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Dimeric [Cp2Zr(CH2O)] a Novel (2-Formaldehyde)metal Complex from Carbon Monoxide.

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Dimeric [Cp,Zr(CH,O)],
a Novel ($-Formaldehyde)metal Complex
from Carbon Monoxide **
shorter than those connecting the monomeric ($CH,O)ZrCp, units. The C - 0 bonds are long; the Zr-C
distance in the three-membered ring is typical for a ZrC+
single bond. The (CH,-0)Zr units in 5 have metallaoxirane
character. I6a,
-
By Gerhard Erker, * Ursula Hoffmann, Roland Zwettler,
Peter Betz, and Carl Kruger
In the temperature range of interest for metal-catalyzed
reactions in the condensed phase the formation of formaldehyde from H, and CO is endothermic,['] whereas the formation of $-formaldehyde ligands in the coordination sphere
of a metal is usually exothermic. Nevertheless, only a few
examples of (qZ-CH,O)ML, complexes are so far known in
which the formaldehyde unit was synthesized by means of a
We present here the very produccarbonylation reaction. IZ1
tive synthesis of a reactive (q2-forma1dehyde)zirconocene
complex and describe some fundamental reactions of the
metallaoxirane moiety.
According to FEoriani et al.[31carbon monoxide is hydrozirconated at room temperature and ambient pressure to
give the dinuclear complex 1. The stable substitution product
2 can be prepared by reaction of 1 with 2 molar equivalents
of phenyllithium. I4] Not unexpectedly, the reaction with
methyllithium proceeds somewhat differently. Presumably,
in this case the methyl-bridged compound 3 is formed as
an intermediate, which readily decomposes into its mononuclear organometallic components under the reaction conditions. We have isolated dimethylzirconocene 4 (quantitative
yield) and dimeric (q2-forma1dehyde)zirconocene 5 (67 %)
as stable reaction products.
2 PhLi
Cp2Zr-0-ZrCpz
I
CI
CI
'
-
Fig. 1. Molecular structure of 5 in the crystal. Selected bond lengths [A] and
Z r - 0 2.103 ( 2 ) , Zr-C1 2.243 (3), C1-0 1.395 (4), Zr*-0 2.200 (2);
angles
0-C1-Zr 65.9 ( 2 ) , C1-0-Zr 76.8 (2), C1-Zr-0 37.3 (I), Zr*-0-Zr 109.5 (l),
Zr*-O-Cl 173.5 (2). 0'-Zr-0 70.5 (1).
r]:
-
CpsZr-0
I
Ph
Thermolysis (170 "C, 3 h) of the dimer 5 affords the known
cyclotrimeric compound [(CH,-O)ZrCp,], .
Complex 5
adds to many carbonylmetal complexes with opening of the
reactive Zr-C bond of a metallaoxirane unit. At room temperature, 5 reacts with CpCo(CO), selectively to give the
adduct 6. 8b1 It also reacts with alkyl- and hydrido-aluminum complexes; upon reaction with diisobutylaluminum
hydride at room temperature it forms the metallacyclic adduct 7[7c1
(Fig. 2). An X-ray structure analysis revealed that
-ZrCpz
I
Ph
2
17b3
2 CH3Li
According to the results of an X-ray structure analysis,[51
in the complex 5 two (q2-forma1dehyde)zirconocene units
are coupled to each other via their oxygen atoms, using the
available lateral coordination sites at the bent metallocene.
The Zr - 0 bonds in the three-membered ring are somewhat
[*I
[**I
Prof, Dr. G. Erker, DipLChem. U. Hoffmann. Dipl.-Chem. R. Zwettler
Institut fur Organische Chemie der Universitit
Am Hubland, D-8700 Wiirzburg (FRG)
Dr. P. Betz, Prof. Dr. C. Kriiger
Max-Planck-Institut fur Kohlenforschung
Kaiser-Wilhelm-Platz 1, D-4330 Miilheim a.d. Ruhr (FRG)
This work was supported by the Fonds der Chemischen Industrie. the
Deutsche Forschungsgemeinschdft, and by Alfred-Krupp-von-Bohlenund-Halbach-Stiftung.
630
0 V C H Verlagsgesellschaft mhH, 0-6940 Weinheim,1989
c11
Fig. 2 . Molecular structure of 7 in the crystal. Selected bond lengths [A] and
angles ["I: Zrl-01, 2.153 (3). Zrl-C1 2.248 (5) C1-01 1.430 (6), Zr2-02 2.156
(3). Zr2-C2 2.230 ( 5 ) . C2-02 1.430 (6), A1-01 1.815 (3), A1-02 1.811 (3); Zrl01-A1 138.6 (2), Zr2-02-AI 137.9 (2).
the (q'-formaldehyde)zirconocene units in 7 also have pronounced metallaoxirane character. L91
0570-0X33/89j0505-0630
$02.50jO
Angew. Chem. Int. Ed.Engl. 28 (1989)No. 5
Co(C0)Cp
[5] 5 . C,,H,,O,Zr,,
M = 502.9, monoclinic, P2,In. a = X.9177 (6).
h = 7 . 7 6 7 0 ( 6 ) , c = 1 3 . 9 1 7 ( 1 ) ~ , ~ = 9 0 . 1 0 2 ( 7 ) "V. = 9 6 4 . 0 A 3 , 2 = 2 ,
= 1.73 gcm-'. ~ ( M o ) =
~ .10.76cm-I, Enraf-Nonius diffratomeheavy atom
ter. 4340 measured reflections, 3352 observed ( I z 2 o
method, hydrogen positions calculated and not refined, R = 0.047,
R , = 0.071 for 11X pdrdmterS[9b].
[6] Cf. G. Erker, U. Dorf, P. Czisch. J. L. Petersen, Orgunorneidics 5 (1986)
668; G. Erker, P. Czisch, R. Schlund, K. Angermund, C. Kriiger, Angew.
Chem. 98 (1986) 356; Angew. Chem. Inr. Ed. Engl. 25 (1986) 364: G. Erker,
K. Kropp, C. Kruger, A.-P. Chian, Chem. Ber. if5 (1982) 2447.
[7] 5 : m.p. = 220 "C (dec.); correct elemental analysis (C. H); MS (70 e V ) : m/r
500 ( M e , 18%), 470 (MQ - CH,O, loo), 390 (33). 220 (60); 'H NMR
(200 MHz, CDCl,): 6 = 5.89 (Cp), 2.42 (CH,); "C NMR (50 MHz. CDCl3): 6 = 107.8 ('J(CH) = 171 Hz, Cp), 64.0 ('J(CH) = 153 Hz, CH,); b)
6: yield 81 %, m.p. 160'C (dec.); correct elemental analysis (C. H); 'H
NMR (200 MHz, [D,]benzene): 6 = 5.81,5.45 (each s, each 10H, ZrCp,),
5.08 (s, 5H, CoCp), 4.34 (s, 2H, CH,), 2.58 (s, 2H, ZrCH,); I3C NMR
(50 MHz, [DJbenzene): 6 = 290.0 (carbene C), carbonyl C not observed,
113.0(ZrCp,), 107.8 (ZrCp,), 95.4 ('J(CH) = 143 Hz, CH,), 84.5 (CoCp).
66.4 ('J(CH) = 154Hz, ZrCH,); IR (KBr): F(C0) = 1905 crn-l; c) 7:
yield 41%, m.p. 170°C (dec.); MS (70eV): mi; 642(Me, 0.13%). 585
(Me CH,CHMe,, 28%). 220 (Cp,Zre, 66%); 'H NMR (200 MHz,
[DJbenzene): 6 = 5.57 (s, 20H. Cp), 2.39 (s, 4H, ZrCH,), 2.21 (m. 2H,
CH,CH), 1.32 (d, 12H, CH(CH,),), 0.15 (d, 4H, AICH,CH). - 3.66 (s,
l H , ZrHZr); "C NMR (50 MHz, [DJbenzene): 6 = 105.8 (Cp). 53.0
('J(CH) = 156 Hz, ZrCH,), 29.0 ('J(CH) = 123 Hz, CHCH,), 26.8
('J(CH) = 118 Hz, CHCH,), 22.1 (broad, AICH,CH).
[81 a) K. Kropp. V. Skibbe. G. Erker. C. Kriiger, J. Am. Chem. Soc. 105 (1983)
3353; b) cf. G. Erker, R. Lecht, J. L. Petersen, H. Bonnemann, Organumerullics 6 (1987) 1962.
M = 645.1, trichlinic, Pi, u = 10.217 (l),
[91 a) 7: C,,H,,AlO,Zr,,
h = 11.281 ( 2 ) , c = 13.844(2)A,x= 1 0 0 . 3 7 ( 1 ) , ~ = 9 0 . 1 2 ( 1 ) , ~106.36
=
(1)",V=1503.7~3,2=2,~bor=1.42gm~~,~(Mo,.)=7.33cm~'.Enraf-Nonius dlffractometer, 7145 measured reflections. 4601 observed
( I 2 u (4). R = 0.042, R, = 0.041 for 445 parameters, b) further details of
the crystal structure investigations are available on request from the Fachinformationszentrum Energie, Physik, Mathematik GmbH, D-7514 Eggenstein-Leopoldshafen 2 (FRG), on quoting the depository number
CSD-53731, the names of the authors, and the journal citation.
[lo] R. M. Waymouth, B. D. Santarsiero, R. J. Coots, M. J. Bronikowski,
R. H. Grubbs, J. Am. Chem. SOC.108 (1986) 1427.
(n),
cp2zr-o
I
1
O--ZrCp2
\ /
CH2
7
6
The reactions of 5 presented here confirm and extend the
emerging consistent picture of the special behavior of metallaoxirane compounds of the early transition metals. c6, a,
Received: October 12, 1988;
revised: December 27, 1988 [Z 3004 IE)
G e m a n version : Angew. Chem. I01 (1 989) 644
CAS Registry numbers:
1. 83385-36-8; 4, 12636-72-5; 5 , 83385-20-0; 6, 119747-76-1; 7, 119747-77-2;
I
[(<TI, O)ZrCp,l,, 85442-82-6; CpCo(CO),,
~
11) E. L. Muetterties, J. Stein, Chem. Rev. 79 (1979) 479; C. K. Rofer-De
Poorter, ihid. 81 (1981) 447; see also J. F. Knifton, J. Am. Chem. SUC.I03
(1981) 3959.
[2] G. Erker, Acc. Chem. Res. 17 (1984) 103, and references cited therein;
R. E. LaPointe, P. T. Wokzdnski, J. Am. Chem. SOC.108 (1986) 3535;
P. T. Wolczanski, R. S. Threlkel, J. E. Bercaw, ibid. 101 (1979) 218; P. T.
Barger, J. E. Bercaw, Organometallics 3 (1984) 278; T. Beringhelli,
G . D'Alfonso, G. Ciani. H. Molinari, &id. 6 (1987) 194.
13) G. Fachinetti, C. Floriani, A. Roselli. S. Pucci, J. Chem. Soc. Chem. Cummun. 1978, 269: S. Gambarotta, C. Floriani, A. Chiesi-Villa, C. Guastini,
J. A m . Chem. SOC.105 (1983) 1690.
[4] G. Erker. K. Kropp, Chem. Ber. 115 (1982) 2437.
~
BOOK R E V I E W S
Preparative Acetylenic Chemistry (Series: Studies in Organic
Chemistry, Vol. 34). 2nd Edition. By L. Brandsma. Elsevier, Amsterdam 1988. x, 322 pp., hard cover,
HFI 220.00.-ISBN 0-444-42960-3
This book is a completely reviewed and updated version of
the original 1971 publication, and has been enlarged by more
than 100 pages. It is aimed at advanced students and preparative organic chemists.
As in other books by the same author (L. Brandsma,
H. D. Verkruijsse: Synthesis of Acetylenes, Allenes and Cumuienes, Elsevier, Amsterdam 1981 ; L. Brandsma, H. D.
Angen. Chc,m. I n i . Ed. Engl. 28 (1989) No. 5
Verkruijsse: Preparative Polar Organometallic Chemistry,
Springer, Berlin 1987), all the preparative methods contained here have been carefully tested. The reader benefits
from the author's many years of experience in acetylenic
chemistry. The recommended reaction conditions take into
account the reactivities of the starting compounds and intermediates. In practice a lack of knowledge of reactivities often
leads to reactants being unnecessarily stirred under reflux for
hours, despite the fact that the reaction is in fact completed
within a few minutes. Much time and money can be saved
when accurate information on reaction durations and reproducible laboratory recipes are available.
The topics covered in the book's twelve chapters are as
follows. Chapter 1 gives practical advice of a general nature,
and describes a number of extremely useful tricks from the
author's wealth of experience. The rest of the chapters are:
2. Metallation of Acetylenes; 3. Functionalization of Metallated Acetylenes with Alkyl Halides, cl-Haloethers, Epoxides
and Alkyl Orthoformates; 4. Ethynylation and Alkynylation
of Carbonyl Compounds; 5. Carboxylation, Alkylation and
Related Reactions; 6. Silylation, Stannylation and Phosphorylation; 7. Sulfenylations and Related Reactions; 8. Halogenation and Cyanation; 9. Introduction of the Triple Bond
by Elimination and Addition-elimination Reactions; 10.
Couplings of Acetylenes Assisted by Copper and Palladium
Compounds; 11. Base-promoted Interconversions of
Acetylenes; 12. Miscellaneous Preparations of Acetylenic
Derivatives. More than 500 acetylene derivatives, which can
ic3 VCH Verlu~sgiwllschafimhH, D-6940 Weinheim, 1989
0570-0833~R9j0505-0631
S 02.5010
63 1
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