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Structure of [(CO)5CrNEt2]BF4 a Key Organometallic Compound; Reaction to Give the Carbene Complex (CO)5CrC(AsPh2)NEt2.

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N-Fluoroiminosulfur Tetrafluoride, F-N=SF4[**1
By Darryl D. DesMarteau and Konrad SeppeltI'l
Oriented double bonds on sulfur(vi) tetrafluoride systems
Here we
open new theoretical and structural
present the simplest fluorinated sulfur(v1) imide.
~ N = S F ~
Starting with Cl2N-SF,r31, chlorofluoroaminosulfur pentafl~oride[~]
(b. p. 25.3 "C (extr.)) is prepared first, which in
turn is reduced by mercury in trifluoroacetic acid to fluoroaminosulfur pentafl~oridel~'(b. p. 25.3 "C (extr.), m. p.
-71 "C). From this, HF is eliminated by potassium fluoride,
and the title compound F-N=SF4 is obtained in 85% yield.
It is a colorless gas, stable to at least 100 "C (b. p. - 13.5 "C,
m. p. - 99 "C). The elemental composition has been secured
by vapor density determination ( M , exp. 142.7, calc. 141.02),
and by mass spectroscopy (70 eV, m / e = 141 ( M : ) and fragments). Structural information was obtained by vibrational
spectroscopy and 19F-NMR.The IR spectrum (NaCl region)
shows absorptions at 1128 (z&, 930 (vsF), 870 (vSF), 757
(vNF), and 648 (tis N) cm-I. The spectrum is very similar to
that of SOF4[51with an additional N-F stretching frequency. The N==S valence vibration occurs at about 100 cm-'
lower than expected, a surprising result in view of the rigidity
of the molecule. The highly complicated I9F-NMR spectrum
could still be simulated as a A2BCD spin system161.The spectrum shows the sulfur to have a trigonal bipyramidal environment, with one equivalent pair and one nonequivalent
pair of fluorine atoms. The N-F group certainly occupies
an equatorial position, and in analogy to GH2=SF4['I the N fluorine atom will be oriented in the axial plane.
This means that the molecule is rigid, with no change in
position of the N-fluoro atom being observed. The rigidity of
the F-N=SF4 molecule is in sharp contrast to the nonrigidity of the molecules CH3-N=SF4,
0=SF4[71,but is comparable to the behavior of CH2-==SF,[l1.
Only a Berry pseudorotation of the four S-fluorine atoms is
possible; however, it cannot be observed because of the remaining nonequivalency of the participating atoms.
It is still not explainable why F-N-SF,
does not form a
dimer with a (NS)2 four-membered ring unit, as is observed
in (CI-NSF&, which has not yet been observed as a monomer1'1.
is a weaker F- donor than SOF4[91.AsF5
forms an adduct at - 78 "C that is completely dissociated at
+ 20 "C. With SbF5, an explosion occur? at - 10 "C.Whether
the adduct contains cationic species NGSF, or FN=--:$F, remains to be seen.
Received: February 6, 1980 [ Z 534 IE]
German version: Angew. Chem. 92,659 (1980)
[I] G. Kleemann, K. Seppell, Angew. Chem. 90, 547 (1978); Angew. Chem. Int.
Ed. Engl. 17, 516 (1978); H. Bock, J. E. Boggs. G. Kleemann, D. Lenrr. H.
Oberhammer, E. U. Peters, K. Seppell. A . Simon, B. Solouki. ibid. 91. 1008
(1979) and 18.944 (1979), respectively.
[Z] R. Mews, Angew. Chem. 90,561 (1978); Angew. Chem. Int. Ed. Engl. 17,530
[3] A . F. Cli/ford. G. A . Zeilenga, Inorg. Chern. R, 979 (1969).
[4] D. D. DesMarfeau, to be published.
[5] K. 0. Christe, C. J. Schack, E. C. Curlis. Spectrochim. Acta 3 3 A . 323
[6] Computer simulation with the LACOON 3 program. We wish to thank Professor H . Friebolin and his co-workers at Heidelberg for supplying the program.
[7] The temperature dependence of the 'OF-NMR spectrum of CH3-N . SF, is
drastic, but has not yet been analyzed [2]. An AIBCXl spectrum is obtained
at -80°C E. L. Muelterties, W. Mahler, K. J. Packer, R.
for CF,-N=SF,
Schmurzler, Inorg. Chem. 3, 1298 (1964). Fluorine exchange in SOF, could
not be frozen until - 148 "C.
[8] R. Mews, 0.Glemser, 9th International Fluorine Symposium, Avignon
191 F. Seel, 0.Detlmer, 2. Anorg. Allg. Chem. 301. 113 (1959); M. Brownstein, P.
H . W. Dean, R. Gillespie, J. Chem. Soc.Chem. Commun. 1976. 9.
Fig. 1 . "F-NMR spectrum of F-N=SF4 (56.4 MHz, -80°C): experimental (above) and simulated (below) as AIBCD spin system
with SA= -52.7, & = -45.0, S,= -13.2, SU=43.9, JA,=213.9 Hz, JA,=194.0 Hz. JA,,=19.6 Hz, Jac= 10.7 Hz, Jsu= -92.7, and
JCD= 226.8 Hz.
The spectrum retains its character from - 80 to + 100 "C.
Only a broadening of the B, C, and mainly D signals is observed, probably due to quadrupole relaxation of the nitrogen atom.
Prof. Dr. D. D. DesMarteau [ 1
Department of Chemistry, Kansas State University
Manhattan, Kansas 66506 (USA)
Prof. Dr. K . Seppelt
Institut fur Anorganische und Analytische Chemie der Freien Universitat
Fabeckstrasse 34-36, D-1000 Berlin (Germany)
To whom correspondence should be addressed.
This work was supported by the Deutsche Forschungsgemeinschaft, the
Fonds der Chemischen Industrie, the U. S . Army Research Office, and by the
Alexander von Humboldt Stiftung (fellowship for 5.5.D.).
Angew. Chem. Inf. Ed. Engl. 19 (1980) No. 8
Structure of [(C0)5CrNEt2]BF4,
a Key Organometallic Compound;
Reaction to Give the Carbene Complex
By Ulrich Schubert, Ernst Otto Fischer, and Dieter
Our preparation of carbene complexes by reaction of
hexacarbonylchromium, -molybdenum, or -tungsten with
nucleophiles and alkylation of the resulting acylmetalates'21
[*I Prof. Dr. E. 0. Fischer, Dr. habil. U. Schubert, Dip1.-Chem. D. Wiltmann
Anorganisch-chemisches Institut der Technixhen Universitat Miinchen
Lichtenbergstrasse4, D-8046 Garching (Germany)
0 Verlag Chemie, GmbH. 6940 Weinheim, 1980
S 02.50/0
is not applicable to weak nucleophiles. In such cases, a route
proceding via the ~ e q u e n c e l ~ . ~ ]
[ (C O)5Cr=C-NEt2]BF4
group by an alkyl or aryl moiety increases the positive charge
on the metal atom by eliminating (B), thereby further weakening the Cr-Cco trans bond. The corresponding cationic
carbyne complexes are consequently destabilized to such an
extent that they can no longer be observed or isolated under
the usual conditions.
( C O)5Cr-C,
i. e. indirect exchange of an alkoxy group for another nucleophilic substituent (Nu), gives the desired product.
The general applicability of step (1)+(2) has now been
confirmed once again, i. e. by the successful synthesis of an
arsenic-substituted carbene-complex by reaction of (1) with
potassium diphenylarsenide (Nu = AsPh2).The spectroscopic
data of (C0)5CrC(AsPh2)NEt2are given in Table 1.
Table 1 . Spectroscopic data of the diphenylarseniocarbene complex (2),
IR ( vC0 region, n-pentane NaCl optics): 2055 (m). 1942 (vs), 1936 (vs) cm . '_
MS (C1 source, 30°C): m/e=449 [M-ZCO]+. 421 [ M - 3 C O ] + . 393
[M-4CO]+, 313 [arbenel+.
'H-NMR ([Dal-acetone, -30°C. rel. to CD,COCD2H). 6=7.39 (lOH, S CnH5),
4.62 and 3.97 (each 2 H, Q; CH2, E,Z isomers). 1.66 and 0.78 (each 3 H, T CH,,
"C-NMR ([D,]-acetone. - 2 0 ° C rel. to CD,COCD2H): 6 = 287.74 (CEarhcnc),
225.29 (CC0.,,an \), 218.0 (C,,,,,), 142.13, 133.85, 130.03 and 129.54 (C,,,,,,),
59.69 and 56.69 (CH2: E Z ) . 15.11 and 14.21 (CHx E.Z).
Fig. 1 . Crystal structure of ( I ) with selected impomnt distances (pm) and angles.
The standard deviations of the distances are 1 pm for Cr-C and 2 pm for C-0
and C-N.
Since the carbene complexes accessible by reaction of (1)
with nucleophiles are themselves of preparative and theoretical interest (cf. [4,51), the cationic carbyne complex (I) assumes a key role. Carbyne(pentacarbony1)metal cations
[(CO),MCR]@(M = Cr, Mo, W) have also been discussed as
intermediates in connection with the preparation of carbyne
from carbene complexes[61but so far only those with R = NR;
have been isolated. Thus, fundamental information about
the nature of this class of compounds was expected from the
X-ray structure analysis['' of (1).
The most striking features of the structure of (1) (cf. Fig. 1)
are the long Cr-Ccarbyne bond relative to other aminocarbyne complexes of chrornium['".*I and the large Cr-Cco distance of the CO group trans to the carbyne ligand. The
Cr-Ccarbynebond in (1) is the longest observed so far, being
178 pm. Comparison with those of about 168-170 pm in
trans-halo(tetracarbony1)aryl or -alkylcarbyne complexes demonstrates the extensive participation of the resonance formula (B).
(C O)5Crr C-NE
t 2 ++
(C O)5C r = C =NEtz
( CO)5Cr=C-NEtz
Consequently, the Ccarbyne-Ndistance of 128 pm also lies
in the double bond region. The influence of the resonance
formula (C) is manifested not only in the reactions of (1) but
also in the fact that, in spite of the greatest Cr-Ccarbynedistance in the series of aminocarbyne complexes, the C-N
distance in (1) corresponds roughly to the value of 126 pm
found for tran~-Ph~Sn(C0)~CrCNEt~
(Cr-Ccarbyne= 174
pm)[Rbl.The extreme Cr-Cco distance to the CO group located trans to the carbyne ligand finally indicates that the
chromium atom also accepts some of the positive charge (resonance formula (A)).
The delocalization of the positive charge therefore extends
over the entire Cr-C-N unit. Replacement of the amino
0 Verlag Chemre, GmbH, 6940 Weinhelm. 1980
All operations are performed under N2 with dried, 0,-free
A red solution of KAsPhz [prepared by adding HAsPh2['I
(3 g, 13 mmol) in THF (20 ml) to a suspension of KH (0.53 g,
13 mmol) in THF (10 ml) at - 30 "C and allowing the mixture to react at room temperature] is slowly added to a suspension of (1) (4.36 h, 12 mmol) in THF (50 ml) at -60°C.
The mixture turns dark brown and (1) dissolves on stirring
for 30 min. The solvent is stripped off at - 30 "C and the residue is extracted with CH2C12prior to filtration. The filtrate
is concentrated to 10 ml and purified by column chromatography on silica gel at -40 "C with pentane/CH2C12(10: 1) as
eluent. After removal of solvent (2), Nu = AsPh2, is recrystallized from ether/pentane (5:l); yield 0.7 g (12%) of ocher
crystals, m. p. 57 "C (dec.).
Received: March 3, 1980 [Z 537 IE]
German version: Angew. Chem. 92, 662 (1980)
[I] Transition Metal-Carbyne Complexes, Part 58.-Part 57: E. 0. Fischer. W.
Roll, Angew. Chem. 92, 206 (1980); Angew. Chem. Int. Ed. Engl. 19, 205
( 1980).
121 E. 0. Fischer. Pure Appl. Chem. 24, 407 (1970); 30. 353 (1972); Angew.
Chem. 86. 651 (1974).
[31 E. 0.Fischer, W. Kleine, F R. Kreissl. Angew. Chem. 88,646 (1976); Angew.
Chem. Int. Ed. Engl. 15, 616 (1976).
I41 E. 0. Fischer, R. B. A . Pardy. U. Schubert, J . Organomet. Chem. 181, 37
(1979); and references cited therein.
[51 a) E. 0. Fischer. H. Fischer, U. Schuberf, R. B. A. Pardy, Angew. Chem. 91,
929 (1979): Angew. Chem. Int. Ed. Engl. 18,872 (1979); b) H. Fischer, J. Organomet. Chem., in press.
[61 E. 0.Fischer, U. Schuberf, J Organomet. Chem. 100, 59 (1975); H. Fischer,
A. Morsch, W. Kleine, Angew. Chem. 90, 914 (1978); Angew. Chem. Int. Ed.
Engl. 17, 842 (1978).
[71 [CloH,6rN051BF4; -30°C. orthorhombic. Pca2, ( Z = 4 ) , a=1361(2),
b=863(1). c=1282(2) pm, V=1506x 10°pm3, pc.,,=1.60g/cm3. A=71.069
~ . strucpm (MaK.,.graphite monochromator, Syntex P2,), 2 " ~ 2 f I c 4 5808
ture factors (FoZ3.00(F)), R,=0.075, R2=0.081
[8] a) E. 0.Fischer, G. Hurrner. W. Kleine, A. Frank, Angew. Chem. 87, 781
(1975); Angew. Chem. Int. Ed. Engl. 14, 760 (1975); b) U. Schubert, Cryst.
Struct. Commun. 9, 383 (1980); c) U. Schuberr. D. Neugebauer. P. Hofmann,
H. Fischer. A . Morsch, W. Kleine. Chem. Ber., in press
191 F C Mann. M. J. Prangell. J. Chem. SOC.1965. 4123.
0570-0833/80/0808 0644
.%02 50/0
Angew. Chem. In1 Ed. Engl. 19 (1980) No. 8
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bf4, complex, reaction, compounds, carbene, asph, organometallic, structure, key, give, 5crc, 5crnet2, net2
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