Phosphorus‐containing epoxy resins: Thermal characterization

Three novel aromatic phosphorylated diamines, i.e., bis N,N′‐{3‐[(3‐aminophenyl)methyl phosphinoyl] phenyl} pyromellitamic acid (AP), 4,4′‐oxo bis N,N′‐{3‐[(3‐aminophenyl)methyl phosphinoyl] phenyl}phthalamic acid (AB) and 4,4′‐hexafluoroisopropylidene‐bis N,N′‐{3‐[(3‐aminophenyl)methyl phosphinoyl] phenyl}phthalamic acid (AF) were synthesized and characterized. These amines were prepared by solution condensation reaction of bis(3‐aminophenyl)methyl phosphine oxide (BAP) with 1,2,4,5‐benzenetetracarboxylic acid anhydride (P)/3,3′,4,4′‐benzophenonetetracarboxylic acid dianhydride (B)/4,4′‐(hexafluoroisopropylidene)diphthalic acid anhydride (F), respectively. The structural characterization of amines was done by elemental analysis, DSC, TGA, ¹H‐NMR, ¹³C‐NMR and FTIR. Amine equivalent weight was determined by the acetylation method. Curing of DGEBA in the presence of phosphorylated amines was studied by DSC and curing exotherm was in the temperature range of 195–267°C, whereas with conventional amine 4,4′‐diamino diphenyl sulphone (D) a broad exotherm in temperature range of 180–310°C was observed. Curing of DGEBA with a mixture of phosphorylated amines and D, resulted in a decrease in characteristic curing temperatures. The effect of phosphorus content on the char residue and thermal stability of epoxy resin cured isothermally in the presence of these amines was evaluated in nitrogen atmosphere. Char residue increased significantly with an increase in the phosphorus content of epoxy network. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2235–2242, 2002     

Enantioselective Synthesis of (−)‐CP‐55940 via Ruthenium‐ Catalyzed Asymmetric Hydrogenation of Ketones

A new and efficient catalytic asymmetric synthesis of the potent cannabinoid receptor agonist (−)‐CP‐55940 has been developed by using ruthenium‐catalyzed asymmetric hydrogenation of racemic α‐aryl ketones via dynamic kinetic resolution (DKR) as a key step. With RuCl₂‐SDPs/diamine [SDPs=7,7′‐bis(diarylphophino)‐1,1′‐spirobiindane] catalysts the asymmetric hydrogenation of racemic α‐arylcyclohexanones via DKR provided the corresponding cis‐β‐arylcyclohexanols in high yields with up to 99.3% ee and >99:1 cis‐selectivities. Both ethylene ketal group at the cyclohexane ring and ortho‐methoxy group at the phenyl ring of the substrates 6 have little effect on the selectivity and reactivity of the hydrogenations. Based on this highly efficient asymmetric ketone hydrogenation, (−)‐CP‐55940 was synthesized in 13 steps (the longest linear steps) in 14.6% overall yield starting from commercially available 3‐methoxybenzaldehyde and 1,4‐cyclohexenedione monoethylene acetal.     

Resistive switching characteristics of polyimides derived from 2,2′‐aryl substituents tetracarboxylic dianhydrides

2,2′‐Position aryl‐substituted tetracarboxylic dianhydrides including 2,2′‐bis(biphenyl)‐4,4′,5,5′‐biphenyl tetracarboxylic dianhydride and 2,2′‐bis[4‐(naphthalen‐1‐yl)phenyl)]‐4,4′,5,5′‐biphenyl tetracarboxylic dianhydride were synthesized. A new series of aromatic polyimides (PIs) were synthesized via a two‐step procedure from 3,3′,4,4′‐biphenyl tetracarboxylic dianhydride and the newly synthesized tetracarboxylic dianhydrides monomers reacting with 2,2′‐bis[4′‐(3″,4″,5″‐trifluorophenyl)phenyl]‐4,4′‐biphenyl diamine. The resulting polymers exhibited excellent organosolubility and thermal properties associated with T_g at 264 °C and high initial thermal decomposition temperatures (T_5%) exceeding 500 °C in argon. Moreover, the fabricated sandwich structured memory devices of Al/PI‐a/ITO was determined to present a flash‐type memory behaviour, while Al/PI‐b/ITO and Al/PI‐c/ITO exhibited write‐once read‐many‐times memory capability with different threshold voltages. In addition, Al/polymer/ITO devices showed high stability under a constant stress or continuous read pulse voltage of ? 1.0 V. Copyright © 2011 Society of Chemical Industry     

The preparation of α‐bis and α,ω‐tetrakis aromatic oxazolyl‐ and carboxyl‐functionalized polymers using 1,1‐bis[4‐(2‐(4,4‐dimethyl‐1,3‐oxazolyl))phenyl]ethylene in atom transfer radical polymerization reactions

The preparation of new compounds, 1,1‐bis[4‐(2‐(4,4‐dimethyl‐1,3‐oxazolyl))phenyl]ethanol and a new symmetrically disubstituted 1,1‐diphenylethylene derivative, 1,1‐bis[4‐(2‐(4,4‐dimethyl‐1,3‐oxazolyl))phenyl]ethylene, is described. 1,1‐Bis[4‐(2‐(4,4‐dimethyl‐1,3‐oxazolyl))phenyl]ethylene was utilized as a dioxazolyl initiator precursor for the polymerization of styrene by atom transfer radical polymerization (ATRP) methods to produce α‐bis(oxazolyl) polystyrene. The kinetic study of the polymerization process indicated that the free radical polymerization reaction for the preparation of α‐bis(oxazolyl) polystyrene follows first‐order rate kinetics with respect to monomer consumption. α,ω‐Tetrakis(oxazolyl) polystyrene was prepared by a new, in situ, controlled/living, post‐ATRP chain‐end‐functionalization reaction which involves the direct addition of 1,1‐bis[4‐(2‐(4,4‐dimethyl‐1,3‐oxazolyl))phenyl]ethylene to the ω‐terminus of the α‐bis(oxazolyl) polystyrene derivative, without the isolation and purification of the polymeric precursor. α‐Bis(carboxyl) and α,ω‐tetrakis(carboxyl) polystyrene derivatives were obtained by the quantitative chemical transformation of the oxazoline groups of the respective aromatic oxazolyl chain‐end‐functionalized polystyrene derivatives to the aromatic carboxyl groups. The organic precursor compounds, the dioxazolyl‐functionalized 1,1‐diphenylethylene derivative and the functionalized polymers were characterized using ¹H NMR and ¹³C NMR spectrometry and Fourier transform infrared spectroscopy, size‐exclusion and thin‐layer chromatography and non‐aqueous titration measurements. © 2014 Society of Chemical Industry     

Organosoluble polyimides derived from asymmetric 2‐substituted‐and 2,2′,6‐trisubstituted‐4,4′‐oxydianilines

We report a new method for the preparation of asymmetric diamines using 4,4′‐oxydianiline (4,4′‐ODA) as the starting material. By controlling the equivalents of bromination agent, N‐bromosuccinimide, we were able to attach bromide and phenyl substituents at the 2‐ or 2,2′,6‐positions of 4,4′‐ODA. Thus, four new asymmetric aromatic diamines, 2‐bromo‐4,4′‐oxydianiline (6), 2,2′,6‐tribromo‐4,4′‐oxydianiline (7), 2‐phenyl‐4,4′‐oxydianiline (8) and 2,2′,6‐triphenyl‐4,4′‐oxydianiline (9), were synthesized by this method. Their structural asymmetry was confirmed using ¹H NMR spectroscopy. Asymmetric polyimides (PI10–PI13) were prepared from these diamines and three different dianhydrides (pyromellitic dianhydride (PMDA), 3,3′,4,4′‐biphenyltetracarboxylic dianhydride and 2,2‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride) in refluxing m‐cresol. The formed polyimides, except PI10a derived from 6 and PMDA, were all soluble in m‐cresol without premature precipitation during polymerization. These polyimides with inherent viscosity of 0.41–0.96 dL g^?1, measured at a concentration of 0.5 g dL^?1 in N‐methyl‐2‐pyrrolidone at 30 °C, can form tough and flexible films. Because of the structural asymmetry, they also exhibited enhanced solubility in organic solvents. Especially, polyimides PI11a and PI13a derived from 7 and 9 with rigid PMDA were soluble in various organic solvents at room temperature. The structural asymmetry of the prepared polyimides was also evidenced from ¹H NMR spectroscopy. In the ¹H NMR spectrum of PI11a, the protons of pyromellitic moiety appeared in an area ratio of 1:2:1 at three different chemical shifts, which were assigned to head‐to‐head, head‐to‐tail and tail‐to‐tail configurations, respectively. These polyimides also exhibited good thermal stability. Their glass transition temperatures ranged from 297 to 344 °C measured using thermal mechanical analysis. © 2013 Society of Chemical Industry     

α‐Bis and α,ω‐tetrakis(4‐dimethylaminophenyl) functionalized polymers by atom transfer radical polymerization using 1,1‐bis[(4‐dimethylamino)phenyl]ethylene as tertiary diamine initiator precursor and functionalizing agent

The quantitative syntheses of α‐bis and α,ω‐tetrakis tertiary diamine functionalized polymers by atom transfer radical polymerization (ATRP) methods are described. A tertiary diamine functionalized 1,1‐diphenylethylene derivative, 1,1‐bis[(4‐dimethylamino)phenyl]ethylene (1), was evaluated as a unimolecular tertiary diamine functionalized initiator precursor as well as a functionalizing agent in ATRP reactions. The ATRP of styrene, initiated by a new tertiary diamine functionalized initiator adduct (2), affords the corresponding α‐bis(4‐dimethylaminophenyl) functionalized polystyrene (3). The tertiary diamine functionalized initiator adduct (2) was prepared in situ by the reaction of (1‐bromoethyl)benzene with 1,1‐bis[(4‐dimethylamino)phenyl]ethylene (1) in the presence of a copper (I) bromide/2,2′‐bipyridyl catalyst system. The ATRP of styrene proceeded via a controlled free radical polymerization process to afford quantitative yields of the corresponding α‐bis(4‐dimethylaminophenyl) functionalized polystyrene derivative (3) with predictable number‐average molecular weight (M_n) and narrow molecular weight distribution (M_w/M_n) in a high initiator efficiency reaction. The polymerization process was monitored by gas chromatography analysis. Quantitative yields of α,ω‐tetrakis(4‐dimethylaminophenyl) functionalized polystyrene (4) were obtained by a new post ATRP chain end modification reaction of α‐bis(4‐dimethylaminophenyl) functionalized polystyrene (3) with excess 1,1‐bis[(4‐dimethylamino)phenyl]ethylene (1). The tertiary diamine functionalized initiator precursor 1,1‐bis[(4‐dimethylamino)phenyl]ethylene (1) and the different tertiary amine functionalized polymers were characterized by chromatography, spectroscopy and non‐aqueous titration measurements. Copyright © 2012 Society of Chemical Industry     

Synthesis and characterization of organosoluble and transparent polyimides derived from trans‐1,2‐bis(3,4‐dicarboxyphenoxy)cyclohexane dianhydride

A novel dianhydride, trans‐1,2‐bis(3,4‐dicarboxyphenoxy)cyclohexane dianhydride (1,2‐CHDPA), was prepared through aromatic nucleophilic substitution reaction of 4‐nitrophthalonitrile with trans‐cyclohexane‐1,2‐diol followed by hydrolysis and dehydration. A series of polyimides (PIs) were synthesized from one‐step polycondensation of 1,2‐CHDPA with several aromatic diamines, such as 2,2′‐bis(trifluoromethyl)biphenyl‐4,4′‐diamine (TFDB), bis(4‐amino‐2‐trifluoromethylphenyl)ether (TFODA), 4,4′‐diaminodiphenyl ether (ODA), 1,4‐bis(4‐aminophenoxy)benzene (TPEQ), 4,4′‐(1,3‐phenylenedioxy)dianiline (TPER), 2,2′‐bis[4‐(3‐aminodiphenoxy)phenyl]sulfone (m‐BAPS), and 2,2′‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]sulfone (6F‐BAPS). The glass transition temperatures (T_gs) of the polymers were higher than 198°C, and the 5% weight loss temperatures (T_d5%s) were in the range of 424–445°C in nitrogen and 415–430°C in air, respectively. All the PIs were endowed with high solubility in common organic solvents and could be cast into tough and flexible films, which exhibited good mechanical properties with tensile strengths of 76–105 MPa, elongations at break of 4.7–7.6%, and tensile moduli of 1.9–2.6 GPa. In particular, the PI films showed excellent optical transparency in the visible region with the cut‐off wavelengths of 369–375 nm owing to the introduction of trans‐1,2‐cyclohexane moiety into the main chain. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42317.     

Curing kinetics and thermal properties of diglycidylether of bisphenol A with various diamines

To prepare a high‐performance epoxy, we synthesized three types of diamines {N,N′‐(4,4′‐diphenylether)‐bis(4‐aminophthalimide), 4,4′‐bis(p‐aminophenoxy)dibenzalphentaerythriol, and 2,2′‐bis[4‐(p‐aminobenzoyl)phenyl]propane} as epoxy curing agents with a two‐step reaction sequence. The structures of the synthesized diamines were confirmed with Fourier transform infrared and nuclear magnetic resonance spectroscopy. The curing kinetics and thermal stability of the cured epoxy resin with diglycidylether of bisphenol A were estimated with differential scanning calorimetry and thermogravimetric analysis under a nitrogen atmosphere. The kinetics parameters were determined with the Ozawa and Kissinger equations. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 279–284, 2001     

In situ crosslinkable sulfonated polyaromatic ionomers for the polyelectrolyte used in proton exchange membrane fuel cell

Two series of sulfonated poly(arylene ether nitrile ketone) ionomers containing potential crosslinkable nitrile groups were synthesized in high yield by direct aromatic nucleophilic polycondensation of 1,4‐bis‐(4‐hydroxyphenyl)‐2,3‐dicyano ‐naphthalene ( 3 ) with different molar ratio of disodium 5,5′‐carbonyl‐bis‐(2‐fluorobenzene‐sulfonate) ( 4 ) to 5,5′‐carbonyl‐bis‐(2‐fluorobenzene) ( 5 ) or 4,4‐biphenol ( 7 ). Subsequently, the sulfonated polymeric ionomers were in situ crosslinked when cast into membranes from solution at 180°C under nitrogen protection. The structure of the synthesized polymers was characterized by ¹H‐nuclear magnetic resonance (NMR), Fourier‐transform infrared spectra, and elemental analysis. Comparing with the original polymeric membranes, the crosslinked membranes showed much better thermal and hydrolytic stabilities and superior mechanical properties as well as much lower swelling behavior, which were even better than Nafion 117 membrane. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Recent Developments in Enantioselective Metal‐Catalyzed Domino Reactions

Since the first definition of domino reactions by Tietze in 1993, an explosive number of these fascinating reactions has been developed, allowing the easily building of complex chiral molecular architectures from simple materials to be achieved in a single step. Even more interesting, the possibility to join two or more reactions in one asymmetric domino process catalyzed by chiral metal catalysts has rapidly become one challenging goal for chemists, due to economical advantages, such as avoiding costly protecting groups and time‐consuming purification procedures after each step. The explosive development of enantioselective metal‐catalyzed domino including multicomponent reactions is a consequence of the considerable impact of the advent of asymmetric transition metal catalysis. This review aims to update the last developments of enantioselective one‐, two‐ and multicomponent domino reactions mediated by chiral metal catalysts, covering the literature since the beginning of 2006. Abbreviations: Ac: acetyl; AQN: anthraquinone; Ar: aryl; bdpp: 2,4‐bis(diphenylphosphino)pentane; BINAP: 2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl; BINEPINE: phenylbinaphthophosphepine; BINIM: binapthyldiimine; BINOL: 1,1′‐bi‐2‐naphthol; BIPHEP: 2,2′‐bis(diphenylphosphino)‐1,1′‐biphenyl; Bn: benzyl; Boc: tert‐butoxycarbonyl; Box: bisoxazoline; BOXAX: 2,2′‐bis(oxazolyl)‐1,1′‐binaphthyl; BPTV: N‐benzene‐fused phthaloyl‐valine; Bu: butyl; Bz: benzoyl; Cat: catechol; Chiraphos: 2,3‐bis(diphenylphosphine)butane; cod: cyclooctadiene; Cy: cyclohexyl; DABCO: 1,4‐diazabicyclo[2.2.2]octane; dba: (E,E)‐dibenzylideneacetone; DBU: 1,8‐diazabicyclo[5.4.0]undec‐7‐ene; DCE: dichloroethane; de: diastereomeric excess; DHQ: hydroquinine; DHQD: dihydroquinidine; DIFLUORPHOS: 5,5′‐bis(diphenylphosphino)‐2,2,2′,2′‐tetrafluoro‐4,4′‐bi‐1,3‐benzodioxole; DIPEA: diisopropylethylamine; DMF: dimethylformamide; DMSO: dimethyl sulfoxide; DOSP: N‐p‐dodecylbenzenesulfonylprolinate; DPEN: 1,2‐diphenylethylenediamine; dtb: di‐tert‐butyl; dtbm: di‐tert‐butylmethoxy; E: electrophile; ee: enantiomeric excess; Et: ethyl; FBIP: ferrocene bis‐imidazoline bis‐palladacycle; Fc: ferrocenyl; FOXAP: ferrocenyloxazolinylphosphine; Hex: hexyl; HFIP: hexafluoroisopropyl alcohol; HMPA: hexamethylphosphoramide; iPr‐DuPhos: 1,2‐bis(2,5‐diisopropylphospholano)benzene; Josiphos: 1‐[2‐(diphenylphosphino)ferrocenyl]ethyldicyclohexylphosphine ethanol adduct; L: ligand; MCPBA: 3‐chloroperoxybenzoic acid; Me: methyl; Me‐DuPhos: 1,2‐bis(2,5‐dimethylphospholano)benzene; MEDAM: bis(dimethylanisyl)methyl; MOM: methoxymethyl; Naph: naphthyl; NMI: N‐methylimidazole; MWI: microwave irradiation; Norphos: 2,3‐bis(diphenylphosphino)‐bicyclo[2.2.1]hept‐5‐ene; Ns: nosyl (4‐nitrobenzene sulfonyl); Nu: nucleophile; Oct: octyl; Pent: pentyl; Ph: phenyl; PHAL: 1,4‐phthalazinediyl; Pin: pinacolato; PINAP: 4‐[2‐(diphenylphosphino)‐1‐naphthalenyl]‐N‐[1‐phenylethyl]‐1‐phthalazinamine; Pr: propyl; Py: pyridyl; PYBOX: 2,6‐bis(2‐oxazolyl)pyridine; QUINAP: 1‐(2‐diphenylphosphino‐1‐naphthyl)isoquinoline; QUOX: quinoline‐oxazoline; Segphos: 5,5′‐bis(diphenylphosphino)‐4,4′‐bi‐1,3‐benzodioxole; Solphos: 7,7′‐bis(diphenylphosphino)‐3,3′,4,4′‐tetrahydro‐4,4′‐dimethyl‐8,8′‐bis‐2H‐1,4‐benzoxazine; SPRIX: spirobis(isoxazoline); SYNPHOS: 6,6′‐bis(diphenylphosphino)‐2,2′,3,3′‐tetrahydro‐5,5′‐bi‐1,4‐benzodioxin; Taniaphos: [2‐diphenylphosphinoferrocenyl](N,N‐dimethylamino)(2‐diphenylphosphinophenyl)methane; TBS: tert‐butyldimethylsilyl; TC: thiophene carboxylate; TCPTTL: N‐tetrachlorophthaloyl‐tert‐leucinate; TEA: triethylamine; Tf: trifluoromethanesulfonyl; TFA: trifluoroacetic acid; THF: tetrahydrofuran; TMS: trimethylsilyl; Tol: tolyl; Ts: 4‐toluenesulfonyl (tosyl); C₃‐Tunephos: 1,13‐bis(diphenylphosphino)‐7,8‐dihydro‐6H‐dibenzo[f,h][1,5]dioxonin; VAPOL: 2,2′‐diphenyl‐[3,3′‐biphenanthrene]‐4,4′‐diol     

Morphology,thermal properties,hydrophobicity and O2/N2 gas separation performance of 4,4′‐oxydiphthalic anhydride‐based polyimide/titania hybrids

Two 4,4′‐oxydiphthalic anhydride (ODPA)‐based polyimide (PI)/titania hybrid films with different morphologies were prepared through an in situ sol‐gel process. The precursor, poly(amic acid) (PAA), was synthesized using ODPA, diamine of 2,2‐bis[4‐(4‐aminophenoxy)phenyl]propane (BAPP) or 4,4′‐diaminodiphenyl ether (ODA) and a suitable amount of dimethylformamide solvent. A mixture of tetraethylorthotitanate (Ti(OEt)₄) and acetylacetone with molar ratio of 1:4 was then added to the PAA solution and mixed thoroughly. Following curing, PI/titania hybrid membranes with different crosslinkages and Ti(OEt)₄ contents were prepared. PI hybrids with the longer BAPP diamine present different morphologies and property changes related to the Ti(OEt)₄ content from those of hybrids with the shorter ODA diamine. The morphologies of the two ODPA‐based PI/titania hybrids were studied with reference to the disruption of imide ring formation. Different crosslinked structures produced were identified using Fourier transform infrared analysis from the frequency shift of the C?O band and relative absorbance intensities of bands of C?O group and imide ring (? N?). Thermal properties, O₂/N₂ gas separation performance, contact angle, storage modulus, glass transition temperature and decomposition temperature of the PI hybrids were all found to be functions of the Ti(OEt)₄ content, crosslinked structure and PI type. Copyright © 2012 Society of Chemical Industry     

Synthesis and Characterisation of Polyamides and Polyimides from Amino/Methylene bis[Benzenamine] Styryl Pyridines

Polyamides and polyimides containing diamines, with potential non-linear optical characteristics, were prepared using (E)-4,4′-[[[2-(4-pyridinyl)ethenyl]phenyl]amino]bis[benzenamine] and (E)-4-4′-[[[2-(4-pyridinyl)ethenyl]2-methyl phenyl]amino]bis[benzenamine] condensed with pyromellitic dianhydride to obtain poly(amic acid)s. The poly(amic acid)s were soluble in polar aprotic solvents, such as dimethylformamide, dimethylsulphoxide and dimethylacetamide, and could be cast into transparent, tough, flexible films. Amorphous thermally stable polyimides were formed by cyclodehydration. Similarly, (E)-4,4′-[[[2-(4-pyridinyl)ethenyl]phenyl]methylene]bis[benzenamine] and (E)-4,4′-[[[2-(4-pyridinyl)ethenyl]phenyl]methylene]bis[N-ethylbenzenamine] were condensed with 3-methyladipoyl chloride to obtain other new polyamides. Characterisation using infra-red and nuclear magnetic resonance spectroscopy, X-ray diffraction and thermogravimetric analysis are reported. © 1997 SCI.     

Iron‐Catalyzed Oxidative Mono‐ and Bis‐Phosphonation of N,N‐Dialkylanilines

The dehydrogenative α‐phosphonation of substituted N,N‐dialkylanilines by dialkyl H‐phosphonates was achieved under mild conditions by using environmentally benign iron(II) chloride as catalyst and tert‐butyl hydroperoxide as oxidant. The reaction proceeded in the presence of electron‐donating (methoxy, methyl, benzyl) and electron‐withdrawing ring‐substitutents (bromo, carbonyl, carboxyl, m‐nitro) in moderate to good yields. The X‐ray crystal structure of N‐(5,5‐dimethyl‐2‐oxo‐2λ⁵‐[1,3,2]dioxaphosphinan‐2‐yl‐methyl)‐N‐methyl‐p‐toluidine was determined. Bis‐(4‐(dimethylamino)phenyl)methane and bis‐4,4′‐(dimethylamino)benzophenone underwent bisphosphonation selectively by respective monophosphonation at the remote dimethylamino groups. Furthermore, the use of excess dialkyl H‐phosphonate and oxidant allowed us to functionalize both methyl groups of N(CH₃)₂ in N,N‐dimethyl‐p‐toluidine and N,N‐dimethylaminomesidine, respectively, to obtain α,α′‐bisphosphonatoamines in high yield.     

Preparation of biphenyl‐bridged,crosslinked polyalkoxysilanes: Determination of oil/organic solvent absorption features

A novel type of biphenyl‐bridged alkoxysilane‐based crosslinked polyalkoxysilane was prepared by the condensation of 4,4′‐bis(triethoxysilyl)?1,1′‐biphenyl and different lengths of linear aliphatic diols. Fourier transform infrared spectroscopy, solid‐state ¹³C and ²⁹Si cross‐polarization magic angle spinning nuclear magnetic resonance, and thermogravimetric analysis were used to characterize the biphenyl‐bridged, crosslinked polyalkoxysilanes. The crosslinked polymers were found to have very quick and high swelling capabilities in organic solvents and oils. The absorption–desorption kinetics and reusability features of the crosslinked polymers were also studied, and we found that the synthesized polymers reached their maximum absorption capacity during a variety of tests without losing capacity. We also tested the absorption performance of the sorbents from water surfaces. All of these results confirm that biphenyl‐bridged, crosslinked polyalkoxysilanes could be good candidates as sorbent materials for the cleaning of water from organic contaminants. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44193.     

Synthesis of a novel hexaarylbiimidazole with ether groups and characterization of its photoinitiation properties for acrylate derivatives

A novel photoinitiator 2,2′‐bis‐(2‐chlorophenyl)‐4,4′,5,5′‐tetra‐[3‐(2‐hydroxylmethyl‐2‐triethylene glycol monoethylene ether‐ethane‐1‐oxy)‐phenyl]‐1,2′‐biimidazole (BCTE‐HABI) was synthesized from 3,3′‐dimethoxy benzoin. Ultraviolet spectra, fluorescence spectra, ESR, photodilatometer, and photo‐DSC measurements indicate that its photoinitiating activity for acrylate derivatives is better than 2,2′‐bis‐(2‐chlorophenyl)‐4,4′,5,5′‐tetraphenyl‐1,2′‐biimidazole (o‐Cl‐HABI), which is one of the most widely studied and used derivatives of HABI. POLYM. ENG. SCI., 46:474–479, 2006. © 2006 Society of Plastics Engineers.     

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 polyamides containing sulfone‐ether linkages and xanthene cardo groups

In order to obtain polyamides with enhanced solubility and processability, as well as good mechanical and thermal properties, several novel polyamides containing sulfone‐ether linkages and xanthene cardo groups based on a new diamine monomer, 9,9‐bis[4‐(4‐aminophenoxy)phenyl]xanthene (BAPX), were investigated. The BAPX monomer was synthesized via a two‐step process consisting of an aromatic nucleophilic substitution reaction of readily available 4‐chloronitrobenzene with 9,9‐bis(4‐hydroxyphenyl)xanthene in the presence of potassium carbonate in N,N‐dimethylformamide, followed by catalytic reduction with hydrazine and Pd/C. Four novel aromatic polyamides containing sulfone‐ether linkages and xanthene cardo groups with inherent viscosities between 0.98 and 1.22 dL g^?1 were prepared by low‐temperature polycondensation of BAPX with 4,4′‐sulfonyldibenzoyl chloride, 4,4′‐[sulfonyl‐bis(4‐phenyleneoxy)]dibenzoyl chloride, 3,3′‐[sulfonyl‐bis(4‐phenyleneoxy)]dibenzoyl chloride and 4,4′‐[sulfonyl‐bis(2,6‐dimethyl‐1,4‐phenyleneoxy)]dibenzoyl chloride in N,N‐dimethylacetamide (DMAc) solution containing pyridine. All these new polyamides were amorphous and readily soluble in various polar solvents such as DMAc and N‐methylpyrrolidone. These polymers showed relatively high glass transition temperatures in the range 238–298 °C, almost no weight loss up to 450 °C in air or nitrogen atmosphere, decomposition temperatures at 10% weight loss ranging from 472 to 523 °C and 465 to 512 °C in nitrogen and air, respectively, and char yields at 800 °C in nitrogen higher than 50 wt%. Transparent, flexible and tough films of these polymers cast from DMAc solution exhibited tensile strengths ranging from 78 to 87 MPa, elongations at break from 9 to 13% and initial moduli from 1.7 to 2.2 GPa. Primary characterization of these novel polyamides shows that they might serve as new candidates for processable high‐performance polymeric materials. Copyright © 2010 Society of Chemical Industry     

Synthesis and characterization of novel polyaspartimides derived from 2,2′‐dimethyl‐4,4′‐bis(4‐maleimidophenoxy)biphenyl and various diamines

A novel bismaleimide, 2,2′‐dimethyl‐4,4′‐bis(4‐maleimidophenoxy)biphenyl, containing noncoplanar 2,2′‐dimethylbiphenylene and flexible ether units in the polymer backbone was synthesized from 2,2′‐dimethyl‐4,4′‐bis(4‐aminophenoxy)biphenyl with maleic anhydride. The bismaleimide was reacted with 11 diamines using m‐cresol as a solvent and glacial acetic acid as a catalyst to produce novel polyaspartimides. Polymers were identified by elemental analysis and infrared spectroscopy, and characterized by solubility test, X‐ray diffraction, and thermal analysis (differential scanning calorimetry and thermogravimetric analysis). The inherent viscosities of the polymers varied from 0.22 to 0.48 dL g⁻¹ in concentration of 1.0 g dL⁻¹ of N,N‐dimethylformamide. All polymers are soluble in N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethylsulfoxide, pyridine, m‐cresol, and tetrahydrofuran. The polymers, except PASI‐4, had moderate glass transition temperature in the range of 188°–226°C and good thermo‐oxidative stability, losing 10% mass in the range of 375°–426°C in air and 357°–415°C in nitrogen. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 279–286, 1999     

Highly fluorinated poly(ether‐imide)s derived from 2,2′‐bis(3,4,5‐trifluorophenyl)‐4,4′‐diaminodiphenyl ether and aromatic dianhydrides

A new diamine, 2,2′‐bis(3,4,5‐trifluorophenyl)‐4,4′‐diaminodiphenyl ether (FPAPE) was synthesized through the Suzuki coupling reaction of 2,2′‐diiodo‐4,4′‐dinitrodiphenyl ether with 3,4,5‐trifluorophenylboronic acid to produce 2,2′‐bis(3,4,5‐trifluorophenyl)‐4,4′‐dinitrodiphenyl ether (FPNPE), followed by palladium‐catalyzed hydrazine reduction of FPNPE. FPAPE was then utilized to prepare a novel class of highly fluorinated all‐aromatic poly(ether‐imide)s. The chemical structure of the resulting polymers is well confirmed by infrared and nuclear magnetic resonance spectroscopic methods. Limiting viscosity numbers of the polymer solutions at 25 °C were measured through the extrapolation of the concentrations used to zero. M_n and M_w of these polymers were about 10 000 and 25 000 g mol^?1, respectively. The polymers showed a good film‐forming ability, and some characteristics of their thin films including color and flexibility were investigated qualitatively. An excellent solubility in polar organic solvents was observed. X‐ray diffraction measurements showed that the fluoro‐containing polymers have a nearly amorphous nature. The resulting polymers had T_g values higher than 340 °C and were thermally stable, with 10% weight loss temperatures being recorded above 550 °C. Based on the results obtained, FPAPE can be considered as a promising design to prepare the related high performance polymeric materials. Copyright © 2011 Society of Chemical Industry     

Synthesis and characterization of a novel oligosiloxane containing alternative ladderlike structure via charge‐transfer interaction

A novel oligosiloxane containing alternative ladderlike structure involving viologen groups has been prepared via donor–acceptor interaction‐assisted template polymerization. The monomer used as the electron‐donor component, N,N ′‐bis(3‐methyldimethoxyl‐silylpropyl)‐4,4′‐bipyridinium dihexafluorophosphate and its precursor, N,N ′‐bis(3‐methyldimethoxyl‐silylpropyl)‐4,4′‐bipyridinium dibromide were first synthesized successfully in high yield. This oligosiloxane, which displays interesting electrochromic properties, has been characterized by FTIR, UV–vis, ¹H NMR, ²⁹Si NMR, X‐ray diffraction (XRD), and vapour pressure osmometry (VPO). © 2001 Society of Chemical Industry