Mechanism and Site Selectivity in Visible-Light Photocatalyzed C–H Functionalization: Insights from DFT Calculations

2016 ◽  
Vol 81 (16) ◽  
pp. 7110-7120 ◽  
Author(s):  
Taye B. Demissie ◽  
Jørn H. Hansen
Keyword(s):  
Dft Calculations ◽  
Visible Light ◽  
Site Selectivity

scholarly journals Fluorinated azobenzenes as supramolecular halogen-bonding building blocks

2019 ◽  
Vol 15 ◽  
pp. 2013-2019 ◽  
Author(s):  
Esther Nieland ◽  
Oliver Weingart ◽  
Bernd M Schmidt
Keyword(s):  
Solid State ◽  
Dft Calculations ◽  
Visible Light ◽  
Half Life ◽  
Photophysical Properties ◽  
Bathochromic Shift ◽  
Halogen Bonding ◽  
Building Blocks ◽  
Partial Overlap

ortho-Fluoroazobenzenes are a remarkable example of bistable photoswitches, addressable by visible light. Symmetrical, highly fluorinated azobenzenes bearing an iodine substituent in para-position were shown to be suitable supramolecular building blocks both in solution and in the solid state in combination with neutral halogen bonding acceptors, such as lutidines. Therefore, we investigate the photochemistry of a series of azobenzene photoswitches. Upon introduction of iodoethynyl groups, the halogen bonding donor properties are significantly strengthened in solution. However, the bathochromic shift of the π→π* band leads to a partial overlap with the n→π* band, making it slightly more difficult to address. The introduction of iodine substituents is furthermore accompanied with a diminishing thermal half-life. A series of three azobenzenes with different halogen bonding donor properties are discussed in relation to their changing photophysical properties, rationalized by DFT calculations.

Key Role of π–π Complex in Diary Cross-Coupling between Aryldiazonium Salts and Arylboronic Acids using Photosensitizer-Free Gold/Photoredox Catalysis

2021 ◽  
Author(s):  
Yanhong Liu ◽  
Rong-Xiu Zhu ◽  
Chengbu Liu ◽  
Dongju Zhang
Keyword(s):  
Dft Calculations ◽  
Visible Light ◽  
Cross Coupling ◽  
Photoredox Catalysis ◽  
Arylboronic Acids ◽  
Type Complex ◽  
Free Gold ◽  
Π Complex ◽  
Td Dft

DFT and TD-DFT calculations were performed to better understand the photosensitizer-free visible-light-mediated Au-catalyzed cross-couplings between aryldiazonium salts and arylboronic acids. The π–π type complex between the aryldiazonium salt and the...

Structure and electron density of oxysulfide Sm2Ti2S2O4.9, a visible-light-responsive photocatalyst

2008 ◽  
Vol 64 (3) ◽  
pp. 291-298 ◽  
Author(s):  
Masatomo Yashima ◽  
Kiyonori Ogisu ◽  
Kazunari Domen
Keyword(s):  
Dft Calculations ◽  
Visible Light ◽  
Valence Band ◽  
Electron Density ◽  
Diffraction Data ◽  
Density Functional ◽  
Oxygen Deficiency ◽  
Covalent Bonds ◽  
Synchrotron Powder Diffraction ◽  
Visible Wavelengths

We report the crystal structure and electron density of samarium titanium oxysulfide, Sm2Ti2S2O4.9, photocatalyst obtained through the Rietveld analysis, maximum-entropy method (MEM) and MEM-based pattern fitting of the high-resolution synchrotron powder diffraction data taken at 298.7 K. The Sm2Ti2S2O4.9 has a tetragonal structure with the space group I4/mmm. Refined occupancy factors at the `equatorial' O1 and `apical' O2 sites were 0.994 (3) and 0.944 (12), respectively, which strongly suggest oxygen deficiency at the O2 site. Electron-density analyses based on the synchrotron diffraction data of Sm2Ti2S2O4.9 in combination with density-functional theory (DFT) calculations of stoichiometric Sm2Ti2S2O5 reveal covalent bonds between Ti and O atoms, while the Sm and S atoms are more ionic. The presence of S 3p and O 2p orbitals results in increased dispersion of the valence band, raising the top of the valence band and making the material active at visible wavelengths. The present DFT calculations of stoichiometric Sm2Ti2S2O5 indicate the possibility of overall splitting of water, although Sm2Ti2S2O4.9 works as a visible-light-responsive photocatalyst in aqueous solutions only in the presence of sacrificial electron donors or acceptors. The oxygen deficiency and cocatalyst seem to be factors affecting the catalytic activity.

scholarly journals Ligand and solvent control of selectivity in the C–H activation of a pyridylimine-substituted 1-naphthalene; a combined synthetic and computational study

2018 ◽  
Vol 47 (33) ◽  
pp. 11680-11690
Author(s):  
Rena Simayi ◽  
Simone M. Gillbard ◽  
Warren B. Cross ◽  
Eric G. Hope ◽  
Kuldip Singh ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Computational Study ◽  
Site Selectivity ◽  
Solvent Control ◽  
Experimental Findings ◽  
Chloride Salts ◽  
Substituted 1

The site-selectivity of C–H activation in a 1-substituted naphthalene is explored using palladium(ii) chloride salts; the experimental findings are fully supported by DFT calculations.

scholarly journals Tyrosine and Drug-like Late-stage Benzylic Functionalization via Photoredox Catalysis

2020 ◽  
Author(s):  
Tobias Brandhofer ◽  
Volker Derdau ◽  
María Mendez ◽  
Christoph Pöverlein ◽  
Olga Garcia Mancheno
Keyword(s):  
Natural Products ◽  
Visible Light ◽  
Late Stage ◽  
Medicinal Chemistry ◽  
Functional Group ◽  
Reaction Conditions ◽  
Site Selectivity ◽  
Wide Range ◽  
High Yields ◽  
Therapeutic Compounds

Abstract Visible light mediated late-stage functionalization is a rising field in synthetic and medicinal chemistry, allowing the fast and diversified modification of valuable, potentially therapeutic compounds such as peptides. However, there are relatively few mild methodologies for the C(sp3)-H functionalization of complex peptides. Herein, we report a visible light mediated photocatalytic protocol for the benzylic C-H modification of tyrosine and related C-H bonds. The embraced radical-cation/deprotonation strategy enables an incorporation of a wide range of valuable functional groups in high yields and chemoselectivity. The mild reaction conditions, site-selectivity and high functional group tolerance was highlighted by the functionalization of complex peptides, drugs and natural products, providing a promising synthetic platform in medicinal chemistry.

Visible-Light-Triggered Release of Sulfonamides in MOF/Ag-Based Nanoparticle Composites: Performance, Mechanism, and DFT Calculations

2018 ◽  
Vol 2 (1) ◽  
pp. 418-428 ◽  
Author(s):  
Xue-Yan Xu ◽  
Jing Zhang ◽  
Xudong Zhao ◽  
Huifen Fu ◽  
Chun Chu ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Visible Light ◽  
Triggered Release ◽  
Nanoparticle Composites

scholarly journals Origin of the enhanced photocatalytic activity of (Ni, Se, and B) mono- and co-doped anatase TiO2 materials under visible light: a hybrid DFT study

RSC Advances ◽  
2020 ◽  
Vol 10 (70) ◽  
pp. 43092-43102
Author(s):  
Hanan H. Ibrahim ◽  
Adel A. Mohamed ◽  
Ismail A. M. Ibrahim
Keyword(s):  
Photocatalytic Activity ◽  
Hydrogen Production ◽  
Dft Calculations ◽  
Visible Light ◽  
Water Splitting ◽  
Anatase Tio2 ◽  
Dft Study ◽  
Co Doped

Hybrid DFT calculations demonstrate that Ni, Se4+ and Se2− mono-doped and Ni/Se4+ co-doped TiO2 are potential photocatalysts for water splitting and hydrogen production.

scholarly journals Computational study on palladium-catalyzed alkenylation of remote δ-C(sp3)–H bonds with alkynes: a new understanding of mechanistic insight and origins of site-selectivity

RSC Advances ◽  
2018 ◽  
Vol 8 (53) ◽  
pp. 30186-30190 ◽  
Author(s):  
Hui-Min Yan ◽  
Ye Tian ◽  
Niu Li ◽  
Rong Chang ◽  
Zhu-Xia Zhang ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Computational Study ◽  
Mechanistic Insight ◽  
Site Selectivity ◽  
Palladium Catalyzed

Palladium-catalyzed alkenylation of δ-C(sp3)–H bonds with alkynes was conducted by DFT calculations, showing that the dimeric Pd2(OAc)4 mechanism reproduces experimental observations well.

scholarly journals A metal sulfide photocatalyst composed of ubiquitous elements for solar hydrogen production

2016 ◽  
Vol 52 (47) ◽  
pp. 7470-7473 ◽  
Author(s):  
Y. Shiga ◽  
N. Umezawa ◽  
N. Srinivasan ◽  
S. Koyasu ◽  
E. Sakai ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Production ◽  
Dft Calculations ◽  
Visible Light ◽  
Density Functional ◽  
Metal Sulfide ◽  
Tin Sulfide ◽  
Functional Theory ◽  
Solar Hydrogen ◽  
Solar Hydrogen Production

A visible-light-sensitive tin sulfide photocatalyst was designed based on a ubiquitous element strategy and density functional theory (DFT) calculations.

Sign in / Sign up

Export Citation Format

Share Document