mo>+</mo></mrow></msup><mo>⋯</mo><mspace></mspace></mrow></math></span>O confirming that the ferrous ion prefers to be solvated by ammonia instead of water.</div></div>","PeriodicalId":16361,"journal":{"name":"Journal of molecular graphics & modelling","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-16DOI: 10.1016/j.jmgm.2024.108868
Hydrate-based CO2 storage is a cost-effective and environmentally friendly approach to reduce carbon emission, and the addition of hydrate promoters has shown a promising avenue for enhancing CO2 hydrate formation. In this work, the promotion mechanism and promotion performance of five different hydrate promoters (denoted as DIOX, CP, THF, THP, and CH) were investigated and compared by first-principles calculations and molecular dynamics simulations. The results show that the hydrate promoters prefer to singly occupy 51264 cages of the sII hydrate, and CO2 molecules can singly occupy 512 cage or multiply occupy 51264 cages. The cohesive energy density indicates that the optimum CO2 storage capacity can reach up to ∼28 wt%. The stabilization effects of hydrate promoters on the hydrate stability should follow the order of CP > CH > DIOX > THF ≈ THP. The hydrate promoters can increase the water-water interactions, and the molecular diffusivity shows that the dynamic stability of the hydrates is THP ≈ CH > CP > DIOX > THF. Further, the hydrate promoters can accelerate the hydrate formation kinetics, which reduce the induction time and increase the nucleation and growth process.
{"title":"Molecular insights into the performance of promoters for carbon dioxide hydrate","authors":"","doi":"10.1016/j.jmgm.2024.108868","DOIUrl":"10.1016/j.jmgm.2024.108868","url":null,"abstract":"<div><p>Hydrate-based CO<sub>2</sub> storage is a cost-effective and environmentally friendly approach to reduce carbon emission, and the addition of hydrate promoters has shown a promising avenue for enhancing CO<sub>2</sub> hydrate formation. In this work, the promotion mechanism and promotion performance of five different hydrate promoters (denoted as DIOX, CP, THF, THP, and CH) were investigated and compared by first-principles calculations and molecular dynamics simulations. The results show that the hydrate promoters prefer to singly occupy 5<sup>12</sup>6<sup>4</sup> cages of the sII hydrate, and CO<sub>2</sub> molecules can singly occupy 5<sup>12</sup> cage or multiply occupy 5<sup>12</sup>6<sup>4</sup> cages. The cohesive energy density indicates that the optimum CO<sub>2</sub> storage capacity can reach up to ∼28 wt%. The stabilization effects of hydrate promoters on the hydrate stability should follow the order of CP > CH > DIOX > THF ≈ THP. The hydrate promoters can increase the water-water interactions, and the molecular diffusivity shows that the dynamic stability of the hydrates is THP ≈ CH > CP > DIOX > THF. Further, the hydrate promoters can accelerate the hydrate formation kinetics, which reduce the induction time and increase the nucleation and growth process.</p></div>","PeriodicalId":16361,"journal":{"name":"Journal of molecular graphics & modelling","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142241432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-14DOI: 10.1016/j.jmgm.2024.108866
This study presents a computational investigation into the mechanistic pathway and the linker units involved in forming the zwitterionic 1,2-anti-addition product of non-conjugated diacetylenes, di(propargyl)ether (DPE), di(prop-2yn-1yl)sulfane (DPS) and 1,6-Heptadiyne (HD) catalyzed by the inter-molecular phosphine/borane frustrated Lewis pairs (FLPs), i.e., PPh2[C6H3(CF3)2](P-CF)/[B(C6F5)3]([B]) and P(o-tolyl)3(P-tol)/[B(C6F5)3]([B]). The potential energy surface (PES) calculations reveal that the anti-addition of P-CF to the internal C-atoms of acetylene units is energetically more favored than that of the addition of P-tol in DPE, DPS, and HD by ∼10.0, ∼9.2, and ∼6.0 kcal/mol, respectively. The calculations performed with DPE contain “—O—,” linker unit exhibits superior reactivity than DPS and HD, which suggests the electronegativity of linkers plays a significant role and facilitates the addition of Lewis bases. The higher electronegativity of linker units enables the 1,2-addition reaction by lowering the free energy activation barriers, as observed in the DFT calculations. The Molecular Electrostatic Potential (MESP) study shows that the electrostatic interactions favor the addition of P-CF to the active acetylene positions (C5/C4/C4) of [B]-DPE/DPS/HD-π complexes than the P-tol. The Distortion/Interaction (D/I) analysis reveals that transition states involving P-CF (TS1, TS3, and TS5) exhibit more interaction energy (ΔEInt) and less distortion energies (ΔEd) than that of the P-tol (TS2, TS4, and TS6). Further, the Energy Decomposition Analysis (EDA) also rationalizes the preferential approach of the electron-deficient Lewis base over the electron-rich one on the basis of the significant contribution of orbital interaction energies (ΔEorbital) in the cases of P-CF; TS1, TS3, and TS5. This study suggests that the electronic effects of substrates and the FLPs are crucial to facilitate the desired products formed with non-conjugated terminal alkynes.
{"title":"The role of linkers and frustrated lewis pairs catalysts in the formation of zwitterionic 1,2-anti-addition product with non-conjugated terminal diacetylenes: A computational study","authors":"","doi":"10.1016/j.jmgm.2024.108866","DOIUrl":"10.1016/j.jmgm.2024.108866","url":null,"abstract":"<div><p>This study presents a computational investigation into the mechanistic pathway and the linker units involved in forming the zwitterionic 1,2-<em>anti</em>-addition product of non-conjugated diacetylenes, di(propargyl)ether (<strong>DPE</strong>), di(prop-2yn-1yl)sulfane (<strong>DPS</strong>) and 1,6-Heptadiyne (<strong>HD</strong>) catalyzed by the inter-molecular phosphine/borane frustrated Lewis pairs (FLPs), i.e., PPh<sub>2</sub>[C<sub>6</sub>H<sub>3</sub>(CF<sub>3</sub>)<sub>2</sub>](<strong>P-CF</strong>)/[B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>](<strong>[B]</strong>) and P(o-tolyl)<sub>3</sub>(<strong>P-tol</strong>)/[B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>](<strong>[B]</strong>). The potential energy surface (PES) calculations reveal that the <em>anti</em>-addition of <strong>P-CF</strong> to the internal C-atoms of acetylene units is energetically more favored than that of the addition of <strong>P-tol</strong> in <strong>DPE</strong>, <strong>DPS</strong>, and <strong>HD</strong> by ∼10.0, ∼9.2, and ∼6.0 kcal/mol, respectively. The calculations performed with <strong>DPE</strong> contain “—O—,” linker unit exhibits superior reactivity than <strong>DPS</strong> and <strong>HD</strong>, which suggests the electronegativity of linkers plays a significant role and facilitates the addition of Lewis bases. The higher electronegativity of linker units enables the 1,2-addition reaction by lowering the free energy activation barriers, as observed in the DFT calculations. The Molecular Electrostatic Potential (MESP) study shows that the electrostatic interactions favor the addition of <strong>P-CF</strong> to the active acetylene positions (<strong>C5</strong>/<strong>C4</strong>/<strong>C4</strong>) of <strong>[B]</strong>-<strong>DPE/DPS/HD</strong>-π complexes than the <strong>P-tol</strong>. The Distortion/Interaction (D/I) analysis reveals that transition states involving <strong>P-CF</strong> (TS1, TS3, and TS5) exhibit more interaction energy (ΔE<sub>Int</sub>) and less distortion energies (ΔE<sup>d</sup>) than that of the <strong>P-tol</strong> (TS2, TS4, and TS6). Further, the Energy Decomposition Analysis (EDA) also rationalizes the preferential approach of the electron-deficient Lewis base over the electron-rich one on the basis of the significant contribution of orbital interaction energies (ΔE<sub>orbital</sub>) in the cases of <strong>P-CF</strong>; TS1, TS3, and TS5. This study suggests that the electronic effects of substrates and the FLPs are crucial to facilitate the desired products formed with non-conjugated terminal alkynes.</p></div>","PeriodicalId":16361,"journal":{"name":"Journal of molecular graphics & modelling","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142241298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-12DOI: 10.1016/j.jmgm.2024.108864
Ethanol and water are the primary components of liquor. In this study, molecular dynamics (MD) simulations and density functional theory (DFT) were used to model ethanol-water clusters and infer possible structures of ethanol-water solutions. Nuclear magnetic resonance (NMR) and density of states analysis were employed to confirm the existence of clusters and further describe their properties. By comparing binding energies and calculating coordination numbers, we found that the ethanol-water solution with a molecular ratio of 1:2 forms three stable clusters. Under ideal conditions, the cluster ratio is approximately 1:1:6. Generally, the clusters undergo continuous splitting and recombination.
{"title":"Investigation of liquor microstructure (ethanol-water clusters): Molecular dynamics simulation and density functional theory","authors":"","doi":"10.1016/j.jmgm.2024.108864","DOIUrl":"10.1016/j.jmgm.2024.108864","url":null,"abstract":"<div><p>Ethanol and water are the primary components of liquor. In this study, molecular dynamics (MD) simulations and density functional theory (DFT) were used to model ethanol-water clusters and infer possible structures of ethanol-water solutions. Nuclear magnetic resonance (NMR) and density of states analysis were employed to confirm the existence of clusters and further describe their properties. By comparing binding energies and calculating coordination numbers, we found that the ethanol-water solution with a molecular ratio of 1:2 forms three stable clusters. Under ideal conditions, the cluster ratio is approximately 1:1:6. Generally, the clusters undergo continuous splitting and recombination.</p></div>","PeriodicalId":16361,"journal":{"name":"Journal of molecular graphics & modelling","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142241975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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