A Mass‐Spectrometric Investigation of C_xNO₂ (x=1, 2) Ions and Neutrals

Abstract

4 LThe isomeric [C2,N,02]+ ions OCNCO+, OCCNO+, and NCCO, have been generated and structurally characterized on the basis of their collisional activation, charge reversal, and neutralization-reionization mass spectra. The open-shell neutrals formed in the neutralization step undergo facile unimolecular decomposition. A recovery signal is obtained only for OCCNO.1. --In recent years, we have used the technique of neutralization-reionization mass spectrometry ['] to characterize cumulenes of theoretical and cosmochemical interest". Much of this work has concentrated on sulfides, oxides, and nitrides of carbon. A logical extension of this work is a study of cumulenes containing multiple heteroatoms. However, the more heteroatoms the molecule of interest contains, the more difficult it becomes to distinguish between isomeric species. In such instances it is desirable to generate and study several structural isomers.Here we report that three different [C2,N,02]+ ions may be clearly distinguished by using collisional mass-spectrometry techniques. Surprisingly, the smaller [C,N,02] + system is less clear. Results and DiscussionA number of compounds give rise to [C2,N,02]+ ions. For instance, the cyclic amides succinimide (1) and parabanic acid (2) as well as azoformamide (3) and ethyl chlo-

Triuret as a potential hypokalemic agent: Structure characterization of triuret and triuret–alkali metal adducts by mass spectrometric techniques

“…Detection of a fragment ion [OCNCO] + ( m/z 70) that failed to retain a single hydrogen atom, was surprising (Scheme 2). Structure and reactivity of this ion have been repeatedly investigated in the past [45–52]. Our CID MS/MS experiments of the mass-selected ion with m/z 70 produced following the fragmentation of protonated triuret revealed that its structure is "linear" as shown on Scheme 2 and its MS/MS spectrum is consistent with that reported earlier for a similar structure [47, 48].…”

Isolation and Structure of the OCNCO+ Ion

“…[1] OCNCO has so far only been observed in the mass spectrometer as a decomposition product of various molecules generated by electron impact ionization. [2] An ion generated as such, which was initally assumed to be linear, reacts in the mass spectrometer with pyridine forming 1:1 and 1:2 adducts, in which the OCNCO moiety is now assumed to be bent. [3] The starting point for our synthesis was the idea to generate the OCNCO ion in the form of a salt by Cl À or F À abstraction from ClÀCOÀNCO and FÀCOÀNCO with strong Lewis acids.…”

“…[7] Experimental Section FÀCOÀNCO was prepared in 70 % yield from ClÀCOÀNCO by halogen exchange with an excess of SF 3 /SbCl 5 at 75 8C. The product must be removed immediately from the reaction vessel in order to avoid decomposition into COF 2 and OC(NCO) 2 . The latter polymerizes under these conditions.…”

Isolierung und Struktur des OCNCO+-Ions

“…[1] OCNCO ist bisher nur im Massenspektrum als durch Elektronenstoûionisation erzeugtes Zerfallsprodukt verschiedener Moleküle nachgewiesen worden. [2] Ein so erzeugtes Ion, dem zunächst eine lineare Geometrie zugeschrieben wurde, reagiert im Massenspektrometer mit Pyridin zu 1:1-und 1:2-Adukten, für die nunmehr nichtlineare OCNCO-Geometrien angenommen werden. [3] Ausgangspunkt unserer Synthese war die Idee, durch Cl Àoder F À -Abstraktion von ClÀCOÀNCO und FÀCOÀNCO mit starken Lewis-Säuren Salze des OCNCO -Ions zu erhalten.…”

“…[1] Trotz der Bedeutung solcher Verbindungen für viele Katalyseprozesse, bei denen sie häufig viel höhere Aktivitäten als Übergangsmetallhydride aufweisen, sind die meisten dieser Verbindungen Ln III -Komplexe, die den Cyclopentadienylliganden oder dessen substituierte Analoga enthalten. Folgende Lanthanoidhydride mit zweiwertigen Metallzentren sind bekannt: Borhydridkomplexe des Typs [Ln{(m-H) 3 BH} 2 (CH 3 CN) n ] (Ln Yb, n 4; Ln Eu, n 2), [2] Trialkylboran-stabilisierte Hydride des Typs [Ln(Tp tBu,Me )-(HBEt 3 )(thf) n ] (Ln Sm, n 0; Ln Yb, n 1), [3] die Hydrid- [5].…”