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Ketenimine Complexes from Metal Isocyanides and Diazoalkanes.

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The fact that an alloy had been prepared as a result of the
co-reduction was finally proved by recording a Mossbauer
spectrum (source: 57Co/Pt, 27 T ) [ l o l of the sample before
heat treatment. The spectrum shows the characteristic six
resonance lines for metallic iron. The total splitting (i.e., the
distance between the outer lines) is 36 T, a value which has
been found for comparable alloys formed by melting but
which is 3 T larger than for pure iron.
Therefore the co-reduction of metal salts in organic solvents with hydroorganoborates provides a method of preparing single-phase, almost amorphous alloys of two or
more components (Table 3 ) .
The redox potential of sodium hydrotriethylborate in
T H F (supporting electrolyte: NBu,PF,) was determined
electrochemically to be -0.77 V, corresponding to -0.62 V
in H,O.["l Thus, the reaction between the metal salt and the
hydride proceeds either as a reduction or as a metathesis
depending on the particular metal involved. The findings
described above can be rationalized on the basis of the
HSAB concept."'] The metal ions M@act as soft acids and
compete with the moderately hard acid BR3[13]for the soft
basic hydride ion to form 1. If Me is a softer acid than BR,,
the hydride is transferred to M@, the resulting MH then
decomposes spontaneously to metal and hydrogen [Eq. (d)].
MX
- M'X
+ M'(BR,H)-(M...H...BR,]-[MH]
+ BR,
Experimental
Preparation of an iron/cohalt alloy from FeCl,, CoCl, and LiBEt,H in THF:
A solution of 9.1 g (56 mmol) of FeCI, and 3.1 g (24 mmol) of CoCI, in 2.5 L
o f T H F was added dropwise to a stirred 1.7 M (255 mmol) solution of LiBEt,H
in THF over 5 h at 23 "C. After stirring overnight, the iron/cobalt alloy was
separated from the clear reaction solution and washed twice with 200 mL portions of T H E The product was then stirred with 300 mL of ethanol and subsequently with a mixture of 200 mL of ethanol and 200 mL of T H F until the
evolution of gasceased. Finally, the product was washed again with 2 x 200 mL
of THF. The yield of alloy powder after drying in a high vacuum
mbar)
was 5.0 g (Table 3, No. 3); Particle size according to scanning electron microscopy: 10-100nm.
Received: October 25, 1989 [3607 IE]
German version: Angew. Chrm. 102 (1990) 324
Ketenimine Complexes from Metal Isocyanides
and Diazoalkanes **
By Beate Strecker and Helmut Werner *
Dedicated to Professor Giinther Wilke on the occasion of his
65th birthday
Carbene-metal complexes react with isocyanides under
mild conditions to give ketenimine-metal compounds which
are useful building blocks for the synthesis of four-, five-,
and six-membered carbo- and N-heterocycles."' With regard
to the converse reaction, namely addition of a free carbene
to a metal isocyanide, so far the only example has been
the synthesis of the nickel complex Ni[q'-N,C(tBu)N = C = C(CN),](CNtBu), .['I
As part of a study of [2 + 21- and [2 + 31-cycloadditions of
cobalt isocyanide complexes [(C,H,)CO(CNR)(PM~,)],[~]
we have found that their reactions with carbene sources, as
for instance diaryldiazomethanes, opens up a facile entry to
ketenimine complexes. This formal [2 I]-cycloaddition of a
carbene to a M = C = NR moiety reinforces our recently developed method of adding a nitrene to an M = C = C H R
unit, which leads to an N,C-bound ketenimine 1igar1d.I~~
The cobalt compounds 1 and 2 react with Ph,CN,,
(p-Tol),CN,, and 9-diazofluorene in acetone at -78 to
20 "C to give the dark-colored, slightly air- and moisture-sensitive complexes 3-6.f5]
The "side-on'' coordination (xbond) of the ketenimine ligand which is expected for electron-rich ligand-metal fragments['] is clearly demonstrated
by the IR and NMR spectroscopic data.[@Moreover, these
data confirm that in 3 and 4 the ketenimine is coordinated
via the C = C bond, whereas in complexes 5 and 6 it is bound
via the C = N bond. Supporting evidence for the two types of
bonding is provided by: 1) the difference in the NCC stretching frequencies in the IR (ca. 1695cm-' for 3 and 4 in
contrast to ca. 1625 cm- for 5 and 6);2) the different chemical shift and coupling constants of the signal of the NCH,
protons in the 'H-NMR spectra; and 3) the considerable
difference in the chemical shift of the signals of the C, and C,
atoms in the I3C-NMR spectra of 3,4 and 5, 6.[@
+
[(C,H,)Co(CNR)(PMe,)]
+
R2CN,
+
-N,
[(C,H,)Co(RN=C=CR,)(PMe,)]
1,R=Me
a) R. Kieffer, F. Benesovsky, Ullmanns Encykl. Techn. Chem. 4th Edit.
Vol. 19, pp. 563: b) K. H. Roll, Kirk-Othmer, Encyrl. Chem. Technol.. 3rd
Edit. Vol. 19, pp. 28.
R. Krabetz. W. D. Mross, UllmannsEncykl. Techn. Chem. 4th Edit. Vol. 13,
pp. 517.
S. C. Davis, K. J. Klabunde, Chem. Rev. 82 (1982) 152-208.
N . Ibl, Chem Ing.-Tech. 36 (1964) 601-609.
R. D. Rieke. Organometallics 2 (1983) 377.
H. Bonnemann, B. Bogdanovic, DOS 3541 633 (May 27, 1989), Studiengesellschaft Kohle mbH.
R. Koster, Methoden Org. Chem. (Houben-Weyl), 4th Edit. Vol. XII/3b,
pp. 798.
We thank Dr. G . Block and E. Schauf, Gesellschaft fur Systemtechnik
mbH, Munchener Strasse 100, D-4300 Essen 1 (FRG), for the measurement and interpretation of the X-ray diffractograms and for the scanning
electron microscope studies.
E. A. Moelwyn-Hughes: Physikalische Chrmie, Thieme, Stuttgart 1970,
pp. 325.
We acknowledge the help of Prof. Dr. Cf.: Keune and DipLIng. U . von
Hiirsren, Laboratorium fur Angewandte Physik. Universitit-Gesamthochschule Duishurg, for recording and interpreting the Mosshauer
spectra.
We thank Prof. Dr. U . Kolle, Institut fur Anorganische und Elektrochemie,
Technische Hochschule Aachen, for providing us with these results.
HSAB (Hard and Soft Acids and Bases): R. G . Pearson, Surv. Prog. Chem.
5 (1969) pp. 1-52,
L. Kold~tz(Ed): Anorganikum, Teil 1, VEB Deutscher Verlag der Wissenschaften. Berlin 1981, pp. 474.
Angen. Chem. Inr. Ed. Engl. 29 (1990) No. 3
2, R = (S)-CHMePh
R
R
5, 6
3, 4
3, R = Me, C R 2 = CPh,
4, R = Me, C R 2 = C(p-Tol),
5, R = Me, CR; = C(C,,H,)
6, R = CHMePh, C R 2 = C(C,,H,)
[*I Prof. H. Werner, Dipl. Chem. B. Strecker
Institut fur Anorganische Chemie der Universitit
Am Hubland, 8700 Wurzhurg (FRG)
[**I This work was supported by the Volkswagen Foundation and the Fonds
der Chemischen Industrie. We thank Prof. P. L. Pauson. University of
Strathclyde. Glasgow for helpful discussions and P. Schwab for experimental assistance.
Q VCH Verlagsgeseilschaft mbH. 0-6940 Weinheim, 1990
0570-0833/90jO303-0275 $02.50/0
27 5
The proposed structure of 3 and 4 is further supported by
a comparison of the 13C-NMR data with those of the rhodium complexes [(C,H,)Rh(q'-C,C-RN=C=CHPh)(PiPr,)]
(R = p-SO,C,H,Me, O-C,H,NO,)[~~Iand [(C,H,)Rh(q2CH, = C = CHR)(PiPr,)] (R = H, Me, Ph),[71in which the
respective heteroallene and allene ligands are also coordinated via a C = C bond. The reaction of 2 with 9-diazofluorene affords, as expected, two diastereomers, which can be
easily discerned by the duplicate sets of signals in both the
'H- and "C-NMR spectra of 6.I6]
By adding an equimolar amount of iodine to toluene solutions of complexes 3-6, the corresponding ketenimines 710 are formed. C,H,Co(PMe,)I, is obtained as by-product.[81Compounds 7 - 10 are soluble in most organic solvents
and can be isolated in good yields as yellow, partially oily
materials. Compound 7 had previously been described and
was spectroscopically characterized;['] 8- 10 are, to our
knowledge, new compounds not yet reported in the literature. In the IR spectra, very intense bands are found at ca.
2020 to 2030 cm-', which are characteristic for ketenirnines;["] this is also the range expected for IR bands typical
of cumuIenes.[' '1
R/CR; see 3--6 (above)
Since both cobalt complexes of the type [(C,H,)Co(L)(CNR)] 'I as well as diaryldiazoalkanes are easily accessible, we assume that other novel ketenimines, similar to 8-10,
can also be prepared in two steps in this way. It is predicted
that isocyanide complexes, like carbene complexes,[" 31 will
establish themselves as useful building blocks for the synthesis of various heterocyclic compounds.
'
Received: August 28, 1989 [Z 3523 IE]
German version: Angen. Chem. 102 (1990) 310
Publication delayed at authors' request
[l] R. Aumann, Angew. Chem. 100 (1988) 1512; Angew. Chem. lnt. Ed. Engl.
27 (1988) 1456, and references cited therein
[2] D. J. Yarrow, J. A. Ibers, Y. Tatsuno, S . Otsuka, J Am. Chem. Sac. 95
(1973) 8590.
[3] a) H. Werner, B. Heiser, C. Burschka, Chem. Ber. 115 (1982) 3069; b) H.
Werner, B. Heiser, H. Otto, ihrd. 1f8 (1985) 3932; c) review: H. Werner in
A. de Meijere, H. tom Dieck (Eds.)- Orgonometallics in Organrc Synrhesk,
Springer, Heidelberg 1987. p. 51.
a) A. Hohn. H. Werner, Chem Ber. 121 (1988) 881; b) U. Brekau. Dis.$erration. Universitlt Wurzburg 1989.
a) Experimental procedure for 3. A solution of Ph,CN, (1.0 mmol) in
acetone (5 mL) was added at -78 'C to a solution of 1 (I.Ommo1) in
acetone (15 mL). The reaction mixture was stirred and allowed to warm to
room temperature (3.5 h). The solvent was then removed in vacuo and the
residue extracted with 20 mL of ether. On cooling the extract to -78 'C,
red needles were formed; yield 63%; m.p. 135':C(dec.); b)4: recrystallization from benzenelpentane (1 : l ) ; red-brown crystals, yield 54%; m.p.
13O.K (dec.); c) 5: work-up directly after warming to room temperature;
recrystallization from benzene/pentane (1 : 1); dark green crystals; yield
68%. m.p. 45 'C (decomp.); d) 6: work-up directly after warming to room
temperature; dark green crystals from ether at -78 'C; yield 63%; m.p.
47 ' C (dec.). Satisfactory elemental analyses (C,H,N) were obtained for all
compounds
Spectroscopic data. 3: M , = 407 (MS); IR(KBr): v(NCC) = 1700cm-';
'H NMR (90 MHz, C,D,): 6 = 7.36 (m, C,H,), 4 25 (d, Jp,, = 0.9 Hz,
C,H,), 3.97 (d. JPH= 0.9 Hz, NCH,), 0.32 (d, JPH= 8.9 Hz, PMe,);
13C NMR (22.5 MHz, CeD,): b = 207.1 (d, J,, = 18.6 Hz, = C = ) , 152.4,
1465,128.2,127.1,125.3,122.9(alls,C,H,).84.9(d,J,= 1.7Hz,C5H,),
46.2 (d, Jpu= 2 6 Hz. NCH,), 19.4 (d, Jpc = 28.2 Hz, PMe,), 11.0 (d.
Jpc = 2.6 Hz. = C P h 2 ) . 4 : M, = 435 (MS); IR (KBr): v(NCC) =
1690 cm-', ' H NMR (90 MHz, C,D,): b = 7.55 (d, J,,, = 8.0 Hz. C,H,),
6.94 (d, JHH = 8.0 Hz, C,H,), 4.31 (d, J,, = 0.8 Hz, C,H,). 4.00 (d,
276
CJ
VCH Veriag.sge~~,li.~chajr
mhH. D-6940 Weinhelm. 1990
= 0.6 Hz, NCH,), 2.05 ( s , C,H,CH,), 2.02 (s, C,H,CH,), 0.38 (d,
JPH= 8.9 Hz, PMe,); 13C NMR (50.3 MHz, C,D,): 6 = 207.9 (d,
Jpc = 17.8 Hz. = C = ) . 149.4. 143.7, 134.5, 131.8 (all s, C,H,), 84.9 (s,
CSH,), 46.2 (d, Jpc= 2.8 Hz, NCH,), 21.1 (s, C,H,CH,), 20.9 (s,
C,H,CH,), 19.0 (d, Jpc = 27.8 Hz, PMe,), 10.7 (s, br, =C@-tol),).-5:
M , = 405 (MS); IR(KBr): v(NCC) = 1625 cm-'; 'H NMR (90 MHz,
C,D,): 6 = 9.05 (d, br, JHH= 7.5 Hz, C,H,), 7.73 (m, C,H,), 4 54 (d,
JPH= 0.5 Hz. C,H,), 2.66 ( s , NCH,), 0.46 (d, JPH
= 10.2 Hz. PMe,);
I3C N M R (50.3 MHz, C,D6): 6 = 175.2 (d, Jpc= 18.7 Hz, = C = ) , 142.8,
137.9,136.8. 134.2.125 7,125.5,122.7. 122.3, 121.5, 120.4, 120.1, 118.9(all
S , CbH,), 101.9 (s. =C(C,,H,)), 83.8 (s, C,H,), 45.0 ( s , NCH,). 16.4 (d,
Jpc = 28.3 Hz, PMe,).-6:
IR(KBr): v(NCC) = 1626 cm-'; 'H NMR
(90 MHz, C,D,): 6 = 9.11 (d. br, JHH = 8.2 Hz, C,H,), 7.19 (m. br, C,H,
= 6.9 Hz,
and C,H,). 5.03 (4, JHH= 6.6 Hz. CHMePh), 4.80 (4. JHH
CHMePh), 4.39 (d, JPH= 0 6 Hr. C,H,), 4.27 (d. JPH= 0.5Hz, C,H,),
= 6.6 Hz. CH(CH,)Ph),
1.56 (d, Jut1 = 6.8 Hz, CH(CH,)Ph), 1.01 (d, JHH
0.44 (d. J,,= 10.1 Hz. PMe,), 0.43 (d, JPH= 10.2 Hz, PMe,); 13CNMR
(50.3 MHz, C,D,): 6 = 162.9 (d, Jpc = 18.9 Hz, = C = ) , 160.4 (d.
Jpc = 17.5 Hz, = C = ) , 145.8, 144.6, 143.1, 142.6, 138.5, 138.0, 135.7,
135.5. 134.0. 133.7. 128.3, 127.8. 127 7, 127.1, 126.8, 126.6, 125.5. 125 3.
125.2,121.7, 121 5,121.1,120.5, 120.2. 116.6,116.5(alls,C6H,andC,H,),
97 7 ( S , =C(C,,H,)), 96.7 (s, = C(C,,H,)), 82.8 (s, C,H,), 82.7 (s, C,H,),
58.1 (s. CHMePh), 56.2 (s, CHMePh), 21.7 (s, CH(CH,)Ph), 17 7 (s,
CH(CH,)Ph), 16.4 (d. Jpc = 27.8 Hz, PMe,), 16.2 (d, Jpc = 27.9 Hz,
PMe,).
[7] J. Wolf, R.Zolk. U.Schubert, H. Werner, J Organomet. Chem. 340 (1988)
161.
[XI H. Werner, B. Juthani, Z. Anorg. ANg Chem. 473 (1981) 107.
[9] a) C. L. Stevens, J. C. French, J. Am. Chem. Sac. 76 (1954) 4398; b) S.
Otsuka, A. Nakamura, T Yoshida, J Organomet. Chem. 7 (1967) 339.
[lo] Spectroscopic data. 8: IR (C,H,). v ( N = C = C ) = 2018cm-'.-9:
IR
(C,H,):
v ( N = C = C ) = 2030cm-'; 'H NMR (200 MHz, C,D,):
d = 7.48 (m, C,H,), 2.74 (s, NCH,): ''C NMR (50.3 MHz, C,D,).
b = 176.0(s, = C = ) , 138.8, 135.8, 126.5. 125.2, 121.7, 120.8 (all s, C,H,),
37.6 (s, NCH,).-10.
IR (C,H,):
71.3 ( s . =C(C,,H,)),
v ( N = C = C ) = 2020cm-'; 'H NMR (90 MHz, C,D,): b = 7.31 (m,
C,H,), 4.62 (4. JH,,= 6.6 Hz, CHMePh), 1.36 (d, J,[,, = 6.6 Hz,
CH(CH3)Ph); I3C NMR (22.5 MHz, C6D,): b = 177.2 (s, = C = ) , 142.1,
138.7, 135.9, 129.0, 127.7, 126.6, 126.4, 125.3, 121.6, 120.8 (all s, C,H,),
73.1 (s, =C(C,,H,)), 63.6 (s, CHMePh), 24.4 (s, CH(CH,)Ph).
G. R. Krow, Angen.. Chem. 83 (1971) 455; Angew. Chem. Int. Ed. Engl 10
(1971) 435.
a) H. Werner, S. Lotz, B. Heiser, J Organomet. Chem. 209 (1981) 197; b)
B. Heiser. H. Werner, Synth. React. h o g . Met..Org. Chem 16 (1986) 527;
c) B Strecker, Diplomarheit Universitat Wiirzburg 1987.
K. H. Dotz, Angen. Chem. 96 (1984) 573; Angew. Chem. Int. Ed. En,g1. 23
(1984) 587.
JPH
Cycloaddition Reactions of CpCo-Stabilized
Cyclobutadiene Derivatives **
By Rolf' Gleiter * and Detlef Kratz
Dedicated to Professor Paul von Rague Schleyer on the occasion of his 60th birthday
The reaction of alkynes to form arenes using homogenous
transition metal catalysts is described in the literature in
terms of catalytic loops as depicted in scheme
The
formation of cobalt-stabilized cyclobutadiene derivatives B
is usually considered as an unwanted side reaction and as a
pathway constituting a dead end of [2 + 2 + 21-cyclotrimerization reactions to arenes D with catalysts of the type
CpCoL, .
These complexes B withdraw the catalytically active species, the CpCo-fragment, from the trimerization cycle and
I'[
[**I
Prof. Dr R. Gleiter, Dipl. Chem. D. Kratz
Organisch-chemisches Institut der Universitat
Im Neuenheimer Feld 270, D-6900 Heidelberg (FRG)
This work was supported by the Deutsche Forschungsgemeinschaft
(SFB 2471, the Volkswagenwerk-Stiftung,the Fonds der Chemischen Industrie, and BASF Aktiengesellschaft. D.K. thanks the Studienstiftung des
Deutschen Volkes for a postgraduate grant.
0570-0833~90j0303-027fi
$02.50/0
Angeir. Chem. hi.Ed. Engi 29 (1990) No. 3
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