Bis(pyrazol-1-yl)acetato ligands in ruthenium chemistry: Syntheses and structures of ruthenium(II) and ruthenium(III) complexes with bpza and bdmpza

Article abstract of DOI:10.1002/1099-0682(200203)2002:3<671::AID-EJIC671>3.0.CO;2-V

New ruthenium(II) and ruthenium(III) complexes with the ligands bis(pyrazol-1-yl) acetate (bpza) and bis(3,5-dimethylpyrazol-1-yl)acetate (bdmpza) are reported. The reaction of ruthenium trichloride hydrate, H[bpza], and excess PPh₃ yielded [Ru

Full text of DOI:10.1002/1099-0682(200203)2002:3<671::AID-EJIC671>3.0.CO;2-V

FULL PAPER
Bis(pyrazol-1-yl)acetato Ligands in Ruthenium Chemistry:
Syntheses and Structures of Ruthenium(II) and Ruthenium(III) Complexes with
bpza and bdmpza
[a]
[a]
[a]
[a]
´
´
Alberto Lopez-Hernandez, Rainer Müller, Henning Kopf, and Nicolai Burzlaff*
Keywords: Ruthenium / N ligands / Scorpionates / Tripodal ligands / Structural chemistry
New ruthenium(II) and ruthenium(III) complexes with the li-
ilar reaction conditions using the more bulky H[bdmpza]
gands bis(pyrazol-1-yl)acetate (bpza) and bis(3,5-dimethyl- yielded [Ru(bdmpza)Cl2(PPh3)]. Reaction of K[bpza] with
pyrazol-1-yl)acetate (bdmpza) are reported. The reaction of [RuCl2(PPh3)3] offered a second route to [Ru(bpza)Cl(PPh3)2].
ruthenium trichloride hydrate, H[bpza], and excess PPh3
yielded [Ru(bpza)Cl(PPh3)2] as a racemic mixture of an un-
Also, [Ru(bdmpza)Cl(PPh3)2] was accessed by this synthetic
approach. All three new complexes were characterized by X-
symmetrical isomer with traces of a symmetrical isomer. Sim- ray structure determination.
Introduction
The cyclopentadienylruthenium(II) complex [Ru(Cp)Cl-
(PPh3)2] has been used for more than 30 years as a versatile
starting material in thousands of reactions in organo-
metallics.[1Ϫ6] In the last ten years this chemistry has been
extended to [Ru(Cp*)Cl(PPh3)2][7Ϫ9] and, due to the firmly
established analogy between the cyclopentadienyl ligand
and the hydrotris(pyrazol-1-yl)borato ligand (Tp), also to
Figure 1. Metal complexes with Cp, Cp*, Tp, TpMe2, bpza, and
[Ru(Tp)Cl(PPh3)2].[10,11] It is thought that the differences in
the reactivity of these complexes are essentially determined
by the cone angle of triphenylphosphane (145°) as well as
the cone angles of the Cp (150°), Cp* (182°), and Tp (199°)
ligands.[10Ϫ14] Structural data of the complexes, confirming
bdmpza ligands
route to ruthenium(II) and ruthenium(III) complexes with
these new bis(pyrazol-1-yl)acetato ligands.
these steric effects, have been available for
a long
time.[4Ϫ6,8Ϫ10] Therefore, these bulky ligands are an import-
ant factor in the chemistry of these complexes by inducing
lability of one of the triphenylphosphane ligands.
Results and Discussion
First we investigated a one-step synthesis analogous to
the synthesis of [Ru(Cp)Cl(PPh3)2] reported by Bruce et
al.[3] Reaction of RuCl3ϫnH2O with bis(pyrazol-1-yl)acetic
acid (H[bpza]) and an excess of PPh3 in ethanol under re-
fluxing conditions yielded [Ru(bpza)Cl(PPh3)2] as the un-
symmetrical isomer 1b [Equation (1)].
Recently, bis(pyrazol-1-yl)acetato ligands, a new class of
scorpionate ligands with binding properties similar to those
of the cyclopentadienyl or the hydrotris(pyrazol-1-yl)borato
ligand (Figure 1), have been introduced to organometallic
and coordination chemistry.[15Ϫ20] The binding properties
as well as the steric hindrance of the two new ligands bis-
(pyrazol-1-yl)acetate (bpza) and bis(3,5-dimethylpyrazol-1-
yl)acetate (bdmpza) are between those of a Cp ligand and
a Cp* ligand.
Recently, we studied iron(II) complexes with these li-
gands Ϫ although with our main focus on bioinorganic
model complexes for iron enzymes.[17] Now we report on a
(1)
[a]
Fachbereich Chemie, Universität Konstanz, Fach M728,
78457 Konstanz, Germany
There are two possible isomeric products: (a) a symmet-
rical one (1a) with the chloride ion in trans position to the
Fax: (internat.) ϩ 49-(0)7531/88-3136
E-mail: nicolai@chemie.uni-konstanz.de
Eur. J. Inorg. Chem. 2002, 671Ϫ677
WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002 1434Ϫ1948/02/0303Ϫ0671 $ 17.50ϩ.50/0
671

´
´
A. Lopez-Hernandez, R. Müller, H. Kopf, N. Burzlaff
FULL PAPER
carboxylate group of the ligand and (b) an unsymmetrical
one (1b) with the carboxylate group trans to a PPh3 ligand.
The main isomer 1b obtained in this one-step synthesis is a
racemic mixture of two enantiomers. The 1H NMR spectra
of the crude reaction product showed only traces of the
symmetrical 1a. Pure product 1b could be obtained by col-
umn chromatography over silica followed by recrystalliza-
tion in methanol. The solubility of 1b in methanol is much
lower than that of 1a.
Table 2. Selected angles of the complexes 1b, 2, and 3
Angle [°]
1b
86.5(2)
82.1(2)
86.3(2)
87.79(14)
174.37(14)
81.58(15)
93.07(19)
90.57(18)
163.46(18)
95.07(18)
85.35(17)
170.51(17)
Ϫ
2
3
N(11)ϪRuϪN(21)
O(1)ϪRuϪN(11)
O(1)ϪRuϪN(21)
O(1)ϪRuϪCl(1)
O(1)ϪRuϪP(1)
O(1)ϪRuϪP(2)
N(11)ϪRuϪP(1)
N(21)ϪRuϪP(1)
N(11)ϪRuϪP(2)
84.05(9)
86.50(10)
87.73(10)
175.36(6)
85.45(8)
Ϫ
97.14(8)
172.99(6)
Ϫ
78.40(15)
88.23(14)
87.68(13)
170.52(9)
86.50(10)
91.36(9)
169.31(11)
92.08(11)
95.30(12)
173.65(11)
84.92(12)
84.58(11)
Ϫ
The coordination of the bpza ligand follows from the IR
signal in KBr matrix νasym(CO2Ϫ) ϭ 1653 cmϪ1. The obser-
vation of two doublets in the 31P NMR spectra [δ ϭ 43.8 N(21)ϪRuϪP(2)
Ϫ
(2JPP ϭ 31.0 Hz), 49.5 (2JPP ϭ 31.0 Hz)] and of two sets of
N(11)ϪRuϪCl(1)
89.62(9)
89.34(9)
90.90(6)
97.57(6)
Ϫ
N(21)ϪRuϪCl(1)
Cl(1)ϪRuϪCl(2)
Cl(1)ϪRuϪP(1)
Cl(1)ϪRuϪP(2)
Cl(2)ϪRuϪP(1)
P(1)ϪRuϪP(2)
1
signals for the pyrazolyl groups in the H and 13C NMR
spectra indicates an unsymmetrical coordination of the tri-
94.74(8)
91.36(10)
Ϫ
99.16(7)
95.79(6)
Ϫ
phenylphosphane ligands in 1b. Finally, the molecular
structure was proven by CHN analysis, mass spectra, and
an X-ray structure determination (Figure 2) of crystals of
1b obtained from a solution of 1b in ethanol layered with
diethyl ether. Selected bond lengths and angles are summar-
ized in Tables 1 and 2.
88.27(5)
Ϫ
103.36(10)
94.12(6)
˚
˚
2.360(3) A and N(21)ϪRu ϭ 2.100(6) A] are slightly shorter
˚
than those in a trans geometry [P(2)ϪRu ϭ 2.378(4) A and
˚
N(11)ϪRu ϭ 2.157(6) A]. This might be due to the trans
influence of the triphenylphosphane ligand and the pyrazo-
lyl group.
An analogous reaction of RuCl3 with excess PPh3 and
bis(3,5-dimethylpyrazol-1-yl)acetic acid (H[bdmpza]) yielded
[Ru(bdmpza)Cl2(PPh3)] (2) as an orange, air-sensitive com-
plex [Equation (2)].
(2)
Figure 2. Molecular structure of [Ru(bpza)Cl(PPh3)2] (1b); thermal
ellipsoids are shown at a 50% probability level; hydrogen atoms
and co-crystallised solvent are omitted for clarity
Complex 2 is paramagnetic, and therefore was only char-
acterized by mass spectrometry, CHN analysis, and infrared
spectroscopy (KBr matrix). The νasym(CO2Ϫ) at 1682 cmϪ1
established the coordination of bdmpza to the ruthenium
ion. An X-ray structural analysis of 2 finally confirmed a
constitution with the PPh3 ligand trans to one of the pyra-
zolyl groups (Figure 3). Selected bond lengths and bond
angles are summarised in Tables 1 and 2.
Table 1. Selected distances of the complexes 1b, 2, and 3
˚
Distance [A]
1b
2
3
RuϪN(11)
RuϪN(21)
RuϪO(1)
RuϪCl(1)
RuϪCl(2)
RuϪP(1)
2.157(6)
2.100(6)
2.181(6)
2.440(3)
Ϫ
2.360(3)
2.378(4)
1.241(9)
1.309(9)
1.566(10)
2.109(3)
2.184(3)
2.045(3)
2.346(2)
2.3581(19)
2.3715(18)
Ϫ
1.225(3)
1.298(3)
1.562(4)
2.199(4)
2.173(4)
2.133(3)
2.4157(17)
Ϫ
˚
Apart from the distances RuϪN(21) [2.184(3) A] and
2.3555(17)
˚
RuϪP(2)
2.3688(18) RuϪP(1) [2.3715(18) A], all other distances RuϪO, RuϪN,
O(2)ϪC(2)
O(1)ϪC(2)
C(1)ϪC(2)
1.241(5)
1.281(5)
1.539(6)
and RuϪCl are significantly shorter compared to those of
1b. This is caused by the ruthenium(III) centre in 2 instead
of ruthenium(II) in 1b. These two significantly longer dis-
tances again imply a trans influence between the PPh3 li-
gand and the pyrazolyl group of the bdmpza ligand.
The molecular structure shows one PPh3 ligand posi-
In a second attempt to obtain the target molecule
tioned trans to the carboxylate group of the bpza ligand [Ru(bdmpza)Cl(PPh3)2], potassium bis(3,5-dimethylpyr-
and the other phosphane ligand trans to a pyrazolyl group. azol-1-yl)acetate was allowed to react with [RuCl2(PPh3)3]
The distances of the bonds in the cis geometry [P(1)ϪRu ϭ [Equation (3)].
672
Eur. J. Inorg. Chem. 2002, 671Ϫ677

Bis(pyrazol-1-yl)acetato Ligands in Ruthenium Chemistry
FULL PAPER
Figure 3. Molecular structure of [Ru(bdmpza)Cl2(PPh3)] (2); ther-
mal ellipsoids are shown at a 50% probability level; hydrogen atoms
and co-crystallised solvent are omitted for clarity
Figure 4. Molecular structure of [Ru(bdmpza)Cl(PPh3)2] (3); ther-
mal ellipsoids are shown at a 50% probability level; hydrogen atoms
and co-crystallised solvent are omitted for clarity
a single-crystal X-ray structure analysis of 3 (Figure 4). Se-
lected bond lengths and bond angles of 3 are summarized
in Tables 1 and 2.
The IR spectrum of 3 shows bands at 1668 and 1570
cmϪ1 [νasym(CO2Ϫ) and ν(CϭN)]. For all three complexes
Ϫ
(3)
1a/1b, 2, and 3 we were not able to assign νsym(CO2
)
properly to one of the resonances in the region between
1400 and 1500 cmϪ1. This was due to the weakness of the
signals and several resonances of the PPh3 ligand in that re-
gion.
Complex 3 is rather sensitive to oxygen (especially com-
pared to the almost air-stable complexes 1a or 1b). This is
caused by the bigger steric hindrance of 3, causing a labili-
sation of the PPh3 ligands. This hindrance is indicated by a
much smaller angle N(11)ϪRuϪN(21) of 78.40(15)° com-
pared to 86.5(2)° in 1b. Another explanation might be, that
bdmpza is a better donor ligand compared to bpza due to
the four methyl groups in the pyrazolyl rings.
Also [Ru(bpza)Cl(PPh3)2] could be obtained in good
yield by reaction of potassium bis(pyrazol-1-yl)acetate with
[RuCl2(PPh3)3]. Both isomers 1a and 1b were formed
[Equation (4)].
In an analogous reaction with potassium hydrotris-
(pyrazol-1-yl)borate and [RuCl2(PPh3)3] the complex
[Ru(Tp)Cl(PPh3)2] was obtained by Hill et al.[10] Very re-
cently the complex [RuCl(PPh3)2(TPM)]Cl was synthesized
from tris(pyrazol-1-yl)methane (TPM) and [RuCl2(PPh3)3]
by Field and Messerle.[21] [Ru(bdmpza)Cl(PPh3)2] (3) was
obtained in good yield after simply washing with degassed
water and diethyl ether and was fully characterized. A
single signal in the 31P NMR spectrum as well as one set
of signals for the pyrazolyl groups in the 1H and 13C NMR
spectra indicate a symmetric geometry for 3. Proton signals
of 3 were assigned on the basis of cross-peaks observed in
a rotating frame Overhauser spectroscopy (ROESY) experi-
ment. The 13C NMR resonances of the methyl groups were
assigned by correlating them to the assigned proton reson-
ances using a heteronuclear multiple quantum coherence
(HMQC) experiment. The methyl group at position 3 of the
1
pyrazolyl groups (Me3) was found in the H NMR spectra
(4)
at δ ϭ 1.72 [13C NMR: δ ϭ 15.5], the methyl group at
position 5 (Me5) at δ ϭ 2.35 [13C NMR: δ ϭ 11.1]. A dis-
tinction of the quaternary pyrazolyl carbon resonances was
possible with a heteronuclear multiple bond correlation
(HMBC) experiment [13C NMR: δ ϭ 140.6 (C5), 157.3
Due to the simple workup and high yield, we now favour
(C3)]. The assignment of the NMR signals is in good agree- this second synthetic route to 1a/1b. Potassium chloride and
ment with those reported by Otero for similar niobium traces of excess base are removed by washing with degassed
complexes.[16] The symmetric structure was also proven by water. Thus, ruthenium complexes with bis(pyrazol-1-yl)-
Eur. J. Inorg. Chem. 2002, 671Ϫ677
673

´
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A. Lopez-Hernandez, R. Müller, H. Kopf, N. Burzlaff
FULL PAPER
acetato ligands are stable against hydrolysis, an imminent
advantage compared to hydrotris(pyrazolyl)borato ligands.
In contrast to unsymmetrical 1b, only a single 31P NMR
1
signal at δ ϭ 40.4 and one set of H NMR signals is found
for 1a. Both isomers of 1a/1b are rather stable and can be
stored under air as a solid. Assignment of the proton sig-
nals of 1a/1b was accomplished from the cross-peaks ob-
served in correlation spectroscopy (COSY) experiments and
ROESY experiments. HMQC experiments were used for
correlation of these assigned proton resonances with 13C
NMR resonances. In the NMR spectra of the symmetrical
isomer 1a only three proton resonances [δ ϭ 5.89 (H4), 6.87
(H3), 7.55 (H5)] and three carbon resonances [δ ϭ 107.6
(C4), 132.6 (C5), 146.6 (C3)] were detected for the pyrazolyl
groups. The pyrazolyl groups in 1b are no longer spectro-
scopically equivalent causing six 1H NMR signals [δ ϭ 5.20
(H3), 5.46 (H4), 5.97 (H4Ј), 7.44 (H3Ј), 7.79 (H5Ј), 7.79 (H5)]
and six 13C NMR signals [δ ϭ 106.5 (C4), 107.4 (C4Ј), 131.9
(C5 or C5Ј), 132.0 (C5 or C5Ј), 145.7 (C3Ј), 147.9 (C3)]. In
the ROESY experiment of 1b an NOE correlation was ob-
served between a signal at δ ϭ 7.84 (six ortho-H of the PPh3
ligand trans to the carboxylate donor group) and H3 indi-
cating a close spherical contact.
Scheme 1. Proposed mechanism for the conversion of 1b in 1a in
ethanol and of 1a in 1b in ethanol with excess PPh3
From the fact that the unsymmetrical isomer could be
isolated by recrystallization, it follows that it is stable
against conversion into 1a at ambient temperature for a
reasonable time. To investigate whether one of the isomers
is thermodynamically favoured, a mixture of the isomers
and PPh3 in ethanol was heated under reflux. After 4 h in
ethanol under refluxing conditions, surprisingly only traces
oxylate group might also interact with protons and there-
fore be a less efficient donor, causing this behaviour. In fu-
ture experiments we will concentrate on the question of
whether such interactions of the carboxylate donor and
protons, or even Lewis acids, could be used for changing
the reactivity of the complexes.
1
of 1b were detected by H NMR spectroscopy besides 1a.
Since this formation of the symmetrical isomer 1a seemed
to be incompatible with the one-step synthesis of 1b, a solu-
tion of 1a with traces of 1b and PPh3 in ethanol was heated
under reflux for 5 h. After this time 1b was the main prod-
uct and only traces of 1a were left. Obviously, the ratio 1a/
1b depends on whether excess PPh3 is present in the reac-
tion mixture or not. Very likely, this is due to the interme-
diate formation of a cationic solvent complex. For alcoholic
solutions of [Ru(Cp)Cl(PPh3)2] dissociation of a chloride
ligand and formation of a cationic alcohol complex is well
known.[1,3] The most likely position of the ethanol ligand is
the position trans to the carboxylate donor group. Ex-
change of the ethanol ligand by a chloride ion will therefore
result in the symmetrical isomer 1a (Scheme 1). With excess
PPh3 an intermediate cationic complex [Ru(bpza)(PPh3)3]Cl
might be formed. Similar complexes [Ru(Cp)(dppm)-
Conclusions
A simple synthetic route to the ruthenium(II) complexes
[Ru(bpza)Cl(PPh3)2] (1a/1b) and [Ru(bdmpza)Cl(PPh3)2]
(3) was established by reaction of the potassium bis(pyra-
zol-1-yl)acetates with [RuCl2(PPh3)3]. Complex 3 seemed to
be more active towards exchange of a PPh3 ligand by an-
other donor, whereas in 1a/1b the ratio of the symmetrical
isomer 1a to the unsymmetrical isomer 1b could be influ-
enced by adding PPh3 during heating under reflux. Thus,
both complexes are promising starting complexes for future
organometallic experiments.
Experimental Section
(PPh3)]PF6 and [Ru(Cp*)(PHPh2)3]Cl were recently re- All experiments were carried out in Schlenk tubes under argon.
ported.[22,23] Both PPh3 ligands trans to pyrazolyl groups
are more labile than the one trans to the carboxylate donor
group because of the trans influence of the pyrazolyl
The solvents were dried by standard procedures, distilled, and
stored under argon. Microcrystalline precipitates were separated by
filtration or centrifugation with a Hettich Rotina 46 R Schlenk
tube centrifuge. IR: Biorad FTS 60, CaF2 cuvettes (0.5 mm) or
groups. Therefore, in this case substitution for a chloride
KBr matrix. 1H NMR and 13C NMR: Bruker WM 250, Bruker
ion will result in formation of the unsymmetrical isomer
1b (Scheme 1).
Finally, we observed that traces of alcohols or THF in
NMR samples caused significant changes in the NMR
AC 250, δ values relative to TMS. 31P NMR: JEOL GX 400. Two-
dimensional NMR experiments: Bruker DRX 600 (Avance). EI-
MS and FAB-MS: modified Finnigan MAT 312. Elemental ana-
lyses: Analytical Laboratory of the Fachbereich Chemie. A modi-
fied Siemens P4 diffractometer was used for X-ray structure deter-
spectra again indicating an interaction between 1a/1b and
traces of these donor solvents. In protic solvents the carb- minations. Bis(pyrazol-1-yl)acetic acid and bis(3,5-dimethylpyra-
674 Eur. J. Inorg. Chem. 2002, 671Ϫ677

Bis(pyrazol-1-yl)acetato Ligands in Ruthenium Chemistry
FULL PAPER
zol-1-yl)acetic acid were synthesised from pyrazole and 3,5-di- acetic acid (376 mg, 1.51 mmol) and PPh3 (1.20 g, 4.57 mmol)
methylpyrazole as reported recently.[17,18] [RuCl2(PPh3)3] was in EtOH (30 mL). The mixture was heated under reflux for 1 h,
prepared according to the literature.[24] Hydrated ruthenium tri-
chloride (35Ϫ40% Ru) was used as purchased from Merck.
cooled in an ice bath and the precipitate was collected by filtration.
The brownish residue was washed with CH2Cl2 (30 mL) and the
now orange residue was dried in vacuo. Crystals suitable for a X-
ray structure determination were obtained from a solution of 2
in acetonitrile and also from a solution in CHCl3. Yield 660 mg
(0.97 mmol, 64%), m.p. 260Ϫ265 °C (dec.). FAB MS (NBOH
matrix): m/z (%) ϭ 722 (4) [Mϩ ϩ CH3CN], 681 (4) [Mϩ], 646 (18)
[(M Ϫ Cl)ϩ], 611 (6) [(M Ϫ Cl2)ϩ], 566 (6) [(M Ϫ Cl2 Ϫ CO2)ϩ].
Synthesis of [Ru(bpza)Cl(PPh3)2] (1a/1b). ؊ Method A: A solution
of RuCl3 ϫ n H2O (670 mg, 2.65 mmol) and bis(pyrazol-1-yl)acetic
acid (578 mg, 3.00 mmol) in EtOH (40 mL) was added over a
period of 10 min to
a refluxing solution of PPh3 (2.09 g,
7.95 mmol) in EtOH (80 mL). The mixture was maintained under
reflux for 3 h, cooled to ambient temperature and the solvent was
evaporated. The crude product was loaded with CH2Cl2 on a short
column of silica (length 6 cm, i.d. 4 cm). The column was washed
with CH2Cl2 (150 mL). Finally, the pure product was recovered
with MeOH. The dark yellow MeOH solution was concentrated in
IR (KBr): ν ϭ 1682 s (CO2Ϫ), 1560 w (CϭN), 1482 w, 1458 w, 1436
˜
w cmϪ1. C30H30Cl2N4O2PRuϫCH3CN (722.60): calcd. C 53.19, H
4.60, N 9.69; found C 53.32, H 4.23, N 9.83.
Synthesis of [Ru(bdmpza)Cl(PPh3)2] (3): Reaction of bis(3,5-di-
vacuo to 20 mL. The precipitated yellow product was filtered off methylpyrazol-1-yl)acetic acid (248 mg, 1.00 mmol) in THF
and dried in vacuo. It was dissolved in CH2Cl2, precipitated with
n-pentane, filtered off, and dried in vacuo. The unsymmetrical iso-
(25 mL) with potassium tert-butoxide (112 mg, 1.00 mmol) and
[RuCl2(PPh3)3] (953 mg, 0.99 mmol) according to Method
B
mer 1b was obtained as a yellow crystal powder. Suitable crystals yielded 3 as an orange crystal powder. Suitable crystals of 3 for X-
of 1b for X-ray structure analysis were obtained from a solution in ray structure analysis were obtained from a solution in CHCl3.
EtOH layered with diethyl ether. Yield 1.23 g (1.44 mmol, 54%), Yield 815 mg (0.90 mmol, 91%), m.p. 201Ϫ205 °C (dec.). 1H NMR
m.p. 194Ϫ196 °C. Ϫ Method B: To a solution of bis(pyrazol-1-
(CDCl3, 250 MHz): δ ϭ 1.72 (s, 3 H, Me3), 2.35 (s, 3 H, Me5), 5.42
yl)acetic acid (200 mg, 1.04 mmol) in THF (25 mL) potassium tert- (s, 2 H, H4), 6.45 (s, 1 H, CH), 6.90 (m, 12 H, PPh3), 7.04 (m, 6
butoxide (117 mg, 1.04 mmol) was added and the mixture stirred H, PPh3), 7.31 (m, 12 H, PPh3). 13C NMR (CDCl3, 62.9 MHz):
for 1 h at ambient temperature. A white precipitate formed during δ ϭ 11.1 (Me5), 15.5 (Me3), 69.1 (CH), 109.3 (C4), 126.5 (vt, JC,P ϭ
this time indicated the formation of the potassium carboxylate.
[RuCl2(PPh3)3] (1.00 g, 1.04 mmol) was added and the mixture was
4.2 Hz, m-PPh3), 128.0 (p-PPh3), 134.5 (vt, JC,P ϭ 4.2 Hz, o-PPh3),
136.2 (d, JC,P ϭ 39.1 Hz, i-PPh3), 140.6 (C5), 157.3 (C3), 168.2
stirred at ambient temperature for 30 min, during which time the (CO2Ϫ). 31P NMR (CDCl3, 161.8 MHz): δ ϭ 35.3. FAB-MS
colour of the brown suspension changed to orange. The solvent
was removed in vacuo and the residue was washed with degassed
water (2 ϫ 20 mL) and diethyl ether (2 ϫ 20 mL) and dried in
vacuo to yield a mixture of 1a/1b as an orange crystal powder.
(NBOH-matrix): m/z (%) ϭ 908 (0.5) [Mϩ], 873 (1) [(M Ϫ Cl)ϩ],
648 (3) [MHϩ Ϫ PPh3], 611 (2) [(MH Ϫ PPh3 Ϫ Cl)ϩ]. IR (THF):
ν ϭ 1672 s (CO2Ϫ), 1571 w (CϭN) cmϪ1. IR (CH2Cl2): ν ϭ 1662
˜
˜
s (CO2Ϫ), 1571 w (CϭN) cmϪ1. IR (KBr): ν ϭ 1668 s (CO2Ϫ), 1570
˜
Yield 760 mg (0.89 mmol, 86%), m.p. 188Ϫ192 °C. FAB-MS w (CϭN), 1482 w, 1458 w, 1432 m cmϪ1. C48H45ClN4O2P2-
(NBOH matrix): m/z (%) ϭ 853 (2) [MHϩ], 817 (4) [(MH Ϫ Cl)ϩ], Ruϫ3CHCl3 (1266.52): calcd. C 48.37, H 3.82, N 4.42; found C
590 (11) [MHϩ Ϫ PPh3], 555 (5) [(MH Ϫ PPh3 Ϫ Cl)ϩ]. 48.50, H 3.98, N 4.21.
C44H37ClN4O2P2RuϫH2OϫEtOH (916.36): calcd. C 60.29, H 4.95,
1
N 6.11; found C 60.58, H 4.73, N 6.00. Ϫ 1a: H NMR (CDCl3,
X-ray Structure Determinations: Single crystals of 1b, 2, and 3 were
sealed in glass capillaries at room temperature. A modified Siemens
3
250 MHz): δ ϭ 5.89 (vt, JH,H ϭ 2.3 Hz, 2 H, H4), 6.61 (s, 1 H,
3
CH), 6.87 (d, JH,H ϭ 1.9 Hz, 2 H, H3), 7.04 (m, 12 H, m-PPh3),
P4-diffractometer was used for data collection (Wyckhoff tech-
3
7.21 (m, 6 H, p-PPh3), 7.43(m, 12 H, o-PPh3), 7.55 (d, JH,H
ϭ
˚
nique, graphite monochromator, Mo-Kα radiation, λ ϭ 0.71073 A,
2.5 Hz, 2 H, H5). 13C NMR (CDCl3, 62.9 MHz): δ ϭ 75.5 (CH),
107.6 (C4), 127.1 (vt, JC,P ϭ 3.7 Hz, m-PPh3), 128.8 (p-PPh3), 132.6
(C5), 134.9 (vt, JC,P ϭ 4.5 Hz, o-PPh3), 135.0 (d, JC,P ϭ 40.1 Hz, i-
PPh3), 146.6 (C3), 166.1 (CO2Ϫ). 31P NMR (CDCl3, 161.8 MHz):
scan rate 4Ϫ30 °minϪ1 in ω). The structures were solved and re-
fined using the SHELX-97 program package (refined with full-mat-
rix least squares against F2).[25] A weighting scheme was applied in
the last steps of the refinement with w ϭ 1/[σ2(F2o) ϩ (aP)2 ϩ bP]
and P ϭ [2F2c ϩ max(F2o,0)]/3. Hydrogen atoms were included in
their calculated positions and refined in a ‘‘riding model’’. One
molecule of ethanol and water co-crystallised per asymmetric unit
in 1b, one molecule of CHCl3 in 2, and three molecules of CHCl3
in 3. The co-crystallised water in the structure of 1b can be ex-
plained as being due to the crystallisation of 1b in an open flask.
Crystals of 2 were also obtained from a solution in acetonitrile.
The X-ray structure determination of these crystals resulted in an
almost identical structure model but with higher R factors.
Therefore, this structure 2ϫCH3CN is not discussed here although
the data were deposited with CCDC (see below). Two of the
CHCl3 molecules in the structure of 3 are severely disordered caus-
ing relatively high R factors. All details and parameters of the
measurements are summarised in Table 3. Crystallographic data
(excluding structure factors) for the structures reported in this
paper have been deposited with the Cambridge Crystallographic
δ ϭ 40.4. IR (THF): ν˜ ϭ 1670 s (CO2Ϫ), 1653 m, 1507 w cmϪ1
.
IR (KBr): ν ϭ 1653 s (CO2Ϫ), 1482 w, 1433 m, 1408 w cmϪ1. Ϫ
˜
1
1b: H NMR (CDCl3, 250 MHz): δ ϭ 5.20 (s, 1 H, H3), 5.46 (s, 1
H, H4), 5.97 (s, 1 H, H4Ј), 6.84 (s br, 6 H, o-PPh3), 7.07 (m, 16 H,
CH and p-PPh3 and m-PPh3), 7.26 (m, 3 H, p-PPh3), 7.44 (s, 1 H,
H3Ј), 7.84(m, 8 H, o-PPh3 and H5 and H5Ј). 13C NMR (CDCl3,
62.9 MHz): δ ϭ 74.2 (CH), 106.5 (C4), 107.4 (C4Ј), 127.3 (d, JC,P ϭ
9.1 Hz, m-PPh3), 127.6 (d, JC,P ϭ 9.0 Hz, m-PPh3), 128.7 (p-PPh3),
129.2 (p-PPh3), 131.9 (C5 or C5Ј), 132.0 (C5 or C5Ј), 133.9 (d, JC,P ϭ
9.0 Hz, o-PPh3), 134.4 (d, JC,P ϭ 9.4 Hz, o-PPh3), 134.5 (d, JC,P
ϭ
40.4 Hz, i-PPh3), 135.3 (d, JC,P ϭ 40.5 Hz, i-PPh3), 145.7 (C3Ј),
147.9 (C3), 166.6 (CO2Ϫ). 31P NMR (CDCl3, 161.8 MHz): δ ϭ 43.8
(2JPP ϭ 31.0 Hz), 49.5 (2JPP ϭ 31.0 Hz). IR (CH2Cl2): ν˜ ϭ 1661 s
(CO2Ϫ), 1481 w cmϪ1. IR (KBr): ν ϭ 1653 s (CO2Ϫ), 1482 w, 1433
˜
m cmϪ1
.
Synthesis of [Ru(bdmpza)Cl2(PPh3)] (2): A solution of RuCl3 ϫ n Data Centre as supplementary publication no. CCDC-168912
H2O (383 mg, 1.52 mmol) in EtOH (20 mL) was added over a (1bϫH2OϫEtOH), -168913 (2ϫCHCl3), -168914 (2ϫCH3CN)
period of 10 min to a solution of bis(3,5-dimethylpyrazol-1-yl)- and -168915 (3ϫ3CHCl3). Copies of the data can be obtained free
Eur. J. Inorg. Chem. 2002, 671Ϫ677
675

´
´
A. Lopez-Hernandez, R. Müller, H. Kopf, N. Burzlaff
FULL PAPER
Table 3. Structure determination details of compounds 1b, 2, and 3
1b
2
3
Empirical formula
Formula mass
C44H37ClN4O2P2RuϫH2OϫH5C2OH C30H30Cl2N4O2PRuϫCHCl3 C48H45ClN4O2P2Ruϫ3CHCl3
916.32
800.89
1266.44
orange prism
monoclinic
P21/c
Crystal colour/habit
Crystal system
Space group
yellow cube
monoclinic
P21/n
orange cube
triclinic
¯
P1
˚
a [A]
9.969(10)
19.37(3)
22.96(3)
90
96.64(8)
90
4405(10)
2.07Ϫ25.01
Ϫ11 to 11
Ϫ9 to 23
Ϫ27 to 27
1888
10.113(7)
11.908(9)
15.583(10)
91.48(7)
108.59(3)
103.07(6)
1723(2)
2.13Ϫ27.00
Ϫ6 to 12
Ϫ15 to 14
Ϫ19 to 18
810
14.057(6)
31.792(19)
14.421(10)
90
115.72(5)
90
5806(6)
2.02Ϫ27.01
Ϫ17 to 0
Ϫ40 to 0
Ϫ16 to 18
2568
˚
b [A]
˚
c [A]
α [°]
β [°]
γ [°]
3
˚
V [A ]
θ [°]
h
k
l
F(000)
Z
4
2
4
µ(Mo-Kα) [mmϪ1
]
0.536
0.924
0.827
Crystal size [mm]
0.4 ϫ 0.2 ϫ 0.2
1.382
239(2)
0.4 ϫ 0.35 ϫ 0.35
1.544
232(2)
0.6 ϫ 0.4 ϫ 0.4
1.449
242(2)
Dc [gcmϪ3
T [K]
]
Reflections collected
Independent reflections
10245
7653
8278
7482
13162
12654
Observed reflections [Ͼ 2σ(I)] 3899
6311
397
9115
703
Parameter
530
Restraints
2
0
132
0.0950
10.8122
0.0635
0.0944
0.1660
0.1908
1.503/Ϫ1.121
Wt. parameter a
Wt. parameter b
R1 (obsd.)
R2 (overall)
wR1 (obsd.)
wR2 (overall)
0.0769
2.4297
0.0586
0.1447
0.1328
0.1872
0.900/Ϫ1.022
0.0437
1.1694
0.0354
0.0462
0.0873
0.0934
0.757/Ϫ0.756
3
˚
Diff. peak/hole [e/A ]
[6]
[7]
[8]
M. I. Bruce, H. Hinterding, E. R. T. Tiekink, Z. Kristallogr.
1993, 205, 287Ϫ290.
M. S. Chinn, D. M. Heinekey, J. Am. Chem. Soc. 1990, 112,
5166Ϫ5175.
D. C. Smith Jr., C. M. Haar, L. Luo, C. Li, M. E. Cucullu, C.
H. Mahler, S. P. Nolan, W. J. Marshall, N. L. Jones, P. J. Fagan,
Organometallics 1999, 18, 2357Ϫ2361.
of charge on application to CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK [Fax: (internat.) 44-1223/336-033; E-mail:
ϩ
deposit@ccdc.cam.ac.uk]. Structure figures were prepared with the
program Diamond 2.1c.[26]
[9]
Acknowledgments
´
´
I. A. Guzei, M. A. Paz-Sandoval, R. Torres-Lubian, P. Juarez-
Saavedra, Acta Crystallogr., Sect. C 1999, 55, 1090Ϫ1092.
N. W. Alcock, I. D. Burns, K. S. Claire, A. F. Hill, Inorg. Chem.
1992, 31, 2906Ϫ2908.
N. B. thanks the Fonds der Chemie for a Liebig-Stipendium and
Prof. Dr. H. Fischer for support and discussion. We are indebted
to Mr. Hägele for recording mass spectra, Mr. Haunz for recording
31P NMR spectra and Ms. Friemel for two-dimensional NMR ex-
periments.
[10]
[11]
[12]
B. Buriez, I. D. Burns, A. F. Hill, A. J. P. White, D. J. Williams,
J. D. E. T. Wilton-Ely, Organometallics 1999, 18, 1504Ϫ1516.
L. E. Manzer, C. A. Tolman, J. Am. Chem. Soc. 1975, 97,
1955Ϫ1956.
C. A. Tolman, Chem. Rev. 1977, 77, 313Ϫ348.
N. Kitajima, W. B. Tolman, Prog. Inorg. Chem. 1995, 43,
419Ϫ531.
[13]
[14]
[1]
Review: S. G. Davies, J. P. McNally, A. J. Smallridge, Adv. Or-
ganomet. Chem. 1990, 30, 1Ϫ76.
T. Blackmore, M. I. Bruce, F. G. A. Stone, J. Chem. Soc. A
[15]
[2]
´
˜
A. Otero, J. Fernandez-Baeza, J. Tejeda, A. Antinolo, F. Car-
´
´
´
rillo-Hermosilla, E. Dıez-Barra, A. Lara-Sanchez, M. Fernan-
dez-Lopez, M. Lanfranchi, M. A. Pellinghelli, J. Chem. Soc.,
1971, 2376Ϫ2382.
M. I. Bruce, C. Hameister, A. G. Swincer, R. C. Wallis, Inorg.
[3]
´
Dalton Trans. 1999, 3537Ϫ3539.
´
˜
A. Otero, J. Fernandez-Baeza, J. Tejeda, A. Antinolo, F. Car-
Synth. 1982, 21, 78Ϫ84.
M. I. Bruce, F. S. Wong, B. W. Skelton, A. H. White, J. Chem.
[4]
[16]
´
´
´
Soc., Dalton Trans. 1981, 1398Ϫ1405.
E. R. T. Tiekink, Z. Kristallogr. 1992, 198, 158Ϫ161.
rillo-Hermosilla, E. Dıez-Barra, A. Lara-Sanchez, M. Fernan-
[5]
´
dez-Lopez, J. Chem. Soc., Dalton Trans. 2000, 2367Ϫ2374.
676
Eur. J. Inorg. Chem. 2002, 671Ϫ677

Bis(pyrazol-1-yl)acetato Ligands in Ruthenium Chemistry
FULL PAPER
J. Bezler, Dissertation, University of Würzburg, Germany,
1995.
P. S. Hallman, T. A. Stephenson, G. Wilkinson, Inorg. Synth.
1970, 12, 237Ϫ240.
[17]
[23]
[24]
[25]
[26]
A. Beck, B. Weibert, N. Burzlaff, Eur. J. Inorg. Chem. 2001,
521Ϫ527.
[18]
N. Burzlaff, I. Hegelmann, B. Weibert, J. Organomet. Chem.
2001, 626, 16Ϫ23.
[19]
´
˜
A. Otero, J. Fernandez-Baeza, A. Antinolo, F. Carrillo-Hermo-
G. M. Sheldrick, SHELX-97, Programs for Crystal Structure
Analysis, University of Göttingen, Germany, 1997.
K. Brandenburg, M. Berndt, Diamond Ϫ Visual Crystal Struc-
ture Information System, Crystal Impact GbR, Bonn, Ger-
many, 1999; for software review see: W. T. Pennington, J. Appl.
Crystallogr. 1999, 32, 1028Ϫ1029.
´
´
silla, J. Tejeda, E. Dıez-Barra, A. Lara-Sanchez, L. Sanchez-
´
Barba, I. Lopez-Solera, M. R. Ribeiro, J. M. Campos, Organo-
metallics 2001, 20, 2428Ϫ2430.
[20]
[21]
N. Burzlaff, I. Hegelmann, Inorg. Chim. Acta, submitted.
L. D. Field, B. A. Messerle, L. Soler, I. E. Buys, T. W. Hambley,
J. Chem. Soc., Dalton Trans. 2001, 1959Ϫ1965.
Received August 24, 2001
[22]
´
R. Torres-Lubian, M. J. Rosales-Hoz, A. M. Arif, R. D. Ernst,
[I01330]
M. A. Paz-Sandoval, J. Organomet. Chem. 1999, 585, 68Ϫ82.
Eur. J. Inorg. Chem. 2002, 671Ϫ677
677