mission 0.5-0.9), 4973 independent reflections, 3863 observed (I > 3o(I)), R = 0.040, R, = 0.062, 100 refined parameters, residual electron density 2.5 e k ' on the crystallographic twofold axis, 1.8 A distant from both Co atoms. Further details of the crystal structure analyses are available on request from the Fachinfonnationszentrum Karlsruhe, Gesellschaft fur wissenschaftlich-technische Information mbH, W-7514Eggenstein-Leo- poldshafen2 (FRG), on quoting the depository number CSD-55400, the names of the authors, and the journal citation.

[7] H. Werner, A. Salzer, Angew. Chem. 84 (1972) 949; Angew. Chem. Inr. Ed. Engl. 11 (1972) 930.

[8] A. W. Duff, K. Jonas, R. Goddard, H. J. Kraus, C. Kruger, 1 Am. Chem. SOC. 105 (1983) 5479.

[9] W. M. Lamanna, W. B. Gleason, D. Britton, Organometallics 6 (1987) 1583.

[lo] A. R. Kudinov, M. I. Rybinskaya, Y T. Struchkov, A. I. Yanovskii, P. V. Petrovskii, J. Organomet. Chem. 336 (1987) 187.

Ill] J. W. Lauher, M. Elian, R. H. Summerville, R. Hoffmann, 1 Am. Chem. SOC. 98 (1976) 3219.

[12] F. Mark, MPI fur Strahlenchemie, Miilheim a. d. Ruhr, unpublished. [13] a) R. E. Ginsburg, L. M. Cirjak, L. F. Dahl, J. Chem. Soc. Chem. Commun.

1979,468; Inorg. Chem. 21 (1982) 940; b) M. Schulz, S. Stahl, H. Werner, 1 Organomet. Chem. 394 (1990) 469.

[14] a) P. Louca, J. A. K. Howard, Acta Crystallogr. Sect. C43 (1987) 1908; b) I. Bernal, J. D. Korp, G. M. Reisner, W A. Herrmann, 1 Organomet. Chem. 139 (1977) 321.

[15] J. R. Blackborrow, D. Young: Metal Vapour Synthesis in Organometallic Chemistry, Springer, Berlin 1979, Chap. 1.

[16] For the detection of reactive M-L fragments at low temperatures see: M. P. Andrews, S. M. Mattar, G. A. Odn, 1 Phys. Chem. 90 (1986) 744.

[17] M. P. Andrews, G. A. Ozin, J. Phys. Chem. 90 (1986) 1245. [18] W. M. Lamanna, J. Am. Chem. Soc. 108 (1986) 2096. [19] P. L. Timms, Angew. Chem. 87(1975) 295; Angew. Chem. Int. Ed. Engl. 14

(1975) 273.

The Cluster Anion [Ru,H(CO),,S,J- : A Planar Hexanuclear Metal Framework with Almost Perfect C,, Symmetry By Urf Bodensieck, Helen Stoeckli-Evans, and Georg Suss-Fink*

The structure analysis of the osmium complex [Os,(CO),,{P(OMe),},] by Lewis et al."] showed that a hexanuclear cluster framework can be planar. Although sev- eral such "raft" clusters have been synthesized since then, the planar arrangement of the metal atoms in a hexanuclear cluster is more the exception than the rule.t21

In an attempt to extend the activation of C,,,-H bonds observed in the rutheniumcarbonyl-alkylthiourea systemt3] to methane, we were surprised to obtain the new cluster anion [Ru,H(CO),,S,]- (l), which contains an approxi- mately planar hexanuclear ruthenium skeleton with C,, sym-

metry. Anion 1, which has three outer Ru,S tetrahedrons enclosing an inner Ru,H tetrahedron, captures the imagina- tion by the aesthetics of its molecular architecture.

[*I Prof. Dr. G. Suss-Fink, Prof. Dr. H Stoeckli-Evans, U. Bodensieck Institut de Chimie, Universite de NeuchPtel Avenue de Bellevaux 51, CH-2000 NeuchPtel (Switzerland)

It is unclear how the cluster anion 1 arises on treatment of [RU,(CO)~~] with tetramethylthiourea in an inert atmo- sphere (60 bar methane or nitrogen) in THF solution at 150 "C; during workup of the reaction mixture it precipitates as the tetramethylformamidinium salt from dichloromethane. It does not form under ambient pressure.

The single-crystal X-ray structure analysis of l I 4 ] (Fig. 1) shows the almost planar metal framework in the form of a large triangle comprising four small triangles. The outer

Fig. 1. View from above (top) and from the side (bottom) of the cluster anion [Ru,H(CO),,S,]- (1) (ORTEP, 50% probability ellipsoids, C atoms of CO ligands are indicated by numbers only). Important atomic distances [A] and angles I"]: Ru(l)-Ru(2) 2.779(1), Ru(l)-Ru(6) 2.76711). Ru(2)-Ru(3) 2.776(1), Ru(2)-Ru(4) 3.027(1), Ru(2)-Ru(6) 3.003(1), Ru(3)-Ru(4) 2.790(1), Ru(4)- Ru(5) 2.763(1), Ru(4)-Ru(6) 3.034(1), Ru(5)-Ru(6) 2.772(1), Ru(l)-S(l) 2.302(1), Ru(2)-S(l) 2.384(1), R@)-S(2) 2.370(1), Ru(3)-S(Z) 2.303(1), Ru(4)- S(2) 2.375(1), Ru(4)-S(3) 2.372(1), Ru(5)-S(3) 2.308(1), Ru(6)-S(I) 2.379(1), Ru(6)-S(3) 2.371(1); Ru(Z)-Ru(l)-Ru(6) 65.58(1), Ru(l)-Ru(Z)-Ru(3) 157.92(2), Ru(~)-Ru(Z)-RU(~) 57.01(1), Ru(~) -Ru(~) -Ru(~) 57.27(1), Ru(4)- Ru(2)-Ru(6) 60.41(1), Ru(~) -Ru(~) -Ru(~) 65.89(1), Ru(~) -Ru(~) -Ru(~) 56.84(2), Ru(~) -Ru(~) -Ru(~) 59.40(1), Ru(~)-Ru(~)-Ru(~) 153.32(2), Ru(5)- Ru(4)-Ru(6) 56.92(1) Ru(~)-RU(~)-RU(~) 66.48(2), Ru(l)-Ru(6)-Ru(2) 57.40(2), Ru(I)-Ru(~)-Ru(~) 156.63(2), Ru(~) -Ru(~) -Ru(~) 60.19(1), Ru(4)- Ru(6)-Ru(5) 56.60(1).

three small triangles are each capped by a p,-sulfido ligand, while the inner Ru, triangle is capped on the opposite side of the plane to the sulfido ligands by a p,-hydrido ligand. The ruthenium atoms Rul, Ru3, and Ru5, situated at the comers of the large triangle, lie on average 0.55 A out of the plane defined by Ru2, Ru4, and Ru6, on the side of the sulfido ligands.

The unusually high-field NMR signal (6 = - 33.36) for the hydrido ligand indicates that it is p,-bridging. In con- trast, the anion [Ru,H(CO),,(OCNMe,),]- (2) synthesized by Kaesz et al. contains a pz-hydrido ligand (6 = - 17.08), and the hexanuclear metal framework is folded.t51 In anion

1 126 0 VCH Verlagsgeselischaft mbH, W-6940 Weinheim. 199f 0S70-0833~91/0909-1126 8 3SO+ ,2510 Angew. Chem. Int. Ed. Engl. 30 (199f 1 No. 9

1 the distances between the ruthenium atoms which define the outer triangle are on average shorter (2.77 A) than those of the inner triangle (3.02 A). In the six-membered metal ring described for anion 2, however, the Ru-Ru distances of the inner triangles (3.22 A) are clearly longer. This is explained by only a partial transannular interaction in 2.[51

The hexanuclear ruthenium skeleton in 1 is stabilized by 15 CO ligands. Every Ru atom bears an axial CO ligand, while Ru2, Ru4, and Ru6 are each bonded to one and Rul, Ru3, and Ru5 to two additional equatorial CO ligands. The three p,-sulfido ligands are situated on the same side of the plane of metal atoms. The p,-hydrido ligand must therefore lie on the other side for steric reasons, as the space-filling model shows (Fig. 2).

Fig. 2 SCHAKAL representation [6] of the cluster anion [Ru,H(CO),,S,]- (1) (Ru yellow, S green, H gray, C blue, 0 red).

Experimental Procedure All steps were performed under a N, atmosphere in dried, N,-saturated sol- vents. [Ru,(CO),,] (320 mg, 0.5 mmol) and (Me,N),CS (86 mg, 0.65 mmol) were dissolved in THF (20 mL) in a stainless steel autoclave (working volume 100 mL); the mixture was pressurized with methane (65 bar) and heated to 150°C under constant stirring. After 2 h the reactor was cooled, the pressure released, and the red-brown solution evaporated to dryness. The residue was taken up in dichloromethane and anion 1 precipitated as the [(Me,N),CH]+ salt in the form of red-brown crystals. Yield: 38mg (14%). IR(THF): i[cm-’] = 2079w, 2051vs, 2001vs, 1987(sh)m, 1933vw (v(C0)). ‘H NMR (CDCI3,200MHz):6=8.04(s,lH;CH),3.53(s,br,6H;Me),3.38(s,br,6H; Me), - 33.36 (s, 1 H; Ru,H). Satisfactory C, H, N analyses.

Received: May 6, 1991 [Z4613 IE] German version: Angew. Chem. 103 (1991) 1147

CAS Registry numbers: [(Me,N),CH] [l], 135707-57-2; [Ru,(CO),,], 15243-33-1 ; (Me,N),CS, 2782- 91-4.

[l] R. J. Goudsmit, B. F. G. Johnson, J. Lewis, P. R. Raithby, K. H. Whitmire, J. Chem. SOC. Chem. Commun. 1981 640.

[2] D. M. P. Mingos, A. S. May in D. F. Shriver, H. D. Kaesz, R. D. Adams (Ed.): The Chemistry of Metal Cluster Complexes, VCH Publishers, New York 1990, p. 52.

[3] U. Bodensieck, H. Stoeckli-Evans, G. Suss-Fink, J. Chem. SOC. Chem. Com- mun. 1990, 267.

[4] X-ray data: Stoe-Siemens AED2 four circle diffractometer (Mo,,, graphite monochromator, 1 = 0.71073 A, o/O-techniques), solution and refinement with NRCVAX [7]. [(Me,N),CH]+ salt of I: space group P2,/n, a =

Z = 4 , ~ . . , . ~ . = 2 . 3 8 l g c m - ~ , p = 18.6m-1,0,,,=250;4803independent reflections, numerical absorption by SHELX-76 [S] (transmission factors 0.643 (max) and 0.450 (min)), index limits h: - 13/13, k : 0/19, I : 0121; 4685 reflections with I > 3 u(I); although several hydrogen atoms could be deter- mined from difference maps, all were placed in calculated sites ( Vlso = Ueq,=] + 0.01). The hydrido hydrogen atom was found in the last difference map. Its coordinates were fixed and only its Vi,, value was refined

11.580(1), b = 16.264(1),~ = 18.174(3) A,p = 93.45(1)”, V = 3416.6(7) A,,

(0.074 A*). Refinement with weighted anisotropic temperature factors for the non-hydrogen atoms, least-squares method, R = 0.029, R, = 0.046,

difference map 0.57(max) close to a ruthenium atom and - 1.33 r n i r ~ A - ~ . Further details of the crystal structure investigation may be obtained from the Cambridge Crystallographic Data Centre, University Chemical Labo- ratory, Lensfield Road, GB-Cambridge CB2 1EW on quoting the names of the authors and the journal citation.

[5] N. M. Boag, C. B. Knobler, H. D. Kaesz, Angew. Chem. 95 (1983) 243; Angew. Chem. Int. Ed. Engl. 22 (1983) 249; Angew. Chem. Suppl. (1983) 198.

[6] E. Keller, SCHAKAL 88, a FORTRAN Programfor the Graphical Repre- sentation of Molecular and Crystallographic Models, University Freiburg 1988.

[7] E. J. Gabe, Y. Le Page, J.-P. Charland, F. L. Lee, NRCVAX, an Inferactive Program sysremfor Structure Analysis, J. Appl. Cryst. 22 (1989) 384.

[8] G. M. Sheldrick, SHELX-76, Programfor Crystal Structure Determination, University of Cambridge 1976.

w - l = u 2 (F,) + 0.0025 (e); residual electron density in the last density

On a Metathesis Reaction of Tetrathiafulvalene (TTF) ** By Henning Hopf,* Martin Kreutzer, and Peter George Jones * Dedicated to Professor Horst Prinzbach on the occasion of his 60th birthday

We recently reported“’ an efficient method for the prepa- ration of cyano(ethyny1)ethenes of type 1 and described their behavior as dienophiles in [2 + 41 cycloadditions. Because of the electron-withdrawing effect of the cyano substituents on the n-electron system, these compounds are potential accep- tors for charge-transfer (CT) complexes, those with tetrathia- fulvalene (2) and related compounds being of particular in- terest. Compound 2 is known to form electrically conducting “organic metals” with a large number of acceptor sys-

31 We therefore allowed the enyne 1 a to react with 2

R C N

P h - C E C C 0 2 E t

H

+ [:#”I S

2

NC

3

A -

R CN

Ph-CEC CO2Et

H

for two days in refluxing toluene and thereby obtained high- ly lustrous, black-violet crystals (77 YO). An X-ray structure analysis showed, however, that the product was not the ex- pected CT complex but, surprisingly, the covalent com- pound 4a (Fig. Its structure in the crystal is character-

[*] Prof. Dr. H. Hopf, Dip].-Chem. M. Kreutzer Institut fur Organische Chemie der Universitat Hagenring 30, W-3300 Braunschweig (FRG) Prof. Dr. P. G. Jones Institut fur Anorganische und Analytische Chemie der Universitat Hagenring 30, W-3300 Braunschweig (FRG)

[**I New Planar R Systems, Part 3. This work was supported by the Fonds der Chemischen Industrie and by BASE Part 2: H. Hopf, M. Kreutzer, P. G. Jones, Chem. Ber. 124 (1991) 1471.

4 a b

d C

Angew. Chem. Int. Ed. Engl. 30 (1991) No. 9 0 VCH Verlagsgesellschaft mbH, W-6940 Weinheim, 1991 0570-0833/91/0909-f127 $3.50+.25/0 1127