Reactivity towards acidic protic ligands of cyclopalladated di-μ-hydroxo complexes

Article abstract of DOI:10.1002/ejic.200800445

The dinuclear hydroxo complexes [{Pd(μ-OH)(C∧N)}₂] [C∧N = 2-(2-pyridyl)phenyl (Phpy) (I), 7,8-benzoquinolyl (Bzq) (II) and 2-(2-oxazolinyl)phenyl (Phox) (III)] react in a 1:2 molar ratio with a wide variety of protic electrophiles H(L∧L) bearing different sets of donor atoms (L∧L = O∧O or O∧N) to give the mononuclear neutral palladium(II) derivatives with the general formula [Pd(L∧L)(C∧N)] [O∧O = salicylaldehydate (sal) (1), acetylacetonate (acac) (2) and benzoylacetonate (bzac) (3); O∧N = N-phenylsalicylaldiminate (N-Phsal) (4), N-p-chlorophenylsalicylaldiminate (N-pClPhsal) (5), 2-pyrrolecarbaldeydate (2-pcal) (6), 8-hydroxyquinolinate (oxin) (7)]. Structural characterisation of complexes I1, I3, I6, II4, II5 and III5 by X-ray diffraction confirmed the proposed formulae. Dinuclear complexes [{Pd(μ-N∧S)(C∧N)}₂] [N∧S = 2-pyridinethiolate (spy)] (8) were obtained when treating complexes I-III with 2-mercaptopyridine in the same molar ratio. A related process takes place when the three precursors react with ammonium O,O′- diethyldithiophosphate under mild conditions and complexes [Pd{S(S)P(OEt) ₂}(C∧N)] (I9-III9) are obtained. Deprotonation of the secondary amine Et₂NH by complexes I-III in the presence of carbon disulfide leads to the corresponding dithiocarbamate complexes [Pd(S₂CNEt ₂)(C∧N)] (I10-III10). The new complexes were characterised by analytical and spectroscopic techniques (IR and ¹H NMR). Wiley-VCH Verlag GmbH & Co. KGaA, 2008.

Full text of DOI:10.1002/ejic.200800445

FULL PAPER
DOI: 10.1002/ejic.200800445
Reactivity Towards Acidic Protic Ligands of Cyclopalladated Di-µ-hydroxo
Complexes
José Luis Serrano,*[a] Luis García,[a] José Pérez,[a] Eduardo Pérez,[a] Joaquín García,[b]
Gregorio Sánchez,[b] Gregorio López,[b] and Malva Liu[c]
Keywords: Cyclometalated palladium(II) complexes / Hydroxo complexes / X-ray studies
∧
∧
The dinuclear hydroxo complexes [{Pd(µ-OH)(C N)}2] [C N
= 2-(2-pyridyl)phenyl (Phpy) (I), 7,8-benzoquinolyl (Bzq) (II)
and 2-(2-oxazolinyl)phenyl (Phox) (III)] react in a 1:2 molar
idinethiolate (spy)] (8) were obtained when treating com-
plexes I–III with 2-mercaptopyridine in the same molar ratio.
A related process takes place when the three precursors re-
act with ammonium O,OЈ-diethyldithiophosphate under mild
∧
ratio with a wide variety of protic electrophiles H(L L) bear-
∧
∧
∧
∧
ing different sets of donor atoms (L L = O O or O N) to give
the mononuclear neutral palladium(II) derivatives with the
conditions and complexes [Pd{S(S)P(OEt)2}(C N)] (I9–III9)
are obtained. Deprotonation of the secondary amine Et2NH
by complexes I–III in the presence of carbon disulfide
leads to the corresponding dithiocarbamate complexes
∧
∧
∧
general formula [Pd(L L)(C N)] [O O = salicylaldehydate
(sal) (1), acetylacetonate (acac) (2) and benzoylacetonate
(bzac) (3); O N = N-phenylsalicylaldiminate (N-Phsal) (4), N-
∧
∧
[Pd(S2CNEt2)(C N)] (I10–III10). The new complexes were
p-chlorophenylsalicylaldiminate (N-pClPhsal) (5), 2-pyrrole-
carbaldeydate (2-pcal) (6), 8-hydroxyquinolinate (oxin) (7)].
Structural characterisation of complexes I1, I3, I6, II4, II5 and
III5 by X-ray diffraction confirmed the proposed formulae.
characterised by analytical and spectroscopic techniques (IR
and H NMR).
1
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2008)
∧
∧
∧
Dinuclear complexes [{Pd(µ-N S)(C N)}2] [N S = 2-pyr-
Introduction
With regard to the cyclopalladated systems whose reac-
tivity we present here, the related acetate- or halide-bridged
dimers have been extensively employed as convenient pre-
cursors of mononuclear and dinuclear cyclometalates.[9,10]
Since 1970 to date several reviews have been dedicated to
different aspects of their chemistry such as synthesis and
structural characterization, their applications in organic
synthesis, organometallic catalysis, their presence in medici-
nal and biological chemistry or their use as chiral auxilia-
ries, mesogenic and luminescent agents.[11] In their excellent
review, Ghedini and coworkers[11a] have pointed out the re-
lationship between molecular geometries, types of ligands
and important physical properties of dinuclear and mono-
In addition to their interest relating to applied fields such
as antitumour activity[1] or catalytic processes,[2] the syn-
thetic value of palladium(II) and platinum(II) di-µ-hydroxo
complexes is a subject of continuous study.[3] For example,
Sharp et al.[4] and later others[5] have employed several such
complexes as precursors in the preparation of scarce oxo
and imido derivatives that are also relevant to C–O and C–
N bond-forming reactions in catalytic processes. The reac-
tivity towards protic substrates of dinuclear compounds
[Pd(µ-OH)Ln]2 (Ln = orthometalated imine-based ligands)
provides a general route to obtaining dinuclear complexes
with double and mixed bridges that have shown liquid crys-
tal behaviour.[6] In this sense, during the last years we have
also been developing the usefulness of dinuclear hydroxo
complexes of palladium, some of them with a cyclomet-
alated backbone,[7] in the preparation of a wide variation of
new compounds by means of a simple acid–base reaction.[8]
∧
∧
nuclear cyclometalated derivatives containing O O, N N
∧
or O N complementary ligands. Thus, the authors have
studied the effects exerted by different bridging groups on
the spectroscopic and liquid-crystalline properties of com-
∧
plexes of the type [{Pd(µ-X)(C N)}2] (X = halide, azido,
thiocyanate, oxalate or acetate),[12]or the presence of an
asymmetric coordination around the palladium atom as a
key aspect for photophysical properties, which is well exem-
plified by complexes [Pd(oxin-R)(Phpy)] that emit in solu-
tion at room temperature.[13] Cyclopalladated acetylace-
tonate complexes have also been thoroughly studied, show-
ing again the importance of the orthometalated backbone
and the substituents on the acac moiety in the fine tuning of
properties.[14] As a whole these results suggest that related
[a] Departamento de Ingeniería Minera, Geológica
y Car-
tográfica.Universidad Politécnica de Cartagena Área de Quím-
ica Inorgánica,
30203 Cartagena, Spain
E-mail: jose.serrano@upct.es
[b] Departamento de Química Inorgánica, Universidad de Murcia,
30071 Murcia, Spain
E-mail: gsg@um.es
[c] Departamento de Termodinámica, Universidad de Valencia,
46100 Burjassot (Valencia), Spain
E-mail: liu@uv.es
Eur. J. Inorg. Chem. 2008, 4797–4806
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4797

J. L. Serrano et al.
FULL PAPER
complexes can be candidates for the above-mentioned prac- ligands labelled with their abbreviations are shown in
tical applications. Scheme 1. The reactions explored in this paper and the spe-
Apart from their intrinsic interest, the hydroxo com- cific conditions followed for each of them are collected in
plexes of palladium, whose reactivity we present here, can the Experimental Section.
offer a convenient and faster route in the preparation of
compounds that may not be accessible using classical halide H(L L) to give mono- or dinuclear species depending on
The hydroxo complexes react with weak protic acids
∧
–
∧
or acetate precursors. In this paper we explore the reactivity whether the deprotonated acid (L L) is exo- or endo-bi-
∧
∧
of complexes [{Pd(µ-OH)(C N)}2] [C N = 2-(2-pyridyl)- dentate. These reactions can be viewed as an initial proton
–
∧
phenyl (Phpy) (I), 7,8-benzoquinolyl (Bzq) (II) and 2-(2- abstraction by the complexes I–III that provides (L L) and
oxazolinyl)phenyl (Phox) (III)] towards several protic elec- the metal substrate, subsequently trapped by the anion to
trophiles and describe other related reactions, like those form the new complexes of the general formula
∧
∧
∧
∧
with amines in the presence of carbon disulfide.
[Pd(L L)(C N)] (I–III/1–7) or [{Pd(µ-N S)(C N)}2] (I8–
III8). It is worth noting that the syntheses of acac com-
plexes I2, II2 and III2 has previously been reported by tre-
Results and Discussion
∧
ating [{Pd(µ-OOCMe)(C N)}2] with an excess amount of
The cyclometalated precursors [{Pd(µ-OH)(C N)}2] K(acac), prepared in advance.[14,15] The complex [Pd-
∧
[C N = (Phpy) (I), (Bzq) (II) and (Phox) (III)] were conve- (oxin)(Phpy)] (I7), which is a good emitter in solution,[13]
∧
niently prepared by the treatment of the corresponding ace- has also been prepared in a similar manner. Longer reac-
tate-bridged complexes with NBu4OH in acetone. The tion times (5–12 h) and successive filtration and extraction
drawings of the dinuclear precursor together with the acidic steps in the reported procedure, in comparison with the
Scheme 1. Precursors and acidic ligands under study.
4798
www.eurjic.org
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 4797–4806

Cyclopalladated Di-µ-hydroxo Complexes
straightforward route that we present here, make our hy- ylacetonate derivatives with the 1H NMR spectra consisting
droxo complexes appropriate precursors in the preparation of a mixture of the two isomers in a variable ratio depend-
of such complexes, and allow one to envisage their general ent on the cyclometalated backbone, the solvent and the
usefulness when treating them with other substrates. The time since the preparation. In fresh CDCl3 solution spectra
considerable nucleophilicity of the bridging OH groups of showed a mixture with a predominant isomer with low-field
the three precursors also makes them reactive towards am- bzac signals (II/III ≈ 1.8 for I3, 3.0 for II3 and 1.4 for III3;
monium O,OЈ-diethyldithiophosphate, yielding complexes average integrated peak ratio II/III taken from the corre-
I9–III9 with the concomitant release of NH3 and H2O. The sponding two methine or methyl signals), and after three
preparation of the dithiocarbamate complexes I10–III10 hours the ratio in all cases changed to II/III ≈ 1. In deuter-
should involve a first step of amine deprotonation, followed ated acetone as the solvent this proportion was immediately
by nucleophilic attack of Et2N– to carbon disulfide to form reached and did not change with time. We were able to ob-
the dithiocarbamate anion. It was impossible to prepare tain crystals of I3 from CHCl3/hexane suitable for an X-ray
complex III7 by this route. In all attempts made we have diffraction study that revealed the presence of the isomer
spectroscopic evidence of the bis(8-quinolinato)palladi- with the Ph-carbonylic oxygen placed trans to the ortho-
um(II) complex instead of the expected [Pd(oxin)(Phox)] metalated carbon atom. An unequivocal explanation for a
complex.
specific isomer choice in the solid state is difficult to find,
The new palladium complexes are air-stable and their IR and it has been studied in the case of Rh(I) complexes with
spectra show strong bands around 1600 cm–1, characteristic β-diketones.[17]
of the corresponding cyclometalated backbone, and in
With regard to the rest of the complexes with a 2-(2-
some cases partly overlapped by the absorptions that are oxazolinyl)phenyl backbone (III), their spectra show just
attributed to the incoming ligands (see Exp. Section). The two triplets for the NCH2 and OCH2 protons in the 3.70–
absence of relevant bands in the region 3000–3500 cm–1 can 4.80 ppm region, except for complex [{Pd(µ-Spy)(Phox)}2]
be interpreted as both deprotonation of acidic ligands and (III8) in which a set of three unresolved multiplets (ratio
complete reaction of the hydroxo-palladium precursors. 1:2:1) is observed. This observation supports the proposed
This fact was also supported by the 1H NMR spectra, coordination, as this behaviour has been reported for the
1
where no high-field resonances are found. The H NMR related dinuclear complexes [{Pd(µ-X)(Phox)}2] (X = ace-
–
tate[15] or imidate[18]) in which each of two methylene pro-
∧
spectra also show the corresponding signals of the (L L)
ligands, frequently overlapped in the aromatic region with tons of the oxazoline ring are nonequivalent as a conse-
those of the cyclometalated backbone (especially complexes quence of the open-book structure of the complexes. The
I and II). In principle, new complexes containing the li- 31P NMR spectra of complexes I9–III9 show a single reso-
gands 1, 3–7 can exist as two isomers depending on the nance for the coordinated dithiophosphate ligands at the
∧
∧
relative positions of the C N/O O (complexes labelled 1 usual range.
∧
∧
and 3) or C N/O N (complexes 4–7) chelating systems. In
The mono- or dinuclearity of the new complexes is also
the latter, the presence of only one isomer was observed by supported by FAB mass spectrometry and the positive
1H NMR spectroscopy. The determination of the molecular FAB-MS data of the complexes with the m/z values for the
structures of I6, II4, II5 and III5 by X-ray analysis revealed observed fragments (M+ and M+ – L L as a common
∧
a N,N-trans arrangement in complexes I6, II4 and II5, while pattern) are collected in the Experimental Section. The
a N,N-cis disposition was found in the 2-(2-oxazolinyl)- abundance of the signals around the parent ion is consistent
phenyl derivative III5, suggesting a dependence on the spe- in all cases with the natural isotopic abundances.
cific cyclometalated system and that those isomers could
As mentioned above, the mononuclear nature of 2-(2-
also be predominant in solution. This dependence and the pyridyl)phenyl derivatives I1, I3 and I6 that contain chelat-
∧
∧
∧
∧
prevalence of the N,N-trans arrangement in C N/O N sys- ing O O and O N donor ligands has also been confirmed
∧
tems, where O N is either the related Schiff base or the 8- by single-crystal X-ray analysis. The ORTEP drawings of
hydroxyquinoline ligands, are also noted after a survey of the three complexes are shown in Figure 1, Figure 2 and
the Cambridge Structural Database (CSD) v. 5.29 (updated Figure 3, while the relevant bond lengths and angles are
1
to November 2007). On the other hand the H NMR spec- reported in Table 1.
tra of complexes I1–III1 with salicylaldehydate as the co-
With regard to the salicylaldehydate complex I1, it has
ligand showed a mixture in solution with an isomer ratio previously been reported for related complexes that an
of ca. 5:1 that did not change with time or the solvent used acac-type delocalization contributes to the overall structure,
(deuterated chloroform or acetone). A crystal structure de- reducing the importance of delocalization within the aro-
termination of I1 shows that the carbonylic oxygen is matic ring.[16] This also applies for I1 on the basis of quite
placed trans to the orthometalated carbon atom. This dis- close C12–C13 and C13–C18 distances [1.424(5) and
position has also been found in related complexes with a 1.439(5) Å], despite the fact that there is an aromatic and a
[16]
∧
C P backbone,
for which the authors identified this single bond in the parent ligand, and also the little differ-
complex as the major isomer in solution on the basis of ence between the C–O bond lengths (see Table 1). The unit
steric requirements of substituents on the carbonylic carbon cell of complex I1 contains two molecules. The coordina-
and the ability of the oxygen atoms to participate in hydro- tion around the Pd atoms based on measures of torsion
gen bonding. A different behaviour was displayed by benzo- angles is almost planar with a slight square-pyramidal dis-
Eur. J. Inorg. Chem. 2008, 4797–4806
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4799

J. L. Serrano et al.
FULL PAPER
Figure 1. ORTEP diagram of complex I1 with the atom numbering
scheme. Thermal ellipsoids are drawn at the 50% probability level.
Figure 3. An ORTEP representation of I6. Thermal ellipsoids are
drawn at the 50% probability.
tions [this method assigns the following probabilities for
conformations when a standard deviation of σ = 10 is al-
lowed: half-chair (HC) = 0.515; envelope (E) = 0.485 and
HC = 0.514; E = 0.486, respectively]. The six-membered
rings Pd1–O1–C18–C13–C12–O2 and Pd2–O4–C30–C31–
C36–O3 are also nearly planar [screw-boat (SB) = 0.998;
half-chair (HC) = 0.002 and SB = 0.999; HC = 0.001,
respectively]. The same preferences regarding ring confor-
mations were found for complex I3 (HC = 0.514; E = 0.486
and SB = 0.996; HC = 0.004). In this case the coordination
around the Pd atom is almost planar with slight tetrahedral
distortion (w1 = 1.11° and w2 = 1.97°). As mentioned above,
the isomer shown in Figure 2 with the relative C···O=C–Ph
and N···O=C–Me trans disposition is the one found in the
crystal. There is a notable difference between the distances
Pd1–O2 = 2.0950(13) Å and Pd1–O1 = 2.0101(13) Å due to
Figure 2. X-ray crystal structure of I3. Thermal ellipsoids are
drawn at the 50% probability. Hydrogen atoms are omitted for clar-
ity.
tortion[19] [w1(O1–C11–N1–Pd1) = 2.25° and w2(O2–N1– the larger trans influence exerted by the σ-bonded C atom.
C11–Pd1) = –0.24; w1(O3–C29–N2–Pd2) = 2.48° and Complex I6 (Figure 4) also contains two molecules in the
w2(O4–N2–C29–Pd2) = –0.01°]. The narrow N–Pd–C angle asymmetric unit. The coordination around the Pd atoms is
in the orthometalated moiety is similar to that found in almost planar with different distortions for each molecule:
other complexes containing the same ligand.[10a,10c]
w1 = 3.22° and w2 = –0.53° (square pyramidal) and w1 =
We have recently developed methods for the conforma- 1.43° and w2 = 1.81° (tetrahedral).
tional classification of eight-membered rings.[20] Using the
The four five-membered rings are almost planar with val-
so-called classification method, it can be concluded that the ues for the half-chair and envelope conformations that are
five-membered palladacycles Pd1–N1–C5–C6–C11 and similar to those found for complexes I1 and I3. This is the
Pd2–N2–C23–C24–C29 exhibit almost planar conforma- first X-ray crystal structure of a Pd complex containing
Table 1. Selected bond lengths [Å] and angles [°] for complexes I1, I3 and I6.
I1
I3
I6
Pd1–C11
Pd1–N1
Pd1–O1
Pd1–O2
C18–O1
C12–O2
1.965(3)
2.012(3)
2.018(2)
2.116(2)
1.293(4)
1.239(4)
Pd2–C29
Pd2–N2
Pd2–O3
Pd2–O4
C36–O3
C30–O4
1.957(3)
2.007(3)
2.009(2)
2.121(2)
1.303(4)
1.239(4)
Pd1–C11
Pd1–N1
Pd1–O1
Pd1–O2
C20–O1
C12–O2
1.9637(17)
2.0086(15)
2.0103(13)
2.0950(13)
1.274(2)
Pd1–C11
Pd1–N1
Pd1–N1
Pd1–O1
C12–O1
1.977(5)
2.013(3)
2.026(4)
2.170(3)
1.257(5)
Pd2–C27
Pd2–N3
Pd2–N4
Pd2–O2
C28–O2
1.980(4)
2.007(3)
2.036(3)
2.157(3)
1.253(5)
1.271(2)
C11–Pd1–N1 81.48(13)
C11–Pd1–O1 93.09(11)
C11–Pd1–O2 175.15(11) C29–Pd2–O4 175.72(12)
N1–Pd1–O1 173.69(10) N2–Pd2–O3 172.80(10)
C29–Pd2–N2 81.33(13)
C29–Pd2–O3 92.39(12)
C11–Pd1–N1 81.77(7)
C11–Pd1–O1 91.43(6)
C11–Pd1–O2 175.47(6)
N1–Pd1–O1 172.66(6)
N1–Pd1–O2 93.99(6)
C11–Pd1–N1 81.11(16)
C27–Pd2–N3 81.74(14)
C11–Pd1–N2 104.12(19) C27–Pd2–N4 103.90(14)
C11–Pd1–O1 175.97(16) C27–Pd2–O2 175.33(13)
N1–Pd1–N2 172.78(17) N3–Pd2–N4 173.68(13)
N1–Pd1–O1 94.90(12)
N2–Pd1–O1 79.81(15)
N1–Pd1–O2 93.68(10)
N2–Pd2–O4 94.39(10)
O3–Pd2–O4 91.88(9)
N3–Pd2–O2 94.05(12)
N4–Pd2–O2 80.40(12)
O1–Pd1–O2
91.72(9)
O1–Pd1–O2
92.88(5)
4800
www.eurjic.org
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 4797–4806

Cyclopalladated Di-µ-hydroxo Complexes
Figure 4. Molecular packing diagram of complex I6 and perspective view of the alignment of the two molecules.
simple chelating 2-pyrrolecarbaldehydate as searched from
the Cambridge Structural Database (CSD) v. 5.29 (updated
to November 2007).
The three 2-(2-pyridyl)phenyl derivatives display groups
of molecules stacked with plane-to-plane distances that are
compatible with a π interaction (3.3–3.8 Å).[21] In complex
I1 a stacking of three parallel molecules is observed in the
crystal structure with one of them placed between the other
two with different distances and overlapping degrees. Dis-
tances between planes (measured as the Pd plane) are 3.264
and 3.447 Å, while Pd–Pd distances are 3.350 and 6.175 Å.
In complexes I3 and I6 a stacking of parallel molecules
is also observed but is limited to two molecules (Pd···plane
distances are 3.437 and 3.323 Å, respectively). The crystal
Figure 5. ORTEP diagram of II4. Thermal ellipsoids are drawn at
the 50% probability level.
packing in I6 defines a narrow tunnel along the c direction
with a diameter of about 2.8 Å. It is worth noting the high
rate of alignment found in complex I6. A view of the crystal
packing is shown in Figure 4.
The structures of two 7,8-benzoquinolyl derivatives II4
(Figure 5) and II5 (Figure 6) have been confirmed by X-ray
diffraction analysis and selected bond lengths and angles
are collected in Table 2.
The coordination around the Pd atoms is almost planar
with slight tetrahedral distortion (w1 = –2.11°; w2 = –3.15°
and w1 = 1.88°; w2 = 1.95°). The cyclometalated five-mem-
bered rings Pd1–N1–C12–C13–C1 are almost planar with
values of probability for the conformations HC and E that
are close to the former complexes. With regard to the six-
membered rings Pd1–N2–C14–C15–C20–O1 in both II4
and II5, similar values of probability (SB = 0.991; HC =
0.006; E = 0.003 and SB = 0.987; HC = 0.007; E = 0.006)
to those of complex I1 with salicylaldehydate were found.
The chloride substituent in II5 does not seem to influence
the conformation of the ring, as it does not affect the N2–
C14 bond length, 1.306(3) and 1.304(2) Å in II4 and II5,
respectively. Both complexes II4 and II5 stack forming
chains (straight chains in the direction of the Pd atoms, see
Figure 6. Molecular structure of II5 with the labelling scheme.
Thermal ellipsoids are drawn at the 50% probability level. Hydro-
gen atoms have been omitted for clarity.
Figure 7), in which the planes defined by the metal and the Pd···plane distances of 6.220 and 3.249 Å in II4 and 6.351
orthometalated ligand are parallel, and show Pd···Pd and and 3.105 Å in II5, respectively.
Eur. J. Inorg. Chem. 2008, 4797–4806
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4801

J. L. Serrano et al.
FULL PAPER
Table 2. Selected distances [Å] and angles [°] of complexes II4, II5 and III5.[a]
II4
II5
III5
Pd1–C1
Pd1–N1
Pd1–N2
Pd1–O1
C1–Pd1–N1
C1–Pd1–N2
C1–Pd1–O1
N1–Pd1–N2
N1–Pd1–O1
N2–Pd1–O1
C14[a]–N2
C20[b]–O1
C24[c]–Cl1
2.026(5)
2.037(2)
2.031(2)
2.052(3)
82.04(12)
99.82(12)
168.74(14)
176.28(9)
87.57(9)
90.81(9)
1.306(3)
1.294(4)
2.0157(15)
2.0373(13)
2.0373(13)
2.0568(11)
82.06(6)
2.007(16)
2.036(13)
2.116(13)
2.009(11)
81.5(6)
178.4(6)
87.3(6)
99.9(5)
168.8(5)
91.3(5)
2.003(15)
2.083(14)
2.104(12)
2.027(11)
78.6(6)
176.6(5)
88.0(6)
102.5(5)
166.5(5)
91.0(5)
1.301(19)
1.28(2)
1.984(15)
2.032(14)
2.124(12)
2.004(10)
80.9(6)
178.6(6)
86.8(5)
100.5(5)
167.6(5)
91.8(5)
1.288(18)
1.298(17)
1.752(17)
99.93(6)
169.48(5)
176.50(5)
87.77(5)
90.36(5)
1.304(2)
1.2975(18)
1.7394(16)
1.33(2)
1.329(18)
1.770(16)
1.707(17)
[a] C10 in III5. [b] C16 in III5. [c] C20 in III5.
Figure 8. X-ray crystal structure of III5. Thermal ellipsoids are
drawn at the 50% probability. Hydrogens are omitted for clarity.
Conclusions
Figure 7. Packing diagram in II4.
We have employed di-µ-hydroxo complexes containing a
cyclometalated backbone as precursors in the preparation
of new compounds when ligand deprotonation was re-
The crystal structure of complex III5 (Figure 8) has also quired. Thus, stronger basic treatments were avoided re-
been solved by X-ray diffraction analysis. It displays three affirming the unique characteristics of such hydroxo com-
molecules in the asymmetric unit and its selected geometri- plexes as starting materials for simple acid–base reactions
cal features are given in Table 2. To date just three com- with protic electrophiles or related processes, like that of
plexes containing an orthopalladated 2-phenyl-2-oxazoline deprotonation of secondary amines in the presence of car-
ligand have been crystallographically characterised [search- bon disulfide to yield the corresponding dithiocarbamate
ing the Cambridge Structural Database (CSD) v. 5.29 up- complexes. Twenty nine palladium(II) complexes with 2-
dated to November 2007].[7b,15]
phenylpyridine, 7,8-benzoquinolyne or 2-phenyl-2-oxazol-
The overall coordination geometry about the palladium ine have been prepared in this manner and characterised by
atom is essentially square planar in the three molecules, spectroscopic techniques and single-crystal X-ray diffrac-
with a slight square pyramidal distortion for Pd(1) (w1 = tion analysis. We present the first X-ray crystal structure of
–0.53°; w2 = 0.16°) and Pd(3) (w1 = –0.28°; w2 = 1.18°) and a Pd complex containing simple chelating 2-pyrrolecarbal-
a tetrahedral distortion for Pd(2) (w1 = –2.07°; w2 = –1.14°). dehydate as searched from the Cambridge Structural Data-
The six-membered rings Pd–N–C–C–C–O in the three base (CSD) v. 5.29 (updated to November 2007). Prelimi-
molecules are also nearly planar (for example SB = 0.996; nary results show that most of the new complexes are good
HC = 0.004 for the ring Pd1–N2–C10–C11–C16–O1). The emitters in solution at room temperature. A comprehensive
cyclometalated five-membered rings Pd1–N1–C7–C6–C1 study exploiting their potential interest will be reported in
and equivalent are also almost planar.
due course.
4802
www.eurjic.org
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 4797–4806

Cyclopalladated Di-µ-hydroxo Complexes
1 H, Phpy), 7.56 (m, 2 H, Phpy), 7.36 (d, J = 5.4 Hz, 1 H, Phpy),
7.09 (m, 3 H, Phpy), 5.34 (s, 1 H, acac), 2.04 (s, 3 H, acac), 2.00
(s, 3 H, acac) ppm. FAB-MS (positive mode): m/z = 359 [Pd-
(acac)(Phpy)]+.
Experimental Section
General Remarks: C, H and N analyses were carried out with a
Carlo–Erba instrument. IR spectra were recorded with a Perkin–
Elmer spectrophotometer 16F PC FT-IR, using Nujol mulls be-
tween polyethylene sheets. NMR spectroscopic data (1H, 31P) were
recorded with Bruker Avance 300 or 400 spectrometers. Mass spec-
trometric analyses were performed with a Fisons VG Autospec
double-focusing spectrometer, operated in positive mode. Ions were
produced by fast atom bombardment (FAB) with a beam of 25-
KeV Cs atoms. The mass spectrometer was operated with an acce-
lerating voltage of 8 kV and a resolution of at least 1000.
[Pd(acac)(bzq)] (II2): Yield 0.075 g (59%). C18H15NO2Pd (383.7):
calcd. C 56.3, H 3.9, N 3.7; found C 56.3, H 3.8, N 3.6. IR (Nujol):
ν = 1618 (s), 1570 (vs), 1519 (vs) cm–1. 1H NMR (300 MHz,
˜
CDCl3): δ = 8.84 (d, J = 5.0 Hz, 1 H, Bzq), 8.16 (d, J = 8.1 Hz, 1
H, Bzq), 7.66 (m, 2 H, Bzq), 7.45 (m, 4 H, Bzq), 5.39 (s, 1 H, acac),
2.09 (s, 3 H, acac), 2.04 (s, 3 H, acac) ppm. FAB-MS (positive
mode): m/z = 383 [Pd(acac)(Bzq)]+.
[Pd(acac)(Phox)] (III2): Yield 0.078 g (60%). C14H15NO3Pd
∧
The cyclometalated precursors [{Pd(µ-OOCMe)(C N)}2][9h,15] and
(351.0): calcd. C 47.8, H 4.3, N 4.0; found C 47.9, H 4.2, N 4.0.
∧
[{Pd(µ-OH)(C N)}2][7c] were prepared as described in the litera-
ture. The commercially available chemicals were purchased from
Aldrich Chemical Co. and were used without further purification,
and all the solvents were dried by standard methods before use.
IR (Nujol): ν = 1634 (s), 1576 (vs), 1516 (vs) cm–1. 1H NMR
˜
(300 MHz, CDCl3): δ = 7.56 (d, J = 7.5 Hz, 1 H, Phox), 7.23 (m,
2 H, Phox), 7.05 (m, 1 H, Phox), 5.37 (s, 1 H, CH acac), 4.74 (t, J
= 9.6 Hz, 2 H, Phox, OCH2), 3.97 (t, J = 9.6 Hz, 2 H, Phox,
NCH2), 2.07 (s, 3 H, CH3 acac), 1.99 (s, 3 H, CH3 acac) ppm. FAB-
MS (positive mode): m/z = 351 [Pd(acac)(Phox)]+.
Synthesis
∧
∧
∧
Preparation of complexes [Pd(O O)(C N)] C N = (Phpy) (I),
(Bzq) (II) or (Phox) (III), O O = salicylaldehydate (sal) (I1–III1),
acetylacetonate (acac) (I2–III2) and benzoylacetonate (bzac) (I3–
∧
[Pd(bzac)(Phpy)] (I3): Yield 0.073 g (48%). C21H17NO2Pd (421.8):
calcd. C 59.8, H 4.1, N 3.2; found C 59.7, H 4.2, N 4.0. IR (Nujol):
∧
∧
∧
ν = 1606 (s), 1590 (vs), 1560 (vs) cm–1. 1H NMR (300 MHz,
III3); [Pd(O N)(C N)] O N = N-phenylsalicylaldiminate (N-
Phsal) (I4–III4), N-p-chlorophenylsalicylaldiminate (N-pClsal) (I5–
III5), 2-pyrrolecarbaldehydate (2-pcal) (I6–III6), 8-hydroxyquinol-
˜
CDCl3): δ = 8.89 (d, J = 5.4 Hz, 1 H, Phpy-isomer I), 8.81 (d, J =
5.4 Hz, 1 H, Phpy-isomer II), 7.98 (d, J = 7.6 Hz, 2 H, Ph-bzac
isomer I), 7.81 (d, J = 7.6 Hz, 2 H, Ph-bzac isomer II), 7.77 (m, 3
H, Phpy), 7.63 (m, 3 H, Phpy), 7.42 (m, 8 H, Phpy + bzac), 7.13
(m, 6 H, Phpy + bzac), 6.06 (s, 2 H, bzac), 2.25 (s, 3 H, bzac-isomer
I), 2.20 (s, 3 H, bzac-isomer II) ppm. FAB-MS (positive mode): m/z
= 421 [Pd(bzac)(Phpy)]+.
∧
∧
∧
inate (oxin) (I7–III7) and [{Pd(µ-N S)(C N)}2] N S = 2-pyridin-
thiolate (spy) (I8–III8).
The new complexes were obtained by treating a CH2Cl2 suspension
(20 mL) of the different precursors (I–III) (0.100 g) with the corre-
sponding protic ligand (HL L) (molar ratio 1:2). The suspension
∧
was stirred at room temperature for 30 min until a clear solution
was obtained and then it was concentrated under reduced pressure
until ca. one fifth of the initial volume. Slow addition of diethyl
ether caused the formation of the complexes, which were filtered
off, washed with diethyl ether and air-dried. The compounds were
recrystallised from dichloromethane/diethyl ether.
[Pd(bzac)(Bzq)] (II3): Yield 0.103 g (70%). C23H17NO2Pd (445.8):
calcd. C 62.0, H 3.8, N 3.1; found C 62.1, H 3.7, N 3.1. IR (Nujol):
ν = 1620 (s), 1590 (vs), 1562 (vs) cm–1. 1H NMR (300 MHz,
˜
CDCl3): δ = 8.95 (d, 1 H Bzq-isomer I, J = 5.2 Hz), 8.89 (d, 1 H,
Bzq-isomer II, J = 5.2 Hz), 8.20 (m, 2 H, Bzq), 8.03 (d, J = 7.6 Hz,
2 H, Ph-bzac isomer I), 7.97 (d, J = 7.6 Hz, 2 H, Ph-bzac isomer
II), 7.81 (m, 1 H, Bzq), 7.72 (m, 3 H, Bzq), 7.58–7.43 (m, 14 H, 8
Bzq + 6 bzac), 6.11 (s, 1 H, bzac isomer I), 6.09 (s, 1 H, bzac
isomer II), 2.30 (s, 3 H, bzac isomer I), 2.23 (s, 3 H, bzac isomer
II) ppm. FAB-MS (positive mode): m/z = 445 [Pd(bzac)(Bzq)]+.
[Pd(sal)(Phpy)] (I1): Yield 0.111 g (81%). C18H13NO2Pd (381.7):
calcd. C 56.6, H 3.4, N 3.7; found C 56.7, H 3.5, N 3.6. IR (Nujol):
ν = 1614 (vs), 1604 (s), 1578 (s), 1512 (vs) cm–1. 1H NMR
˜
(300 MHz, CDCl3): δ = 9.27 (s, 1 H, sal, CH=O), 8.76 (d, J =
5.4 Hz, 1 H, Phpy), 7.83 (m, 1 H, Phpy), 7.72 (d, J = 8.4 Hz, 1 H,
sal), 7.62 (d, J = 8.0 Hz, 1 H, Phpy), 7.41 (m, 3 H, Phpy), 7.19 (m,
3 H, 2 Phpy + 1 sal), 7.05 (d, J = 8.8 Hz, 1 H, sal), 6.60 (m, 1 H,
sal) ppm. FAB-MS (positive mode): m/z = 381 [Pd(sal)(Phpy)]+.
[Pd(bzac)(Phox)] (III3): Yield 0.084 g (55%). C19H17NO3Pd
(413.7): calcd. C 55.2, H 4.1, N 3.4; found C 55.3, H 4.2, N 3.4. IR
(Nujol): ν = 1631 (s), 1555 (s), 1518 (s) cm–1. 1H NMR (300 MHz,
˜
CDCl3): δ = 7.94 (d, J = 7.6 Hz, 2 H, Ph-bzac isomer I), 7.87 (d,
J = 8.0 Hz, 2 H, Ph-bzac isomer II), 7.70 (d, J = 7.6 Hz, 1 H,
Phox-isomer I), 7.61 (d, J = 7.6 Hz, 1 H, Phox-isomer II), 7.43 (m,
6 H, bzac), 7.27 (m, 4 H, Phox), 7.08 (m, 2 H, Phox), 6.06 (s, 1 H,
CH bzac-isomer I), 6.03 (s, 1 H, CH bzac-isomer II), 4.77 (m, 4 H,
Phox), 4.06 (m, 4 H, Phox), 2.22 (s, 3 H, CH3 bzac isomer I), 2.13
(s, 3 H, CH3 bzac isomer II) ppm. FAB-MS (positive mode): m/z
= 413 [Pd(bzac)(Phox)]+.
[Pd(sal)(Bzq)] (II1): Yield 0.102 g (76%). C20H13NO2Pd (405.7):
calcd. C 59.2, H 3.2, N 3.5; found C 59.3, H 3.3, N 3.4. IR (Nujol):
ν = 1619 (br), 1600 (s), 1516 (s) cm–1. 1H NMR (300 MHz, CDCl ):
˜
3
δ = 9.26 (s, 1 H, sal, CH=O), 8.88 (d, J = 5.1 Hz, 1 H, Bzq), 8.22
(d, J = 7.9 Hz, 1 H, Bzq), 7.75 (m, 2 H, sal + Bzq) 7.45 (m, 6 H,
5 Bzq + 1 sal), 7.11 (d, J = 8.6 Hz, 1 H, sal), 6.61 (m, 1 H, sal) ppm.
FAB-MS (positive mode): m/z = 405 [Pd(sal)(Bzq)]+.
[Pd(N-Phsal)(Phpy)] (I4): Yield 0.132 g (80%). C24H18N2OPd
[Pd(sal)(Phox)] (III1): Yield 0.073 g (53%). C16H13NO3Pd (373.5):
(456.8): calcd. C 63.1, H 4.0, N 6.1; found C 63.3, H 4.1, N 6.2. IR
calcd. C 51.4, H 3.5, N 3.8; found C 51.2, H 3.5, N 3.9. IR (Nujol):
(Nujol): ν = 1606 (s), 1577 (s), 1536 (s) cm–1. 1H NMR (300 MHz,
ν = 1610 (s), 1596 (vs), 1518 (s) cm–1. 1H NMR (300 MHz, CDCl ):
˜
˜
3
CDCl3): δ = 9.32 (d, J = 5.6 Hz, 1 H, Phpy), 8.11 (s, 1 H, HC=N,
N-Phsal), 7.81 (m, 1 H, Phpy), 7.60 (m, 3 H, 2 H N-Phsal + 1 H
Phpy), 7.34 (m, 4 H, Phpy), 7.27 (m, 3 H, N-Phsal), 6.99 (d, J =
8.7 Hz, 1 H, N-Phsal), 6.89 (m, 1 H, N-Phsal), 6.55 (m, 2 H, 1
Phpy + 1 N-Phsal), 5.78 (d, J = 7.8 Hz, 1 H, N-Phsal) ppm. FAB-
MS (positive mode): m/z = 456 [Pd(N-Phsal)(Phpy)]+.
δ = 9.15 (s, 1 H, sal, CH=O), 7.70 (d, J = 7.9 Hz, 1 H, sal), 7.30–
7.06 (m, 6 H, 4 Phox + 2sal), 6.57 (m, 1 H, sal), 4.74 (t, J = 9.4 Hz,
2 H, Phox, OCH2), 4.00 (t, J = 9.4 Hz, 2 H, Phox, NCH2) ppm.
FAB-MS (positive mode): m/z = 373 [Pd(sal)(Phox)]+.
[Pd(acac)(Phpy)] (I2): Yield 0.098 g (76%). C16H15NO2Pd (359.7):
calcd. C 53.4, H 4.2, N 3.9; found C 53.5, H 4.2, N 3.9. IR (Nujol):
˜
ν = 1604 (s), 1584 (vs), 1576 (s), 1516 (vs) cm–1. 1H NMR [Pd(N-Phsal)(Bzq)] (II4): Yield 0.124 g (78%). C26H18N2OPd
(300 MHz, CDCl3): δ = 8.72 (d, J = 5.5 Hz, 1 H, Phpy), 7.74 (m, (480.9): calcd. C 64.9, H 3.8, N 5.8; found C 65.0, H 3.9, N 5.8. IR
Eur. J. Inorg. Chem. 2008, 4797–4806
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4803

J. L. Serrano et al.
(Nujol): ν = 1604 (s), 1574 (vs), 1556 (s) cm–1. 1H NMR (300 MHz, H, 2-pcal), 7.23 (m, 2 H, Phox), 7.10 (m, 2 H, 2-pcal + Phox), 6.40
FULL PAPER
˜
CDCl3): δ = 9.41 (d, J = 5.2 Hz, 1 H, Bzq), 8.20 (d, J = 7.7 Hz, 1
H, Bzq), 8.06 (s, 1 H, –HC=N), 7.52 (m, 5 H, 3 Bzq + 2 NPhsal),
7.30 (m, 6 H, 3 Bzq + 3 NPhsal), 7.01 (d, J = 8.9 Hz, 1 H, N-
Phsal), 6.91 (m, 1 H, NPhsal), 6.50 (m, 1 H, Nphsal), 5.65 (d, J =
7.9 Hz, 1 H, N-Phsal) ppm. FAB-MS (positive mode): m/z = 480
[Pd(N-Phsal)(Bzq)]+.
(m, 1 H, 2-pcal), 4.78 (t, J = 9.6 Hz, 2 H, Phox, OCH2), 4.10 (t, J
= 9.6 Hz, 2 H, Phox, NCH2) ppm. FAB-MS (positive mode): m/z
= 347 [Pd(2-pcal)(Phox)]+.
[Pd(oxin)(Phpy)] (I7): Yield 0.096 g (66%). C20H14N2OPd (404.8):
calcd. C 59.4, H 3.5, N 6.9; found C 59.5, H 3.7, N 7.0. IR (Nujol):
1
ν = 1603 (s), 1567 (s), 1498 cm–1. H NMR (400 MHz, CDCl ): δ
˜
3
[Pd(N-Phsal)(Phox)] (III4): Yield 0.093 g (56%). C22H18N2O2Pd
= 9.13 (d, J = 5.6 Hz, 1 H, oxin), 8.88 (d, J = 5.2 Hz, 1 H, Phpy),
8.26 (d, J = 8.0 Hz, 1 H, oxin), 7.84 (m, 1 H, Phpy), 7.69 (d, J =
8.0 Hz, 1 H, Phpy), 7.48 (m, 4 H, Phpy), 7.22 (m, 3 H, 2 oxin + 1
Phpy), 7.07 (d, J = 7.6 Hz, 1 H, oxin), 6.92 (d, J = 8.6 Hz, 1 H,
(448.8): calcd. C 58.9, H 4.0, N 6.2; found C 59.1, H 4.2, N 6.1. IR
(Nujol): ν = 1628 (s), 1608 (s), 1558 (m) cm–1. 1H NMR (300 MHz,
˜
CDCl3): δ = 7.99 (s, 1 H, -HC=N), 7.94 (d, J = 7.7 Hz, 1 H, Phox),
7.34 (m, 7 H, 3 Phox + 4 N-Phsal), 7.16 (m, 3 H, N-Phsal), 7.05
(m, 1 H, N-Phsal), 6.58 (m, 1 H, N-Phsal), 4.25 (t, J = 9.6 Hz, 2
H, Phox, OCH2), 2.48 (t, J = 9.6 Hz, 2 H, Phox, NCH2) ppm.
FAB-MS (positive mode): m/z = 448 [Pd(N-Phsal)(Phox)]+.
oxin) ppm. FAB-MS (positive mode): m/z
= 404 [Pd(oxin)-
(Phpy)]+.
[Pd(oxin)(Bzq)] (II7): Yield 0.102 g (72%). C22H14N2OPd (428.8):
calcd. C 61.6, H 3.3, N 6.5; found C 61.7, H 3.4, N 6.5. IR (Nujol):
ν = 1620 (s), 1496 (s) cm–1. 1H NMR (300 MHz, CDCl ): δ = 9.14
[Pd(N-pClPhsal)(Phpy)] (I5): Yield 0.129 g (73%). C24H17ClN2OPd
˜
3
(491.3): calcd. C 58.7, H 3.5, N 5.7; found C 58.9, H 3.6, N 5.8. IR
(d, J = 5.5 Hz, 1 H, oxin), 8.78 (d, J = 5.0 Hz, 1 H, Bzq), 8.08 (m,
2 H, oxin + Bzq), 7.62 (d, J = 8.6 Hz, 1 H, Bzq), 7.47 (m, 5 H, 4
Bzq + 1 oxin), 7.24 (m, 2 H, oxin + Bzq), 7.04 (d, J = 7.5 Hz, 1
H, oxin), 6.84 (d, J = 8.6 Hz, 1 H, oxin) ppm. FAB-MS (positive
mode): m/z = 428 [Pd(oxin)(Bzq)]+.
(Nujol): ν = 1606 (s), 1574 (s), 1524 (s) cm–1. 1H NMR (300 MHz,
˜
CDCl3): δ = 9.28 (d, J = 5.8 Hz, 1 H, Phpy), 8.06 (s, 1 H, HC=N,
N-pClPhsal), 7.82 (m, 1 H, Phpy), 7.63 (d, J = 7.4 Hz, 1 H, Phpy),
7.53 (d, J = 8.4 Hz, 2 H, N-pClPhsal), 7.33 (m, 4 H, Phpy), 7.27
(m, 2 H, N-pClPhsal), 6.98 (d, J = 8.7 Hz, 1 H, N-pClPhsal), 6.92
(m, 1 H, N-pClPhsal), 6.65 (m, 1 H, N-pClPhsal), 6.55 (m, 1 H,
Phpy), 5.86 (d, J = 7.8 Hz, 1 H, N-pClPhsal) ppm. FAB-MS (posi-
tive mode): m/z = 490 [Pd(N-pClPhsal)(Phpy)]+.
[{Pd(µ-spy)(Phpy)}2] (I8): Yield 0.200 g (75%). C32H24N4Pd2S2
(741.5): calcd. C 51.8, H 3.3, N 7.6, S 8.6; found C 51.7, H 3.2, N
7.6, S 8.4. IR (Nujol): ν = 1604 (s), 1576 (s), 1552 (s) cm–1. 1H
˜
NMR (300 MHz, CDCl3): δ = 8.65 (d, J = 5.7 Hz, 2 H, Phpy),
7.81 (m, 4 H, Phpy), 7.62 (m, 2 H, Phpy), 7.50 (m, 4 H, 2 Phpy +
2 spy), 7.13 (m, 4 H, 2 Phpy + 2 spy), 6.97 (m, 4 H, 2 Phpy + 2
spy), 6.75 (m, 2 H, Phpy), 6.43 (m, 2 H, spy) ppm. FAB-MS (posi-
tive mode): m/z = 741 [{Pd(µ-spy)(Phpy)}2]+.
[Pd(N-pClPhsal)(Bzq)] (II5): Yield 0.121 g (71%). C26ClH17N2OPd
(515.3): calcd. C 60.6, H 3.3, N 5.4; found C 60.7, H 3.4, N 5.4. IR
(Nujol): ν = 1608 (s), 1570 (s), 1522 (m) cm–1. 1H NMR (300 MHz,
˜
CDCl3): δ = 9.36 (d, J = 5.2 Hz, 1 H, Bzq), 8.19 (d, J = 7.8 Hz, 1
H, Bzq), 8.00 (s, 1 H, –HC=N), 7.59 (d, J = 8.7 Hz, 1 H, Bzq),
7.48 (m, 4 H, 2 Bzq + 2 N-pClPhsal), 7.31 (m, 4 H, 2 Bzq + 2 N-
pClPhsal), 7.20 (m, 1 H, Bzq), 6.96 (m, 2 H, N-pClPhsal), 6.51 (m,
1 H, N-pClPhsal), 5.76 (d, J = 8.0 Hz, 1 H, N-pClPhsal) ppm.
FAB-MS (positive mode): m/z = 515 [Pd(N-pClPhsal)(Bzq)]+.
[{Pd(µ-spy)(Bzq)}2] (II8): Yield 0.188 g (72%). C36H24N4Pd2S2
(789.6): calcd. C 54.8, H 3.1, N 7.1, S 8.1; found C 54.9, H 3.2, N
7.1, S 8.0. IR (Nujol): ν = 1622 (s), 1566 (s) cm–1. 1H NMR
˜
(300 MHz, CDCl3): δ = 8.64 (d, J = 5.2 Hz, 2 H, Bzq), 7.84 (m, 4
H, Bzq), 7.49 (d, J = 7.7 Hz, 2 H, spy), 7.18 (m, 4 H, 2 Bzq + 2
spy) 7.06 (m, 6 H, 4 Bzq + 2 spy), 6.70 (m, 4 H, Bzq), 6.36 (m, 2
H, spy) ppm. FAB-MS (positive mode): m/z = 789 [{Pd(µ-
spy)(Bzq)}2]+.
[Pd(N-pClPhsal)(Phox)]
(III5):
Yield
0.095 g
(53%).
C22H17ClN2O2Pd (483.3): calcd. C 54.7, H 3.6, N 5.8; found C
54.9, H 3.7, N 5.7. IR (Nujol): ν = 1628 (s), 1604 (s), 1518 (m) cm–1.
˜
1H NMR (300 MHz, CDCl3): δ = 7.94 (m, 2 H, 1 Phox + 1, –
HC=N), 7.33 (m, 5 H, 3 Phox + 2 N-pClPhsal), 7.15 (m, 4 H, N-
pClPhsal), 6.55 (m, 2 H, N-pClPhsal), 4.26 (t, J = 9.6 Hz, 2 H,
Phox, OCH2), 2.52 (t, J = 9.6 Hz, 2 H, Phox, NCH2) ppm. FAB-
MS (positive mode): m/z = 482 [Pd(N-pClPhsal)(Phox)]+.
[{Pd(µ-spy)(Phox)}2] (III8): Yield 0.164 g (61%). C28H24N4O2Pd2S2
(725.5): calcd. C 46.4, H 3.3, N 7.7, S 8.8; found C 46.5, H 3.2, N
7.6, S 8.7. IR (Nujol): ν = 1644 (s), 1586 (s) cm–1. 1H NMR
˜
(300 MHz, CDCl3): δ = 8.52 (d, J = 6.0 Hz, 2 H, spy), 7.89 (d, J
= 7.5 Hz, 2 H, Phox), 7.37 (d, J = 8.4 Hz, 2 H, spy), 7.04 (m, 4 H,
2 Phox + 2 spy), 6.86 (m, 2 H, spy), 6.68 (m, 4 H, Phox), 4.41 (m,
4 H, Phox), 4.24 (m, 2 H, Phox), 3.35 (m, 2 H, Phox) ppm. FAB-
MS (positive mode): m/z = 725 [{Pd(µ-spy)(Phox)}2]+.
[Pd(2-pcal)(Phpy)] (I6): Yield 0.086 g (67%). C16H12N2OPd (355.7):
calcd. C 54.2, H 3.4, N 7.9; found C 54.1, H 3.6, N 7.8. IR (Nujol):
ν = 1604 (s), 1564 (vs) cm–1. 1H NMR (300 MHz, CDCl ): δ = 8.79
˜
3
(d, J = 5.4 Hz, 1 H, Phpy), 8.67 (s, 1 H, 2-pcal), 7.78 (m, 1 H,
Phpy), 7.60 (d, J = 8.1 Hz, 1 H, Phpy), 7.50 (m, 3 H, 2 Phpy + 1
2-pcal), 7.41 (m, 1 H, 2-pcal), 7.13 (m, 3 H, Phpy), 6.36 (m, 1 H,
∧
∧
Preparation of complexes [Pd{S(S)P(OEt)2}(C N)] [C N = (Phpy)
(I9), (Bzq) (II9) or (Phox) (III9)].
2-pcal) ppm. FAB-MS (positive mode): m/z
= 355 [Pd(2-
The new complexes were obtained by treating a CH2Cl2 suspension
(20 mL) of the different precursors I–III (0.100 g) with the corre-
sponding amount of [NH4][S(S)P(OEt)2] (molar ratio 1:2). Once
the suspension was dissolved (ca. 30 min) it was concentrated under
reduced pressure until ca. one fifth of the initial volume. Slow ad-
dition of diethyl ether caused the formation of the complexes,
which were filtered off, washed with water and diethyl ether, and
air-dried. The compounds were recrystallised from dichlorometh-
ane/diethyl ether.
pcal)(Phpy)]+.
[Pd(2-pcal)(Bzq)] (II6): Yield 0.087 g (69%). C18H12N2OPd (379.7):
calcd. C 57.1, H 3.2, N 7.4; found C 57.0, H 3.3, N 7.4. IR (Nujol):
ν = 1618 (s), 1568 (vs) cm–1. 1H NMR (300 MHz, CDCl ): δ = 8.76
˜
3
(d, J = 5.2 Hz, 1 H, Bzq), 8.64 (s, 1 H, 2-pcal), 8.07 (d, J = 8.1 Hz,
1 H, Bzq), 7.50 (m, 4 H, Bzq), 7.37 (m, 2 H, Bzq), 7.29 (m, 1 H,
2-pcal), 7.09 (m, 1 H, 2-pcal), 6.38 (m, 1 H, 2-pcal) ppm. FAB-MS
(positive mode): m/z = 379 [Pd(2-pcal)(Bzq)]+.
[Pd(2-pcal)(Phox)] (III6): Yield 0.068 g (53%). C14H12N2O2Pd
[Pd{S2P(OEt)2}(Phpy)]
(I9):
Yield
0.127 g
(79%).
(347.7): calcd. C 48.5, H 3.5, N 8.1; found C 48.6, H 3.6, N 8.1. IR
C15H18NO2PPdS2 (445.8): calcd. C 40.4, H 4.1, N 3.1, S 14.4;
(Nujol): ν = 1640 (s), 1620 (s) cm–1. 1H NMR (300 MHz, CDCl ): δ
found C 40.5, H 4.0, N 3.0, S 14.5. IR (Nujol): ν = 1603 (s), 1576
˜
˜
3
= 8.64 (s, 1 H, 2-pcal), 7.51 (d, J = 7.5 Hz, 1 H, Phox), 7.41 (m, 1
(s), 1014 (vs), 956 (vs), 650 (vs), 641 (vs) cm–1. 1H NMR (300 MHz,
4804
www.eurjic.org
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 4797–4806

Cyclopalladated Di-µ-hydroxo Complexes
CDCl3): δ = 8.54 (d, J = 5.4 Hz, 1 H, Phpy), 7.86 (m, 1 H, Phpy), filtered off, washed with water and diethyl ether, and air-dried. The
7.75 (d, J = 8.1 Hz, 1 H, Phpy), 7.53 (m, 1 H, Phpy), 7.29 (m, 1 compounds were recrystallised from dichloromethane/diethyl ether.
H, Phpy), 7.15 (m, 3 H, Phpy), 4.25 (m, 4 H, CH2-O), 1.35 (t, J =
[Pd(S2CNEt2)(Phpy)] (I10): Yield 0.099 g (67%). C16H18N2PdS2
7.0 Hz, 6 H, CH3) ppm. 31P NMR (300 MHz, CDCl3): δ = 104.8
(408.9): calcd. C 47.0, H 4.4, N 6.9, S 15.7; found C 47.1, H 4.5,
(s) ppm. FAB-MS (positive mode): m/z = 445 [Pd{S2P(OEt)2}-
1
N 6.8, S 15.5. IR (Nujol): ν = 1599 (s), 1502 (s), 987 (s) cm–1. H
˜
(Phpy)]+.
NMR (300 MHz, CDCl3): δ = 8.38 (d, J = 5.4 Hz, 1 H, Phpy),
[Pd{S2P(OEt)2}(Bzq)] (II9): Yield 0.131 g (84%). C17H18NO2PPdS2
7.78 (m, 2 H, Phpy), 7.54 (m, 1 H, Phpy), 7.12 (m, 4 H, Phpy),
(468.9): calcd. C 43.5, H 3.9, N 3.0, S 13.6; found C 43.6, H 4.0,
3.86 (q, J = 7.2 Hz, 4 H, CH2), 1.33 (m, 6 H, CH3) ppm. FAB-MS
N 3.0, S 13.8. IR (Nujol): ν = 1616 (s), 1016 (vs), 965 (vs), 656 (positive mode): m/z = 408 [Pd(S2CNEt2)(Phpy)]+.
˜
1
(vs), 639 (vs) cm–1. H NMR (300 MHz, CDCl3): δ = 8.76 (d, J =
[Pd(S2CNEt2)(Bzq)] (II10): Yield 0.099 g (69%). C18H18N2PdS2
5.1 Hz, 1 H, Bzq), 8.30 (d, J = 7.8 Hz, 1 H, Bzq), 7.77 (d, J =
(432.9): calcd. C 49.9, H 4.2, N 6.5, S 14.8; found C 50.1, H 4.3,
8.7 Hz, 1 H, Bzq), 7.61 (m, 2 H, Bzq), 7.48 (m, 3 H, Bzq), 4.29 (m,
1
N 6.6, S 14.6. IR (Nujol): ν = 1614 (s), 1501 (s), 989 (s) cm–1. H
˜
4 H, CH2),1.42 (t, J = 6.9 Hz, 6 H, CH3) ppm. 31P NMR
(300 MHz, CDCl3): δ = 105.2 (s) ppm. FAB-MS (positive mode):
m/z = 468 [Pd{S2P(OEt)2}(Bzq)]+.
NMR (300 MHz, CDCl3): δ = 8.65 (d, J = 5.1 Hz, 1 H, Bzq), 8.27
(d, 1 H, Bzq), (d, J = 8.1 Hz, 1 H), 7.77 (d, J = 8.7 Hz, 1 H, Bzq),
7.59 (m, 2 H, Bzq), 7.43 (m, 3 H, Bzq), 3.90 (q, J = 7.2 Hz, 4 H,
CH2), 1.40 (m, 6 H, CH3) ppm. FAB-MS (positive mode): m/z =
432 [Pd(S2CNEt2)(Bzq)]+.
[Pd{S2P(OEt)2}(Phox)] (III9): Yield 0.086 g (53%). C18H14N2O2Pd
(396.72): calcd. C 54.5, H 3.6, N 7.1, S 14.7; found C 54.7, H 3.7,
N 7.1, S 14.8. IR (Nujol): ν = 1626 (s), 1020 (vs), 960 (vs), 648
˜
[Pd(S2CNEt2)(Phox)]
C14H18N2OPdS2 (400.8): calcd. C 41.9, H 4.5, N 7.0, S 16.0; found
C 42.1, H 4.6, N 7.1, S 15.9. IR (Nujol): ν = 1632 (s), 1522 (s),
(III10):
Yield
0.067 g
(45%).
(vs), 636 (vs) cm–1. 1H NMR (300 MHz, CDCl3): δ = 7.28 (m, 2
H, Phox), 7.19 (m, 1 H, Phox), 7.07 (m, 1 H, Phox), 4.74 (t, J =
9.4 Hz, 2 H, Phox, OCH2), 4.22 (m, 4 H, CH2), 4.03 (t, J = 9.4 Hz,
2 H, Phox, NCH2), 1.39 (t, J = 7.0 Hz, 6 H, CH3) ppm. 31P NMR
(300 MHz, CDCl3): δ = 105.3 (s) ppm. FAB-MS (positive mode):
m/z = 437 [Pd{S2P(OEt)2}(Phox)]+.
˜
1016 (s) cm–1. 1H NMR (300 MHz, CDCl3): δ = 7.32 (m, 1 H,
Phox), 7.11 (m, 3 H, Phox), 4.73 (t, J = 9.5 Hz, 2 H, Phox, OCH2),
4.01 (t, J = 9.5 Hz, 2 H, Phox, NCH2), 3.71 (q, J = 7.1 Hz, 4 H,
CH2), 1.27 (m, 6 H, CH3) ppm. FAB-MS (positive mode): m/z =
400 [Pd(S2CNEt2)(Phox)]+.
∧
∧
Preparation of complexes [Pd(S2CNEt2)(C N)] [C N = (Phpy)
(I10), (Bzq) (II10) or (Phox) (III10)].
Crystal Structure Determination of [Pd(sal)(Phpy)] (I1), [Pd(bzac)-
(Phpy)] (I3), [Pd(2-pcal)(Phpy)] (I6), [Pd(N-Phsal)(Bzq)] (II4),
[Pd(N-pClPhsal)(Bzq)] (II5) and [Pd(N-pClPhsal)(Phox)] (III5):
Data collection for I1 and I6 was performed at 173 K with a Sie-
mens P4 diffractometer. The data for I3, II4 and II5 were obtained
at 100 K with a Bruker Smart CCD diffractometer with a nominal
crystal to detector distance of 4.5 cm. Diffraction data were col-
In separate experiments, a CH2Cl2 suspension (20 mL) of the dif-
ferent precursors I–III (0.100 g) was added to Et2NH (molar ratio
1:2) along with a slight excess of carbon disulfide. Once the suspen-
sion was dissolved (ca. 30 min) it was concentrated under reduced
pressure until ca. one fifth of the initial volume. Slow addition of
diethyl ether caused the formation of the complexes, which were
Table 3. Crystal data and structure refinement for compounds I1, I3, I6, II4, II5 and III5.
?>Compound
I1
I3
I6
II4
II5
III5
Empirical formula
C18H13NO2Pd
381.69
C21H17NO2Pd
421.76
C16H12N2OPd
354.68
C26H18N2OPd
480.82
C26H17ClN2OPd
517.27
C22H17ClN2O2Pd
483.23
Formula weight [gmol–1]
Temperature [K]
173(2)
100(2)
173(2)
100(2)
100(2)
293(2)
Radiation, λ [Å]
Crystal system
Space group
0.71073
monoclinic
P21/n
0.71073
monoclinic
P21/n
0.71073
trigonal
R-3
0.71073
monoclinic
Cc
0.71073
monoclinic
P2/a
0.71073
monoclinic
Cc
Unit cell dimensions
a [Å]
b [Å]
c [Å]
α [°]
18.489(2)
8.7952(10)
18.502(2)
90
7.6503(3)
19.7337(8)
11.6607(5)
90
32.1803(17)
32.1803(17)
13.4614(10)
90
19.6091(9)
6.2204(3)
15.9310(7)
90
15.5738(6)
6.3513(2)
20.8049(8)
90
16.7630(5)
20.9270(6)
17.9880(7)
90
β [°]
107.02(10)
90
2877.0(5)
8
108.53
90
1669.14(12)
4
1.678
1.126
90
120
12072.6(13)
36
1. 464
97.1710(10)
90
1928.01(15)
4
1.656
0.984
93.7530(10)
90
2053.48(13)
4
1.667
1.056
112.5500(10)
90
5827.7(3)
12
1.652
1.113
γ [°]
Volume [Å3]
Z
Calculated density [mgm–3]
1.762
Absorption coefficient [mm–1] 1.296
1.149
F(000)
1520
848
5280
968
1032
2904
Theta range for collection
Reflections collected
Independent reflections
Refinement method
Data/parameters/restrains
Goodness-of-fit on F2
Final R indices [I Ͼ 2σ(I)]
1.85 to 27.49°
17930
6604
2.06 to 28.09
19040
3842
3.04 to 25.00°
9986
2.09 to 28.18°
10529
4236
2.62 to 28.14°
22431
4765
1.64 to 27.52°
11452
11451
4726
full-matrix least-squares on F2
6604/501/0
0.843
R1 = 0.0316
wR2 = 0.0732
R1 = 0.0496
wR2 = 0.0806
3842/226/0
1.044
R1 = 0.0222
wR2 = 0.0541
R1 = 0.0231
wR2 = 0.0547
4726/361/0
0.890
R1 = 0.0323
wR2 = 0.0620
R1 = 0.0551
wR2 = 0.0667
4236/271/2
0.852
R1 = 0.0209
wR2 = 0.0511
R1 = 0.0214
wR2 = 0.0515
4765/280/0
1.095
R1 = 0.0208
wR2 = 0.0543
R1 = 0.0216
wR2 = 0.0550
11451/757/2
0.978
R1 = 0.0723
wR2 = 0.1572
R1 = 0.1733
wR2 = 0.2157
R indices (all data)
Eur. J. Inorg. Chem. 2008, 4797–4806
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4805

J. L. Serrano et al.
FULL PAPER
rano, J. Pérez, M. C. Ramírez de Arellano, G. López, E. Mol-
ins, Inorg. Chim. Acta 1999, 295, 136–145.
lected based on a ω scan run. A total of 2524 frames were collected
at 0.3° intervals and 10 s per frame. The diffraction frames were
integrated using the SAINT package[22] and corrected for absorp-
tion with the SADABS program.[23] The data collection for com-
plex III5 was performed at 293 K with a Nonius Kappa-CCD sin-
gle-crystal diffractometer. The crystal-detector distance was fixed
at 40 mm, and a total of 124 images were collected using the oscilla-
tion method, with scan angle per frame, 2° oscillation and a 40 s
exposure time per image. The data collection strategy was calcu-
lated with the program Collect.[24] Data reduction and cell refine-
ment were performed with the programs HKL Denzo and Scale-
pack.[25]
[9] a) E. C. Constable, A. M. W. Cargill Thompson, T. A. Leese,
D. G. F. Reese, D. A. Tocher, Inorg. Chim. Acta 1991, 182, 93–
100; b) D. L. Weaver, Inorg. Chem. 1970, 9, 2250–2258; c)
M. A. Gutiérrez, G. R. Newkome, J. Selbin, J. Organomet.
Chem. 1980, 202, 341–350; d) J. M. Vila, M. Gayoso, M. Per-
eira, A. Romar, J. J. Fernández, M. Thornton-Pett, J. Or-
ganomet. Chem. 1991, 401, 385–394; e) M. M. Mdleleni, J. S.
Bridgewater, R. J. Watts, P. C. Ford, Inorg. Chem. 1995, 34,
2334–2342; f) C. A. Craig, R. J. Watts, Inorg. Chem. 1989, 28,
309; g) H. Adams, N. A. Bailey, T. N. Briggs, J. A. McCleverty,
H. M. Colquhoun, D. J. Williams, J. Chem. Soc., Dalton Trans.
1986, 813–819; h) I. Aiello, A. Crispini, M. Ghedini, M.
La Deda, F. Barigelletti, Inorg. Chim. Acta 2000, 308, 121–128.
[10] a) G. Sánchez, J. L. Serrano, M. A. Moral, J. Pérez, E. Molins,
G. López, Polyhedron 1999, 18, 3057–3064; b) J. Pérez, G.
Sánchez, J. García, J. L. Serrano, G. López, Thermochim. Acta
2000, 362, 59–70; c) J. L. Serrano, L. García, J. Pérez, E. Pérez,
J. Vives, G. Sánchez, G. López, E. Molins, A. Guy Orpen, Poly-
hedron 2002, 21, 1589–1596; d) I. J. S. Fairlamb, A. R. Kapdi,
A. F. Lee, G. Sánchez, G. López, J. L. Serrano, L. García, J.
Pérez, E. Pérez, Dalton Trans. 2004, 3970–3981.
The structures were solved by direct methods[26] and refined by full-
matrix least-squares techniques using anisotropic thermal param-
eters for non-hydrogen atoms[25] (Table 3).
CCDC-686575 (for I1), -686576 (for I3), -686577 (for I6), -686578
(for II4), -686579 (for II5), -686580 (for III5) contain the supple-
mentary crystallographic data for this paper. These data can be
obtained free of charge from The Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
[11] a) M. Ghedini, I. Aiello, A. Crispini, A. Golemme, M.
La Deda, D. Pucci, Coord. Chem. Rev. 2006, 250, 1373–1390;
b) I. Omae, J. Organomet. Chem. 2007, 692, 2608–2632; c) K.
Gogula, D. Sames, Science 2006, 312, 67; d) J. Dupont, C. S.
Consorte, J. Spencer, Chem. Rev. 2005, 105, 2527–2572.
[12] M. Ghedini, D. Pucci, A. Crispini, I. Aiello, F. Barigelletti, A.
Gessi, O. Francescangeli, Appl. Organomet. Chem. 1999, 13,
565–581.
Acknowledgments
Financial support for this work by Dirección General de Investiga-
ción (project-CTQ2005-09231-C02-01/02) and Fundación Séneca
de la Región de Murcia (00484/PI/04) is gratefully acknowledged.
[13] M. Ghedini, I. Aiello, M. La Deda, A. Grisolia, Chem. Com-
mun. 2003, 2198–2199.
[14] a) I. Aiello, M. Ghedini, M. La Deda, J. Lumin. 2002, 96, 249–
259; b) T. Pugliese, N. Godbert, M. La Deda, I. Aiello, M.
Ghedini, Chem. Phys. Lett. 2005, 410, 201–203.
[15] I. P. Smoliakova, K. J. Keuseman, D. C. Haagenson, D. M.
Wellmann, P. B. Colligan, N. A. Kataeva, A. V. Churakov,
L. G. KuzЈmina, V. V. Dunina, J. Organomet. Chem. 2000, 603,
86–97.
[16] M. Beller, T. H. Riermeier, W. Mägerlein, T. E. Müller, W.
Scherer, Polyhedron 1998, 17, 1165–1176.
[17] W. Purcell, S. S. Basson, J. G. Leipoldt, A. Roodt, H. Preston,
Inorg. Chim. Acta 1995, 234, 153–156.
[18] J. L. Serrano, L. García, J. Pérez, E. Pérez, J. García, G.
Sánchez, G. López, I. J. S. Fairlamb, M. Liu, Polyhedron 2008,
27, 1699–1706.
[19] J. Pérez, L. García, E. Pérez, J. L. Serrano, J. F. Martínez, G.
Sánchez, G. López, A. Espinosa, M. Liu, F. Sanz, New J.
Chem. 2003, 27, 1490–1496.
[20] M. Kessler, J. Pérez, M. C. Bueso, L. García, E. Pérez, J. L.
Serrano, R. Carrascosa, Acta Crystallogr., Sect. B 2007, 63,
869–878.
[21] A. S. Ionkin, W. J. Marshall, Y. Wang, Organometallics 2005,
24, 619–627.
[22] SAINT, version 6.22, Bruker AXS Inc.
[23] G. M. Sheldrick, SADABS, University of Göttingen, 1996.
[24] COLLECT, Nonius BV, 1997–200.
[25] Z. Otwinowski, W. Minor, DENZO-SCALEPACK “Processing
of X-ray Diffraction Data Collected in Oscillation Mode”,
Methods in Enzymology, vol. 276, Macromolecular Crystal-
lography, part A (Eds.: C. W. Carter, R. M. Sweet Jr), Aca-
demic Press, 1997, p. 307–326.
[26] G. M. Sheldrick, SHELX-97. Programs for Crystal Structure
Analysis, release 97-2, University of Göttingen, Germany, 1998.
Received: April 30, 2008
[1] R. A. Adrian, S. Zhu, D. R. Powell, G. A. Broker, E. R. T. Tie-
kink, J. A. Walmsley, Dalton Trans. 2007, 4399–4404 and refer-
ences cited therein.
[2] a) M. Sodeoka, Y. Hamashima, Pure Appl. Chem. 2006, 78,
477–494; b) G. S. Yang, R. Miao, I. Z. Li, J. Hong, S. M. Zhao,
Z. J. Guo, L. G. Zhu, Dalton Trans. 2005, 1613–1619; c) S.
Kannan, A. J. James, P. R. Sharp, Inorg. Chim. Acta 2003, 345,
8–14; d) S. Kannan, A. J. James, P. R. Sharp, Polyhedron 2000,
19, 155–163 and references cited therein.
[3] R. A. Adrian, G. A. Broker, E. R. T. Tiekink, J. A. Walmsley,
Inorg. Chim. Acta 2008, 361, 1261–1266.
[4] a) U. Anandhi, T. Holbert, D. Lueng, P. R. Sharp, Inorg. Chem.
2003, 42, 1282–1295; b) P. R. Sharp, J. Chem. Soc., Dalton
Trans. 2000, 2647–2657.
[5] B. Longato, G. Bandoli, A. Dolmella, Eur. J. Inorg. Chem.
2004, 1092–1099.
[6] a) L. Díez, P. Espinet, J. A. Miguel, J. Chem. Soc., Dalton
Trans. 2001, 1189–1195; b) P. Espinet, C. Hernández, J. M.
Martín-Álvarez, J. A. Miguel, Inorg. Chem. 2004, 43, 843–845.
[7] a) J. Ruiz, N. Cutillas, V. Rodríguez, J. Sampedro, G. López,
P. A. Chalonner, P. B. Hitchcock, J. Chem. Soc., Dalton Trans.
1999, 2939–2946; b) G. Sánchez, J. García, D. Meseguer, J. L.
Serrano, L. García, J. Pérez, G. López, Dalton Trans. 2003,
4709–4717; c) G. Sánchez, J. Vives, G. López, J. L. Serrano, L.
García, J. Pérez, Eur. J. Inorg. Chem. 2005, 2360–2367; d) J.
Pérez, J. L. Serrano, J. M. Galiana, F. L. Cumbrera, A. L. Or-
tiz, G. Sánchez, J. García, Acta Crystallogr., Sect. B 2007, 63,
75–80.
[8] a) J. L. Serrano, I. J. S. Fairlamb, G. Sánchez, L. García, J.
Pérez, J. Vives, G. López, C. M. Crawforth, R. J. K. Taylor, Eur.
J. Inorg. Chem. 2004, 2706–2715; b) J. Ruiz, V. Rodríguez, G.
López, J. Casabó, E. Molins, C. Miravitlles, Organometallics
1999, 18, 1177–1184 and references cited therein; c) G.
Sánchez, J. L. Serrano, J. García, G. López, J. Pérez, E. Molins,
Inorg. Chim. Acta 1999, 287, 37–46; d) G. Sánchez, J. L. Ser-
Published Online: September 10, 2008
4806
www.eurjic.org
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 4797–4806