scholarly journals Application of visible-light photosensitization to form alkyl-radical-derived thin films on gold

2017 ◽  
Vol 8 ◽  
pp. 1863-1877 ◽  
Author(s):  
Rashanique D Quarels ◽  
Xianglin Zhai ◽  
Neepa Kuruppu ◽  
Jenny K Hedlund ◽  
Ashley A Ellsworth ◽  
...  
Keyword(s):  
Thin Films ◽  
Visible Light ◽  
Alkyl Radical ◽  
Organic Molecules ◽  
Film Structure ◽  
Small Organic Molecules ◽  
Alkyl Radicals ◽  
Mild Conditions ◽  
Radical Generation ◽  
First Time

Visible-light irradiation of phthalimide esters in the presence of the photosensitizer [Ru(bpy)3]2+ and the stoichiometric reducing agent benzyl nicotinamide results in the formation of alkyl radicals under mild conditions. This approach to radical generation has proven useful for the synthesis of small organic molecules. Herein, we demonstrate for the first time the visible-light photosensitized deposition of robust alkyl thin films on Au surfaces using phthalimide esters as the alkyl radical precursors. In particular, we combine visible-light photosensitization with particle lithography to produce nanostructured thin films, the thickness of which can be measured easily using AFM cursor profiles. Analysis with AFM demonstrated that the films are robust and resistant to mechanical force while contact angle goniometry suggests a multilayered and disordered film structure. Analysis with IRRAS, XPS, and TOF SIMS provides further insights.

Visible-Light Photosensitized Aryl and Alkyl Decarboxylative Carbon-Heteroatom and Carbon-Carbon Bond Formations

2019 ◽  
Author(s):  
Tuhin Patra ◽  
Satobhisha Mukherjee ◽  
Jiajia Ma ◽  
Felix Strieth-Kalthoff ◽  
Frank Glorius
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Alkyl Radical ◽  
General Strategy ◽  
Alkyl Radicals ◽  
Bond Forming ◽  
Radical Trapping ◽  
Carbon Carbon Bond ◽  
Radical Generation ◽  
Trapping Agent

<sub>A general strategy to access both aryl and alkyl radicals by photosensitized decarboxylation of the corresponding carboxylic acids esters has been developed. An energy transfer mediated homolysis of unsymmetrical sigma-bonds for a concerted fragmentation/decarboxylation process is involved. As a result, an independent aryl/alkyl radical generation step enables a series of key C-X and C-C bond forming reactions by simply changing the radical trapping agent.</sub>

Visible-Light Photosensitized Aryl and Alkyl Decarboxylative Carbon-Heteroatom and Carbon-Carbon Bond Formations

2019 ◽  
Author(s):  
Frank Glorius ◽  
Tuhin Patra ◽  
Satobhisha Mukherjee ◽  
Jiajia Ma ◽  
Felix Strieth-Kalthoff
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Alkyl Radical ◽  
General Strategy ◽  
Alkyl Radicals ◽  
Bond Forming ◽  
Radical Trapping ◽  
Carbon Carbon Bond ◽  
Radical Generation ◽  
Trapping Agent

<sub>A general strategy to access both aryl and alkyl radicals by photosensitized decarboxylation of the corresponding carboxylic acids esters has been developed. An energy transfer mediated homolysis of unsymmetrical sigma-bonds for a concerted fragmentation/decarboxylation process is involved. As a result, an independent aryl/alkyl radical generation step enables a series of key C-X and C-C bond forming reactions by simply changing the radical trapping agent.</sub>

Visible-Light Photosensitized Aryl and Alkyl Decarboxylative Carbon-Heteroatom and Carbon-Carbon Bond Formations

2019 ◽  
Author(s):  
Frank Glorius ◽  
Tuhin Patra ◽  
Satobhisha Mukherjee ◽  
Jiajia Ma ◽  
Felix Strieth-Kalthoff
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Alkyl Radical ◽  
General Strategy ◽  
Alkyl Radicals ◽  
Bond Forming ◽  
Radical Trapping ◽  
Carbon Carbon Bond ◽  
Radical Generation ◽  
Trapping Agent

<sub>A general strategy to access both aryl and alkyl radicals by photosensitized decarboxylation of the corresponding carboxylic acids esters has been developed. An energy transfer mediated homolysis of unsymmetrical sigma-bonds for a concerted fragmentation/decarboxylation process is involved. As a result, an independent aryl/alkyl radical generation step enables a series of key C-X and C-C bond forming reactions by simply changing the radical trapping agent.</sub>

Nitroacenaphthene as a New Photocatalyst for the Synthesis of Sulfonyl Amidines

Synthesis ◽  
2019 ◽  
Vol 51 (23) ◽  
pp. 4425-4433
Author(s):  
Yong Jian ◽  
Ming Chen ◽  
Chao Yang ◽  
Wujiong Xia
Keyword(s):  
Visible Light ◽  
Small Molecule ◽  
Reaction Pathways ◽  
Visible Light Photocatalyst ◽  
Mild Conditions ◽  
Sulfonyl Azides ◽  
Site Selective ◽  
First Time

A small molecule, namely nitroacenaphthene, is reported for the first time as a recyclable visible-light photocatalyst for the construction of the C=N bond from sulfonyl azides and amines. This scalable, site-selective protocol provides a convenient way to access various sulfonyl amidines under mild conditions. Two reaction pathways are proposed, according to different transformation patterns.

PERSISTENT PHOTOCONDUCTIVITY IN La0.7CaxBa1-xMnO3 THIN FILMS

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3786-3791 ◽  
Author(s):  
R. CAURO ◽  
J. C. GRENET ◽  
A. GILABERT ◽  
M. G. MEDICI
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Visible Light ◽  
Low Temperatures ◽  
Transport Mechanism ◽  
Persistent Photoconductivity ◽  
Temperature Range ◽  
Insulator Metal Transition ◽  
First Time

We report, for the first time, experiments of persistent photoconductivity (PPC) in thin films of manganese perovskites La 0.7 Ca 0.25 Ba 0.05 MnO 3 and La 0.7 Ca 0.2 Ba 0.1 MnO 3 showing a persistent decrease of a few percent of the resistance after illumination with visible light. These persistent photoinduced effects are seen only in a range of low temperatures (<25 K) well below the insulator-metal transition at respectively T c=173 K and T c=120 K. In this low temperature range, the transport mechanism is rather of activated hopping type regime.

scholarly journals Method for measurement of the density of thin films of small organic molecules

2007 ◽  
Vol 78 (3) ◽  
pp. 034104 ◽  
Author(s):  
Hai-Feng Xiang ◽  
Zong-Xiang Xu ◽  
V. A. L. Roy ◽  
Chi-Ming Che ◽  
P. T. Lai
Keyword(s):  
Thin Films ◽  
Organic Molecules ◽  
Small Organic Molecules

scholarly journals Tuning of catalytic properties for electrooxidation of small organic molecules on Pt-based thin films via controlled thermal treatment

2019 ◽  
Vol 371 ◽  
pp. 96-105 ◽  
Author(s):  
D.V. Tripković ◽  
K.Dj. Popović ◽  
V.M. Jovanović ◽  
J.A. Nogueira ◽  
H. Varela ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Treatment ◽  
Organic Molecules ◽  
Catalytic Properties ◽  
Small Organic Molecules

Hydrogel supported chiral imidazolidinone for organocatalytic enantioselective reduction of olefins in water

2016 ◽  
Vol 70 (4) ◽  
Author(s):  
Alessandro Sacchetti ◽  
Filippo Rossi ◽  
Arianna Rossetti ◽  
Roberto Pesa ◽  
Emanuele Mauri
Keyword(s):  
Asymmetric Synthesis ◽  
Asymmetric Catalysis ◽  
Medicinal Chemistry ◽  
Organic Molecules ◽  
Biological Properties ◽  
Good Activity ◽  
Small Organic Molecules ◽  
Enantioselective Reduction ◽  
Activated Olefins ◽  
First Time

AbstractChiral products play an important role particularly in the field of medicinal chemistry, where it is known that enantiomers often have very different biological properties and effects. One of the most powerful tool to obtain a product as a single enantiomer is asymmetric catalysis. Recently, organocatalysis, i.e. the use of small organic molecules to catalyze enantioselective transformations, has emerged as a prominent field in asymmetric synthesis. In this work, the use of hydrogels as a support for a chiral imidazolidinone organocatalyst (MacMillan catalyst) and its application in the reduction of activated olefins mediated by the Hantzsch ester is reported for the first time. Results showed a good activity of hydrogels in respect to both yield and enantioselection.

scholarly journals Catalytic enantioselective reductive domino alkyl arylation of acrylates via nickel/photoredox catalysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pengcheng Qian ◽  
Haixing Guan ◽  
Yan-En Wang ◽  
Qianqian Lu ◽  
Fan Zhang ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Visible Light ◽  
Nickel Catalyst ◽  
Alkyl Radical ◽  
Reductive Elimination ◽  
Important Class ◽  
Organometallic Reagents ◽  
Mild Conditions ◽  
Key Steps ◽  
Carbonyl Radical

AbstractNonsteroidal anti-inflammatory drug derivatives (NSAIDs) are an important class of medications. Here we show a visible-light-promoted photoredox/nickel catalyzed approach to construct enantioenriched NSAIDs via a three-component alkyl arylation of acrylates. This reductive cross-electrophile coupling avoids preformed organometallic reagents and replaces stoichiometric metal reductants by an organic reductant (Hantzsch ester). A broad range of functional groups are well-tolerated under mild conditions with high enantioselectivities (up to 93% ee) and good yields (up to 90%). A study of the reaction mechanism, as well as literature precedence, enabled a working reaction mechanism to be presented. Key steps include a reduction of the alkyl bromide to the radical, Giese addition of the alkyl radical to the acrylate and capture of the α-carbonyl radical by the enantioenriched nickel catalyst. Reductive elimination from the proposed Ni(III) intermediate generates the product and forms Ni(I).

scholarly journals Emodin as a novel organic photocatalyst for selective oxidation of sulfides under mild conditions

RSC Advances ◽  
2020 ◽  
Vol 10 (34) ◽  
pp. 19747-19750
Author(s):  
Yan Zhang ◽  
Jiangli Lou ◽  
Min Li ◽  
Zhenbo Yuan ◽  
Yijian Rao
Keyword(s):  
Visible Light ◽  
Selective Oxidation ◽  
Mild Conditions ◽  
Oxidation Of Sulfides ◽  
Naturally Occurring ◽  
First Time

Naturally-occurring Emodin was successfully employed in the selective oxidation of sulfides promoted by visible-light as a novel organic photocatalyst for the first time.

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