Synthesis of polymers having zwitterionic structure via the radical polymerization of 4-vinylphenyl isothiocyanate/cyclic amidine adduct

Polymers having a zwitterionic pendant group have found a wide range of applications such as fungicides, fire-retardants, lubricating oil additives, emulsifiers, cryoprotectants, and electronic materials. Their properties depend not only on the polymer main chains but also on the zwitterionic structures. In this article, the synthesis of novel polymers having zwitterionic structures is described. A zwitterionic monomer (4-vinylphenyl isothiocyanate [VPI]-1,2-dimetyl-1,4,5,6,-tetrahydropirimidine [DMTHP]) was synthesized by the reaction of VPI and a cyclic amidine DMTHP. A radical polymerization of VPI-DMTHP was carried out using 2,2′-azobis(2,4-dimethyl-4-methoxy)valeronitrile (V-70) as an initiator to give poly(VPI-DMTHP). The obtained poly(VPI-DMTHP) was not soluble in any of the investigated organic solvents, probably because it had a networked structure resulting from the ionic interactions. Copolymers of VPI-DMTHP and other vinyl monomers such as styrene, methyl methacrylate, t-butyl methacrylate, and N-vinylpyrrolidone were synthesized. The obtained copolymers were also insoluble in all of the examined common organic solvents even when the VPI-DMTHP content was low (5 mol %), indicating the existence of strong ionic interactions in the zwitterionic moieties. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2303–2309     

Chemical reaction kinetics measurements for single and blended amines for CO2 postcombustion capture applications

The present study has established the direct pseudo–first‐order reaction kinetics of different aqueous‐based single and blended amines over the temperature range of 298.15‐313.15 K using stopped‐flow techniques. The single amines include one primary amine (monoethanolamine, MEA), two secondary amines (diethanolamine, DEA and 2‐ethyl(amino)ethanol, 2EAE), four tertiary amines (N‐methyldiethanolamine, MDEA, 1‐dimethylamino‐2‐propanol, 1DMA2P, 3‐dimethylamino‐1‐propanol, 3DMA1P, and 2‐dimethylaminoethanol, 2DMAE), one sterically hindered amine (2‐amino‐2‐methyl‐1‐propanol, AMP), and one cyclic diamine (piperazine, PZ). The blend systems used are MEA/PZ, DEA/PZ, MDEA/PZ, AMP/PZ, MEA/AMP, MDEA/2EAE, 1DMA2P/2EAE, 3DMA1P/2EAE, and 2DMAE/2EAE. Different reaction mechanisms for the reaction of CO₂ with aqueous solutions of amines, such as base‐catalysis, zwitterion, termolecular, hybrid of zwitterion, hybrid of base‐catalysis‐zwitterion, and hybrid of base‐catalysis‐termolecular reaction mechanisms, are used to correlate the experimental data. For the single amines, the zwitterion mechanism is well suited to fit the experimental data of primary, secondary, sterically hindered and cyclic amines with an absolute average deviation (AAD%) less than 5%. The base‐catalysis mechanism fits the experimental data of all the tertiary amines well with an AAD less than 5%. For the blends, the hybrid of zwitterion mechanism fits the experimental data of MEA/PZ, DEA/PZ, AMP/PZ, and MEA/AMP well with an AAD less than 5%, whereas the hybrid of base‐catalysis‐zwitterion mechanism fits the experimental data of MDEA/PZ, MDEA/2EAE, 1DMA2P/2EAE, 3DMA1P/2EAE, and 2DMAE/2EAE well with an AAD less than 5%.     

Reversible crosslinking and decrosslinking of polymers containing alcohol moiety using an acyclic bifunctional vicinal triketone

In this article, we report reversible crosslinking and decrosslinking systems of commercially available alcoholic polymers, using a bifunctional vicinal triketone (bistriketone) as a crosslinking reagent. A small amount of the bistriketone (0.2 equiv of the tricarbonyl moiety relative to the OH group of the polymer) was added to a solution of poly(2‐hydroxyethyl methacrylate) (PHEMA) in dimethyl sulfoxide (DMSO). After 4 days, the networked polymer was obtained as a yellow‐colored gel in 97% yield. Conversely, the resulting gel could be decrosslinked by treatment with MeOH for 4 days to recover the original PHEMA in 94% yield as well as the bistriketone in 54% yield. The network formation and dissociation behaviors were investigated in detail by ¹H NMR and size exclusion chromatography experiments. Similarly to PHEMA, reversible crosslinking and decrosslinking of poly(vinyl alcohol) were achieved by addition of the bistriketone and by treatment of the resulting gel with H₂O/DMSO (1/9, v/v), respectively. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 921–928     

Ugi three-component reaction of alcohols,amines and isocyanides: A new approach to the synthesis of cyclic amidines

We have developed a novel, simple, efficient and one pot synthetic protocol for the synthesis of cyclic amidines via Ugi three-component reaction of alcohols, amines, and isocyanides.     

Development and application of novel ring‐opening polymerizations to functional networked polymers

This Highlight gives an overview of the recent progress in development of new ring‐opening polymerizations (ROPs) and their applications to functional networked polymers in our group. The described ROPs involve thermally induced polymerization of 1,3‐benzoxazine, anionic alternating copolymerizations of epoxides and lactones, and those exhibiting equilibrium nature. These ROPs were successfully applied to the syntheses of the relevant networked polymers, leading to their distinctive features such as high thermal stability, small volume shrinkage, and selective decrosslinking ability, which enabled design and development of next generation materials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4847–4858, 2009     

Selective nucleophilic additions to poly(methacrylate)s containing isothiocyanate moieties in the side chains and their application in cross‐linking

Reactivity of isothiocynate moieties in the side chain of polymethacrylate with amine, alcohol, or thiol was investigated, and the reactions were applied to preparation of networked polymers. Isothiocyanate of polymer side chain rapidly reacted with amines without a catalyst, to give the corresponding thioureas. However, it did not react with alcohols or thiols under the same conditions. Using 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) as a catalyst, addition of alcohols or thiols to the isothiocyanate proceeded smoothly. Addition of amines, alcohols, and thiols to isothiocyanates moiety contained in the side chain of polymethacrylate also proceeded readily with or without the catalyst, respectively, to effectively give the corresponding side chain modified polymers. Occurrence of these additions was confirmed by ¹H NMR and IR measurements. Glass transition temperatures and thermal decomposition temperatures of the obtained polymers were investigated by differential scanning calorimetry and thermogravimetric analysis. Networked polymers were easily prepared by addition of 1,6‐hexamethylenediamine or hexamethylene glycol to the polymethacrylate having isothiocyanato groups. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1832–1842     

A Novel Construction of Ring-Opening Polymerization and Chemical Recycling System

This article summarizes our recent efforts to chemical recycling of polymeric materials based on the equilibrium polymerization character of cyclic monomers. Spiro orthoesters ( SOE s), bicyclo orthoester, cyclic carbonates, and dithiocarbonates undergo ring-opening polymerization to afford the corresponding polymers, and the resulting polymers depolymerize to give the starting monomers under cationic or anionic conditions. Further, crosslinking and decrosslinking systems of bifunctional SOE s and a polymer having SOE moiety in the side chain are described.     

Triallyl monomer bearing adamantane‐like core derived from naturally occurring myo‐inositol: Synthesis and polyaddition with dithiols

This paper deals with a triallyl monomer bearing a rigid adamantane‐like core derived from myo‐inositol, a naturally occurring cyclic hexaol. The core structure of the monomer can be readily constructed by orthoesterification of myo‐inositol. The polyaddition of the triallyl monomer with dithiols based on the thermally induced radical thiol‐ene reaction gives the corresponding networked polymers. These networked polymers exhibit much higher thermal stability than the comparative networked polymers obtained from a triallyl monomer bearing less rigid cyclohexyl core. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1193–1199     

Copper‐Catalyzed Cyclization/aza‐Claisen Rearrangement Cascade Initiated by Ketenimine Formation: An Efficient Stereocontrolled Synthesis of α‐Allyl Cyclic Amidines

An efficient and convenient synthesis of α‐allyl cyclic amidines has been achieved by applying a novel cascade reaction. Copper(I)‐mediated in situ N‐sulfonyl ketenimine formation from the reaction of a terminal alkyne with sulfonyl azide is followed by an intramolecular nucleophilic attack on the central carbon atom by an allylic tertiary amine, and then an aza‐Claisen rearrangement takes place through a chair transition state to furnish the titled amidines with complete stereocontrol.     

A versatile method for cyclic polymers from conjugated and unconjugated vinyl monomers

A versatile method was introduced to prepare cyclic polymers from both conjugated and unconjugated vinyl monomers. It was developed on the combination of the RAFT polymerization and the self‐accelerating double strain‐promoted azide‐alkyne click (DSPAAC) reaction. In this approach, a switchable chain transfer agent 1 was designed to have hydroxyl terminals and a functional pyridinyl group. The protonation and deprotonation of pyridinyl group endowed the chain transfer agent 1 with a switchable control capability to RAFT polymerization of both conjugated and unconjugated vinyl monomers. Based on this, RAFT polymerization and the following hydroxyl end group modification were used to prepare various azide‐terminated linear polymers including polystyrene, poly(N‐vinylcarbazole), and polystyrene‐block‐poly(N‐vinylcarbazole). Using sym‐dibenzo‐1,5‐cyclooctadiene‐3,7‐diyne (DBA) as small linkers, the corresponding cyclic polymers were then prepared via the DSPAAC reaction between DBA and azide terminals of the linear precursors. Due to the self‐accelerating property of DSPAAC reaction, this bimolecular ring‐closing reaction could efficiently produce the pure cyclic polymers using excess molar amounts of DBA to linear polymer precursors. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 1811–1820     

Coordination chemistry of 1,3,5-triazapentadienes

The methods of synthesis of 1,3,5-triazapentadienes (also known as imidoylamidines), as well as the preparation of their complexes, are reviewed. The former methods include mainly the Pinner, Ley and Muller syntheses, the amination of N-imidoylimidoates or of nitriles bearing strong electron-withdrawing groups, the desulfurizing amination of N-tiobenzoylbenzamidines and the reaction of perfluoro-5-aza-4-nonene with primary amines. The synthetic procedures for the complexes involve not only the coordination of a pre-formed 1,3,5-triazapentadiene but also the generation in situ of such a species, namely by condensation of amidines, by direct one-pot template synthesis from nitriles, by nucleophilic addition of amidines or related reagents to coordinated nitriles, by nucleophilic additions to dicyanamidate or hydrolytic conversion of triazines.     

An efficient one-pot synthesis of functionally diverse 2-aminothiazoles from isothiocyanates,amidines/guanidines and halomethylenes

An efficient one-pot method for the synthesis of 2-aminothiazoles using simple starting materials like isothiocyanates, amidines/guanidines and various halomethylenes is reported. The synthesis of 2-aminothiazoles involves reactions such as nucleophilic addition, S-alkylation and intramolecular nucleophilic substitution in which amines departs as the leaving group.     

Influence of residual impurities on ring‐opening metathesis polymerization after copper(I)‐catalyzed alkyne‐azide cycloaddition click reaction

Bottlebrush polymers (BBPs) are three‐dimensional polymers with great academic and industrial potential owing to their highly tunable and intricate architecture. The most popular method to synthesize BBPs is ring‐opening metathesis polymerization (ROMP) with Grubbs' catalyst, allowing living grafting‐through polymerization of macromonomers of up to ultrahigh molecular weights with narrow molecular weight distribution. In this case, it has been well recognized that the purity of macromonomers (MMs) is critical for a successful ROMP reaction. For MMs synthesized from reversible‐deactivation radical polymerization, Grubbs and Xia demonstrated that the better control of ROMP reaction can be achieved when they are prepared via “growth‐then‐coupling” method that is coupling a norbornenyl group to end‐functionalized prepolymers. However, these MMs can also contain various residual impurities from previous synthetic steps, which can potentially poison the catalyst and hamper the ROMP reaction. Herein, we intentionally doped possible impurities into purified MMs to identify the most poisoning species. As a result, it was found that alkyne‐functionalized norbornene most significantly retarded the ROMP reaction due to a formation of Ru‐vinyl‐carbene intermediates having low catalytic reactivity, whereas the other reagents such as solvent, Cu‐catalyst, ligands, and azido‐terminated prepolymers were relatively inert. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 726–737     

Polymers from aryl cyclic sulfonium zwitterions—photosensitive materials cast from and developed in water

Upon photolysis or heating, aryl cyclic sulfonium (ACS) zwitterions polymerize by ring‐opening and loss of charge to yield nonionic polymers. These water‐soluble monomers potentially are useful for photolithography because they can be cast from and developed in water. The ACS zwitterion from bisphenol A, 1,1′‐[isopropylidenebis(6‐hydroxy‐3,1‐phenylene)] bis (tetrahydrothiophenium hydroxide) bis(inner salt) (1) is a negative‐tone, photosensitive material that after photolysis yields a crosslinked film. Unexposed regions are removed by water. The cured film has a low dielectric constant, high volume resistivity, a high degree of planarization, low residual stress, thermogravimetric stability, acceptable fracture toughness, and high hardness. These are desirable properties for a dielectric material used in microelectronic applications. However, a shortcoming of the material is its low T_g, at about 140 °C. A second ACS zwitterion, 1,1′‐[fluorenylidenebis(6‐hydroxy‐3,1‐phenylene)] bis(tetrahydrothiophenium hydroxide) bis(inner salt) (2) was prepared that yields a crosslinked polymer with a higher T_g of about 190 °C. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1283–1290, 2000     

Three-component coupling polymerization of bisallene,aryl dihalides,and nucleophiles via π-allylpalladium complex. II. Effect of nucleophiles on polymerization

A novel palladium-catalyzed three-component polycondensation of 1,2,10,11-dodecatetraene, 4,4′-diiodobiphenyl, and nucleophiles was carried out using various carbanions and amines as a nucleophilic part. The polymerization with various sodium diethyl malonates produced polymers in high yields. Particularly, no exo-double bond was detected in the polymers prepared from sodium diethyl malonates bearing substituents directly on the carbanion center. The ratios of E- and Z- isomeric units in the polymers were dependent on the structure of the nucleophiles used. Other carbanions with appropriate electron-withdrawing groups such as sulphones and ketones can be also used as a nucleophile for the present polycondensation. Within heteronucleophiles examined, cyclic amines were suitable to produce polymers in high yields. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1211–1218, 1997     

用AMI方法确定杀虫单合成过程的中间体

一水合二甲基—氢代—2—(1,3一二磺酸单钠硫代丙基)铵是我国开发成功的一种仿生性沙蚕毒系的新杀虫剂,商品名为杀虫单[J]。农业上有广泛的用途。其结构式为:     

Silyldefluorination of Fluoroarenes by Concerted Nucleophilic Aromatic Substitution

The reaction of readily generated silyl lithium reagents with various aryl fluorides to provide the corresponding aryl silanes is reported. DFT calculations reveal that the nucleophilic aromatic substitution of the fluoride anion by the silyl lithium reagent proceeds through concerted ipso substitution. In contrast to the classical nucleophilic aromatic substitution, this concerted ionic silyldefluorination also occurs on more electron‐rich aryl fluorides.     

Synthesis of polycarbosilanes having a five‐membered cyclic carbonate structure and their application to prepare gel polymer electrolytes for lithium ion batteries

A silacyclobutane having a five‐membered cyclic carbonate structure (SBMC) was prepared, and its transition metal‐catalyzed ring‐opening polymerization at the four‐membered carbosilane unit was investigated as well as formation of carbosilane networked polymers and polymer gel electrolytes. The SBMC was synthesized by epoxidation of 1‐(4‐butenyl)‐1‐methylsilacyclobutane followed by insertion of CO₂ to the epoxide. Ring‐opening polymerization of the silacyclobutane moiety in the SBMC readily proceeded by a transition metal catalyst such as platinum divinyltetramethyldisiloxane complex. A flexible networked polymer film was obtained by copolymerization of the SBMC with a small amount of crosslinker, hexamethylene‐1,6‐bis(1‐methylsilacyclobutane) (HMBS). The copolymerization of SBMC and HMBS in 1 M LiPF₆ solution in ethylene carbonate and diethyl carbonate (3/7 v/v) gave a gel polymer electrolyte, which showed good ionic conductivity and could be applied to lithium ion batteries. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Chemoselectivity Control in the Reactions of 1,2‐Cyclic Sulfamidates with Amines

Although 1,2‐cyclic sulfamidates derived from α‐methylisoserine undergo nucleophilic displacement at the quaternary center, to the best of our knowledge their behavior with amines as nucleophiles has never been explored. We have found that a broad range of amines can be used, demonstrating the scope of the reaction, and that excellent control of the chemoselectivity can be achieved. Application of this methodology for the synthesis of a chiral α,β‐diamino acid and an important piperazinone heterocycle is also presented. Additionally, we have found that DMF and DMSO behave not only as polar aprotic solvents but also as O‐nucleophilic reagents, allowing the incorporation of an oxygen atom at a quaternary center of the electrophile, with inversion of configuration.