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Bis(tri-tert-butylsilyl)cadmium The First Silylcadmium Compound Isolated in Substance.

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+ LiNHR3
R'-Si F,-NR2Si(CH3)3
R'-SiF-NR'Si(CH,),
I
-LiF
HNR3
(1): R1 = C & , , R2 = CH(CH3),, R3 = C(CH3),
= R2 = R3 = C(CH,),
(2): R'
(I)
1
-1
-LIF'
'
(CH,),Si-N-Si-N-R3
0 I
H
J
+ LC4H9
f---
(2)
-L~F
( 3 ) : R' = C&5, R2 = CH(CH3),, R3 = C(CH3),
14): R1 = R2 = R3 = C(CH,),
-
~~
- - -~- - -
.-
-~
~-
tert-Butq.luminoisoprop).l( trim~thyl~il~l)umiiiofluoroplieiiylsiluii~
( 1) :
Yield 9 0 % ; b.p. 63"C/0.01 torr; MS (70eV): mje=326 (rel. int. 26%, M + ) ;
1R: 3400 c m - ' (SNH); ' H - N M R : 0.17 [Me& JHF=0.4Hz], 1.21 [Me2C,
JHF=1.2Hz], 1.24 [Me3C, JHF=0.3Hz], 3.45 [CH, JHt=2.0Hz], 7.6ppm
[C6H51.
rert-Butyluniirio-rert-but~~l(trimetl~yl~il~l)an~iiio-tert-but~ffluorojilui~~
(2)
Yield 75 %,: b.p. 66TiO.01 torr; MS (70eV): m,r=3?0 (1 2,.M'); IR: 3400
c m - ' (vNH); 'H-NMR: 0.30 [Me,Si], 0.89 [Me,C, JllF=1.3Hz], 1.26
[Me,CNH, JHF=0.6Hz]. 1.43 ppm [Me3CNSi, JHt=0.5 Hz]; "F-NMR:
- 32.5 ppm.
I -I.~oprop~I-2-dim~thgl-4-terf-huty/aii1iiio-4-plieii~/I -u~a-2,4-disiluc~clohutuiie
Bis(tri-tevt-butylsily1)cadmium:The First Silylcadmium
Compound Isolated in Substance[**J
By Lutz Rosch and Hartwig Miiller~]
Previous investigations['] on the synthesis of silylmetal
compounds according to
n R,SiH
(3).
Yield 70%; b.p. 69"C/0.01 torr; M S (70eV): m/e=306 ( X % , M'); IR: 3400
c m - ' (vNH); ' H - N M R : 0.28, 0.34 [MeSi]. 0.39 [CH,Si,], 1.08 [Me2C].
1.32 [Me,C], 1.5 [NH], 3.37 [CHI, 7.48ppm [C6H,].
+ R'"M
+n KH
-(R,Si),,M
R = E t . P h ; R ' = E t . Ph.rRti:
M = main group metal
have shown that this "hydride reaction" proceeds in the
I .3-Ui>( I ( T I - h u t ~ l ) - 2 - d 1 i i i e t l 1 ~ 1 - 4 - t e r r - h u t ~ l - 4 - 1 ~ i e t ~ i ~ l - I , 3 - d i u ~ a - 2 , 4 - d 1 . s i l uexpected
~ ~ ~ l ~ ~ - manner only under drastic conditions. The main
drawback of this method was that many of the silylmetal
hutwe ( 4 )
Yield 75 %; m.p. 102°C; MS (70eV): m,r=300 ( I ?!:,, M i ) ; ' H - N M R : 0.32,
compounds thus synthesized could not be isolated from the
0.35 [MeSi], I.0X [Me,CSi], 1.20 ppm [Me,CN].
'H-NMR spectra: 30% solution in CH2C12,TMS int.
"F-NMR spectra: 30% solution in CH2CI,. C 6 F 6 int.
Elemental analysis gave correct results for all compounds.
~
-~
-
-
~~
Experimental:
C4H9Li (0.11 mol, 15 % solution in hexane) is added dropwise with stirring at room temperature to 0.1 mol monoalkylaminofluorosilane [(Z), (Z)]. LiF and C,H,, split off in an
exothermic reaction. For completion of reaction the mixture
is heated to boiling for 12h. After removal of hexane the
heterocyclic products are distilled in a vacuum [(3)] or sublimed [ ( 4 ) ] .
reaction mixture but only their existence demonstrated on the
basis of secondary reactions-e.g. also in the case of the
only previously known organosilylcadmium compound, bis(triethylsilyl)~admium[~l.
Should in fact a hydride transfer be the determining factor
in the course of the reaction then polarization of the silane
hydrogen is of decisive importance; consequently, tri-tertbutyl~ilane[~'
[low Si-H stretching frequency at 2080 cm- ',
small 'J('H-29Si)coupling constant of 179.7 Hz and chemical
shift of 3.39 ppm rel. TMS] ought to'be a particularly effective
silylating reagent.
We have found that tri-tert-butylsilane if) reacts with diethylcadmium ( 2 ) in the molecular ratio 2 :I with loss of ethane already at 90°C :
2 (r-C,H,),SiH
Received: June 8, 1976 [ Z 512 IE]
German version: Angew. Chem. 88. 647 (1976)
CAS Registry numbers:
( I ), 60253-73-8; ( 2 ) , 60253-74-9; ( 3 1 , 60253-75-0; (41, 60253-76-1 :
C,HSSiF2NCH(CH,),Si(CH,),. 60253-77-2 ; C(CH,),SiF, NC(CH, J,Si(CH,)3,
60253-78-3; LiNHC(CH,),, 37828-549
(1)
+
(C,H,),Cd
-
[(t-C,H,),Si],Cd
(2)
+
2 CzH6
(3)
As reaction proceeds the liquid mixture of ( I ) and ( 2 )
gradually solidifies; colorless crystals are formed, which after
purification by recrystallization from benzene can be identified
by spectroscopic investigation and elemental analysis as bis(tritert-butylsily1)cadmium (3).
~-~
[I]
U . Klirigehirl and A . Meller. Chem. Ber. 109, 2430 (1916).
121 U . Kliityehiel and A. Mrllrr. Z . Anorg. Allg. Chem., in press.
[3] U . KImgehiel and A . Mrller, Angeu. Chem. 88. 307 (1976): Angew.
Chem. hit. Ed. Engl. 15. 312 (1976).
[4]
151
C . R . Bemiett and D. C . Brudley. J. Chem. Soc. Chem. Commun. 1974,
29.
U . Kliiiyrbiel and A . Meller, Z . Anorg. Allg. Chem., in press.
620.
[*] Dr. L. Rosch and Dipl.-Chem. H. Muller
lnstitut fur Anorganische und Analytische Chemie der Technischen Universitat
Strasac des 17 Juni 135. D-1000 Berlin 12(Germany)
[**I This work was supported by the Deutsche Forschungsgemeinschaft.
We thank Dr. R . Zeisherg of t h e lnstitut fur Organische Chemie der TU
Berlin for recording the "C-NMR spectra.
The 'H-NMR spectrum (60 MHz; rel. C6H6 int.) of (3)
shows only one signal at 1.33ppm (converted to TMS), which
expectedly exhibits no coupling with cadmium ("'Cd, I = 1/2,
rel. abundance 12.86 %; 'I3Cd, I = 112, rel. abundance
12.34%). In contrast the I3C-NMR spectrum (20 MHz; rel.
C6D6 int.) shows two signals at 95.06 and 102.58ppm, both
flanked by coupling satellites [2J("C-"""3Cd)=31
Hz,
3J('3C-11"1'3Cd)=11.4Hz]. N o Si-H stretching vibrations
are observed in the IR spectrum (solution in Nujol, CsI disks).
Experimental:
All operations were carried out under an atmosphere of
dry oxygen-free argon. The starting compounds (1) and (2)
were prepared by known methods[41.( I ) (7.5mmol) and (2)
(3.75 mmol) were transferred to a 25 ml flask furnished with
an argon inlet and a reflux condenser connected to a gas
burette via a bubbler. O n heating to 9 0 T , 156ml gas was
evolved within 24h (IR: C&; ca. 86 %). Unconsumed (1)
could be removed at 60°C/2.5 x 10- mbar. The crude product
was purified by recrystallization from benzene. (3) was
obtained as pale yellow crystals m.p. ca. 140°C (decomp.)
which turned green-black on exposure to air and moisture.
Received: June 8, 1976 [Z 513 IE]
German version: Angew. Chem. 88, 681 (1976)
CAS Registry numbers:
( I ) , 18159-55-2: ( 2 ) , 592-02-9; ( 3 ) , 60349-27-1: " C , 14162-74-4
r
--
~
N. S. Vva-anliii. Organomet. Chem. Rev. A3,323 (1968); N. S . Vvuzankiti,
E. N. Glatlrsher, S . P. Knriiran, G . A . Ra;iiuueu, and E . A . Arkhaiiyel'skayu,
Zh. Obshch. Khim. 38, 1803 (1968); R. A. Jacksoti, Chem. Commun.
1966. 827.
N. S. Vwzafikifi.G. A. RUZWUN,and V T Bln.hknr, Zh. Obshch. Khim.
35, 395 (1965).
M . P. D n d e and C . 71 Wcw, J. Am. Chem. SOC.97. 3777 (1975).
a ) M . Weidetihrirrh and W Peter, Angew. Chem. 87, 670 (1975); Angew.
Chem. Int. Ed. Engl. 14, 642 (1975); b) Houben-Weyl, Methoden der
Orgdnischen Chemie, Vol. I3/2a. Thieme-Verlag, Stuttgart 1973, p. 868.
Carbanion Complexes of Nickel(o)
By Klaus Jonas, Klaus Richard Porschke, Carl Kriiger, and
Yi-Hung ~ s a y [ * ]
Transition-metal(0) compounds in which simple carbanions
such as CH; o r C2H; are coordinated as electron donors
to the metal atom were, to our knowledge, previously
unknown".21. We report here on novel nickel(0) complexes in
which such a o - M o - C bonding is present.
During investigations on alkali metal compounds of nickelI31
we found that reaction of binary Nio-olefin complexes such
as (CDT)Ni or (COD)2Ni[41with organolithium compounds
LiR (Ni/LiR= 1 : 1) and ethylene in the presence of strong
(COD),Ni
+ LiK +
2 CZH,
+
EI2O
2 (CH~)ZN-CH~CH~-N(CH~)~
n-donor ligands such as tetrahydrofuran or N,N,N',N'-tetramethylethylenediamine'leads to complexes in which two ethylene molecules besides a carbanion ligand R- are bonded
to a nickel atom with formation of a R-Nio(C2H4)2 anion.
The complexes (1 ) are characterized by elemental analysis
and 'H-NMR data, as well as by reaction with ethanol or
carbon monoxide. With ethanol two equivalents of diamine
are liberated per equivalent of Li;.the ethyl compound ( I b )
yields the calculated amount of ethylene and ethane, while
the methyl compound ( 1 a ) yields also the calculated amount
of methane together with ethylene and ethane (from ethylene).
O n the other hand, the ethylene moiety in ( I a ) , ( I b ) and
(1 c) can also be displaced quantitatively (as C2H4)by carbon
monoxide.
In the 'H-NMR spectrum of (1) (in [D,]-THF) the signals
of the amine protons are not shifted compared to free amine;
it thus follows that the amine ligands initially coordinated
to the lithium are completely displaced by [D,]-THF. In
all three cases singlets are found for the protons of the ethylene
ligands coordinated to nickel, for (1 a ) at T = 8.26, ( I b ) at
~ = 8 . 4 2and for (I c) at r=8.34. The signals of the phenyl
protons in ( l c ) appear at r=2.4 and 3.4 (intensity ratio
2: 3). The methyl protons in ( 1 a ) are observed as a singlet
at T = 10.58, while the ethyl compound ( I b ) shows a triplet
for the methyl protons at ~ = 8 . 7 6and a quartet for the methylene protons at r=9.42 with J = 7.5 Hz. All 'H-NMR spectra
are essentially temperature-independent in the range - 80°C
to +2O"C. Exchange between complexed and added free ethylene is not observed.
The specific conductivities of complexes ( I ) are 1-2 x
R-' cm-' (0.25 M in T H F at -3O"C), and thus correspond
closely to the value quoted for LiC104 in T H F ; hence the
compounds are obviously largely ionic. Also in agreement
with this is the result of X-ray structure analysis, according
to
which
(la)
is
composed
of
separated
Li[(CH3)2NCH2CH2N(CH3)2]2cations and CH3Ni(C2H4)2
anions in the crystalline state.
Crystal data [ ( l a ) ] [ ' ] : a=10.022(2), b= 16.121(3),
c= 14.501(1)A; p=96.82(1)"; space group P21/n, Z = 4 ; 3395
reflections, 1694 of which are considered unobserved;
R = 0.069.
CT)
c3
- 2 COD
Fig. I . Crystal structure of the carbanion complex ( I a )
COD = 1 , 5 - ~ y ~ l 0 -
(lo),R = CH,
( I b ) , R = CzH,
( 1 ~ )R
. = CsH,
octadiene
-
['I
Dr. K. Jonas, Dr. K. R. Porschke, Dr. C . Kriiger [**I, and Dr. Y.-H.
Tsay [**I
Max-Planck-Institut Fir Kohlenforschung
Kaiser-Wilhelm-Platz 1, D-4330 Miilheim-Ruhr (Germany)
[**I X-ray structure analysis.
In (I a ) the two ethylene molecules together with the methyl
group are oriented exactly trigonal-planar about the nickel
atom (Fig. 1). The Ni-C1 o-bond with a value of 1.91 A
is unusually short16]. The short C=C bond lengths in the
ethylene indicate only weak bonding to the nickel. The two
diamine ligands surround the lithium cation tetrahedrally.
In the solid state the complex is one-dimensionally polymeric;
each lithium cation is situated equidistant between two NiCH3 units (Li-CI* 5.351 and 5.390A; Li-Ni* 5.777 and
5.800 8).
62 1
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