Forgotten monomers: access to α‐modified N‐vinylpyrrolidone polymers via C‐alkylation

Alkylation of N‐vinylpyrrolidone using lithium diisopropylamide and bis(2‐bromoethyl) ether was carried out to obtain 3‐(2‐(2‐bromoethoxy)ethyl)‐1‐vinyl‐2‐pyrrolidone ( 2 ). The derivative 2 represents a versatile starting molecule for further modification via nucleophilic displacement yielding, for example, the bicyclic 2‐vinyl‐8‐oxa‐2‐azaspiro[4.5]decan‐1‐one ( 4 ) or the ammonium salt 3‐diethoxy‐N,N′‐((dimethylbenzyl)ammonium bromide)‐1‐vinyl‐2‐pyrrolidone ( 10 ). Via free radical polymerization of 4 and 10 , the corresponding homopolymers were obtained. Copolymerization of 4 and 10 with N,N′‐diethylacrylamide yielded water‐soluble materials. The thermosensitive solubility of copolymers poly[(2‐vinyl‐8‐oxa‐2‐azaspiro[4.5]decan‐1‐one)‐co‐(N,N′‐diethylacrylamide)] and poly[(3‐diethoxy‐N,N′‐((dimethylbenzyl)ammonium bromide)‐1‐vinyl‐2‐pyrrolidone)‐co‐(N‐vinylpyrrolidone)] in water was investigated. © 2015 Society of Chemical Industry     

Highly Efficient and Enantioselective Iridium‐Catalyzed Asymmetric Hydrogenation of N‐Arylimines

A catalytic method employing the cationic iridium‐(S_c,R_p)‐DuanPhos [(1R,1′R,2S,2′S)‐2,2′‐di‐tert‐butyl‐2,2′,3,3′‐tetrahydro‐1H,1′H‐1,1′‐biisophosphindole] complex and BARF {tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate} counterion effectively catalyzes the enantioselective hydrogenation of acyclic N‐arylimines with high turnover numbers (up to 10,000 TON) and excellent enantioselectivities (up to 98% ee), achieving the practical synthesis of chiral secondary amines.     

Synthesis and structural characterization of novel chiral nanostructured poly(esterimide)s containing different natural amino acids and 4,4′‐thiobis(2‐tert‐butyl‐5‐methylphenol) linkages

Pyromellitic dianhydride (benzene‐1,2,4,5‐tetracarboxylic dianhydride) (1) was reacted with several amino acids in acetic acid and the resulting imide‐acid [N,N′‐(pyromellitoyl)‐bis‐L ‐amino acid diacid] (4a–4d) was obtained in high yield. The direct polycondensation reaction of these diacids with 4,4′‐thiobis(2‐tert‐butyl‐5‐methylphenol) (5) was carried out in a system of tosyl chloride(TsCl), pyridine, and N,N‐dimethyl formamide (DMF) to give a series of novel optically active poly(esterimide)s. Step‐growth polymerization was carried out by varying the time of heating and the molar ratio of TsCl/diacid, and the optimum conditions were achieved. These new chiral polymers were characterized with respect to chemical structure and purity by means of specific rotation experiments, FTIR, ¹H‐NMR, X‐ray diffraction, elemental, and thermogravimetric analysis (TGA) field emission scanning electron microscopy (FE‐SEM) techniques. These polymers are readily soluble in many polar organic solvents like DMF, N,N‐dimethyl acetamide, dimethyl sulfoxide, N‐methyl‐2‐pyrrolidone, and protic solvents such as sulfuric acid. TGA showed that the 10% weight loss temperature in a nitrogen atmosphere was more than 390°C; therefore, these new chiral polymers have useful levels of thermal stability associated with good solubility. Furthermore, study of the surface morphology of the obtained polymers by FE‐SEM showed that each polymers exhibit nanostructure morphology. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Efficient Inhibition of Telomerase by Nickel–Salophen Complexes

Four nickel(II)–salophen complexes containing alkyl‐imidazolium chains connected at the ortho or meta positions were prepared: N,N′‐bis(2‐hydroxy‐4‐methyl‐3H‐imidazol‐1‐iumbenzylideneamino)phenylenediamine ( 1 ), N,N′‐bis(2‐hydroxy‐3‐methyl‐3H‐imidazol‐1‐iumbenzylideneamino)phenylenediamine ( 2 ), N,N′‐bis(2‐hydroxy‐3‐methyl‐3H‐imidazol‐1‐iumbenzylideneamino)methyl‐3H‐imidazol‐1‐iumphenylenediamine ( 3 ), and N,N′‐bis(2‐hydroxy‐4‐methyl‐3H‐imidazol‐1‐iumbenzylideneamino)methyl‐3H‐imidazol‐1‐iumphenylenediamine ( 4 ). They protect G‐quadruplex DNA (G₄‐DNA) against thermal denaturation and show K_A values in the range of 7.4×10⁵ to 4×10⁷ m ^?1 for G₄‐DNA models. Complex 4 exhibits an IC₅₀ value of 70 nm for telomerase inhibition.     

Highly trans‐1,4‐specific polymerization of 1,3‐butadiene catalyzed by [2,6‐bis{(4S)‐ (−)‐isopropyl‐2‐oxazolin‐2‐yl}pyridine] chromium complex activated with modified methylaluminoxane

Chromium complexes with N,N,N‐tridentate ligands, LCrCl₃ (L = 2,6‐bis{(4S)‐(?)‐isopropyl‐2‐oxazolin‐2‐yl}pyridine ( 1 ), 2,2′:6′,2″‐terpyridine ( 2 ), and 4,4′,4″‐tri‐tert‐butyl‐2,2′:6′,2″‐terpyridine ( 3 )), were prepared. The structures of 1 and 2 were determined by X‐ray crystallography. Upon activation with modified methylaluminoxane (MMAO), 1 catalyzed the polymerization of 1,3‐butadiene, while 2 and 3 was inactive. The obtained poly(1,3‐butadiene) obtained with 1 ‐MMAO was found to have completely trans‐1,4 structure. The 1 ‐MMAO system also showed catalytic activity for the polymerization of isoprene to give polyisoprene with trans‐1,4 (68%) and cis‐1,4 (32%) structure. Copyright © 2011 Society of Chemical Industry     

Arylamine polymers prepared via facile paraldehyde addition condensation: an effective hole‐transporting material for perovskite solar cells

Arylamine polymers were prepared via the facile one‐step addition condensation of N,N′‐diphenyl‐N,N′‐bis(4‐methylphenyl)‐1,4‐phenylenediamine and 4‐methoxytriphenylamine with paraldehyde. The polymers were highly soluble in common organic solvents. The non‐conjugated arylamine polymer structure was characterized and found to form tough, homogeneous, amorphous layers with a glass transition temperature above 200 °C on a substrate by a simple spin‐coating process. The polymer layers exhibited a hole mobility of the order of 10^?5 cm² V^?1 s^?1, which was comparable with those of previously reported arylamine polymers, and a highest occupied molecular orbital level of ?5.38 eV appropriate for the hole‐transporting layer of perovskite solar cells. The perovskite cells fabricated with the polymers gave a photovoltaic conversion efficiency of 16.0%. © 2018 Society of Chemical Industry     

Effects of phenolic antioxidants on ultrahigh molecular weight polyethylene/decalin solution

The degradation of ultrahigh molecular weight polyethylene (UHMW‐PE) during its dissolution into decalin is discussed. The stabilization of the solution by three phenolic antioxidants, octadecyl β‐(3,5‐di‐tert‐butyl‐4‐hydroxyphenyl)propionate (1076), tetrakis[methylene‐β‐(3,5‐di‐tert‐butyl‐4‐hydroxyphenyl)propionate]methane (1010), and 1,1,3‐tris(2‐methyl‐4‐hydroxy‐5‐tert‐butylphenyl)butane (CA), and an auxiliary antioxidant, dilaurylthiodipropionate (DLTP) is also discussed. Among the three phenolic antioxidants, 1076 had the greatest effect. The auxiliary antioxidant was effective in stabilizing the solution when combined with one of the three phenolic antioxidants. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2877–2881, 2000     

Monomers and polymers of 4‐(N,N‐diallylamino)pyridine functions

4‐(N,N‐Diallylamino)pyridine (DAAP), N,N‐diallylaminobenzene (DAAB), N,N,N′,N′‐tetrallyl‐4,4′‐diaminobenzidine (AAB), N,N,N′,N′‐tetrallyl‐4,4′‐diaminodiphenyl sulfone (AABS), and N,N,N′,N′‐tetrallyl‐4,4′‐diaminodiphenyl ether (AABE) were prepared by sodium substitution and N‐allylation. Moreover, linear polyDAAP, poly(DAAP‐co‐DAAB), and network poly(DAAP‐co‐AAB), poly(DAAP‐co‐AABS), and poly(DAAP‐co‐AABE), all being polymers containing supernucleophilic groups, were synthesized in the cyclopolymerization. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 363–367, 2000     

Antioxidant mechanism of a 3‐arylbenzofuranone containing a 2′‐hydroxyl group

5‐Methyl‐7‐tert‐butyl‐3‐(2′hydroxyl‐5′‐methylphenyl)3H‐benzofuran‐2‐one (PCRBF2), is a better scavenger of 2,2‐diphenyl‐1‐picrylhydrazyl radicals than benzofuranone analogs without the 2′‐substituent, which indicates that PCRBF2 will cause good stabilization in polymers. To prove this further, antioxidation by PCRBF2 and other benzofuranone analogs, namely, 5‐methyl‐7‐tert‐butyl‐3‐(3′,4′‐dimethylphenyl)3H‐benzofuran‐2‐one (OXBF2) and 5‐methyl‐7‐tert‐butyl‐3‐(2′,5′‐dimethylphenyl)3H‐benzofuran‐2‐one (PXBF2), was comparatively studied in polypropylene. The resulting antioxidant activity order of these benzofuranones was PCRBF2 > OXBF2 > PXBF2, an observation showing that the hydroxyl group in the 2′‐position does not weaken the antioxidant activity of benzofuranone, but, on the contrary, increases it. Analyses by FTIR revealed intramolecular hydrogen bonding between the 3‐position hydrogen and the oxygen of the 2′‐hydroxyl group, which makes the 2′‐hydroxyl hydrogen of PCRBF2 more reactive than the 3‐position reactive hydrogen. Thus the hydroxyl group reacts with radicals first. J. VINYL ADDIT. TECHNOL., 19:198‐202, 2013. © 2013 Society of Plastics Engineers     

Crosslinking of 1,9‐bis[glycidyloxypropyl]penta‐ (1′H,1′H,2′H,2′H‐perfluoroalkylmethylsiloxane)s with α,ω‐diaminoalkanes: The cure behavior and film properties

A series of nine films were prepared via phenol‐catalyzed thermal crosslinking reactions of 1,9‐bis‐ [glycidyloxypropyl]pentasiloxanes {1,9‐bis[glycidyloxypro‐ pyl]decamethylpentasiloxane (I), 1,9‐bis[glycidyloxypropyl]‐3,5,7‐tris(3′,3′,3′‐trifluoropropyl)heptamethylpentasiloxane (II), and 1,9‐bis[glycidyloxypropyl]‐3,5,7‐tris(1′H,1′H,2′H, 2′H‐perfluorooctyl)heptamethylpentasiloxane (III)} with α,ω‐diaminoalkanes [1,6‐diaminohexane (a), 1,8‐diaminooctane (b), and 1,12‐diaminododecane (c)]. The crosslink density was controlled by the choice of a–c. The cure behavior of I–III with a–c was studied with differential scanning calorimetry. The mechanical properties of the films were determined by dynamic mechanical thermal analysis. Their thermal stability was analyzed by thermogravimetric analysis. The surface properties of the films were evaluated with static contact‐angle measurements. These films represented a novel class of epoxies with an unusual combination of properties: high flexibility (low glass‐transition temperature), good thermal stability, and hydrophobic surfaces. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 203–210, 2004     

N,N′‐Dioxide‐Magnesium Ditriflate Complex‐Catalyzed Asymmetric α‐Hydroxylation of β‐Keto Esters and β‐Keto Amides

The highly catalytic asymmetric α‐hydroxylation of 1‐tetralone‐derived β‐keto esters and β‐keto amides using tert‐butyl hydroperoxide (TBHP) as the oxidant was realized by a chiral N,N′‐dioxide‐magnesium ditriflate [Mg(OTf)₂] complex. A series of corresponding chiral α‐hydroxy dicarbonyl compounds was obtained in excellent yields (up to 99%) with excellent enantioselectivities (up to 98% ee). The products were easily transformed into useful building blocks and the precursor of daunomycin was achieved in an asymmetric catalytic way for the first time.     

Thermal and Mechanical Properties of Poly(arylene ether ketone)s Based on 5‐tert‐Butyl‐1,3‐bis(4‐fluorobenzoyl)benzene

An aromatic bishalide, 5‐tert‐butyl‐1,3‐bis(4‐fluorobenzoyl)benzene ( 2 ) was synthesized in high yield and purity by the reaction of 5‐tert‐butylisophthaloyl chloride ( 1 ) and fluorobenzene and polymerized by nucleophilic substitution reaction with commercially available aromatic bisphenols to prepare a series of high molecular weight poly(arylene ether ketone)s containing pendant tertiary butyl groups. The effect of molecular structure on the physical, thermal, mechanical and adhesion properties of the polymers was investigated.     

Highly Enantioselective Phase‐Transfer Catalytic α‐Alkylation of α‐tert‐Butoxycarbonyllactams: Construction of β‐Quaternary Chiral Pyrrolidine and Piperidine Systems

A new enantioselective α‐alkylation of α‐tert‐butoxycarbonyllactams for the construction of β‐quaternary chiral pyrrolidine and piperidine core systems is reported. α‐Alkylations of N‐methyl‐α‐tert‐butoxycarbonylbutyrolactam and N‐diphenylmethyl‐α‐tert‐butoxycarbonylvalerolactam under phase‐transfer catalytic conditions (solid potassium hydroxide, toluene, −40 °C) in the presence of (S,S)‐3,4,5‐trifluorophenyl‐3,3′,5,5′‐tetrahydro‐2,6‐bis(3,4,5‐trifluorophenyl)‐4,4′‐spirobi[4H‐dinaphth[2,1‐c:1′,2′‐e]azepinium] bromide [(S,S)‐NAS Br] (5 mol%) afforded the corresponding α‐alkyl‐α‐tert‐butoxycarbonyllactams in very high chemical (up to 99%) and optical yields (up to 98% ee). Our new catalytic systems provide attractive synthetic methods for pyrrolidine‐ and piperidine‐based alkaloids and chiral intermediates with β‐quaternary carbon centers.     

Synthesis and properties of novel aromatic polyamides derived from 2,2‐bis[4‐(4‐amino‐2‐fluorophenoxy) phenyl]hexafluoropropane and aromatic dicarboxylic acids

A series of polyamides were synthesized by the direct polycondensation of 2,2‐bis[4‐(4‐amino‐2‐fluorophenoxy)phenyl]hexafluoropropane with various commercially available dicarboxylic acids such as terephthalic acid, isophthalic acid, 5‐t‐butyl isophthalic acid, and 2,6‐naphthalene dicarboxylic acid. The synthesized polyamides were soluble in several organic solvents such as N,N‐dimethylformamide, N,N‐dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, and chloroform, and they exhibited inherent viscosities of 0.42–0.59 dL/g. The polyamides exhibited weight‐average molecular weights of up to 26,000, which depended on the exact repeating unit structure. These polyamides showed good thermal stability up to 440°C for a 10% weight loss in synthetic air. The polyamides synthesized from 5‐t‐butyl isophthalic acid and isophthalic acid exhibited glass‐transition temperatures of 217 and 185°C, respectively (by differential scanning calorimetry) in nitrogen. The polyamides synthesized from terephthalic acid and 2,6‐naphthalene dicarboxylic acid showed melting temperatures of 319 and 385°C, respectively. The polyamides films were pale yellow, with tensile strengths of up to 82 MPa, moduli of elasticity of up to 2.3 GPa, and elongations at break of up to 9%, which depended on the exact repeating unit structure. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 691–696, 2003     

Asymmetric Aerobic Oxidation of α‐Hydroxy Acid Derivatives Catalyzed by Reusable,Polystyrene‐Supported Chiral N‐Salicylidene Oxidovanadium tert‐Leucinates

The direct immobilization of two different C‐5‐propargyl ether‐modified, chiral N‐salicylidene vanadyl(V) tert‐leucinates onto 4‐azidomethyl‐substituted polystyrene by click chemistry was examined. Among the eight different solvents investigated, the resulting polystyrene‐supported catalysts promote the asymmetric, aerobic oxidation of α‐hydroxy (thio)esters and amides with enantioselectivities of up to 99% ee (selectivity factor up to 41) in chloroform. These polystyrene‐supported catalysts can be readily recovered by filtration and reused for at least four consecutive runs without discernible loss of reactivity and enantioselectivity.     

Atom transfer radical polymerization of methylmethacrylate and styrene initiated by 3,5‐bis(perfluorobenzyloxy)benzyl 2‐bromopropanoate

The synthesis of polymethylmethacrylate (pMMA) and polystyrene (pSt) were realized with newly synthesized initiator, 3,5‐bis(perfluorobenzyloxy)benzyl 2‐bromopropanoate (FBr) in the presence of copper bromide (CuBr) and N,N,N′,N″,N″‐pentamethyl‐diethylenetriamine (PMDETA) by using atom transfer radical polymerization (ATRP). The perfluorinated aromatic group containing initiator was prepared by esterification of the (3,5‐bis[(perfluorobenzyl)oxy]‐phenyl alcohol. Both initiator and polymers were characterized by ¹H‐NMR spectroscopy, gel permeation chromatography, differential scanning calorimetry, and thermogravimetric analysis. The ATRP was supported by an increase in the molecular weight of the forming polymers and also by their monomodal molecular weight distribution. Contact angle measurements of water and ethylene glycol on films of synthesized polymers indicated higher degree of hydrophobicity than that of pure pMMA and pure pSt. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

New polyamides based on 2,5‐bis[(4‐carboxyanilino) carbonyl] pyridine and aromatic diamines: Synthesis and characterization

Seven new polyamides 6a–g were synthesized through the direct polycondensation reaction of 2,5‐bis[(4‐carboxyanilino) carbonyl] pyridine 4 with seven derivatives of aromatic diamines 5a–g in a medium consisting of N‐methyl‐2‐pyrrolidone, triphenyl phosphite, calcium chloride, and pyridine. The polycondensation reaction produced a series of novel polyamides containing pyridyl moiety in the main chain in high yield with inherent viscosities between 0.32 – 0.72 dL/g. The resulted polymers were fully characterized by means of FTIR spectroscopy, elemental analyses, inherent viscosity, and solubility tests. Thermal properties of these polymers were investigated by using thermal gravimetric analysis and differential thermal gravimetric. All the polymers were soluble at room temperature in polar solvents, such as N,N‐dimethyl acetamide, N,N‐dimethyl formamide, dimethyl sulfoxide, and N‐methyl‐2‐pyrrolidone. 2,5‐Bis[(4‐carboxyanilino) carbonyl] pyridine 4 as a new monomer containing pyridyl moiety was synthesized by using a two‐step reaction. At first 2,5‐pyridine dicarboxylic acid 1 was converted to 2,5‐pyridine dicarbonyl dichloride 2 . Then diacid 4 was prepared by condensation reaction of diacid chloride 2 with p‐aminobenzoic acid 3. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Thermal Stability of Polymer Additives: Comparison of Decomposition Models Including Oxidative Pyrolysis

The thermo‐oxidative stability of widely used polymer additives has been investigated. A comparative analytical approach with classic and innovative decomposition models for polymer additives was conducted and the results supported using quantum‐chemical calculations. Unique pyrolysis products of the analytes were compiled utilizing pyrolysis online coupled to gas chromatography followed by mass spectrometric detection (Pyr‐GC–MS). The pyrolysis was either performed under inert conditions or in an oxygen‐containing atmosphere. Squalane was applied as polymer‐mimicking liquid next to low density polyethylene (LDPE) and polyamide 6 (PA 6) as matrices for 10 selected additives. The additives included in this study range from antioxidants and plasticizers to processing aids. These were selected to address a range of application in consumer products and to cover different chemical classes. The toxicological relevance of additives and potential breakdown products was considered. Consequently, degradation of sterically hindered antioxidants, diarylamines, and a trimellitic acid derivative was investigated. The findings were used to predict the behavior of consumer products made of polymeric materials entailing additives. The level of Antioxidant 2246 [2‐tert‐butyl‐6‐[(3‐tert‐butyl‐2‐hydroxy‐5‐methylphenyl)methyl]‐4‐methylphenol] and one of its predicted decomposition products was determined in baby bottle nipples made of natural rubber [2‐tert‐butyl‐4‐methylphenol] utilizing the complementary technique of gas chromatography coupled to tandem mass spectrometry (GC–MS/MS). This study provides a comprehensive characterization of important polymer additives and enables the prioritization of degradation products for further risk assessment. J. VINYL ADDIT. TECHNOL., 25:E12–E27, 2019. © 2018 The Authors. Journal of Vinyl and Additive Technology published by Wiley Periodicals, Inc. on behalf of Society of Plastics Engineers     

Synthesis,characterization, and applications of novel additives of polysiloxane containing N,N′‐bis(diphenylsilyl)tetraphenylcyclodisilazane

Three N,N′‐bis(diphenylsilyl)tetraphenylcyclodisilazane‐based derivatives, N,N′‐bis(3,3,3‐trimethyl‐1,1‐diphenyl‐disiloxanyl)tetraphenylcyclodisilazane, N‐(3,3‐dimethyl‐1,1‐diphenyl‐3‐vinyl‐disiloxanyl)‐N′‐(3,3,3‐trimethyl‐1,1‐diphenyl‐disiloxanyl)‐tetraphenylcyclodisilazane, and N,N′‐bis‐(3,3‐dimethyl‐1,1‐diphenyl‐3‐vinyl‐disiloxanyl) tetraphenylcyclodisilazane, were synthesized. These compounds were synthesized in an easy and effective route. X‐ray single‐crystal diffraction analyses showed that the four‐member rings were planar rings, and the structures are different with the different substitution. The compound N,N′‐bis‐(3,3‐dimethyl‐1,1‐diphenyl‐3‐vinyl‐disiloxanyl) tetraphenylcyclodisilazane was added to the silicone rubber as additive to enhance the thermal stability greatly increased the thermal stability of the silicone rubber, without altering the glass transition temperature. The weight loss at 350°C in nitrogen atmosphere for 24 h reduced from 55.8% for 0 wt % to 9.8% for 10 wt % addition N,N′‐Bis‐(3,3‐dimethyl‐1,1‐diphenyl‐3‐vinyl‐disiloxanyl)tetraphenylcyclodisilazane. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Highly Enantioselective Synthesis of 3‐Hydroxy‐2‐methylpropanoic Acid Esters through Ruthenium‐SYNPHOS®‐Catalyzed Hydrogenation: Useful Building Blocks for the Synthetic Community

Both enantiomers of 3‐hydroxy‐2‐methylpropanoic acid tert‐butyl ester were prepared with high enantioselectivity (up to 94 %) through a ruthenium‐SYNPHOS®‐promoted asymmetric hydrogenation reaction using an atom‐economic transformation from simple and inexpensive precursors.