Ruthenium or ferrocenyl homobimetallic and RuPdRu and FePdFe heterotrimetallic complexes connected by unsaturated, carbon-rich -C=CC6H4C=C- bridges

Article abstract of DOI:10.1021/om960664a

The reaction of 1,4-diethynylbenzene with cis-RuCl₂(dppe)₂ and iodoferrocene gave the homobimetallic systems Cl(dppe)₂Ru-C≡CC₆H ₄C≡C-Ru(dppe)₂Cl (2) and (η⁵-C₅H_5<

Full text of DOI:10.1021/om960664a

184
Organometallics 1997, 16, 184-189
Ru th en iu m or F er r ocen yl Hom obim eta llic a n d Ru P d Ru
a n d F eP d F e Heter otr im eta llic Com p lexes Con n ected by
Un sa tu r a ted , Ca r bon -Rich -CtCC6H4CtC- Br id ges
Olivier Lavastre, J an Plass, Petra Bachmann, Salaheddine Guesmi,
Claude Moinet, and Pierre H. Dixneuf*
Laboratoire de Chimie de Coordination Organique, URA CNRS 415, Campus de Beaulieu,
Universite´ de Rennes, 35042 Rennes, France
Received August 7, 1996X
The reaction of 1,4-diethynylbenzene with cis-RuCl2(dppe)2 and iodoferrocene gave the
homobimetallic systems Cl(dppe)2RusCtCC6H4CtCsRu(dppe)2Cl (2) and (η5-C5H5)Fe(η5-
C5H4)sCtCC6H4CtCs(η5-C5H4)Fe(η5-C5H5) (3), respectively. The organometallic terminal
alkynes Cl(dppe)2RusCtCC6H4CtCH (6) and (η5-C5H5)Fe(η5-C5H4sCtCC6H4CtCH) (8),
obtained by desilylation of the corresponding complexes Cl(dppe)2RusCtCC6H4CtCSiiPr3
(5) and (η5-C5H5)Fe(η5-C5H4sCtCC6H4CtCSiiPr3) (7), were used as key starting products
for access to the heterotrimetallic systems trans-(PnBu3)2Pd[-CtCC6H4CtCsRu(dppe)2-
Cl]2 (10; 53%) and trans-(PnBu3)2Pd[(-CtCC6H4CtCsC5H4-η5)Fe(η5-C5H5)]2 (11; 73%) by
reaction with PdCl2(PBu3)2. The cyclic voltammetry studies of the complexes 2 and 3 have
shown that the electrochemical response was strongly dependent on the connection type
between the two terminal organometallic fragments and the organic bridge and that the
insertion of the palladium moiety trans-Pd(PBu3)2 in the trimetallic complexes 10 and 11
induced totally different electrochemical behavior.
In tr od u ction
optical17-19 properties. The physical properties of the
resulting oligomers are expected to be directly related
to the extended delocalization along the polymeric
chain.20 This motivates the design of new monomeric
models in order to evaluate the capability of com-
munication between two metal centers M1 made pos-
sible by an organic bridge (A), according to the nature
of the metal-bridge linkage, and the influence of an
organometallic fragment “M2” in a conjugated organic
chain (B).
Conjugated oligomers and polymers1 have attracted
considerable attention due to their application in ma-
terials science as conductors2-5 or liquid crystal6,7
precursors and light-emitting diodes (LED’s).8-10 The
incorporation of transition metals into an oligomer chain
is a convenient way to significantly modify the physical
properties of the corresponding organic polymers.11 The
large variety of structures and electronic states of
organometallic fragments has allowed the generation
of new liquid crystal,12-14 magnetic,15,16 or nonlinear
* To whom correspondence should be addressed. E-mail: dixneuf@
univ-rennes1.fr.
X Abstract published in Advance ACS Abstracts, December 15, 1996.
(1) (a) Scherf, U.; Mu¨ller, K. Synthesis 1992, 23-38. (b) Diederich,
F.; Rubin, Y. Angew. Chem. 1992, 104, 1123-1145; Angew. Chem., Int.
Ed. Engl. 1992, 31, 1101-1123.
The 1,4-diethynylbenzene unit -CtCC6H4CtC- has
already been involved in organic and homometallic
polymers (Pd, Pt, or Ni)21,22 and even recently in
heterometallic Ru/Pd, Fe/Pd, or Fe/Ni oligomers.23 In
these oligomers, the bridge is directly connected via a
metal-carbon bond to metal centers (Ru, Pd, Ni) or
indirectly via the cyclopentadienyl ligand (ferrocene).
(2) Bloor, D. Chem. Br. 1995, 31, 385-387.
(3) Miller, J . S. Adv. Mater. 1993, 5, 587.
(4) Miller, J . S. Adv. Mater. 1993, 5, 671-676.
(5) Ofer, D.; Crooks, R. M.; Wrighton, M. S. J . Am. Chem. Soc. 1990,
112, 7869-7879.
(6) Martelock, H.; Greiner, A.; Heitz, W. Makromol. Chem. 1991,
192, 967-979.
(7) Yu, L.; Bao, Z. Adv. Mater. 1994, 6, 156-159.
(8) Bradley, D. D. C. Synth. Met. 1993, 54, 401-415.
(9) Ingana¨s, O.; Berggren, M.; Andersson, M. R.; Gustafsson, G.;
Hjertberg, T.; Wennerstro¨m, O.; Dyreklev, P.; Granstro¨m, M. Synth.
Met. 1995, 71, 2121-2124.
(16) Hmyene, M.; Yassar, A.; Escorne, M.; A., P.-G.; Garnier, F. Adv.
Mater. 1994, 6, 564-567.
(17) Frazier, C. C.; Guha, S.; Chen, W. P.; Cockerham, M. P.; Porter,
P. L. Polymer 1987, 28, 553-555.
(10) Greiner, A.; Bolle, B.; Hesemann, P.; Oberski, J . M.; Sander,
R. Macromol. Chem. Phys. 1996, 197, 113-134.
(11) (a) Manners, I. Chem Brit. 1996, 32, 46-49. (b) Nock, H.;
Buchmeiser, M.; Polin, J .; Lukasser, J .; J aitner, P.; Schottenberger,
H. Mol. Cryst. Liq. Cryst. 1993, 235, 237-244. (c) Caliendo, C.; Verona,
E.; D’Amico, A.; Urlani, A.; Infante, G.; Russo, M. V. Sens. Actuators,
B 1995, 24-25, 670-672.
(18) Blau, W. J .; Byrne, H. J .; Cardin, D. J .; Davey, A. P. J . Mater.
Chem. 1991, 1, 245-249.
(19) Marder, T.; Fyfe, H.; Mlekuz, M.; Stringer, G.; Taylor, N. In
Inorganic and Organometallic Polymers with Special Properties; NATO
ASI Series E; Laine, R., Ed.; Kluwer: Dordrecht, The Netherlands,
1992; Vol. 206, pp 331-344.
(12) Takahashi, S.; Takai, Y.; Morimoto, H.; Sonogashira, K. J .
Chem. Soc., Chem. Commun. 1984, 3-5.
(20) Frapper, G.; Kertesz, M. Inorg. Chem. 1993, 32, 732-740.
(21) Sonogashira, K.; Ohga, K.; Takahashi, S.; Hagihara, N. J .
Organomet. Chem. 1980, 188, 237-243.
(13) Dembek, A. A.; Burch, R. R.; Feiring, A. E. J . Am. Chem. Soc.
1993, 115, 2087-2089.
(22) Takahashi, S.; Sonogashira, K.; Morimoto, H.; Murata, E.;
Kataoka, S.; Hagihara, N. J . Polym. Sci., Polym. Chem. Ed. 1982, 20,
565-573.
(14) Altmann, M.; Enkelmann, V.; Lieser, G.; Bunz, U. H. F. Adv.
Mater. 1995, 7, 726-728.
(15) Posselt, D.; Badur, W.; Steiner, M.; Baumgarten, M. Synth. Met.
1993, 55-57, 3299-3304.
(23) Lavastre, O.; Even, M.; Dixneuf, P. H.; Pacreau, A.; Vairon, J .
P. Organometallics 1996, 15, 1530-1531.
S0276-7333(96)00664-4 CCC: $14.00 © 1997 American Chemical Society

Homobimetallic and Heterotrimetallic Complexes
Organometallics, Vol. 16, No. 2, 1997 185
Sch em e 1
We wish to report now (i) the synthesis of ruthenium
and ferrocenyl homobimetallic complexes connected by
1,4-diethynylbenzene, -CtCC6H4CtC- and by pal-
ladium-containing -CtCC6H4CtCsPd(L)2sCtCC6H4-
CtC- bridges and (ii) an electrochemical study of the
redox metal sites.
The preparation of a trimetallic system of type B, in
which two ruthenium moieties (M1) are connected by a
metal-containing bridge, was attempted via the initial
formation of the organometallic terminal alkyne 6
(Scheme 2), followed by the coupling of the CtCH end
of 6 to the organometallic fragment M2. cis-RuCl2-
(dppe)2 was first reacted with 1-((triisopropylsilyl)-
ethynyl)-4-ethynylbenzene28 4 in the presence of NaPF6
in THF to give a pale green intermediate, likely to be
the vinylidene [Cl(dppe)RudCdCH(C6H4CtCSiiPr3)]+-
PF6- salt. On deprotonation by NEt3 this intermediate
led to the yellow ruthenium complex 5 in good yield
(81%; Scheme 2) (31P{1H}NMR: δ (ppm) 49.94 (s,
PPh2)). Two CtC stretching vibrations were observed
in the IR at 2148 cm-1 for the silylated CtC bond and
2061 cm-1 for the ruthenium acetylide moiety. Desilyl-
ation of compound 5 by NBu4F‚3H2O in THF led to the
ruthenium acetylenic complex 6 as a yellow solid (92%;
Scheme 2). Spectroscopic data for 6 were identical with
those of the complex 5 except for the acetylenic end
group. In the IR the tCH and CtCH stretching
Resu lts a n d Discu ssion
P r ep a r a tion of Com p lexes. The synthesis of a
RusCtCC6H4CtCsRu unit was attempted by the
activation of 1,4-diethynylbenzene (1) via the expected
vinylidene intermediate followed by deprotonation, as
was shown to occur from RuCl2(diphosphine)2 complexes
and terminal monoalkynes.24 This approach is in
contrast with classical metal-carbon bond formation via
a metal-halide unit and an organometallic.25 Thus, the
yellow bimetallic ruthenium derivative 2 was made in
58% yield by the reaction of 1,4-diethynylbenzene (1)
and 2 equiv of cis-RuCl2(dppe)2 (dppe ) Ph2PCH2CH2-
PPh2) in the presence of NaPF6 in THF (Scheme 1). A
pale green intermediate formed, likely to be a vi-
nylideneruthenium species, and was deprotonated by
NEt3. The 31P{1H} NMR of the yellow complex 2
showed only a singlet at 50.31 ppm (PPh2) for the eight
equivalent 31P nuclei, in accord with a trans-chloroalky-
nylruthenium compound.
The carbon-carbon coupling of the same bridge with
two ferrocene groups was attempted by a classical cross-
coupling reaction.26 Two equivalents of the iodofer-
rocene27 was reacted with 1 equiv of 1,4-diethynylben-
zene (1), in the presence of catalytic amounts of
PdCl2(PPh3)2/Cu(OAc)2 in HNiPr2 at 90 °C, which gave
the complex 3 as a brown-red solid (95%) (13C{1H}
NMR: δ (ppm) 90.21 and 85.71 (s, CtC)).
vibrations were observed at 3226 and 2036 cm-1
,
respectively, and in the 13C{1H} NMR signals appeared
for the CtCH end group (84.99 and 77.19 ppm) and the
ruthenium acetylide RusC≡C (δ (ppm) 136.38 (quint,
2
CR, J PC ) 12 Hz), 130.36 (s, Câ).
The catalytic coupling of iodoferrocene with the sily-
lated diyne 4 in HNiPr2 at 90 °C by PdCl2(PPh3)2/Cu-
(OAc)2 catalysts gave the red ferrocenyl derivative 7
(64%; Scheme 2). The acetylenic moieties were char-
acterized by IR (νFcCtC 2207 cm-1, νSiCtC 2151 cm-1) and
by 13C{1H} NMR (δ 107.2 and 92.9 ppm (CtCSi), 91.1
and 85.5 (CtCsCp)). Desilylation of 7 by treatment
with NBu4F‚3H2O in THF gave the orange-red crystal-
line complex 8 (91%). By using the protection by SiiPr3
and the deprotection to give the CtCH end, no con-
tamination of 6 and 8 by 2 and 3, respectively, was
observed.
(24) Touchard, D.; Morice, C.; Cadierno, V.; Haquette, P.; Toupet,
L.; Dixneuf, P. H. J . Chem. Soc., Chem. Commun. 1994, 859.
(25) (a) Lo Sterzo, C.; Stille, J . K. Organometallics 1990, 9, 687-
694. (b) Crescenzy, R.; Lo Sterzo, C. Organometallics 1992, 11, 4301-
4305. (c) Viola, E.; Lo Sterzo, C.; Trezzi, F. Personal Communication.
(26) (a) Takahashi, S.; Kuroyama, Y.; Sonogashira, K.; Hagihara,
N. Synthesis 1980, 627. (b) Pudelski, J . K.; Callstrom, M. R. Organo-
metallics 1992, 11, 2757-2759.
Complexes 6 and 8, which contain one reactive
terminal acetylenic end CtCH, are key starting materi-
als for access to trimetallic systems. By reaction of 2
(27) Guillaneux, D.; Kagan, H. B. J . Org. Chem. 1995, 60, 2502-
2505.
(28) Lavastre, O.; Ollivier, L.; Dixneuf, P. H.; Sibandhit, S. Tetra-
hedron 1996, 52, 5495-5504.

186 Organometallics, Vol. 16, No. 2, 1997
Lavastre et al.
Sch em e 2
Sch em e 3
equiv of the complex Cl(dppe)2Ru-CtCC6H4CtC-H (6)
and 1 equiv of PdCl2(PBu3)2 (9), the yellow compound
10, containing two ruthenium monoacetylide chains
connected via a palladium diacetylide moiety, was
produced in 50% yield (Scheme 3). The palladium-
carbon bonds were formed in HNEt2 in the presence of
a catalytic amount of CuI. The 31P{1H} NMR showed
singlets at 50.82 ppm (PPh2) and 12.36 ppm (PBu3)
characteristic of a trans arrangement for all metal
centers. In IR, the ruthenium and palladium acetylide
moieties were merged into one vibration band at 2065
cm-1 although they are clearly differentiated in 13C{1H}
NMR (δ (ppm) 137.42 (quintet, RusCtC, 2J PC ) 10 Hz),
111.94 (t, PdsCtC, 2J PC ) 12 Hz), 111.91 (t, PdsCtC,
3J PC ) 3 Hz).
A singlet at 11.84 ppm in the 31P{1H} NMR was
observed, characteristic of a palladium diacetylide com-
plex in a trans geometry.
Electr och em ica l Stu d ies. In order to evaluate the
influence of the nature of the terminal organometallic
fragment-bridge connection and of the insertion of an
organometallic fragment into an conjugated organic
chain, the cyclic voltammetry of complexes containing
ruthenium (2, 5, 6, 10) and ferrocene (3, 7, 8, 11) was
measured in dichloromethane containing NBu4PF6 salt
at 100 mV s-1 with respect to the saturated calomel
electrode (VSCE) (Table 1).
The neutral compound 2 showed two successive
reversible oxidation waves (E° ) +0.15 (ip,a/ip,c )1.06)
and +0.55 VSCE (ip,a/ip,c) 1.03)) which could be attributed
to the formation of the mono- and dications respectively,
corresponding to the formation of the RuIII/RuII and
RuIII/RuIII systems. For the two redox systems, the
anodic and cathodic peak separation was 80 mV (with-
out correction of the ohmic drop) with a 100 mV s-1 scan
rate. The first oxidation of compound 2 was much easier
(Ep,a ) 0.19 VSCE) than that of the corresponding
The similar procedure applied to the ferrocene-
containing alkyne 8 gave the trimetallic complex 11 in
73% yield (scheme 3). The ferrocenyl and palladium
acetylide fragments were very distinct in the IR (νFcCtC
2207 cm-1, νPdCtC 2095 cm-1) and 13C{1H} NMR (δ
2
(ppm) 116.0 (t, PdsCtC, J PC ) 17 Hz), 111.4 (t,
3
PdsCtC, J PC ) 4 Hz), 89.63 and 87.08 (s, FcsCtC).

Homobimetallic and Heterotrimetallic Complexes
Organometallics, Vol. 16, No. 2, 1997 187
Ta ble 1. Cyclic Volta m m etr y Da ta for Com p lexes
Fc moieties (∆E ) 260 mV), although the bridge, an
organometallic one, was connected to the cyclopentadi-
enyl ligands.
2-11a
Ep,a Ep,c E°
(V) (V) (V) (mV) (V)
∆E
E′p,a
compdb
Monometallic ruthenium derivatives 5 and 6 showed
similar electrochemical responses with the first revers-
ible oxidation wave (RuIII/RuII, E° ) 0.52 VSCE (ip,a/ip,c
) 0.98) followed by a second irreversible oxidation wave
attributed to the redox system RuIV/RuIII. Monoferro-
cenyl complexes 7 and 8 gave in cyclic voltammetry a
single oxidation wave (E° ) 0.58 VSCE) in the range
0-1.7 V.
More interesting was the cyclic voltammogram of
complex 10. It showed the first large (∆E )110 mV)
reversible (ip,a/ip,c ) 0.99) oxidation wave at E° ) 0.33
VSCE (RuIII/RuII) and two irreversible oxidation waves
[Ru]sCtCC6H4CtCs[Ru] (2)
0.19 0.11 0.15
0.55 0.47 0.51
0.51 0.43 0.47
0.53 0.44 0.49
80 1.6c
80
[Ru]sCtCC6H4CtCsSiiPr3 (5)
[Ru]sCtCC6H4CtCsH (6)
80 1.36c
90 1.38c
[Pd]s(CtCC6H4CtCs[Ru])2 (10) 0.39 0.28 0.33 110 1.14e
1.38e
FcsCtCC6H4CtCs[Fc] (3)
[Fc]sCtCC6H4CtCsSiiPr3 (7)
[Fc]sCtCC6H4CtCH (8)
0.64 0.48 0.56 160
0.62 0.54 0.58 80
0.64 0.52 0.58 120
[Pd]s(CtCC6H4CtCs[Fc])2 (11) 0.61 0.50 0.55 110 1.42d
a
Conditions: in CH2Cl2, NBu4PF6, 100 mV/s scan rate, Pt
working and counter electrodes (1 mm diameter), ECS reference
electrode, [complex] ) 1 × 10-3-2 × 10-3 M. A calibration
voltammogram with ferrocene (E°′) 0.49 V) was recorded before
at more positive potential (E′p,a ) 1.14 and 1.38 VSCE
)
b
attributed to the RuIV/RuIII and PdIII/PdII redox systems.
The first wave corresponds to the oxidation of the two
ruthenium centers, as was verified by voltammetry with
a rotating Pt electrode (2000 rpm). The wave corre-
sponding to the process RuII f RuIII disappeared
completely to the benefit of the wave RuIII f RuII after
the addition to complex 10 of 2 equiv of 2,3-dichloro-
5,6-dicyano-1,4-benzoquinone (DDQ; E° ) 0.50 VSCE in
CH2Cl2).33 This is in contrast with the result observed
for compound 2. To first approximation the palladium
moiety seems to inhibit communication between the two
ruthenium centers; this phenomenon has just been
observed for the trimetallic complex LnResCtCsPd-
each measurement. Abbreviations: [Ru] ) ClRu(dppe)2; [Pd] )
Pd(PnBu3)2; [Fc] ) (η5-C5H5)Fe(η5-C5H4). c Irreversible oxidation
d
(RuIV/RuIII). Irreversible oxidation (PdIII/PdII). e Irreversible oxi-
dations (RuIV/RuIIIand PdIII/PdII).
monometallic complexes 5 and 6 (Ep,a ) 0.51 and 0.53
VSCE, respectively). This difference is due to a greater
electron-donating capability, through a -CtCC6H4CtC-
bridge, of the ruthenium(II) moiety ClRu(dppe)2 in 2
than the H and SiiPr3 groups in 6 and 5, respectively.
The E° values for the two redox processes differed by
360 mV, clearly indicating a communication between
the two ruthenium centers through the 1,4-diethynyl-
benzene bridge. Interestingly, a binuclear compound
containing the same conjugated bridge, (η5-C5Me5)(η2-
dppe)FesCtCC6H4CtCsFe(η5-C5Me5)(η2-dppe) has just
been reported to show a smaller difference (∆E0 ) 260
mV) between the oxidation potential of iron-centered
redox systems.29 These results indicated that the
nature of the terminal metal centers (ClRu(dppe)2- or
(η5-C5Me5)(η2-dppe)Fe-) can influence the electrochemi-
cal response of the corresponding bimetallic systems on
the basis of the same organic bridge.
34
(PBu3)2sCtC-ReLn where the palladium(II) moiety
associated with the same two PBu3 ligands was de-
scribed as an insulating block for the conjugated chain.
Derivative 11 showed a wave at E° ) 0.55 VSCE (ip,a
/
ip,c ) 1.02) corresponding to the two-electron oxidation
of the two terminal ferrocenyl moieties, as was con-
firmed by voltammetry with a rotating Pt electrode
(2000 rpm) and 2 equiv of AgBF4 as oxidant.33a In
addition, 11 showed an irreversible oxidation wave at
E° ) 1.42 V for the PdIII/PdII redox system.
This can be seen from the study of the biferrocenyl
complex 3 which showed in cyclic voltammetry a single,
but large, oxidation wave (E° ) + 0.56 VSCE (ip,a/ip,c
)
Con clu sion
1.03), ∆E ) 160 mV). No significant difference was
observed with the corresponding monometallic deriva-
tives 7 (E° ) + 0.58 VSCE (ip,a/ip,c ) 1.01)) and 8 (E° )
+ 0.58 VSCE (ip,a/ip,c ) 0.99)) containing the SiiPr3 and
H groups. Biferrocenyl derivatives bridged by acetylenic
linkages FcsCtCsFc and FcsCtCCtCsFc have al-
ready been described and showed similar cyclic volta-
mmograms with quite large waves (∆E )100-130
mV).30,31 This observation was analyzed as superim-
posed one-electron waves rather than two-electron
oxidations, where a lower difference (∆E e 80 mV) was
expected. Also, it is tempting to explain the small
difference between the oxidation potential of the iron
redox centers in 3 by the fact that the organic 1,4-
diethynylbenzene bridge is connected to the cyclopen-
tadienyl ligands and not directly to the metal centers
as in complex 2. However, this simple hypothesis is not
in agreement with the recently reported biferrocenyl
derivative FcsCtCsPtsCtCsFc,32 which showed two
well-resolved reversible oxidation waves centered on the
In summary, we have reported new bimetallic sys-
tems containing an organic or metal-containing conju-
gated bridge; whereas the ferrocene precursor was made
by a classical catalyzed cross-coupling reaction, the
ruthenium derivative was produced by activation of
terminal diynes by ruthenium(II) moieties and via
vinylidene intermediates. Electrochemistry studies have
shown (i) that the electrochemical behavior of bimetallic
complexes was strongly dependent on the nature of the
connection between the two terminal organometallic
fragments and the 1,4-diethynylbenzene bridge and (ii)
that the incorporation of the organometallic fragment
trans-Pd(PBu3)2 in the conjugated bridge induced dif-
ferent electrochemical behavior. Studies are currently
in progress to apply these results to promote or inhibit
electron delocalization in metal-containing conjugated
polymers.
(32) Osella, D.; Milone, L.; Nervi, C.; Ravera, M. J . Organomet.
Chem. 1995, 488, 1-7.
(29) Le Narvor, N.; Lapinte, C. Organometallics 1995, 14, 634-639.
(30) Levanda, C.; Bechgaard, K.; Cowan, D. O. J . Org. Chem. 1976,
41, 2700-2704.
(31) Kramer, J . A.; Hendrickson, D. N. Inorg. Chem. 1980, 19, 3330-
3337.
(33) (a) Connelly, N. G.; Geiger, W. E. Chem. Rev. 1996, 96, 877-
910. (b) Sato, M.; Mogi, E.; Katada, M. Organometallics 1995, 14,
4837-4843.
(34) Weng, W. Q.; Bartik, T.; Brady, M.; Bartik, B.; Ramsden, J . A.;
Arif, A. M.; Gladysz, J . A. J . Am. Chem. Soc. 1995, 117, 11922-11931.

188 Organometallics, Vol. 16, No. 2, 1997
Lavastre et al.
3
(d, 2H, C6H4, J HH ) 8 Hz), 2.66 (m, CH2CH2), 1.14 (m, SiiPr).
31P{1H} NMR (121.499 MHz, CDCl3, 297 K): δ (ppm) 49.94
(s, dppe).
Exp er im en ta l Section
Gen er a l Da ta . Solvents were dried by standard methods,
and all reactions involving metal complexes were conducted
under nitrogen by standard Schlenk techniques. Elemental
analysis were performed by the CNRS analyses laboratory,
Villeurbanne, France. NMR spectra were recorded on a
Bruker AMWB 300 operating at 300.134 MHz for 1H, 75.469
MHz for 13C, and 121.496 MHz for 31P nuclei or on a Bruker
DPX 200 operating at 200.131 MHz for 1H and 81.019 MHz
for 31P nuclei; 31P chemical shifts are relative to external H3-
PO4 (85%). Mass spectra were performed at the CRMPO
Cl(d p p e)2Ru sCtCC6H4CtCH (6). To a solution of the
silylated product 5 (900 mg, 0.70 mmol) in THF (15 mL) was
added a solution of Bu4NF‚3H2O (110 mg, 0.35 mmol) in THF
(10 mL) dropwise. The mixture was stirred at room temper-
ature for 30 min. After evaporation of the solvent the crude
material was washed with water (4 × 15 mL) and dissolved
in methylene dichloride (15 mL). After evaporation of the
organic layer the solid was dissolved in toluene (15 mL).
Evaporation of the toluene layer and washing with pentane
center (university of Rennes) on
a Zab Spec TOF mass
yielded 732 mg of a yellow solid (93%). Anal. Calcd for C62H53
-
,
ClP4Ru: C, 70.35; H, 5.05. Found: C, 69.61; H, 5.13. IR (cm-1
spectrometer (FAB positive mode). Glycerol was used as the
matrix for the FAB spectra. The synthesis of cis-RuCl2-
(dppe)2,35 iodoferrocene,27 1,4-diethynylbenzene,28 and 1-((tri-
isopropylsilyl)ethynyl)-4-ethynylbenzene28 was performed as
previously described.
KBr): 3226 (νtCH), 2066 (νCtCRu). 1H NMR (300.133 MHz,
CDCl3, 297 K): δ (ppm) 7.45-6.91 (m, C6H5 and C6H4), 6.51
(d, 2H, C6H4, 3J HH ) 8 Hz), 3.10 (s, C≡CH), 2.68 (m, CH2CH2).
31P{1H} NMR (121.499 MHz, CDCl3, 297 K): δ (ppm) 49.83
(s, dppe). 13C{1H} NMR (75.469 MHz, CD2Cl2, 297 K): δ (ppm)
Cl(dppe)2Ru sCtCC6H4CtCsRu (dppe)2Cl (2). cis-RuCl2-
(dppe)2 (500 mg, 0.52 mmol), 1,4-diethynylbenzene (1; 33 mg,
0.26 mmol), and NaPF6 (173 mg, 1.03 mmol) are stirred in
THF (20 mL) for 40 h. After filtration the green solid is
washed with pentane. THF (20 mL) and triethylamine (1 mL)
were added to the solid. The reaction mixture was stirred for
16 h at room temperature. After filtration and washing with
pentane a yellow product was obtained (0.310 g, 58% yield).
It was recrystallized in CH2Cl2. High-resolution mass spec-
trometry: M+ calcd 1991.3232, found: 1991.329. Anal. Calcd
for C114H100Cl2P8Ru2.2CH2Cl2: C, 64.50; H, 4.86. Found: C,
64.20; H, 4.74. IR (cm-1, KBr): 2058 (νCtCRu). 1H NMR
(300.133 MHz, C6D6, 297 K): δ (ppm) 7.70-6.92 (m, C6H5 and
C6H4), 2.66 (m, CH2CH2). 31P{1H} NMR (121.499 MHz, C6D6,
297 K): δ (ppm) 50.31 (s, dppe). 13C{1H} NMR (75.469 MHz,
CD2Cl2, 297 K): δ (ppm) 135.19, 134.93, 129.31, 129.03, 127.90,
127.33, 30.59 (m, CH2).
(η5-C5H 5)F e (η5-C5H 4sCtCC6H 4CtCsC5H 4-η5)F e (η5-
C5H5) (3). Iodoferrocene (1.0 g, 3.2 mmol), 1,4-diethynylben-
zene (1; 202 mg, 1.6 mmol), bis(triphenylphosphine)palladium
dichloride (91 mg, 0.13 mmol), and copper acetate (24 mg, 0.13
mmol) were dissolved in diisopropylamine (25 mL). The
reaction mixture was stirred for 17.5 h at 90 °C. The brown
solid obtained by removing the solvent in vacuo was dissolved
in CH2Cl2 (25 mL) and washed with water (3 × 10 mL).
Evaporation of the dichloromethane layer and washing with
pentane (3 × 15 mL) provided 754 mg (1.53 mmol) of a brown-
red solid (96%). High-resolution mass spectrometry: M+ calcd
494.0421, found 494.042. Anal. Calcd for C30H22Fe2: C, 72.87;
H, 4.49. Found: C, 72.55; H, 4.78. IR (cm-1, KBr): 2200
(νCtC). 1H NMR (300.133 MHz, C6D6, 297 K): δ (ppm) 7.36
(s, C6H4), 4.46 (m, C5H4), 4.07 (s, C5H5), 3.94 (m, C5H4). 13C-
{1H} NMR (75.469 MHz, CDCl3, 297 K), δ (ppm) 131.2 (s, CH
of C6H4), 123.1 (s, Cipso of C6H4), 90.2 and 85.7 (s, C≡C), 71.5
and 69.0 (s, CH of C5H4), 70.0 (s, C5H5), 65.1 (s, Cipso of C5H4).
2
136.38 (quint, RusC, J PC ) 12 Hz), 134.99, 134.37, 131.66,
129.46, 129.19, 127.58, 127.42 (C6H5 and C6H4), 130.36 (s, Ru-
C≡C), 115.73 and 113.96 (s, Cipso of C6H4), 84.99 (s, C≡CH),
77.19 (s, C≡CH), 30.99 (CH2CH2).
(η5-C5H5)F e(η5-C5H4sCtCC6H4CtCSiiP r 3) (7). Iodofer-
rocene (2.0 g, 6.4 mmol), 4 (1.7 g, 6.7 mmol), bis(triphenylphos-
phine)-palladium dichloride (175 mg, 0.25 mmol), and copper
acetate (45 mg, 0.25 mmol) were stirred for 17.5 h at 90 °C in
diisopropylamine (40 mL). The brown oil obtained by remov-
ing the amine in vacuo was extracted with pentane (4 × 30
mL). After filtration and evaporation of the solvent a brown
oil was obtained, which was purified via column chromatog-
raphy (Al2O3, CH2Cl2/pentane 1:10). Evaporation of the
solvents yielded 1.9 g of a red oil (64%). High-resolution mass
spectrometry: M+ calcd 466.1780, found: 466.177. Anal.
Calcd for C29H34FeSi: C, 74.65; H, 7.35. Found: C, 74.13; H,
7.33. IR (cm-1, KBr): 2207 (νCtCFc), 2151 (νCtCSi). 1H NMR
(300.133 MHz, CDCl3, 297 K): δ (ppm) 7.40 (s, C6H4), 4.49
(m, C5H4), 4.24 (m, C5H4), 4.15 (s, C5H5), 1.12 (m, SiiPr).
13C{1H} NMR (75.469 MHz, CD2Cl2, 297 K): δ (ppm) 132.3
and 131.5 (s, CH of C6H4), 124.4 and 123.0 (s, Cipso of C6H4),
107.2 (s, CtCSi), 92.9 (s, CtCSi), 91.1 and 85.1 (s, CtCC5H4),
71.9, 70.4, 69.5, and 68.4 (C5H5 and C5H4), 18.9 (CH3), 11.7
(CH).
(η5-C5H5)F e(η5-C5H4sCtCC6H4CtCH) (8). To a solution
of the silylated complex 7 (1.0 g, 2.2 mmol) in THF (30 mL)
was added dropwise a solution of Bu4NF‚3H2O (694 mg) in
THF (15 mL). The mixture was stirred for 10 min at room
temperature. After evaporation of the solvent the crude
material was dissolved in toluene (25 mL) and washed with
water (3 × 15 mL). The dark orange oil obtained by evapora-
tion of the toluene layer was further purified via column
chromatography (Al2O3, CH2Cl2/hexane 1:10), which yielded
620 mg (2.0 mmol) of an orange-red crystalline material (91%).
High resolution mass spectrometry: M+ calcd 310.0445, found
Cl(d p p e)2Ru sCtCC6H4CtCSiiP r 3 (5). cis-RuCl2(dppe)2
(962 mg, 0.99 mmol), 1-((triisopropylsilyl)ethynyl)-4-ethynyl-
benzene (4; 563 mg, 1.98 mmol), and NaPF6 (169 mg, 1 mmol)
were stirred in methylene dichloride (20 mL) for 15 h. After
filtration and evaporation of solvent a green solid was obtained
and washed with pentane to eliminate excess 4. The green
solid was dissolved in THF (30 mL) to give a red solution.
Triethylamine (0.7 mL, 5.22 mmol, 6 equiv) was added, and
the reaction mixture was stirred for 4 h at room temperature.
The yellow solid obtained by removing the solvent in vacuo
was dissolved in toluene (20 mL) and filtered. Evaporation of
the toluene and washing with pentane yielded 973 mg (0.73
mmol) of a yellow solid (81%). Anal. Calcd for C71H73ClP4-
310.045. Anal. Calcd for
C20H14Fe: C, 77.41; H, 4.65.
Found: C, 77.46; H, 5.47. IR (cm-1, KBr): 3269 (νtCH), 2203
(νCtCFc), 2103 (νCtC). 1H NMR (300.133 MHz, CDCl3, 297 K):
δ (ppm) 7.45 (s, C6H4), 4.50 (m, C5H4), 4.27 (m, C5H4), 4.24 (s,
C5H5), 3.16 (s, CtCH).
(P n Bu 3)2P d [-CtCC6H4CtCsRu (d p p e)2Cl]2 (10). The
ruthenium complex 6 (600 mg, 0.56 mmol), PdCl2(PBu3)2 (9;
162 mg, 0.28 mmol), and copper iodide (1 mg, 0.005 mmol)
were dissolved in diethylamine (15 mL) and THF (5 mL). The
reaction mixture was stirred for 20 h at room temperature.
The yellow-ocher solid obtained by removing the solvent in
vacuo was dissolved in toluene (30 mL) and washed with water
(3 × 20 mL). Evaporation of the toluene layer yielded a yellow-
ocher solid. This procedure provided 491 mg (75%) of crude
product. Recrystallization in toluene/pentane gave 365 mg of
a yellow solid (53%). High-resolution mass spectrometry: M+
SiRu: C, 70.20; H, 6.06. Found: C, 70.64; H, 6.27. IR (cm-1
,
KBr): 2148 (νCtCSi), 2061 (νCtCRu). 1H NMR (300.133 MHz,
CDCl3, 297 K): δ (ppm) 7.44-6.91 (m, C6H5 and C6H4), 6.50
calcd 2624.6249, found 2624.726. Anal. Calcd for C148H158
Cl2P10PdRu2: C, 67.67; H, 6.07. Found: C, 67.48; H, 6.05. IR
-
(35) Chaudret, B.; Commenges, G.; Poilblanc, R. J . J . Chem. Soc.,
Dalton Trans. 1984, 1635-1639.

Homobimetallic and Heterotrimetallic Complexes
Organometallics, Vol. 16, No. 2, 1997 189
(cm-1, KBr): 2066 (νRuCtC and νPdCtC). 1H NMR (200.131 MHz,
C6D6, 297 K): δ (ppm) 7.81, 7.69, and 7.07 (m, C6H5 and C6H4),
2.74 (m, PCH2CH2P), 2.24, 1.91, and 1.64 (m, CH2), 1.12 (t,
CH3, 3J HH ) 7 Hz). 31P{1H} NMR (81.019 MHz, C6D6, 297 K):
C5H4), 27.59 (s, CH2CH3), 25.99 (m, PCH2CH2), 24.84 (m,
PCH2CH2), 14.45 (s, CH3).
Cyclic Volta m m etr y. Voltammograms were recorded on
an EG&G Princeton Applied Research Model 362 scanning
potentiostat. Conditions: CH2Cl2 solvent, NBu4PF6 (0.1 M)
electrolyte, 100 mV/s scan rate, Pt working and counter
electrodes (1 mm diameter), ECS reference electrode. Con-
centrations of organometallic complexes were 1 × 10-3 to 2 ×
10-3 M. A calibration voltammogram with ferrocene (E° )
0.49VSCE) was recorded before each measurement. Potentials
have been not corrected for ohmic drop.
δ (ppm) 50.83 (s, PPh2), 12.36 (s, PBu3). 13C{1H} NMR (75.469
2
MHz, C6D6, 297 K): δ (ppm) 137.42 (quint, RusCtC, J PC
)
10 Hz), 135.63, 135.05, 130.95, 130.84, 129.55, 129.44 and
129.32 (m, C6H5, C6H4, RusC≡C), 124.39 (s, PdsCtCC),
2
114.29 (s, RusCtCC), 111.94 (t, PdsCtC, J PC ) 12 Hz),
111.91 (t, PdsCtC, 3J PC ) 3 Hz), 31.51 (m, dppe CH2), 27.66,
26.05, and 25.40 (PBu3 CH2), 14.59 (CH3).
(P n Bu 3)2P d [(-CtCC6H4CtC-C5H4-η5)F e(η5-C5H5)]2 (11).
Compound 8 (300 mg, 0,97 mmol), PdCl2(PBu3)2 (9; 290 mg,
0,49 mmol), and copper iodide (6 mg, 0.032 mmol) were
dissolved in diethylamine (20 mL). The reaction mixture was
stirred for 20 h at room temperature. The orange oil obtained
by removing the amine in vacuo was dissolved in toluene (25
mL) and washed with water (4 × 15 mL). Evaporation of the
toluenic layer yielded an orange oil, which was washed by
pentane. This procedure provided 410 mg (0.36 mmol) of an
orange crystalline material (73%). High-resolution mass spec-
trometry: M+ calcd 1128.3490, found 1128.345. Anal. Calcd
for C64H80Fe2P2Pd: C, 68.08; H, 7.14. Found: C, 67.82; H,
7.32. IR (cm-1, KBr): 2207 (νFcCtC), 2095 (νPdCtC). 1H NMR
(200.131 MHz, C6D6, 297 K): δ (ppm) 7.53 (s, C6H4), 4.45 (m,
C5H4), 4.06 (s, C5H5), 3.92 (m, C5H4), 1.98, 1.65, and 1.38 (m,
Volta m m etr y w ith Rota tin g Electr od e. Voltamograms
were recorded before and after addition of the chemical redox
reagents with a Pt (1 mm diameter) rotating electrode (2000
rpm) with a sweep rate of 100 mV/s in CH2Cl2 (30 mL) with
NBu4PF6 (200 mg) as electrolyte. Voltamograms were re-
corded 10 min after the addition of 4.3 mg (1.9 × 10-5 mol) of
DDQ to 25 mg (9.5 × 10-6 mol) of complex 10 and 30 min after
the addition of 12 mg (6 × 10-5 mol) of AgBF4 to 34 mg (3 ×
10-5 mol) of complex 11.
Ack n ow led gm en t. We wish to thank the CNRS and
the European Union (Contract ERBCHRXCT 94-0501)
for support, the University Chouaib Doukkali of El
J adida, Morocco, for a leave of absence to S.G., the
European Erasmus Programme for an undergraduate
grant to J .P. from the University of Hamburg and the
Procope Programme for a grant to P.B. of the University
of Wu¨rzburg.
3
CH2), 0.89 (t, CH3, J HH ) 6.0 Hz). 31P{1H} NMR (121.499
MHz, C6D6, 297 K): δ (ppm) 11.84 (s, PBu3). 13C{1H} NMR
(75.469 MHz, C6D6, 297 K): δ (ppm) 132.09 and 131.50 (s, CH
3
of C6H4), 121.13 (s, Cipso C6H4), 115.98 (t, CtCPd, J PC ) 7.0
Hz), 111.36 (s, CtCPd), 89.63 and 87.08 (s, CtCC5H4), 72.17
(s, CH C5H4), 70.72 (s, C5H5), 69.52 (s, CH C5H4), 66.36 (s, Cipso
OM960664A