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Transport Processes of Noble Gases in Solids especially Nuclear Fuels.

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vS (0-H)
vas(O- H)
vf O.--H-)
Ss(O-O-H)
3270 s h
3291
3170 ms 3208
2820 m , 2732 [a]
broad
1403 m w 1404
6,,(0--0-H)
v(0-0)
~~(0-0-H)
1388 ms
920 mw
640 mw
1380
880
635
From comparison of the long-wave shift of vs- and vas(O-H)
with gaseous and liquid H202 [v(O-H) at ca. 3600 and 3400
cm-1, respectively] 191 it follows, in accord with expectations
for structure (4),that neither H202 molecule contains a free
O H group and thus that both H202 are acting as bidentate
ligands forming strong hydrogen bonds to the oxygen atoms
that are bound to arsenic. That their bidentate function is
intramolecular follows from the monomeric molecular state
of ( 4 ) . Further, the eleven-membered spirocyclic rings enable
the H202 molecules to retain the energetically favored [lo]
trans-arrangement of the H atoms. The trans-arrangement
of H atoms is confirmed also by the low intensity of v ( 0 - 0 )
(small dipole moment of the 0-0 group). Although the
intense broad absorption of the (As=O) stretching vibration
occurs in the region of the (0-0) stretching vibrations1111
and it is conceivable that it hides v ( 0 - 0 ) , the assignment of
the band a t 920 cm-1 to v(0-0) seems nevertheless certain
since there is no band at 920cm-1 in (5). The stretching
vibration for the (=O...H-) bridgesrsl is assigned to the
broad band a t 2820 cm-1. With few exceptions (61 coordination of (As=O) groups to metals shifts the v(As-0) absorptions to lower wave numbers; that such a shift is substantially
absent for (4)may be due to the smaller mass and the smaller
electron-acceptor ability of the protons of hydrogen peroxide.
Experimental:
A mixture of compound ( 3 ) (700 mg, 0.71 mmole) and
acetone (50 ml) is treated with 30 % H 2 0 2 (1 ml, ca. 9 mmoles)
with stirring and heating under reflux. It dissolves slowly,
leading in about 30 min to a clear colorless solution, which is
heated for a further 30 min. Acetone, water, and excess of
hydrogen peroxide are then removed under reduced pressure
at 15 "C, leaving a colorless oil that crystallizes in a vacuum.
This residue is dried for ca. 30 min under high vacuum, then
dissolved in CH2C12 (10 ml) and reprecipitated with petroleum ether (50 ml). The then analytically pure product is
filtered off, washed four times each with 5 ml of petroleum
ether, and dried under high vacuum; it is very readily soluble
in CH2C12 and CHC13, soluble in acetone and acetonitrile,
and almost insoluble in ether, petroleum ether, CS2 or benzene. Yield 80%. M.p. from 104 OC with loss of H202.
If the adduct ( 4 ) is heated for 5-6 h under high vacuum at
130-140°C, H202 distils off and a brownish product is
obtained that is dissolved in CH2C12 (10 ml) and reprecipitated with petroleum ether (25 ml). Compound (5) is thus
obtained colorless and crystalline; it is filtered off, washed
several times with 5 ml of petroleum ether, and dried under
high vacuum. M.p. 204-207 "C (decomp.).
Received: June 11, 1968
[ Z 841 IEI
German version: Angew. Chem. 110, 755 (1968)
[ * ] Dr. J . Ellermann and Dipl.-Chem. D. Schirmacher
Institut fur Anorganische Chemie
der Universitat Erlangen-Niirnberg
852 Erlangen, Fahrstr. 17 (Germany)
[I] Part 18 of Spiroheterocyclic and Heterobicyclic Compounds.
- Part 17: J . Ellermann and W . H . Gruher, Z. Naturforsch., in
the press.
121 J. Ellermann and K . Dorn, Chem. Ber. 99, 653 (1966).
[ 3 ] J . Ellermann and D . Schirmacher, Chem. Ber. 100, 2220
(1967); and literature cited there.
[4] J . Ellermann and K . Dorn, Chem. Ber. 100, 1230 (1967).
[5] The vibrations of the four As=O groups and the =O - . . Hbridges, as well as those of the two added H202 molecules, are
only to be observed singly, since the individual As=O groups
in ( 4 ) do not enter into valence or mass coupling with one another. This is in agreement with the predictions of the local
symmetry method (cf. F . A. Cotton, A . Liehr, and G. Wilkinson,
J. inorg. nuclear Chem. 2, 141 (1956)).
[6] G. B. Deacon and R . S . Nyholm, J. chem. SOC.(London)
1965, 6107, and literature cited therein.
171 R . L. Miller and D . F. Hornig, J. chem. Physics 34, 265
(1 961).
[8] G. V . Howell and R . L. WiNiains, J. chem. SOC.(London)
A 1968, 117.
[9] K. Nakamoto: Infrared Spectra of inorganic and Coordination Compounds. Wiley, New York 1963, p. 97.
[lo] R. H . Hunt, R . A . Leacock, C . W . Peters, and K. T.Hecht,
J. chern. Physics 42, 1931 (1965).
[ l l ] W . P. Griffithand T . D. Wickins, J. chem. SOC.(London)
A 1968, 397.
C O N F E R E N C E REPORTS
Transport Processes of Noble Gases in Solids,
especially Nuclear Fuels
By K . E. Zimen[*]
There are solid systems in which noble gases are produced
naturally: minerals that contain U, Th, or K from which 4He,
219Rn, 220Rn, 222Rn, or 40Ar arises in geological times; also
meteorites in which some primordial noble gas may be present
and in which some cosmogenic noble gas may have arisen by
nuclear spallation reactions.
There are also solid systems, and in particular fuels, in
which noble gases are formed artificially. The fission products
of U or Pu consist to about 30% of Kr and Xe. Furthermore,
noble gases can be incorporated into almost all solid bodies
artificially, by nuclear reactions, ion bombardment, nuclear
recoil, or entry by diffusion.
Noble gases, whether produced naturally or artificially, are
normally present in the solid bodies in atomically disperse
form and diffuse out after their formation because of their
Atigew. Chem. internat. Edit.
1 Val. 7 (1968) 1 No. 9
extremely low solubility. Further, the noble gases can escape
owing to recoil during the nuclear transmutation and in
certain cases by formation of bubbles, which are moving in
temperature gradients. In addition, changes in the solid
body - evaporation, recrystallization, and surface reactions
- naturally contribute to the loss of noble gas.
Investigation of the behavior and transport of noble gases
began with the so-called Hahn emanation method, in which
the natural emanations were used for qualitative observation
of physical and chemical changes in solids as a function of
temperature or time. Today, diffusion coefficients and
activation energies of noble gases can be determined quantitatively, and in individual cases the kinetics of diffusion of
noble-gas atoms and observation of recoil effects can be used
to provide information about fine structure and vacancies in
crystalline and amorphous solids - information that cannot
be obtained from diffraction methods (X-ray, neutrons),
which depend on periodic structure. Of particular importance
is the release of fission gases from nuclear fuels because of
build-up of pressure in the fuel elements and contamination
of the circulating coolant from defective fuel-element cans.
139
The relevant publications from the Hahn-Meitner-lnstitut,
numbering fourty up to the present, were reviewed.
[VB 121 IE]
Lecture at Darmstadt (Germany) on May 28, 1968
German version: Angew. Chem. 80, 706 (1968)
[*] Prof. Dr. K. E. Zimen
Hahn-Meitner-Institut fur Kernforschung
1 Berlin 39, Glienicker Str. 100 (Germany)
Study of the Mechanism of Dehydrogenase
Reactions by Measurement of the Isotope Effects
By D . Palm [*I
Classical kinetic methods for the study of enzyme reactions
have recently been extended by methods for selective determination of fast or slow steps in complex reaction sequences.
Slow and irreversible steps can be detected also in enzyme
kinetics by differences in the reaction rate of isotopically
labeled substrates. This is particularly so for the isotope
effects (IE’s) of the hydrogen isotopes, for which primary and
secondary IE’s can be detected 111. Thus hydrogen transfer in
NAD-dependent dehydrogenases is particularly suited for
investigation of the empirical and theoretical relation of IE
to enzyme-kinetic values.
The primary IE (4.1 to 6.8 at 25OC) for the substrates
[I-TI-ethanol, -1-propanol, and -1-butanol confirm the required rate-determining hydrogen transfer for alcohol dehydrogenase (ADH) from yeast, but an increase in IE with
rising temperature also shows a change in the rate-determining step. For the ADH of liver the small secondary IE
(1.4 to 1.6 at 25 “C) for the homologous alcohols is in agreement with a rate-determining dissociation of the enzyme
NADH complex, which is independent of the substrate.
The reverse reaction, studied with the stereospecifically
labeled [A-4-T]NADH again shows primary IE’s of 2 to 5
(depending on the corresponding homologous aldehydes) for
yeast enzyme, whereas only a small difference from unity was
found for the liver enzyme. The sterically hindered substrate
2-methylcyclohexanone for Iiver ADH stands out with an
IE of 3.6; since 2-[methyZ-T]methylcyclohexanone reacts
4.5 % faster, the site of steric hindrance can be more accurately localized [ZJ.
In the case of lactate dehydrogenase of rabbit muscle the IE
of 2.5 for ~-[ZT]lactatecorresponds to a product of two
secondary IE‘s, which are due to isomerization and dissociation of the enzyme-NADH complex. This interpretation
excludes a kinetic influence of ternary complexes. The reverse
reaction with [A-4-T]NADH also shows an IE of up to 2.0
that indicates isomerizations, but under the influence of
pyruvate inhibition at concentrations > 1 x l o - 3 ~the IE
disappears.
Finally, a mechanism similar to that for yeast ADH can be
ascribed to glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase.
[VB 161 IE]
Lecture at Konstanz (Germany), on May 30. 1968
German version: Angew. Chem. 80, 706 (1968)
[*I Doz. Dr. D. Palm
Chemisches Institut Weihenstephan und
Organisch-Chemisches Institut der Technischen Hochschule
8 Munchen, Arcisstr. 21 (Germany)
[l] H. Simon and D . Palm, Angew. Chem. 78,993 (1966); Angew.
Chem. internat. Edit. 5, 920 (1966).
121 D. Palm, Z. Naturforsch. 216, 540, 547 (1966); D. Palm,
T. Fiedler, and D . Ruhrseitz, ibid. 236, 623 (1968).
Oxidation of Pyrrolic Impurities in Polyamides
By P. Schlack[*l
When prepared under not quite perfect conditions, polyamides may contain pyrrole groups formed in side reactions
and detectable by Ehrlich’s reagent. In nylon 6 (polycapro-
740
lactam) pyrroles are observed particularly if 1,Il-diaminoundecanone is formed by loss of water and COz from two
moles of 6-aminohexanoic acid or if the corresponding anhydro base is formed from c-caprolactam by loss of water.
This ketimine is very sensitive to oxygen and after autoxidation gives an intense pyrrole reaction.
Polycaprolactam fibers (“Perlon”) that contain units of this
imine show a strong tendency to yellow on fairly long exposure to light in the presence of oxygen or on thermal oxidation. Rochas and Martin have found that polyamide fibers
(nylon 66) may also give a positive pyrrole reaction after
photoxidation 111. They assumed that the pyrroles were formed by reaction of amino end groups in the fiber with a,cr’-dioxoadipic acid formed by oxidation of adipyl groups. Mar&
and Larch came to the conclusion that it was almost wholly
the diamine groups that were involved in pyrrole formation;
they held that primary attack by the oxygen was always o n
the methylene groups next to the amide nitrogen 121.
In studies of the yellowing of polyamide textiles in our Institute, F. Sommermann [31 found that pyrroles are also formed
on oxidation of N-free olefinic substances such as 3-heptene,
oleic acid, methyl linoleate, and squalene in the presence of
prjmary amines or amino acids and also on subsequent addition of such amines. Since sweat contains glycerides of polyunsaturated fatty acids, squalene, ammonium salts, and other
nitrogenous bases, pyrroles or their colored oxidation products could be formed on textile substrates even without
chemical participation of the fiber substance.
Only the primary amino end groups of the fiber come into
question as a nitrogen source for pyrrole formation within
the fiber substance. If however, the amino groups are inactivated by acylation, e.g. by acetic anhydride [4J, then pyrrole
can no longer be formed on the fiber unless ammonia or
amino groups are newly formed. Autoxidation in light is then
also greatly hindered. Most of the amino groups can be
blocked under remarkably mild conditions that can be realized in practice, nameIy, by impregnating the textile goods
with solutions of anhydride-forming aromatic polycarboxylic
acids, e.g. trimellitic acid, then drying them, and heating
them for one to two minutes at 170-180°C by passage
through a thermofixing apparatus. The tendency to yellowing
is much reduced by this pretreatment.
From the UV spectra of the dyes formed in the fiber by p (dimethy1amino)benzaldehyde it can be concluded that both
a- and P-methine dyes occur side by side, whereas the dyes
formed from unsaturated fatty acid esters and amino acids
appear to consist mainly of @-derivatives.
[VB 164 IE]
Lecture at Karlsruhe (Germany) on May 30, 1968
German version: Angew. Chem. 80, 761 (1968)
___
[*I Prof. Dr. P. Schlack
Deutsche Forschungsinstitute fur Textilindustrie
Reutlingen-Stuttgart
Institut fur Chemiefasern
7 Stuttgart-Wangen, Ulmer Strasse 227 (Germany)
(11 P. Rochas and J . C. Martin, Bull. Inst. Textile France 83, 41
(1959).
[2] B. Marek and E. Lerch, J. SOC. Dyers Colourists 81, 481
(1965).
[3] F. Sommermann, unpublished.
[4] F. H . Steiger, Textile Res. J. 27, 459 (1957); see also [I].
Aromatic Sigmatropic Rearrangements
By Hans Schmid [ *I
Aromatic sigmatropic rearrangements are thermal reactions
whose transition states can, to a first approximation, be
considered as interaction complexes between two pseudoradical halves that have arisen by homolysis of the bond that
is attacked. At least one of these halves must be aromatic in
nature, i.e. its x-system is to be described by aromatic molecular orbitals. A well-known example is the thermal Claisen
rearrangement of ally1 aryl ethers that occurs with inversion
Angew. Chem. internat. Edit.
Vol. 7 (1968) 1 No. 9
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