Ferrocene-containing (η6-Hexamethylbenzene)ruthenium(II) methoxycarbenes: Synthesis, structure, and electrochemistry

Article abstract of DOI:10.1021/om970478k

The (η⁶-hexamethylbenzene)dichlororuthenium(II) complexes [(η⁶-C₆Me₆)RuCl₂(L)], where L = PMe₃ (1), PPh₃ (2), FcPPh₂ (3; Fc = ferrocenyl), and Hdpf (4; Hdpf = (η⁵-C₅H₄PPh₂)Fe(η ⁵-C₅H₄COOH)), were reacted with terminal alkynes (FcC≡CH, Me₃SiC≡CH, and PhC≡CH) in the presence of NaPF₆ and methanol to give (η⁶-hexamethylbenzene)chlororuthenium(II) methoxycarbenes [(η⁶-C₆Me₆)RuC=C(OCH₃)CH ₂R)Cl(L)]PF₆ (L/R = PMe₃/Fc (1a), PPh₃/Fc (2a), FcPPh₂/Fc (3a), FcPPh₂/H (3b), FcPPh₂/Ph (3c), Hdpf/Fc (4a), Hdpf/H (4b), and Hdpf/ Ph (4c)). All new compounds were characterized by NMR and IR spectroscopy and also studied by mass spectrometry in liquid matrix. The solid-state structure of 4a·CH₂Cl₂ was determined by single-crystal X-ray diffraction. The electrochemical study of these bi- and trimetallic complexes displayed that upon oxidation, the Ru-ferrocenyl phosphine moiety undergoes a ferrocene/ferrocenium redox process followed by a Ru(II) → Ru(III) oxidation which is, however, markedly influenced by the preceding redox change. A redox dissymmetry of carbenes 1a-4c was observed, as these exhibit communication within the Ru-phosphine part while the carbene ferrocenyl group remains isolated and practically unaffected.

Full text of DOI:10.1021/om970478k

Organometallics 1997, 16, 5089-5095
5089
F er r ocen e-Con ta in in g
(η6-Hexa m eth ylben zen e)r u th en iu m (II) Meth oxyca r ben es:
Syn th esis, Str u ctu r e, a n d Electr och em istr y
Petr Sˇteˇpnicˇka* and Ro´bert Gyepes
Department of Inorganic Chemistry, Charles University, Hlavova 2030,
12840 Prague, Czech Republic
Olivier Lavastre and Pierre H. Dixneuf
Chimie de Coordination et Catalyse, UMR 6509, CNRS, Universite´ de Rennes I,
Campus de Beaulieu, 35042 Rennes, France
Received J une 9, 1997X
The (η6-hexamethylbenzene)dichlororuthenium(II) complexes [(η6-C6Me6)RuCl2(L)], where
L ) PMe3 (1), PPh3 (2), FcPPh2 (3; Fc ) ferrocenyl), and Hdpf (4; Hdpf ) (η5-C5H4PPh2)Fe(η5-
C5H4COOH)), were reacted with terminal alkynes (FcCtCH, Me3SiCtCH, and PhCtCH)
in the presence of NaPF6 and methanol to give (η6-hexamethylbenzene)chlororuthenium(II)
methoxycarbenes [(η6-C6Me6)Ru(dC(OCH3)CH2R)Cl(L)]PF6 (L/R ) PMe3/Fc (1a ), PPh3/Fc
(2a ), FcPPh2/Fc (3a ), FcPPh2/H (3b), FcPPh2/Ph (3c), Hdpf/Fc (4a ), Hdpf/H (4b), and Hdpf/
Ph (4c)). All new compounds were characterized by NMR and IR spectroscopy and also
studied by mass spectrometry in liquid matrix. The solid-state structure of 4a ‚CH2Cl2 was
determined by single-crystal X-ray diffraction. The electrochemical study of these bi- and
trimetallic complexes displayed that upon oxidation, the Ru-ferrocenyl phosphine moiety
undergoes a ferrocene/ferrocenium redox process followed by a Ru(II) f Ru(III) oxidation
which is, however, markedly influenced by the preceding redox change. A redox dissymmetry
of carbenes 1a -4c was observed, as these exhibit communication within the Ru-phosphine
part while the carbene ferrocenyl group remains isolated and practically unaffected.
In tr od u ction
cene/ferrocenium redox systems according to their pos-
sible communication, the ferrocene-containing ruthe-
nium(II) carbenes of the general formula [(η6-arene)-
Ru(dC(OMe)CH2R)(phosphine)Cl]PF6 were studied.
These compounds in which the ferrocenyl and RuCn (n
) 1) moieties are separated by the methylene group
have not been studied yet. Generally, there are two
simple ways to prepare ruthenium(II)-ferrocene oligo-
metallic complexes of this type: (a) coordination of the
ferrocenyl moiety containing phosphines to ruthenium,
(b) transformation of terminal alkynes bearing the
ferrocenyl group to carbene complexes. The phosphine
complexes can be obtained by a reaction of the [(η6-
arene)RuCl2]2 dimer and the corresponding phosphine.
As for the preparation of carbene complexes, it has been
shown that the reaction of the arene-ruthenium(II)
complexes7 [(η6-arene)RuCl2(PR3)] with terminal alkynes
and NaPF6 in alcohols directly affords alkoxycarbenes
under mild conditions.8,9 The mechanism of the arene-
ruthenium(II) carbene formation involves the formation
of [LnRu(η2-HCtCR)] followed by the σ-π rearrange-
ment, yielding an unstable σ-vinylidene complex
[LnRudCdCHR].10,11 Formation of the alkoxycarbene
then proceeds by addition of alcohol to the electrophilic
Incorporating the redox-active ferrocenyl group(s) into
an organometallic compound results in the formation
of polymetallic species. Apart from being studied as the
communicating redox systems,1 such compounds exhibit
unusual electrochemical activation of some molecules.2
The conjugated ferrocene derivatives are being tested
for second-3 and third-order4 optical nonlinearity with
the aim of potential application in optical data storage
and processing. The use of ferrocenyl ligands in organic
synthesis and enantioselective catalysis is also well-
documented.5
As described previously,6 the presence of the ferro-
cenyl group in an arene-ruthenium(II) ferrocenyl-
(phenyl)allenylidene complex leads to mesomeric sta-
bilization of this compound. In order to evaluate the
mutual modification of the RuII/RuIII and the ferro-
* Author to whom correspondence should be addressed. E-mail:
stepnic@mail.natur.cuni.cz.
X Abstract published in Advance ACS Abstracts, October 15, 1997.
(1) Sato, M.; Hayashi, Y.; Kumakura, S.; Shimizu, N.; Katada, M.;
Kawata, S. Organometallics 1996, 15, 721 and references therein.
(2) Beer, P. D.; Kocian, O.; Mortimer, R. J . J . Chem. Soc., Dalton.
Trans. 1990, 3283.
(3) (a) Calabrese, J . C.; Cheng, L.-T.; Green, J . C.; Marder, S. R.;
Tam, W. J . Am. Chem. Soc. 1991, 113, 7227 and references therein.
(b) Bunting, H. E.; Green, M. L. H.; Marder, S. R.; Thompson, M. E.;
Bloor, D.; Kolinsky, P. V.; J ones, R. J . Polyhedron 1992, 11, 1489 and
references therein.
(4) Ghosal, S.; Samoc, M.; Prasad, P. N.; Tufariello, J . J . J . Phys.
Chem. 1990, 94, 2847.
(7) For a review of the reactivity of arene-ruthenium compounds,
see: Le Bozec, H.; Touchard, D.; Dixneuf, P. H. Adv. Organomet. Chem.
1989, 29, 163.
(8) (a) Le Bozec, H.; Ouzzine, K.; Dixneuf, P. H. Organometallics
1991, 10, 2768. (b) Ouzzine, K.; Le Bozec, H.; Dixneuf, P. H. J .
Organomet. Chem. 1986, 317, C25.
(5) For recent review, see: Ferrocenes; Togni, A., Hayashi, T., Eds.;
VCH: Weinheim, Germany, 1995.
(6) Pilette, D.; Ouzzine, K.; Le Bozec, H.; Dixneuf, P. H.; Rickard,
C. E. F.; Roper, W. R. Organometallics 1992, 11, 809.
(9) Devanne, D.; Dixneuf, P. H. J . Organomet. Chem. 1990, 390, 371.
(10) Bullock, R. M. J . Chem. Soc., Chem. Commun. 1989, 165.
(11) Silvestre, J .; Hoffmann, R. Helv. Chim. Acta 1985, 68, 1461
(theoretical study).
S0276-7333(97)00478-0 CCC: $14.00 © 1997 American Chemical Society

5090 Organometallics, Vol. 16, No. 23, 1997
Sˇ teˇpnicˇka et al.
Sch em e 1
vinylidene CR carbon. The lower stability of arene-
vinylidenes toward nucleophiles in comparison with
that of their isoelectronic Cp analogues [(η5-C5H5)-
Ru(dCdCHR′)(PR3)2]PF6 is the consequence of the
different electron-donating ability of the [(η6-arene)Ru-
(PR3)Cl]+ and [(η5-C5H5)Ru(PR3)2]+ moieties, as con-
firmed by the trends in the RuII/RuIII redox potentials
of [(η6-arene)RuCl2(PR3)] and [(η5-C5H5)RuCl(PR3)2].9
These studies show that the arene-ruthenium deriva-
tives are much more electron deficient than the analo-
gous Cp complexes. On the other hand, the high
reactivity of arene-ruthenium(II) vinylidenes can be
utilized for the activation of terminal alkynes. The
easily accessible complexes [(η6-arene)RuCl2(PR3)]
(arene ) p-cymene or hexamethylbenzene; PR3 ) PMe3
or PPh3) have been used as catalysts for regioselective
syntheses of enol esters,12 â-oxopropyl esters,13 and
â-oxoalkyl carbamates,14 for which analogous ruthe-
nium(II)-cyclopentadienyl derivatives were inactive.
Herein, we report the details of the synthesis and
spectral characterization of new (η6-hexamethylben-
zene)ruthenium(II) methoxycarbenes bearing ferrocenyl
unit(s) in the phosphine and/or carbene parts of mol-
ecule and also the properties of their parent (η6-
hexamethylbenzene)ruthenium(II) dichlorophosphine
complexes. We also describe the electrochemical be-
havior of these bimetallic and trimetallic complexes as
well as their fragmentation in liquid secondary mass
spectra and the crystal structure of [(η6-C6Me6)-
Ru(dC(OCH3)CH2Fc){((η5-C5H4PPh2)Fe(η5-C5H4COOH))-
P}(Cl)]PF6‚CH2Cl2 (4a ‚CH2Cl2).
larly, phosphorus NMR spectra taken at room temper-
ature exhibit the presence of one broad signal with
mutually similar coordination shift values: ∆P(3) ) 38.4
and ∆P(4) ) 37.8 (∆P ) δP(complex) - δP(free ligand);
δP(FcPPh2) ) -15.3, δP(Hdpf) ) -17.616 in C[2H]Cl3).
Respecting the steric requirements of the ferrocenyl
phosphines, such broadening of the NMR signals can
be attributed to a hindered intramolecular motion,
resulting in a dynamic equilibrium of conformers. The
temperature-dependent 31P{1H} NMR spectra of 3 in
C[2H]Cl3 solution revealed the presence of two isomers
in ca. 4:1 ratio with chemical shifts δP 21.5 and 27.4 at
223 K. When the sample is warmed, the signals
broaden to the coalescence point, which was found to
be within 263-273 K, followed by sharpening of the
Resu lts a n d Discu ssion
Syn th eses a n d Ch a r a cter iza tion . The starting
ferrocene-containing phosphine complexes [(η6-C6Me6)-
RuCl2(L)], where L ) FcPPh2 (3) and Hdpf (4; Hdpf )
(η5-C5H4PPh2)Fe(η5-C5H4COOH)), were prepared by the
cleavage of the chloro bridges in [(η6-C6Me6)RuCl2]2 on
addition of a stoichiometric amount of the corresponding
phosphine. These arene-ruthenium complexes and
their PMe3 (1) and PPh3 (2) analogues were then reacted
with terminal alkynes (FcCtCH (a ), Me3SiCtCH (b),
and PhCtCH (c)) in the presence of NaPF6 in MeOH/
CH2Cl2 to give the corresponding methoxycarbenes [(η6-
C6Me6)Ru(dC(OCH3)CH2R)Cl(L)]PF6 (L ) phosphine,
R ) Fc (1a , 2a , 3a , 4a ), H (3b, 4b), Ph (3c, 4c)) in good
yields (Scheme 1). For the preparation of (methoxy)-
methylcarbenes 3b and 4b, the general procedure was
used consisting of methanolysis of Si-C bonds in an
intermediate formed by the reaction of (trimethysilyl)-
acetylene.15 Although the solid benzyl and (ferrocenyl)-
methyl carbenes seem to be stable in air at room
temperature, their methyl analogues exhibit lower
stability, especially in solution. This is in accordance
with the predominantly steric stabilization of carbenes.
The composition and structure of the products were
determined by 1H and 31P{1H} NMR, infrared and mass
spectra, and elemental analyses. At room temperature,
1
single signal (δP 22.5 at 323 K). The H NMR spectra
of carbenes 2a -4c also exhibit broad lines (especially
these of the Cp and Ph protons), but no conformer
equilibria were observed. Because of the presence of
the chiral ruthenium center in carbenes 1a -4c, the
methylene protons in the proton NMR become dia-
stereotopic and remarkably anisochronic (the separation
of both signals of the AB system ∆δAB is up to 2.07 ppm
for 2a ). This relatively large separation could be
tentatively explained by the presence of strongly aniso-
tropically shielding phenyl and ferrocenyl17 groups in
the phosphine part of the molecules (compare with ∆δAB
0.65 for 1a ). In all cases, selective decoupling was used
to identify the low-field component of the AB system,
which often coincides with the broad and strong signals
of the Cp and methoxy protons. For 3a and 4a ,
anisochronicity of the R-protons of carbene cyclopenta-
dienyl was observed while the â-protons remain un-
resolved. Except for 1a , 13C NMR spectra of the
carbenes could not be obtained in sufficient quality due
to the broadening caused by intramolecular motion
which is slow in the NMR scale. Signals arising from
1
the H NMR spectra of 3 and 4 show relatively broad
lines of the cyclopentadienyl and phenyl protons. Simi-
(12) Ruppin, C.; Dixneuf, P. H. Tetrahedron Lett. 1986, 27, 6323.
(13) Devanne, D.; Dixneuf, P. H. J . Org. Chem. 1988, 53, 925.
(14) Bruneau, C.; Dixneuf, P. H. Tetrahedron Lett. 1987, 28, 2005.
(15) Parlier, A.; Rudler, H. J . Chem. Soc., Chem. Commun. 1986,
514.
(16) Podlaha, J .; Sˇteˇpnicˇka, P.; Ludv´ık, J .; C´ısarˇova´, I. Organo-
metallics 1996, 15, 543.
(17) Turbitt, T. D.; Watts, W. E. Tetrahedron 1972, 28, 1227.

(η6-Hexamethylbenzene)Ru(II) Methoxycarbenes
Ta ble 1. Cr ysta llogr a p h ic Da ta for 4a ‚CH2Cl2
Organometallics, Vol. 16, No. 23, 1997 5091
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 4a ‚CH2Cl2
formula
M
C49H53F6O3P2Cl3Fe2Ru
1184.97
Ru-C(C6Me6, av) 2.31(6)
C-C-C(C6Me6, av)
119(2)
cryst syst; space group
a (Å); R (deg)
b (Å); â (deg)
c (Å); γ (deg)
V (Å3); Z
triclinic; P1h (No. 2)
12.072(1); 104.11(1)
14.470(2); 99.663(8)
14.999(2); 93.773(9)
2489.3(5); 2
1.581
Car-Car(av)
Car-CH3(av)
1.41(2)
1.53(1)
Ru-Cl
2.390(3) Cl-Ru-C(61)
Cl-Ru-P(1)
93.2(4)
85.5(1)
87.0(3)
P(1)-Ru-C(61)
Dc (g‚mL-1
F(000)
)
Ru-C(61)
1.94(1)
1.30(1)
1.46(2)
1.52(2)
1.53(2)
1.38(4)
2.01(3)
O(3)-C(61)-C(63)
C(61)-O(3)-C(62)
C(61)-C(63)-C(71)
O(3)-C(61)-Ru
C(63)-C(61)-Ru
C(75)-C(71)-C(63)
C(72)-C(71)-C(63)
C-C-C(Fc, av)
117(1)
127(1)
114.4(9)
116.6(8)
126.3(9)
126(1)
1204
cryst size (mm3)
cryst description
0.05 × 0.2 × 0.3
orange-red plate
1.16
O(3)-C(61)
O(3)-C(62)
C(61)-C(63)
C(63)-C(71)
C-C(Fc, av)
Fe-C(av)
µ (mm-1
)
2θ range (deg)
2.8-46.0
hkl
+h, (k, (l
6941; 15.0
6910
no. of diffractions collected; R(σ)a
no. of unique diffractions
no. of obsd diffractions; Fo g 4σ(Fo)
standard diffractions
variation in standards (%)
127(1)
108(3)
3725
Ru-P(1)
2.343(3) C(21)-P(1)-Ru
112.5(4)
117.5(4)
115.3(3)
103.1(5)
105.9(5)
101.0(5)
123(1)
119(1)
118(1)
128(1)
126(1)
3 monitored every 1 h
2.9
0.0895, 8.6931
584
17.5, 6.9
20.8, 16.3
P(1)-C(21)
P(1)-C(41)
P(1)-C(51)
C(31)-C(36)
C(36)-O(1)
C(36)-O(2)
C-C(Fc, av)
Fe-C(av)
1.83(1)
1.82(1)
1.83(1)
1.46(2)
1.24(2)
1.29(2)
1.41(2)
2.04(2)
1.38(2)
C(41)-P(1)-Ru
C(51)-P(1)-Ru
b
weighting scheme: w1, w2
C(21)-P(1)-C(41)
C(21)-P(1)-C(51)
C(41)-P(1)-C(51)
O(1)-C(36)-O(2)
O(1)-C(36)-C(31)
O(2)-C(36)-C(31)
C(32)-C(31)-C(36)
C(35)-C(31)-C(36)
C-C-C(Fc, av)
no. of params
R
all(F), Robs(F)a (%)
wRall(F2), wRobs(F2)a (%)
a
GOFall
1.03
(∆/σ)max
0.000
1.11, -0.82
∆F (e‚Å-3
)
C-C(Ph, av)
a
2
R(F) ) ∑(||Fo| - |Fc||)/∑|Fo|, wR(F2) ) ∑[(w(Fo - Fc2)2)/
(w(Fo2)2]1/2, GOF ) [∑(w(Fo - Fc2)2)/(Ndiffrs - Nparams)]1/2, R(σ) )
2
108.0(9)
120(1)
∑σ(Fo2)/∑Fo
.
Weighting scheme: w ) [σ2(Fo2) + w1P2 + w2P]-1
;
2
b
C-C-C(Ph, av)
P ) [max(Fo2) + 2Fc2]/3.
P(2)-F(av)
1.47(6)
F-P(2)-Fcis(av)
90(4)
C(9A)-Cl(9A)
C(9A)-Cl(9B)
1.65(4)
1.79(4)
Cl(9A)-C(9A)-Cl(9B) 108(2)
the RudC(OCH3)CH2Fc moiety in the 13C{1H} NMR
spectrum of 1a were found within the expected region:8
RudC δC 320.7 (d, J PC ) 22 Hz), OCH3 δC 67.6, and
2
CH2 δC 50.2, as these clearly indicate the presence of
carbene. The assignment was supported by DEPT-135.
The decrease of electron density on changing the neutral
dichloro complex to the cationic carbene also results in
a significant downfield shift of the coordinated phos-
phine signal in the 31P{1H} NMR spectra. The coordi-
nation shift is practically independent of the nature of
the substituent R linked to the carbene part, as dem-
onstrated by the similarity of its value for 3a -c ∆P ≈
48 and 4a -c ∆P ≈ 50 (cf. ∆P(2a ) ) 39.8, δP(PPh3) ) -4.1
was obtained under the same conditions). These spec-
tral features are in agreement with the observed
electrochemical response of carbenes 1a -4c.
Cr ysta l Str u ctu r e. A single crystal X-ray diffraction
study of 4a ‚CH2Cl2 was carried out to confirm the solid-
state structure of carbenes. The crystallographic data
are given in Table 1 and the Experimental Section. A
listing of selected bond lengths and angles is given in
Table 2. As the hexafluorophosphate counterion and
solvating dichloromethane do not display any unexcep-
tional features, the organometallic cation is the only
interesting part of the present structure. The cation of
4a is chiral due to the presence of four different
substituents in a three-legged piano-stool structure; the
(RRu )-[(η6-C6Me6)Ru (dC(OCH 3)CH 2F c){((η5-C5H 4-
PPh2)Fe(η5-C5H4COOH))-P}(Cl)]+ enantiomer was ar-
bitrarily chosen in the refinement (Figure 1, PLA-
TON9218). In the racemic crystal, both enantiomeric
cations are joined through double centrosymmetric
hydrogen bonds: O(2)‚‚‚O(1)i 2.58(2) Å, i ) -x, -y, 1 -
z which are, however, distorted by the presence of the
neighboring dichloromethane molecule: O(2)‚‚‚Cl(9A)i
3.44(2) Å, O(1)‚‚‚Cl(9A) 4.07(2) Å. There are no further
significant intermolecular contacts except those at the
F igu r e 1. PLATON plot of the molecule (RRu )-4a ‚CH2Cl2
at the 30% probability level. The PF6- anion, the solvating
dichloromethane molecule, and all hydrogens are omitted.
van der Waals level. In the molecular structure of the
cation, the η6-hexamethylbenzene ring and the mono-
dentate ligands are mutually staggered and the η6-arene
ring is bent about the C(02)-C(05) axis; the dihedral
angle of the half planes defined by C(02), C(03), C(04),
C(05) and C(05), C(06), C(01), C(02), respectively, is to
8.5(8)°. A similar feature was observed for [(η6-C6H6)-
RuCl2(PMePh2)] and [(η6-p-MeC6H4CHMe2)RuCl2-
(PMePh2)].19 The length of the Ru-Cl bond is close to
the mean value found for Ru complexes (2.42(5) Å, 115
structures20) and the Ru-P bond length similar to that
of Ru-PPh2Me (2.40(6) Å, 4 structures; cf. Ru-PPh3
2.37(4) Å, 59 structures; Ru-PMe3 2.31(5) Å, 65 struc-
tures). The carbene RudC bond (1.94(1) Å) is slightly
(19) Bennett, M. A.; Robertson, G. B.; Smith, A. K. J . Organomet.
Chem. 1972, 43, C41.
(20) Orpen, A. G.; Brammer, L.; Allen, F. H.; Kennard, O.; Watson,
D. G.; Taylor, R. J . Chem. Soc., Dalton Trans. 1989, S1.
(18) Spek, A. L. Acta Crystallogr. 1990, A46, C34.

5092 Organometallics, Vol. 16, No. 23, 1997
Sˇ teˇpnicˇka et al.
appearance of the additional wave of the Fc/Fc+ couple,
strongly modifies the properties of both electrochemi-
cally active parts of the complex. First, the presence of
ferrocenyl phosphine causes a relative increase of the
RuII/RuIII potential and, simultaneously, the decrease
of the ferrocene/ferrocenium potential. For illustration,
EFc(FcPPh2) ) 0.11 V with ∆Ep ) 80 mV and (ipa/ipc) ≈
0.4 at the same conditions; for Hdpf, only the anodic
peak potential could be detected at the scan rate of 1
Ta ble 3. Red ox P oten tia ls of Ru th en iu m
a
Com p lexes in CH2Cl2
EFc [V]
compound
Fc/Fc+
RuII/RuIII
1
2
3
4
0.39
0.48
0.66
0.68
0.03(P)b
0.28(P)
1a
2a
3a
3b
3c
4a
4b
4c
0.08(C)
0.09(C)
0.05(C), 0.27(P)
0.22(P)
0.27(P)
0.06(C), 0.52(P)
0.45(P)
0.50(P)
0.90
1.12
1.08
1.07
1.15
1.12
1.09
1.16
Fc
V‚s-1, Epa ) 0.39 V. Second, there is an apparent
contradiction with the expected trend, i.e., the decrease
of the electron density in the ligand moiety on dative
bond formation, which causes an increase of the poten-
tial of the ligand-centered redox process. This common
trend could be illustrated by the potentials of the
following (diphenylphosphino)ferrocene complexes:
[(FcPPh2)M(CO)5], M ) Mo EFc ) 0.27 V; W EFc ) 0.29
V; while for noncoordinated FcPPh2, EFc ) 0.11 V.23
Such an unexpected electrochemical response for 3 and
4 could be attributed to a significant contribution of the
Ru r P π-back-donation, resulting in a decrease of the
electron-withdrawing properties of the diphenylphos-
phino group and, in this way, relative increase of the
electron density within the ferrocenyl moiety. At a
higher potential, the ferrocenium formed in the first
oxidative step undergoes a successive ruthenium-
centered oxidation. However, the presence of the strongly
electron-withdrawing ferrocenium makes this step more
difficult in comparison with simple phosphines contain-
ing complexes 1 and 2, as indicated by the shift to higher
potentials. Thus, by modification of the phosphine
substituent, the RuII/RuIII potential shifted to a higher
value although, taking into account the electron-donat-
ing ability of the ferrocenyl group, the potential could
be a priori expected between those of 1 and 2. The
coordination also stabilizes both ferrocenyl phosphines
toward subsequent reactions16 of the ferricinum species
yielding phosphine oxides. While free ferrocenyl phos-
phines exhibit quasi-reversible waves reflecting the
subsequent decomposition of the generated ferrocenium,
the values of (ipa/ipc) ≈ 1 observed for the phosphine-
centered redox step indicate reversible ferrocene-
ferrocenium processes in the case of 3, 4, 3a -c, and 4a -
c. An analogous stabilization has been reported for
(diphenylphosphino)ferrocene complexes of molybdenum
and tungsten (vide infra). Similarly, when not stabi-
lized by the formation of stable complexes such as
a
All observed redox processes exhibit a peak separation ∆Ep
in the range of 75-95 mV and (ipa/ipc) values of unity. Potentials
are given relative to ferrocene/ferrocenium, EFc
)
1/2(Epa + Epc).
Derivative cyclic voltammetry was used for Ep and ip determina-
tion. For further experimental details, see Experimental Section.
P and C denotes the ferrocenyl group in the phosphine and
carbene parts of molecule, respectively.
b
shortened in comparison with that of the vinylidene21
complex [(η6-C6Me6)Ru(dC(OCH3)CHdCPh2)(Me3P)Cl]-
PF6 (1.98 Å) because of the absence of conjugation. The
carbene moiety is planar [τ(C(62)-O(3)-C(61)-C(63))
) -1(2)°] without any significant difference from the
average bond lengths reported for carbenes of the
[LnRudC(OC′)C′′] type (C-C′′ 1.50(3) Å, C-O 1.32(2)
Å, O-C′ 1.47(2) Å; 18 structures20). The carbene
ferrocenyl does not show any deformation (the dihedral
angle of the least-squares Cp planes 4(2)°) apart from
a slight dynamic disorder of the unsubstituted Cp ring
along the D5 axis. The general geometry of carboxy-
phosphine ferrocenyl remains practically unaffected by
coordination (the dihedral angle of Cp ring planes
5.6(9)°, C-P-C angles similar to those of noncoordi-
nated Hdpf16). The only significant difference is the
relative conformation of the carboxy and diphenyl-
phosphino groups, which are anti-eclipsed with the
torsion angle τ(P(1)-CE(1)-CE(2)-C(36)) -148.1(5)°;
in contrast, noncoordinated Hdpf occupies a halfway
anti-conformation with the τ value of ca. -162°. As the
rotational barrier along the D5 axis is known to be low,
such changes are invoked most likely by crystal packing
effects, the H bond formation being one of the most
significant.
Electr och em istr y. For all compounds, the electro-
chemical study revealed that all observed redox proc-
esses are one-electron and reversible processes at the
scan rate of 1 V‚s-1, as indicated by the (ipa/ipc) ratios
of unity and the ∆Ep peak separations in the range of
75-95 mV. The redox potentials EFc given relative to
ferrocene/ferrocenium22 are summarized in Table 3. The
cyclic voltammograms of the starting chloro complexes
1 and 2 display only one wave from the RuII/RuIII redox
couple. The easier oxidation of 1 in comparison to 2 is
in accordance with the higher electron-donating ability
of the PMe3 ligand. The presence of ferrocenyl-bearing
phosphines in complexes 3 and 4, reflected by the
[M(dppf-P,P′)Cl2],
M
) Pd, Pt,24 free 1,1′-bis(di-
phenylphosphino)ferrocene (dppf) is oxidized to ferro-
cenium and immediately converted to protonated and
higher oxidized species.25
The change of the electrochemical response of the
carbene complexes in comparison to the neutral parent
chloro complexes is consistent with generation of cat-
ionic species (Figure 2). The electron density decrease
makes oxidation of RuII markedly more difficult, as
documented by the positive shift of about 0.5 V for the
ruthenium-centered oxidation. This change also affects
the phosphine part of the molecule, as manifested by
the anodic shift of approximately +0.2 V for the Fc/Fc+
(21) Structure VOYDOC in Cambridge Crystallographic Data Cen-
tre; for reference see: Allen, F. H.; Kennard, O. Chem. Design Automat.
News 1993, 8, 1, 31-37.
(23) Kotz, J . C.; Nivert, C. L.; Lieber, J . M.; Reed, R. C. J .
Organomet. Chem. 1975, 91, 87.
(24) Corain, B.; Longato, B.; Favero, G.; Ajo´, D.; Pilloni, G.; Russo,
U.; Kreissl, F. R. Inorg. Chim. Acta 1989, 157, 259.
(25) Pilloni, G.; Longato, B.; Corain, B. J . Organomet. Chem. 1991,
420, 57.
(22) ESCE ) EFc + ESCE(FcH/FcH+); ESCE(FcH/FcH+) ) +0.46 V in
CH2Cl2, 0.1 M BuN4PF6. For ref, see: Connelly, N. G.; Geiger, W. E.
Chem. Rev. 1996, 96, 877.

(η6-Hexamethylbenzene)Ru(II) Methoxycarbenes
Organometallics, Vol. 16, No. 23, 1997 5093
a
Ta ble 4. Ma ss Sp ectr om etr ic Ch a r a cter istics of Ca r ben es [(η6-HMB)Ru (dC(OCH3)CH2R)(L)Cl]P F 6
1a
2a
3a
3b
3c
4a
4b
4c
compound (L/R)
(PMe3/Fc) (PPh3/Fc) (FcPPh2/Fc) (FcPPh2/H) (FcPPh2/Ph) (Hdpf/Fc) (Hdpf/H) (Hdpf/Ph)
[cation]+
617(100) 803(17)
911(100)
875(2)
713(22)
669(10)
633(6)
541(42)
505(10)
370(97)
569(29)
593(45)
727(11)
weak
803(100)
767(3)
605(10)
669(3)
955(79)
weak
757(21)
713(6)
677(40)
541(100) 357(12)
505(29)
414(29)
771(7)
847(94)
811(3)
649(42)
713(3)
677(16)
433(100)
397(51)
[cation - HCl]+
581(2)
weak
[cation - HMB - HCl]+
[cation - C(OCH3)CH2R]+
[cation - C(OCH3)CH2R - HCl]+
[cation - L]+
419(11)
375(40)
<350
541(3)
605(8)
561(9)
525(13)
541(9)
505(6)
<350
669(12)
633(3)
357(14)
weak
713(26)
677(46)
633(3)
433(48)
397(18)
370(81)
[cation - L - HCl]+
321(22)
414(100) 414(35)
L+
<350
370(100)
[LCH2R]+
<350
<350
461(100)
485(16)
[cation - CpFe - HMB - Cl]+
[cation - C6H5O2Fe - HMB - Cl]+
[cation - CpFe - C(OCH3)CH2R - HCl]+
[cation - C6H5O2Fe - C(OCH3)CH2R - HCl]+
other
weak
485(19)
513(8)
637(25)
593(14)
485(24)
<350
<350
513(18)
513(12)
513(21)
887(22)c
513(54)
513(14)
779(8)c
641(8)b
a
LSIMS data obtained in a 3-nitrobenzyl alcohol matrix. The signals with m/ z > 350 only are listed as m/ z(relative intensity). HMB
) hexamethylbenzene, L ) phosphine. [cation - HMB]+. c [cation - 68]+, possible elimination of HCl and MeOH.
b
ion mass spectra of the complexed salts 1a , 2a , 3a -c,
and 4a -c exclusively exhibit the signals of the free
organometallic cations and their fragment ions, most
likely owing to the dissociation of the ionic carbenes
dissolved in the matrix. Nevertheless, the presence of
the hexafluorophosphate counterion is obvious from the
presence of weak signals due to the formation of clusters
[cation2, PF6-]+. In general, the cations undergo frag-
mentation by splitting of ruthenium-bonded ligands, i.e.,
the carbene part, hexamethylbenzene, or phosphine,
together or without the elimination of HCl (Table 4).
While fragment ions corresponding to the loss of the
phosphine or carbene part with or without concurrent
elimination of HCl are easily observable; the peaks
corresponding to the loss of C6Me6 or HCl are weak or
not observed at all. On the other hand, the simulta-
neous loss of C6Me6 and HCl results in peaks of
considerable intensity, with the exception of methyl
carbenes 3b and 4b. All spectra also display the
F igu r e 2. Cyclic voltammetric response of 4 (broken line)
presence of positively charged free phosphines. In the
and 4a (full line). C, P, and Ru denote carbene ferrocenyl,
case of 2a and 3a , further peaks appear in the spectra
phosphine ferrocenyl, and ruthenium-centered redox proc-
which correspond to phosphonium ions resulting by the
esses, respectively (circled for 4a ).
migration of the carbene substituent (RCH2 in [LnRu-
(dC(OCH3)CH2R)]+) to phosphine phosphorus. It is
potential. This is most likely caused by an electron-
density transfer from phosphine to ruthenium, which
worth noting that the presence of the ferrocene skeleton
in all cases leads to the occurrence of less common ionic
cannot be compensated by back-donation from the now
electron-deficient metal. Similar trends in the Fc/Fc+
potential were observed in the case of the (diphenyl-
phosphino)ferrocene carbonyl complexes of molybdenum
and tungsten mentioned above, in which the contribu-
tion of the back-donation from the metal to phosphorus
could be expected to be weak due to the presence of five
good π-accepting carbonyl ligands. Moreover, replace-
ment of the electron-withdrawing ethynyl group by an
electron-donating alkyl returns the carbene Fc/Fc+
potential in 1a , 2a , 3a , and 4a to values close to those
of unsubstituted ferrocene (cf. FcCtCH EFc ) 0.16 V,
∆Ep ) 75 mV, ipa/ipc ) 1.0 under the same conditions).
These potentials are practically unaffected by changes
on the metal center. Likewise, the RuII/RuIII potentials
exhibit only a small variation on changing the substitu-
ent in the carbene part, as indicated by the trends in
3a -c and 4a -c. These facts clearly imply an inter-
ruption of electronic communication, except for simple
inductive effects, between LnRudC and the carbene
substituent R (RudC(OCH3)CH2R) on introduction of
a CH2 spacer.
species in the spectra. Their formation involves elimi-
nation of cyclopentadienyl-iron ([C5H5Fe]+) or carboxy-
cyclopentadienyl-iron ([C6H5O2Fe]+) fragments arising
from phosphine or carbene ferrocenyls.
The mass spectra of dichloro complexes 3 and 4
exhibit positively charged molecular ions and fragments
[M - nCl]+ (n ) 1, 2). Although the loss of the
phosphine molecule has not been observed here, the
charged phosphines, [FcPPh2]+ and [Hdpf]+, appear as
the most intense peaks in the spectra (for low-resolution
mass spectral data, see Experimental Section).
A
further notable feature similar to that in the carbenes
is the presence of the ionic species m/ z 513 due to the
simultaneous loss of two chlorine atoms and [C5H5Fe]+
and [C6H5O2Fe]+ for 3 and 4.
Con clu d in g Rem a r k s
We described the syntheses of several new ferrocenyl-
substituted ruthenium(II) carbenes. These compounds
were studied with respect to their structure and elec-
tronic properties by multinuclear NMR spectroscopy and
Ma ss Sp ectr om etr y. The positive-mode secondary

5094 Organometallics, Vol. 16, No. 23, 1997
Sˇ teˇpnicˇka et al.
H, C5H4), 4.56 (br s, 2 H, C5H4), 7.34-7.46 (m, 6 H, PPh2),
7.85-8.01 (m, 4 H, PPh2). 31P{1H} NMR (C[2H]Cl3): δ 22.3
(br s). IR (cm-1): ν(CH) 3049 (w), 2908 (w); δs(CH3) 1383 (m);
Fc 1096 (m), 1002 (m); PPh2 470 (s, composed). Anal. Calcd
for C34H37PCl2FeRu: C, 57.97; H, 5.29; P, 4.40. Found: C,
58.07; H, 5.41 P, 4.20. HR LSIMS: m/ z [C34H37PCl2FeRu]+
(M+) calcd 704.0409, found 704.039; [C34H37PClFeRu]+ ([M -
Cl]+), calcd 669.0723, found 669.072. LSIMS: m/ z (relative
intensity) 704 (6, M+), 669 (25, [M - Cl]+), 633 (3, [M - 2Cl]+),
513 (15, [M - 2Cl - C5H5Fe]+), 370 (100, [FcPPh2]+).
electrochemistry in solution and by single-crystal X-ray
diffraction in the solid state. From the electrochemical
behavior of the ferrocenyl phosphines bearing (η6-hexa-
methylbenzene)chlororuthenium(II) methoxycarbenes
and their parent (η6-hexamethylbenzene)dichlororu-
thenium(II) complexes, it follows that there is no
electronic communication between the LnRudC moiety
and the carbene substituent, excluding inductive effects.
On the other hand, the presence of the oxidized phos-
phine ligand (formation of P-coordinated ferrocenium
precedes the RuII f RuIII oxidation) results in a signifi-
cant electron density lowering at the central atom. Such
a modification of the electronic properties of the metal
center in catalytically important organometallic com-
pounds by changing the oxidation state of ligand(s)
might be used for fine “tuning” their catalytic properties.
[(η6-C6Me6)Ru (Hd p f-P )Cl2] (4). Starting from [(η6-C6Me6)-
Ru(µ-Cl)Cl]2 (0.667 g, 1.00 mmol) and Hdpf (0.829 g, 2.00
mmol), the same procedure as for 3 yielded 4 (1.470 g, 98%)
as an orange-red solid. 1H NMR (C[2H]Cl3): δ 1.75 (s, 18 H,
C6Me6), 3.74 (s, 2 H, C5H4), 4.50 (s, 4 H, C5H4), 4.60 (s, 2 H,
C5H4), 7.33-7.52 (br s, 6 H, PPh2), 7.78-7.98 (br s, 4 H, PPh2).
31P{1H} NMR (C[2H]Cl3): δ 20.2 (br s). IR (cm-1): ν(CH) 3050
(w), 2982 (w); ν(CdO) 1712 (m), 1686 (s); δs(CH3) 1385 (m); Fc
1096 (m), 1035 (m); PPh2 490 (s, composed). Anal. Calcd for
C
35H37O2PCl2FeRu: C, 56.17; H, 4.98; P, 4.14. Found: C,
Exp er im en ta l Section
55.89; H, 4.90; P, 4.01. HR LSIMS: m/ z [C35H37O2PCl2FeRu]+
(M+) calcd 748.0308, found 748.032; [C35H37O2PClFeRu]+ ([M
- Cl]+), calcd 713.0621, found 713.060. LSIMS: m/ z (relative
intensity) 748 (6, M+), 713 (35, [M - Cl]+), 677 (66, [M - 2Cl]+),
513 (15, [M - 2Cl - C6H5O2Fe]+), 414 (100, [Hdpf]+).
Gen er a l Con sid er a tion s. All experiments were carried
out in an atmosphere of argon or nitrogen using Schlenk
techniques. The solvents were dried and deoxygenated by
standard procedures. 1H (200.13 MHz), 31P{1H} (81.02 MHz),
and 13C{1H} (50.33 MHz) NMR spectra were recorded on a
Bruker DPX200 spectrometer at 296 K with external tetra-
methylsilane (1H, 13C) and external 85% aqueous H3PO4 (31P)
as the standards. Liquid secondary-ion mass spectral (LSIMS)
data were obtained on a VG ZabSpec spectrometer (CRMPO
center, University of Rennes) operating in a positive-ion mode
using CsI as the primary ion source and 3-nitrobenzyl alcohol
as the matrix. For high-resolution measurements (HRMS),
poly(ethylene glycol) was used as the mass scale calibrant. IR
spectra were recorded on a Nicolet 205 spectrometer in KBr
pellets. Cyclic voltammograms were measured in an argon
atmosphere with 1 × 10-3 M dichloromethane solutions
containing 0.1 M Bu4NPF6 as the supporting electrolyte at the
scan rate of 1 V‚s-1. The measurements were carried out using
a potentiostat (model 263, EG&G Princeton Applied Research)
connected to an oscilloscope (Nicolet 310), a wave form
generator (Hewlett-Packard 33120A), and a selective amplifier
(model 189, EG&G Princeton Applied Research) with platinum
discs of 0.4 mm diameter as the working and auxiliary
electrodes and a saturated calomel electrode as the reference.
The potentials are given relative to ferrocene/ferrocenium; a
calibration cyclic voltammogram of ferrocene was registered
before each measurement. Elementary analyses were per-
formed by the CNRS Service Central d’Analyses (Vernaison,
France). [(η6-C6Me6)Ru(µ-Cl)Cl]2,26 [(η6-C6Me6)Ru(L)Cl2]27 (L
) PMe3 (1), PPh3 (2)), FcCtCH,28 FcPPh2,29 and Hdpf16 were
prepared according to the published procedures.
Gen er a l P r oced u r e for P r ep a r a tion of Ca r ben es. The
starting ruthenium(II) complex [(η6-C6Me6)RuCl2(phosphine)]
(0.5 mmol) and NaPF6 (0.5 mmol or slight excess) were
dissolved in methanol (25 mL) and dichloromethane (25 mL;
except for 1a ), and an excess of alkyne was added. The
mixture was stirred at room temperature for 90 min (the
progress of reaction causes color lightening), and the resulting
solution was evaporated under reduced pressure. After the
solid was washed with diethyl ether (3 × 20 mL; removal of
unreacted alkyne) and dried in vacuo, the solid residue was
dissolved in dichloromethane (10 mL) and the solution filtered
via cannula to remove NaCl. After addition of pentane (40
mL) to the filtrate, the biphasic mixture was left to crystallize
on diffusion at -20 °C for several days. Decantation of the
solvent mixture followed by washing with pentane (20 mL)
and drying in vacuo afforded solid carbenes.
[(η6-C6Me6)Ru (dC(OCH3)CH2Fc)(P Me3)(Cl)] (1a). 1 (206
mg, 0.50 mmol), NaPF6 (86 mg, 0.51 mmol) and FcCtCH (316
mg, 1.50 mmol) gave 1a (310 mg, 81%) as ruby-red crystals.
The reaction was carried out in methanol (25 mL) without
addition of dichloromethane. 1H NMR (C[2H]Cl3): δ 1.47 (d,
2J PH ) 10.6 Hz, 9 H, PMe3), 2.04 (s, 18 H, C6Me6), 4.20 (br m,
2
2 H, C5H4), 4.22 (d, J HH ) 12.6 Hz, 1 H, AB CH2), 4.23 (s, 5
2
H, C5H5), 4.31 (s, 2 H, C5H4), 4.69 (s, 3 H, OMe), 4.87 (d, J HH
) 12.6 Hz, 1 H, AB CH2). 31P{1H} NMR (C[2H]Cl3): δ -143.1
(sept, 1J PF ) 712 Hz, PF6-), 9.1 (s, PMe3). 13C{1H} NMR (C[2H]-
1
Cl3): δ 16.2 (d, J PC ) 34 Hz, PMe3), 16.8 (s, C6Me6), 50.2 (s,
P r ep a r a t ion of (η6-Hexa m et h ylb en zen e)R u Cl2(p h os-
p h in e) Com p lexes, [(η6-C6Me6)Ru (F cP P h 2)Cl2] (3). To a
stirred solution of [(η6-C6Me6)Ru(µ-Cl)Cl]2 (0.667 g, 1.00 mmol)
in dichloromethane (50 mL), FcPPh2 (0.750 g, 2.03 mmol) was
added in one portion and the mixture was stirred for 90 min
at room temperature. After evaporation under reduced pres-
sure, the product was washed with diethyl ether (25 mL) and
pentane (2 × 25 mL) and dried in vacuo to give 3 (1.283 g,
91%) as an orange-red solid. 1H NMR (C[2H]Cl3): δ 1.75 (d,
4J PH ) 0.5 Hz, 18 H, C6Me6), 3.78 (s, 5 H, C5H5), 4.42 (br s, 2
2
CH2), 67.6 (s, OMe), 68.9 (d, J PC ) 31 Hz, C5H4, CR), 70.1 (s,
1
C5H5), 72.2 (s, C5H4, Câ), 78.5 (d, J PC ) 86 Hz, C5H4, Cipso),
2
2
107.6 (d, J PC ) 2 Hz, C6Me6), 320.7 (d, J PC ) 22 Hz, RudC).
IR (cm-1): ν(CH) 3094 (w), 2920 (w); δs(CH3) 1385 (m); ν(C-
-
O) 1275 (s); Fc 1052 (m), 954 (m); PF6 839 (s); PPh2 482 (s).
Anal. Calcd for C28H41OF6P2ClFeRu: C, 44.14; H, 5.42; P,
8.13. Found: C, 44.64; H, 5.40; P, 7.87. HR LSIMS: m/ z
[C28H41OPClFeRu]+ ([M - PF6]+), calcd 617.0983, found 617.095.
[(η6-C6Me6)Ru (dC(OCH3)CH2F c)(P P h 3)(Cl)] (2a ). 2 (299
mg, 0.50 mmol), NaPF6 (86 mg, 0.51 mmol) and FcCtCH (210
mg, 1.00 mmol) gave 2a (422 mg, 89%) as rusty-brown needles.
2
(26) Bennett, M. A.; Huang, T.-N.; Matheson, T. W.; Smith, A. K.;
Ittel, S.; Nickerson, W. Inorg. Synth. 1982, 21, 74.
(27) For general procedure, see: (a) Zelonka, R. A.; Baird, M. C.
Can. J . Chem. 1972, 50, 3063. (b) Bennett, M. A.; Smith, A. K. J . Chem.
Soc., Dalton Trans. 1974, 233.
(28) (a) Rosenblum, M.; Brawn, N.; Papenmeier, J .; Applebaum, M.
J . Organomet. Chem. 1966, 6, 173. (b) Rosenblum, M.; Brawn, N.;
Ciappenelli, D.; Tancrede, J . J . Organomet. Chem. 1970, 24, 469.
(29) (a) Sollott, G. P.; Mertwoy, H. E.; Portnoy, S.; Snead, J . L. J .
Org. Chem. 1963, 28, 1090. (b) Kotz, J . C.; Nivert, C. L. J . Organomet.
Chem. 1973, 52, 387.
1H NMR (C[2H]Cl3): δ 1.76 (s, 18 H, C6Me6), 2.37 (d, J HH
)
12.3 Hz, 1 H, AB CH2), 4.01 (s, 5 H, C5H5), 4.12 (m, 2 H, C5H4,
Hâ), 4.14 (m, 1 H, C5H4, HR), 4.44 (d, J HH ) 12.3 Hz, 1 H, AB
CH2), 4.65 (m, 1 H, C5H4, HR), 4.66 (s, 3 H, OMe), 7.46-7.62
(m, 15 H, PPh3). 31P{1H} NMR (C[2H]Cl3): δ -143.0 (sept,
1J PF ) 712 Hz, PF6-), 35.7 (s, PPh3). IR (cm-1): ν(CH) 3056
(w), 2923 (w); δs(CH3) 1385 (m); ν(C-O) 1287 (s); Fc 1095 (m),
2
-
1002 (m); PF6 839 (s); PPh3 491-558 (composed s). Anal.
Calcd for C43H47OF6P2ClFeRu: C, 54.47; H, 4.00. Found: C,

(η6-Hexamethylbenzene)Ru(II) Methoxycarbenes
Organometallics, Vol. 16, No. 23, 1997 5095
54.26; H, 4.28. HR LSIMS: m/ z [C43H47OPClFeRu]+ ([M -
PF6]+), calcd 803.1457, found 803.145.
4.84 (br s, 2 H, C5H4), 7.48-7.82 (br m, 10 H, PPh2). 31P{1H}
NMR (C[2H]2Cl2): δ -143.2 (sept, J PF ) 711 Hz, PF6-), 32.3
1
[(η6-C6Me6)Ru (dC(OCH3)CH2F c)(P P h 2F c)(Cl)] (3a ). 3
(353 mg, 0.50 mmol), NaPF6 (84 mg, 0.50 mmol), and FcCtCH
(br s, Hdpf). IR (cm-1): ν(CH) 3055 (w), 2918 (w); ν(CdO) 1712
(s), 1671 (s); δs(CH3) 1385 (m); ν(C-O) 1292 (s); Fc 1096 (m),
1070 (m), 1030 (m); PF6- 840 (s); PPh2 483 (composed m). HR
LSIMS: m/ z [C38H43O3PClFeRu]+ ([M - PF6]+) calcd 771.1041,
found 771.103. For the instability of this compound at ambient
conditions, no relevant microanalytical data could be obtained.
(212 mg, 1.01 mmol) gave 3a (439 mg, 83%) as a brown solid.
2
1H NMR (C[2H]Cl3): δ 1.74 (s, 18 H, C6Me6), 2.21 (d, J HH
)
12.6 Hz, 1 H, AB CH2), 4.00 (s, 10 H, C5H5), 4.03 (d, 1 H, AB
CH2, identified by selective decoupling), 4.05 (br m, 2 H, C5H4),
4.10 (m, 2 H, C5H4), 4.63 (s, 3 H, OMe), 4.47-4.82 (br m, 4 H,
C5H4), 7.54-8.02 (br m, 10 H, PPh2). 31P{1H} NMR (C[2H]Cl3):
[(η6-C6Me6)Ru (dC(OCH3)CH2P h )(Hd p f-P )(Cl)] (4c).
4
(374 mg, 0.50 mmol), NaPF6 (86 mg, 0.51 mmol), and PhCtCH
(0.15 mL, 1.4 mmol) gave 4c (424 mg, 86%) as a rusty-orange
solid. 1H NMR (C[2H]Cl3): δ 1.77 (s, 18 H, C6Me6), 2.52 (d,
2J HH ) 13.3 Hz, 1 H, AB CH2), 3.99 (s, 2 H, C5H4), 4.11 (s, 2
H, C5H4), 4.52 (s, 3 H, OMe), 4.66 (br s, 2 H, C5H4), 4.73 (s, 2
H, C5H4), 7.00-7.11 (m, 2 H, CH2Ph), 7.21-7.30 (m, 3 H,
CH2Ph), 7.58-8.11 (br m, 10 H, PPh2). 31P{1H} NMR (C[2H]-
δ -143.0 (sept, J PF ) 712 Hz, PF6-), 32.5 (s, PPh2Fc). IR
1
(cm-1): ν(CH) 3092 (w), 2922 (w); δs(CH3) 1386 (m); ν(C-O)
-
1299, 1262 (s); Fc 1110 (m), 1003 (m); PF6 840 (s); PPh2 491
(s), 475 (s). Anal. Calcd for C47H51OF6P2ClFe2Ru: C, 53.45;
H, 4.87; P, 5.87. Found: C, 53.02; H, 4.86; P, 5.74. HR
LSIMS: m/ z [C47H51OPClFe2Ru]+ ([M - PF6]+) calcd 911.1123,
found 911.114.
Cl3): δ -143.1 (sept, J PF ) 712 Hz, PF6-), 31.9 (s, Hdpf). IR
1
[(η6-C6Me6)Ru (dC(OCH3)CH3)(P P h 2Fc)(Cl)] (3b). 3 (354
mg, 0.50 mmol), NaPF6 (86 mg, 0.51 mmol), and Me3SiCtCH
(0.20 mL, 1.4 mmol) gave 3b (298 mg, 68%) as a rusty-orange
solid. 1H NMR (C[2H]2Cl2): δ 1.87 (s, 18 H, C6Me6), 2.25 (br
s, 3 H, RudCCH3), 4.00 (s, 5 H, C5H5), 4.37 (s, 3 H, OMe),
4.55 (br s, 2 H, C5H4), 4.66 (br s, 2 H, C5H4), 7.46-7.98 (br m,
(cm-1): ν(CH) 3090 (w), 2920 (w); ν(CdO) 1716 (s), 1678 (s);
δs(CH3) 1386 (m); ν(C-O) 1263 (s), 1301 (s); Fc 1097 (m), 1037
(s), 1003 (m); PF6- 840 (s); PPh2 483 (composed s). Anal. Calcd
for C44H47O3F6P2ClFeRu: C, 53.27; H, 4.77; P, 6.24. Found:
C, 52.88; H, 4.86; P, 6.24. HR LSIMS: m/ z [C44H47O3-
PClFeRu]+ ([M - PF6]+) calcd 847.1356, found 847.135.
St r u ct u r e Det er m in a t ion . Thin, plate-like and fragile
crystals of 4a ‚CH2Cl2 were grown by gas-phase diffusion of
pentane into a dichloromethane solution of 4a . They were
isolated by decantation and mounted on a glass fiber by epoxy
cement. The diffractions were measured at 296(1) K on an
Enraf-Nonius CAD 4-MACH III diffractometer using graphite-
monochromated Mo KR radiation (λ ) 0.710 73 Å) and θ-2θ
scan. Intensities were collected at ψ-angles with the lowest
absorption predicted. No further correction for absorption was
made. The cell parameters were determined by least-squares
from 25 centered diffractions with 12.0 e θ e 12.8°.
1
10 H, PPh2). 31P{1H} NMR (C[2H]2Cl2): δ -143.2 (sept, J PF
) 711 Hz, PF6-), 32.8 (br s, PPh2Fc). IR (cm-1): ν(CH) 3048
(w), 2915 (w); δs(CH3) 1385 (m); ν(C-O) 1282 (m); Fc 1098 (m),
-
1001 (m); PF6 839 (s); PPh2 473-518 (s, composed). HR
LSIMS: m/ z [C37H43OPClFeRu]+ ([M - PF6]+) calcd 727.1142,
found 727.114. The instability of the compound at ambient
conditions did not permit us to obtain correct microanalytical
results.
[(η6-C6Me6)Ru (dC(OCH3)CH2P h )(P P h 2F c)(Cl)] (3c). 3
(355 mg, 0.50 mmol), NaPF6 (87 mg, 0.52 mmol), and PhCtCH
(0.15 mL, 1.4 mmol) gave 3c (412 mg, 86%) as a rusty-red
microcrystalline solid. 1H NMR (C[2H]Cl3): δ 1.77 (s, 18 H,
The structure was solved by direct methods (SIR9230),
followed by consecutive Fourier syntheses and refined by full-
matrix least-squares on F2 (SHELX9331). Non-hydrogen atoms
were refined anisotropically, except those of the solvate
dichloromethane. Aromatic (ferrocenyl, phenyl), methylene
(FcCH2, CH2Cl2), and methyl (C6Me6, OCH3) hydrogens were
fixed in theoretical positions to fit aromatic C-H (0.93 Å), ideal
methylene group (C-H 0.97 Å), or electron density maxima
(C-H 0.96 Å), respectively, with Uiso(H) ) 1.2 Ueq(C). The
carboxylic hydrogen was identified on a difference electron
density map and refined. The hexafluorophosphate anion and
dichloromethane are partly disordered due to high symmetry
or weak secondary bonding, respectively. The small crystal
volume and the presence of partly disordered moieties are
responsible for the higher values of the R indices.
2
C6Me6), 2.51 (d, J HH ) 13.2 Hz, 1 H, AB CH2), 3.92 (s, 1 H,
2
C5H4), 3.93 (s, 5 H, C5H5), 4.45 (s, 1 H, C5H4), 4.52 (d, J HH
)
13.2 Hz, 1 H, AB CH2), 4.53 (s, 3 H, OMe), 4.66 (s, 1 H, C5H4),
4.94 (br s, 1 H, C5H4), 7.01-7.11 (m, 2 H, CH2Ph), 7.21-7.31
(m, 3 H, CH2Ph), 7.55-8.11 (br m, 10 H, PPh2). 31P{1H} NMR
(C[2H]Cl3): δ -143.1 (sept, J PF ) 712 Hz, PF6-), 32.7 (s,
1
PPh2Fc). IR (cm-1): ν(CH) 3057 (w), 2924 (w); δs(CH3) 1386
-
(m); ν(C-O) 1301 (s), 1262 (s); Fc 1096 (m), 1003 (m); PF6
839 (s); PPh2 491 (s), 477 (s). Anal. Calcd for C43H47OF6P2-
ClFeRu: C, 54.47; H, 4.00; P, 6.53. Found: C, 54.26; H, 4.09;
P, 6.55. HR LSIMS: m/ z [C43H47OPClFeRu]+ ([M - PF6]+)
calcd 803.1457, found 803.144.
[(η6-C6Me6)Ru (dC(OCH3)CH2F c)(Hd p f-P )(Cl)] (4a ).
4
(375 mg, 0.50 mmol), NaPF6 (86 mg, 0.51 mmol), and FcCtCH
(210 mg, 1.00 mmol) gave 4a (479 mg, 87%) as brown needles.
2
1H NMR (C[2H]2Cl2): δ 1.73 (s, 18 H, C6Me6), 2.17 (d, J HH
)
Ack n ow led gm en t. This work was supported by the
Grant Agency of Charles University, the Grant Agency
of Czech Republic, and the CNRS. P.Sˇ. gratefully
acknowledges a fellowship in Rennes.
12.8 Hz, 1 H, AB CH2), 4.03 (s, 5 H, C5H5), 4.04 (d, 1 H, AB
CH2, identified by selective decoupling), 4.08 (s, 2 H, C5H4),
4.16 (s, 2 H, C5H4), 4.49 (s, 3 H, OMe), 4.42-4.82 (br m, 8 H,
C5H4), 7.35-8.15 (br m, 10 H, PPh2). 31P{1H} NMR (C[2H]2-
Cl2): δ -143.3 (sept, J PF ) 711 Hz, PF6-), 31.8 (br s, Hdpf).
1
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal-
lographic data, calculated and refined positional parameters,
anisotropic thermal parameters, and intramolecular distances
and angles and a packing diagram of 4a ‚CH2Cl2 (14 pages).
Ordering information is given on any current masthead page.
IR (cm-1): ν(CH) 3094 (w), 2925 (w); ν(CdO) 1719, 1677;
δs(CH3) 1386 (m); ν(C-O) 1292, 1270 (s); Fc 1096 (m), 1040
-
(s), 1002 (m); PF6 841 (s); PPh2 484 (s). Anal. Calcd for
48H51O3F6P2ClFe2Ru: C, 52.41; H, 4.67; P, 5.63. Found: C,
52.25; H, 4.65; P, 5.55. HR LSIMS: m/ z [C48H51O3PClFe2-
C
Ru]+ ([M - PF6]+) calcd 955.1022, found 955.103.
OM970478K
[(η6-C6Me6)Ru (dC(OCH3)CH3)(Hd p f-P )(Cl)] (4b). 4 (375
mg, 0.50 mmol), NaPF6 (86 mg, 0.51 mmol), and Me3SiCtCH
(0.20 mL, 1.4 mmol) gave 4b (342 mg, 75%) as a rusty-orange
solid. 1H NMR (C[2H]2Cl2): δ 1.85 (s, 18 H, C6Me6), 2.38 (br
s, 3 H, RudCCH3), 4.11 (br m, 2 H, C5H4), 4.33 (s, 2 H, C5H4),
4.53 (s, 3 H, OMe), 4.64 (br s, 1 H, C5H4), 4.70 (br s, 1 H, C5H4),
(30) Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, G.; Giaco-
vazzo, C.; Guagliardi, A.; Polidori, G. J . Appl. Crystallogr. 1994, 27,
435.
(31) Sheldrick, G. M. SHELXL93. Program for Crystal Structure
Refinement from Diffraction Data; University of Go¨ttingen: Go¨ttingen,
Germany, 1993.