Post-Synthetic Functionalization of Tryptophan Protected Peptides Sequences through Indole (C-2) Photocatalytic Alkylation

2021 ◽  
Author(s):  
Marcio Weber Paixao ◽  
Rafaely Nascimento Lima ◽  
José Antonio Campos Delgado ◽  
Darlon I. Bernardi ◽  
Roberto Berlinck ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Carbonyl Compounds ◽  
Light Irradiation ◽  
Protected Peptides

We report a selective, mild, and efficient C-H functionalization of tryptophan and of tryptophan-containing peptides with activated α-bromo-carbonyl compounds under visible-light irradiation. The protocol is valued by the wide substrate...

Visible photostability of some ruthenium and platinum phthalocyanines in water and in the presence of organic substrates

2010 ◽  
Vol 14 (06) ◽  
pp. 499-508 ◽  
Author(s):  
Manuela Carchesio ◽  
Lucia Tonucci ◽  
Nicola d'Alessandro ◽  
Antonino Morvillo ◽  
Piero Del Boccio ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Carbonyl Compounds ◽  
Furfuryl Alcohol ◽  
Phenylacetic Acid ◽  
Water Soluble ◽  
Light Irradiation ◽  
Organic Substrates ◽  
Visible Spectra ◽  
Trapping Agent

Water-soluble, metal-tetrasubstituted phthalocyanines ( -SO3H , MPcS and -COOH , MPcC) of platinum and ruthenium were synthesized and their photostability to visible light irradiation was determined. For the ruthenium phthalocyanines, the characteristic visible Q band of the phthalocyanines was almost totally suppressed after five days of irradiation. The platinum derivatives were instead more resistant to photodegradation, and the Q band did not decrease by more than 25%. The addition of carbonyl compounds to the phthalocyanine solution in water (at concentrations at least 1400-fold those of the phthalocyanines) dramatically accelerated the photobleaching of these phthalocyanine complexes. PtPcS turned from blue to green and to colorless with one day of visible-light irradiation in the presence of acetone. This effect decreased with the increase in molecular weight of the ketones (from acetone to 2-pentanone). The addition of alcohols (i.e. 1-butanol) or other organics (i.e. phenylacetic acid) did not affect the photostability of these metal-tetrasubstituted phthalocyanines. Dioxygen also had an important role, as when the solutions of phthalocyanines were carefully deaerated before irradiation, the visible spectra were preserved. The platinum phthalocyanines, as with the palladium analogs, sensitize the photoproduction of 1O2 , as shown by the formation of endoperoxide and its rearranged products in the presence of furfuryl alcohol (a singlet oxygen trapping agent).

Oxidative alkylation of alkenes with carbonyl compounds through concomitant 1,2-aryl migration by photoredox catalysis

2020 ◽  
Vol 44 (37) ◽  
pp. 16031-16035
Author(s):  
Zhaowei Lin ◽  
Maojian Lu ◽  
Boyi Liu ◽  
Jing Gao ◽  
Mingqiang Huang ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Carbonyl Compounds ◽  
Light Irradiation ◽  
Photoredox Catalysis ◽  
Diaryliodonium Salt ◽  
Oxidative Alkylation ◽  
Organic Fluorophore

An efficient protocol for the construction of 1,5-diketones was realized in the presence of organic fluorophore 4CzIPN, diaryliodonium salt, and visible light irradiation.

scholarly journals Synthesis of nitrogen heterocycles via α-aminoalkyl radicals generated from α-silyl secondary amines under visible light irradiation

2014 ◽  
Vol 50 (64) ◽  
pp. 8900-8903 ◽  
Author(s):  
Kazunari Nakajima ◽  
Mai Kitagawa ◽  
Yuya Ashida ◽  
Yoshihiro Miyake ◽  
Yoshiaki Nishibayashi
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Carbonyl Compounds ◽  
Nitrogen Heterocycles ◽  
Light Irradiation ◽  
Secondary Amines ◽  
One Pot

We have succeeded in the visible light-mediated synthetic use of α-aminoalkyl radicals derived from α-silyl secondary amines toward addition to α,β-unsaturated carbonyl compounds. The resulting γ-aminocarbonyl compounds are converted into γ-lactams and pyrroles in a one-pot process.

Mesoporous (001)-TiO2 nanocrystals with tailored Ti3+ and surface oxygen vacancies for boosting photocatalytic selective conversion of aromatic alcohols

2021 ◽  
Vol 11 (8) ◽  
pp. 2939-2947
Author(s):  
Dianfeng Li ◽  
Jinguo Wang ◽  
Fengxia Xu ◽  
Nianchen Zhang ◽  
Yong Men
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Carbonyl Compounds ◽  
Oxygen Vacancies ◽  
Light Irradiation ◽  
Water Medium ◽  
Surface Oxygen ◽  
Tio2 Nanocrystals ◽  
Selective Conversion ◽  
Aromatic Alcohols

Mesoporous (001)-TiO2 nanocrystals with tailored Ti3+ and surface oxygen vacancies exhibited remarkably boosted photoactivity for selective conversion of aromatic alcohols to carbonyl compounds in water medium under visible-light irradiation.

Cu Doped TiO2: Visible Light Assisted Photocatalytic Antimicrobial Activity and High Temperature Anatase Stability

2018 ◽  
Author(s):  
Snehamol Mathew ◽  
Priyanka Ganguly ◽  
Stephen Rhatigan ◽  
Vignesh Kumaravel ◽  
Ciara Byrne ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Density Functional ◽  
Anatase Phase ◽  
Sol Gel ◽  
Chemical Properties ◽  
Light Irradiation ◽  
Health Concern ◽  
Bacterial Inactivation ◽  
X Ray

Indoor surface contamination by microbes is a major public health concern. A damp environment is one potential sources for microbe proliferation. Smart photocatalytic coatings on building surfaces using semiconductors like titania (TiO<sub>2</sub>) can effectively curb this growing threat.<b> </b>Metal-doped titania in anatase phase has been proved as a promising candidate for energy and environmental applications. In this present work, the antimicrobial efficacy of copper (Cu) doped TiO<sub>2 </sub>(Cu-TiO<sub>2</sub>) was evaluated against <i>Escherichia coli</i> (Gram-negative) and <i>Staphylococcus aureus</i> (Gram-positive) under visible light irradiation. Doping of a minute fraction of Cu (0.5 mol %) in TiO<sub>2 </sub>was carried out <i>via</i> sol-gel technique. Cu-TiO<sub>2</sub> further calcined at various temperatures (in the range of 500 °C – 700 °C) to evaluate the thermal stability of TiO<sub>2</sub> anatase phase. The physico-chemical properties of the samples were characterised through X-ray diffraction (XRD), Raman spectroscopy, X-ray photo-electron spectroscopy (XPS) and UV-visible spectroscopy techniques. XRD results revealed that the anatase phase of TiO<sub>2</sub> was maintained well, up to 650 °C, by the Cu dopant. UV-DRS results suggested that the visible light absorption property of Cu-TiO<sub>2 </sub>was enhanced and the band gap is reduced to 2.8 eV. Density functional theory (DFT) studies emphasises the introduction of Cu<sup>+</sup> and Cu<sup>2+</sup> ions by replacing Ti<sup>4+</sup> ions in the TiO<sub>2</sub> lattice, creating oxygen vacancies. These further promoted the photocatalytic efficiency. A significantly high bacterial inactivation (99.9%) was attained in 30 mins of visible light irradiation by Cu-TiO<sub>2</sub>.

Semiconductor Photocatalysts for Solar-to-Hydrogen Energy Conversion: Recent Advances of CdS

2020 ◽  
Vol 16 ◽  
Author(s):  
Yuxue Wei ◽  
Honglin Qin ◽  
Jinxin Deng ◽  
Xiaomeng Cheng ◽  
Mengdie Cai ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Visible Light ◽  
Hydrogen Evolution ◽  
Water Splitting ◽  
Visible Light Irradiation ◽  
Noble Metals ◽  
Light Irradiation ◽  
Photocatalytic Hydrogen Evolution ◽  
Theoretical Design ◽  
Recent Developments

Introduction: Solar-driven photocatalytic hydrogen production from water splitting is one of the most promising solutions to satisfy the increasing demands of a rapidly developing society. CdS has emerged as a representative semiconductor photocatalyst due to its suitable band gap and band position. However, the poor stability and rapid charge recombination of CdS restrict its application for hydrogen production. The strategy of using a cocatalyst is typically recognized as an effective approach for improving the activity, stability, and selectivity of photocatalysts. In this review, recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation are summarized. In particular, the factors affecting the photocatalytic performance and new cocatalyst design, as well as the general classification of cocatalysts, are discussed, which includes a single cocatalyst containing noble-metal cocatalysts, non-noble metals, metal-complex cocatalysts, metal-free cocatalysts, and multi-cocatalysts. Finally, future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are described. Background: Photocatalytic hydrogen evolution from water splitting using photocatalyst semiconductors is one of the most promising solutions to satisfy the increasing demands of a rapidly developing society. CdS has emerged as a representative semiconductor photocatalyst due to its suitable band gap and band position. However, the poor stability and rapid charge recombination of CdS restrict its application for hydrogen production. The strategy of using a cocatalyst is typically recognized as an effective approach for improving the activity, stability, and selectivity of photocatalysts. Methods: This review summarizes the recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation. Results: Recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation are summarized. The factors affecting the photocatalytic performance and new cocatalyst design, as well as the general classification of cocatalysts, are discussed, which includes a single cocatalyst containing noble-metal cocatalysts, non-noble metals, metal-complex cocatalysts, metal-free cocatalysts, and multi-cocatalysts. Finally, future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are described. Conclusion: The state-of-the-art CdS for producing hydrogen from photocatalytic water splitting under visible light is discussed. The future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are also described.

Spatial separation of dual-cocatalysts on bismuth vanadate for selective aerobic oxidation of benzylalcohols to benzaldehydes under visible light irradiation

2018 ◽  
Vol 8 (23) ◽  
pp. 6173-6179 ◽  
Author(s):  
Xu Jin ◽  
Rengui Li ◽  
Yue Zhao ◽  
Xiaodan Liu ◽  
Xiaoqi Wang ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Aerobic Oxidation ◽  
Spatial Separation ◽  
Bismuth Vanadate ◽  
Light Irradiation ◽  
Selective Aerobic Oxidation

Efficient converting of alcohols to aldehydes under visible light can be achieved on BiVO4 crystals with spatial separation of dual-cocatalysts.

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