JoVE - Journal of Visualized Experiments
JoVE Visualize
Contact Us

Photo-responsive metal-organic gels of rigid phenylene-1,3-di-substituted angular dienes with metal halides: gel-to-gel transformations triggered by [2 + 2] polymerization

  • 0Department of Chemistry, Indian Institute of Technology, Kharagpur-721302, India. kbiradha@chem.iitkgp.ernet.in.
Transactions +

|

February 19, 2024

|

February 19, 2024

View abstract on PubMed

Summary

This summary is machine-generated.

This study introduces gel-to-gel transformations using [2+2] photopolymerization in metal-organic gels (MOGs). This novel method creates new MOGs with enhanced rigidity, overcoming limitations of traditional gel modification techniques.

Area Of Science

  • Materials Science
  • Polymer Chemistry
  • Supramolecular Chemistry

Background

  • Gel-to-gel transformations are rare post-modification processes.
  • Modifying existing gelators often destabilizes the gel structure, leading to sol formation.
  • Developing new methods to create robust and tunable gel materials is crucial.

Purpose Of The Study

  • To report the first instance of gel-to-gel transformations in metal-organic gels (MOGs).
  • To investigate the [2+2] photopolymerization of MOGs incorporating metal halides and rigid dienes.
  • To explore the potential for creating novel MOGs with improved properties.

Main Methods

  • Utilizing [2+2] photopolymerization triggered by UV irradiation.
  • Synthesizing metal-organic gels (MOGs) from metal halides and rigid dienes.
  • Characterizing the resulting gels and xerogels to assess structural and property changes.

Main Results

  • MOGs and their xerogels successfully underwent [2+2] polymerization upon UV exposure.
  • Demonstrated a rare gel-to-gel transformation, altering molecular assemblies.
  • Achieved gels with modified mechanical and chemical properties.

Conclusions

  • [2+2] photopolymerization offers a viable route for gel-to-gel transformations in MOGs.
  • This approach enables the synthesis of novel MOGs with enhanced rigidity.
  • The findings open new avenues for designing advanced supramolecular materials.

Related Concept Videos

Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET) 00:53

1.9K

Acyclic diene metathesis polymerization or ADMET polymerization involves cross-metathesis of terminal dienes, such as 1,8-nonadiene, to give linear unsaturated polymer and ethylene. As ADMET is a reversible process, the formed ethylene gas must be removed from the reaction mixture to complete the polymerization process.
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...

[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction 01:16

10.2K

The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.

From a molecular orbital perspective, the interacting lobes of the two π systems must be in phase...

Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP) 01:16

2.6K

Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring...

Photochemical Electrocyclic Reactions: Stereochemistry 01:26

1.8K

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

Ziegler–Natta Chain-Growth Polymerization: Overview 01:17

3.3K

Ziegler–Natta polymerization is another form of addition or chain‐growth polymerization used for synthesizing linear polymers over branched polymers. The catalyst used for polymerization is the Ziegler–Natta catalyst, named after Karl Ziegler and Giulio Natta, who developed it in 1953. This catalyst is an organometallic complex of titanium tetrachloride and triethyl aluminum, with the active form of the catalyst being an alkyl titanium compound. Using the Ziegler–Natta...

Electrophilic 1,2- and 1,4-Addition of X<sub>2</sub> to 1,3-Butadiene 01:14

2.5K

Electrophilic addition of halogens to alkenes proceeds via a cyclic halonium ion to form a 1,2-dihalide or a vicinal dihalide.

Conjugated dienes react with halogens in a similar manner. However, in addition to the 1,2-dihalide, they also form a 1,4-dihalide. The mechanism involves two steps.
First, a nucleophilic attack by one of the diene π bonds on the electrophilic center of the polarized halogen molecule forms a halonium ion intermediate. This is followed by a nucleophilic attack of...