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Dibenzo[a e]cyclooctene Complexes of Chromium and Molybdenum.

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FXeOTeF5, like XeFz (31, can give up a fluoride ion to acceptors such as AsF5:
FXeOTeF5 -1 AsF5 + [FST~OX~]+[ASF&
Reaction of FXeOTeF5 with CsF proceeds via two routes in
almost equal proportions:
FXeOTeFs
+ CsFf
TeF6 + (FXeO-Cs+) --f CsF
+ Xe +
'/202
Complex (3) is apparently more stable than (2). That the latter
is formed first under mild conditions shows that less activation energy is required for complex formation of chromium
with the olefinic x-electrons of ligand L (it is not necessary
to compensate for the loss of resonance energy).
Heating this product (3) for 20 hours with a large excess of
Cr(CO), in di-n-butyl ether enables a further Cr(CO), group
to be introduced, thereby giving the orange, non-sublimable
~-dibenzo[u,e]cyclooctene-bis[tricarbonylchromium(0)],
LCrz(C0)6 (4). which can be purified in the same way as (3)
(decomp. above 170 "C).
XeFz t Cs[OTeFd
Experimental:
All reactions were followed gravimetrically and tensimetrically in easily weighable Kel-F reaction vessels fitted with
Kel-F taps. Vacuum manipulations were carried out in a
Monel system. The XeFz used in the experiments was prepared photolytically 141. Reaction of 2.35 g (13.9 mmole) of
XeF2 with 3.33 g (13.9 mmole) of HOTeFS yields 5.20 g of
FXeOTeF5, yield 96 %.
Received: January 10, 1969
[ Z 960 IE]
German version: Angew. Chem. 81, 330 (1969)
[*I Dr. F. Sladky
Institut fur Anorganische und Analytische Chemie
der Universitat
A-6020 Innsbruck, Innrain 52a (Austria)
[l] N . Bartlett and F. Slndky, unpublished.
[2] A . Engelbrecht and F. Sladky, Mh. Chem. 96, 159 (1965).
[3] F. Sladky, P. A . Bulliner, N . Bartlett, B. G. DeBoer, and A .
Zalkin, Chem. Commun. 1968, 1048.
141 S. M. Williamson, F. Sladky, and N . Bartlett, Inorg. Syntheses
11, 147 (1968).
Dibenzo[u,e]cyclooctene Complexes of
Chromium and Molybdenum
Treating an excess of tris(acetonitri1e)tricarbonylmolybdenum(0) I41 with L in dioxane at 35 'C/15 torr for 2 hours
gives a 65 % yield (calculated on L) of tetracarbonyl(dibenz0[a,e]cyclooctene)molybdenum(0), LMo(C0)4 / 5 ) , which
forms pale greenish-yellow crystals of m.p. 170 "C (decomp.).
It has not yet proved possible to convert this into a complex
analogous to ( 3 ) ; instead, heating it in di-n-butyl ether for
6-8 hours leads to separation of decomposition products and
formation of the lime-green cis-dicarbonylbis(dibenzo[a,e]cyclooctene)molybdenum(O), cis-LzMo(CO)z ( 6 ) , m.p.
215 OC (decomp.). The contrasting behavior of chromium
and molybdenum expresses clearly the differing tendencies
of these metals to formation of x-aromatic and x-olefinic
complexes.
By J. Miiller, P. Goser. and M. EIian[*l
Most of the x-aromatic complexes of chromium are considerably more stable than its x-olefin complexes. For instance,
reaction of Cr(C0)6 with 1,4-diphenylbutadiene leads exclusively to tricarbonyl(l.4-diphenylbutadiene)chrornium(O)
( I ) [1,21.
(I)
The constitutions of the new complexes were proved by
elemental analyses, mass spectra [61, the number and positions of the vco vibrations, and the IH-NMR spectra
(Table).
~~
For steric reasons the olefinic x-electron system of dibenzo[a,e]cyclooctene [31 (= L) seems to be considerably better able
to form complexes with chromium than is that of butadiene,
and by its use we have been able to provide the first example
of x-aromatic and x-olefin complexes from one ligand.
If the compound (L) is treated with tris(acetonitri1e)tricarbonylchromium(0) [41 in 5-6-fold excess in di-n-butyl ether
for 2 hours at 40 OC at water-pump vacuum and the ether is
then removed and the residue eluted with warm hexane, the
resulting solution affords crystals of the yellow tetracarbonyl(dibenzo[u,e]cyclooctene)chromium(O), LCr(C0)4 (2), m.p.
141-143"C, in 90% yield (calculated on L). This can be
sublimed almost without decomposition at 80-100 "C in a
high vacuum and is thermally more stable than tetracarbonyl(1,5-cyclooctadiene)chromium(0)~5~.However, when heated
in n-decane or di-n-butyl ether at 140°C, (2) loses CO during
1.5 hours to form yellow tricarbonyl(dibenzo[a,e]cyclooctene)chromium(O), LCr(CO)3 ( 3 ) , m.p. 168-17OoC, that
is purified by chromatography on silicagel in benzene and
recrystallization from rnethylene chloridejhexane.
374
Assignment
Compound
2.73
3.08
2
1
a
b
2.88
4.70
2
1
a
2.65
3.12
2
1
a
3.29
4.35
1
C
2
d
b
b
4.26
3.23
2
a
(4)
1
b
(5)
2.85
4.23
2
1
a
b
[a] In deuterioacetone.
Angew. Chem. internat. Edit.
I Vol. 8 (1969) I No. 5
The following are among the characteristic ions appearing in the mass spectra: ( 4 ) : LCrz(C0)6' (Ire1 = 12).
LCrz(C0)4+ (1.5), LCr2(CO)3+ (21), LCr2(C0)2+ (2.8).
LCrZCO+ (3.2). LCr2+ (14), LCr+ (85), Cr' (100); ( 6 ) :
LzMo(C0)z' (Ire1 = 9.2), L~MoCO' (28), L ~ M o + (28),
LMo' (loo), Mo+ (2.3).
lent cyciopentadienyl rings, whereas in the case of (3c) and
(3d) in the conformationally rigid state two separate 1H-NMR
signals for one axial and one equatorial cyclopentadienyl
ligand - as have been observed [31, even at room temperature,
for ( 1 ) - are t o be expected.
The IR spectra of the compounds in hexane solution included
the following absorptions in the vco region (in cm-1): (2):
2037. 1961,1916; ( 3 ) :1980,1913; ( 4 ) : 1980, 1913; ( 5 ) : 2050,
1975, 1965, 1915; ( 6 ) : 1978, 1940.
Received: January 16, 1969
[ Z 961 IEJ
German version: Angew. Chem. 81, 331 (1969)
0Ma
[*] Dr. J. Muller, Dip1.-Chem. P. Goser, and
Dip1.-Chem. M. Elian
Anorganisch-Chemisches Laboratorium
der Technischen Hochschule
8 Munchen 2 , Arcisstrasse 21 (Germany)
[l] M . Cais and M . Feldkimel, Tetrahedron Letters 1961, 444.
121 T. A. Manuel, S . L. Stafford, and F. G. A . Stone, J. Amer.
chern. SOC.83, 3597 (1961).
[3] M . Avram, D. Dinu, G. Mateescu, and C. D. Nenitzescu,
Chem. Ber. 93, 1789 (1960).
I
M
.
. Augl, Inorg. Chem. I,
141 D . P. Tate, W . R. Knipple, and .
433 (1962).
151 E. 0. Fischer and W . Frohlich, Chem. Ber. 92, 2995 (1959).
[6] Atlas-CH4; ion source T04; 50 eV.
S.
13ai
13bl
13cl
13dl DEl
The IH-NMR spectrum of ( 3 ) . which was recorded for saturated solutions in acetone o r dimethyl disulfide with T M S as
external reference, contains only one sharp signal for the
C5H5 protons at T = 5.25 (in acetone) or 4.78 (in dimethyl
disulfide) at room temperature, even with scale expansion,
and this signal shows no splitting when the sample is cooled
down to -95 O C (in acetone) [a].
Since the angle of twist 3s-S-S-S of 75-100 [91 necessary
for stable sulfur rings can, moreover, only be realized in
(3b) and ( S c ) , it is probably the conformer (3b) that is
present in solution at sufficiently low temperatures.
Bis(cyclopentadieny1) tetrasulfdomolybdenum( IV) ( 3 )
A Tetrasulfide Chelate of M o l y b d e n u m r l l
By H. Kopf[*l
The few polychalcogenide chelates of platinum [21 and titanium[31 that have become known up t o the present time all
contain six-membered metal-chalcogen rings ("heterocyclohexachalcogens"). Thus, for example, attempts t o prepare
the four- and five-membered rings (C5H&TiS3 and
(C5H5)2TiS4[41 always led to the stable six-membered ring
(CsH&TiS5 ( I ) [XI.
However, when we treated dichlorobis(cyclopentadieny1)molybdenum(1v) (2) with ammonium pentasulfide we obtained, not the expected [61 pentasulfide, but the tetrasulfide
chelate (3) and thus the first simple hetero derivativeI71 of the
still unknown cyclopentasulfur.
The composition [(CsHs)zMoS& of ( 3 ) follows from complete elemental analysis; according to ebullioscopic molecular-weight determinations in acetone n = 1. Compound ( 3 )
crystallizes from acetone as dark red, air-stable prisms that
decompose slowly above 18OOC and rapidly at 25OOC. I t is
less soluble than ( I ) in organic solvents and the absorption
of its orange t o bright red solutions exhibits a hypsochromic
shift (absorption shoulder at 400 nm).
The I R spectrum of ( 3 ) [KBr disk; cm-1: 3100s (VCH);
1430 vs, 1410 VS, 1350 W, 1120 VW, (WCC); 1075 w, 1063 w,
1012 m, 1000 s (a&;
954 vw, 926 vw, 872 m, 832 vs, 822 vs
(YCH); 482w (ass?)] shows the vibrations of the intact
(X-C~H&MOIVsystem. The band at 482 cm-1 is tentatively
assigned t o a S4 skeletal vibration.
Of the four ideal conformations (3a-d) that are conceivable
for a MoS4 five-membered ring, ( 3 n ) and (36) have equivaAngew. Chem. internat. Edit. / Vol. 8 (1969) No. 5
Bis(cyclopentadienyl)dihydridomolybdenum(Iv) ( 4 ) [101(2.3 g.
10 mmole) is refluxed for 3 h with chloroform (150 ml) in the
absence of light and with exclusion of air and moisture to
yield compound (2) [111. After removal of the excess of chloroform under vacuum, the olive green residue is treated with
150 ml of a saturated solution of freshly prepared ammonium
pentasulfide
in water/ethanol (1:s v/v) and refluxed for
1 h with vigorous stirring. The reddish brown precipitate is
filtered off, washed with ethanol, and recrystallized from
acetone. Yield 3.1 g (88 % calculated with respect t o ( 4 ) ) .
Received: January 22, 1969
[Z 962 IE]
German version: Angew. Chem. 81, 332 (1969)
~~~
[*I Dr. H. Kopf
Institut fur Anorganische Chemie der Universitat
87 Wurzburg, Rontgenring 11 (Germany)
[l] Part 3 of Organometallic PolychalcogenideChelates. -Part 2:
H. KOpL Chem. Ber., in press.
[2] P. E. Jones and L. Katz, Chem. Commun. 1967, 842.
[3] H. KopL B. Block, and M . Schmidt, Chem. Ber. 101, 272
(1968).
[4] R. Ralea, C. UngurenaSu, and $. Cihodaru, Rev. roum. Chim.
12, 861 (1967).
[5] Compare Part 2 of this series, cited in reference [l], as well as
Part 1: H. Kopf and B. Block, Chem. Ber., in press.
[61 H. Kopf and B. Block, Progr. coordinat. Chem., Proc. 11th
International Conference on Coordination Chemistry, Haifa and
Jerusalem 1968, 337.
[7] It has recently proved possible to establish a chelate-type coordinate bond between macrocyclic organotetrasulfide ligands
and nickel; cf. N. B. Egen and R. A. Krause, J. inorg. nuclear
Chem. 31, 127 (1969).
[8] Thanks are due to Dr. D. Scheutzow, Universitlt Wurzburg,
for recording the low-temperature NMR spectrum.
[91 J . Donohue, A. Caron, and E. Goldish, J. Amer. chem. SOC.
83, 3748 (1961); A. Caron and J. Donohue, Acta crystallogr. 14,
548 (1961).
[lo] M . L. H . Green, J. A. McCleverty, L. Pratt, and G. Wiikinson, J. chem. SOC.(London) 1961, 4854.
[ I l l R. L. Cooper and M . L. H. Green, J. chem. SOC.(London)
A 1967, 1155.
[121 G. Brauer: Handbuch der Praparativen Anorganischen
Chemie. 2nd Edit., Vol. I , F. Enke, Stuttgart 1960, p. 335.
375
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