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Cycloadducts from Trichloroallenyllithium.

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Structure of Dhethylnitrosaminecopper(r1)
Chloride [ I I
By U. Klement and A . Schmidpeter~*1[21
Nitrosamines form addition compounds with metal halides
and non-metal halides. Potentially each of the three atoms of
the nitrosamine skeleton possesses a donor function. In the
case of halides having a prominent Lewis acid character coordination of the amino nitrogen was first assumed [31; later,
1H-NMR spectroscopic studies revealed coordination of the
nitroso oxygen atom [41. The IR spectra of nitrosamine complexes of the transition metal halides likewise indicate the
presence of bonding to the oxygen atom 14.51; however, the
nature of the bonding is unclear as yet since the stoichiometry
of the 1:1 complexes with metal(1r) halides suggests that they
contain the nitrosamine not only as unidentate ligand.
We have examined X-ray spectrographically the well developed, but easily cleavable, red crystals of (CH3)2N-NOCuCI2
( I ) . The lattice constants (in A) have the following values:
a = 6.376, b = 14.685, c = 7.265; the space grouping is
D&Pnam. According to the density, 2.07 g/cm3, the unit cell
contains four formula units. 730 reflections were measured
(counting tube) and corrected for absorption and the Lorentz polarization factor. Isotropic refinement of the values
by the method of least squares led to an R value of 15%;
further refinements are being carried out.
The structural skeleton is formed by slightly puckered CuC12
chains which run through the crystal parallel to the x-axis
and in which the copper atoms are coupled by double chlorine
The distance between neighboring chains is 7.34 A in the y direction and 3.6 A in the z-direction. I n the x-direction the
chains are shifted by about 0.5 A with respect to one another.
The nitrosamine molecules are perfectly planar and arranged
alternately on both sides of a chain and with the copper
atoms situated in the same plane paralled to (001). They
direct thereby the nitroso group, which is approximately
aligned with the axis of the chain, to the chain. The nitrosamine molecules of neighboring chains lie inverted above
each other. The planarity was first proved independently of
the space group symmetry, in that calculations were made for
the noncentrosymmetric sub-group Czv-Pna21. Further refinement and the reflection statistics showed a centrosymmetric space group and that all atoms except chlorine lie in
the mirror plane. The layer structure appears also in the extreme cleavability parallel to (001).
This formula also makes the weak bonding of the nitroso
nitrogen understandable; the use of its lone pair leads to
adjacent partial positive charges. The bond lengths of the free
dimethylnitrosamine are not known. The best indication is
provided by the values of methyl nitritecgl; if one considers
the spectroscopically verified stronger participation of the
free lone pair of the amino nitrogen then for the nitrosamine
N - 0 of 1.27 A and N-N of 1.37 A can be estimated. Compared with these values the N-N distance in ( I ) is, as expected, considerably shortened; remarkably, however, the N - 0
distance is also shortened.
Received: March 13, 1968
[Z 749 IE]
German version: Angew. Chem. 80, 444 (1968)
[*] Dr. U. Klement and Dr. A. Schmidpeter
Institut fur Anorganische Chemie der Universitat
8 Miinchen 2, Meiserstr. 1 (Germany)
[l] 3rd Part of Reactions of Nitrosamines with Electrophiles 2nd Part: [4].
[2] We thank the Deutsche Forschungsgemeinschaft for their
support of this work.
131 J . Goubeau, Angew. Chem. 73,305 (1961).
[4] A . Schmidpeter, Chem. Ber. 96,3275 (1963).
[5] R. D . Brown and G. E. Coates, J. chem. SOC.(London) 1962,
[6] J. A . J . Jarvis, Acta crystallogr. 15, 964 (1962).
171 D . Harker, Z. Krist. 93, 136 (1936); C. H. MacGillavry and
J. M. &wet, ibid. 94, 231 (1936).
[8] J. D. Dunitz, Acta crystallogr. 10, 307 (1957).
[9] F. Rogowski, Ber. dtsch. chern. Ges. 75,244 (1942).
Fig. 1. (CW)-Projection of two formula units of ( I ) with bond lengths (A)
and angles.
The structure found is,reminiscent of that of the 1,2,4-triazolecopper (11) chloride (2) [61. In both cases the copper atom
is approximately octahedrally surrounded by four chlorine
atoms and two donor functions of two molecule ligands
situated trans to each other. I n ( I ) the nitroso group appears
in place of the neighboring nitrogen atoms of the ring in (2).
In both cases the CuC12 chain is folded as a result of the bridging of the copper atoms via the lighting molecules. In detail,
however, the structures ( I ) and (2) are fundamentally different. In (2) and in the compound LZCuC12 (L = H2O 171,
pyridinec81) the chlorine atoms round a Cu atom form a
rhombus with two short Cu-CI distances of 2.28 to 2.34 A
and two long distances of 2.77 to 3.05 A; in ( I ) on the other
hand they form a square with uniformly short Cu-Cl
distances. Whilst in (2) two chlorine atoms lie in the direction
of the Jahn-Teller distortion, in ( I ) these positions are clearly
occupied by the donor atoms of the ligands. Correspondingly
the distances Cu-0 and Cu-N are here considerablv loneer
than in (H20)2CuC12 (with 2.01 A [7J)and in ( C ~ H ~ N ) ~ C U C I ~
(with 2.02 A [81).
However, the distance Cu-0 is shorter and the distance
Cu-N much longer than one would expect to be the case
along the axis of the Jahn-Teller distortion (both about
2.6 A). The bonding of the copper to the nitrosamine is
thus mainly via the oxygen. The nitroso nitrogen is equidistant from two neighboring copper atoms of a chain. The difference between the Cu-0 and Cu-N distance is made
possible by the fact that the Cu protrudes about 0.2 A from
the plane of surrounding chlorine atoms in the direction of
the oxygen. A transition from octahedral to square pyramidal environment is therefore suggested.
The complexed nitrosamine is best described by the limiting
formula (3).
Cycloadducts from TrichloroallenyUithiumIll
By G . Kobrich and E. Wagner[*]
Trichloroallenyllithium (3) is interesting as a homolog of the
known carbenoids ( I ) and (2) [21; further, lithioallenes have
hitherto been known only as intermediates 131.
We obtained stable solutions of (3) on treating trichloroallene
( 5 ) [41 or, better, 1,2,3,3-tetrachloro-l-propene
( 4 ) (cis and/
Angew. Chem. internat. Edit.
Val. 7 (1968) 1 No. 6
or trans)r51 with one or two molecular equivalents of nbutyllithium, respectively, in Trapp mixture 161 at -110 "C.
Trichloroallene ( 5 ) is metalated faster than it is formed from
( 4 ) , since only ( 4 ) is obtained alongside ( 3 ) if a sample of ( 4 )
is treated with less than 2 molecular equivalents of n-butyllithium. Carboxylation of ( 3 ) affords a mixture of dimeric
carboxylic acids in 90% yield. About half of this mixture
consists of (7) [41, which can be separated as the dimethyl
ester (m.p. 161.5-163.5"C) [71.Proof that formation of monomeric trichloroallenyllithium from ( 4 ) is almost quantitative
is provided by the diene reaction of the primary product ( 6 )
of carboxylation with cyclopentadiene (added a t -90 "C),
which gives a structurally homogeneous adduct C9H7C1302
of m.p. 141-143 O C [yield 91 % calculated o n the amount of
( 4 ) used]. Of the four theoretically possible isomers the iodolactone reaction[sl decides in favor of (8) since it gives the
tricyclic compound ( 9 ) (m.p. 157-158 O C ; v c - 0 = 1800
cm-1). In hot N a H C 0 3 solution compound (8) forms (10)
(m.p. 111-1 12 "C) instead of a tricyclene 181.
71-73 "C), which we consider to arise from the primary
product ( I 2 ) and an excess of (3) by way of the diallene (13)
with subsequent cyclization.
Compound (15) and cyclopentadiene give the adduct (14)
(m.p. 143-144.5"C), whose N M R spectrum shows different
T values (6.44 and 6.66,each a quartet with J = 1.8-2.0 Hz)
for the two bridgehead protons. This must be due to the influence of the ester group, which, therefore, is probably
spatially close to a bridgehead and thus assumes in (IS) a
position remote from the second exocyclic double bond.
Thermolysis of ( 3 ) , which begins at -9OoC, gives neither
tetrachlorohexapentaene nor the product of a dimerizing xelimination, and no cyclopropane derivative if cyclohexene
is added, but, instead, soot-like polymers are formed.
Preparation of ( 3 ) : A solution of 20 mmoles of ( 4 ) in 48 ml
of Trapp mixture is treated dropwise under NZ at - l l O ° C
within 10-15 min with 40 mmoles of n-butyllithium in
20 ml of petroleum ether, and the mixture is stirred for a
further 40-45 min at -110 "C.
Preparation of (8): Compound ( 3 ) is carboxylated with a n
excess of pre-cooled powdered dry-ice 191, 24 ml of distilled
cyclopentadiene is added and the mixture is allowed t o come
to room temperature within 24 h. On working-up by the
usual technique[9], 4.61 g (91 %) of (8). m.p. 141-143 O C
(after crystallization from CC14 and sublimation at 110"CI
1 torr), is obtained as acidic portion.
Received: March 22 and April 10, 1968
[Z 760a IE]
German version: Angew. Chem. 80, 481 (1968)
[*I Doz. Dr. G. Kobrich and Dr. E. Wagner
The deep violet color of trichloroallenyllithium indicates a n
ion-pair structure with the limiting forms ( I l a ) and ( I l b ) .
The reasonable ambivalence is realized, at least formally,
on treatment with methyl chloroformate which attacks at C-3
in contrast t o carboxylation; surprisingly, the sole defined
product is the unstable dimethylenecyclobutene (IS) (m.p.
Institut fur Organische Chemie der Universitat
69 Heidelberg, Tiergartenstrasse (Germany)
[l] Stable Carbenoids, Part X X X I L P a r t XXXI : G. Kobrich,
H . Trapp, and A . Akhtar, Chem. Ber. 101 (19681,in press. - We
thank Frau S . Schneider-Rincke, Frau A . Rissmann, and Fraulein
Dr. D . Krauss for measuring the spectra, and the Deutsche Forschungsgemeinschaft for financial support.
[2]Review: G. Kobrich et al., Angew. Chem. 79, 15 (1967);
Angew. Chem. internat. Edit. 6, 41 (1967).
[3]Cf. 0.V. Perepelkin, V. A . Kormer, and K . V. Bal'yan. Zhur.
organ. Khim. 2, 1747 (1966);0.V. Perepelkin and K . V. Bal'yan,
ibid. 2, 1928 (1966);Chem. Abstr. 66, 75592, 75593 (1967).
[4]A . Roedig and N . Detzer, Angew. Chem. 80, 482 (1968);
Angew. Chem. internat. Edit. 7, 471 (1968);A . Roedig, personal
communication (1965). - We thank Prof. Roedig for a sample of
the acid (7).
[5]J . M. Heilbron, R. N. Heslop, and E. Irving, J. chem. SOC.
(London) 1936, 78; H. J. Prins, Rec. trav. chim. Pays Bas 68,
898 (1949).
161 THF, ether, and petroleum ether (4:1:1) 191.
[7]Structures of new compounds are proved by analytical and
spectroscopic data.
[8]Cf. K . Alder, R. Hartmann, and W. Rorh, Liebigs Ann. Chem.
613, 6 (1958).
191 Cf. G.Kobrich and H. Trapp, Chem. Ber. 99,670.680 (1966).
- LiCl
c =c=c
cl/ ( I l b )
CI-C=C =c,
Angew. Chem. infernat. Edit.
Preparation and Dimerization of
/ Vol. 7 (1968) / No. 6
By A . Roedig and N . Detzer [*I
Treating 1,2,3,3-tetrachloro-l-propene ( I ) (cis and/or
trans) [21 in a propane-ammonia mixture with sodamide gives
trichloroallene (2) as an almost colorless liquid, which
gradually solidifies (yield 76.5 %). If recorded immediately
after removal of a sample from the cooling bath, the IR
spectrum (capillary layer) of this compound shows the bands
at 1940 and 760 cm-1 typical of a n allene, but warming causes
these t o change rapidly t o the bands of the dimers ( 3 ) and
( 4 ) . Undiluted (2) decomposes explosively at room temperature. In petroleum ether, dimerization is complete in 3 days
at 20°C.
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