Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Photochemical Electrocyclic Reactions: Stereochemistry01:26

Photochemical Electrocyclic Reactions: Stereochemistry

The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Cycloaddition Reactions: MO Requirements for Photochemical Activation01:12

Cycloaddition Reactions: MO Requirements for Photochemical Activation

Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
Thermal and Photochemical Electrocyclic Reactions: Overview01:26

Thermal and Photochemical Electrocyclic Reactions: Overview

Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
Electrophilic 1,2- and 1,4-Addition of HX to 1,3-Butadiene01:17

Electrophilic 1,2- and 1,4-Addition of HX to 1,3-Butadiene

The electrophilic addition of hydrogen halides such as HBr to alkenes and nonconjugated dienes gives a single product as per Markovnikov’s rule.
Thermal Electrocyclic Reactions: Stereochemistry01:17

Thermal Electrocyclic Reactions: Stereochemistry

The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Radical Chain-Growth Polymerization: Chain Branching01:17

Radical Chain-Growth Polymerization: Chain Branching

The skeletal structure of polymers synthesized via radical polymerization is always branched. For example, the polymerization of ethylene by radical polymerization results in a low-density grade of polyethylene with a heavily branched skeletal structure. Here, the radical site abstracts hydrogen from the growing chain, and the radical site shifts from the end (a primary carbon center) to anywhere within the growing chain (a secondary carbon center). Consequently, the part of the chain from the...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Lipids and lipid nanoparticles functionalized with randomized poly(ethylene glycol) (rPEG) for mRNA delivery.

Chemical science·2026
Same author

D‑Penicillamine‑Stabilized Gold Nanoclusters as a Selective Fluorescent Sensor for Tetracyclines.

Journal of fluorescence·2026
Same author

How to Handle Hard-to-Purify Polymers: Ammonium Sulfate Precipitation of rPEG as a Prototype for Amorphous and Flexible Polymers.

ACS macro letters·2026
Same author

Shaping the Gradient: Ether-Type Polar Modifiers for the Statistical Anionic Copolymerization of Styrene and Isoprene.

ACS macro letters·2026
Same author

Metal Halide Perovskite/Chalcohalide Heterojunctions for the Photoinduced Oxidative Coupling of <i>p</i>‑Substituted Thiophenols.

ACS applied nano materials·2026
Same author

Novel polymer series for pharmaceutical applications: alpha-hydroxycarboxylic acid modified polymethacrylates.

International journal of pharmaceutics·2026

Related Experiment Video

Updated: Jul 5, 2026

[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst
09:12

[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst

Published on: May 21, 2019

Photocatalysis within hyperbranched polyethers with a benzophenone core.

Lourdes Pastor-Pérez1, Emilie Barriau, Holger Frey

  • 1Instituto de Ciencia Molecular (ICmol), Universidad de Valencia, Paterna Valencia, Spain.

The Journal of Organic Chemistry
|May 21, 2008
PubMed
Summary
This summary is machine-generated.

Hyperbranched polyethers with a benzophenone core show promise as durable photocatalysts. Even after multiple uses, the highest molecular weight polymer maintained its performance and structure, highlighting its photostability.

More Related Videos

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst
07:39

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst

Published on: June 8, 2016

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization
12:19

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization

Published on: November 29, 2018

Related Experiment Videos

Last Updated: Jul 5, 2026

[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst
09:12

[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst

Published on: May 21, 2019

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst
07:39

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst

Published on: June 8, 2016

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization
12:19

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization

Published on: November 29, 2018

Area of Science:

  • Polymer Chemistry
  • Photocatalysis
  • Organic Synthesis

Background:

  • Photocatalysis is crucial for sustainable chemical transformations.
  • Developing stable and reusable photocatalysts is an ongoing challenge.
  • Hyperbranched polymers offer unique structural properties for catalyst design.

Purpose of the Study:

  • To evaluate hyperbranched polyethers with a tetrafunctionalized benzophenone core as photocatalysts.
  • To assess the stability and reusability of these polymer photocatalysts.
  • To investigate the influence of polymer structure on photocatalytic performance.

Main Methods:

  • Utilized quenching and product studies to assess photocatalyst suitability.
  • Employed a triplet photosensitized transformation of an unsaturated diazo compound as a model reaction.
  • Analyzed product distribution and catalyst integrity over multiple catalytic cycles.

Main Results:

  • Hyperbranched polyethers with a benzophenone core demonstrated photocatalytic activity.
  • The highest molecular weight polymer exhibited consistent product distribution across several cycles.
  • This indicates excellent photostability and resistance to degradation under prolonged irradiation.

Conclusions:

  • Hyperbranched polyethers with benzophenone cores are suitable photocatalysts.
  • The polymer's stabilizing shell contributes to its remarkable photostability and reusability.
  • These findings support the potential of tailored polymer architectures in advanced photocatalysis.