Video Experimental Relacionado

Updated: Jun 16, 2025

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

Published on: November 21, 2017

Polimerización topoquímica de apertura de anillo de un oxatianetión

Alvaro Calderón-Díaz¹, Liam Ordner¹, Maximilian G Bernbeck¹

¹School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.

Journal of the American Chemical Society

|June 14, 2025

Resumen

Los cristales simples de oxatianetión (OTT) se someten a una polimerización espontánea de apertura de anillo para formar un polímero altamente cristalino (POTT) con estructuras helicoidales de mano derecha. Esta distinta polimerización topoquímica produce polímeros que contienen azufre bien definidos.

Área de la Ciencia:

Química de los polímeros
Ciencias de los materiales
La cristalografía

Sus antecedentes:

La polimerización topoquímica ofrece una ruta a los polímeros cristalinos.
El control de la polimerización en estado sólido es crucial para las propiedades del material.

Objetivo del estudio:

Investigar la polimerización topoquímica espontánea de apertura de anillos (topoROP) del enantiopuro oxatianetión (OTT).
Determinar la estructura y las propiedades del polímero resultante (POTT).

Principales métodos:

Difracción de rayos X de un solo cristal para estudiar las estructuras de monómeros y polímeros.
Polimerización de apertura de anillos topoquímicos de cristales OTT.
Experimentos de control con el monómero amorfo.

Principales resultados:

Polimerización espontánea, cuantitativa y estereospecífica de OTT a POTT cristalino.
POTT cristalino de alto peso molecular con cadenas helicoidales de mano derecha en una disposición antiparalela.
La polimerización procede a través de un mecanismo de sustitución nucleofílico concertado, suprimido en estados amorfos.

Conclusiones:

Se ha identificado una clase distinta de polimerización topoquímica.
Este método permite la preparación de polímeros altamente cristalinos que contienen azufre.
La estereospecificidad y la naturaleza cristalina del polímero están dictadas por la disposición en estado sólido del monómero.

Más Videos Relacionados

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers

Published on: December 16, 2022

Solid-phase Synthesis of [4.4] Spirocyclic Oximes

Solid-phase Synthesis of [4.4] Spirocyclic Oximes

Published on: February 6, 2019

Videos de Conceptos Relacionados

Base-Catalyzed Ring-Opening of Epoxides

Base-Catalyzed Ring-Opening of Epoxides

Due to their highly strained structures, epoxides can readily undergo ring-opening reactions through nucleophilic substitution, either in the presence of an acid or a base. The nucleophilic substitution reactions in the presence of acid are called acid-catalyzed ring-opening reactions, and nucleophilic substitution reactions in the presence of a base are called base-catalyzed ring-opening reactions. Epoxides undergo base-catalyzed ring-opening reactions in the presence of a strong nucleophile...

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

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

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...

Preparation of Epoxides

Preparation of Epoxides

Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of...

Acid-Catalyzed Ring-Opening of Epoxides

Acid-Catalyzed Ring-Opening of Epoxides

Epoxides that are three-membered ring systems are more reactive than other cyclic and acyclic ethers. The high reactivity of epoxides originates from the strain present in the ring. This ring strain acts as a driving force for epoxides to undergo ring-opening reactions either with halogen acids or weak nucleophiles in the presence of mild acid. The acid catalyst converts the epoxide oxygen, a poor leaving group, into an oxonium ion, a better leaving group, making the reaction feasible. The...

Olefin Metathesis Polymerization: Overview

Olefin Metathesis Polymerization: Overview

Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists...

Thermal and Photochemical Electrocyclic Reactions: Overview

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.