ACS Organic & Inorganic Au最新文献

Amide hydrogenation is an important process for producing amines, with the development of efficient heterogeneous catalysts relying on the creation of bimetallic active sites where the two components interact synergistically. In this study, we develop a method for preparing catalysts using ligand-functionalized organometallic polyoxometalates by synthesizing a Rh–Mo organometallic polyoxometalate, [(RhCp^E)₄Mo₄O₁₆] (Cp^E = C₅(CH₃)₃(COOC₂H₅)₂), with Rh–O–Mo interfacial structures and ethoxycarbonyl-functionalized ligands as a catalyst precursor. The activity of supported Rh–Mo catalysts for amide hydrogenation depend on the precursor used, with [(RhCp^E)₄Mo₄O₁₆] showing the highest activity, followed by [(RhCp*)₄Mo₄O₁₆] (Cp* = C₅(CH₃)₅), and then RhCl₃ combined with (NH₄)₆[Mo₇O₂₄]·4H₂O. The catalyst prepared from [(RhCp^E)₄Mo₄O₁₆] effectively hydrogenates tertiary, secondary, and primary amides under mild conditions (0.8 MPa H₂, 353–393 K), demonstrating a high activity and selectivity (conversion: 97%, selectivity: 76%) for primary amide hydrogenation under NH₃-free conditions. Furthermore, we determine that carbonyl oxygen atoms in Cp^E ligands contribute to the electrostatic interaction with Al₂O₃, leading to the high dispersibility of [(RhCp^E)₄Mo₄O₁₆] on the support. We conclude that the high efficiency of [(RhCp^E)₄Mo₄O₁₆] as a catalyst precursor originates from the effective formation of Rh/Mo interfacial active sites, which is assisted by the electrostatic interaction between the Cp^E ligands and support.

Amide hydrogenation is an important process for producing amines, with the development of efficient heterogeneous catalysts relying on the creation of bimetallic active sites where the two components interact synergistically. In this study, we develop a method for preparing catalysts using ligand-functionalized organometallic polyoxometalates by synthesizing a Rh-Mo organometallic polyoxometalate, [(RhCp^E)₄Mo₄O₁₆] (Cp^E = C₅(CH₃)₃(COOC₂H₅)₂), with Rh-O-Mo interfacial structures and ethoxycarbonyl-functionalized ligands as a catalyst precursor. The activity of supported Rh-Mo catalysts for amide hydrogenation depend on the precursor used, with [(RhCp^E)₄Mo₄O₁₆] showing the highest activity, followed by [(RhCp*)₄Mo₄O₁₆] (Cp* = C₅(CH₃)₅), and then RhCl₃ combined with (NH₄)₆[Mo₇O₂₄]·4H₂O. The catalyst prepared from [(RhCp^E)₄Mo₄O₁₆] effectively hydrogenates tertiary, secondary, and primary amides under mild conditions (0.8 MPa H₂, 353-393 K), demonstrating a high activity and selectivity (conversion: 97%, selectivity: 76%) for primary amide hydrogenation under NH₃-free conditions. Furthermore, we determine that carbonyl oxygen atoms in Cp^E ligands contribute to the electrostatic interaction with Al₂O₃, leading to the high dispersibility of [(RhCp^E)₄Mo₄O₁₆] on the support. We conclude that the high efficiency of [(RhCp^E)₄Mo₄O₁₆] as a catalyst precursor originates from the effective formation of Rh/Mo interfacial active sites, which is assisted by the electrostatic interaction between the Cp^E ligands and support.

Electro-organic chemistry presents a promising frontier in drug discovery and early development, facilitating novel reactivity aligned with green chemistry principles. Despite this, electrochemistry is not widely used as a synthesis and manufacturing tool in drug discovery or development. This overview seeks to identify key areas that require additional research to make synthetic electrochemistry more accessible to chemists in drug discovery and early development and provide potential solutions. This includes expanding the reaction scope, simplifying rapid scale-up, developing electrode materials, and improving knowledge transfer to aid reproducibility and increase the awareness of electrochemistry. The integration of electro-organic synthesis into drug discovery and development holds the potential to enable efficient, sustainable routes toward future medicines faster than ever.

Electro-organic chemistry presents a promising frontier in drug discovery and early development, facilitating novel reactivity aligned with green chemistry principles. Despite this, electrochemistry is not widely used as a synthesis and manufacturing tool in drug discovery or development. This overview seeks to identify key areas that require additional research to make synthetic electrochemistry more accessible to chemists in drug discovery and early development and provide potential solutions. This includes expanding the reaction scope, simplifying rapid scale-up, developing electrode materials, and improving knowledge transfer to aid reproducibility and increase the awareness of electrochemistry. The integration of electro-organic synthesis into drug discovery and development holds the potential to enable efficient, sustainable routes toward future medicines faster than ever.

Altermagnetism was very recently identified as a new type of magnetic phase beyond the conventional dichotomy of ferromagnetism (FM) and antiferromagnetism (AFM). Its globally compensated magnetization and directional spin polarization promise new properties such as spin-polarized conductivity, spin-transfer torque, anomalous Hall effect, tunneling, and giant magnetoresistance that are highly useful for the next-generation memory devices, magnetic detectors, and energy conversion. Though this area has been historically led by the thin-film community, the identification of altermagnetism ultimately relies on precise magnetic structure determination, which can be most efficiently done in bulk materials. Our review, written from a materials chemistry perspective, intends to encourage materials and solid-state chemists to make contributions to this emerging topic through new materials discovery by leveraging neutron diffraction to determine the magnetic structures as well as bulk crystal growth for exploring exotic properties. We first review the symmetric classification for the identification of altermagnets with a summary of chemical principles and design rules, followed by a discussion of the unique physical properties in relation to crystal and magnetic structural symmetry. Several major families of compounds in which altermagnets have been identified are then reviewed. We conclude by giving an outlook for future directions.

Altermagnetism was very recently identified as a new type of magnetic phase beyond the conventional dichotomy of ferromagnetism (FM) and antiferromagnetism (AFM). Its globally compensated magnetization and directional spin polarization promise new properties such as spin-polarized conductivity, spin-transfer torque, anomalous Hall effect, tunneling, and giant magnetoresistance that are highly useful for the next-generation memory devices, magnetic detectors, and energy conversion. Though this area has been historically led by the thin-film community, the identification of altermagnetism ultimately relies on precise magnetic structure determination, which can be most efficiently done in bulk materials. Our review, written from a materials chemistry perspective, intends to encourage materials and solid-state chemists to make contributions to this emerging topic through new materials discovery by leveraging neutron diffraction to determine the magnetic structures as well as bulk crystal growth for exploring exotic properties. We first review the symmetric classification for the identification of altermagnets with a summary of chemical principles and design rules, followed by a discussion of the unique physical properties in relation to crystal and magnetic structural symmetry. Several major families of compounds in which altermagnets have been identified are then reviewed. We conclude by giving an outlook for future directions.

Carbon dioxide (CO₂) is an abundant and useful C₁ feedstock for electrocarboxylation, a process that incorporates a carboxyl moiety into an organic molecule. In this work, three first-row transition metal CO₂ reduction electrocatalysts, NiPDI^iPr (1), NiTPA (2), and Fe(salenCl₄) (3), were explored as electrocarboxylation catalysts with benzyl chloride as a substrate. The cyclic voltammograms of all three catalysts showed current enhancements in the presence of benzyl chloride under a CO₂ atmosphere. Introduction of DMAP as additives showed further current enhancement. Electrolyses with one-compartment cell generated a moderate yield of phenylacetic acid. Addition of MgBr₂ was proven to be crucial to the formation of the carboxylate product. While the yield of carboxylation was moderate, this work showed an example of electrocarboxylation of benzyl chloride without using a metal electrode or sacrificial anode, which could lead to a more sustainable carboxylation methodology.

Carbon dioxide (CO₂) is an abundant and useful C₁ feedstock for electrocarboxylation, a process that incorporates a carboxyl moiety into an organic molecule. In this work, three first-row transition metal CO₂ reduction electrocatalysts, NiPDI^iPr (1), NiTPA (2), and Fe(salenCl₄) (3), were explored as electrocarboxylation catalysts with benzyl chloride as a substrate. The cyclic voltammograms of all three catalysts showed current enhancements in the presence of benzyl chloride under a CO₂ atmosphere. Introduction of DMAP as additives showed further current enhancement. Electrolyses with one-compartment cell generated a moderate yield of phenylacetic acid. Addition of MgBr₂ was proven to be crucial to the formation of the carboxylate product. While the yield of carboxylation was moderate, this work showed an example of electrocarboxylation of benzyl chloride without using a metal electrode or sacrificial anode, which could lead to a more sustainable carboxylation methodology.

It is well-known that addition of a cationic functional group to a molecule lowers the necessary applied potential for an electron transfer (ET) event. This report studies the effect of a proton (a cation) on the mechanism of electrochemically driven hydride transfer (HT) catalysis. Protonated, air-stable [HFe₄N(triethyl phosphine (PEt₃))₄(CO)₈] (H4) was synthesized by reaction of PEt₃ with [Fe₄N(CO)₁₂]⁻ (A^–) in tetrahydrofuran, with addition of benzoic acid to the reaction mixture. The reduction potential of H4 is −1.70 V vs SCE which is 350 mV anodic of the reduction potential for 4^–. Reactivity studies are consistent with HT to CO₂ or to H⁺ (carbonic acid), as the chemical event following ET, when the electrocatalysis is performed under 1 atm of CO₂ or N₂, respectively. Taken together, the chemical and electrochemical studies of mechanism suggest an ECEC mechanism for the reduction of CO₂ to formate or H⁺ to H₂, promoted by H4. This stands in contrast to an ET, two chemical steps, followed by an ET (ECCE) mechanism that is promoted by the less electron rich catalyst A^–, since A^– must be reduced to A^2– before HA^– can be accessed.

It is well-known that addition of a cationic functional group to a molecule lowers the necessary applied potential for an electron transfer (ET) event. This report studies the effect of a proton (a cation) on the mechanism of electrochemically driven hydride transfer (HT) catalysis. Protonated, air-stable [HFe₄N(triethyl phosphine (PEt₃))₄(CO)₈] (H4) was synthesized by reaction of PEt₃ with [Fe₄N(CO)₁₂]^- (A ^-) in tetrahydrofuran, with addition of benzoic acid to the reaction mixture. The reduction potential of H4 is -1.70 V vs SCE which is 350 mV anodic of the reduction potential for 4 ^-. Reactivity studies are consistent with HT to CO₂ or to H⁺ (carbonic acid), as the chemical event following ET, when the electrocatalysis is performed under 1 atm of CO₂ or N₂, respectively. Taken together, the chemical and electrochemical studies of mechanism suggest an ECEC mechanism for the reduction of CO₂ to formate or H⁺ to H₂, promoted by H4. This stands in contrast to an ET, two chemical steps, followed by an ET (ECCE) mechanism that is promoted by the less electron rich catalyst A ^-, since A ^- must be reduced to A ^2- before HA ^- can be accessed.