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A first-time, end group thermolysis departing a urethane into propylene carbonate. This exposure produced a new amine tethering point producing a diamine-terminated oligourea ([10]-OU) as a green sorbent for CO2 capturing is reported.

Transition metal complexes of the general formula [(S∩N∩N∩S)MCl2] (M: Cr(II), 2; Fe(II), 3, Co(II); 4; (S∩N∩N∩S): cis-1,2-N1,N2-bis{(benzo[b]thiophen-2-yl)methylene-diaminocyclohexane, S-DACH, 1) were prepared and characterized. The new complexes have been utilized as catalysts for the coupling reaction of carbon dioxide and the epoxides, styrene oxide (SO), and (±)-propylene oxide (PO), in the presence of bis(triphenylphosphoranylidene)imminium bromide (PPNBr) as a co-catalyst. The reactions were carried out under relatively low pressure and solvent-free conditions. The catalyst systems showed to be selective for the formation of cyclic carbonates. In general, the Cr(II)-based catalyst exhibited the highest activity for the coupling reaction of CO2 with both SO and (±)-PO compared with the corresponding iron(II) and cobalt(II) complexes under similar reaction conditions with turnover numbers values of 2445 and 1164 for the production of propylene carbonate and styrene carbonate, respectively.

Kinetics of oxidation of L-cysteine by new series of substituted ONNO-donor salen-type Schiff base complexes of general formula [MIII(L)Cl] (M = Co, Fe, Cr; L = Schiff base ligand) have been studied in aqueous solutions. Measurements were run at constant temperature (25º C), constant ionic strength (0.20 M), and constant pH (7.0) under pseudo-first order conditions, in which the concentration of cysteine is around two orders of magnitude greater than that of metal complex. The observed rate constant was determined by following the change in absorbance of reaction mixture at a predetermined wavelength with time. Results show that the rate of oxidation depends on the type of metal center, with Co(III) complexes were found to have the highest rates due to higher reduction potential of Co(III). The oxidation rate was also found to depend on steric factor and the electron withdrawing / releasing ability of the ligand bound to the metal ion.

The synthesis and characterization of substituted ONNO-donor salen-type Schiff base complexes of general formula [MIII(L)Cl] (L�=�Schiff base ligand, M�=�Fe, Co) is reported. The complexes have been applied as catalysts for the coupling of carbon dioxide and styrene oxide in the presence of tetrabutylammonium bromide as a co-catalyst. The reactions were carried out under relatively low-pressure and solvent-free conditions. The effects of the metal center, ligands, and various substituents on the peripheral sites of the ligand on the coupling reaction were investigated. The catalyst systems were found to be selective for the coupling of CO2 and styrene oxide, resulting in cyclic styrene carbonate. The cobalt(III) complex with no substituents on the ligand showed higher activity (TON�=�1297) than the corresponding iron(III) complex (TON�=�814); however, the iron(III)-based catalysts bearing electron-withdrawing substituents on the salen ligands (NEt3, TON�=�1732) showed the highest catalytic activity under similar reaction conditions. The activity of one of the cobalt(III) complexes toward the coupling of 1-butene oxide, cyclohexene oxide and propylene oxide with CO2 was evaluated, revealing a notable activity for the coupling of 1-butene oxide. Scopus

New alternating poly(propylene- alt -carbon monoxide/ethylene- alt -carbon monoxide) (PECO)/multiwalled carbon nanotubes (MWCNTs) composites have been prepared. Dielectric permittivity, electric modulus and ac conductivity of the isolated materials were investigated as a function of fiber aspect ratio, frequency and temperature. For aspect ratio of 30 and 200, a transition from insulator to semiconductor was observed at frequency 1×10 4 . However, for high aspect ratio sample (660), no transition was observed and the conductivity is frequency independent in the measured frequency range of 10–10 6 Hz. The conductivity increases from about 1×10 −4 for the sample that contain fibers of aspect ratio 30 and reaches 5×10 −2 (Ω m) −1 for aspect ratio was 660. This behavior can be modeled by a circuit that consists of a contact resistance in series with a parallel combination of resistance ( R ) and capacitance ( C ). The calculated activation energy for sample filled with fibers having aspect ratio 30 is about 0.26 eV and decreases to about 0.16 eV when the aspect ratio is 660.

Impedance spectroscopy was utilized to investigate the dielectric properties, ac conductivity and charge transport mechanisms in propylene-alt-CO/ethylene-alt-CO (EPEC) random terpolymer filled wit...

A series of chromium(III)-, cobalt(III)-, and iron(III)-based complexes of the general formula [(N∩O)2MCl] (1–7) (N∩O: N-salicylidene(R)amine, R = 1-naphthyl or cyclohexyl) have been applied as catalysts for the coupling reaction of carbon dioxide and epoxystyrene (styrene oxide) in the presence of tetrabutylammonium bromide (Bu4NBr) as a cocatalyst. The reactions were carried out under relatively low pressure and solvent-free conditions. In addition, iron complexes (8–10) containing the ligands, N′-(thiophene-2-methylene)benzene-1,2-diamine, (8), N′-(quinoline-2-methylene)benzene-1,2-diamine (9), and sodium N-(4-sulfonato-salicylidene)-1,2-phenylenediamine (10) were also utilized for the catalytic reaction. The influence of metal center, ligand, temperature, and reaction time on the coupling reaction was investigated. The catalyst systems proved to be selective in the coupling reaction of CO2 and styrene oxide, resulting in cyclic styrene carbonate. In general, the iron(III)- and cobalt(III)-based catalysts bearing the aromatic 1-naphthyl terminal groups showed the highest catalytic activity under similar reaction conditions.

The electrical properties of elastic alternating propylene–carbon monoxide copolymer (PCO-200) were investigated using the impedance spectroscopy technique. The results revealed a phase transition at about 70 °C where the material transforms from its insulating phase of conductivity in the order of 6×10−9 to about 9×10−5 (Ω m)−1, The second phase is characterized by temperature dependent electrical relaxation phenomena. The plot of the complex electric modulus and the complex impedance yields semicircles in the temperature range 70 up to 110 °C and a decreasing radius with increasing temperature. The activation energy was found to be in the order of 0.8 eV.

Electrical impedance technique was employed to investigate the electrical properties of ethylene-carbon monoxide/propylene-carbon monoxide terpolymer (EPEC-69). The measurements were performed in the frequency range 0.1–105 Hz and in the temperature range 30–110 °C. The results reveal that the dielectric constant, loss factor, modulus, and ac conductivity are dependent of frequency and temperature. A Debye relaxation peak was detected in the plot of Z″ versus frequency where the activation energy was determined and found to be 1.26 eV. When the surface phenomenon effects were separated using the imaginary part of the complex admittance a second dielectric dispersion was observed in the low frequency region. Two models were proposed from the impedance measurements depending on temperature range.

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

2,6-bis[1-(cis)-myrtanylimino)ethyl]pyridineiron(II) chloride (2) and 2,6-bis[(1-phenylimino)ethyl]pyridineiron(II) chloride (3) were investigated as novel complexes for iron-mediated atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) and tert-butyl acrylate (tBA) using toluene as the solvent, and ethyl 2-bromoisobutyrate as the initiator. A catalyst/initiator molar ratio as low as 0.1/1 was used in order to reduce catalyst contamination to the polymers. Both complexes produced PMMA and PtBA polymers with controlled structures and very low molecular weight distributions as low as 1.07, in particular for complex 3. High to moderate conversions (30–45%) were obtained in 20 h, although very diluted amount of catalyst was used and in the absence of any reducing agent which indicates an efficient catalyst system. The resulting polymers were characterized by NMR, GPC, and DSC. Syndio-rich atactic poly(t-BA) and poly(MMA) with relatively high [rr] diads (50%, 42%, respectively) were isolated.

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

Aldimine 2,6-bis[(imino)methyl]pyridine iron(II) (1, 4, and 6) and cobalt(II) (3 and 5) complexes bearing bulky cycloaliphatic (bornyl and myrtanyl) or aromatic (naphthyl) terminal groups have been applied successfully, after activation with methyl aluminoxane (MAO), as catalysts for the polymerization of tert-butylacrylate. For comparison reasons, complex 2 that contains the ketimine ligand, 2,6-bis[(−)-cis-myrtanylimino)ethyl]pyridine (BMEP), has also been utilized. All studied complexes showed moderate polymerization activities, and they produced high molar mass syndiorich-atactic polymers. Surprisingly, the aldimine-based catalyst systems showed comparable activities compared with the corresponding ketimine complex (2), and they produced high molar mass polymers. In addition, complexes with bulky terminal cycloaliphatic substituents on the tridentate aldimine ligands showed higher polymerization activity compared with the aromatic ones (6). Polymerization activity and polymer molar masses are dependent on the ligand framework.

A new series of penta-coordinated Co(III)-, Fe(III)-, and Cr(III)- complexes (6–10) bearing N-salicylidineisopropylaniline and sodium N-(4-sulfonitsalicylidineisopropyl-aniline) ligands has been synthesized and utilized, after activation with methyl aluminoxane, as catalysts for the polymerization of tert-butylacrylate (t-BA). High molar mass P(t-BA) polymers with very low molecular weight distributions were produced (M w/M n = 1.06–1.09). Cobalt- and chromium-based precatalysts showed higher activity towards the polymerization reaction than those of the iron complexes. The presence of sulfonated groups on the para position of the aryl group in the backbone of the ligand decreases the catalytic activity of the complexes. The ortho alkyl substituents on the aryl groups of the ligand have a favorable influence on the polymerization activity compared to the alkyl-free analogue (11).

Selective polymeric extractants were prepared for preconcentration of Cibacron reactive red dye, a dye that is often applied with Cibacron reactive blue and Cibacron reactive yellow for dyeing of fabrics. The best extractant was fabricated (in chloroform) using methacrylic acid (as monomer), ethylene glycol dimethacrylate (as crosslinker), AIBN (as initiator for polymerization), and red dye as template molecule, with a molar stoichiometric ratio of 8.0:40.0:2.5:0.63, respectively. The structure of the molecularly imprinted polymer (MIP) was robust, and resisted dissolution up to 260 degrees C. Compared with the un-imprinted polymer, the imprinted product has a large specific surface area which improved its adsorption capacity. The effect of imprinting was obvious from the adsorption capacity measured at pH 4 for red dye (the imprinted molecule), which was increased from 24.0 to 79.3 mg g(-1) after imprinting. Equilibrium adsorption studies revealed that the dye-imprinted-polymer enables efficient extraction of red dye even in the presence of blue and yellow dyes which have similar chemical natures to the red dye. The selectivity coefficients S (red dye/dye), were 13.9 and 17.1 relative to the yellow and blue dyes, respectively. The MIP was found to be effective for red dye preconcentration, with a preconcentration factor of 100, from tap water and treated textile wastewater. The factors affecting extraction of red dye by the MIP were studied and optimized. Under the optimized extraction conditions, red dye was selectively quantified in the presence of other competing dyes at a concentration of 20 microg L(-1) from different water systems with satisfactory recoveries (91-95%) and RSD values (approximately 5.0%).

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.

A series of new cobalt(III)-, iron(III)-, and chromium(III)-based complexes of the general formula [M(N∩O)2Cl] (N∩O: N-salicylidene(X)amine and sodium N-(4-sulfonatosalicylidene(X)amine)) (X = cyclohexyl and 1-naphthyl) was prepared and characterized. Some of the isolated complexes have been evaluated as catalysts for the oxidation of L-cysteine. Preliminary results show that the rate of oxidation of L-cysteine is influenced by the nature of the metal center, the geometry of the complex, the auxiliary substituents, and the backbone of the ligand.

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.

cis-Dichloro-palladium(II) andcis-dichloro-platinum(II) complexes (2,4) of the general formula [M(N-N)Cl2] (M=Pd(II) and Pt(II), N-N= 1,2-diamino-4-fluoro-5-(4-methyl-1-piperazinyl) benzene, (DFMPB)) and the dicationic palladium(II) complex [Pd(N-N)(CH3CN)2](BF4)2(3) have been prepared and characterized by elemental analysis,1H-NMR-, mass spectroscopy, and IR spectroscopy. The cytotoxic effect of these complexes against MDA-231 and MCF-7 human breast cancer cell lines and K562 human leukemia cell line has been studied. The influence was dose dependent and varies with cell type. The palladium(II) complex (2) showed superior cytotoxic effect compared with the corresponding platinum(II) complex and the standard, cisplatin, when tested against all the above cell lines.

A series of iron(II) complexes ( 4a–d , 10 , and 11 ) bearing 2,6-bis[(imino)ethyl]pyridine-( 3a–d ), quinolinaldimine-( 8 ) and thiophenaldimine-( 9 ) based ligands were disclosed as active complexes for the polymerization of tert -butylacrylate ( t -BA). After activation with methyl aluminoxane (MAO), the complexes showed moderate to high polymerization activities and produced high molar mass polymers. In addition, the catalyst system 4d /MAO was examined for the polymerization of methyl methacrylate (MMA) and n -vinylcarbazole (NVC). The influence of MAO/Cat. molar ratio, polymerization time, and monomer concentration on the polymerization reaction of methyl methacrylate was explored. In the polymerization of tert -butylacrylate with 2,6-bis[(imino)ethyl]pyridine iron(II)-based catalysts, bulky terminal aliphatic substituents have a favorable influence on the polymerization activity compared to the aromatic ones. This catalyst system was also more active than the quinolinaldimine-, ( 10 ) and thiophenaldimine-, ( 11 ) based catalysts.

Kinetics of oxidation of L-cysteine by pairs of trans and racemic cis isomers of cobalt(III) and iron(III) based transition metal complexes have been studied in aqueous solution. Kinetics measurements were run under pseudo first order conditions in which the concentration of cysteine is between one and two orders of magnitude greater than that of the isomers of the transition metal complex. The orders of the reaction with respect to both cysteine and the isomer were determined. The observed rate constants and the overall rate constants of the oxidation process were measured. For all geometrical isomers, it was found that the rate constant of oxidation of L-cysteine by the trans isomer is between one to three orders of magnitude greater than that by the cis isomer. The difference in rates can be explained by a geometric factor around the metal ion center in the complex. The less crowded isomer (trans) makes electron transfer easier and hence facilitates the oxidation process which leads to a higher oxidation rate.

In the next two decades, the world is expected to see around 20 million cases of cancer. Moreover, the types of cancer will vary considerably from country to other. Therefore, all efforts will be needed to face such a vast diversity of problems. With current annual sales of about $500 millions, the platinum(II) complex known as cisplatin [cis-(NH3)2PtCl2] is still one of the most effective drugs to treat testicular, ovarian, bladder and neck cancers. Since it was launched in 1978 there has been a rapid expansion in research to find new, more effective metal-based anticancer drugs and to study their interactions with biological systems. This study gives an up to date overview of the anticancer chemistry of the platinum group elements platinum, palladium, and nickel with an emphasis on the new strategies used in the development of new antitumor agents. Methodologies for application of bulky aromatic or aliphatic nitrogen ligands, chiral organic moieties, chelates containing other donor atoms than nitrogen, and biologically active ligands in the design of agents analogous to cisplatin are presented. The review also aims to highlight the class of the unconventional complexes that violate the empirical structure-activity rules (SAR) of platinum compounds and the common features and structural differences between the most successful anticancer complexes that are currently in human clinical trials.

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

Four tetradentate nitrogen ligands, viz. dichloro{[N,N′-diphenyl-N,N′-di(quinoline-2-methyl)]-1,2-ethylene diamine} (1), {[N,N′-dioctyl-N,N′-di(quinoline-2-methyl)]-1,2-ethylene diamine} (2), {[N,N′-dibenzyl-N,N′-di(quinoline-2-methyl)]-1,2-ethylene diamine} (3), and (1R,2R)-(−)-N,N′-di(quinoline-2-methyl) di-iminocyclohexane (4), were investigated as novel complexing ligands in iron-mediated atom transfer radical polymerization (ATRP) of methyl methacrylate where ethyl-2-bromoisobutyrate was the initiator in o-xylene at 90 °C. With ligands 1 and 2 the experimental molecular weights increased gradually with monomer conversion. High to moderate conversions (87%, 43%) were obtained in relatively short times (90 min for 1 and 30 min for 2), which indicates an efficient catalyst system, but after these times a dramatic increase in viscosity of the polymerization medium led to loss of control. It is noteworthy that polymerization proceeded in a controlled manner with ligand 1, which has two rather bulky substituents on the N-atom. Such bulky ligands did not work for a copper-based system, where they led to excessive terminations or other side reactions. When the bulkiness of the substituents was significantly increased, as in ligand 3, a decrease in polymerization rate and loss of control occurred. Ligand 4 was less efficient than the other ligands, probably because the ethylene bridge was replaced by cyclohexane bridge.

A series of salicylketimines (2-[(2,6-diisopropylphenylimino)ethyl]phenol, 2-[(2,6-diisopropylphenylimino)ethyl]naphthol and 2-[(2,6-diisopropylphenylimino)(phenyl)-methyl]phenol), and their nickel complexes of general forms [(salicylketiminato)-Ni(PPh3)(Ph)] and [(salicylketiminato)2Ni] were synthesized and characterized. The formation of monophenyl-nickel(II) complexes versus the corresponding bis(sal)Ni(II) complexes depends on the fine tuning of the reaction work up and is affected by the substituent at the ketimine. Salicylketimines were thus found to form more readily the bis(sal)Ni(II) complexes than salicylaldimines. The molecular structures of the complexes were determined by X-ray crystallography and in all of them Ni has a nearly ideal square-planar coordination sphere.

The nucleophilic substitution reaction of the enantiomerically pure ligand, (1R,2R)-(−)-1,2-diaminocyclohexane [DACH] (1) with cis-bis(benzonitrile)palladium(II) dichloride [(PhCN)2PdCl2] leads to the formation of the complex [(DACH)PdCl2] (2) in a high yield. The reaction of the corresponding platinum(II) complex [(PhCN)2PtCl2] with DACH, under the same reaction conditions, surprisingly, took a different course, in which nucleophilic addition to the benzonitrile ligand occurred forming an enantiomerically pure amidine complex [(PhCNHNH(C6H10)NH2)Pt(NCPh)Cl]Cl (3), where the nitrogen ligand form a seven-membered chelate around the central atom. The aqua and oxalato derivatives of complex 2, [(DACH)Pd(H2O)2](NO3)2 (4) and [(DACH)Pd(C2O4)] (5) have also been prepared and characterized. The platinum analogue complex to 5, [(DACH)Pt(C2O4)] (6), was prepared starting from the enantiomerically pure isomer (1) and the platinum salt K2PtX4 (X=Cl, I). According to X-ray structural analysis carried out on the complex, the product does not consist of just the desired isomer, but a mixture of both the trans-l (trans-(−)-1R,2R) and trans-d (trans-(+)-1S,2S) isomers. No retention of optical isomerism was observed. The single crystal structural analysis was also carried out on the ligand N,N′-(1R,2R)-(−)-diaminocyclohexane dihydrochloride (DACH·2HCl)] (1a). The result indicates, however, that only the R,R-isomer exists in the free ligand.

The synthesis of a new series of iron(II)- and cobalt(II)-based complexes of the general formula M(N∩N∩N)Cl 2 (M=Fe; M=Co) bearing 2,6-bis(imin)pyridyl ligands [A–NC–Py–CN–A] that carry bulky, alkyl-free aromatic terminals (A=naphthyl, pyrenyl, 2-benzylphenyl, phenyl) or chiral cycloaliphatic auxiliary moieties (A=((−)- cis -myrtanyl) is described. The Fe(II) complexes are exceptionally active (up to 40800 kg PE/(mol M h) towards the polymerization of ethylene in the presence of methylaluminoxane (MAO) as activator. Varying the steric bulkiness of the aromatic groups in the tridentate ligands affects catalytic productivity, molecular weight and for the first time the microstructure of the resulted material. The Fe(II) precatalysts are an order of magnitude more active than the corresponding Co(II) precatalysts.

A synthesis of new chiral dihalo palladium(II)-(5, 7) and nickel(II) (6, 8) complexes bearing the ligands N,N′-bis{(−)-(cis)-myrtanyl}butylene-2,3-diimine (BMDI, 3) and the conformationally constrained bisoxazoline ligand ((1R,2S)-inda-box, 4) is described. Reaction of [(TMEDA)Pd(CH3)Cl] (TMEDA: N,N,N′,N′-tetramethylethylenediamine) with 4 followed by chloride abstraction with NaB(Arf)4 in the presence of CH3CN afforded the solvent stabilized, monoalkyl complex [(4)Pd(NCCH3)(CH3)]B(Arf)4 (9) (Arf: 3,5-bis(trifluoromethyl)benzene). The solid state structure of the dichloro palladium(II) complex [{(1R,2S)-inda-box}PdCl2] (7) was determined by X-ray structure analysis.

A new series of [n]-oligoureas ([n]-OUs, n=4, 7, 10, and 12) green solid sorbents was prepared following a base-catalyzed, microwave-assisted oligomerization reaction. The materials were characterized by NMR and IR spectroscopy, elemental analysis, thermogravimetric analysis, differential scanning calorimetry, and XRD. Decomposition temperatures at 50 % weight loss (Td50 ) were ca. 350 °C for all oligomers. Urea and urethane functional groups indicated by IR spectroscopy confirmed the formation of the sorbent. The CO2 capturing capacities were determined at 35 °C and 1.0 bar (gravimetric method). Accordingly, [10]-OU had the highest CO2 sorption capacity among the others (18.90 and 22.70 mg CO 2 gsorbent (-1) ) at two different activation temperatures (60 or 100 °C, respectively). Chemisorption was the principal mechanism for CO2 capture. Cyclic CO2 sorption/desorption measurements were carried out to test the recyclability of [10]-OU. Activating the sample at 60 °C, three stable CO2 sorption cycles were achieved after running the first cycle.

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.

Palladium(II) complexes of the general type [Pd(L∩L)Cl2] (4–6) and their corresponding dicationic complexes [Pd(L∩L)(NCCH3)2](BF4)2 (7–9) (L∩L=[(1-(thiomethyl)-2-(diphenylarsino)ethane] (S∩As, 1) (4, 7) [1-(thiomethyl)-2-(diphenylphosphino)ethane] (S∩P, 2) (5, 8) and [1,2-bis(diphenylphosphino)ethane] (P∩P, 3) (6, 9) have been synthesized and utilized as catalysts for the polymerization reaction of bicyclo[2.2.1]hept-2-ene (norbornene). The dichloride complexes can be activated with methylaluminoxane (MAO), while the corresponding dicationic compounds were used as single component catalysts for the polymerization reactions. Catalytic performance of the new type of catalyst can be altered by modifying the donor atoms in the bidentate ligand. The activity of the Pd(II) complexes towards the polymerization reaction increases with increasing the trans-influence of the donor atoms (P∩P>S∩P>S∩As). The influence of donor atoms on the length of the PdCl bonds was elucidated by X-ray structure analysis carried out on the palladium(II) complex [Pd(S∩As)Cl2] (4).

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.

A synthesis for a series of tetrapodal nitrogen ligands (N,N′-dibenzyl-N,N′-di(quinoline-2-methyl)-1,2-ethylene diamine (DBQED, 1), N,N′-dimethyl-N,N′-di(quinoline-2-methyl)-1,2-ethylene diamine (DMQED, 2), (1R,2R)-(−)-N,N′-di(quinoline-2-methylene) diiminocyclohexane (DQEDC, 3), N,N′-di(quinoline-2-methylene)-1,2-phenylene diimine (DQPD, 4) and for their corresponding neutral and cationic palladium(II) complexes of the types [(1,2,4)PdCl2] (5a, 6a, 7) and [(1,2,3,4)Pd(NCCH3)x](Y)2 (5b, 5c, 6b, 6c, 8, 9), x=0, 2; Y=BF4 −, NO3 − is reported. The dicationic palladium(II) complex [Pd(DBQED)(NO3)2·H2O] (5c) crystallizes in the monoclinic space groups P21/c (no. 14) with a=11.458(1), b=15.302(1) A, c=20.644(2) A, β=99.23(1)° and V=3572.7 A3, Z=4. All four nitrogen donors are attached to the Pd(II)-center in the chiral and C2-symmetric complex 5c. The two quinoline nitrogen atoms of the more rigid Schiff bases (DQEDC, 3; DQPD, 4) do not coordinate coincidentally to Pd(II). A fluxional coordination behavior is suggested for these quinoline donors, which enables this new complex family to act as catalysts for norbornene polymerization, even when chloride is present as a counter ion. Introduction of an enantiomerically pure trans-1,2-cyclohexyl bridge into the Schiff base ligand systems afforded the formation of partially stereoregular polynorbornene.

The moderate electrophilicity of palladium(II)-phosphine catalysts compared to those of zirconocene dichlorides makes them more tolerant toward a variety of polar functionalities of olefinic monomers. This allows use of Pd(II) complexes as catalysts for the copolymerization of olefins with readily available polar monomers, like acrylic acid derivatives or carbon monoxide. In particular, developments during the recent years have opened the way to a new and broad family of high molecular weight 1-olefin/CO co- and terpolymers. These 1,4-polyketone materials show interesting and easily variable properties which can be tuned from insoluble, highly crystalline to thermoplastic elastic. The latter polymers resemble in some cases flexible PVC and even vulcanized natural rubbers.

Novel moisture and air stable, cationic palladium(II) amine complexes ( 1 – 4 ) of the general type [Pd(N∩N)(X) 2 ](BF 4 ) 2 , [N∩N=1,2-bis( N -indolinyl)ethane (BIE) 1 , 3 ; 1,2-bis( N -1,2,3,4-tetrahydroquinolinyl)ethane (BTQE) 2 , 4 ; X=NCCH 3 , H 2 O] were found to catalyze the polymerization reaction of bicyclo[2.2.1]hept-2-ene at room temperature. The amorphous polymer products consist of 2,3-linked norbornene units; no indications for ring opened species could be observed. The polymerization activity of the diaqua-complexes 3 , 4 is superior compared to their acetonitrile analogues due to a facile activation by a Wacker-type reaction. The cationic Pd(II)-compounds are inactive towards homo- and copolymerization reactions of polar monomers, like acrylates or carbon monoxide. However, addition of methylacrylate resulted in polynorbornene products with increased molecular weight and narrow molecular weight distributions.

Treatment of cis-[Pt(dmso)2Cl2] with 2 mol of KBr or KI leads to the formation of the analogous dibromide or diiodide complexes. Treatment of [M(dmso)2Cl2] [M = Pt (cis-) or Pd (trans-)] with AgNO3 (2 mol) in H2O followed by 1mol of potassium oxalate, maleate, cyclobutane dicarboxylate (CBDC), malonate or 2mol of potassium cyclohexane carboxylate or pivalate leads to the formation of the corresponding PtII and PdII carboxylate complexes. The single crystal X-ray structure determination of [Pt(dmso)2(CBDC)] has been discussed and compared with data on other related complexes. The in vitro cytotoxic activity of some of these complexes against eight tumour cell lines has been examined using the MTT-colorimetric assay.

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.

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.

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 ).