Search results for "TRIP"
showing 10 items of 2134 documents
2D and 3D bimetallic oxalate-based ferromagnets prepared by insertion of MnIII-salen type complexes
2013
The syntheses, structures and magnetic properties of the compounds of formulae [Mn((R)-salmen)(CH3OH)(CH3CN)][MnCr(ox)3](CH3OH)0.5(CH3CN)1.25 ((R)-1), [Mn((S)-salmen)(CH3OH)(CH3CN)][MnCr(ox)3](CH3OH)0.5(CH3CN)1.25 ((S)-1), [Mn((R)-salmen)(CH3OH)2][MnCr(ox)3](CH2Cl2)0.375(CH3OH)0.125(H2O)0.375 ((R)-2) and [Mn((S)-salmen)(CH3OH)2][MnCr(ox)3](CH2Cl2)0.375(CH3OH)0.375(H2O)0.125 ((S)-2) (ox = oxalate, salmen2− = N,N′-(1-methylethylene)bis(salicylideneiminate)), [Mn(salpn)(CH3OH)1.5(CH3CN)0.5][MnCr(ox)3](CH3OH)0.82(H2O)0.93 (3) (salpn2− = N,N′-(propane)bis(salicylideneiminate)) and [Mn(saltmen)(CH3OH)(CH3CN)][MnCr(ox)3](CH3OH) (4) (saltmen2− = N,N′-(1,1,2,2-tetramethylethylene)bis(salicylideneimi…
Anodic stripping voltammetric determination of heavy metals in solutions containing humic acids
1994
Various simultaneous effects of humic acids on the current and potential of differential pulse anodic stripping peaks of copper, lead, cadmium and zinc in weakly alkaline and acidic (pH 2) solutions have been investigated and interpreted with regard to metal complexation and the adsorption of humic acid on the mercury electrode. The applicability of the standard additions method for metal quantitation and the experimental conditions for UV-photolysis with a high-pressure mercury lamp have been examined in model as well as real water samples.
Effect of ethylenediamine on the anodic stripping voltammetric determination of heavy metals in the presence of humic acid
1994
Ligand competition coupled with differential pulse anodic stripping voltammetry has been investigated for the determination of copper, lead and cadmium. Ethylenediamine displaces humic acid in its metal complexes forming kinetically labile compounds. It also eliminates interferences associated with the oxidation of copper. This enhances the sensitivity of the determination of the metals over a wide range of humic acid concentration (up to 30 mg/l). The procedure has been applied to the determination of heavy metals in a real water sample.
Differential reactivity of fluorinated homopropargylic amino esters vs gold(I) salts. The role of the nitrogen protecting group
2015
The reaction of several homopropargyl amino esters 4, bearing aromatic substituents and a benzyl group as nitrogen substituents, with gold(I) salts gave rise to fluorinated quinolines 6 in a tandem hydroarylation-isomerization process. On the other hand, homopropargyl amino esters 7 containing a carbamate group underwent the carbonyl addition over the triple bond in the presence of gold(I) salts, rendering fluorinated oxazines 8. The use of chiral sulfoxides allowed us to develop the asymmetric version of this protocol. This two processes complete the differential reactivity showed by these types of susbtrates, depending on the nature of the nitrogen protecting group. (C) 2014 Elsevier B.V.…
Controlling the dimensionality of oxalate-based bimetallic complexes: The ferromagnetic chain {[K(18-crown-6)][Mn(bpy)Cr(ox)3]}∞(18-crown-6=C12H24O6,…
2007
Abstract The bimetallic ferromagnetic chain {[K(18-crown-6)][Mn(bpy)Cr(ox)3]}∞ (1) has been synthesized and characterized. It crystallizes in the orthorhombic chiral space group P212121 [a = 9.0510(2) A, b = 14.4710(3) A, c = 26.8660(8) A, V = 3510.97(1) A3, Z = 2]. Compound 1 is made up by anionic [Mn(bpy)Cr(ox)3]− 1D chains and cationic [K(18-crown-6)]+ complexes. The magnetic exchange within the chain is ferromagnetic [J = +7.8(7) cm−1]. In the solid state, the ferromagnetic chains are well isolated magnetically and no long range magnetic ordering has been observed above 2 K.
The structure of a dinuclear silver(I) complex: Ag2[S2C2(CN)2] [P(C6H5)3]4
1986
Abstract The crystal structure of the dimeric Ag maleonitriledithiolate complex, Ag2[S2C2(CN)2] [P(C6- H5)3]4 (1), has been performed. Complex 1 crystallizes in the space group P21/c with a = 12.2898(77), b = 23.8325(91), c = 23.1790(118) A, β = 101.315(43)° and Z = 4. Refinement using 3253 reflections with Fo2>3σ(Fo2) yielded R = 0.0662, Rw= 0.0669. The most interesting aspect of the structure is the strong bridging interaction of the chelating maleonitriledithiolate ligand with the second Ag center, where a Ag-S distance of 2.478 A is observed. The residual bonding capability of the sulfur atoms in the chelating anion [Ag(S2C2(CN)2)(PPh3)2]− for [Ag(PPh3)2]+ is demonstrated.
Morphological transformations in a dually thermoresponsive coil-rod-coil bioconjugate.
2013
We report the conformational and assembly behavior of a thermoresponsive triblock biohybrid conjugate under aqueous conditions. The triblock comprises of poly(diethylene glycol methyl ether methacrylate) (PDEGMEMA) conjugated to the ends of a triple-helix forming collagen-like peptide. The circular dichroism (CD) experiment confirms the ability of the collagen-like peptide middle block to assemble as a triple helix in the hybrid conjugate. Above the LCST (∼35 °C), the collapse of the thermoresponsive PDEGMEMA polymer at the ends of the peptide domain resulted in a concomitant increase in the conformational stability of the peptide domain towards thermal denaturation. Upon cooling back, the …
Light-induced demixing of hole or electron transporting moieties
2004
This paper describes the synthesis of two tri-phenylamine monomers (hole conducting) and one triazine monomer (electron conducting) which differ in their copolymerization parameters because of their styrene and vinyl ester nature. A blend of triphenylamine monomer and poly-(ethylene glycol) and mixtures of both types of monomers (triphepylamine and triazine) were illuminated through a line mask, creating laterally modulated radicals, thus leading to lateral demixing. The experiments with mixtures of triphenylamine and triazine monomers show that the concentration of p- or n-type polymers can be modulated laterally in a controlled way.
Bimetallic cyanide-bridged complexes based on the photochromic nitroprusside anion and paramagnetic metal complexes
2001
Abstract Three novel compounds formed by the photochromic nitroprusside anion, [Fe(CN)5NO]2−, and the paramagnetic complexes [Cu(C19H18N6)]2+, [Ni(C6H14N2)2]2+ and [Ni(cyclam)]2+ are reported. The structure of [Cu(C19H18N6)][Fe(CN)5NO] (1) comprises binuclear complexes with a [Fe(CN)5NO]2− anion linked to a [Cu(C19H18N6)]2+ cation. The structure of [Ni(C6H14N2)2][Fe(CN)5NO]·6.5H2O (2) and [Ni(cyclam)][Fe(CN)5NO]·4H2O (3) consists of zigzag chains formed by an alternate array of the paramagnetic cations and [Fe(CN)5NO]2− anions. The three compounds are paramagnets; a fourth compound containing [cis-Ni(en)2]2+ cations and [Fe(CN)5NO]− anions does not show a change in the magnetic properties a…
Straightforward Stereoselective Access to Cyclic Peptidomimetics
2009
The preparation of cyclic dipeptide mimetics from chiral imino lactones derived from (R)-phenylglycinol is described. Key steps of the synthetic route included the fully stereoselective construction of a quaternary center, the formation of six-, seven-, or eight-membered lactams by means of an RCM cyclization, and the introduction of a new amino group within the lactam ring. The synthesis of a tripeptide mimetic is also reported.