Escherichia coli β-galactosidase was labelled with 1 mM fluorescein 5-carbamoylmethylthiopropanoic N-hydroxysuccinimidyl ester for 1 and 3 min. The samples were separated by capillary electrophoresis and peak areas compared to that of labelled BSA for the purpose of quantification of the concentration of attached label. Enzyme concentration in the samples was determined by single molecule counting. The average number of labels attached to each molecule of enzyme was found to be 3.1 and 4.5 when labelled for 1 and 3 min respectively. The distribution of single enzyme molecule electrophoretic mobilities for the unlabelled enzyme and that labelled for 1 and 3 min were measured using capillary electrophoresis. The average mobilities were found determined to be -(1.99 ± 0.13) x10-8 m2V-1s-1 (N=39), -(2.16 ± 0.19) x10-8 m2V-1s-1 (N=46), and –(2.18 ± 0.21) x10-8 m2V-1s-1 (N=39) respectively. A protein electrophoresis model was applied and predicted that the differences in average mobilities could be explained through relatively minor changes in overall charge, Stokes radius, and shape. This difference was similar to the range in mobilities observed in the unlabelled protein. This is consistent with the electrophoretic heterogeneity of the unmodified enzyme being caused by relatively small differences in charge, size, and shape of the individual molecules in the population.
{"title":"Effect of Chemical Modification on the Distribution of Electrophoretic Mobilities of Individual Molecules of E. coli β-Galactosidase","authors":"Brynne K Riehl, Allyster Klassen, Sumaiya Abas, Winner Pathak, Doug Craig","doi":"10.1139/cjc-2024-0039","DOIUrl":"https://doi.org/10.1139/cjc-2024-0039","url":null,"abstract":"Escherichia coli β-galactosidase was labelled with 1 mM fluorescein 5-carbamoylmethylthiopropanoic N-hydroxysuccinimidyl ester for 1 and 3 min. The samples were separated by capillary electrophoresis and peak areas compared to that of labelled BSA for the purpose of quantification of the concentration of attached label. Enzyme concentration in the samples was determined by single molecule counting. The average number of labels attached to each molecule of enzyme was found to be 3.1 and 4.5 when labelled for 1 and 3 min respectively. The distribution of single enzyme molecule electrophoretic mobilities for the unlabelled enzyme and that labelled for 1 and 3 min were measured using capillary electrophoresis. The average mobilities were found determined to be -(1.99 ± 0.13) x10-8 m2V-1s-1 (N=39), -(2.16 ± 0.19) x10-8 m2V-1s-1 (N=46), and –(2.18 ± 0.21) x10-8 m2V-1s-1 (N=39) respectively. A protein electrophoresis model was applied and predicted that the differences in average mobilities could be explained through relatively minor changes in overall charge, Stokes radius, and shape. This difference was similar to the range in mobilities observed in the unlabelled protein. This is consistent with the electrophoretic heterogeneity of the unmodified enzyme being caused by relatively small differences in charge, size, and shape of the individual molecules in the population.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141926647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The chemistry of platinum(II) and platinum(IV) with the ligands 3,4,5-tris(2-pyridyl)-4-H-1,2,4-triazole, L1, and 3,5-di(2-pyridyl)-4-(4-pyridyl)-4-H-1,2,4-triazole, L2, is described. The ligand L1 forms platinum(II) complexes [PtXY(κ2-N,N’-L1)] (X,Y = Cl,Cl; Cl,Me; Me,Me) by chelation while ligand L2 forms either analogous chelate complexes [PtXY(κ2-N,N’-L2)] (X,Y = Cl,Me; Me,Me) or acts as a monodentate ligand in forming trans-[PtCl2(SMe2)(κ1-N-L2)], in which only the 4-pyridyl group is coordinated. The electron-rich dimethylplatinum(II) complexes undergo oxidative addition reactions with methyl iodide to give [PtIMe3(κ2-N,N’-L1)], or with dichloromethane to give [PtClMe2(CH2Cl)(κ2-N,N’-L1)] or [PtClMe2(CH2Cl)(κ2-N,N’-L2)], each of which is formed as a mixture of three isomers. Structure determinations of several of these complexes are reported.
{"title":"Platinum complexes with pyridyl derivatives of 1,2,4-triazole","authors":"Anwar Abo-Amer, Paul D. Boyle, R. Puddephatt","doi":"10.1139/cjc-2024-0125","DOIUrl":"https://doi.org/10.1139/cjc-2024-0125","url":null,"abstract":"The chemistry of platinum(II) and platinum(IV) with the ligands 3,4,5-tris(2-pyridyl)-4-H-1,2,4-triazole, L1, and 3,5-di(2-pyridyl)-4-(4-pyridyl)-4-H-1,2,4-triazole, L2, is described. The ligand L1 forms platinum(II) complexes [PtXY(κ2-N,N’-L1)] (X,Y = Cl,Cl; Cl,Me; Me,Me) by chelation while ligand L2 forms either analogous chelate complexes [PtXY(κ2-N,N’-L2)] (X,Y = Cl,Me; Me,Me) or acts as a monodentate ligand in forming trans-[PtCl2(SMe2)(κ1-N-L2)], in which only the 4-pyridyl group is coordinated. The electron-rich dimethylplatinum(II) complexes undergo oxidative addition reactions with methyl iodide to give [PtIMe3(κ2-N,N’-L1)], or with dichloromethane to give [PtClMe2(CH2Cl)(κ2-N,N’-L1)] or [PtClMe2(CH2Cl)(κ2-N,N’-L2)], each of which is formed as a mixture of three isomers. Structure determinations of several of these complexes are reported.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141830702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fires originating from coal spontaneous combustion within coalfields result not only in substantial coal resource depletion but also producing residual low-activity pyrolysis coal chars exhibiting varying degrees of oxidation. These chars develop progressively through successive heat penetration at the fire front and post-fire extinguishment phases. This paper focuses on the alkaline earth metal-activated catalytic gasification of residual oxidized coal in fire zones, constructs a carbon-based model of oxidized coal in fire zones. The results show that the reaction active sites of the oxidized coal carbon matrix model are mainly concentrated on the carbon atoms at the end of the aromatic ring. During catalytic gasification, the calcium-based catalyst engages with these active sites, forming a preliminary catalyst. The transformation of oxidized coal into CO primarily occurs through two distinct routes. Calcium attaches to the surface of the oxidized coal's carbon-based structure, establishing active sites. Acting as a facilitator, it aids the movement of CO2 to the carbon-based surface, leading to its further breakdown into CO. The catalytic species containing calcium persistently amalgamates with active sites on coal coke surface, fostering the release of additional CO. Moreover, these catalytic species with calcium also bind CO2 and unite with active coal coke sites, generating carbon-oxygen complexes on the surface. These complexes are thermally unstable and decompose, yielding CO and initiating the formation of fresh active sites on the coal coke surface. Consequently, they interact further with calcium-based catalytic species, culminating in the creation of catalyst precursors, which drive a recurrent catalytic reaction process.
{"title":"Reaction Mechanism of Catalytic Gasification by Calcium-Based Catalysts and Oxidized Coal Residues in Coalfield Fire Zones","authors":"Liangzhou Chen, Wei Lu, Xuyao Qi","doi":"10.1139/cjc-2024-0087","DOIUrl":"https://doi.org/10.1139/cjc-2024-0087","url":null,"abstract":"Fires originating from coal spontaneous combustion within coalfields result not only in substantial coal resource depletion but also producing residual low-activity pyrolysis coal chars exhibiting varying degrees of oxidation. These chars develop progressively through successive heat penetration at the fire front and post-fire extinguishment phases. This paper focuses on the alkaline earth metal-activated catalytic gasification of residual oxidized coal in fire zones, constructs a carbon-based model of oxidized coal in fire zones. The results show that the reaction active sites of the oxidized coal carbon matrix model are mainly concentrated on the carbon atoms at the end of the aromatic ring. During catalytic gasification, the calcium-based catalyst engages with these active sites, forming a preliminary catalyst. The transformation of oxidized coal into CO primarily occurs through two distinct routes. Calcium attaches to the surface of the oxidized coal's carbon-based structure, establishing active sites. Acting as a facilitator, it aids the movement of CO2 to the carbon-based surface, leading to its further breakdown into CO. The catalytic species containing calcium persistently amalgamates with active sites on coal coke surface, fostering the release of additional CO. Moreover, these catalytic species with calcium also bind CO2 and unite with active coal coke sites, generating carbon-oxygen complexes on the surface. These complexes are thermally unstable and decompose, yielding CO and initiating the formation of fresh active sites on the coal coke surface. Consequently, they interact further with calcium-based catalytic species, culminating in the creation of catalyst precursors, which drive a recurrent catalytic reaction process.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141652123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abigail J. Van Riesen, Keenan T Regan, Baylie Kalnitsky, Aron A. Shoara, S. Slavkovic, Zachary R. Churcher, Philip E Johnson, Giammarco Nebbioso, Sergey Krylov, R. Manderville
Activatable fluorescent probes with turn-on emission in response to a biological target can reduce the background signal and improve the detection limit needed for biosensor and bioimaging resolution. Turn-on probes with dual emission (ratiometric probes) have further advantages, as they have self-calibration ability for more reliable detection. Herein we demonstrate the tunability of the phenolic hemicyanine (HC) scaffold for both DNA biosensing and bioimaging applications using the quinine-binding DNA aptamer (MN4) as a host-guest biosensor platform and live ovarian cancer cells for nuclear imaging. The DNA aptamer MN4 contains a three-way junction (3WJ) consisting of a hydrophobic branch point connecting three double-stranded stems. Phenolic HCs bearing electron-withdrawing halogen substituents (FPhOBtz and Cl2PhOBTz) bind to the 3WJ of MN4 as the phenolate with strong turn-on emission. Subsequent displacement of the phenolate by the quinine target causes a turn-off emission response. In contrast, the parent phenolic HC (PhOBtz) and those bearing electron-donating groups (Me2PhOBtz and (MeO)2PhOBtz) exhibit dual (phenol and phenolate) fluorescence upon MN4 binding. Phenol excitation generates phenolate emission by an excited-state proton transfer (ESPT) process with DNA components serving as the proton acceptor. Quinine displacement of PhOBtz from the 3WJ of MN4 affords a turn-on ratiometric response with preferential light-up of phenol emission. The ability of the phenolic HCs to serve as cellular nuclear stains further highlights the tunability of the phenolic HC probes with the Cl2PhOBtz analog displaying superior staining ability. The simplicity and tunability of phenolic HCs make them attractive fluorescent probes for DNA sensing and bioimaging applications.
{"title":"Tuning Phenolic Hemicyanines for Ratiometric DNA Sensing and Live Cell Nuclear Bioimaging Applications","authors":"Abigail J. Van Riesen, Keenan T Regan, Baylie Kalnitsky, Aron A. Shoara, S. Slavkovic, Zachary R. Churcher, Philip E Johnson, Giammarco Nebbioso, Sergey Krylov, R. Manderville","doi":"10.1139/cjc-2024-0014","DOIUrl":"https://doi.org/10.1139/cjc-2024-0014","url":null,"abstract":"Activatable fluorescent probes with turn-on emission in response to a biological target can reduce the background signal and improve the detection limit needed for biosensor and bioimaging resolution. Turn-on probes with dual emission (ratiometric probes) have further advantages, as they have self-calibration ability for more reliable detection. Herein we demonstrate the tunability of the phenolic hemicyanine (HC) scaffold for both DNA biosensing and bioimaging applications using the quinine-binding DNA aptamer (MN4) as a host-guest biosensor platform and live ovarian cancer cells for nuclear imaging. The DNA aptamer MN4 contains a three-way junction (3WJ) consisting of a hydrophobic branch point connecting three double-stranded stems. Phenolic HCs bearing electron-withdrawing halogen substituents (FPhOBtz and Cl2PhOBTz) bind to the 3WJ of MN4 as the phenolate with strong turn-on emission. Subsequent displacement of the phenolate by the quinine target causes a turn-off emission response. In contrast, the parent phenolic HC (PhOBtz) and those bearing electron-donating groups (Me2PhOBtz and (MeO)2PhOBtz) exhibit dual (phenol and phenolate) fluorescence upon MN4 binding. Phenol excitation generates phenolate emission by an excited-state proton transfer (ESPT) process with DNA components serving as the proton acceptor. Quinine displacement of PhOBtz from the 3WJ of MN4 affords a turn-on ratiometric response with preferential light-up of phenol emission. The ability of the phenolic HCs to serve as cellular nuclear stains further highlights the tunability of the phenolic HC probes with the Cl2PhOBtz analog displaying superior staining ability. The simplicity and tunability of phenolic HCs make them attractive fluorescent probes for DNA sensing and bioimaging applications.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141656100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The electrochemical reduction of a series of nitro-substituted benzenesulfonyl chlorides is investigated. The results of the electrochemical study are analysed with the assistance of theoretical calculations. The study shows that the electron transfer mechanism depends on the position of the nitro substituent on the phenyl ring. The 3-nitrobenzenesulfonyl chloride follows a stepwise mechanism where the reduction leads to an intermediate radical anion. For the 4-nitrobenzenesulfonyl chloride, 2-nitrobenzenesulfonyl chloride, and 2,4-nitrobenzenesulfonyl chloride, the reduction follows a “sticky” dissociative mechanism, where the electron transfer and S-Cl bond cleavage are concerted. The dissociation products (arylsulfinyl radical and chloride anion) show strong interactions. The difference in behaviour is associated with the overlap of the π* orbital and the S-Cl σ* orbital for the latter three compounds. The through resonance stability of the arylsulfinyl radicals for the para and ortho nitro-substituted compounds facilitates the dissociation of the reduced structures. Upon reduction, the 3-nitrobenzenesulfonyl chloride and 4-nitrobenzenesulfonyl chloride, also produce the corresponding diaryl disulfones, which are easier to reduce that the parent molecules and hence induce an interesting autocatalytic mechanism. Such mechanism, which depends on the concentration and the scan rate, does not take place with for the 2-nitrobenzenesulfonyl chloride and 2,4-dinitrobenzenesulfonyl chloride due to the sterical hindrance of the nitro substituent at the ortho position, as it prevents formation of the disulfones.
{"title":"Effect of the Position of the Substituent in the Electrochemical Reduction of Nitro-Substituted Benzenesulfonyl Chlorides","authors":"M. Saley, Emad M. Hamed, Abdelaziz Houmam","doi":"10.1139/cjc-2024-0052","DOIUrl":"https://doi.org/10.1139/cjc-2024-0052","url":null,"abstract":"The electrochemical reduction of a series of nitro-substituted benzenesulfonyl chlorides is investigated. The results of the electrochemical study are analysed with the assistance of theoretical calculations. The study shows that the electron transfer mechanism depends on the position of the nitro substituent on the phenyl ring. The 3-nitrobenzenesulfonyl chloride follows a stepwise mechanism where the reduction leads to an intermediate radical anion. For the 4-nitrobenzenesulfonyl chloride, 2-nitrobenzenesulfonyl chloride, and 2,4-nitrobenzenesulfonyl chloride, the reduction follows a “sticky” dissociative mechanism, where the electron transfer and S-Cl bond cleavage are concerted. The dissociation products (arylsulfinyl radical and chloride anion) show strong interactions. The difference in behaviour is associated with the overlap of the π* orbital and the S-Cl σ* orbital for the latter three compounds. The through resonance stability of the arylsulfinyl radicals for the para and ortho nitro-substituted compounds facilitates the dissociation of the reduced structures. Upon reduction, the 3-nitrobenzenesulfonyl chloride and 4-nitrobenzenesulfonyl chloride, also produce the corresponding diaryl disulfones, which are easier to reduce that the parent molecules and hence induce an interesting autocatalytic mechanism. Such mechanism, which depends on the concentration and the scan rate, does not take place with for the 2-nitrobenzenesulfonyl chloride and 2,4-dinitrobenzenesulfonyl chloride due to the sterical hindrance of the nitro substituent at the ortho position, as it prevents formation of the disulfones.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141657416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Picromerite K2Mg(SO4)2•6H2O (also known as schoenite, schönite, or sulfate of potash) formed from alkaline lakes by evaporation is an increasingly important chlorine-free fertilizer and has been used to produce other organic fertilizers such as arcanite K2SO4 and boussingaultite (NH4)2Mg(SO4)2•6H2O. Picromerite and boussingaultite, two Tutton’s salts, are also common secondary solid phases in diverse types of mine tailings and play important roles in controlling the mobility and bioavailability of various heavy metal(loid)s, including arsenic. In this study, picromerite crystals containing 64 ppm As have been synthesized at ambient conditions from aqueous solutions by slow evaporation. Arsenic K-edge X-ray absorption near-edge-structure (XANES) and extended X-ray absorption fine structure (EXAFS) data show that the dominant oxidation state is +5 and that As5+ occupies the S site in picromerite. Single-crystal and powder electron paramagnetic resonance (EPR) spectra of gamma-ray-irradiated picromerite reveal three arsenic-associated oxyradicals: AsO42−, AsO32−, and AsO22−. The orientations of the principal 75As hyperfine directions of the AsO32− and AsO22− radicals match the bonding directions of the SO42− groups in the picromerite structure, further supporting substitutions of their respective diamagnetic precursors AsO43- and AsO33- for the sulfate group. These AsO42−, AsO32−, and AsO22− radicals in picromerite are similar but not identical to their counterparts in boussingaultite and gypsum, suggesting that sulfate minerals are capable of sequestrating both arsenate and arsenite, with important implications for understanding the fate and bioavailability of arsenic associated with agricultural applications of organic fertilizers.
从碱性湖泊中蒸发形成的钾长石 K2Mg(SO4)2-6H2O（又称钾长石、钾长石或硫酸盐）是一种日益重要的无氯肥料，并已被用于生产其他有机肥料，如钾长石 K2SO4 和钾长石 (NH4)2Mg(SO4)2-6H2O。黝帘石和布辛格芒硝这两种塔顿盐也是各种类型矿山尾矿中常见的次生固相，在控制包括砷在内的各种重金属的流动性和生物利用率方面发挥着重要作用。本研究在环境条件下，通过缓慢蒸发从水溶液中合成了含 64ppm As 的皮罗莫来石晶体。砷 K 边 X 射线吸收近边结构（XANES）和扩展 X 射线吸收精细结构（EXAFS）数据表明，主要氧化态为 +5，As5+占据了皮罗莫来石中的 S 位。伽马射线辐照过的皮绿泥石的单晶和粉末电子顺磁共振（EPR）光谱显示出三种砷相关的氧化态：AsO42-、AsO32- 和 AsO22-。AsO32- 和 AsO22- 自由基的主要 75As 超正弦方向与皮铬铁矿结构中 SO42- 基团的成键方向一致，这进一步支持了它们各自的二磁性前体 AsO43- 和 AsO33- 对硫酸基团的取代。辉绿岩中的这些 AsO42-、AsO32- 和 AsO22- 自由基与它们在布辛格雷石和石膏中的对应物相似，但不完全相同，这表明硫酸盐矿物能够螯合砷酸盐和亚砷酸盐，这对了解与农业施用有机肥相关的砷的归宿和生物利用率具有重要意义。
{"title":"Arsenic speciation in picromerite K2Mg(SO4)2•6H2O: Electron paramagnetic resonance and synchrotron X-ray absorption spectroscopic characterizations and implications for organic fertilizers","authors":"Jinru Lin, Ning Chen, Yuanming Pan","doi":"10.1139/cjc-2024-0044","DOIUrl":"https://doi.org/10.1139/cjc-2024-0044","url":null,"abstract":"Picromerite K2Mg(SO4)2•6H2O (also known as schoenite, schönite, or sulfate of potash) formed from alkaline lakes by evaporation is an increasingly important chlorine-free fertilizer and has been used to produce other organic fertilizers such as arcanite K2SO4 and boussingaultite (NH4)2Mg(SO4)2•6H2O. Picromerite and boussingaultite, two Tutton’s salts, are also common secondary solid phases in diverse types of mine tailings and play important roles in controlling the mobility and bioavailability of various heavy metal(loid)s, including arsenic. In this study, picromerite crystals containing 64 ppm As have been synthesized at ambient conditions from aqueous solutions by slow evaporation. Arsenic K-edge X-ray absorption near-edge-structure (XANES) and extended X-ray absorption fine structure (EXAFS) data show that the dominant oxidation state is +5 and that As5+ occupies the S site in picromerite. Single-crystal and powder electron paramagnetic resonance (EPR) spectra of gamma-ray-irradiated picromerite reveal three arsenic-associated oxyradicals: AsO42−, AsO32−, and AsO22−. The orientations of the principal 75As hyperfine directions of the AsO32− and AsO22− radicals match the bonding directions of the SO42− groups in the picromerite structure, further supporting substitutions of their respective diamagnetic precursors AsO43- and AsO33- for the sulfate group. These AsO42−, AsO32−, and AsO22− radicals in picromerite are similar but not identical to their counterparts in boussingaultite and gypsum, suggesting that sulfate minerals are capable of sequestrating both arsenate and arsenite, with important implications for understanding the fate and bioavailability of arsenic associated with agricultural applications of organic fertilizers.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141665406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuanyuan Zhang, Mengyi Ba, Wen Li, Yanli Song, Xiang Xu, Haixin Liu, Wenxuan Zhao, T. Sun, Zhiqiang Cai
Herein, we synthesized and used a novel pillar[5]arene with two functionalizable rims (AP5A-C10-OAc) as stationary phase in gas chromatography (GC). The AP5A-C10-OAc column (0.25 mm, i.d.) showed a high column efficiency of 4107 plates/m and medium polarity. The AP5A-C10-OAc stationary phase possesses unique amphiphilic structure, including a π-electron rich cavity and two functionalized arms composed of five nonpolar alkyl chains and five polar ester chains, and showed good separation performance for diverse types of analytes and isomers (apolar/polar, aliphatic/aromatic). Particularly, the AP5A-C10-OAc phase showed high selectivity for the challenging isomers of chloronitrobenzenes, bromonitrobenzenes, benzenediols, and iodoanilines with distinct advantages if compared with the commercial polysiloxane column.
{"title":"Two different rims functionalized pillar[5]arene stationary phase for capillary gas chromatography","authors":"Yuanyuan Zhang, Mengyi Ba, Wen Li, Yanli Song, Xiang Xu, Haixin Liu, Wenxuan Zhao, T. Sun, Zhiqiang Cai","doi":"10.1139/cjc-2024-0066","DOIUrl":"https://doi.org/10.1139/cjc-2024-0066","url":null,"abstract":"Herein, we synthesized and used a novel pillar[5]arene with two functionalizable rims (AP5A-C10-OAc) as stationary phase in gas chromatography (GC). The AP5A-C10-OAc column (0.25 mm, i.d.) showed a high column efficiency of 4107 plates/m and medium polarity. The AP5A-C10-OAc stationary phase possesses unique amphiphilic structure, including a π-electron rich cavity and two functionalized arms composed of five nonpolar alkyl chains and five polar ester chains, and showed good separation performance for diverse types of analytes and isomers (apolar/polar, aliphatic/aromatic). Particularly, the AP5A-C10-OAc phase showed high selectivity for the challenging isomers of chloronitrobenzenes, bromonitrobenzenes, benzenediols, and iodoanilines with distinct advantages if compared with the commercial polysiloxane column.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141680242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Monitoring organic pollutants in rainwater is important to understand relations between air pollutants and water safety. Non-targeted liquid chromatography–mass spectrometry (LC–MS) is a powerful tool but because of big differences of pollutants in polarity, ionization efficiency, and low concentrations, it is challenging to detect all pollutants in a single analysis. Chemical derivatization is a widely adapted strategy to fractionate complex samples with enhanced sensitivity and selectivity. Herein, we propose the usage of dansylation as a chemical derivatization method to improve both LC retention and MS ionization of organic pollutants containing amine, hydroxyl, and carboxyl for non-targeted LC–MS analysis. We first evaluated the labeling coverage of dansylation to organic pollutants in water matrix. Using dansyl chloride (DnsCl) and dansyl hydrazine (DnsHz) to label 100 amine- and hydroxyl-containing compounds and 100 carboxyl compounds, respectively, we found DnsCl and DnsHz had over 60% labeling coverage for 8 categories of compounds. Then dansylation was applied to label the rainwater, source water, disinfected rainwater, and drinking water samples. To facilitate the annotation of dansylated compounds, we also established a web-based tool termed DansylFinder. Using DansylFinder, 3889, 5813, 6077, and 4050 tentative annotations were found in rainwater, source water, disinfected rainwater, and drinking water samples by dansylation-based non-targeted LC-HRMS analysis. Four hundred fifty four were persistently detected in all water samples, suggesting significant organic overlaps of the four water samples. In addition, two degradation pathways reported in drinking water disinfection process were also detected in disinfected rainwater, suggesting rainwater is a potential path for air pollutants to infiltrate drinking water system.
{"title":"Profiling organic pollutants in environmental water by dansylation-based non-targeted liquid chromatography-high resolution mass spectrometry analysis","authors":"Bin Chen, Lirong An, Feng Li, Yanan Tang","doi":"10.1139/cjc-2024-0013","DOIUrl":"https://doi.org/10.1139/cjc-2024-0013","url":null,"abstract":"Monitoring organic pollutants in rainwater is important to understand relations between air pollutants and water safety. Non-targeted liquid chromatography–mass spectrometry (LC–MS) is a powerful tool but because of big differences of pollutants in polarity, ionization efficiency, and low concentrations, it is challenging to detect all pollutants in a single analysis. Chemical derivatization is a widely adapted strategy to fractionate complex samples with enhanced sensitivity and selectivity. Herein, we propose the usage of dansylation as a chemical derivatization method to improve both LC retention and MS ionization of organic pollutants containing amine, hydroxyl, and carboxyl for non-targeted LC–MS analysis. We first evaluated the labeling coverage of dansylation to organic pollutants in water matrix. Using dansyl chloride (DnsCl) and dansyl hydrazine (DnsHz) to label 100 amine- and hydroxyl-containing compounds and 100 carboxyl compounds, respectively, we found DnsCl and DnsHz had over 60% labeling coverage for 8 categories of compounds. Then dansylation was applied to label the rainwater, source water, disinfected rainwater, and drinking water samples. To facilitate the annotation of dansylated compounds, we also established a web-based tool termed DansylFinder. Using DansylFinder, 3889, 5813, 6077, and 4050 tentative annotations were found in rainwater, source water, disinfected rainwater, and drinking water samples by dansylation-based non-targeted LC-HRMS analysis. Four hundred fifty four were persistently detected in all water samples, suggesting significant organic overlaps of the four water samples. In addition, two degradation pathways reported in drinking water disinfection process were also detected in disinfected rainwater, suggesting rainwater is a potential path for air pollutants to infiltrate drinking water system.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141683939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Austin Luke L. Burman, Jonathan K. Sader, Jeremy E. Wulff
A substituted bishomocubane structure colloquially known as a Thiele cage was previously observed to undergo an alkyl-extended pinacol-type rearrangement, wherein 1,2-aryl migration and ketone formation occurred together with (or at least in close succession to) opening of a strained cyclobutane bond. While there was some indication that the rearrangement reaction might proceed via a stepwise process involving a sequence of carbocation intermediates, previous studies did not uncover any direct evidence for the formation of carbocations, and did not fully explain the regio- and stereospecificity of the reaction. Here we describe the isolation and detailed characterization of a second rearrangement product formed under the pinacol reaction conditions, the existence of which implicates the formation of discrete carbocation intermediates along the reaction pathway. Observation of this new product also finally explains the fate of any Thiele cage material that is converted to a carbocation, but which is not geometrically predisposed to react through a facile 1,2-aryl migration. As such, our findings resolve previous questions surrounding the origin of regio- and stereospecificity in the alkyl-extended pinacol rearrangement.
{"title":"Structural Determination of a Carbocation-Derived Rearrangement Product Observed During Thiele Cage Opening: Insight Into the Mechanism of an Alkyl-Extended Pinacol Reaction","authors":"Austin Luke L. Burman, Jonathan K. Sader, Jeremy E. Wulff","doi":"10.1139/cjc-2024-0025","DOIUrl":"https://doi.org/10.1139/cjc-2024-0025","url":null,"abstract":"A substituted bishomocubane structure colloquially known as a Thiele cage was previously observed to undergo an alkyl-extended pinacol-type rearrangement, wherein 1,2-aryl migration and ketone formation occurred together with (or at least in close succession to) opening of a strained cyclobutane bond. While there was some indication that the rearrangement reaction might proceed via a stepwise process involving a sequence of carbocation intermediates, previous studies did not uncover any direct evidence for the formation of carbocations, and did not fully explain the regio- and stereospecificity of the reaction. Here we describe the isolation and detailed characterization of a second rearrangement product formed under the pinacol reaction conditions, the existence of which implicates the formation of discrete carbocation intermediates along the reaction pathway. Observation of this new product also finally explains the fate of any Thiele cage material that is converted to a carbocation, but which is not geometrically predisposed to react through a facile 1,2-aryl migration. As such, our findings resolve previous questions surrounding the origin of regio- and stereospecificity in the alkyl-extended pinacol rearrangement.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141336081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zakariya M Abidullah, Heliben V Patel, J. A. Broome, Eric A. C. Bushnell
Fossil fuels are rapidly being depleted and releasing great amounts of greenhouse gases, causing harmful effects to the environment. Renewable energy such as solar energy is an alternative option instead of using fossil fuels. However, storing the energy harvested as H2 by the electrolysis of H2O requires an effective, cheap catalyst to be practical. Thus, Ni catalysts are a valid option to produce hydrogen gas. In this study, the thermodynamics, and kinetics of ET for the electrocatalytic production of H2 by analogous Ni-bis(dithiolene), Ni-bis(diselenolene), Ni-bis(ditellurolene) complexes were studied using DFT. Thermodynamically, it was found that all three catalysts catalyze the formation of H2 with similar energetic cost. However, for release of H2 the catalysts must be doubly protonated and triply reduced. While the first two reductions occur with low Gibbs activation energies the third reduction does not. Therefore, if a third reduction is required for electrocatalytic H2 production a large overpotential would be expected from our predictions.
{"title":"A Computational Investigation into the Electron-Transfer Kinetics and Thermodynamics of Hydrogen gas production by Ni(S2C2H2)2, Ni(Se2C2H2)2, and Ni(Te2C2H2) complexes","authors":"Zakariya M Abidullah, Heliben V Patel, J. A. Broome, Eric A. C. Bushnell","doi":"10.1139/cjc-2023-0147","DOIUrl":"https://doi.org/10.1139/cjc-2023-0147","url":null,"abstract":"Fossil fuels are rapidly being depleted and releasing great amounts of greenhouse gases, causing harmful effects to the environment. Renewable energy such as solar energy is an alternative option instead of using fossil fuels. However, storing the energy harvested as H2 by the electrolysis of H2O requires an effective, cheap catalyst to be practical. Thus, Ni catalysts are a valid option to produce hydrogen gas. In this study, the thermodynamics, and kinetics of ET for the electrocatalytic production of H2 by analogous Ni-bis(dithiolene), Ni-bis(diselenolene), Ni-bis(ditellurolene) complexes were studied using DFT. Thermodynamically, it was found that all three catalysts catalyze the formation of H2 with similar energetic cost. However, for release of H2 the catalysts must be doubly protonated and triply reduced. While the first two reductions occur with low Gibbs activation energies the third reduction does not. Therefore, if a third reduction is required for electrocatalytic H2 production a large overpotential would be expected from our predictions.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141368557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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