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Nickel(0)-dialkylcyanamide-carbonyl.

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crystalline form in a yield of about 75 % [I]. Gaseous
reaction products are a little ethylene, but chiefly ethane and
hydrogen. Therefore, the reduction proceeds, at least partially, as follows:
Nickel(0)-dialkylcyanamide-carbonyl
(CsH70z)
Institut fur Anorganische Chemie
der Universitat Miinchen (Germany)
a) Ni(CsH702)z
Ni(C2HS)z
NiHz
By Dr. H. Bock
/
+ 2 AI(CZHS)ZOCZHS+ Ni(CzH5)z + 2 A1-0C2Hs
-
NiHz
+
\
+ 2 CzH4
CzHs
N i + Hz
The evolution of ethane may arise from a side reaction
hydrogenation of ethylene or from radical formation by decomposition of the intermediate Ni(CzH& :
The yield of (TPP)zNiC2H4 can be raised to 90-95 % if a
solution initially saturated with ethylene is employed. Molecular weight determinations in benzene showed that the
compound is monomeric in solution, i.e. it behaves again as
a nickel complex of coordination number 3 [2]. Similarly, the
following compounds (R3P)zNi.C2H4were prepared :
R
I Yield [%I 1 Form
Ethyl
Cyclohexyl
I
I
70
92
Yellow oil
Yellow crystals
Nickel(0)-dialkylcyanamide-carbonyls (1) are formed by the
reaction of dialkylcyanamides with an excess of Ni(C0)4
as analytically pure, air-sensitive orange coloured crystals:
Ia, R = CH3, Decompn. pt. 98'C; Ib, R = -(CH2)5-.
Decompn. pt. 118 "C.
(1)
The structure follows from elemental analysis, molecular
weight determination, diamagnetism and infrared spectra [I]
between 2300 and 1700 cm-1. There are three equally strong
bands (la: 2037(a), 2004(b), and 1790(c) cm-1; Ib: 2037(a),
1980(b), and 1790(c) cm-1). These bands can be attributed to
the N-C-N
skeleton, the vibrations of which are shifted to
lower frequencies by complex formation (a and b), and to the
bridge carbonyl group (c). The nitrile bands of the free
cyanamides occur at 2217 cm-1
An additional confirmation of the proposed structure is
provided by the quantitative thermal decomposition at
10-4 mm Hg :
[Ni(RzNCN) (CO)]z + 2 N i
+ 2 RzNCN + 2 CO
Received, August 1st. 1962
Yellow, crystalline compounds.
Ethylene is expelled by the action of other electron donors.
By volumetric determination of ethylene the progress of the
expulsion can be followed. In all cases over 90 % of ethylene
are obtained.
By splitting-off ethylene from (TPP)2NiC2H4 according to
the general equation:
c) (TPP)zNiGH4
+ Donor + (TPP)zNi.Donor + C2H4
the following crystalline compounds were obtained among
others:
[Z 320/164 IEI
[l] For a discussion of the infrared spectra I am indebted to Dr.
H. P. Fritz; the magnetic measurements were carried out by
cand. phys. H. M6dI, Physikalisches Institut der Technischen
Hochschule Miinchen.
The Intermediate Product of the Wackenroder
Reaction
By Prof. Dr. P.W. Schenk and cand. chem. W. Kretschmer
Institut fur Anorganische Chemie
der Freien Universitat Berlin (Germany)
According to present concepts the treatment of H2S with SO2
in aqueous medium results in two simultaneous reactions:
1)
2)
88 %, yellow orange
The formation of the different polythionic acids can be
interpreted by the equation:
I
3)
90 %, yellow, crystallizes
with 1 molecule of benzene
Investigations are in progress on the infrared and proton
resonance spectra of the described new compounds to
determine the effect of different donors on the bond between
nickel and the CCC multiple linkages.
Received, July 27th. 1962
[Z 316/150 IE]
11) Previously, this compound was erroneously considered to be
[(C~HS)~P]~N~(O):
G. Wilke, E. W. Miiller, and M. Kroner, Angew.
Chem. 73, 33 (1961).
[2] G. Wilke, Angew. Chem. 72, 581 (1960).
550
+
83 %, dark red
C6Hs
60 %, yellow
2 H z S + SO2 + 3 S + 2 H 2 0
HzS 3 SO2 + H2S4O6 (HzS,06)
+
H~S40.5 HzSOJ
+ H2S3Os + HzSzO3
Whereas it is generally accepted that equation 3 is valid,
opinions regarding the initial reactions differ [I]. Since a
major role is sometimes attributed [2] to the sulphur formed
according to equation 1, we tested whether it is in fact
elementary sulphur that precipitates in the reaction of H2S
with SOz. The remarkable golden-yellow colour of the
precipitate could be due to polysulphur oxides [3,4], although monomeric S20 is extremely sensitive to water [5].
We passed H2S into an ice-cold solution of sulphurous acid
to which some NaCl and HCl had been added to permit a
ready flocculation. The golden-yellow precipitate was sucked
off quickly and dried in high vacuum. It was then decomposed
it by quick heating. The abundantly evolved gases, which
were pumped off, condensed in liquid air to a cherry red
condensate. The ultraviolet spectrum of the gases showed
the bands of S20.
Angew. Chem. internat. Edit. 1 Val. I (19621 / No. I0
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