EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 6 2007
Detlef Schröder
Abstract Mass spectrometry is used to investigate the fragmentation of the ligated azidoiron cation [(cyclam-acetato)Fe(N3)]+, which is accessible in the gas phase by electrospray ionization of a solution of its hexafluorophosphate salt in methanol/water. Upon collisional activation, mass-selected [(cyclam-acetato)Fe(N3)]+ undergoes competing loss of dinitrogen or HN3 as the prevailing fragmentations. The former dissociation pathway is investigated in detail in order to determine whether or not the free, high-valent iron nitride [(cyclam-acetato)FeN]+ is formed. The evidence obtained indeed supports the formation of the iron nitride species as an intermediate, although the long-lived ion sampled after mass selection may also have undergone further rearrangements.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

On the Photochemical Stability of the 9-Mesityl-10-methylacridinium Cation

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 2 2009
Andrew C. Benniston
Abstract The 9-mesityl-10-methylacridinium cation in aerated deuterated/normal acetonitrile decomposes to give several side products when continuously exposed to white light. The main breakdown product isolated by column chromatography is identified as 3,5-dimethyl-4-(10-methylacridinium)benzaldehyde. This assignment was confirmed by single-crystal X-ray crystallography. In light of these findings it appears that decomposition pathways also need to be considered when discussing the photochemical properties of the 9-mesityl-10-methylacridinium cation, especially in the presence of dioxygen.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

Radical Cation and Dication Derived from 4,8-Diethylbenzo[1,2- d:4,5- d,]bis[1,2,3]trithiole [DEBBT]: Change of Electronic State from Singlet-State Dication DEBBT(2+)- S to Triplet-State Dimer 2DEBBT(2+)- T in D2SO4 and CD3CN Solutions

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 24 2003
Takeshi Kimura
Abstract 4,8-Diethylbenzo[1,2- d:4,5- d,]bis[1,2,3]trithiole [DEBBT] was oxidized using concentrated D2SO4, leading to the generation of the radical cation DEBBT(·+) which was verified by ESR spectroscopy. DEBBT(·+) in the solution was further oxidized to produce the dication DEBBT(2+), as determined by 1H and 13C NMR spectroscopy. DEBBT(2+) was also prepared by treating DEBBT 1-oxide [DEBBT 1-O] with concentrated D2SO4, and was verified by 1H and 13C NMR spectroscopy. The 13C NMR chemical shifts of DEBBT(2+), calculated by the density functional theoretical (DFT) method at the B3LYP6-31G** level, correlated well with those obtained experimentally. The ESR signal of DEBBT(2+) generated from DEBBT 1-O was observed in solution, which implies that the singlet-state dication DEBBT(2+)- S isomerizes to the triplet-state dication DEBBT(2+)- T, and that two molecules of DEBBT(2+)- T further form a spin pair at one trithiole ring with significant distance between the two radical centers. The oxidation of DEBBT with one or two equivalents of single-electron oxidizing reagents produced DEBBT(·+) and DEBBT(2+), and the salts were isolated in a stable form. However, the DEBBT(2+) that was prepared by oxidation with NOPF6 proved silent for NMR in CD3CN, while ESR was active. The stability, electronic state, and NMR and ESR spectroscopy of the dication are affected by solvation with D2SO4 and CD3CN. The optimized structures and the total energy of the singlet- and triplet-state dication were calculated using the DFT method at the B3LYP6-31G** level, which shows that the structures of the singlet- and triplet-state dications have a completely planar form with 1.7 kcal/mol as the total energy difference between them. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

Cation,, complexes of a bowl-shaped polycyclic aromatic hydrocarbon

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 9 2004
Ronald B. M. Ansems
Abstract Circumtrindene (1), a C36H12 geodesic polyarene that represents 60% of fullerene-C60, forms cation,, complexes with both silver ion (1·Ag+) and tetramethylammonium ion [(Me)4N+·1] in chloroform solution at room temperature (Ka>20,M,1 for both cations). Preferential binding in the concave pocket of 1 is predicted by DFT calculations for both cations; however, this stereochemical assignment has not yet been confirmed experimentally. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Development of a liquid chromatography/electrospray selected reaction monitoring method for the determination of organoarsenic species in marine and freshwater samples

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 19 2006
Richard Schaeffer
Cation- and anion-exchange high-performance liquid chromatography/electrospray selected reaction monitoring (HPLC/ES-SRM) methods were developed for the determination of 15 organoarsenic compounds in marine and freshwater samples. The results demonstrate that the developed HPLC/ES-SRM methods are powerful approaches for the identification of organoarsenic species in crude sample extracts. The detection limits, linearity as well as reproducibility for most of the species are comparable or even better than those measured by the HPLC/inductively coupled plasma mass spectrometry (ICPMS) technique. The qualitative analysis of the extracts shows that the developed methods allow for the identification of arsenicals which were not detectable by ICPMS. It was also demonstrated that the signal suppression caused by matrix effects means a significant limitation in the quantification of arsenicals by ES-SRM detection. This drawback is manifested especially in the case of the slightly retained species. The three sample-cleanup chromatographic methods including off-line size-exclusion, on-line reversed-phase and on-line oppositely charged ion-exchange approaches proved to be ineffective for separation of the signal-suppressive matrix from the analytes. The standard addition calibration seems to be a suitable solution for such problems. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Isolation of a Carbene-Stabilized Phosphorus Mononitride and Its Radical Cation (PN+.),

ANGEWANDTE CHEMIE, Issue 34 2010
Rei Kinjo Dr.
Carbene stechen Metalle aus: Phosphormononitrid-Übergangsmetall-Komplexe wurden bisher nicht isoliert, doch ein PN-Fragment mit zwei sperrigen, stark elektronenschiebenden Singulettcarbensubstituenten lässt sich bei Raumtemperatur synthetisieren (siehe Bild; P,rot, N,blau, C,grau). Einelektronenoxidation lieferte das entsprechende stabile Radikalkation. [source]

Facile Generation of a Strained Cyclic Vinyl Cation by Thermal Solvolysis of Cyclopent-1-enyl-,3 -bromanes,

ANGEWANDTE CHEMIE, Issue 47 2009
Kazunori Miyamoto Prof.
Bromhaltige Abgangsgruppe: Die einfache Solvolyse von Cyclopent-1-enyl-,3 -bromanen bei Raumtemperatur liefert das stark gespannte Cyclopent-1-enyl-Kation (siehe Schema). Diese außergewöhnliche unimolekulare Dissoziation beruht auf der Wirkung der Aryl-,3 -bromanyl-Gruppen als gute Abgangsgruppen. [source]

Innentitelbild: Stable Pentavalent Uranyl Species and Selective Assembly of a Polymetallic Mixed-Valent Uranyl Complex by Cation,Cation Interactions (Angew. Chem.

ANGEWANDTE CHEMIE, Issue 45 2009
45/2009)
Oligomere Komplexe mit kationischen Actinyleinheiten sind entscheidend für die Aufarbeitung von radioaktivem Abfall und die Verteilung von Actinoiden in der Umwelt. In ihrer Zuschrift auf S.,8629,ff. zeigen M. Mazzanti et,al., dass der N,N,-Bis(salicyliden)ethylendiamin-Ligand (Salen) fünfwertiges Uran stabilisieren kann. Ein entsprechender Vierkernkomplex, in dem eine antiferromagnetische Kopplung zwischen den vier oxoverbrückten Uranzentren vorliegt, ist stabil gegen Disproportionierung und Hydrolyse. [source]

Stable Pentavalent Uranyl Species and Selective Assembly of a Polymetallic Mixed-Valent Uranyl Complex by Cation,Cation Interactions,

ANGEWANDTE CHEMIE, Issue 45 2009
Victor Mougel
Nützliche Verbindung: Vier Salenkomplexe von fünfwertigen Uranylionen aggregieren zu einem Vierkernkomplex, der sehr beständig gegen Disproportionierung und Hydrolyse ist und eine deutliche antiferromagnetische Kopplung zwischen den vier oxoverbrückten Uranzentren aufweist (siehe Bild: O,rot, U,grün). Ausgehend von diesem Komplex wurde auch die erste gemischtvalente UV3/UVI -Verbindung selektiv synthetisiert. [source]

Trifluoromethanesulfanylamides as Easy-to-Handle Equivalents of the Trifluoromethanesulfanyl Cation (CF3S+): Reaction with Alkenes and Alkynes,

ANGEWANDTE CHEMIE, Issue 45 2009
Aurélien Ferry Dr.
Elegant eingeführt: Die CF3S-Einheit lässt sich mithilfe des Trifluormethansulfanylamid-Reagens elektrophil an Alkene und Alkine addieren (siehe Schema; Ts=Toluol-4-sulfonyl). Die erhaltenen Produkte könnten beispielsweise in der pharmazeutischen Chemie und den Materialwissenschaften von Interesse sein. [source]

A Spiro-Fused Triarylaminium Radical Cation with a Triplet Ground State,

ANGEWANDTE CHEMIE, Issue 32 2009
Akihiro Ito Dr.
No abstract is available for this article. [source]

HeLa Cell Entry by Guanidinium-Rich ,-Peptides: Importance of Specific Cation,Cell Surface Interactions

CHEMBIOCHEM, Issue 8 2007
Terra B. Potocky
Abstract Short cationic oligomers, including arginine-rich peptides and analogous ,-amino acid oligomers (", -peptides"), can enter the cytoplasm and nucleus of a living cell from the extracellular medium. It seems increasingly clear that multiple entry pathways are possible, depending upon the structure of the guanidinium-rich molecule, the type of cell, and other factors. We have previously shown that conformational stability and spatial clustering of guanidinium groups increase the HeLa cell entry efficiency of short helical , -peptides bearing six guanidinium groups, results that suggest that these , -peptides could be useful tools for studying the entry process. Here we describe studies intended to identify the point in the entry process at which helix stability and spatial arrangement of guanidinium groups exert their effect. Our results suggest that key distinctions involve the mode of interaction between different guanidinium-rich ,-peptides and the HeLa cell surface. A specific guanidinium display appears to be required for proper engagement of cell-surface heparan sulfate proteoglycans and concomitant induction of endocytic uptake. [source]

ChemInform Abstract: Structure and Aromaticity of B6H5+ Cation: A Novel Borhydride System Containing Planar Pentacoordinated Boron

CHEMINFORM, Issue 23 2009
Hong-Lang Yu
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

ChemInform Abstract: Arenium Cation as the Key Intermediate of the Electrosynthesis of N-(2,5-Dimethoxyphenyl)azoles.

CHEMINFORM, Issue 39 2008
A New Approach to the Synthesis of N-(Dimethoxyphenyl)azoles.
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

ChemInform Abstract: A Polyoxometalate-Templated Inorganic,Organic Hybrid Compound Containing a Crown-Like Metallamacrocyclic Cation [Ag6(1,2,4-Triazole)6]6+.

CHEMINFORM, Issue 30 2008
Xiang-Min Chen
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

ChemInform Abstract: Naphthidine Di(radical Cation)s-Stabilized Palladium Nanoparticles for Efficient Catalytic Suzuki,Miyaura Cross-Coupling Reactions.

CHEMINFORM, Issue 24 2008
Christophe Desmarets
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

One-Dimensional Array of Two- and Three-Center Cation,Cation Bonds in the Structure of Li4 [(UO2)10O10(Mo2O8)].

CHEMINFORM, Issue 52 2007
Evgeny V. Alekseev
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

A Novel Category of Ionic Liquids Based on Diacetone Acrylamide Cation and Their Use as Esterification Catalysts.

CHEMINFORM, Issue 9 2007
Qing-Hai Cai
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Bifunctional Materials Based on the Photochromic Cation [RuNO(NH3)5]3+ with Paramagnetic Metal Complex Anions.

CHEMINFORM, Issue 52 2006
Lyudmila A. Kushch
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Effect of Tetrabutylphosphonium Cation on the Physico-Chemical Properties of Amino Acid Ionic Liquids.

CHEMINFORM, Issue 37 2006
Junko Kagimoto
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Spectroscopic, Magnetochemical, and Crystallographic Study of Cesium Iron Phosphate Hexahydrate: Characterization of the Electronic Structure of the Iron(II) Hexa-aqua Cation in a Quasicubic Environment.

CHEMINFORM, Issue 35 2006
Graham Carver
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Regioselectivity in Nucleophilic Addition of Siloxyalkenes to an Alkylideneallyl Cation.

CHEMINFORM, Issue 35 2006
Morifumi Fujita
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Convenient Preparation and Full Characterization of a Synthetically Useful Salt of the Dithianitronium Cation, SNSSbF6, from Readily Available Starting Materials.

CHEMINFORM, Issue 49 2005
T. Stanley Cameron
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Degenerate Rearrangement of 9,10-Dimethyl-9-(cis-1-methylprop-1-enyl)phenanthrenium Cation.

CHEMINFORM, Issue 45 2005
2-Vinyl Shift in the Persistent Carbocation., First Example for the
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Radical Addition to "Cation Pool".

CHEMINFORM, Issue 41 2005
Reverse Process of Radical Cation Fragmentation.
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

ChemInform Abstract: On the Bonding Nature of the N5+ (=N(N2)2+) Cation and Related Species N(CO)x+, N(NH3)x+, and NRx+, x = 1, 2 and R: He, Ne, Ar, Kr.

CHEMINFORM, Issue 28 2002
Do We Really Need the Resonance Concept?
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

ChemInform Abstract: Gas-Phase Chemistry of Bare V+ Cation with Oxygen and Water at Room Temperature: Formation and Hydration of Vanadium Oxide Cations.

CHEMINFORM, Issue 33 2001
Gregory K. Koyanagi
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

ChemInform Abstract: Ag(P4)+2: The First Homoleptic Metal,Phosphorus Cation.

CHEMINFORM, Issue 32 2001
Ingo Krossing
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Towards a Molecular Understanding of Cation,Anion Interactions,Probing the Electronic Structure of Imidazolium Ionic Liquids by NMR Spectroscopy, X-ray Photoelectron Spectroscopy and Theoretical Calculations

CHEMISTRY - A EUROPEAN JOURNAL, Issue 30 2010
Till Cremer
Abstract Ten [C8C1Im]+ (1-methyl-3-octylimidazolium)-based ionic liquids with anions Cl,, Br,, I,, [NO3],, [BF4],, [TfO],, [PF6],, [Tf2N],, [Pf2N],, and [FAP], (TfO=trifluoromethylsulfonate, Tf2N=bis(trifluoromethylsulfonyl)imide, Pf2N=bis(pentafluoroethylsulfonyl)imide, FAP=tris(pentafluoroethyl)trifluorophosphate) and two [C8C1C1Im]+ (1,2-dimethyl-3-octylimidazolium)-based ionic liquids with anions Br, and [Tf2N], were investigated by using X-ray photoelectron spectroscopy (XPS), NMR spectroscopy and theoretical calculations. While 1H,NMR spectroscopy is found to probe very specifically the strongest hydrogen-bond interaction between the hydrogen attached to the C2 position and the anion, a comparative XPS study provides first direct experimental evidence for cation,anion charge-transfer phenomena in ionic liquids as a function of the ionic liquid's anion. These charge-transfer effects are found to be surprisingly similar for [C8C1Im]+ and [C8C1C1Im]+ salts of the same anion, which in combination with theoretical calculations leads to the conclusion that hydrogen bonding and charge transfer occur independently from each other, but are both more pronounced for small and more strongly coordinating anions, and are greatly reduced in the case of large and weakly coordinating anions. [source]

Dynamic Equilibria in Solvent-Mediated Anion, Cation and Ligand Exchange in Transition-Metal Coordination Polymers: Solid-State Transfer or Recrystallisation?

CHEMISTRY - A EUROPEAN JOURNAL, Issue 35 2009
Xianjin Cui
Abstract The solution properties of a series of transition-metal,ligand coordination polymers [ML(X)n], [M=AgI, ZnII, HgII and CdII; L=4,4,-bipyridine (4,4,-bipy), pyrazine (pyz), 3,4,-bipyridine (3,4,-bipy), 4-(10-(pyridin-4-yl)anthracen-9-yl)pyridine (anbp); X=NO3,, CH3COO,, CF3SO3,, Cl,, BF4,; n=1 or 2] in the presence of competing anions, metal cations and ligands have been investigated systematically. Providing that the solubility of the starting complex is sufficiently high, all the components of the coordination polymer, namely the anion, the cation and the ligand, can be exchanged on contact with a solution phase of a competing component. The solubility of coordination polymers is a key factor in the analysis of their reactivity and this solubility depends strongly on the physical properties of the solvent and on its ability to bind metal cations constituting the backbone of the coordination polymer. The degree of reversibility of these solvent-induced anion-exchange transformations is determined by the ratio of the solubility product constants for the starting and resultant complexes, which in turn depend upon the choice of solvent and the temperature. The extent of anion exchange is controlled effectively by the ratio of the concentrations of incoming ions to outgoing ions in the liquid phase and the solvation of various constituent components comprising the coordination polymer. These observations can be rationalised in terms of a dynamic equilibrium of ion exchange reactions coupled with Ostwald ripening of crystalline products. The single-crystal X-ray structures of [Ag(pyz)ClO4], (1), {[Ag(4,4,-bipy)(CF3SO3)],CH3CN}, (2), {[Ag(4,4,-bipy)(CH3CN)]ClO4, 0.5,CH3CN}, (3), metal-free anbp (4), [Ag(anbp)NO3(H2O)], (5), {[Cd(4,4,-bipy)2(H2O)2](NO3)2,4,H2O}, (6) and {[Zn(4,4,-bipy)SO4(H2O)3] ,2,H2O}, (7) are reported. [source]