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Although the deleterious effects of ozone on the human respiratory system are well-known, many of the precise chemical mechanisms that both cause damage and afford protection in the pulmonary epithelial lining fluid are poorly understood. As a key first step to elucidating the intrinsic reactivity of ozone with proteins, its reactions with deprotonated cysteine [Cys−H]− are examined in the gas phase. Reaction proceeds at near the collision limit to give a rich set of products including 1) sequential oxygen atom abstraction reactions to yield cysteine sulfenate, sulfinate and sulfonate anions, and significantly 2) sulfenate radical anions formed by ejection of a hydroperoxy radical. The free-radical pathway occurs only when both thiol and carboxylate moieties are available, implicating electron-transfer as a key step in this reaction. This novel and facile reaction is also observed in small cys-containing peptides indicating a possible role for this chemistry in protein ozonolysis. [ABSTRACT FROM AUTHOR]

A combination of gas-phase ion-molecule reaction experiments and theoretical kinetic modeling is used to examine how a salt can influence the kinetic basicity of organometallates reacting with water. [HC−CLiCl]− reacts with water more rapidly than [HC−CMgCl2]−, consistent with the higher reactivity of organolithium versus organomagnesium reagents. Addition of LiCl to [HC−CLiCl]− or [HC−CMgCl2]− enhances their reactivity towards water by a factor of about 2, while addition of MgCl2 to [HC−CMgCl2]− enhances its reactivity by a factor of about 4. Ab initio calculations coupled with master equation/RRKM theory kinetic modeling show that these reactions proceed via a mechanism involving formation of a water adduct followed by rearrangement, proton transfer, and acetylene elimination as either discrete or concerted steps. Both the energy and entropy requirements for these elementary steps need to be considered in order to explain the observed kinetics. [ABSTRACT FROM AUTHOR]

A combination of gas-phase ion-molecule reaction experiments and theoretical kinetic modeling is used to examine how a salt can influence the kinetic basicity of organometallates reacting with water. [HC−CLiCl]− reacts with water more rapidly than [HC−CMgCl2]−, consistent with the higher reactivity of organolithium versus organomagnesium reagents. Addition of LiCl to [HC−CLiCl]− or [HC−CMgCl2]− enhances their reactivity towards water by a factor of about 2, while addition of MgCl2 to [HC−CMgCl2]− enhances its reactivity by a factor of about 4. Ab initio calculations coupled with master equation/RRKM theory kinetic modeling show that these reactions proceed via a mechanism involving formation of a water adduct followed by rearrangement, proton transfer, and acetylene elimination as either discrete or concerted steps. Both the energy and entropy requirements for these elementary steps need to be considered in order to explain the observed kinetics. [ABSTRACT FROM AUTHOR]

Eine massenspektrometrische Analyse zeigt, dass die Umsetzung von Silbersalzen mit Natriumborhydrid in Gegenwart eines Diphosphanliganden nicht zu reinen Silber ‐ Nanoclusterkationen führt, sondern zu neuartigen Silberhydrid ‐ Nanoclusterkationen. Diese Entdeckung beflügelte die Flüssigphasensynthese, Isolierung und Charakterisierung von [Ag3{(Ph2P)2CH2}3(μ3 ‐ H)(μ3 ‐ Cl)]BF4 ⋅0.5 CHCl3. [ABSTRACT FROM AUTHOR]

Eine massenspektrometrische Analyse zeigt, dass die Umsetzung von Silbersalzen mit Natriumborhydrid in Gegenwart eines Diphosphanliganden nicht zu reinen Silber ‐ Nanoclusterkationen führt, sondern zu neuartigen Silberhydrid ‐ Nanoclusterkationen. Diese Entdeckung beflügelte die Flüssigphasensynthese, Isolierung und Charakterisierung von [Ag3{(Ph2P)2CH2}3(μ3 ‐ H)(μ3 ‐ Cl)]BF4 ⋅0.5 CHCl3. [ABSTRACT FROM AUTHOR]

A combination of gas ‐ phase ion – molecule reaction experiments and theoretical kinetic modeling is used to examine how a salt can influence the kinetic basicity of organometallates reacting with water. [HCCLiCl]− reacts with water more rapidly than [HCCMgCl2]−, consistent with the higher reactivity of organolithium versus organomagnesium reagents. Addition of LiCl to [HCCLiCl]− or [HCCMgCl2]− enhances their reactivity towards water by a factor of about 2, while addition of MgCl2 to [HCCMgCl2]− enhances its reactivity by a factor of about 4. Ab initio calculations coupled with master equation/RRKM theory kinetic modeling show that these reactions proceed via a mechanism involving formation of a water adduct followed by rearrangement, proton transfer, and acetylene elimination as either discrete or concerted steps. Both the energy and entropy requirements for these elementary steps need to be considered in order to explain the observed kinetics. Salzeffekte: Wie beeinflussen bestimmte Salze die kinetische Basizität von mit Wasser reagierenden Organometallaten? Die Zugabe von LiCl zu [HCCLiCl]− oder [HCCMgCl2]− beschleunigt die Reaktion mit Wasser ungefähr um den Faktor zwei, und die Zugabe von MgCl2 zu [HCCMgCl2]− um den Faktor vier (siehe Bild). Der Mechanismus der Hydratisierung wird theoretisch untersucht. [ABSTRACT FROM AUTHOR]

Der Massenspektrometrie ‐ Mann rettet den Tag! Bei der Reise von seinem Heimatplaneten Gasphase nutzte er seine ESI ‐ MS ‐ Kräfte, um G. N. Khairallah, P. S. Donnelly, R. A. J. O'Hair et al. mit essenziellen Informationen für die Zuschrift auf S. 8549 ff. zu versorgen. Die Kräfte des MS ‐ Manns enthüllten die Bildung eines neuartigen Silberhydrid ‐ Nanoclusterkations in Silbersalzen, die mit Natriumborhydrid in Gegenwart eines Bis(phosphanyl) ‐ Liganden reduziert wurden, und wiesen den Weg zu der Synthese von [Ag3{(Ph2P)2CH2}3(μ3 ‐ H)(μ3 ‐ Cl)]BF4⋅0.5 CHCl3 in kondensierter Phase, seiner Isolierung und Charakterisierung. [ABSTRACT FROM AUTHOR]