Polymerization and characterization of various di(pyridine)bis(trihalophenolato)cobalt(II) complexes in solid and melt states

The syntheses of distorted tetrahedral bis(pyridine)bis(trihalophenolato)cobalt(II) complexes from an aqueus solution were achieved and their characterization by FT‐IR, X‐ray, DSC, UV‐visible and elemental analysis in solid state or in melt form is reported. Polymerizations of these complexes were accomplished either at constant temperature, employing different time intervals or constant decomposition times while varying the temperature range. The slow decomposition at constant temperature leads to long chain products, whereas long chains formed at higher temperatures were during a constant time. The resulting poly(dihalophenylene oxide)s were characterized by FT‐IR, ¹H NMR, ¹³C NMR spectral analysis, differential scanning calorimetry and molecular weight determinations by viscometric method. © 2001 Society of Chemical Industry     

Synthesis and characterization of a homoleptic titanium dihydrobis(pyrazol-1-yl)borate complex

The neutral titanium(III) complex Ti(BP)₃ {BP = dihydrobis(pyrazol-1-yl)borate} was synthesized by reacting TiCl₃(THF)₂ with an excess of the potassium salt of the ligand in THF. The compound was isolated as a green solid and characterized by elemental analysis, NMR and IR spectroscopy, Mass spectrometry and magnetic and conductivity measurements. The molecular ion was detected in the Mass spectrum. ¹¹B NMR data suggested a distortion from the ideal octahedral geometry caused by the d¹ electronic configuration of the metal centre and this hypothesis was confirmed by means of DFT calculations.     

Electrochemical behavior of europium (III) in N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide

N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPyNTf₂) was synthesized and characterized by CHNS elemental analysis, ¹H and ¹³C NMR and IR spectroscopy. Europium tris[bis(trifluoromethylsulfonyl)imide] (Eu(NTf₂)₃) was prepared and studied for the electrochemical behavior of Eu(III) in BMPyNTf₂ at glassy carbon and stainless steel working electrodes at 298-373 K by cyclic voltammetry, chronopotentiometry and chronoamperometry. Cyclic voltammogram of Eu(III) in BMPyNTf₂ consisted of a quasi-reversible cathodic wave at −0.45 V (vs. Fc/Fc⁺, 373 K), which could be attributed to the reduction of Eu(III) to Eu(II) and an irreversible wave at −2.79 V (vs. Fc/Fc⁺) due to reduction of Eu(II) to Eu(0). The diffusion coefficient of Eu(III) in BMPyNTf₂ was determined to be in the range of ∼10⁻⁷ cm² s⁻¹ by various electrochemical methods and the charge transfer rate constant was determined to be ∼10⁻⁵ cm s⁻¹ by cyclic voltammetry.     

Synthesis,characterization and antibacterial activity of Pd(II), Pt(II) and Ag(I) complexes of 4-ethyl and 4-(p-tolyl)-1-(pyridin-2-yl)thiosemicarbazides

Pd(II), Pt(II) and Ag(I) ions were found to form stable complexes with 4-(p-tolyl)- or 4-ethyl-1-(pyridin-2-yl)thiosemicarbazides (Hp-TPTS or HEPTS). The complex structure was elucidated by analysis (elemental and thermal), spectroscopy (electronic, IR and ¹H NMR spectra) and physical measurements (magnetic susceptibility and molar conductance). The ligands coordinate to the metal ions as monobasic bidentate through nitrogen and sulfur atoms. The electronic spectra of the Pt(II) complexes in DMF showed a metal to ligand charge transfer transition at 11,935–13,260 cm^?1. The structural, electronic and vibrational features of HEPTS and Hp?TPTS were discussed on the basis of semi-empirical quantum mechanic calculations [ZINDO/S and semi-empirical parameterization (PM3)]. The simulated IR and electronic spectra are found reasonable in accordance with the experimental data. Finally, the antibacterial activities of the ligands and their complexes were investigated and some were found promising.     

Synthesis and characterization of poly(urethane‐ester)s based on calcium salt of mono(hydroxybutyl)phthalate

Calcium‐containing poly(urethane‐ester)s (PUEs) were prepared by reacting diisocyanate (HMDI or TDI) with a mixture of calcium salt of mono(hydroxybutyl)phthalate [Ca(HBP)₂] and hydroxyl‐terminated poly(1,4‐butylene glutarate) [HTPBG₁₀₀₀], using di‐n‐butyltin‐dilaurate as catalyst. About six calcium‐containing PUEs having different composition were synthesized by taking the mole ratio of Ca(HBP)₂:HTPBG₁₀₀₀:diisocyanate (HMDI or TDI) as 3:1:4, 2:2:4, and 1:3:4. Two blank PUEs were synthesized by the reaction of HTPBG₁₀₀₀ with diisocyanate (HMDI or TDI). The polymers were characterized by IR, ¹H NMR, Solid state ¹³C‐CP‐MAS NMR, TGA, DSC, XRD, solubility, and viscosity studies. The T_g value of PUEs increases with increase in the calcium content and decreases with increase in soft segment content. The viscosity of the calcium‐containing PUEs increases with increase in the soft segment content and decreases with increase in the calcium content. X‐ray diffraction patterns of the polymers show that the HMDI‐based polymers are partially crystalline and TDI‐based polymers are amorphous in nature. The dynamic mechanical analysis of the calcium‐containing PUEs based on HMDI shows that with increase in the calcium content of polymer, modulus (g′ and g″) increases at any given temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1720–1727, 2006     

Photopolymer: synthesis and characterization of poly(4‐methacryloyloxyphenyl‐4′‐chlorostyryl ketone)

Methacrylate monomer containing a photodimerizable α,β‐unsaturated ketone moiety was prepared and polymerized in ethyl methyl ketone at 70 °C using benzoyl peroxide as an initiator. The polymer was characterized by UV, IR, ¹H NMR and ¹³C NMR spectra. The molecular weights (M _w and M _n) of the polymer were determined by gel permeation chromotography. The thermal stability of the polymer was measured by thermogravimetric analysis in air and nitrogen. The glass transition temperature of the polymer was determined by differential scanning calorimetry. The photo reactivity of the polymer was investigated as thin film and in solution. © 2000 Society of Chemical Industry     

Synthesis and properties of poly(aryl ether sulfone ether ketone ketone) (PESEKK)

4,4′‐bis(Phenoxy)diphenyl sulfone (DPODPS) was synthesized by reaction of phenol with bis(4‐chlorophenyl) sulfone in tetramethylene sulfone in the presence of NaOH. Two poly(aryl ether sulfone ether ketone ketone)s (PESKKs) with high molecular weight were prepared by low temperature solution polycondensation of DPODPS and terephthaloyl chloride (TPC) or isophthaloyl chloride (IPC), respectively, in 1,2‐dichloroethane and in the presence of aluminum chloride (AlCl₃) and N‐methylpyrrolidone (NMP). The resulting polymers were characterized by various analytical techniques, such as FT‐IR, ¹H‐NMR, DSC, TG, and WAXD. The results show that the T_g and T_d of PESEKKs are much higher, but its T_m is lower than those of PEKK. The other results indicate that PESEKKs exhibit excellent thermostabilities at 300 ± 10°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 489–493, 2005     

Synthesis and characterization of hyperbranched poly(silyl ester)s

Hyperbranched poly(silyl ester)s were synthesized via the A₂ + B₄ route by the polycondensation reaction. The solid poly(silyl ester) was obtained by the reaction of di‐tert‐butyl adipate and 1,3‐tetramethyl‐1,3‐bis‐β(methyl‐dicholorosilyl)ethyl disiloxane. The oligomers with tert‐butyl terminal groups were obtained via the A₂ + B₂ route by the reaction of 1,5‐dichloro‐1,1,5,5‐tetramethyl‐3,3‐diphenyl‐trisi1oxane with excess amount of di‐tert‐butyl adipate. The viscous fluid and soft solid poly(silyl ester)s were obtained by the reaction of the oligomers as big monomers with 1,3‐tetramethyl‐1,3‐bis‐β(methyl‐dicholorosilyl)ethyl disiloxane. The polymers were characterized by ¹H NMR, IR, and UV spectroscopies, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The ¹H NMR and IR analysis proved the existence of the branched structures in the polymers. The glass transition temperatures (T_g's) of the viscous fluid and soft solid polymers were below room temperature. The T_g of the solid poly(silyl ester) was not found below room temperature but a temperature for the transition in the liquid crystalline phase was found at 42°C. Thermal decomposition of the soft solid and solid poly(silyl ester)s started at about 130°C and for the others it started at about 200°C. The obtained hyperbranched polymers did not decompose completely at 700°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3430–3436, 2006     

Coordination Polymers of 1,9-Bis(8-Hydroxyquinolin-5-yl)-2,5,8-Trioxanonane

ABSTRACT

Coordination polymers of a novel bis(oxine) bidentate ligand, namely 1,9-bis(8-hydroxyquinolin-5-yl)-2,5,8-trioxanonane (BHQTN) (H₂L) have been prepared with the metal ions Zn⁺², Cu⁺², Ni⁺², Co⁺², and Mn⁺². The novel bis(bidentate) ligand BHQTN was synthesized by condensation of 5-chloromethyl-8-hydroxyquinoline hydrochloride with diethylene glycol in the presence of a base catalyst. All of these coordination polymers and the parent ligand were characterized by elemental analyses and IR spectral studies. The diffuse reflectance spectral studies and magnetic susceptibilities of all of the coordination polymers have also been performed. Thermogravimetric parameters such as T_o, T₁₀, T_max., IPDT, and the activation energy of the thermo-degradation process were calculated.     

(S)-2-(ethyl propionate)-(O-ethyl xanthate)- and (S)-2-(Ethyl isobutyrate)-(O-ethyl xanthate)-mediated RAFT polymerization of vinyl acetate

(S)-2-(Ethyl propionate)-(O-ethyl xanthate) (X1) and (S)-2-(Ethyl isobutyrate)-(O-ethyl xanthate) (X2) were used as the reversible addition-fragmentation chain transfer (RAFT) agents for the radical polymerization of vinyl acetate (VAc). The former showed the better chain transfer ability in the polymerization at 60°C. Kinetic study with both RAFT agents showed pseudo-first order kinetics up to around 85% monomer conversion. Molecular weight of the resulting polymer increased linearly with increase in the monomer conversion up to around 85%. The observed molecular weights calculated from ¹H-NMR spectrum [M_n(NMR)] are close to the corresponding theoretical molecular weights [M_n(theor)]. The corresponding polydispersity index (PDI) of the resulting polymers remained almost constant at around 1.2 up to ∼ 65% monomer conversion and then increased gradually with the further increase in the monomer conversion. Chain-end analysis of the resulting polymers by ¹H-NMR showed clearly that polymerization started with the radical forming out of the xanthate mediator. The negligible homo-chain extension and the hetero-chain extension involving synthesis of poly(VAc)-b-poly(NVP) diblock copolymer were occurred. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis of bis(hydroxyethyl ether)s of aromatic dihydroxy compounds and poly(ether-carbonate)s with bisphenol A

A new class of copoly(ether-carbonate)s was synthesized using a melt polycondensation reaction of the bis(hydroxyethyl ether) of bisphenol A with bisphenols and diphenyl carbonate. Copolymers with a wide range of T_g values (62–140°C) were obtained. The copolymer structures were established by ¹H NMR, ¹³C NMR and FTIR investigations. © 1998 Society of Chemical Industry     

A Novel Insensitive High Explosive 3,4‐Bis (Aminofurazano) Furoxan

A novel insensitive high explosive 3,4‐bis (aminofurazano) furoxan (BAFF) was prepared using 3‐amino‐4‐acylchloroximinofurazan (ACOF) as a precursor. The molecular and crystal structures of BAFF were characterized by IR, MS, ¹H NMR, ¹³C NMR, elemental analysis, and single crystal X‐ray diffraction. The single crystal structure of BAFF recrystallized from water is monoclinic, space group P 21/c, and ρ_c=1.745 g cm⁻³, and that recrystallized from ethanol is triclinic, space group P 1, and ρ_c=1.737 g cm⁻³. BAFF has multiple crystal forms. The calculated detonation velocity by BKW code is 8100 m s⁻¹ (ρ=1.795 g cm⁻³, theoretical density calculated by quantum chemistry) and the experimental value is 7177 m s⁻¹ (ρ=1.530 g cm⁻³, charge density). The tested values of impact, friction, and electrostatic spark sensitivity show that BAFF is insensitive.     

Ionic liquid‐catalyzed aminolysis of poly(ethylene terephthalate) waste

Aminolytic depolymerization of poly(ethylene terephthalate) (PET) bottle waste with ethanolamine and hydrazine hydrate under atmospheric conditions was investigated in the presence of room temperature ionic liquids. 1‐Hexyl‐3‐methylimidazolium trifluoromethanesulfonate (Hmim.TfO) and 1‐butyl‐3‐methylimidazolium hydrogen sulfate (Bmim.HSO₄). (Hmim.TfO) was found to be the most efficient catalyst to obtain high yields of the aminolysis products bis(2‐hydroxy ethylene) terephthalamide and terephthalic dihydrazide using ethanolamine and hydrazine hydrate, respectively. These products were characterized by IR spectroscopy, ¹H NMR, ¹³C NMR, mass spectroscopy, and differential scanning calorimetry. The influence of experimental parameters, such as the amount of catalyst, reaction time, molar ratio of ethanolamine, and hydrazine hydrate with respect to PET was investigated. This protocol proves to be efficient and environmentally benign in terms of high yields (>84%) and low reaction times (up to 30 min). © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis of poly(urethane)s based on diphenyl‐silane/germane and oxyphenyl units: Structure–properties relationship

A series of poly(urethane)s (PUs) based on diphenyl‐silane or ‐germane and oxyphenyl units were synthesized by polycondesation of 4‐[4‐[9‐[4‐(4‐aminophenoxy)‐3‐methyl‐phenyl]fluoren‐9‐yl]‐2‐methyl‐phenoxy]aniline (3) and four bis(chloroformate)s ( I–IV ). These monomers were prepared and characterized in previous works. The best conditions for the polymerization reactions were investigated by a kinetic study. Also, a selection of the best solvent for the reaction was developed. Polymers were characterized by IR and ¹H, ¹³C, and ²⁹Si‐NMR spectroscopy and the results were in agreement with the proposed structures. Poly(urethane)s showed inherent viscosity values between 0.12 and 0.31 dL/g, indicative of low molecular weight species, probably of oligomeric nature. The glass transition temperature (T_g) values were observed in the 127–168°C range by DSC analysis. Thermal decomposition temperature (TDT_10%) values were above 300°C. All PUs showed good transparency in the visible region (>80% at 350 nm) due to the incorporation of the bulky monomer (fluorene) and oxyether linkages. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis,Crystal Structure,and Thermal Behaviors of 3‐Nitro‐1,5‐bis(4,4′‐dimethylazide)‐1,2,3‐triazolyl‐3‐azapentane (NDTAP)

The energetic material, 3‐nitro‐1,5‐bis(4,4′‐dimethyl azide)‐1,2,3‐triazolyl‐3‐azapentane (NDTAP), was firstly synthesized by means of Click Chemistry using 1,5‐diazido‐3‐nitrazapentane as main material. The structure of NDTAP was confirmed by IR, ¹H NMR, and ¹³C NMR spectroscopy; mass spectrometry, and elemental analysis. The crystal structure of NDTAP was determined by X‐ray diffraction. It belongs to monoclinic system, space group C2/c with crystal parameters a=1.7285(8) nm, b=0.6061(3) nm, c=1.6712(8) nm, β=104.846(8)°, V=1.6924(13) nm³, Z=8, μ=0.109 mm⁻¹, F(000)=752, and D_c=1.422 g cm⁻³. The thermal behavior and non‐isothermal decomposition kinetics of NDTAP were studied with DSC and TG‐DTG methods. The self‐accelerating decomposition temperature and critical temperature of thermal explosion are 195.5 and 208.2 °C, respectively. NDTAP presents good thermal stability and is insensitive.     

Structural investigations of (9‐ethyl‐carbazol‐6‐yl) methyl methacrylate/methyl acrylate copolymers using two‐dimensional NMR spectroscopy

(9‐Ethyl‐carbazol‐6‐yl) methyl methacrylate/methyl acrylate (E/A) copolymers of different compositions were prepared by solution polymerization by varying the molar infeed ratio, using AIBN as initiator at 60°C. The reactivity ratios calculated by Kelen–Tudos (KT) method were found to be r_E = 1.16 ± 0.02 and r_A = 0.69 ± 0.01 whereas those calculated from RREVM method were found to be r_E = 1.18 and r_A = 0.68. The molecular weights (M_w) and polydispersity index (PDI, M_w/M_n) were determined using gel permeation chromatography (GPC). Glass transition temperatures (T_g) for different compositions of E/A copolymers were determined using differential scanning calorimetry (DSC). Copolymer molar outfeed ratio (F_E) was calculated from ¹H NMR spectra. The α‐methyl, methine, backbone methylene, and quaternary carbon resonance signals of the copolymers were distinguished using ¹³C{¹H}, DEPT‐45, ‐90, and ‐135 NMR techniques. The α‐methyl and β‐methylene showed compositional and configurational sensitivity up to pentad and tetrad level, respectively, whereas methine showed only compositional sensitivity up to pentad level. Unambiguous assignments for ¹H and ¹³C{¹H} NMR spectra were done by correlating 1D (¹H, ¹³C{¹H}, DEPT) and 2D (HSQC, TOCSY) NMR data. The spectral assignments for carbonyl region were done by studying higher bond order couplings by heteronuclear multibond correlation (HMBC) spectra. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5595–5606, 2006     

Synthesis of poly(vinyl propionate) from poly(vinyl alcohol) in nonaqueous medium using ethyl nitrate dimethyl sulfoxide as a catalyst

Poly(vinyl alcohol) (PVA) can be dissolved in a nonaqueous medium in the presence of catalytic concentration of ethyl nitrate dimethyl sulfoxide, C₂H₅ONO₂·DMSO. From the PVA solution, poly(vinyl propionate), PVPR was prepared by the homogeneous esterification of PVA with propionic acid. The ester thus formed contained some unconverted hydroxyl group. The formation of the ester was confirmed by the IR and ¹H‐NMR spectra. The molecular weight of the ester was determined by GPC and intrinsic viscosity (η) was determined by viscometric method. Glass transition temperature, T_g, was obtained from differential scanning calorimetric (DSC) analysis. Thermal stabilities of the ester were checked by thermogravimetric analysis (TGA) and differential thermogravimetric (DTG) analysis. The efficiency of the ester as a flow improver of crude oil was also examined. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5675–5679, 2006     

Structure and properties of hydrophobic cationic poly(vinyl alcohol)

A new class of derivatives of poly(vinyl alcohol) (PVA) was prepared through hydrophobic cationic modification. The structure and composition of PVA grafted with glycidyl‐N‐alkyl‐N,N‐dimethyl‐ammonium chloride (DA) (PVA‐ graft ‐DA) was confirmed with Fourier transform infrared spectral analysis and ¹H NMR spectral analysis. The stress‐strain curves of PVA‐ graft ‐DA samples all exhibited an elastic deformation stress plateau, and strain hardening behavior can be observed, indicating the transition of PVA from brittle fracture to ductile fracture. Compared with virgin PVA, the relaxation peak (T_g) of PVA‐ graft ‐DA shifted to a lower temperature. With increasing alkyl chain length and grafting ratio of DA, T_g decreased, and PVA‐ graft ‐DA exhibited a gradually decreasing storage modulus over the whole temperature range of testing due to the relatively weak intermolecular hydrogen bonding and increasing flexibility of molecular chains by introduction of long alkyl chains. PVA crystallites were not affected by grafting with DA, while the crystallization temperature and crystallinity of PVA were improved and the grain size decreased. On grafting with DA, the fracture surface of PVA changed from a smooth surface to regularly distanced striations, displaying much obvious character of tough fracture, indicating that appropriate intermolecular association of the hydrophobic groups facilitated the formation of physical entanglement of molecular chains to strengthen and toughen the PVA matrix. PVA‐ graft ‐DA showed a significant decreasing surface tension with polymer concentration, while the surface tension of PVA‐ graft ‐DA12 dropped most dramatically and declined with increasing grafting ratio of DA12, indicating improvement of the surface activity of PVA by introduction of hydrophobic alkyl chains and hydrophilic cationic groups. Copyright © 2011 Society of Chemical Industry     

Synthesis, X-ray structure and Hg, Se CP MAS NMR studies on the first tris(imidazolidine-2-selone) mercury complex: {Chloro-tris[N-methyl-2(3H)-imidazolidine-2- selone]mercury(II)}chloride

A novel cationic Hg(II) complex has been synthesized with N-methyl-imidazolidine-2-selone ligand. The tris(N-Methyl-imidazolidine-2-selone) mercury(II) complex, [(MeImSe)₃HgCl]⁺Cl⁻ (1), has been characterized by single crystal X-ray analysis and CP MAS ¹⁹⁹Hg and ⁷⁷Se NMR.     

Bis(perfluoro-2-n-propoxyethyl)diacyl peroxide initiated homopolymerization of vinylidene fluoride (VDF) and copolymerization with perfluoro-n-propylvinylether (PPVE)

Vinylidenefluoride (VDF) has been homopolymerized and copolymerized with perfluoro-n-propylvinylether (PPVE) using bis(perfluoro-2-n-propoxyethyl)diacyl peroxide (BPPP) as the initiator in CF₂ClCFCl₂. The polymers obtained were characterized with ¹⁹F NMR and ¹H NMR spectroscopy, DSC and TGA. The ¹⁹F NMR spectra were used to determine the polymer microstructures and end groups. Both PVDF and poly(VDF–PPVE) were terminated on both chain ends by CF₃CF₂CF₂OCF(CF₃)∼ arising from the decomposition of the initiator. The concentration of end groups was used to assess the molecular weight of the polymers. Using the Fine–Ross method, the reactivity ratios of both monomers were determined (r_VDF ∼ 1.06, r_PPVE ∼ 0). The T_g of poly(PPVE) (−10.3 °C) was determined using the T_gs of VDF/PPVE copolymers with different compositions and the Flory–Fox equation. A new method to produce a modified PVDF or VDF copolymer for powder coatings with higher thermal stability was also developed.