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Synthesis and Reactions of 5-Cyclopentadienylbis(ethene)cobalt.

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Table I. ’H-NMR spectra (360 MHz) of the complex 1-pyrene in D 2 0
([1]=5.5 x IO-’M, [I-pyrene]=2.9 x ~ O - ’ M ; 6 relative to sodium 2,2,3,3-tetradeuterio-3-(trimethylsilyl)propionate(TSP) in D 2 0 as ext. standard) and,
for comparison, of pyrene (6 relative to TSP,,, in [D&nethanol) and 1
([I]= 2 x 10-4-7 x lo-’ M, 6 relative to TSP,,, in D,O]). J in Hz.
H- 1
H-2
H-4
Pyrene in [DJMethanol
Complex 1-Pyrene in D20
303 K
8.21 (d, J=7.6, 4 H )
8.02 (t, J=7.6, 2H)
8.10 (s, 4 H )
7.19 (d, J=7.5, 4 H ) 7.19
7.58 (t, 5=7.5, 2 H ) 7.54
6.95 (s, 4H)
6.95
303 K
353 K
1 in D20
303 K
1.87 (m, 8 H )
1.96 (“t”,
J=7,8H)
Aryl-CH, 2.08 (s, 24H)
H-3”
2.73 (m, 8H)
N(I?-CH3 3.16 (s, 2 4 ~ )
N( 1“)-CH,
H-2‘
3.43 (m, 16H)
H-2”
H-3’
H-3
3.88 (“t”.
J=7,8H)
7.01 (s, 8 H )
H-2
H-10
353 K
1.87
I .96
2.08
2.68
3.15
3.41
1.13 (m, br, 8 H )
1.47 (m. br, 8 H )
2.10 (s, 24H)
la1
2.96 (S, 12H)
3.18 (s, 12H)
3.50 (m, 8 H)
3.88
[a]
6.95
7.30 (s, br, 8 H )
1.17 (m, 8 H )
1.45 (“t”,
J=7.5, 8 H )
2.09 (s, 24H)
2.86 (m, 8H)
2.96 (s, 12H)
3.17 (s, 12H)
2.94 (m, 8 H)
3.48 (“t”,
J=5.2, 8 H )
3.10 (“t”,
5=7.5, 8 H)
7.23 (s, 8 H )
[a] These signals are very broad and collapse at 6=2.6-3.1
2
2,6-dimethylphenol, 576-26-1 ; ethyl cyanoacetate, 105-56-6; piperidine-4,4diacetic acid, 86748- 14-3; pyrene, 129-00-0; y-cyclodextrin, 17465-86-0.
121 F. Diederich, K. Dick, Tefruhedron Lett. 23 (1982) 3167.
[3] Correct analytical results and appropriate spectra were obtained for
these compounds.
[lo] A 8 x IO-’M (0.162 mg/L) aqueous solution of pyrene can be prepared
at room temperature using the method described; this value, obtained
photometrically, is completely consistent with the literature data: H. B.
Klevens, J. Phys. Chem. 54 (1950) 283; W. W. Davis, M. E. Krahl, G. H.
A. Clowes, J. Am. Chem. SOC.64 (1942) 108.
1161 The ’H-NMR experiment was performed using a similar concentration
ratio [l]:[pyrene] and a concentration of complex of 5 . 5 ~IO-’M (303
K); here, almost identical chemical shifts (e.g. of the pyrene protons at
6=7.57, 7.19, and 6.95) and similar line widths for the signals of 1 are
obtained-an important piece of evidence for the same complex form at
concentrations below the CMC of 1.
Synthesis and Reactions of
q5-Cyclopentadienylbis(ethene)cobalt
By Klaus Jonas*, Etienne Deffense, and
Dietrich Habermann
Metallocenes react with alkali metals and olefins, with
elimination of alkali-metal cyclopentadienides, to give
transition metal-olefin or alkali metal-transition metal-olefin complexes[31.Thus, reaction of cobaltocene (Cp2Co)
with potassium and ethene in diethyl ether leads to formation of the bis(ethene) complex l .
CP2Co + K + 2C2H4
Et20
-20toOCC
’ CpCo(C2HS2 f
KCp
1
[email protected];
9
This unusually facile entry to 1 (one-step synthesis, yield
85%), whose ethene ligands are readily replaceable, makes
1 a very useful starting material in organometallic chemistry (cJ Supplement). Of particular interest are the reactions
of 1 with alkynes or nitriles since, with C ~ C O ( C Oor
)~
CpCo(C,H,,) at temperatures > lOO”C, cobalt-catalyzed
alkyne cycl~trimerization[~~~
or cocyclization of alkynes
and nitriles to afford pyridine derivatives occurs1261.
At - 10 “C, 1 reacts with 2-butyne in n-hexane to afford
a new deep-red complex, which can be recrystallized from
boiling n-hexane, and which, according to the elemental
analysis and mass spectrum, has the composition 9.
7
Pyrene
12
rings which, favored by additional hydrophobic interactions, can approach the pyrene. In contrast to the highly
resolved pyrene signals between 273 and 353 K, the signals
of 1 in the complex are very broad below 333 K. This
probably arises from the exchange of pyrene on the ‘HNMR time scale with the host molecules present in excess[16!
By analogy, inclusion complexes were prepared from 1
and water-insoluble aromatic hydrocarbons such as perylene, fluoranthene, naphthalene, and durene. ’H-NMR
and optical spectra confirm the results obtained from the
complexation of pyrene.
Received: April 28, 1983 [Z 363 IE]
German version: Angew. Chem. 95 (1983) 730
The complete manuscript of this communication appears in:
Angew. Chem. Suppl. 1983, 730
CAS Registry numbers:
1, 86765-98-2; 2, 32161-06-1; 3, 86748-13-2; 4, 86748-15-4; 5, 86748-16-5;
4 86748-17-6; 7,86748-18-7: 8, 86748-12-1; 9, 86748-19-8; 10, 86748-20-1;
11, 86748-21-2: 11. 4FS03CH,, 86765-97-1 ; 12, 86748-22-3; 13, 86748-23-4;
716
0 Verlag Chemie GmbH, 4940 Weinheim, 1983
The product 9 (yield 46%) was investigated crystallographically but, because of disorder in the crystal lattice, an
accurate description of the molecular geometry could not
be obtained. However, these results indicate that the cobalt
atom in 9 is sandwiched between a cyclopentadienyl ring
and a hexamethylbenzene ring”’]. The magnetic moment,
peff=2.85 pB,of solid 9 is almost exactly that expected for
two unpaired electrons according to the spin-only formula.
We assume, therefore, that 9 exists as qs-CSHsCo-q6C6(CH&, which is isoelectronic with the cation of
[(C6(CH3)6)2Co]PF,[Z71,
and in which the krypton electronic
configuration is exceeded by two electrons. This probably
accounts for the ease of displacement of the hexamethylbenzene ligand, e.g., with CO, and why 9 is the first reported (CsHs)Co-compound that can catalyze the cyclotrimerization of alkynes and cocyclization of alkynes and nitriles at room temperature.
[*] Priv.-Doz. K. Jonas, Dr. E. Deffense, Dr. D. Habermann
Max-Planck-Institut fur Kohlenforschung
Postfach 01 1325, D-4330 Miilheim an der Ruhr 1 (Germany)
0570-0833/83/0909-0716
S 02.50/0
Angew. Chem. Int. Ed. Engl. 22 (1983) No. 9
Received: April 25, 1983 [Z 353 IE]
German version: Angew. Chem. 95 (1983) 729
The complete version of this communication appears in:
Angew. Chem. S ~ p p l 1983.
.
1005-1016
[3] K. Jonas, C. Kriiger, Angew. Chem. 92 (1980) 513; Angew. Chem. Int. Ed.
Engl. I 9 (1980) 520.
[IS] C. Kriiger el al., unpublished results.
I251 K. P. C. Vollhardt, Acc. Chem. Res. 10 (1977) 1.
[261 H. Bonnemann, Angew. Chem. 90 (1978) 517; Angew. Chem. Int. Ed.
EngL 17 (1978) 505.
[271 E. 0. Fischer, H. H. Lindner, J. Organomet. Chem. I(1964) 307; M. R.
Thompson, C. S. Day, V. W. Day, R. I. Mink, E. L. Muetterties, J. Am.
Chem. SOC.102 (1980) 2979.
63%, b. p. = 150 "C/O.Ol torr, m. p. = 30-32 "C]. The diaminodihydropyrazines 5 are formed from 2a on reaction
with secondary amines [5d : 78%, m. p. = 143- 144 "C (decamp.); 5 e : 52%, decomp. above 126°C; 5 f : 48%,
m. p. = 165.5 "C (decomp.)]. In the presence of anthranilic
acid as the amine component the sparingly soluble 7,15dihydropyrazino[2,1-b:5,4-b~-diquinazoline-5,13-dione
3
[54%, ocher-colored platelets, m. p. = 298 "C] is obtained
from 2a, b. The structure type 3 also occurs in the piperazine derivative 4 (m.p. >3OO"C), which forms almost
quantitatively from 2a and malononitrile. The desired diazaquinodimethanes 6 , which correspond to the bis(ethylenedithio)-p-q~inodimethanes~~~,
are formed by reaction
of 2 with 2-methylthio-l,3-dithiolanyliummethyl sulfate
[6a: 43%, yellow needles, rn.p.=218-219"C; 6b: 21%,
orange needles, m. p. =285 "C (decamp.)].-Addition of tetrafluoroboric acid-ether to 6a yields the bis(tetrafluoroborate) of 6a as a brick-red powder.
Diazaquinodimethanes, Donor-Substituted Pyrazines,
and Dihydropyrazines**
By Rudolf Gornpper* and Walter Breitschaft
Dedicated to Professor Harald Jensen on the occasion
of his 60th birthday
Previously, the influence of ring N-atoms on the properties of quinodimethanes has only been studied with azaquinodimethanes""]. With one exceptiod2"], diazaquinodimethanes have not yet been described. Since diethoxydihydropyrazines can be converted into carbanions[2b1,it might
be expected that compounds of this type and aryl- and pyridylmalononitriles['] would react with cyclic carbenium
salts to afford diazoquinodimethanes.
The syntheses start from the dihydropyrazines 2 [by analogy to the formation of 2a from la'31,2b,c can be prepared from l b ; 2b: yield 77%, m.p.=103-104"C;
2c:
1a:X
=
0
3
7
0
1
NC
4
5
d:Rz= (CHZ)~
e : R P = (CH2)5
f : R2= (CH2)20(CHz)z
a : 1) R,O"BFF, CH2C12,A, 3d, 2) Na2HP0,/NaH,P0,, H 2 0 ; b: 1502OO0C, 1 h; c: 120"C, 1 h; d : CHCll, toluene or xylene, A, 15-60 h.
[*] Prof. Dr. R. Gompper, W. Breitschaft,
I**]
Institut fur Organische Chemie der Universitat
Karlstrasse 23, D-8000 Munchen 2 (Germany)
This work was supported by the Deutsche Forschungsgemeinschaft and
the Fonds der Chemische Industrie.
Angew. Chem. Inl. Ed. Engl. 22 (1983) No. 9
6
2
MeS
10
Sb,d,e,f
9
a : AcOH-pyridine, A, 30 min; b: 1) ZnBuLi, THF, -78 "C, 2) CS2, 3) Mel,
c: chloranil, toluene, A, 3 h; d : 1) nBuLi, THF, -78 "C, 2)
-78-25°C;
PhCHO, 3) AcOH, -78-25 "C, 4) 15O0C/O.01 bar or benzene, TosOH, A;
e : 130"C, 1 h.
3-Dimethylaminomethyl-2,5-bis(methylthio)pyrazine 10
I42%, yellow oil, b.p.= 170/0.01 torr] is formed upon heating 2b with N,N-dimethylformamide diethyl acetal in dimethylformamide. Apparently, the CH-acidity of 10 is insufficient to cause further reaction to a quinodimethane
such as 6 . Also the action of carbon disulfide on the Li salt
of 2b results only in formation of a monoadduct. Methylation of the latter affords 3-[bis(methylthio)methyl]-2,5bis(methy1thio)pyrazine 7 [39%, m. p. = 77-78 "C]. Reaction of the Li salt of 2b with benzaldehyde proceeds similarly. The 1 :1-adduct (not isolated, ~ f . ' ~ formed
l)
after hydrolysis can be converted into 3-benzyl-2,5-bis(methylthio)pyrazine 9 (44%, m. p. = 56.5-58.5 "C).
The new compounds 7, 9, and 10 are to be considered
as electron-rich pyrazines. Further compounds of the general type 8 can be prepared, by analogy to the oxidation of
2aE3],by heating 2b and 5d-f with chloranil in toluene
I8b: 42%, pale yellow needles, m.p.= 105-107 " C ; 8d:
52%, m.p.= 172.5-173 "C; 8e: l6%, m.p.=123123.5 " C ; 8f: 70%, m.p. = 182-182.5 "C].
The electron acceptor properties of 6 should be increased by twofold quaternization. 6, however, does not
react with alkylating agents. We, therefore, prepared the
ketene thioacetal 12 [59%, orange rhomohedra,
0 Verlag Chemie GmbH. 6940 Weinheim, 1983
0570-0833/83/0909-0717 $02.50/0
717
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