Search results for "voltammetry"
showing 10 items of 404 documents
Synthesis, crystal structures and magnetic properties of mononuclear tris(croconate)ferrate(III) complexes
2006
Abstract A straightforward synthetic method to prepare mononuclear croconato-containing iron (III) complexes, (A)3[Fe(C5O5)3] [A = tetrabutylammonium = n-Bu4N+ (1) and tetraphenylphosphonium = PPh 4 + ( 2 ) ; C 5 O 5 2 - = croconate = dianion of 4 , 5 - dihydroxycyclopent - 4 - ene - 1 , 2 , 3 - trione ] along with their crystal structures and magnetic properties, are reported. The Fe(III) atom adopts a pseudo-octahedral geometry while magnetic susceptibility measurements, in the 2–300 K temperature range, show the occurrence of a high spin state (S = 5/2) in both complexes.
Oxidative nuclease activity of ferromagnetically coupled μ-hydroxo-μ-propionato copper(II) complexes [Cu3(L)2(μ-OH)2(μ-propionato)2] (L=N-(pyrid-2-yl…
2008
Three doubly-bridged, trinuclear copper(II) compounds with hydroxo and carboxylato bridges, ∞ 1 [Cu 3 (L1) 2 (μ-OH) 2 (μ-propionato) 2 ] ∞ 1 [ Cu 3 ( L 1 ) 2 ( μ - OH ) 2 ( μ - propionato ) 2 ] (1) , [Cu 3 (L2) 2 (μ-OH) 2 (μ-propionato) 2 (DMF) 2 ] (2) and ∞ 1 {[Cu 3 (L3) 2 (μ-OH) 2 (μ-propionato) 2 ]} ∞ 1 { [ Cu 3 ( L 3 ) 2 ( μ - OH ) 2 ( μ - propionato ) 2 ] } [Cu 3 (L3) 2 (μ-OH) 2 (μ-propionato) 2 (DMF) 2 ]} (3) [HL1 = N -(pyrid-2-ylmethyl)benzenesulfonylamide, HL2 = N -(pyrid-2-ylmethyl)toluenesulfonylamide, HL3 = N -(pyrid-2-ylmethyl)naphthalenesulfonylamide], have been synthesized and characterized. 1 is built from [Cu 3 (L1) 2 (μ-OH) 2 (μ-propionato) 2 ] clusters. Each unit contai…
Heterotetranuclear Complexes of Reduced and Non-reduced Bridging 1,2,4,5-Tetrazine Ligands with 1,1′-Bis(diphenylphosphanyl)-ferrocene-copper(I)
2015
The complexes {(μ-bptz)[Cu(dppf)]2}(BF4)2 [(1)(BF4)2] [bptz = 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine, dppf = 1,1′-bis(diphenylphosphanyl)ferrocene] and {(μ-bpztz)[Cu(dppf)]2}(PF6)2 [(2)(PF6)2] [bpztz = 3,6-bis(2-pyrazinyl)-1,2,4,5-tetrazine] contain two redox-active heterodinuclear FeIICuI moieties, bridged by a redox-active ligand. A crystal structure determination of (1)(BF4)2·2CH2Cl2 confirms the non-reduced aromatic nature of the bridge, in contrast to previous results on dicopper(I) complexes of bptz. Facile one-electron reduction produces the radical complexes {(μ-bptz)[Cu(dppf)]2}+ (1+) and {(μ-bpztz)[Cu(dppf)]2}+ (2+), which could be isolated [as (1)(BF4)] and studied by variable freq…
Synthesis, spectroscopic characterization and electrochemical behaviour of nickel(II) complexes with C-meso-5,5,7,12,12,14-hexamethylcyclotetradecane…
1993
A series of complexes of formula {Ni(Me6[14]aneN4)X2| (Me6[14]aneN4) = C-meso-5,5,7,12,12,14-hexamethyl-1,4,-8,11-tetraazacyclotetradecane and X = N3(1), NCO (2), NCS (3), AcO (4) or I (5) has been synthesized. The crystal structure of (5) has been determined by X-ray diffraction methods. The nickel atom is surrounded by a square-planar array of nitrogen atoms, giving a low-spin complex. The macrocyclic ligand shows the most stable conformation, the six-membered rings exhibiting the chair form while the gauche conformation is adopted by the five-membered rings. Spectroscopic and magnetic data for (1)–(4) are consistent with octahedral coordination around the nickel atom, which is achieved b…
Electrochemical behavior of layered annulenes
1985
Abstract The cyclic voltammetric behavior of a series of dimeric [14] annulenes was examined and compared with the monomer. The data suggest a signigficant degree of interaction between the annulene rings when a three-carbon chain connects them, little or no interaction with an eight-carbon chain, and weak interaction with a four-carbon chain.
Aminomethyl-Substituted Ferrocenes and Derivatives: Straightforward Synthetic Routes, Structural Characterization, and Electrochemical Analysis
2013
A variety of aminomethyl-substituted ferrocenes and the parent compounds (iminomethyl)ferrocenes, azaferrocenophanes, and diferrocenylamines can be selectively synthesized from reductive amination of 1,1′-diformylferrocene or formylferrocene. The optimized one- or two-step reactions have delivered 13 new compounds, isolated in 65–97% yields, which include tertiary (ferrocenylmethyl)amines and azaferrocenophanes by using NaBH(OAc)3 as a mild reducing agent and (iminomethyl)ferrocenes and secondary (ferrocenylmethyl)amines by using LiAlH4. X-ray structures of representative members of these ferrocene derivative families have evidenced the preferred conformation adopted by ferrocene backbones,…
Molybdenum(VI)-dioxo complexes with sterically bulky thiocarboxylate ligands. Reactions with aliphatic thiols and electrochemical properties
1991
Abstract Under acid conditions, the reaction of (Bu n 4 N)2[Mo VI O 2 (O 2 CC(S)Ph 2 ) 2 ] with aliphatic thiols yields the monomeric [Mo V O(O 2 CC(S)Ph 2 ) 2 ] − as unique complex product. The experimental pseudo-first order rate constant with respect to the Mo(VI) complex was found to be K =6.1 × 10 −5 s −1 . At neutral pH, however, an unstable Mo(IV) species was formed which was also electrochemically detected in a reversible Mo(V,IV) couple. [Mo V O(O 2 CC(S)Ph 2 ) 2 ] − appears to be obtained by the reaction of [Mo IV O(O 2 CC(S)Ph 2 ) 2 ] 2− with unreacted [Mo VI O 2 (O 2 CC(S)Ph 2 ) 2 ] 2− . Steric features on the ligand (gemdiphenyl groups) explain that the latter reaction does not…
Electrochemical determination of boron in minerals and ceramic materials
2004
Abstract A method for quantitatively determining boron in minerals and ceramic materials is described. It is based on the abrasive attachment of mixtures of ZnO plus sample to PIGEs. After a reductive deposition step, square wave voltammograms recorded for those modified electrodes immersed into 0.10 M NaCl+0.25 M mannitol provide well-defined stripping peaks at −0.85 and −0.15 V vs. AgCl/Ag for the oxidation of Zn and B, respectively. The quotients between the peak areas and the peak currents for the stripping oxidation of B and Zn vary linearly with the molar ratio of B and Zn in the mixture, thus providing an electrochemical method for determining the boron content in solid samples. Resu…
Chalcogenide-capped triiron clusters [Fe3(CO)9(μ3-E)2], [Fe3(CO)7(μ3-CO)(μ3-E)(μ-dppm)] and [Fe3(CO)7(μ3-E)2(μ-dppm)] (E = S, Se) as proton-reduction…
2019
Chalcogenide-capped triiron clusters [Fe3(CO)7(μ3-CO)(μ3-E)(μ-dppm)] and [Fe3(CO)7(μ3-E)2(μ-dppm)] (E = S, Se) have been examined as proton-reduction catalysts. Protonation studies show that [Fe3(CO)9(μ3-E)2] are unaffected by strong acids. Mono-capped [Fe3(CO)7(μ3-CO)(μ3-E)(μ-dppm)] react with HBF4.Et2O but changes in IR spectra are attributed to BF3 binding to the face-capping carbonyl, while bicapped [Fe3(CO)7(μ3-E)2(μ-dppm)] are protonated but in a process that is not catalytically important. DFT calculations are presented to support these protonation studies. Cyclic voltammetry shows that [Fe3(CO)9(μ3-Se)2] exhibits two reduction waves, and upon addition of strong acids, proton-reducti…
Synthesis, Optical and Electrical Properties of Oligo(phenylenevinylene)s Substituted with Electron-Accepting Sulfonyl Groups
2010
Oligo(phenylenevinylene)s (OPV) composed of five rings and electron donating or withdrawing sulfonyl substituents on the central and lateral rings have been investigated. Two strategies were used for the syntheses of the C2-symmetrical OPVs both include PO-activated olefinations as central steps. Six flexible side chains guarantee good solubility in toluene or dichloromethane. In solution and in films stabilised by polystyrene (60%), the chromophores are strongly fluorescent, with emissions in the violet-blue domain from solutions and in the green to orange region from solid films. The redox potentials, determined by cyclic voltammetry, and the optical properties are strongly depending on t…