Synthesis of α,ω-End Functionalized Polydienes: Allylic-Bearing Heteroleptic Aluminums for Selective Alkylation and Transalkylation in Coordinative Chain Transfer Polymerization.

There are still challenges in the preparation of difunctional stereoregular polydienes, especially for the construction of initiating chain-end functionalization. Coordinative chain transfer polymerization (CCTP) provides a way to achieve the goal but usually requires sophisticated functionalized catalysts as well as expensive chain transfer agents (CTAs). In this work, heteroleptic aluminum with oligo(dienyl) substituents (oligo-Al agents) were readily prepared by living anionic polymerization (LAP) technique.

Boron-Catalyzed Polymerization of Phenyl-Substituted Allylic Arsonium Ylides toward Nonconjugated Emissive Materials from C3/C1 Monomeric Units.

Two novel allylic arsonium ylide monomers with a phenyl (steric and electronic effect) group at different positions were synthesized and used in boron-catalyzed polymerization to produce a series of well-defined polymers, poly(2-phenyl-propenylene--2-phenyl-propenylidene) (P2-PhAY) and poly(3-phenyl-propenylene--3-phenyl-propenylidene) (P3-PhAY), with unusual structures but a controllable molecular weight and relatively low polydispersity. The backbone of these polymers consists of a mixture of C1 (chain grows by one carbon atom at a time) and C3 (chain grows by three carbon atoms at a time) monomeric units, as determined by H, C, and H-C HSQC 2D NMR. Based on the experimental results and density functional theoretical (DFT) calculations, we were able to propose a mechanism that takes into account not only the steric hindrance, but also the electron effect of the phenyl group.

Investigation of the Locked-Unlocked Mechanism in Living Anionic Polymerization Realized with 1-(Tri-isopropoxymethylsilylphenyl)-1-phenylethylene.

Reported is an intriguing advance in living anionic polymerization (LAP) by a "locked-unlocked" mechanism in which the living anionic species can be quantitatively locked by end-capping with 1-(tri-isopropoxymethylsilylphenyl)-1-phenylethylene (DPE-Si(O-iPr) ) and can be unlocked by adding the key, sodium 2,3-dimethylpentan-3-olate (NaODP). These new insights into this mechanism were carefully confirmed by designing reactions involving sequential feeding of quantitative DPE-Si(O-iPr) and traditional monomers mixed with NaODP, and subsequently characterizing the corresponding samples, taken during the feeding process, by GPC, NMR, and MALDI-TOF-MS techniques. The switch from the locked to unlocked state was clearly confirmed by these characterization techniques.

Facile Synthesis of In-Chain, Multicomponent, Functionalized Polymers via Living Anionic Copolymerization through the Ugi Four-Component Reaction (Ugi-4CR).

By combining living anionic polymerization and the highly efficient Ugi four-component reaction (Ugi-4CR), in-chain, multicomponent, functionalized polymers are facilely synthesized with efficient conversation and abundant functionality. l-[4-[N,N-Bis(trimethylsilyl)-amino]phenyl]-l-phenylethylene, which is redefined as Ugi-DPE, is anionically copolymerized to synthesize the well-defined in-chain, multi-amino functionalized polystyrene (P(St/DPE-NH )), the backbone for the Ugi-4CR, via hydrolysis of the copolymerization (P(St/Ugi-DPE)). Subsequently, several functionalized components are facilely clicked onto P(St/DPE-NH ) to investigate the model reactions of the in-chain, multicomponent functionalization via the Ugi-4CR.

Study on the Mechanism of a Side Coupling Reaction during the Living Anionic Copolymerization of Styrene and 1-(Ethoxydimethylsilyphenyl)-1-phenylethylene (DPE-SiOEt).

A 1,1-diphenylethylene (DPE) derivative with an alkoxysilyl group (DPE-SiOEt) was synthesized. It was end-capped with poly(styryl)lithium (PSLi) and then copolymerized with styrene via living anionic polymerization (LAP) in a non-polar solvent at room temperature. The observed side coupling reaction was carefully investigated by end-capping the polymer.

Facile Synthesis of DendriMac Polymers via the Combination of Living Anionic Polymerization and Highly Efficient Coupling Reactions.

Two DendriMac polymers (Dendri-hydr and Dendri-click) are efficiently and conveniently synthesized via the combination of living anionic polymerization (LAP) and hydrosilylation/click chemistry. Based on the end-capping of DPE derivatives (DPE-SiH and DPE-DA) toward polymeric anions, the polymeric core and arms are effectively synthesized, and the base polymers can be regarded as polymeric bricks. Hydrosilylation and click chemistry are used as coupling reactions to construct the DendriMac polymers with high efficiency and convenience.

Synthesis of bottlebrush polystyrenes with uniform, alternating, and gradient distributions of brushes via living anionic polymerization and hydrosilylation.

By combining living anionic polymerization and hydrosilylation, densely grafted bottlebrush polymers with controlled spacing of branch points are prepared. Dimethyl(4-vinylphenyl)silane and dimethyl(4-(1-phenylvinyl)phenyl)silane are anionically (co)polymerized to synthesize uniform, alternating, and gradient in-chain silyl-hydride (Si-H) functionalized backbones. The spacing of branch points is controlled effectively by regulating the distribution of Si-H groups along the backbones.