The synthesis and characterization of four dumbbell‐shaped fullerene molecules connected by isoso... more The synthesis and characterization of four dumbbell‐shaped fullerene molecules connected by isosorbide and isomannide moieties is presented. Additionally, their electrochemical behavior and their ability to form complexes with [10]cycloparaphenylene ([10]CPP) were investigated. The cyclic voltammetry (CV) results of the fullerene dumbbells demonstrate a high electron affinity, indicating their strong interaction with electron‐donating counterparts such as carbon nanorings, which possess complementary charge and shape properties. To study the thermodynamic and kinetic parameters of complexation, isothermal titration calorimetry (ITC) was employed. NMR titration experiments provided further insights into the binding stoichiometries. Two distinct approaches were utilized to create bridged structures: one based on cyclopropane and the other based on furan. Regardless of the type of linker used, all derivatives formed conventional 2 : 1 complexes denoted as [10]CPP2⊃C60derivative. However, the methano‐dumbbell molecules exhibited distinct binding behavior, resulting in the formation of mono‐ and bis‐pseudorotaxanes, as well as oligomers (polymers). The formation of linear polymers holds significant potential for applications in solar energy conversion processes.
A photochemically promoted intramolecular cyclization of aryl‐, vinyl‐, and alkyliodo allenes has... more A photochemically promoted intramolecular cyclization of aryl‐, vinyl‐, and alkyliodo allenes has been developed. The optimal conditions employed [Ir(ppy)2(dtbbpy)]PF6 (1 mol%) as catalyst affording products with high exo selectivity in moderate to good yields. Chiral substrates showed diastereoselectivity of up to 95/5 favoring trans product.
Enallenylamides have been utilized for the synthesis of heterobicycle[4.2.0]octane derivatives vi... more Enallenylamides have been utilized for the synthesis of heterobicycle[4.2.0]octane derivatives via Ir/hν promoted [2+2] cycloaddition reaction. The reaction specifically targets the distal double bond of the allene moiety, and results in the exclusive formation of the trans product. The process is conducted at room temperature and under an inert atmosphere. An extensive study on the substituent propensities during the cycloaddition step revealed variable effects. Electron‐withdrawing groups conjugated with the double bond participating in the cycloaddition either hindered the process or reduced its yield. Conversely, electron‐donating substituents enhanced the efficiency, resulting in product yields ranging from 60% to 88%. Our study also demonstrated the influence of protecting groups on the reaction pathway.
General. All chemicals were purchased from commercial sources, and used as received unless stated... more General. All chemicals were purchased from commercial sources, and used as received unless stated otherwise. All solvents were dried prior to use according to standard literature protocols. Chromatography purifications were performed using silica gel 60 (Sorbent technologies 40-75 µ m, 200 x 400 mesh). Thin-layer chromatography (TLC) was performed on silica-gel plate w/UV254 (200 µ m). Chromatograms were visualized by UV-light, and also stained using 20% phosphomolybdic acid in ethanol. Melting points were determined on an Electrothermal melting point apparatus in open capillaries and reported uncorrected. 1 H and 13 C NMR spectra were recorded using 500 MHz and 125 MHz a Bruker DRX-500 spectrometer, unless stated otherwise. They were referenced using the solvent residual signal as internal standard. Samples were prepared using CDCl 3 and CD 3 SOCD 3 purchased from Cambridge Isotope Laboratories. The chemical shift values are expressed as δ values and the coupling constants values (J) are in Hertz (Hz). The following abbreviations were used for signal multiplicities: s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; and br, broad. High resolution electron-ionization (HRMS-EI) spectra were recorded on a Micromass Q-TOF2 instrument. Preparation of the Starting Materials. The syntheses of 1-3 are outlined in Schemes S1, S2, and S3. 3-methoxy-5-nitrobenzoic acid was prepared from commercially available 3,5-dinitrobenzoic acid 4 , in a nucleophilic aromatic substitution reaction with LiOCH 3. 1 2,3-dichloroquinoxaline was oxidized with KMnO 4 to yield 5,6-dichloropyrazine-2,3-dicarboxy acid anhydride following a reported procedure. 2 Resorcinarene 15 was obtained in a condensation reaction of resorcinol and dodecanal. 3 Compound 5. To a refluxing solution of 3-methoxy-5-nitrobenzoic acid (2.12 g, 10.7 mmol) and K 2 CO 3 (1.68 g, 12.2 mmol) in anhydrous acetone (20 mL), dimethyl sulfate (2 mL) was added dropwise over a period of 15 minutes. The reaction mixture was refluxed for an additional 12 h, cooled to room temperature, and the solvent was removed in vacuo. The resulting solid residue was purified by column chromatography (SiO 2 , hexanes/EtOAc, 5:1) to afford 1 as a white solid (1.92 g, 84 %).
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
In this study, b-keto esters as readily available bio-based building blocks were used to decorate... more In this study, b-keto esters as readily available bio-based building blocks were used to decorate the C 60 sphere. Generally, cyclopropanated fullerene derivatives are obtained by the standard Bingel-Hirsch procedure. Herein, omitting the iodine from the reaction mixture and adding TEMPO afforded dihydrofuran fused C 60 fullerene derivatives. The mechanism of the reaction shifted from nucleophilic aliphatic substitution to oxidative [3 + 2] cycloaddition via fullerenyl cations as an intermediate. This mechanism is proposed based on a series of control experiments with radical scavengers. Therefore, dihydrofuran-fused C 60 derivatives were selectively obtained in good yields and their structures were established based on UV-Vis, IR, NMR spectroscopy and mass spectrometry. The electrochemical properties of the synthesized compounds were investigated by cyclic voltammetry. DFT calculations were performed in order to investigate the difference in stability, electronic properties and p-electron delocalization between methano and furano fullerenes.
We synthesized three dumbbell-like compounds 2a-c, each containing two C60 groups at the peripher... more We synthesized three dumbbell-like compounds 2a-c, each containing two C60 groups at the periphery and pyromellitic diimide (PMDI) in the middle, and examined their electronic as well as assembly characteristics with both experimental and computational methods. Cyclic voltammetry (CV) measurements revealed that each of three electron-accepting (AAA) triads could accommodate up to eight electrons. Computational studies (density functional theory, DFT) of 2a-c at PBEPBE/6-311G(d,p) level of theory, with B3LYP/6-31G(d) optimized geometries, revealed that HOMO-LUMO energy gaps are similar to those of the model compound [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). Compounds 2a-c were also found to assemble into vesicles and nanoparticles on the copper grid (100-300 nm, TEM), while giving more sizeable aggregates after a deposition on the glass (SEM, > 5 µm). Understanding the packing of 2a-c on various solid substrates, as well as the assembly characteristics in general, is important for tuning the properties and fabrication of electronic/optical devices. On the basis of the results of conformational analysis (MM and DFT calculations), we deduced that different alkyl spacers in 2a-c ought to play a role in π-π interactions between the aromatic components of the triad to guide the packing and therefore morphology of the material.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Plastic waste poses an enormous environmental problem as a result of soil and ocean contamination... more Plastic waste poses an enormous environmental problem as a result of soil and ocean contamination, causing the release of microplastics that end up in humans through the food web. Enzymatic degradation of plastics has emerged as an alternative to traditional recycling processes. In the present work, we used bioinfomatics tools to discover a gene coding for a putative polyester degrading enzyme (polyesterase). The gene was heterologously expressed, purified and biochemically characterized. Furthermore, its ability to degrade polyethylene terephthalate (PET) model substrates and synthetic plastics was assessed.
The excited-state heterolysis of acridinol-based derivatives leads to the release of the OH − ion... more The excited-state heterolysis of acridinol-based derivatives leads to the release of the OH − ion and the formation of the corresponding acridinium cations. To evaluate the parameters that control the reaction barriers, the kinetics of excited-state OH − release from a series of acridinol photobases were studied using transient absorption spectroscopy. The rate constants were obtained in three solvents (methanol, butanol, and isobutanol), and the data were modeled using Marcus theory. The intrinsic reorganization energies obtained from these fits were found to correlate well with the solvent reorganization energies calculated using dielectric continuum model, suggesting that the excited-state OH − release occurs along the solvent reaction coordinate. Furthermore, the ability of acridinol photobases to photoinitiate chemical reactions was demonstrated using the Michael reaction between dimethylmalonate and nitrostyrene.
A range of palladium-catalyzed cross-coupling reactions can be performed using allylic phosphates... more A range of palladium-catalyzed cross-coupling reactions can be performed using allylic phosphates as electrophiles. Both conventional heating and microwave irradiation can be used.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
A study of the synthesis of 4-(substituted phenyl)-6-phenyl-3-cyano-2-pyridones from ethyl 2-cyan... more A study of the synthesis of 4-(substituted phenyl)-6-phenyl-3-cyano-2-pyridones from ethyl 2-cyano-3-(substituted phenyl) acrylates and acetophenone is presented. The 2-pyridones were obtained using conventional as well as microwave synthesis under solvent and solvent-free conditions in domestic and laboratory microwave ovens. The structure of the obtained pyridones was confirmed by m.p., FT-IR, NMR and UV data.
The synthesis and characterization of four dumbbell‐shaped fullerene molecules connected by isoso... more The synthesis and characterization of four dumbbell‐shaped fullerene molecules connected by isosorbide and isomannide moieties is presented. Additionally, their electrochemical behavior and their ability to form complexes with [10]cycloparaphenylene ([10]CPP) were investigated. The cyclic voltammetry (CV) results of the fullerene dumbbells demonstrate a high electron affinity, indicating their strong interaction with electron‐donating counterparts such as carbon nanorings, which possess complementary charge and shape properties. To study the thermodynamic and kinetic parameters of complexation, isothermal titration calorimetry (ITC) was employed. NMR titration experiments provided further insights into the binding stoichiometries. Two distinct approaches were utilized to create bridged structures: one based on cyclopropane and the other based on furan. Regardless of the type of linker used, all derivatives formed conventional 2 : 1 complexes denoted as [10]CPP2⊃C60derivative. However, the methano‐dumbbell molecules exhibited distinct binding behavior, resulting in the formation of mono‐ and bis‐pseudorotaxanes, as well as oligomers (polymers). The formation of linear polymers holds significant potential for applications in solar energy conversion processes.
A photochemically promoted intramolecular cyclization of aryl‐, vinyl‐, and alkyliodo allenes has... more A photochemically promoted intramolecular cyclization of aryl‐, vinyl‐, and alkyliodo allenes has been developed. The optimal conditions employed [Ir(ppy)2(dtbbpy)]PF6 (1 mol%) as catalyst affording products with high exo selectivity in moderate to good yields. Chiral substrates showed diastereoselectivity of up to 95/5 favoring trans product.
Enallenylamides have been utilized for the synthesis of heterobicycle[4.2.0]octane derivatives vi... more Enallenylamides have been utilized for the synthesis of heterobicycle[4.2.0]octane derivatives via Ir/hν promoted [2+2] cycloaddition reaction. The reaction specifically targets the distal double bond of the allene moiety, and results in the exclusive formation of the trans product. The process is conducted at room temperature and under an inert atmosphere. An extensive study on the substituent propensities during the cycloaddition step revealed variable effects. Electron‐withdrawing groups conjugated with the double bond participating in the cycloaddition either hindered the process or reduced its yield. Conversely, electron‐donating substituents enhanced the efficiency, resulting in product yields ranging from 60% to 88%. Our study also demonstrated the influence of protecting groups on the reaction pathway.
General. All chemicals were purchased from commercial sources, and used as received unless stated... more General. All chemicals were purchased from commercial sources, and used as received unless stated otherwise. All solvents were dried prior to use according to standard literature protocols. Chromatography purifications were performed using silica gel 60 (Sorbent technologies 40-75 µ m, 200 x 400 mesh). Thin-layer chromatography (TLC) was performed on silica-gel plate w/UV254 (200 µ m). Chromatograms were visualized by UV-light, and also stained using 20% phosphomolybdic acid in ethanol. Melting points were determined on an Electrothermal melting point apparatus in open capillaries and reported uncorrected. 1 H and 13 C NMR spectra were recorded using 500 MHz and 125 MHz a Bruker DRX-500 spectrometer, unless stated otherwise. They were referenced using the solvent residual signal as internal standard. Samples were prepared using CDCl 3 and CD 3 SOCD 3 purchased from Cambridge Isotope Laboratories. The chemical shift values are expressed as δ values and the coupling constants values (J) are in Hertz (Hz). The following abbreviations were used for signal multiplicities: s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; and br, broad. High resolution electron-ionization (HRMS-EI) spectra were recorded on a Micromass Q-TOF2 instrument. Preparation of the Starting Materials. The syntheses of 1-3 are outlined in Schemes S1, S2, and S3. 3-methoxy-5-nitrobenzoic acid was prepared from commercially available 3,5-dinitrobenzoic acid 4 , in a nucleophilic aromatic substitution reaction with LiOCH 3. 1 2,3-dichloroquinoxaline was oxidized with KMnO 4 to yield 5,6-dichloropyrazine-2,3-dicarboxy acid anhydride following a reported procedure. 2 Resorcinarene 15 was obtained in a condensation reaction of resorcinol and dodecanal. 3 Compound 5. To a refluxing solution of 3-methoxy-5-nitrobenzoic acid (2.12 g, 10.7 mmol) and K 2 CO 3 (1.68 g, 12.2 mmol) in anhydrous acetone (20 mL), dimethyl sulfate (2 mL) was added dropwise over a period of 15 minutes. The reaction mixture was refluxed for an additional 12 h, cooled to room temperature, and the solvent was removed in vacuo. The resulting solid residue was purified by column chromatography (SiO 2 , hexanes/EtOAc, 5:1) to afford 1 as a white solid (1.92 g, 84 %).
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
In this study, b-keto esters as readily available bio-based building blocks were used to decorate... more In this study, b-keto esters as readily available bio-based building blocks were used to decorate the C 60 sphere. Generally, cyclopropanated fullerene derivatives are obtained by the standard Bingel-Hirsch procedure. Herein, omitting the iodine from the reaction mixture and adding TEMPO afforded dihydrofuran fused C 60 fullerene derivatives. The mechanism of the reaction shifted from nucleophilic aliphatic substitution to oxidative [3 + 2] cycloaddition via fullerenyl cations as an intermediate. This mechanism is proposed based on a series of control experiments with radical scavengers. Therefore, dihydrofuran-fused C 60 derivatives were selectively obtained in good yields and their structures were established based on UV-Vis, IR, NMR spectroscopy and mass spectrometry. The electrochemical properties of the synthesized compounds were investigated by cyclic voltammetry. DFT calculations were performed in order to investigate the difference in stability, electronic properties and p-electron delocalization between methano and furano fullerenes.
We synthesized three dumbbell-like compounds 2a-c, each containing two C60 groups at the peripher... more We synthesized three dumbbell-like compounds 2a-c, each containing two C60 groups at the periphery and pyromellitic diimide (PMDI) in the middle, and examined their electronic as well as assembly characteristics with both experimental and computational methods. Cyclic voltammetry (CV) measurements revealed that each of three electron-accepting (AAA) triads could accommodate up to eight electrons. Computational studies (density functional theory, DFT) of 2a-c at PBEPBE/6-311G(d,p) level of theory, with B3LYP/6-31G(d) optimized geometries, revealed that HOMO-LUMO energy gaps are similar to those of the model compound [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). Compounds 2a-c were also found to assemble into vesicles and nanoparticles on the copper grid (100-300 nm, TEM), while giving more sizeable aggregates after a deposition on the glass (SEM, > 5 µm). Understanding the packing of 2a-c on various solid substrates, as well as the assembly characteristics in general, is important for tuning the properties and fabrication of electronic/optical devices. On the basis of the results of conformational analysis (MM and DFT calculations), we deduced that different alkyl spacers in 2a-c ought to play a role in π-π interactions between the aromatic components of the triad to guide the packing and therefore morphology of the material.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Plastic waste poses an enormous environmental problem as a result of soil and ocean contamination... more Plastic waste poses an enormous environmental problem as a result of soil and ocean contamination, causing the release of microplastics that end up in humans through the food web. Enzymatic degradation of plastics has emerged as an alternative to traditional recycling processes. In the present work, we used bioinfomatics tools to discover a gene coding for a putative polyester degrading enzyme (polyesterase). The gene was heterologously expressed, purified and biochemically characterized. Furthermore, its ability to degrade polyethylene terephthalate (PET) model substrates and synthetic plastics was assessed.
The excited-state heterolysis of acridinol-based derivatives leads to the release of the OH − ion... more The excited-state heterolysis of acridinol-based derivatives leads to the release of the OH − ion and the formation of the corresponding acridinium cations. To evaluate the parameters that control the reaction barriers, the kinetics of excited-state OH − release from a series of acridinol photobases were studied using transient absorption spectroscopy. The rate constants were obtained in three solvents (methanol, butanol, and isobutanol), and the data were modeled using Marcus theory. The intrinsic reorganization energies obtained from these fits were found to correlate well with the solvent reorganization energies calculated using dielectric continuum model, suggesting that the excited-state OH − release occurs along the solvent reaction coordinate. Furthermore, the ability of acridinol photobases to photoinitiate chemical reactions was demonstrated using the Michael reaction between dimethylmalonate and nitrostyrene.
A range of palladium-catalyzed cross-coupling reactions can be performed using allylic phosphates... more A range of palladium-catalyzed cross-coupling reactions can be performed using allylic phosphates as electrophiles. Both conventional heating and microwave irradiation can be used.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
A study of the synthesis of 4-(substituted phenyl)-6-phenyl-3-cyano-2-pyridones from ethyl 2-cyan... more A study of the synthesis of 4-(substituted phenyl)-6-phenyl-3-cyano-2-pyridones from ethyl 2-cyano-3-(substituted phenyl) acrylates and acetophenone is presented. The 2-pyridones were obtained using conventional as well as microwave synthesis under solvent and solvent-free conditions in domestic and laboratory microwave ovens. The structure of the obtained pyridones was confirmed by m.p., FT-IR, NMR and UV data.
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