Diarylethenes with a Narrow Singlet-Triplet Energy Gap Sensitizer: a Simple Strategy for Efficient Visible-Light Photochromism

2018 ◽  
Vol 6 (6) ◽  
pp. 1700847 ◽  
Author(s):  
Zhiwei Zhang ◽  
Junji Zhang ◽  
Bin Wu ◽  
Xin Li ◽  
Yi Chen ◽  
...  
Keyword(s):  
Visible Light ◽  
Energy Gap ◽  
Triplet Energy ◽  
Simple Strategy

scholarly journals A building-block design for enhanced visible-light switching of diarylethenes

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhiwei Zhang ◽  
Wenhui Wang ◽  
Peipei Jin ◽  
Jiadan Xue ◽  
Lu Sun ◽  
...  
Keyword(s):  
Visible Light ◽  
Building Block ◽  
Energy Gap ◽  
Molecular Design ◽  
Block Design ◽  
Triplet Energy ◽  
Responsive Materials ◽  
High Penetration ◽  
Penetration Ability ◽  
Light Excitation

Abstract Current development of light-responsive materials and technologies imposes an urgent demand on visible-light photoswitching on account of its mild excitation with high penetration ability and low photo-toxicity. However, complicated molecular design and laborious synthesis are often required for visible-light photoswitch, especially for diarylethenes. Worse still, a dilemma is encountered as the visible-light excitation of the diarylethene is often achieved at the expense of photochromic performances. To tackle these setbacks, we introduce a building-block design strategy to achieve all-visible-light photochromism with the triplet-sensitization mechanism. The simply designed diarylethene system is constructed by employing a sensitizer building-block with narrow singlet-triplet energy gap (ΔEST) to a diarylethene building-block. A significant improvement on the photochromic efficiency is obtained as well as an enhanced photo-fatigue resistance over those under UV irradiation. The balance between the visible-light excitation and decent photochromism is thus realized, promoting a guiding principle for the visible-light photochromism.

Visible-Light-Mediated Tandem Sulfonylation/Cyclization of Vinyl Azides with Sulfonyl Hydrazines for the Synthesis of 6-(Sulfonylmethyl)phenanthridines under Mild Conditions

Synlett ◽  
2019 ◽  
Vol 30 (08) ◽  
pp. 955-960 ◽  
Author(s):  
Liu-Liang Mao ◽  
Li-Xia Quan ◽  
Xian-Hong Zhu ◽  
Cong-Bin Ji ◽  
An-Xi Zhou ◽  
...  
Keyword(s):  
Visible Light ◽  
Mild Conditions ◽  
Simple Strategy ◽  
Vinyl Azides

A visible-light-mediated tandem sulfonylation/cyclization of vinyl azides with sulfonyl hydrazines was developed that provides an efficient and simple strategy for the synthesis of valuable 6-(sulfonylmethyl)phenanthridines with a broad substrate scope and satisfactory yields under mild conditions.

scholarly journals Facile Preparation of Efficient WO3Photocatalysts Based on Surface Modification

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Min Liu ◽  
Hongmei Li ◽  
Yangsu Zeng
Keyword(s):  
Photocatalytic Activity ◽  
Surface Modification ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Impregnation Method ◽  
Light Spectra ◽  
Simple Strategy ◽  
Visible Light Active ◽  
Efficient Charge ◽  
Surface Modified

Tungsten trioxide (WO3) was surface modified with Cu(II) nanoclusters and titanium dioxide (TiO2) nanopowders by using a simple impregnation method followed by a physical combining method. The obtained nanocomposites were studied by scanning electron microscope, X-ray photoelectron spectroscopy spectra, UV-visible light spectra, and photoluminescence, respectively. Although the photocatalytic activity of WO3was negligible under visible light irradiation, the visible light photocatalytic activity of WO3was drastically enhanced by surface modification of Cu(II) nanoclusters and TiO2nanopowders. The enhanced photocatalytic activity is due to the efficient charge separation by TiO2and Cu(II) nanoclusters functioning as cocatalysts on the surface. Thus, this simple strategy provides a facile route to prepare efficient visible-light-active photocatalysts for practical application.

scholarly journals Visible Light-Enabled Paternò-Büchi Reaction via Triplet Energy Transfer for the Synthesis of Oxetanes

2020 ◽  
Author(s):  
Katie Rykaczewski ◽  
Corinna Schindler
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Uv Light ◽  
Cycloaddition Reaction ◽  
High Energy ◽  
Triplet Energy ◽  
Reaction Conditions ◽  
Triplet Energy Transfer

<div> <p>One of the most efficient ways to synthesize oxetanes is the light-enabled [2+2] cycloaddition reaction of carbonyls and alkenes, referred to as the Paternò-Büchi reaction. The reaction conditions for this transformation typically require the use of high energy UV light to excite the carbonyl, limiting the applications, safety, and scalability. We herein report the development of a visible light-mediated Paternò-Büchi reaction protocol that relies on triplet energy transfer from an iridium-based photocatalyst to the carbonyl substrates. This mode of activation is demonstrated for a variety of aryl glyoxylates and negates the need for both, visible light-absorbing carbonyl starting materials or UV light to enable access to a variety of functionalized oxetanes in up to 99% yield.</p> </div> <br>

Enhanced H2 evolution over an Ir-doped SrTiO3 photocatalyst by loading of an Ir cocatalyst using visible light up to 800 nm

2018 ◽  
Vol 54 (75) ◽  
pp. 10606-10609 ◽  
Author(s):  
Sho Suzuki ◽  
Hiroe Matsumoto ◽  
Akihide Iwase ◽  
Akihiko Kudo
Keyword(s):  
Visible Light ◽  
Energy Gap ◽  
H2 Evolution

H2-reduction after loading of an Ir cocatalyst drastically enhanced the H2 evolution over an SrTiO3:Ir photocatalyst with a narrow energy gap.

Aggregation-induced emission (AIE)-active molecules bearing singlet oxygen generation activities: the tunable singlet–triplet energy gap matters

2019 ◽  
Vol 55 (10) ◽  
pp. 1450-1453 ◽  
Author(s):  
Chengkai Zhang ◽  
Yanqian Zhao ◽  
Dandan Li ◽  
Jiejie Liu ◽  
Heguo Han ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Cell Apoptosis ◽  
Near Infrared ◽  
Energy Gap ◽  
Intersystem Crossing ◽  
Triplet Energy ◽  
Oxygen Generation ◽  
Two Photon ◽  
Singlet Oxygen Generation ◽  
Infrared Excitation

Two-photon active photosensitizers showed relatively strong intersystem crossing facilitating 1O2 generation and cell apoptosis with near-infrared excitation.

scholarly journals Front Cover: Highly Fluorescent Emitters Based on Triphenylamine‐π‐Triazine (D‐π‐A) System: Effect of Extended Conjugation on Singlet‐Triplet Energy Gap (Asian J. Org. Chem. 9/2020)

2020 ◽  
Vol 9 (9) ◽  
pp. 1249-1249
Author(s):  
Shiv Kumar ◽  
Pachaiyappan Rajamalli ◽  
David B. Cordes ◽  
Alexandra M. Z. Slawin ◽  
Eli Zysman‐Colman
Keyword(s):  
Energy Gap ◽  
Triplet Energy ◽  
System Effect ◽  
Front Cover

scholarly journals TAO-DFT Study on the Electronic Properties of Diamond-Shaped Graphene Nanoflakes

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1236 ◽  
Author(s):  
Hong-Jui Huang ◽  
Sonai Seenithurai ◽  
Jeng-Da Chai
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Quantitative Measure ◽  
Smooth Transition ◽  
Von Neumann Entropy ◽  
Triplet Energy ◽  
Von Neumann ◽  
Graphene Nanoflakes ◽  
Radical Nature

At the nanoscale, it has been rather troublesome to properly explore the properties associated with electronic systems exhibiting a radical nature using traditional electronic structure methods. Graphene nanoflakes, which are graphene nanostructures of different shapes and sizes, are typical examples. Recently, TAO-DFT (i.e., thermally-assisted-occupation density functional theory) has been formulated to tackle such challenging problems. As a result, we adopt TAO-DFT to explore the electronic properties associated with diamond-shaped graphene nanoflakes with n = 2–15 benzenoid rings fused together at each side, designated as n-pyrenes (as they could be expanded from pyrene). For all the n values considered, n-pyrenes are ground-state singlets. With increasing the size of n-pyrene, the singlet-triplet energy gap, vertical ionization potential, and fundamental gap monotonically decrease, while the vertical electron affinity and symmetrized von Neumann entropy (which is a quantitative measure of radical nature) monotonically increase. When n increases, there is a smooth transition from the nonradical character of the smaller n-pyrenes to the increasing polyradical nature of the larger n-pyrenes. Furthermore, the latter is shown to be related to the increasing concentration of active orbitals on the zigzag edges of the larger n-pyrenes.

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