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CnCe-Coupling of Two {(CO)5CrCNEt2} Fragments by Reductive Dimerization of a Cationic Carbyne Complex.

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Vacuum Pyrolysis of
111 E. V.
5,5,10,10-TetrachIorotricyclo~,7diene: 1,5- and 2,6-Dichloroazulenes**
By Eckehard V. Dehmlow* and Marion Slopianka
The dehalogenation of tetrahalotricycl0[]decadienes with organolithium compounds leads via meso1,2,4,6,7,9-~yclodecahexaene
to naphthalene[''. However,
nothing has been described in the literature about the thermolysis and dehydrohalogenation of such compounds,
whereas the related bicyclo[6. I.O]nonatrienes found much
Cleavage of HCI takes place to a small extent on sublimation of the title compound 1 in a "poor" vacuum
(250"C/100-200 torr); on heating to 170°C in quinoline,
it undergoes polymerization. 1 behaves similarly in the
presence of NaOCH3 in HOCH,['I.
- cba
c1 \
Dehmlow, G. C. Ezimora, Tetrahedron Lett. 1970. 4047; E. V.
Dehmlow, M. Lissel, Liebigs Ann. Chem. 1979. 181.
[21 E. V. Dehmlow, H. Klabuhn, E.-Ch. Hass, Liebigs Ann. Chem. 1973.
I31 G. Seybold, Angew. Chem. 89 (1977) 377: Angew. Chem. Inr. Ed. Engl. 16
(1977) 365.
[41 a) 2, m.p. 89°C; UV (ether): 772 nm (Ig&= 1.99). sh 724 (2.07), 692.5
(2.39), sh 654 (2.40), 631 (2.47), sh 608 (2.41). 368 (3.76), 351 (3.73), 285
(4.60), 232.5 (4.20): 'H-NMR (DCCI,): 6=8.34 (d, J = 2 . 2 Hz), 8.30 (d,
J = 10). 7.8 (d, J=4.2), 7.75 (dd, J = 10+2.2), 7.27 (d, J=4.2), 7.05 (dd,
J = l o + 10); b) 3, m.p. 139-140°C; UV (ether): sh 640 nm (Ige=2.02),
586 (2.41). 551 (2.46), 368 (3 70). 353 (3.68), 338 (3.57), 3 I I (3.66). 289
(4.86), sh 280 (4.80), 233.5 (4.21): ' H - N M R (DCCI,): 6=8.00 (d, J = I I
Hz), 7.34 (d, J = I I)(both with further slight splitting), 7.24 (5) in the ratio
[51 C.Boche, H. Weber, J. Benz, Angew. Chem. 86 (1974) 238; Angew. Chem.
Inr. Ed. Engl. 13 (1974) 207.
C,C,-Coupling of Two {(C0)5CrCNEt2}Fragments
by Reductive Dimerization of a Cationic Carbyne
By Ernst Otto Fischer*, Dieter Wittmann.
Dieter Himmelreich, and Dietmar Neugebauer
We have now carried out a flash pyrolysis of 1 at ca.
700"C/10-4 torr in the apparatus described by Seybold3l.
The blue product was free of educt. Preparative thin-layer
chromatography on silica gel with petroleum ether as
eluent afforded a deep-blue zone and a blue-violet zone,
from which two CloH6C12-isomerswere obtained. In addition, traces of 2,6-dichloronaphthalene (but not the 1 5
isomer!) were detectable. A diffuse, deep polar-blue zone
could not be obtained in a pure state.
The blue compound was shown by analysis and spectral
data to be 1,5-dichloroazulene 2[4i11
the blue-violet compound to be 2,6-dichloroazulene 3[4b1.
These compounds, the first azulenes with halogen-substituents in both rings, are potentially interesting educts for
further syntheses.
Addition of nucleophiles to the carbyne carbon atom of
the cationic aminocarbyne complex [(CO),CrCNEt2]BF4
l r 2 I leads to numerous aminocarbene complexes
[(CO),Cr(C(NEt,)Nu}] not usually accessible via conventional routes. Thus, e.g., reaction of 1 with potassium diphenylarsenide affords the C,-arsene-substituted aminocarbene complex [(CO),Cr(C(AsPh2)NEt,}] 4[51.
A completely different type of reaction course is observed on reaction of 1 with lithium dimethylarsenide: Instead of the expected addition of nucleophile with formation of the complex analogous to 4, reductive C,C,-coupling of two ((CO)5CrCNEt2)fragments takes place to give
the p-bis(amin0carbene)-complex 5 (cu. 30% yield, elemental analysis, MS, IR, NMR, X-ray structure analysis).
2[(C0)5CrCNEt2]BF, + 2 LiAsMez
1 l .
[{(CO),CrCNEt,),] + AszMeJ + 2 LiBF,
For the formation of 2, we suggest dehydrochlorination
to 4, subsequent rearrangement to 5 , and renewed dehydrochlorination. 3 can be formed via Cope-rearrangement
to 6 and double dehydrochlorination. A reaction analogous to the intermediate formation of 6 is known in the
well-investigated bicyclo[6. I .O]nonatriene seriesI5l.
Received: January22, 1981 [Z I l l IE]
German version: Angew. Chem. 94 (1982) 461
[*] Prof. Dr. E. V. Dehmlow
Fakultat fur Chemie der Universitat
Postfach 8640, D-4800 Bielefeld I (Germany)
M. Slopianka
lnstitut fur Organische Chemie der Technischen Universitat
D-1000 Berlin (Germany)
[**I This work was supported by the Fonds der Chemischen lndustrie
0 Verlag Chemie GmbH. 6940 Weinheim. 1982
The tetramethyldiarsane formed concomitantly as oxidation product can be detected mass spectrometrically in the
form of the complex pentacarbonyl(tetramethy1diarsane)chromium(o). As a result of hindered rotation about
the C,-C& bond in 5, two conformational isomers are
formed whose existence in solution is demonstrated both
by IR data as well as 'H-NMR data.
An X-ray structure analysis of 5 showed that the two
((CO)5CrCNEt2)fragments are crystallographically connected via a C,-axis. The p-bis(amin0carbene)-complex,
however, with the longest Cr-Ccarbene bond length
(219.0(7) pm)l6] found so far, shows no shortening of the
C,-C& (148.0(9)pm) and C,-N
(130.6(9) pm) bonds. The
angle of 97.6" between the two carbene fragments
and Cr*-C,,-N*-C,
rules out a
bridging delocalized n-sy~tem"~.
Each metal atom balances
its charge by a significant shortening of its bond distance
to the /runs-carbonyl group (Cr-C1 184.8(10)pm).
[*] Prof. Dr. E. 0. Fischer, D. Wittmann, D. Himmelreich,
Dr. D. Neugebauer
Anorganisch-chemisches Institut der Technischen Universitat Munchen
Lichtenbergstrasse 4, D-8046 Garching (Germany)
0~570-0833/82/0606-0444LE 02.50/0
Angew. Chem. Inr. Ed. Engl. 21 (1982) No. 6
Apart from 1 only the intense red-orange compound 6
is isolated, whose structure was determined by X-ray diffraction.
c 1L
Fig. I. Molecular structure of p-[1,2-bis(diethylamino)ethanediylidene]bis(pentacarbony1chromium) 5 in the crystal.
= P?'
C Me,
We presume that by analogy with the [2+ l]cycloaddition of 1,2-bis(tert-b~tyl)iminophosphane~~~,
two molecules
of 5 react to give 1 and a carbene diazasilacyclopentenylidene, which dimerizes to 6.
In the meantime we have also been able to demonstrate
the formation of 5 in the reaction of 1 with lithium acetylacetonate; the compound is likewise formed as by-product
in the aforementioned synthesis of 4.
This novel type of reaction-reductive dimerization of a
cationic carbyne complex with C,C,-coupling-can
become the dominating reaction competing against addition of the nucleophile to the carbyne carbon atom when
using strongly reducing nucleophiles.
The carbene-analogous behavior of the phosphorus in 5
could result from its increased nucleophilicity produced
by the tert-butyl group.
Received: March 5, 1982 [Z 123 IE]
German version: Angew. Chem. 94 (1982) 451
The complete manuscript of this communication appears in:
Angew. Chem. Suppl. 1982, 1036-1047
Received: January 29, 1982 [Z 121 IE]
German version: Angew. Chem. 94 (1982) 461
The complete manuscript of this communication appears in:
Angew. Chem. Suppl. 1982. 1009-1015
[ I ] Transition Metal-Carbyne Complexes, Part 70. This work was supported
by the Fonds der Chemischen 1ndustrie.-Part 69: E. 0. Fischer, V. N.
Postnov, F. R. Kreissl, J . Organomel. Chem., in press.
[2] E. 0. Fischer, W. Kleine, F. R. Kreissl, Angew. Chem. 88 (1976) 646; Angew. Chem. Inl. Ed. Engl. 15 (1976) 616.
[5] U. Schubert, E. 0. Fischer, D. Wittmann, Angew. Chem. 92 (1980) 662:
Angew. Chem. Inl. Ed. Engl. 19 (1980) 643.
[6] E. 0. Fischer, D. Himmelreich, R. Cai, H. Fischer, U. Schubert, B. Zimmer-Gasser, Chem. Ber. 114 (1981) 3209.
171 U. Schubert, J. Organomel. Chem. 285 (1980) 373.
121 M. Baudler, Pure Appl. Chem. 52 (1980) 755.
171 M. Hesse, U. Klingebiel, unpublished results.
[8] E. Fluck, Top. Phosphorus Chem. 10 (1980) 193: R. Appel, F. Knoll, J.
Ruppert, Angew. Chem. 93 (1981) 771: Angew. Chem. Int. Ed. Engl. 20
(1981) 731.
[9] E. Niecke, R. Riiger, Nachr. Chem. Tech. Lab. 29 (1981) 11, 754.
[lo] 1, yield 30%, m.p.= 116"C/0.01 torr, MS (70 ev): m / z 358 (35%, M + ) :
"P-NMR (in C6Ha,
H3PO4int.): 6 = -93.3 (P,,), - 101.5 (Ps), J,,r=206
1111 6 , yield =15°/o, m.p.=147"C, MS (70 ev): m / r 364 (6O%, M + ) : 'HNMR (in C6HhrTMS int.): 6=0.39 (SiMe2), 1.37 (IBuN), 2.28 (CMe).
A Spirocyclic Diphosphirane**
By William Clegg, Martin Haase, Michael Hesse,
Uwe Klingebiel, and George M. Sheldrick*
Stable cyclotriphosphanes, as well as mono- and diphosphiranes"] are known. We describe here the spirocyclic diphosphirane 1 obtained by a novel routel'"].
Structure of the Octabismuth(2
Crystalline Bi8(AIC1&
+ ) Cluster in
By Bernt Krebs*, Marita Hucke. and Claus Jorg Brendel
Three unusual polycations of the heavy main group element bismuth-Bi:+,
Bii+, and Bi;+-have so far been
described in the literat~re[~-'I,
of which only the Big' cluster ion has been unequivocally characterized by X-ray
structure determinations on BiloHf3C118[61
and Biz4C1,,[41.
Although solid compounds of the composition
and Bi4(AIC14)151
have been isolated, preparative difficulties with respect to the synthesis of pure single crystal phases have prevented a similar structural proof
of the postulated pentameric and octameric cations. The
Bi;+ cluster (22 valence electrons, Bi with the very low oxidation number + 0.25), whose degree of association in the
chemistry of the "naked" metal cluster is still without example, seems particularly interesting. We have now been
able to prepare this species in the form of pure Bi8(AIC14)2
In the reaction of lithiated 2 with tert-butyldichlorophosphane, phosphino-substituted 4 can be detected in solution. Attempts to distil 4 result in continuous loss of
chlorotrimethylsilane; the
methylenephosphane 5 could not, however, be detected.
[*] Prof. G. M. Sheldrick, Priv.-Doz. Dr. U. Klingebiel,
Dr. W. Clegg, M. Hesse, M. Haase
Institut fur Anorganische Chemie der Universitat
Tammannstrasse 4, D-3400 Gottingen (Germany)
[**I This work was supported by the Deutsche Fonchungsgemeinschaft and
the Fonds der Chemischen Industrie.
Angew. Chem. Int. Ed. Engl. 21 (198.2) No. 6
[*I Prof. Dr. B. Krebs, Dip[.-Chem. M. Hucke, C. J. Brendel
Anorganisch-Chemisches Institut der Universitat
Corrensstrasse 36, D-4400 Miinster (Germany)
0 Verlag Chemie GmbH. 6940 Weinheim. 1982
OS70-0833/82/0606-0415 $. OZ.SO/O
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two, complex, dimerization, couplings, reductive, fragmenty, carbyne, cationic, cnce, 5crcnet2
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