Pub Date : 2022-08-15DOI: 10.3390/compounds2030016
M. Coltelli, S. Coiai
Synthetic polymers and biodegradable and biobased polymers are currently the largest class of materials studied and used for various applications due to their unique and peculiar properties [...]
{"title":"Polymeric Substrates Modification with Biobased Functional Compounds","authors":"M. Coltelli, S. Coiai","doi":"10.3390/compounds2030016","DOIUrl":"https://doi.org/10.3390/compounds2030016","url":null,"abstract":"Synthetic polymers and biodegradable and biobased polymers are currently the largest class of materials studied and used for various applications due to their unique and peculiar properties [...]","PeriodicalId":10621,"journal":{"name":"Compounds","volume":"108 1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89708993","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 : 2022-08-02DOI: 10.3390/compounds2030015
J. Mejuto, Antonio Cid-Samamed
Since the second half of the last century, the science of colloids has undergone a true revolution, from being little more than a collection of qualitative observations of the macroscopic behavior of some complex systems to becoming a discipline with substantial theoretical foundations [...]
{"title":"Chemical Reactivity in Microheterogeneous Media","authors":"J. Mejuto, Antonio Cid-Samamed","doi":"10.3390/compounds2030015","DOIUrl":"https://doi.org/10.3390/compounds2030015","url":null,"abstract":"Since the second half of the last century, the science of colloids has undergone a true revolution, from being little more than a collection of qualitative observations of the macroscopic behavior of some complex systems to becoming a discipline with substantial theoretical foundations [...]","PeriodicalId":10621,"journal":{"name":"Compounds","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77825179","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 : 2022-07-15DOI: 10.3390/compounds2030014
M. Martino
In the field of industrial chemistry, catalysts play a fundamental role in determining the ability of chemical production processes to reach and improve productivity targets [...]
在工业化学领域，催化剂在决定化学生产过程达到和提高生产率目标的能力方面起着根本作用。
{"title":"Structured Supports and Catalysts: Design, Preparation, and Applications","authors":"M. Martino","doi":"10.3390/compounds2030014","DOIUrl":"https://doi.org/10.3390/compounds2030014","url":null,"abstract":"In the field of industrial chemistry, catalysts play a fundamental role in determining the ability of chemical production processes to reach and improve productivity targets [...]","PeriodicalId":10621,"journal":{"name":"Compounds","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91535125","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 : 2022-06-13DOI: 10.3390/compounds2020012
A. Rebiai, B. B. Seghir, H. Hemmami, S. Zeghoud, I. B. Amor, I. Kouadri, M. Messaoudi, Ardalan Pasdaran, G. Caruso, Somesh Sharma, M. Atanassova, P. Pohl
Since ancient times, herbal medicines (HM) have played a vital role in worldwide healthcare systems. It is therefore critical that a thorough evaluation of the quality and control of its complicated chemical makeup be conducted, in order to ensure its efficacy and safety. The notion of HM chemical prints, which aim to acquire a full characterization of compound chemical matrices, has become one of the most persuasive techniques for HM quality evaluation during the last few decades. The link between NMR and chemometrics is discussed in this article. The chemometric latent variable technique has been shown to be extremely valuable in inductive studies of biological systems as well as in solving industrial challenges. The results of unsupervised data exploration utilizing main component analysis as well as the multivariate curve resolution, were various. On the other hand, many contemporary NMR applications in metabolomics and quality control are based on supervised regression or classification analyses.
{"title":"Quality Assessment of Medicinal Plants via Chemometric Exploration of Quantitative NMR Data: A Review","authors":"A. Rebiai, B. B. Seghir, H. Hemmami, S. Zeghoud, I. B. Amor, I. Kouadri, M. Messaoudi, Ardalan Pasdaran, G. Caruso, Somesh Sharma, M. Atanassova, P. Pohl","doi":"10.3390/compounds2020012","DOIUrl":"https://doi.org/10.3390/compounds2020012","url":null,"abstract":"Since ancient times, herbal medicines (HM) have played a vital role in worldwide healthcare systems. It is therefore critical that a thorough evaluation of the quality and control of its complicated chemical makeup be conducted, in order to ensure its efficacy and safety. The notion of HM chemical prints, which aim to acquire a full characterization of compound chemical matrices, has become one of the most persuasive techniques for HM quality evaluation during the last few decades. The link between NMR and chemometrics is discussed in this article. The chemometric latent variable technique has been shown to be extremely valuable in inductive studies of biological systems as well as in solving industrial challenges. The results of unsupervised data exploration utilizing main component analysis as well as the multivariate curve resolution, were various. On the other hand, many contemporary NMR applications in metabolomics and quality control are based on supervised regression or classification analyses.","PeriodicalId":10621,"journal":{"name":"Compounds","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86230683","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 : 2022-05-23DOI: 10.3390/compounds2020011
G. Pelosi, S. Pinelli, F. Bisceglie
Some ten million cancer deaths occurred in 2020, highlighting the fact that the search for new anticancer drugs remains extremely topical. In the search for new coordination compounds with relevant biological properties, the choice of a metal ion is important for the design of the complex. In this regard, copper plays a peculiar role, thanks to its distinct properties. Thiosemicarbazones are, analogously, a unique class of ligands because they are easily modifiable, and therefore, extremely versatile in terms of modulating molecular properties. In this work, we synthesized and characterized, by means of X-ray diffraction, four new naphthaldehyde and anthraldehyde thiosemicarbazone derivatives and their copper complexes to be used in interaction studies with biological systems. The objective was to evaluate the antileukemic activity of these compounds. Reactions of these ligands with Cu(II) salts produced unexpected oxidation products and the isolation of Cu(I) metal complexes. One ligand and its related Cu(I) complex, which is stable in physiological conditions, were subjected to in vitro biological tests (UV-Vis and CD titration). An important interaction with DNA and an affinity toward BSA were observed in FT-IR experiments. Preliminary in vitro biological tests against a histiocytic lymphoma cell line revealed an interestingly low IC50 value, i.e., 5.46 µM, for the Cu(I) complex.
{"title":"DNA and BSA Interaction Studies and Antileukemic Evaluation of Polyaromatic Thiosemicarbazones and Their Copper Complexes","authors":"G. Pelosi, S. Pinelli, F. Bisceglie","doi":"10.3390/compounds2020011","DOIUrl":"https://doi.org/10.3390/compounds2020011","url":null,"abstract":"Some ten million cancer deaths occurred in 2020, highlighting the fact that the search for new anticancer drugs remains extremely topical. In the search for new coordination compounds with relevant biological properties, the choice of a metal ion is important for the design of the complex. In this regard, copper plays a peculiar role, thanks to its distinct properties. Thiosemicarbazones are, analogously, a unique class of ligands because they are easily modifiable, and therefore, extremely versatile in terms of modulating molecular properties. In this work, we synthesized and characterized, by means of X-ray diffraction, four new naphthaldehyde and anthraldehyde thiosemicarbazone derivatives and their copper complexes to be used in interaction studies with biological systems. The objective was to evaluate the antileukemic activity of these compounds. Reactions of these ligands with Cu(II) salts produced unexpected oxidation products and the isolation of Cu(I) metal complexes. One ligand and its related Cu(I) complex, which is stable in physiological conditions, were subjected to in vitro biological tests (UV-Vis and CD titration). An important interaction with DNA and an affinity toward BSA were observed in FT-IR experiments. Preliminary in vitro biological tests against a histiocytic lymphoma cell line revealed an interestingly low IC50 value, i.e., 5.46 µM, for the Cu(I) complex.","PeriodicalId":10621,"journal":{"name":"Compounds","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84742609","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 : 2022-04-12DOI: 10.3390/compounds2020009
Marisabel Mecca, R. Racioppi, V. Romano, L. Viggiani, R. Lorenz, M. D’Auria
HS-SPME-GC–MS analysis of the scent of Dactylorhiza viridis revealed the presence of verbenone (28.86%), caryophyllene (25.67%), β-terpineol (9.48%), and δ-cadinene (6.94%). In the scent of Dactylorhiza romana β-ocimene (18.69%), pentadecane (18.40%), α-farnesene (14.65%), and isopropyl 14-methylpentadecanoate (14.32%) were found. Dactylorhiza incarnata contained tetradecane (11.07%), pentadecane (28.40%), hexadecane (19.53%), heptadecane (17.33%), and α-cubenene (11.48%). Analysis of Dactylorhiza saccifera showed the presence of caryophyllene (17.38%), pentadecane (6.43%), hexadecane (6.13%), and heptadecane (5.08%). Finally, the aroma components found in Dactylorhiza sambucina were caryophyllene (12.90%), β-sesquiphellandrene (32.16%), 4,5-di-epi-aristolochene (10.18%).
{"title":"Volatile Organic Compounds in Dactylorhiza Species","authors":"Marisabel Mecca, R. Racioppi, V. Romano, L. Viggiani, R. Lorenz, M. D’Auria","doi":"10.3390/compounds2020009","DOIUrl":"https://doi.org/10.3390/compounds2020009","url":null,"abstract":"HS-SPME-GC–MS analysis of the scent of Dactylorhiza viridis revealed the presence of verbenone (28.86%), caryophyllene (25.67%), β-terpineol (9.48%), and δ-cadinene (6.94%). In the scent of Dactylorhiza romana β-ocimene (18.69%), pentadecane (18.40%), α-farnesene (14.65%), and isopropyl 14-methylpentadecanoate (14.32%) were found. Dactylorhiza incarnata contained tetradecane (11.07%), pentadecane (28.40%), hexadecane (19.53%), heptadecane (17.33%), and α-cubenene (11.48%). Analysis of Dactylorhiza saccifera showed the presence of caryophyllene (17.38%), pentadecane (6.43%), hexadecane (6.13%), and heptadecane (5.08%). Finally, the aroma components found in Dactylorhiza sambucina were caryophyllene (12.90%), β-sesquiphellandrene (32.16%), 4,5-di-epi-aristolochene (10.18%).","PeriodicalId":10621,"journal":{"name":"Compounds","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74855944","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 : 2022-03-29DOI: 10.3390/compounds2020008
Micael Paulino, M. M. Pereira, N. Basílio
Flavylium/Chalcone-based molecular switches comprise features such as pH-gated photochromism and fluorescence properties that make them attractive for many applications, ranging from stimuli-responsive materials to photopharmacology. However, in contrast to other common photoswitches, the application of flavylium compounds in these areas remains largely unexplored. Among other possible reasons, this may be due to the lack of general strategies to attach these molecules to substrates such as polymers, nanoparticles, biomolecules, or surfaces. In this work, we have shown that a copper (I) catalyzed azide-alkyne cycloaddition (CuAAC) can be employed to obtain a chalcone conjugate. We used an isosorbide carbohydrate to demonstrate this strategy and investigated the photochemical properties of the chalcone-isosorbide conjugate. The obtained results show that the photochemical properties of this new compound are similar to other equivalent flavylium/chalcone photoswitches, confirming the feasibility of the conjugation strategy.
{"title":"A Photoswitchable Chalcone-Carbohydrate Conjugate Obtained by CuAAC Click Reaction","authors":"Micael Paulino, M. M. Pereira, N. Basílio","doi":"10.3390/compounds2020008","DOIUrl":"https://doi.org/10.3390/compounds2020008","url":null,"abstract":"Flavylium/Chalcone-based molecular switches comprise features such as pH-gated photochromism and fluorescence properties that make them attractive for many applications, ranging from stimuli-responsive materials to photopharmacology. However, in contrast to other common photoswitches, the application of flavylium compounds in these areas remains largely unexplored. Among other possible reasons, this may be due to the lack of general strategies to attach these molecules to substrates such as polymers, nanoparticles, biomolecules, or surfaces. In this work, we have shown that a copper (I) catalyzed azide-alkyne cycloaddition (CuAAC) can be employed to obtain a chalcone conjugate. We used an isosorbide carbohydrate to demonstrate this strategy and investigated the photochemical properties of the chalcone-isosorbide conjugate. The obtained results show that the photochemical properties of this new compound are similar to other equivalent flavylium/chalcone photoswitches, confirming the feasibility of the conjugation strategy.","PeriodicalId":10621,"journal":{"name":"Compounds","volume":"56 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86924401","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 : 2022-03-15DOI: 10.3390/compounds2010007
P. Varadwaj, Arpita Varadwaj, H. Marques, K. Yamashita
The nitrogen bond in chemical systems occurs when there is evidence of a net attractive interaction between the electrophilic region associated with a covalently or coordinately bound nitrogen atom in a molecular entity and a nucleophile in another, or the same molecular entity. It is the first member of the family of pnictogen bonds formed by the first atom of the pnictogen family, Group 15, of the periodic table, and is an inter- or intra-molecular non-covalent interaction. In this featured review, we present several illustrative crystal structures deposited in the Cambridge Structure Database (CSD) and the Inorganic Crystal Structure Databases (ICSD) to demonstrate that imide nitrogen is not the only instance where nitrogen can act as an electrophilic agent. Analysis of a set of carefully chosen illustrative crystal systems shows that a covalently bound nitrogen atom in a variety of molecular entities features a σ-hole or even a π-hole, and these have the ability to sustain attractive engagements with negative sites to form inter- and/or intramolecular interactions that drive, or assist, the formation of a crystalline phase.
{"title":"The Nitrogen Bond, or the Nitrogen-Centered Pnictogen Bond: The Covalently Bound Nitrogen Atom in Molecular Entities and Crystals as a Pnictogen Bond Donor","authors":"P. Varadwaj, Arpita Varadwaj, H. Marques, K. Yamashita","doi":"10.3390/compounds2010007","DOIUrl":"https://doi.org/10.3390/compounds2010007","url":null,"abstract":"The nitrogen bond in chemical systems occurs when there is evidence of a net attractive interaction between the electrophilic region associated with a covalently or coordinately bound nitrogen atom in a molecular entity and a nucleophile in another, or the same molecular entity. It is the first member of the family of pnictogen bonds formed by the first atom of the pnictogen family, Group 15, of the periodic table, and is an inter- or intra-molecular non-covalent interaction. In this featured review, we present several illustrative crystal structures deposited in the Cambridge Structure Database (CSD) and the Inorganic Crystal Structure Databases (ICSD) to demonstrate that imide nitrogen is not the only instance where nitrogen can act as an electrophilic agent. Analysis of a set of carefully chosen illustrative crystal systems shows that a covalently bound nitrogen atom in a variety of molecular entities features a σ-hole or even a π-hole, and these have the ability to sustain attractive engagements with negative sites to form inter- and/or intramolecular interactions that drive, or assist, the formation of a crystalline phase.","PeriodicalId":10621,"journal":{"name":"Compounds","volume":"137 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89073454","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 : 2022-03-02DOI: 10.3390/compounds2010006
Seul-Ki Kim, E. Y. Jung, Myung-Hyun Lee
The structural defect effect of impurities on silicon carbide (SiC) was studied to determine the luminescence properties with temperature-dependent photoluminescence (PL) measurements. Single 4H-SiC crystals were fabricated using three different 3C-SiC starting materials and the physical vapor transport method at a high temperature and 100 Pa in an argon atmosphere. The correlation between the impurity levels and the optical and fluorescent properties was confirmed using Raman spectroscopy, X-ray diffraction, inductively coupled plasma atomic emission spectroscopy (ICP-OES), UV-Vis-NIR spectrophotometry, and PL measurements. The PL intensity was observed in all three single 4H-SiC crystals, with the highest intensities at low temperatures. Two prominent PL emission peaks at 420 and 580 nm were observed at temperatures below 50 K. These emission peaks originated from the impurity concentration due to the incorporation of N, Al, and B in the single 4H-SiC crystals and were supported by ICP-OES. The emission peaks at 420 and 580 nm occurred due to donor–acceptor-pair recombination through the incorporated concentrations of nitrogen, boron, and aluminum in the single 4H-SiC crystals. The results of the present work provide evidence based on the low-temperature PL that the mechanism of PL emission in single 4H-SiC crystals is mainly related to the transitions due to defect concentration.
{"title":"Defect-Induced Luminescence Quenching of 4H-SiC Single Crystal Grown by PVT Method through a Control of Incorporated Impurity Concentration","authors":"Seul-Ki Kim, E. Y. Jung, Myung-Hyun Lee","doi":"10.3390/compounds2010006","DOIUrl":"https://doi.org/10.3390/compounds2010006","url":null,"abstract":"The structural defect effect of impurities on silicon carbide (SiC) was studied to determine the luminescence properties with temperature-dependent photoluminescence (PL) measurements. Single 4H-SiC crystals were fabricated using three different 3C-SiC starting materials and the physical vapor transport method at a high temperature and 100 Pa in an argon atmosphere. The correlation between the impurity levels and the optical and fluorescent properties was confirmed using Raman spectroscopy, X-ray diffraction, inductively coupled plasma atomic emission spectroscopy (ICP-OES), UV-Vis-NIR spectrophotometry, and PL measurements. The PL intensity was observed in all three single 4H-SiC crystals, with the highest intensities at low temperatures. Two prominent PL emission peaks at 420 and 580 nm were observed at temperatures below 50 K. These emission peaks originated from the impurity concentration due to the incorporation of N, Al, and B in the single 4H-SiC crystals and were supported by ICP-OES. The emission peaks at 420 and 580 nm occurred due to donor–acceptor-pair recombination through the incorporated concentrations of nitrogen, boron, and aluminum in the single 4H-SiC crystals. The results of the present work provide evidence based on the low-temperature PL that the mechanism of PL emission in single 4H-SiC crystals is mainly related to the transitions due to defect concentration.","PeriodicalId":10621,"journal":{"name":"Compounds","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90473108","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 : 2022-02-15DOI: 10.3390/compounds2010005
S. Losada-Barreiro, C. Bravo-Díaz
Aryldiazonium, ArN2+, ions decompose spontaneously through the formation of highly reactive aryl cations that undergo preferential solvation by water, showing a low selectivity towards the nucleophiles present in their solvation shell. In this work, we investigate the effects of electrolytes (NaCl, LiCl, and LiClO4) on the dediazoniation of 2-, 3-, and 4-methylbenzenediazonium ions in acidic MeOH/H2O mixtures. In the absence of electrolytes, the rates of dediazoniation, kobs, increase modestly upon increasing the MeOH content of the reaction mixture. At any solvent composition, the rate of ArN2+ loss is the same as that for product formation. The main dediazoniation products are cresols (ArOH) and methyl phenyl ethers (ArOMe). Only small amounts (less than 5%) of the reduction product toluene (ArH), which are detected at high percentages of MeOH. Quantitative yields of are obtained at any solvent composition. The addition of LiCl or NaCl ([MCl] = 0–1.5 M) to the reaction mixtures has a negligible effect on kobs but leads to the formation, in low yields (<10%), of the ArCl derivative. The addition of LiClO4 (0–1.5 M) to 20% MeOH/H2O mixtures has a negligible effect on both kobs and on the product distribution. However, at 99.5% MeOH, the addition of the same amounts of LiClO4 leads to a modest decrease in kobs but to a significant decrease in the yields of ArOMe. Results are interpreted in terms of the preferential solvation of perchlorate ions by the aryl cations, removing MeOH molecules from the solvation shell.
{"title":"Effects of Electrolytes on the Dediazoniation of Aryldiazonium Ions in Acidic MeOH/H2O Mixtures","authors":"S. Losada-Barreiro, C. Bravo-Díaz","doi":"10.3390/compounds2010005","DOIUrl":"https://doi.org/10.3390/compounds2010005","url":null,"abstract":"Aryldiazonium, ArN2+, ions decompose spontaneously through the formation of highly reactive aryl cations that undergo preferential solvation by water, showing a low selectivity towards the nucleophiles present in their solvation shell. In this work, we investigate the effects of electrolytes (NaCl, LiCl, and LiClO4) on the dediazoniation of 2-, 3-, and 4-methylbenzenediazonium ions in acidic MeOH/H2O mixtures. In the absence of electrolytes, the rates of dediazoniation, kobs, increase modestly upon increasing the MeOH content of the reaction mixture. At any solvent composition, the rate of ArN2+ loss is the same as that for product formation. The main dediazoniation products are cresols (ArOH) and methyl phenyl ethers (ArOMe). Only small amounts (less than 5%) of the reduction product toluene (ArH), which are detected at high percentages of MeOH. Quantitative yields of are obtained at any solvent composition. The addition of LiCl or NaCl ([MCl] = 0–1.5 M) to the reaction mixtures has a negligible effect on kobs but leads to the formation, in low yields (<10%), of the ArCl derivative. The addition of LiClO4 (0–1.5 M) to 20% MeOH/H2O mixtures has a negligible effect on both kobs and on the product distribution. However, at 99.5% MeOH, the addition of the same amounts of LiClO4 leads to a modest decrease in kobs but to a significant decrease in the yields of ArOMe. Results are interpreted in terms of the preferential solvation of perchlorate ions by the aryl cations, removing MeOH molecules from the solvation shell.","PeriodicalId":10621,"journal":{"name":"Compounds","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76921881","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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