Solar-Driven Glucose Isomerization into Fructose via Transient Lewis Acid–Base Active Sites

ACS Catalysis ◽  
2021 ◽  
pp. 12170-12178
Author(s):  
Jiu Wang ◽  
Heng Zhao ◽  
Bicheng Zhu ◽  
Stephen Larter ◽  
Shaowen Cao ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Active Sites ◽  
Acid Base ◽  
Glucose Isomerization

scholarly journals Interplay of hemilability and redox activity in models of hydrogenase active sites

2017 ◽  
Vol 114 (46) ◽  
pp. E9775-E9782 ◽  
Author(s):  
Shengda Ding ◽  
Pokhraj Ghosh ◽  
Marcetta Y. Darensbourg ◽  
Michael B. Hall
Keyword(s):  
Lewis Acid ◽  
Hydrogen Evolution Reaction ◽  
Resting State ◽  
Active Sites ◽  
Reductive Elimination ◽  
Lewis Base ◽  
Redox Activity ◽  
Production Mechanism ◽  
Acid Base ◽  
Redox Active

The hydrogen evolution reaction, as catalyzed by two electrocatalysts [M(N2S2)·Fe(NO)2]+, [Fe-Fe]+ (M = Fe(NO)) and [Ni-Fe]+ (M = Ni) was investigated by computational chemistry. As nominal models of hydrogenase active sites, these bimetallics feature two kinds of actor ligands: Hemilabile, MN2S2 ligands and redox-active, nitrosyl ligands, whose interplay guides the H2 production mechanism. The requisite base and metal open site are masked in the resting state but revealed within the catalytic cycle by cleavage of the MS–Fe(NO)2 bond from the hemilabile metallodithiolate ligand. Introducing two electrons and two protons to [Ni-Fe]+ produces H2 from coupling a hydride temporarily stored on Fe(NO)2 (Lewis acid) and a proton accommodated on the exposed sulfur of the MN2S2 thiolate (Lewis base). This Lewis acid–base pair is initiated and preserved by disrupting the dative donation through protonation on the thiolate or reduction on the thiolate-bound metal. Either manipulation modulates the electron density of the pair to prevent it from reestablishing the dative bond. The electron-buffering nitrosyl’s role is subtler as a bifunctional electron reservoir. With more nitrosyls as in [Fe-Fe]+, accumulated electronic space in the nitrosyls’ π*-orbitals makes reductions easier, but redirects the protonation and reduction to sites that postpone the actuation of the hemilability. Additionally, two electrons donated from two nitrosyl-buffered irons, along with two external electrons, reduce two protons into two hydrides, from which reductive elimination generates H2.

Cleaving DNA-model phosphodiester with Lewis acid–base catalytic sites in bifunctional Zr–MOFs

2019 ◽  
Vol 48 (23) ◽  
pp. 8044-8048 ◽  
Author(s):  
Ying-Hua Zhou ◽  
Zhiyan Zhang ◽  
Margaret Patrick ◽  
Fan Yang ◽  
Rangling Wei ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Active Sites ◽  
Lewis Base ◽  
Zinc Hydroxide ◽  
Acid Base ◽  
Enhanced Activity ◽  
Nitrophenyl Phosphate ◽  
Catalytic Sites ◽  
Catalytic Active Sites ◽  
Hydrolysis Of

UiO-67-bpydc-Zn with isolated multi-catalytic active sites was fabricated as a catalyst for the hydrolysis of bis(p-nitrophenyl) phosphate as a DNA model. The enhanced activity may likely be attributed to the cooperation effects between the Lewis acid from the zirconium center at the node and the zinc hydroxide Lewis base in the linkers.

scholarly journals Enhanced Catalysis of Pt3 Clusters Supported on Graphene for N–H Bond Dissociation

CCS Chemistry ◽  
2019 ◽  
Vol 1 (2) ◽  
pp. 215-225 ◽  
Author(s):  
Chaonan Cui ◽  
Zhixun Luo ◽  
Jiannian Yao
Keyword(s):  
Density Of States ◽  
Lewis Acid ◽  
Active Sites ◽  
Metal Cluster ◽  
Catalytic Performance ◽  
Pristine Graphene ◽  
Acid Base ◽  
Activation Barriers ◽  
Bond Dissociation ◽  
Defective Graphene

We report an in-depth study of catalytic N–H bond dissociation with typical platinum clusters on graphene supports. Among all the pristine graphene- and defective graphene-supported Pt clusters of different sizes that were studied, the Pt 3/G cluster possesses the highest reactivity and lowest activation barriers for each step of N–H dissociation in the decomposition of ammonia. In analyzing the reaction coordinates and projected density of states of the outermost orbitals, we found that the standing triangular Pt 3 on graphene creates prominent Lewis acid/base pair sites, which accommodate the adsorption and subsequent dissociation of *NH x . In comparison, Pt 1 lacks complementary active sites (CAS), causing it to be adverse to nucleophilic reactions, and in contrast, the Pt 13 cluster has weakened interactions and depleted charge density from the support, resulting in the elimination of the CAS effect. A stable pyramid-structured Pt 4 also develops Lewis acid/base sites, especially on defective graphene, but the density of states is still lower than the stand-up Pt 3/G. These findings strongly demonstrate the importance and necessity of cluster active sites for catalytic reactions of polar molecules, novel three-atoms metal cluster catalysis, and the selectivity and catalytic performance in the designing of ammonia fuel cells.

Solvation and redox properties of [Co(en)3]3+-[Co(en)3]2+ system

1980 ◽  
Vol 45 (2) ◽  
pp. 335-338 ◽  
Author(s):  
Adéla Kotočová ◽  
Ulrich Mayer
Keyword(s):  
Hydrogen Bond ◽  
Lewis Acid ◽  
Specific Interaction ◽  
Redox Properties ◽  
Solvation Effect ◽  
Interacting Particles ◽  
Acid Base ◽  
Polar Solvents ◽  
Oxidation Reduction ◽  
Solvent Molecules

The solvation effect of a number of nonaqueous polar solvents was studied on the oxidation-reduction properties of the [Co(en)3]3+-[Co(en)3]2+ system. Interactions of these ions with the solvent molecules are discussed in terms of their coordination, which is accompanied by a specific interaction of the Lewis acid-base type, namely formation of a hydrogen bond between the interacting particles. This is the main controlling factor of the redox properties of the studied system.

Chalcogen versus Dative Bonding in [SF3]+ Lewis Acid–Base Adducts: [SF3(NCCH3)2]+, [SF3(NC5H5)2]+, and [SF3(phen)]+ (phen = 1,10-phenanthroline)

2021 ◽  
Vol 60 (6) ◽  
pp. 3893-3901
Author(s):  
Douglas Turnbull ◽  
Praveen Chaudhary ◽  
Paul Hazendonk ◽  
Stacey D. Wetmore ◽  
Michael Gerken
Keyword(s):  
Lewis Acid ◽  
Acid Base

scholarly journals Lewis acid / Base-free Strategy for the Synthesis of 2-Arylthio and Selenyl Benzothiazole / Thiazole and Imidazole

2021 ◽  
Vol 27 (1) ◽  
pp. 17-23
Author(s):  
Guniganti Balakishan ◽  
Gullapalli Kumaraswamy ◽  
Vykunthapu Narayanarao ◽  
Pagilla Shankaraiah
Keyword(s):  
Lewis Acid ◽  
Bond Formation ◽  
Acid Base ◽  
Mechanistic Pathway ◽  
Wide Range ◽  
Acid And Base ◽  
Lewis Acid And Base ◽  
Sulfur Bond

Abstract A Cu(II)-catalyzed Csp2-Se and Csp2-Sulfur bond formation was achieved with moderate to good yields without the aid of Lewis acid and base. The reaction is compatible with a wide range of heterocycles such as benzothiazole, thiazole, and imidazole. Also, this typical protocol is found to be active in thio-selenation via S-H activation. Additionally, we proposed a plausible mechanistic pathway involving Cu(III) putative intermediate.

scholarly journals Novel hydrogen chemisorption properties of amorphous ceramic compounds consisting of p-block elements: exploring Lewis acid-base Al–N pair site formed in-situ within polymer-derived silicon-aluminum-nitrogen-based system

2021 ◽  
Author(s):  
Shotaro Tada ◽  
Norifumi Asakuma ◽  
Shiori Ando ◽  
Toru Asaka ◽  
Yusuke Daiko ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Active Site ◽  
Hydrogen Chemisorption ◽  
Acid Base ◽  
Polymer Derived Ceramics ◽  
System P ◽  
Ceramic Compounds ◽  
The Relationship

This paper reports on the relationship between the H2 chemisorption properties and reversible structural reorientation of the possible active site around Al formed in-situ within polymer-derived ceramics (PDCs) based on...

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