This method thus presents a new simple approach for the manufacturing of antifouling coatings for biomedical and biotechnological applications.Herein, we report the physicochemical and structural properties of a new solubility-switchable ionic liquid (IL) comprising the glycerammonium (GA) cation with a hydrophilic group, the GA cation attached to an acetal-based protective group [protected GA (PGA)], and bis(trifluoromethanesulfonyl)amide (TFSA). The interionic volumes (Vinter) of the hydrophobic [PGA][TFSA] and hydrophilic [GA][TFSA] ILs were evaluated based on solution density, revealing weaker ion-ion interactions in these relative to conventional ILs. The [PGA][TFSA] and [GA][TFSA] also exhibit poor ion-conducting properties, with up to an order of magnitude lower ionic conductivity (σ) and self-diffusion coefficient (D), as compared with conventional ILs. Radial distribution functions derived from high-energy X-ray total scattering experiments [Gexp(r)] and molecular dynamics (MD) simulations [GMD(r)] indicate that nearest-neighbor ion-ion interactions in the [PGA][TFSA] and [GA][TFSA] are comparable to those in imidazolium-based IL. Conversely, these are appreciably weakened at the second- and third-neighbors and thus less structured in the long range (r > 12 Å) and very different from the highly ordered imidazolium IL. The atom-atom pair correlation function derived from the MD simulations disclose that at a local scale, specific interactions are absent, with only an electrostatic interaction in the [PGA][TFSA], whereas the GA cations interact with TFSA anions via hydrogen bonding of diol groups in the GA and O atoms in the TFSA. No hydrogen bonding group within the PGA cation leads to weak ion-hydration resulting in a phase separation of [PGA][TFSA] and water; in contrast, the GA cations are easily hydrogen-bonded with water molecules to be miscible in aqueous solutions.Ruthenium (II) complexes with N-heterocyclic carbenes (NHC) are commonly used as efficient catalysts in hydrogenation of olefins with simultaneous intramolecular C-H activation. Using the DFT approach, we have investigated the entire hydrogenation reaction pathway for four new potential catalysts and ethylene, a model substrate. Our calculations imply that the dissociation of phosphine is the rate-limiting step of hydrogenation, contrary to recent computational results. We also found that catalysts bearing NHCs with aliphatic and aromatic side groups are energetically favorable over other aliphatic cyclohexyl-substituted NHC. To examine how electronic properties of various catalysts influence the energetic barrier in the crucial steps of the reaction, we applied the Noncovalent Interaction analysis, which allowed us to reveal crucial interactions which stabilize/destabilize important intermediates and transition states in the hydrogenation reaction.The electron transfer (ET) reaction of ferrocene and ferricyanide at water-dichloromethane interface, a typical liquid-liquid ET in electrochemistry, was intensively investigated with three-dimensional free energy surface that fully describes the transport, association and solvent fluctuation in the ET processes. The calculated free energy surface provides the comprehensive picture of the ET mechanism at the liquid-liquid interface. The present calculation revealed the heterogeneous route of ET that takes place over the interface, rather than the homogeneous one. The present conclusion is found to be consistent to previous result of electrochemical experiment by careful reexamination of the analysis.Dynamic electrostatic catalytic field (DECF) vectors derived from transition state and reactant wavefunctions for the two-step reaction occurring within ketosteroid isomerase (KSI) have been calculated using MP2/aug-cc-pVTZ and lower theory levels to determine the magnitude of the catalytic effect and the optimal directions of proton transfers in the KSI hydrogen-bond network. The most surprising and meaningful finding is that the KSI catalytic activity is enhanced by proton dislocations proceeding in opposite directions for each of the two consecutive reaction steps in the same hydrogen network. Such a mechanism allows an ultrafast switching of the catalytic proton wire environment, possibly related to the exceptionally high KSI catalytic power.The Belousov-Zhabotinsky (BZ) reaction shows temporal or spatiotemporal structures such as redox oscillation of the catalyst, [ruthenium(II)tris(2,2'-bipyridine)][PF6]2 ([Ru(bpy)3][PF6]2). In this study, autonomously oscillating hydrogel microspheres (microgels) were investigated, which show swelling/deswelling oscillation induced by the redox oscillation of the BZ reaction inside the gel. Despite the periodically and autonomously induced oscillation that does not require an external stimulus, it has not been possible to perform any manipulation of the oscillatory behavior over time. The results of the present study show that it is possible to reversibly switch the microgel oscillations from an "on" active state of the BZ reaction to an "off" inactive state by changing the temperature in combination with thermoresponsive microgels. To realize on-demand switching, the construction of double-shell structures is crucial; the thermoresponsive first shell allows the microgels to modulate the diffusion of the substrates or intermediates in the BZ reaction, while the second shell maintains colloidal stability under high temperatures and high ion concentrations. The functionalized double-shell microgels were prepared via multistep seeded precipitation polymerization. The oscillatory switching behavior of the BZ reaction was observed directly and evaluated by ultraviolet-visible (UV-vis) spectroscopy. The central concept of this study, i.e., "on-off switching" can be expected to benefit the development of advanced bioinspired materials.The Wittig reaction between triphenylphosphine methylide and benzaldehyde has been studied both from conceptual and computational approaches. https://www.selleckchem.com/products/i-bet-762.html The supernucleophilic character of ylide accounts for the feasibly of the initial nucleophilic attack. The nature of bonding driving the formation of the first oxaphosphetane (OPA) intermediate in such a domino reaction, is examined within a topological-based bonding evolution theory perspective. The sequence of the electronic flow associated to the changes in electron density support a rationalization via two main electronic stages characterizing the single kinetic step first, the C-C bond formation, which takes place via donation of electron density of the ylide carbon to the carbonyl carbon of benzaldehyde at a C-C distance of 2.02 Å, is formally associated to the transition state region; then, the P-O bond formation via the donation of electron density of the non-bonding region of the carbonyl oxygen to phosphorus at a P-O distance of 2.06 Å, is located at the end of the reaction path.
This method thus presents a new simple approach for the manufacturing of antifouling coatings for biomedical and biotechnological applications.Herein, we report the physicochemical and structural properties of a new solubility-switchable ionic liquid (IL) comprising the glycerammonium (GA) cation with a hydrophilic group, the GA cation attached to an acetal-based protective group [protected GA (PGA)], and bis(trifluoromethanesulfonyl)amide (TFSA). The interionic volumes (Vinter) of the hydrophobic [PGA][TFSA] and hydrophilic [GA][TFSA] ILs were evaluated based on solution density, revealing weaker ion-ion interactions in these relative to conventional ILs. The [PGA][TFSA] and [GA][TFSA] also exhibit poor ion-conducting properties, with up to an order of magnitude lower ionic conductivity (σ) and self-diffusion coefficient (D), as compared with conventional ILs. Radial distribution functions derived from high-energy X-ray total scattering experiments [Gexp(r)] and molecular dynamics (MD) simulations [GMD(r)] indicate that nearest-neighbor ion-ion interactions in the [PGA][TFSA] and [GA][TFSA] are comparable to those in imidazolium-based IL. Conversely, these are appreciably weakened at the second- and third-neighbors and thus less structured in the long range (r > 12 Å) and very different from the highly ordered imidazolium IL. The atom-atom pair correlation function derived from the MD simulations disclose that at a local scale, specific interactions are absent, with only an electrostatic interaction in the [PGA][TFSA], whereas the GA cations interact with TFSA anions via hydrogen bonding of diol groups in the GA and O atoms in the TFSA. No hydrogen bonding group within the PGA cation leads to weak ion-hydration resulting in a phase separation of [PGA][TFSA] and water; in contrast, the GA cations are easily hydrogen-bonded with water molecules to be miscible in aqueous solutions.Ruthenium (II) complexes with N-heterocyclic carbenes (NHC) are commonly used as efficient catalysts in hydrogenation of olefins with simultaneous intramolecular C-H activation. Using the DFT approach, we have investigated the entire hydrogenation reaction pathway for four new potential catalysts and ethylene, a model substrate. Our calculations imply that the dissociation of phosphine is the rate-limiting step of hydrogenation, contrary to recent computational results. We also found that catalysts bearing NHCs with aliphatic and aromatic side groups are energetically favorable over other aliphatic cyclohexyl-substituted NHC. To examine how electronic properties of various catalysts influence the energetic barrier in the crucial steps of the reaction, we applied the Noncovalent Interaction analysis, which allowed us to reveal crucial interactions which stabilize/destabilize important intermediates and transition states in the hydrogenation reaction.The electron transfer (ET) reaction of ferrocene and ferricyanide at water-dichloromethane interface, a typical liquid-liquid ET in electrochemistry, was intensively investigated with three-dimensional free energy surface that fully describes the transport, association and solvent fluctuation in the ET processes. The calculated free energy surface provides the comprehensive picture of the ET mechanism at the liquid-liquid interface. The present calculation revealed the heterogeneous route of ET that takes place over the interface, rather than the homogeneous one. The present conclusion is found to be consistent to previous result of electrochemical experiment by careful reexamination of the analysis.Dynamic electrostatic catalytic field (DECF) vectors derived from transition state and reactant wavefunctions for the two-step reaction occurring within ketosteroid isomerase (KSI) have been calculated using MP2/aug-cc-pVTZ and lower theory levels to determine the magnitude of the catalytic effect and the optimal directions of proton transfers in the KSI hydrogen-bond network. The most surprising and meaningful finding is that the KSI catalytic activity is enhanced by proton dislocations proceeding in opposite directions for each of the two consecutive reaction steps in the same hydrogen network. Such a mechanism allows an ultrafast switching of the catalytic proton wire environment, possibly related to the exceptionally high KSI catalytic power.The Belousov-Zhabotinsky (BZ) reaction shows temporal or spatiotemporal structures such as redox oscillation of the catalyst, [ruthenium(II)tris(2,2'-bipyridine)][PF6]2 ([Ru(bpy)3][PF6]2). In this study, autonomously oscillating hydrogel microspheres (microgels) were investigated, which show swelling/deswelling oscillation induced by the redox oscillation of the BZ reaction inside the gel. Despite the periodically and autonomously induced oscillation that does not require an external stimulus, it has not been possible to perform any manipulation of the oscillatory behavior over time. The results of the present study show that it is possible to reversibly switch the microgel oscillations from an "on" active state of the BZ reaction to an "off" inactive state by changing the temperature in combination with thermoresponsive microgels. To realize on-demand switching, the construction of double-shell structures is crucial; the thermoresponsive first shell allows the microgels to modulate the diffusion of the substrates or intermediates in the BZ reaction, while the second shell maintains colloidal stability under high temperatures and high ion concentrations. The functionalized double-shell microgels were prepared via multistep seeded precipitation polymerization. The oscillatory switching behavior of the BZ reaction was observed directly and evaluated by ultraviolet-visible (UV-vis) spectroscopy. The central concept of this study, i.e., "on-off switching" can be expected to benefit the development of advanced bioinspired materials.The Wittig reaction between triphenylphosphine methylide and benzaldehyde has been studied both from conceptual and computational approaches. https://www.selleckchem.com/products/i-bet-762.html The supernucleophilic character of ylide accounts for the feasibly of the initial nucleophilic attack. The nature of bonding driving the formation of the first oxaphosphetane (OPA) intermediate in such a domino reaction, is examined within a topological-based bonding evolution theory perspective. The sequence of the electronic flow associated to the changes in electron density support a rationalization via two main electronic stages characterizing the single kinetic step first, the C-C bond formation, which takes place via donation of electron density of the ylide carbon to the carbonyl carbon of benzaldehyde at a C-C distance of 2.02 Å, is formally associated to the transition state region; then, the P-O bond formation via the donation of electron density of the non-bonding region of the carbonyl oxygen to phosphorus at a P-O distance of 2.06 Å, is located at the end of the reaction path.
0 Comments
0 Shares
105 Views
0 Reviews
