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Nickel(0)-Carbene Complexes.

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tion), Enraf-Noniius four-circle diffractometer, 0/2/1 scans, 20 "C. Mo,.
radiation (i
= 0.7169 A, graphite monochromator). 3336 independent reflections (fh + k +l), of which 2082 were observed [I>2u(1), R , =
0.0301, sinO/%,,, = 0.6 for solution and refinement. The structure was
determined by the heavy atom method using the XTAL2.6 program package. Positions of hydrogen atoms calculated, 173 parameters refined,
R = 0.053 (R, = 0.048), residual electron density 0.7 e k 3An
. enantiopole parameter'".'
refined to 0.004 confirms the absolute configuration
shown in Figure 2. Further details of the crystal structure may be obtained
from the Fachinformationszentrum Karlsruhe. Gesellschaft fur wissenschaftlich-technische Information mbH, W-7514 Eggenstein-Leopoldshafen 2, on quoting the depository number CSD-55614, the names of
the authors, and the journal citation.
[lo] S. R. Hall, J. M. Stewart (Eds.): XTAL2.6 User's Manual, Universities of
Western Australia and Maryland 1989.
[ l l ] H. D. Flack, Acta Cryslallogr. Sect. A39 (1983) 876.
[12] G . Bernardinelli, H. D. Flack, Acra Crystallogr. Secr. A4f (1985) 500.
1131 a) D. Enders in J. D. Morrison (Eds.): Asymmerric Synthesis Vol. 3, Academic, Orlando 1984, p. 275; b) D. Enders, Chem. Scrfpta 25 (1985) 139;
c) D. Enders, G. Bachstadter, K. A. M. Kremer, M. Marsch, K. Harms,
G. Boche, Angew. Chem. 100 (1988) 1580; Angew. Chem. I n l . Ed. Engl. 27
(1988) 1522.
[14] All new compounds gave correct elemental analyses and spectra (NMR,
IR, MS).
1151 D. Enders, H. Scherer, unpublished results; H . J. Scherer, Dissertarion,
Technische Hochschule Aachen 1991.
C6HSLi
C2H4
iBuNC
PMDTA
TMEDA
12
I1
butyl isocyanide, should likewise coordinate as masked acyl
carbanions to nickel(0) complexes.[718 reacts with [Ni(C,H,),]
in this sense in the presence of one equivalent of PMDTA
with formation of 11 (yellow crystals).1s1With TMEDA, 12
is obtained.
Nickel(o)-Carbene Complexes
By Barbara Gabor, Carl Kruger, Bernd Marczinke,
Richard Mynott, and Gunther WiEke*
Dedicated to Professor Horst Prinzbach
on the occasion of his 60th birthday
Isocyanides can be metalated, e.g. with n-butyllithium, in
the cr-position.['l We were interested whether [Ni(CNCH,),] 1
reacts with nBuLi in the same way to give [Ni(CNCH,Li),]
2. Compound 1, which is insoluble in pentane, dissolves when
treated in this solvent at -20 "C with four equivalents of
nBuLi. No liberation of n-butane is observed, either immediately or upon subsequent hydrolysis. Apparently, nBuLi
adds to the C=N bond, possibly with formation of [Ni{=C(C,H,)NLi(CH,)),] 3, which, however, could hitherto not be
isolated, since it undergoes secondary reactions.
Attempts to obtain 2 from LiCH,NC and [Ni(cod),] led to
displacement of 1,s-cyclooctadiene (cod) and loss of methylene to give Li,[Ni(CN),] 4,1z1which reacts with (CH,),SiCI
to the homoleptic complex of trimethylsilyl isocyanide
[Ni{CNSi(CH,),},] 5.[,] In a completely analogous way
[(tpp),NiCN][Li(thf),] 6 (tpp = triphenylphosphane) reacts
with (CH,),SiCl to give [(tpp),Ni{CNSi(CH,),}] 7.A compound analogous to 6 is formed from [Ni(cdt)] (cdt =
all-trans-I ,5,9-cyclododecatriene) and the addition products
8 of phenylltihium and tert-butyl isocyanide. Aside from
benzene and isobutene, formation of an adduct of LiCN and
[Ni(cdt)] is observed, in the presence of N,N,N'N-tetramethylethylenediamine (TMEDA) [ (cdt)NiCN][Li(tmeda),]
9 and of pentamethyldiethylenetriamine (PMDTA) [(cdt)NiCN][Li(pmdta)] 10. According to the NMR spectra all
three C=C bonds ofcdt are coordinated to the Ni atom. 9 and
10 can also be prepared directly from [Ni(cdt)] and LiCN.[41
[Ni(C,H,),] forms well-defined complexes with organolithium[51and organomagnesium compounds.[61Metalated
aldimines, such as the adduct 8 of phenyllithium and terr[*] Prof. Dr. G. Wilke, B. Gabor, Prof. Dr. C. Kriiger. Dr. B. Marczinke,
Dr. R. Mynott
Max-Planck-lnstitut fur Kohlenforschung
Kaiser-Wilhelm-Platz 1 , W-4330 Miilheim a. d. Ruhr (FRG)
1666
0 VCH
Verlagsgesellschaft mbH, W-6940 Weinheim, 1991
+ Hacac
+ CH,I
1
I
[2.1.1] Cryptand
- 30 OC. 68%
C,H,
I
14
13
I
-40°C,62%
O2
- CO - N,
X
I
X
C6H, - CO - N,
H
CH3
15
O2
16
Whereas lithiumacetyl- and lithiumcarbamoylnickel(o)
complexes cannot be converted into neutral nickel(0)-carbene
complexes,[g1the alkylation of 11 with CHJ in the presence
of [2.1 .l]cryptand successfully leads to formation of the neutral 16e nickel(o)-carbene complex 13.['01Without cryptand,
only amorphous products are obtained. The protonation of
11 with acetylacetone (Hacac) in ether leads in a comparable
way to 14.["] 13 and 14 precipitate in the form of orange-
0570-0833191j1212-1666$3.50+.25/0
Angew. Chem. Int. Ed. Engl. 30 (1991) N o . 12
yellow crystals, which are readily soluble in ether and THF,
but only sparingly soluble in pentane. 13 and 14 are the first
16e nickel(0)-carbene complexes; moreover, they contain
only olefins as further ligands.
For chemical characterization, 13 and 14 were converted
with oxygen into the acid amides 15 and 16, respectively. 13
and 14 are stable up to about room temperature and could
be characterized on the basis of NMR spectra. The 400-MHz
'H NMR and 75.5-MHz I3C NMR spectra of solutions of
131101
in [DJTHF are temperature dependent. At -30 "C a
sharp signal is observed at 6 = 48.6 for the ethene C atoms
and an AA'BB multiplet (6, = 2.38,6, = 2.18) for the diasterotopic geminal ethene protons. The signal for the carbeneCatom. with 6 = 280.4, lies in the range characteristic for
aminocarbene
At - 110 "C the rotation of the
ethene ligand about the bond axis to the Ni atom is frozen,
i.e. the ethene-C atom now affords two sharp signals at 6 =
50.4 and 46.0.
An unequivocal proof of the structure was provided by a
crystal structure analysis of 13 at - 173 0C.['31
It can be seen from Figure 1 that the ligands are arranged
around the nickel atom in a trigonal planar fashion. Two
with formation of the monophosphane complexes 17-19 in
good yieids in the form of red crystals as well as of the bisphosphane complex 20. Both in the case of 14 and 13, reaction with CO leads to the tricarbonylnickel carbene complexes 21 and 22, respectively, which are not accessible from
[Ni(CO)J and organolithium compounds.
CZl
y"'
n
Fig. 2. Crystal structure of 23. Selected bond lengths [A] and angles ["I: Ni-PI
2.165(1), NbP2 2.188(1), Ni-N 1.915(3),Ni-Cl 1.959(4), N-C1 1.375(5),Cl-NiN 41.6(2), Cl-Ni-P2 157.3(1), CI-Ni-P1 110.8(1), N-Ni-P2 116.7(1). N-Ni-P1
152.3(1), P2-Ni-P1 91.0(1) 115, 161.
Surprisingly, displacement of the ethene ligands from 14
takes a completely different course when chelate phosphanes
R2PCH2CH,PR2are employed. Between - 20 "C and room
temperature the complexes 23 and 24 are obtained in which
imines are coordinated to nickel(o), i.e. a rearrangement
takes place en route from 14 to 23 and 24.[l4]The structures
follow unequivocally from the NMR spectra and a crystal
structure analysis of 23 (Fig. 2).1151 Reaction of 14 with half an
equivalent of Ph,PCH,CH2PPh2 affords a red, finely crystalline precipitate, whose composition and spectroscopic
data are consistent with the presence of 25.
kgh2
Ph4
P h3
Fig. 1. Structure of 13 in the crystal. Selected bond lengths [A] and angles ["I:
Ni-CI 2.008(1). Ni-C2 2.008(1), Ni-C3 2.000(1), Ni-C4 1.999(1), Ni-C5
1.889(1), C5-N 1.320(1), C5-Phl 1.503(1), C1-C2 1.392(2), C3-C4 1.398(2);
Phl-C5-N 115.3(1), Phl-C5-Ni 108.7(1), N-C5-Ni 136.1(1) [13, 161.
coordination sites are occupied by the ethene units, the third
by the planar aminocarbene ligand. The coordination plane
of the metal (Ni, midpoint of C1 -C2, midpoint of C3-C4)
forms a dihedral angle of 81.3" with the plane of the carbene
(N,CS,Phl), the phenyl ring an interplanar angle of 74.3"
with the latter plane. From the torsion angles (Phl,CS,N,C6
= 180" and Phl,CS,N,ClO = 4.9") it follows that there is a
flattening of the coordination geometry of the nitrogen atom
and thus a demonstrated double bond character for C5-N
(1.320(1) A) that is typical of aminocarbene complexes.
By reaction of 14 with phosphanes PR, (R = Et, cyclohexyl (cHex), Ph) one or two ethene ligands can be displaced,
X
N
14 + RzPCH2CH,PR2
-
2 C2H4
23, R =iPr
24,R = cyclohexyl
0.5 PhzPCH2CH2PPh2
14
C2H4
NHtBu
CGH,
y".
Phz
htBu
6
25
%
L
14
+ L,.,Ni = C
,N-H
17, L = C2H4 + PEt,
The results suggest a path by which the tetracarbenenickel(o) complex 3 might be formed.
18, L = CzH4 + PcHex,
1 9 , L = C2H4
+
20, L = 2 PPh,
21, L = 3 co
Angew. Chem. I n t . Ed. Engl. 30 (1991) No. 12
0 VCH
Received: July 31, 1991 [Z 4840 IEJ
German version: Angew. Chem. 103 (1991) 1711
PPh,
CAS Registry numbers:
11, 137057-22-8;13, 137041-55-5;14,137041-54-4; 23,137041-56-6; [Ni(cdt)],
12126-69-1.
Verlagsgesellschaft mbH. W-6940 Weinheim. 1991
OS70-0833/91/1212-1667$3.S0+.2S/O
1667
[I] U. Schollkopf, F. Gerhart, Angew. Chem. SO(1968) 842; Angew. Chem. Inl.
Ed. Engl. 7 (1968) 805.
[2j A. Mollbach, G. Wilke, unpublished.
(31 a) B. Marczinke, PhD Thesis, Universitat Bochum 1988; b) E. Bessler,
B. M. Barbosa, W. Miller. J. Weidlein, Z . Narurforseh. 8 4 6 (1991)
490.
[4J K. R. Porschke, unpublished.
[5] W. Kaschube, Disserlation, Universitat Bochum 1987.
[6] K . R. Porschke, G. Wilke, Chent. Ber. 117 (1984) 56.
[7] G. E. Niznik, W. H. Morrison 111, H. M. Walborsky, J. Org. Chem. 39
(1974) 600.
[8] All the new compounds gave correct elemental analyses. Procedure for 11:
A solution of LiC,H, (2.75 g, 30.6 mmol) in ether (100 mL) was treated
with tBuNC (3.3 mL, 29.2 mmol) and PMDTA (9.0 mL) at -25 "C. After
20 min, an orange precipitate separated out from the deep-red solution
which dissolved upon addition of a solution of [Ni(C,H,),] prepared from
[Ni(cdt)] (6.43 g, 29.1 mmol) in 50 mL of ether. After 12 h at - 78 "C a
yellow crystallizate was obtained which was isolated cold by suction,
washed with cold ether, and dried at - 30 "C in a high vacuum. Yield: 8.2 g
(62%). 'H NMR (200MH2, [DJTHF, -30°C): 6=1.27 (s, 9 H ;
C(CH,),), 1.93-2.09(rn,8H;C,H4),2.12(s, 12H;N(CH3),), 2.20(s, 3 H ;
NCH,), 2.30-2.40 (m, 8 H ; NCH,CH,N), 6.96-7.13, 5H; C,H,). ''C
NMR (75.5 MHz, [DJTHF, -30 "C): b = 260.0 (Ni=C), 155.3, 123.8,
128.1, 124.3 (C,H,), 58.5, 56.3 (NCH,CH,N), 57.8 (C(CH,),), 46.2
(N(CH,),), 43.4 (C,H,), 32.1 (C(CH,),), 44.2 (NCH,).
[9] E. 0. Fischei, F.R. Kreissl, E. Winkler, C. G. Kreiter, Chem. Ber. 105
(1972) 588.
[lo] Procedure for 13. A solution of 11 (1.29 g, 2.82 mmol) in T HF (20 mL)
was treated at -30 "C with 0.75 mL (2.86 mmol) of 4,7,13,18-tetraoxal,l0-diazabicyclo[8.5S]eicosane(Kryptofix 21 1) and 395 mg (2.8 mmol)
of CH,I in 10 mL of ether. A yellow precipitate was formed. The mixture
was warmed within 1 h to 0 "C and the ether removed in a high vacuum.
The residue was taken up in pentane and filtered. On cooling the red
filtrate to - 78 "C orange-red prismatic crystals separated out; these were
filtered off, washed with pentane, and dried in a high vacuum at 0 "C.
558mg(68%). 'HNMR(400MHz),[D8]THF, -30°C): 6 =1.52(s,9H;
C(CH,),), 2.18, 2.39 (m, 8 H ; C,H,), 2.99 (s, 3 H ; NCH,), 6.67-7.16 (m,
5 H ; C,H,). "C NMR (75.5 MHz, [DJTHF, -30 "C): 6 = 280.4 (Ni=C),
148.1, 120.5, 128.7, 124.6 (C,H,), 63.9 (C(CH,),), 48.6 (C,H,), 38.4
(NCH,), 29.4 (C(CH3),). Mass spectrum (70 eV/50 "C): m/z 289 ( M e )
(calcd. 289 for 58Ni).
[ll] Procedure for 14: A suspension of 11 (9.13 g, 20.1 mmol) in 80 mL ofether
was treated at -40 "C with a solution of acetylacetone (2.1 mL,
20.4 mmol) in ether (20 mL) and warmed to 0 "C. After 30 minutes the
precipitated lithium acetylacetonate was removed by filtration and the red
solution cooled to -78°C. The orange crystals that separated from the
filtrate were recovered by filtration, washed with pentane, and dried at
-20 "C in a high vacuum. 14 initially crystallized together with a half
equivalent of PMDTA, which was removed by recrystallization from pentane. 3.44 g (62%). 'H NMR (400 MHz, [DJTHF, -30 "C): 6 = 1.40 ( s ,
9 H ; C(CH,),), 2.21-2.35 (m, 8 H ; C,H,), 7.0-7.18 (m.5H; C,H,),9.27
(s, 1 H ; NH). I3C NMR (75.5 MHz, [DJTHF, 40°C): 6 = 277.3 (Ni=C),
150.4, 123.4, 128.5, 127.4 (C,H,), 57.4 (C(CH,),), 48.3 (C,H,), 30.1
(calcd. 275 for
(C(CH,),. Mass spectrum (70 eV/40 " C ) :m/r 275 (Me)
58Ni).
[12] B. E. Mann, B. F. Taylor: "C-NMR-Data for Organomerallic Compounds,
Academic Press, London 1981.
[13] Crystal structure analysis of 13 (C,,H,,NNi, M , = 290.1): crystal dimensions 0.20 x 0.20 x 0.42 mm, a = 10.002(2),b = 11.949(2),e = 12.295(3) A,
8=100.24(2)", V=1520.1 A3. T =-l73" C, ecaIcd
=1.27gcm-', p =
12.66 cm-', F(OO0) = 624 e, Z = 4, monoclinic, space group P2Ja
(No. 14), Enraf-Nonius CAD4 diffractometer, I = 0.71069 A, method of
measurement w-28,19 133 measured reflections (+ h, + k, + 4[EDD determination, X-XI, [sin8/J.],., 0.90 A- ', analytical absorption correction
(min: 1.253, max: 1.418), 9214 independent and 7121 observed reflections
[ I z 20(1)], 263 refined parameter; heavy atom method, H atom positions
observed and included in the least squares refinement, R = 0.039, R, =
0.035 w = l / u z (Fo), maximum residual electron density 0.91 e k ' . See
also Ref. [16].
1141 Procedure for 23:A stirred solution of 14(861.5 mg, 3.12 mmol) in toluene
(25 mL) was treated at -78 "C with a solution of 0.95 mL (3.1 mmol) of
dppe in 5 mL of toluene and the mixture warmed to - 10 "C for 2 h. The
solution was evaporated down in a high vacuum, and 20 mL of pentane
was added. Within a day at -78 "C,crystals precipitate. They were separated off, washed with pentane, and dried at room temperature in an oilpump vacuum. Yield: 927 mg (62%). M.p. 160 "C (decomp.). 'H NMR
(400MHz, [DJTHF, 27 "C): 6 = 0.08-1.35 (m, 24H; P(CH(CH,),), 1.25
(s, 9 H ; C(CH,),), 1.63-2.28 (m. 4H; P(CH(CH,),), 5.05 (d, 1 H ;
CH=NC(CH,),, 6.75-7.27 (m, 5H; C,H,). I3C NMR (75.5MHz),
[DJTHF, -30 "C): 6 =350.4, 124.9, 128.1, 121.9 (C,H,), 67.7
(CH=NC(CH,),), 56.1 (C(CH,),), 33.4 (C(CH,) 26.9, 26.5, 25.1, 23.2
(PC(CH,),), 21.1, 21.0, 20.4, 20.0, 19.7, 18.8, 17.4, 16.7(PC(CH3),), 20.7,
20.1 (PCH,CH,P). "P NMR (32.4 MHz, [D,]toluene, 38 T):6 = 63.6.
1668
0 VCH Verlagsgeselischaft mbH, W-6940 Weinheim, 1991
65.8 (d; Jpp= 66.0 Hz). Mass spectrum (70 eV/120 "C): m / z 481 (Me)
(calcd. 481 for 58Ni).
Crystal structure analysis of 23 (C,,H,,NiNP,, M , = 482.3): crystal dimensions 0.14 x 0.29 x 0.36 mm, a = 16.943(2), b = 17.420(2), e =
9.434(2) A, 8 = 94.39(1)", V = 2776.1 A',
= 1.15 gcm-',
p=
8.25 cm-', F(000) = 1048 e, Z = 4, monoclinic, space group Ce (No. 9),
Enraf-Nonius CAD4 diffractometer, 1 = 0.71069 A, method of measurement 0-28,6267measured reflections(+h,kk,+I), [(sin8/l.Jm,,0.65kl,
3140 independent and 2509 observed reflections [I > 2u(l)], 261 refined
parameters, heavy-atom method. H atom positions calculated and not
included int the least squares refinement, R = 0.031, R, = 0.033 [ w =l/u'
(Fo)l maximum residual electron density 0.40 eA-'. See also Ref. (161.
Further details of the crystal structure analyses are available on request
from the Fachinformationszentrum Karlsruhe, Gesellschaft fur wissenschaftlich-technische Information mbH, W-7514 Eggenstein-Leopoldshafen 2 (FRG), on quoting the depository number CSD-55642, the names of
the authors, and the journal citation.
Tetraalkoxytitanium-CarbeneComplexes
with Double Intramolecular Et,AI Bridging
By Carl Kruger. Richard Mynott, Carsten Siedenbiedel,
Ludwig Stehling, and Gunther Wilke *
Dedicated to Professor Kurt Schaffner
on the occasion of his 60th birthday
During investigations of the vaporization of elemental titanium in ketone and aldehyde matrices we have observed
C-C coupling with formation of titanium@) diolates. They
contain, in addition, end-on coordinated ketones or aldehydes. In the case of the di-tert-butyl ketone no coupling
takes place, and only two ketone molecules are bound sideon per Ti atom."] The product of a vaporization of titanium
in ketone surprisingly forms a catalyst with AIEt,, with which
high molecular weight polyethylene can be prepared. In this
connection we have investigated the synthesis and the behavior of titanium(1v) bisdiolates as components of Ziegler catalysts. Already in 1956 H . Martin['] was able to show that a
catalyst is formed from Ti(OnBu), and AIEt, which preferentially dimerizes ethene to butene at normal pressure, without significant amounts ofpolyethylene being formed. At the
same time Wilke foundL3]that butadiene affords high molecular weight 1,2-polybutadiene with this catalyst system.
L
'
2
Scheme 1. 1 is a titanium bisdiolate (see Text)
When Ti(OEt), is allowed to react with bicyclohexyL1,l'diol, ethanol can be removed, and a very sparingly soluble
titanium bisdiolate 1 is obtained, which according to its mass
. product of the same
spectrum is dimeric (m/z 880 ( M @ ) )The
[*] Prof. Dr. G. Wilke, Prof. Dr. C. Kruger, Dr. R. Mynott, C . Siedenbiedel,
L. Stehling ['I
Max-Planck-Institut fur Kohlenforschung
Kaiser-Wilhelm-Platz 1, W-4330 Miilheim a. d. Ruhr (FRG)
[ '1 Deceased.
0570-0S33191jt212-166X3 3.50+.25/0
Angew. Chem. Inr. Ed. Engl. 30 (1991) No. 12
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