Higher nuclearity Fe,Ru mixed-metal dicarbide cluster compounds derived from ethynediyldiiron complex (η5-C5Me5)(CO)2Fe-C≡C -Fe(η5-C5Me5)(CO)2

Article abstract of DOI:10.1021/om001009c

Reaction of the ethynyliron complexes FP-C≡C-H[FP = Fp (1), Fp* (1*); Fp = (η⁵-C₅H₅)Fe(CO)₂; Fp* = (η⁵-C₅Me₅)Fe(CO)₂] with Ru₃(CO)₁₂ in refluxing benzene affords triruthenium μ-η¹(Ru1):η²(Ru2):η²(Ru3)-acetyl ide cluster type compounds Ru₃(CO)₉ [μ₃-η¹:η²: η²-C≡C-FP] [FP = Fp (3), Fp* (3*)] in a manner similar to the reaction of 1-alkynes. In contrast to the clean reaction of 1 and 1*, reaction of the ethynediyldiiron complex, Fp*-C≡C-Fp* (2*), gives a complicated mixture of products, from which Cp*₂Fe₂Ru₂(μ₄-C₂ )(CO)₁₀ (5*) and Cp*₂Fe₂Ru₆(μ₆-C₂ )(CO)₁₇ (6*) are isolated and characterized as permetalated ethene and permetalated ethane, respectively, by X-ray crystallography. It is revealed that the permetalated hydrocarbon structures in 5* and 6* are constructed via formal addition of a dimetallic species to the C-C triple bond in 2*. The octanuclear complexes 6* and 6 (Cp derivative) are also prepared by thermal dimerization of the tetranuclear FeRu₃(μ-C₂) core in 3* and 3. Higher nuclearity cluster compounds including the heptanuclear dicarbide cluster compound CpFeRu₆(μ₅-C₂) (μ₅-C₂H)(CO)₁₆ (12) and the heptanuclear bis(dicarbide) cluster compound Cp₂Fe₂Ru₅ (μ₅-C₂)₂(CO)₁₇ (15) are obtained not only by thermolysis but also by one-electron oxidation of the deprotonated anionic form of 3 (13).

Full text of DOI:10.1021/om001009c

Organometallics 2001, 20, 1555-1568
1555
High er Nu clea r ity F e,Ru Mixed -Meta l Dica r bid e Clu ster
Com p ou n d s Der ived fr om Eth yn ed iyld iir on Com p lex
(η5-C5Me5)(CO)2F e-CtC-F e(η5-C5Me5)(CO)2
Munetaka Akita,* Shuichiro Sugimoto, Hideki Hirakawa, Shin-ichi Kato,
Masako Terada, Masako Tanaka, and Yoshihiko Moro-oka
Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta,
Midori-ku, Yokohama 226-8503, J apan
Received November 27, 2000
Reaction of the ethynyliron complexes FP-CtC-H [FP ) Fp (1), Fp* (1*); Fp ) (η5-C5H5)-
Fe(CO)2; Fp* ) (η5-C5Me5)Fe(CO)2] with Ru3(CO)12 in refluxing benzene affords triruthenium
µ-η1(Ru1):η2(Ru2):η2(Ru3)-acetylide cluster type compounds Ru3(CO)9[µ3-η1:η2:η2-CtC-FP]
[FP ) Fp (3), Fp* (3*)] in a manner similar to the reaction of 1-alkynes. In contrast to the
clean reaction of 1 and 1*, reaction of the ethynediyldiiron complex, Fp*-CtC-Fp* (2*),
gives a complicated mixture of products, from which Cp*2Fe2Ru2(µ4-C2)(CO)10 (5*) and Cp*2-
Fe2Ru6(µ6-C2)(CO)17 (6*) are isolated and characterized as permetalated ethene and permeta-
lated ethane, respectively, by X-ray crystallography. It is revealed that the permetalated
hydrocarbon structures in 5* and 6* are constructed via formal addition of a dimetallic species
to the C-C triple bond in 2*. The octanuclear complexes 6* and 6 (Cp derivative) are also
prepared by thermal dimerization of the tetranuclear FeRu3(µ-C2) core in 3* and 3. Higher
nuclearity cluster compounds including the heptanuclear dicarbide cluster compound
CpFeRu6(µ5-C2)(µ5-C2H)(CO)16 (12) and the heptanuclear bis(dicarbide) cluster compound
Cp2Fe2Ru5(µ5-C2)2(CO)17 (15) are obtained not only by thermolysis but also by one-electron
oxidation of the deprotonated anionic form of 3 (13).
In tr od u ction
contain acetylide substituents, which may not be always
suitable as surface species (e.g., ester). In this regard,
ethynyl (M-CtC-H) and ethynediyl complexes (M-
CtC-M)4 containing the substituents of the simple
composition are expected to display structural and
reaction features closer to those of the actual surface-
bound species. A polynuclear complex with the C2 ligand
can be recognized as a dicarbide cluster compound,
which is a member of transition metal complexes asso-
ciated with carbon allotropes (Cx) including monocarbon
species and fullurenes.5,6 We have been carrying out a
synthetic study of polynuclear C27 complexes derived
from the ethynyl [FP-CtC-H: FP ) Fp (1), Fp* (1*);
Fp ) (η5-C5H5)Fe(CO)2; Fp* ) (η5-C5Me5)Fe(CO)2] and
ethynediyl iron complexes [Fp*-CtC-Fp* (2*)] (Scheme
The CtC functional group can bind metal centers
together to form polynuclear compounds. In particular,
transition metal acetylide complexes turn out to be
versatile starting compounds for cluster compounds
because the metal center originally σ-bonded to the
acetylide ligand may take part in bond formation with
the added metal species to form a three-dimensional
metal framework.1 The resulting structures have been
recognized as models for surface-bound hydrocarbyl
species,2 which occur during conversions of syngas and
hydrocarbon effected by heterogeneous catalysts.3 Previ-
ous studies have revealed a variety of coordination
modes of acetylide cluster compounds, but many of them
(1) (a) Sappa, E.; Tiripicchio, A.; Braunstein, P. Chem. Rev. 1983,
83, 203. (b) Sappa, E.; Tiripicchio, A.; Carty, A. J .; Toogood, G. E. Prog.
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(b) Heidrich, J .; Steimann, M.; Appel, M.; Beck, W.; Phillips, J . R.;
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tonis, G. A.; Selegue, J . P. J . Am. Chem. Soc. 1991, 113, 2316. (e) St.
Clair, M.; Schaefer, W. P.; Bercaw, J . E. Organometallics 1991, 10,
525. (f) Lemke, F. R.; Szalda, D. J .; Bullock, R. M. J . Am. Chem. Soc.
1991, 113, 8466. (g) Chan, M. C.; Tsai, Y. J .; Chen, C. T.; Lin, Y. C.;
Tseng, T. W.; Lee, G. H.; Wang, Y. Organometallics 1991, 10, 378. (h)
Yang, Y.-L.; Wang, L. J .-J .; Huang, S.-L.; Chen, M.-C.; Lee, G.-H.;
Wang, Y. Organometallics 1997, 16, 1573. See also reference cited in
refs 8a and 8k.
(5) (a) Allegra, G.; Peronaci, E. M.; Ercoli, R. J . Chem. Soc., Chem.
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Organometallics 1992, 11, 1859. (d) J ensen, M. P.; Sabat, M.; Shriver,
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Inorg. Chem. 1984, 23, 2073. (f) Bruce, M. I. Coord. Chem. Rev. 1997,
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Bruce, M. I.; Skelton, B. W.; White, A. H. J . Chem. Soc., Chem.
Commun. 1992, 26. (i) See references cited in refs 5g and 5h.
(3) (a) Somorjai. G. A. Introduction to Surface Science Chemistry
and Catalysis; Wiley-Interscience: New York, 1994. (b) Ertl, G.;
Kno¨zinger, H.; Weitkamp, J . Handbook of Heterogeneous Catalysis;
VCH: Weinheim, 1997.
10.1021/om001009c CCC: $20.00 © 2001 American Chemical Society
Publication on Web 03/17/2001

1556 Organometallics, Vol. 20, No. 8, 2001
Akita et al.
Sch em e 1
1),7,8b,k and have reported various novel aspects of these
systems including H shift on the C2 bridge, conversion
to C2Hx species, and reversible M-M bond scission.8
Herein we disclose details of the results of interaction
of the C2 iron complexes (1, 1*, and 2*)7 with Ru3(CO)12,
leading to higher nuclearity Fe,Ru mixed-metal dicar-
bide cluster compounds. Preliminary reports already
appeared,8c,h and studies on the molecular orbital analy-
sis of polynuclear C2 complexes including the compounds
presented herein and related compounds were reported
recently by Halet et al.9
Reaction of alkynes with Ru3(CO)12 has long been
studied extensively (Scheme 1). Previous studies reveal
that reaction with 1-alkynes produces the triruthenium
acetylide cluster compounds in a selective manner via
C-H bond oxidative addition, whereas internal alkynes
afford various products depending on the structure of
the alkyne substituents and the reaction conditions.10
F igu r e 1. Molecular structure of 3 drawn (with displace-
ment ellipsoid amplitudes) at the 30% probability level.
Labels without atom names are for CO ligands.
Lea d in g to Acetylid e Clu ster Typ e Tetr a n u clea r
Dica r bid e Clu ster Com p ou n d s (µ3-C≡C-F P )(µ-H)-
Ru 3(CO)9 [F P ) F p (3), F p * (3*)]. Treatment of the
ethynyl complexes 1 and 1* with Ru3(CO)12 in refluxing
benzene gave yellow-orange crystals 3 and 3*, respec-
tively, as sole organometallic products (eq 1). The simple
Resu lts a n d Discu ssion
In t er a ct ion of E t h yn ylir on Com p lexes F P -
C≡C-H [F P ) F p (1), F p * (1*)] w it h R u 3(CO)12
,
(6) (a) Beck, W.; Niemer, B.; Wieser, M. Angew. Chem., Int. Ed. Engl.
1993, 32, 923. (b) Lang, H. Angew. Chem., Int. Ed. Engl. 1994, 33,
547. (c) Bunz, U. H. F. Angew. Chem., Int. Ed. Engl. 1996, 35, 969. (d)
Altman, M.; Bunz, U. H. F. Angew. Chem., Int. Ed. Engl. 1995, 34,
569. (e) Bruce, M. I. Chem. Rev. 1998, 98, 2797. (f) Balch, A. L.;
Olmstead, M. M. Chem. Rev. 1998, 98, 2133. (g) Paul, F.; Meyer, W.
E.; Toupet, L.; J iao, H.; Gladysz, J . A.; Lapinte, C. J . Am. Chem. Soc.
2000, 122, 9405. (h) Dembinski, R.; Bartik, T.; Bartik, B.; J aeger, M.;
Gladysz, J . A. J . Am. Chem. Soc. 2000, 122, 810.
(7) The term “C2” stands for two carbon systems including C2 and
C2H species. All Cp* complexes are indicated by asterisks in their
compound numbers. Fp: (η5-C5H5)Fe(CO)2. Fp*: (η5-C5Me5)Fe(CO)2.
Cp: η5-C5H5. Cp*: η5-C5Me5. Ru: Ru(CO)3. Ru : Ru(CO)2.
(8) C2 complexes: (a) Akita, M.; Moro-oka, Y. Bull. Chem. Soc. J pn.
1995, 68, 420. (b) Akita, M.; Oyama, S.; Terada, M.; Moro-oka, Y.
Organometallics 1990, 9, 816. (c) Akita, M.; Sugimoto, S.; Tanaka, M.;
Moro-oka, Y. J . Am. Chem. Soc. 1992, 114, 7581. (d) Akita, M.; Ishii,
N.; Takabuchi, A.; Tanaka, M.; Moro-oka, Y. Organometallics 1994,
13, 258. (e) Akita, M.; Takabuchi, A.; Terada, M.; Ishii, N.; Tanaka,
M.; Moro-oka, Y. Organometallics 1994, 13, 2516. (f) Akita, M.; Terada,
M.; Ishii, N.; Hirakawa, H.; Moro-oka, Y. J . Organomet. Chem. 1994,
473, 175. (g) Akita, M.; Hirakawa, H.; Moro-oka, Y. Organometallics
1995, 14, 2775. (h) Akita, M.; Hirakawa, H.; Tanaka, M.; Moro-oka,
Y. J . Organomet. Chem. 1995, 485, C14. C1 complexes: (i) Takahashi,
Y.; Akita, M.; Moro-oka, Y. J . Chem. Soc., Chem. Commun. 1997, 1557.
Allenylidene complexes: (j) Akita, M.; Kato, S.-I.; Terada, M.; Masaki,
Y.; Tanaka, M.; Moro-oka, Y. Organometallics 1997, 16, 2392. Cn
complexes (n g 4): (k) Akita, M.; Chung, M.-C.; Sakurai, A.; Sugimoto,
S.; Terada, M.; Tanaka, M.; Moro-oka, Y. Organometallics 1997, 16,
4882. (l) Akita, M.; Chung, M.-C.; Terada, M.; Miyauti, M.; Tanaka,
M.; Moro-oka, Y. J . Organomet. Chem. 1998, 565, 49. (m) Akita, M.;
Sakurai, A.; Moro-oka, Y. J . Chem. Soc., Chem. Commun. 1999, 101.
(n) Sakurai, A.; Akita, M.; Moro-oka, Y. Organometallics 1999, 18,
3241. (o) Chung, M.-C.; Sakurai, A.; Akita, M.; Moro-oka, Y. Organo-
metallics 1999, 18, 4684. (p) Akita, M.; Chung, M.-C.; Sakurai, A.;
Moro-oka, Y. J . Chem. Soc., Chem. Commun. 2000, 1285.
1H NMR spectra containing the characteristic shielded
hydride signals [δH -20.05 (3), -19.56 (3*)] in addition
to the η5-C5R5 resonances [δH 3.90 (3), 1.25 (3*)]
indicated formation of the acetylide cluster type prod-
ucts analogous to the reaction product of 1-alkyne
(Scheme 1).
The cluster compound 3 was characterized by X-ray
crystallography, and the molecular structure and se-
lected structural parameters are shown in Figure 1 and
Table 1, respectively. Because no bonding interaction
is present between the distal Fe center and the Ru3
triangle, the Fp group simply works as an acetylide
substituent. In other words, 3 is better described as a
triruthenium µ-η1(Ru1):η2(Ru2):η2(Ru3)-acetylide clus-
ter compound with the Fp-CtC acetylide ligand rather
than as a tetranuclear µ-η1(Fe):η1(Ru1):η2(Ru2):η2(Ru3)-
dicarbide cluster compound. The core structure of 3 is
very similar to that in the previously reported organic
(9) (a) Frapper, G.; Halet, J .-F.; Bruce, M. I. Organometallics 1995,
14, 5044. (b) Frapper, G.; Halet, J .-F.; Bruce, M. I. Organometallics
1997, 16, 2590.
(10) (a) Comprehensive Organometallic Chemistry; Wilkinson, G.,
Abel, E. W., Stone, F. G. A., Eds.; Pergamon: Oxford, 1982; Vol. 4,
Chapter 32.5. (b) Comprehensive Organometallic Chemistry II; Abel,
E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon: Oxford, 1995;
Vol. 7, Chapter 13.

Mixed-Metal Dicarbide Cluster Compounds
Organometallics, Vol. 20, No. 8, 2001 1557
Ta ble 1. Com p a r ison of Str u ctu r a l P a r a m eter s for Acetylid e Clu ster Typ e Com p ou n d s
3
10*
13
4a
14b
16c
M1, M2 ) Ru, Ru M1, M2 ) Fe, Ru M1, M2 ) Ru, Ru
M1, M2 ) Ru, Ru
M1, M2 ) Ru, Ru
M1, M2 ) Fe, Fe
M3, M4 ) Ru, Fe M3, M4 ) Ru, Fe M3, M4 ) Ru, Fe M3, M4 ) Ru, But M3, M4 ) Ru, But M3, M4 ) Fe, Fe
X ) H
X ) H
X ) none
X ) H
none
none
Bond Lengths (Å)
1.271(9)
1.984(8)
2.347(7)
2.349(7)
1.984(8)
2.189(7)
2.199(7)
2.7891(9)
2.793(1)
2.6886(9)
1.87-1.90(1)
1.861-1.890(9)
1.86-1.88 (1)
1.744-1.768(9)
C1-C2
C1-M4
C1-M2
C1-M3
C2-M1
C2-M2
C2-M3
M1-M2
M1-M3
M2-M3
M1-CO
M2-CO
M3-CO
M4-CO
1.33(2)
1.90(1)
2.41(1)
2.40(1)
2.01(1)
2.22(1)
2.20(1)
2.781(2)
2.774(2)
2.819(2)
1.89-1.94(2)
1.96-2.00(2)
1.90(2)
1.32(1)
1.947(9)
2.395(8)
2.377(8)
1.834(9)
2.203(8)
2.169(8)
2.707(2)
2.699(1)
2.791(1)
1.80-1.86(1)
1.92-1.94(1)
1.93-1.96(1)
1.76-1.78(1)
1.315(3)
1.500(3)
2.268(3)
2.271(3)
1.947(3)
2.207(3)
2.214(3)
2.795(3)
2.799(3)
2.792(3)
1.898-1.931(4)
1.910-1.938(4)
1.910-1.944(4)
1.27(3)
1.54(3)
2.24(2)
2.24(2)
1.95(2)
2.18(2)
2.16(2)
2.800(3)
2.790(3)
2.665(3)
1.90-1.92(2)
1.88-1.89(2)
1.85-1.92(2)
1.288(5)
1.959(3)
2.190(3)
2.212(3)
1.839(3)
2.020(3)
2.021(3)
2.6207(7)
2.6252(8)
2.5048(8)
1.765-1.784(4)
1.762-1.784(4)
1.772-1.780(4)
1.768-1.772(4)
1.80(2)
Bond Angles (deg)
149.3(6)
67.0(4)
67.4(5)
69.9(2)
136.0(3)
133.1(4)
160.1(6)
75.6(2)
80.7(5)
80.4(5)
83.8(3)
83.7(3)
57.58(2)
61.29(2)
61.13(2)
C2-C1-M4
C2-C1-M2
C2-C1-M3
M2-C1-M3
M4-C1-M2
M4-C1-M3
C1-C2-M1
M2-C2-M3
C1-C2-M2
C1-C2-M3
M1-C2-M2
M1-C2-M3
M2-M1-M3
M1-M2-M3
M1-M3-M2
M1-C-O
149(1)
65.5(7)
65.3(8)
71.7(4)
135.3(7)
135.9(7)
159(1)
79.2(4)
81.6(8)
81.6(8)
82.2(4)
82.3(4)
61.00(4)
59.38(4)
59.62(4)
173-177(2)
176-177(2)
176-180(1)
178(2)
147.7(7)
65.5(5)
64.6(5)
141.0(2)
70.4(1)
70.6(1)
141(2)
76(1)
77(1)
147.3(3)
d
d
d
d
d
161.6(3)
d
d
d
d
d
57.04(2)
61.57(2)
61.39(2)
178.3-179.4(4)
176.6-178.3(3)
176.4-177.5(4)
172.9-178.0(4)
71.6(2)
75.9(1)
73(1)
138.9(4)
134.2(4)
161.4(7)
79.3(3)
81.5(5)
82.0(5)
135.2(2)
135.0(2)
153.7(2)
78.3(1)
75.5(1)
75.3(1)
84.3(1)
84.3(1)
59.9(1)
60.1(1)
134(1)
138(1)
156(1)
76(1)
76(1)
77(1)
83.7(3)
84.3(3)
85(1)
85(1)
62.16(4)
58.77(3)
59.07(4)
178-180(1)
174-179(2)
176-179(1)
176(1)
56.9(1)
61.3(1)
61.7(1)
174-177(2)
175-178(2)
175-178(2)
60.0(1)
176.9-179.7(8)
176.2-177.2(8)
177-178(1)
175.5-177.9(8)
176.9-178.3(1)
176.0-179.0(1)
175.0-179.9(3)
M2-C-O
M3-C-O
M4-C-O
a
b
Ru3(µ3-CtC-But)(µ-H)(CO)9, neutron diffraction, ref 11. (AsPh4)[Ru3(µ3-CtC-But)(CO)9], ref 21. c A tetrairon analogue of 13,
d
(PPN)[Fe3(µ3-CtC-Fp)(CO)9], ref 5d. Not reported.
acetylide cluster compound (µ3-CtC-But)(µ-H)Ru3(CO)9
(4) [R ) But (Scheme 1); Table 1].11 Upon coordination,
the C-C distance [1.33(2) Å] is slightly elongated
compared to that of the starting compound [1*: 1.173-
(4) Å].8k The Fe-C1 [1.90(1) Å] and Ru1-C2 distances
[2.01(1) Å] fall in the range of single bond lengths, and
the similar distances between the other two Ru centers
and the acetylide carbon atoms [Ru2-C1 2.41(1) Å,
Ru3-C1 2.40(1) Å; Ru2-C2 2.22(1) Å, Ru3-C2 2.20(1)
Å] typical for π coordination indicate symmetrical
coordination of the C2-C1-Fe linkage with respect to
the Ru3 triangle. Although the hydride atom cannot be
located, it should be on the Ru2-Ru3 bond, the distance
[2.819(2) Å] of which is slightly longer than the other
two Ru-Ru distances [2.774(2) and 2.781(2) Å]. In
accord with the structure, the C2 signals [δC 79.7, 174.1
(3); δC 96.8, 168.1 (3*)] appear in the range analogous
to that for trinuclear acetylide cluster compounds of (µ3-
CtC-R)M3 type,1 and the deshielded signals are as-
signed to C2. Details of the structural aspects will be
discussed later as compared with related compounds.
In ter a ction of Eth yn ed iyl Com p lex F p *-C≡C-
F p * (2*) w ith Ru 3(CO)12. Sequ en tia l F or m a tion of
P er m eta la ted Eth en e (5*) a n d Eth a n e Typ e Clu s-
ter Com p ou n d s (6*). In contrast to the clean reaction
of 1 and 1*, reaction of 2* gave a complicated mixture
of products in a manner similar to the reaction of
internal alkynes (Scheme 1).10 In addition to the two
known compounds (3* and Fp*2), two new compounds
5* and 6* showing only one Cp* resonance (1H NMR)
were isolated from the reaction mixture and character-
ized as permetalated ethene and permetalated ethane,
respectively, by X-ray crystallography (Scheme 2). Mo-
lecular structures of 5* and 6* together with expanded
views of the core parts are shown in Figures 2 and 3,
and selected structural parameters are listed in Tables
2 and 3.
Complex 5* is found to be a tetranuclear Fe2Ru2
complex containing one C2 ligand and has a C2-sym-
metrical structure with respect to the axis passing
(11) Sappa, E.; Gambino, O.; Milone, L.; Cetini, G. J . Organomet.
Chem. 1972, 39, 169.

1558 Organometallics, Vol. 20, No. 8, 2001
Akita et al.
Sch em e 2
although the rather short carbon-carbon double bond
should be a result of less effective back-donation due to
the distorted structure as discussed above. A formal
addition reaction of a diruthenium species to the CtC
bond in the ethynediyl complex 2* should lead to the
coordinatively saturated permetalated ethene structure
5* with 66 cluster valence electrons (CVE) (Scheme 3).
Recently Kousantonis et al. reported the syntheses
of the (η5-C5H4R)Ru analogues of 5*, [(η5-C5H4R)Ru]2-
Ru2(µ4-C2)(CO)10 (7) [R ) H (cis-7a ), Me (trans-7b)], via
addition of a mononuclear species, Ru(ethene)(CO)4, to
the µ-ethynediyldiruthenium complexes (η5-C5H4R)(CO)2-
14
Ru-CtC-Ru(η5-C5H4R)(CO)2 (cis and trans refer to
configuration of the two η5-C5H4R rings with respect to
the Ru4(µ4-C2) moiety). The features for the M4(µ4-C2)
cores [C-C: 1.258(5) (cis-7a ), 1.252(4), 1.258(4) Å
(trans-7b with two independent molecules); δC 154.9
(cis-7a ), 157.1 (trans-7b)] are essentially the same as
those of 5*, and the twisting of the M4(µ4-C2) core is
correlated to the configuration of the cyclopentadienyl
rings. The Ru4C2 core in cis-7a is more closely planar
compared to those in trans-7b. The authors proposed
that the permetalated ethene structure was formed via
sequential addition of a mononuclear species, Ru(CO)n,
because the reaction afforded both cis and trans isomers,
which were not interconverted with each other.
The second product 6* (Figure 3) has been character-
ized as an octanuclear compound containing the two C2
units. The metal array is based on the central Ru4
square (Ru1-Ru2-Ru3-Ru4), each edge of which is
bridged by either the Fe or Ru atom, and the bridging
metal atoms are located alternately above and below
the Ru4 square. The C2 ligand bridges the Fe and Ru
centers projected to the same side to interact with the
boat-shaped FeRu5 metal framework. The two C2 rods
above and below the Ru4 plane are arranged perpen-
dicular to each other, as can be seen from a top view of
the core part (Figure 3c).
When the bonding interaction of the C2 bridge is
inspected in detail, the C-C distances [C1-C2, 1.334-
(8) Å; C3-C4, 1.354(7) Å] are further longer than the
C-C distances in 5* and 2# but are found to be
comparable to C(sp)-C(sp) single bond lengths [cf.
butadiyne: 1.384(2) Å].13,15 The distances from the C2
carbon atoms to the out-of-plane metals (Fe1, Fe2,
Ru5, Ru6) [C1-Fe1, 1.908(6) Å; C2-Ru5, 1.997(6) Å;
C3-Fe2, 1.866(5) Å; C4-Ru6, 1.993(5) Å] are in the
ranges of typical σ bond lengths, and the slightly longer
C2-Ru1-4 distances [2.123-2.205(6) Å] indicate con-
tribution of π-bonding interactions between the C2
ligand and the Ru4 square. Although connection of two
corners of the two metal triangles by two metal-metal
bonds forms the distorted boat-shaped core structure,
the C2-metal bonds are basically σ bonds, and there-
fore, the C2M6 moieties can be described as a permeta-
lated ethane. The bis(dicarbide) cluster compound 6* is
found to be coordinatively saturated judging from the
number of its cluster valence electrons (124 e).
through the midpoints of the C-C and Ru-Ru bonds.
The four metal atoms are linked by metal-metal bonds
to form an open-rectangular array, which is slightly
twisted as can be seen from a top view of the core
structure (Figure 3c; Fe-Ru-Ru*-Fe* dihedral angle
is 24°). The C2 ligand interacts with the metal array
through σ bonds [Fe-C1, 1.946(7) Å; Ru-C1, 2.204(7)],
although the Ru-C1 distance is in the upper limit of
Ru-C σ bond lengths and comparable to π bond lengths
[cf. σ bond, 2.026(7) and 2.033(7) Å for Cp2Ru2(µ-
CdCH2)(CO)3;12 π bond, see, for example, the Ru2,3-
C12 lengths (2.2-2.4 Å) for 3 (Table 1)]. The C1-C1*
distance [1.24(1) Å] is longer than the CtC distance of
the ethynediyl complex 2# [η5-C5Me4Et derivative of 2*
(with two independent molecules): 1.206(6), 1.211(6)
Å]8k but substantially shorter than normal C(sp2)d
C(sp2) lengths (1.34 Å).13 The C-C linkage, which spans
the two iron atoms at both the ends of the open-
rectangular array, causes distortion of the Fe2Ru2(µ4-
C2) moiety as judged by the slightly elongated Ru1-
Ru1* distance [2.963(2) Å; cf. Ru-Ru lengths (∼2.8 Å)
in Table 1] and the twisting of the Fe2Ru2 array. The
two Cp* rings are located in trans configuration with
respect to the Fe2Ru2(µ4-C2) moiety to avoid steric
repulsion between them. NMR data suggesting a sym-
metrical structure are consistent with the C2-sym-
metrical X-ray structure. The C2 signal at δC 177.2,
assigned by comparison with a sample obtained from
13CO-enriched Ru3(CO)12, is highly shielded compared
to the R-carbon signals (δC ∼300) of dinuclear µ-vi-
nylidene complexes [M2(µ-CRdCR2)],6d which can be
regarded as a partial structure of 5*. Because the five
carbonyl ligands are observed separately, they do not
exchange at ambient temperature in a solution. Al-
though a number of related complexes including µ-vi-
nylidene complexes6d and alkyne cluster complexes1
have been reported so far, complex 5* is the first
example of a permetalated ethene, (Cp*Fe)2Ru2(µ4-
CdC)(µ-CO)2(CO)8. The EHMO calculation done by
Halet on the CpRu analogue (CpRu)2Ru2(µ4-CdC)(µ-
CO)2(CO)8 clearly indicates that it is a permetalated
ethene in which the filled out-of-plane π-type p orbitals
of the C2 unit play a minor role in the M-C bonding.9a
The p orbitals form a π bond as found in ethene,
(14) (a) Byrne, L. T.; Hos, J . P.; Kousantonis, G. A.; Skelton, B. W.
J . Organomet. Chem. 1999, 592, 95. (b) Byrne, L. T.; Hos, J . P.;
Kousantonis, G. A.; Skelton, B. W.; White, A. H. J . Organomet. Chem.
2000, 598, 28.
(15) (a) Tanimoto, M.; Kuchitsu, K.; Morino, Y. Bull. Chem. Soc.
J pn. 1971, 44, 386. (b) Ho¨lzl, F.; Wrackmayer, B. J . Organomet. Chem.
1979, 179, 394.
(12) Colborn, R. E.; Davies, D. L.; Dyke, A. F.; Endesfelder, A.; Knox,
S. A. R.; Orpen, A. G.; Plaas, D. J . Chem. Soc., Dalton Trans. 1983,
2661.
(13) March, J . Advanced Organic Chemistry, 3rd ed.; J ohn Wiley
and Sons: New York, 1985.

Mixed-Metal Dicarbide Cluster Compounds
Organometallics, Vol. 20, No. 8, 2001 1559
F igu r e 2. Molecular structure of 5* drawn (with displacement ellipsoid amplitudes) at the 30% probability level, where
labels without atom names are for CO ligands: (a) overview; (b) side view of the core part; (c) top view of the core part.
Ta ble 2. Selected Str u ctu r a l P a r a m eter s for 5*
Bond Lengths (Å)
C1-C1*
C1-Fe
C1-Ru
Ru-Ru*
Ru-Fe
Ru-C2
1.24(1)
Ru-C3
Ru-C4
Ru-C5
Fe-C5
Fe-C6
1.885(8)
1.905(9)
2.047(8)
1.932(8)
1.740(8)
1.946(7)
2.204(7)
2.963(2)
2.733(2)
1.933(9)
Bond Angles (deg)
Ru-C1-C1*
Fe-C1-C1*
Ru-C1-Fe
Ru*-Ru-Fe
Ru*-Ru-C1
Ru*-Ru-C2
Ru*-Ru-C3
Ru*-Ru-C4
Ru*-Ru-C5
Fe-Ru-C1
Fe-Ru-C2
Fe-Ru-C3
Fe-Ru-C4
Fe-Ru-C5
C1-Ru-C2
C1-Ru-C3
C1-Ru-C4
C1-Ru-C5
112.0(2)
165.5(2)
82.1(2)
110.61(4)
66.5(2)
92.7(2)
98.7(3)
85.3(3)
155.5(2)
44.9(2)
93.0(2)
150.5(3)
92.8(3)
44.9(2)
87.5(3)
164.4(3)
96.7(3)
89.4(3)
C2-Ru-C3
C2-Ru-C4
C2-Ru-C5
C3-Ru-C4
C3-Ru-C5
C4-Ru-C5
Ru-Fe-C1
Ru-Fe-C5
Ru-Fe-C6
C1-Fe-C5
C1-Fe-C6
C5-Fe-C6
Ru-C-O
88.5(3)
174.2(3)
90.0(3)
86.5(4)
105.7(4)
94.1(3)
53.0(2)
48.4(2)
95.5(3)
100.9(3)
90.9(4)
88.8(4)
173.9 -
178.5(9)
86.7(3)
134.2(7)
139.0(7)
179.3(8)
Ru-C5-Fe
Ru-C5-O5
Fe-C5-O5
Fe-C6-O6
are, therefore, due to M-CO (seven η1-CO and one
µ-CO). These spectral features can be interpreted in
terms of the mechanism shown in Scheme 4. The
inconsistency between the apparent C2-symmetrical
NMR feature and the X-ray structure with no element
of symmetry can be explained by the fast switching of
the two bridging carbonyl ligands (indicated as B and
B′) attached to RuA (process a). The switching is not
frozen even at -80 °C, and signals for B and B′ are not
detected in the temperature range 25 to -80 °C because
of broadening. The three signals observed at low tem-
peratures (Figure 3c) can be assigned to the CO ligands
(F-H) attached to RuC, which are not observed at 25
°C because of the RuC(CO)3 rotation (process b) occur-
ring at a rate faster than the NMR time scale. Thus,
the seven quaternary signals observed at 25 °C are
due to C1, C2, A, C, D, E, and I, and freezing of the
F igu r e 3. Molecular structure of 6* drawn (with displace-
ment ellipsoid amplitudes) at the 30% probability level,
where labels without atom names are for CO ligands: (a)
overview; (b) overview of the core part; (c) top view of the
core part.
A 13C NMR spectrum of 6* observed at 25 °C (Figure
4a,b) contains one set of Cp* signals and seven quater-
nary carbon signals, suggesting the occurrence of dy-
namic behavior. Below -60 °C, 10 quaternary carbon
signals are observed in addition to the Cp* signals, for
which no apparent change is noted (Figure 4c). First of
all, the C2 signals (δC 203.2, 209.0) are assigned by
comparison with a sample obtained from 13CO-enriched
Ru3(CO)12 (Figure 4d).16 The remaining eight signals
(16) The 13C NMR signals for the C2 ligands of 6* were reported.8c
But careful reexamination of 13C NMR measurements revealed that
they were due to impurities and the signals could not be located at
ambient temperature because of the dynamic processes.

1560 Organometallics, Vol. 20, No. 8, 2001
Ta ble 3. Selected Str u ctu r a l P a r a m eter s for 6*
Akita et al.
Bond Lengths (Å)
1.993(5)
C1-C2
1.334(8)
1.354(7)
1.908(6)
2.205(6)
2.181(6)
2.147(6)
2.142(6)
1.997(6)
1.866(5)
2.202(5)
2.187(6)
2.183(6)
2.123(6)
C4-Ru6
C13-Ru1
C13-Fe1
C14-Fe1
C14-Ru2
C17-Ru3
C17-Fe2
Ru-CO
Fe-C(Cp*)
C13-O13
C14-O14
C17-O17
C-O
2.189(7)
1.879(8)
1.874(7)
2.184(8)
2.373(8)
1.780(8)
1.866-1.968(8)
2.086-2.139(7)
1.16(1)
C3-C4
Ru1-Ru2
Ru1-Ru4
Ru1-Ru6
Ru1-Fe1
Ru2-Ru3
Ru2-Fe1
Ru2-Fe2
Ru3-Ru4
Ru3-Ru5
Ru3-Fe2
Ru4-Ru5
Ru4-Ru6
2.7710(6)
2.8466(7)
2.8286(6)
2.711(1)
2.8383(7)
2.7252(9)
2.8442(9)
2.8501(6)
2.815(1)
C1-Fe1
C1-Ru1
C1-Ru2
C2-Ru3
C2-Ru4
C2-Ru5
C3-Fe2
C3-Ru2
C3-Ru3
C4-Ru1
C4-Ru4
1.17(1)
1.17(1)
1.11-1.16(1)
2.677(1)
2.7513(9)
2.7518(7)
Bond Angles (deg)
108.3(4)
Ru1-C1-Ru2
Ru1-C1-Fe1
Ru1-C1-C2
Ru2-C1-Fe1
Ru2-C1-C2
Fe1-C1-C2
Ru3-C2-Ru4
Ru3-C2-Ru5
Ru3-C2-C1
Ru4-C2-Ru5
Ru4-C2-C1
Ru5-C2-C1
Ru2-C3-Ru3
Ru2-C3-Fe2
Ru2-C3-C4
Ru3-C3-Fe2
Ru3-C3-C4
Fe2-C3-C4
Ru1-C4-Ru4
Ru1-C4-Ru6
78.3(2)
Ru1-C4-C3
Ru5-Ru3-Fe2
Ru1-Ru4-Ru3
Ru1-Ru4-Ru5
Ru1-Ru4-Ru6
Ru3-Ru4-Ru5
Ru3-Ru4-Ru6
Ru5-Ru4-Ru6
Ru3-Ru5-Ru4
Ru1-Ru6-Ru4
Ru1-Fe1-Ru2
Ru2-Fe2-Ru3
Ru1-C13-O13
Fe1-C13-O13
Ru2-C14-O14
Fe1-C14-O14
Ru3-C17-O17
Fe2-C17-O17
Ru-C-O
160.76(3)
91.64(2)
120.63(2)
60.67(2)
60.31(2)
121.62(2)
177.93(2)
61.58(2)
61.32(2)
61.29(2)
61.79(2)
132.3(6)
144.4(6)
132.4(6)
143.5(7)
124.9(7)
156.1(8)
173.2-178.6(7)
82.1(2)
120.6(4)
83.3(2)
120.4(4)
148.5(5)
83.3(2)
85.5(2)
100.5(4)
83.3(2)
99.8(4)
173.5(5)
80.6(2)
88.3(2)
108.8(4)
82.2(2)
122.1(4)
151.5(5)
82.8(2)
85.1(2)
Ru4-C4-Ru6
83.9(2)
98.6(4)
Ru4-C4-C3
Ru6-C4-C3
166.6(4)
87.99(2)
115.53(2)
59.60(2)
58.01(2)
106.11(3)
164.12(3)
93.48(2)
59.11(2)
110.14(2)
105.67(3)
56.20(2)
160.08(3)
86.63(2)
119.78(2)
58.10(2)
104.30(3)
Ru2-Ru1-Ru4
Ru2-Ru1-Ru6
Ru2-Ru1-Fe1
Ru4-Ru1-Ru6
Ru4-Ru1-Fe1
Ru6-Ru1-Fe1
Ru1-Ru2-Ru3
Ru1-Ru2-Fe1
Ru1-Ru2-Fe2
Ru3-Ru2-Fe1
Ru3-Ru2-Fe2
Fe1-Ru2-Fe2
Ru2-Ru3-Ru4
Ru2-Ru3-Ru5
Ru4-Ru3-Ru5
Ru4-Ru3-Fe2
Sch em e 3
F igu r e 4. 13C NMR spectra of 6* observed at 100 MHz:
(a) full spectrum observed at 25 °C; (b) expanded spectrum
of (a); (c) expanded spectrum, observed at -60 °C; (d)
expended spectrum of a 13CO-enriched sample, observed
at -60 °C.
RuC(CO)3 rotation at low temperatures causes the
appearance of 10 signals (C1, C2, A, C, D, E, F, G, H,
and I). The C2 signals are shielded compared to those
of 8b (δC 279.4, 285.7) and 8c (δC 285.9, 293.7), the
chemical shifts of which are typical for µ3-alkylidyne
carbon atoms.17
The first example of a permetalated ethane, Co6(µ6-
C2)(CO)18 (8a ), was isolated from a mixture resulting
from thermolysis of the µ3-bromomethylidyne tricobalt
cluster compound (µ3-BrC)Co3(CO)9, as reported by
Ercoli in 19665a and later structurally characterized by
Penfold.5b The metal framework consists of two sepa-
rated Co3 triangles, which are bridged by the C2 ligand.
Later isoelectronic anionic Fe,Co mixed-metal cluster
compounds [Fe4Co2(µ6-C2)(CO)18]2- (8b) and [Fe3Co3(µ6-
(17) Mann, B. E.; Taylor, B. F. 13C NMR Data for Organometallic
Compounds; Academic Press: London, 1981.

Mixed-Metal Dicarbide Cluster Compounds
Organometallics, Vol. 20, No. 8, 2001 1561
Sch em e 4
Sch em e 5
C2)(CO)18]- (8c) were synthesized via a different route
(metal addition to an Fe4-acetylide cluster type C2
complex) by Shriver.5c A Co6 cluster compound with the
metal framework very similar to the upper half of 6,
Co6(µ6-C2)(µ4-S)(CO)14 (9), was isolated from a reaction
mixture of Co2(CO)8 and CS2 as reported by Stangellini.5e
Their C-C lengths [1.37(1) Å (8a ), 1.362(8) Å (8b), 1.37-
(2) Å (9)] are comparable to that of 6*.
When the reaction of 2* with Ru3(CO)12 was moni-
tored by 1H NMR, the permetalated ethene 5* appeared
first and subsequently the acetylide 3* and the per-
metalated ethane 6* were gradually formed. In addition,
complex 5* was found to be thermally less stable than
3* and 6*. These observations suggest that the per-
metalated ethane 6* may be formed by addition of a
ruthenium species to 5* or thermal dimerization of the
FeRu3(µ-C2) core in 3*. To confirm these possibilities,
reaction of an isolated sample of 5* with Ru3(CO)1 (eq
2) and thermolysis of 3* (eq 3) were examined. As a
We attempted addition of another group 8 metal
carbonyl species, Fe2(CO)9, to 5*.18 The reaction was
sluggish, and after the mixture was refluxed in THF
for 15 h a small amount of acetylide cluster compound
10* was obtained (Scheme 5). Complex 10* showed
spectral features (see Experimental Section) essentially
the same as those of 3* and was characterized as an
Fe-substituted derivative of 3* as revealed by X-ray
crystallography.19 In 10*, the Ru atom σ-bonded to the
C2 ligand in 3* (Ru1) is replaced by the Fe atom (Fe1).
This result suggests that the Ru acetylide cluster
compound 3* is also formed via an analogous addition
reaction of an Ru(CO)n species with 5*.
We also examined the reaction of 5* with a proton, a
small electrophile, which may directly add to the steri-
cally congested C2 moiety (Scheme 5). Addition of
CF3SO3H, HBF4‚OEt2, or CF3COOH to a CH2Cl2 solu-
tion of 5* caused an immediate color change from purple
to red-purple and a shift of CO vibrations toward the
higher energy region, suggesting formation of a cat-
ionic species. 1H NMR spectra of mixtures obtained from
CF3SO3H and HBF4‚OEt2 showed one hydride and two
Cp* signals [δH(CD2Cl2) -8.03 (H), 1.91, 1.90 (Cp*)],
whereas protonation with CF3COOH gave a spectrum
with a similar pattern but with different chemical shift
values [δH(CD2Cl2) -4.13 (H), 1.94, 1.81 (Cp*)]. These
spectral features are consistent with either of the
structures 11* shown in Scheme 5, the side-bound
bridging hydride complex or the species with an agostic
C2‚‚‚H‚‚‚Ru interaction. Complex 11* was unstable, and
attempted isolation resulted in fragmentation of the
5* + Ru3(CO)12 refluxing toluene8 3* (50%) + 6* (20%)
(2)
3* refluxing toluene8 6* (42%)
(3)
result, reaction of 5* with Ru3(CO)12 in refluxing toluene
(eq 2) afforded permetalated ethane 6* in addition to
the acetylide cluster compound 3* (Scheme 3). Further-
more, 5* and 6* were isolated in better yields by
carrying out the reactions in refluxing benzene and
toluene, respectively (eqs 4 and 5; see Experimental
Section). It should be noted that thermolysis of 5* in
2* + Ru3(CO)12 refluxing toluene8 5* (59% isolated yield)
(4)
2* + Ru3(CO)12 refluxing toluene8 6* (26% isolated yield)
(5)
the absence of Ru3(CO)12 afforded an intractable mix-
ture of products in which neither 5* nor 6* was detected.
Furthermore, thermolysis of 3* in refluxing toluene (eq
3) resulted in dimerization of its FeRu3(µ-C2) core to give
the permetalated ethane 6* with the doubled core
composition Fe2Ru6(µ-C4)2 in 42% yield (eq 3). Thus, the
octanuclear permetalated ethane structure 6* turns out
to be a thermodynamic sink in the present reaction
system and can be formed via condensation of lower
nuclearity C2 cluster compounds.
(18) Attempted reactions of 5 with Co2(CO)9, Pt(CH2dCH2)(PPh3)2,
[Rh(CH2dCH2)2(µ-Cl)]2, Cp*Rh(CO)2, (η5-C5H4Me)(CO)2, and Mn2(CO)10
afforded a complicated mixture of products from which no characteriz-
able product could be isolated.
(19) An ORTEP view of 10* is included in Supporting Information.

1562 Organometallics, Vol. 20, No. 8, 2001
Akita et al.
cluster structure to give [Fp*-CO]X as the only isolable
product.
Str u ctu r e Exp a n sion of Acetylid e Clu ster Typ e
Tetr a n u clea r Dica r bid e Clu ster Com p ou n d s w ith
Cp Liga n d (3) via Th er m olysis a n d Oxid a tion . Cp
derivatives of the higher nuclearity dicarbide cluster
compounds would be obtained from the Cp derivative
of the ethynediyl complex 2, but synthesis of 2 has been
unsuccessful until now. Then the thermal condensation
of the FeRu3(µ-C2) core observed for the Cp* cluster
compound 3* (eqs 2 and 3) prompted us to examine
similar coupling reactions of the Cp derivative 3.
(i) Th er m olysis. Thermolysis of 3 in refluxing tolu-
ene followed by silica gel TLC separation afforded two
products 6 and 12 resulting from dimerization of the
FeRu3(µ-C2) core in low yields (eq 6). One was charac-
terized as the dicarbide cluster compound 6 on the basis
of FAB-MS and IR data, which are shown in Figure 5.
The isotopomer distribution of the molecular ion peaks
for 6 is in very good agreement with the calculated one,
and fragment peaks due to loss of up to 17 carbonyl
ligands are observed (Figure 5a). These data support
the composition of 6 to be “Cp2Fe2Ru2(µ-C2)2(CO)17” [cf.
6*: Cp*2Fe2Ru2(µ-C2)2(CO)17]. Furthermore, the pattern
of CO vibrations of 6 (Figure 5b) is very similar to that
of 6* and they were shifted toward higher energy region
because of less electron-donating ability of the Cp
ligands compared to the Cp* ligands in 6*. Although
X-ray crystallographic analysis revealed the presence
of an Fe2Ru6(µ6-C2)2 core similar to that in 6*, the
structure could not be refined because of severe disorder
of a part of the metal components. Combined with the
1H NMR data containing only one singlet Cp signal (δH
4.71), it is concluded that 6 is the Cp derivative of the
bis(dicarbide) cluster compound 6*.
F igu r e 5. FAB-MS and IR spectra for 6: (a) FAB-MS
spectrum ([M+ - nCO] region, n ) 0-2) and a spectrum
calculated for M+; (b) comparison of IR spectra of 6 and 6*
(νCO region).
1.334(9) Å] interacts with the FeRu(1,2,3,6) envelope
in the coordination mode, similar to that observed for
(µ5-C2)Ru5(µ-SMe)2(µ-PPh2)2 [C-C: 1.305(5) Å].5h The
C2H moiety [C3-C4: 1.420(9) Å] can be viewed as a
trimetalated [Ru(1,5,6)] ethene, which is sandwiched
between Fe and Ru(4) through π interactions. We
attempted the determination of the origin of the µ5-C2H
atom by conducting the thermolysis in toluene-d8, but
it was unsuccessful because of H-D exchange of the
bridging hydride in 3 prior to its conversion.
(ii) Oxid a t ion of An ion ic Dica r b id e Clu st er .
Redox condensation is another typical synthetic method
of higher nuclearity cluster compounds together with
the thermolysis discussed above.20 An extended struc-
ture may be formed via coupling of a radical species
generated by one-electron oxidation of the anionic clus-
ter compound 13, which was prepared from 3 following
the procedure reported for an organic counterpart, PPh4-
[Ru3(CO)9(µ-H)(µ3-CtC-But)] 14, obtained from 4.21
The other product 12 showing the deshielded 1H NMR
signal (δ 8.64) was a heptanuclear FeRu6 complex
containing one C2 and one C2H ligand as revealed by
X-ray crystallography (Figure 6 and Table 4). The metal
core (Figure 6b) consists of the flat W-shaped raftlike
Ru5 framework [Ru(1-5)], which is fused with the
FeRu(1,3,6) square. In addition, the Ru(3,4,6) moiety
forms a triangular structure, although the Ru4-Ru6
separation [3.056(1) Å] is substantially longer than the
other Ru-Ru lengths [2.7575(8)-2.9759(9) Å]. Complex
12 is a coordinatively saturated 104 CVE species when
C2H and C2 ligands are regarded as five- and six-
electron donors, respectively. The C2 ligand [C1-C2:
(20) (a) Comprehensive Organometallic Chemistry II; Abel, E. W.,
Stone, F. G. A., Wilkinson, G., Eds.; Pergamon: Oxford, 1995; Vol. 10,
Chapter 3. (b) Shriver, D. F.; Kaesz, H.; Adams, R. D. The Chemistry
of Metal Cluster Complexes; VCH: New York, 1990. (c) Metal Clusters
in Chemistry; Braunstein, P., Oro, L. A., Raithby, P. R., Eds.; Wiley-
VCH: Weinheim, Germany, 1999; Vols. 1-3. (d) Structure expansion
of dicarbide clusters by addition of metal fragments has also been
studied by Bruce et al. Adams, C. J .; Bruce, M. I.; Skelton, B. W.; White,
A. H. J . Chem. Soc., Chem. Commun. 1993, 446 and references therein.

Mixed-Metal Dicarbide Cluster Compounds
Organometallics, Vol. 20, No. 8, 2001 1563
F igu r e 6. Molecular structure of 12 drawn (with displace-
ment ellipsoid amplitudes) at the 30% probability level,
where labels without atom names are for CO ligands: (a)
overview; (b) overview of the core part.
F igu r e 7. Molecular structure of 15 (molecule 1) drawn
(with displacement ellipsoid amplitudes) at the 30% prob-
ability level, where labels without atom names are for CO
ligands: (a) overview; (b) overview of the core part.
Sch em e 6
ally µ5-C),20b and in contrast to the previously reported
acetylide clusters where the CtC part interacts with
the top metal atom, the dicarbide parts in 5* are π-coor-
dinated to the bottom-edge Ru atoms.22 The hepta-
nuclear complex 15 is a coordinatively saturated 112
CVE species with two six-electron-donating C2 ligands.
Thus, the (C2)FeRu3 cores in 3 and 13 are coupled upon
thermolysis and oxidation, respectively, to afford the
higher nuclearity cluster compounds 6, 12, and 15.
Treatment of 13 with 1 equiv of [Cp2Fe]PF6 gave a
mixture of products from which two higher nuclearity
cluster compounds 6 and 15 were isolated and charac-
terized (Scheme 6).
Com p a r ison of Str u ctu r es of th e M3(CO)9(µ-X)-
(µ-C≡C-F P ) Typ e Tetr a n u clea r Acetylid e Clu ster
Com p ou n d s [M ) F e, Ru ; X ) H, An ion ]. Through
the present study several M3(CO)9(µ-X)(µ-CtC-FP)
type tetranuclear acetylide cluster compounds 3, 4, 10*,
and 13 are obtained, and their structural parameters
are compared together with related organic counterparts
(4 and 14) and the tetrairon analogue (16) as shown in
Table 1. Complex 16 was obtained by nucleophilic
replacement of (PPN)2[Fe3(CO)9(µ3-CtC-OAc)] by NaFp
as reported by Shriver.5d The coordination modes of
the M4-C2 parts and the structure of the M3(CO)9
core parts in these complexes are very similar; the
CtC-M4 moiety interacts with M1 and M2,3 through
η1 and η2 modes, respectively. As for the ruthenium
derivatives where M2 and M3 equal Ru, the CtC and
M2-M3 distances could be divided into two groups,
those in neutral and those in anionic cluster compounds.
The CtC distances in the anionic complexes are shorter
One of the products was characterized as the bis-
(dicarbide) cluster compound 6 by comparison of its
spectral features with those of an authentic sample. The
other product 15 characterized by X-ray crystallography
turned out to be a heptanuclear bis(dicarbide) cluster
compound with the arrowhead-shaped Ru5 core of C2
symmetry (Figure 7). A unit cell of 15 contains two
crystallographically independent molecules with es-
sentially the same geometry, one of which sits on a crys-
tallographically imposed site. The FpC2 groups inter-
act with the Ru4 butterfly parts as acetylide ligands,
and the Fe atoms are not incorporated in the central
cluster structure. Complex 15 with no Ru(2)‚‚‚Ru(4)
bonding interaction [3.477(2) Å (molecule 1); 3.472(2)
Å (molecule 2)] belongs to a rare class of arrowhead M5
cluster compounds without an encapsulated atom (usu-
(22) (a) Farrar, D. H.; J ohn, G. R.; J ohnson, B. F. G.; Lewis, J .;
Raithby, P. R.; Rosales, M. J . J . Chem. Soc., Chem. Commun. 1981,
886. (b) Lanfranchi, M.; Tiripicchio, A.; Sappa, E.; MacLaughlin, A.;
Carty, A. J . J . Chem. Soc., Chem. Commun. 1982, 538.
(21) Barner-Thorsen, C.; Hardcastle, K. I.; Rosenberg, E.; Siegel,
J .; Landfredi, A. M. M.; Tiripicchio, A.; Camellini, M. T. Inorg. Chem.
1981, 20, 4306.

1564 Organometallics, Vol. 20, No. 8, 2001
Akita et al.
Ta ble 4. Selected Str u ctu r a l P a r a m eter s for 12
Bond Lengths (Å)
C1-C2
1.334(9)
2.282(7)
2.191(6)
1.877(7)
2.263(7)
1.939(6)
2.180(6)
1.420(9)
2.141(6)
C3-Fe
2.012(7)
Ru1-Ru4
Ru1-Ru5
Ru1-Fe
Ru2-Ru3
Ru3-Ru4
Ru3-Ru6
Ru4-Ru5
Ru4-Ru6
Ru6-Fe
2.8927(8)
C1-Ru1
C1-Ru6
C1-Fe
C3-Ru4
C3-Ru5
C4-Ru4
C4-Ru6
C4-Fe
2.253(6)
1.964(7)
2.317(7)
2.133(7)
2.031(7)
2.844(1)
2.8436(8)
2.7764(9)
2.8075(9)
2.754(1)
2.7864(8)
2.7575(8)
2.9759(9)
2.814(1)
3.056(1)
2.675(1)
C2-Ru1
C2-Ru2
C2-Ru3
C3-C4
Ru1-Ru2
Ru1-Ru2
Ru1-Ru3
C3-Ru1
Bond Angles (deg)
C2-C1- Ru1
C2-C1-Ru6
C2-C1-Fe
72.2(4)
134.9(5)
141.7(5)
116.1(3)
82.3(3)
81.9(2)
73.7(4)
158.1(6)
86.2(4)
84.8(2)
77.3(2)
84.9(3)
125.2(5)
74.4(4)
137.2(5)
70.2(4)
82.3(2)
86.2(2)
83.0(2)
83.4(2)
122.6(3)
149.9(3)
69.5(4)
122.3(5)
80.5(3)
80.6(2)
44.0(2)
49.2(2)
48.4(2)
C3-C4-Fe
68.7(4)
86.7(3)
118.6(3)
79.9(3)
111.6(2)
100.9(1)
154.6(2)
73.8(2)
44.3(2)
46.5(2)
50.5(2)
52.4(2)
51.2(2)
52.7(2)
43.9(2)
107.5(2)
77.1(2)
87.33(3)
59.09(2)
61.48(2)
63.03(2)
82.48(3)
122.37(3)
120.84(3)
88.67(4)
55.2(2)
91.1(3)
91.2(3)
54.2(2)
Ru4-Ru3-Ru6
C3-Ru4-C4
64.30(3)
36.2(2)
47.2(2)
95.7(2)
43.9(2)
70.4(2)
74.3(2)
96.6(2)
75.3(2)
44.2(2)
58.81(2)
58.93(2)
79.22(3)
117.01(2)
61.32(2)
114.31(3)
61.94(2)
49.6(2)
52.7(2)
54.38(2)
91.09(3)
54.8(2)
94.7(2)
81.23(4)
41.1(3)
50.5(2)
82.5(2)
81.7(2)
51.7(2)
Ru4-C4-Ru6
Ru4-C4-Fe
Ru6-C4-Fe
C2-Ru1-C3
C2-Ru1-Ru4
C2-Ru1-Ru5
C2-Ru1-Fe
C3-Ru1-Ru5
C3-Ru1-Fe
C3-Ru1-Ru4
C2-Ru2-Ru1
C2-Ru2-Ru3
C2-Ru3-Ru1
C2-Ru3-Ru2
C2-Ru3-Ru4
C2-Ru3-Ru6
Ru5-Ru1-Fe
Ru1-Ru2-Ru3
Ru1-Ru3-Ru2
Ru1-Ru3-Ru4
Ru1-Ru3-Ru6
Ru2-Ru3-Ru4
Ru2-Ru3-Ru6
Ru1-Fe-Ru6
C1-Fe-Ru1
C1-Fe-C3
C3-Ru4-Ru1
C3-Ru4-Ru3
C3-Ru4-Ru5
C3-Ru4-Ru6
C4-Ru4-Ru1
C4-Ru4-Ru3
C4-Ru4-Ru5
C4-Ru4-Ru6
Ru1-Ru4-Ru3
Ru1-Ru4-Ru5
Ru1-Ru4-Ru6
Ru3-Ru4-Ru5
Ru3-Ru4-Ru6
Ru5-Ru4-Ru6
Ru1-Ru5-Ru4
C3-Ru5-Ru1
C3-Ru5-Ru4
Ru3-Ru6-Ru4
Ru3-Ru6-Fe
C1-Ru6-Ru3
C4-Ru6-Ru3
Ru4-Ru6-Fe
C3 -Fe-C4
Ru1-C1-Ru6
Ru1-C1-Fe
Ru6-C1-Fe
C1-C2-Ru1
C1-C2-Ru2
C1-C2-Ru3
Ru1-C2-Ru2
Ru1-C2-Ru3
Ru2-C2-Ru3
C4-C3- Ru1
C4-C3-Ru4
C4-C3-Ru5
C4-C3-Fe
Ru1-C3-Ru4
Ru1-C3-Ru5
Ru1-C3-Fe
Ru4-C3-Ru5
Ru4-C3-Fe
Ru5-C3-Fe
C3-C4- Ru4
C3-C4-Ru6
C1-Ru6-C4
C1-Ru6-Ru4
C1-Ru6-Fe
C4-Ru6-Ru4
C4-Ru6-Fe
C3-Fe-Ru1
C3-Fe-Ru6
C1-Fe-C4
C1-Fe-Ru6
C4-Fe-Ru1
C4-Fe-Ru6
Sch em e 7
than those in the neutral complexes by ca. 0.05 Å, and
in contrast, the M2-M3 distances in the anionic com-
plexes are longer than those in the neutral complexes
by ca. 0.1 Å. The former feature should be a result of
weakened π donations from the acetylide ligand to the
anionic trimetallic framework, and the latter is due to
lack of the bridging hydride ligand in the anionic
complexes. It is notable that no significant influence of
the metal substituents (M4) on the CtC moiety is
detected when compared with the organic counterparts
4 and 14. Thus, the M4 groups in 3, 4, 10*, 13, and 16
work simply as acetylide substituents and no apparent
communication is present between the M4 group and
the triangular cluster part.
Con clu sion
The cluster transformations described in the present
paper are summarized in Scheme 7. As for the Cp*

Mixed-Metal Dicarbide Cluster Compounds
Organometallics, Vol. 20, No. 8, 2001 1565
Ta ble 5. Selected Str u ctu r a l P a r a m eter s for 15a
molecule 1
molecule 2
Bond Lengths (Å)
1.34(2)
C1-C2
1.32(2)
1.93(2)
2.14(1)
2.14(1)
2.26(1)
2.26(1)
2.16(1)
2.731(2)
2.905(2)
2.900(2)
2.792(2)
C3-C4
C5-C6
1.35(2)
1.89(1)
2.15(1)
2.18(1)
2.26(1)
2.23(1)
2.15(1)
2.709(2)
2.875(2)
2.944(2)
2.784(2)
1.85-1.90(2)
2.05-2.17(2)
1.79(2)
C1-Fe1
C3-Fe2
C3-Ru5
C4-Ru1
C4-Ru2
C4-Ru5
C4-Ru4
Ru1-Ru4
Ru4-Ru5
Ru3-Ru4
1.93(1)
2.14(1)
2.15(1)
2.24(1)
2.23(1)
2.16(1)
2.708(2)
2.885(2)
2.916(2)
C5-Fe11
C1-Ru3
C5-Ru13
C2-Ru1
C6-Ru11
C2-Ru2
C6-Ru12
C2-Ru3
C6-Ru13
C2-Ru4
C6-Ru12*
Ru1-Ru2
Ru2-Ru3
Ru2-Ru5
Ru3-Ru5
terminal Ru-CO
bridging Ru-CO
terminal Fe-CO
Ru11-Ru12
Ru12-Ru13
Ru12-Ru13*
Ru13-Ru13*
terminal Ru-CO
bridging Ru-CO
terminal Fe-CO
1.87-1.91(2)
1.92-2.18(2)
1.70-1.78(2)
Bond Angles (deg)
C2-C1-Fe1
144(1)
78(1)
138.5(8)
146(1)
130(1)
C4-C3-Fe2
C4-C3-Ru5
Fe2-C3-Ru5
C3-C4-Ru1
C3-C4-Ru4
C3-C4-Ru2
C3-C4-Ru5
Ru1-C4-Ru4
Ru1-C4-Ru2
Ru1-C4-Ru5
Ru4-C4-Ru2
Ru4-C4-Ru5
Ru5-C4-Ru2
143(1)
C6-C5-Fe11
145(1)
C2-C1-Ru3
76.1(8)
141.2(7)
145(1)
C6-C5-Ru13
75.3(8)
139.9(8)
144(1)
133(1)
108(1)
Fe1-C1-Ru3
C1-C2-Ru1
Fe11-C5-Ru13
C5-C6-Ru11
C1-C2-Ru4
131(1)
C5-C6-Ru12*
C1-C2-Ru2
109.2(9)
67.7(9)
78.0(4)
76.7(5)
144.8(7)
103.7(6)
82.4(5)
80.0(4)
74.8(5)
70.6(5)
34.7(5)
79.49(5)
96.18(5)
96.44(5)
57.50(4)
61.16(5)
60.67(4)
73.90(4)
176-178(2)
145(1)
107.7(9)
68.2(8)
77.9(4)
76.9(4)
145.1(7)
104.3(5)
82.0(5)
80.7(4)
C5-C6-Ru12
C1-C2-Ru3
C5-C6-Ru13
68.7(8)
77.5(5)
75.2(4)
144.2(6)
103.6(5)
84.4(5)
79.6(4)
74.7(7)
73.4(5)
36.0(5)
79.69(7)
95.65(5)
97.28(5)
57.15(5)
62.68(4)
60.17(4)
73.25(5)
177-179(2)
144(1)
Ru1-C2-Ru4
Ru1-C2-Ru2
Ru1-C2-Ru3
Ru4-C2-Ru2
Ru4-C2-Ru3
Ru2-C2-Ru3
C2-Ru1-C4
Ru12-C6-Ru11
Ru11-C6-Ru12*
Ru11-C6-Ru13
Ru12-C6-Ru12*
Ru12-C6-Ru13
Ru13-C6-Ru12*
C6-Ru11-C6*
C4-Ru2-C2
C1-Ru3-C2
C4-Ru4-C2
C3-Ru5-C4
74.0(5)
35.7(5)
C6-Ru12-C6*
C5-Ru13-C6
Ru4-Ru1-Ru2
Ru1-Ru2-Ru3
Ru1-Ru4-Ru3
Ru5-Ru2-Ru3
Ru5-Ru3-Ru2
Ru5-Ru3-Ru4
Ru4-Ru5-Ru2
terminal M-C-O
Ru2-C1c-O1c
Ru1-C1c-O1c
Ru1-C1c-Ru2
Ru3-C3c-O3c
Ru5-C3c-O3c
Ru5-C3c-Ru3
Ru12-Ru11-Ru12*
Ru11-Ru12-Ru13*
Ru11-Ru12-Ru13
Ru13-Ru12-Ru13*
Ru13*-Ru13-Ru12
Ru13*-Ru13-Ru12*
Ru12-Ru13-Ru12*
terminal M-C-O
Ru12-C11b-O11b
Ru11-C11b-O11b
Ru11-C11b-Ru12
Ru13-C13c-O13c
Ru13-C13c-O13c
Ru13-C13c-Ru13
Ru1-Ru2-Ru5
Ru1-Ru4-Ru5
Ru5-Ru4-Ru3
Ru3-Ru5-Ru2
Ru3-Ru5-Ru4
Ru2-Ru3-Ru4
95.75(4)
96.62(5)
57.54(4)
61.35(5)
61.79(4)
73.36(4)
Ru4-C1d-O1d
Ru1-C1d-O1d
Ru1-C1d-Ru4
146(1)
133(1)
81.0(5)
131(1)
83.3(7)
140(1)
136(1)
83.9(6)
137(1)
79.9(6)
138.9(5)
138.9(5)
82.3(9)
a
With two independent molecules. Molecule 2 sits on a crystallographic C2-symmetrical site.
techniques. THF, ether, hexanes, benzene, toluene (Na-K
alloy), CH2Cl2 (P2O5), and EtOH [Mg(OEt)2] were treated with
appropriate drying agents, distilled, and stored under argon.
1H and 13C NMR spectra were recorded on J EOL GX-270 (1H
NMR, 270 MHz; 13C NMR, 67 MHz) and EX-400 (1H NMR,
400 MHz; 13C NMR, 100 MHz) spectrometers. Solvents for
NMR measurements containing 0.5% TMS were dried over
molecular sieves, degassed, distilled under reduced pressure,
and stored under Ar. IR spectra (KBr pellets) and mass spectra
(FD) were obtained on a J ASCO FT/IR 5300 spectrometer and
a Hitachi M-80 mass spectrometer, respectively. Complexes
system, the present study reveals that permetalated
ethene and ethane structures result from formal se-
quential addition of dimetallic fragments to the CtC
triple bond in the ethynediyl complex, a permetalated
ethyne (Scheme 3). Although the starting compounds
1, 1*, and 2* are acetylide complexes, the structural
features of the obtained permetalated hydrocarbons
characterized by X-ray crystallography are totally dif-
ferent from those of previously reported acetylide cluster
compounds.1 The higher nuclearity cluster compounds
are also formed by thermal and redox condensation of
the FeRu3(µ-C2) core in the acetylide cluster compound
as revealed by the results of the Cp system. The results
obtained would provide insights into the coordination
modes of dicarbide species (C2) on a heterogeneous
catalyst surface.2 The synthetic study on dicarbide (C2)
1,8b 1*,8b 2*,8k Ru3(CO)12,23 Fe2(CO)9,24 and [Cp2Fe]PF6 were
25
prepared according to the published methods. 13CO-enriched
Ru3(CO)12 was prepared by heating a toluene suspension of
Ru3(CO)12 under 13CO (4 atm) for 3 days at 120 °C. Other
chemicals were purchased and used as received. Chromatog-
raphy was performed on alumina.
Rea ction of 1 w ith Ru 3(CO)12. A benzene solution (15 mL)
of 1 (227 mg, 1.10 mmol) and Ru3(CO)12 (651 mg, 1.00 mmol)
was refluxed for 1.5 h. After removal of the volatiles, the
cluster compounds is now extended to polycarbon (C2n
)
cluster compounds derived from related polyynediyl
complexes, M-(CtC)n-M.8k-p
(23) Bruce, M. I.; J ensen, C. M.; J ones, N. L. Inorg. Synth. 1990,
28, 216.
(24) King, R. B. Organomet. Synth. 1965, 1, 93.
(25) Sohn, Y. S.; Hendrickson, D. N.; Gray, H. B. Inorg. Chem. 1971,
10, 1559.
Exp er im en ta l Section
Gen er a l Meth od s. All manipulations were carried out
under an inert atmosphere by using standard Schlenk tube

1566 Organometallics, Vol. 20, No. 8, 2001
Akita et al.
products were extracted with ether and passed through an
alumina plug. Crystallization from ether-hexanes gave 3 (223
mg, 0.29 mmol, 29% yield). 3. 1H NMR (CDCl3): δH -20.05
(1H, s, Ru-H), 3.90 (5H, s, Cp). 13C NMR (CDCl3): δC 79.7 (s,
tC-Fe), 86.7 (d, J ) 177 Hz, Cp), 174.1 (s, Ru-Ct), 190-
194 (br, Ru-CO), 212.6 (s, Fe-CO). IR: 2084, 2036, 1986,
1978, 1963 cm-1. Anal. Calcd for C18H6O11FeRu3: C, 28.55; H,
0.80. Found: C, 28.62; H, 0.83.
reduced pressure followed by silica gel TLC separation gave
6* (30 mg, 0.021 mmol, 42% yield based on consumed 3*) and
3* (recovered, 40 mg, 0.05 mmol), which were characterized
by IR and 1H NMR. Other minor products could not be
characterized.
Rea ction of 3* w ith F e2(CO)9. A THF solution (10 mL) of
3* (96.0 mg, 0.112 mmol) and Fe2(CO)9 (81 mg, 0.22 mmol)
was heated for 15 h at 65 °C. After removal of the volatiles,
separation by column chromatography afforded Fp*2 (6.0 mg,
0.012 mmol), yellow compound 10* (7.2 mg, 0.092 mmol, 8%
yield based on consumed 3*), and 3* (recovered, 35 mg, 0.041
Rea ction of 1* w ith Ru 3(CO)12. A benzene solution (30
mL) of 1* (0.58 g, 2.12 mmol) and Ru3(CO)12 (1.03 g, 1.61 mmol)
was refluxed for 4 h. After removal of the volatiles, the
resulting solid was washed with hexanes (10 mL × 3).
Extraction with CH2Cl2 and filtration through a silica gel pad
followed by crystallization from CH2Cl2-hexanes gave 3* (992
1
mmol). 10*. H NMR (CDCl3): δH -20.1 (1H, s, Ru-H), 1.90
(15H, s, Cp*). 13C NMR (CDCl3): δC 10.1 (q, J ) 128 Hz,
C5Me5), 97.6 (s, C5Me5), 100.0 (s, tC-Fe), 182.8 (s, Ru-Ct),
213.8, 214.7 (s, Fe-CO). IR: 2085, 2057, 2021, 2005, 1992,
1965, 1943 cm-1. Anal. Calcd for C23H16O11Fe2Ru2: C, 35.32;
H, 2.06. Found: C, 35.07; H, 2.06.
1
mg, 1.20 mmol, 75% yield). 3*. H NMR (CDCl3): δH -19.56
(1H, s, Ru-H), 1.25 (15H, s, Cp*). 13C NMR (CDCl3): δC 9.5
(q, J ) 128 Hz, C5Me5), 96.8 (s, tC-Fe), 97.5 (s, C5Me5), 168.1
(s, Ru-Ct), 215.1 (s, Fe-CO). IR: 2078, 2050, 2024, 2005,
1996, 1987, 1962 cm-1. Anal. Calcd for C23H16O11FeRu3: C,
33.39; H, 1.95. Found: C, 33.19; H, 1.80.
P r oton a tion of 5*. (i) With CF 3SO3H or HBF 4‚OEt2. To
a CH2Cl2 solution of 5* cooled in an ice bath was added CF3-
SO3H or HBF4‚OEt2 (2 equiv), and the resulting mixture was
stirred at ambient temperature. IR monitoring indicated a
shift of the µ-CO vibration from 1783 cm-1 (5*) to 1837 cm-1
(11*). Attempted isolation of the product by addition of hexane
Rea ction of 2* w ith Ru 3(CO)12. A benzene solution (40
mL) of 2* (803 mg, 1.69 mmol) and Ru3(CO)12 (803 mg, 1.26
mmol) was refluxed for 9 h. After removal of the volatiles under
reduced pressure, products were extracted with CH2Cl2 and
passed through a Florisil plug. Concentration followed by
cooling at -20 °C gave unreacted Ru3(CO)12 (177 mg). Further
concentration of the filtrate followed by cooling at -20 °C gave
5* (192 mg, 0.22 mmol, 25% yield based on the consumed Ru3-
(CO)12) as dark-purple crystals. Further separation of the
filtrate by alumina column chromatography (eluted with 1:4
CH2Cl2-hexanes) afforded 6* (82 mg, 0.05 mmol, 11% yield)
as black crystals. 5*. 1H NMR (CDCl3): δH 1.55 (30H, s, Cp*).
13C NMR (CDCl3): δC 9.5 (q, J ) 128 Hz, C5Me5), 98.0 (s,
C5Me5), 177.2 (s, µ4-C2), 191.1, 196.4, 205.6 (Ru-CO), 217.8
(Fe-CO), 262.5 (µ-CO). IR: 2082, 2048, 1997, 1981, 1963,
1953, 1775 cm-1. Anal. Calcd for C32H30O10Fe2Ru2: C, 43.26;
1
gave [Fp*-CO]X. 11*. H NMR data are in the text. IR (CH2-
Cl2): 2123, 2102, 2061, 2048, 2029, 1837 cm-1
.
(ii) With CF 3COOH. Reaction was carried out as described
above. 1H NMR data are in the text. IR (CH2Cl2): 2101, 2050,
2026, 1986, 1803 cm-1
.
Th er m olysis of 3. A toluene solution (10 mL) of 3 (119 mg,
0.16 mmol) was refluxed for 3.5 h. After removal of the
volatiles, products were separated by silica gel TLC eluted with
1:2 hexane-CH2Cl2. From the top brown band, black product
12 (23 mg, 0.018 mmol, 28% yield based on consumed 3) was
isolated, and from the next yellow band the starting compound
3 (0.031 mmol) was recovered. A trace amount of permetalated
ethane 6 was isolated from a middle purple-red band. 6. 1H
NMR (CDCl3): δH 4.71 (10H, s, Cp). IR (KBr): 2082, 2063,
2022, 1856 cm-1. FAB-MS: m/z 1373, 1373 - 28n (n ) 1-17).
An analytically pure sample could not be obtained despite
several attempts. 12. 1H NMR (C6D6): δH 8.64 (1H, s, C2H),
5.13 (5H, s, Cp). IR: 2071, 2005, 1962, 1824 cm-1. Anal. Calcd
for C25H6O16FeRu6: C, 24.52; H, 0.49. Found: C, 24.86; H, 0.95.
FD-MS: m/z 1226 (the most intense peak).
1
H, 3.40. Found: C, 43.50; H, 3.66. 6*. H NMR (CD2Cl2): δH
1.61 (30H, s, Cp*). 13C NMR (CD2Cl2 at 25 °C): δC 9.0 (q, J )
128 Hz, C5Me5), 98.7 (s, C5Me5), 190.1, 191.1, 194.2 (CO), 202.9,
208.4 (C2), 210.7 (CO), 243.5 (µ-CO). 13C NMR (CD2Cl2 at -80
°C): δC 9.4 (C5Me5), 98.6 (C5Me5), 190.5, 190.9, 191.4, 194.4,
197.2, 200.8 (CO), 203.2, 209.0 (C2), 210.4 (CO), 244.5 (µ-CO).
IR: 2076, 2057, 2016, 1836 cm-1. Anal. Calcd for C42H32O17
Cl2Fe2Ru6: C, 32.55; H, 2.00. Found: C, 32.78; H, 2.06.
-
P r ep a r a tion of 13. To a THF solution (50 mL) of 3 (475
mmol, 0.628 mmol) was added an EtOH solution of KOH (53
mg, 0.94 mmol/12 mL) followed by an EtOH solution of PPh4-
Br (364 mg, 0.63 mmol/10 mL), while CO bubbling was
maintained. After removal of the volatiles under reduced
pressure, the residue was extracted with CH2Cl2 and passed
through a Celite plug. Addition of ether gave orange solids,
crystallization of which from acetone-ethanol afforded 13 as
orange crystals (193 mg, 0.176 mmol, 28% yield). 13. 1H NMR
(acetone-d6): δH 8.05-7.84 (20H, m, PPh4), 5.15 (5H, s, Cp).
13C NMR (acetone-d6): δC 215.0 (s, Fe-CO), 203.5 (s, Ru-CO),
P r ep a r a tion of 5*. A mixture of 2* (1.01 g, 2.05 mmol)
and Ru3(CO)12 (1.06 g, 2.26 mmol) dissolved in benzene (60
mL) was refluxed for 6 h. After the mixture was left overnight
at -30 °C, the frozen mixture was thawed and the supernatant
solution was removed via a cannula. The residue was extracted
with a CH2Cl2-hexane mixture and passed through a short
alumina column (5 cm). After Ru3(CO)12 and Fp*2 were eluted
with CH2Cl2-hexane, the product was eluted with ether.
Evaporation of the ether solution gave 5* (1.03 g, 1.20 mmol,
59% yield).
P r ep a r a tion of 6*. A toluene solution (60 mL) of 2* (312
mg, 0.60 mmol) and Ru3(CO)12 (372 mg, 0.58 mmol) was
refluxed for 3.5 h. After removal of the volatiles under reduced
pressure, the residue was subjected to alumina column chro-
matography and Ru3(CO)12 and Fp*2 were eluted with CH2-
Cl2-hexane (1:4). A purple-gray band eluted with CH2Cl2-
hexane (1:3-1:2) was collected. Complex 6* (0.12 g, 0.08 mmol,
26% yield) was obtained by evaporation of the solvent.
Rea ction of 5* w ith Ru 3(CO)12. A toluene solution (10 mL)
of 5* (35 mg, 0.05 mmol) and Ru3(CO)12 (32 mg, 0.02 mmol)
was refluxed for 3 h. Removal of the volatiles under reduced
pressure followed by silica gel TLC separation gave 3* (17 mg,
0.02 mmol, 50% yield) and 6* (6 mg, 0.004 mmol, 20% yield),
which were characterized by IR and 1H NMR. Other minor
products could not be characterized.
187.0 (s, Ru-Ct), 136.4 (d, J CP ) 2 Hz, p-Ph), 135.7 (d, J CP
)
10 Hz, m-Ph), 131.4 (d, J CP ) 13 Hz, o-Ph), 119.1 (d, J CP ) 90
Hz, ipso-Ph), 88.2 (s, Cp), 74.3 (s, Fe-t). IR: 2045, 2026, 1993,
1950, 1926 cm-1. Anal. Calcd for C40H25O9PFeRu3: C, 46.21;
H, 2.42. Found: C, 46.42; H, 2.46.
Oxid a tion of 11* w ith [Cp 2F e]P F 6. A CH2Cl2 solution (15
mL) of 11* (294 mg, 0.268 mmol) and [Cp2Fe]PF6 (89 mg, 0.269
mmol) was stirred for 3 h at ambient temperature. After
removal of the volatiles, the residue was subjected to silica
gel TLC separation (eluted with 1:1 ether-hexane). Products
6 and 15 were isolated from brown and dark-red bands,
respectively. Recrystallization gave 6 (43 mg, 0.031 mmol, 23%
yield; from CH2Cl2-hexane) and 15 (23 mg, 0.018 mmol, 13%
yield; from CH2Cl2-ether) as black thin plates and black
crystals, respectively. 15. 1H NMR (CDCl3): δH 4.98 (5H, s,
Cp). IR: 2064, 2018, 1986, 1875 cm-1. Anal. Calcd for
Th er m olysis of 3*. A toluene solution of 3* (78 mg, 0.10
mmol) was refluxed for 11 h. Removal of the volatiles under
C
31H10O17Fe2Ru5: C, 29.28; H, 0.79. Found: C, 29.56; H, 1.06.

Mixed-Metal Dicarbide Cluster Compounds
Organometallics, Vol. 20, No. 8, 2001 1567
Ta ble 6. Cr ysta llogr a p h ic Da ta
complexa
d
3
5*
6*‚CH2Cl2
10*
formula
fw
C
757.3
AFC5S
25
orthorhombic
pbca
15.166(2)
21.445(4)
14.025(2)
18H6O11FeRu3
C32H30O10Fe2Ru2
888.42
AFC5R
25
monoclinic
C2/c
14.124(6)
11.537(5)
20.142(5)
93.23(4)
3277(4)
4
C42H32O17Cl2Fe2Ru6
1597.72
R-AXIS IV
-60
C23H16O11FeRu3
782.2
AFC5R
25
monoclinic
P21/n
17.857(4)
10.156(1)
17.162(3)
116.81(1)
2777(1)
4
diffractometer
temp (°C)
cryst syst
space group
a/Å
monoclinic
C2/c
19.545(5)
20.928(2)
23.886(4)
96.102(4)
9714(2)
8
2.19
25.7
55
10 083
b/Å
c/Å
â/deg
V/Å3
4561(2)
8
2.21
25.9
55
Z
d
calcd/g cm-3
1.80
18.1
50
6177
1.87
21.4
55
6963
µ/cm-1
2θ/deg
no. data
collected
no. data with
I > 3 σ(I)
no. params
refined
5818
2582
298
2668
208
8719e
632
5338
343
Rb
Rw
0.053
0.040
0.059
0.050
0.055f
0.173g
0.053
0.073
c
complexa
12‚CH2Cl2
13
15‚(H2O)2/3
formula
fw
C26H8O16Cl2FeRu6
1309.5
AFC5R
25
monoclinic
P21/c
11.848(5)
10.812(5)
27.739(4)
99.11(2)
3508(4)
4
C42H25O11PFeRu3
1095.7
AFC5R
25
monoclinic
P21/n
10.450(3)
12.997(7)
30.117(10)
99.10(3)
4039(3)
4
C31.67H11.33O17Fe2Ru5
1283.5
AFC5R
25
monoclinic
C2/c
42.215(5)
15.776(5)
16.842(4)
100.06(2)
11044(5)
12
diffractometer
temp (°C)
cryst syst
space group
a/Å
b/Å
c/Å
â/deg
V/Å3
Z
d
calcd/g cm-3
2.48
30.9
55
8880
1.80
15.5
50
7894
2.32
28.4
50
10 261
µ/cm-1
max 2θ/deg
no. data
collected
no. data with
I > 3 σ(I)
no. params
refined
5250
464
4173
523
6260
754
Rb
Rw
0.035
0.039
0.042
0.030
0.052
0.047
c
a
b
2
d
Refined with teXsan26 unless otherwise stated. R ) [∑||Fo| - |Fc||]/∑|Fo|. c Rw ) [∑{w(|Fo| - |Fc|)2}/∑wFo
]
0.5; w ) 1/σ2(Fo2). Refined
with SHELXS97.32b e Number of data with I > 2 σ(I). f R1 ) [∑||Fo| - |Fc||]/∑|Fo| (for data with I > 2 σ(I)). wR2 ) [∑{w(Fo - Fc2)}2/
g
2
∑{w(Fo2)2}]0.5; w ) 1/[σ2(Fo2) + (0.1000P)2] where P ) [2Fc + max(Fo2,0)]/3 (for all data).
2
Exp er im en ta l P r oced u r e for X-r a y Cr ysta llogr a p h y.
(i) F or 3, 5*, 10*, 12, 13, a n d 15. Suitable single crystals were
mounted on glass fibers. Diffraction measurements were made
on Rigaku AFC5S (3) and AFC5R (5*, 10*, 12, 13, and 15)
automated four-circle diffractometers at 25 °C by using
graphite-monochromated Mo KR radiation (λ ) 0.710 69 Å).
The unit cells were determined and refined by a least-squares
method using 20 independent reflections (2θ ≈ 20°). Data were
collected with ω-2θ (3, 5*, 10*) and ω scan techniques (12,
13, 15). If σ(F)/F was more than 0.1, a scan was repeated up
to three times and the results were added to the first scan.
Three standard reflections were monitored every 100 (3) and
150 measurements (the others). The data processing (data
collection) was performed on FACOM A-70 (3) and Microvax
II computers (the others). In the reduction of data, Lorentz
and polarization corrections were made. An empirical absorp-
tion correction (Ψ scan) was made.
a Microvax II computer by using the teXsan structure solving
program obtained from the Rigaku Corp., Tokyo, J apan.26
Neutral scattering factors were obtained from the standard
source.27 The structures were solved by a combination of direct
methods (MITHRIL9028 and SAPI9129) and DIRDIF.30 Unless
otherwise stated, non-hydrogen atoms were refined with
anisotropic thermal parameters and hydrogen atoms were
fixed at the calculated positions (C-H ) 0.95 Å) and were not
(26) teXsan, Crystal Structure Analysis Package; Rigaku Corp.:
Tokyo, J apan, 1985, 1992, and 1999.
(27) International Tables for X-Ray Crystallography; Kynoch
Press: Birmingham, 1975; Vol. 4.
(28) Gilmore, C. J . MITHRIL, an integrated direct methods computer
program; University of Glasgow: Glasgow, U.K., 1990.
(29) Fan, H.-F. Structure Analysis Programs with Intelligent Con-
trol: Rigaku Corp.: Tokyo, J apan, 1991.
(30) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.;
Garcia-Granda, S.; Gould, R. O.; Smits, J . M. M.; Smykalla, C. The
DIRDIF program system, Technical Report of the Crystallography
Laboratory; University of Nijmegen: Nijmegen, The Netherlands, 1992.
Crystallographic data and the results of refinements are
summarized in Table 6. Structure analysis was performed on

1568 Organometallics, Vol. 20, No. 8, 2001
Akita et al.
refined. The C2H atom in 12 was refined isotropically, and the
bridging hydrogen atoms of 3 and 10* were not included in
the refinements.
SHELXS97 least-squares refinement program.32 Non-hydrogen
atoms were refined with anisotropic thermal parameters. The
methyl hydrogen atoms were refined using the riding models,
and the other hydrogen atoms were fixed at the calculated
positions (C-H ) 0.95 Å) and not refined.
(ii) F or 6*. Diffraction measurements were made on a
Rigaku RAXIS IV imaging plate area detector with Mo KR
radiation (λ ) 0.710 69 Å). All the data collections were carried
out at -60 °C. Indexing was performed from these oscillation
images, which were exposed for 4 min. The crystal-to-detector
distance was 110 mm. Data collection parameters were as
follows: detector swing angle, 5°; number of oscillation images,
23; exposed time, 50 min. Readout was performed with a pixel
size of 100 µm × 100 µm.
Ack n ow led gm en t. We are grateful to the Yamada
Science Foundation for financial support of this re-
search. We thank J EOL, Ltd. for the measurement of
the FAB-MS spectrum of 6.
Su p p or tin g In for m a tion Ava ila ble: Experimental de-
tails for X-ray crystallography and crystallographic results.
This material is available free of charge via the Internet at
http://pubs.acs.org.
Crystallographic data and the results of refinements are
summarized in Table 4. The structural analysis was performed
on an IRIS O2 computer using the teXsan structure solving
program obtained from the Rigaku Corp., Tokyo, J apan.
Neutral scattering factors were obtained from the standard
source.27 In the reduction of data, Lorentz and polarization
corrections were made. An absorption correction was also
made.31
OM001009C
(31) Higashi, T. Shape, Program To Obtain Crystal Shape Using
CCD Camera; Rigaku Corp.: Tokyo, J apan, 1999.
(32) (a) Sheldrick, G. M. SHELXS-86: Program for crystal structure
determination; University of Go¨ttingen: Go¨ttingen, Germany, 1986.
(b) Sheldrick, G. M. SHELXL-97: Program for crystal structure
refinement; University of Go¨ttingen: Go¨ttingen, Germany, 1997.
The structures were solved by a combination of direct
methods (SHELXS 86)32 and DIRDIF28 and refined with the