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Organometallic Compounds (organometallic + compound)

Distribution by Scientific Domains

Chemistry	94%

Selected Abstracts

Mediated Electron Transfer Across Supported Bilayer Lipid Membrane with TCNQ-Based Organometallic Compounds

ELECTROANALYSIS, Issue 4 2010
Meili Qu
Abstract Supported bilayer lipid membrane (s-BLM) containing one-dimensional compound 1, TCNQ-based (TCNQ=7,7,8,8-tetracyanoquinodimethane) organometallic compound {(Cu2(,-Cl)(,-dppm)2)(,2 -TCNQ)},, was prepared and characterized on the self-assembled monolayer (SAM) of 1-octadecylmercaptan (C18H37SH) deposited onto Au electrode. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results showed that the compound 1, dotted inside s-BLM, can act as mediator for electron transfer across the membrane. Two redox peaks and the charge-transfer resistance of 400,k, were observed for compound 1 inside s-BLM. The mechanism of the electron transfer across s-BLM by TCNQ is by electron hopping while TCNQ-based organometallic compound is by conducting. Further conclusion drawn from this finding is that the TCNQ-based organometallic compound embedded inside s-BLM exhibits excellent electron transfer ability than that of free TCNQ. This opens a new path for the development of s-BLM sensor and/or biosensor by incorporation with TCNQ-based organometallic compounds. [source]

Addition of Organometallic Compounds to Tin-Containing Cyclic Ketones.

CHEMINFORM, Issue 5 2004
Remote Stereocontrol Induced by the Stannyl Group.
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Powder second harmonic generation measurement and thermal decomposition mechanisms of a new organometallic compound [(18C6)Li][Cd(SCN)3]

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 9 2009
J. J. Zhang
Abstract Single crystals of a novel nonlinear optical organometallic compound CLTC, ([(18C6)Li][Cd(SCN)3]), were grown from aqueous solutions via evaporation technique and characterized by IR spectroscopy, thermal gravimetric analysis and X-ray single-crystal diffraction. By X-ray single-crystal structural analysis it is revealed that the compound crystallized in a noncentrosymmetric space group Cmc21 of orthorhombic system with cell parameter a = 14.767(3) Å, b = 15.454(3) Å, c = 10.644(2) Å, V = 2429.0(8) Å3 and Z = 4. The thermal stability and thermal decomposition of CLTC crystal were investigated by means of thermogravimetry and differential thermal analysis. The second harmonic generation (SHG) efficiency was measured using the Kurtz and Perry powder technique. It was shown that the value of the SHG efficiency of CLCT powder was about 2 times higher than that of potassium dihydrogen phosphate (KDP). (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Mediated Electron Transfer Across Supported Bilayer Lipid Membrane with TCNQ-Based Organometallic Compounds

The conversion of an organometallic compound into an intercalated thin-layer amorphous structure

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 10 2009
M. R. Othman
Abstract A thin alumina-hydrotalcite (Al-HT) film was fabricated from the synthesized boehmite and HT sol samples. The sols were a Newtonian fluid within 12 h of the sol synthesis and pseudo-plastic flow thereon. Co-precipitated HT demonstrated poorly crystallized periclase and spinel structures and apparent doublet peak of hydrotalcite at 2, = 39,44°, indicative of a disordered structure. The heated Al-HT sample demonstrated highly amorphous structure with single hydrotalcite peak but barely observed ,-alumina and ,-boehmite phases. The exfoliation of the spinel, gibbsite and periclase in the Al-HT was caused by the intercalation of boehmite into the HT layers that impeded the formation of the oxides phases. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Preparation, characterization and biological activities of novel ferrocenyl-substituted azaheterocycle compounds

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 3 2003
Jian-Xin Fang
Abstract ,-Haloacetylferrocene and ,-triazolylacetylferrocene have been prepared from acetylferrocene and they have proved to be useful building blocks for the synthesis of ferrocenyl propenone. Two new types of ferrocenyl vinyl triazole compound, (Z,E)-ferrocenyl-[1-(1,2,4-triazol-1-yl)-2-phenyl]-vinyl-ones, have been synthesized and their structures characterized by crystal X-ray diffraction analysis. It has been shown for the first time that ferrocene, as an organometallic compound, has been introduced into bioactive triazole compounds in search of potent bioactive substances. Their biological activities are also discussed. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Mediated Electron Transfer Across Supported Bilayer Lipid Membrane with TCNQ-Based Organometallic Compounds

EPR Insensitivity of the Metal-Nitrosyl Spin-Bearing Moiety in Complexes [LnRuII -NO·]k

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2004
Stéphanie Frantz
Abstract A survey of 18 paramagnetic species [LnRu(NO)]k, including seven new examples studied by in situ electrolysis, reveals a surprisingly narrow range of EPR parameters despite a wide variety of ligands such as pyridine, polypyridines, imines, amines, nitriles, phosphanes, carbonyl, cyclopentadienides, halides, hydride, hydroxide, thiocyanate or cyanide: g1 = 2.015 ± 0.02, g2 = 1.990 ± 0.015, g3 = 1.892 ± 0.03, gav = 1.968 ± 0.02, ,g = g1 , g3 = 0.122 ± 0.037, A2(14N) = 3.3 ± 0.5 mT. This rather small variability, smaller still if the organometallic compounds are excluded, differs from the wider range of EPR data reported for nitrosyliron species with S = 1/2; apparently, the {RuNO}7 configuration involves a rather invariant and relatively covalent metal,NO interaction. DFT calculations were employed for [(NC)5Ru(NO)]3, to reproduce the EPR data, to evaluate the spin distribution (58% spin density on NO), and to reveal structural changes on reduction such as the Ru,N,O bending and Ru,NO bond lengthening. In addition, the possibility of staggered and eclipsed conformations is discussed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]

Band composition analysis: a new procedure for deconvolution of the mass spectra of organometallic compounds

JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 8 2003
Jacek A. Szymura
Abstract A new chemometric procedure called band composition analysis (BCA) designed for the deconvolution of mass spectra of organometallics is proposed. BCA generates theoretical bands Ti, then combines them to obtain a model band M, which is finally compared with the experimental band E. All of these steps are realized with computer assistance. This modeling yields four parameters characterizing the experimental band: theoretical and model variances s2theor and s2model, a fit factor , and a contribution xi from the theoretical band. If s2theor > 20 the band is deemed complex and needs modeling. The values , > 90 indicate that there is good agreement between the experimental and model bands. BCA is particularly effective for the modeling of complex isotopic bands often present in organometallics. Two illustrations of BCA for tetrabutyltin, C16H36Sn, and 1,1,,2,2,,3,3,-hexachloroferrocene, C10H4Cl6Fe, are shown. Copyright © 2003 John Wiley & Sons, Ltd. [source]

An ESR and electrochemical approach to the unusual reactivity of ferrocenoylsilanes with organometallic compounds

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 12 2004
A. Alberti
Abstract ESR studies carried out during the reaction of ferrocenoylsilanes with Grignard reagents at low temperature led to the detection of the radical anions of the former compounds. Cyclic voltammetric experiments indicate that the observed radical anions are likely to originate through an inner-sphere electron transfer process. Different radical species were observed upon annealing, originating from destruction of the ferrocenyl moiety. Paramagnetic species were also detected on reacting ferrocenoylsilanes with LiAlH4. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Probing interactions by means of pulsed field gradient nuclear magnetic resonance spectroscopy,

MAGNETIC RESONANCE IN CHEMISTRY, Issue S1 2008
Sara Cozzolino
Abstract Molecular self-diffusion coefficients (D) of species in solution are related to size and shape and can be used for studying association phenomena. Pulsed field gradient nuclear magnetic resonance (PFG-NMR) spectroscopy has been revealed to be a powerful analytical tool for D measurement in different research fields. The present work briefly illustrates the use of PFG-NMR for assessing the existence of interactions in very different chemical systems: organic and organometallic compounds, colloidal materials and biological aggregates. The application of PFG-NMR is remarkable for understanding the role of anions in homogenous transition metal catalysis and for assessing the aggregation behaviour of biopolymers in material science. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Novel ferrocenyl phosphonate derivatives.

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 10 2010
Inhibition of serine hydrolases by ferrocene azaphosphonates
Abstract Owing to their unique properties, ferrocene compounds are gaining increasing interest for biological applications, particularly as enzyme inhibitors. Phosphonate derivatives including a ferrocenyl moiety were synthesized by reaction of dimethyl- and diphenylphosphite with ferrocenyl methyl maleimide. The ferrocenyl diphenyl phosphonate complex was characterized by X-ray diffraction. The ability of these organometallic compounds to inhibit the enzymatic activity of the serine esterases acetyl- and butyrylcholinesterase was investigated. It appeared that the new ferrocenyl phosphonates inhibited both enzymes by competitive, mixed or non competitve mechanisms with inhibition constants in the range 35,1000 µM. Both compounds also behave as slow time-dependent inactivators of butyrylcholinesterase. The presence of the ferrocenyl entity seems then to have a dramatic effect on the biochemical behavior of the systems. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Sequestration of organometallic compounds by natural organic matter. binding of trimethyltin(IV) by fulvic and alginic acids

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 10 2006
Alba Giacalone
Abstract The binding capacity of fulvic and alginic acids towards trimethyl tin(IV) cation was quantitatively determined in order to evaluate the sequestering ability of toxic organometallic compounds by natural organic matter. Investigations were performed in the pH range of natural waters (5,8.5) where the carboxylate groups, largely present in both sequestering agents, are the main binding sites. A chemical interaction model, according to which both the protonation of polyelectrolyte ligands and the hydrolysis of the organotin cation in NaCl aqueous solution were considered, was used to define the speciation of the systems under investigation. Measurements performed at different ionic strength values (0.1, 0.25, 0.5 and 0.7 mol L,1, NaCl) allowed us to consider the dependence of stability constants on the ionic strength, and to calculate the formation constants at infinite dilution. Results obtained show the formation of the complex species TMT(L), TMT(L)2 and TMT(L)(OH) for L = fulvic acid and TMT(L) for L = alginic acid, respectively. In order to compare the strength of interaction of these natural poly electrolytes with other analogous synthetic polyelectrolytes, measurements were also carried out on the trimethyltin(IV),polyacrylate (5.1 kDa) system, and in this case the formation of TMT(L), TMT(L)2 and TMT(L)(OH) species was found. Results show the following trend of stability for the species TMT(L) in the systems investigated: TMT,fulvate , TMT,polyacrylate > TMT,alginate. On the basis of the stability data obtained, the lowest concentration of fulvic and alginic acids, able to act as sequestering agents towards triorganotin(IV) cation in the conditions of natural waters, was also calculated. Copyright © 2006 John Wiley & Sons, Ltd. [source]

The analysis of volatile trace compounds in landfill gases, compost heaps and forest air

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 3 2003
Sarah Maillefer
Abstract Landfill gas, cryotrapped on a loop fashioned from a length of a capillary gas chromatography (GC) column, was examined for volatile organometallic compounds (VOMCs) and for volatile organic compounds (VOCs) by using GC,mass spectrometry (MS). A large number of organic components were present and many were identified, but the only VOMCs present in high enough concentrations to be detected were trimethylstibine and tetramethyltin. The use of inductively coupled plasma (ICP)-MS as an element-specific detector allowed the identification of a number of other organometallic species in the landfill gas, including trimethylarsine and trimethylbismuth, and, for the first time, butyltrimethyltin and dibutyldimethyltin. The presence of molybdenum hexacarbonyl was confirmed. Gas from a large-scale compost heap and from compost incubated in the laboratory contained iodomethane but no common VOMCs (GC,ICP-MS). Only VOCs were present in forest air (GC,MS). Copyright © 2003 John Wiley & Sons, Ltd. [source]

Recent Synthetic Applications of Manganese in Organic Synthesis

CHEMISTRY - A EUROPEAN JOURNAL, Issue 33 2008

Abstract While the organometallic compounds derived from many metals have found a broad application in organic synthesis, the use of organomanganese compounds has only recently been developed due to the passivity exhibited by commercial Mn in the direct metalation of organic compounds. In this Concept article, we highlight the potential of manganese and its organometallic compounds in organic synthesis by illustration of the studies previously reported by others and our laboratory in this field. Based on the transformations reported herein, organomanganese compounds could become important tools in the future of the organic synthesis, due to their high selectivity. [source]

Preferred Functionalization of Metallic and Small-Diameter Single-Walled Carbon Nanotubes by Nucleophilic Addition of Organolithium and -Magnesium Compounds Followed by Reoxidation

CHEMISTRY - A EUROPEAN JOURNAL, Issue 5 2008
David Wunderlich Dipl.-Chem
Abstract Covalent sidewall addition to single-walled nanotubes (SWNTs) of a series of organolithium and organomagnesium compounds (nBuLi, tBuLi, EtLi, nHexLi, nBuMgCl, tBuMgCl) followed by reoxidation is reported. The functionalized Rn -SWNTs were characterized by Raman and NIR emission spectroscopy. The reaction of SWNTs with organolithium and magnesium compounds exhibits pronounced selectivity: in general, metallic tubes are more reactive than semiconducting ones. The reactivity of SWNTs toward the addition of organometallic compounds is inversely proportional to the diameter of the tubes. This was determined simultaneously and independently for both metallic and semiconducting SWNTs. The reactivity also depends on the steric demands of the addend. Binding of the bulky t- butyl addend is less favorable than addition of primary alkyl groups. Significantly, although tBuLi is less reactive than, for example, nBuLi, it is less selective toward the preferred reaction with metallic tubes. This unexpected behavior is explained by fast electron transfer to the metallic SWNTs having low-lying electronic states close to the Fermi level, a competitive initial process. The NIR emission of weakly functionalized semiconducting SWNTs, also reported for the first time, implies interesting applications of functionalized tubes as novel fluorescent reporter molecules. [source]