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Novel Metal Thiolates [Co2(SC3H7)5] the First Complex with Face-Sharing MS4 Tetrahedra.

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from yellow to red and finally to green. After the reaction mixture had been
stirred for about 1 h, a black precipitate was filtered off. The filtrate was kept
at -20% and after a few days small, red-green needles separated from the
solution.
Received: June 2, 1992 [Z5381IE]
Germdn version: Angew. Chem. 1992, 104, 1380
CAS Registry numbers:
2, 143306-07-4; 4, 143293-26-9; 6. 143293-28-1
[l] a) R. L. Robson, R. R. Eady, T. H. Richardson, R. W. Miller, M. Hawkins,
J. R. Postgate, Nature 1986,322,388; b) B. J. Hales, E. E. Case, J. E. Morningstar, M. F. Dzeda, L. A. Mauterer, Biochemistry 1986, 25, 7251.
[2] a) C. D. Garner, J. M. Arber, I. Harvey, S. S. Hasnain, R. R. Eddy, B. E.
Smith, E. de Boer, R. Wever, Polyhedron 1989,8,1649; b) J. M. Arber, B. R.
Dobson, R. R. Eady, S. S. Hasnain, C. D. Garner, T. Matsushita, M.
Nomuras, B. E. Smith, Biochem. J. 1989, 258, 733; c) G. N. George, C. L.
Coyle, B. J. Hales, S. P. Cramer, J. Am. Chem. Soc. 1988, 110, 4057.
[3] D. Szeymies, B. Krebs, G. Henkel, Angew. Chem. 1983, 95, 903; Angew.
Chem. Inr. Ed. Engl. 1983, 2 2 , 8 8 5 ; Angen'. Chem. Suppl. 1983, 1176.
[4] a) J. R. Dorfman, R. H. Holm, Inorg. Chem. 1983,22, 3179; b) R. W Wiggins, J. C. Huffman, G. Christou,J Chem. Soc. Chem. Commun. 1983,1313.
[ S ] W. Schmidt, G. Henkel, B. Krebs, Proc. Inr. Conf: Coord. Chem. 1990,28,
1-9.
161 H. J. Seifert, T. Auel, Z . Anorg. ANg. Chem. 1968, 360, 50.
[7] Crystal structure analyses: Syntex P2, four-circle diffractometer, Mo,. ragraphite monochromator, scintillation counter,
diation (A = 0.71073
140 K, empirical absorption corrections, SHELXTL-PLUS programs, direct methods, least-squares refinement. 2: C,,H,,N,PS3V, M = 720.77, triclinic, space group P1, a = 9.678(3), b = 13.304(5), c = 13.836(5) A,OL =
88.84(3), p = 89.06(3), y = 85.19(3)", V = 1775
Z = 2, p.,,. =
1.349 g ~ m ' ~p(MoKE)
,
= 0.53 mm-', crystal dimensions 0.25 xO.18 x
0.12 mm, 0-28 scan, 28,,, = 48", 5593 independent reflections,
R(R,) = 0.0503 (0.0376) for 3663 observed reflections ( I > 3 a(])), 859 variables (2 blocks), all non-hydrogen atoms anisotropic, H atoms calculated at
idealized positions and fixed, isotropic temperature factors of the H atoms
refined in groups, one scaling factor. 4 : C,,H,,N,PS,V, M = 699.77,
monoclinic, space group P2,, a = 11.252(4), h = 21.345(6), c =
= 94.91(2)", V = 3424 A3, 2 = 4, pcaIC
= 1.358 g ~ m - ~ ,
14.308(15) A,
~(Mo,,) = 0.55 mm-I, crystal dimensions 0.20 x 0.20 x 0.10 mm, w-28
scan, 28,., = 52", 4280 independent reflections, R (R,) = 0.0540 (0.0448)
for 1932 observed reflections ( I > 3 Q)), 412 variables (2 blocks), V, S, and
P atoms anisotropic, N and C atoms isotropic, H atoms calculated at idealized positions and fixed, one common isotropic temperature factor was
M = 572.62, monoclinic,
refined, one scaling factor. 6: C,,H,,N,S,V,
space group P2,/c, a =10.407(4), b =15.663(5), c =16.115(7) A, p =
99.91(3)",
V=2588A3,
Z=4,
pc,,,=1.47Ogcm-',
p(MoK.)=
0.65 mm- ', crystal dimensions 0.30 x 0.25 x 0.20 mm, w-20 scan,
28,,, = 54", 5690 independent reflections, R (R,)= 0.0775 (0.0711) for
226.5 observed reflections ( I > 3a(l)), 363 variables, all non-hydrogen
atoms anisotropic, H atSms calculated at idealized positions and fixed
( U , = 0.04 kZ),
one scaling factor. Further details of the crystal structure
investigation may be obtained from the Fachinformationszentrum
Karlsruhe, Gesellschaft fur wissenschaftlich-technischeInformation mbH,
D-W-7514 Eggenstein-Leopoldshafen 2 (FRG) on quoting the depository
number CSD-56467, the names of the authors, and the journal citation.
A),
A common feature of thiolato complexes with divalent
metal atoms and sterically unemcumbered ligands is the coordination number 4; the central atom often has tetrahedral
or, less frequently, square-planar coordination geometry.
The latter type of coordination is generally limited to complexes with d8 metal
The mononuclear square-planar anions [Cr(SCH,CH,S),]2 - and [Fe(SC,H,S),]' - [51
are exceptions; both have bifunctional 1,2-dithiolato
ligands.
Besides the mononuclear complexes with the general formula [M(SR),]' -,metal thiolates with tetrahedral coordination also include the respective di- and tetranuclear complexes [M,(SR),]'and [M,(SR),,]'-.
In the dinuclear
complexes the MS, tetrahedra are linked by common edges,
in the tetranuclear ones by common vertices. Compounds with other connectivities were previously not
known ; even the only reported trinuclear thiolates with
tetrahedral coordination, [Hg3(SCH2CH,S),]2- L6] and
[Hg3(SCH2C,H,CH,S),I2 -,['I are constructed of either only
edge-, or vertex- and edge-sharing MS, tetrahedra. We report here on a homoleptic thiolatocobalt(I1) complex, the
first compound to contain two MS, tetrahedra which share
a face.
Cobalt(r1) nitrate was treated with sodium propane-2-thiolate in methanol/DMF. After subsequent addition of tetramethylammonium chloride, a black product could be isolated, the analytical data of which was completely consistent
with a complex salt of composition [Me,N],[Co,(SC,H,),,]
and thus with a complex anion which adopts the adamantane-like structure. However, this initial assumption was
soon questioned because of the color which is unusual for
complexes of this type.
According to the results of an X-ray structure analysis,'']
the novel dinuclear compound 1 (Fig. 1 left) was formed
instead under the reaction conditions described above. This
complex anion differs fundamentally from other metal thiolates in the binding arrangement of its ligands.
Crystals of 2 are composed of discrete complex anions 1
(idealized C, symmetry) and Me,N+ cations (idealized Td
/I \
Novel Metal Thiolates: [Co,(SC,H,),I -,
the First Complex with Face-Sharing MS,
Tetrahedra**
By Gerald Henkel,* and Stefan Weissgraber
Transition metal complexes with thiolato ligands are a
well-studied class of compounds. Not only are they important model complexes for the study of biological metal-sulfur centers,"] but they are also suitable starting materials for
the synthesis of mixed sulfido-thiolato clusters.[21
[*I Prof. G. Henkel, Dipl.-Chem. S. Weissgraber
Fachgebiet Anorganische Chemie/Festkorperchemie der Universitat
Lotharstrasse 1, D-W-4100 Duisburg 1 (FRG)
[**I This research was supported by the Deutsche Forschungsgemeinschaft,
the Bundesminister fur Forschung und Technologie, and the Fonds der
Chemischen Industrie.
1368
0 VCH
Verlagsgesellschaft mbH, W-6940 Weinheim, 1992
Fig. 1. Left: Structure of the complex anion 1 in the tetramethylammonium salt
2 (H atoms omitted). Important distances [A] and angles ["I: Co(1)-Co(2)
2.491 (I), Co(1)-S(1) 2.210(2), Co(l)-S(3) 2.343(2), co(l)-S(4) 2.268(2), Co(t)S(5) 2.293(2), C0(2)-S(2) 2.209(2), Co(2)-S(3) 2.346(2), Co(2)-S(4) 2.289(2),
CO(Z)-S(S) 2.303(2); S(l)-Co(l)-S(3) 123.4(1), S(l)-Co(l)-S(4) 128.5(1), S(1)Co(l)-S(S) 115.1(1), S(3)-Co(l)-S(4) 92.9(1), S(3)-Co(l)-S(S) 93,1(1), S(4)Co(1)-S(5) 95.7(1), S(2)-Co(2)-S(3) 123.1(1), S(2)-Co(2)-S(4) 129.6(1), S(2)Co(2)-S(5) 115.5(1), S(3)-Co(2)-S(4) 92.3(1), S(3)-Co(2)-S(S) 92.7(1),
S(4)-Co(2)-S(S) 94.8(1). Right: The metal-centered bitetrahedral Co,S, framework in 1.
0570-0833/92j10f0-1368 $3.50+ ,2510
Angew. Chem. Int. Ed. Engi. 1992, 31, No. f0
symmetry). The separation of the cobalt atoms in the dinuclear complex is remarkably short (2.491(1) A) and results
from the unusual arrangement of the five thiolate S atoms
which occupy the vertices of a trigonal bipyramid and simultaneously also surround the two metal atoms in a tetrahedral
fashion (Fig. 1 right). The cobalt atoms thus occupy the
centers of two sulfur tetrahedra, which have a common face
(S3-S4-S5). The three bridging ligands are positioned so that
the isopropyl groups have a paddlewheel-like arrangement,
that is, they are symmetric with respect to a local threefold
axis. Two different orientations of the complex anion are
found in the crystal which are superimposable by a simple
rotation. One of the orientations appears to be energetically
favored with an occupancy of approximately 64%.
The two CoS, tetrahedra are distorted in a very characteristic manner. The ideal geometry would not only lead to very
small bond angles of about 39" at the bridging sulfur atoms,
but also to an unrealistically short metal-metal distance of
about 1.52 A. The observed structure results from an ideal
tetrahedral arrangement when the bipyramid is stretched
along the apices until the bonding angles at the bridging
atoms approach the mean value of 65.4". At the same time
the Co-Co distance increases to 2.491 8, while the mean
distance between the three sulfur atoms of the bridging ligands decreases to 3.362 A. Consequently, the mean (p-S)Co-(p-S) angle is also quite small (93.58").
The Co-S bonds of the terminal thiolato ligands are not
completely parallel to the Co-Co axis. The slight tilt (8.1 ")
gives rise to three different S-Co-(p-S) angles (mean values
115.3, 123.2, and 129.1 "). The mean lengths of the Co-(p-S)
and Co-S bonds, 2.307 and 2.210 A, respectively (average
2.283 A), are somewhat shorter than those in other thiolatocobalt(I1) complexes; this is especially evident in the comparison with the dinuclear complex anion [Co,(SC,H,),IZ-,
in which each Co atom is bound to two terminal and two
bridging thiolato ligands. The corresponding values here are
2.355 and 2.270 8, for the syn, and 2.363 and 2.213 8, for the
anti
The example of syn- and ~ ~ ~ ~ - [ C O , ( S C , H ,['I) , ]clearly
~illustrates that in complexes with tetrahedral CoS, units and
monofunctional ligands, the change from edge- to facesharing has a drastic influence on the Co-Co distance. For
the anti isomer, this change results in an increase of 0.554 to
3.045(2) A ( + 22.2%) relative to 1, and for the syn isomer of
0.529 to 3.020(3) 8, (+ 21.2 %).
The situation is somewhat different for complexes that are
strained as a result of specific ligand influences, for example
[CO,(SCH,C,H,CH,S),]~
with edge-sharing CoS, tetrahedra.lgl Here the bifunctional ligands are bound so that the
central Co,(p-S), four-membered ring is significantly folded.
Although the Co-Co distance is thereby reduced to
2.786(1) 8,, this value is still 0.3 8, longer than in the title
compound 1.
These results show that the chemistry of complexes with
thiolato ligands is much more diverse than originally assumed. We suggest that the surprising formation of units
with tetrahedral coordination which have common faces is
controlled by specific electronic properties of the ligands. We
already have the first experimental evidence of the existence
of novel iron thiolates with bitetrahedral Fe,S, centers.
turned black. After the addition of the cobalt solution was complete, the reaction mixture was treated with Me,NCI (0.55 g, 5 mmol) and filtered. Diethyl
ether (25 mL) was added to the filtrate, and the mixture was stored at -26 "C.
In the course of a few days black rectangular prisms formed. Yield: 1.51 g
[nm]
(2.66 mmol, 53.2%). Correct C,H,N analysis. UVjVIS (MeCN): I.,,
( E ) = 294 (4500), 332 (4900), 351 (5300), 388 (5600), 538 (500), 598 (500), 778
(300).
Received: June 6, 1992 [Z5392IE]
German version: Angew. Chem. 1992, 104,1382
CAS Registry numbers:
2, 143293-41-8; Co, 7440-48-4.
111 B. Krebs, G. Henkel, Angew. Chem. 1991,103,785; Angew. Chem. Int. Ed.
Engl. 1991, 30, 769, and references therein.
[2] K. S. Hagen, R. H. Holm, Inorg. Chem. 1984, 23, 418, and references
therein.
131 W. Tremel, M. Kriege, B. Krebs, G. Henkel, Inorg. Chem. 1988, 27. 3886,
and references therein.
141 C. Pulla Rao, J. R. Dorfman, R. H. Holm, Inorg. Chem. 1986, 25, 428.
151 D. Sellmann, U. Kleine-Kleffmann, L. Zapf, G. Huttner, L. Zsolnai, J.
Organomet. Chem. 1984,263, 321.
161 G. Henkel, P. Betr, B. Krebs, .
I
Chem. Sac. Chem. Commun. 1985, 1498.
171 G. Henkel, P. Betz, B. Krebs, Inorg. Chim. Acta 1987, 134, 195.
[8] Crystal structure analysis: Siemens P4RA four-circle diffractometer, Mo,,
radiation (A = 0.71073 A), graphite monochromator, rotating anode generator, scintillation counter, 150K, empirical absorption correction,
SHELXTL-PLUS programs, direct methods, least squares refinement;
C,,H,,NS,Co,, M = 567.75, monoclinic, space group PZ,/c, a = 10.755(3),
b = 10.733(3),c = 25.957(5) A, = 101.60(2)", V = 2935 A', 2 = 4, pcaLc
=
1.282 gem-', ~(Mo,,) = 1.47 mm-', transmission range 0.585-0.528,
crystal dimensions 0.32 x 0.27 x 0.24 mm, o scan, 28,,, = 54", 6392 independent reflections, R (R,)= 0.0533 (0.0583) for 4254 observed reflections
(I > 20(I)), 273 variables, all non-hydrogen atoms anisotropic, H atoms
fixed a t idealized positions (r/, = 1.2Uc), one scaling factor, one isotropic
extinction parameter. Further details of the crystal structure investigation
may be obtained from the Fachinformationszentrum Karlsruhe, Gesellschaft fur wissenschaftlich-technischeInformation mbH, D-W-7514 Eggenstein-Leopoldshafen 2 (FRG) on quoting the depository number CSD56492, the names of the authors, and the journal citation.
191 W. Tremel, B. Krebs, G. Henkel, Angew. Chem. 1984,96,604; Angew'. Chrm.
Inl. Ed. Engl. 1984, 23, 634.
On the Mechanism of Coherent Dihydrogen
Tunneling in Transition Metal Trihydrides""
By Hans-Heinrich Limbach,* Gerd Scherer, Marcus Maurer,
and Bruno Chaudret
The solution 'H NMR spectra of transition metal trihydrides (T) exhibit very large temperature-dependent scalar
coupling constants J between the metal-bonded hydrogen
atoms Ha and H, (Fig. l).[' -'I Zilm et aLL51and Weitekamp
et a1.I6I have clearly identified this phenomenon as a mutual
quantum exchange process between the two identical forms
T and T*, characterized by a coherent hydrogen tunneling
frequency that is directly related to the observed exchange
coupling J . At high temperatures the hydrogen atoms are
subject to a classical, that is, stochastic exchange process
which can be characterized by a rate constant k.13]The quantum process was treated in terms of a one-dimensional tunneling model. Since the reaction coordinate had not yet been
[*I
Experimental Procedure
All reactions were conducted in a glovebox under nitrogen.
A solution of Co(N0,),.6H20 (1.46 g, 5 mmol) in methanol (20 mL) was
added dropwise to a stirred solution of sodium isopropanethiolate (1.23 g,
12.5 mmol) in merhanoljDMF (20 mL, 1 : 1) whereby the reaction mixture
Angew. Chem. Int. Ed. Engl. 1992, 31, N o . 10
[**I
Prof. Dr. H.-H. Limbach, Dr. G. Scherer, M. Maurer
Institut fur Organische Chemie der Freien Universitat Berlin
Takustrasse 3, D-W-1000 Berlin 33 (FRG)
Dr. B. Chaudret
Lahoratoire de Chimie de Coordination du CNRS (UP 8241)
205, route de Narbonne, F-31077 Toulouse-Cedex (France)
This work was supported by the Fonds der Chemischen Industrie. We also
thank Prof. K. Zilm, Yale University, New Haven (USA) for helpful discussions of the manuscript.
Q VCH Verla~sgesellschaftmbH, W-6940 Weinheim, 1992
0570-0833j92jtOtO-1369$3.50+.25/0
1369
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