Tae‐Lim Choi 교수

Highly active with ultrafast initiation, the catalyst 1 promotes the controlled, living, ring-opening polymerization of various norbornene and 7-oxonorbornene derivatives (see scheme). The high ki/kp ratio associated with the polymerization reactions results in better molecular-weight control and narrower polydispersity indexes (PDIs, ki=rate constant for initiation, kp=rate constant for polymerization).

Electronic and steric properties of the substituents on the amide nitrogen atom govern the yield and rate of the cross-metathesis between a variety of α,β-unsaturated amides and olefins with 1 as the catalyst. This influence is the result of deactivation of the catalyst by chelation of the carbonyl group to the metal. However, an increase in catalyst loading compensates for the chelation effect. Supporting information for this article is available on the WWW under http://www.angewandte.com or fr

A noble ferrocene-containing conjugated polymer PFT2-Fc was synthesized, and its electrochemical and physical properties were characterized. This polymer was fabricated into a device with metal−polymer-ITO structure and showed a I−V characteristics for typical nonvolatile memory.

Well-defined nanostructures composed of conjugated polymers have attracted significant attention due to their intriguing electronic and optical properties. However, precise control of the size and uniformity of these semiconducting nanostructures is still rare and challenging, despite recent advances in strategies to obtain self-assembled nanostructures with narrow dispersions. Herein, we demonstrate the preparation of fluorescent conjugated block copolymers by one-shot polymerization and rapid

Olefin metathesis has become a valuable reaction in organic synthesis, as has been demonstrated by its frequent use as the key bond constructions for total syntheses of many natural products. With the recent discovery of highly active catalyst 1, trisubstituted and functionalized alkenes have been synthesized efficiently by cross-metathesis (CM), further expanding the substrate scope for this reaction. With these successes in hand, unprecedented metathesis reactions were explored. There have bee

A variety of highly A,B-alternating copolymers are formed from diacrylates and cycloalkenes in the presence of [Cl2(PCy3)(H2IMes)RuCHPh] (1). The high conversion and the high selectivity come from the thermodynamically favored formation of a CC double bond between these monomers.

Herein, we report a highly efficient Suzuki-Miyaura catalyst-transfer polycondensation (SCTP) of 3-alkylthiophenes using bench-stable but highly active Buchwald dialkylbiarylphospine Pd G3 precatalysts and N-methylimidodiacetic (MIDA)-boronate monomers. Initially, the feasibility of the catalyst-transfer process was examined by screening various dialkylbiarylphospine-Pd(0) species. After optimizing a small molecule model reaction, we identified both RuPhos and SPhos Pd G3 precatalysts as excelle

Hoch aktiver Katalysator, ultraschnelle Initiation: Der Katalysator 1 vermittelt die lebende Ringöffnungspolymerisation von Norbornen- und 7-Oxonorbornen-Derivaten (siehe Schema). Das hohe Verhältnis ki/kp, das dabei mit 1 erreicht wird, führt zu besonders guter Steuerung des Molekulargewichts und zu einem niedrigen Polydispersitätsindex (PDI).

Monomers derived from glucose and galactose, which contain an endocyclic alkene (in the sugar ring) and a terminal alkyne, underwent a cascade polymerization to prepare new polymers with the ring-opened sugar incorporated into the polymer backbone. Polymerizations were well-controlled, as demonstrated by a linear increase in molecular weight with monomer-to-initiator ratio and generally narrow molecular weight dispersity values. The living nature of the polymerization was supported by the prepar

Catalyst-transfer polymerization has revolutionized the field of polymer synthesis due to its living character, but for a given catalyst system, the polymer scope is rather narrow. Herein we report a highly efficient Suzuki-Miyaura catalyst-transfer polymerization (SCTP) that covers a wide range of monomers from electron-rich (donor, D) to electron-deficient (acceptor, A) (hetero)arenes by rationally designing boronate monomers and using commercially available Buchwald RuPhos and SPhos Pd G3 pre

Two-dimensional (2D) polymer nanosheets have been attracting immense attention owing to their potential applications in optical devices, membranes, and catalysis. However, creating uniform monolayered 2D nanosheets through polymer self-assembly is very challenging, especially when using homopolymers. In this work, we designed a new crystalline polyacetylene that contains fluorenes and triisopropylsilyl side chains, which could self-assemble into sharp-edged 5-nm-thick square nanosheets with a na

The highly active catalyst 2 was used in tandem RCM to make molecules with various ring systems containing α,β-unsaturated carbonyl compounds.

Preparing well-defined semiconducting nanostructures from conjugated polymers is of paramount interest for organic optoelectronic devices. Several studies have demonstrated excellent structural and size control from block copolymers (<b>BCPs</b>) containing non-conjugated blocks <i>via</i> crystallization-driven self-assembly (CDSA); however, the precise control of their size and shape remains a challenge due to their poor solubility, causing rapid and uncontrolled aggregation. This study presen

For the demonstration of remote‐controllable actuators, a dendronized polymer (denpol) is newly designed and successfully synthesized by ring‐opening metathesis polymerization of azobenzene‐based macromonomers. The incorporation of azobenzene mesogens into the denpols helps to construct finely tuned hierarchical superstructures with anisotropic physical properties and reversible photoisomerization. The polynorbornene backbones and azobenzene side chains in the uniaxially oriented films are align

Cyclopolymerisation of 1,6-heptadiyne derivatives by Grubbs catalysts gives the conjugated polymers containing a five-membered ring repeat unit. The first example of cyclopolymerisation of 1,7-octadiyne derivatives is demonstrated here to give a new class of conjugated polymer that contains six-memebered rings. This polymerisation was very challenging and efficient cyclopolymerisation was achieved only with monomers that showed a significant Thorpe–Ingold effect. By using a third-generation Grub