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CuI
Terms modified by CuI Selected AbstractsParticle size of powders under hydrothermal conditionsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2003Wen-Jun Li Abstract Various non-oxide (CuI, AgI, AgCl, PbS, CuS and ZnS) and oxide (ZnO, TiO2, SnO2, CeO2 and ZrO2) powders were prepared under hydrothermal conditions to investigate the effects of temperature, pH and precursors on the particle size of powders. It was found that the particle sizes of PbS, CuS and ZnS powders were much smaller than that of CuI, AgI and AgCl powders prepared under the same conditions. The particle sizes of TiO2, SnO2, CeO2 and ZrO2 powders are much smaller than that of ZnO powders prepared under the same conditions. It is concluded that the solution conditions have a certain effect on the particle size of powders under the hydrothermal conditions. The particle size of powders increased with the rising of temperature. Additional factors affecting the particle size were uncovered through studying the nucleation mechanism. The particle size was mainly related to the Madelung constant and the electric charge number of ions. Powders with smaller particle size resulted from systems that possessed the larger Madelung constant and ionic charge number. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Copper-Azide-Thioarylazoimidazoles , Structure, Spectra, Redox Properties, Magnetism and Theoretical InterpretationEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 2 2010Prasenjit Bhunia Abstract Azido-copper(II) and -copper(I) complexes of 1-alkyl-2-[(o -thioalkyl)phenylazo]imidazole (SRaaiNR,) have been prepared and studied. Complex 2 [Cu(SRaaiNR,)(,1,1 -N3)(N3)]2 dimerises via end-to-end (,1,3)-N3 to form a tetrameric structure. Azido-copper(I) complexes of the ligands are obtained as MeOH-bridged dimers, [Cu(SRaaiNR,)(N3)(,-OHMe)]2 (3). The electronic spectra suggest that a small reorganisation energy (0.08 eV) is associated with the change in electronic configuration, structure and oxidation state from CuII to CuI. Redox interconversion, CuII , CuI, [Cu(SMeaaiNMe)(,-N3)(N3)]2 (2a) , [Cu(SMeaaiNMe)(N3)(,-OHCH3)]2 (3a), has been performed in one case. The tetranuclear complex shows ferromagnetic and antiferromagnetic interactions. The spectra, redox chemistry and magnetism are explained by DFT studies. [source] Copper Complexes with Neutral N4 Tripodal Ligands: Influence of the Number of Nitrogen Donors on Their Structures, Properties, and Reactivity,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 26 2009Kiyoshi Fujisawa Abstract Copper coordination complexes of the neutral tetradentate nitrogen-containing ligands tris(3,5-dimethylpyrazol-1-ylmethyl)amine (L0N4) and tris(3,5-diisopropylpyrazol-1-ylmethyl)amine (L1N4), namely the copper(II) chlorido complexes [CuII(L0N4)Cl2] (1) and [CuII(L1N4)Cl2] (2), the copper(II) nitrato complexes [CuII(L0N4)(NO3)](NO3) (3) and [CuII(L1N4)(NO3)](NO3) (4), and the copper(II) sulfato complexes [CuII(L0N4)(SO4)] (5) and [CuII(L1N4)(SO4)] (6), and the copper(I) complexes [CuI(L0N4)](PF6) (7) and [CuI(L0N4)(PPh3)](ClO4) (8), have been systematically synthesized in order to investigate the influence of the number of nitrogen donors on their structures, properties, and reactivity. All copper(II) complexes were fully characterized by X-ray crystallography and by IR/far-IR, UV/Vis absorption, and ESR spectroscopy. Although the structure of 7 was not determined by X-ray crystallography, this complex and the structurally characterized copper(I) triphenylphosphane complex 8 were fully characterized by IR/far-IR and NMR spectroscopy. A comparison of the copper(II) complexes with two tris(pyrazol-1-ylmethyl)amine ligands with different bulkiness of the pyrazolyl rings has allowed us to evaluate the second coordination sphere effects of the ligands. Moreover, the structures and physicochemical properties of these complexes are compared with those of related complexes containing the neutral tridentate tris(pyrazolyl)methane ligand and the neutral bidentate bis(pyrazolyl)methane ligand. Finally, the relative stability of the copper(I) complexes is discussed. The influence of the number of nitrogen donors in copper complexes is observed from these systematic results.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] The Variable Binding Modes of Phenylbis(pyrid-2-ylmethyl)phosphane and Bis(pyrid-2-ylmethyl) Phenylphosphonite with AgI and CuIEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 20 2009Fernando Hung-Low Abstract A series of new bridging phosphane and phosphonite structures forming three- and six-membered rings with the metal centers were synthesized and characterized. The resulting compounds of phenylbis(pyrid-2-ylmethyl)phosphane (1) with the silver(I) salts of trifluoroacetate (tfa,), tetrafluoroborate (BF4,), and trifluoromethanesulfonate (OTf,), and copper tetrakis(acetonitrile) hexafluorophosphate (PF6,) shows the flexibility of the ligand by displaying different coordination modes associated with the electronic and structural characteristics of the corresponding anion. Accordingly, ligand 1 in these complexes displays two different binding modes. With Agtfa and AgBF4 compounds 3 and 4 are obtained where the ligand chelates to two silver atoms that exhibit normalAg,Ag contacts in the range of 2.9 Å. When AgOTf or Cu(NCCH3)4PF6 are used, one molecule of 1 bridges the metal centers through a phosphorus atom while another is terminally bound. This induces short M,M distances of 2.6871 and 2.568 Å for 5 and 6, respectively. Similarly, the coordination behavior of the heterofunctional bis(pyrid-2-ylmethyl) phenylphosphonite ligand (2) is reported with Cu(NCCH3)4PF6 (7) and AgBF4 (8) to form two novel discrete molecules. In these complexes 2 coordinates through the P and N atoms, with the difference that in 7 the O atom of one of the carbinol arms is also bound to the Cu. Elemental analysis, variable-temperature multinuclear NMR spectroscopy, single-crystal X-ray diffraction, and low-temperature luminescence studies were carried out to fully characterize the compounds. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Checking the Route to Cluster HelicatesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 24 2008Manuel R. Bermejo Abstract The aim of the work described here was to test the general applicability of our recently reported route to cluster helicates and to carry out a systematic study to relate the structural and coordinative properties of the organic strands with the microarchitectures of the resulting cluster helicates. Nine new ZnII, CuI and AgI complexes were prepared from three Schiff base ligands [H2La: bis(4-methyl-3-thiosemicarbazone)-2,6-diacetylpyridine; H2Lb: bis(4-methyl-3-thiosemicarbazone)-2,6-diacetylbenzene; H2Lc: bis(4-ethyl-3-thiosemicarbazone)-2,6-diacetylbenzene]. The experimental data confirm that AgI and CuI tetranuclear cluster helicates were obtained with a [M4(Lx)2] stoichiometry, and this finding demonstrates the general applicability of the synthetic route. The cluster helicates presented in this work were characterized for the first time in solution by NMR spectroscopy. In addition, six of the nine complexes were characterized by X-ray diffraction studies, and three of them were found to be tetranuclear cluster helicates. A detailed study of these three crystal structures leads us to state that the changes introduced in the organic strands do not prevent the assembly of the tetranuclear cluster dihelicates, but they do affect the microarchitectures. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Construction of 1D and 2D Copper(I) Coordination Polymers Assembled by PhS(CH2)nSPh (n = 1, 2) Dithioether Ligands: Surprising Effect of the Spacer Length on the Dimensionality, Cluster Nuclearity and the Fluorescence Properties of the Metal,Organic Framework,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2007Harmel N. Peindy Abstract Treatment of CuI with PhSCH2SPh in MeCN solution affords, by a self-assembly reaction, the monodimensional metal,organic coordination polymer [Cu4I4{,-PhS2CH2SPh}2]n (1), in which Cu4(,3 -I)4 cluster units are linked by the dithioether ligand in a 1D necklace structure. In contrast, the reaction of PhSCH2CH2SPh with CuI results in the formation of the metallopolymer [(CuI)2{,-PhS(CH2)2SPh}2]n (2). The 2D network of 2 is built from dimeric Cu2I2 units which are connected by 1,2-bis(phenylthio)ethane bridging ligands. The solid-state luminescence spectrum of 1 exhibits a strong emission around 532 nm, whereas a weak emission centred at 413 nm is observed in the case of 2. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Synthesis, Structure and Spectroscopic Properties of Novel9,10-Bis{[6-(diphenylphosphanyl)-2-pyridylmethyl]propylaminomethyl}anthracene-Bridged Group 11 Metal (M = CuI and AgI) Dinuclear ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2005Hu Xu Abstract Dinuclear complexes [M2(,-BPNNAn)]X2 (M = CuI, X = ClO4,1, X = BF4,2; M = AgI, X = BF4,3, X = ClO4,4) have been prepared by treating 9,10-bis{[6-(diphenylphosphanyl)-2-pyridylmethyl]propylaminomethyl}anthracene (BPNNAn) with M(CH3CN)4X in CH2Cl2. The structures of complexes 1, 2 and 3 have been determined by single-crystal X-ray diffraction studies. In the complexes, BPNNAn acts as a chelating ligand and two metal ions riding on two bridgehead carbon atoms in the anthracene group leads to the deformation of the anthracenyl ring. The Cu,Arene charge transfer interaction is observed from the nonfluorescent emission of Cu complex 1, while the Ag complex 3 exhibits dual emission at high concentrations in a CH2Cl2 solution. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] [CuI(im)],: Is this Air-Stable Copper(I) Imidazolate (8210)-Net Polymer the Species Responsible for the Corrosion-Inhibiting Properties of Imidazole with Copper Metal?EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 9 2004Yun-Qi Tian Abstract An air-stable two-dimensional (2D) copper(I) imidazolate polymer, [CuI(im)], (1), with a d10 -d10 interaction, was synthesized solvothermally and structurally characterized by X-ray crystallography: a = 8.069(2), b = 8.068(2), c = 13.425(3) Å, , = 99.414(3)°, monoclinic, C2/c. This is the first example of an air-stable copper(I) imidazolate polymer that may play a significant role in the corrosion-inhibition mechanism of imidazole (or its derivatives) with copper metal. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Copper(I)-Assembled Pseudorotaxanes Bearing Bis(nitrile) Ligands: Selective Formation of Large Chelate RingsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 3 2004Efstathia G. Sakellariou Abstract The syntheses of two novel CuI -bis(benzonitrile) complexes of the type [Cu(dCNn)2][PF6] {where dCNn = NCPhO(CH2)nOPhCN, n = 3, 4} are described. Both compounds have been characterized by X-ray crystallography. To our surprise, and although the two complexes were quite similar, two very distinct structures were obtained. For the [Cu(dCN4)2][PF6] complex, a tetrahedral geometry was observed whereas for [Cu(dCN3)2][PF6], a polymeric assembly was formed. A further extension of this work involved the syntheses of two threaded species bearing the M30 macrocycle, Cu metal and a dCNn ligand. The formation of the desired complexes was confirmed by means of mass spectrometry as well as 1-D and 2-D 1H NMR spectroscopy. Finally, the cyclic voltammograms of all 4 new species were recorded giving rise to redox potentials ranging from +0.88 to +1.25 V. These new threaded complexes are of particular interest since they can form the basis of novel rotaxane structures. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Extended X-ray Absorption Fine Structure Study of Copper(I) and Copper(II) Complexes in Atom Transfer Radical PolymerizationEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 11 2003Tomislav Pintauer Abstract Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy has been used to investigate structural features of CuIBr and CuIIBr2 complexes with dNbpy, PMDETA, Me6TREN, tNtpy, and Me4CYCLAM in various solvents {dNbpy = 4,4,-bis(5-nonyl)-2,2,-bipyridine, PMDETA = N,N,N,,N,,,N,, -pentamethyldiethylenetriamine, Me6TREN = tris[2-(dimethylamino)ethyl]amine, tNtpy = 4,4,,4,,-tris(5-nonyl)-2,2,:6,,2,,-terpyridine, Me4CYCLAM = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane}. The structures of the CuI and CuII complexes were found to depend on the solvent polarity and the number of nitrogen atoms in the ligand. Generally, in non-polar media and with monomers typically used in ATRP, CuI complexes preferred a tetracoordinate geometry, and were either ionic as observed in [CuI(dNbpy)2]+[CuIBr2], (CuI,NAV = 2.00 Å, CuI,BrAV = 2.25 Å) and [CuI(Me4CYCLAM)]+[CuIBr2], (CuI,NAV = 2.06 Å, CuI,BrAV = 2.23 Å), or neutral as in [CuI(PMDETA)Br] (CuI,NAV = 2.12 Å, CuI,BrAV = 2.33 Å), and [CuI(tNtpy)Br] (CuI,NAV = 2.03 Å, CuI,BrAV = 2.29 Å). The EXAFS analysis of CuIIBr2 complexes indicated a preference for a coordination number of five, such as in [CuII(dNbpy)2Br]+[Br], (CuII,NAV = 2.03 Å, CuII,BrAV = 2.43 Å), [CuII(PMDETA)Br2] (CuII,NAV = 2.03 Å, CuII,Br1,AV = 2.44 Å, CuII,Br2,AV = 2.64 Å) and [CuII(Me6TREN)Br]+[Br], (CuII,NAV = 2.09 Å, CuII -BrAV = 2.39 Å), with the exception of the neutral tetracoordinate [CuII(dNbpy)Br2] (CuII,NAV = 2.02 Å, CuII,BrAV = 2.36 Å), which has been observed in non-polar media. Additionally, polar media were found to favor bromide dissociation in [CuII(Me6TREN)Br]+[Br], and [CuII(PMDETA)Br2], as indicated by a decrease in the Br and Cu coordination numbers at the Cu- and Br- K -edges, respectively. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Syntheses and Crystal Structures of Copper and Silver Complexes with New Imine Ligands , Air-Stable, Photoluminescent CuIN4 ChromophoresEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 5 2003Goutam Kumar Patra Abstract A series of new imine ligands [1 (C12H12N2S2), 2 (C12H12N2S2), 3 (C24H18N4S2), and 5 (C30H27N7)] have been synthesized (1 and 2 are structural isomers). CuI and AgI complexes of the nonconjugated dithiophene-diimine ligands 1, 2 and the tripodal imine-amine ligand 5 have also been prepared and thoroughly characterized by spectroscopic techniques as well as by X-ray diffraction. In cyclic voltammetry at a glassy carbon milli electrode in anhydrous dichloromethane under dry N2, the corresponding CuI complexes [6 (2C12H12N2S2·CuClO4), 7 (2C12H12N2S2·CuClO4), and 12 (C30H27N7·CuClO4)] show quasi-reversible CuII/I couples with high redox potentials (1.001 V for 6, 0.958 V for 7, and 0.692 V for 12, vs. Ag/AgCl). This indicates that the ,-acid ligands 1, 2, and 5 preferentially stabilize copper(I) over copper(II). The CuIN4 chromophores in the complexes 6, 7, and 12 display photoluminescence in dichloromethane at room temperature. The related silver complexes of the same three ligands 10 (2C12H12N2S2·AgClO4), 11 (2C12H12N2S2·AgClO4), and 13 [C30H27N7·Ag(CH3CN)ClO4] reveal similar structural features but lack specific photophysical properties. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] CuI -Catalyzed Azide,Alkyne Intramolecular i -to-(i+4) Side-Chain-to-Side-Chain Cyclization Promotes the Formation of Helix-Like Secondary StructuresEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 3 2010Mario Scrima Abstract A solid-phase assembly of model peptides derived from human parathyroid hormone-related protein (11,19) containing ,-azido- and ,-yl-,-amino acid residues in positions i and i+4 was cyclised in solution by an intramolecular CuI -catalyzed azide,alkyne 1,3-dipolar Huisgen cycloaddition. These series of heterodetic cyclo-nonapeptides varied in the size of the disubstituted 1,2,3-triazolyl-containing bridge, the location and the orientation of the 1,2,3-triazolyl moiety within the bridge. The 1,2,3-triazolyl moiety, presented at either 1,4- or 4,1-orientation, is flanked by side chains containing 1,4 CH2 groups that result in bridges comprised from 4,7 CH2 groups connecting residues 13 and 17. Comprehensive conformational analysis employing CD, NMR and molecular dynamics reveals the conformational propensities of these heterodetic cyclo-nonapeptides. Cyclo-nonapeptides containing either the 7 methylene bridge (VII and VIII) or the 4 methylene bridge (II) are unstructured in structure-promoting solvent. Cyclo-nonapeptide I in which the 1,4-disubstituted 1,2,3-triazolyl is flanked by 3 and 1 CH2 groups in proximity to the respective residues 13 and 17, is stabilized in a non-canonical structure. All the other heterodetic cyclo-nonapeptides (III,VI) in which the 1,2,3-triazolyl is flanked by a total of 5 or 6 CH2 groups nicely accommodate ,-helical structures and reproduce very closely the helical structure stabilized by the analogous cyclo-nonapeptide in which Lys13 and Asp17 are bridged by the isosteric lactam. These studies suggest that the bioorthogonal i -to-(i+4) side-chain-to-side-chain cyclization via the prototypic "click reaction" offers a new and powerful approach for generating stable helix mimetic structures. [source] Synthesis of Triazole-Bridged Unsymmetrical Porphyrin Dyads and Porphyrin,Ferrocene ConjugatesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 3 2010Vijayendra S. Shetti Abstract A simple method has been used to synthesize four porphyrin azides with cores such as N4, N3S, N2SO and N2S2 in 60,90,% yields by treating the corresponding aminoporphyrins with tert -butyl nitrite (tBuONO) and azidotrimethylsilane (TMSN3) in THF/CH3CN under mild reaction conditions. The hitherto unknown aminoporphyrins with heteroatom cores were synthesized from their corresponding nitroporphyrins by standard SnCl2/HCl reduction. The azidoporphyrins were used to synthesize six triazole-bridged unsymmetrical porphyrin dyads containing two different types of porphyrin sub-units as well as five triazole-bridged porphyrin,ferrocene conjugates under CuI -catalyzed "click" reaction conditions. Various CuI -catalyzed reaction conditions were studied and the best yields of triazole-bridged dyads and conjugates were obtained with CuI/DIPEA in THF/CH3CN at room temperature for overnight. The unsymmetrical porphyrin dyads and porphyrin,ferrocene conjugates were characterized by various spectroscopic and electrochemical techniques. In unsymmetrical porphyrin dyads, the NMR, absorption and electrochemical studies indicate a weak interaction between the two porphyrin sub-units. However, preliminary photophysical studies support an efficient singlet-singlet energy transfer from one porphyrin unit to another in five unsymmetrical dyads reported here. In porphyrin,ferrocene conjugates, the fluorescence of porphyrin was quenched significantly due to photo-induced electron transfer from ferrocene to porphyrin. [source] Preparation of Fused Tetracyclic Quinazolinones by Combinations of Aza-Wittig Methodologies and CuI -Catalysed Heteroarylation ProcessesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 15 2009Juan Antonio Bleda Abstract A number of linear quinazolinones fused to five-membered rings , benzimidazo[2,1- b]quinazolinones 8 and benzothiazolo[2,3- b]quinazolinones 10 , have been prepared from iminophosphoranes 4, derived from N -substituted o -azidobenzamides by a combination of the aza-Wittig methodology and CuI -catalysed heteroarylation. The presence of a nitrogen functionality in the N -aryl substituent of 4 promotes heterocyclization after an aza-Wittig reaction/reductive process, either across the 2-position, to afford quinazolino[2,1- b]quinazolinones 11,14, or across the 4-position, to afford the benzimidazo[1,2- c]quinazoline 16 from the initially formed 3H -quinazolin-4-one. When an acetyl group is present in the N -aryl substituent of 4, aza-Wittig reactions with isocyanates lead directly to 4-methylene-4H -3,1-benzoxazines 18; this transformation involves the initial formation of a carbodiimide, which undergoes ring-closure through the enol form of the carboxamide group and eventually an unprecedented iminobenzoxazine/methylenebenzoxazine rearrangement. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Silica-Immobilized NHC,CuI Complex: An Efficient and Reusable Catalyst for A3 -Coupling (Aldehyde,Alkyne,Amine) under Solventless Reaction ConditionsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 13 2008Min Wang Abstract A novel silica-immobilized NHC,CuI complex was developed and used as a highly efficient catalyst in the three-component coupling reactions of aldehydes, alkynes and amines (A3 -coupling). The reactions were applicable to aromatic and aliphatic aldehydes, alkynes and amines, and generated the corresponding propargylamines in good yields only in the presence of SiO2,NHC,CuI (2 mol-%) at room temp. under solvent-free reaction conditions. Moreover, the catalyst was quantitatively recovered from the reaction mixture by a simple filtration and reused for ten cycles with almost consistent activity.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Efficient Copper(I)-Catalyzed C,S Cross Coupling of Thiols with Aryl Halides in WaterEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 4 2008Laxmidhar Rout Abstract CuI efficiently catalyzes the C,S cross coupling of thiols with aryl halides in the presence of tetrabutylammonium bromide in water. The reactions with aryl thiols that have electron-withdrawing and -donating substituents are comparable and afford C,S cross-coupling products in high yield. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] CuI/DABCO-Catalyzed Cross-Coupling Reactions of Aryl Halides with Arylboronic AcidsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 9 2006Jin-Heng Li Abstract CuI combined with DABCO (1,4-diaza-bicyclo[2.2.2]octane) was developed as an inexpensive and efficient catalytic system for the Suzuki,Miyaura cross-coupling of aryl halides with arylboronic acids. The couplings between aryl iodides and arylboronic acids catalyzed by catalytic amounts of CuI and DABCO proceeded smoothly in moderate to excellent yields. However, the CuI/DABCO system was less efficient in the reactions of aryl bromides, and a higher reaction temperature was required to improve the yield. For the less activated aryl bromides, a stoichiometric amount of CuI together with TBAB was necessary to obtain satisfactory yields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [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] p,n-Junction-Based Flexible Dye-Sensitized Solar CellsADVANCED FUNCTIONAL MATERIALS, Issue 2 2010Liping Heng Abstract In this paper, a new type of flexible working electrode, TiO2/CuI/Cu, is reported, in which the p,n junction of TiO2,CuI is introduced into dye-sensitized solar cells (DSSCs) for the first time. The devices give a high conversion efficiency of up to 4.73% under 1 sun illumination. The excellent performance is ascribed to the existence of the p,n junction, which forms a single directional pathway for electron transport which benefits the charge separation, and improves the efficiency of the flexible solar cells as a result. [source] 2-Azido-2-deoxycellulose: Synthesis and 1,3-Dipolar CycloadditionHELVETICA CHIMICA ACTA, Issue 4 2008Fuyi Zhang Abstract Chitosan (1) was prepared by basic hydrolysis of chitin of an average molecular weight of 70000 Da, 1H-NMR spectra indicating almost complete deacetylation. N -Phthaloylation of 1 yielded the known N -phthaloylchitosan (2), which was tritylated to provide 3a and methoxytritylated to 3b. Dephthaloylation of 3a with NH2NH2,H2O gave the 6- O -tritylated chitosan 4a. Similarly, 3b gave the 6- O -methoxytritylated 4b. CuSO4 -Catalyzed diazo transfer to 4a yielded 95% of the azide 5a, and uncatalyzed diazo transfer to 4b gave 82% of azide 5b. Further treatment of 5a with CuSO4 produced 2-azido-2-deoxycellulose (7). Demethoxytritylation of 5b in HCOOH gave 2-azido-2-deoxy-3,6-di- O -formylcellulose (6), which was deformylated to 7. The 1,3-dipolar cycloaddition of 7 to a range of phenyl-, (phenyl)alkyl-, and alkyl-monosubstituted alkynes in DMSO in the presence of CuI gave the 1,2,3-triazoles 8,15 in high yields. [source] Copper-Binding Motifs: Structural and Theoretical AspectsHELVETICA CHIMICA ACTA, Issue 5 2003Amy Kaufman, Katz In this paper, we report the results of a study involving the coordination geometries of CuI, CuII, and CuIII crystal structures in the Cambridge Structural Database, and on Cu binding sites in proteins taken from the Protein Data Bank. The motifs used to bind two bridged Cu ions are also described. In addition, we report the results of ab initio molecular-orbital calculations performed on a variety of model CuI/CuII complexes (CuI/CuII,XnYm (X, Y=NH3, SH2); n+m=4; n=0,4) to provide data on the structural and energetic changes that occur in isolated complexes when the oxidation state of the Cu ion is changed from II to I while the coordination number is conserved. The use of such simple ligands in these calculations eliminates constraints on the geometric changes that may be imposed by more-complicated ligands. [source] Efficient Synthesis of 2-Fluoromethylated Quinolines via Copper-Catalyzed Alkynylation and Cyclization of Fluorinated Imidoyl IodidesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2010Shan Li Abstract 2-Fluoromethylated quinolines were synthesized through the reaction of N -aryl-fluorinated imidoyl iodides with terminal alkynes in good yields by the catalysis of copper(I) iodide (CuI) alone. [source] Copper-catalyzed phosphinidene transfer to ethylene, acetylene, and carbon monoxide: A computational studyINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 9 2010Matthew J. Amme Abstract A DFT study of phosphinidene transfer by copper model catalysts is reported. PR-transfer pathways are highly exergonic with respect to catalyst and phosphinidene transfer reagent. Calculated free energy barriers by which (dhpe)Cu(PMe) active species yields functionalized products are reasonable for modeled substrates,ethylene, acetylene, and carbon monoxide. Calculations suggest a (dhpe)CuI(-PMe·,) formulation as more appropriate than (dhpe)CuII(=PMe2,). The preferred pathway for production of phosphirane (phosphirene) is via direct [1 + 2] addition of ethylene (acetylene) to the PMe group of (dhpe)Cu(PMe), which contrasts the [2 + 2] mechanism for the reaction of ethylene with Ni0 -phosphinidenes. In light of simulations for neutral and cationic models, it is concluded that the extra electron in copper destabilizes [2 + 2] pathways. Calculated energetics for (dhpe)Cu(PMe) versus (en)Cu(PMe), dhpe = 1,2- bis(dihydrophosphino)ethane, en = ethylenediamine, indicate that the former is a more potent for PR-transfer. Thus, it is inferred that modifications that result in a more electron deficient metal center will yield better group transfer catalysts. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 [source] Conventional Tetrakis(triphenylphosphine)palladium-Copper(I) Iodide-Catalyzed Sonogashira Coupling of Free and BOC- Protected Propargylic Amines "On Water"ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Bartomeu Soberats Abstract Alkynylation of aryl iodides with propargylic amines has been achieved by means of a Sonogashira coupling using "on water" methods. The use of less than 0.2,mol% of tetrakis(triphenylphosphine)palladium [Pd(PPh3)4] and 1.5,mol% copper(I) iodide [CuI] in the presence of diisopropylethylamine (DIPEA) allows the coupling to proceed at 95,°C yielding moderate to good yields of mono-, bis-, and tris-aminoalkynylbenzene derivatives. [source] Highly Convenient, Clean, Fast, and Reliable Sonogashira Coupling Reactions Promoted by Aminophosphine-Based Pincer Complexes of Palladium Performed under Additive- and Amine-Free Reaction ConditionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6 2009Jeanne Abstract Sequential addition of 1,1,,1,,-phosphinetriyltripiperidine and 1,3-diaminobenzene or resorcinol to toluene solutions of (cyclooctadiene)palladium dichloride [Pd(cod)(Cl)2] under nitrogen in "one pot" almost quantitatively yielded the aminophosphine-based pincer complexes {[C6H3 -2,6-(XP{piperidinyl}2)2]Pd(Cl)} (X=NH 1; X=O 2). Complex 1 (and to a minor extent 2) proved to be efficient Sonogashira catalysts, which allow the quantitative coupling of various electronically deactivated and/or sterically hindered and functionalized aryl iodides and aryl bromides with several alkynes as coupling partners within very short reaction times and low catalyst loadings. Importantly, in contrast to most of the Sonogashira catalysts, which either are both air- and moisture-sensitive and/or require the addition of co-catalysts, such as copper(I) iodide [CuI], for example, or a large excess of an amine, the coupling reactions were carried out without the use of amines, co-catalysts or other aditives and without exclusion of air and moisture. Moreover, the desired products were exclusively formed (no side-products were detected) without employing an excess of one of the substrates. Ethylene glycol and potassium phosphate (K3PO4) were found to be the ideal solvent and base for this transformation. Experimental observations strongly indicate that palladium nanoparticles are not the catalytically active form of 1 and 2. On the other hand, their transformation into another homogeneous catalytically active species cannot be excluded. [source] An Inexpensive and Efficient Copper Catalyst for N -Arylation of Amines, Amides and Nitrogen-Containing HeterocyclesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 15 2006Xun Guo Abstract An inexpensive and efficient catalyst system has been developed for the N -arylation of nitrogen-containing compounds including a variety of amines, amides, indole and imidazole. This simple protocol uses CuI as the catalyst, commercial available pipecolinic acid as the new ligand, K2CO3 as the base and DMF as the solvent. [source] A Convenient High Activity Catalyst for the Sonogashira Coupling of Aryl BromidesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2005Axel Köllhofer Abstract A mixture of Na2PdCl4, CuI and (t -Bu)3PH+BF4, (molar ratio 4,:,3,:,8) dispersed in H2N(i -Pr)2+Br, can be used as a "single source" precatalyst for the Sonogashira coupling of aryl bromides with various aryl- and alkylacetylenes in HN(i -Pr)2 solvent. Arylacetylenes require just 0.005,mol,% of Pd catalyst at 80,°C, with TOFs ranging between 3,200 and 10,000,h,1. [source] Room-temperature RAFT copolymerization of 2-chloroallyl azide with methyl acrylate and versatile applications of the azide copolymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2010Guang Li Abstract A new vinyl azide monomer, 2-chlorallyl azide (CAA), has been synthesized from commercially available reagent in one step. The reversible addition fragmentation chain transfer (RAFT) copolymerization of CAA with methyl acrylate (MA) was carried out at room temperature using a redox initiator, benzoyl peroxide (BPO)/N,N -dimethylaniline (DMA), in the presence of benzyl 1H -imidazole-1-carbodithioate (BICDT). The polymerization results showed that the process bears the characteristics of controlled/living radical polymerizations, such as the molecular weight increasing linearly with the monomer conversion, the molecular weight distribution being narrow, and a linear relationship existing between ln([M]0/[M]) and the polymerization time. Chain extension polymerization was performed successfully to prepare block copolymer. Furthermore, the azide copolymers were functionalized by CuI -catalyzed "click" reaction with alkyne-containing poly(ethylene glycol) (PEG) to yield graft copolymers with hydrophilic PEG side chains. Surface modification of the glass sheet was successfully achieved via the crosslinking reaction of the azide copolymer under UV irradiation at ambient temperature. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1348,1356, 2010 [source] Living radical polymerization of vinyl chloride initiated with iodoform and catalyzed by nascent Cu0/tris(2-aminoethyl)amine or polyethyleneimine in water at 25 °C proceeds by a new competing pathways mechanismJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2003Virgil Percec Abstract The first example of living radical polymerization of vinyl chloride carried out in water at 25 °C is reported. This polymerization was initiated by iodoform and catalyzed by nascent Cu0 produced by the disproportionation of CuI in the presence of strongly CuII binding ligands such as tris(2-aminoethyl)amine or polyethyleneimine. The resulting poly(vinyl chloride) was free of structural defects, had controlled molecular weight and narrow molecular weight distribution, contained two ,CHClI active chain ends, and had a higher syndiotacticity (62%) than the one obtained by conventional free-radical polymerization at the same temperature (56%). This novel polymerization proceeds, most probably, by a combination of competitive pathways that involves activation by single electron transfer mediated by nascent Cu0 and degenerative chain transfer. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3283,3299, 2003 [source] Site-selective XAFS spectroscopy tuned to surface active sites of Cu/ZnO and Cr/SiO2 catalystsJOURNAL OF SYNCHROTRON RADIATION, Issue 2 2001Yasuo Izumi XAFS (X-ray absorption fine structure) spectra were measured by using the fluorescence spectrometer for the emitted X-ray from sample. The chemical shifts between Cu0 and CuI and between CrIII and CrVI were evaluated. Tuning the fluorescence spectrometer to each energy, the Cu0 and CuI site-selective XANES for Cu/ZnO catalyst were measured. The first one was similar to the XANES of Cu metal and the second one was the 5 : 5 average of XANES for CuI sites + Cu metal. The population ratio of copper site of the Cu/ZnO catalyst was found to be Cu metal : Cu2O : CuI atomically dispersed on surface = 70(±23) : 22(±14) : 8(±5). Site-selective XANES for CrIII site of Cr/SiO2 catalyst was also studied. [source] | |||||||||||||||||||||||||||||||||||||