scholarly journals Nitrogen-neighboured single cobalt sites enable heterogeneous oxidase-type catalysis

2022 ◽  
Author(s):  
Yong Cao ◽  
Qi zhang ◽  
Mi Peng ◽  
Zirui Gao ◽  
Wendi Guo ◽  
...  
Keyword(s):  
Aerobic Oxidation ◽  
Solid Matrix ◽  
Chemical Transformations ◽  
Ambient Conditions ◽  
Catalytic Systems ◽  
New Class ◽  
O2 Reduction ◽  
Scalable Synthesis ◽  
Complex Knowledge ◽  
Pyridinic N

Abstract Development of biomimetic catalytic systems that can imitate or even surpass natural enzymes remains an ongoing challenge 1–3. This is particularly true in the context of accessing non-natural reactions by bioinspired approaches, which offer intriguing possibilities for benign and affordable chemical synthesis 4. Exploiting the untapped potential of inorganic solids by translating complex knowledge in (bio)molecular-based systems may constitute a potentially useful strategy for such purpose 5, but efforts to capitalize on the minimum catalytic unit of a versatile solid matrix have been largely unsuccessful. Here, we show how an all-inorganic biomimetic system bearing robust nitrogen-neighboured single cobalt site/pyridinic-N site (Co-N4/Py-N) pairs can act cooperatively as an oxidase mimic, which renders an engaged coupling of oxygen (O2) reduction with synthetically beneficial chemical transformations. By developing this broadly applicable platform, the scalable synthesis of greater than 100 industrially and pharmaceutically appealing O-silylated compounds via the unprecedented aerobic oxidation of hydrosilane under ambient conditions is demonstrated. Moreover, this heterogeneous oxidase mimic also offers potential for expanding the catalytic scope of enzymatic synthesis. We anticipate that the strategy demonstrated here will pave a new avenue for understanding the underlying nature of redox enzymes and open up a new class of material systems for artificial biomimetics.

Study of aerobic oxidation of phenyl PtII complexes (dpms)PtIIPh(L) (dpms = di(2-pyridyl)methanesulfonate; L = water, methanol, or aniline)

2009 ◽  
Vol 87 (1) ◽  
pp. 110-120 ◽  
Author(s):  
Julia R Khusnutdinova ◽  
Peter Y Zavalij ◽  
Andrei N Vedernikov
Keyword(s):  
Aqueous Solution ◽  
Aerobic Oxidation ◽  
Reductive Elimination ◽  
High Yield ◽  
Ambient Conditions ◽  
Activation Barriers ◽  
Methanol Solutions ◽  
Anionic Species ◽  
Mechanism Of Oxidation ◽  
Solution Mechanism

Oxidation of phenyl PtII complexes K[(dpms)PtIIPh2], 1, (dpms)PtIIPh(MeOH), 2, (dpms)PtIIPh(OH2), 3, and methyl PtII complex (dpms)PtIIMe(NH2Ph), 6, with O2 in aqueous or methanol solutions under ambient conditions leads to corresponding (dpms)PtIVR(X)OH complexes (R = X = Ph, 7; R = Ph, X = OH, 8; R = Ph, X = OMe, 9; R = Me, X = NHPh; 11; dpms = di(2-pyridyl)methanesulfonate). Complexes 7–9 could be isolated in high yield. Complex 11 as well as its phenyl analogue (dpms)PtIVPh(NHPh)OH, 10 can be prepared in high yield by oxidation of corresponding (dpms)PtIIR(NH2Ph) with H2O2 in methanol. Phenyl PtII complexes (dpms)PtIIPh(HX) derived from HX = aniline and DMSO, 4 and 5, respectively, are inert toward O2. The rate of oxidation of 1–5 with O2 decreases in the order 1 > 3 ~ 2 » 4, and 5 is unreactive. Methyl analogues are significantly more reactive compared with their phenyl counterparts. Proposed mechanism of oxidation with O2 includes formation of anionic species (dpms)PtIIR(X)– responsible for reaction with dioxygen. Attempts at C–O and C–N reductive elimination from phenyl PtIV complexes 7–10 do not lead to phenyl derivatives PhX at 80–100 °C, consistent with the results of the DFT estimates of corresponding activation barriers, ΔG0 exceeding 28 kcal/mol.Key words: platinum phenyl complexes, oxidation, dioxygen, aqueous solution, mechanism.

Chemical transformations of glucose to value added products using Cu-based catalytic systems

2013 ◽  
Vol 15 (29) ◽  
pp. 12165 ◽  
Author(s):  
Alfonso Yepez ◽  
Antonio Pineda ◽  
Angel Garcia ◽  
Antonio A. Romero ◽  
Rafael Luque
Keyword(s):  
Value Added ◽  
Chemical Transformations ◽  
Catalytic Systems ◽  
Value Added Products

Fluoroalkyl phthalocyanines: Bioinspired catalytic materials

2018 ◽  
Vol 22 (05) ◽  
pp. 371-397 ◽  
Author(s):  
Erik N. Carrión ◽  
Andrei Loas ◽  
Hemantbhai H. Patel ◽  
Marius Pelmuş ◽  
Karpagavalli Ramji ◽  
...  
Keyword(s):  
Transition Metal Complexes ◽  
Organic Molecules ◽  
Aerobic Oxidation ◽  
Biological Significance ◽  
Reaction Parameters ◽  
New Class ◽  
Catalytic Materials ◽  
Oxidation Resistant ◽  
Theranostic Applications ◽  
Analytical Device

The design of self oxidation-resistant catalytic materials based on organic molecules, although advantageous due to the ability to control their structures, is limited by the presence of labile C–H bonds. This mini review summarizes recent work aimed at first-row transition metal complexes of a new class of coordinating ligands, fluoroalkyl-substituted fluorophthalocyanines, R[Formula: see text]Pcs, ligands in which all, or the majority of their C–H bonds are replaced by a combination of fluoro- and perfluoroalkyl groups yielding porphyrin-bioinspired catalyst models. In the case of homogeneous systems, cobalt(II) complexes catalyze the aerobic oxidation of thiols to disulfides, a reaction of both biological significance and industrial importance. Zinc(II) complexes photo-generate excited state singlet oxygen, [Formula: see text]O[Formula: see text], resulting in both the incorporation of O[Formula: see text] in C–H bonds or, depending on the reaction parameters, oxidation of dyes, model pollutants. Catalyst heterogenization using oxidic and other supports yields stable, active hybrid materials. Functionalized R[Formula: see text]Pcs with acidic (–COOH) or basic (–NH[Formula: see text]R[Formula: see text], [Formula: see text] 2) groups exhibit scaffolds that afford both conjugation with biological vectors for theranostic applications as well as solid-supported materials with superior stability. Electrodes modified with hybrid R[Formula: see text]Pc-containing supports have also been used in photo-oxidations, replacing enzymes and H[Formula: see text]O[Formula: see text] associated reagents with a combination of light and air. An analytical device employed for the nano-level detection of environmentally deleterious antibiotics has been constructed.

Recovery of Nickel and Zinc Using Biogenerated Sulphuric Acid

2009 ◽  
Vol 71-73 ◽  
pp. 649-652 ◽  
Author(s):  
Nadia Yagnentkovsky ◽  
M. Viera ◽  
Edgardo R. Donati
Keyword(s):  
Sulphuric Acid ◽  
Ph Value ◽  
Aerobic Oxidation ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Sulphuric Acid Solution ◽  
Pulp Density ◽  
Solid Matrix ◽  
Attractive Alternative ◽  
Acidithiobacillus Thiooxidans

Sludge generated in automotive and related industries often contains heavy metals. Bioleaching is an attractive alternative for the treatment of metal containing solids. Bacteria of the genus Acidithiobacillus are the most important microorganisms applied to metal solubilisation. These microorganisms are able to produce sulphuric acid from the aerobic oxidation of elemental sulphur. The biogenerated sulphuric acid can be applied to the solubilisation of metals from a solid matrix. In this paper we present the results of our experiments aimed at the removal of nickel and zinc from sludge generated in the water treatment plant of an automotive industry. Acidithiobacillus thiooxidans cells were immobilised on sulphur pearls in a column reactor. The effects of sulphur pulp density and the dilution rate on the production of sulphuric acid were studied. In a second stage, sulphuric acid was used to solubilise the nickel and zinc from the sludge. The effects of different sludge pulp densities and initial acid pH were studied. High recoveries of zinc and nickel were obtained when the pH value of the sulphuric acid solution was lower than 2.0 for 1 and 2 % of pulp density.

scholarly journals A Bio-Inspired Lanthanum-Ortho Quinone Catalyst for Aerobic Oxidation of Alcohol

2020 ◽  
Author(s):  
Ruipu Zhang ◽  
Long Zhang ◽  
Ming-Tian Zhang ◽  
Sanzhong Luo
Keyword(s):  
Aerobic Oxidation ◽  
Earth Metal ◽  
Open Shell ◽  
Oxidation Catalysis ◽  
Oxidation Catalyst ◽  
Oxidation Reactions ◽  
Reductive Activation ◽  
Ambient Conditions ◽  
Semiquinone Radicals ◽  
Oxidation Of Alcohols

<p>Oxidation reactions are fundamental transformations in organic synthesis and chemical industry. With oxygen or air as terminal oxidant, aerobic oxidation catalysis provides the most sustainable and economic oxidation processes. Most aerobic oxidation catalysis employs redox metal as its active center. While nature provides non-redox metal strategy as in pyrroloquinoline quinone (PQQ)-dependent methanol dehydrogenases (MDH), such an effective chemical version is unknown. Inspired by the recently discovered rare earth metal-dependent enzyme Ln-MDH, here we show that an open-shell semi-quinone anionic radical species in complexing with lanthanum could serve as a very efficient aerobic oxidation catalyst under ambient conditions. In this catalyst, the lanthanum metal serves only as a Lewis acid promoter and the redox process occurs exclusively on the semiquinone ligand. The catalysis is initiated by 1e<sup>-</sup>-reduction of lanthanum-activated <i>ortho</i>-quinone to a semiquinone-lanthanum complex La(<b>SQ<sup>-.</sup></b>)<sub>2</sub>, which undergoes a coupled O-H/C-H dehydrogenation for aerobic oxidation of alcohols with up to 330 h<sup>-1</sup> TOF. This study suggests a possible functional mode of semiquinone radicals, widely observed with quinoproteins in Nature. Moreover, this unique reductive activation strategy as well as the resulted radical anion as redox ligand creates a new turning point in the development of efficient aerobic oxidation catalysis.</p>

scholarly journals A Decade of Successful Collaborations in Nutritional Compound Process Research and Development

2021 ◽  
Vol 75 (11) ◽  
pp. 957-966
Author(s):  
Werner Bonrath ◽  
Roman Goy ◽  
Ulla Létinois ◽  
Marc-André Müller ◽  
Thomas Netscher ◽  
...  
Keyword(s):  
Research And Development ◽  
Chemical Processes ◽  
Process Research ◽  
Development Projects ◽  
Chemical Transformations ◽  
Academic Institutions ◽  
Catalytic Systems ◽  
The Past ◽  
Compound Process ◽  
Synthetic Routes

Collaborations between academia and industry are vital for modern industrial research and development projects, combining the best of both worlds to develop sustainable chemical processes. Herein we summarize a number of successful cooperations between DSM Nutritional Products and Swiss academic institutions that have been carried out over approximately the past decade. A wide variety of reactions and processes have been investigated with experts located in Switzerland. New synthetic routes, chemical transformations and reactor concepts have been developed to produce industrially relevant compounds. Additionally the scope of known catalytic systems has been probed and new catalysts showing improved selectivity have been designed, synthesized and tested. We describe how the research was supported by DSM, the parallel in-house investigations and also how the projects were continued and further developed.

The selective monobromination of a highly sterically encumbered corrole: Structural and spectroscopic properties of Fe(Cl)(2-bromo-5,10,15-tris(triphenyl)phenyl corrole)

2021 ◽  
pp. A-J
Author(s):  
Jessica G. Alvarado ◽  
Daniel C. Cummins ◽  
Andrada C. Diaconescu ◽  
Maxime A. Siegler ◽  
David P. Goldberg
Keyword(s):  
Cyclic Voltammetry ◽  
Complex Analysis ◽  
Spectroscopic Properties ◽  
Chloride Complex ◽  
Iron Chloride ◽  
Mossbauer Spectrum ◽  
Chemical Transformations ◽  
Catalytic Systems ◽  
High Yields

The corrole ligand serves as a versatile tri-anionic, macrocyclic platform on which to model biological catalytic systems, as well as to effect mechanistically challenging chemical transformations. Herein we describe the synthesis, structure, and characterization of an isomerically pure corrole ligand, selectively mono-brominated at the β-carbon position adjacent to the corrole C-C bond (2-C) and produced in relatively high yields, as well as its iron chloride complex. Analysis of the iron metalated complex by cyclic voltammetry shows that the bromine being present on the ligand resulted in anodic shifts of +93 and +63 mV for first oxidation and first reduction of the complex respectively. The Mössbauer spectrum of the iron metalated complex shows negligible change relative to the non-brominated analog, indicating the presence of the halide substituent predominantly effects the orbitals of the ligand rather than the metal.

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