Bioinspired catalytic reactions with vitamin B12 derivative and photosensitizers

2013 ◽  
Vol 85 (7) ◽  
pp. 1415-1426 ◽  
Author(s):  
Yoshio Hisaeda ◽  
Keishiro Tahara ◽  
Hisashi Shimakoshi ◽  
Takahiro Masuko
Keyword(s):  
Titanium Dioxide ◽  
Human Serum Albumin ◽  
Green Chemistry ◽  
Catalytic Reactions ◽  
Vitamin B ◽  
Hybrid Catalyst ◽  
Combined System ◽  
Catalytic Systems ◽  
Radical Intermediates ◽  
Ru Complex

As part of a study directed toward design of good catalytic systems based upon a hydrophobic vitamin B12, heptamethyl cobyrinate perchlorate, we describe the preparation of various nanomaterials using the vitamin B12 derivative and photosensitizers. Examples include vitamin B12-hyperbranched polymers (HBPs), human serum albumin (HSA) containing vitamin B12 derivatives, a vitamin B12-titanium dioxide hybrid catalyst, a vitamin B12-Ru complex combined system, and a vitamin B12-rose bengal combined system. These bioinspired materials have the potential as catalytic systems for the degradation of organic halide pollutants and for molecular transformations via radical intermediates during irradiation by UV or visible light, and offer a variety of applications that are of great interest in terms of green chemistry.

scholarly journals Learning from B12 enzymes: biomimetic and bioinspired catalysts for eco-friendly organic synthesis

2018 ◽  
Vol 14 ◽  
pp. 2553-2567 ◽  
Author(s):  
Keishiro Tahara ◽  
Ling Pan ◽  
Toshikazu Ono ◽  
Yoshio Hisaeda
Keyword(s):  
Organic Synthesis ◽  
Reaction Mechanisms ◽  
Catalytic Reactions ◽  
Vitamin B ◽  
Catalytic Systems ◽  
New Approach ◽  
Enzyme Functions

Cobalamins (B12) play various important roles in vivo. Most B12-dependent enzymes are divided into three main subfamilies: adenosylcobalamin-dependent isomerases, methylcobalamin-dependent methyltransferases, and dehalogenases. Mimicking these B12 enzyme functions under non-enzymatic conditions offers good understanding of their elaborate reaction mechanisms. Furthermore, bio-inspiration offers a new approach to catalytic design for green and eco-friendly molecular transformations. As part of a study based on vitamin B12 derivatives including heptamethyl cobyrinate perchlorate, we describe biomimetic and bioinspired catalytic reactions with B12 enzyme functions. The reactions are classified according to the corresponding three B12 enzyme subfamilies, with a focus on our recent development on electrochemical and photochemical catalytic systems. Other important reactions are also described, with a focus on radical-involved reactions in terms of organic synthesis.

Chiral imidazolidinones: A class of priviliged organocatalysts in stereoselective organic synthesis

2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Laura Raimondi ◽  
Chiara Faverio ◽  
Monica Fiorenza Boselli
Keyword(s):  
Pharmaceutical Industry ◽  
Green Chemistry ◽  
Organic Synthesis ◽  
Catalytic Synthesis ◽  
Biological Chemistry ◽  
Chiral Molecules ◽  
Catalytic Systems ◽  
Drug Synthesis ◽  
Industry Needs

AbstractChiral molecules hold a mail position in Organic and Biological Chemistry, so pharmaceutical industry needs suitable strategies for drug synthesis. Moreover, Green Chemistry procedures are increasingly required in order to avoid environment deterioration. Catalytic synthesis, in particular organocatalysis, in thus a continuously expanding field. A survey of more recent researches involving chiral imidazolidinones is here presented, with a particular focus on immobilized catalytic systems.

Photo-electrochemical and photo-catalytic reactions of pigmentary titanium dioxide

1979 ◽  
Vol 75 (0) ◽  
pp. 2517
Author(s):  
Hugh H. Chambers ◽  
R. Stephen Davidson ◽  
Ralph R. Meek ◽  
Richard M. Slater
Keyword(s):  
Titanium Dioxide ◽  
Catalytic Reactions

scholarly journals Spectroscopic Study of the Interactions of Ruthenium-Ketoconazole Complexes of Known Antiparasitic Activity with Human Serum Albumin and Apotransferrin

2017 ◽  
Vol 57 (3) ◽  
Author(s):  
Jesús G. Estrada ◽  
Roberto A. Sánchez-Delgado
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Leishmania Major ◽  
Tryptophan Fluorescence ◽  
Ru Complex ◽  
Complex Protein ◽  
Number Of Binding Sites ◽  
Antiparasitic Drugs ◽  
Static Mechanism

The pharmacological properties of any drug are related to its ability to interact with macromolecular blood components. The interaction of human serum albumin (HSA) and apotransferrin (ATf) with six Ru<sup>II</sup> complexes containing ketoconazole (KTZ), which we have previously reported to be active against <em>Leishmania major</em> and <em>Trypanosoma cruzi</em>, has been investigated by monitoring the tryptophan fluorescence intensity of each protein upon incremental addition of the complexes. All the Ru-KTZ derivatives, namely <em>cis</em>-<em>fac</em>-[Ru<sup>II</sup>Cl<sub>2</sub>(DMSO)<sub>3</sub>(KTZ)] (<strong>1</strong>), <em>cis</em>-[Ru<sup>II</sup>Cl<sub>2</sub>(bipy)(DMSO)(KTZ)] (<strong>2</strong>), [Ru<sup>II</sup>(η6-<em>p</em>-cymene)Cl<sub>2</sub>(KTZ)] (<strong>3</strong>), [Ru<sup>II</sup>(η<sup>6</sup>-<em>p</em>-cymene)(en)(KTZ)][BF<sub>4</sub>]<sub>2</sub> (<strong>4</strong>), [Ru<sup>II</sup>(η<sup>6</sup>-<em>p</em>-cymene)(bipy)(KTZ)][BF<sub>4</sub>]<sub>2</sub> (<strong>5</strong>), and [Ru<sup>II</sup>(η<sup>6</sup>-<em>p</em>-cymene)(acac)(KTZ)][BF<sub>4</sub>] (<strong>6</strong>) are able to quench the intrinsic fluorescence of HSA and ATf at 27 ºC. Analysis of the spectroscopic data using Stern-Volmer plots indicates that in both cases the quenching takes place principally through a static mechanism involving the formation of Ru complex-protein adducts; further analysis of the fluorescence data allowed the estimation of apparent association constants and the number of binding sites for each protein and each compound. The results indicate that both HSA and ATf are possible effective transporters for Ru-KTZ antiparasitic drugs.

scholarly journals Plasmon-Induced Electrocatalysis with Multi-Component Nanostructures

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 43 ◽  
Author(s):  
Palaniappan Subramanian ◽  
Dalila Meziane ◽  
Robert Wojcieszak ◽  
Franck Dumeignil ◽  
Rabah Boukherroub ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Charge Carriers ◽  
Catalytic Reactions ◽  
Synthetic Methods ◽  
Metal Nanostructures ◽  
Electron Hole ◽  
Catalytic Systems ◽  
Electrochemical Catalysis ◽  
Electrochemically Active ◽  
Shed Light

Noble metal nanostructures are exceptional light absorbing systems, in which electron–hole pairs can be formed and used as “hot” charge carriers for catalytic applications. The main goal of the emerging field of plasmon-induced catalysis is to design a novel way of finely tuning the activity and selectivity of heterogeneous catalysts. The designed strategies for the preparation of plasmonic nanomaterials for catalytic systems are highly crucial to achieve improvement in the performance of targeted catalytic reactions and processes. While there is a growing number of composite materials for photochemical processes-mediated by hot charge carriers, the reports on plasmon-enhanced electrochemical catalysis and their investigated reactions are still scarce. This review provides a brief overview of the current understanding of the charge flow within plasmon-enhanced electrochemically active nanostructures and their synthetic methods. It is intended to shed light on the recent progress achieved in the synthesis of multi-component nanostructures, in particular for the plasmon-mediated electrocatalysis of major fuel-forming and fuel cell reactions.

One-Pot Synthesis of Imines from Nitroaromatics and Alcohols by Tandem Photocatalytic and Catalytic Reactions on Degussa (Evonik) P25 Titanium Dioxide

2015 ◽  
Vol 7 (6) ◽  
pp. 3797-3806 ◽  
Author(s):  
Hiroaki Hirakawa ◽  
Miyu Katayama ◽  
Yasuhiro Shiraishi ◽  
Hirokatsu Sakamoto ◽  
Kunlei Wang ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Catalytic Reactions ◽  
One Pot ◽  
One Pot Synthesis

Ultrasound-Promoted Organic Synthesis – A Recent Update

2021 ◽  
Vol 25 ◽  
Author(s):  
Goutam Brahmachari ◽  
Nayana Nayek ◽  
Mullicka Mandal ◽  
Anindita Bhowmick ◽  
Indrajit Karmakar
Keyword(s):  
Organic Chemistry ◽  
Green Chemistry ◽  
Organic Synthesis ◽  
Ultrasound Irradiation ◽  
Present Review ◽  
Organic Transformations ◽  
Reaction Conditions ◽  
Catalytic Systems ◽  
Bond Forming ◽  
Reducing Energy

: Ultrasonication, nowadays, is well-regarded as an effective green tool in implementing a plethora of organic transformations. The last decade has seen quite useful applications of ultrasound irradiation in synthetic organic chemistry. Ultrasound has already come out as a unique technique in green chemistry practice, for its inherent properties of minimizing wastes and reducing energy and time, thereby increasing the product yields with higher purities under milder reaction conditions. The present review summarizes ultrasound-promoted useful organic transformations involving both carbon-carbon and carbon-heteroatom (N, O, S) bond-forming reactions in the absence or presence of varying catalytic systems, reported during the period 2016-2020.

Application of catalytic adsorptive stripping voltammetry in water analysis

2001 ◽  
Vol 1 (2) ◽  
pp. 1-8 ◽  
Author(s):  
A. Bobrowski ◽  
J. Zarebski
Keyword(s):  
Stripping Voltammetry ◽  
Catalytic Reactions ◽  
Organic Substances ◽  
Considerable Decrease ◽  
Ultratrace Analysis ◽  
Catalytic Systems ◽  
Analytical Response ◽  
Trace Elements In Water ◽  
Electroactive Species

The application of catalytic adsorptive striping voltammetry (CAdSV) for the determination of the trace elements in water is presented. The CAdSV, coupling of very efficient adsorptive accumulation of the electroactive species on the electrode surface with the catalytic reaction, provides a significant amplification of the analytical response, and consequently a considerable decrease of the detection limit, as well as an improvement of the selectivity of the determination. The course of the catalytic reactions occurring in catalytic systems, which is most frequently applied in CAdSV analysis, is given. The features and advantages of the CAdSV method and its exploitation in ultratrace analysis of water samples are discussed. Numerous examples of the CAdSV systems, which have found application in the determination of Co, Cr, U, Fe, Mo, Pt, Rh, Ti, W and V, as well as of some anions and organic substances in various kinds of water, are listed.

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