Preparation of pyrazole-pyrazolate half-sandwich complexes of ruthenium and osmium

Article abstract of DOI:10.1002/ejic.201000799

Pyrazole (HRpz) [MCl(η⁶-p-cymene)(HRpz)L]BPh₄ (1-8) and imidazole (HIm) complexes [MCl(η⁶-p-cymene)(HIm)L] BPh₄ (9-10) [M = Ru, Os; R = H, 3-Me, 3,5-Me₂; L = P(OEt)₃, PPh(OEt)₂, PPh₂OEt, CNtBu] were prepared by allowing the dichloro compounds MCl₂(η⁶-p- cymene)L to react with the appropriate azole in the presence of NaBPh ₄. Treatment of the dichloro complexes with an excess of both pyrazole and NEt₃ yielded the pyrazole-pyrazolate derivatives [M(Rpz)(η⁶-p-cymene)(HRpz)L]BPh₄ (11-14). Conversely, the reaction of carbonyl compounds RuCl₂(η⁶-p-cymene) (CO) with pyrazole or imidazole yielded the bisazole complexes [MCl(η⁶-p-cymene)(HRpz)₂]BPh₄ or [MCl(η⁶-p-cymene)(HIm)₂]BPh₄ (15-17). The complexes were characterised spectroscopically (IR and ¹H, ¹³C, ³¹P NMR) and by X-ray crystal structure analysis [RuCl(η⁶-p-cymene)(HRpz){PPh(OEt)₂}]BPh₄ (1b), [Ru(pz)(η⁶-p-cymene)(HRpz){P(OEt)₃}]BPh ₄ (11a) and [RuCl(η⁶-p-cymene)(HRpz) ₂]BPh₄ (15).

Full text of DOI:10.1002/ejic.201000799

FULL PAPER
DOI: 10.1002/ejic.201000799
Preparation of Pyrazole–Pyrazolate Half-Sandwich Complexes of Ruthenium
and Osmium
Gabriele Albertin,*[a] Stefano Antoniutti,[a] Jesús Castro,[b] and Soledad García-Fontán[b]
Keywords: Ruthenium / Osmium / Sandwich complexes / Half-sandwich complexes / N ligands / Nitrogen heterocycles
Pyrazole (HRpz) [MCl(η6-p-cymene)(HRpz)L]BPh4 (1–8) and
imidazole (HIm) complexes [MCl(η6-p-cymene)(HIm)L]BPh4
(9–10) [M = Ru, Os; R = H, 3-Me, 3,5-Me2; L = P(OEt)3,
PPh(OEt)2, PPh2OEt, CNtBu] were prepared by allowing the
dichloro compounds MCl2(η6-p-cymene)L to react with the
appropriate azole in the presence of NaBPh4. Treatment of
the dichloro complexes with an excess of both pyrazole and
NEt3 yielded the pyrazole–pyrazolate derivatives [M(Rpz)(η6-
p-cymene)(HRpz)L]BPh4 (11–14). Conversely, the reaction of
carbonyl compounds RuCl2(η6-p-cymene)(CO) with pyrazole
or imidazole yielded the bisazole complexes [MCl(η6-p-
cymene)(HRpz)2]BPh4 or [MCl(η6-p-cymene)(HIm)2]BPh4
(15–17). The complexes were characterised spectroscopically
(IR and 1H, 13C, 31P NMR) and by X-ray crystal structure
analysis [RuCl(η6-p-cymene)(HRpz){PPh(OEt)2}]BPh4 (1b),
[Ru(pz)(η6-p-cymene)(HRpz){P(OEt)3}]BPh4 (11a) and [RuCl-
(η6-p-cymene)(HRpz)2]BPh4 (15).
(η6-p-cymene)P]BPh4, cyanoguanidine [M(η6-p-cymene)-
{NCN(H)C(NH2)NH}P]+ and imine complexes [M(η6-p-
cymene){HN=C(H)Ar}P]+ of ruthenium and osmium sta-
bilised by the half-sandwich fragment M(η6-p-cymene)P (P
= phosphite ligands).[11]
We have now extended these studies to include HRpz
and HIm ligands, and here we report the synthesis and
characterisation of some azole and of the first pyrazole–
pyrazolate half-sandwich complexes of the iron triad.
Introduction
The chemistry of transition metal complexes containing
pyrazole (HRpz), pyrazolate (pz) and imidazole (HIm) as
ligands has been extensively developed in the past few years
and a number of complexes have been reported.[1–5] Interest
in these studies stems from the potential of HRpz as a li-
gand, which may act as monodentate ligand, through its
pyridinic nitrogen atom, or as either a monodentate or a
bidentate bridging ligand, in a pz anion.[1–5] In addition,
the possibility of using substituents on the heterocyclic ring
may modify both steric and electronic properties of the
HRpz ligand, giving rise to a rich and versatile chemistry.
However, the introduction of these ligands in the chemis-
try of half-sandwich arene complexes[6,7] is somewhat lim-
ited and, in the case of ruthenium and osmium, involves
the preparation of oxine [M(η6-p-cymene)(oxine)(Hazole)]+
Results and Discussion
Synthesis of Complexes
Dichloro complexes of ruthenium and osmium MCl2(η6-
p-cymene)L, containing either phosphite or isocyanide as
supporting ligands, react with the pyrazoles, HRpz, in the
presence of NaBPh4, to give the pyrazole complexes
[MCl(η6-p-cymene)(HRpz)L]BPh4 (1–8), which were iso-
lated as yellow solids and characterised (Scheme 1).
(M
=
Ru, Os) or amidine [Ru(η6-p-cymene)L(3,5-
HRRЈpz)]2+ (L = amidine) derivatives[8] containing HRpz
as a ligand. These studies have been carried out in an at-
tempt to prepare metal-based compounds with anticancer
activity.[9] Heterodinuclear complexes of the type [(η6-p-
cymene)OsCl(μ-pz)2M(COD)] (M = Rh, Ir; COD = 1,5-cyclo-
octadiene) as well as mono-[MCl2(η6-p-cymene)(HRpz)]
and bispyrazole derivatives [MCl(η6-p-cymene)(HRpz)2]+
(M = Ru, Os) are also known.[8b,10]
We are interested in the chemistry of half-sandwich arene
complexes of RuII and OsII and have recently reported the
synthesis and reactivity of diazoalkane [MCl(N2CAr1Ar2)-
[a] Dipartimento di Chimica, Università Ca’ Foscari Venezia,
Dorsoduro 2137, 30123 Venezia, Italy
[b] Departamento de Química Inorgánica, Universidade de Vigo,
Facultade de Química, Edificio de Ciencias Experimentais,
36310 Vigo, Galicia, Spain
Scheme 1. M = Ru (1, 2, 6), Os (3–5, 7, 8); R = H (1, 3, 6, 7), 3-
Me (2, 4, 8), 3,5-Me2 (5); L = P(OEt)3 (a), PPh(OEt)2 (b), PPh2OEt
(c) (1–5), CNtBu (6–8).
510
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Ru and Os Half-Sandwich Complexes
Crucial for successful synthesis was the use of ethanol
containing NaBPh4 as a solvent; the NaBPh4 salt probably
favours the substitution of the chloride ligand, allowing the
separation of compounds 1–8 in good yield.
The results obtained with HRpz prompted us to extend
our study to HIm to test whether related complexes could
be prepared. The dichloro complexes MCl2(η6-p-cymene)P
reacted with HIm in ethanol containing NaBPh4 to yield
the derivatives [MCl(η6-p-cymene)(HIm)P]BPh4 (9 and 10),
which were isolated as BPh4 salts and characterised
(Scheme 2).
Scheme 3. M = Ru (11), Os (12–14); R = H (11, 12, 14), 3-Me (13);
L = P (11–13) [P(OEt)3 (a), PPh(OEt)2 (b)], CNtBu (14).
Hpz units in the half-sandwich fragment which, after depro-
tonation of one NH hydrogen atom of HRpz, yields the
final pyrazole–pyrazolate derivative.
The easy synthesis of half-sandwich azole complexes 1–
14 with phosphite or isocyanide supporting ligands
prompted us to extend our studies to the carbonyl precur-
sors MCl2(η6-p-cymene)(CO). Results showed that the ru-
thenium complex RuCl2(η6-p-cymene)(CO) reacts with
both Hpz and HIm to give bisazole complexes [RuCl(η6-p-
cymene)(HRpz)2]+ (15 and 16) and [RuCl(η6-p-cymene)-
(HIm)2]+ (17), which were isolated in good yield and char-
acterised (Scheme 4).
Scheme 2. M = Ru (9), Os (10); L = P(OEt)3 (a), PPh(OEt)2 (b).
We also studied the reaction of the dichloro complexes
MCl2(η6-p-cymene)L with a large excess of azole (HRpz
and HIm) in an attempt to prepare bisazole derivatives
[M(η6-p-cymene)(HRpz)2L]2+ or [M(η6-p-cymene)(HIm)2-
L]2+. However, no bisazole complex was formed under any
of the conditions studied, and 1–8 were the only complexes
obtained. These species are therefore stable to substitution,
since neither chloride, phosphite or isocyanide ligands
could be substituted by an azole.
The acidic NH hydrogen atom of the coordinated pyr-
azole could be deprotonated in complexes 1–8 to give the
related neutral species MCl(η6-p-cymene)(pz)L containing
a pz ligand. We therefore treated the HRpz complexes 1–8
with an excess of NEt3 in an attempt to prepare the related
neutral pz complexes. However, at room temperature, the
reaction did not proceed, even after a long reaction time
in the presence of a large excess of NEt3, and the starting
compounds 1–8 were recovered unchanged. Under reflux
conditions, although some decomposition was observed, no
pz complex was isolated.
Scheme 4. R = H (15), 3-Me (16).
In contrast to the related phosphite and isocyanide pre-
cursors, the reaction of RuCl2(η6-p-cymene)(CO) proceeds
with the substitution, not only of one Cl– ligand, but also
of the CO group, yielding the bisazole complexes 15–17.
The reaction of the related osmium complex OsCl2(η6-p-
cymene)(CO) with azoles was also studied, but only intrac-
A different synthetic strategy was therefore used to pre- table mixtures of products were obtained.
pare pz complexes, involving treatment of the dichloro com-
Bispyrazole complexes of Ru and Os are known[8b,10] and
plexes MCl2(η6-p-cymene)L with an excess of HRpz and a were obtained from the reaction of a dinuclear complex
large excess of triethylamine in the presence of NaBPh4. In [MCl(μ-Cl)(η6-p-cymene)] with an excess of HRpz. The use
a mixture of ethanol and dichloromethane, the reaction of carbonyl RuCl2(η6-p-cymene)(CO) as a precursor re-
gave the new pyrazole–pyrazolate cations [M(Rpz)(η6-p- sulted in an alternative method for the synthesis of bisazole
cymene)(HRpz)L]+ (11–14), which were isolated as BPh4 derivatives.
salts and characterised (Scheme 3).
All azole complexes 1–17 were separated as yellow solids
The reaction proceeded with substitution of both stable in air and in solution of polar organic solvents, in
chloride ligands in the precursor MCl2(η6-p-cymene)L with which they behave as 1:1 electrolytes.[12] Their formulation
concurrent deprotonation of one HRpz ligand, yielding un- is supported by analytical and spectroscopic data (IR and
precedented half-sandwich complexes 11–14 containing one 1H, 13C, 31P NMR spectroscopy) and by X-ray crystal
HRpz and one Rpz molecule as ligands. Either the excess structure determinations of [RuCl(η6-p-cymene)(HRpz)-
of azole, or the excess of base are needed to introduce two {PPh(OEt)2}]BPh4 (1b), [Ru(Rpz)(η6-p-cymene)(HRpz)-
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{P(OEt)3}]BPh4 (11a) and [RuCl(η6-p-cymene)(HRpz)2]- comparison of the chemical shift values of the NH group
BPh4 (15), whose ORTEP diagrams[13] are shown in Fig- in our complexes with those of free HRpz also suggests
ures 1, 2 and 3, respectively.
iminic coordination of the azole, as observed in the solid
state (Figure 1). The attribution of the signals of the HRpz
ligand was supported by COSY experiments and by com-
1
parison with literature data.[3,14–17] The H NMR spectra
also contain signals of the p-cymene and phosphite or iso-
cyanide supporting ligands, confirming the proposed for-
mulation for the complexes. Lastly, the 13C NMR spectra
confirm the presence of the HRpz ligand, and heteronuc-
lear multiple quantum coherence (HMQC) and heteronuc-
lear multiple bond coherence (HMBC) experiments allow
the attribution of the signals, as reported in the Exp. Sec-
tion.
In contrast with the other HRpz complexes, the 1H
NMR spectra of the methylpyrazole derivatives 2a, 2b and
4b show two signals for both NH protons at 11.55–
10.84 ppm and the methyl substituents between 2.38 and
1.99 ppm. Two sharp singlets also appear in the 31P{1H}
NMR spectra, suggesting the presence of two species, prob-
ably isomers. Both species present in 2a, 2b and 4b may be
complexes containing 3-Me-HRpz and 5-Me-HRpz,
formed by the exchange of the nitrogen sites of the 3-meth-
ylpyrazole ligand. Isomerisation of pyrazole substituents on
a metal centre has been observed previously,[14a,17a] and
these precedents support the proposed formulation for our
half-sandwich complexes 2a, 2b and 4b (Scheme 5).
Figure 1. ORTEP view of one of the cations found in the asymmet-
ric unit for complex 1b, drawn at 30% probability level.
Figure 2. ORTEP view of the cation of complex 11a, drawn at 30%
probability level.
Scheme 5.
The IR spectra of HIm complexes 9 and 10 show a me-
dium intensity band at 3336–3312 cm–1, due to the νNH of
1
the coordinated HIm group. H NMR spectra confirm the
presence of the azole ligand, showing a broad singlet at
8.25–8.00 ppm of the NH proton and three signals between
7.16 and 6.11 ppm of the CH hydrogen atom of the HIm
group. Further support for the formulation proposed for
complexes 9 and 10 came from 13C NMR spectra, which,
along with the signals of p-cymene, phosphite and BPh4,
showed three resonances between 140.3 and 117.9 ppm, at-
tributed to the three HIm carbon atoms. 31P{1H} NMR
spectra appear as sharp singlets fitting the proposed formu-
lation for the complexes.
Figure 3. ORTEP view of the cation of complex 15, drawn at 30%
probability level.
At room temperature, 1H NMR spectra of 11–14 did not
show any signal attributable to the NH proton of HRpz.
The IR spectra of the HRpz complexes 1–8 show me- However, when the sample temperature was lowered to
dium intensity bands at 3351–3238 cm–1, attributed to the –40 °C, a broad signal at 19.14–15.79 ppm appeared, which
νNH of the HRpz ligand. A strong band at 2192–2174 cm–1 was assigned to the NH proton of HRpz involved in a N–
of the νCN of tBu isocyanide is also observed in the isocy- H···N hydrogen bond. Classical inter- or intramolecular hy-
anide complexes 6–8. However, the presence of the azole drogen bonds can shift the HRpz NH signal to higher fre-
ligands is supported by 1H NMR spectra, which show both quencies,[3,4,10,14,17a] as observed for free HRpz involved in
a sloas [fc?>the NH of the HRpz unit, and signals between extensive intermolecular N–H···N interactions, and thus
7.50 and 5.91 ppm of the HRpz CH hydrogen atoms. A confirms the existence in solution of a type II geometry
512
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Eur. J. Inorg. Chem. 2011, 510–520

Ru and Os Half-Sandwich Complexes
(Scheme 3), with one HRpz and one Rpz ligand, as ob- Table 1. Selected bond lengths [Å] and angles [°].
served in the solid state (Figure 2). Beside the signals of the
[a]
1b_mole 1 1b_mole 2 11a
15
1
supporting phosphite or isocyanide ligands, the H NMR
Coordination bond
spectra showed three resonances at 7.77–6.02 ppm attrib-
lengths
uted to the CH hydrogen atoms of HRpz. It is worth noting
Ru–CT
Ru–P
Ru–Cl
1.7128(10) 1.7107(9) 1.7398(7) 1.6796(4)
that only one set of signals for H3, H4 and H5 protons of
the two HRpz groups were observed in the proton spectra,
even at –80 °C, indicating that the two HRpz ligands shar-
ing a hydrogen atom in a N–H···N arrangement were mag-
netically equivalent. The 13C NMR spectra also show only
one set of signals for the three C3, C4 and C5 carbon reso-
nances of HRpz, fitting the proposed formulation for the
pyrazole–pyrazolate derivatives.
2.296(4)
2.404(3)
2.290(4)
2.399(3)
2.260(2)
2.4212(11)
2.112(4)
2.123(4)
2.201(4)
2.178(4)
2.170(4)
2.197(4)
2.174(4)
2.185(4)
Ru–N(1)
Ru–N(2)
Ru–C(1)
Ru–C(2)
Ru–C(3)
Ru–C(4)
Ru–C(5)
Ru–C(6)
2.046(10) 2.067(10) 2.076(6)
2.093(7)
2.258(14) 2.286(12) 2.311(8)
2.242(14) 2.263(15) 2.183(8)
2.180(13) 2.158(17) 2.196(7)
2.247(13) 2.218(14) 2.230(8)
2.162(12) 2.149(14) 2.207(7)
2.193(12) 2.189(12) 2.259(7)
The IR spectra of the bispyrazole complexes [RuCl(η6-p-
cymene)(HRpz)2]BPh4 (15 and 16) show two medium inten- Coordination bond
sity bands at 3340–3261 cm–1, attributed to the νNH of the
angles
1
two azole ligands. The H NMR spectra show the charac-
teristic broad signal of the NH of the HRpz at 11.08–10.53
ppm and related signals of the CH hydrogen atoms at 7.52–
5.97 ppm, confirming the presence of HRpz ligands. Two
singlets at δ = 2.17 and 2.13 ppm of the two methyl substit-
N(1)–Ru–Cl
N(2)–Ru–Cl
N(1)–Ru–N(2)
N(1)–Ru–P
N(2)–Ru–P
P–Ru–Cl
CT–Ru–N(1)
CT–Ru–N(2)
CT–Ru–P
87.4(3)
86.4(3)
87.7(2)
86.8(3)
87.42(10)
87.39(10)
84.74(14)
90.6(3)
89.09(18)
86.51(18)
84.37(13) 84.02(13)
128.1(3) 127.1(2)
1
125.16(17) 128.77(10)
125.51(18) 128.78(10)
uents of the HRpz in the H NMR spectrum of 16 were
also observed. The 13C NMR spectra confirm the formula-
tion proposed for complexes 15 and 16 showing both the
signals of p-cymene and those of the three carbon reso-
nances of azole groups at δ = 144.09–109.12 ppm. The IR
129.97(10) 130.82(10) 127.82(7)
125.89(9) 125.80(9)
CT–Ru–Cl
125.56(3)
Pyrazole bond
angles
1
spectra (νNH = 3304 cm–1) and H NMR spectra of com-
C(13)–N(11)–N(12) 100.8(10) 102.6(10) 108.3(7)
104.3(4)
131.4(3)
124.2(3)
104.2(4)
130.5(3)
124.3(3)
plex 17 support the presence of the azole ligands in a type
III geometry (Scheme 4), similar to those found in the solid
state for the related HRpz complex 15.
C(13)–N(11)–Ru
N(12)–N(11)–Ru
C(23)–N(21)–N(22)
C(23)–N(21)–Ru
N(22)–N(21)–Ru
132.9(8)
126.3(7)
132.1(8)
125.3(7)
127.9(6)
123.5(5)
105.1(8)
130.2(7)
124.5(6)
[a] Labelling in coordination sphere of this table was standardised:
N(1) and/or N(2) are the nitrogen donor atoms of the pyrazole or
pyrazolate rings, and C(1) to C(6) are the carbons atoms of the p-
cymene rings. CT represents the centroid of the benzene ring in the
p-cymene ligand.
X-ray Crystal Structures
The structures of 1b, 11a and 15 consist of a tetraphen-
ylborate anion and cation formed by a ruthenium atom η6-
coordinated to a p-cymene molecule, and to three donor
atoms, leading to the formation of a “three-legged piano
stool” structure. Of these ligands, one is anionic and the
other two are neutral. For 1b, the ligands forming the “legs” of 1.712(1), 1.6796(4) and 1.7398(7) Å for 1b (average of
are an anionic chlorine atom, one P-donor diethoxyphenyl- two molecules), 15 and 11a, respectively. These values are
phosphane ligand and a neutral N-donor HRpz ligand; for consistent with distances reported for other p-cymene ru-
11a, the anionic ligand is a N-donor pz and the other two thenium(II). complexes.[11b,11c] The benzene ring of the p-
are a N-donor neutral HRpz ligand and a P-donor tri- cymene is more or less planar, with a root mean square
ethoxyphosphane; for 15, the three ligands are one anionic (rms) deviation of 0.029 (average) for 1b, 0.021 for 11a and
chloride ligand and two neutral N-donor HRpz ligands. 0.005 for 15. These differences are due the different trans
The geometry of the complexes is octahedral and marked influence of the ligands, with a large trans influence of the
by near 90° values for angles between “legs”, as shown in P donor ligand and a similar influence of the N and Cl
Table 1. Expected angles between the centroid and the donor ligands. Consequently, the large C–Ru bond lengths
“legs” for the regular half-sandwich are 125.26°. The values are those pseudo-trans to the P donor ligand in 1b and 11a.
found in 1b, 11a and 15 are close to this value, except for However, the orientation of the p-cymene ligand in three
those of the phosphorus donor ligands, which are about 5° complexes is such that donor atoms in the “legs” may be
larger as a consequence of the expected cone angle of this considered staggered with the Ru–C bonds (see Figure 4)
kind of ligand.[18]
and this effect is consequently lowered. In 1b, the phos-
The average Ru–Cp-cymene bond lengths are 2.212(1) Å for phorus atom may be considered as trans to a carbon atom
1b (average of two molecules), 2.184(4) Å for 15 and [labelled as C(22) and C(52) in each molecule], but in 11a
2.231(8) Å for 11a, with Ru–centroid arene ring distances it is clearly trans to the C(1)–C(6) bond.
Eur. J. Inorg. Chem. 2011, 510–520
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G. Albertin, S. Antoniutti, J. Castro, S. García-Fontán
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Figure 4. View of the three cations through the Ru–centroid axis.
For 1b and 11a, the Ru–P bond lengths, 2.293(4) In addition, the HRpz ligand is implicated in an intramo-
(average) and 2.260(2) Å, respectively, are comparable with lecular hydrogen bond with the chloride bound to the same
those found in other related cationic arene ruthenium(II) metal atom. The geometrical parameters for this interaction
compounds.[11b,11c] In 1b and 15, the Ru–Cl bond lengths, are listed in Table 2.
2.402(3) (average) and 2.421(1) Å, respectively, are of the
same order as in related cationic arene ruthenium(II) com-
pounds.[11b,11c,19]
In compound 1b, the Ru–N bond length is on average
2.06(1) Å Ϫ a very short value. To the best of our knowl-
edge, it is the shortest value for a monodentate HRpz ligand
bonded to a RuII atom.[20] A slightly longer value is found
for nitrosyl RuII complexes,[21] [RuCl2(HRpz)2(tmeda)][22]
and [Ru(p-cymene)(pz)(HRpz)2]+.[10d] The Ru–N bond
lengths in 11a are 2.076(6) Å for the anionic pz ligand and
2.093(7) Å for the neutral Hpz ligand, comparable with
those mentioned in the literature.[19,22,23] The bond length
Figure 5. View of the π–π stacking in 1b.
for the anionic ligand is only about 0.02 Å shorter than
with the neutral HRpz ligand. Since other electronic effects,
such as the trans influence, are similar in both ligands, the
small difference suggests some degree of exchange of the
proton between the two ligands.[17a,24] A rather short intra-
molecular hydrogen bond between the two ligands is found,
with an N–N distance of only 2.58(1) Å.[24b,14] In 15, the
Ru–N bond length is on average 2.118(4) Å, slightly longer
than those found for 11b, [RuCl(p-cymene)(Me2Hpz)-
(PPh2OH)]+[25] and [Ru(p-cymene)(pz)(HRpz)2]+,[10d] but
shorter than those found in neutral [RuX2(PPh3)2(HRpz)2]
(X = Cl–, NCS–).[19,23]
Table 2. Hydrogen bond lengths [Å] and angles [°].
D–H···A
d(D–H) d(H···A) d(D···A)
Ͻ(DHA)
1b
N(12)–H(12)···Cl(1)
0.86
2.49
2.49
3.040(9)
3.043(10) 122.8
122.3
N(22)–H(22A)···Cl(2) 0.86
11a
N(22)–H(2N)···N(12) 0.86
1.85
2.580(10) 141.0
15
As reported previously,[17a] the two heterocyclic ligands
form a dihedral angle of 20.3(4)°, partly due the intramolec-
ular hydrogen bond, although the regularity of the coordi-
nation geometry is not affected, as the angle formed by the
metal and the two cyclic ligands is 90.6(3)°. It is also worth
noting that the geometrical parameters of both HRpz and
N(22)–H(2)···Cl
N(12)–H(1)···Cl
N(22)–H(2)···Cli
0.98(5)
0.88(7)
0.98(5)
2.41(5)
2.38(7)
2.60(5)
3.112(4)
3.053(5)
3.292(4)
128(4)
134(6)
128(3)
Symmetry operation, i: 1 –x, 1 –y, 1 –z
In 15, both HRpz ligands are almost perpendicular, with
pz ligands are similar, and the C–N–Ru and N–N–Ru bond dihedral angles between best planes (rms of 0.002 for both)
angles do not show significant differences (see also supple- of 88.3(2)°. They are also interconnected through a pair of
mentary crystallographic material).
hydrogen bonds through the chlorine atom. This double
In 1b, the susbtituents of the phosphonite ligand are or- bond contrasts with that found in the neutral rhenium(I)
ganised in such a way that the phenyl ring and the HRpz complex [Re(CO)3(HRpz)2Br] with only one hydrogen in-
ligand are implicated in a π–π stacking interaction, with teraction.[14] Also, the lack of this interaction in
dihedral angles of 21.3(6) and 14.7(5)° and distances be- [RuCl2(HRpz)2(tmeda)][22] and [RuCl(η6-C6Me6)(MeH-
tween centroids of 3.6831(4) and 3.4631(4) Å (see Figure 5). Rpz)2][9] is surprising. In addition, in 15 one of the hydro-
514
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© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2011, 510–520

Ru and Os Half-Sandwich Complexes
the highest available purity and used as received. Infrared spectra
were recorded with a Perkin–Elmer Spectrum One FT-IR spectro-
photometer. NMR spectra (1H, 31P, 13C) were obtained with
AC200 or AVANCE 300 Bruker spectrometers at temperatures be-
tween –80 and +30 °C, unless otherwise noted. 1H and 13C spectra
are referenced to internal tetramethylsilane; 31P{1H} chemical
shifts are reported with respect to 85% H3PO4, with downfield
shifts considered positive. The COSY, HMQC and HMBC NMR
experiments were performed using their standard programs. The
SwaN-MR and iNMR software packages[27] were used to treat
NMR spectroscopic data. The conductivity of 10–3 moldm–3 solu-
tions of the complexes in CH3NO2 at 25 °C were measured with a
Radiometer CDM 83. Elemental analyses were determined in the
Microanalytical Laboratory of the Dipartimento di Scienze Farma-
ceutiche of the University of Padua, Italy.
gen bonds is bifurcated with a neighbouring cation re-
sulting in the formation of a dimer (see Figure 6 and
Table 2).
Synthesis of Complexes: Complexes MCl2(η6-p-cymene)L [L =
P(OEt)3, PPh(OEt)2, PPh2OEt], MCl2(η6-p-cymene)(CNtBu) and
MCl2(CO)(η6-p-cymene) (M = Ru, Os) were prepared following
previously reported methods.[28]
[MCl(η6-p-cymene)(HRpz)L]BPh4 (1–5) [M = Ru (1, 2), Os (3–5);
R = H (1, 3), 3-Me (2, 4), 3,5-Me2 (5); L = P(OEt)3 (a), PPh-
(OEt)2 (b), PPh2OEt (c)]: In a 25 mL three-necked round-bottomed
flask were placed the appropriate MCl2(η6-p-cymene)L complex
(0.2 mmol), a slight excess of the appropriate HRpz (0.22 mmol),
an excess of NaBPh4 (0.3 mmol, 0.103 g) and ethanol (4 mL). The
reaction mixture was stirred for 24 h and the yellow solid that sepa-
rated was collected by filtration and recrystallised from CH2Cl2
and ethanol; yield 124 mg (75%) for 1a, 123 mg (72%) for 1b,
135 mg (76%) for 1c, 126 mg (75%) for 2a, 125 mg (72%) for 2b,
137 mg (75%) for 3a, 146 mg (77%) for 3b, 142 mg (72%) for 4b,
143 mg (76%) for 5a.
Figure 6. View of the superstructure of 15.
Conclusions
In this paper, we report the reactivity of p-cymene com-
plexes MCl2(η6-p-cymene)L, containing either phosphite,
isocyanide or CO ligands, towards Hpz and HIm molecules,
which allowed three different types of azole complexes to
be obtained: HRpz [MCl(η6-p-cymene)(HRpz)L]BPh4 and
HIm [MCl(η6-p-cymene)(HIm)L]BPh4 cations, unprece-
dented half-sandwich pyrazole–pyrazolate [M(Rpz)(η6-p-
cymene)(HRpz)L]BPh4 derivatives and bisazole [MCl(η6-p-
cymene)(HRpz)2]BPh4 or [MCl(η6-p-cymene)(HIm)2]BPh4
complexes. X-ray crystal structure determination for each
of the three types of compounds also allowed interesting
comparisons of the three half-sandwich p-cymene azole
geometries. The evaluation of the Ru–Nazole bond length
when ancillary ligands were excharged was remarkable.
With chloride and PPh(OEt)2, a very short Ru–Nazole bond
length is observed. With PPh(OEt)2 and an anionic pz li-
gand, there were two Ru–N bonds, longer than in preceding
complexes and similar to each other, due to the exchange
of the hydrogen atom. Lastly, with chloride and another
neutral HRpz ligand, the Ru–Nazole bond lengths were
longer, but within the range of literature values.[14]
1a: IR (KBr pellet): ν
= 3272 (m) cm–1. 1H NMR (CD2Cl2,
˜
NH
25 °C): δ = 11.58 (br. s, 1 H, NH), 7.33–6.89 (m, 20 H, BPh4), 7.50
(d, 1 H, H5 HRpz), 7.40 (d, 1 H, H3 HRpz), 6.45 (t, 1 H, H4
HRpz), 5.52, 5.46, 5.39, 5.21 (d, 4 H, Ph p-cym), 3.88, 3.80 (m, 6
H, CH2), 2.68 (m, 1 H, CH iPr), 2.08 (s, 3 H, CH3 p-cym), 1.20 (t,
9 H, CH3 phos), 1.18 (m, 6 H, CH3 iPr) ppm. 31P{1H} NMR
(CD2Cl2, 25 °C): δ = 113.8 (s) ppm. 13C{1H} NMR (CD2Cl2,
25 °C): δ = 165–122 (m, BPh4), 146.4 (s, C3 HRpz), 132.5 (s, C5
HRpz), 116.9 (d, C1 p-cym), 109.3 (s, C4 HRpz), 105.3 (d, C4 p-
cym), 90.56, 89.28 (d, C3 p-cym), 89.78, 88.06 (d, C2 p-cym), 63.9
(d, CH2), 31.2 (s, CH iPr), 22.1, 22.0 (s, CH3 iPr), 18.8 (s, CH3 p-
cym), 16.2 (d, CH3 phos). ΛM
=
52.9 Ω–1 mol–1 cm2.
C43H53BClN2O3PRu (824.20): calcd. C 62.66, H 6.48, Cl 4.30, N
3.40; found C 62.48, H 6.35, Cl 4.21, N 3.33.
1b: IR (KBr pellet): ν
= 3272 (m) cm–1. 1H NMR (CD2Cl2,
˜
NH
25 °C): δ = 11.37 (br. s, 1 H, NH), 7.45–6.88 (m, 25 H, Ph), 6.28
(t, 1 H, H4 HRpz), 5.53, 5.45, 5.33, 5.17 (d, 4 H, Ph p-cym), 4.02,
3.90 (m, 4 H, CH2), 2.69 (m, 1 H, CH iPr), 2.01 (s, 3 H, CH3 p-
cym), 1.35 (m, 6 H, CH3 iPr), 1.17 (t, 6 H, CH3 phos) ppm.
31P{1H} NMR (CD2Cl2, 25 °C):
δ = 143.1 (s). ΛM =
54.2 Ω–1 mol–1 cm2. C47H53BClN2O2PRu (856.24): calcd. C 65.93,
Experimental Section
H 6.24, Cl 4.14, N 3.27; found C 66.05, H 6.17, Cl 4.01, N 3.35.
General: All synthetic work was carried out in an inert atmosphere
(Ar, N2) using standard Schlenk techniques or a vacuum atmo-
sphere dry-box. All solvents were dried with appropriate drying
agents, degassed on a vacuum line and distilled into vacuum-tight
storage flasks. RuCl3·3H2O and OsO4 were obtained from Pressure
Chemical Co. (USA) Products and used as received. Phosphites,
PPh(OEt)2 and PPh2OEt, were prepared by the method reported
by Rabinowitz and Pellon.[26] P(OEt)3 (Aldrich) was used as re-
ceived. Other reagents were purchased from commercial sources in
1c: IR (KBr pellet): ν
= 3270 (m) cm–1. 1H NMR (CD2Cl2,
˜
NH
25 °C): δ = 11.34 (br. s, 1 H, NH), 7.58–6.88 (m, 30 H, Ph), 7.25
(d, 1 H, H3 HRpz), 6.28 (t, 1 H, H4 HRpz), 5.49, 5.34, 5.16 (d, 4
H, Ph p-cym), 3.74, 3.70 (m, 2 H, CH2), 2.68 (m, 1 H, CH iPr),
2.08 (s, 3 H, CH3 p-cym), 1.28 (t, 3 H, CH3 phos), 1.19 (d, 6 H,
CH3 iPr) ppm. 31P{1H} NMR (CD2Cl2, 25 °C): δ = 125.8 (s). ΛM
= 54.8 Ω–1 mol–1 cm2. C51H53BClN2OPRu (888.29): calcd. C 68.96,
H 6.01, Cl 3.99, N 3.15; found C 69.11, H 5.96, Cl 3.81, N 3.02.
Eur. J. Inorg. Chem. 2011, 510–520
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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515

G. Albertin, S. Antoniutti, J. Castro, S. García-Fontán
FULL PAPER
2a: IR (KBr pellet): ν
= 3238 (m) cm–1. 1H NMR (CD2Cl2, 7.15, 7.06 (br., 1 H, H3 or H5 HRpz), 5.99, 5.91 (t, 1 H, H4 HRpz),
˜
NH
25 °C): δ = 11.43, 11.25 (br. s, 1 H, NH), 7.55 (br., 1 H, H3 HRpz), 5.63, 5.56, 5.53, 5.37 (d, 4 H, Ph p-cym), 4.03, 3.85 (m, 4 H, CH2),
7.31–6.88 (m, 20 H, BPh4), 7.27 (d, 1 H, H5 HRpz), 6.32, 6.22 (t,
1 H, H4 HRpz), 5.54, 5.47, 5.39, 5.23 (d, 4 H, Ph p-cym), 3.89,
3.82 (m, 6 H, CH2), 2.68 (m, 1 H, CH iPr), 2.33, 2.20 (s, 3 H, CH3
HRpz), 2.15, 2.08 (s, 3 H, CH3 p-cym), 1.22 (t, 9 H, CH3 phos),
2.67 (m, 1 H, CH iPr), 2.39, 2.18 (s, 3 H, CH3 p-cym), 2.14, 2.01
(s, 3 H, CH3 HRpz), 1.38, 1.34 (t, 6 H, CH3 phos), 1.08 (d, 6 H,
CH3 iPr) ppm. 31P{1H} NMR (CD2Cl2, 25 °C): δ = 99.5, 98.9 (s)
ppm. 13C{1H} NMR (CD2Cl2, 25 °C): δ = 165–122 (m, Ph), 153.16,
1.19 (m, 6 H, CH3 iPr) ppm. 31P{1H} NMR (CD2Cl2, 25 °C): δ = 141.80 [s, C3(CH3) and C5(CH3) HRpz], 146.54, 131.98 (C3 and
115.1 (s); 113.7 (s) ppm. 13C{1H} NMR (CD2Cl2, 25 °C): δ = 165–
122 (m, Ph), 155.1, 143.5 (s, C5 HRpz), 147.3, 132.8 (s, C3 HRpz), 99.98, 95.58 (d, C4 p-cym), 82.10, 79.22 (d, C2 p-cym), 80.80, 80.73,
C5), 116.90, 111.66 (d, C1 p-cym), 108.79, 108.73 (s, C4 HRpz),
110.6 (d, C1 p-cym), 108.9 (d, C4 HRpz), 104.5 (d, C4 p-cym),
90.70, 89.52 (d, C3 p-cym), 89.84, 88.14 (d, C2 p-cym), 89.17, 89.15
(d, C2 HRpz), 88.59 (d, C3 HRpz), 87.56 (d, C2 HRpz), 63.9 (d,
CH2), 31.4, 31.3 (s, CH iPr), 22.7, 22.6, 22.2, 22.1 (s, CH3 iPr),
80.13, 78.19 (d, C3 p-cym), 64.3 (m, CH2), 31.40, 31.15 (s, CH iPr),
22.51, 22.02, 20.59 (s, CH3 iPr), 18.73, 18.53 (s, CH3 p-cym), 16.54,
11.01 (s, 3-CH3 and 5-CH3 HRpz), 16.2 (m, CH3 phos). ΛM
=
51.9 Ω–1 mol–1 cm2. C48H55BClN2O2OsP (959.43): calcd. C 60.09,
18.8, 18.7 (s, CH3 p-cym), 16.2 (d, CH3 phos), 15.2, 11.2 (s, CH3 H 5.78, Cl 3.70, N 2.92; found C 59.96, H 5.80, Cl 3.53, N 2.83.
HRpz). ΛM = 51.6 Ω–1 mol–1 cm2. C44H55BClN2O3PRu (838.23):
calcd. C 63.05, H 6.61, Cl 4.23, N 3.34; found C 63.23, H 6.53, Cl
4.07, N 3.23.
5a: IR (KBr pellet): ν
= 3323 (s) cm–1. 1H NMR (CD2Cl2,
˜
NH
25 °C): δ = 11.20 (br. s, 1 H, NH), 7.32–6.88 (m, 20 H, BPh4), 6.10
(d, 1 H, H4 HRpz), 5.66, 5.62, 5.56, 5.45 (d, 4 H, Ph p-cym), 3.88,
3.77 (m, 6 H, CH2), 2.56 (m, 1 H, CH iPr), 2.34, 2.15 (s, 6 H, CH3
HRpz), 2.28 (s, 3 H, CH3 p-cym), 1.25, 1.16 (d, 6 H, CH3 iPr), 1.19
(t, 9 H, CH3 phos) ppm. 31P{1H} NMR (CD2Cl2, 25 °C): δ = 71.39
(s) ppm. 13C{1H} NMR (CD2Cl2, 25 °C): δ = 165–122 (m, BPh4),
155.18 (s, C3 HRpz), 143.40 (s, C5 HRpz), 116.37 (d, C1 p-cym),
108.29 (s, C4 HRpz), 96.76 (d, C4 p-cym), 81.65, 80.17 (d, C2 p-
cym), 80.87, 79.34 (d, C3 p-cym), 63.47 (d, CH2), 31.09 (s, CH iPr),
22.77, 22.75 (s, CH3 iPr), 21.10 (s, CH3 p-cym), 16.11 (d, CH3
phos), 15.83, 11.04 (s, CH3 HRpz). ΛM = 53.0 Ω–1 mol–1 cm2.
C45H57BClN2O3OsP (941.41): calcd. C 57.41, H 6.10, Cl 3.77, N
2.98; found C 57.28, H 6.16, Cl 3.59, N 2.95.
[MCl(η6-p-cymene)(HRpz)(CNtBu)]BPh4 (6–8) [M = Ru (6), Os (7,
8); R = H (6, 7), 3-Me (8)]: These complexes were prepared in the
same way as the related phosphite derivatives 1–5 described above
using MCl2(η6-p-cymene)(CNtBu) as a precursor; yield 104 mg
(70%) for 6, 120 mg (72%) for 7, 123 mg (73%) for 8.
2b: IR (KBr pellet): ν
= 3289 (m), 3261 (s) cm–1. 1H NMR
˜
NH
(CD2Cl2, 25 °C): δ = 11.26, 10.84 (br. s, 1 H, NH), 7.40–6.88 (m,
25 H, Ph), 7.12 (d, 1 H, H3 HRpz), 6.88 (d, 1 H, H5 HRpz), 6.04,
6.00 (t, 1 H, H4 HRpz), 5.56, 5.48, 5.33, 5.19 (d, 4 H, Ph p-cym),
4.08, 3.96, 3.87 (m, 4 H, CH2), 2.73 (m, 1 H, CH iPr), 2.20, 2.04
(s, 3 H, CH3 p-cym), 2.19, 1.99 (s, 3 H, CH3 HRpz), 1.39, 1.37 (t,
6 H, CH3 phos), 1.20 (m, 6 H, CH3 iPr) ppm. 31P{1H} NMR
(CD2Cl2, 25 °C): δ = 145.2 (s); 143.4 (s) ppm. 13C{1H} NMR
(CD2Cl2, 25 °C): δ = 165–122 (m, Ph), 153.7, 131.5 (s, C5 HRpz),
146.3, 142.5 (s, C3 HRpz), 120.5 (d, C1 p-cym), 109.0, 108.7 (s, C4
HRpz) 105.5, 102.6 (d, C4 p-cym), 90.7, 90.0, 89.2 (d, C3 p-cym),
89. 2, 86.5, 87.6, 87.3 (d, C2 p-cym), 65.2, 64.9 (d, CH2), 31.4 (s,
CH iPr), 22.3, 21.9, 20.64 (s, CH3 iPr), 18.75, 18.60 (s, CH3 p-cym),
16.2 (m, CH3 phos), 15.9, 11.0 (s, 3-CH3 and 5-CH3 HRpz). ΛM
=
53.0 Ω–1 mol–1 cm2. C48H55BClN2O2PRu (870.27): calcd. C 66.25,
H 6.37, Cl 4.07, N 3.22; found C 66.39, H 6.44, Cl 4.24, N 3.07.
3a: IR (KBr pellet): ν
= 3351 (m) cm–1. 1H NMR (CD2Cl2,
˜
NH
6: IR (KBr pellet): ν
= 3270 (m), νCN = 2192 (s) cm–1. 1H NMR
˜
˜
NH
25 °C): δ = 11.79 (br. s, 1 H, NH), 7.78 (br., 1 H, H5 HRpz), 7.32–
6.86 (m, 20 H, BPh4), 6.44 (t, 1 H, H4 HRpz), 5.61, 5.56, 5.40,
5.32 (d, 4 H, Ph p-cym), 3.87, 3.80 (m, 6 H, CH2), 2.61 (m, 1 H,
CH iPr), 2.19 (s, 3 H, CH3 p-cym), 1.21, 1.19 (d, 6 H, CH3 iPr),
1.20 (t, 9 H, CH3 phos); (–70 °C) 7.44 (br. s, H5 HRpz), 7.37 (br.
s, H3 HRpz), 6.42 (br. s, H4 HRpz) ppm. 31P{1H} NMR (CD2Cl2,
25 °C): δ = 70.1 (s) ppm. 13C{1H} NMR (CD2Cl2, 25 °C): δ = 165–
122 (m, BPh4), 146.45 (s, C5 HRpz), 131.77 (s, C3 HRpz), 110.3
(d, C1 p-cym), 109.29 (s, C4 HRpz), 99.9 (d, C4 p-cym), 82.5, 80.35
(d, C2 p-cym), 81.40, 80.01 (d, C3 p-cym), 63.55 (d, CH2), 31.03
(s, CH iPr), 22.34, 22.18 (s, CH3 iPr), 18.57 (s, CH3 p-cym), 16.16
(d, CH3 phos). ΛM = 49.7 Ω–1 mol–1 cm2. C43H53BClN2O3OsP
(913.36): calcd. C 56.55, H 5.85, Cl 3.88, N 3.07; found C 56.35,
H 5.89, Cl 3.71, N 3.16.
(CD2Cl2, 25 °C): δ = 11.55 (br. s, 1 H, NH), 7.50 (d, 1 H, H5
HRpz), 7.36–6.88 (m, 20 H, BPh4), 7.32 (d, 1 H, H3 HRpz), 6.46
(t, 1 H, H4 HRpz), 5.46, 5.39, 5.29, 5.09 (d, 4 H, Ph p-cym), 2.63
(m, 1 H, CH iPr), 1.97 (s, 3 H, CH3 p-cym), 1.44 (s, 9 H, CH3 tBu),
1.25, 1.23 (d, 6 H, CH3 iPr) ppm. 13C{1H} NMR (CD2Cl2, 25 °C):
δ = 165–122 (m, BPh4), 145.7 (s, C3 HRpz), 132.9 (s, C5 HRpz),
111.5 (s, C1 p-cym), 109.35 (s, C4 HRpz), 109.09 (s, C4 p-cym),
89.67, 89.52 (s, C3 p-cym), 88.41, 87.94 (s, C2 p-cym), 60.1 (s, C
tBu), 31.9 (s, CH iPr), 30.4 (s, CH3 tBu), 22.67, 22.35 (s, CH3 iPr),
18.9 (s, CH3 p-cym). ΛM = 54.5 Ω–1 mol–1 cm2. C42H47BClN3Ru
(741.18): calcd. C 68.06, H 6.39, Cl 4.78, N 5.67; found C 67.88,
H 6.46, Cl 4.66, N 5.54.
7: IR (KBr pellet): ν = 3275 (m), νCN = 2187 (s) cm–1. 1H NMR
˜
˜
NH
= 3279 (m) cm–1. 1H NMR (CD2Cl2,
(CD2Cl2, 25 °C): δ = 11.80 (br. s, 1 H, NH), 7.50 (d, 1 H, H5
HRpz), 7.41 (br., 1 H, H3 HRpz), 7.35–6.86 (m, 20 H, BPh4), 6.43
(t, 1 H, H4 HRpz), 5.62, 5.57, 5.43, 5.28 (d, 4 H, Ph p-cym), 2.61
(m, 1 H, CH iPr), 2.07 (s, 3 H, CH3 p-cym), 1.44 (s, 9 H, CH3 tBu),
1.24, 1.23 (d, 6 H, CH3 iPr) ppm. 13C{1H} NMR (CD2Cl2, 25 °C):
δ = 165–122 (m, BPh4), 145.93 (s, C3 HRpz), 132.10 (s, C5 HRpz),
109.52 (s, C4 HRpz), 104.32 (s, C1 p-cym), 103.29 (s, C4 p-cym),
82.15, 81.60 (s, C2 p-cym), 80.44, 80.41 (s, C3 p-cym), 59.78 (s, C
tBu), 31.89 (s, CH iPr), 30.80 (s, CH3 tBu), 22.94, 22.48 (s, CH3
3b: IR (KBr pellet): ν
˜
NH
25 °C): δ = 11.71 (br. s, 1 H, NH), 7.33–6.87 (m, 25 H, Ph), 7.21
(t, 1 H, H5 HRpz), 6.17 (t, 1 H, H4 HRpz), 5.59, 5.54, 5.36, 5.33
(d, 4 H, Ph p-cym), 4.02, 3.85 (m, 4 H, CH2), 2.62 (m, 1 H, CH
iPr), 2.15 (s, 3 H, CH3 p-cym), 1.36, 1.34 (t, 6 H, CH3 phos), 1.19,
1.17 (d, 6 H, CH3 iPr) ppm. 31P{1H} NMR (CD2Cl2, 25 °C): δ =
98.8 (s) ppm. 13C{1H} NMR (CD2Cl2, 25 °C): δ = 165–122 (m,
Ph), 145.90 (s, C5 HRpz), 112.07 (d, C1 p-cym), 109.34 (d, C4 p-
cym), 82.00, 80.33 (d, C2 p-cym), 80.95, 78.60 (d, C3 p-cym), 64.47,
64.36 (d, CH2), 31.12 (s, CH iPr), 22.40, 21.98 (s, CH3 iPr), 18.50 (s,
CH3 p-cym), 16.34, 16.14 (d, CH3 phos). ΛM = 52.4 Ω–1 mol–1 cm2.
C47H53BClN2O2OsP (945.40): calcd. C 59.71, H 5.65, Cl 3.75, N
2.96; found C 59.88, H 5.77, Cl 3.57, N 2.85.
iPr), 18.63 (s, CH3 p-cym) ppm. ΛM
=
52.7 Ω–1 mol–1 cm2.
C42H47BClN3Os (830.34): calcd. C 60.75, H 5.71, Cl 4.27, N 5.06;
found C 60.54, H 5.62, Cl 4.15, N 4.91.
8: IR (KBr pellet): ν = 3334 (m), νCN = 2174 (s) cm–1. 1H NMR
˜
˜
NH
4b: IR (KBr pellet): νNH = 3273, 3261 (m) cm–1. 1H NMR (CD2Cl2,
(CD2Cl2, 25 °C): δ = 11.50 (br. s, 1 H, NH), 7.34–6.86 (m, 20 H,
˜
25 °C): δ = 11.55, 11.22 (br. s, 1 H, NH), 7.32–6.86 (m, 25 H, Ph),
BPh4), 7.27 (d, 1 H, H5 HRpz), 6.20 (d, 1 H, H4 HRpz), 5.63,
516
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© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2011, 510–520

Ru and Os Half-Sandwich Complexes
5.55, 5.45, 5.30 (d, 4 H, Ph p-cym), 2.61 (m, 1 H, CH iPr), 2.36 (s, filtration and recrystallised from CH2Cl2 and ethanol; yield 115 mg
3 H, CH3 HRpz), 2.08 (s, 3 H, CH3 p-cym), 1.44 (s, 9 H, CH3 tBu),
(67%) for 11a, 118 mg (66%) for 11b, 124 mg (65%) for 12a,
1.24 (d, H, CH3 iPr) ppm. ΛM =
6
51.2 Ω–1 mol–1 cm2. 133 mg (68%) for 12b, 135 mg (67%) for 13b.
C43H49BClN3Os (844.36): calcd. C 61.17, H 5.85, Cl 4.20, N 4.98;
found C 61.35, H 5.72, Cl 4.08, N 4.87.
11a: 1H NMR (CD2Cl2, 25 °C): δ = 7.77 (d, 2 H, H5 HRpz/pz),
7.34 (d, 2 H, H3 HRpz/pz), 7.34–6.89 (m, 20 H, BPh4), 6.39 (t, 2
H, H4 HRpz/pz), 5.47, 5.44 (d, 4 H, Ph p-cym), 3.55 (qnt, 6 H,
CH2), 2.22 (m, 1 H, CH iPr), 2.01 (s, 3 H, CH3 p-cym), 1.12 (t, 9
H, CH3 phos), 1.08 (d, 6 H, CH3 iPr); [(CD3)2CO, –70 °C]: δ =
18.15 (s, 1 H, NH) ppm. 31P{1H} NMR (CD2Cl2, 25 °C): δ = 115.8
(s) ppm. 13C{1H} NMR (CD2Cl2, 25 °C): δ = 165–121 (m, BPh4),
145.7 (s, C3 HRpz/pz), 135.8 (s, C5 HRpz/pz), 107.7 (s, C4 HRpz/
pz), 120.4 (d, C1 p-cym), 107.2 (d, C4 p-cym), 92.0 (d, C2 p-cym),
90.7 (d, C3 p-cym), 66.9 (d, CH2), 31.4 (s, CH iPr), 22.1 (s, CH3
[MCl(η6-p-cymene)(HIm)L]BPh4 (9–10) [M = Ru (9), Os (10); L =
P(OEt)3 (a), PPh(OEt)2 (b)]: These complexes were prepared ac-
cording to the method used for 1–5 described above using HIm as
a reagent; yield 128 mg (78%) for 9a, 137 mg (80%) for 9b, 140 mg
(76%) for 10a, 145 mg (77%) for 10b.
9a: IR (KBr pellet): ν
= 3312 (m) cm–1. 1H NMR (CD2Cl2,
˜
NH
25 °C): δ = 8.25 (br. s, 1 H, NH), 7.42–6.89 (m, 20 H, BPh4), 6.38,
6.30, 6.18 (d, 3 H, CH HIm), 5.33, 5.13 (m, 4 H, Ph p-cym), 3.70
(m, 6 H, CH2), 2.62 (m, 1 H, CH iPr), 2.06 (s, 3 H, CH3 p-cym),
1.19, 1.18 (t, 9 H, CH3 phos), 0.98 (d, 6 H, CH3 iPr) ppm. 31P{1H}
iPr), 18.7 (s, CH3 p-cym), 16.2 (d, CH3 phos) ppm. ΛM
=
51.9 Ω–1 mol–1 cm2. C46H56BN4O3PRu (855.82): calcd. C 64.56, H
6.60, N 6.55; found C 64.72, H 6.48, N 6.42.
NMR (CD2Cl2, 25 °C):
δ
=
163.1 (s) ppm. ΛM
=
11b: 1H NMR (CD2Cl2, 25 °C): δ = 7.38–6.53 (m, 25 H, Ph), 7.52
(d, 2 H, H5 HRpz/pz), 7.34 (d, 2 H, H3 HRpz/pz), 6.37 (t, 2 H,
H4 HRpz/pz), 5.48, 5.42 (d, 4 H, Ph p-cym), 3.79 (m, 4 H, CH2),
2.17 (m, 1 H, CH iPr), 2.05 (s, 3 H, CH3 p-cym), 1.31 (t, 6 H, CH3
phos), 0.99 (d, 6 H, CH3 iPr); [(CD3)2CO, –70 °C]: δ = 18.38 (s, 1
H, NH), 7.63 (d, 2 H, H5 HRpz/pz), 7.54 (br. s, 2 H, H3 HRpz/
pz), 7.30–6.75 (m, 25 H, Ph), 6.43 (m, 2 H, H4 HRpz/pz), 6.35,
6.06 (d, 4 H, Ph p-cym), 4.15 (m, 4 H, CH2), 3.53 (m, 1 H, CH
iPr), 2.37 (s, 3 H, CH3 p-cym), 1.38, 1.28 (t, 6 H, CH3 phos), 0.92
(d, 6 H, CH3 iPr) ppm. 31P{1H} NMR (CD2Cl2, 25 °C): δ = 144.4
(s); [(CD3)2CO, –70 °C]: δ = 144.1 (s) ppm. 13C{1H} NMR
(CD2Cl2, 25 °C): δ = 165–121 (m, BPh4), 145.1 (s, C3 HRpz/pz),
132.1 (s, C5 HRpz/pz), 121.2 (s, C1 p-cym), 107.9 (s, C4 HRpz/pz),
105.9 (s, C4 p-cym), 92.4 (d, C2 p-cym), 89.8 (d, C3 p-cym), 66.1
(d, CH2), 31.5 (s, CH iPr), 22.0 (s, CH3 iPr), 18.6 (s, CH3 p-cym),
16.5 (d, CH3 phos). ΛM = 52.5 Ω–1 mol–1 cm2. C50H56BN4O2PRu
(887.86): calcd. C 67.64, H 6.36, N 6.31; found C 67.75, H 6.47, N
6.18.
12a: 1H NMR (CD2Cl2, –70 °C): δ = 18.84 (br. s, 1 H, NH), 7.64
(d, 2 H, H5 HRpz/pz), 7.43 (d, 2 H, H3 HRpz/pz), 7.43–6.86 (m,
20 H, BPh4), 6.33 (t, 2 H, H4 HRpz/pz), 5.51, 5.47 (d, 4 H, Ph p-
cym), 3.55 (q, 6 H, CH2), 2.23 (m, 1 H, CH iPr), 2.08 (s, 3 H, CH3
p-cym), 1.11 (t, 9 H, CH3 phos), 1.10 (d, 6 H, CH3 iPr) ppm.
31P{1H} NMR (CD2Cl2, –70 °C): δ = 71.23 (s) ppm. 13C{1H}
NMR (CD2Cl2, 25 °C): δ = 165–122 (m, BPh4), 145.80 (s, C3
HRpz/pz), 134.96 (s, C5 HRpz/pz), 107.35 (s, C4 HRpz/pz), 112.8
(s, C1 p-cym), 101.1 (s, C4 p-cym), 83.34 (d, C2 p-cym), 82.33 (d,
C3 p-cym), 63.40 (d, CH2), 31.16 (s, CH iPr), 22.21 (s, CH3 iPr),
52.0 Ω–1 mol–1 cm2. C43H53BClN2O3PRu (824.20): calcd. C 62.66,
H 6.48, Cl 4.30, N 3.40; found C 62.47, H 6.56, Cl 4.19, N 3.26.
9b: IR (KBr pellet): ν
= 3322 (m) cm–1. 1H NMR (CD2Cl2,
˜
NH
25 °C): δ = 8.13 (br. s, 1 H, NH), 7.39–6.89 (m, 25 H, Ph), 6.31
(d), 6.22 (s), 6.13 (d, 3 H, CH HIm), 5.21, 5.12 (d, 4 H, Ph p-cym),
3.80 (m, 4 H, CH2), 2.52 (m, 1 H, CH iPr), 2.00 (s, 3 H, CH3 p-
cym), 1.28 (t, 6 H, CH3 phos), 0.90 (d, 6 H, CH3 iPr) ppm. 31P{1H}
NMR (CD2Cl2, 25 °C): δ = 143.5 (s) ppm. 13C{1H} NMR (CD2Cl2,
25 °C): δ = 165–123 (m, BPh4), 140.3, 131.3, 119.6 (s, CH HIm),
117.7 (d, C1 p-cym), 107.1 (d, C4 p-cym), 92.8 (d, C3 p-cym), 90.3
(d, C2 p-cym), 66.6 (d, CH2), 31.2 (s, CH iPr), 22.2, 22.0 (s, CH3
iPr), 18.1 (s, CH3 p-cym), 16.4 (d, CH3 phos) ppm. ΛM
=
53.8 Ω–1 mol–1 cm2. C47H53BClN2O2PRu (856.24): calcd. C 65.93,
H 6.24, Cl 4.14, N 3.27; found C 65.77, H 6.36, Cl 3.97, N 3.14.
10a: IR (KBr pellet): ν
= 3336 (s) cm–1. 1H NMR (CD2Cl2,
˜
NH
25 °C): δ = 8.14 (br. s, 1 H, NH), 7.40–6.88 (m, 20 H, BPh4), 7.16,
6.33 (s, 3 H, CH HIm), 5.52, 5.42, 5.28 (d, 4 H, Ph p-cym), 3.84,
3.73 (m, 6 H, CH2), 2.55 (m, 1 H, CH iPr), 2.16 (s, 3 H, CH3 p-
cym), 1.19 (d, 6 H, CH3 iPr), 1.18 (t, 9 H, CH3 phos) ppm. 31P{1H}
NMR (CD2Cl2, –60 °C):
δ
=
75.9 (s) ppm. ΛM
=
50.3 Ω–1 mol–1 cm2. C43H53BClN2O3OsP (913.36): calcd. C 56.55,
H 5.85, Cl 3.88, N 3.07; found C 56.74, H 5.69, Cl 3.75, N 2.96.
10b: IR (KBr pellet): ν
= 3321 (s) cm–1. 1H NMR (CD2Cl2,
˜
NH
25 °C): δ = 8.00 (br. s, 1 H, NH), 7.40–6.91 (m, 25 H, Ph), 7.10,
6.73, 6.11 (s, 3 H, CH HIm), 5.54, 5.52, 5.37, 5.28 (d, 4 H, Ph p-
cym), 4.05, 3.88, 3.70 (m, 4 H, CH2), 2.53 (m, 1 H, CH iPr), 2.16
(s, 3 H, CH3 p-cym), 1.36, 1.30 (t, 6 H, CH3 phos), 1.16, 1.14 (d,
6 H, CH3 iPr) ppm. 31P{1H} NMR (CD2Cl2, 25 °C): δ = 98.8 (s)
ppm. 13C{1H} NMR (CD2Cl2, 25 °C): δ = 165–122 (m, BPh4),
138.88, 130.45, 117.90 (s, CH HIm), 110.50 (d, C1 p-cym), 97.70
(d, C4 p-cym), 81.60, 81.34 (d, C2 p-cym), 81.00, 78.40 (d, C3 p-
cym), 64.35, 64.10 (d, CH2), 30.85 (s, CH iPr), 22.21, 22.15 (s, CH3
18.42 (s, CH3 p-cym), 16.12 (d, CH3 phos) ppm. ΛM
=
53.9 Ω–1 mol–1 cm2. C46H56BN4O3OsP (944.98): calcd. C 58.47, H
5.97, N 5.93; found C 58.30, H 5.84, N 5.78.
1
12b: H NMR (CD2Cl2, –70 °C): δ = 18.74 (br. s, 1 H, NH), 7.44
(d, 2 H, H5 HRpz/pz), 7.41 (d, 2 H, H3 HRpz/pz), 7.40–6.89 (m,
25 H, Ph), 6.30 (t, 2 H, H4 HRpz/pz), 5.53, 5.46 (d, 4 H, Ph p-
cym), 3.73 (m, 4 H, CH2), 2.18 (m, 1 H, CH iPr), 2.13 (s, 3 H, CH3
p-cym), 1.28 (t, 6 H, CH3 phos), 1.00 (d, 6 H, CH3 iPr) ppm.
31P{1H} NMR (CD2Cl2, –70 °C): δ = 96.4 (s) ppm. 13C{1H} NMR
(CD2Cl2, 25 °C): δ = 165–122 (m, BPh4), 145.30 (s, C3 HRpz/pz),
134.50 (s, C5 HRpz/pz), 107.55 (s, C4 HRpz/pz), 113.70 (s, C1 p-
cym), 98.50 (s, C4 p-cym), 83.64 (d, C2 p-cym), 81.23 (d, C3 p-
cym), 65.42 (d, CH2), 31.23 (s, CH iPr), 22.11 (s, CH3 iPr), 18.40 (s,
CH3 p-cym), 16.40 (d, CH3 phos) ppm. ΛM = 52.1 Ω–1 mol–1 cm2.
C50H56BN4O2OsP (977.02): calcd. C 61.47, H 5.78, N 5.73; found
C 61.63, H 5.59, N 5.65.
iPr), 18.36 (s, CH3 p-cym), 16.24 (d, CH3 phos) ppm. ΛM
=
55.4 Ω–1 mol–1 cm2. C47H53BClN2O2OsP (945.40): calcd. C 59.71,
H 5.65, Cl 3.75, N 2.96; found C 59.53, H 5.55, Cl 3.61, N 2.90.
[M(Rpz)(η6-p-cymene)(HRpz)L]BPh4 (11–13) [M = Ru (11), Os (12,
13); R = H (11, 12), 3-Me (13); L = P(OEt)3 (a), PPh(OEt)2 (b)]:
In a 25-mL three-necked round-bottomed flask were placed
MCl2(η6-p-cymene)L (0.2 mmol), an excess of HRpz (0.9 mmol),
an excess of NaBPh4 (0.36 mmol, 0.12 g), ethanol (4 mL) and
dichloromethane (8 mL). An excess of triethylamine (1.8 mmol,
0.25 mL) was added to the resulting solution, which was stirred at
room temperature for 24 h. The solvent was removed under re-
duced pressure to give an oil which was triturated with ethanol
(3 mL). A yellow solid slowly separated, which was collected by
1
13b: H NMR (CD2Cl2, –70 °C): δ = 19.14 (br. s, 1 H, NH), 7.33–
6.86 (m, 25 H, Ph), 7.24 (d, 2 H, H5 HRpz/pz), 6.02 (d, 2 H, H4
Eur. J. Inorg. Chem. 2011, 510–520
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
517

G. Albertin, S. Antoniutti, J. Castro, S. García-Fontán
FULL PAPER
HRpz/pz), 5.53, 5.47 (d, 4 H, Ph p-cym), 3.81 (m, 4 H, CH2), 2.27 15: IR (KBr pellet): νNH = 3334, 3306 (m) cm–1. 1H NMR (CD2Cl2,
˜
(m, 1 H, CH iPr), 2.21 (s, 6 H, CH3 HRpz/pz), 2.18 (s, 3 H, CH3 25 °C): δ = 11.08 (br., 2 H, NH), 7.52 (d, 2 H, H5 HRpz), 7.40–
p-cym), 1.30 (t, 6 H, CH3 phos), 1.03 (d, 6 H, CH3 iPr) ppm. 6.88 (m, 20 H, BPh4), 7.38 (d, 2 H, H3 HRpz), 6.42 (t, 2 H, H4
31P{1H} NMR (CD2Cl2, –70 °C): δ = 96.5 (s) ppm. ΛM
=
HRpz), 5.50, 5.19 (d, 4 H, Ph p-cym), 2.44 (m, 1 H, CH iPr), 1.69
(s, 3 H, CH3 p-cym), 1.10 (d, 6 H, CH3 iPr) ppm. 13C{1H} NMR
(CD2Cl2, 25 °C): δ = 165–122 (m, BPh4), 144.09 (s, C5 HRpz),
131.84 (s, C3HRpz), 109.12 (s, C4 HRpz), 104.43 (s, C1 p-cym),
101.74 (s, C4 p-cym), 85.98 (d, C2 p-cym), 82.11 (d, C3 p-cym),
31.25 (s, CH iPr), 22.22 (s, CH3 iPr), 18.35 (s, CH3 p-cym) ppm.
ΛM = 50.5 Ω–1 mol–1 cm2. C40H42BClN4Ru (726.12): calcd. C 66.16,
H 5.83, Cl 4.88, N 7.72; found C 66.01, H 5.69, Cl 4.76, N 7.61.
51.9 Ω–1 mol–1 cm2. C52H60BN4O2OsP (1005.07): calcd. C 62.14, H
6.02, N 5.57; found C 62.01, H 6.18, N 5.46.
[Os(Rpz)(η6-p-cymene)(HRpz)(CNtBu)]BPh4 (14): Complex 14 was
prepared in the same way as 11–13 using OsCl2(η6-p-cym-
ene)(CNtBu) as a precursor; yield 118 mg (65%). IR (KBr pellet):
1
ν
= 2170 (s) cm–1. H NMR (CD2Cl2, –70 °C): δ = 15.79 (s, 1
˜
CN
H, NH), 7.60 (d, 2 H, H5 HRpz/pz), 7.38–6.86 (m, 20 H, BPh4),
7.35 (d, 2 H, H3 HRpz/pz), 6.31 (t, 2 H, H4 HRpz/pz), 5.58, 5.41
(d, 4 H, Ph p-cym), 2.45 (m, 1 H, CH iPr), 1.89 (s, 3 H, CH3 p-
16: IR (KBr pellet): νNH = 3350, 3261 (m) cm–1. 1H NMR (CD2Cl2,
˜
25 °C): δ = 10.53 (br. s, 2 H, NH), 7.31–6.86 (m, 20 H, BPh4), 5.97
(s, 2 H, H4 HRpz), 5.94, 5.30 (d, 4 H, Ph p-cym), 2.71 (m, 1 H,
CH iPr), 2.17, 2.13 (s, 12 H, CH3 HRpz), 1.57 (s, 3 H, CH3 p-cym),
cym), 1.45 (s, 9 H, CH3 tBu), 1.22 (d, 6 H, CH3 iPr) ppm. ΛM
=
54.6 Ω–1 mol–1 cm2. C45H50BN5Os (861.95): calcd. C 62.70, H 5.85,
N 8.12; found C 62.57, H 5.80, N 8.01.
1.14 (d, 6 H, CH3 iPr) ppm. ΛM =
53.3 Ω–1 mol–1 cm2.
C44H50BClN4Ru (782.23): calcd. C 67.56, H 6.44, Cl 4.53, N 7.16;
found C 67.69, H 6.52, Cl 4.38, N 7.10.
[RuCl(η6-p-cymene)(HIm)2]BPh4 (17): This complex was prepared
following the method described above for 15 and 16 using HIm as
[RuCl(η6-p-cymene)(HRpz)2]BPh4 (15, 16) [R = H (15), 3-Me (16)]:
In a 25 mL three-necked round-bottomed flask were placed
RuCl2(CO)(η6-p-cymene) (0.10 g, 0.3 mmol), an excess of the ap-
propriate HRpz (0.9 mmol), an excess of NaBPh4 (0.6 mmol,
0.205 g), ethanol (3 mL) and dichloromethane (5 mL). The re-
sulting solution was stirred for 20 h and then the solvent was re-
moved under reduced pressure. The oil obtained was triturated with
ethanol (2 mL) until a yellow solid separated, which was collected
by filtration and crystallised from dichloromethane and ethanol;
yield 164 mg (71%) for 15, 164 mg (70%) for 16.
a reagent; yield 155 mg (67%). IR (KBr pellet): ν
= 3304 (m,
˜
NH
br) cm–1. 1H NMR (CD2Cl2, 25 °C): δ = 8.92 (br. s, 2 H, NH),
7.34–6.88 (m, 20 H, BPh4), 7.08, 6.91, 6.68 (d, 6 H, CH HIm), 5.52,
5.23 (d, 4 H, Ph p-cym), 2.56 (m, 1 H, CH iPr), 1.78 (s, 3 H, CH3
p-cym), 1.14 (d, 6 H, CH3 iPr) ppm. 13C{1H} NMR (CD2Cl2,
25 °C): δ = 165–122 (m, Ph), 138.39, 130.10, 118.15 (s, CH HIm),
Table 3. Crystal data and structure refinement.
1b
11a
15
Empirical formula
Formula weight
Temperature
Wavelength
Crystal system
Space group
C94H106B2Cl2N4O4P2Ru2
1712.43
293(2) K
0.71073 Å
monoclinic
Pc
C46H56BN4O3PRu
855.80
293(2) K
0.71073 Å
orthorhombic
P212121
C40H42BClN4Ru
726.11
293(2) K
0.71073 Å
triclinic
¯
P1
Unit cell dimensions
a = 13.3727(16) Å
b = 9.4736(12) Å
c = 35.117(4) Å
α = 90°
a = 10.840(2) Å
b = 20.077(4) Å
c = 20.383(5) Å
α = 90°
a = 9.9659(13) Å
b = 12.3667(17) Å
c = 16.080(2) Å
α = 104.137(2)°
β = 95.495(2)°
γ = 106.743(3)°
1810.6(4) Å3
2
β = 102.330(4)°
γ = 90°
β = 90°
γ = 90°
Volume
Z
Density (calculated)
Absorption coefficient
F(000)
4346.3(9) Å3
2
4436.4(17) Å3
4
1.309 Mg/m3
0.498 mm–1
1784
1.281 Mg/m3
0.432 mm–1
1.332 Mg/m3
0.540 mm–1
1792
752
Crystal size
0.32ϫ0.26ϫ0.21 mm
0.37ϫ0.15ϫ0.12 mm
1.42 to 25.05°.
–9 Յ h Յ 12
–23 Յ k Յ 23
–24 Յ l Յ 23
19736
0.34ϫ0.17ϫ0.10 mm
1.33 to 25.04°.
–11 Յ h Յ 11
–14 Յ k Յ 14
–19 Յ l Յ 19
13641
Theta range for data collection 1.56 to 25.05°.
Index ranges
–14 Յ h Յ 15
–11 Յ k Յ 11
–41 Յ l Յ 37
22119
Reflections collected
Independent reflections
Reflections observed (Ͼ2σ)
Data completeness
Absorption correction
Max. and min. transmission
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [IϾ2σ(I)]
R indices (all data)
Absolute structure parameter
Largest diff. peak and hole
12129 [R(int) = 0.0895]
6457
0.994
7235 [R(int) = 0.1121]
4023
0.968
semiempirical from equivalents
1.0000 and 0.6393
full-matrix least-squares on F2
7235/0/511
6313 [R(int) = 0.0475]
4356
0.987
1.000 and 0.712
1.000 and 0.928
12129/2/1001
1.013
6313/0/435
1.057
R1 = 0.0435 wR2 = 0.0956
R1 = 0.0801 wR2 = 0.1114
0.878
R1 = 0.0615 wR2 = 0.1175
R1 = 0.1534 wR2 = 0.1552
0.02(4)
R1 = 0.0580 wR2 = 0.1078
R1 = 0.1156 wR2 = 0.1261
–0.08(5)
0.524 and –0.799 eÅ–3
0.359 and –0.519 eÅ–3
0.546 and –0.365 eÅ–3
518
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Eur. J. Inorg. Chem. 2011, 510–520

Ru and Os Half-Sandwich Complexes
[4]
a) M. A. Esteruelas, F. J. Lahoz, J. A. Lopez, L. A. Oro, C.
Schlünken, C. Valero, H. Werner, Organometallics 1992, 11,
2034–3043; b) M. L. Christ, S. Sabo-Etienne, G. Chung, B.
Chaudret, Inorg. Chem. 1994, 33, 5316–5319; c) M. A. Es-
teruelas, F. J. Lahoz, A. M. Lopez, E. Oñate, L. A. Oro, N.
Ruiz, E. Sola, J. I. Tolosa, Inorg. Chem. 1996, 35, 7811–7817; d)
M. A. Esteruelas, M. Olivan, E. Oñate, N. Ruiz, M. A. Tajada,
Organometallics 1999, 18, 2953–2960.
a) J. Klingele, S. Dechert, F. Meyer, Coord. Chem. Rev. 2009,
253, 2698–2741; b) I. N. Stepanenko, B. Cebrián-Losantos,
V. B. Arion, A. A. Krokhin, A. A. Nazarov, B. K. Keppler, Eur.
J. Inorg. Chem. 2007, 400–411; c) H. Jude, F. N. Rein, W. Chen,
B. L. Scott, D. M. Dattelbaum, R. C. Rocha, Eur. J. Inorg.
Chem. 2009, 683–690; d) J. Pérez, L. Riera, Eur. J. Inorg. Chem.
2009, 4913–4925.
a) M. A. Bennett, Coord. Chem. Rev. 1997, 166, 225–254; b)
M. A. Bennett, Comprehensive Organometallic Chemistry II
(Eds.: E. W. Abel, F. G. A. Stone, G. Wilkinson), Elsevier, Ox-
ford, 1995, vol. 7, pp. 549–602; c) H. Le Bozec, D. Touchard,
P. H. Dixneuf, Adv. Organomet. Chem. 1989, 29, 163–247; d) T.
Naota, H. Takaya, S.-I. Murahashi, Chem. Rev. 1998, 98,
2599–2660.
a) F. Marchetti, C. Pettinari, R. Pettinari, A. Cerquetella, C.
Di Nicola, A. Macchioni, D. Zuccaccia, M. Monari, F. Picci-
nelli, Inorg. Chem. 2008, 47, 11593–11603; b) A. Prades, M.
Viciano, M. Sanau, E. Peris, Organometallics 2008, 27, 4254–
4259; c) R. Castarlenas, M. A. Esteruelas, E. Oñate, Organome-
tallics 2008, 27, 3240–3247; d) A. B. Chaplin, C. Fellay, G. Lau-
renczy, P. J. Dyson, Organometallics 2007, 26, 586–593; e) J.
Wolf, K. Thommes, O. Briel, R. Scopelliti, K. Severin, Organo-
metallics 2008, 27, 4464–4474; f) J. Vergnaud, M. Grellier, G.
Bouhadir, L. Vendier, S. Sabo-Etienne, D. Bourissou, Organo-
metallics 2008, 27, 1140–1146.
a) R. Schuecker, R. D. John, M. A. Jakupec, V. B. Arion, B. K.
Keppler, Organometallics 2008, 27, 6587–6595; b) P. Govindas-
wamy, Y. A. Mozharivskyj, M. R. Kollipara, J. Organomet.
Chem. 2004, 689, 3265–3274.
a) T. Bugarcic, A. Habtemariam, J. Stepankova, P. Heringova,
J. Kasparkova, R. J. Deeth, R. D. L. Johnstone, A. Prescimone,
A. Parkin, S. Parsons, V. Brabec, P. J. Sadler, Inorg. Chem.
2008, 47, 11470–11486; b) W. H. Ang, P. J. Dyson, Eur. J. Inorg.
Chem. 2006, 4003–4018; c) C. A. Vock, C. Scolaro, A. D. Phil-
lips, R. Scopelliti, G. Sava, P. J. Dyson, J. Med. Chem. 2006,
49, 5552–5561.
a) D. Carmona, J. Ferrer, J. M. Arilla, J. Reyes, F. J. Lahoz, S.
Elipe, F. J. Modrego, L. A. Oro, Organometallics 2000, 19, 798–
808; b) L. A. Oro, D. Carmona, M. P. Garcia, F. J. Lahoz, J.
Reyes, F. H. Cano, C. Foces-Foces, J. Organomet. Chem. 1985,
296, C43; c) D. Carmona, J. Ferrer, I. M. Marzial, L. A. Oro,
S. Trofimenko, Gazz. Chim. Ital. 1994, 124, 35–42; d) D. Car-
mona, J. Ferrer, L. A. Oro, M. C. Apreda, C. Foces-Foces,
F. H. Cano, J. Elguero, M. L. Jimeno, J. Chem. Soc., Dalton
Trans. 1990, 1463–1476.
a) G. Albertin, S. Antoniutti, F. Callegaro, J. Castro, Organo-
metallics 2009, 28, 4475–4479; b) G. Albertin, S. Antoniutti, J.
Castro, Eur. J. Inorg. Chem. 2009, 5352–5357; c) G. Albertin,
S. Antoniutti, J. Castro, J. Organomet. Chem. 2010, 695, 574–
579.
103.53 (s, C1 p-cym), 100.28 (s, C4 p-cym), 86.26 (s, C2 p-cym),
81.68 (s, C3 p-cym), 31.19 (s, CH iPr), 22.36 (s, CH3 iPr), 18.28
(s, CH3 p-cym) ppm. ΛM = 52.6 Ω–1 mol–1 cm2. C40H42BClN4Ru
(726.12): calcd. C 66.16, H 5.83, Cl 4.88, N 7.72; found C 66.03,
H 5.75, Cl 4.75, N 7.59.
X-ray Crystallography: Crystallographic data were collected with a
Bruker Smart 1000 CCD diffractometer at CACTI (Universidade
de Vigo) with graphite monochromated Mo-Kα radiation (λ =
0.71073 Å) and were corrected for Lorentz and polarisation effects.
SMART software[29] was used for collection of data frames, in-
dexing of reflections and determination of lattice parameters,
SAINT[30] for integration of intensity of reflections and scaling,
and SADABS[31] for empirical absorption correction. In the case
of 1b, study of the systematic absence prompted us to examine the
noncentrosymmetric Pc space group and the related centrosymmet-
ric P2/c space group. The Pc space group was finally used as well
as two whole unit formulae in the asymmetric unit, due to small
differences in the two molecules, and all attempts to find any sym-
metry relation to merge the two molecules was unsuccessful. For
[5]
[6]
[7]
¯
orthorhombic 11a and triclinic 15, the P1 or P212121 space groups
were chosen, respectively. Structures were solved and refined with
the Oscail program[32] by direct methods (1b and 11a) or by Pat-
terson methods (15) and refined by a full-matrix least-squares
method based on F2.[33] Non-hydrogen atoms were refined with an-
isotropic displacement parameters. Hydrogen atoms were included
in idealised positions and refined with isotropic displacement pa-
rameters but, in the case of 15, hydrogen atoms on the NH groups
were found in the electron density map and refined with isotropic
displacement parameters. In the case of 11a, the presence of a
HRpz ligand and a pz ligand in the coordination sphere made it
difficult to decide which was the anionic and which the neutral
ligand, because C–C or C–N bond parameters did not differ suffi-
ciently to allow a decision to be taken. However, refinement of the
occupancy factor of the two hypothesised positions provided an
answer, and the hydrogen atom labelled as H(2N) was refined with
isotropic displacement parameters. Details of crystal data and
structural refinement are given in Table 3.
[8]
[9]
CCDC-785127 (for 1b), -785128 (for 11a), -785129 (for 15) contain
the supplementary crystallographic data for this paper. These data
can be obtained free of charge from The Cambridge Crystallo-
graphic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
[10]
[11]
Acknowledgments
The financial support by the Ministero dell’Istruzione, dell’Univer-
sità e della Ricerca (MIUR), (Programmi di Ricerca Scientifica di
Rilevante Interesse Nazionale, PRIN 2007) is gratefully acknowl-
edged. We thank Mrs. Daniela Baldan, from the Università Ca’
Foscari Venezia for technical assistance.
[12]
[13]
[14]
W. J. Geary, Coord. Chem. Rev. 1971, 7, 81–112.
[1] a) S. Trofimenko, Chem. Rev. 1972, 72, 497–509; b) S. Trofi-
menko, Prog. Inorg. Chem. 1986, 34, 115–210.
L. J. Farrugia, J. Appl. Crystallogr. 1997, 30, 565–566.
a) G. A. Ardizzoia, G. La Monica, A. Maspero, M. Moret, N.
Masciocchi, Eur. J. Inorg. Chem. 1998, 1503–1512; b) G. A. Ar-
dizzoia, G. La Monica, S. Cenini, M. Moret, N. Masciocchi, J.
Chem. Soc., Dalton Trans. 1996, 1352–1357.
a) D. Carmona, L. A. Oro, M. P. Lamata, J. Elguero, M. d. C.
Apreda, C. Foces-Foces, F. H. Cano, Angew. Chem. Int. Ed.
Engl. 1986, 25, 1114–1115; b) A. Paulo, A. Domingos, I. San-
tos, Inorg. Chem. 1996, 35, 1798–1807.
[2] a) A. P. Sadimenko, S. S. Basson, Coord. Chem. Rev. 1996, 147,
247–297; b) G. La Monica, G. A. Ardizzoia, Prog. Inorg. Chem.
1997, 46, 151–238; c) R. Mukherjee, Coord. Chem. Rev. 2000,
203, 151–218; d) F. Meyer, Eur. J. Inorg. Chem. 2006, 3789–
3800; e) M. A. Halcrow, Dalton Trans. 2009, 2059–2073.
[3] a) T. Beringhelli, G. D’Alfonso, M. Panigati, F. Porta, P. Mer-
candelli, M. Moret, A. Sironi, Organometallics 1998, 17, 3282–
3292; b) T. Beringhelli, G. DЈAlfonso, M. Panigati, P. Mercand-
elli, A. Sironi, Chem. Eur. J. 2002, 8, 5340–5350, and references
therein.
[15]
[16]
D. Röttgen, G. Erker, M. Grehl, R. Fröhlich, Organometallics
1994, 13, 3897–3902.
Eur. J. Inorg. Chem. 2011, 510–520
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
519

G. Albertin, S. Antoniutti, J. Castro, S. García-Fontán
FULL PAPER
[17] a) G. Albertin, S. Antoniutti, A. Bacchi, G. Pelizzi, M. Tollon,
J. Organomet. Chem. 2005, 690, 4573–4582; b) G. Albertin, S.
Antoniutti, J. Castro, S. Garcia-Fontán, E. Gurabardhi, J. Or-
ganomet. Chem. 2006, 691, 1012–1024.
[18] a) C. A. Tolman, Chem. Rev. 1977, 77, 313–348; b) D. White,
B. C. Taverner, N. J. Coville, P. W. Wade, J. Organomet. Chem.
1995, 495, 41–51; c) H. Clavier, S. P. Nolan, Chem. Commun.
2010, 46, 841–861.
[19] J. G. Małecki, J. O. Dzigielewski, R. Kruszynski, T. J. Bartczak,
Inorg. Chem. Commun. 2003, 6, 721–724.
[20] Search in the CSD database, CSD version 5.31 (updated in
November 2009): Ru–N bond lengths of 25 complexes contain-
ing monodentate pyrazole ligand bonded to a RuII atom range
from 2.066 to 2.177 Å (average 2.114 Å).
[21] D. S. Bohle, E. S. Sagan, Eur. J. Inorg. Chem. 2000, 1609–1616.
[22] B. G. Harvey, Y. Shi, B. K. Peterson, A. M. Arif, R. D. Ernst,
Inorg. Chim. Acta 2006, 359, 839–845.
[23] J. G. Małecki, Polyhedron 2010, 29, 1237–1242.
[24] a) M. M. T. Khan, P. S. Roy, K. Venkatasubramanian, N. H.
Khan, Inorg. Chim. Acta 1990, 176, 49–55; b) A. M. Kirillov,
M. Haukka, M. F. C. Guedes da Silva, A. J. L. Pombeiro, Eur.
J. Inorg. Chem. 2007, 1556–1565.
[25]
R. Tribó, J. Pons, R. Yáñez, J. F. Piniella, A. Alvarez-Larena,
J. Ros, Inorg. Chem. Commun. 2000, 3, 545–549.
R. Rabinowitz, J. Pellon, J. Org. Chem. 1961, 26, 4623–4626.
G. Balacco, J. Chem. Inf. Comput. Sci. 1994, 34, 1235–1241;
http://www.inmr.net/.
a) G. Albertin, S. Antoniutti, J. Castro, S. Paganelli, J. Or-
ganomet. Chem. 2010, 695, 2142–2152; b) E. Hodson, S. J.
Simpson, Polyhedron 2004, 23, 2695–2707.
SMART, version 5.054, Instrument control and data collection
software, Bruker Analytical X-ray Systems Inc., Madison, Wis-
consin, USA, 1997.
SAINT, version 6.01, Data Integration software package,
Bruker Analytical X-ray Systems Inc., Madison, Wisconsin,
USA, 1997.
[26]
[27]
[28]
[29]
[30]
[31]
G. M. Sheldrick, SADABS. A Computer Program for Absorp-
tion Corrections, University of Göttingen, Germany, 1996.
P. McArdle, J. Appl. Crystallogr. 1995, 28, 65–65.
G. M. Sheldrick, Acta Crystallogr., Sect. A 2008, 64, 112–122.
Received: July 23, 2010
[32]
[33]
Published Online: December 22, 2010
520
www.eurjic.org
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2011, 510–520