The synthesis and characterisation of bis(phosphane)-linked (η6-p-cymene)-ruthenium(II)-borane compounds

Article abstract of DOI:10.1002/ejic.200500706

The reaction of [(η⁶-p-cymene)RuCl₂]₂ with some bis(phosphane) ligands (dppm, dppe, dppv, dppa, dpp14b, dppf) has been investigated. In general mixtures of products were obtained, although the pendant phosphane complexes [

Full text of DOI:10.1002/ejic.200500706

FULL PAPER
DOI: 10.1002/ejic.200500706
The Synthesis and Characterisation of Bis(phosphane)-Linked (η6-p-Cymene)-
ruthenium(II)–Borane Compounds
Adrian B. Chaplin,[a] Rosario Scopelliti,[a] and Paul J. Dyson*[a]
Keywords: Ruthenium / P ligands / Bridging ligands / Coordination modes / Boranes
The reaction of [(η6-p-cymene)RuCl2]2 with some bis(phos-
phane) ligands (dppm, dppe, dppv, dppa, dpp14b, dppf) has
been investigated. In general mixtures of products were ob-
tained, although the pendant phosphane complexes [(η6-p-
cymene)RuCl2(η1-dppv)] and [(η6-p-cymene)RuCl2(η1-dppa)]
were isolated and characterized in the solid state by X-ray
diffraction. The later complex was obtained in lower yield
and undergoes an equilibration reaction resulting in the for-
mation of a dimeric species, where the dppa bridges two ru-
thenium centres, and uncoordinated phosphane; the bridg-
ing species was also structurally characterised in the solid
state. In contrast, the reaction of [(η6-p-cymene)RuCl2(PPh3)]
tion of [(η6-p-cymene)RuCl(PPh3)(η1-dppa)]PF6, which is
stable in solution. A series of linked ruthenium–borane com-
plexes, viz. [(η6-p-cymene)RuCl2(η1-phosphane-BH3)] (phos-
phane = dppm, dppe, dppv, dppa, dpp14b, dppf) and [(η6-p-
cymene)RuCl(PPh3)(η1-dppa-BH3)]PF6 have been prepared
from isolated pendant phosphane complexes, those gener-
ated in situ, or from a preformed phosphane–borane adduct.
The solid-state structures of [(η6-p-cymene)RuCl2(η1-dppm-
BH3)], [(η6-p-cymene)RuCl2(η1-dppe-BH3)] and [(η6-p-cy-
mene)RuCl2(η1-dppv-BH3)] have been determined by X-ray
diffraction analysis.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
with dppa in the presence of [NH4]PF6 results in the forma- Germany, 2005)
we describe the preparation of model-linked (η6-p-cymene)-
ruthenium(ii) systems using bis(phosphane) ligands.
Introduction
The use of chelating phosphane ligands is prevalent in
For these linked systems the borane moiety, BH3, was
the coordination chemistry of the transition metals,[1] with selected as a model-linked species as phosphane–borane ad-
complexes incorporating chelating phosphane ligands find- ducts are formed rapidly and tend to be thermally stable.[10]
ing many applications in catalysis, where the versatility of Furthermore, coordination of a phosphane to BH3 is a
this ligand class has allowed the rational design of highly common method for protecting valuable (usually chiral)
active and selective compounds.[2] Bis(phosphane) ligands phosphanes from oxidation, either during storage or during
can also be found to bridge metal centers and coordinate synthetic transformations.[10] Phosphane–borane adducts
selectively through one phosphorus centre, leading the have also been used as bidentate ligands, coordinating
other end free.[3–5] Such pendant coordination provides a through a P centre and agostic B–H interactions (a,[11] b,[12]
way to link a variety of fragments, including simple metal c–e[13] in Figure 1). In addition, as models for metallo-
complexes, metal cluster compounds, and main group frag- borane ruthenium clusters, Barton and co-workers have
ments.[3c–g,4,6]
previously prepared [(η6-p-cymene)RuCl2PPh2CH2C6H4-
Ruthenium(ii) complexes have well documented catalytic CH2PPh2BH3] (f) and [(η6-p-cymene)RuCl2PPh2(CH2)6-
utility in organic chemistry,[2d] among which half sandwich PPh2BH3] (g) from the reaction of either isolated or in-situ
(η6-arene)ruthenium(ii) complexes constitute an important generated (η6-p-cymene)ruthenium pendant phosphane
class. As part of our continuing investigation of these com- complexes with BH3·THF.[4]
plexes for catalytic hydrogenation reactions,[7] we have em-
barked on developing methodologies for the preparation of
compounds in which the catalytically active ruthenium frag-
ment is linked to other metal and non-metal moieties. These
include functionalisation of the coordinated arene with
imidazolium groups or crown ether moieties,[8] and forma-
tion of a heterometallic carbene complex.[9] In this paper
Results and Discussion
The direct reaction between [(η6-p-cymene)RuCl2]2 and
bis(phosphane) ligands in a 1:2 ratio generally results in the
formation of the desired pendant phosphane complexes,
viz. [(η6-p-cymene)RuCl2(η1-phosphane)], together with
other ruthenium-containing species. In the case of poten-
tially chelating phosphane ligands, formation of the η2-co-
ordinated complex, presumably following initial η1-coordi-
nation followed by intramolecular chloride substitution,
[a] Institut des Sciences et Ingénierie Chimiques, Ecole Polytech-
nique Fédérale de Lausanne (EPFL),
1015 Lausanne, Switzerland
E-mail: paul.dyson@epfl.ch
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FULL PAPER
Figure 1. Examples of metal-containing phosphane–borane adducts.
can be suppressed by avoiding polar solvents, such as meth- for 2 and the other compounds described herein are listed
anol and ethanol, which promote chloride loss. In such a in Table 1.
way the previously reported complex [(η6-p-cymene)-
RuCl2(η1-dppm)] (1) has been prepared in high yield (76%)
[7a] using benzene as a solvent.[5,7a] However, reaction of the
phosphane ligands investigated in this report, see Figure 2,
even in large excess, with [(η6-p-cymene)RuCl2]2 in dichlo-
romethane generally resulted in the formation of mixtures
composed of the η1-coordinated phosphane complex and a
linked ruthenium–ruthenium complex where the phosphane
ligand bridges the two metal centres. The cis-bis(1,2-di-
phenylphosphanyl)ethylene (dppv) ligand was, however, a
Figure 2. Bis(phosphane)s used in this study with their abbrevi-
ations.
notable exception to this generalisation, forming only the
desired pendant phosphane complex [(η6-p-cymene)-
RuCl2(η1-dppv)] (2) in 89% yield using a stoichiometric
phosphane to ruthenium ratio. The η1-coordination mode
To provide a possible explanation for the selective forma-
is clearly evidenced by the presence of two doublets at δ = tion of these pendant phosphane complexes the solid-state
15.1 and –30.6 ppm (3JPP = 9.1 Hz) in the 31P NMR spec- structures of 2 and the oxide derivative of 1, [(η6-p-cymene)-
trum, with the high-frequency resonance corresponding to RuCl2(η1-dppmO)] (3), obtained by slow oxidation of 1 in
the coordinated P centre. Selected NMR spectroscopic data solution over a period of months,[16] were determined by X-
Table 1. Selected 31P and 11B NMR spectroscopic data.[a]
Noncoordinated Pendant phosphane complex
Bridged
Ru–P
Phosphane–borane complex
Ru–P
pend-P
JPP
Ru–P
PBH3
JPP
PBH3
dppm
dppe
dppv
dppa
PPh3dppa –32.0
dppf
–22.4
–12.5
–23.1
–32.0
26.1[5c]
25.5
15.1
0.4[b]
1.0
–27.6[5c]
–12.6
–30.6
–34.2[b]
–31.7
–17.6
–5.2
31.8
34.8
9.1
21.1[14]
22.5[7a]
12.0
22.7
23.6
18.4[b]
3.2[b]
5.7
18.5
24.9
11.9
18.2
9.2[b]
5.8[b]
7.8
15.8
20.5
33.5
–38.4
42.8
–40.6
12.9[b]
–37.3[b]
–37.3[b]
–37.7
3.6[b]
4.0
10.1[15]
29.7,–2.8[c]
18.3[14]
24.6
–17.2
–5.6
19.0
24.2
–38.5
–38.1
dpp14b
[a] CDCl3, 298 K. Chemical shifts in ppm and coupling constants, J, in Hz. [b] 248 K. [c] 2JPP = 56.9 Hz.
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ray diffraction analysis (see Figure 3 and Figure 4). The so- particular relevance to the reactivity of the pendant phos-
lid-state structure of 3 is much the same as that of 1,[5b,5c] phane is the close proximity of the P centres in both 2 and
and the related pendant oxide complex [(η6-p-cymene)- 3 (and 1). In the case of 2, with a P···P distance of
RuCl2{η1-PPh2PCH(CH3)P(O)Ph2}] (4).[17] Each adopt the 3.481(3) Å, the close approach originates from the cis con-
expected “piano-stool” geometries, with the phosphane formation of the alkene backbone, whereas in 3 the close
chelate angle directed away from the chloride ligands. The approach [3.173(6) Å – averaged over the asymmetric cell,
Ru–P bond length in 3 is similar to that in 1 [2.355(7) vs. cf. 1, 3.138(2) Å][5b] is a consequence of the small chelate
2.368(7)[5b] Å], and the P–O bond in 3 is comparable with angle [120.6(7)°]. These constraints provide a satisfactory
that in 4 [1.49(1) vs. 1.484(3) Å]. The structure of 2 bears explanation for the selective formation of the pendant phos-
close resemblance to 1 and 3 in many respects including the phane complexes for dppm and dppv, as the steric bulk
conformation of phosphane with respect to the ruthenium from the coordinated phosphane moieties, notably from the
arene moiety and the Ru–P bond length [2.362(2) Å]. Of phenyl groups, can act to hinder further coordination.
Figure 3. Ball-and-stick depiction of 2 in the solid state. Key bond lengths [Å] and angles [°]: Ru1–Cl1, 2.438(2); Ru1–Cl2, 2.418(1); Ru1–
P1, 2.362(2): Cl1–Ru1–Cl2, 89.26(5); Cl1–Ru1–P1, 86.82(6); Cl2–Ru1–P1, 82.58(5); Ru1–Cavg, 2.21(3); Ru1–centroid, 1.7002(4); P1–C11,
1.833(5); P2–C12, 1.845(5); C11–C12, 1.336(7); P1–C11–C12, 126.9(4); P2–C12–C11, 124.4(4).
Figure 4. Ball-and-stick depiction of 3 in the solid state [selected molecule from the asymmetric cell]. Key bond lengths [Å] and angles
[°] [averaged over asymmetric cell]: Ru–Cl, 2.432(7); Ru–ClЈ, 2.420(3); Ru–P, 2.355(7): Cl–Ru–ClЈ, 88.7(9); Cl–Ru–P, 87.2(9); ClЈ–Ru–P,
83.4(8); Ru–Cavg, 2.21(2); Ru–centroid, 1.700(5); P–C, 1.84(2); PЈ–C, 1.82(1); P–C–PЈ, 120.6(7); PЈ–O, 1.49(1).
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The competing formation of the bridged diruthenium mene)}]+, moderately stable in solution,[18] can be dismissed
species, by coordination of the pendant P centre to another because it was not detected by NMR spectroscopy during
ruthenium unit, encumbers the isolation of the desired pen- the equilibration process.
dant phosphane complexes. For example, the pendant phos-
Using toluene as the solvent instead of dichloromethane
phane complex, [(η6-p-cymene)RuCl2(η1-dppa)] (5) was for the reaction between [(η6-p-cymene)RuCl2]2 and dppa
separated from the corresponding bridged species [(η6-p-cy- (1.1 equiv. per Ru, room temperature), 6 selectively precipi-
mene)RuCl2(μ-dppa)RuCl2(η6-p-cymene)] (6), in ca. 17% tates on formation, driving the equilibrium to the right
yield, following successive recystallisations from dichloro- hand side, resulting in a 5/6 product distribution of ca. 2
methane/pentane at –20 °C. Compound 5 is, however, un- compared to the equilibrium ratio of 0.63.[19] The reaction
stable at room temperature and undergoes an equilibration was also carried out in dichloromethane at –78 °C with an
reaction, liberating free phosphane and generating the excess of phosphane (2.3 equiv. per Ru). The resultant ratio
bridged species 6, as depicted in Scheme 1. After ca. 1 day of 5/6 was ca. 0.2, as determined by 31P NMR spectroscopy,
in CDCl3 an equilibrium composition is reached, corre- much lower than that of the equilibrium composition. Be-
sponding to an equilibrium constant of K = 0.42 (Figure 5). low –50 °C the rate of formation of 6 is slow enough to
Likewise, this equilibration can also be effected starting allow NMR characterisation of 5. The 31P NMR spectrum
from 6 and dppa (Ϸ 1:1) on a similar timescale (ca. 1 day (as for complex 2) displays the characteristic pair of doub-
at room temperature in CDCl3). Both these reactions follow lets, with the coordinated phosphane resonance at δ = 0.4
first-order reaction kinetics, consistent with a mechanism and the pendant P centre at δ = –34.2, although the coup-
3
involving dissociation of dppa and formation of the coordi- ling constant, JPP, is reduced in comparison to 2 [9.1 vs.
nately unsaturated arene ruthenium species “[(η6-p-cymene)- 3.6 Hz]. The solid-state structures of 5 and 6 have been de-
RuCl2]”, as depicted in Scheme 1. An alternative proposal termined by X-ray diffraction analysis, and are depicted in
in which chloride dissociation leads to the intermediate spe- Figure 6 and Figure 7, respectively. Each have “piano-
cies [(η6-p-cymene)RuCl2(η1-dppa){(μ-dppa)RuCl2(η6-p-cy- stool” geometries about the Ru centres, although as sug-
Scheme 1. Proposed mechanism for the equilibration of [(η6-p-cymene)RuCl2(η1-dppa)] (5) with [(η6-p-cymene)RuCl2(μ-dppa)RuCl2(η6-
p-cymene)] (6).
Figure 5. Equilibrium between complexes 5 and 6 at room temperature in CDCl3. Relative concentrations of 5 (circles) and 6 (squares)
1
were determined by integration of H NMR spectroscopic data. Note, the concentration of dppa is not shown as it is identical to that
of 6.
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gested by the difference in the coordinated phosphane reso- nate from the steric constraints present in 6 owing to the
nances [5, δ = 0.4; 6,[15] δ = 10.1] there are slight differences rigid backbone of the dppa ligand, which deviates from lin-
in the coordination sphere geometries. In particular the Ru– earity slightly more in 6.
P bond in 5, is elongated in comparison to 6 [2.336(1) vs.
To further investigate the coordination chemistry of dppa
2.319(1) Å] together with increased Cl–Ru–P angles it was reacted with the monosubstituted triphenylphos-
[87.18(8) vs. 85.1(7)°] and a reduced Cl–Ru–Cl angle phane derivative [(η6-p-cymene)RuCl2(PPh3)] together with
[86.08(4) vs. 88.10(4)°]. These differences are likely to origi- one equivalent of [NH4]PF6 in methanol, resulting in the
selective formation of the cationic pendant phosphane com-
plex [(η6-p-cymene)RuCl(PPh3)(η1-dppa)]PF6 (7). The pro-
posed structure was unambiguously identified by NMR
spectroscopy, ES-MS and elemental analysis. The 31P NMR
spectrum shows three distinct phosphane resonances; a
2
high-frequency doublet at δ = 24.2 ppm (Ru–PPh3, JPP
=
55.1 Hz),
a doublet of doublets at δ = 1.0 (Ru–
2
3
PPh2CCPPh2, JPP = 55.1, JPP = 3.2 Hz), and low fre-
quency doublet at δ = –31.7 ppm corresponding to the pen-
dant P centre (3JPP = 4.9 Hz), in accordance with the pro-
posed structure. In contrast to 5, the cationic complex 7 is
stable in solution over long periods of time, as evidenced
by no discernible changes in its 31P NMR spectrum after
ca. 3.5 days in CDCl3 solution. In 7 the signal of the quater-
nary carbon of the isopropyl group at the p-cymene ring
(C4 in Figure 8) is located at δ = 129.7 ppm by 1H,13C long-
range correlation NMR spectroscopy, ca. 20 ppm to higher
frequency than in 5 and 6 (and also to the other ruthenium
complexes). This is indicative of weaker coordination to the
metal centre, presumably from the increased steric bulk in
the ruthenium coordination sphere. The ES-MS spectrum
recorded in MeOH exhibits a strong molecular ion peak
at m/z +927 with the expected isotope pattern. Structural
information was obtained by selective fragmentation[20] of
the parent peak resulting primary in loss of the PPh3 ligand.
Figure 6. Ball-and-stick depiction of 5 in the solid state. Key bond
lengths [Å] and angles [°]: Ru1–Cl1, 2.418(1); Ru1–Cl2, 2.402(1);
Ru1–P1, 2.336(1): Cl1–Ru1–Cl2, 86.08(4); Cl1–Ru1–P1, 87.12(5);
Cl2–Ru1–P1, 87.24(5); Ru1–Cavg, 2.21(2); Ru1–centroid, 1.7006(5);
P1–C11, 1.782(5); P2–C12, 1.765(6); C11–C12, 1.202(7); P1–C11–
C12, 175.1(5); P2–C12–C11, 174.0(5).
Figure 7. Ball-and-stick depiction of 6 in the solid state. Symmetry equivalent atoms, labeled with an A, are obtained by the symmetry
operation –x, –y, 2 – z. Key bond lengths [Å] and angles [°]: Ru1–Cl1, 2.403(1); Ru1–Cl2, 2.204(1); Ru1–P1, 2.319(1): Cl1–Ru1–Cl2,
88.10(4); Cl1–Ru1–P1, 84.56(4); Cl2–Ru1–P1, 85.56(4); Ru1–Cavg, 2.22(3); Ru1–centroid, 1.7045(3); P1–C11, 1.762(4); C11–C11#,
1.207(8); P1–C11–C11#, 172.4(5).
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achieved by extraction of the solid residue with toluene and
recyrstallisation from dichloromethane/pentane, although
chromatography is necessary for complete separation.
Scheme 2. Preparation of 1B, 2B, 5B and 7B.
A high-yielding method for the preparation of the ruthe-
nium–borane species linked with the 1,4-bis(diphenylphos-
phanyl)benzene ligand (dpp14b) has been devised. The
route, depicted in Scheme 4, involves the reaction of a pre-
formed phosphane–borane, prepared in good yield (61%, 2
steps) from 1,4-bromo(diphenylphosphane)benzene, di-
rectly with [(η6-p-cymene)RuCl2]2 (82% yield).
Large shifts of ca. δ = 35 ppm (see Table 1) and charac-
teristic line broadening of the pendant P-centre resonances
are observed in the 31P NMR spectra for the ruthenium–
borane complexes, although the frequencies of the coordi-
nated P-centre resonances remain similar. Distinctive reso-
1
Figure 8. Section of the H,13C long-range correlation NMR spec-
3
trum of 7. Cross peaks originate from JCH couplings (CDCl3,
room temperature).
Synthesis and Characterisation of Ruthenium–Borane
Adducts
The isolated pendant phosphane complexes, 1, 2, 5 and nances at ca. δ = –38 ppm in the 11B NMR spectra (see
7, react readily with BH3·THF to give the corresponding Table 1) are in agreement with related, previously reported,
ruthenium–borane adducts, 1B, 2B, 5B and 7B, in good phosphane–borane adducts.[4] 1H and 13C NMR spectro-
yield as depicted in Scheme 2. For complexes 5 and 7, it scopic data for complexes 1B, 2B, 5B, and 7B are compar-
was necessary to carry out the reaction at –78 °C to prevent able with those of the isolated pendant phosphane com-
hydroboration of the alkyne moiety. Similarly, complexes plexes. In particular, the signal of the isopropyl quaternary
8B (dppe) and 9B (dppf) can be prepared by reaction of carbon of the p-cymene ring in 7B is similarly located at
BH3·THF with the corresponding pendant phosphane com- high frequency (δ = 131 ppm) as observed for 7. The ES-
plexes formed, instead, in situ (Scheme 3). Partial separa- MS spectrum of 7B in MeOH exhibits a peak at m/z +927
tion from the corresponding bridging species, formed in resulting from loss of BH3. If dichloromethane is used in-
parallel to the pendant phosphane complexes, can be stead, the molecular ion peak at m/z +941 is observed to-
Scheme 3. Preparation of 8B and 9B.
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Scheme 4. Stepwise preparation of 10B. Reagents and conditions:
i. BH3·THF, 0 °C; ii. BuLi, –78 °C, followed by ClPPh2; iii. [(η6-p-
cymene)RuCl2]2, room temp.; overall yield: 50%.
gether with a weaker peak at m/z +927. MS/MS of the
parent peak correspondingly results in loss of BH3, further
selective fragmentation of this peak results resulting
primary in loss of the PPh3 ligand as for 7.
Spectroscopic data for complexes 8B, 9B and 10B corro-
borate the structure of the complexes well. Using NOESY
it was possible to unambiguously determine the conforma-
tion of the dppf ligand in solution in 9B, as depicted in
Figure 9. In this conformation, the ferrocenyl rings adopt
the expected antiperiplanar configuration, with both the
borane moiety and ruthenium centre directed away from
the ligand.
Figure 9. Section of the NOESY spectrum of 9B (CDCl3, room
temperature).
The solid-state structures of the complexes 1B, 2B and
8B have been determined by X-ray diffraction analysis and
are depicted in Figure 10, Figure 11 and Figure 12. Com-
plexes 1B and 2B retain similar conformations as their par-
ent pendant phosphane complexes 1[5b] (also 3, Figure 4)
and 2 (Figure 3), although in both cases Ru–P bond lengths
are slightly contracted in the borane adducts [2.351(2) vs.
2.368(7) Å for dppm; 2.3424(8) vs. 2.362(2) Å for dppv].
The structure of complex 8B exhibits similar bonding pa-
rameters around the ruthenium centre to those observed in
the related bridging species [(η6-p-cymene)Ru(S2C2-
{B10H10})(μ-dppe)Ru(S2C2{B10H10})(η6-p-cymene)].[21]
The P–B bond lengths range from 1.91–1.93 Å and are
comparable to other phosphane–BH3 adducts.[4,12,13]
In conclusion, a series of neutral bis(phosphane)-linked
ruthenium–borane complexes have been prepared using a
variety of phosphane ligands. While the use of isolated pen-
dant phosphane complexes is more desirable and higher
yielding, the formation of these complexes is usually ac-
companied by the formation of dimeric ruthenium–ruthe-
nium species. In the case of the reaction between bis(di-
phenylphosphanyl)acetylene (dppa) and [(η6-p-cymene)-
Figure 10. Ball-and-stick depiction of 1B in the solid state. The
minor disordered component of the p-cymene ring is composed of
atoms C11–C13. Key bond lengths [Å] and angles [°]: Ru1–Cl1,
2.417(2); Ru1–Cl2, 2.393(2); Ru1–P1, 2.351(2): Cl1–Ru1–Cl2,
85.65(8); Cl1–Ru1–P1, 86.47(9); Cl2–Ru1–P1, 87.33(8); Ru1–Cavg
2.19(3); Ru1–centroid, 1.7045(6); P1–C14, 1.831(8); P2–C14,
RuCl2]2, equilibration between these two species occurs in 1.841(8); P1–C14–P2, 123.4(4); P2–B1, 1.91(1).
,
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Figure 11. Ball-and-stick depiction of 2B in the solid state. Key bond lengths [Å] and angles [°]: Ru1–Cl1, 2.4107(8); Ru1–Cl2, 2.4307(8);
Ru1–P1, 2.3424(8): Cl1–Ru1–Cl2, 88.11(3); Cl1–Ru1–P1, 83.32(3); Cl2–Ru1–P1, 86.28(3); Ru1–Cavg, 2.22(4); Ru1–centroid, 1.7116(3);
P1–C11, 1.823(3); P2–C12, 1.813(3); C11–C12, 1.327(4); P1–C11–C12, 139.3(3); P2–C12–C11, 135.3(3); P2–B1, 1.932(4).
Figure 12. Ball-and-stick Depiction of 8B in the solid state. Key bond lengths [Å] and angles [°]: Ru1–Cl1, 2.436(2); Ru1–Cl2, 2.413(2);
Ru1–P1, 2.356(2): Cl1–Ru1–Cl2, 88.86(5); Cl1–Ru1–P1, 90.42(6); Cl2–Ru1–P1, 84.49(6); Ru–Cavg, 2.21(2); Ru1–centroid, 1.7005(5); P1–
C11, 1.858(5); P2–C12, 1.817(6); C11–C12, 1.538(8); P1–C11–C12, 113.0(4); P2–C12–C11, 112.8(4); P2–B1, 1.933(8).
solution. In contrast, the reaction between cis-bis(1,2-di- linked ruthenium–borane systems using these ligands are
phenylphosphanyl)ethylene (dppv) and [(η6-p-cymene)- prepared in lower yield and require chromatographic purifi-
RuCl2]2 results in the selective formation of the pendant cation. As an alternative methodology, a preformed phos-
phosphane complex akin to dppm. These observations were phane–borane ligand was prepared preventing contami-
rationalised by inspection of their solid-state structures nation from the corresponding bridging species.
(and related oxide and borane adducts), which show a close
proximity between the P centres. In contrast for dppe and
Experimental Section
dppf the solid-state structure and solution conformation de-
termined by NOESY, respectively, of the linked ruthenium–
borane complexes are suggestive (vide infra) of little steric
All organometallic manipulations were carried out under nitrogen
using standard Schlenk techniques. CH2Cl2, diethyl ether, hexane,
hindrance to further coordination. Correspondingly, the THF and toluene were dried using a solvent purification system,
Eur. J. Inorg. Chem. 2005, 4762–4774
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4769

A. B. Chaplin, R. Scopelliti, P. J. Dyson
FULL PAPER
2
manufactured by innovative technology inc., in which nitrogen-sat-
urated solvents are passed through a series of alumina columns or,
for the hydrocarbons, through one column of alumina then another
containing a copper catalyst under a positive pressure of nitrogen.
All other solvents were p. a. quality and saturated with nitrogen
prior to use. Chromatographic separations were carried out in air
using 1.0×20×20 mm silica gel 60 F254 plates (Merck). [(η6-p-cy-
mene)RuCl2]2,[22] [(η6-p-cymene)2Ru2(μ-Cl)3]PF6,[23] [(η6-p-cymene)-
RuCl2(PPh3)],[23] [(η6-p-cymene)RuCl2(η1-dppm)],[7a] dpp14b,[24]
and 1,4-bromo(diphenylphosphane)benzene,[24] were prepared as
described elsewhere. All other chemicals are commercial products
and were used as received. Spectra were recorded with a Bruker
Avance 400 spectrometer at room temperature, unless otherwise
stated. Chemical shifts are given in ppm and coupling constants
(J) in Hz. ES mass spectra were recorded with a Thermo Finnigan
LCQ DECA XPPlus and microanalyses performed at the EPFL.
Numerical analysis for the equilibration of 5 – (6 + dppa) was
carried out using Origin 7.5 (OriginLab).
0.1–0.7 [br., 3 H, BH3; {11B@δ = –37.3} δ = 0.42, d, JPH = 16.3].
1
13C{1H} NMR (CDCl3, –50 °C): δ = 145.6 (d, JPC = 39.0,
2
PPh2CH), 133.8 [d, JPC = 10.0, RuP(o-C6H5)2], 133.3–133.9 (ob-
2
scured, PPh2CH), 132.1 [d, JPC = 9.5, P(o-C6H5)2BH3], 131.4 [br.,
1
RuP(p-C6H5)2], 131.2 [br., P(p-C6H5)2BH3], 130.7 [d, JPC = 47.5,
1
3
P(i-C6H5)2], 130.4 [d, JPC = 60.3, P(i-C6H5)2], 128.9 [d, JPC
=
3
10.2, P(m-C6H5)2], 128.5 [d, JPC = 10.6, P(m-C6H5)2], 109.7 [d,
2JPC = 1.8, CCH(CH3)2], 94 (m, CH3–C), 89.7 (d, JPC = 2.8, o-
2
2
CH3C6H4), 85.9 (d, JPC = 5.4 m-CH3C6H4), 30.4 [s, CH(CH3)2],
21.4 [s, CH(CH3)2], 17.8 (s, CH3–C6H4). 31P{1H} NMR (CDCl3, –
3
50 °C): δ = 18.4 (d, JPP = 12.9, 1 P, Ru–P), 9.3–10.1 (m, 1P, P–
BH3). 11B{1H} NMR (CDCl3, –50 °C): δ = –37.3 (br). IR (nujol,
cm–1): ν
= 2448 (br), 2380 (sh). C36H39BCl2P2Ru·CH2Cl2
(801.37): calcd. C 55.46, H 5.16; found C 55.65, H 5.33.
˜
ν(BH)
Oxidation of [(η6-p-Cymene)RuCl2(η1-PPh2CH2PPh2)]: Orange
crystals of [(η6-p-cymene)RuCl2(η1-dppmO)] (3) suitable for X-ray
diffraction were obtained by recrystallisation of a reaction mixture
containing [(η6-p-cymene)RuCl2(η1-dppm)] over several months
from chloroform/pentane at 4 °C. Alternatively, [(η6-p-cymene)-
RuCl2(η1-dppm)] can be quantitatively converted to 2 by treatment
Preparation of [(η6-p-Cymene)RuCl2(η1-cis-PPh2CHCHPPh2)] (2):
A solution of [(η6-p-cymene)RuCl2]2 (0.160 g, 0.26 mmol) and
dppv (0.207 g, 0.26 mmol) in CH2Cl2 (50 mL) was stirred at room
temperature for 1 h. The product was obtained as an orange solid
following concentration and precipitation with diethyl ether. Yield
0.32 g (89%). Crystals suitable for X-ray crystallography were ob-
tained by recrystallisation from CH2Cl2/diethyl ether at 4 °C. 1H
NMR (CDCl3): δ = 8.1–8.2 [m, 4 H, RuP(o-C6H5)2 {31P@δ = 15.1}
with H2O2 in THF. H and 31P NMR spectroscopic data were in
1
agreement with the literature data.[17]
Preparation of [(η6-p-Cymene)RuCl2(η1-PPh2CCPPh2)] (5): To a
vigorously stirred solution of dppa (0.17 g, 0.43 mmol) in CH2Cl2
(15 mL, –78 °C) a solution of [(η6-p-cymene)RuCl2]2 (0.10 g,
0.16 mmol) in CH2Cl2 (15 mL) was added rapidly. Following an
additional 5 min stirring, the solvent was removed in vacuo at room
temperature. The resultant orange solid material was an ca.
0.4:1.0:0.7 mixture of 6/5/dppa as determined by 31P NMR spec-
troscopy. Successive recrystallisation from CH2Cl2/pentane at
–20 °C gave orange crystals of 5 in ca. 0.04 g (17%) yield. Crystals
of 6 suitable for X-ray analysis were obtained by slow diffusion of
pentane into a CH2Cl2 solution of the reaction mixture at room
temperature, whereas those of 5 were obtained after successive
recrystallisation of the reaction mixture from CH2Cl2/pentane at
3
2
3
δ = 8.15, d, JHH = 7.2], 7.54 (ddd, 3JHH = 13.5, JPH = 28.5, JPH
= 31.0 Hz, 1 H, RuPPh2CHCH), 7.38–7.44 [m, 2 H, RuP(p-C6H5)2],
7.30–7.38 [m, 4 H, RuP(m-C6H5)2], 7.18–7.24 [m, 2 H, pend-
P(p-C6H5)2], 7.12–7.18 [m, 4 H, pend-P(m-C6H5)2], 7.06 (ddd,
2
3
3JPH= 13.5, JHH = 4.0, JPH = 38.1 Hz, 1 H, CHCHPPh2), 6.85–
6.95 [m, 4 H, pend-P(o-C6H5)2 {31P@δ = –30.6} δ = 6.91 dd, JHH
= 1.2, JHH = 8.2 Hz], 5.26 (d, JHH = 5.1, 2 H, o-CH3C6H4), 5.15
(d, JHH = 6.0, 2 H, m-CH3C6H4), 2.55 [sept, JHH = 6.9 Hz, 1 H,
4
3
3
3
3
3
CH(CH3)2], 1.84 (s, 3 H, CH3–C6H4), 0.85 [d, JHH = 6.9 Hz, 6 H,
CH(CH3)2] ppm. 13C{1H} NMR (CDCl3): δ = 145.2 (dd, JPC
=
=
1
1
3
3
2
1
2
–20 °C. H NMR (CDCl3, –50 °C): δ = 7.97 [dd, JHH = 7.2, JPH
= 11.5, 4 H, RuP(o-C6H5)2], 7.6–7.9 [m, 4 H, pend-P(o-C6H5)2],
7.6, JPC = 17.4 Hz, CHCHPPh2), 140.3 (dd, JPC = 21.5, JPC
1
44.4 Hz, RuPPh2CHCH), 137.6 [d, JPC = 10.6, pend-P(i-C6H5)2],
3
1
4
2
7.3–7.6 [m, 12 H, P(m,p-C6H5)2], 5.31 (d, JHH = 5.9, 2 H, m-
134.2 [d, JPC = 45.6, RuP(i-C6H5)2], 133.5 [dd, JPC = 4.5, JPC
=
CH3C6H4), 5.22 (d, 3JHH = 5.6, 2 H, o-CH3C6H4), 2.80 [sept, 3JHH
2
9.7, RuP(o-C6H5)2], 132.5 [d, JPC = 18.4, pend-P(o-C6H5)2], 130.4
3
4
= 6.5, 1 H, CH(CH3)2], 1.85 (s, 3 H, CH3–C6H4), 1.04 [d, JHH
=
[d, JPC = 2.4, RuP(p-C6H5)2], 128.2–128.4 [obscured, pend-P(p-
6.6, 6 H, CH(CH3)2]. 13C{1H} NMR (CDCl3, –50 °C): δ = 133.7
[m, P(i-C6H5)2], 133.0–133.5 [m, P(o-C6H5)2], 131.0 [s, RuP(p-
C6H5)2], 130.2 [s, pend-P(p-C6H5)2], 129.3 [d, JPC = 8.0, P(m-
3
3
C6H5)2], 128.3 [d, JPC = 10.9, P(m-C6H5)2], 128.2 [d, JPC = 10.0,
2
P(m-C6H5)2], 108.6 [s, CCH(CH3)2], 93.7 (s, CH3–C), 90.3 (d, JPC
3
2
= 4.2, o-CH3C6H4), 85.2 (d, JPC = 6.0, m-CH3C6H4), 30.1 [s,
3
CH(CH3)2], 21.4 [s, CH(CH3)2], 17.4 (s, CH3–C6H4) ppm. 31P{1H}
C6H5)2], 128.4 [d, JPC = 10.9, P(m-C6H5)2], 109.6 [s, CCH-
(CH3)2], 96.1 (s, CH3–C), 89.9 (d, 2JPC = 3.5, o-CH3C6H4), 87.3 (d,
2JPC = 5.2, m-CH3C6H4), 30.5 [s, CH(CH3)2], 22.0 [s, CH-
(CH3)2], 17.9 (s, CH3–C6H4), the signals of RuPPh2CCPPPh2 were
not unambiguously located. 31P{1H} NMR (CDCl3, –50 °C): δ =
3
NMR (CDCl3): δ = 15.1 (d, JPP = 9.1 Hz, 1 P, Ru–P), –30.6 (d,
3JPP = 9.1 Hz, 1 P, pend-P) ppm. C36H36Cl2P2Ru (702.60): calcd.
C 61.54, H 5.16; found C 60.98, H 5.25.
Preparation of [(η6-p-Cymene)RuCl2(η1-cis-PPh2CHCHPPh2BH3)]
(2B): To a solution of 2 (0.100 g, 0.14 mmol) in CH2Cl2 (15 mL,
0 °C) a solution of BH3·THF in THF (0.12 mL of ca. 1.2 m,
0.14 mmol) was added dropwise. The solution was then warmed to
room temperature and stirred for 1 h. The solvent was then re-
moved in vacuo, and the solid washed with diethyl ether (25 mL)
and then recrystallised from CH2Cl2/pentane at –20 °C to give red
crystals suitable for X-ray diffraction. Yield: 0.05 g (50%) 1H NMR
(CDCl3, –50 °C): δ = 7.9–8.1 [m, 4 H, RuP(o-C6H5)2 {31P@δ =
3
0.4 (s, 1 P, Ru–P), –34.2 (d, JPP = 3.6, 1 P, pend-P). IR (nujol,
cm–1): ν
= 2110 (w).
˜
ν(CC)
Preparation of [(η6-p-Cymene)RuCl2(η1-PPh2CCPPh2BH3)] (5B):
To a solution of 5 (0.007 g, 0.01 mmol) in THF (2 mL, –78 °C) a
solution of BH3·THF in THF (0.01 mL of ca. 1.2 m, 0.012 mmol)
was added dropwise. The solution was then stirred for 1 h, and the
solvent was removed in vacuo as the solution warmed to room
temperature. Yield: quantitative (by 1H NMR). 1H NMR
(CDCl3, –50 °C): δ = 7.8–7.95 [m, 8 H, {31P@δ = 3.2} δ = 7.90, d,
3
3
18.4} δ = 7.97, d, JHH = 7.3], 7.69 (ddd, JHH = 16.2, JPH = 21.2,
JPH = 39.7, 1 H, PPh2CH), 7.2–7.5 [m, 16 H, P(o-C6H5)2BH3 and
P(m,p-C6H5)2], 6.86 (ddd, JPH = 4.7, 3JHH = 16.2, JPH = 36.9, 1 H,
RuP(o-C6H5)2, JHH = 7.2; {31P@δ = 5.8} δ = 7.88, d, P(o-C6H5)2-
3
3
3
BH3, JHH = 7.3], 7.3–7.65 [m, 12 H, P(m,p-C6H5)2], 5.36 (d, JHH
3
3
3
PPh2CH), 5.17 (d, JHH = 5.8, 2 H, m-CH3C6H4), 5.11 (d, JHH
=
= 6.0, 2 H, m-CH3C6H4), 5.28 (d, JHH = 5.7, 2 H, o-CH3C6H4),
3
3
5.9, 2 H, o-CH3C6H4), 2.62 [sept, JHH = 6.6, 1 H, CH(CH3)2],
2.75 [sept, JHH = 6.7, 1 H, CH(CH3)2], 1.86 (s, 3 H, CH3–C6H4),
3
3
1.75 (s, 3 H, CH3–C6H4), 0.83 [d, JHH = 6.7, 6 H, CH(CH3)2], 1.02 [d, JHH = 6.8, 6 H, CH(CH3)2], 1.0–1.6 [br., 3 H, BH3;
4770
www.eurjic.org
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2005, 4762–4774

Bis(phosphane)-Linked (η6-p-Cymene)ruthenium(ii)–Borane Compounds
FULL PAPER
2
{11B@δ = –37.3} δ = 1.30, d, JPH = 17.0]. 13C{1H} NMR RuP(m-C6H5Ј)2CCPPh2], 5.73–5.80 [m, 1 H, o-CH3C6H4Ј {31P@δ
2
3
3
(CDCl3, –50 °C): δ = 133.3 [d, JPC = 10.6, RuP(p-C6H5)2], 132.7
= 5.7} δ = 5.77, d, JHH = 6.3], 5.70 (d, JHH = 6.1, 1 H, m-
2
[s, P(p-C6H5)2BH3], 132.4 [d, JPC = 11.6, P(p-C6H5)2BH3], 131.4
CH3C6H4), 5.30–5.23 [m, 1 H, o-CH3C6H4 {31P@δ = 24.5} δ =
1
3
3
3
[s, RuP(p-C6H5)2], 130 [d, JPC ca. 60, P(i-C6H5)2], 129.6 [d, JPC
=
5.26, d, JHH = 6.5], 5.07 (d, JHH = 6.1, 1 H, m-CH3C6H4Ј), 2.80
11.3, P(m-C6H5)2BH3], 128.7 [d, 3JPC = 11.0, RuP(m-C6H5)2], 126.7 [sept, 3JHH = 6.9, 1 H, CH(CH3)2], 0.8–1.8 [br., 3 H, BH3; {11B@δ
1
1
2
3
[d, JPC = 64.6, P(i-C6H5)2], 110.4 [s, CCH(CH3)2], 104.5 [dd, JPC
= 65.7, 2JPC = 7.5, PCCP], 99.2 (dd, 1JPC = 89.4, 2JPC Ͻ 2, PCCP),
96.9 (s, CH3–C), 90.0 (d, JPC = 3.5, o-CH3C6H4), 87.4 (d, JPC
= –37.7} δ = 1.46, d, JPH = 16.2], 1.1–1.4 [m, JHH = 6.4, 9 H,
CH(CH3)2, CH(CH3Ј)2 and CH3–C6H4]. 13C{1H} NMR (CDCl3,
–50 °C): δ = 128–134 (poorly resolved, PPh), 133 [pend-P(o-C6H5)2
2
2
=
5.6, m-CH3C6H4), 30.5 [s, CH(CH3)2], 21.9 [s, CH(CH3)2], 17.9 (s, and pend-P(o-C6ЈH5)2], 132 [RuP(o-C6H5)3], 131 [CCH(CH3)2], 129
CH3–C6H4). 31P{1H} NMR (CDCl3, –50 °C): δ = 5.8 (br., 1 P, [RuP(m-C6ЈH5)2CCPPh2], 125.6 (m, RuPPh2CCPPh2), 99 (CH3–C),
PBH3), 3.2 (s, 1 P, RuP). 11B{1H} NMR (CDCl3): δ = –37.3 (br).
Preparation of [(η6-p-Cymene)RuCl(PPh3)(η1-PPh2CCPPh2)]PF6
99 (o-CH3C6H4), 97 (o-CH3C6ЈH4), 91 (m-CH3C6ЈH4), 90 (m-
CH3C6H4), 31.6 [s, CH(CH3)2], 21.8 [s, CH(CH3)2 or CH(CЈH3)2],
21.5 [s, CH(CЈH3)2 or CH(CH3)2], 15.1 (s, CH3–C6H4). 31P{1H}
(7):
A
suspension of [(η6-p-cymene)RuCl2(PPh3)] (0.70 g,
2
NMR (CDCl3): δ = 24.5 (d, JPP = 55.1, 1 P, Ru–PPh3), 7.8 (br., 1
1.23 mmol), [NH4]PF6 (0.20 g, 1.23) and dppa (0.49 g, 1.23 mmol)
in MeOH (150 mL) was heated at 35 °C for 3 h. The solvent was
removed in vacuo, and the residue taken up in a minimal amount
of CH2Cl2. A small amount of (unidentified) solid material was
removed by the addition of hexane and filtration. Removal of the
solvent gave an orange oil that solidified under high vacuum. Yield:
3
P, P–BH3), 5.7 (d, JPP = 55.1, 1 P, Ru–PPh2), –144.3 (sept, 1JPF
=
712.7, 1 P, PF6). 11B{1H} NMR (CDCl3): δ = –37.7 (br). IR (nujol,
cm–1): ν = ν(CC) not observed; ν(BH) 2393 (br). ESI-MS (MeOH)
˜
positive ion: m/z = 927 (100) [M – BH3]+, 941 (10) [M]+. ESI-MS
(CH2Cl2) positive ion: m/z = 927 (14) [M – BH3]+, 941 (100) [M]+.
ESI-MS2 (+941): m/z = 927 [M – BH3]+. ESI-MS3 (+941; +927):
m/z = 665 [M – PPh3 – BH3]+. ESI-MS (CH2Cl2) negative ion:
m/z = 145 (100) [PF6]–.
1
3
3
0.74 g (56%). H NMR (CDCl3): δ = 7.97 [dd, JHH = 7.2, JPH
=
12.3, 2 H, RuP(o-C6H5)2CCPPh2], 7.60–7.75 [m, 4 H, pend-P(o-
C6H5)2 and pend-P(o-C6H5Ј)2], 7.30–7.60 (m, 20 H, PPh), 7.10–
4
7.25 [m, 7 H, RuP(m-C6H5)3 and RuP(p-C6H5Ј)2], 6.92 [td, JPH
=
Preparation of [(η6-p-Cymene)RuCl2(η1-PPh2CH2PPh2BH3)] (1B):
2.9, 3JHH = 7.7, 2 H, RuP(m-C6H5Ј)2CCPPh2], 5.66 (d, 3JHH = 6.2,
To
a
solution of [(η6-p-cymene)RuCl2(η1-dppm)] (0.08 g,
1 H, m-CH3C6H4), 5.42–5.48 [m, 1 H, o-CH3C6H4Ј {31P@δ = 1.0} 0.116 mmol) in CH2Cl2 (5 mL, 0 °C) a solution of BH3·THF in
δ = 5.45, d, JHH = 6.3], 5.30–5.35 [m, 1 H, o-CH3C6H4 {31P@δ =
THF (0.12 mL of ca. 1 m, 0.12 mmol) was added dropwise. The
solution was then warmed to room temperature and stirred for
30 minutes. The product was isolated as an orange powder, follow-
ing concentration of the solution in vacuo and the addition of ex-
3
3
3
24.1} δ = 5.33, d, JHH = 6.4], 4.99 (d, JHH = 6.1, 1 H, m-
3
CH3C6H4Ј), 2.79 [sept, JHH = 6.9, 1 H, CH(CH3)2], 1.28 (s, 3 H,
3
3
CH3–C6H4), 1.23 [d, JHH = 6.4, 3 H, CH(CH3)2], 1.21 [d, JHH
=
6.4, 3 H, CH(CH3Ј)2]. 13C{1H} NMR (CDCl3): δ = 134.0 [d, JPC cess hexane. Yield: 0.06 g (78%). Orange crystals suitable for X-
2
2
= 9.6, RuP(o-C6H5)3], 133.6 [d, JPC = 21.8, pend-P(o-C6H5)2 or
ray diffraction were obtained by slow diffusion of pentane into a
chloroform solution of 1B at room temperature. 1H NMR (CDCl3):
δ = 7.9–8.1 [m, 4 H, RuP(o-C6H5)2; {31P@δ = 22.7} δ = 8.02, d,
2
pend-P(o-C6ЈH5)2], 133.0 [d, JPC = 21.0, pend-P(o-C6ЈH5)2 or
pend-P(o-C6H5)2], 132.5 [d, 1JPC = 47.9, P(i-C6H5)2], 132.4 [d, 2JPC
4
= 9.9, RuP(o-C6ЈH5)2], 131.7 [d, JPC = 2.3, P(p-C6H5)2], 131.3 [d,
3JHH = 7.1], 7.35–7.44 [m, 4 H, P(o-C6H5)2BH3; {31P@δ = 11.9} δ
2JPC = 10.8, RuP(o-C6H5)2], 130.9 [d, 4JPC = 2.3, P(p-C6H5)3], 130.5 = 7.39, d, JHH = 7.2], 7.1–7.35 [m, 12 H, P(m,p-C6H5)2], 5.23 (d,
3
[d, 1JPC = 47.4, P(i-C6H5)3], 130.2 [d, 4JPC = 2.9, P(p-C6H5)2], 129.7
3JHH = 5.6, 2 H, o-CH3C6H4), 5.11 (d, JHH = 6.0, 2 H, m-
3
3
2
3
[s, CCH(CH3)2], 129.4 [d, JPC = 11.3, pend-P(m-C6H5)2 or pend-
CH3C6H4), 3.92 (t, JPH = 10.4, 2 H, P–CH2–P), 2.49 [sept, JHH
3
3
P(m-C6ЈH5)2], 128.4 [d, JPC = 10.5, pend-P(m-C6ЈH5)2 or pend-
= 6.9, 1 H, CH(CH3)2], 1.79 (s, 3 H, CH3–C6H4), 0.87 [d, JHH =
P(m-C6H5)2], 129.1 [d, JPC = 11.2, RuP(m-C6H5)2], 128.4 [d, JPC 6.9, 6 H, CH(CH3)2], 0.1–1.2 [br., 3 H, BH3; {11B@δ = –38.4} δ =
3
3
3
2
2
= 10.5, RuP(m-C6H5)3], 128.3 [d, JPC = 11.9, RuP(m-C6ЈH5)2],
0.70, d, JPH = 15.6]. 13C{1H} NMR (CDCl3): δ = 133.9 [d, JPC
2
114.8 (m, RuPPh2CCPPh2), 100.3 (s, CH3–C), 99.0 (s, o-CH3C6H4
= 9.7, RuP(o-C6H5)2], 131.4 [d, JPC = 9.6, P(o-C6H5)2BH3], 131.2
2
2
4
4
and o-CH3CЈ6H4), 91.0 (d, JPC = 9.6, m-CH3C6H4), 90.4 (d, JPC [d, JPC = 2.5, RuP(p-C6H5)2], 130.5 [d, JPC = 2.3, P(p-C6H5)2-
3
= 9.4, m-CH3C6ЈH4), 31.3 [s, CH(CH3)2], 21.6 [s, CH(CH3)2 or BH3], 129.5–130.5 [m, P(i-C6H5)2], 128.5 [d, JPC = 10.2, P(m-
CH(CЈH3)2], 21.1 [s, CH(CЈH3)2 or CH(CH3)2], 15.5 (s, CH3– C6H5)2], 127.9 [d, 3JPC = 10.3, P(m-C6H5)2], 108.7 [s, CCH(CH3)2],
2
2
2
C6H4). 31P{1H} NMR (CDCl3): δ = 24.2 (d, JPP = 55.1, 1 P, Ru–
94.3 (s, CH3–C), 90.2 (d, JPC = 4.3, o-CH3C6H4), 85.5 (d, JPC =
3
2
PPh3), 1.0 (dd, JPP = 3.2, JPP = 55.1, 1 P, Ru–PPh2), –31.7 (d,
6.0, m-CH3C6H4), 30.0 [s, CH(CH3)2], 21.4 [s, CH(CH3)2], 17.2 (s,
3JPP = 4.9, 1 P, pend-PPh2), –144.4 (sept, JPF = 712.7, 1 P, PF6).
CH3–C6H4), 16.7 (dd, 1JPC = 19.4, 1JPC = 24.3, P–CH2–P). 31P{1H}
1
IR (nujol, cm–1): ν
= 2105 (w). ESI-MS (MeOH) positive ion:
NMR (CDCl3): δ = 22.7 (d, JPP = 29.2, 1 P, Ru–P), 11.9 (br., 1 P,
2
˜
ν(CC)
m/z = 533 (15) [M – PPh2CCPPh2]+, 665 (20) [M – PPh3]+, 927 P–BH3). 11B{1H} NMR (CDCl3): δ = –38.4 (br). IR (nujol, cm–1):
(100) [M]+. ESI-MS2 (+927): m/z = 665 [M – PPh3]+. ESI-MS nega-
tive ion: m/z = 145 [PF6]–. C54H49ClF6P4Ru·0.75CH2Cl2 (1136.09):
calcd. C 57.88, H 4.48; found C 57.54, H 4.53.
ν
= 2419 (br), 2389 (br). C35H39BCl2P2Ru·CH2Cl2 (789.36):
˜
ν(BH)
calcd. C 54.78, H 5.24; found C 55.24, H 5.26.
Preparation of [(η6-p-Cymene)RuCl2(η1-PPh2CH2CH2PPh2BH3)]
(8B): To a solution of dppe (0.104 g, 0.26 mmol) in CH2Cl2 (10 mL,
0 °C) a solution of [(η6-p-cymene)RuCl2]2 (0.100 g, 0.16 mmol) in
CH2Cl2 (5 mL) followed, ca. 1 min later, by a solution of BH3·THF
in THF (0.16 mL of ca. 1.2 m, 0.19 mmol)] were added rapidly. The
solution was then warmed to room temperature and stirred for 1 h.
The solvent was then removed in vacuo, and the residue extracted
with toluene (25 mL). Further [(η6-p-cymene)RuCl2(μ-dppe)-
Preparation
of
[(η6-p-Cymene)RuCl(PPh3)(η1-PPh2CCPPh2-
BH3)]PF6 (7B): To a solution of 7 (0.150 g, 0.12 mmol) in THF
(25 mL, –78 °C) a solution of BH3·THF in THF (0.10 mL of ca.
1.2 m, 0.12 mmol) was added dropwise. The solution was then
stirred for 1 h. The solvent was removed in vacuo as the solution
warmed to room temperature, the residue washed with diethyl ether
(2×20 mL) and then dried in vacuo. Yield: 0.095 g (78%). 1H
NMR (CDCl3): δ = 8.03 [dd, 3JHH = 7.6, 3JPH = 12.4, 2 H, RuP(o- RuCl2(η6-p-cymene)] could be separated from the reaction mixture
3
C6H5)2CCPPh2], 7.94 [dd, 3JHH = 7.4, JPH = 12.3, 2 H, pend-P(o-
by recrystallisation from CH2Cl2/pentane, at –20 °C. Purification
3
3
C6H5)2], 7.88 [dd, JHH = 7.4, JPH = 12.1, 2 H, pend-P(o-C6H5Ј)2], of the remaining material by preparative TLC (acetone/CH2Cl2,
4
3
7.1–7.7 (m, 27 H, PPh), 7.00 [td, JPH = 2.6, JHH = 7.6, 2 H,
1:11), extracting the first orange band with acetone, give the pure
Eur. J. Inorg. Chem. 2005, 4762–4774
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4771

A. B. Chaplin, R. Scopelliti, P. J. Dyson
FULL PAPER
product. Yield: 0.02 g (19%/BH3, 10%/Ru). Orange crystals suit-
product was then precipitated by the addition of hexane, filtered,
washed with hexane (ca. 20 mL) and dried in vacuo. Yield 1.30 g
able for X-ray diffraction were obtained by recrystallisation of 8B
1
from CH2Cl2/pentane at –20 °C. H NMR (CDCl3): δ = 7.68–7.78
(83%). 1H NMR (CDCl3):
δ
=
7.4–7.7 [m, 14 H,
[m, 4 H, RuP(o-C6H5)2; {31P@δ = 23.6} mЈ], 7.58–7.68 [m, 4 H,
P(o-C6H5)2BH3; {31P@δ = 18.2} mЈ], 7.58–7.8 [m, 12 H, P(m,p-
BH3PPh2(C6H4Br)], 0.8–1.8 [br., 3 H, BH3 {11B@δ = –38.0} δ =
1.27, d, JPH = 16.3]. 31P{1H} NMR (CDCl3): δ = 20.8 (d, JPB
Ϸ
2
1
3
3
1
C6H5)2], 5.19 (d, JHH = 5.7, 2 H, o-CH3C6H4), 5.12 (d, JHH
=
55). 11B{1H} NMR (CDCl3): δ = –38.0 (d, JPB Ϸ 55). IR (nujol,
6.0, 2 H, m-CH3C6H4), 2.7–2.9 [m, 2 H, CH2PPh2BH3; {31P@δ =
cm–1): ν
= 2385 (br).
˜
ν(BH)
3
2
3
23.6} δ = 2.77, JHH = 4.2, JPC = 12.9], 2.58 [sept, JHH = 6.9, 1
H, CH(CH3)2], 2.2–2.4 [m, 2 H, RuPPh2CH2; {31P@δ = 18.2} δ =
Preparation of 1,4-PPh2C6H4PPh2BH3: To a solution of 1,4-
BrC6H4PPh2BH3 (0.60 g, 1.69 mmol) in THF (30 mL, –78 °C) a
solution of BuLi in hexane (1.1 mL, Ϸ 1.6 m, 1.7 mmol) followed
by ClPPh2 (0.32 mL, 1.78 mmol) were added dropwise. The solu-
tion was stirred for a further 20 minutes and then warmed to room
temperature. The product was precipitated as a white solid by con-
centration and then collected by filtration, washed with methanol
(2×10 mL) and dried in vacuo. Yield 0.61 g (73%). 1H NMR
(CDCl3): δ = 7.4–7.7 [m, 14 H, BH3PPh2(C6H4Br)], 0.8–1.8 [br., 3
3
2
2.29, JHH = 3.9, JPC = 13.2], 1.90 (s, 3 H, CH3–C6H4), 1.01 [d,
3JHH = 6.9, 6 H, CH(CH3)2], 0.3–1.2 [br., 3 H, BH3; {11B@δ =
–40.6} δ = 0.80, d, 2JPH = 16.0]. 13C{1H} NMR (CDCl3): δ = 133.6
1
2
[d, JPC = 42.6, P(i-C6H5)2], 133.2 [d, JPC = 9.0, RuP(o-C6H5)2],
1
4
132.2 [d, JPC = 9.4, P(o-C6H5)2BH3], 131.1 [d, JPC = 2.2, P(p-
C6H5)2BH3], 130.9 [d, 4JPC = 2.2, RuP(p-C6H5)2], 128.5–129.1 [ob-
2
scured, P(i-C6H5)2], 128.7 [d, JPC = 10.0, P(m-C6H5)2], 128.6 [d,
1JPC = 9.5, P(m-C6H5)2], 109.5 [s, CCH(CH3)2], 95.7 (s, CH3–C),
89.8 (d, 2JPC = 4.0, o-CH3C6H4), 85.9 (d, 2JPC = 5.6, m-CH3C6H4),
2
H, BH3 {11B@δ = –38.0} δ = 1.27, d, JPH = 16.3]. 31P{1H} NMR
(CDCl3): δ = 20.8 (br., 1 P, PPh2BH3), –4.9 (s, 1 P, pend-PPh2).
1
30.1 [s, CH(CH3)2], 21.8 [s, CH(CH3)2], 21.7 (d, JPC = 29.8,
11B{1H} NMR (CDCl ): δ = –38.0 (br). IR (nujol, cm–1): ν
=
˜
1
3
ν(BH)
CH2PPh2BH3), 20.0 (d,, JPC = 36.9), 17 RuPPh2CH2.6 (s, CH3–
2398 (br).
C6H4). 31P{1H} NMR (CDCl3): δ = 23.6 (d, JPP = 42.8, 1 P, Ru–
3
P), 18.2 (br., 1 P, P–BH3). 11B{1H} NMR (CDCl3): δ = –40.6 (br).
Preparation of [(η6-p-Cymene)RuCl2(η1–1,4-PPh2C6H4PPh2BH3)]
(10): A solution of [(η6-p-cymene)RuCl2]2 (0.20 g, 0.33 mmol) and
1,4-PPh2C6H4PPh2BH3 (0.30 g, 0.65 mmol) in CH2Cl2 was stirred
at room temperature for 1 h. After concentration to ca. 25 mL the
product was precipitated with hexane. The orange solid was col-
lected by filtration, washed with hexane (3×10 mL) and dried in
IR (nujol, cm–1): ν
= 2370 (br).
˜
ν(BH)
Preparation of [(η6-p-Cymene)RuCl2(η1-PPh2C5H4FeC5H4PPh2-
BH3)] (9B): To a solution of dppf (0.145 g, 0.26 mmol) in CH2Cl2
(10 mL, 0 °C ice slurry) a solution of [(η6-p-cymene)RuCl2]2
(0.100 g, 0.16 mmol) in CH2Cl2 (5 mL) followed, ca. 1 min later, by
a solution of BH3·THF in THF (0.16 mL of ca. 1.2 m, 0.19 mmol)
were added. The solution was then warmed to room temperature
and stirred for 1 h, and the solvent was removed in vacuo. Extrac-
tion of the solid with toluene (40 mL) followed by recrystallisation
of this extract from CH2Cl2/pentane at –20 °C gave the product as
a orange solid. Yield: 0.11 g (61% /BH3, 37% /Ru). Further purifi-
cation is achieved by preparative TLC (acetone/CH2Cl2, 1:10 ), ex-
1
vacuo. Yield: 0.41 g (82%). H NMR (CDCl3): δ = 7.79–7.93 [m,
6 H, RuPPh2(o-C6H4PPh2BH3) and RuP(o-C6H5)2; {31P@δ = 24.9}
3
3
δ = 7.89, dd, 2 H, RuPPh2(o-C6H4PPh2BH3), JPH = 1.2, JHH
=
4
3
8.3 Hz; δ = 7.85, dd, 4 H, RuP(o-C6H5)2, JHH = 1.5, JHH = 7.9],
7.52–7.6 [m, 4 H, P(o-C6H5)2BH3; {31P@δ = 20.5} δ = 7.56, dd,
3
4JHH
=
1.4, JHH
=
8.3], 7.3–7.52 [m, 14 H, RuPPh2(m-
3
C6H4PPh2BH3) and P(m,p-C6H5)2], 5.22 (d, JHH = 6.1, 2 H, m-
CH3C6H4), 5.02 (d, 3JHH = 5.6, 2 H, o-CH3C6H4), 2.85 [sept, 3JHH
1
tracting the first orange band with acetone. H NMR (CDCl3): δ
3
= 7.7–7.8 [m, 4 H, RuP(o-C6H5)2; {31P@δ = 18.5} δ = 7.77, dd,
= 6.9, 1 H, CH(CH3)2], 1.88 (s, 3 H, CH3–C6H4), 1.11 [d, JHH
=
6.9, 6 H, CH(CH3)2], 0.6–1.76 [br., 3 H, BH3; {11B@δ = –38.1} δ
3
4JHH = 1.4, JHH = 7.7], 7.3–7.5 [m, 16 H, P(o-C6H5)2BH3 and
= 1.23, d, JPH = 16.3]. 13C{1H} NMR (CDCl3): δ = 137.1 [dd,
2
P(m,p-C6H5)2], 5.17 (d, 3JHH = 5.8, 2 H, o-CH3C6H4), 5.10 (d, 3JHH
= 6.1, 2 H, m-CH3C6H4), 4.45–4.50 [m, 2 H, (m-C5H4)PPh2BH3],
4.32–4.37 [m, 2 H, (o-C5H4)PPh2BH3], 4.10–4.15 [m, 2 H, RuP-
Ph2(o-C5H4)], 4.80–4.86 [m, 2 H, RuPPh2(m-C5H4)], 2.53 [sept,
3JHH = 6.9, 1 H, CH(CH3)2], 1.78 (s, 3 H, CH3–C6H4), 0.94 [d,
3JHH = 7.0, 6 H, CH(CH3)2], 0.7–1.5 [br., 3 H, BH3; {11B@δ =
–38.5} δ = 1.13, d, 2JPH = 16.4]. 13C{1H} NMR (CDCl3): δ = 136.8
RuPPh2(i-C6H4PPh2BH3), 4JPC = 2.3, 1JPC = 44.1], 134.4 [m, RuP-
2
Ph2(o-C6H4PPh2BH3)], 134.3 [d, JPC = 9.7, RuP(o-C6H5)2], 133.4
[d, JPC = 45.0, P(i-C6H5)2], 132.1 [m, RuPPh2(m-C6H4PPh2BH3)],
1
4
1
131.2 [dd, JPC = 2.2, JPC = 56.2, RuPPh2(p-C6H4PPh2BH3)],
4
4
131.4 [d, JPC = 2.3, P(p-C6H5)2BH3], 130.7 [d, JPC = 2.2, RuP(p-
3
1
C6H5)2], 128.8 [d, JPC = 10.3, P(m-C6H5)2], 128.4 [d, JPC = 58.2,
P(i-C6H5)2], 128.3 [d, 3JPC = 9.9, P(m-C6H5)2], 111.4 [d, 2JPC = 3.4,
1
[d, JPC = 47.1, RuP(i-C6H5)2], 133.8 [d, 2JPC = 9.5, RuP(o-C6H5)2],
2
2
1
CCH(CH3)2], 96.2 (s, CH3–C), 89.0 (d, JPC = 3.0, o-CH3C6H4),
132.5 [d, JPC = 9.7, P(o-C6H5)2BH3], 131.0 [d, JPC = 59.2, P(i-
2
4
3
87.3 (d, JPC = 5.5, m-CH3C6H4), 30.3 [s, CH(CH3)2], 21.8 [s,
C6H5)2BH3], 130.9 [d, JPC = 2.3, RuP(p-C6H5)2], 130.2 [d, JPC
2.1, P(p-C6H5)2], 128.4 [d, JPC = 10.2, P(m-C6H5)2], 127.7 [d, JPC
= 9.7, P(m-C6H5)2], 109.7 [s, CCH(CH3)2], 95.1 (s, CH3–C), 90.4
=
CH(CH3)2], 17.8 (s, CH3–C6H4). 31P{1H} NMR (CDCl3): δ = 24.9
3
3
(s, 1 P, Ru–P), 20.5 (br., 1 P, P–BH3). 11B{1H} NMR (CDCl3): δ
=
–38.1 (br). IR (nujol, cm–1):
ν
˜
=
2372 (br).
2
2
ν(BH)
(d, JPC = 4.2, o-CH3C6H4), 85.9 (d, JPC = 6.0, m-CH3C6H4),
C40H41BCl2PRu·1/3CH2Cl2 (794.81): calcd. C 60.95, H 5.28; found
3
2
76.53 [d, JPC = 7.4, (m-C5H4)PPh2BH3], 76.49 [d, JPC = 10.0,
3
C 60.78, H 5.19.
RuPPh2(o-C5H4)], 73.3 [d, JPC = 9.8, RuPPh2(m-C5H4)], 72.5 [d,
2JPC = 7.5, (o-C5H4)PPh2BH3], 69.0 [d, JPC = 67.4, RuPPh2(i-
1
X-ray Crystallography: Relevant details about the structure refine-
ments are given in Table 2 and Table 3. Selected geometrical pa-
rameters are included in the captions of Figure 3, Figure 4, Fig-
ure 6, Figure 7, Figure 10, Figure 11 and Figure 12. Data collection
for the X-ray structure determinations for compounds 2, 3, 5, 2B
and 8B were performed with a four-circle Kappa goniometer
equipped with an Oxford Diffraction KM4 Sapphire CCD at
140(2) K. For compounds 6 and 1B diffraction data were collected
with a mar345 IPDS instrument at 140(2) K. Data reduction was
performed using CrysAlis RED.[25] Structure solutions were solved
by direct methods using SIR92 (8B),[26] SIR97 (2, 6, 1B),[27] or
C5H4)], 29.9 [s, CH(CH3)2], 21.7 [s, CH(CH3)2], 17.0 (s, CH3–
C6H4); the signal of (i-C5H4)PPh2BH3 was not unambiguously lo-
cated. 31P{1H} NMR (CDCl3): δ = 18.5 (s, 1 P, Ru–P), 15.8 (br., 1
P, P–BH3). 11B{1H} NMR (CDCl3): δ = –38.5 (br). IR (nujol,
cm–1): ν
= 2373 (br).
˜
ν(BH)
Preparation of 1,4-BrC6H4PPh2BH3: To
a solution of 1,4-
BrC6H4PPh2 (1.50 g, 4.40 mmol) in THF (50 mL, 0 °C) a solution
of BH3·THF in THF (3.7 mL, ca. 1.2 m, 4.40 mmol) was added
dropwise. The solution was warmed to room temperature after
15 minutes and then concentrated to approximately 30 mL. The
4772
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© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2005, 4762–4774

Bis(phosphane)-Linked (η6-p-Cymene)ruthenium(ii)–Borane Compounds
FULL PAPER
SHELXTL[28] (3, 5), or by Patterson interpretation using
SHELXTL (2B).[28] Structure refinements were performed using
the SHELXTL software package for all compounds. An empirical
absorption correction (DELABS)[29] was applied to all data sets
except for that of 3. The structures of all compounds were refined
using full-matrix least-squares on F2 with the exception of 3, which
was refined using full-matrix-block least-squares on F2. All non-
hydrogen atoms were refined anisotropically, with hydrogen atoms
placed in calculated positions using the riding model with the ex-
ception of the BH hydrogen atoms, which were located on the Fou-
Table 2. Crystal data and details of the structure determinations for 2, 3, 5 and 6.
2
3
5
6
CCDC
280165
C36H36Cl2P2Ru
702.56
280166
280167
280168
C46H50Cl2P2Ru2·2CHCl3
1176.58
monoclinic
P21/n
12.710(4)
11.4016(18)
17.294(5)
Chemical formula
Formula mass
Crystal system
Space group
a [Å]
b [Å]
c [Å]
C35H36Cl2OP2Ru·1.5CHCl3 C36H34Cl2P2Ru·3CHCl3
885.60
1058.65
monoclinic
P21/n
15.9347(10)
11.5059(10)
25.7256(15)
triclinic
triclinic
¯
¯
P1
P1
10.5479(7)
12.5815(13)
12.8323(14)
81.579(9)°
82.482(8)°
85.270(7)°
1666.6(3)
2
1.400
720
0.750
140(2)
15.4477(11)
22.0211(12)
25.5063(12)
72.314(5)°
85.723(5)°
88.496(5)°
8243.4(8)
8
1.427
3592
0.907
140(2)
α
β
γ
98.777(5)°
101.06(2)°
V [Å3]
4661.4(6)
4
1.509
2128
1.063
140(2)
0.71073
26017
7835
2459.6(11)
2
1.589
1188
1.147
140(2)
0.71073
14479
4336
Z
Dcalcd. (g cm–3)
F(000)
μ [mm–1]
Temp. [K]
Wavelength [Å]
Measd. reflns.
Unique reflns.
0.71073
9849
5142
0.71073
49686
25535
Unique reflns. [I Ͼ 2σ(I)] 3659
12102
5586
3513
No. of data / restraints /
5142 / 0 / 373
25535 / 90 / 1706
7835 / 12 / 518
4336 / 3 / 284
parameters
R[a] [I Ͼ 2σ(I)]
0.0463
0.1066
0.923
0.0686
0.1991
0.912
0.0593
0.1708
1.060
0.0452
0.1023
1.065
[a]
wR2 (all data)
GoF[b]
[a] R = Σ||Fo| – |Fc||/Σ|Fo|, wR2 = {Σ[w(Fo – Fc ) ]/Σ[w(Fo2)2]}1/2. [b] GoF = {Σ[w(Fo – Fc ) ]/(n – p)}1/2 where n is the number of data
and p is the number of parameters refined.
2
2 2
2
2 2
Table 3. Crystal data and details of the structure determinations for 1B, 2B and 8B.
1B
2B
8B
CCDC
Empirical formula
Formula mass
280169
C35H39BCl2P2Ru·CHCl3
823.75
280170
C36H39BCl2P2Ru·CH2Cl2
801.32
280171
C36H41BCl2P2Ru·2CH2Cl2
888.26
Crystal system
Space group
monoclinic
C2/c
monoclinic
P21/c
triclinic
P1
¯
a [Å]
b [Å]
c [Å]
α
39.660(17)
11.024(3)
18.413(10)
14.5111(8)
16.6311(10)
17.1449(9)
8.7826(6)
14.5506(15)
16.754(2)
81.354(9)°
88.283(8)°
80.581(7)°
2088.2(4)
2
1.413
908
0.862
140(2)
β
γ
111.29(7)°
114.847(5)°
V [Å3]
7501(6)
8
1.459
3360
0.885
140(2)
0.71073
23670
6594
3754.7(4)
4
1.418
1640
0.813
140(2)
0.71073
21520
6295
Z
Dcalcd. (g cm–3)
F(000)
μ [mm–1]
Temp. [K]
Wavelength [Å]
Measd. reflns.
Unique reflns.
Unique reflns. [I Ͼ 2σ(I)]
0.71073
12575
6465
3801
5483
4171
No. of data / restraints / parameters 6594 / 74 / 450
6295 / 6 / 420
0.0390
0.1057
1.050
6465 / 12 / 447
0.0516
0.1326
R[a] [I Ͼ 2σ(I)]
0.0781
0.2331
0.993
[a]
wR2 (all data)
GoF[b]
0.937
[a] R = Σ||Fo| – |Fc||/Σ|Fo|, wR2 = {Σ[w(Fo – Fc ) ]/Σ[w(Fo2)2]}1/2. [b] GoF = {Σ[w(Fo – Fc ) ]/(n – p)}1/2 where n is the number of data
2
2 2
2
2 2
and p is the number of parameters refined.
Eur. J. Inorg. Chem. 2005, 4762–4774
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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4773

A. B. Chaplin, R. Scopelliti, P. J. Dyson
FULL PAPER
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rier difference map and then constrained to equal BH bond lengths
and H–B–H angles. Disorder in the p-cymene ring in complex 1B
was satisfactorily modeled by splitting the isopropyl moiety (with
constrained geometries) over two sites, constraining the ring and
restraining the atomic displacement parameters of the ring using
SIMU and ISOR commands. Some of the solvent molecules in 3,
5 and 6 were constrained or split over multiple sites. It was also
necessary to restrain the atomic displacement parameters of some
atoms in the structures of 3, 5, and 8B. Graphical representations
of the structures were made with Diamond.[30] CCDC-280165–
280171 contain the supplementary crystallographic data for this
paper (see Table 2 and Table 3). These data can be obtained free
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Acknowledgments
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We thank the New Zealand Foundation for Research, Science and
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EPFL and the Swiss National Science Foundation for financial
support.
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6
1
Alternatively, [(η -p-cymene)RuCl2(η -dppm)] can be quantita-
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ment with H2O2 in THF. 1H and 31P NMR spectroscopic data
were in agreement with the literature data.[17]
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6
Refluxing a solution of [(η -p-cymene)2Ru2(μ-Cl)3]PF6 and
dppa (1.5 equivalents) in CH2Cl2 for 2.5 h leads to a mixture
containing [(η6-p-cymene)RuCl2(η1-dppa){(μ-dppa)RuCl2(η6-
p-cymene)}]+ {31P NMR (CDCl3): δ = 29.0 (s, 1 P, RuCl2P),
2
2
22.4 (d, JPP = 61, 1 P, RuPPh2CCPPh2), 2.4 (d, JPP = 62, 1
3
P, RuPPh2CCPPh2RuCl2), –30.7 (d, JPP = 5, 1 P, pend-P).
ESI-MS (CH2Cl2) positive ion: m/z = +1365 [M]+}. Although
small amounts can be purified by preparative TLC (acetone/
CH2Cl2, 1:24), this complex undergoes an equilibration reac-
tion leading to a mixture containing [(η6-p-cymene)RuCl(η1-
dppa)2]+ {31P NMR (CDCl3): δ = 11.9 (s, 1 P, RuClP),
–31.3 (s, 1 P, pend-P). ESI-MS (CH2Cl2) positive ion: m/z =
+1059 [M]+} and [(η6-p-cymene)RuCl{(μ-dppa)RuCl2(η6-p-cy-
mene)}2]+ {31P NMR (CDCl3): δ = 24.4 (br., 1 P, RuP), 8.3
(br., 1 P, RuP). ESI-MS (CH2Cl2) positive ion: m/z = +1671
[M]+}.
Determined by 31P NMR of an aliquot taken from the solution
after 2 h, the solvent removed in vacuo and then the solid redis-
solved in CDCl3.
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Received: August 5, 2005
Published Online: October 25, 2005
4774
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Eur. J. Inorg. Chem. 2005, 4762–4774