Synthesis and structure of new (Polyphosphane)ruthenium complexes with the hemilabile ligand 2-(Diphenylphosphanyl)-1-methyl-1H-imidazole - An unexpected rearrangement of [RnCl2(PN)(PPh3)2]

Article abstract of DOI:10.1002/ejic.200300892

Several Ru^II complexes containing the potentially bidentate ligand 2-(diphenylphosphanyl)-1-methyl-1H-imidazole [PPh₂MeIm (PN)] have been synthesised and characterised. Reaction of the ligand with [RuCl ₂(PPh₃)₃] in different molar ratios led to the formation of the complexes trans,mer[RuCl₂(PPh₃) ₂(κ²-P,N-PPh₂MeIm)] (1), fac-[RuCl(PPh₃)(κ²-P,N-PPh₂MeIm) ₂]Cl (2a), mer-[RuCl(PPh₃)(κ²-PN-PPh ₂MeIm)₂]Cl (2b), fac-[RuCl(κ¹-P-PPh ₂MeIm)(κ2-P,N-PPh₂MeIm)₂]Cl (3a), and mer-[RuCl(κ¹-P-PPh₂MeIm)(κ²-PN- PPh₂MeIm)₂]Cl (3b). Complex 1 evolves in solution to 2a, 2b and the dinuclear species [(PPh₃)(κ¹-P-PPh ₂MeIm)ClRu(μ-Cl)₂Ru(PPh₃) (κ¹-P-PPh₂MeIm)Cl] (4a), [(PPh₃) ClRu(μ-Cl)₂(μ2-P,N-PPh₂MeIm)₂Ru(PPh ₃)Cl] (4b), and [(PPh₃)(κ²-P,N-PPh ₂MeIm) ClRu(μ-Cl)₂Ru(PPh₃) (κ²-P,N-PPh₂MeIm)Cl] (4c). It is proposed that the formation of the dinuclear derivatives involves an Ru-N bond-breaking step that demonstrates the hemilabile behaviour of the ligand. When 2 equiv. of the PN ligand were added to [RuCl₂(cod)(bpzm)] [cod = 1,5-cyclooctadiene, bpzm = bis(pyrazol-1-yl)methane], the complex cis-P-[RuCl₂(κ ¹-PPh₂MeIm)(κ²-PPh₂MeIm)] (5) was formed as the only product. The derivatives [Ru(κ²-PPh ₂MeIm)₃]X₂ [(X = PF₆ (6), BF ₄ (7)] were obtained upon treatment of [RuCl₂(arene)] ₂ (arene = p-cymene, benzene) with 2 equiv. of the corresponding silver salts and the PN ligand. Both the fac (6a, 7a) and mer (6b, 7b) forms were obtained. Two new hydride complexes were also synthesised: mer-[RuHClL ₂(κ²-PPh₂MeIm)] [L = PPh₃ (8) or κ¹-PN (9)] by reaction of the PN ligand with [RuHCl(PPh ₃)₃] or [RuHCl(cod)(bpzm)], respectively. The molecular structure of 4b and fac-7a was solved by an X-ray diffraction study. Complex 4b has a dinuclear structure with two chloride bridges and two head-to-tail PN bridges. The derivative fac-7a is mononuclear, Both enantiomers - A and A - were observed in the same unit cell. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.

Full text of DOI:10.1002/ejic.200300892

FULL PAPER
Synthesis and Structure of New (Polyphosphane)ruthenium Complexes with the
Hemilabile Ligand 2-(Diphenylphosphanyl)-1-methyl-1H-imidazole ؊ An
Unexpected Rearrangement of [RuCl2(PN)(PPh3)2]
[a]
[b]
[c]
[b]
´
´
Gustavo Espino, Felix A. Jalon, Miguel Maestro, Blanca R. Manzano,*
[a]
[a]
´
Mercedes Perez-Manrique, and Ana C. Bacigalupe
Keywords: Ruthenium / Hemilabile ligands / Hydride ligands / Phosphanes / N,P ligands
Several RuII complexes containing the potentially bidentate
octadiene, bpzm = bis(pyrazol-1-yl)methane], the complex
2-(diphenylphosphanyl)-1-methyl-1H-imidazole cis-P-[RuCl2(κ1-PPh2MeIm)(κ2-PPh2MeIm)] (5) was formed as
ligand
[PPh2MeIm (PN)] have been synthesised and characterised.
Reaction of the ligand with [RuCl2(PPh3)3] in different molar
ratios led to the formation of the complexes trans,mer-
[RuCl2(PPh3)2(κ2-P,N−PPh2MeIm)] (1), fac-[RuCl(PPh3)(κ2-
P,N-PPh2MeIm)2]Cl (2a), mer-[RuCl(PPh3)(κ2-P,N-PPh2Me-
Im)2]Cl (2b), fac-[RuCl(κ1-P-PPh2MeIm)(κ2-P,N-PPh2Me-
the only product. The derivatives [Ru(κ2-PPh2MeIm)3]X2
[(X = PF6 (6), BF4 (7)] were obtained upon treatment of [Ru-
Cl2(arene)]2 (arene = p-cymene, benzene) with 2 equiv. of the
corresponding silver salts and the PN ligand. Both the fac
(6a, 7a) and mer (6b, 7b) forms were obtained. Two new hy-
dride complexes were also synthesised: mer-[RuHClL2(κ2-
PPh2MeIm)] [L = PPh3 (8) or κ1-PN (9)] by reaction of the PN
ligand with [RuHCl(PPh3)3] or [RuHCl(cod)(bpzm)], respect-
ively. The molecular structure of 4b and fac-7a was solved
by an X-ray diffraction study. Complex 4b has a dinuclear
structure with two chloride bridges and two head-to-tail PN
bridges. The derivative fac-7a is mononuclear. Both enanti-
omers — ∆ and Λ — were observed in the same unit cell.
Im)2]Cl
(3a),
and
mer-[RuCl(κ1-P-PPh2MeIm)(κ2-PN-
PPh2MeIm)2]Cl (3b). Complex 1 evolves in solution to 2a, 2b
and the dinuclear species [(PPh3)(κ1-P-PPh2MeIm)ClRu(µ-
Cl)2Ru(PPh3)(κ1-P-PPh2MeIm)Cl] (4a), [(PPh3)ClRu(µ-Cl)2(µ2-
P,N-PPh2MeIm)2Ru(PPh3)Cl] (4b), and [(PPh3)(κ2-P,N-
PPh2MeIm)ClRu(µ-Cl)2Ru(PPh3)(κ2-P,N-PPh2MeIm)Cl] (4c).
It is proposed that the formation of the dinuclear derivatives
involves an Ru−N bond-breaking step that demonstrates the
hemilabile behaviour of the ligand. When 2 equiv. of the PN
( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
ligand were added to [RuCl2(cod)(bpzm)] [cod = 1,5-cyclo- Germany, 2004)
Introduction
This process allows the coordination of substrates such as
hydrogen or molecules that act as a hydrogen source, such
as alcohols.[9] A theoretical alternative to the complete de-
coordination of a tertiary phosphane is the partial decoor-
dination of a bidentate and hemilabile phosphane that
probably causes only a minor effect on the electronic sta-
bility of the catalyst. With this possibility in mind, we envis-
aged the reaction of typical precursors like [RuCl2(PPh3)3]
or [RuClH(PPh3)3] with 2-(diphenylphosphanyl)-1-methyl-
1H-imidazol[10] (PPh2MeIm; Scheme 1), in different molar
ratios, to obtain potential catalyst precursors with different
structures and nuclearities. In order to compare our results
and obtain complexes that are free of triphenylphosphane,
we also used as starting materials [RuCl2(cod)(bpzm)]
Ruthenium() derivatives containing tertiary phosphane
ligands are important precursors in catalytic processes, par-
ticularly hydrogenation.[1] For example, complexes of for-
mula [RuCl2Ln], [RuClHLn] (n ϭ 3, 4), [RuCl2(CO)L3] or
[RuClH(CO)L3] are efficient catalysts in the hydrogenation
of alkenes,[2] alkynes,[2,3] aromatic heterocycles[4] or hydro-
carbons,[5] aldehydes and ketones.[6] In many of these cata-
lytic processes, cycles involving the decoordination of phos-
phanes or chlorides are involved.[1,2] For instance,
[RuCl2(PPh3)3] is a classical starting point to give an active
catalyst through phosphane[7] or chloride[8] dissociation.
[a]
´
Departamento de Quımica, Facultad de Ciencias, Universidad
de Burgos,
Pza Misael Ban˜uelos s/n, 09001 Burgos, Spain
[b]
[c]
´
´
´
´
Departamento de Quımica Inorganica, Organica y Bioquımica,
Universidad de Castilla-La Mancha,
13071 Ciudad Real, Spain
`
´
Servicios Xerais de Apoio a Investigacion, Universidade da
Corun˜a,
Campus da Zapateira s/n, 15071 A Corun˜a, Spain
Scheme 1. PPh2MeIm ligand
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DOI: 10.1002/ejic.200300892
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New (Polyphosphane)ruthenium Complexes
FULL PAPER
[cod ϭ 1,5-cyclooctadiene, bpzm ϭ bis(pyrazol-1-yl)me- plex 1 shows a single absorption band at 326 cmϪ1, which
thane] and [RuCl2(p-cymene)]2 as halide precursors and is characteristic of ν(RuϪCl) with mutual trans-chloride
[RuClH(cod)(bpzm)] as a hydride.[11] In contrast to the ions.[14,15] The FABϩ mass spectrum is in complete agree-
widely used phosphane 2-(diphenylphosphanyl)pyridine,[12] ment with the expected fragmentation pattern and contains
the use of PPh2MeIm as a bidentate ligand offers a more a peak corresponding to the fragment [RuCl(PPh3)2(PN)]ϩ
strained bite angle. This situation can favour the partial de- at m/z ϭ 927, which is the result of chloride loss from 1. In
coordination of the phosphane group.
subsequent steps, the loss of PPh3 gives [RuCl(PPh3)(PN)]ϩ
(m/z ϭ 665), and [RuCl(PN)]ϩ (m/z ϭ 403). On the basis
of these data, the structure of 1, which must be present
as a mixture of enantiomers, is believed to be that shown
in Scheme 2.
Results and Discussion
The following discussion concerns the synthesis and
characterisation of the new RuII derivatives containing the
hemilabile ligand PPh2MeIm (PN). The discussion is di-
vided according to the Ru species used as the starting mate-
rial.
Reaction of PPh2MeIm with [RuCl2(PPh3)3] ؊ X-ray
structure of [(PPh3)ClRu(µ-Cl)2(µ2-P,N-
PPh2MeIm)2Ru(PPh3)Cl]·CH2Cl2
The reaction of [RuCl2(PPh3)3] with the ligand PN was
studied in different molar ratios and this led to the forma-
tion of different complexes containing either one, two or
three ligands bonded to the ruthenium centre. When
[RuCl2(PPh3)3] was heated under reflux with 1 equiv. of PN
in CH2Cl2 the polyphosphane complex 1 was isolated in
89% yield [Equation (1)].
[RuCl2(PPh3)3] ϩ PN Ǟ [RuCl2(PPh3)2(κ2-PN)] (1) ϩ PPh3
(1)
Scheme 2. Reaction scheme for the system [RuCl2(PPh3)3]/nPN
(n ϭ 1, 2, 3, 6)
The conductivity data indicate that 1 is a neutral mol-
ecule. The 31P{1H} NMR spectrum (in CDCl3; see Table 1)
of 1 consists of an AMX pattern with two cis 2J (2JA,M and
The reactions of [RuCl2(PPh3)3] with 2, 3 and 6 equiv. of
2JA,X) and one trans J (2JM,X) coupling constants. These the ligand PN were also investigated. These reactions led to
data are in agreement with a mer disposition of the three P the formation of four new complexes, as deduced from the
atoms. The high-field doublet of doublets [δ ϭ Ϫ22.2 ppm corresponding 31P{1H} NMR spectra. The results can be
(PX)] is consistent with the formation of a four-membered summarised as follows (see Scheme 2): (i) When the Ru/PN
chelate ring in the PN ligand.[13] The IR spectrum of com- ratio was 1:2, complex 1 was formed along with two new
2
Table 1. 31P{1H} NMR chemical shifts for the new complexes
Complex
Solvent
Spin system
δ [ppm]
PM or PB
J [Hz]
2JAM or JAB
2JAX
2JMX
2
PA
PX
mer-1
fac-2a
mer-2b
fac-3a
mer-3b
4a
CDCl3
CDCl3
CDCl3
CDCl3
CDCl3
CDCl3
CDCl3
CDCl3
AMX
AMX
AMX
AMX
AMX
AB
AM
AM
AM
A3
AMX
A3
AMX
AMX
AMX
43.70 dd
52.44 pt
58.30 pt
45.37 pt
52.20 pt
48.80 d
68.09 d
42.11 d
51.85 d
13.21 s
20.70 t
33.2 dd
7.55 pt
Ϫ5.87 dd
15.91 pt
Ϫ7.70 dd
44.57 d
19.43 d
Ϫ1.12 d
3.35 d
Ϫ22.21 dd
5.58 pt
Ϫ18.24 dd
3.78 pt
Ϫ13.80 dd
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ3.61[c] dd
Ϫ
Ϫ3.61[c] dd
Ϫ14.90 dd
Ϫ10.00 dd
29.00
36.01
31.73
32.02
31.31
36.13
36.63
25.32
32.02
Ϫ
26.93
Ϫ
26.91
32.03
32.11
32
322.15
27.51
304.02
32.03
312.81
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
290.52
Ϫ
290.53
285.02
293.11
28.2
26.3
33.6
28
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
26.91
Ϫ
4b
4c
5
[D6]acetone[a]
[D6]acetone
[D6]acetone
[D6]acetone
[D6]acetone
C6D6
fac-6a[b]
mer-6b[b]
fac-7a
mer-7b
mer-8
mer-9
Ϫ
3.67[c] dd
Ϫ
13.21 s
20.70 t
70.23 pt
58.30 pt
3.67[c] dd
53.82 dd
40.49 dd
26.92
29.73
26.91
C6D6
[a]
Ϫ
1
[c]
At Ϫ90 °C. [b] The signal for the PF6 counteranion appears at δ ϭ Ϫ143.2 (sept, JF,P ϭ 708 Hz) ppm. The assignment of PM and
PX could be reversed.
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B. R. Manzano et al.
FULL PAPER
complexes (2a and 2b). (ii) When the ratio was 1:3, complex PPh2MeIm)2]Cl. These compounds contain one PPh3
1 was not formed but 2a, 2b and a new complex (3a) were group, which can be removed by another molecule of PN
observed in the reaction medium. (iii) The reaction with a when larger amounts of the ligand are used. This change
ratio of 1:6 led to the formation of 2a, 2b, 3a and a new leads to complexes 3a and 3b and these are the correspond-
derivative (3b).
ing fac and mer isomers of stoichiometry [RuCl(κ1-P-
We were able to deduce the structures of the four new PPh2MeIm)(κ2-P,N-PPh2MeIm)2]Cl. The structures of the
complexes with the help of information obtained from a new derivatives, which are consistent with the data ob-
31P,31P COSY experiment in CDCl3 on a sample of the ma- tained, are shown in Scheme 2.
terial formed in the reaction with the 1:6 ratio, which con-
Attempts were made to obtain crystals of 1 from a di-
tained the four new derivatives (see Figure 1). The con- chloromethane/hexane mixture (1:1) in order to carry out
clusions reached can be summarised as follows: (i) The spin an X-ray structure determination. Unexpectedly, the crys-
system of each derivative fits an AMX pattern. (ii) Com- tals obtained corresponded to the dinuclear species
pounds 2a and 3a exhibit a fac-PPP disposition. (iii) Com- [(PPh3)ClRu(µ-Cl)2(µ2-P,N-PPh2MeIm)2Ru(PPh3)Cl] (4b)
pounds 2b and 3b exhibit a mer-PPP disposition. (iv) All as a dichloromethane solvate. The ORTEP plot of 4b is
of these new compounds have two four-membered chelate shown in Figure 2, a selection of bond lengths and angles
rings (PN ligand) and one monodentate phosphane ligand, are given in Table 2. Other crystallographic data are given
as deduced from the existence of two high-field signals and in the Exp. Sect. The complex has a dinuclear structure with
a low-field resonance for each derivative.
two chloride bridges and two other head-to-tail axial PN
From the point of view of stoichiometry, it seems reason- bridges. The two metal centres are in a slightly distorted
able that in the reaction with a 1:2 ratio, the replacement octahedral geometry as a consequence of the bridge strain,
of two PPh3 units by two PN ligands takes place with the which is exemplified by the N(1)ϪRu(1)ϪCl(1) (86.04°) and
concomitant loss of one chloride ligand from the ruthenium N(1)ϪRu(1)ϪCl(1A) (82.80°) angles. The two terminal po-
centre. In this case complexes 2a and 2b will be the fac and sitions for each of the ruthenium atoms are occupied by
mer isomers with the stoichiometry [RuCl(PPh3)(κ2-P,N- one Cl and one PPh3 ligand.
Figure 1. 31P,31P COSY spectrum (161.923 MHz) in CDCl3 at room temperature for a sample of the reaction between [RuCl2(PPh3)3]
and PMe2MeIm in a 1:6 ratio; * indicates free PN
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New (Polyphosphane)ruthenium Complexes
FULL PAPER
Figure 2. ORTEP plot of 4b, showing atom labelling; hydrogen atoms have been omitted for clarity
RuII(µ-Cl)2RuII bridges (but without an RuϪRu bond,
˚
Table 2. Selected bond lengths [A] and angles [°] for 4b·CH2Cl2 and
fac-7a·(CH3)2CO with estimated standard deviations in parenth-
eses
[11b,16]
˚
3.68Ϫ3.91 A)
and those found in derivatives that do
2
2
˚
contain an RuϪRu bond {e.g. 2.93 A in [RuCl2(µ -Cl2)(µ -
dppm)RuCl2]}.[17] The presence of the two additional PCN
bridges can lead to shortening of this distance, a situation
that has been observed in other dinuclear Ru derivatives
with additional short bridges.[18]
4b·CH2Cl2
Ru(1)ϪN(1)
Ru(1)ϪP(1)
Ru(1)ϪP(2)
Ru(1)ϪCl(1)
Ru(1)ϪCl(2)
Ru(1)ϪCl(1A)
P(1)ϪC(25)
P(1)ϪC(19)
P(1)ϪC(33)
P(2)ϪC(13)
P(2)ϪC(1)
2.146(3)
N(1)ϪRu(1)ϪP(1)
164.83(7)
93.92(7)
100.81(3)
86.04(7)
89.47(3)
93.40(3)
87.43(7)
95.57(3)
92.04(3)
171.77(3)
82.80(7)
82.76(3)
174.72(3)
90.50(3)
83.71(3)
89.50(3)
2.2929(9) N(1)ϪRu(1)ϪP(2)
2.2967(9) P(1)ϪRu(1)ϪP(2)
2.3878(8) N(1)ϪRu(1)ϪCl(1)
2.3987(8) P(1)ϪRu(1)ϪCl(1)
2.4387(8) P(2)ϪRu(1)ϪCl(1)
In addition, the distances between each of the chloride
bridging ligands and each of the ruthenium atoms are
˚
asymmetric, with d[Ru(1)ϪCl(1)]
ϭ
2.3878
A
and
˚
d[Ru(1A)ϪCl(1)] ϭ 2.4387 A. This indicates a greater
elongation of the µ-ClϪRu bonds trans to PPh3 in compari-
son to those trans to ClϪ. This situation is in keeping with
the higher trans influence of a P-donor ligand than a chlo-
ride ligand.[18,19]
1.832(3)
1.840(3)
1.861(3)
1.827(3)
1.848(3)
1.852(3)
N(1)ϪRu(1)ϪCl(2)
P(1)ϪRu(1)ϪCl(2)
P(2)ϪRu(1)ϪCl(2)
Cl(1)ϪRu(1)ϪCl(2)
N(1)ϪRu(1)ϪCl(1A)
P(1)ϪRu(1)ϪCl(1A)
P(2)ϪRu(1)ϪCl(1A)
Cl(1)ϪRu(1)ϪCl(1A)
Cl(2)ϪRu(1)ϪCl(1A)
Ru(1)ϪCl(1)ϪRu(1A)
P(2)ϪC(7)
In order to understand the unexpected transformation of
complex 1, we monitored the evolution of a CDCl3 solution
of 1 during 3 d by 31P{1H} NMR spectroscopy. This experi-
ment indicated that 1 undergoes a slow rearrangement in
solution. The final 31P{1H} NMR spectrum is very compli-
cated and shows the presence of several complexes (see Fig-
ure 3). A 31P,31P COSY experiment allowed each group of
coupled signals to be correlated and indicated five indepen-
dent spin systems and a singlet.
In this spectrum the resonances of 2a and 2b can be seen
along with those of 4b, which corresponds to an AM spin
system (two doublets at δ ϭ 19.43 and 68.09 ppm). The
former of these signals can be assigned to a bridging coordi-
nation mode of the PN ligand on the basis of literature
data.[20] The second doublet must correspond to coordi-
fac-7a·(CH3)2CO
Ru(1)ϪN(6)
Ru(1)ϪN(4)
Ru(1)ϪN(2)
Ru(1)ϪP(1)
Ru(1)ϪP(3)
Ru(1)ϪP(2)
2.140(2)
2.160(2)
2.173(2)
N(2)ϪRu(1)ϪP(1)
N(4)ϪRu(1)ϪP(2)
N(6)ϪRu(1)ϪP(3)
68.74(6)
68.59(6)
69.04(7)
105.50(18)
104.58(18)
105.28(18)
2.2954(8) N(2)ϪC(13)ϪP(1)
2.2990(9) N(6)ϪC(45)ϪP(3)
2.2995(8) N(4)ϪC(29)ϪP(2)
˚
The Ru(1)ϪRu(1A) distance is only 3.398 A and is inter- nated PPh3. Two additional spin systems can also be ob-
mediate between those typically observed in complexes with served in the spectrum. Both of these have an AM pattern
Eur. J. Inorg. Chem. 2004, 2542Ϫ2552
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B. R. Manzano et al.
FULL PAPER
Figure 3. 31P{1H} NMR spectrum (161.923 MHz) in CDCl3 at room temperature for a sample of 1 after 3 d in solution
with coupling constants typical of two P atoms in a cis dis-
Although we do not have direct proof, we think that a
position. The pair of signals for one complex, 4a, have reasonable mechanism for the dimerisation of 1 to 4a, 4b
chemical shifts that do not correspond to either a chelating and 4c is that shown in Scheme 4. This process would be
or bridging coordination of the PN ligand. Consequently, favoured by the hemilabile character of the PN ligand and
the PN ligand must exhibit monodentate coordination. One may involve the following steps: (i) Dissociation of one
of the resonances of the other derivative, 4c, indicates a PPh3 ligand. (ii) Partial dissociation of the PN ligand as a
chelating coordination. Considering this information we consequence of the strain in the four-membered ring and
propose the structures indicated in Scheme 3 for complexes formation of two chloride bridges. Such a change leads to
4a and 4c. These structures are also reasonable in terms of the formation of 4a. The spontaneous dissociation of one
the evolution of complex 1 after the loss of one PPh3 ligand PPh3 group[22] and the consequent formation of chloride
(see below). In the NMR spectrum there is also an intense bridges[21b,23] has been reported for [RuCl2(PPh3)3]. The co-
singlet at δ ϭ 30.3 ppm, which can be assigned to ordination of the N atom to occupy the vacancy on each
[RuCl2(PPh3)3] — probably in equilibrium with free metal centre could take place in two ways, either to produce
PPh3.[21] According to the stoichiometry of the derivatives PN bridges between the two metal centres to give 4b, or to
formed from 1, both species must exist in the reaction me- regenerate a four-membered chelate ring on each metal
dium (Scheme 3).
atom to give 4c.
Scheme 3. Products formed after the evolution of 1 in solution
Scheme 4. Mechanism proposed for the dimerisation of 1
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New (Polyphosphane)ruthenium Complexes
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Reaction of PPh2MeIm with [RuCl2(cod)(bpzm)]
Table 1 for the 31P NMR spectroscopic data). The FABϩ
spectrum is consistent with the proposed formulation, as a
peak corresponding to the cation of 3 is observed at m/z ϭ
935. The rest of the peaks are in agreement with the loss of
a chloride ion and two PN ligands in successive steps (see
Exp. Sect.).
In the previous reactions between the PN ligand and
[RuCl2(PPh3)3] we obtained a rich variety of products that
included not only mononuclear species with different
amounts of the PN ligand but also dinuclear derivatives.
It is clear from these results that competition between the
incoming ligand and PPh3 is always present and frequently
leads to the formation of product mixtures. Even when 6
equiv. of the PN ligand were used, the products that do
not contain PPh3 (3a, 3b) were formed along with those
containing 1 equiv. of the phosphane (2a, 2b). Given these
findings, we decided to use a starting material that did not
contain the phosphane ligand and incorporated weakly co-
ordinating ligands — [RuCl2(cod)(bpzm)] [cod ϭ 1,5-cyclo-
octadiene, bpzm ϭ bis(pyrazol-1-yl)methane]. It has been
shown that both cod and bpzpm ligands are prone to re-
placement by PN donor ligands.[11a] When 2 equiv. of
PPh2MeIm were added to a suspension of this compound
and the mixture heated under reflux in THF, the complex
cis-P-[RuCl2(κ1-P-PPh2MeIm)(κ2-P,N-PPh2MeIm)] (5) was
obtained as the only product [Equation (2)].
Reaction of PPh2MeIm with [RuCl2(p-cymene)]2 ؊ X-ray
Structure of fac-[Ru(κ2-P,N-PPh2MeIm)3](BF4)2·(CH3)2CO
Another goal of our study was the synthesis of deriva-
tives of the type [Ru(PN)3]X2, with three chelate ligands.
Such complexes would be expected to be chiral[24] and, con-
sidering the hemilabile character of the PN ligand, they
could be interesting starting materials in catalytic or stoi-
chiometric processes.[25] We succeeded in the synthesis of
these compounds by using [RuCl2(arene)]2 (arene ϭ p-cy-
mene, benzene) as starting materials and adding silver salts
to remove the chloride ions. In this way, the complexes
[Ru(κ2-P,N-PPh2MeIm)3]X2 [X ϭ PF6 (6) and BF4 (7)] were
isolated after the addition of the ligand PPh2MeIm to the
solution obtained by treatment of a suspension of [RuCl2(a-
rene)]2 in MeOH with AgPF6 or AgBF4, respectively, at
room temperature [Equation (3)]. The same products were
also formed upon treatment of [RuCl2(cod)(bpzm)] with the
silver salt and the PN ligand, but in this case the reaction
led to a mixture of derivatives. Consequently, the reaction
outlined in Equation (3) is more convenient.
[RuCl2(cod)(bpzm)] ϩ 2 PN Ǟ
(2)
cis-P-[RuCl2(κ1-PN)(κ2-PN)] (5) ϩ cod ϩ bpzm
The 1H NMR spectrum at low temperature does not
show any evidence of the presence of bpzm or cod ligands
and signals for only two kinds of PN ligand were observed.
The corresponding 31P{1H} NMR spectrum ([D6]acetone)
at room temperature contains two broad signals that must
be due to some kind of fluxional process. In an attempt to
obtain more information on the structure of the complex,
a 31P{1H} NMR spectrum was recorded at low temperature
(Ϫ90 °C) and an AM pattern was observed [δ ϭ 3.35 (d)
and 51.85 (d) ppm]. The high-field resonance can be as-
[RuCl2(arene)]2 ϩ 4 AgX ϩ 6 PN Ǟ
2 [Ru(κ2-PN)3]X2 ϩ 4 AgCl
(3)
arene ϭ p-cymene, X ϭ PF6 (6); arene ϭ benzene, X ϭ BF4 (7)
In both cases the two pairs of stereoisomers, fac (6a and
1
signed to a PN ligand with a chelating coordination mode 7a) and mer (6b and 7b), were formed. The H NMR spec-
while the lower-field signal belongs to a monodentate PN tra lack the characteristic signals of p-cymene or benzene.
ligand. The JP,P value (32.02 Hz) is indicative of a cis dis- The 31P{1H} NMR spectrum of 6 exhibits the AM6 pattern
2
Ϫ
position of the two atoms. Moreover, the FABϩ mass spec- of the PF6 counteranion. Furthermore, a singlet for the
trum shows a peak at m/z ϭ 669 due to the cation fac stereoisomer (chemical shift of chelate coordination)
[RuCl(PN)2]ϩ, which is the result of the loss of one chloride and the AMX pattern of a mer stereoisomer are observed
ion from 5. Two bands at 367 and 297 cmϪ1, assigned to for both derivatives. Two signals at high field due to the
the stretching vibration modes of the RuCl2 unit, were ob- mer form are typical of chelate coordination. However, the
served in the IR spectrum. It can be concluded from these resonance at δ ϭ 20.70 ppm could correspond to a chelat-
data that the complex is a monomeric, pentacoordinate ing or bridging PN ligand, which means that the compound
compound with one bidentate and one monodentate PN could be mono- or dinuclear in nature. In an effort to clar-
ligand in which the P atoms are in a cis disposition but can ify this point, high-resolution mass spectra were obtained
exchange their coordination modes at room temperature for 6 and 7. Only the spectrum of compound 6 will be dis-
through a fast process.
cussed as it is very similar to that of 7. The spectrum dis-
Interestingly, the reaction of [RuCl2(cod)(bpzm)] with 3 plays a group of signals corresponding to the fragment
equiv. of the ligand PN under reflux gave a precipitate that [{Ru(PN)3}{PF6}]ϩ, whose most intense peak appears at m/
was identified as complex 3, with no other compound being z ϭ 1045.2. In addition a signal at m/z ϭ 450.13 was ob-
detected. Complex 3 was present as four diastereoisomers: served, which is consistent with the dicationic fragment
the pair of enantiomers fac-3a and the pair mer-3b in a [{Ru(PN)3}]2ϩ, as deduced from the difference between the
molar ratio of 4:1. As stated previously, these isomers were lines in this group of half a unit. The overall fragmentation
also obtained when [RuCl2(PPh3)3] was used as the starting pattern for this molecule is indicated in Scheme 5. No evi-
material but always in a mixture with other derivatives (see dence for the existence of a dinuclear species was found in
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2547

B. R. Manzano et al.
FULL PAPER
the mass spectrum. Consequently, all the data indicate a
mononuclear structure for both derivatives (Scheme 6).
Figure 4. (a) ORTEP plot of the cation of the ∆ enantiomer of fac-
7a, showing the atom labelling; hydrogen atoms and phenyl groups
have been omitted for clarity, as have counterions and solvent mol-
ecules; (b) ball-and-stick plots for fac-7a, showing both enanti-
omers
Scheme 5. Fragmentation pattern for 6
angle decreases with κ2-PN coordination from 128.5(2)°[27]
in the free ligand to about 105° in 7a. Very similar angles
(about 103°) are present in the previously mentioned [Ru(-
pyphos)3] units. This situation can be seen as a consequence
of the inherent strain associated with the four-membered
chelate ring. Similarly, the RuϪN bonds are relatively
long[28] and the bite angles of the PN donor ligands are
small.
Scheme 6. Proposed structures for 6 and 7
Finally, it was possible to crystallise the fac isomer of 7
(i.e. 7a) as an acetone solvate and to determine its molecu-
lar structure by an X-ray diffraction study on a single crys-
tal. The corresponding ORTEP plot is shown in Figure 4,
selected bond lengths and angles are shown in Table 2 and
crystallographic data are given in the Exp. Sect. The com-
pound is mononuclear and exhibits a fac disposition of the
three phosphorus atoms. Only the structure for the ∆ iso-
mer is shown in Figure 4a, although it should be noted that
both the ∆ and Λ enantiomers are present in the same unit
cell (see Figure 4b).
At present, only one structure containing three four-
membered PN chelate rings has been deposited with the
CSD[26] and that corresponds to the complex [Ru-
(pyphos)3](µ-Na2)[Ru(pyphos)3] in which each pseudo-octa-
hedral ruthenium() centre has three PN chelating ligands
[pyphos ϭ 6-(diphenylphosphanyl)-2-pyridonate]. As in the
Hydride Complexes
We also tried to synthesise new hydride complexes con-
taining the PPh2MeIm ligand. In order to achieve this aim
we used two types of hydride starting material, one contain-
ing PPh3 and the other with more easily displaceable li-
gands — [RuHCl(PPh3)3] and [RuHCl(cod)(bpzm)].
When equivalent amounts of [RuHCl(PPh3)3] and
PPh2MeIm were mixed in toluene at 70 °C, mer-
[RuHCl(PPh3)2(κ2-P,N-PPh2MeIm)] (8) was isolated in
good yield [Equation (4)].
[RuHCl(PPh3)3] ϩ PN Ǟ
(4)
mer-[RuHCl(PPh3)2(κ2-PN)] (8) ϩ PPh3
1
The hydride region of the H NMR (C6D6) spectrum of
case of 7a, a fac disposition for the identical donor atoms 8 shows a quadruplet at δ ϭ Ϫ15.1 ppm (2JP,H ϭ 26.6,
2
was found.
2JP,H ϭ 23.5, JP,H ϭ 23.4 Hz) as the most characteristic
A comparison between the free and the chelate-coordi- signal. This relatively high-field chemical shift is typical for
nated ligand in fac-7a reflects the fact that the PϪCϪN a hydride ion trans to an N atom, as reported in the litera-
2548
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Eur. J. Inorg. Chem. 2004, 2542Ϫ2552

New (Polyphosphane)ruthenium Complexes
FULL PAPER
ture,[29] and is in contrast to the lower-field chemical shift
observed for hydride ions trans to Cl ligands.[11,30] The val-
ues of the three coupling constants, determined separately
Experimental Section
General Comments: All manipulations were carried out under Ar
using standard Schlenk techniques. Solvents (Merck) were dried
and distilled under N2 prior to use. [RuCl2(PPh3)3],[31]
1
by selective H{31P} NMR decoupling experiments, corre-
spond to a cis disposition of the hydride ion with respect
to the three P atoms, which also means a mer-PPP dispo-
sition. The 31P{1H} NMR (C6D6) spectrum of 8 confirms
the stereochemistry of the complex, since it consists of an
AMX pattern with one trans-PP coupling constant between
a PPh3 and a chelating PPh2MeIm group. Consequently,
the spectroscopic data indicate the presence of the mer ster-
eoisomer in solution (see Scheme 7). Obviously, complex 8
is isolated as a racemic mixture.
[RuHCl(PPh3)3],[32]
[RuCl2(bpzm)(cod)],[33]
[RuHCl(bpzm)-
(cod)],[33] [RuCl2(p-cymene)]2,[34] [RuCl2(C6H6)]2
and
[34]
PPh2MeIm[27] were prepared according to literature procedures.
NMR spectra were recorded at room temperature (ca. 22 °C), un-
less otherwise stated, with a Varian Unity Inova-400 (400 MHz for
1H; 161.9 MHz for 31P; 100.6 MHz for 13C) or with a Varian Unity-
300 (300 MHz for 1H; 121.4 MHz for 31P; 75.4 MHz for 13C) spec-
1
trometer. H NMR shifts are referenced to the residual proton of
the solvent as internal standard. All 31P shifts were referenced in-
ternally to H3PO4. The 31P,31P COSY spectrum was acquired using
a 30604 Hz spectral width; 24 transients were collected for each
240 increments. A 1 s relaxation delay, a 45° pulse width, and a
0.20 s acquisition time were used. IR spectra were recorded with a
Nicolet Impact 410 spectrophotometer as KBr pellets or with a
PerkinϪElmer 883 (4000Ϫ200 cmϪ1 range) as Nujol mulls. Con-
ductivity measurements were made at 25 °C with freshly prepared
10Ϫ3  solutions of the complex in acetone, using a CRISON 522
conductimeter. Molar conductivities (ΛM) are given in units of
Ω
Ϫ1·molϪ1·cm2. Elemental analyses were performed with a LECO
CHNS932 microanalyser. FABϩ mass spectra were recorded at the
University of Zaragoza with a VG AutoSpec or at the University
of Burgos with a Micromass Autospec by Liquid Secondary Ion
Mass Spectrometry (LSMISϩ) with Cs and NBA ions as the ma-
trix.
Scheme 7. Proposed structures of complexes 8 and 9
An excess of the ligand PPh2MeIm (6:1) was mixed with
[RuHCl(cod)(bpzm)] in THF at Ϫ80 °C and the hydrido
complex mer-[RuHCl(κ1-P-PPh2MeIm)2(κ2-P,N-PPh2MeIm)]
(9) was obtained [Equation (5)].
trans,mer-[RuCl2(PPh3)2(κ2-P,N-PPh2MeIm)]
(1):
PPh2MeIm
(29.5 mg, 0.11 mmol) was added to a suspension of [RuCl2(PPh3)3]
(106 mg, 0.11 mmol) in 20 mL of CH2Cl2 (1:1). The resulting mix-
ture was stirred and refluxed for 16 h. The original suspension be-
came a red solution, which was concentrated to dryness. The or-
ange solid obtained was washed with pentane (15 mL) and then
with diethyl ether (3 ϫ 15 mL) to remove any residual PPh3. Fi-
nally, it was dried under vacuum. Yield: 89% (94.8 mg). The prod-
uct is soluble in CHCl3, CH2Cl2 and acetone. It decomposes in
solution under air, giving rise to a green-brownish suspension after
some minutes. However, it can be stored, as a solid, under nitrogen
for months without appreciable decomposition. C52H45Cl2N2P3Ru
[RuHCl(cod)(bpzm)] ϩ 6 PN Ǟ
(5)
mer-[RuHCl(κ1-PN)2(κ2-PN)] (9) ϩ cod ϩ bpzm
1
The H (C6D6) and 31P{1H} NMR (C6D6) spectra of 9
are completely analogous to those of 8. Two of the phos-
phorus chemical shifts are typical of a monodentate coordi-
nation of the PN ligand while a resonance appearing at δ ϭ
Ϫ10 ppm indicates the existence of a chelating PPh2MeIm (962.85): calcd. C 64.87, H 4.71, N 2.91; found C 65.11, H 4.80, N
2.83. FABϩ: m/z ϭ 927 [M Ϫ Cl]ϩ, 665 [M Ϫ Cl Ϫ PPh3]ϩ, 403
group. Consequently, the presence of the mer stereoisomer,
as a racemic mixture, is again evident (see Scheme 7). The
two PPh3 ligands in compound 8 are monodentate
PPh3MeIm groups in 9.
[M Ϫ Cl Ϫ 2PPh3]ϩ.1H NMR (400 MHz, CDCl3, room temp.):
δ ϭ 7.9Ϫ6.7 (m, 40 H, 8 Ph), 6.6 (s, 1 H, H-Im), 5.56 (s, 1 H, H-
Im), 3.0 (s, 3 H, Me-Im) ppm.13C{1H} NMR (100.6 MHz, CDCl3,
room temp.): δ ϭ 150Ϫ125 (m, 49 C, 8 Ph, C2-Im), 130.7 (s, 1 C,
CH-Im), 123.4 (s, 1 C, CH-Im), 34.2 (s, 1 C, Me-Im) ppm. 31P{1H}
NMR: See Table 1. ΛM (25 °C, acetone) ϭ 10.35 ΩϪ1·molϪ1·cm2.
IR (nujol mull): ν˜ ϭ 326 cmϪ1 [ν(trans-RuCl2)].
Conclusion
Reaction of [RuCl2(PPh3)3] with PPh2MeIm in a 1:2 Molar Ratio:
The procedure is similar to that used for obtaining compound 1.
PPh2MeIm (59 mg, 0.22 mmol) was added to a suspension of
[RuCl2(PPh3)3] (106 mg, 0.11 mmol) (2:1) in 20 mL of CH2Cl2. The
resulting mixture was stirred and refluxed for 16 h. The original
suspension became a red solution, which was concentrated to dry-
ness. The orange solid obtained was washed with pentane (15 mL)
and then with diethyl ether (3 ϫ 10 mL) to remove any residual
PPh3 or PPh2MeIm. Finally, it was dried under vacuum. The re-
sulting mixture was studied by 31P{1H} NMR spectroscopy, and
the following compounds were detected (see Table 1 for the
31P{1H} NMR spectroscopic data): 1, fac-[RuCl(PPh3)(κ2-P,N-
We have prepared new families of (polyphosphane)Ru
complexes containing the ligand 2-(diphenylphosphanyl)-1-
methyl-1H-imidazole. In the complexes described, three
types of coordination modes for the N,P ligand have been
found: P-monodentate, chelate and brigde. An unexpected
rearrangement of [RuCl2(Pn)(PPh3)2] that leads, among
others, to the formation of dinuclear derivatives has been
found. The formation of these species involves an RuϪN
bond-breaking step that demonstrates the hemilabile behav-
iour of the ligand.
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2549

B. R. Manzano et al.
FULL PAPER
PPh2MeIm)2]Cl (2a) and mer-[RuCl(PPh3)(κ2-P,N-PPh2MeIm)2]Cl
(2b).
8.21. FABϩ: m/z ϭ 669 [M Ϫ Cl]ϩ, 403 [M Ϫ Cl Ϫ PN]ϩ. 1H
NMR (300 MHz, [D6]acetone, room temp.): δ ϭ 8.0Ϫ6.8 (m, 24
H, 4 Ph, 4 CH-Im), 2.97 (s, 3 H, Me-Im) 2.81 (s, 3 H, Me-Im)
ppm. 31P{1H} NMR: See Table 1. IR (Nujol mull): ν˜ ϭ 367, 297
cmϪ1 [ν(RuCl)].
Reaction of [RuCl2(PPh3)3] with PPh2MeIm in a 1:3 Molar Ratio:
The procedure is similar to that described for the 1:2 molar ratio.
Amounts are as follows: PPh2MeIm (88.6 mg, 0.33 mmol),
[RuCl2(PPh3)3] (106 mg, 0.11 mmol) and 20 mL of CH2Cl2. The [Ru(κ2-P,N-PPh2MeIm)3][PF6]2 (6): AgPF6 (253 mg, 1.00 mmol)
resulting mixture was studied by 31P{1H} NMR spectroscopy and
the following compounds were detected (see Table 1 for the
31P{1H} NMR spectroscopic data): 2a, 2b and fac-[RuCl(κ1-P-
PPh2MeIm)(κ2-P,N-PPh2MeIm)2]Cl (3a).
was added to a suspension of [RuCl2(p-cymene)]2 (153 mg,
0.25 mmol) in 8 mL of MeOH at room temperature (4:1). The mix-
ture was protected from light and stirred for 30 min. It was then
filtered and the precipitated AgCl was removed. PPh2MeIm
(266.1 mg, 1.00 mmol) was then added to the previous orange solu-
tion, and the resulting mixture was stirred at room temperature for
3 h. The solvent was removed under vacuum and the obtained oil
was transformed into a solid with pentane after stirring and
scratching. The yellow solid was filtered and dried under vacuum.
It is soluble in acetone. Yield: 87% relative to the ligand (344.7 mg).
When the reaction was performed with 1.50 mmol of the PN li-
gand, other products besides 6 were formed. The compound was
obtained as a mixture of four diastereoisomers: the pair of fac en-
antiomers 6a and the mer pair 6b. C48H45F12N6P5Ru (1189.9):
calcd. C 48.45, H 3.81, N 7.06; found C 48.14, H 3.93, N 7.32.
FABϩ (see also Scheme 5): m/z ϭ 1045 [M Ϫ PF6]ϩ, 450 [M Ϫ 2
Reaction of [RuCl2(PPh3)3] with PPh2MeIm in a 1:6 Molar Ratio:
The procedure is similar to that described for the 1:2 molar ratio.
Amounts are as follows: PPh2MeIm (177 mg, 0.66 mmol),
[RuCl2(PPh3)3] (106 mg, 0.11 mmol) and 30 mL of CH2Cl2. The
resulting mixture was studied by 31P{1H} NMR spectroscopy, and
the following compounds were detected (see Table 1 for the
31P{1H} NMR spectroscopic data): 2a, 2b, 3a and mer-[RuCl(κ1-
P-PPh2MeIm)(κ2-P,N-PPh2MeIm)2]Cl (3b).
[RuCl(κ1-P-PPh2MeIm)(κ2-P,N-PPh2MeIm)2]Cl (3): PPh2MeIm
(139.9 mg, 0.526 mmol) was added to
a
suspension of
[RuCl2(cod)(bpzm)] (75 mg, 0.175 mmol) in THF (30 mL) (3:1).
The resulting mixture was stirred and refluxed for 6 h. A yellow
solid was obtained which, after filtering and washing with n-pen-
tane (3 ϫ 10 mL), was dried under vacuum. Yield: 72% (123 mg).
The product is soluble in CH2Cl2 and CHCl3. C48H45Cl2N6P3Ru
(970.83): calcd. C 59.39, H 4.67, N 8.66; found C 59.22, H 4.81, N
8.57. FABϩ: m/z ϭ 935 [M]ϩ, 900 [M Ϫ Cl]ϩ, 634 [M Ϫ Cl Ϫ
PN]ϩ, 450 [M Ϫ ClϪ]2ϩ, 368 [M Ϫ Cl Ϫ 2 PN]ϩ, 267 [PN ϩ Hϩ]ϩ.
Ϫ
Ϫ
PF6 ]
Ϫ 2ϩ, 919 [M Ϫ PF6 Ϫ PF5]ϩ, 900 [M Ϫ PF6 Ϫ PF6]ϩ, 653
Ϫ
Ϫ
[M Ϫ PF6 Ϫ PF5 Ϫ PN]ϩ, 634 [M Ϫ PF6 Ϫ PF6 Ϫ PN]ϩ, 387
Ϫ
Ϫ
[M Ϫ PF6 Ϫ PF5 Ϫ 2 PN]ϩ, 368 [M Ϫ PF6 Ϫ PF6 Ϫ 2 PN]ϩ,
267 [PN ϩ Hϩ]ϩ.
6a: 1H NMR (400 MHz, [D6]acetone, room temp.): δ ϭ 8.2Ϫ6.6
(m, 36 H, 6 Ph, 6 CH-Im), 3.72 (s, 3 H, Me-Im) 3.63 (s, 3 H, Me-
Im) 3.57 (s, 3 H, Me-Im) ppm.
fac-[RuCl(κ1-P-PPh2MeIm)(κ2-P,N-PPh2MeIm)2]Cl (3a): 1H NMR
(400 MHz, CDCl3, room temp.): δ ϭ 9.0Ϫ6.2 (m, 36 H, 6 Ph, 3
CH-Im), 3.63 (s, 3 H, Me-Im), 3.22 (s, 3 H, Me-Im), 2.74 (s, 3 H,
Me-Im) ppm.
6b: 1H NMR (400 MHz, [D6]acetone, room temp.): δ ϭ 8.2Ϫ6.6
(m, 36 H, 6 Ph, 6 CH-Im), 3.61 (s, 9 H, Me-Im) ppm. 31P{1H}
NMR: See Table 1. IR (KBr): ν˜ ϭ 838 cmϪ1 [ν(PϪF), PF6Ϫ].
[Ru(κ2-P,N-PPh2MeIm)3][BF4]2 (7): AgBF4 (389.4 mg, 2.00 mmol)
mer-[RuCl(κ1-P-PPh2MeIm)(κ2-PN-PPh2MeIm)2]Cl
(3b):
1H
was added to
a suspension of [RuCl2(benzene)]2 (250 mg,
NMR (400 MHz, CDCl3, room temp.): δ ϭ 9.0Ϫ6.2 (m, 36 H, 6
Ph, 3 CH-Im), 3.79 (s, 3 H, Me-Im), 3.26 (s, 3 H, Me-Im), 2.68 (s,
3 H, Me-Im) ppm. 31P{1H} NMR: See Table 1.
0.5 mmol) in 15 mL of MeOH at room temperature (4:1). The mix-
ture was protected from light and stirred for 30 min. Then it was
filtered and the precipitated AgCl was removed. PPh2MeIm
(532.2 mg, 2.00 mmol) was added to the previous orange solution,
and the resulting mixture was stirred at room temperature for 3 h.
The solvent was removed under vacuum and the obtained oil was
transformed into a solid with pentane after stirring and scratching.
The yellow solid was filtered and dried under vacuum. It is soluble
in acetone. Yield: 76% relative to the ligand (535.8 mg). When the
reaction was performed with 3.00 mmol of the PN ligand, other
products besides 7 were formed. The compound was obtained as a
mixture of four diastereoisomers: the pair of fac enantiomers 7a
and the fac pair 7b. The mer enantiomers were crystallised from an
Et2O solution. C48H45B2F8N6P3Ru (1073.5): calcd. C 53.70, H
[(PPh3)(κ1-P-PPh2MeIm)ClRu(µ-Cl)2Ru(PPh3)(κ1-P-
PPh2MeIm)Cl] (4a): This compound was detected by 31P{1H}
NMR spectroscopy in a solution of 1 in CDCl3 after standing for
3 d at room temperature.
[(PPh3)ClRu(µ-Cl)2(µ2-P,N-PPh2MeIm)2Ru(PPh3)Cl] (4b): This
compound was obtained as a crystalline solid from a solution of 1
in CH2Cl2/hexane under nitrogen and it was also detected by
31P{1H} NMR spectroscopy in a solution of 1 in CDCl3 after
standing at room temperature for 3 d.
[(PPh3)(κ2-PN-PPh2MeIm)ClRu(µ-Cl)2Ru(PPh3)(κ2-PN-
PPh2MeIm)Cl] (4c): This compound was detected by 31P{1H}
NMR spectroscopy in a solution of 1 in CDCl3 after standing at
room temperature for 3 d.
4.23, N 7.83; found C 53.85, H 4.31, N 7.91. FABϩ: m/z ϭ 987 [M
Ϫ
Ϫ BF4Ϫ]ϩ, 450 [M Ϫ 2 BF4Ϫ 2ϩ, 919 [M Ϫ BF4 Ϫ BF3]ϩ), 900
]
Ϫ
Ϫ
[M Ϫ BF4 Ϫ BF4]ϩ, 653[M Ϫ BF4 Ϫ BF3 Ϫ PN]ϩ, 634 [M Ϫ
BF4 Ϫ BF4 Ϫ PN]ϩ, 387 [M Ϫ BF4 Ϫ BF3 Ϫ 2 PN]ϩ, 368 [M
Ϫ
Ϫ
Ϫ BF4 Ϫ BF4 Ϫ 2 PN]ϩ, 267 [PN ϩ Hϩ]ϩ. IR (KBr): ν˜ ϭ 1059
Ϫ
cis-P-[RuCl2(κ1-P-PPh2MeIm)(κ2-P,N-PPh2MeIm)] (5): PPh2-
cmϪ1 [ν(BϪF), BF4Ϫ], 544 [δ(FBF), BF4Ϫ].
MeIm (66 mg, 0.24 mmol) was added to
a suspension of
[RuCl2(cod)(bpzm)] (53.6 mg, 0.12 mmol) in 30 mL of THF (2:1).
The resulting mixture was stirred and refluxed for 14 h, then fil-
tered and the resulting solution concentrated to dryness. The pale-
green solid obtained was washed with diethyl ether (2 ϫ 10 mL)
and finally dried under vacuum. Yield: 68% (60 mg). The com-
pound is soluble in acetone and CHCl3. C32H30Cl2N4P2Ru
(704.55): calcd. C 54.55, H 4.29, N 7.95; found C 54.62, H 4.33, N
7a: 1H NMR (400 MHz, [D6]acetone, room temp.): δ ϭ 8.2Ϫ6.6
(m, 36 H, 6 Ph, 6 CH-Im), 3.72 (s, 3 H, Me-Im) 3.63 (s, 3 H, Me-
Im) 3.57 (s, 3 H, Me-Im) ppm.
7b: 1H NMR (400 MHz, [D6]acetone, room temp.): δ ϭ 8.2Ϫ6.6
(m, 36 H, 6 Ph, 6 CH-Im), 3.61 (s, 9 H, Me-Im) ppm. 31P{1H}
NMR: See Table 1.
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New (Polyphosphane)ruthenium Complexes
FULL PAPER
mer-[RuHCl(PPh3)2(κ2-P,N-PPh2MeIm)] (8): PPh2MeIm (20.4 mg,
X-ray Diffraction: Suitable crystals of complexes 4b·CH2Cl2 (red
block, dimensions 0.26 ϫ 0.23 ϫ 0.10 mm) and fac-7a·(CH3)2CO
0.077 mmol) was added to
a suspension of [RuHCl(PPh3)3]
(61.4 mg, 0.07 mmol) in 20 mL of toluene (1.1:1). The resulting (yellowish prism, dimensions 0.50 ϫ 0.30 ϫ 0.30 mm) were used
mixture was stirred and heated to 70 °C for 4 h. The original violet
suspension became a dark green solution and was concentrated to
dryness. The green solid obtained was washed with pentane
(15 mL) and dried under vacuum. Yield: 85% (55 mg). It is very
air-sensitive and soluble in toluene and benzene. C52H46ClN2P3Ru
(928.4): calcd. C 67.27, H 4.99, N 3.02; found C 67.21; H 5.02, N
for the structure determination. X-ray data (Table 3) were collected
using a Bruker SMART CCD area detector single-crystal dif-
fractometer with graphite-monochromated Mo-Kα radiation (λ ϭ
0.71073 A) by the -ω scan method at 173(2) K (4b) or 296(2) (fac-
7a). A total of 1271 frames of intensity data were collected for each
˚
compound. The first 50 frames were recollected at the end of data
3.14. 1H NMR (400 MHz, C6D6, room temp.): δ ϭ 8.2Ϫ6.6 (m, 41 collection to monitor for decay. The crystals used for the diffraction
H, 8 Ph, 1 CH-Im), 5.95 (s, 1 H, CH-Im), 3.5 (s, 3 H, Me-Im),
studies showed a small amount of decomposition during data col-
Ϫ15.1 (q, 2JP,H ϭ 26.6, 2JP,H ϭ 23.5, 2JP,H ϭ 23.4 Hz, 1 H, RuϪH) lection for 4b·CH2Cl2 (1.5%) and no decomposition for fac-
ppm. 31P{1H} NMR: See Table 1.
7a·(CH3)2CO. The integration process yielded a total of 22750 re-
flections for 4b·CH2Cl2 and 28912 for fac-7a·(CH3)2CO, of which
mer-[RuHCl(κ1-P-PPh2MeIm)2(κ2-P,N-PPh2MeIm)] (9): PPh2-
MeIm (351.6 mg, 1.32 mmol) was added to a suspension of
[RuHCl(cod)(bpzm)] (86.6 mg, 0.22 mmol) in 20 mL of THF at
Ϫ80 °C (6:1). The resulting mixture was stirred at this temperature
for 45 min and at room temperature for furthe 30 min. The original
suspension turned to a yellow solution with a small amount of
solid in suspension. This mixture was concentrated to dryness and
the yellow solid obtained was washed with diethyl ether (2 ϫ
10 mL) to remove any bpzm, cod and unreacted ligand, and finally
dried under vacuum. Yield: 73% (150 mg). The compound is very
air-sensitive and soluble in C6D6, but it is insoluble in acetone.
7606 [R(int) ϭ 0.0712] for 4b·CH2Cl2 and 11344 for fac-
7a·(CH3)2CO were independent. Absorption corrections were ap-
plied using the SADABS[35] program (maximum and minimum
transmission coefficients, 1.0000 and 0.809831 for 4b·CH2Cl2). The
structure was solved using the Bruker SHELXTL-PC[36] software
by direct methods and refined by full-matrix least-squares methods
on F2. Hydrogen atoms were included in calculated positions and
refined in the riding mode. For 4b·CH2Cl2 convergence was reached
at a final R1 ϭ 0.0377 [for I Ͼ 2σ(I)], wR2 ϭ 0.0789 (for all data),
437 parameters, with allowance for the thermal anisotropy of all
non-hydrogen atoms. The weighting scheme employed was w ϭ
C48H46ClN6P3Ru (936.39): calcd. C 61.57, H 4.95, N 8.97; found {σ2[Fo2 ϩ (0.0346P)2]}, with P ϭ (|Fo|2 ϩ 2|Fc|2)/3 and the goodness
C 61.63, H 4.93, N 8.99. FABϩ: m/z ϭ 935 [M Ϫ HϪ]ϩ, 900 [M Ϫ
HϪ Ϫ Cl]ϩ, 634 [M Ϫ HϪ Ϫ Cl Ϫ PN]ϩ, 450 [M Ϫ HϪ Ϫ ClϪ]2ϩ
of fit on F2 was 0.923 for all observed reflections. For fac-
7b·(CH3)2CO convergence was reached at a final R1 ϭ 0.0438 [for
I Ͼ 2σ(I)], wR2 ϭ 0.1221 (for all data), 668 parameters, with allow-
ance for the thermal anisotropy of all non-hydrogen atoms. The
,
368 [M Ϫ HϪ Ϫ Cl Ϫ 2 PN]ϩ, 267 [PN ϩ Hϩ]ϩ, 669 [M Ϫ HϪ
Ϫ
PN]ϩ, 403 [M Ϫ HϪ Ϫ 2 PN]ϩ.1H NMR (400 MHz, C6D6, room
temp.): δ ϭ 8.4Ϫ6.4 (m, 36 H, 6 Ph, 6 CH-Im), 3.45 (s, 3 H, Me-
weighting scheme employed was w ϭ [σ2(Fo)2 ϩ (0.0703P)2
ϩ
2
Im), 2.97 (s, 3 H, Me-Im), 2.81 (s, 3 H, Me-Im), Ϫ14.8 (q, JP,H
ഠ
(0.867P)], with P ϭ (|Fo|2 ϩ 2|Fc|2)/3 and the goodness of fit on F2
was 1.080 for all observed reflections. CCDC-223473 (4b·CH2Cl2)
25 Hz, 1 H, Ru-H) ppm. 31P{1H} NMR: See Table 1.
Table 3. Crystallographic data for 4b·CH2Cl2 and fac-7a·(CH3)2CO
4b·CH2Cl2
fac-7a·(CH3)2CO
Empirical formula
Formula mass
C36H34Cl6N2P2Ru
870.36
173(2)
C51H51B2F8N6OP3Ru
1131.58
296(2)
Temperature [K]
˚
Wavelength [A]
0.71073
0.71073
Crystal system
Space group
Unit cell dimensions
Monoclinic
P21/n
a ϭ 15.756(3) A
b ϭ 15.106(3) A
c ϭ 15.771(3) A
Triclinic
P1
a ϭ 12.296(3) A
b ϭ 13.030(2) A
¯
˚
˚
˚
˚
˚
˚
c ϭ 18.068(4) A
α ϭ 90°
α ϭ 78.252(15)°
β ϭ 101.554(3)°
β ϭ 88.132(18)°
γ ϭ 90°
3677.7(1)
γ ϭ 67.028(17)°
2605.9(10)
3
˚
Volume [A ]
Z
4
2
Density (calculated) [Mg/m3]
Absorption coefficient [mmϪ1
F(000)
1.572
0.979
1760
1.442
0.465
1156
]
Crystal size [mm]
Index ranges
0.26 ϫ 0.23 ϫ 0.10
Ϫ19 Յ h Յ 18, Ϫ18 Յ k Յ 15, Ϫ16 Յ l Յ 19
22750
7606 [R(int) ϭ 0.0712]
7606/0/437
0.50 ϫ 0.30 ϫ 0.30
Ϫ15 Յ h Յ 16, Ϫ17 Յ k Յ 17, Ϫ23 Յ l Յ 23
28912
11344 [R(int) ϭ 0.0300]
11344/0/668
1.080
R1 ϭ 0.0438, wR2 ϭ 0.1186
0.843/Ϫ0.455
Reflections collected
Independent reflections
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I Ͼ2σ(I)]
0.923
R1 ϭ 0.0377, wR2 ϭ 0.0715
0.561/Ϫ0.709
Ϫ3
˚
∆ρmax/min [e·A
]
Eur. J. Inorg. Chem. 2004, 2542Ϫ2552
www.eurjic.org
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2551

B. R. Manzano et al.
FULL PAPER
[16b]
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J. S. Kingsbury, J. P. A. Harrity, P. J. Bonitat-
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lographic data for this paper. These data can be obtained free of
charge at www.ccdc.cam.ac.uk/conts/retrieving.html [or from the
Cambridge Crystallographic Data Centre, 12 Union Road, Cam-
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Published Online April 7, 2004
2552
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Eur. J. Inorg. Chem. 2004, 2542Ϫ2552