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Chloride Complex (chloride + complex)
Selected AbstractsPalladium(II) Chloride and a (Dipyridin-2-ylmethyl)amine-Derived Palladium(II) Chloride Complex as Highly Efficient Catalysts for the Synthesis of Alkynes in Water or in NMP and of Diynes in the Absence of ReoxidantEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 19 2005Juan Gil-Moltó Abstract The (dipyridin-2-ylmethyl)amine-derived palladium chloride complex 1 and PdCl2 are efficient catalysts for cross-coupling reactions between terminal alkynes and aryl iodides or bromides under modified Sonogashira,Cassar,Heck conditions. The alkynylation can be performed under copper-free conditions in water at reflux or at room temperature under air with pyrrolidine as base and tetra- n -butylammonium bromide (TBAB) as additive, with TONs of up to 7,×,104 and TOFs(h,1) of up to 6666. Terminal alkynes can be arylated in NMP as well under copper- and amine-free conditions at 110 °C or room temperature, with tetra- n -butylammonium acetate (TBAA) acting as base with TONs up to 2,×,105 and TOFs (h,1) up to 66,666. In general, complex 1 displays a slightly higher efficiency than PdCl2 as catalyst and maintains the same activity after five consecutive runs. Alternatively, these alkynylation processes can be carried out under microwave heating conditions. The homocoupling of terminal alkynes to the corresponding 1,3-diynes proceeds under phosphane-free conditions with the (dipyridin-2-ylmethyl)amine-derived palladium chloride complex 1 or with PdCl2 as catalysts and with CuI as cocatalyst in NMP with use of either TBAA or pyrrolidine as bases. This Glaser-type reaction can be performed at 110 °C or at room temp. in the presence of air without the use of a reoxidant. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Highly Active, Well-Defined (Cyclopentadiene)(N-heterocyclic carbene)palladium Chloride Complexes for Room-Temperature Suzuki,Miyaura and Buchwald,Hartwig Cross-Coupling Reactions of Aryl Chlorides and Deboronation Homocoupling of Arylboronic AcidsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2009Zhong Jin Abstract A new class of well-defined N-heterocyclic carbene (NHC)-(cyclopentadiene)palladium chloride complexes such as CpPd(NHC)Cl wasw synthesized from the readily available starting NHC-palladium(II) chloride dimers. These air-stable, coordinatively saturated NHC-Pd complexes bearing the cyclopentadiene (Cp) unit exhibit high catalytic activity in the room temperature Suzuki,Miyaura and Buchwald,Hartwig cross-coupling reactions involving unactive aryl chlorides as the substrates. In addition, they are found to be extremely efficient catalysts in the deboronation homocoupling of arylboronic acids at room temperature. [source] Titanium(IV) Chloride Complexes with Chiral Tetraaryl-1,3-dioxolane-4,5-dimethanol Ligands as a New Type of Catalysts of Ethylene Polymerization.CHEMINFORM, Issue 33 2006Yu. N. Belokon' Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Palladium(II) Chloride and a (Dipyridin-2-ylmethyl)amine-Derived Palladium(II) Chloride Complex as Highly Efficient Catalysts for the Synthesis of Alkynes in Water or in NMP and of Diynes in the Absence of ReoxidantEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 19 2005Juan Gil-Moltó Abstract The (dipyridin-2-ylmethyl)amine-derived palladium chloride complex 1 and PdCl2 are efficient catalysts for cross-coupling reactions between terminal alkynes and aryl iodides or bromides under modified Sonogashira,Cassar,Heck conditions. The alkynylation can be performed under copper-free conditions in water at reflux or at room temperature under air with pyrrolidine as base and tetra- n -butylammonium bromide (TBAB) as additive, with TONs of up to 7,×,104 and TOFs(h,1) of up to 6666. Terminal alkynes can be arylated in NMP as well under copper- and amine-free conditions at 110 °C or room temperature, with tetra- n -butylammonium acetate (TBAA) acting as base with TONs up to 2,×,105 and TOFs (h,1) up to 66,666. In general, complex 1 displays a slightly higher efficiency than PdCl2 as catalyst and maintains the same activity after five consecutive runs. Alternatively, these alkynylation processes can be carried out under microwave heating conditions. The homocoupling of terminal alkynes to the corresponding 1,3-diynes proceeds under phosphane-free conditions with the (dipyridin-2-ylmethyl)amine-derived palladium chloride complex 1 or with PdCl2 as catalysts and with CuI as cocatalyst in NMP with use of either TBAA or pyrrolidine as bases. This Glaser-type reaction can be performed at 110 °C or at room temp. in the presence of air without the use of a reoxidant. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Redox properties of the couple compound I/native enzyme of myeloperoxidase and eosinophil peroxidaseFEBS JOURNAL, Issue 19 2001Jürgen Arnhold The standard reduction potential of the redox couple compound I/native enzyme has been determined for human myeloperoxidase (MPO) and eosinophil peroxidase (EPO) at pH 7.0 and 25 °C. This was achieved by rapid mixing of peroxidases with either hydrogen peroxide or hypochlorous acid and measuring spectrophotometrically concentrations of the reacting species and products at equilibrium. By using hydrogen peroxide, the standard reduction potential at pH 7.0 and 25 °C was 1.16 ± 0.01 V for MPO and 1.10 ± 0.01 V for EPO, independently of the concentration of hydrogen peroxide and peroxidases. In the case of hypochlorous acid, standard reduction potentials were dependent on the hypochlorous acid concentration used. They ranged from 1.16 V at low hypochlorous acid to 1.09 V at higher hypochlorous acid for MPO and from 1.10 V to 1.03 V for EPO. Thus, consistent results for the standard reduction potentials of redox couple compound I/native enzyme of both peroxidases were obtained with all hydrogen peroxide and at low hypochlorous acid concentrations: possible reasons for the deviation at higher concentrations of hypochlorous acid are discussed. They include instability of hypochlorous acid, reactions of hypochlorous acid with different amino-acid side chains in peroxidases as well as the appearance of a compound I,chloride complex. [source] Reduction of Alkyl Halides by Triethylsilane Based on a Cationic Iridium Bis(phosphinite) Pincer Catalyst: Scope, Selectivity and MechanismADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2009Jian Yang Abstract A highly efficient procedure for the reduction of a broad range of alkyl halides by triethylsilane based on a cationic iridium bis(phosphinite) pincer catalyst has been discovered and developed. This reduction chemistry is chemoselective and has unique selectivities compared with conventional radical-based processes and the aluminum trichloride/triethylsilane (AlCl3/Et3SiH) and triphenylmethyl tetrakis[pentafluorophenyl]borate/triethylsilane {[Ph3C] [B(C6F5)4]/Et3SiH} systems. Reductions use three equivalents of triethylsilane relative to the halide and can be carried out with very low catalyst loadings and in a solvent-free manner, which may provide an environmentally attractive and safe alternative to many currently practiced methods for reduction of alkyl halides. Mechanistic studies reveal a unique catalytic cycle. The cationic iridium hydride 2,6-bis[di-(tert -butyl)phosphinyloxy)phenyl(hydrido)iridium, (POCOP)IrH+ {POCOP= 2,6-[OP(t- Bu)2]2C6H3} binds and activates the silane. This complex serves as a potent silylating reagent to generate silyl halonium ions, Et3SiXR+, which are reduced by the neutral iridium dihydride to yield alkane product and regenerate the cationic (POCOP)IrH+, thus closing the catalytic cycle. All key intermediates have been identified by in situ NMR monitoring and kinetic studies have been completed. An application of this reduction system to the catalytic hydrodehalogenation of a metal chloride complex is also described. [source] Aerobic, Chemoselective Oxidation of Alcohols to Carbonyl Compounds Catalyzed by a DABCO-Copper Complex under Mild ConditionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2007Sreedevi Mannam Abstract A DABCO-copper(I) chloride complex (5 mol,%) together with TEMPO (5 mol,%) in nitromethane as solvent has been used as an efficient catalytic system for the selective oxidation of benzylic and allylic alcohols into the corresponding carbonyl compounds at room temperature where molecular oxygen acts as an ultimate, stoichiometric oxidant and water is the only by-product. The solid-state structure determination of the DABCO-copper complex shows that the copper is in the +II oxidation state with trigonal bipyramidal geometry and exists in a linear polymeric structure due to strong hydrogen bonding. [source] Thermally latent synthesis of networked polymers from multifunctional hemiacetal ester and diepoxide catalyzed by Schiff-base-zinc chloride complexJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 11 2008Hiroyuki Komatsu Abstract Thermally latent reaction of a copolymer (P1) bearing hemiacetal ester and n -butyl methacrylate moieties and glycidyl phenyl ether (2) was catalyzed by bis(p -methoxybenzylidene)-1,2-diiminoethane/zinc chloride complex (ZnCl2/3) at 30,150 °C for 6 h. No reaction of P1 and 2 took place below 70 °C, and it smoothly proceeded above 120 °C. The latencies and activities mean that ZnCl2/3 meets both the high latencies at ambient conditions and the high activities at desired temperatures. Thermal crosslinking reaction employing multifunctional derivatives was carried out using ZnCl2/3 at 140 °C for 6 h to afford a networked polymer in high yields. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3682,3689, 2008 [source] Highly Active, Well-Defined (Cyclopentadiene)(N-heterocyclic carbene)palladium Chloride Complexes for Room-Temperature Suzuki,Miyaura and Buchwald,Hartwig Cross-Coupling Reactions of Aryl Chlorides and Deboronation Homocoupling of Arylboronic AcidsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2009Zhong Jin Abstract A new class of well-defined N-heterocyclic carbene (NHC)-(cyclopentadiene)palladium chloride complexes such as CpPd(NHC)Cl wasw synthesized from the readily available starting NHC-palladium(II) chloride dimers. These air-stable, coordinatively saturated NHC-Pd complexes bearing the cyclopentadiene (Cp) unit exhibit high catalytic activity in the room temperature Suzuki,Miyaura and Buchwald,Hartwig cross-coupling reactions involving unactive aryl chlorides as the substrates. In addition, they are found to be extremely efficient catalysts in the deboronation homocoupling of arylboronic acids at room temperature. [source] Cationic Ruthenium-Cyclopentadienyl-Diphosphine Complexes as Catalysts for the Allylation of Phenols with Allyl Alcohol; Relation between Structure and Catalytic Performance in O - vs.ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2009C -Allylation Abstract A new catalytic method has been investigated to obtain either O - or C -allylated phenolic products using allyl alcohol or diallyl ether as the allyl donor. With the use of new cationic ruthenium(II) complexes as catalyst, both reactions can be performed with good selectivity. Active cationic Ru(II) complexes, having cyclopentadienyl and bidentate phosphine ligands are generated from the corresponding Ru(II) chloride complexes with a silver salt. The structures of three novel (diphosphine)Ru(II)CpCl catalyst precursor complexes are reported. It appears that the structure of the bidentate ligand has a major influence on catalytic activity as well as chemoselectivity. In addition, a strong cocatalytic effect of small amounts of acid is revealed. Model experiments are described that have been used to build a reaction network that explains the origin and evolution in time of both O -allylated and C -allylated phenolic products. Some mechanistic implications of the observed structure vs. performance relation of the [(diphosphine)RuCp]+ complexes and the cocatalytic role of added protons are discussed. [source] Structural correlations for 1H, 13C and 15N NMR coordination shifts in Au(III), Pd(II) and Pt(II) chloride complexes with lutidines and collidineMAGNETIC RESONANCE IN CHEMISTRY, Issue 6 2010Leszek Pazderski Abstract 1H, 13C and 15N NMR studies of gold(III), palladium(II) and platinum(II) chloride complexes with dimethylpyridines (lutidines: 2,3-lutidine, 2,3lut; 2,4-lutidine, 2,4lut; 3,5-lutidine, 3,5lut; 2,6-lutidine, 2,6lut) and 2,4,6-trimethylpyridine (2,4,6-collidine, 2,4,6col) having general formulae [AuLCl3], trans -[PdL2Cl2] and trans -/cis- [PtL2Cl2] were performed and the respective chemical shifts (,1H, ,13C, ,15N) reported. The deshielding of protons and carbons, as well as the shielding of nitrogens was observed. The 1H, 13C and 15N NMR coordination shifts (,1Hcoord, ,13Ccoord, ,15Ncoord; ,coord = ,complex , ,ligand) were discussed in relation to some structural features of the title complexes, such as the type of the central atom [Au(III), Pd(II), Pt(II)], geometry (trans - or cis -), metal-nitrogen bond lengths and the position of both methyl groups in the pyridine ring system. Copyright © 2010 John Wiley & Sons, Ltd. [source] Chemical Composition of Rock-Forming Minerals in Copper,Gold-Bearing Tonalite Porphyries at the Batu Hijau Deposit, Sumbawa Island, Indonesia: Implications for Crystallization Conditions and Fluorine,Chlorine FugacityRESOURCE GEOLOGY, Issue 2 2007Arifudin Idrus Abstract Copper,gold mineralization at the world-class Batu Hijau porphyry deposit, Sumbawa Island, Indonesia, is closely related to the emplacement of multiple stages of tonalite porphyries. Petrographic examination indicates that at least two texturally distinct types of tonalite porphyries are currently recognized in the deposit, which are designated as "intermediate tonalite" and "young tonalite". They are mineralogically identical, consisting of phenocrysts of plagioclase, hornblende, quartz, biotite and magnetite ± ilmenite, which are set in a medium-coarse grained groundmass of plagioclase and quartz. The chemical composition of the rock-forming minerals, including plagioclase, hornblende, biotite, magnetite and ilmenite in the tonalite porphyries was systematically analyzed by electron microprobe. The chemical data of these minerals were used to constrain the crystallization conditions and fluorine,chlorine fugacity of the corresponding tonalitic magma during its emplacement and crystallization. The crystallization conditions, including temperature (T), pressure (P) and oxygen fugacity (fO2), were calculated by applying the hornblende,plagioclase and magnetite,ilmenite thermometers and the Al-in-hornblende barometer. The thermobarometric data indicate that the tonalite porphyries were emplaced at 764 ± 22°C and 1.5 ± 0.3 × 105 kPa. If the pressure is assumed to be lithostatic, it is interpreted that the rim of hornblende and plagioclase phenocrysts crystallized at depths of approximately 5.5 km. As estimated from magnetite,ilmenite thermometry, the subsolidus conditions of the tonalite intrusion occurred at temperatures of 540,590°C and log fO2 ranging from ,20 to ,15 (between Ni-NiO and hematite,magnetite buffers). This occurred at relatively high fO2 (oxidizing) condition. The fluorine,chlorine fugacity in the magma during crystallization was determined on the basis of the chemical composition of magmatic biotite. The calculation indicates that the fluorine,chlorine fugacity, represented by log (fH2O)/(fHF) and (fH2O)/(fHCl) in the corresponding tonalitic magma range from 4.31 to 4.63 and 3.62 to 3.79, respectively. The chlorine fugacity (HCl) to water (H2O) is relatively higher than the fluorine fugacity (HF to water), reflecting a high activity of chlorine in the tonalitic magma during crystallization. The relatively higher activity of chlorine (rather than fluorine) may indicate the significant role of chloride complexes (CuCl2, and AuCl2,) in transporting and precipitating copper and gold at the Batu Hijau deposit. [source] Bis(amido)cyclodiphosph(III)azane Complexes of Yttrium and the LanthanidesCHEMISTRY - A EUROPEAN JOURNAL, Issue 2 2009Marcus Rastätter Dr. Abstract The first cyclodiphosph(III)azane complexes of the rare-earth elements have been synthesized. Reactions of the lithium salt cis -[(tBuNP)2(tBuN)2{Li(thf)}2] with anhydrous yttrium trichloride or the heavier lanthanide trichlorides resulted in the corresponding cyclodiphosph(III)azane complexes [Li(thf)4][{(tBuNP)2(tBuN)2}LnCl2] (Ln=Y (1,a), Ho (1,b), Er (1,c)). The single-crystal X-ray structures showed that compounds 1,a,c consisted of ion pairs composed of a [Li(thf)4]+ cation and a C2v symmetric [{(tBuNP)2(tBuN)2}LnCl2], anion. By treating cis -[(tBuNP)2(tBuN)2{Li(thf)}2] with anhydrous SmCl3 in THF, the trimetallic complex [{(tBuNP)2(tBuN)2}SmCl3Li2(thf)4] (2) was obtained. The influence of the ionic radii of the lanthanides can be seen in the single-crystal X-ray structure of compound 2, which forms a six-membered Cl-Li-Cl-Li-Cl-Sm metallacycle. The ring adopts a boat conformation in which one chlorine atom and the samarium atom are displaced from the Cl2Li2 least-square plane. Heating of the metalate complexes in toluene resulted in the extrusion of lithium chloride and the formation of the neutral dimeric metal chloride complexes of the composition [(tBuNP)2(tBuN)2LnCl(thf)]2 (Ln=Y (3,a), La (3,b) Nd (3,c), Sm (3,d)). Furthermore, treating 1,a with KNPh2 resulted in a lithium metalate complex of the composition [Li(thf)4][{(tBuNP)2(tBuN)2}Y(NPh2)2] (4). The coordination mode of the {(tBuNP)2(tBuN)2}2, ligand in 4 is different to that observed in 1,a,c, 2, and 3,a,d; instead of a symmetric ,2 coordination of the ligand, a heterocubane-type structure is observed in the solid state. The complex [(tBuNP)2(tBuN)2NdCl(thf)] (3,c) was used as a Ziegler,Natta catalyst for the polymerization of 1,3-butadiene to poly- cis -1,4-butadiene. The observed activities of the Ziegler,Natta catalyst strongly depended upon the nature of the cocatalyst; in some case very high turnover rates and a cis selectivity of 93,94,% were observed. [source] | ||||||||||