The composition of the evolved gases from the thermal decomposition of certain metal sulfates

By the use of TG—MS, the thermal dissociation of anhydrous CuSO₄ and Al₂(S0₄)₃ was found to proceed according to the reactions:

followed by the reactions:

No SO₃ was indicated in the dissociation of alunite. The sulfate ion appears to dissociate by at least two different mechanisms although the parameter which controls the mechanisms has not been elucidated.     

Excited-neutral-metastable SO2 formation in the , O3-olefin-SO2, and active nitrogen-SO2 systems

Long-liied (τ > 10^?3 s), electronically-excited (E * > 4 eV) neutral metastables, whose formation was attributed to the presence of SO₂, were observed in the three titled systems. Their possible identity as collisionally-accessed metastable states of the normal

, cyclic

, or superoxide

isomers of SO₂ is discussed.     

A direct synthesis of 1,3-bis(bromomagnesio)propane

Careful addition of 1,3-dibromopropane

to magnesium in Et₂O yields 1,3-bis(bromomagnesio)propane

which is purified via “magnesacyclobutane”

. Reactions of

with H₂O, CO₂, HgBr₂ and Me₃SnCl are reported. MgBr₂ catalyses the decomposition of

to allylmagnesium bromide

.     

Laser flash photolysis of iodine-iodide mixture in hydroxylic solvent. Evidence for the existence of the radical anion I

The laser flash photolysis of iodine-iodide mixtures in alcoholic solvents produces transient species absorbing in the red and near infrared region with maxima at 740 and 590 nm. The 740 nm absorption band has already been attributed to the well known I

ion. In this work the 590 nm absorption band is assigned to the I

radical anion which presumably could be formed by the equilibrium reaction: I

+ I₃^- ? I

. The variations of the intensities of the 590 and 740 nm transient absorption bands as a function of I₃^? concentration, temperature and solvent, support this assignment. The kinetics of formation of I

and I

has been studied in solutions of tertiary butanol. An analysis of the experimental results shows that the I

ion could be formed via a mechanism involving an I

intermediate.     

The preparation of perfluorinated esters of fluorine containing tertiary alcohols

The reaction of an aromatic lithium reagent, LiR, with a perfluoroacid anhydride (RfCO)₂O, in ether solution at low temperatures, produces esters of composition

in addition to the expected ketone

. Mixed esters of composition

may be prepared by starting with a ketone

and reacting with a lithium reagent LiR followed by perfluoroacid anhyride (RfCO₂O. Hydrolysis of the esters provide a convenient route to trertiary alcohols of composition Rf(R) ₂COH.     

Synthese de la phenyl-2-dimethyl-4,5-phosphorine a partir du benzyl-1-dimethyl-3,4-phosphole

1-Benzyl-3,4-dimethylphosphate

-$\text{1}$ is converted into 2-phenyl-4,5-dimethyl-λ₃-phosphorin

-$\text{2}$ through 1,2-dihydro-λ₅-phosphorines

$\text{3}$ and

$\text{s}$.     

Some chlorine fluorosulfonate and peroxydisulfuryl-difluoride reactions

Chlorine fluorosulfonate adds exceptionally easy not only to various alkenes, perfluorobenzene, but to alkynes too

The addition of peroxydisulfuryldifluoride to alkyl- and perfluoroalkyliodides leads to unstable adducts, which decompose with the formation of alkylfluorosulfonates and iodine fluorosulfonate; the latter was trapped with fluoroalkenes

The use of ClOSO₂F allows to substitute selectively for the fluorosulfonate group the chlorine atom in monochloroacetic acid esters as well as the fluorine atom in hexafluoroacetone N-fluoroimine

ClOSO₂F serves as an exceptionally active chlorinating reagent for fluorinated alcohols, nitrosocompounds, perfluoroacid amides and particularly for benzene

The reaction of (OSO₂F)₂ with perfluoroacid amides leads to the corresponding N,N-bis(fluorosulfonate)amides, which easily rearrange into alkylfluorosulfonates

The hypochlorites of fluorinated alcohols are stable enough and they, similarly to ClOSO₂F, are able to add to alkenes, fluoroalkenes (but not to perfluoroisobutylene), bis(trifluoromethyl)ketene, trifluoromethylisocyanate and perfluoronitriles

The fluorosulfonatoacetic acid esters are unstable at the ambient temperature, but they can be widely used in situ as a very effective alkylating reagents

     

Electrogeneration of triplet states of intramolecular anthracene-amine systems

In the electron transfer between the cation radicals

of the amine moiety of four intramolecular anthra cene-amine systems and the anion radicals B^XXX of some heterocyclic and carbonyl compounds in acetonitrile/toluene, the triplet state of the anthracene moiety

is formed. As intermediates in this process, intramolecular and intermolecular triplet exciplexcs

or

and

or

are discussed.     

The preparation of fluxional tetrahydrides, (R  H or Me) and their reactions with CO,ButNC or HBr

The cyclometallated monohydrides

(R  H or Me) react with NaOPrⁱ/PrⁱOH/H₂ to give fluxional tetrahydrides, probably

. These are highly fluxional having magnetically equivalent hydridic hydrogens, even at ---100°C. When treated with HBr,

, gives

and with CO it gives a mixture of complexes which are probably

(2 isomers) and

. When treated with Bu^tNC this tetrahydride undergoes similar reactions but another (major) product is formed which appears to be binuclear and fluxional and is probably of type

, with four bridging hydrogens.     

η2-acylcarbonylvanadium-verbindungen

Substituted vanadium carbonyl compounds with η²-bonded acyl ligands (η²-RCO)V(CO)₃

(

= ditertiary phosphines or arsines: dppe, dppp, dppm, diars, arphos, dpase) have been prepared by photochemical reaction of [V(CO)₄

] with various substituted benzoyl chlorides and cyclopropanylcarbonyl chloride.Effects of aromatic substituents and

upon the thermal stability of the η²-acylcarbonylvanadium compounds are discussed. IR ν(CO) force constants and ⁵¹V NMR signals are linearly correlated with Hammett's σ constants of the aromatic substituents.The preparation of V(CO)₂Cl(diars)₂ is described.     

Reactions of pentafluorosulfanyl isocyanate with NR3 and PR3 compounds; Preparation and characterization of novel compounds SF2NC(O)NHC(O)OCH3 and 1,4-SF5NHC(O)OC6H4OH

The reaction of Pentafluorosulfanyl Isocyanate, SF₅NCO, with tertiary amines has led to 1:1 adducts which have been shown to be zwitterionic in nature by infrared and NMR spectroscopy.

These adducts are far less thermally stable than the analogous fluorosulfonyl derivatives recently reported by Appel and Montenarch¹. The reaction of SF₅NCO with triphenyl- phosphine gave some evidence for the zwitterionic derivative, but the product could not be isolated even when SF₅NCO was used in excess. Recently we have also isolated

from the reaction of SFE₂NC(O)NCO with methanol, and

from the reaction of SF₅NCO with hydroquinone. Both of these novel compounds were unexpected.The physical properties of

, SF₂NC(O)NHC(O)OCH₃, and 1,4-SF₅NHC(O)OC₆H₄OH, prepared during this study, will be discussed in detail.     

Sussex-N.P.L. computer analysed thermochemical data: Organic and organometallic compounds : J.B. Pedley and J. Rylance,University of Sussex, 1977 £10.00

The formation of new

intermediates and especially germaimines R₂GeNR′ has been observed in the reaction of germylenes with phenyl azide (precursor of phenylnitrene). These transient derivatives lead, by polycondensation reactions, to the corresponding cyclic or linear germazanes

, and are characterized by insertion reactions into the germanium—nitrogen bond, cleavage and addition reaction with tetrahydrofuran, and pseudo-Wittig reactions with benzaldehyde. The latter produces the corresponding germoxanes via new

intermediates and phenyl benzaldimine.     

Doping-addition of arylsulfenyl chlorides to the tricyclo[4,2,2,02,5]deca-3,7,9-triene system: skeletal rearrangements and serendipitious products

“doping-addition” of 2-NO₂C₆H₄SCl to the tricyclo[4,2,2,0^2,5]deca-3,7,9-triene system

occurs to give unusual products: (i) rearranged caged cyclopropane

and (ii) the stable cross-perchlorate

.     

Oxidation processes for tetraethyllead and tetramethyllead in dichloromethane at mercury electrodes

Electrochemical studies on tetraethyllead and tetramethyllead at mercury electrodes in dichloromethane are characterised by a one electron oxidation process in contrast to the two electron step reported for the tetraphenyllead compound. Short time pulse techniques and coulometric techniques with tetraethyllead are consistent with the mechanism:

The initial reaction pathway with the methyl analogue is the same. However, long time scale experiments with tetramethyllead are modified by further reactions of the kind

New studies on tetraphenyllead employing variable time domain pseudo derivative normal pulse polarography show that the oxidation of this compound is also consistent with a one electron process at very short times. However the Φ₃Pb radical is slower to dimerise than the alkyllead radicals and so direct reaction with ΦHg⁺ is observed to generate Φ₃Pb⁺ and Φ₂Hg. A subsequent electrochemical process involving Φ₃Pb⁺ at the mercury electrode is responsible for the overall two electron transfer reaction observed.     

Monofluoration stereoselective par le phenyltetrafluorophosphorane (PhPF4) Part. II. Application a la synthese des isomeres thréo et érythro des alkyl-2 fluoro-3 phenylpropanoates de methyle. Analyse conformationnelle par R.M.N. de 19F et 1H.

The stereoselective fluorination of four couples of diastereoisomeric 2-alkyl 3-hydroxy 3-phenylpropanoic methyl esters

by the reaction of the phenyltetrafluorophosphorane with the corresponding trimethylsilylethers derivatives

is described. The structure of the 2-alkyl 3-fluoro 3-phenyl propanoic methyl esters

obtained quantitativly has been determined unambiguously by NMR analysis. ¹⁹F NMR results permit us to determine the relative populations of the rotamers for each of the isomers threo and erythro.     

Especes multiliees dans la chimisorption de co (Ni/Si O2, Ni/Al2O3, Co/Al2O3, Co,Pd/SiO2)

The application of chemical trapping to chemisorbed CO has led to the characterization of multibonded species

on Ni/SiO₂, Ni/Al₂ O₃ , Co, Co/Al₂O₃ and of a bridged form

on Pd/SiO₂. A structure like

[proposed by Muetterties) is in good agreement with infrared and magnetic studies of CO chemisorption on Ni/SiO₂.     

Diversity of the gramicidin a spatial structure: two-dimensional 1H nmr study in solution

Theoretical consideration reveals a unique relationship between NMR spectral parameters and possible types of the gramididin A spatial structure. By means of two dimensional NMR spectroscopy four distinct species were detected simultaneously in ethanol solution. Comparison of experimental data and theoretical conclusions demonstrates that species 1 and 2 are left-handed parallel double helices

differing in relative arrangement of the two polypeptide chains within the dimers, species 3 is left-handed antiparallel double helix

, and species 4 is a mirror image of species 1, i.e. right-handed parallel double helix

. The results are compared with those on spatial structures of the peptide in complex with cesium (right-handed antiparallel double helix

) and of the gramicidin A transmembrane ionchannel (N-terminal to N-terminal single-stranded dimer

).     

Composes du phosphore diccordonne: Synthese et reaction de phosphazenes acycliques

The reaction of Mes-PCl₂ with several amines gives new compounds, oligomers of Mes-P=N-R. Chemical properties of these oligomers are investigated: action of alcohols and disubstituted amines (XH) gives

, the formation of which are only consistent with the presence of a dicoordinated phosphorus compound, Mes-P=N-R, in equilibrium with a tetramer

     

Preparation and reactions of trifluoromethyl-sulfur oxide nitride

In the reaction of CF₃SOCl with NaN₃ or (CH₃)₃SiN₃, azide, CF₃SON₃ (I) is formed:

Upon gentle warming to room temperature, (I) decomposes under evolution of N₂ to give CF₃SON (II),

which however oligomerizes instantaneously, The monomeric nitride(II) can be captured in the presence of reactive halogene compounds to yield N-substituted trifluoromethan-imino sulfonyl chlorides. With CH₃CN, a six-membered ring compound is obtained: