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101.
Applied Biochemistry and Biotechnology - The US chemical industry is facing maturing markets, variability in raw materials supply, and stiff competition from emerging chemical industries in other... 相似文献
102.
The coordination chemistries of the potential tetradentate ligands N,N'-bis(3,5-di-tert-butyl-2-hydroxyphenyl)ethylenediamine, H4[L1], the unsaturated analogue glyoxal-bis(2-hydroxy-3,5-di-tert-butylanil), H2[L2], and N,N'-bis(2-hydroxy-3,5-di-tert-butylphenyl)-2,2-dimethylpropylenediamine, H4[L3], have been investigated with nickel(II), palladium(II), and copper(II). The complexes prepared and characterized are [Ni(II)(H3L1)2] (1), [Ni(II)(HL2)2].5/8CH2Cl2 (2), [Ni(II)(L3**)] (3), [Pd(II)(L3**)][Pd(II)(H2L3) (4), and [Cu(II)(H2O)(L4)] (5), where (L4)2- is the oxidized diimine form of (L3)4- and (L3**)2- is the bis(o-iminosemiquinonate) diradical form of (L3)4-. The structures of compounds 1-5 have been determined by single crystal X-ray crystallography. In complexes 1 and 2, the ligands (H3L1)- and (HL2)- are tridentate and the nickel ions are in an octahedral ligand environment. The oxidation level of the ligands is that of an aromatic o-aminophenol. 1 and 2 are paramagnetic (mu(eff) approximately 3.2 mu(B) at 300 K), indicating an S = 1 ground state. The diamagnetic, square planar, four-coordinate complexes 3 and [Pd(II)(L3**)] in 4 each contain two antiferromagnetically coupled o-iminobenzosemiquinonate(1-) pi radicals. Diamagnetic [Pd(II)(H2L3)] in 4 forms an eclipsed dimer via four N-H.O hydrogen bonding contacts which yields a nonbonding Pd.Pd contact of 3.0846(4) A. Complex 5 contains a five-coordinate Cu(II) ion and two o-aminophenolate(1-) halves in (L4)2-. The electrochemistries of complexes 3 and 4a ([Pd(II)(L3**)] of 4) have been investigated, and the EPR spectra of the monocations and -anions are reported. 相似文献
103.
Verch A Hahn H Krause E Cölfen H Börner HG 《Chemical communications (Cambridge, England)》2010,46(47):8938-8940
Self-assembled peptide-polymer nanotapes of poly(ethylene oxide)-peptide conjugates are modified by a simple amine-azide transfer to create azide-containing nanofibres, which provide a platform for modular functionalization as demonstrated by the introduction of different carboxyl bearing entities to modulate the calcium binding properties of the nanotapes. 相似文献
104.
Martin Hoefling Francesco Iori Dr. Stefano Corni Dr. Kay‐Eberhard Gottschalk Dr. 《Chemphyschem》2010,11(8):1763-1767
The interactions of amino acids with inorganic surfaces are of interest for biologists and biotechnologists alike. However, the structural determinants of peptide–surface interactions have remained elusive, but are important for a structural understanding of the interactions of biomolecules with gold surfaces. Molecular dynamics simulations are a tool to analyze structures of amino acids on surfaces. However, such an approach is challenging due to lacking parameterization for many surfaces and the polarizability of metal surfaces. Herein, we report DFT calculations of amino acid fragments in vacuo and molecular dynamics simulations of the interaction of all amino acids with a gold(111) surface in explicit solvent, using the recently introduced polarizable gold force field GolP. We describe preferred orientations of the amino acids on the metal surface. We find that all amino acids preferably interact with the gold surface at least partially with their backbone, underlining an unfolding propensity of gold surfaces. 相似文献
105.
106.
[PdCl(C6H3(OPPri2)2-2,6)] 1 catalyses the coupling of electron-rich, electron-neutral and electron-deficient aryl chlorides with phenylacetylene in the presence of ZnCl2 as cocatalyst to give the products in modest to excellent yields. 相似文献
107.
Eberhard?ReimannEmail author Christian?Ettmayr 《Monatshefte für Chemie / Chemical Monthly》2004,135(8):959-972
Summary. N-Alkylation of certain angularly substituted heterocycles by C2- and C3-units provided appropriate precursors to construct stereoselectively the erythrinanone and several erythrinanone type analogues by intramolecular Friedel-Crafts acylation. The resulting aromatic ketones were catalytically reduced affording the corresponding parent frameworks including the hitherto unknown tetracyclus A-norschelhammerane. On the other hand, the stereoselective reduction of the carbonyl moiety offered a convenient approach to 11-hydroxylated erythrinanes with the natural occurring -configuration. The structures and the stereochemistry of the target compounds were proved by NMR spectroscopy.Part of PhD thesis, LMU München, D 相似文献
108.
Torsten C. Schmidt Melanie Less Rainer Haas Eberhard von Lw Klaus Steinbach Gottfried Stork 《Journal of chromatography. A》1998,810(1-2):161-172
A new method for the selective determination of aromatic amines is presented, which is based on the solid-phase extraction at pH 9 and subsequent derivatization of the analytes to the corresponding iodobenzenes. These can selectively and sensitively be determined with gas chromatography and electron-capture detection. Separation of at least 30 compounds in a single chromatographic run in 30 min is possible. With this method, 56 aromatic amines were investigated, and only in six cases no derivatives were obtained. Limits of quantitation were between 0.5 and 8 μg l−1, but may still be lowered with higher sample volumes or different injection techniques. The application to water samples revealed the suitability for the investigation of ground, leachate and wastewater. 相似文献
109.
Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes. XX Formation and Structure of [{η2‐tBu2P–P}Pt(PHtBu2)(PPh3)] [{η2‐tBu2P1–P2}Pt(P3Ph3)(P4Ph3)] ( 2 ) reacts with tBu2PH exchanging only the P3Ph3 group to give [{η2‐tBu2P1–P2}Pt(P3HtBu2)(P4Ph3)] ( 1 ). The crystal stucture determination of 1 together with its 31P{1H} NMR data allow for an unequivocal assignment of the coupling constants in related Pt complexes. 1 crystallizes in the triclinic space group P1 (no. 2) with a = 1030.33(15), b = 1244.46(19), c = 1604.1(3) pm, α = 86.565(17)°, β = 80.344(18)°, γ = 74.729(17)°. 相似文献
110.
Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes XXI The Influence of the PR3 Ligands on Formation and Properties of the Phosphinophosphinidene Complexes [{η2‐tBu2P–P}Pt(PR3)2] and [{η2‐tBu2P1–P2}Pt(P3R3)(P4R′3)] (R3P)2PtCl2 and C2H4 yield the compounds [{η2‐C2H4}Pt(PR3)2] (PR3 = PMe3, PEt3, PPhEt2, PPh2Et, PPh2Me, PPh2iPr, PPh2tBu and P(p‐Tol)3); which react with tBu2P–P=PMetBu2 to give the phosphinophosphinidene complexes [{η2‐tBu2P–P}Pt(PMe3)2], [{η2‐tBu2P–P}Pt(PEt3)2], [{η2‐tBu2P–P}Pt(PPhEt2)2], [{η2‐tBu2P–P}Pt(PPh2Et)2], [{η2‐tBu2P–P}Pt(PPh2Me)2], [{η2‐tBu2P–P}Pt(PPh2iPr], [{η2‐tBu2P–P}Pt(PPh2tBu)2] and [{η2‐tBu2P–P}Pt(P(p‐Tol)3)2]. [{η2‐tBu2P–P}Pt(PPh3)2] reacts with PMe3 and PEt3 as well as with tBu2PMe, PiPr3 and P(c‐Hex)3 by substituting one PPh3 ligand to give [{η2‐tBu2P1–P2}Pt(P3Me3)(P4Ph3)], [{η2‐tBu2P1–P2}Pt(P3Ph3)(P4Me3)], [{η2‐tBu2P1–P2}Pt(P3Et3)(P4Ph3)], [{η2‐tBu2P1–P2}Pt(P3MetBu2)(P4Ph3)], [{η2‐tBu2P1–P2}Pt(P3iPr3)(P4Ph3)] and [{η2‐tBu2P1–P2}Pt(P3(c‐Hex)3)(P4Ph3)]. With tBu2PMe, [{η2‐tBu2P–P}Pt(P(p‐Tol)3)2] forms [{η2‐tBu2P1–P2}Pt(P3MetBu2)(P4(p‐Tol)3)]. The NMR data of the compounds are given and discussed with respect to the influence of the PR3 ligands. 相似文献