bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mass spectra of organometallic compounds—VII; Organonitrogen derivatives of metal carbonyls
Authors: King R. B. 
Published: May 2005

AbstractThe positive‐ion mass spectra of the following organonitrogen derivatives of metal carbonyls are discussed: (i) The compounds NC5H4CH2Fe(CO)2C5H5, NC5H4CH2COMo(CO)2C5H5, NC5H4CH2W(CO)3C5H5, NC5H4CH2COMn(CO)4, C5H10NCH2CH2Fe(CO)2C5H5, (CH3)2NCH2CH2COFeCOC5H5 and (CH3)2NCH2CH2COMn(CO)4 obtained from metal carbonyl anions and haloalkylamines, (ii) The isocyanate derivative C5H5Mo(CO)3CH2NCO; (iii) The arylazomolybdenum derivatives RN2Mo(CO)2C5H5 (R  phenyl, p‐tolyl, or p‐anisyl); (iv) The compound (C6H5N)2COFe2(CO)6 obtained from Fe3(CO)12 and phenyl isocyanate; (v) The N,N,N′,N′‐tetramethylethylenediamine complex (CH3)2NCH2CH2N(CH3)2W(CO)4. Further examples of eliminations of hydrogen, CO, and C2H2 fragments were noted. In addition evidence for the following more unusual processes was obtained: (i) Elimination of HCN fragments from the ions [NC5H4CH2MC5H5]+ to give the ions [(C5H5)2M]+ (M  Fe, Mo and W); (ii) Conversion of C5H5Mo(CO)3CH2NCO to C5H5Mo(CO)2CH2NCO within the mass spectrometer; (iii) Elimination of N2 from [RN2MoC5H5]+ to give [RMoC5H5]+; (iv) Novel eliminations of HNCO, FeNCO, and C6H5NC fragments in the mass spectrum of (C6H5N)2COFe2(CO)6; (v) Facile dehydrogenation of the N,N,N′,‐N′‐tetramethylethylenediamine ligand in the complex (CH3)2NCH2CH2N(CH3)2W(CO)4.
Massenspektrometrie herausgegeben von Hermann Kienitz, verfaßt von Fritz Aulinger, Gerhard Franke, Karleugen Habfast, Hermann Kienitz und Gerhard Spiteller. Verlag Chemie, Weinheim/Bergstraße, 1968. 883 Seiten mit 342 Abbildungen und 52 Tabellen im Text und einem Tabellenteil. Ganzleinen DM 195
Authors: Grützmacher H.‐Fr. 
Published: May 2005

AbstractStructure elucidation of organic compounds is only one of the applications of mass spectrometry to chemistry. Important subjects are also mass spectrometric quantitative analysis of mixtures of inorganic and of organic compounds, determination of isotopes and related problems. In ‘Massenspektrometrie’, edited by H. Kienitz, all these applications are discussed together with an excellent introduction to the function of mass spectrometers and the techniques of measurement. This book contains a lot of information and stimulation for mass spectroscopists and chemists, and is especially recomended for use in analytical laboratories.
Fragmentation of organic compounds on electron‐impact—V: 1,1‐Dichlorocyclopropanes
Authors: Weinberg D. S. , Stafford C. , Scoggins M. W. 
Published: May 2005

AbstractThe mass spectral fragmentation reactions of twenty‐one 1,1‐dichlorocyclopropanes prepared from various isomeric octenes are discussed. The most characteristic reaction may be represented as follows:
magnified imageThe importance of this fragmentation and the distribution of the positive charge between the species produced is a function of the degree of branching in the molecule. The more highly branched isomers produce less characteristic fragmentation patterns.The identification of isomeric octenes from the fragmentation patterns of the corresponding 1,1‐dichlorocyclopropanes is discussed.
Substituent effects in the fragmentation reactions of acetanilides and phenyl acetates
Authors: Shapiro Robert H. , Tomer Kenneth B. 
Published: May 2005

AbstractThe mass spectra of a group of m‐ and p‐substituted acetanilides were measured to determine the effect of the substituents, if any, on the rate of C2H2O expulsion (rearrangement) vs. the rate of [CH3CO]+ formation (simple cleavage). Our results agree with observations of others in that substituents which raise the ionization potential of the aromatic ring appear to localize, on the average, less charge density on this locus, and conversely. The atomic composition of the substituent, however, irrespective of its position, seems to determine the relative rates of the competing reaction. Although in several cases Zm/Zp values were close to unity, rearrangement of isomeric molecular ions to a common species is shown not to occur.
Electron‐impact studies—XLVII: The mass spectra of 2‐aryl‐1,3‐dithianes and ‐1,3‐dithiolanes
Authors: Bowie J. H. , White P. Y. 
Published: May 2005

AbstractThe fragmentation patterns in the spectra of 2‐aryl‐1,3‐dithianes and ‐1,3‐dithiolanes have been elucidated by deuterium labelling studies. Ortho effects are observed in the spectra of 2(o‐alkoxyphenyl)‐1,3‐dithianes. The molecular ions of the 1,3‐dithianes eliminate S2H· and metastable kpeaks substantiate these eliminations. The hydrogen involved in this elimination randomises (C‐4, 5 and 6) Prior to elimination in the spectrum of 2‐phenyl‐1,3‐dithiane, but originates mainly from C‐5 in that of the bis propane‐1,3‐dithioacetal of terephthaldehyde.
Mass spectra of organometallic compounds—IX: Compounds with metal‐metal bonds
Authors: King R. B. 
Published: May 2005

AbstractThe mass spectra of the following compounds have been investigated: (i) The organotin derivatives (CH3)3SnMo(CO)3C5H5 and (CH3)3SnNCW(CO)5; (ii) The mercury derivatives Hg[Mn(CO)5]2, Hg[Co(CO)4]2, Hg[Mo(CO)3C5H5]2 and ClHgMo(CO)3C5H5; (iii) The polynuclear cyclopentadienyl metal derivatives [C5H5Ru(CO)2]2, [C5H5Cr(CO)3]2, [C5H5Cr(NO)2]2 and [C5H5Fe‐CO]4; (iv) The trinuclear cobalt carbonyl derivatives YCCo3(CO)9 (Y = Cl and CH3); (v) The binuclear triene‐iron carbonyl derivatives C4H4Fe2(CO)6 and C8H10Fe2(CO)6. The mass spectra of the trimethyltin derivatives exhibited stepwise loss of methyl groups as well as of carbonyl groups. The mass spectra of the mercury derivatives exhibited the facile loss of mercury. The mass spectrum of [C5H5Cr(CO)3]2 indicated a very weak chromium‐chromium bond since it exhibited no ion containing two chromium atoms. The mass spectrum of the nitrosyl derivative [C5H5Cr(NO)2]2 exhibited the stepwise loss of its four nitrosyl groups. The mass spectrum of [C5H5FeCO]4 was rather complex and exhibited a variety of unusual processes including eliminations of neutral Fe and C5H5Fe fragments. Unusual ions observed in the mass spectrum of CH3CCo3(CO)9 include the bare polymetallic ions [Con]+ (n = 3 and 2). Many examples of the elimination of neutral CO, C2H2 and H2 fragments were noted in this work.
Electron‐impact studies—L: Skeletal‐rearrangement fragments in the mass spectra of diphenylpyrazoles and ‐isoxazoles
Authors: Simons B. K. , Kallury R. K. M. R. , Bowie J. H. 
Published: May 2005

AbstractThe mass spectra of all diphenylpyrazoles and ‐isoxazoles contain rearrangement peaks at m/e 165 [C13H9]+. In addition, the spectra of 3,5‐diphenylisoxazoles contain peaks at m/e 180 [C13H10N]+, which are produced by specific phenyl migrations. The mechanisms of both rearrangement processes have been studied by deuterium labelling.
The mass spectra of amino‐acid and peptide derivatives—III:. A comparison of the utility of various N‐protecting groups
Authors: Aplin R. T. , Eland I. , Jones J. H. 
Published: May 2005

AbstractComparison of the acetyl‐, trifluoroacetyl‐, benzyloxycarbonyl‐, methoxycarbonyl‐, ethoxycarbonyl, methylaminocarbonyl, phenylaminocarbonyl‐, phthanoyl‐, and stearoyl‐derivatives of glycylleucylphenylalanine methyl ester has shown that acetyl derivative is the most volatile. The relative abundances of the sequence ions in the mass spectra od these compounds have been determined and compared: the acetyl derivative provides the best combination of volatility and abundance of sequence ions. Evidence is presented to show that the use of acid‐catalysed esterification procedure for the chemical modification of peptides prior to mas spectrometric investigation can lead to degraded derivatives.
Massenspektrometrische Untersuchungen an Heterocyclen—IV: Zur Wasserstoffabspaltung aus Xanthen und Thioxanthen
Authors: Heiss J. , Zeller K.‐P. 
Published: May 2005

AbstractDie struktur der [M — 1]‐Ionen von Thioxanthen (I) und Xanthen (II) wird mit Hilfe der 9,9‐Dideuteroderivate (Ia und IIa) untersucht. Das Auftreten eines [M — 1]‐Ions auch bei Ia und IIa zeigt, daß neben einer einfachen Abspaltungsreaktion eine Umlagerung zu einem Troppyliumkation beteilligt ist. Eine wietere derartige Umlagerungsreaktion tritt auch bei der Fragmentierung von Thioxanthen‐S,S‐dioxid (III) auf.
Electron‐impact studies of organometallic molecules—XI:. Some polyfluoroaromatic derivatives of ferrocene
Authors: Bruce M. I. 
Published: May 2005

AbstractThe mass spectra of eight ferrocene derivatives containing C6F5, C6F5CO, C6F5CH2 or p‐CH3OC6F4 groups attached to one or both cyclopentadienyl rings are described and discussed. In addition to features normally found in the mass spectra of ferrocene compounds, the migration of fluorine to the iron atom leads to the formation of ions such as [C5H4COFeF]+. The elimination of neutral FeF2 or C5H5FeF molecules is also found.
The mass spectra of aluminum isopropoxide
Authors: Daasch Lester W. , Fales H. M. 
Published: May 2005

AbstractThe mass spectra of aluminum isopropoxide show that polymers, [Al(OC3H7)3]x where x = 1 to 7, can be present in the vapor and are, therefore, probably present in the bulk sample. The polymeric composition of the vapor depends on the previous history of the sample. Exact mass measurements on many of the ions along with data on a number of metastable peaks support the proposed fragmentation mechanisms. Loss of 102 mass units between intense peaks in the mass range above 500 a.m.u. leads to the suggestion that the higher polymers may be used as high mass marking substances.
Mass spectrometry in structural and stereochemical problems—CLXXVIII: The electron‐impact promoted fragmentation of 1,2‐cyclohexene oxide
Authors: Strong M. Karen , Brown Peter , Djerassi Carl 
Published: May 2005

AbstractThe mass spectra of 1,2‐cyclohexene oxide and three deuterium labeled analogs are discussed and mechanistic rationalizations are given for the major fragmentation processes observed. Multiple mechanisms are required to explain the indicated peak shifts in the labeled analogs for many of these ions, thus demonstrating again the care that needs to be exercised in the interpretation of the mass spectra of relatively simple molecules.
The mass spectra of cinnolines and their N‐oxides
Authors: Palmer M. H. , Russell E. R. R. , Wolstenholme W. A. 
Published: May 2005

AbstractThe mass spectra of cinnoline and various alkyl derivatives, and their 1‐ and 2‐mono‐oxides and 1,2‐dioxides and a quaternary salt have been investigated. The spectra are interpreted in the light of experiments with deutero and 15N labelled derivatives whose syntheses are described. The major fragmentation path for cinnoline is loss of nitrogen molecule while that for its homologues is loss of nitrogen plus a hydrogen atom in some instances. Various initial fragmentations occur with the N‐oxides, and deoxygenation appears to be the dominant process; in both 4‐methylcinnoline 1‐oxide and 1,2‐dioxide an important path is formation of a 3‐methyl‐anthranil cation by loss of HCN and HCNO respectively.
Electron‐impact fragmentation of the bicyclo[4.1.0]heptane‐2‐one system: Correlations with photochemistry
Authors: Fenselau Catherine , Shaffer G. W. , Dauben W. G. 
Published: May 2005

AbstractThe low resolution and complete high resolution mass spectra of a series of methyl and deuterium substituted bicyclo[4.1.0]heptane‐2‐one derivatives have been measured. An attempt has been made to test the operation of a fragmentation process analogous to the known photochemical rearrangement, and to determine if the substitution effects critical to the photorearrangement also influence the electron‐impact process. The fragmentation pattern of these conjugated cyclopropyl ketones is detailed and the influence of the cyclopropyl ring is discussed. It is suggested that electron‐impact‐induced rearrangements which are analogous to photochemical transformations will be relatively low energy processes and will remain prominent at low ionizing voltages.
Electron‐impact fragmentation of some secondary aliphatic nitramines. Migration of the nitro group in heterocyclic nitramines
Authors: Bulusu Suryanarayana , Axenrod T. , Milne G. W. A. 
Published: May 2005

AbstractThe mass spectra of a series of nitramines, including the explosives RDX and HMX, are reported. The nature of the major fragment ions is established by labeling with 15N or13C and by high resolution mass spectrometry. Electron‐impact‐induced fragmentation pathways including the migration of the nitro group in the heterocyclic nitramines, RDX and HMX, are postulated.
Zum Mechanismus Massenspektrometrischer Fragmentierungsreaktionen—IV: Zur Bildung von Phenonium‐Ionen bei der Elektronenstoß‐Fragmentierung von ß‐Phenyläthylbromiden
Authors: Grützmacher Hans‐Friedrich 
Published: May 2005

AbstractDie von N. M. M. Nibbering et al.3 aufgrund von Deuteriummarkierungen nachgweisene scheinbar gleichartige Bindung aller 9 H‐Atome in [C8H9]+‐Ionen, die durch Br‐Abspaltung aus β‐Phenyläthylbromid im Massenspektrometer entstehen, konnte bestätigt werden. Dieser Befund ist durch eine cyclooctatrienyl‐Struktur (a) erklärt worden. Ein Vergleich der Bildungsenthalpien von [C8H9]+‐Ionen verschiedenen Ursprungs beweist jedoch, daß dies für die aus ß‐Phenyläthylbromid im Grundzustand entstehenden [C8H9]+‐Ionen nicht zutrifft. R. H. shapiro et al.4 leiten aus dem Einfulß von substituenten am Phenylkern ovn ß‐Phenyläthylbromid auf die Intensität von [M  Br]+‐Ionen eine Phenonium‐Struktur (c) für die [C8H9]+‐Ionen ab. Der substituenteneffekt auf die Intensitäten und AP der [M  CH2Br]+‐Ionen substituierter ß‐Phenyläthylbromide ist jedoch deutlich anderer Art und läßt sich viel besser mit einer ‘Klassischen’ Struktur der [C8H9]+‐Ionen vereinbaren. Für diese Struktur spricht auch ein Vergleich der IP und AP der [M  Br]+‐Ionen von Benzyl‐, ß‐Phenyläthyl‐ und γ‐Phenylpropylbromid.
Massenspektrometrische Untersuchungen an Heterocyclen—V Fragmentierungsverhalten Einiger Purine
Authors: Heiss Jürgen , Zeller Klaus‐Peter , Voelter Wolfgang 
Published: May 2005

AbstractDie Massenspektren von 9 Purinen werden diskutiert. Purine vom Xanthintyp spalten HNCO und anschließend CO, während 3‐Methylhypoxanthin HCN und CO verliert. Im Fall des 3‐Methylxanthins entsteht os ein Ion, dessen Stabilisierung durch Umlagerung diskutiert. wird. Das Fragmentierungsverhalten von 3‐Methyl‐2‐thioxanthin und 3‐Methyl‐thiohypoxanthin weicht von dem der entsprechenden Sauerstoffanaloga ab. 6‐Methyl‐mercaptopurin und 6‐Methoxypurin eliminieren HCS· bzw. HCO·. Für diese Reaktion wird ein Mechanismus vorgeschlagen.
Massenspektren von Metallkomplexen des 2‐n‐Butyl‐8‐Hydroxychinolins
Authors: Budzikiewicz H. , Plöger E. 
Published: May 2005

AbstractDas Fragmentierungsmuster der Metallkomplexe des 2‐Butyl‐8hydroxychinolins hängt im wesentlichen davon ab, ob das Metall‐Ion unter Aufnahme eines Elektrons in eine stabile einwertige Form übergehen kann oder nicht. Im ersten Fall entsteht das Hauptfragment durch Verlust eines Moleküls 2‐n‐Butyl‐8hydroxychinolin, im zweiten durch Abspaltung eines Äthyl radikals.
Mass spectrometry in structural and stereochemical problems—CLXXXVII A study of skeletal rearrangements in chromans by combined 13C and deuterium labeling
Authors: Trudell J. R. , Woodgate S. D. Sample , Djerassi Carl 
Published: May 2005

AbstractChroman (I), 2,2‐dimethylchroman (II), flavan (III) and 2,2‐diphenylchroman (IV) were labeled with 13C or deuterium at every position of importance. The mass spectra of these labeled compounds make possible a detailed interpretation of some very complex carbon skeleton rearrangements. The combination of deuterium and 13C‐labeling revealed that loss of CH3, C2H5 and C7H7 fragments from chroman (I), 2,2‐dimethylchroman (II) and 2,2‐diphenylchroman (IV) respectively, occurs by multiple pathways involving aryl or alkyl migrations with little hydrogen randomization prior to fragmentation. Although ejection of C7H7 from flavan (III) occurs to a small extent by a route similar to those mentioned above, its [M  C7H7] fragment can also be formed by a pathway involving no phenyl migration but extensive hydrogen scrambling. The validity of the schemes proposed on the basis of the 13C labeling data was checked by using them to predict the spectra of the deuterium labeled compounds.
Charge participation in the fragmentation of functionalized steroids
Authors: Vetter W. , Meister W. , Richter W. J. 
Published: May 2005

AbstractA series of steroidal model compounds specifically designed to allow maximal as well as minimal charge localization at certain functional groups was subjected to mass spectrometric analysis. The results indicate that electron deficiency at the potentially reactive site is a prequisite for any fragmentation reaction to occur to an appreciable extent. The amount of charge density required at such a site seems to vary substantially for different types of fragmentation processes.
The mass spectra of acetylenic ketones and their secondary amine adducts
Authors: Aplin R. T. , Mestres R. 
Published: May 2005

AbstractThe mass spectra of a number of alkyl and aryl acetylenic ketones of the type RCO·CC·CC·R′ have been examined. All the spectra exhibit molecular ions together with the expected intense fragments arising from cleavage α‐to the carbonyl group. The most striking feature of the ketone spectra is the loss of CO from the molecular ion. This process dominates the spectra of the aryl ketones, the spectra below [M – 28]+˙. being virtually identical to those of the corresponding phenylacetylenes. The spectra of the piperidene and/or morpholine adducts of the alkyl ketones are very similar to those of the parent ketone whereas those of the aryl ketones are dominated by the loss HO˙ from the molecular ion. Deuterium labelling has established the site of the hydrogen involved as being the carbons α‐ to the nitrogen of the heterocyclic ring.
Aldehyde and ketone spectra from bisulfite adducts
Authors: Fenselau Catherine , Young John L. , Landis William R. 
Published: May 2005

AbstractThe use of bisulfite derivatives of liquid aldehydes and cyclic ketones is reported to facilitate sample handling in mass spectral analysis of these compounds. The carbonyl compounds can be regenerated from their sulfinate derivatives in the direct probe. Precautions must be taken to avoid back exchange of enolizable deuterium atoms in labeled carbonyl compounds.
Mass spectrometry of the 11H‐dibenzo[c,f][1,2]‐diazepine system
Authors: Popp F. D. , Dubois R. J. , Potts K. T. , Brugel E. 
Published: May 2005

AbstractThe mass spectra of 3,8‐dichloro‐11H‐dibenzo[c,f] [1,2]diazepine, the corresponding diazepin‐11‐01 and diazepin‐11‐one and their dihydro and N‐oxide derivatives have been recorded. The most important fragmentation of the molecular ions of all diazepines studied was an initial loss of m/e 28, with further fragmentation depending on the 11‐substituent. No general pathway was observed for the corresponding N‐oxides and dihydro compounds.
Mass spectra of organometallic compounds–XI: Pyrrolyl, indenyl and fluorenyl derivatives of manganese carbonyl
Authors: King R. B. , Efraty A. 
Published: May 2005

AbstractThe positive ion mass spectra of the π‐pyrrolyl derivatives C4H4NMn(CO)2L (L = (C6H5)3E or CO; E = P, As, or Sb), the π‐indenyl derivatives C9H7Mn(CO)2L (L = (C6H5)3E or CO; E = P, As, or Sb) and the π‐fluorenyl derivatives C13H9Mn(CO)2L (L = (C6H5)3P or CO) have been investigated. The relative tendencies of ions of the type [QMnE(C6H5)3]+ (Q = π‐pyrrolyl, π‐indenyl, or π‐fluorenyl; E = P, As, or Sb) to fragment by losses of the Q ring system and the (C6H5)3E ligand are compared. Phenyl transfers from phosphorus, arsenic, or antimony to manganese to form relatively high abundances of [C6H5Mn]+ are also observed. Other processes typical of metal carbonyl derivatives (CO losses), aromatic derivatives (C2H2 eliminations) and (C6H5)3E derivatives (phenyl losses, conversion of [(C6H5)3E]+ directly to [C6H5E]+, and formation of [C12H8E]+ 9‐heterofluorenyl ions) are observed in these mass spectra and are supported in many cases by the presence of appropriate metastable ions.
Mass spectral studies of some β‐diketones and their beryllium complexes
Authors: Patel Kantilal S. , Rinehart Kenneth L. , Bailar John C. 
Published: May 2005

AbstractDetailed comparison of the fragmentation behavior of a series of beryllium β‐diketonates with that of the corresponding series of β‐diketones reveals a number of striking differences. A‐typical fragmentations are observed for diketones and diketonates with trifluoromethyl and α‐phenyl substituents.
The mass spectra of 2,4,7‐trihydroxypteridines and their trimethylsilyl derivatives
Authors: Haug Pat , Urushibara Toshiyuki 
Published: May 2005

AbstractThe mass spectra of a series of 2,4,7‐trihydroxypteridines and their trimethylsilyl derivatives have been determined. Fragmentation mechanisms are supported by high resolution, deuterium labeling and metastables.
Mass spectrometry of homoadamantane derivatives
Authors: Yurchenko A. G. , Stepanov F. N. , Isaeva S. S. , Zolotarev B. M. , Kadentsev V. I. , Chizhov O. S. 
Published: May 2005

AbstractHomoadamantane derivatives can be divided into two groups according to their mass spectra. To the first group belong compounds with electron attracting substituents (COOH, CI, COOCH3, Br); compounds with electron releasing substituents (OCH3, OH, NH3, NHCOCH3) constitute the second group.The most characteristic feature of the first group compounds is the splitting off of the substituent. The hydrocarbon fragment [C11H17]+ thus formed then loses olefin molecules with the formation of corresponding ionic species C11−nH17−2n. The 3‐substituted compounds of this group undergo thermal Wagner‐Meerwein type rearrangements into adamantane derivatives, resulting in the [C10H15]+ (m/e 135) ion formation; this is the main difference between 1‐ and 3‐substituted homoadamantanes.The series of [CnH2n−6X]+ ions (where X = OCH3, OH, NH2, NHCOCH3, n = 6 to 10) are characteristic of the mass spectra of the second group compounds, the ion [C6H6X]+, [M  C5H11]+ being the most abundant. The intensity ratio of [M  C5H11]+ to [M  C4H9]+ ions is 10:1 for 1‐substituted and 3:1 for 3‐substituted compounds of this group, allowing the location of the substituent. Some individual features of the spectra are also reported.
Mass spectrometry of onium salts—I. Studies on anilinium oxides
Authors: Undheim Kjell , Hvistendahl Georg 
Published: May 2005

AbstractThe mass spectra of the three isomeric trimethylanilinium oxides and their methyl‐d3 analogues show that the m‐ and p‐ isomers undergo intermolecular trans‐O‐alkylation before evaporation. In the o‐isomer, only 10% transalkylated product is observed and there is strong evidence that most of this isomer evaporates without undergoing structural changes. By indirect introduction, however, the o‐isomer showed only transalkylated product.The most important fragmentation patterns on electron‐impact are α‐cleavage on the N‐methyl carbon or expulsion of the O‐substituent with formation of a quinoid structure. The latter dominates for the o‐ and p‐methyl ethers while the former is the most important pathway for the m‐isomer and for the corresponding phenols. Lower fragments are of modest intensity.