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Hydride Abstraction From [C6H6Os(CO)(CH3)2] Does a Metal-bound Methyl Group Migrate Preferentially to a CO or to a CH2 Ligand.

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these compounds could contribute to an understanding of
catalysis by metal alloys.~"]
Received: February 16, 1987;
supplemented: April 27, 1987 [Z 2105 IE]
German version: Rngew. Chem. 99 (1987) 691
[I] M. Manassero, M. Sansoni. G. Longoni, 1.Chem. Soc. Chem. Commun.
1976. 919.
121 C . P. Horwitz, D. F. Shriver, Adu. Organomet. Chem 23 (1984) 219.
[3J P. Brun, G. M. Dawkins, M. Green, A. D. Miles, A. G. Orgen, F. G. A.
Stone, J . Chem. SOC.Chem. Commun. 1982. 926.
141 E. L. Muetterties, Bull. SOC.Chim. Belg. 85 (1976) 451.
151 a) E. L. Muetterties, J. Stein, Chem. Reu 79 (1979) 479; b) V. Ponec,
Caral. Rev.-Sci. Eng. 18(1978) 151; c) K. Kishi, M. W. Roberts, J . Chem.
Soc. Faraday Trans 71 (1975) 1715; d) A. Jones, B. D. McNicol, J . Carat. 47 (1977) 384; e) P. Biloen, J. N. Helle, w. H. Sachtler, J. Catal. 58
(1979) 95; f) H. H. Nijs, P. A. Jacobs, ibid. 66 (1980) 401; g) J. A. Rabo,
A. P. Risch, M. L. Poutsma, i6id. 53 (1978) 295.
[6J F. Richter, E. Roland, H. Vahrenkamp, Chem. Ber. 117 (1984) 2429.
[7J 'H-NMR (CDCI,, 298 K)-I: IR (hexane, cm-'): v=2065 vs, 2007 vs,
1989 m, 1977 w, 1890 w (CO); 'H-NMR: 6=5.28 (s, 10H).-Z: IR
(CH2CI2, cm - I ) : v=2082 vs, 2049 s, 2017 vs, 2002 s, sh, 1956 m, 1841 m,
1802 W, 1457 W; 'H-NMR: 6=5.67 (s, SH), 5.03 (s, 5H).-3: IR
(CDZCIZ,crn-'): v=2090 s, 2073 vs, 2020 vs, 2004 s, sh, 1993 m, 1958 m,
1847 W, 1801 V W , 1453 vW, 1419 V W ;'H-NMR: 6=5.72 ( s , SH), 5.23 (s,
5 H).
[SJ 2 : R u 4 M o 2 S O 1 4 C ~ ~ H
monoclinic,
I~~.
P 2 , / c , u = 16.!94(1), b = I1.559(2),
c = 17.420(3) A, 8= 113.67(1)0, Z = 4 , V=2968(1) A', 3202 reflections
( 1 > 3 0 ( I ) ) , R=0.029, 28,,,=48",
T=296 K, MoKn.Structure solution
by direct methods (MITHRIL).-3: R u ~ M o ~ S O , ~ C ~ ~ HCoH6,
, , , . Omo?.~
oclinic,
PZ,/m,
a = 13.045(3),
6= 15.308(4),
c = l0.055(1) A,
8= lll.79(1)o, Z=2, V= 1864(1)AZ, 2161 reflections (1>3u(l)),
R=0.040, 2&,,,,=48", T=296 K, Moan. Structure solution by direct
methods (MITHRIL). Further details of the crystal structure investigation may be obtained from the Fachinformationszentrum Energie, Physik, Mathematik GmbH, D-7514 Eggenstein-Leopoldshafen2 (FRG), on
quoting the depository number CSD-52314, the names of the authors,
and the journal citation.
191 a ) M. 1. Bruce, J. Organomet. Chem. 257 (1983) 417. b) M. I. Bruce, ibid.
242 (1982) 147. c) D. A. Roberts, G. L. Geoffroy in G. Wilkinson, F. G .
A. Stone, E. Abel (Eds.): Comprehensrue Orgonometallic Chemistry. Vol.
6, Pergarnon, Oxford 1982, Chap. 40.
[lo] a) H. Vahrenkamp, Adu. Organomer. Chern. 22 (1983) 169; b) H. Vahrenkamp, Phil. Trans. R . SOC.London A308 (1982) 17; c) C. von Schnering,
T. Albiez, W. Bernhardt, H. Vahrenkamp, Angew. Chem. 98 (1986) 474;
Angew. Chem. in!. Ed. Engl. 25 (1986) 479.
[ I I ] V. Ponec, Adu. Caral. 32 (1983) 149.
Hydride Abstraction From IC6H60s(CO)(CH3)21:
Does a Metal-bound Methyl Group Migrate
Preferentially to a CO or to a CH, Ligand?**
By Karin Roder and Helmut Werner*
Dedicated to Dr. Reinhard Schliebs on the occasion
of his 60th birthday
The concepts regarding the mechanism of the FischerTropsch process include the assumption that primary C-C
bond formation on the surface of the catalyst occurs by
combination of a CH, with a C O group or with a CH,
group formed in a hydrogenation step."] Model examples
for both of these processes are known using both monoand dinuclear metal complexes as starting material^.'^,^'
However, a remaining question is whether the C-C bond
forming step (a) or (b) of Scheme 1 is preferred, i.e., which
of the competing iigands CH, or C O couples with the CH3
group.
Scheme 1.
To answer this question, we have prepared compound 3
from 1 and studied its reaction with Ph3CPF6. Besides
CHPh, (detected by 'H-NMR and MS), only the ethylene
hydrido complex 5a is formed. In accord with the results
of previous investigations,'4' we propose that the trityl cation abstracts a hydride ion from one of the CH3 groups.
The intermediate 4 can then rearrange by CH, migration
(probably not by C H 2 in~ertion!'~'~)
to give the corresponding ethylmetal compound, from which complex 5a is
formed by P-hydride elimination. There is no evidence that
radical species (which have been observed during the formation of [(C5Hs)2WH(C2H4)]' from [(C5HS),W(CH3),]
and Ph,CPF,"]) are involved in this process.
3
1
4
1
50
The properties (color, thermal stability, conductivity)
and spectroscopic data of 5al6] are similar to those of the
analogous complex [C,H,0SH(C,H,)PMe,][PF6],'7' which
has recently been prepared by a completely different route.
For neither OsH(C2H4)complex has an equilibrium with
the corresponding alkyl isomer been detected by NMR
spectroscopy.
Deprotonation of the cation of 5a with NaH in tetrahydrofuran (THF) leads to the formation of 6 , which is
the first example of a half-sandwich type complex
[C&,OSLLq which contains two monodentate n-acceptor
ligands. Although the electron density at the metal atom in
6 is lower than that in the analogous complexes 7I7land
8,18]compound 6 can be protonated by strong acids. With
HBF, (in ether) 5b is obtained; however, NH,PF, does not
react with 6 to give 5a. Therefore, complex 6 , like 7, 8
and the compounds [C&OSL,] ( L = PPh,, P(OMe),)I8I
behaves as a mefal base. The metal basicity of compound 6
is comparable to that of IC6H6Ru(C2H4)PMe3] and
[C6Me6RU(CO)PMe~].191
I"] Prof. Dr. H Werner, DipLChem. K. Roder
lnstitut fur anorganische Chemie der Universitat
Am Hubland, D-8700 Wurzburg (FRG)
[**I
This work was supported by the Deutsche Forschungsgemeinschaft, the
Fonds der Chemischen lndustrie and Degussa AG. We highly appreciate the active collaboration of Miss I . Keupp in this project.
686
0 VCH Verlagsgesellschafr mbH, 0-6940 Weinheim. 1987
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Angew. Chem. In!. Ed. Engt. 26 (1987) No. 7
Using the bis(ethy1ene) complexes [C5H,M(C2H4)J
(M = Rh, Ir) as starting materials, Perutz and Haddleton et
al.""] have recently generated in low-temperature matrices
the compounds [C,H,M(C,H,)CO], which are structurally
similar to 6. These [CSHSM(C,H4)CO]complexes activate
C-H bonds (including methane!). Since [C,H,Os(C,H,),]
is as yet unknown, compound 6 is not accessible via this
route. Furthermore, it has not been possible to prepare 6
by the same method which leads to 7, 8 and the complexes [CeHoO~Lz]".81
(reduction of the corresponding haloosmiurn(ir) cation with NaCioHx). The transformation of
3 into 6 by stepwise abstraction of a hydride ion and a
proton represents a valuable alternative to previous synthetic routes and promises further possible applications.
The observation made in this study, that a CH, group prefers to migrate to a CH, instead of a C O group, can also be
regarded as indirectly supporting the "polymerization of
methylene groups" mechanism first proposed by Fischer
and Tropsch as long ago as 1926.1'11
(41 a) H. Kletzin, H. Werner, 0. Serhadli, M. L. Ziegler, Angew. Chem. 95
(1983) 49; Angew Chem. In,. Ed. Engl. 22 (1983) 46: b) H. Werner, H.
Kletzin, A. Hohn, W. Paul, W. Knaup, M. L. Ziegler, 0. Serhadli, J .
Organornet. Chem. 306 (1986) 227.
IS] J. C. Hayes, N. J. Cooper, J. Am. Chem. SOC. 104 (1982) 5570.
[6] 2 : M,=552 (MS): IR (KBr): v(CO)=1992 c m - ' : 'H-NMR ([D,Jdimethy1 sulfoxide): 6=6.43 (s).-3: M,=328 (MS); IR (KBr): v(CO)= 1925
c m - ' : ' H - N M R (C,,H,): 6=4.64 (s, C,,H6), 1.07 (s, CH?).--Sa: IR
(KBr): v(C0)=2020 c m - ' ; ' H - N M R (CD,N02): 6=6.87 (s, C,H,,), 3.31
(6,,) and 2.63 (&, AA'BB' spin system, N s 8 . 0 Hz) (C2H4). - 11.97 (s,
OsH); "C-NMR (CDlNOZ): 6= 172.94 (s, CO), 99.61 ( s , C,,H,,), 27.22 ( S ,
CZH,).-6: M,=326 (MS): IR (KBr): v(CO)=1878 c m - ' ; ' H - N M R
(C6H6): 6=4.80 (s, C6H6), 2.05 (m, probably AA'BB' system of higher
order, C2H,).
171 R. Werner, H. Werner, Chem. Ber. 116 (1983) 2074.
[8] R. Werner, H. Werner, Chem. Ber. 115 (1982) 3781.
191 Review: H. Werner, Angew. Chem. 95 (1983) 932: Angew. Chem. In!. Ed.
Engl. 22 (1983) 927.
[lo] a) D. M. Haddleton, R. N. Perutz, S. A. Jackson, R. K. Upmacis, M.
Poliakoff. J . Organornet. Chem. 311 (1986) C 15: b) D. M. Haddleton,
ibid. 311 (1986) C 2 1 ; c) D. M. Haddleton, R. N. Perutz, J . Chem. SOC.
Chem. Commun. 1986, 1734.
[II] F. Fischer, H. Tropsch, Brennsr.-Chem. 7 (1926) 97: see also Ref. [I].
Experimental
2 : A suspension of 1 (l.OOg, 0.96 mmol) in CH2C12 (60mL) was saturated
with CO in a Schlenk tube fitted with Nz inlet. After stirring for 20 h at room
temperature under a C O atmosphere, the solution was concentrated to ca.
5 m L and the product precipitated with hexane. The precipitate was separated from the solution, repeatedly washed with hexane, and finally dried in
vacuo; m.p. 197°C (decomp.); yield quantitative.
3 : A suspension of 2 (276 mg, 0.50 mmol) in benzene (5 mL) was treated
slowly at room temperature with 3.3 mL of a 0 . 6 ~solution of methyllithium
in ether (2.0 mmol). An orange-brown solution immediately formed which
was stirred for 10 min and then evaporated to dryness in vacuo. The residue
was treated with a few m L of benzenelhexane ( I : I ) , and excess of methyllithium was destroyed by careful addition of deactivated AlzOl (activity grade
V). After chromatography of the benzene/hexane solution on AI20, (activity
grade 111). a yellow fraction containing 3 was eluted with benzenelhexane
( 1 : 1). Removal of the solvent furnished 3 as a yellow microcrystalline powder: m.p. 130°C (decomp.); yield 63%.
5 a : A solution of 3 (75 mg, 0.23 mmol) in ether (3 mL) was treated dropwise
at - 78°C with a solution of Ph,CPF6 (89 mg, 0.23 mmol) in CH2Clz (3 mL).
After slow warming, the reaction mixture was stirred for 1 h at room temperature. The precipitation of a light-brown solid was completed by addition of
15 m L o f ether. The precipitate was separated from the solution, washed with
ether and hexane, and dried in vacuo: yield 91%.
6 : A suspension of 5a (107 mg, 0.23 mmol) in T H F (3 mL) was treated at
-78°C with NaH (cd. tenfold excess). After warming to room temperature,
the solution was stirred for 30 min (evolution of gas occurs), and the goldenbrown suspension was then reduced to dryness. The residue was extracted in
small portions with 20 m L of benzene/hexane ( I :I), the solution filtered,
and the solvent removed in vacuo. A yellow microcrystalline powder was
obtained: m.p. 98°C (dec.); yield 77%. The protonation of 6 with HBF, in
ether to give 5b proceeds quantitatively.
Received: February 17, 1987 [Z 2108 IE]
German version: Angew. Chem. 99 (1987) 719
[I] a) C. K. Rofer-DePoorter, Chem. Reu. 81 (1981) 447; b) W. A. Herrmann. Angew. Chem. 94 (1982) 118: Angew. Chem. Int. Ed. Engl. 21
(1982) 117; c) G . Henrici-Olive, S. OlivC in F. R. Hartley, S. Patai (Eds.):
The Chemistry ofthe MetalLCarbon Bond, Vol. 3, Wiley, New York 1985,
Chapter 9.
[2] CO + C H I : a) A. Wojcicki, Ado. Organornet. Chem. I 1 (1973) 87; b) F.
Calderdzzo, Angew. Chem. 89 (1977) 305: Angew. Chem. Int. Ed. Engl.
16 (1977) 299; c) E. J. Kuhlmann, J. J. Alexander, Coord. Chem. Reu. 33
(1980) 195: d ) T. C . Flood, Top. Stereochem. 12 (1981) 37; e) J. J. Alexander in F. R. Hartley, S. Patai (Eds.): f i e Chemistry of the Metal-Carbon Bond, Vol. 2, Wiley, New York 1985, Chapter 5.
[3] CH: + CH.<:a) R. C . Brady 111, R. Pettit, J . Am. Chem. SOC.102 (1980)
6181; h) K . Isobe, D. G. Andrews, B. E. Mann, P. M. Maitlis, J . Chem.
Sor. Chem. Commun. 1981. 809; 1. M. Saez, N. J. Meanwell, A. Nutton,
K. Isobe, A. Vazquez d e Miguel, D. W. Bruce, S. Okeya, D. G. Andrews,
P. R. Ashton, I R. Johnstone, P. M. Maitlis, J . Chem. SOC.Dalton Trans.
1986. 1565: c) D. L. Thorn, T. H. Tulip, J. Am. Chem. SOC.103 (1981)
5984; I). L. Thorn, Organometallics 4 (1985) 192: 5 (1986) 1897; d) J. C.
Hayes, G. D. N. Pearson, N. J. Cooper, J. Am. Chem. SOC. 103 (1981)
4648: e) Theoretical Work: H. Berke, R. Hoffmann, ibid. 100 (1978)
7224.
Anyew Chem In1 Ed Engl 26(1987) No. 7
Square Hg, Clusters in the Compound CsHg
By Hans-Jorg Deiseroth* and Axel Strunck
It is astounding that all the studies reported thus far on
the phase diagrams and magnetic properties of such apparently uncomplicated substances as the binary rubidium- and cesium-amalgams were carried out exclusively in
the first half of the century.''-31And, with the exception of
RbHg,
nothing has hitherto been reported about the
structures of these experimentally problematical compounds, which are of special interest in view of the possibility of weak bonding interactions between the electronically saturated mercury atoms. Extremely air-sensitive, lustrous single crystals and microcrystalline samples of the
compounds RbHg,, CsHg2, RbHgI'l and CsHg'"' have now
been prepared and structurally characterized for the first
time.[71Only CsHg will be reported upon in this communication.
The peritectically melting CsHg, probably the most mercury-deficient compound in the cesium-mercury system, is
characterized by isolated, square-planar Hg, clusters with
metallic Hg-Hg contacts (dH8.Hg==
300 pm) corresponding
to a formulation Cs,Hg, (Fig. 1). CsHg is thus the second
example of a structure type which was previously only
found in the isotypic KHg investigated in an older and
lesser known work.@' Cs,Hg, and &Hg4, however, differ
in a remarkable way: whereas the distances between the
square Hg-clusters in &Hga (336 pm) resemble those between the nearest neighbors in a - H g (300-340 pm), in
Cs,Hg, they are so large (419 pm) that there can be no direct Hg-interaction between neighboring clusters.
The crystal structure of CsHg depicted in Figure la
clearly reveals a columnar stacking of the Hg, clusters,
which are surrounded by larger rectangular stacks of Cs
atoms. The plane of the Hg, square is so strongly inclined
to the stacking axis [OOI] that there would appear to be the
possibility of there being shorter Hg-Hg distances within
the stacks. These distances are, however, considerably
longer than the shortest Hg-Hg distances between neighboring stacks.
[*] Prof. Dr. H.-J. Deiseroth, DiplLChem. A. Strunck
Fachbereich 8-Anorganische Chemie der
Universitat-Gesamthochschule
Postfach 10 1240, D-5900 Siegen (FRG)
0 V C H Verlagsgesellschaft mbH. D-6940 Weinheim. 1987
0570-0833/87/0707-0687$ 02 50/0
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c6h6os, doesn, bound, abstraction, group, ch2, ligand, methyl, metali, hydride, ch3, migrate, preferential
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