bluuebunny/crossref_metadata_2025_split huggingface dataset:
Triphenylphosphonium and triethylphosphonium halides
Authors: van den Akker M. , Jellinek F. 
Published: September 2010

AbstractReaction of triethylphosphine with HI, HBr or HCl in ethereal solution yields the solid triethylphosphonium salts Et3PHI, Et3PHBr and Et3PHCl, respectively. Infrared spectroscopy indicates the presence of hydrogen bonds Et3PHX, the strengths of these bonds increasing in the sequence X = I < Br < Cl. By reaction of triethylphosphine with HF liquid products are obtained, consisting of (mainly) Et3PHF or Et3P · 2 HF (depending on the ratio of the reactants). While Et3PHF shows very strong PHF bonding and thus resembles a (polar) molecular compound, Et3P · 2 HF is salt‐like, consisting of the ions [Et3PH]⊕ and [HF2]⊖. Solutions of water in triethylphosphine contain a considerable proportion of Et3PHOH, which has a PHOH bond of moderate strength.Triphenylphosphine in ether reacts with HI or HBr to form the solid triphenylphosphonium salts Ph3PHI and Ph3PHBr; with HCl the solid salt Ph3P · 2 HCl is formed. This salt consists of the ions [Ph3PH]⊕ and [HCl2]⊖; it is the first reported [HCl2]⊖ salt of a phosphonium base. Ph3P · 2 HCl slowly decomposes into triphenylphosphine and hydrogen chloride; Ph3PHCl may be an unstable intermediate in this reaction, but no evidence was found for the existence of Ph3PHCl as a stable compound. The alleged compound Ph3P · 1.33 HCl1 is a mixture of Ph3P · 2 HCl and Ph3P. Triphenylphosphine reacts with HF to form liquid products consisting of Ph3PHF and Ph3P · 2 HF, the latter compound consisting of [Ph3PH]⊕ and [HF2]⊖ ions. Very strong PHX bonds are found in Ph3PHF; in Ph3PHBr and Ph3PHI the PHX bonds are considerably less strong, while such bonds are absent in Ph3P · 2 HCl and Ph3P · 2HF. The differences between triphenylphosphine and triethylphosphine in their reactions with hydrogen halides (and water) can be explained by their difference in basicity.
The conformation of non‐aromatic ring compounds. Part 37: The Crystal Structure of 2‐Oxo‐2‐phenoxy‐1,3,2‐dioxaphosphorinane
Authors: Geise H. J. 
Published: September 2010

Abstract2‐Oxo‐2‐phenoxy‐1, 3, 2‐dioxaphosphorinane (propane‐1, 3‐phenylphosphate) crystallizes in the orthorhombic system, space group Pna21, Z = 4. The unit cell dimensions are a = 15.55, b = 11.06, c = 5.97 Å. The structure was solved by the heavy atom technique and refined by the method of least squares using eye‐estimated three‐dimensional data obtained with copper radiation at room temperature. The dioxaphosphorinane ring has the chair conformation with the double‐bonded oxygen in equatorial and the phenoxy group in axial position.
The degradation reaction of histidine with iodine
Authors: Schutte L. , Havinga E. 
Published: September 2010

AbstractThe reaction of histidine and some other imidazole derivatives with iodine at pH8 and 50° has been followed to completion (uptake 8 moles I2 per mole histidine). Products of the I2‐degradation of histidine are: carbonate, iodoform, oxalic acid, ammonia and iodide. The origin of the reaction products has been traced by using radioactively labelled compounds. An overall equation for the reaction is deduced and a tentative scheme for a reaction path is presented.
Properties of diazosulfonates. Part I: The dissociation of methoxybenzenediazosulfonates
Authors: van Beek L. K. H. , Helfferich J. , Jonker H. , Thijssens Th. P. G. W. 
Published: September 2010

AbstractThe sulfite concentrations in aqueous solutions of methoxybenzenediazosulfonates of pH = 7.8 were determined by dead‐stop end‐point titrations at 25°. ortho‐Methoxybenzenediazosulfonate dissociates slowly after being dissolved in water.Dissociation and rate constants derived are K = 2.4 × 10−10 mole l−1 = ka/kb, with ka = 9.0 × 10−8 s−1 and kb = 375 1 mole−1 s−1. para‐Methoxybenzenediazosulfonate is immediately at its equilibrium dissociation in solution with K = 6.6 × 10−10 mole l−1, ka = 1.5 × 10−8 s−1 and kb = 23 1 mole−1 s−1.
Peak broadening in paper chromatography as a function of the flow‐rate of the eluent
Authors: de Ligny C. L. , Remijnse A. G. 
Published: September 2010

AbstractPeak broadening in paper chromatography has been investigated as a function of the flow‐rate of the eluent.The contribution of longitudinal diffusion and the combined contributions of resistance to mass‐transfer and eddy diffusion to peak broadening have been calculated separately.The last‐mentioned effects are responsible for more than 50% of the peak broadening at the flow‐rate which is obtained in practice, and for medium Rf values.It appeared, once more, that longitudinal diffusion occurs both in the mobile and in the stationary phase.
The synthesis of lactones. Part II: Some 2‐alken‐5‐olides and 2,4‐dodecadien‐5‐olide
Authors: Lamberti V. , Weller W. T. , Schogt J. C. M. 
Published: September 2010

AbstractA series of 2‐alken‐5‐olides has been prepared from 1‐alkyn‐4‐ols by carbonation of their Grignard reagents and selective hydrogenation of the triple bond of the obtained 5‐hydroxy‐2‐alkynoic acids. The lactones were prepared by dehydration of the 5‐hydroxy‐2‐alkenoic acids.The reaction between 2‐alkenals and malonic acid to give 2,4‐dienoic acids also results in the formation of 2‐alken‐5‐olides as by‐products.2,4‐Dodecadien‐5‐olide was prepared by bromination of 2‐dodecen‐5‐olide with N‐bromosuccinimide followed by dehydrobromination.
Synthesis of acetals by alkylation of 1,1‐diethoxy‐2‐propyne
Authors: Ward J. P. , van Dorp D. A. 
Published: September 2010

AbstractAcetals were synthesized by alkylation of 1,1‐diethoxy‐2‐propyne with pentyl bromide, isopentyl bromide, phenyl‐2‐propynyl bromide, trans‐cinnamyl bromide, or with 1‐bromo‐2‐phenylacetylene or 1‐bromo‐1‐heptyne (Cadiot‐Chod‐kiewicz coupling). The results of partial hydrogenation with Lindlar's catalyst and of reduction with sodium in liquid ammonia of some of the products are described.
Ring transformations in reactions of heterocyclic halogeno compounds with nucleophiles. Part X: A tracer study of the conversion of 4‐chloro‐2‐phenylpyrimidine into 4‐amino‐2‐phenylpyrimidine
Authors: van Meeteren H. W. , van der Plas H. C. 
Published: September 2010

AbstractIt is shown that in radioactive 4‐amino‐2‐phenylpyrimidine, obtained as a minor product in the reaction of 4‐chloro‐2‐phenylpyrimidine‐4‐14C with potassium amide in liquid ammonia, the 14C label is present in position 4 of the ring. This result proves that the formation of the 4‐amino compound cannot be accomodated with a mechanism initiated by the attack of an amide ion on the 6 position, but probably occurs by an addition‐elimination mechanism on the C(4) carbon atom.
The chemistry of cyclopropanones. Part VI: Addition of 1,1‐dihydroxycyclopropane
Authors: Schaafsma S. E. , Steinberg H. , de Boer Th. J. 
Published: September 2010

AbstractOn adding a slight excess of water to cyclopropanone, 1,1‐dihydroxycyclopropane (cyclopropanone hydrate) can be isolated in a high yield.The hydrate adds to cyclopropanone giving a mixture of α,ω‐dihydroxypoly‐(oxycyclopropylidenes), which are isolated as the acetates.
Preparation and thermal decomposition of 5‐pentyl‐1,2,3,4‐thiatriazole
Authors: Wijers H. E. , Brandsma L. , Arens J. F. 
Published: September 2010

AbstractThe unstable 5‐pentyl‐1,2,3,4‐thiatriazole (IV) has been prepared from acetylthiohexyne (I) and ammonium azide in dimethyl sulfoxide. Thermal decomposition of IV in polar solvents gives pentyl cyanide, sulfur and nitrogen, whereas in non‐polar solvents in addition to these products pentyl isothiocyanate also is formed during thermolysis.
Electron diffraction by gases: The length of the peri‐bonds in perylene
Authors: Dallinga G. , Toneman L. H. , Traetteberg M. 
Published: September 2010

AbstractThe authors have reconsidered what is known about the structure of perylene and carried out some additional calculations concerning earlier gas diffraction work. They conclude that the length of the peri‐bonds is now well established at 1.473 ± 0.005 Å, which is the average of the gas‐diffraction value (1.474 ± 0.014 Å) and two X‐ray results. This value does not differ significantly from theoretical values based on bond order‐bond length relations.
Natural coumarins. Part IX: Mass spectrometric evidence for the structure of psoralidin
Authors: Abdel‐Hay F. M. , Abu‐Mustafa E. A. , Fayez M. B. E. 
Published: September 2010

AbstractPsoralidin (C20H16O5, m.p. 290‐292°) is another coumarin constituent of the seeds of Psoralea corylifolia L. Its constitution has recently been disputed and it has been shown by spectral and degradative evidence to be represented by I which was later supported by synthesis. The skeleton of psoralidin (I) is also present in wedelolactone, coumestrol and erosnin which constitute a rare type of natural 3,4‐benzofuranocoumarins.
Properties of diazosulfonates. Part IV: The absorption spectra of o‐ and m‐ substituted benzenediazosulfonates
Authors: van Beek L. K. H. , Helfferich J. , Houtman H. J. , Jonker H. 
Published: September 2010

AbstractThe electronic absorption spectra of o‐ and m‐substituted benzene‐trans‐diazosulfonates in aqueous solution support the assignments given in Part III to the transitions in p‐substituted trans‐BDS. The intensity of the π→π* absorption decreases on OCH3‐trans‐BDS in the sequence para > ortho > meta. The Φ→Φ*, π→Φ*, and Φ→π* absorptions are most intense in 3‐OCH3‐trans‐BDS. In 2‐Cl‐cis‐BDS the π→π* intensity is greatly reduced, whereas the Φ→Φ* intensity is unaffected by trans‐cis isomerization. Electron‐with‐drawing substituents (‐NO2, ‐CO2H, halogen) do not have much influence on the locations of the absorption bands, but electron‐donating groups (‐CH3, ‐OCH3, ‐OH) produce bathochromic shifts of the same order in the ortho, meta, and para positions, whereas an intermediate place is taken by ‐SCH3 and ‐SO3NA. The locations of the Φ→Φ* band (at 210 nm) and the n – π* band (at 420 nm) are not affected by changes in substituents.
Sulfur compounds in free radical reactions. Part I: Cis‐trans isomerism and ultraviolet spectra of arenediazothiolates
Authors: van Zwet H. , Kooyman E. C. 
Published: September 2010

AbstractAlkyl or aryl arenediazothiolates (Ar ‐N = N ‐SR; R = alkyl or aryl), are readily synthesized by reaction of diazonium ions with mercaptides. The former products are generally obtained in the form of cis‐isomers which rearrange thermally to the trans‐derivatives; these may be reconverted to cis‐compounds by exposure to diffuse daylight. Aryl arenediazothiolates were isolated only as trans‐compounds. Cis‐trans isomerism and UV spectra are discussed on the basis of substituent effects both in the aryl and in the alkylthio (or arylthio) moiety.
Thermolytic reactions of esters. Part III: Pyruvates
Authors: Louw R. , Kooyman E. C. 
Published: September 2010

AbstractWhereas pyruvic acid smoothly decarboxylates in the vapour phase to give acetaldehyde, methyl pyruvate is much more stable. Between 440 and 480°, carbon monoxide is eliminated leading to methyl acetate.In an excess of toluene, allyl pyruvate reacts much faster than the methyl ester, giving large proportions of CO2, CO and CH4; 4‐phenyl‐1‐butene and bibenzyl are also important products. Decomposition thus resembles that of allyl acetate11. However, the pyruvate reacts some thousand times more rapidly, the activation energy being 12 kcal · mole−1 lower. This suggests the first step of allyl pyruvate breakdown to be a multiple fission into acetyl, CO2 and allyl. Analogously, benzyl pyruvate decomposes much faster than the corresponding acetate.In an Appendix, kinetic data on allyl and benzyl esters are discussed on the basis of ‐ known or derived ‐ heats of formation; it would appear that consistency is not always satisfactory.
α‐thiopyran‐1,1‐dioxide: A re‐examination of the structure of γ‐thiopyran‐1,1‐dioxide
Authors: Molenaar E. , Strating J. 
Published: September 2010

AbstractThe “γ”‐thiopyran‐1,1‐dioxide, described previously1,2, has proved to be α‐thiopyran‐1,1‐dioxide, as was definitely established by an X‐ray diffraction study as well as by the synthesis of the α‐isomer by an independent route.
NMR kinetic investigation of the system norbornadiene‐μ‐dichloro dirhodium dinorbornadiene. Occurrence of a five‐coordinated rhodium complex
Authors: Volger H. C. , Hogeveen H. 
Published: September 2010

AbstractNMR spectra of solutions containing norbornadiene (N) and μ‐dichloro dirhodium dinorbornadiene (Rh2N2Cl2) at low temperatures (< − 40°C) show the presence of a new species, a five‐coordinated rhodium dinorbornadiene chloride (RhN2Cl). It is formed according toRh2N2Cl2 + 2 N ⇌ 2 RhN2Cl.At higher temperatures (−40° to + 100°C) line broadening is observed, indicating the occurrence of rapid exchange processes. From the data the following mechanism is deduced: a slow reaction (by one or two steps) of the dimeric complex with one mole of NRh2N2Cl2 + N ⇌ RhN2Cl + RhNCl,and a subsequent fast reaction yielding a second mole of RhN2ClRhNCl + N ⇌ RhN2Cl.
Isotope effects in the chlorination of naphthalene
Authors: de La Mare P. B. D. , Lomas J. S. 
Published: September 2010

AbstractThe chlorination of naphthalene shows an inverse deuterium isotope effect, the reaction of naphthalene being slower than that of octadeuterionaphthalene by a factor of 0.85. The product‐forming stages are also subject to a deuterium isotope effect which influences the partitioning between addition and substitution; the most direct interpretation of the results is that the values of kH/kD for the stages of proton‐loss are subject to a normal deuterium isotope effect, with kH/kD ⦔ 1.4.
Chemistry and spectroscopy in strongly acidic solutions. Part XIII: Spectroscopic observation of protonated nitroalkanes
Authors: Hogeveen H. 
Published: September 2010

AbstractSome protonated nitroalkanes in HF‐BF3 and HF‐SbF5 solutions have been observed by NMR spectroscopy. The added proton on the NO2 group absorbs at extremely low field (δ = 16.8‐17.5 ppm from TMS). This deshielding effect is probably caused by both the positive charge and the magnetic anisotropy of the NO2 group. IR data show a parallel between RNO2H⊕‐RNO2 and RCOOH‐RCOO⊖ stretching absorptions. The thermal decomposition of protonated 2‐nitropropane is briefly discussed.
NMR spectra and configuration of phenylallyl and related anions
Authors: Heiszwolf G. J. , Kloosterziel H. 
Published: September 2010

AbstractA number of phenyl‐substituted allyl anions and corresponding isoelectronic oxaallyl anions have been obtained by reacting phenyl‐substituted propenes, phenylacetaldehyde and benzyl methyl ketone with potassium amide in liquid ammonia.The NMR spectra of the anions are decribed. They yield information on the distribution of the negative charge and on the configurations. The configurational stability is also discussed.
The crystal structure of 6,6′‐methylenediphenanthridine
Authors: van Thuijl J. , Romers C. 
Published: September 2010

AbstractThe crystal structure of 6,6′‐methylenediphenanthridine (I), C27H18N2, has been determined from X‐ray diffraction data collected at ‐180°. The crystals are monoclinic; the space group is P21/c with a = 9.52, b = 15.4, c = 6.66 Å, β = 100°, and Z = 2. The planar molecules have a centre of pseudosymmetry coinciding with centres of symmetry in the lattice. The structure being disordered no extensive structure determination has been carried out. Is was found that tetrabenz[a,c,h,j]anthracene (II) is isomorphous with I.
Conversions of sarcosine and pipecolic acid with phenyl and methyl isothiocyanate
Authors: Beyerman H. C. , Maat L. , Sinnema A. , van Veen A. 
Published: September 2010

AbstractSarcosine and pipecolic acid give with phenyl isothiocyanate in an alkaline medium according to the Edman method “abnormal” adducts, the structures of which are elucidated amongst others with the aid of spectroscopic data. In ethanol the 3‐phenyl‐2‐thiohydantoins are formed from the same reactants.With methyl isothiocyanate on the other hand sarcosine and pipecolic acid always give the 3‐methyl‐2‐thiohydantoins, both in an alkaline medium and in ethanol.In the literature contradictions are to be found about the structure of the reaction product of the ethyl ester of pipecolic acid with phenyl isothiocyanate. From our investigation it appears that invariably the phenylthiohydantoin is formed.The proton magnetic resonance spectra of 3‐phenyl‐2‐thiohydantoins of some amino and imino acids are discussed.
Natural chromones. Part VIII: The synthesis of some linear chromonofurancarboxylic acids. A novel total synthesis of visnagin
Authors: Badawi M. M. , Fayez M. B. E. 
Published: September 2010

AbstractA new synthesis of visnagin (I) has been realised by condensation of 6‐formyl‐7‐hydroxy‐5‐methoxy‐2‐methyl‐chromen‐4‐one (II) or its 5‐hydroxy analogue (X) with diethyl bromomalonate and subsequent elimination of the ethoxycarbonyl groups from the resulting intermediates III and IV.
Preparation of thioamides from alkynethiolates and amines
Authors: Schuijl P. J. W. , Brandsma L. 
Published: September 2010

AbstractThioamides RCH2C = S(NR2′) have been prepared in good yields by adding ethereal solutions of lithium alkynethiolates RC ≡ CSLi to an excess of an amine and t‐butyl bromide.
The conformation of non‐aromatic ring compounds.: Part 42. Carbon‐halogen stretching frequencies and conformation of 1‐halogeno‐ and 1‐alkyl‐1‐halogenocyclopentanes
Authors: Buys H. R. , Altona C. , Havinga E. 
Published: September 2010

AbstractThe infrared and Raman spectra of 1‐halogeno‐(1‐alkyl)cyclopentanes have been recorded. It is concluded that the conformations with the halogen atom in axial position predominate in solution, the substituents occupying the most puckered part of the ring. For the 1‐halogenocyclopentanes this observation is confirmed by the NMR spectra. The bands assigned to the equatorial C‐halogen stretching modes are found to be much broader than those due to the axial ones, which is ascribed to a less defined geometry of the equatorial conformers.
Ketene S,N‐acetals from thioamides
Authors: Schuijl P. J. W. , Bos H. J. T. , Brandsma L. 
Published: September 2010

Abstract1‐Dialkylamino‐1‐alkylthio‐1‐alkenes RCH=C(SR″) (NR′2) with R = H or alkyl and R′, R″ = alkyl have been obtained in good yields by treatment of thioamides RCH2C(= S) (NR'2) with one equivalent of potassium amide in liquid ammonia and subsequent alkylation with alkyl bromides R″Br.
A semi‐empirical energy‐level diagram for octahedral, Nickel(II) Complexes
Authors: Reedijk J. , van Leeuwen P. W. N. M. , Groeneveld W. L. 
Published: September 2010

AbstractAn energy diagram for Ni(II) in octahedral environment is constructed from spectral data of a large number of nickel complexes, with the aid of ligand‐field theory. These complexes are placed in a so‐called “Tanabe‐Sugano” series, according to increasing values of Dq/B.Two empirical relations are introduced. One relation between Dq/B and the shape of the second absorption band; and one relation between Dq/B and λ/B.
Oxidation of three N,N′‐diacetyl‐2‐deoxyinosadi‐amines‐1,3 with periodic acid and a tridentate complex of the cis‐cis isomer
Authors: Dijkstra D. 
Published: September 2010

AbstractThe reaction between the periodate ion and 1,2,3‐triols has been studied using substrates in which the hydroxyl groups are attached to a six‐membered ring with a fixed “chair” conformation. The behaviour of the trans‐trans, the cis‐trans and the cis‐cis‐isomers is in line with Barker and Shaw's views on the possible formation of a tridentate complex.
The crystal and molecular structure of 1,3,5,7‐tetramethoxy‐2,6‐dioxa‐adamantane (C12H20O6)
Authors: Kanters J. A. , Hulscher J. B. 
Published: September 2010

AbstractCrystals of 1,3,5,7‐tetramethoxy‐2,6‐dioxa‐adamantane (C12H20O6) are orthorhombic (Pbcn) with a = 10.31, b = 13.23 and c = 9.23 Å; there are 4 molecules in the unit cell; the asymmetric unit consists of one half molecule. 460 independent three‐dimensional intensities were collected on a Nonius retigraph. The structure was solved by a systematic sign correlation procedure and refined by using least squares methods to R =.062. The coordinates of the carbon and oxygen atoms were refined with anisotropic thermal motion, those of the hydrogen atoms with a constant isotropic thermal parameter. The geometry of the adamantane skeleton of the molecule does not differ greatly from that of adamantane, in spite of the fact that two methylene carbon atoms are replaced by two oxygen atoms. The molecule has a two‐fold axis coinciding with the space‐group two‐fold axis.
Mono‐ and dicarbonium ions of β‐dicarbonyl compounds (ketones, carboxylic ACIDS and esters)
Authors: Brouwer D. M. 
Published: September 2010

AbstractA PMR spectroscopic study is described of the protonation of a series of β‐dicarbonyl compounds (Table I) in HF‐SbF5. At high acidity they form 1,3‐dicarbonium ions, except in the case of compounds VI and VII. At lower acidity monocations are formed: diketones give allylic type monocations, and keto esters, dicarboxylic esters and acids give alkoxyhydroxy and dihydroxy‐carbonium ions, respectively.Between these two groups there is a marked difference in spectroscopic behaviour of solutions containing comparable amounts of mono‐ and dications. Equilibration of mono‐ and dications is “slow” with the diketones and “fast” with the other compounds.For the compounds studied, the equilibrium constants KB* = [dication]/[monocation] [H2F+] vary from less than 10−2 for tri‐ and hexafluoroacetylacetone to more than 107 for ethyl acetoacetate. The monocation‐dication equilibrium systems are useful as indicators and buffers at high acidity; they are unreactive towards alkylcarbonium ions. A lower limit has been established for the basicity of isobutene, which turns out to be much more basic than benzene.
On silicon tritelluride, Si2Te3, and alleged phosphorus tritelluride
Authors: Haneveld A. J. Klein , van der Veer W. , Jellinek F. 
Published: September 2010

AbstractSilicon(III) telluride, Si2Te3, which was formerly regarded as SiTe2, is hexagonal with a = 7.429 Å; c = 13.471 Å; c/a = 1.813. There is a pronounced subcell with a′ =1/3 √3 a, c′ = 1/2 c. The tellurium atoms are in a hexagonal close packing; the Si atoms occupy tetrahedral and probably also octahedral holes in this packing, but their detailed arrangement could not be determined unambiguously. The alleged compound P2Te3 has been found to be a mixture of tellurium and amorphous red phosphorus.
Synthesis of oxytocinoic acid and oxytocin on a solid support VIA triazolides from active esters
Authors: Beyerman H. C. , Boers‐Boonekamp C. A. M. , van den Brink‐Zimmermannová H. Maassen 
Published: September 2010

AbstractThe syntheses are described of S,S′‐dibenzyloxytocinoic acid and S,S′‐dibenzyloxytocin on copolystyrene‐divinylbenzene according to the solid‐phase method of Merrifield, but using the triazolide method of coupling developed in this Laboratory. Cleavage with amide formation of the nonapeptide‐polymer bond by ammonolysis proceeded quite satisfactorily with methanolic ammonia. The nonapeptides were obtained in the pure state by mere crystallization.The conversions of the linear nonapeptides into the cyclic compounds oxytocinoic acid and the hormone oxytocin are known.
Thermal isomerisation of trimethylcyclopentadienes
Authors: de Haan J. W. , Kloosterziel H. 
Published: September 2010

AbstractThe thermal behaviour of 1,5,5‐ and 2,5,5‐trimethylcyclopentadiene (TMCPD) has been investigated. The following isomerisations have been observed and their activation parameters determined:Evidence is presented that these reactions occur by an intramolecular, sigmatropic 1,5 shift of a methyl group.
Correlations between molecular structure and mass spectra. Part II: The mass spectrometric fragmentation behaviour of isopentyl cyanide and its deuterium analogues
Authors: Rol N. C. 
Published: September 2010

AbstractThe fragmentation of the isopentyl cyanide ion has been investigated by means of deuterium labelling and precision mass measurements. The results throw light on interesting fragmentation reactions. Comparisons with the reactions postulated to account for the mass spectra of cyanides, especially those of isohexyl cyanide and its deuterium analogues, reveal some unexpected features.