Search

A novel molecularly imprinted polymer based on tert-butyl acrylate (MIP-BA) was fabricated with the assistance of a cobalt(III)-based catalyst bearing an N-salicylidene isopropylamine ligand [(SPA)2CoCl]. After initiation with methyl aluminoxane, the catalyst system was found to be active toward the polymerization of tert-butyl acrylate (t-BA) in the presence of a polar template (Cibacron reactive red dye) and divinylbenzene (DVB) as a crosslinker. Polymerization experiments, including those of t-BA, t-BA, and DVB and t-BA and dye, were also carried out. Isolated blank polymers and MIP-BA were analyzed with a variety of techniques, including differential scanning calorimetry, thermogravimetric analysis, gel permeation chromatography, infrared spectroscopy, nuclear magnetic resonance, and ultraviolet–visible spectroscopy. In general, the complex showed moderate polymerization activity and produced high-molar-mass poly(tert-butyl acrylate); however, a decrease in the monomer conversion was observed upon the addition of the dye and/or the crosslinker. The effect of imprinting was obvious when the adsorption capacity of MIP-BA measured at pH 6 for red dye (the imprinted molecule) was increased from 9.2 to 90.4 mg/g after imprinting. Competitive adsorption studies revealed that the dye-imprinted polymer enabled the efficient uptake of red dye, even in the presence of blue and yellow dyes that had similar chemical structures to the imprinted molecule. The selectivity coefficients were 43 and 36 with respect to the blue and yellow dyes, respectively. The proposed polymerization procedure could be extended to other anionic polar reactive dyes and polar reactive polymers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Kinetics of oxidation of L-cysteine by CoIII and FeIII complexes based on α- and γ-diimine Schiff base ligands were studied in aqueous solution. Pairs of trans and cis isomers of the metal complexes were used in the studies. Kinetic measurements were performed at 25 °C and constant pH and ionic strength under pseudo-first order condition, in which the concentration of cysteine was around two orders of magnitude greater than that of the metal complex. The observed rate constant was obtained by following the change in absorbance of the reaction mixture with time at a predetermined wavelength. The overall rate constant and order of the reaction with respect to cysteine and metal complex were determined. For both metal ions studied, the oxidation rate constant for the trans isomer was higher than that for the cis isomer. This was attributed to the contribution of the steric factor and the trans effect. The effects of substituents and the nature of the metal ion on the reaction rate are discussed.

Phenolic compounds are one of the most representative pollutants in industrial wastewater, and efficient removals of them have attracted significant concerns. In this study, several commercial and new synthetic polymers (acrylonitrile, 1,3-butadiene, and styrene copolymer (ABS), styrene, acrylonitrile copolymer (SAN), poly(vinyl chloride) (PVC), poly(methyl methacrylate) (PMMA), poly(tert-butyl acrylate) (ptBA)) with special functionalities were evaluated for their ability to remove phenol from an aqueous solution. Equilibrium studies were conducted in the range of 20–100 mg/L initial phenol concentrations, 3–11 pH solutions, and a temperature range of 25–65°C. The results showed that (styrene, 1,3-butadiene) copolymer (SAN) gave the best adsorption capacity among all of the polymers tested. The solution temperature, phenol concentration, and agitation rate played a significant role in influencing the capacity of the adsorbents toward phenol molecules. An increase in solution temperature led to a significant increase in the adsorption capacity of SAN. The percentage of adsorption decreased when initial concentration of phenol increased. However, the percentage removal of phenol was observed to increase with agitation. Removal of phenol using polymeric microbeads is difficult to investigate under high and low pH values because it requires a lot of acid or base to adjust the pH values in the adsorption media. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Water-soluble palladium complexes cis-[Pd(L)(OAc)2] (1–8) (L represents a diphosphine ligands of the general formula CH2(CH2PR2)2, where for a: R (CH2)6OH; b–g: R (CH2)nP(O)(OEt)2, n = 2–6 and n = 8; h: R (CH2)3NH2) have been employed, after activation with a large excess of HBF4, for emulsion polymerization of alkenes (propene, butene, and their equimolar mixtures) with carbon monoxide. Aliphatic polyketone lattices with a high solid content (21%), high molecular weight (6.3 × 104 g mol−1), and narrow polydispersities (Mw/Mn ≈ 2) were isolated. The catalytic activity of the dicationic palladium (II) based catalysts, C1–C8 is highly dependent on the length of the alkyl chain of the ligand. Catalyst 3 proved to be highly active for propene/CO copolymers, whereas 6 is active for butene/CO and propene/CO-butene/CO systems. The presence of methyl β-cyclodextrin, as a phase-transfer agent, and undecenoic acid, as an emulsifier, increase the molar mass and the stability of the polyketones and finally the activity of the catalyst. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6715–6725, 2009

The reaction of (1R,2R)-(–)-1,2-diaminocyclohexane (1) [DACH] with the aldehyde (1R)-(–)-myrtenal (2) in MeOH afforded the bidentate diimine ligand, (1R,2R)-(–)-N1,N2-bis{(1R)-(–)myrtenylidene}-1,2-diaminocyclohexane (3) in a high yield. Reduction of 3 using LiAlH4 led to the formation of the desired ligand (4) (1R,2R)-(–)-N1,N2-bis{(1R)-(–)myrtenyl}-1,2-diaminocyclohexane. Treatment of compound 4 with K2PtCl4 or K2PdCl4 yielded the corresponding platinum(II) and palladium(II) complexes, Pt-5 and Pd-6, respectively. The reaction of compound 3 with K2PtCl4 gave the diimine complex Pt-7. The cytotoxic activity of the complexes Pt-5, Pd-6 and Pt-7 was tested and compared to the approved drugs, cisplatin (Cis-Pt) and oxaliplatin (Ox-Pt). The complexes (Pt-5, Pd-6 and Pt-7) inhibit L1210 cell line proliferation with an IC50 of 0.6, 4.2, and 0.7 μL, respectively as evidenced by measuring thymidine incorporation.

The synthesis of a new series of trans and racemic cis isomers of cobalt(III)-, iron(III)-, and chromium(III)-based complexes with the α- and γ-diimine Schiff base ligands, N,N′-bis(X)-2,3-butandiimine and N,N′-bis(X)-1,2-phenyldiimine (X = cyclohexyl, 2-isopropylphenyl, 1-naphthyl) is described. To confirm the identity of the complexes prepared in the present study, a variety of techniques including elemental analysis, magnetic susceptibility, infrared-, mass- (EI), and UV/Vis- spectroscopy have been utilized. Some of the isolated complexes have been evaluated as catalysts for the oxidation of L-cysteine. Preliminary results showed that the metal atoms, geometry of the complexes, auxiliary substituents, and the backbone of the ligand influenced the rate of oxidation reaction.

Iron(II) and cobalt(II) complexes (7-15) based on new aldimine 2, 6-bis[(imino)methyl]pyridine (1, 2, 4, 6) and ketimine (2, 6-bis[(imino)ethyl]pyridine (3, 5) ligands with bulky chiral aliphatic or aromatic terminal groups have been prepared and characterized by 1H NMR, 13C NMR, IR-, mass spectroscopy (EI), and elemental analysis. The complex [CoCl2(BBoMP)]·1/2 CHCl3 (13) (BBoMP: 2, 6-bis{(R-(+)-(bornylimino)-methyl}pyridine) crystallizes in monoclinic space group P21 with cell dimensions: a = 7.6603(11) A, b = 28.3153(14) A, c = 13.537(2) A, V = 2908.1(6) A3, Z = 4. The coordination sphere around Co is distorted trigonal bipyramidal.

The copolymerization and terpolymerization reactions of the vinyl-substituted phenolic stabilizers, 6-tert-butyl-2-(1,1-dimethylhept-6-enyl)-4-methylphenol, o-allylphenol, 4-methylstyrene-2,6-di-tert-butylphenol and 2,6-di-tert-butyl-4-allylphenol, with propene and carbon monoxide, by using the solvent-stabilized palladium(II) phosphine complex [Pd(dppp)(NCCH3)2](BF4)2 (dppp, 1,3-bis(diphenylphosphino)propane) as a catalyst precursor and methanol as a co-catalyst, is described. The influence of functional α-olefins/CO units, distributed statistically along the propene/carbon monoxide (P/CO) copolymer backbone, on the molecular weight, glass transition temperature (Tg), elastic behavior and stability of the high-molecular-weight P/CO copolymer has been investigated. Loss of both elasticity and transparency were observed upon incorporating o-allylphenol as a termonomer. The terpolymers, which contain phenolic stabilizers, were shown to be more stable when compared to the stabilizer-free polyketones. In contrast to the propene/carbon monoxide copolymer, no degradation was observed for the 2,6-di-tert-butyl-4-allylphenol/P/CO terpolymer; instead, the molar masses increased. Copyright © 2004 Society of Chemical Industry

Synthesis of functional aliphatic polyketones was achieved by co- and terpolymerization of the strained exo-methylenecycloalkane, methylenecyclopropane (MCP), and also the dienes 1,5-hexadiene, 1,7-octadiene and 1,6-heptadien-4-ol, with carbon monoxide and propene, using the dicationic palladium(II) phosphine complex [Pd(dppp) (NCCH3)2](BF4)2 (I) (dppp is 1,3-bis(diphenyl-phosphino)propane) as the catalyst precursor. The resulting MCP/CO copolymer contains both ring-opened and cyclic microstructures. Ring-opening copolymerization yields exo-methylene functionalized polyketone. In contrast to hexadiene/carbon monoxide copolymer (Hx/CO), no ring structures were observed in the alternating octadiene/carbon monoxide (Oc/CO) and heptadien-4-ol/carbon monoxide (Hp-ol/CO) copolymers. The remaining double bonds were left intact to yield polymers with olefinic functionalities in the side chains. © 2001 Society of Chemical Industry

The synthesis and characterization of the unsymmetric hafnium dialkyl [1-(η5-9-fluorenyl)-2-(η5-1-indenyl)ethane]HfCl2 (2) and corresponding dimethyl complex [1-(η5-9-fluorenyl)-2-(η5-1-indenyl)ethane]Hf(CH3)2 (3) is described. The dialkyl hafnocene (3) crystallizes in monoclinic space group P21/c (No. 14) with a = 9.458(8), b = 8.541(8), c = 23.733(11) A, β = 93.16(5) deg., V = 1914(3) A3, Z = 4. Further on, complex 3 was activated with methylaluminiumoxane (MAO) and utilized as a catalyst in ethene polymerization. Synthese und Kristallstruktur von [1-(η5-9-fluorenyl)-2-(η5-1-indenyl)ethan]hafniumdimethyl Die Synthese und Charakterisierung des asymmetrischen Hafniumdialkyls [1-(η5-9-fluorenyl)-2(η5-1-indenyl)ethan]HfCl2 (2) und des entsprechenden Dimethyl Komplexes [1-(η5-9-fluorenyl)-2-(η5-1-indenyl)ethan]Hf(CH3)2 (3) werden beschrieben. Dialkylhafnocen (3) kristallisiert in der monoklinen Raumgruppe P21/c (Nr. 14) mit a = 9.458(8), b = 8.541(8), c = 23.733(11) A, β = 93.16(5)°, V = 1914(3) A3, Z = 4. Komplex 3 wurde mit Methylaluminiumoxan (MAO) aktiviert und als Katalysator in der Ethenpolymerisation eingesetzt.

Structure, properties, and deformation behavior of a high molecular weight propene-CO alternating copolymer (ElPCO 200) and ethene-CO/propene-CO terpolymers (EPEC 1; E-CO = 47% and EPEC 2; E-CO = 69%) were investigated. The terpolymer with high molar ratio of ethene-CO to propene-CO (EPEC 2) is a typical thermoplastic and reveals relatively high crystallinity, while the terpolymer of lower content of ethene-CO groups (EPEC 1) and the propene-CO copolymer (ElPCO 200) exhibit elastomeric behavior. In spite of the possible random stereo- and regioregularity, the propene-CO chains crystallize with regular 3/1 chain conformation. According to X-ray data the synthesized terpolymers consist of blocks of propene-CO segments and blocks enriched with ethene-CO groups. The main structural changes at deformation were studied by means of X-ray diffraction and deformation calorimetry. It is established that the large reversible deformation of the samples studied is determined mostly by the amorphous regions. Deformation calorimetry results, treated according to the modern theory of thermoelasticty of rubber-like materials, showed that the energy contribution (ΔU/W) V.T and the temperature coefficient of the unperturbed dimension of chains d In 0 /dT are more negative than for PE and PP, which seems quite reasonable owing to the chemical structure of the 1,4-polyketone macromolecules.

The synthesis of a benzo-15-crown-5 functionalized α-olefin (4′-(undec-10-enylcarboxylate)benzo-15-crown-5, 5) and its terpolymerization with carbon monoxide and various α-olefins are described. A decline of the glass transition temperatures (Tg) of the corresponding terpolymers was observed upon incorporating compound 5 into the polymer main chain. Ion-selective membranes were prepared by encapsulating the benzo-15-crown-5 functionalized α-olefin/CO terpolymers in a microporous polyethylene support. Preliminary ion-transport experiments demonstrate the ability of these novel crown ether substituted polyketones to transport NaClO4 across the membranes. Adjusting the polarity of the polyketones via the length of the olefinic side chain offers a means to control the ion-permeation-rates.

Highly soluble alternating 1-olefin/carbon monoxide copolymers with olefin monomers (H 2 C=CH-R) containing 4, 5, 6, 10, 14, 16 and 18 C-atoms in the R-substituents were prepared by the use of dicationic palladium(II) phosphine catalysts and an optimized amount of methanol as activator. In terpolymerization experiments the influence of icosene-CO or octadecene-CO units, distributed randomly along a propene-CO or ethene-CO copolymer backbone, on molecular weight, glass transition temperature and on the surface polarity of films casted from solution has been investigated. As the length of the α-olefin side chain increases, the glass transition temperature (T g ) of the copolymer is reduced from room temperature to almost -60°C. For octadecene-CO and icosene-CO copolymers side chain crystallization occurs, leading to elastic materials. Contact angle measurements, performed on water drops located on the surface of selected co- and terpolymer films demonstrate the wide range of surface polarity which can be covered by simple copolymerization of polar CO groups with apolar alkenes.

Soluble propene/ethene/CO terpolymers (EPEC) with ultrahigh molecular weight (up to 1.2 × 106 g/mol) were prepared by the use of dicationic palladium(II) phosphine catalysts and an optimized amount of water as activator. When the molar ratio of ethene/CO to propene/CO is below 50 mol-%, the terpolymers are thermoplastic elastomers with excellent properties. Above this ratio the terpolymers are crystalline thermoplastics. The ultrahigh molecular weight elastomers are highly soluble in organic solvents such as CH2Cl2 and CHCl3.

(1R,2R)-(-)-N,N'-bis(quinoline-2-methylidene)-1,2-cyclo-hexanediamine, C 26 H 24 N 4 , was prepared by the reaction of quinoline-2-carbaldehyde and the corresponding diamine. The crystal structure of the resulting enantiomerically pure quadridentate ligand has been determined.

Carba- d -fructofuranose ( 2a ) was synthesized in 3 steps from cyclopentene 3 . Compound 3 was prepared in 90% yield from commercially available 2,3,5-tri- O -benzyl- d -arabinose. The C-5 hydroxylmethyl unit was incorporated into 3 via hydroformylation using Wilkinson's catalyst. Reduction and hydrogenation afforded carba- d -fructofuranose ( 2a ).

The hydroformylation of glycals was achieved using Rh(I)(acac)(CO) 2 catalyst. For glucals, the C-2 formyl pyran was the major product whilst for galactal an equimolar mixture of the C-2 and C-1 regioisomers were observed.

The phosphorus-sulfur ligand 1-(methylthio)-3-(diphenylphosphino)-propane (S-P3) has been synthesized and characterized by 1H NMR and 13C NMR. Reactions of S-P3 with [PdCl2(PhCN)2] afforded the complexes [PdCl2(S-P3)] (I) and [PdCl2(S-P3)2] (II), in which S-P3 acts as a bidentate and monodentate ligand, respectively. Compound I crystallizes in monoclinic space group P21/n (No. 14) with cell dimensions: a = 8.589(3), b = 15.051(3), c = 17.100(3)A, β = 102.91(2)°, V = 2154.7(9)A3, Z = 4. Likewise, compound II crystallizes in monoclinic space group P21/n (No. 14) with a = 9.993(5), b = 8.613(4), c = 18.721(5)A, β = 90.18(3)°, V = 1611.3(12)A3, Z = 2. Compound II has a trans square planar configuration with only the P-site of the ligand bonded to the palladium atom. Palladium(II)-Komplexe mit dem zweifachen Donor-Liganden CH3S-(CH2)3-PPh2 Kristallstruktur von [PdCl2{CH3S-(CH2)3-PPh2}n](n = 1, 2) Der Phosphor-Schwefel-Ligand 1-(Methylthio)-3-(diphenylphosphino)propan (S-P3) wurde synthetisiert und durch 1H- und 13C-NMR-Spektroskopie charakterisiert. Die Reaktionen von S-P3 mit [PdCl2(PhCN)2] fuhren zu den Komplexen [PdCl2(S-P3)] (I) und [PdCl2(S-P3)2] (II), in denen S-P3 als zweiz”hniger bzw. einz”hniger Ligand fungiert. Verbindung I kristallisiert monoklin in der Raumgruppe P21/n (Nr. 14) mit den Zelldimensionen a = 8, 589(3), b = 15, 051(3), c = 17, 100(3)A, β = 102, 91(2)°, V = 2154, 7(9)A3, Z = 4. II kristallisiert ebenfalls monoklin in der Raumgruppe P21/n (Nr. 14) mit a = 9, 993(5), b = 8, 613(4), c = 18, 721(5)A, β = 90, 18(3)°, V = 1611, 3(12)A3, Z = 2. Verbindung II hat eine quadratisch-planare trans-Konfiguration, in der die Ligand-Molekule nur uber das P-Atom an das Palladium-Atom gebunden sind.