Mass spectra of organometallic compounds—VIII. Some transition metal organometallic halide derivatives

The positive ion mass spectra of the transition metal organometallic halide derivatives C₅H₅M(CO)₃Cl(M ? Mo or W), C₇H₇W(CO)₂I, C₃H₅Fe(CO)₃I, [C₃H₅PdCl]₂, and [C₅H₅Mo(NO)I₂]₂ have been investigated. Further examples of the elimination of CO and C₂H₂ fragments were noted. In addition the following effects of particular interest were observed: (i) Evidence in the mass spectra of the chlorides for reactions with adventitious iodine and even bromine present in the mass spectrometer; (ii) Evidence for conversion of the compounds C₅H₅Mo(CO)₃X to the new halides [C₅H₅Mo(CO)X]₂ upon pyrolysis; (iii) Evidence for facile losses of the π-allyl group, the iodine atom, and methyl iodide in the mass spectrum of the π-allyl derivative C₃H₅Fe(CO)₃I; (iv) Evidence for loss of iodine upon introducing [C₅H₅Mo(NO)I₂]₂ into the mass spectrometer to give ions derived from [C₅H₅Mo(NO)I]₂.     

Mass spectra of organometallic compounds–XI: Pyrrolyl,indenyl and fluorenyl derivatives of manganese carbonyl

The 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 spectra of organometallic compounds—VII; Organonitrogen derivatives of metal carbonyls

The 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.     

Mass spectra of organometallic compounds—IX: Compounds with metal-metal bonds

The 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 [Co_n]⁺ (n = 3 and 2). Many examples of the elimination of neutral CO, C₂H₂ and H₂ fragments were noted in this work.     

Mass spectra of organometallic compounds: XIV—Some monometallic olefing manganese tricarbonyl derivatives

The metastable ion supported fragmentation process in the mass spectra of the cyclohexadienyl derivative C₆H₇Mn(CO)₃, the cycloheptadienyl derivative C₇H₉Mn(CO)₃, the 1,2,3,4,5-and 1,2,3,5,6-pentahaptocyclootadienyl derivatives C₈H₁₁Mn(CO)₃, the cyclooctatrienyl derivative C₈H₉Mn(CO)₃ and the substituted cyclopentadienyl derivative (CH₃)₂NCH₂C₅H₄Mn(CO)₃, are described. Losses of carbonyl groups, generally stepwise, from the molecular ions to give the corresponding [M – 3CO]⁺· ions are first observed. Further fragmentation of the carbonyl-free [M – 3CO]⁺· ions can involve a variety of processes such as the following: (a) elimination of a neutral manganese atom to give a hydrocarbon fragment; (b) elimination of a neutral hydrocarbon fragment to give an [MnH]⁺· ion; (c) dehydrogenation; (d) elimination of a 2-carbon C₂H₂ or C₂H₄ fragment; (e) elimination of a C₃H₄ or C₃H₆ fragment as a neutral species when it is bridging two carbon atoms bonded to manganese, as in C₈H₉Mn(CO)₃ and 1,2,3,4,5,h⁵-C₈H₁₁Mn(CO)₃, respectively. Fragmentation of the [M – 3CO]⁺· ion in (CH₃)₂NCH₂C₅H₄Mn(CO)₃ presents the following additional features: (a) elimination of C₆H₆ with a nitrogen shift from carbon to manganese; (b) elimination of a neutral dimethylamino fragment to give [C₆H₆Mn]⁺·, which then loses neutral C₆H₆, C₆H₅ or Mn fragments and thus is formulated tentatively as [(fulvene)Mn]⁺· or [C₆H₅MnH]⁺· rather than [(benzene)Mn]⁺·.     

The NMR spectra and conformations of cyclic compounds–III: The conformations of some pinane derivatives

The 220 MHz ¹H spectra of isoverbanone, nopinone and verbanone are reported. The spectra of the first two are completely assigned but that of verbanone only partially. The coupling constants obtained provide information about the conformation of these molecules. The isoverbanone molecule is almost Y shaped, but that of nopinone is between a Y shape and a half-chair conformation with the six membered ring bent away form the gem dimethyl groups. These conformations are consistent with the known steric interactions in these molecules.     

Mass spectrometry of hop compounds—II: Mass spectra of related oxygen heterocyclic compounds

Mass spectra have been determined of a number of phloroglucinol derivatives and closely-related compounds encountered in chemical studies of hop components. Initial fission involving acyl, alkyl or alkenyl side-chains gives predominantly even-electron ions which then fragment their oxygen heterocyclic rings by elimination of neutral molecules, whilst gem-dialkenyl centres show preference for loss of an alkenyl group. The fragment ions induced by electron-impact may be correlated to a useful extent with molecular structure.     

Mass spectra of organoboron compounds—II: The mass spectra of triphenylboroxine and its precursor phenylboronic acid

The mass spectrometric fragmentation pattern of phenylboronic acid has been determined and that of triphenylboroxine redetermined and extended, and the origin of some high abundance ions, previously unassigned, have been identified.     

Mass spectra of organoarsenic compounds—II: Electron-impact-induced fragmentation of 2-substituted-1,2,2-dioxarsenanes

The electron-impact-induced fragmentation of 2-substituted 1,3,2-dioxarsenanes has been studied. The main fragmentation modes have been determined with the use of high resolution mass measurements and by application of the metastable defocusing technique. The predominant fragmentation for the 2-alkyl-1,3,2-dioxarsenanes proceeds via the loss of the 2-substituent from the molecular ion. In the case of 2-phenyl-1,3,2-dioxarsenanes elimination of the phenyl group competes with the formation of a C₆H₅ As ion as well as loss of aldehyde from the molecular ions.     

Mass spectrometry of onium compounds—II. Carnitine and O-acyl derivatives

Carnitine and its O-acyl derivatives undergo two major pyrolytic reactions in the mass spectrometer. Firstly elimination of water from carnitine or acid from acylcarnitine takes place followed by intramolecular displacement and formation of crotonyl lactone and trimethylamine. Secondly intramolecular displacement occurs with formation of a substituted γ-lactone and trimethylamine. For the lower acid derivatives only the elimination pathway is important. For carnitine and higher derivatives both processes are important. The electron induced fragmentations of the major pyrolysis products are relatively simple. The most important pathways for the major components are discussed. The pyrolytic composition and mode of fragmentation are characteristic and can be used for identification purposes.     

Mass spectrometry of onium compounds—XVII: Anilinium carboxylates. orthoeffect in anthranilic acid derivatives

The N,N,N-trimethylanilinium carboxylates are transmethylated to the isomeric esters before evaporation in the mass spectrometer. Pyroltic reactions and electron-impact fragmentations are elucidated by means of deuterio analogues. The orthoisomer behaves anomalously in that initial expulsion of a methyl radical is important. Deuteration has shown this reaction to take place along two distinct routes, either from the nitrogen or from the ester.     

Mass spectra of organoarsenic compounds—I: Electron-impact-induced fragmentations of esters of arsenious and thioarsenious acid

The mass spectra of a series of esters of arsenious and thioarsenious acid have been studied, together with that of diethyl methylarsonite. The main fragmentation pathways have been determined with the use of high resolution mass measurements and application of the metastable defocusing technique. The major fragment ions all contain arsenic and may be ascribed structures implying divalent/trivalent arsenic. Ions implying tetravalent/pentavalent arsenic as well as double hydrogen rearrangement processes are hardly recognisable; this is in contrast to the findings reported for the corresponding phosphorous compounds, with which a comparison is made. The present results are in accordance with the view that arsenic is less capable than phosphorous of achieving multiple bonding to other atoms by means of its empty d orbitals.     

The NMR spectra and conformations of cyclic compounds–VIII. Car-3-ene

The 220 MHz PMR spectrum of car-3-ene (3,7,7-trimethylbicyclo[4,1,0]hept-3-ene) is interpreted and a conformation deduced. In contrast to previous work, which has discussed a highly buckled structure for the 6 membered ring, the present work finds this ring to be essentially planar.     

Mass spectrometry of hop compounds—III. Mass spectra of substituted 1,3-cyclopentanediones derived from hop constituents

The mass spectra of isohumulones (IV, V), tetrahydroisocohumulones (VI, VII), tetrahydroisohumulones (VIII) neohydroisocohumulones (XI, XII) cohumulinic acid (III), lupuloxinic acid (XV), humulinone (XIV) and related compounds are described. Ions which appear to be diagnostic for particular structures are discussed.     

Mass spectra of benzoxazolone derivatives

N-Acetonylbenzoxazolones containing a substituent in the acetonyl residue, as well as their hydrazones and oximes, decompose under the influence of electron impact to give primarily fragments of N-methylene- or N-methylbenzoxazolones. For the oximes and hydrazones the characteristic ions are (M -OH) and (M — NH₂), which evidently have cyclic structures. The isomeric aryl triazinones undergo fragmentation via the scheme of the retrodiene synthesis. The characteristic ions that make it possible to distinguish the isomeric benzoxazolones, arylimidazolones, and aryltriazinones were found.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1493–1497, November, 1976.     

Mass spectra of phenoxyacetyl derivatives

The electron-impact-induced mass spectra of substituted N-phenylphenoxyacetamides are discussed. The structure of the rearrangement ion at m/z 108 is investigated and compared with the molecular ion of anisole by metastable ion and corrected collisionally activated dissociation spectra.     

Mass spectra of nucleoside derivatives

The mass spectra of derivatives of uridine, adenosine, cytidine and guanosine are recorded. Derivatization techniques include permethylation, acetylation, trifluoroacetylation, trimethylsilylation and the synthesis of 2′,3′-O-isopropylidenes and 2′,3′-O-phenylboronic esters. Sequential derivatization by a selective combination of some of these procedures results in nucleosides which are blocked with a characteristic group at the cis 1,2 diol position, and, which contain other substituent groups that enhance the volatility of the compound. The specific substitution at the cis-glycol region has been shown to be particularly useful in asymmetrically derivatizing dinucleoside phosphates since certain fragment ions from their mass spectra indicate the sequence of the two nucleoside components. Sequence isomers such as adenylyl-(3′-5′)-uridine and uridylyl-(3′-5′)-adenosine can be unambiguously distinguished.     

Mass spectra of some oxadiazole derivatives

The mass spectra of some substituted oxadiazoles have been determined and analysed with the aid of high resolution mass spectrometry. Some characteristic and major differences between their spectra have been noted, and possible rationalizations have been advanced. The main fragmentation patterns of the 1,3,4-oxadiazole derivatives have been interpreted in terms of diazirine intermediates. Specific skeletal rearrangement processes have been observed in the spectra of the 1,3,4- and 1,2,4-oxadiazoles, and possible mechanisms are proposed.