Reaction of [CpRu(CH3CN)3]PF6 with bidentate ligands: Structural characterization of [{CpRu(CH3CN)2}2 (μ-η1:1-dppe)](PF6)2 [dppe=1,2-bis(diphenylphosphino)ethane]

Article abstract of DOI:10.1016/j.jorganchem.2004.02.035

The reaction of [CpRu(CH₃CN)₃]PF₆ with the bidentate ligands L-L=1,2-bis(diphenylphosphino)ethane, dppe, and (1-diphenylarsino-2-diphenylphosphino)ethane, dpadppe, affords mononuclear or dinuclear complexes of formula [CpRu(η²-L-L)(CH₃CN)]PF₆, [{CpRu(CH₃CN)₂}₂ (μ-η^1:1-L-L)](PF₆)₂ and [{CpRu(CH₃CN)}₂(μ-η^1:1-L-L) ₂](PF₆)₂ (L-L=dppe, dpadppe). All of the compounds are characterized by microanalysis and NMR [¹H and ³¹P{¹H}] spectroscopy. The crystal structure of [{CpRu(CH₃CN)₂}₂ (μ-η^1:1-dppe)](PF₆)₂ has been determined by X-ray diffraction analysis. The complex exhibits a dppe ligand bridging two CpRu(CH₃CN)₂ fragments.

Full text of DOI:10.1016/j.jorganchem.2004.02.035

Journal of Organometallic Chemistry 689 (2004) 1757–1762
www.elsevier.com/locate/jorganchem
Reaction of [CpRu(CH3CN)3]PF6 with bidentate ligands:
structural characterization of [{CpRu(CH3CN)2}2
(l-g1:1-dppe)](PF6)2 [dppe ¼ 1,2-bis(diphenylphosphino)ethane] q
Massimo Di Vaira , Stefano Seniori Costantini , Fabrizio Mani , Maurizio Peruzzini ,
a
a
a
b
a,
*
Piero Stoppioni
a
Dipartimento di Chimica, Universitꢀa di Firenze, via della Lastruccia n. 3, 50019 Sesto Fiorentino, Firenze, Italy
ICCOM CNR, via Madonna del Piano, 50019 Sesto Fiorentino, Firenze, Italy
b
Received 21 January 2004; accepted 24 February 2004
Abstract
The reaction of [CpRu(CH3CN)3]PF6 with the bidentate ligands L–L ¼ 1,2-bis(diphenylphosphino)ethane, dppe, and (1-diph-
enylarsino-2-diphenylphosphino)ethane, dpadppe, affords mononuclear or dinuclear complexes of formula [CpRu(g2-L–
L)(CH3CN)]PF6, [{CpRu(CH3CN)2}2(l-g1:1-L–L)](PF6)2 and [{CpRu(CH3CN)}2(l-g1:1-L–L)2](PF6)2 (L–L ¼ dppe, dpadppe). All
of the compounds are characterized by microanalysis and NMR [1H and 31P{1H}] spectroscopy. The crystal structure of
[{CpRu(CH3CN)2}2(l-g1:1-dppe)](PF6)2 has been determined by X-ray diffraction analysis. The complex exhibits a dppe ligand
bridging two CpRu(CH3CN)2 fragments.
Ó 2004 Elsevier B.V. All rights reserved.
Keywords: Ruthenium cyclopentadienyl complexes; Bidentate ligands; Crystal structure
1. Introduction
pseudotetrahedral complexes [CpꢀRuCl(L)2] [2b,3b,8]
and [CpꢀRu(L)2(CH3CN)]PF6 [7], respectively. Both the
chloride and the acetonitrile ligand in these complexes
may be exchanged with L0 species offering an easy route
to a vast variety of cationic compounds of formula
[CpꢀRu(L)2(L0)]PF6 [9,7]. Additional interest in such
species arises from their ability to form isolable, co-
ordinatively unsaturated 16-electron complexes [10]. In
contrast to the Cpꢀ derivatives, the chemistry of the
cyclopentadienyl ruthenium fragment is largely based on
the precursors [CpRu(CO)2Cl] and [CpRu(PPh3)2Cl]
[11]. However, the difficulties in performing selective
replacements of the ancillary ligands (PPh3 or CO) have
greatly limited the synthetic utility of such species [12].
The easily prepared [CpRu(CH3CN)3]PF6 [13], which
readily dissociates the acetonitrile molecules [14], is a
good synthon to prepare [CpRu(L)2(CH3CN)]þ cations
by reaction with a variety of monodentate phosphines
[15], and to synthesize catalytically active species [16]. In
an effort to further investigate the chemistry of
[CpRu(L)2] toward small molecules incorporating fifth
The well-known half sandwich ruthenium complexes
of the type [(C5R5)Ru(L)(L0)(L00)] (R ¼ H, CH3) have a
prominent role in the chemistry of the late transition
metals [1]. The [(C5R5)Ru(L)2] fragment, having kinet-
ically stable ruthenium–L bonds and high p-donor
ability, has been exploited to stabilize a variety of un-
stable p-acceptor ligands such as carbenes [2], vinylid-
enes [3a,3b,3c], allenylidenes [3d], sulphur oxides [4] or
white phosphorus [5], just to name a few. The chemistry
of the pentamethylcyclopentadienyl ruthenium fragment
is largely based on the tetramer [CpꢀRuCl]4 [6] and/or
on the Tris–acetonitrile [CpꢀRu(CH3CN)3]PF6 adduct
[7] which, upon addition of monodentate ligands, yield
q Supplementary data associated with this article can be found, in the
online version, at doi:10.1016/j.jorganchem.2004.02.035.
* Corresponding author. Tel.: +39(0)554573281; fax: +39(0)55457
3385.
E-mail address: piero.stoppioni@unifi.it (P. Stoppioni).
0022-328X/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2004.02.035

1758
M. Di Vaira et al. / Journal of Organometallic Chemistry 689 (2004) 1757–1762
group atoms, [5,17] we have reacted [CpRu(CH3
CN)3]PF6 with bidentate chelating ligands, L–L, [L–
L ¼ 1,2-bis(diphenylphosphino)ethane, dppe, and (1-
diphenylarsino-2-diphenylphosphino)ethane, dpadppe],
with the aim to obtain [CpRu(L–L)(CH3CN)]PF6
complexes containing a replaceable solvent molecule.
Apart from the originally targeted compounds, the re-
action resulted also in the formation of unexpected
diruthenium derivatives, whose synthesis and chemico-
physical properties are herein reported.
CH2Cl2, CH3CN and CH3NO2; their solutions are
stable under an inert atmosphere. The dimeric 4 and 7
complexes do not transform to 2 and 5 even if warmed
in CH2Cl2 for 24 h. A similar inertness has been
observed for the related neutral [{CpꢀRuCl}2(l-g1:1
-
dmpm)2] species [dmpm ¼ bis(dimethylphospino)meth-
ane] [8]. Similarly, the mononuclear species 2 and 5 do
not transform, upon treatment with one equivalent of
L–L, to 4 and 7. Complexes 2–7 have been characterized
by elemental analysis and NMR (1H and 31P) spectro-
scopy. Complexes 2 and 5 exhibit in their 31P spectrum a
low field singlet which is typical for a five-membered
1
2. Results and discussion
chelate ring [18]. The H spectra present the uninfor-
mative resonances of the ligand protons (see Section 3),
the cyclopentadiene singlet at ca. 4.9 ppm and the sig-
nals of the coordinated CH3CN molecule which appear
as a triplet (J ¼ 1:2 Hz) in compound 2, in accordance
with their coupling to the two phosphorus donors of
dppe and as a doublet in compound 5, due to the
presence of only one magnetically active phosphorus in
the ‘‘mixed’’ dpadppe ligand. Compounds 3, 4, 6 and 7
exhibit in their 31P NMR spectra resonances whose
shifts are typical for g1 bidentate ligands [18]. The in-
tensities of the ligand, cyclopentadiene and CH3CN
proton signals agree with the proposed formulae. The
spectra of compounds 6 and 7, containing the ‘‘mixed’’
dpadppe ligand, show some interesting features: that of
6 exhibits two separate resonances for the cyclopent-
adiene and for the coordinated CH3CN protons, due to
the inequivalence of the two CpRu(CH3CN)2 moieties
whose coordination is completed by either the P or the
As donor of the dpadppe ligand. Compound 7 exhibits
two singlets of slightly different intensities in the 31P
spectrum and two sets of proton resonances for both the
Three different products, as sketched in Scheme 1,
have been obtained upon treatment of [CpRu-
(CH3CN)3]PF6 (1) in CH2Cl2 with one equivalent of the
ligands dppe or dpadppe, which present either two
phophorus or one arsenic and a phosphorus atom as
donors, respectively. The reaction produces a yellow
crystalline precipitate of formula [{CpRu(CH3CN)2}2-
(L–L)](PF6)2 [L–L ¼ dppe (3), dpadppe (6)] and a yellow
solution yielding a solid of the same colour upon re-
moving the solvent. The extraction of the crude solid
with cold THF leaves undissolved a yellow compound
of formula [{CpRu(CH3CN)}2(L–L)2](PF6)2 [L–L ¼
dppe (4), dpadppe (7)], while the complexes [CpRu-
(CH3CN)(L–L)]PF6 [L–L ¼ dppe (2), dpadppe (5)] are
obtained from the THF extracts. The relative yields of
the three compounds do not change significantly on
changing the ligand (see Section 3). All of the com-
pounds may be handled in the air in the solid state; 2
and 5 are soluble in common organic solvents; 3 and 6
dissolve in CH3CN and CH3NO2; 4 and 7 are soluble in
L-L
dppe dpadppe
+
2
5
Ru
L
NCCH3
L
2+
NCCH3
NCCH3
Ru
Ru
+
L
3
6
CH3CN
L
+
Ru
L-L
NCCH3
CH3CN
NCCH3
NCCH3
1
2+
Ru
L-L = dppe, dpadppe
L
L
NCCH3
4
7
CH3CN
L
L
Ru
Scheme 1.

M. Di Vaira et al. / Journal of Organometallic Chemistry 689 (2004) 1757–1762
1759
bridging g1:1 bidentate ligands, represent a rare example
of ten-membered dimetalla macrocyclic complexes [20].
Crystals of 3 suitable for an X-ray diffraction anal-
ysis were obtained directly from the reaction of 1
and dppe in CH2Cl2. The structure of 3 consists of
[{CpRu(CH3CN)2}2(l-g1:1-dppe)]2þ dimetal cations
and PFꢁ6 anions in a 1:2 ratio. Each metal atom in the
centrosymmetric cation is coordinated by the cyclo-
pentadienyl ligand, by two acetonitrile nitrogens and by
a dppe phosphorus atom. A view of the cation is shown
in Fig. 1. Values of selected bond distances and angles
are given in Table 2. The RuCðCpÞ distances are in the
2+
Ru
P
As
As
NCCH3
CH3CN
P
Ru
(a)
2+
Ru
As
As
P
NCCH3
CH3CN
P
Ru
ꢁ
ꢁ
range 2.153–2.217 A and their 2.18(3) A average value
ꢁ
(b)
agrees with those, of 2.177(5) and 2.185 A, respectively,
found for the [CpRu(PMe3)(CH3CN)2]þ and [CpRu
(PCy3)(CH3CN)2]þ monomeric complex cations [15].
On the other hand, the present RuCðCpÞ distances are
appreciably longer than those found for the less crow-
Scheme 2.
cyclopentadiene and the CH3CN molecules (see Section
3): one set consists of a singlet for the cyclopentadiene
and a doublet for the coordinated acetonitrile, whereas
the other one consists of two singlets for the cyclo-
pentadiene and two resonances (a triplet and a singlet)
for the CH3CN. Such data are consistent with the
presence of two coordination isomers, Scheme 2, dif-
fering in the relative arrangement of the two dpadppe
donors; isomer b forms in a higher yield (ca. 55%)
compared with a; the metal atoms of isomer a are chiral.
Notably, the two complexes 4 and 7, containing two
ded [CpRu(CH3CN)3]þ synthon (2.135 A, average va-
ꢁ
ꢁ
lue) [14]. The RuN distances in 3, with 2.072(10) A mean
ꢁ
value, are slightly longer than those [2.055(5) A, mean]
found for the two Kirchner’s complexes formed with
ꢁ
two CH3CN ligands [15]. The present 2.318 A RuP
distance is intermediate between those, of 2.294(1) and
ꢁ
2.359 A, respectively, found for the [CpRu(PMe3)
(CH3CN)2]þ and [CpRu(PCy3)(CH3CN)2]þ cations [15].
The strong tendency of bidentate diphosphine ligands
such as dmpm, dppm and dcpm [dppm ¼ bis(diph-
Fig. 1. A view of the [{CpRu(CH3CN)2}2(dppe)]2þ centrosymmetric cation. Displacement ellipsoids are traced at the 20% probability level and H
atoms are shown as small circles with arbitrary radii. Only labels of symmetry-independent atoms are shown and those of phenyl carbon atoms are
omitted for clarity.

1760
M. Di Vaira et al. / Journal of Organometallic Chemistry 689 (2004) 1757–1762
enylphosphino)methane, dcpm ¼ bis(dicyclohexylphos-
phino)methane] to adopt an g1 or l-g1:1 (bridging)
coordination mode in the presence of ruthenium cyclo-
pentadienyl chloride fragments has been previously no-
ticed [8,9,19] and has been ascribed to the small bite of
the methylene backbone connecting the two donors. In
order to obtain an insight on the factors controlling the
formation of the mononuclear (2 and 5) and of the di-
metallic complexes having either one (3 and 6) or two (4
and 7) bridging ligands, the reaction between 1 and dppe
in 1:1 ratio has been investigated in CD3CN and
CD3NO2 solutions, all of the complexes being soluble in
such solvents, by collecting 31P NMR spectra at time
intervals. Upon mixing the reagents in CD3CN, 2 and 3
are detected in ca. 1:1 ratio, in addition to the free dppe
ligand. Afterwards, an increase in the amount of the
monoadduct 2 and a decrease in that of the free ligand
are observed. After two days the presence of 4, which
forms from 3 and the free ligand, is detectable; the
amount of 4 slowly increases for two days, after which
no more transformation is observed and the relative
molar ratios of the three compounds are: 60% for 2, 19%
for 3 and 21% for 4. Compounds 2, 3 and 4, in addition
to the uncoordinated dppe, are detected as soon as the
reagents are mixed in CD3NO2: 2 forms in a small
amount (8%), which does not change with time; 4 is the
dominant complex (yield 65%) and 3 occurs in a 25%
amount. In the following hours complex 3 and the free
ligand slowly yield 4. Constant ratios (8% for 2, 7% for 3
and 85% for 4) in the amounts of the three complexes
are reached within 15 h.
tris–acetonitrile adduct. The first route is accessible in
CH3CN, the second one in CH3NO2.
3. Experimental
3.1. General
All reactions and manipulations were performed under
an atmosphere of dry oxygen-free argon. The solvents
were purified according to standard procedures [21]. The
1H and 31P–{1H} NMR spectra were measured on a
Varian Gemini g300bb spectrometer, equipped with a
variable-temperature unit, operating at 300 MHz (1H)
and 121.46 MHz (31P). Chemical shifts are relative to
tetramethylsilane (1H) and to H3PO4 85% (31P) as exter-
nal standards at 0.00 ppm; coupling constants are given in
Hertz. Micoranalyses were done by the Microanalytical
Laboratory of the Department of Chemistry of the Uni-
versity of Firenze. [CpRu(CH3CN)3]PF6 (1) was prepared
according to the literature method [15]. The ligands 1,2-
bis(diphenylphosphino)ethane (Aldrich), dppe, and (1-
diphenylarsino-2-diphenylphosphino)ethane, (Pressure
Chemical Company), dpadppe, were used as purchased.
3.2. Synthesis of the complexes
3.2.1. [CpRu(dppe)(CH3CN)]PF6 (2)
A solution of dppe (120 mg, 0.30 mmol) in CH2Cl2 (5
cm3) was added at room temperature to [CpRu
(CH3CN)3]PF6 (1) (130 mg, 0.30 mmol) dissolved in
CH2Cl2 (8 cm3). The solution turned yellow immedi-
ately and a yellow crystalline solid formed after a few
minutes. The mixture was left at room temperature
overnight and filtered. The solvent of the filtrate was
removed under vacuum leaving a yellowish residue,
which was washed with diethyl ether (2 ꢂ 15 cm3) and
extracted with cold THF (2 ꢂ 10 cm3). Yellow micro-
crystals of 2 were obtained by concentrating the THF
extracts and by adding diethyl ether. The solid was
washed with petroleum ether (b.p. 40–60 °C) and dried
under vacuum. Yield: 95 mg (56%). Anal. Calc. (found)
for C33H32F6NP3Ru: C, 52.81 (52.90); H, 4.30 (4.40); N,
The above results show that at least one route to the
dimetal diligand complexes goes through the addition of
dppe to the dimetal monoligand compounds. Such ad-
dition occurs easily in CD3NO2 and slowly in CD3CN,
where the dissociation of the coordinated solvent is
disfavoured. Confirmatory evidence for the proposed
formation of 4 from 3 is provided by a separate exper-
iment in which pure 3 dissolved in CD3NO2 yields al-
most quantitatively
4
by treatment with the
stoichiometric amount of dppe (7 is recovered from 6,
by analogous treatment with dpadppe). It is admittedly
difficult to rationalize the drastic change of the distri-
bution of the different complexes on changing the sol-
vent. Anyhow, as observed by Girolami and coworkers
for the reaction of [CpꢀRuCl]4 with dppm, CH3CN fa-
vours the formation of the monometal complex [8]. On
the other hand, CH3NO2, favours the formation of di-
metallic compounds by easing the dissociation of the
coordinated solvent. From a mechanistic viewpoint, it is
likely that one acetonitrile molecule in 1 is easily re-
placed by a donor atom of the bidentate ligand to form
a bis acetonitrile g1-ligand metal intermediate. This may
yield 2 (or 5) by intramolecular replacement of a second
acetonitrile ligand, or afford 3 (or 6) via a dimolecular
process, by substitution of one acetonitrile in a second
1
1.87 (1.79). H NMR [d, (CD3)2CO, 20 °C]: 7.90–7.40
(20H, m, Ph), 4.89 (5H, s, Cp), 2.80 (2H, br, CH2), 2.74
(2H, br, CH2), 1.65 (3H, t, 5JHP ¼ 1:2, CH3). 31P NMR:
1
80.7 (2P, s, dppe), )142.7 (1P, sept, JPF ¼ 709:5, PF6).
3.2.2. [{CpRu(CH3CN)2}2(l-dppe)](PF6)2 (3)
The complex was isolated as yellow crystals after
washing with diethyl ether (2 ꢂ 15 cm3) and drying the
solid which separated out from the reaction of 1 with
dppe in CH2Cl2 (see above). Yield: 73 mg (22%). Anal.
Calc. (found) for C44H46F12N4P4Ru2: C, 44.60 (44.60);
H, 3.91 (3.88); N, 4.73 (4.69). 1H NMR (d, CD3NO2, 20
°C): 7.60–7.41 (20H, m, Ph), 4.49 (10H, s, Cp), 2.59 (4H,

M. Di Vaira et al. / Journal of Organometallic Chemistry 689 (2004) 1757–1762
1761
br, CH2), 2.16 (12H, s, CH3). 31P NMR: 45.5 (1P, s,
dppe), )142.9 (1P, sept, JPF ¼ 707:5, PF6).
All operations were performed at room temperature
using a Bruker CCD goniometer mounted on a rotating-
1
ꢁ
anode generator, with Cu Ka radiation (k ¼ 1:54184 A).
3.2.3. [{CpRu(CH3CN)}2(l-dppe)2](PF6)2 (4)
This product was obtained as yellow crystals col-
lecting and drying the solid remaining after extraction
with THF in the procedure described above. Yield: 11
mg (12%). Anal. Calc. (found) for C66H64F12N2P6Ru2:
C, 52.81 (52.73); H, 4.30 (4.35); N, 1.87 (1.83).1H NMR
(d, CD2Cl2, 20 °C) 7.61–7.04 (40H, m, Ph), 4.28 (10H, s,
Cp), 2.45 (4H, m, CH2), 2.26 (4H, m, CH2), 1.96 (6H, s,
CH3). 31P NMR: 38.7 (2P, s, dppe), )142.9 (1P, sept,
1JPF ¼ 709:5, PF6).
Cell constants were obtained by least-squares refinement
of the setting angles for 813 reflections in the range
7:6 < 2h < 100:9°. A correction for absorption was ap-
plied with SADABS [22]. The structure was determined
by direct methods [23] and refined on F 2 [24], aniso-
tropically for the nonhydrogen atoms. Hydrogens were
in calculated positions, riding, with isotropic tempera-
ture factors linked to the Ueq of the respective carrier
atoms. Features in the final difference synthesis were low
and devoid of chemical meaning. Computer programs
used included PARST [25] for geometry calculations, and
ORTEP [26,27] for graphics (Table 1).
The dpadppe compounds [CpRu(dpadppe)( CH3CN)
]PF6 (5), [{CpRu(CH3CN)2}2(l-dpadppe)] (PF6)2 (6)
and [{CpRu(CH3CN)}2(l-dpadppe)2](PF6)2 (7) were
obtained by adding the stoichiometric amount of the
ligand in CH2Cl2 (5 cm3) to [CpRu(CH3CN)3]PF6 (1)
(0.3 mmol) in CH2Cl2 (7 cm3) and working up the
mixture as described above for the preparation of the
dppe complexes 2, 3 and 4.
Table 1
Crystal data and structure refinement parameters for 3
Formula
C44H46F12N4P4Ru
1184.87
Monoclinic
Formula weight
Crystal system
Space group
3.2.4. [CpRu(dpadppe)(CH3CN)]PF6 (5)
Yield: 122 mg (53%). Anal. Calc. (found) for
C33H32AsF6NP2Ru: C, 49.89 (49.75); H, 4.06 (4.16); N,
P21=c
8.909(1)
ꢁ
a (A)
ꢁ
b (A)
14.859(1)
18.924(1)
ꢁ
c (A)
1
1.76 (1.69). H NMR [d, (CD3)2CO, 20 °C]: 7.95–7.41
(20H, m, Ph), 4.92 (5H, s, Cp), 2.91 (2H, m, CH2), 2.53
b (°)
V (A )
99.94(1)
2467.5(3)
3
ꢁ
(2H, m, CH2), 1.71 (3H, d, 5JHP ¼ 1:3, CH3). 31P NMR:
Z
4
1.595
6.90
1
83.4 (1P, s, PPh2), )142.7 (1P, sept, JPF ¼ 708:0, PF6).
Dcalc (g cmꢁ3
)
l (mmꢁ1
)
Transmission factors range
Crystal size (mm)
F ð000Þ
0.549–1.000
0.08 ꢂ 0.08 ꢂ 0.05
1188
3.2.5. [{CpRu(CH3CN)2}2(l-dpadppe)](PF6)2 (6)
Yield: 54 mg (25%). Anal. Calc. (found) for
C44H46AsF12N4P3Ru2: C, 43.01 (42.85); H, 3.77 (3.75);
N, 4.56 (4.47). 1H NMR (d, CD3NO2, 20 °C): 7.58–7.41
(20H, m, Ph), 4.52 (5H, s, Cp), 4.49 (5H, s, Cp), 2.66
(2H, m, CH2), 2.56 (2H, m, CH2), 2.15 (6H, d,
5JHP ¼ 1:4, CH3), 2.14 (6H, s, CH3). 31P NMR: 45.9
h range (°)
3.80–50.80
ꢁ8 6 h 6 8, ꢁ14 6 k 6 14,
ꢁ18 6 l 6 18
8065
Index ranges
Reflections collected
Independent reflections
Independent observed reflections
Restraints/parameters
2510 [Rint ¼ 0:089]
1900 [I > 2rðIÞ]
0/298
1
(1P, s, PPh2), )142.9 (2P, sept, JPF ¼ 707:5, PF6).
Final R indices ½I > 2rðIÞꢃ
R indices (all data)
R1 ¼ 0:072, wR2 ¼ 0:165
R1 ¼ 0:101, wR2 ¼ 0:177
1.120
3.2.6. [{CpRu(CH3CN)}2(l-dpadppe)2](PF6)2 (7)
Yield: 28 mg (12%). Anal. Calc. (found) for
C66As2H64F12N2P4Ru2: C, 49.89 (49.66); H, 4.06 (3.97);
Goodness of fit on F 2 (all data)ꢁ3
ꢁ
Residual electron densities (e A
)
0.80 to )0.63
1
N, 1.76 (1.72). H NMR (d, CD2Cl2, 20 °C) major iso-
mer: 7.71–7.02 (40H, m, Ph), 4.37 (5H, s, Cp), 4.24 (5H,
5
s, Cp), 2.44–2.23 (8H, m, CH2), 2.03 (3H, t, JHP ¼ 1:2,
CH3), 1.80 (3H, s, CH3). 31P NMR: 40.9 (1P, s, PPh2),
Table 2
ꢁ
Selected bond lengths (A) and bond angles (°) for 3
1
)142.9 (1P, sept, JPF ¼ 709:5, PF6). Minor isomer:
Bond lengths
7.71–7.02 (40H, m, Ph), 4.32 (10H, s, Cp), 2.44–2.23
(8H, m, CH2), 1.96 (6H, d, 5JHP ¼ 1:4, CH3). 31P NMR:
Ru–P
2.318(3)
Ru–C(15)
Ru–C(16)
Ru–C(17)
Ru–C(18)
2.217(14)
2.166(14)
2.161(14)
2.153(14)
Ru–N(1)
Ru–N(2)
Ru–C(14)
2.075(11)
2.070(10)
2.198(15)
1
41.0 (1P, s, PPh2), )142.9 (1P, sept, JPF ¼ 709:5, PF6).
3.3. X-ray crystallography of [{CpRu(CH3CN)2}2(l-
dppe)](PF6)2 (3)
Bond angles
P–Ru–N(1)
P–Ru–N(2)
93.2(3)
93.0(3)
N(1)–Ru–N(2)
a
Cn–Ru–Cm
87.3(4)
36.7(8)
a Mean value of angles to the metal formed by contiguous Cp
carbons.
Crystals of the compound were all of very small size,
which posed limitations on the intensities of reflections.

1762
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