New tris(pyrazolyl)triazine and pyrazolylpyridine gold(I) and palladium(II) derivatives based on the 3,5-bis(4-butoxyphenyl)pyrazole group - Architectures with different types of bonding interactions

Article abstract of DOI:10.1002/ejic.200300039

The 3,5-bis(4-butoxyphenyl)pyrazolyl group (Pz^bp2) has been used as a building block for mono- and polymetallic derivatives of 2,4,6-tris[3,5-bis(4-butoxyphenyl)pyrazol-1-yl]-1,3,5-triazine (TPz^bp2Tz, 1), 2-[3,5-bis(4-butoxyphenyl)pyrazol-1-yl]pyridine (Pz^bp2Py, 2), and 3,5-bis(4-butoxyphenyl)pyrazole (HPz^bp2, 3) ligands. The synthesis and characterisation of the new hexadentate ligand 1 are described, together with the chemistry of its metal complexes containing [Pd(η³-C₃H₅)]⁺ and [Au(PPh₃)]⁺ fragments. The related complexes containing Pz^bp2Py (2) were also studied and their structural characteristics were compared to those of the TPz^bp2Tz species. The role of the counter-ion on the supramolecular assembly of complexes containing the HPz^bp2 ligand 3 was made clear by the X-ray structures of [Pd(η³-C₃H₅)(HPz^bp2) ₂](BF₄) and [Au(HPz^bp2)(PPh₃)](NO₃). Hydrogen bonds and/or bonding interactions are responsible for pseudohelical one-dimensional polymers or supramolecular columnar arrays, respectively. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.

Full text of DOI:10.1002/ejic.200300039

FULL PAPER
New Tris(pyrazolyl)triazine and Pyrazolylpyridine Gold( ) and Palladium(II)
I
Derivatives Based on the 3,5-Bis(4-butoxyphenyl)pyrazole Group ؊
Architectures with Different Types of Bonding Interactions
[a]
[a]
[b]
[b]
´
Rosa M. Claramunt, Pilar Cornago, Mercedes Cano,* Jose V. Heras,
M. Luz Gallego,[b] Elena Pinilla,[b,c] and M. Rosario Torres[c]
Keywords: Gold / Hydrogen bonds / Palladium / Supramolecular Chemistry / Triazine
The 3,5-bis(4-butoxyphenyl)pyrazolyl group (Pzbp2) has been
used as a building block for mono- and polymetallic derivat-
ives of 2,4,6-tris[3,5-bis(4-butoxyphenyl)pyrazol-1-yl]-1,3,5-
triazine (TPzbp2Tz, 1), 2-[3,5-bis(4-butoxyphenyl)pyrazol-1-
yl]pyridine (Pzbp2Py, 2), and 3,5-bis(4-butoxyphenyl)pyrazole
characteristics were compared to those of the TPzbp2Tz spe-
cies. The role of the counter-ion on the supramolecular as-
sembly of complexes containing the HPzbp2 ligand 3 was
made clear by the X-ray structures of [Pd(η3-
C3H5)(HPzbp2)2](BF4) and [Au(HPzbp2)(PPh3)](NO3). Hydro-
(HPzbp2, 3) ligands. The synthesis and characterisation of the gen bonds and/or bonding interactions are responsible for
new hexadentate ligand 1 are described, together with the
chemistry of its metal complexes containing [Pd(η3-C3H5)]+
and [Au(PPh3)]+ fragments. The related complexes con-
pseudohelical one-dimensional polymers or supramolecular
columnar arrays, respectively.
( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
taining Pzbp2Py (2) were also studied and their structural Germany, 2003)
Introduction
ful to provide stable complexes containing N,NЈ-bidentate
ligands,[13] making these metal groups suitable for our coor-
dinative purposes.
Research into the self-assembly of transition metal com-
plexes is of increasing interest for the design of supra-
molecular structures.[1Ϫ7] Of the strategies currently in use
to control molecular aggregates, non-covalent interactions
such as metal coordination and hydrogen bonding have
been of much use in recent years.[8,9]
Our group has acquired some expertise in studying metal
complexes containing long chain-substituted pyrazole
groups. The coordinative ability of 3,5-bis(4-butoxyphenyl)-
pyrazolate towards gold() derivatives, for example, yielded
complexes such as [Au(Pzbp2)(PPh3)], with supramolecular
aurophilic Au···Au interactions,[10a,11,12] and [(PPh3)Au(µ-
Pzbp2)Au(PPh3)]ϩ, presenting intramolecular Au···Au con-
tacts and molecular entities controlled by interactions
through the corresponding counter-ions.[10b] Similar effects
have also been described for related silver() derivatives.[5]
On the other hand, π-allyl palladium() fragments are use-
In addition, 1,3,5-triazine ligands have also been shown
to be versatile for the preparation of metal complexes with
a large variety of structural architectures.[14]
To extend these results, we decided to study new metal
derivatives of a polydentate ligand, 2,4,6-tris[3,5-bis(4-but-
oxyphenyl)pyrazol-1-yl]-1,3,5-triazine (TPzbp2Tz, 1), con-
taining three pyrazole groups in addition to the three nitro-
gen atoms of the triazine core (Scheme 1). Their coordi-
nation capability towards [Pd(η3-C3H5)]ϩ and [Au(PPh3)]ϩ
fragments is analysed in a search for polymetallic com-
plexes. The nature of the counter-ion and the effect of the
[a]
´
´
´
Departamento de Quımica Organica y Biologıa, Facultad de
´
Ciencias, Universidad de Educacion a Distancia,
Senda del Rey, 28040 Madrid, Spain
[b]
[c]
´
´
Departamento de Quımica Inorganica I, Facultad de Ciencias
´
Quımicas, Universidad Complutense,
28040 Madrid, Spain
Fax: (internat.) ϩ34Ϫ91/3944352
E-mail: mmcano@quim.ucm.es
´
Laboratorio de Difraccion de Rayos-X, Facultad de Ciencias
´
Quımicas, Universidad Complutense,
28040 Madrid, Spain
Scheme 1
Eur. J. Inorg. Chem. 2003, 2693Ϫ2704
DOI: 10.1002/ejic.200300039
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M. Cano et al.
FULL PAPER
OR substituents on the pyrazole groups are also considered tion band at 3400 cmϪ1).[17] Two ν(BF) absorption bands
Ϫ
as elements for potential supramolecular architectures.
at 1067 and 1039 cmϪ1, from the BF4 group, were also
The chemistry of the new complexes is described and observed and support the presence of interactions towards
compared to that observed on treatment of the same metal that counter-ion (two bands agree with a distorted tetra-
fragments with bidentate 2-[3,5-bis(4-butoxyphenyl)pyra- hedral geometry in contrast to the broad single band at
zol-1-yl]pyridine (2) and monodentate 3,5-bis(4-butoxy- 1070 cmϪ1 for the tetrahedral free anion).[18]
phenyl)pyrazole (3) ligands, regarded as building blocks
On the other hand, the 1H NMR results indicate the
presenting coordinative positions related to those of the presence of an η3-allyl group, together with two equivalent
new ligand TPzbp2Tz (1) (Scheme 1).
coordinated pyrazole ligands, each of these showing non-
equivalence in the two butoxyphenyl substituents. The al-
lylic part of the spectrum can be interpreted in terms of a
symmetrical η3-allyl group, so there are three different pro-
ton environments: Hmeso in the central carbon, Hs (syn) and
Ha (anti). The signal at highest field (δ ϭ 3.18 ppm), and
with the largest coupling constant (J ϭ 12.7), is assigned to
the Ha protons nearest to the metal, with the other doublet
signal at δ ϭ 3.92 ppm (J ϭ 6.8) being assigned to the Hs
protons. The Hmeso signal appears a as multiplet at lower
field (δ ϭ 5.70 ppm).
Results and Discussion
Synthesis and Structural Characterisation of the 2,4,6-
Tris[3,5-bis(4-butoxyphenyl)pyrazol-1-yl]-1,3,5-triazine
Ligand (TPzbp2Tz, 1)
We treated 3,5-bis(4-butoxyphenyl)pyrazole (3) with
2,4,6-trichlorotriazine (stoichiometry 3:1) in dry THF
under argon atmosphere, by the procedure that we have al-
ready described for several 2,4,6-tris(pyrazol-1-yl)-2,4,6-
triazines,[15] to obtain the 2,4,6-tris[3,5-bis(4-butoxyphenyl)-
pyrazol-1-yl]-1,3,5-triazine ligand (1, TPzbp2Tz) in a 30%
yield.
This ligand was fully characterized by spectroscopic tech-
niques and its main properties in relation to the gold() and
palladium() complexes are commented on in the follow-
ing sections.
Compound 5 was prepared by addition of one equivalent
of 3 to a dichloromethane solution of [Au(NO3)(PPh3)],
previously obtained by treatment of [AuCl(PPh3)] with
AgNO3.[19] A ν(NH) absorption band at 3250 cmϪ1 in the
IR spectrum of 5 suggests the presence of hydrogen bond
interactions, analogously to what was observed in 4. A band
Ϫ
for the ionic NO3 group at 1384 cmϪ1 [18,19] agrees with
the formation of a cationic complex [Au(HPzbp2)(PPh3)]ϩ.
On the other hand, a 1:1 PPh3/HPz ratio is established
from the 1H NMR spectrum (clearly observed from the 15:1
Treatment of [Pd(η3-C3H5)]؉ and [Au(PPh3)]؉ with 3,5-
Bis(4-butoxyphenyl)pyrazole. Formation of [Pd(η3-C3H5)-
(HPzbp2)2](BF4) (4) and [Au(HPzbp2)(PPh3)](NO3) (5)
˚
Both pyrazole derivatives 4 and 5 (Scheme 2) were iso-
lated as stable, white solids, soluble in dichloromethane and
acetone. Elemental analysis, IR and 1H NMR spectroscopy
data agree with the proposed formulations.
Table 1. Selected bond lengths [A] and angles [°] for 4 with e.s.d.s.
in parentheses, including the hydrogen bond geometries
A
B
C
PdϪN1
PdϪN3
PdϪC9
PdϪC10
PdϪC11
C9ϪC10
C10ϪC11
N1ϪPdϪN3
N1ϪPdϪC9
N1ϪPdϪC10
N1ϪPdϪC11
N3ϪPdϪC11
N3ϪPdϪC9
N3ϪPdϪC10
C9ϪPdϪC10
2.10(2)
2.11(1)
2.10(1)
2.13(2)
2.15(2)
1.382(5)
1.377(5)
91.1(3)
98.8(6)
132.8(6)
167.1(6)
100.8(6)
170.0(6)
132.9(6)
38.2(3)
69.3(5)
37.6(3)
2.12(1)
2.12(1)
2.10(1)
2.10(1)
2.12(2)
1.384(5)
1.384(5)
93.4(4)
97.9(4)
130.3(4)
167.2(4)
99.3(4)
168.3(3)
132.7(4)
38.3(2)
69.3(3)
38.3(2)
2.12(1)
2.10(1)
2.10(1)
2.10(1)
2.12(2)
1.384(5)
1.386(5)
93.3(4)
100.0(4)
131.1(4)
169.3(4)
97.1(4)
166.1(4)
131.2(4)
38.7(2)
69.8(3)
38.4(2)
Scheme 2
Compound 4 was synthesised by treatment of the cationic
complex [Pd(η3-C3H5)(S)2]ϩ (S ϭ solvent), prepared in situ, C9ϪPdϪC11
C10ϪPdϪC11
Hydrogen bond geometries
DϪH···A
N2AϪH2A···F9Ј
N4AϪH4A···F2
N2BϪH2B···F7
N4BϪH4B···F1
N2CϪH2C···F11
N4CϪH4C···F5
with 3 in the same solvent in a 1:2 molar ratio. The IR
spectrum of 4 displays characteristic bands of the pyrazole
ligand. Between them, a ν(NH) absorption band at 3307
cmϪ1 was observed. This band was slightly shifted to higher
frequencies in relation to that of the free ligand (3229
cmϪ1), which has been shown to have a strong hydrogen
bond.[16] Related, but weaker, hydrogen bond interactions
are therefore suggested for 4 (it has been reported that HPz-
type ligands with free NH bonds present a ν(NH) absorp-
D···A
DϪH
0.86
0.86
0.86
0.86
0.86
0.86
H···A
1.97
2.06
2.19
1.99
1.91
2.01
DϪH···A
167.9
162.9
161.7
174.0
163.8
175.1
[a]
2.81(2)
2.89(1)
3.02(1)
2.81(1)
2.81(1)
2.81(1)
[a]
The atomic numbering as in Scheme 5.
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New Tris(pyrazolyl)triazine and Pyrazolylpyridine Gold(I) and Palladium(II) Derivatives
FULL PAPER
ratio between the integrated signals of aromatic PPh3 and
The palladium derivative 4 crystallises in the monoclinic
H4 pyrazole protons). In contrast to the behaviour ob- system, space group P21/n, as three [Pd(η3-
served for palladium derivative 4, complex 5 features two C3H5)(HPzbp2)2]ϩ species (A, B, and C, showing different
equivalent butoxyphenyl substituents, suggesting the pres- dihedral angles between phenyl and pyrazole groups) as-
Ϫ
ence of a metallotropic equilibrium as previously found for sociated through BF4 groups in the asymmetric unit (Fig-
Ϫ
related complexes.[20]
ure 1, top). Each BF4 group was bonded through strong
NϪH···F hydrogen bonds (Table 1) with two NϪH pyra-
zole groups bridging two neighbouring complexes. The ge-
ometry of each palladium() atom in A, B, and C can be
described as approximately square-planar. Two pyrazole li-
gands coordinate to each palladium() centre through the
corresponding unsubstituted pyrazole atoms N1 and N3,
Crystal and Molecular Structures of 4 and 5
Single crystals of 4 and 5 suitable for single-crystal X-ray
analysis were obtained after recrystallisation from dichloro-
methane/diethyl ether and dichloromethane/hexane, respec-
tively. Selected bond lengths and angles with their estimated
standard deviations are listed in Tables 1 and 2.
˚
with bond lengths in the 2.10Ϫ2.12 A range. The maximum
deviation of the allylic terminal atoms in these units A, B,
and C, if we define the coordination plane as that contain-
ing the palladium and the two nitrogen atoms mentioned,
˚
Table 2. Selected bond lengths [A] and angles [°] for 5 with e.s.d.s.
in parentheses, including the hydrogen bond geometries
˚
is 0.17(1) A for C9 in molecule A. The central allyl carbon
˚
N3ϪO5
N3ϪO3
N3ϪO4
Au1ϪN1
Au1ϪP1
P1ϪC32
P1ϪC26
P1ϪC38
Au1···O1Ј
N1ϪAu1ϪP1
O5ϪN3ϪO3
O5ϪN3ϪO4
O3ϪN3ϪO4
1.236(9)
1.245(8)
1.213(8)
2.077(5)
2.239(2)
1.800(8)
1.826(8)
1.822(7)
3.540(6)
C10 also deviates, by 0.51(9), 0.53(1), and 0.59(1) A in A,
B, and C, respectively. The dihedral angles between the allyl
planes C11C10C9 and C11PdC9 in each of the A, B, and
C molecules are 63.8(9), 67.4(8), and 66.6(8)°. The PdϪallyl
distances are in the range expected for complexes contain-
ing N,NЈ-ligands coordinated trans to palladium-allyl frag-
ment.[13c,21]
[a]
178.1(2)
The crystal structure of 4 could be defined as a pseudo-
helical polymer, consisting of [Pd(η3-C3H5)(HPzbp2)2]ϩ
117.9(8)
121.0(8)
121.2(7)
Ϫ
units bonding through BF4 anions as shown in Fig-
ure 1 (bottom). The F12 moiety of the third unit (C) is hy-
drogen-bonded to the NϪH pyrazole group of the neigh-
bouring AЈ molecule from the new asymmetric unit
Hydrogen bond geometries
DϪH···A
D···A
DϪH
0.95(6)
0.93
H···A
DϪH···A
N2ϪH2···O3
2.764(9)
3.382(9)
3.31(1)
1.82(7) 171(6)
C4ϪH4A···O4ЈЈ
C40ϪH40A···O5ЈЈЈ
2.63
2.88
137.3
115.1
(symmetry operation x, y,
z
ϩ
1). The [Pd(η3-
0.93
C3H5)(HPzbp2)2]ϩ moiety is thus arranged pseudohelically
[a]
R1 ϭΣ(|Fo| Ϫ |Fc|)/Σ|Fo|.
along the c axis, with the pitch of the pseudohelix (i.e., the
Figure 1. (top) Asymmetric unit of 4 with the atomic numbering scheme; (bottom) View of the helical distribution of 4 along c axis;
substituents on pyrazole in both pictures are omitted for clarity
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Figure 2. Molecular structure of 5 showing the dimeric unit through Au···O intermolecular bonds
distance between palladium() atoms of each four units)
The crystal structure of 5 (Figure 2) consists of a monon-
corresponding to the c axis. The molecular packing could uclear gold() cationic complex and a nitrate counter-ion.
be described as a columnar distribution of pseudohelical Both were bonded by
a
strong hydrogen bond
˚
chains lying along the c axis. The formation of this polymer (N2ϪH2···O3, with a N2···O3 distance of 2.764(9) A;
in the solid state demonstrates the important role played Table 2). The geometry around the gold() can be described
by intermolecular interactions through counter-ions in the as almost linear, the P1ϪAu1ϪN1 angle being 178.1(2)°.
supramolecular arrangements.
The Au1ϪN1 and Au1ϪP1 bond lengths are similar to
Figure 3. Molecular packing of 5 through c axis
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New Tris(pyrazolyl)triazine and Pyrazolylpyridine Gold(I) and Palladium(II) Derivatives
FULL PAPER
those reported for some neutral complexes of the absorption bands in the IR spectra of both compounds
[Au(L)(PPh3)] type (HL ϭ 1-methylthymine, 6-methylpyri- were not significantly modified in relation to that of the free
done, 7-azaindole).[22] The most interesting feature in 5 was ligand, indicating that the metal coordination had almost
the presence of a very weak intermolecular coordinative in- no effect on this bond, behaviour also observed for related
teraction [Au···O, at 3.540(6) A, ca. 0.30 A longer than the gold() derivatives containing N-heterocyclic ligands.[23]
˚
˚
Ϫ
Ϫ
sum of Van der Waals radii] between two neighbouring Characteristic bands of BF4 and NO3 anions were ob-
molecules. This interaction occurs through the oxygen atom served for 6 and 7, respectively.
1
of the C6H4OC4H9 substituent at the 5-position of the pyra-
The H NMR spectrum of 6 in CDCl3 at room tempera-
zole ligand and the metal centre of the adjacent molecule ture, in the allylic region, consisted of three broad signals:
and appears to be responsible for the formation of ‘‘dimers’’ a multiplet at δ ϭ 5.68 ppm, a doublet at δ ϭ 3.87 ppm
in an antiparallel head-to-tail disposition (Figure 2). The (J ϭ 6.5) Ϫ partially overlapping with that of the OCH2
adjacent aromatic rings of opposite substituents of each signal at δ ϭ 4.06 ppm Ϫ and a doublet at δ ϭ 3.21 ppm
molecule of ‘‘dimers’’ are parallel, but are separated face- (J ϭ 12.8) corresponding to the Hmeso, Hs, and Ha protons
˚
to-face by a distance of 4.4 A. This distance suggests that (the last of these clearly assigned from the observed coup-
π-π stacking interactions need not be considered, although ling constant). The broadness of the allyl signals suggests a
they might be of help in adopting the observed dimeric ar- fluxional behaviour based on the asymmetry of the N,NЈ-
rangement.
coordinated ligand and attributable to a rapid syn-syn and
The molecular packing could be described as a columnar anti-anti interchange. The remaining signals in the 1H
distribution of these dimeric units along the b axis. Layers NMR spectrum are assigned to the pyrazolylpyridine li-
almost orthogonal to the columnar axis defined by the sub- gand.
1
stituents on the pyrazole are also observed (Figure 3). New
The H NMR spectra of 7 was measured at room tem-
weak interactions through the O4 and O5 atoms of the perature in CD2Cl2. All the ligand proton signals were
Ϫ
NO3 group (not implicated in the hydrogen bond de- slightly modified by coordination. The general behaviour
scribed above) between dimeric units from neighbouring involves small shifts downfield for these signals, the largest
columns are also present (Table 2). As a consequence, the shifts being observed for the 3Ј-H and 5Ј-H pyridine pro-
effect of the counter-ion on the supramolecular assembly tons (Scheme 3). However, the position of 6Ј-H pyridine
again seems to be determinant for the crystalline structure proton was almost unchanged (δ ϭ 8.41 ppm for the free
here.
ligand and δ ϭ 8.38 ppm for the complex), suggesting a
very weak metal interaction towards the N-pyridine atom.
On the other hand, the 4-H pyrazole proton shows a down-
field coordination shift of δ ϭ 0.12 ppm, and both down-
field and upfield effects were observed for the phenyl sub-
stituents in positions 3 and 5. Related behaviour has also
been observed for copper and ruthenium derivatives con-
taining pyrazolylpyridine-type ligands.[24,25] The downfield
shifts occurring for pyrazole protons and substituents on
the 4- and 5-positions were attributed to ligand-metal coor-
dination, whereas upfield shifts for substituents on the 3-
position were attributed to ring current anisotropy effects.
The above 1H NMR results agree with a monodentate coor-
dination of the ligand towards the pyrazole N atom, al-
lowing the characteristic twofold coordination of gold me-
tal centres. In this context it should be pointed out that tri-
and tetracoordinate gold() derivatives with PPh3 and N-
donor ligands have also been described, although less fre-
quently,[26] and so an interaction with the pyridine N atom
should not be excluded for complex 7. However, the well
defined signals observed for all the protons suggest that ex-
change of gold() between the two nitrogen coordination
sites does not occur at room temperature. This fact, prob-
ably due to steric effects of substituents on the pyrazole
group, favours the linear complex.
Treatment of [Pd(η3-C3H5)]؉ and [Au(PPh3)]؉ with
2-[3,5-Bis(4-butoxyphenyl)pyrazol-1-yl]pyridine.
Formation of [Pd(η3-C3H5)(Pzbp2Py)](BF4) (6) and
[Au(Pzbp2Py)(PPh3)](NO3) (7)
Compounds 6 and 7 (Scheme 3) were both isolated as
stable yellow solids, soluble in dichloromethane and ace-
tone, as described in the Exp. Sect. Elemental analysis and
IR and H and 13C NMR spectroscopy data agree with the
1
proposed formulations. Conductivity measurements in ace-
tone solution are consistent with 1:1 electrolytic behaviour
in both cases.
Scheme 3
On addition of an equivalent of
2
to [Pd(η3-
On close examination of the 13C NMR spectroscopic
C3H5)(S)2](BF4), the ionic complex 6 is formed. The gold() data and after complete assignment of all signals by means
complex 7 was prepared by starting from cleavage of the of NMR experiments with pulse field gradients — (1H-1H)
chloride in [AuCl(PPh3)] by addition of AgNO3, giving rise COSY, (1H-13C) HMQC, and (1H-13C) HMBC — it can
to [Au(NO3)(PPh3)], and the subsequent replacement of the be concluded that the complexation chemical shift effects
Ϫ
NO3 group by the N,NЈ-bidentate ligand 2. The ν(CϭN) (CCSEs) in the palladium() and gold() complexes 6 and
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M. Cano et al.
FULL PAPER
7 are positive, save for the carbon adjacent to the pyridine respectively. The gold() derivative was isolated from treat-
nitrogen, which bonds the pyrazole group. Such increments ment of three equivalents of [Au(NO3)(PPh3)] with one of
are larger in the palladium complex 6 (around 4 ppm) than 1 in dichloromethane solution as a yellow solid product,
in the gold complex 7 (around 2 ppm).
stable enough in solution for NMR purposes. It was charac-
In order to establish more conclusive results regarding terized as the complex [Au3(TPzbp2Tz)(PPh3)3](NO3)3 (9,
the metal ligand coordination, 15N NMR studies were car- Scheme 4) on the basis of its H NMR spectroscopic and
1
ried out by means of (1H-15N) HMBC experiments on the mass spectrometric data.
ligand and the palladium() and gold() derivatives
On the other hand, it was interesting to note that a side
product, in the form of a microcrystalline white solid ac-
Table 3. 15N NMR spectroscopic data (in CDCl3 at 298 K) for the companying the main compound 9, was also isolated from
free ligand 2and its Pd(η3-C3H5) (6) and Au(PPh3) (7) derivatives
the reaction. Treatment of this mixture in dichloromethane/
diethyl ether allowed crystals of this by-product to be sepa-
rated, and these were identified as the pyrazolate complex
[Au2(µ-Pzbp2)(PPh3)2](NO3).[10b]
The IR spectrum of 9 shows the main absorption bands
of the TPzbp2Tz ligand. A very weak unexpected band was
also observed at 1682 cmϪ1, and was attributed to a ν(Cϭ
O) absorption arising from partial hydrolysis of the
Pyrazole
N1
Pyridine
N3
TPzbp2Tz ligand in the complex. This band increases after
repeated attempts to purify the product confirming that the
hydrolysis process is enhanced.
N2
Ϫ84.9
Ϫ136.8
Ϫ104.1
2
Ϫ166.4
Ϫ167.9
Ϫ168.0
Ϫ84.0
Ϫ151.0
Ϫ88.0
The structural 1H NMR spectroscopic data, in relation to
those obtained for [Au(Pzbp2Py)(PPh3)](NO3) (7), suggest
monodentate N-pyrazole coordination towards the
Au(PPh3) fragment. The tris(pyrazoly)ltriazine ligand
bridges three metal centres coordinated with three N-pyra-
zole atoms from the three asymmetric N,NЈ-chelating sites.
The 15:1 relationship between the aromatic PPh3 and the 4-
H pyrazole protons agrees with the proposed formulation.
A relevant aspect of the molecular behaviour observed at
room temperature is the effect that the metals induce on the
pyrazole substituents, those in the proximity of Au(PPh3)
fragment (3-position) being different to those at the 5-posi-
tion. The former thus show defined signals for all protons
of the chains but the related signals for the latter are broad.
This behaviour is consistent with the proposed monodent-
ate coordination of gold() centres only towards the pyra-
zole groups. Rotation of the pyrazole group bonded to the
Au(PPh3) fragment around the pyrazole-triazine bonding
axis is possible, and the environment of the substituents on
the 3-position close to the Au(PPh3) fragment is not modi-
fied, unlike that of 5-position substituents, which change in
their spatial proximity to gold metal centres.
6
7[a]
[a] 15N NMR data in CD2Cl2.
(Table 3). For the palladium complex 6 it was clearly ob-
served that coordinative nitrogen atoms, N2 from pyrazole
and N3 from pyridine, were significantly shifted upon coor-
dination relative to the free ligand. For gold derivative 7, in
contrast, such an effect was only produced on the pyrazole
nitrogen atom N2. Consequently, an N,NЈ-bidentate pyr-
azolylpyridine coordinative mode was proposed for the pal-
ladium derivative but only a monodentate coordination in-
volving the pyrazole group for the gold complex 7. Both
results also agree with the expected tetracoordinate square-
planar and two-coordinate linear environments around the
palladium() and gold() metal centres, respectively.
Treatment of [Pd(η3-C3H5)]؉ and [Au(PPh3)]؉ with 2,4,6-
Tris[3,5-bis(4-butoxyphenyl)pyrazol-1-yl]-1,3,5-triazine.
Formation of [Pd2(η3-C3H5)2(BPzbp2TzO)](BF4) (8) and
[Au3(TPzbp2Tz)(PPh3)3](NO3)3 (9)
Treatment of 1 with [Pd(η3-C3H5)]ϩ or [Au(PPh3)]ϩ frag-
ments resulted in bimetallic and trimetallic complexes,
To confirm the proposed trimetallic formulation of 9, a
study by mass spectrometry (FAB and ESI) was carried out.
Figure 4 displays a fragmentation scheme for this complex.
The parent ion was not observed either by FAB or by ESI
(dry acetonitrile and chloroform) mass spectra. In contrast,
in all the cases mentioned above, two ion peaks at m/z ϭ
2444.7 and 1277.2 were detected. The former (m/z ϭ
2444.7) corresponds to the [TPzbp2Tz ϩ B]ϩ fragment (a1)
arising from the association of the TPzbp2Tz ligand with a
metallic cluster B {B ϭ [Au2(PPh3)NO3(OH)2]}. From this
fragment, the second ion peak (m/z ϭ 1277.2) is formed by
the loss of TPzbp2Tz. On the other hand, the ESI spectrum
(in dry acetonitrile) shows a new peak at m/z ϭ 867.7 (0.3
mass units separated from their counterparts) for the tric-
ation [{Au3(TPzbp2Tz)(PPh3)3(NO3)} Ϫ 2 H]3ϩ (a3) (calcd.
Scheme 4
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New Tris(pyrazolyl)triazine and Pyrazolylpyridine Gold(I) and Palladium(II) Derivatives
FULL PAPER
Figure 4. Fragmentation scheme for the complex [Au3(TPzbp2Tz)(PPh3)3](NO3)3 9; symbols (a), (b), and (c) indicate: (a) fragments contain-
ing the TPzbp2Tz ligand, (b) fragments containing the hydrolysed TPzbp2Tz ligand (BPzbp2TzO), and (c) side product
2605). Another fragment, observed in all spectra, at m/z ϭ
Several attempts to crystallise 9 from different solvents
1627.5 was related to the mononuclear species were carried out, but hydrolysis products prevent the obten-
[Au(TPzbp2Tz)(PPh3)]ϩ (a2). The above results agree with tion of crystals suitable for X-ray purposes.
the presence of a TPzbp2Tz ligand in a trimetallic species.
Similar results were also obtained for the related complex
On the other hand, additional ion peaks at m/z ϭ 1738.6 [Au3(TPzbp2Tz)(PPh3)3](CF3SO3)3
(10),
containing
Ϫ
and 1281.3 were also observed and related to a hydrolysis CF3SO3 as counter-ion.
process of the TPzbp2Tz ligand, producing binuclear
The binuclear complex [Pd2(η3-C3H5)2(BPzbp2TzO)]-
[Au2(BPzbp2TzO)(PPh3)2]ϩ
(b1)
and
mononuclear (BF4) (8) was obtained by treatment of 1 with [Pd(η3-
[{Au(BPzbp2TzO)(PPh3)} ϩ H]ϩ (b2) species, respectively. C3H5)(S)2]ϩ in a 1:3 molar ratio. The suggested molecular
These were the sole peaks observed when the ESI spectrum structure (Scheme 5) was defined by bonding two [Pd(η3-
was recorded in solvents favouring hydrolysis, such as meth- C3H5)]ϩ fragments bound in two bidentate positions of the
anol. Finally, the presence of the side product formulated hydrolysed tris(pyrazolyl)triazine ligand BPzbp2TzO, which
as [(PPh3)Au(µ-Pzbp2)Au(PPh3)]ϩ (c) at m/z ϭ 1280.5 was has lost a pyrazolyl group. A related hydrolysis product has
also evidenced, in agreement with the isolation of that com- precedent in the described cationic complex [{(η3-2-
pound from the reaction.
MeϪC3H4)Pd}2(MeϪBPzTO)]ϩ,[21] and also in the estab-
Eur. J. Inorg. Chem. 2003, 2693Ϫ2704
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2699

M. Cano et al.
FULL PAPER
Scheme 5
lished nucleophilic displacement reactions of some 1,3,5-
triazines.[27] This was the sole metal derivative isolated from
the above reaction. It was interesting to note, though, that
the first solid to separate from the reaction mixture was a
white crystalline product, identified as the pyrazolium salt
[H2Pzbp2](BF4) 11 (see Exp. Sect.).
Conclusion
The designed complexes [Pd(η3-C3H5)(HPzbp2)2](BF4) (4)
and [Au(HPzbp2)(PPh3)](NO3) (5) each show strong hydro-
gen bonding between each NH-pyrazole of one cationic
unit and their corresponding counter-ions. In view of the
molecular geometries around the metal centres Ϫ square-
planar for the palladium derivative and linear for gold Ϫ
as well as those of their counter-ions, tetrahedral BF4Ϫ and
planar NO3Ϫ, these hydrogen bonds Ϫ NϪH···F for 4 and
N2ϪH2···O3, C4ϪH4A···O4ЈЈ and C40ϪH40A···O5ЈЈЈ for
5 — are responsible for the observed supramolecular struc-
tures, of the pseudohelical type for 4 and with columnar
features for 5. In addition, 5 forms ‘‘dimers’’ produced by
coordinative Au···O interactions between the pyrazole OR
groups and the metal centres of two neighbouring mol-
ecules. We can therefore conclude that factors such as hy-
drogen bonding, the counter-ion effect, the presence of co-
ordinating substituents on the ligand and a suitable molecu-
lar geometry are crucial for specific supramolecular as-
semblies.
The IR spectrum of 8 shows the characteristic bands due
1
to the ν(CϭO) absorption at 1696 cmϪ1 and the H NMR
spectrum present all the expected pyrazolyl signals as well
as the 1:1 ratio of H4 pyrazole and Hmeso allyl protons.
From the analysis of the 13C NMR spectroscopic data
and having assigned all signals by means of NMR experi-
ments with pulse field gradients — (1H-1H) COSY, (1H-13C)
HMQC and (1H-13C) HMBC — we observed that the
CCSE signs for complexes 8 and 9 are similar, but that the
absolute values of 9 are approximately half those of 8.
The appearance of the additional carbonyl signal in the
spectrum of the palladium() complex 8 confirms the hy-
drolysis process.
The 15N NMR spectroscopic data obtained from (1H-
15N) HMBC correlation experiments for the free TPzbp2Tz
ligand 1 and the palladium complex 8 are presented in
Table 4. As in the previous [Pd(η3-C3H5)(Pzbp2Py)](BF4)
complex 6, the observed chemical shift effects on the pal-
ladium derivative in relation to the free ligand agree with a
bidentate coordination by N-pyrazole and N-triazine coord-
inating nitrogen atoms and confirm the proposed formu-
lation.
Moreover, the following structural features should be
pointed out:
i) The palladium complex of TPzbp2Tz is hydrolysed,
giving
rise
to
a
bimetallic
species
[Pd2(η3-
C3H5)2(BPzbp2TzO)](BF4) (8), containing two allyl-pal-
ladium moieties, which occupy two symmetrical N,NЈ-bi-
dentate chelating positions of the ligand. The central car-
bon atom of the triazine core is now bonded to an oxygen,
thus producing a CϭO group instead of the initial C-Pzbp2
one, due to the nucleophilic displacement of the pyrazole
group in the hydrolysis process.
Table 4. 15N NMR spectroscopic data in CDCl3 at 298 K of the
free ligand 1 and its Pd(η3-C3H5) derivative 8
ii) The formation of
a
trimetallic derivative
Pyrazole[a]
N1
Triazine[a]
N3
[Au3(TPzbp2Tz)(PPh3)3](NO3)3 (9), containing three
Au(PPh3) fragments coordinated in a monodentate fashion
towards the N-pyrazole atoms of the TPzbp2Tz ligand, has
been established.
N2
N4
1
8
Ϫ169.3
Ϫ170.2
Ϫ86.0
Ϫ138.8
Ϫ156.8
Ϫ123.8
Ϫ156.8
Ϫ197.4
The natures of the metal fragments determine the mono-
or bidentate coordination of each N,NЈ-chelating position
in the TPzbp2Tz, analogously to what occurs in similar com-
[a]
The atomic numbering as in Scheme 5.
Finally, the ESI mass spectrum (in chloroform) of 8 plexes of the related bidentate Pzbp2Py ligand. The presence
shows the molecular ion peak m/z ϭ 1116.3 confirming the of a square-planar or more flexible linear metal environ-
formation of the hydrolysis derivative [Pd2(η3- ments for 8 and 9, respectively, appears to be correlated
C3H5)2(BPzbp2TzO)](BF4).
with the isolation of a binuclear palladium complex or a
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New Tris(pyrazolyl)triazine and Pyrazolylpyridine Gold(I) and Palladium(II) Derivatives
FULL PAPER
(1J ϭ 126.3 Hz, CH2), 19.2 and 19.1 (1J ϭ 127.2 Hz, CH2), 13.79
trinuclear gold derivative. These results offer new insights
into the attainment of polymetallic complexes with supra-
molecular organisations.
and 13.77 (1J ϭ 125.3 Hz, CH3).
Synthesis of [Pd(η3-C3H5)(HPzbp2)2](BF4) (4): AgBF4 (35 mg,
0.18 mmol) was added under nitrogen to a solution of [Pd(η3-
C3H5)(µ-Cl)]2 (33 mg, 0.09 mmol) in freshly distilled acetone
(15 mL). After stirring for 6 h in the darkness, the solution was
filtered through a plug of Celite and cooled with an ice bath. Com-
pound 3 (HPzbp2, 131 mg, 0.36 mmol) was then added and the mix-
ture was stirred for 5 h. The solvent was removed under vacuum
and the white product was crystallised from dichloromethane/di-
ethyl ether. Yield: 73 mg, 42%. C49H61BF4N4O4Pd (962.21): calcd.
C 61.11, H 6.34, N 5.82; found C 60.96, H 6.11, N 5.66. IR (KBr):
Experimental Section
Materials and Instrumentation: The commercial starting materials
[Pd(η3-C3H5)(µ-Cl)]2 and [AuCl(PPh3)] were used as supplied.
Ligands
2-[3,5-bis(4-butoxyphenyl)pyrazol-1-yl]pyridine
(2,
Pzbp2Py)[24] and 3,5-bis(4-butoxyphenyl)pyrazole (3, HPzbp2 [16]
)
were prepared as described in the literature. Commercial solvents
were dried prior to use.
Ϫ1
1
˜
ν ϭ 3307 cm ν(NϪH), 1613 ν(CϭN), 1067 and 1039 ν(BF). H
NMR (400 MHz, CDCl3, 298 K): δ ϭ 11.87 ppm (s, 2 H, NH),
7.61 and 7.41 (d, 3J ϭ 8.5 Hz, 8 H, Ho), 6.96 and 6.78 (d, 3J ϭ
Melting points were determined on a microscope hot stage appar-
atus and are uncorrected.
8.5 Hz, 8 H, Hm), 6.54 (s, 2 H, H4), 5.70 (m, 3Js ϭ 6.8, 3Ja
12.7 Hz, 1 H, Hmeso), 3.99 and 3.94 (t, J ϭ 6.6 Hz, 8 H, OCH2),
3.92 (d, Js ϭ 6.8 Hz, 2 H, Hs), 3.18 (d, Ja ϭ 12.7 Hz, 2 H, Ha),
1.87Ϫ1.70 (m, 8 H, CH2), 1.64Ϫ1.40 (m, 8 H, CH2), 1.00 and 0.98
(t, J ϭ 7.3 Hz, 12 H, CH3).
ϭ
3
Elemental analyses for carbon, hydrogen, and nitrogen were carried
out by the Microanalytical Service of the Complutense University.
IR spectra were performed on a FTIR Nicolet Magna-550 spectro-
photometer in the 4000Ϫ400 cmϪ1 region with samples as KBr pel-
lets.
3
3
3
Synthesis of [Au(HPzbp2)(PPh3)](NO3) (5): AgNO3 (34 mg,
0.20 mmol) was added under nitrogen to a solution of [AuCl(PPh3)]
(100 mg, 0.20 mmol) in acetone (25 mL). After stirring for 2 h in
darkness, the solution was filtered through a plug of Celite and the
solvent was evaporated. Compound 3 (HPzbp2, 73 mg, 0.20 mmol)
was added to a solution of the obtained product in dry dichloro-
methane and the mixture was stirred for 5 h at room temperature.
The solvent was removed under vacuum to provide a oil, from
which a white solid was isolated by addition of dichloromethane
and hexane. This solid was crystallised from dichloromethane/hex-
ane. Yield: 90 mg, 51%. C41H43N3O5AuP (884.94): calcd. C 55.60,
H 4.86, N 4.75; found C 55.82, H 4.73, N 4.88. IR (KBr): ν˜ ϭ 3250
cmϪ1 ν(NϪH), 1613 ν(CϭN), 1384 νas(NO3). 1H NMR (400 MHz,
CDCl3, 298 K): δ ϭ 7.78 ppm (d, 3J ϭ 8.8 Hz, 4 H, Ho), 7.57Ϫ7.40
(m, 15 H, PPh3), 6.92 (d, 3J ϭ 8.8 Hz, 4 H, Hm), 6.71 (s, 1 H, H4),
1H, 13C, and 15N NMR spectra were recorded on a Bruker DRX-
400 at 27 °C. Chemical shifts (δ) are given in ppm from TMS for
1H and 13C NMR spectroscopy. 15N NMR chemical shifts were
1
obtained by the Inverse Gated H-Decoupling Technique and are
referenced to external nitromethane. J coupling constants are in
Hz. The assignments are based on NMR experiments with pulse
field gradients: (1H-1H) COSY, (1H-13C) HMQC, (1H-13C) HMBC,
and (1H-15N) HMBC.[28]
FAB-MS positive spectra were performed on a VG AutoSpec spec-
trometer. ESI-MS positive spectra were carried out by the Mass
Spectrometry Service of the Complutense University with a LC-
SQUIRE spectrometer, in dry acetonitrile, chloroform, or meth-
anol as solvents. The ion peaks are given in m/z.
3
3.97 (t, J ϭ 6.6 Hz, 4 H, OCH2), 1.78 (m, 4 H, CH2), 1.49 (m, 4
3
Synthesis of 2,4,6-Tris[3,5-bis(4-butoxyphenyl)pyrazol-1-yl]-1,3,5-
H, CH2), 0.99 (t, J ϭ 7.3 Hz, 6 H, CH3).
triazine (TPzbp2Tz, 1): NaH (95%, 44 mg, 1.74 mmol) was added
to
a
solution of 3,5-bis(4-butoxyphenyl)pyrazole (3, 600 mg,
Synthesis of [Pd(η3-C3H5)(Pzbp2Py)](BF4) (6): This compound was
prepared in a similar way to 4, from [Pd(η3-C3H5)(µ-Cl)]2 (110 mg,
0.30 mmol), AgBF4 (117 mg, 0.60 mmol), and 2 (Pzbp2Py) (265 mg,
1.65 mmol) in freshly distilled dry THF (30 mL). After 1.5 h at 90
°C, the solution was allowed to cool down, and 2,4,6-trichlorotriaz-
ine (cyanuric chloride, 90%, 102 mg, 0.55 mmol) was added. The 0.60 mmol). White crystals were obtained by crystallisation from
solution, which had turned from a yellow to a white colour, was dichloromethane/hexane. Yield: 215 mg, 53%. C31H36BF4N3O2Pd
heated for 11 h at 90 °C and for 15 h at 60 °C. The solvent was (675.21): calcd. C 55.09, H 5.33, N 6.22; found C 54.75, H 5.30, N
evaporated and the residue was chromatographed on 60 F254 silica
6.21. IR (KBr): ν˜ ϭ 1609 and 1571 cmϪ1 ν(CϭN), 1069 and 1027
ν(BF). H NMR (400 MHz, CDCl3, 298 K): δ ϭ 8.85 ppm (m, 1
1
gel with chloroform/acetonitrile (95:5) as eluent. Rf ϭ 0.55, m.p.
158Ϫ160 °C. Yield: 193 mg, 30%. Exact mass: calcd. for H, H6Ј), 7.81 (ddd, 3J ϭ 8.6, 3J ϭ 7.3, 4J ϭ 1.6 Hz, 1 H, H4Ј),
C72H81N9O6: 1168.49; found 1168.63. IR (KBr): ν˜ ϭ 1613 cmϪ1 7.58 (d, J ϭ 8.6 Hz, 2 H, Ho), 7.53 (m, 1 H, H5Ј), 7.39 (d, J ϭ
3
3
1
ν(CϭN). H NMR (400 MHz, CDCl3, 298 K): δ ϭ 7.76 ppm (d, 8.5 Hz, 2 H, Ho), 7.06 (d, 3J ϭ 8.5 Hz, 2 H, Hm), 7.04 (d, 3J ϭ
3J ϭ 6.9 Hz, 6 H, Ho), 7.24 (d, 3J ϭ 6.8 Hz, 6 H, Ho), 6.98 (d, 3J ϭ
6.9 Hz, 6 H, Hm), 6.85 (d, 3J ϭ 6.8 Hz, 6 H, Hm), 6.63 (s, 3 H, H4),
8.6 Hz, 2 H, Hm), 6.99 (d, 3J ϭ 8.6 Hz, 1 H, H3Ј), 6.70 (s, 1 H,
3
3
3
H4), 5.68 (m, Js ϭ 6.5, Ja ϭ 12.8 Hz, 1 H, Hmeso), 4.06 (t, J ϭ
4.04 (t, 3J ϭ 6.5 Hz, 6 H, OCH2), 3.87 (t, 3J ϭ 6.6 Hz, 6 H, OCH2), 6.5 Hz, 4 H, OCH2), 3.87 (d, 3Js ϭ 6.5 Hz, 2 H, Hs), 3.21 (d, 3Ja ϭ
3
1.82 (m, J ϭ 6.7 Hz, 6 H, CH2), 1.72 (m, 3J ϭ 6.8 Hz, 6 H, CH2), 12.8 Hz, 2 H, Ha), 1.82 (m, 4 H, CH2), 1.54 (m, 4 H, CH2), 1.01
3
3
1.51 (m, J ϭ 7.4 Hz, 6 H, CH2), 1.43 (m, 3J ϭ 7.5 Hz, 6 H, CH2), (t, J ϭ 7.4 Hz, 6 H, CH3). 13C NMR (400 MHz, CDCl3, 298 K):
1.01 and 0.94 (t, 3J ϭ 7.4 Hz, 18 H, CH3). 13C NMR (400 MHz, δ ϭ 161.3 and 161.2 ppm (Cp), 157.4 (3J ϭ 3J ϭ 4.6 Hz, C3), 153.8
CDCl3, 298 K): δ ϭ 164.5 ppm (Tz), 159.9 (3J ϭ 3J ϭ 7.6 Hz, Cp),
(1J ϭ 187.7 Hz, C6Ј), 149.7 (C2Ј), 147.1 (2J ϭ 8.8, 3J ϭ 3J ϭ
5.0 Hz, C5), 141.2 (1J ϭ 167.6 Hz, C4Ј), 130.4 (1J ϭ 160.5, 3J ϭ
3
3
3
159.2 (3J ϭ J ϭ 9.2 Hz, Cp), 154.3 (2J ϭ J ϭ J ϭ 3.7 Hz, C3),
147.8 (2J ϭ 8.1, 3J ϭ 3J ϭ 4.0 Hz, C5), 130.2 (1J ϭ 160.3, 3J ϭ 7.5 Hz, Co), 130.1 (1J ϭ 160.2, 3J ϭ 7.3 Hz, Co), 124.5 (1J ϭ
7.1 Hz, Co), 127.7 (1J ϭ 159.5, J ϭ 7.0 Hz, Co), 124.1 (3J ϭ J ϭ
170.3 Hz, C5Ј), 122.9 (3J ϭ J ϭ 7.8 Hz, Cipso), 119.7 (3J ϭ J ϭ
3
3
3
3
7.6 Hz, Cipso), 123.1 (3J ϭ J ϭ 8.0 Hz, Cipso), 114.5 (1J ϭ 160.2, 7.7 Hz, Cipso), 117.4 (1J ϭ 164.6 Hz, CH allyl), 115.7 (1J ϭ 161.8,
3
3J ϭ 4.6 Hz, Cm), 113.9 (1J ϭ 160.5, 3J ϭ 4.2 Hz, Cm), 109.4 (1J ϭ
3J ϭ 4.7 Hz, Cm), 114.7 (1J ϭ 161.2, 3J ϭ 4.5 Hz, Cm), 114.6 (C3Ј),
175.5 Hz, C4), 67.6 (1J ϭ 142.1, 2J ϭ 3.5 Hz, OCH2), 31.3 and 31.2 111.3 (1J ϭ 181.7 Hz, C4), 68.1 (1J ϭ 142.7 Hz, OCH2), 63.6 (CH2
Eur. J. Inorg. Chem. 2003, 2693Ϫ2704
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M. Cano et al.
FULL PAPER
3
allyl), 31.2 (1J ϭ 126.5 Hz, CH2), 19.2 (1J ϭ 127.5 Hz, CH2), 13.8
7.3Ϫ7.5 (br., 6 H, Ho), 7.02 (br., 6 H, Hm), 6.92 (d, J ϭ 6.8 Hz, 6
(1J ϭ 125.0 Hz, CH3).
H, Hm), 6.83 (s, 3 H, H4), 4.00 (t, J ϭ 6.5 Hz, 6 H, OCH2), 3.94
(br., 6 H, OCH2), 1.80 (m, J ϭ 7.0 Hz, 6 H, CH2), 1.75 (br., 6 H,
3
3
Synthesis of [Au(Pzbp2Py)(PPh3)](NO3) (7): Compound 7 was pre-
pared similarly to 5, from [AuCl(PPh3)] (80 mg, 0.16 mmol),
AgNO3 (27 mg, 0.16 mmol), and 2 (Pzbp2Py) (71 mg, 0.16 mmol).
The obtained yellow solid was purified by treatment with dichloro-
methane. Yield: 74 mg, 48%. C46H46AuN4O5P (961.94): calcd. C
57.38, H 4.78, N 5.82; found C 57.48, H 4.90, N 5.62. IR (KBr):
ν˜ ϭ 1611 and 1576 cmϪ1 ν(CϭN), 1357 νas(NO3). 1H NMR
(400 MHz, CD2Cl2, 298 K): δ ϭ 8.38 ppm (m, 1 H, H6Ј), 7.87 (d,
CH2), 1.54 (m, 3J ϭ 7.5 Hz, 6 H, CH2), 1.49 (br., 6 H, CH2), 1.01 (t,
3J ϭ 7.4 Hz, 9 H, CH3), 0.98 (br., 9 H, CH3). 13C NMR (400 MHz,
CD2Cl2, 298 K): δ ϭ 162.1 ppm (br., Tz), 160.9 (Cp), 156.5 (br.,
Cp), 154.8 (C3), 149.1 (br., C5), 135Ϫ130 (PPh3), 129.7 (Co), 128.9
(br., Co), 124.9 (Cipso), 122.1 (br., Cipso), 115.7 (Cm), 115.1 (br., Cm),
112.1 (br., C4), 68.7 (OCH2), 32.00 and 31.98 (CH2), 20.04 and
19.97 (CH2), 14.4 (CH3).
3J ϭ 8.8 Hz, 2 H, Ho), 7.82 (ddd, J ϭ 8.1, J ϭ 7.5, J ϭ 1.6 Hz,
1 H, H4Ј), 7.54Ϫ7.41 (m, 15 H, PPh3), 7.40 (m, 1 H, H5Ј), 7.35 (d,
3J ϭ 8.1 Hz, 1 H, H3Ј), 7.25 (d, 3J ϭ 8.8 Hz, 2 H, Ho), 6.91 (d,
3
3
4
Treatment of TPzbp2Tz with [Au(CF3SO3)(PPh3)]. Formation of
[Au3(TPzbp2Pz)(PPh3)3](CF3SO3)3 (10): AgCF3SO3 (54 mg,
0.21 mmol) was added under nitrogen to a solution of [AuCl(PPh3)]
(102 mg, 0.21 mmol) in dry THF (25 mL). After stirring for 2 h in
the darkness, the solution was filtered through a plug of Celite.
Compound 1 (TPzbp2Tz, 80 mg, 0.07 mmol) was then added and
the mixture was stirred for 4 h at room temperature. The solvent
was removed under vacuum to afford an oil, from which a yellow
solid was isolated by addition of diethyl ether and hexane. This
solid was purified by treatment with dichloromethane. Yield:
119 mg, 57%. C129H126Au3F9N9O15P3S3 (2990.82): calcd. C 51.76,
H 4.21, N 4.21; found C 52.03, H 4.28, N 4.25.
3J ϭ 8.8 Hz, 4 H, Hm), 6.83 (s, 1 H, H4), 4.00 (t, J ϭ 6.5 Hz, 4
3
3
H, OCH2), 1.78 (m, 4 H, CH2), 1.51 (m, 4 H, CH2), 1.00 (t, J ϭ
7.4 Hz, 6 H, CH3). 13C NMR (400 MHz, CD2Cl2, 298 K): δ ϭ
161.1 and 161.0 ppm (Cp), 154.9 (3J ϭ 3J ϭ 4.1 Hz, C3), 151.7
(C2Ј), 149.8 (1J ϭ 182.9, J ϭ 7.2 Hz, C6Ј), 147.4 (2J ϭ 7.3, J ϭ
3J ϭ 3.7 Hz, C5), 140.1 (1J ϭ 166.1 Hz, C4Ј), 135Ϫ130 (PPh3),
130.9 (1J ϭ 159.9, 3J ϭ 7.3 Hz, Co), 129.1 (1J ϭ 159.4, 3J ϭ 7.4 Hz,
3
3
Co), 124.7 (1J ϭ 167.0 Hz, C5Ј), 124.4 (3J ϭ J ϭ 8.0 Hz or J ϭ
3
3
3J ϭ 7.7 Hz, Cipso), 121.9 (3J ϭ J ϭ 8.0 Hz or J ϭ J ϭ 7.7 Hz,
3
3
3
Cipso), 120.9 (1J ϭ 175.2 Hz, C3Ј), 115.6 (1J ϭ 160.8 Hz or 1J ϭ
159.7, J ϭ 4.3 Hz, Cm), 115.5 (1J ϭ 160.8 Hz or J ϭ 159.7, J ϭ Synthesis of [H2Pzbp2](BF4) (11): HBF4Ϫdiethyl ether complex
3
1
3
4.3 Hz, Cm), 107.7 (1J ϭ 178.5 Hz, C4), 68.7 (1J ϭ 143.6 Hz,
(85%, 37 mg, 0.36 mmol) was added to a solution of 3 (HPzbp2
,
OCH2), 32.0 (1J ϭ 125.3 Hz, CH2), 20.0 (1J ϭ 126.2 Hz, CH2), 131 mg, 0.36 mmol) in diethyl ether (5 mL) and the mixture was
14.4 (1J ϭ 124.7 Hz, CH3).
stirred for 1 h at room temperature. A white crystalline precipitate
was filtered off and washed with diethyl ether. Yield: 73 mg, 45%.
IR (KBr): ν˜ ϭ 3238 and 3178 cmϪ1 ν(NϪH), 1619 ν(CϭN), 1067
Synthesis of [Pd2(η3-C3H5)2(BPzbp2TzO)](BF4) (8): The synthetic
procedure used for 8 was similar to that described for 4, from
[Pd(η3-C3H5)(µ-Cl)]2 (21 mg, 0.06 mmol), AgBF4 (23 mg,
0.12 mmol), and 1 (TPzbp2Tz) (46 mg, 0.04 mmol). The resulting
yellow solid was purified by crystallisation in dichloromethane/hex-
ane. Yield: 36 mg, 75%. C55H64BF4N7O5Pd2 (1201.61): calcd. C
54.93, H 5.33, N 8.15; found C 55.00, H 5.66, N 8.00. IR (KBr):
ν˜ ϭ 1696 cmϪ1 ν(CϭO), 1611 ν(CϭN), 1066 ν(BF). 1H NMR
(400 MHz, CDCl3, 298 K): δ ϭ 7.59 and 6.99 ppm (d, 3J ϭ 6.8 Hz,
1
ν(BF). H NMR (400 MHz, CDCl3, 298 K): δ ϭ 13.2 ppm (br., 2
H, NH), 7.67 (d, 3J ϭ 8.5 Hz, 4 H, Ho), 7.03 (d, 3J ϭ 8.5 Hz, 4 H,
3
Hm), 6.86 (s, 1 H, H4), 4.02 (t, J ϭ 6.6 Hz, 4 H, OCH2), 1.80 (m,
4 H, CH2), 1.51 (m, 4 H, CH2), 0.99 (t, J ϭ 7.3 Hz, 6 H, CH3).
3
X-ray Structure Determination
Prismatic single crystals of [Pd(η3-C3H5)(HPzbp2)2](BF4) (4) were
8 H, Ho), 7.03 and 6.62 (d, 3J ϭ 6.8 Hz, 8 H, Hm), 6.52 (s, 2 H, obtained by crystallisation from dichloromethane/diethyl ether.
3
3
3
H4), 5.44 (m, Js ϭ 6.5, Ja ϭ 13.0 Hz, 2 H, Hmeso), 4.05 (t, J ϭ
Single needle crystals of [Au(HPzbp2)(PPh3)](NO3) (5) were ob-
3
6.5 Hz, 4 H, OCH2), 3.99 (t, J ϭ 6.4 Hz, 4 H, OCH2), 3.79 (br., tained by crystallisation from dichloromethane/hexane.
3Js ϭ 6.5 Hz, 4 H, Hs), 3.21 (br., 3Ja ϭ 13.0 Hz, 4 H, Ha), 1.80 (m,
3
The data for both compounds were collected on a Smart Bruker
CCD detector diffractometer. A summary of the fundamental crys-
tal data and refinement parameters for the two crystals is given
in Table 5.
8 H, CH2), 1.53 (m, 8 H, CH2), 1.00 and 0.99 (t, J ϭ 7.5 Hz, 12
H, CH3). 13C NMR (400 MHz, CDCl3, 298 K): δ ϭ 163.1 ppm
3
3
(Tz), 161.2 (3J ϭ J ϭ 8.9 Hz, Cp), 160.0 (3J ϭ J ϭ 8.8 Hz, Cp),
158.2 (2J ϭ 3J ϭ 3J ϭ 4.1 Hz, C3), 158.0 (CO), 149.2 (2J ϭ 6.5,
3
3
3J ϭ J ϭ 3.3 Hz, C5), 130.1 (1J ϭ 160.5, J ϭ 7.1 Hz, Co), 129.9
(1J ϭ 160.3, 3J ϭ 7.0 Hz, Co), 122.3 (3J ϭ 3J ϭ 7.8 Hz, Cipso), 119.7
(3J ϭ 3J ϭ 8.0 Hz, Cipso), 114.7 (1J ϭ 161.3, 3J ϭ 4.2 Hz, Cm),
114.2 (1J ϭ 160.8, 3J ϭ 4.6 Hz, Cm), 114.1 (1J ϭ 156.2 Hz, CH
The structure of 4 was solved by direct methods and conventional
Fourier techniques. The refinement was carried out by blocked full-
matrix, least-squares on F2.[29] The F atoms of the BF4 groups
Ϫ
and some carbon atoms (including the allyl group) were refined for
only two cycles anisotropically and in the last cycles the thermal
factors were fixed. These carbon atoms were refined with geometri-
cal restraints and a variable common carbon-carbon distance. The
rest of the non-hydrogen atoms were refined anisotropically. The
hydrogen atoms were calculated and refined as riding on the carbon
bonded atom with common isotropic displacement parameters.
allyl), 111.9 (1J ϭ 181.7 Hz, C4), 68.18 (1J ϭ 142.2, J ϭ 4.0 Hz,
2
OCH2), 67.74 (1J ϭ 142.9, 2J ϭ 3.7 Hz, OCH2), 63.8 (1J ϭ
162.8 Hz, CH2 allyl), 31.26 and 31.17 (1J ϭ 124.7 Hz, CH2), 19.17
and 19.15 (1J ϭ 125.4 Hz, CH2), 13.8 (1J ϭ 124.9 Hz, CH3).
Treatment of TPzbp2Tz with [Au(NO3)(PPh3)]. Formation of
[Au3(TPzbp2Tz)(PPh3)3](NO3)3 (9): This compound was prepared
by
a
procedure analogous to that described for 5, from
The molecular structure of 5 was solved by direct methods and
[AuCl(PPh3)] (74 mg, 0.15 mmol), AgNO3 (26 mg, 0.15 mmol), and conventional Fourier techniques and refined by full-matrix, least-
1 (TPzbp2Tz) (58 mg, 0.05 mmol). The obtained yellow solid was
squares on F2.[29] All non-hydrogen atoms were refined aniso-
purified by treatment with dichloromethane/hexane. Yield: 82 mg,
tropically except for the oxygen atoms in the nitrate group and the
60%. C126H126Au3N12O15P3 (2729.82): calcd. C 55.39, H 4.61, N last carbon atoms of the butoxy group, which were refined iso-
6.15; found C 55.00, H 4.39, N 6.01. IR (KBr): ν˜ ϭ 1611 cmϪ1 tropically. The hydrogen atoms were calculated and refined as rid-
ν(CϭN), 1384 νas(NO3). 1H NMR (400 MHz, CD2Cl2, 298 K): δ ϭ ing on the carbon-bonded atom with a common isotropic displace-
3
7.83 ppm (d, J ϭ 6.8 Hz, 6 H, Ho), 7.60Ϫ7.40 (m, 45 H, PPh3), ment parameter, except for the H2 bonded to N2, which was lo-
2702
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
Eur. J. Inorg. Chem. 2003, 2693Ϫ2704

New Tris(pyrazolyl)triazine and Pyrazolylpyridine Gold(I) and Palladium(II) Derivatives
FULL PAPER
Table 5. Crystal and refinement data for 4 and 5
4
5
Empirical formula
Formula mass
Temperature [K]
Crystal system
Space group
[C49H61N4O4Pd]3[BF4]3
2889.68
296(2)
Monoclinic
P21/n
21.811(1)
26.518(1)
25.889(2)
[C41H43N2O2PAu]NO3
885.72
296(2)
Triclinic
¯
P1
˚
a [A]
10.7447(9)
11.937(1)
15.560(1)
˚
b [A]
˚
C [A]
α [°]
β [°]
γ [°]
90
90.783(1)
90
14973(1)
102.475(1)
94.261(1)
102.699(2)
1890.5(3)
3
˚
V [A ]
Z
4
6024
2
888
F(000)
Crystal size [mm3]
0.22 ϫ 0.22 ϫ 0.14
1.284
0.431
0.30 ϫ 0.15 ϫ 0.07
1.556
3.981
dcalcd. [gcmϪ3
µ [mmϪ1
]
Scan technique
Data collected
θ [°]
Reflns. collected
Reflns. indep.
phi and omega
(Ϫ19, Ϫ31, Ϫ27) to (25, 31, 30)
3.82Ϫ25
58758
23261 (Rint ϭ 0.098)
23261/45/1174
10954
0.107
0.336
1.83
phi and omega
(Ϫ12, Ϫ14, Ϫ18) to (12, 11, 18)
1.35Ϫ25
9902
6578 (Rint ϭ 0.0451)
6578/0/421
4646
0.047
0.098
Data/restraints/parameters
Reflns.obsd. (I) Ͼ 2σ(I)
R1 (reflns. obsd.)[a]
[b]
RwF
Largest diff. peak [eAϪ3
]
1.30
[a]
[b]
2
2 2
R1 ϭ Σ(|Fo| Ϫ |Fc|)/Σ|Fo|. RwF ϭ {Σ[w(Fo Ϫ Fc ) ]/Σ[w(Fo2)2]}1/2
.
M. Munakata, L. P. Wu, M. Yamamoto, T. Kuroda-Sowa, M.
cated as one of the first peaks in a Fourier synthesis, included and
its positions refined.
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2704
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Eur. J. Inorg. Chem. 2003, 2693Ϫ2704