The activation energy of the skeletal isomerization in the radical cations of toluene and cycloheptatriene by mass spectrometry of their 2-phenylethyl derivatives

Kuck D, Grützmacher H-F. The activation energy of the skeletal isomerization in the radical cations of toluene and cycloheptatriene by mass spectrometry of their 2-phenylethyl derivatives. Organic Mass Spectrometry. 1979;14(2):86-97

The formation and reactions of 9,10-phenanthryne and related arynes by pyrolytic reactions in the vapor phase

Grützmacher H-F, Straetmans U. The formation and reactions of 9,10-phenanthryne and related arynes by pyrolytic reactions in the vapor phase. Tetrahedron. 1980;36(6):807-813

Gas phase substitution of halobenzenes by methylamine and dimethylamine via radical cations

Thölmann D, Grützmacher H-F. Gas phase substitution of halobenzenes by methylamine and dimethylamine via radical cations. International Journal of Mass Spectrometry and Ion Processes. 1992;117(1-3):415-440.The reactions of the radical cations of the halobenzenes C6H5X.+ (X = Cl, Br, I), the isomeric dichlorobenzenes and the isomeric chloroiodobenzenes with CH3NH2 as well as the reactions of the radical cations CH3NH2.+ and (CH3)2NH.+ with the above neutral halobenzenes were studied by Fourier transform ion cyclotron resonance spectrometry. In all cases the substitution of a halogen substituent by R2NH+ (R = H, CH3) was observed besides charge exchange. The substitution of halobenzene radical cation by CH3NH2 is always fast (the reaction efficiency (eff(subst)) being greater than 28%) compared to the reaction with NH3 studied before, but exhibits principally the same dependence on the nature and position of the halogen substituent as the latter reaction. The substitution of neutral halobenzenes, where the ionization energy of the halobenzene is greater than the ionization energy of methylamine, by CH3NH2.+ is also fast (eff(subst) > 50%) and is not much influenced by the structure of the halobenzene. In contrast, the rate of substitution of all halobenzenes by (CH3)2NH.+ is small (eff(subst) < 14%), increases with the halogen lost in the series Cl < Br < I, and exhibits a distinct orientation effect for dihalobenzenes, the meta isomer being least reactive. These experimental results are discussed using thermochemical data from the literature and the curve crossing model of Shaik and Pross. The results are consistently rationalized for the reaction of ionized halobenzenes with neutral amines as well as the reaction of neutral halobenzenes with ionized amines by a mechanism involving addition to the aromatic system, rearrangement of the intermediate distonic ion to an ipso-substituted isomer, and dissociation of the intermediate by loss of halogen. However, the rate-determining step of this mechanism depends on the substrates involved, and this structural dependence of the reactions can be understood by the curve crossing model

Spontaneous fragmentations of protonated benzaldimines mediated by intermediate ion-neutral complexes

Grützmacher H-F, Zalfen U. Spontaneous fragmentations of protonated benzaldimines mediated by intermediate ion-neutral complexes. Organic Mass Spectrometry. 1990;25(6):323-328

Ion/molecule complexes as intermediates during the elimination of arenes from [beta]-arylethyl arenium ions

Bäther W, Grützmacher H-F. Ion/molecule complexes as intermediates during the elimination of arenes from [beta]-arylethyl arenium ions. International Journal of Mass Spectrometry and Ion Processes. 1985;64(2):193-212

Interannular proton exchange in protonated long-chain 1, [omega]-diphenylalkanes

Kuck D, Bäther W, Grützmacher H-F. Interannular proton exchange in protonated long-chain 1, [omega]-diphenylalkanes. International Journal of Mass Spectrometry and Ion Processes. 1985;67(1):75-91

Positional identification of fluorine in methyl per-O-acetyl-x-deoxy-x-fluoro-[alpha]- D-hexopyranosides by electron impact and chemical ionisation mass spectrometry

Kovácik V, Kovác P, Grützmacher H-F. Positional identification of fluorine in methyl per-O-acetyl-x-deoxy-x-fluoro-[alpha]- D-hexopyranosides by electron impact and chemical ionisation mass spectrometry. Carbohydrate Research. 1992;226(2):189-196.Fully acetylated methyl x-deoxy-x-fluoro-alpha-D-glucopyranosides have been studied using electron impact and ammonia chemical ionisation mass spectrometry. Mass analysed metastable ion kinetic energy spectroscopy (MIKE), collisional activation (CID), and accelerated voltage scanning have been used to evaluate complete fragmentation schemes. Characteristic differences in the fragmentation of positional isomers were noted on analysis of the spectra, and these make it possible to determine the location of fluorine in the molecules studied. Collisionally activated fragmentation of [M - OCH3]+ ions, produced by electron impact, provides an alternative method for localisation of the fluorine atoms. To the contrary, MIKE and CID spectra of [M + NH4]+ cluster ions produced by chemical ionisation did not afford such structural information

Remote fragmentations of protonated aromatic carbonyl compounds via internal reactions in intermediary ion-neutral complexes

Thielking G, Filges U, Grützmacher H-F. Remote fragmentations of protonated aromatic carbonyl compounds via internal reactions in intermediary ion-neutral complexes. Journal of the American Society for Mass Spectrometry. 1992;3(4):417-426.Protonated aromatic aldehydes and methyl ketones 1a-10a, carrying initially the proton at the carbonyl group, are prepared by electron impact-induced loss of a methyl radical from 1-arylethanols and 2-aryl-2-propanols, respectively. The aryl moiety of the ions corresponds to a benzene group, a naphthalene group, a phenanthrene group, a biphenyl group, and a terphenyl group, respectively, each substituted by a CH3OCH2 side-chain as remote from the acyl substituent as possible. The characteristic reactions of the metastable ions, studied by mass-analyzed ion kinetic energy spectrometry, are the elimination of methanol, the formation of CH3OCH2+ ions, and the elimination of an ester RCOOCH3 (R = H and CH3). The mechanisms of these fragmentations were studied by using D-labeled derivatives. Confirming earlier results, it is shown that the ester elimination, at least from the protonated aryl methyl ketones, has to proceed by an intermediate [acyl cation/arylmethyl methyl ether]-complex. The relative abundances of the elimination of methanol and of the ester decrease and increase, respectively, with the size of the aromatic system. Clearly, the fragmentation via intermediate ion-neutral complexes is favored for the larger ions. Furthermore, the acyl cation of these complexes can move unrestricted over quite large molecular distances to react with the remote CH3OCH2-side-chain, contrasting the restricted migration of a proton by 1,2-shifts ("ring walk") in these systems

Massenspektrometrischer Nachweis von Arzneimittelmetaboliten (Barbiturate, Noludar, Pyramidon) im Rahmen der forensischen Analyse

Arnold W, Grützmacher H-F. Massenspektrometrischer Nachweis von Arzneimittelmetaboliten (Barbiturate, Noludar, Pyramidon) im Rahmen der forensischen Analyse. Fresenius' Journal of Analytical Chemistry. 1969;247(3-4):179-188.Die massenspektrographische Identifizierung von aus biologischem Material isolierten Metabolitensubstanzen verschiedener Arzneimittel (Barbiturate, Noludar, Pyramidon) wird an Hand der einzelnen Massenspektren und ihrer daraus abgeleiteten Zerfallsschemata besprochen. In Zukunft wird die Massenspektrographie, vor allem kombiniert mit der Gas-Chromatographie, sicherlich mehr als bisher mit dazu beitragen, viele, häufig sehr differenzierte Probleme des Arzneimittelmetabolismus zu klären

INFLUENCE OF THE CHAIN-LENGTH ON THE MASS-SPECTROMETRIC FRAGMENTATION OF HIGHER 1, OMEGA-DIPHENYLALKANES

Kuck D, Grützmacher H-F. Der Einfluß der Kettenlänge auf die massenspektrometrische Fragmentierung höherer 1.[Omega]-Diphenylalkane. Zeitschrift für Naturforschung B, Journal of Chemical Sciences. 1979;34(12):1750-1764