Synthesis and fluorescence properties of novel 1,10‐phenanthroline‐functionalized polyaryletherketone and its rare earth complexes

1,10‐Phenanthroline‐functionalized polyaryletherketone (PPEK) was synthesized by the amidation reaction of 5‐amino‐1,10‐phenanthroline with polyaryletherketone containing pendant acyl chloride groups. Subsequently, a series of novel rare earth coordination polymers (with rare earths Eu³⁺, Tb³⁺, Sm³⁺ and Dy³⁺) were prepared, using PPEK as macromolecular ligand and the small 1,10‐phenanthroline (Phen) molecule as synergistic ligand. Their structures were characterized using Fourier transform infrared spectroscopy, elemental analysis and X‐ray diffraction, which confirmed that both PPEK and Phen participated in the coordination reaction with the rare earth ions, and that the rare earth ions could disperse homogeneously in the polymer matrix. The rare earth coordination polymers were soluble in polar solvents such as N,N‐dimethylformamide, N,N‐dimethylacetamide and N‐methylpyrrolidone, and could be easily cast into transparent tough thin films. Fluorescence measurements indicated that all the coordination polymers exhibited the intense characteristic fluorescence of the corresponding rare earth ions under ultraviolet excitation, showing their application potential in optical display devices. Copyright © 2010 Society of Chemical Industry     

Electronegativity Governs Enantioselectivity: Alkyl‐Aryl Cross‐Coupling with Fenchol‐Based Palladium‐Phosphorus Halide Catalysts

A series of bulky, modular, monodentate, fenchol‐based phosphites has been employed in an intramolecular palladium‐catalyzed alkyl‐aryl cross‐coupling reaction. This enantioselective α‐arylation of N‐(2‐bromophenyl)‐N‐methyl‐2‐phenylpropanamide is accomplished with [Pd(C₃H₅)(BIFOP‐X)(Cl)] as precatalysts, which are based on biphenyl‐2,2′‐bisfenchol phosphites (BIFOP‐X, X=F, Cl, Br, etc.). The phosphorus fluoride BIFOP‐F gives the highest enantioselectivity and good yields (64% ee, 88%). Lower selectivities and yields are found for BIFOP halides with heavier halogens (Cl: 74%, 47% ee, Br: 63%, 20% ee). NMR studies on catalyst complexes reveal two equilibrating diastereomeric complexes in equal proportions. In all cases, the phosphorus‐halogen moiety remains intact, pointing to its remarkable stability, even in the presence of nucleophiles. The increasing enantioselectivity of the catalysts with the phosphorus halide ligands correlates with the rising electronegativity of the halide (bromine<chlorine<fluorine), as can be rationalized from structural parameters and DFT computations.     

Synthesis of poly[(2‐oxo‐1,3‐dioxolan‐4‐yl)methyl vinyl ether‐co‐N‐phenylmaleimide] and its miscibility in blends with styrene‐acrylonitrile or poly(vinyl chloride)

The aim of the study was to investigate the synthesis of a copolymer bearing cyclic carbonate and its miscibility with styrene/acrylonitrile copolymer (SAN) or poly(vinyl chloride) (PVC). (2‐Oxo‐1,3‐dioxolan‐4‐yl)methyl vinyl ether (OVE) as a monomer was synthesized from glycidyl vinyl ether and CO₂ using quaternary ammonium chloride salts as catalysts. The highest reaction rate was observed when tetraoctylammonium chloride (TOAC) was used as a catalyst. Even at the atmospheric pressure of CO₂, the yield of OVE using TOAC was above 80% after 6 h of reaction at 80°C. The copolymer of OVE and N‐phenylmaleimide (NPM) was prepared by radical copolymerization and was characterized by FTIR and ¹H‐NMR spectroscopies and differential scanning calorimetry (DSC). The monomer reactivity ratios were given as r₁ (OVE) = 0.53–0.57 and r₂ (NPM) = 2.23–2.24 in the copolymerization of OVE and NPM. The films of poly(OVE‐co‐NPM)/SAN and poly(OVE‐co‐NPM)/PVC blends were cast from N‐dimethylformamide. An optical clarity test and DSC analysis showed that poly(OVE‐co‐NPM)/SAN and poly(OVE‐co‐NPM)/PVC blends were both miscible over the whole composition range. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1809–1815, 2000     

Iridium‐Catalyzed Transfer Hydrogenation of 1,10‐Phenanthrolines using Formic Acid as the Hydrogen Source

The iridium‐catalyzed highly regioselective transfer hydrogenation of a variety of 2‐substituted and 2,9‐disubstituted 1,10‐phenanthrolines under mild conditions with formic acid as the hydrogen source is described. In the presence of a catalytic amount of the iridium complex [Cp*IrCl₂]₂, the transfer hydrogenation proceeded smoothly in 1,4‐dioxane under ligand‐free conditions, exclusively leading to a range of 1,2,3,4‐tetrahydro‐1,10‐phenanthroline products in high yields. The catalyst generated in situ from [Cp*IrCl₂]₂ and (R,R)‐(CF₃)₂C₆H₃SO₂‐dpen [N‐(2‐amino‐1,2‐diphenylethyl)‐3,5‐bis(trifluoromethyl)benzenesulfonamide] could efficiently catalyze the asymmetric transfer hydrogenation of these 1,10‐phenanthrolines in isopropyl alcohol (i‐PrOH) to afford chiral 1,2,3,4‐tetrahydro‐1,10‐phenanthrolines in high yields with up to >99% ee. The key to the success of the reduction is the choice of solvent and hydrogen source.

     

A Highly Efficient Tandem Reaction of 2‐(gem‐Dibromovinyl)phenols(thiophenols) with Organosilanes to 2‐Arylbenzofurans (thiophenes)

2‐Arylbenzofurans(thiophenes) were prepared through an efficient tandem elimination–intramolecular addition–Hiyama cross‐coupling reaction. In the presence of tetra‐(n‐butyl)ammonium fluoride (TBAF), palladium(II) acetate [Pd(OAc)₂] and triphenylphosphine (PPh₃), the reaction of 2‐(gem‐dibromovinyl)phenols(thiophenols) with phenyl(trialkoxy)silanes proceeded smoothly and generated the corresponding products with good yields in one‐pot. It should be noted that TBAF plays an important role in the tandem reaction.     

Palladium‐Catalyzed Fluoride‐Free Cross‐Coupling of Intramolecularly Activated Alkenylsilanes and Alkenylgermanes: Synthesis of Tamoxifen as a Synthetic Application

We have demonstrated that intramolecular hypercoordination of a carboxylic acid is a powerful activation strategy for the palladium‐catalyzed cross‐coupling reaction of trialkyl(vinyl)silanes and trialkyl(vinyl)germanes under fluoride‐free conditions. Z‐β‐Trialkylsilyl‐ and Z‐β‐trialkylgermylacrylic acids, synthesized stereoselectively by olefination with ynolates, are highly stable and useful reagents for cross‐coupling with a variety of aryl iodides to provide tetrasubstituted olefins possessing different carbon substituents in a stereocontrolled and diversity‐oriented manner. An application to a stereoselective synthesis of (Z)‐tamoxifen is also reported.     

Synthesis of polydimethylsiloxane‐block‐polystyrene‐block‐polydimethylsiloxane via polysiloxane‐based macroinitiator in supercritical CO2

Polydimethylsiloxane‐block‐polystyrene‐block‐polydimethylsiloxane (PDMS‐b‐PS‐b‐PDMS) was synthesized by the radical polymerization of styrene using a polydimethylsiloxane‐based macroazoinitiator (PDMS MAI) in supercritical CO₂. PDMS MAI was synthesized by reacting hydroxy‐terminated PDMS and 4,4′‐azobis(4‐cyanopentanoyl chloride) (ACPC) having a thermodegradable azo‐linkage at room temperature. The polymerization of styrene initiated by PDMS MAI was investigated in a batch system using supercritical CO₂ as the reaction medium. PDMS MAI was found to behave as a polyazoinitiator for radical block copolymerization of styrene, but not as a surfactant. The response surface methodology was used to design the experiments. The parameters used were pressure, temperature, PDMS MAI concentration and reaction time. These parameters were investigated at three levels (?1, 0 and 1). The dependent variable was taken as the polymerization yield of styrene. PDMS MAI and PDMS‐b‐PS‐b‐PDMS copolymers obtained were characterized by proton nuclear magnetic resonance and infrared spectroscopy. The number‐ and weight‐average molecular weights of block copolymers were determined by gel permeation chromatography. Copyright © 2004 Society of Chemical Industry     

RAFT polymerization of N‐vinyl pyrrolidone using prop‐2‐ynyl morpholine‐4‐carbodithioate as a new chain transfer agent

RAFT polymerization of N‐vinyl pyrrolidone (NVP) has been investigated in the presence of chain transfer agent (CTA), i.e., prop‐2‐ynyl morpholine‐4‐carbodithioate (PMDC). The influence of reaction parameters such as monomer concentration [NVP], molar ratio of [CTA]/[AIBN, i.e., 2,2′‐azobis (2‐methylpropionitrile)] and [NVP]/[CTA], and temperature have been studied with regard to time and conversion limit. This study evidences the parameters leading to an excellent control of molecular weight and molar mass dispersity. NVP has been polymerized by maintaining molar ratio [NVP]: [PMDC]: [AIBN] = 100 : 1 : 0.2. Kinetics of the reaction was strongly influenced by both temperature and [CTA]/[AIBN] ratio and to a lesser extent by monomer concentration. The activation energy (E_a = 31.02 kJ mol^?1) and enthalpy of activation (ΔH^?= 28.29 kJ mol^?1) was in a good agreement to each other. The negative entropy of activation (ΔS^? = ?210.16 J mol^‐1K^‐1) shows that the movement of reactants are highly restricted at transition state during polymerization. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Palladium‐Catalyzed Efficient and One‐Pot Synthesis of Diarylacetylenes from the Reaction of Aryl Chlorides with 2‐Methyl‐3‐butyn‐2‐ol

An efficient and practical synthetic method has been developed for the preparation of symmetrical diarylacetylenes from the direct reaction of aryl chlorides with 2‐methyl‐3‐butyn‐2‐ol catalyzed by palladium(II) chloride‐bis(tricyclohexylphosphine) [PdCl₂(PCy₃)₂] under mild reaction conditions. Unsymmetrical diarylated acetylenes could be also obtained by using two different aryl chlorides simultaneously. The catalytic procedure includes a novel one‐pot palladium‐catalyzed, double Sonogashira coupling of inactivated aryl chlorides without use of copper(I) as co‐catalyst.     

Scope and Limitations of Palladium‐Catalyzed Cross‐Coupling Reactions with Organogold Compounds

Five different alkenylgold(I) phosphane complexes were prepared and then investigated in [1,1′‐bis(diphenylphosphino)ferrocene]palladium(II) dichloride‐catalyzed cross‐coupling reactions with different aryl halides, heterocyclic halides, an alkenyl halide, an alkynyl halide, allylic substrates, benzyl bromide and an acid chloride. With regard to the halides, the iodides were highly reactive, bromides or chlorides gave significantly reduced yields or failed, allylic acetates failed, too. The cross‐coupling partners contained a number of different functional groups, while free carboxylic acids did not deliver cross‐coupling products and o,o‐disubstituted arenes failed as well, a broad range of other functional groups like nitro groups, nitrile groups, ester groups, α,β‐unsaturated ester groups and lactones, aldehydes, alkoxy groups, pyridyl groups, thienyl groups, unprotected phenols and anilines, even aryl azides were tolerated. The structures of one alkenylgold(I) species and of four of the cross‐coupling products were proved by crystal structure analyses.     

Preparation and properties of Fe(II)‐ion‐sensitive colour‐changing fabric

Textile fabrics were dyed with complexometric indicators (ionochromic dyes) to develop Fe(II) ionochromic fabric. Three kinds of ionochromic dye were used to dye silk fabric, and they were evaluated for colour changes triggered by Fe(II) solution. The K/S values and photos of the fabrics were then recorded. It was found that 1,10‐phenanthroline was the most suitable ionochromic dye in these dyes. Colour change from white to red could be clearly seen when 1,10‐phenanthroline‐dyed silk fabric was triggered by Fe(II) solution, but it showed no colour change when triggered by Cu(II), Mg(II), or Ca(II) solution. Moreover, 1,10‐phenanthroline‐dyed nylon, polyester, and cotton fabrics showed no obvious colour changes after triggering by Fe(II) solution. Ion concentration, pH value, and reaction time could affect the colour changes. When triggered by 8 mg l^?1 of Fe(II) solution at neutral pH for about 15 min, the ionochromic fabric showed a clear colour change. In addition, three coloured fabrics in green, blue, and yellow were also dyed with 1,10‐phenanthroline. It was found that they could also show clear colour changes when triggered by Fe(II) solution. These ionochromic fabrics may find broad application in many fields, such as Fe(II) detection, magic toys, anticounterfeiting materials, and bionic silk flowers.     

Synthesis and reactive features of a terpolymer: Poly(N‐vinyl‐2‐pyrrolidone‐co‐vinyl acetate‐co‐glycidyl methacrylate)

A polyvinyl pyrrolidone terpolymer system is described that can be chemically cross‐linked at moderate, 70–100°C, temperatures. The system has significant potential for development of durable long‐lasting pyrrolidone coatings in a wide range of applications, particularly in water filtration membrane construction where leaching is an unresolved, serious problem. The synthesis of the terpolymer, poly(N‐vinyl‐2‐pyrrolidone‐co‐vinyl acetate‐co‐glycidyl methacrylate), by free radical polymerization is described. The reactive features of this terpolymer are presented in the context of acidic anhydride curing. In a polar aprotic solvent, the terpolymer is reacted with poly(methyl vinyl ether‐co‐maleic acid) and cured thermally. Key aspects of the terpolymer synthesis and the acid anhydride cross‐linking reaction using DSC, rheology, FTIR, and a small molecule model system to study the cross‐linking chemistry are presented. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Organocatalytic Radical Involved Oxidative Cross‐Coupling of N‐Hydroxyphthalimide with Benzylic and Allylic Hydrocarbons

The cross‐coupling reaction between N‐hydroxyphthalimide and various benzylic and allylic hydrocarbons was realized through an organocatalytic radical‐mediated process involving C(sp³) O bond formation using tert‐butyl hydroperoxide (t‐BuOOH) as an oxidant and tetra‐n‐butylammonium iodide [(n‐Bu]₄NI] as a catalyst, during which the phthalimide N‐oxyl (PINO) radical and benzylic and allylic radicals were generated in situ and underwent the selective radical/radical cross‐coupling reaction. This novel method provides a convenient metal‐free approach to the synthesis of O‐alkylated hydroxy imides under mild reaction conditions.

     

Nonionic water‐soluble polymer: Preparation,characterization, and application of poly(1‐vinyl‐2‐pyrrolidone‐co‐hydroxyethylmethacrylate) as a polychelatogen

The free‐radical copolymerization of water‐soluble poly(1‐vinyl‐2‐pyrrolidone‐co‐hydroxyethylmethacrylate) was carried out with a feed monomer ratio of 75:25 mol %, and the total monomer concentration was 2.67M. The synthesis of the copolymer was carried out in dioxane at 70°C with benzoyl peroxide as the initiator. The copolymer composition was obtained with elemental analysis and ¹H‐NMR spectroscopy. The water‐soluble polymer was characterized with elemental analysis, Fourier transform infrared, ¹H‐ and ¹³C‐NMR spectroscopy, and thermal analysis. Additionally, viscosimetric measurements of the copolymer were performed. The thermal behavior of the copolymer and its complexes were investigated with differential scanning calorimetry (DSC) and thermogravimetry techniques under a nitrogen atmosphere. The copolymer showed high thermal stability and a glass transition in the DSC curves. The separation of various metal ions by the water‐soluble poly(1‐vinyl‐2‐pyrrolidone‐co‐hydroxyethylmethacrylate) reagent in the aqueous phase with liquid‐phase polymer‐based retention was investigated. The method was based on the retention of inorganic ions by this polymer in a membrane filtration cell and subsequent separation of low‐molar‐mass species from the polymer/metal‐ion complex formed. Poly(1‐vinyl‐2‐pyrrolidone‐co‐hydroxyethylmethacrylate) could bind metal ions such as Cr(III), Co(II), Zn(II), Ni(II), Cu(II), Cd(II), and Fe(III) in aqueous solutions at pHs 3, 5, and 7. The retention percentage for all the metal ions in the polymer was increased at pH 7, at which the maximum retention capacity could be observed. The interaction of inorganic ions with the hydrophilic polymer was determined as a function of the pH and filtration factor. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 178–185, 2006     

UV‐Triggered Optical Response and Oxygen Scavenging Ability of a Water‐Soluble Poly(N,N‐dimethylacrylamide‐co‐2‐vinylbenzylanthraquinone) Copolymer

A vinyl‐modified anthraquinone (AQ) derivative (Vinyl‐AQ) is synthesized through a palladium‐mediated Suzuki coupling reaction between vinylphenylboronic acid and 2‐chloromethylanthraquinone and, subsequently, copolymerized with N,N‐dimethylacrylamide (DMAM) through free radical copolymerization in organic solvent. The chemical structure of the resulting water‐soluble copolymer, P(DMAM‐co‐AQ), is verified using techniques such as proton nuclear magnetic resonance, attenuated total reflection‐infrared spectroscopy, thermogravimetric analysis, and UV–vis spectroscopy. The evolution of the oxygen scavenging abilities of aqueous P(DMAM‐co‐AQ) solutions after UV irradiation is monitored as a function of UV irradiation time, concentration of AQ moieties, and pH. The copolymer is proved an effective UV‐triggered oxygen scavenger, leading to dissolved oxygen contents below 1 ppm for the optimized experimental conditions. This behavior is related with the appearance of novel chemical species with interesting optical properties, as suggested by the respective evolution of the UV–vis absorption and photoluminescence spectra after UV irradiation.     

Aerobic Oxidation of Benzylic Alcohols in Water by 2,2,6,6‐Tetramethylpiperidine‐1‐oxyl (TEMPO)/Copper(II) 2‐N‐Arylpyrrolecarbaldimino Complexes

Novel copper(II) 2‐N‐arylpyrrolecarbaldimine‐based catalysts for the aerobic oxidation of benzylic alcohols mediated by the 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) radical are reported. The catalytic activity for both synthesized and in situ made complexes in alkaline water solutions was studied revealing high efficiency and selectivity (according to GC selectivity always >99%) for both of these catalytic systems. For example, quantitative conversion of benzyl alcohol to benzaldehyde can be achieved with the in situ prepared bis[2‐N‐(4‐fluorophenyl)‐pyrrolylcarbaldimide]copper(II) catalysts in 2 h with atmospheric pressure of O₂ at 80 °C. Interestingly, these catalysts can utilize dioxygen as well as air or hydrogen peroxide as the end oxidants, producing water as the only by‐product.     

Photoluminescence emission of a stable and well‐dispersed unsaturated polyester‐co‐rare‐earth complex

A series of unsaturated polyester (UPR)‐co‐rare‐earth complex (REX) photoluminescence materials with red and green luminescence were fabricated. REXs with double bonds, including complex of europium (Eu³⁺) (methacrylic acid)₃ and 1,10‐phenanthroline (Phen) [Eu(MAA)₃Phen], and complex of terbium (Tb³⁺)(methacrylic acid)₃ and Phen [Tb(MAA)₃Phen], and UPR acted as functional monomers and the polymer matrix, respectively. Fourier transform infrared and UV absorption spectroscopy confirmed the chemical structure of the resulting UPR‐co‐REX according to the free‐radical polymerization mechanism. The study of fluorescence distribution by means of laser scanning confocal microscopy indicated that the REX materials were uniformly dispersed in the UPR matrix. The effects of the type and dosage of REX on the fluorescence intensity and stability were examined via fluorescence spectrometry. We found that the optical/physical properties of the REX were improved by UPR molecular skeleton structures. The fluorescence intensity increased with increasing use of the REX and reached a maximum value when the REX content was 12 wt %. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45253.     

Sulfonated N‐Heterocyclic Carbenes for Pd‐Catalyzed Sonogashira and Suzuki–Miyaura Coupling in Aqueous Solvents

The reactions of the N,N′‐diarylimidazolium and N,N′‐diarylimidazolinium salts with chlorosulfonic acid result in the formation of the respective disulfonated N‐heterocyclic carbene (NHC) precursors in reasonable yields (46–77%). Water‐soluble palladium catalyst complexes, in situ obtained from the respective sulfonated imidazolinium salt, sodium tetrachloropalladate (Na₂PdCl₄) and potassium hydroxide (KOH) in water, were successfully applied in the copper‐free Sonogashira coupling reaction in isopropyl alcohol/water mixtures using 0.2 mol% catalyst loading. The preformed (disulfonatedNHC)PdCl(cinnamyl) complex was used in aqueous Suzuki–Miyaura reactions at 0.1 mol% catalyst loading. The coupling protocol reported here is very useful for Sonogashira reactions of N‐ and S‐heterocyclic aryl bromides and chlorides with aryl‐ and alkylacetylenes.     

Highly Efficient Suzuki Coupling Reaction of α‐Chloroalkylidene‐β‐lactones and β‐Lactams with Organoboronic Acids

The activation of C Cl bond of (Z)‐α‐chloroalkylidene‐β‐lactones and (E)‐α‐chloroalkylidene‐β‐lactams via the Suzuki cross‐coupling reaction is reported in this paper. Alkyl, heteroaromatic, substituted phenyl‐ and alkenylboronic acids can be coupled with a wide variety of α‐chloroalkylidene‐β‐lactones and β‐lactams in excellent yields within a short period of time. The cross‐coupling reaction of optically active substrates leads to the optically active compounds without racemization of the corresponding chiral center.     

Synthesis of functionalized polymeric adsorbent selective to cobalt

Amino derivative of chloromethylated polystyrene resin was synthesized and functionalized by 1,10‐phenanthroline (1,10‐Phen) to yield a novel adsorbent, namely 4‐methylamino‐[N,N‐bis(2,2^′)‐1,10‐phenanthroline] polystyrene ( 4‐MABPPS ). The complete development of novel adsorbent along with its characterization is described in detail. The adsorption ability and selectivity of 4‐MABPPS were investigated for cobalt and zirconium ions so as to efficiently separate cobalt ion impurities from zircalloy cladding material of nuclear reactors. The experimental results showed selective uptake of cobalt by the adsorbent in the presence of zirconium. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012