вход по аккаунту


Formation of Coordination Complexes in Anhydrous Acetonitrile.

код для вставкиСкачать
Formation of Coordination Complexes
in Anhydrous Acetonitrile
V. Gufmann, Vienna (Austria)
Chloride or azide ions were added gradually to solutions of
anhydrous perchlorates, tetrafluoroborates, hexafluoroantimonates, and hexachloroantimonates of Ti38, V3@, VO2@,
Cr3@, MnZ0, and Fe3@ in anhydrous acetonitrile. The formation of coordination complexes was followed by spectrophotometric, potentiometric (silver/silver azide electrode),
and conductometric methods. With the azides, the following
complex species were identified:
With chloride ions, on the other hand, the tetrachloro complexes were the highest formed:
Tic13 and [TiC14]e
vCL3 and [VC141Q
[CrClz]@,CrC13, and [CrC14]@
The formation of complexes of SbC15, SnC4, TiC14, BC13,
AlC13, GaCI3, InCl3, BBr3, AIBr3, GaBr3, and BF3 with
and ptrans-azobenzene, p-dimethylaminoazobenzene,
methoxyazobenzene was examined spectrophotometrically in
anhydrous acetonitrile. The equilibrium constants were
determined and the validity of the Hammett equation
established. A few of the complexes ,could be isolated. The
results of infrared spectrographic studies made it possible to
fix the position of the -N=N- vibration in azobenzene derivatives.
[Lecture at Bonn (Germany), July 20th, 19651
[VB 954/255 IE]
German version: Angew. Chem. 78, 151 (1966)
Structural Investigations on New Mercury
K. Brodersen, Erlangen (Germany)
Addition of methylamine to ethereal or benzene solutions of
mercury(I1) chloride or bromide leads to precipitation of the
compounds HgX2.2 NHzCH3 and HgXyNH2CH3 (X = CI
or Br). The former are converted into stable, pure compounds
HgXyNHzCH3 on treatment with the pure solvent or with
a solution of the mercury(1L) salt. The 1:2 adducts also lose
amine on thermal degradation, whereas the monoadducts
sublime unchanged. The compound HgClyNH2CH3 contains
four molecules per unit cell, and the following lattice constants were found for single crystals: a = 15.05 A; b = 5.81 A;
c = 5.72 A ; p = 97
Dimethylamine gives 1 : 2 adducts from benzene solution,
but only the 1 : l adducts from ether. Under the same
conditions trimethylamine gives only the adducts 3 HgXy
2 N(CH3)3, which can occlude HgX2. Daylight or ultraviolet
irradiation decomposes these adducts with production of
mercury(1) compounds.
Primary aliphatic amines (ethyl-, n-propyl, n-butyl-, and
n-pentyl-amine) give the substitution products Hg3(RN)zXz
alongside the 1 : 1 and 1 :2 adducts, the relative amounts
depending on the solvent used.
[Lecture at Marl (Germany),
October 13th, 19651
[VB 959/266 IE]
German version: Angew. Chem. 78, 151 (1966)
The chemisorption of nitrogen on various surfaces of tungsten
single crystals at room temperature and below was investigated by T. A . Delcher and G . Ehrliclz by measurement of the
contact potentials against platinum (platinum does not
adsorb nitrogen at room temperature). The work function for
electron emission from tungsten is reduced by chemisorption
of nitrogen o n the (100) surface by 0.4 eV, for the nitrogen is
present in the atomic state. The work function is increased by
0.15 eV o n the (111) surface; here some of the nitrogen is
adsorbed as atoms, some as molecules. At low pressures (ca.
10-7 mm) and room temperature the (110) surface does not
adsorb nitrogen; adsorption occurs only at lower temperatures (ca. 130 O K ) or at relatively high pressures (10-3 mm).
Here too the adsorbed nitrogen is atomic but is attached
differently from that on the (100) surface; the work function
is lower than that of the pure surface. / J. chem. Physics 42,
[Rd 3641573 IE]
2686 (1965) / -Hz.
Benzene is synthesized from acetylene in Avocado pears.
E. F. Jarisen and J . M. Wallace kept the unripe fruit for 4 h
in an atmosphere of [14C]acetylene. Four-fifths of the absorbed radiocarbon recurred in the respired carbon dioxide,
the remainder was incorporated into several compounds in
the fruit. Of these, 25 % were non-volatile and 30% was benzene with a specific activity of 0.5 % of that of the acetylene.
Another radioactive product identified was toluene. The
benzene was identified by converting it into P-benzoylpropionic acid, benzoic acid, and p-phenyl phenacylbenzoate, the
toluene analogously. / J. biol. Chemistry 240, 1042 (1965) /
[Rd 374/583 IE]
The oxidation of tungsten at 1400 to 3150’K has been
followed mass-spectrometrically by P. 0. Schissel and 0. C.
Trulson. The principal oxidation products are W3Og. W206,
WO3, and W02, the ratio depending on the oxygen pressure
and on the temperature of the metal surface. The observations can be explained by a reaction scheme involving two
oxygen species bound firmly to the surface. / J. chem. Physics
43, 737 (1965) / -Hz.
[Rd 397/606 IE]
The reactivity and function of the thiol groups of alcohol
dehydrogenase from horse-liver have been studied by 2‘. L. Li
and B. L. Vallee. The alcohol dehydrogenase (ADH) can be
inhibited by iodoacetate, two of the 24 thiol groups being
carboxymethylated. The other 22 groups react much less
readily; after denaturation, however, the reactivities of all
the thiol groups are the same. DPNH protects the A D H
against inhibition and carboxymethylation. The inhibited
and dicarboxymethylated A D H still interacts with DPNH
and alcohol, as can be seen from the rotatory dispersion and
the spectrum. Thus the two most reactive thiol groups are
not required for the binding of the coenzyme and the substrate. However, the dissociation constant (at p H 7.5) of the
complex of carboxymethylated ADH with DPNH is increased to 4x 10-5 (native enzyme with DPNH:4x 10-7). The
exchange of enzyme-bound 6sZnz+ with Zn2+ is faster, the
“half-life” under the conditions used being 20 hours for the
native enzyme and 14 hours for the carboxymethylated
enzyme. / Biochemistry 4 , 1195 (1965) / -HO.
[Rd 402/61 I IE]
Angew. Chem. internot. Edit.
/ Vol. 5 (1966) / No.
Без категории
Размер файла
131 Кб
coordination, formation, acetonitrile, complexes, anhydrous
Пожаловаться на содержимое документа