Exploring the reactivity towards acidic protic ligands of the Di-μ-hydroxo complex [NBu4]2[Pd2{C 4(COOMe)4}2(μ-OH)2]: A convenient precursor in the preparation of new palladacyclopentadiene complexes

Article abstract of DOI:10.1002/ejic.200401047

The dinuclear hydroxo complex [NBu₄]₂[Pd ₂{C₄(COOMe)₄}₂-(H-OH)₂] (I) reacts in a 1:2 molar ratio with a wide variety of protic electrophiles H(L) bearing different sets of donor atoms (L = O∧O, N∧S or O∧N) to give the mononuclear anionic palladium(n) derivatives with the general formula [Pd{C₄(COOMe)₄}(L)]- [O∧O = salycilaldehydate (sal) (1), acetohydroxamate (ahx) (2) and benzohydroxamate (bhx) (3); N∧S = 2-pyridinthiolate (spy) (4), 2-pyrimidinthiolate (spym) (5), 3-methyl-2-imidazolin-thiolate (meimt) (6) and 2-aminothiophenolate (2-atp) (7); O∧N = N-phenylsalycilaldiminate (N-phsal) (8), N-p- chlorophenylsalycilaldiminate (N-clsal) (9), N-p-tolylsalycilaldiminate (N-tolsal) (10), 2-aminophenolate (2-atp) (11), 2-pyrrole-carboxaldeydate (2-pcal) (12), 8-hydroxiquinolinate (oxin) (13), picolinate (2-pic) (14)]. Structural characterisation by X-ray diffraction of complexes 5, 8 and 13 confirmed the proposed formula. Dinuclear complexes [NBu₄] ₂ [Pd{C₄(COOMe)₄}(μ-az)]₂ (az = pyrazolate (pz) (15), triazolate (tz) (16) and 3,5-dimethylpyrazolate (3,5-Me₂pz) (17) were obtained when treating I with azoles in the same molar ratio, and also treating the hydroxo complex with chloranilic acid (chl) (18) and squarate (sq) (19) in 1:1 proportion to yield compounds [NBu ₄]₂[Pd{C₄(COOMe)₄} ₂{(μ-O-O)}] with the ligands acting as bis-bidentate ones. A related process takes place when (I) reacts with ammonium O,Oprime;- dialkyldithiophosphates in acetone under mild conditions and complexes [NBu ₄][Pd{C₄(COOMe)₄}{S(S)P(OR)₂}] (R = Me (20), Et (21), iPr (22)) are obtained. Deprotonation of secondary amines Et₂NH, Pr₂NH, piperidine or morpholine by (I) in the presence of carbon disulfide leads to the corresponding dithiocarbamate complexes [Pd{C₄(COOMe)₄}-(S₂CNR₂)] 23-26. (I) also promotes the nucleophilic addition of water to pyridine-2-carbonitrile and a mononuclear complex 27 containing the pyridine-2-carboxamidate ligand is formed. Its structure has been determined by a single-crystal diffraction study. The new complexes were fully characterised by analytical and spectroscopic techniques (FAB-MS, IR; 1H, ¹³C and ³¹P-NMR). Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.

Full text of DOI:10.1002/ejic.200401047

FULL PAPER
Exploring the Reactivity towards Acidic Protic Ligands of the Di-μ-hydroxo
Complex [NBu4]2[Pd2{C4(COOMe)4}2(μ-OH)2]: A Convenient Precursor in the
Preparation of New Palladacyclopentadiene Complexes
Gregorio Sánchez,*[a] Jorge Vives,[a] Gregorio López,[a] José Luis Serrano,[b] Luis García,[b]
and José Pérez[b]
Keywords: Palladacyclopentadiene complexes / Hydroxo complexes / Metallacycles / Cycloaddition
The dinuclear hydroxo complex [NBu4]2[Pd2{C4(COOMe)4}2-
(μ-OH)2] (I) reacts in a 1:2 molar ratio with a wide variety of
protic electrophiles H(L) bearing different sets of donor
chloranilic acid (chl) (18) and squarate (sq) (19) in 1:1 pro-
portion to yield compounds [NBu4]2[Pd{C4(COOMe)4}2{(μ-O–
O)}] with the ligands acting as bis-bidentate ones. A related
∧
∧
∧
atoms (L = O O, N S or O N) to give the mononuclear an- process takes place when (I) reacts with ammonium O,OЈ-
ionic palladium(II) derivatives with the general formula
dialkyldithiophosphates in acetone under mild conditions
and complexes [NBu4][Pd{C4(COOMe)4}{S(S)P(OR)2}] (R =
Me (20), Et (21), iPr (22)) are obtained. Deprotonation of sec-
ondary amines Et2NH, Pr2NH, piperidine or morpholine by
∧
[Pd{C4(COOMe)4}(L)]– [O O = salycilaldehydate (sal) (1),
acetohydroxamate (ahx) (2) and benzohydroxamate (bhx) (3);
∧
N S = 2-pyridinthiolate (spy) (4), 2-pyrimidinthiolate (spym)
(5), 3-methyl-2-imidazolin-thiolate (meimt) (6) and 2-amino- (I) in the presence of carbon disulfide leads to the corre-
∧
thiophenolate (2-atp) (7); O N = N-phenylsalycilaldiminate
(N-phsal) (8), N-p-chlorophenylsalycilaldiminate (N-clsal)
sponding dithiocarbamate complexes [Pd{C4(COOMe)4}-
(S2CNR2)] 23–26. (I) also promotes the nucleophilic addition
(9), N-p-tolylsalycilaldiminate (N-tolsal) (10), 2-aminophe- of water to pyridine-2-carbonitrile and a mononuclear com-
nolate (2-atp) (11), 2-pyrrole-carboxaldeydate (2-pcal) (12),
8-hydroxiquinolinate (oxin) (13), picolinate (2-pic) (14)].
Structural characterisation by X-ray diffraction of complexes
5, 8 and 13 confirmed the proposed formula. Dinuclear com-
plexes [NBu4]2 [Pd{C4(COOMe)4}(μ-az)]2 (az = pyrazolate
(pz) (15), triazolate (tz) (16) and 3,5-dimethylpyrazolate (3,5-
Me2pz) (17) were obtained when treating I with azoles in the
same molar ratio, and also treating the hydroxo complex with
plex 27 containing the pyridine-2-carboxamidate ligand is
formed. Its structure has been determined by a single-crystal
diffraction study. The new complexes were fully character-
ised by analytical and spectroscopic techniques (FAB-MS, IR;
1H, 13C and 31P-NMR).
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2005)
and co-oligomerization catalytic reactions,[4] and also be-
cause of the interesting behaviour as precursors in organo-
metallic chemistry of the compounds formed. Specifically,
the polymeric palladacyclopentadiene complex [1,2,3,4-
tetrakis(methoxycarbonyl)-1,3-butadiene-1,4-diyl]palla-
dium(ii) (TCPC) [Pd(C4(COOMe)4)]n, obtained in the reac-
tion of dmad with Pd(dba)2 (dba = dibenzylidenacetone)
reacts with a wide range of donor ligands to give soluble
discrete molecules,[2,3,5,6] although to date, just a few crystal
structures of such palladacyclopentadiene compounds are
known.[7,8] Other interesting features recently studied are
their use as catalysts in several types of reactions. Thus,
intramolecular carbametalation and [2 + 2 + 2] cycload-
dition,[9] enyne metathesis accompanied by skeletal re-
arrangement,[10,11] co-cyclotrimerization of various al-
kynes[5], and hydrostannation of cyclopropenes,[12] have em-
ployed TCPC amongst other derivatives as the catalyst. In
this sense, in the frame of our collaboration with Fairlamb
and co-workers, we have reported the first application of
mononuclear palladacyclopentadiene complexes containing
Introduction
The chemistry of metallacycles has received growing
interest during the last few years, as a result of their involve-
ment in catalytic processes and their applications in organic
synthesis.[1] The cycloaddition of two unsaturated frag-
ments to a metal unit is one of the most useful methods
of metallacycle synthesis, since it gives access to relatively
complex structures starting from small unsaturated mole-
cules.[1a] In particular, the oxidative cycloaddition of acety-
lenic esters such as dimethylacetylenedicarboxylate (dmad)
to Ni, Pd and Pt has received attention in the past,[2,3] in
part because of its involvement in different oligomerization
[a] Departamento de Química Inorgánica, Universidad de Murcia,
30071 Murcia, Spain
E-mail: gsg@um.es
[b] Departamento de Ingeniería Minera, Geológica y Cartográfica,
Área de Química Inorgánica, Universidad Politécnica de Cart-
agena,
30203 Cartagena, Spain
E-mail: jose.serrano@upct.es
2360
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
DOI: 10.1002/ejic.200401047
Eur. J. Inorg. Chem. 2005, 2360–2367

Reactivity of a Di-μ-hydroxo Complex with Protic Ligands
FULL PAPER
imidato ligands as catalysts in standard Stille cross-coupling the addition of water experienced by pyridine-2-carbonitrile
reactions,[13]stating that yields and reaction times are de- when [Pd2{C4(COOMe)4}2(μ-OH)2][NBu4]2 is present in
pendent on the presence and type of these ligands. The ex- the reaction.
ceptional catalytic properties of related dinuclear derivatives
are currently under investigation, and suggest potential ap-
plications of compounds presented here.
Results and Discussion
On the other hand, in addition to their interest related
to applied fields such antitumour activity of PtII complexes
The
palladacyclopentadiene
complex
[Pd2{C4-
or catalytic processes,[14] the synthetic value of palladium(ii) (COOMe)4}2(μ-OH)2]2– (I) was conveniently prepared by
and platinum(ii) di-μ-hydroxo complexes is a subject of reaction of the polymeric complex [Pd{C4(COOMe)4}]n
growing study. For example, Sharp[15,16] and later others[17] with NBu4OH in water.[13] Its reactivity was easily followed
have employed several such complexes as precursors in the by the disappearance of both an IR stretching vibration at
1
preparation of scarce oxo and imido derivatives that are 3600 cm–1 and a high-field shielded H NMR resonance at
also relevant to C–O and C–N bond forming reactions in δ = –0.85 ppm. The reactions explored in this paper are
catalytic processes.[14] The reactivity towards protic sub- displayed in Scheme 1 and specific conditions followed for
strates of dinuclear compounds [Pd(μ-OH)Ln]2 (Ln = ortho- each of them are collected in the experimental section.
metallated imine-based ligands) provides a general route to
The hydroxo complex reacts with weak protic acids H(L)
obtain dinuclear complexes with double and mixed bridges to give mono- or binuclear species depending on whether
that have shown liquid crystal behaviour.[18] In this sense, the deprotonated acid (L)– is exo- or endo-bidentate. These
during the last few years we have also been developing the reactions can be viewed as an initial proton abstraction by
usefulness of binuclear hydroxo complexes of palladium in (I) that provides (L)– and the metal substrate, subsequently
the preparation of an extensive selection of new com- trapped by the anion to form the new complexes. The pro-
pounds, by means of a simple acid-base reaction.[19] Our tonation at the nucleophilic oxygen atom of the bridging
more recent contribution to the area has been the synthesis OH should give an initial aqua complex that experiences
of the dinuclear complex [Pd2{C4(COOMe)4}2(μ-OH)2]- H2O replacement by the endo- or exo-bidentated (L)– lead-
[NBu4]2 and its use in the preparation of new palladacyclo- ing to the formation of [Pd{C4(COOMe)4}(L)]– (1–14) or
2–
pentadiene derivatives that, as mentioned above, have [Pd{C4(COOMe)4}(μ- L)]2 (15–17) respectively. Similarly,
shown interesting catalytic properties.[13] We expand in this the use of ligands able to coordinate in a bis-bidentate mode
paper on the reactivity of this complex towards several pro- reacting with the precursor (I) in a 1:1 molar ratio allows
tic electrophiles and describe other related reactions, like the obtention of complexes 18 and 19. The considerable
that against amines in the presence of carbon disulfide or nucleophilicity of the bridging OH groups of I makes it also
Scheme 1. Reactivity of the hydroxo complex [NBu4]2[Pd2{C4(COOMe)4}2(μ-OH)2] (I).
Eur. J. Inorg. Chem. 2005, 2360–2367
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G. Sánchez, J. Vives, G. López, José L. Serrano, L. García, J. Pérez
FULL PAPER
reactive towards ammonium O,OЈ-dialkyldithiophosphates, gands 4–7, as NMR spectroscopic data would be compati-
yielding complexes 20–22 with the concomitant release of ble with either mononuclear complexes with the ligands act-
NH3 and H2O. The preparation of the dithiocarbamate ing in a chelating mode or dinuclear complexes with bridg-
complexes 23–26 should involve a first step of amine depro- ing ligands. This extent has been further proved by X-ray
tonation, followed by nucleophilic attack of R2N– to carbon diffraction analysis of compound 5 whose structure and se-
disulfide to form the dithiocarbamate anion. On the other lected bond lengths and angles are shown in Figure 1 and
hand, the activation of nitriles with respect to attack by Table 1. The Pd–N and Pd–S distances are slightly longer
nucleophiles in the coordination sphere of metal ions has than the ones found for related PdII complexes with this
attracted considerable interest.[20] We have described the at- ligand[23] and the N(1)–Pd–S(1) angle is considerably
tack of OH– and MeO– on benzonitrile coordinated to smaller than 90°, in agreement with previously reported
PtII[21] and the use of the hydroxo complex [{Ni(C6F5)2(μ- data for four-membered N,S-chelate rings.[24,25]
OH)}2]2– in the formation of complexes containing amidate
ligands,[22] and now we employ a similar reaction between
I and pyridine-2-carbonitrile in acetone/water to prepare
complex 27.
The new palladium complexes are air-stable and their IR
spectra show two very strong bands [ν(CO)] around
1700 cm–1 characteristic of the carboxylate groups,[2] in
some cases partly overlapped by those absorptions attrib-
uted to the incoming deprotonated ligands (see Exp. Sec-
tion). The 1H-NMR spectra show the corresponding signals
of these ligands, and as a common feature the characteristic
chemical shifts of the methoxycarbonyl groups, which act
as a preliminary probe for the compounds geometry, i.e.,
symmetric complexes show two signals and asymmetric
show four resonances, in accordance with previous re-
sults.[7,8]
Figure 1. ORTEP diagram of anion complex 5 with the atom num-
bering Scheme; thermal spheres are drawn at the 50% probability
level.
The proposed nuclearity of the new complexes is also
confirmed by FAB mass spectrometry and the negative
FAB-MS data of the complexes with the m/z values for the
observed fragments are collected in the experimental sec-
The mononuclear nature of complexes 8 and 13 that con-
tion. The abundance of the signals around the parent ion tain chelating ON donor ligands has also been confirmed
are consistent in all cases with the natural isotopic abun- by single-crystal X-ray analysis. The ORTEP diagrams of
dances. This technique has special relevance conferring the the two anions are shown in Figure 2 and Figure 3, while
mononuclearity of complexes with heterocyclic-2 thiolate li- the relevant bond lengths and angles are reported in
Table 1. Selected bond lengths [Å] and angles [°] for complexes 5, 8, 13, 20 and 27.
5
8
13
20
27
Pd(1)–C(1)
Pd(1)–C(4)
Pd(1)–N(1)
Pd(1)–N(2)
2.023(3)
1.986(3)
2.114(3)
2.007(3)
2.002(3)
2.111(2)
2.019(2)
1.981(2)
2.122(2)
2.05(3)
2.00(2)
2.036(7)
1.741(6)
1.882(5)
2.040(5)
Pd(1)–S(1)
Pd(1)–S(2)
2.3734(8)
2.406(8)
2.396(7)
Pd(1)–O(9)
2.0636(19)
79.46(11)
178.80(10)
2.0689(17)
79.30(9)
171.32(9)
C(4)–Pd(1)–C(1)
C(4)–Pd(1)–N(1)
C(4)–Pd(1)–N(2)
C(1)–Pd(1)–N(1)
C(1)–Pd(1)–N(2)
C(4)–Pd(1)–O(9)
C(1)–Pd(1)–O(9)
C(4)–Pd(1)–S(1)
C(1)–Pd(1)–S(1)
C(4)–Pd(1)–S(2)
C(1)–Pd(1)–S(2)
N(1)–Pd(1)–N(2)
N(1)–Pd(1)–S(1)
O(9)–Pd(1)–N(1)
S(1)–Pd(1)–S(2)
79.29(12)
172.48(11)
79.9(4)
79.6(3)
172.4(3)
96.9(3)
107.1(2)
176.4(2)
107.37(11)
101.51(10)
106.33(9)
90.83(10)
167.91(9)
94.00(8)
172.73(8)
103.85(8)
176.77(9)
177.8(7)
99.6(8)
97.0(7)
176.5(7)
76.5(2)
69.45(7)
88.12(8)
80.66(7)
83.53(10)
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Reactivity of a Di-μ-hydroxo Complex with Protic Ligands
FULL PAPER
Table 1. The torsion angles of the six-membered ring che- all similar with values of ca. 2 Å, with independence of the
late in (8) suggest for it a distorted sofa conformation.[26]
donor atom placed in trans- to the metallacyclic carbon.
However, the distance Pd(1)–C(4) in complex 27 trans- to
the pyridinic nitrogen is comparatively shorter. In this
structure (Figure 5) is also found a short Pd(1)–N(1) dis-
tance if compared with the analogous one in complex 5
with the 2-pyrimidinthiolate ligand described above.
Figure 2. X-ray crystal structure of 8. Thermal ellipsoids are drawn
at 50% probability. Hydrogens omitted for clarity.
Figure 5. Structure of the [Pd{C4(COOMe)4}(2-HNCOpy)]– anion
in the single crystal structure of 27. All hydrogen atoms have been
omitted for clarity.
The five new structures may be described as nearly
planar, and their deviation from the planar coordination
has been quantified by the N1*C1C4Pd1 and E**C4C1Pd1
improper torsion angles (see Table 2).[28]
Table 2. Distortion parameters from square-planar coordination.
Improper torsion
angles [°]
5
8
13
20
27
N(1)[a] C(1)–C(4)–Pd(1) 2.19
–0.47
5.19
4.17
1.98
–1.55 –2.14
–1.19 –0.60
E[b] C(4)–C(1)–Pd(1)
–0.53
Figure 3. An ORTEP representation of 13.
[a] Except 20 (S1). [b] E = S(1) 5; O(9) 8, 13; S(2) 20 and N(2) 27.
The structure of the dimethyldithiophosphate complex
20 has been established and is shown in Figure 4. The Pd–
S distances are slightly longer than those found in related
complexes (Table 1).[27] It can be inferred from this Table
that the Pd–C bond lengths in complexes 5, 8, 13, 21 are
Experimental Section
General Remarks for Synthesis: C,H,N,S analyses were carried out
with a Carlo–Erba model 1108 microanalyser. IR spectra were re-
corded with a Perkin–Elmer spectrophotometer 16F PC FT-IR,
using Nujol mulls between polyethylene sheets. NMR spectroscopic
data were recorded on Bruker Avance 200, 300 and 400 spectrome-
ters. Mass spectrometric analyses were performed with a Fisons
VG Autospec double-focusing spectrometer, operated in the nega-
tive mode. Ions were produced by fast atom bombardment (FAB)
with a beam of 25-keV Cs atoms. The mass spectrometer was oper-
ated with an accelerating voltage of 8 kV and a resolution of at
least 1000. The hydroxo complex precursor [NBu4]2[Pd2-
{C4(COOMe)4}2(μ-OH)2] was prepared by a published method.[13]
Reagents were purchased from commercial sources and used di-
rectly unless otherwise stated in the text.
Preparations
Complexes [NBu4][Pd[C4(COOMe)4}(O–O)] [O–O: Salycilaldehyd-
ate (sal) (1), Acetohydroxamate (ahx) (2) and Benzohydroxamate
(bhx) (3)]: These mononuclear complexes were obtained according
Figure 4. ORTEP diagram of 20; thermal ellipsoids are drawn at
the 50% probability level.
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G. Sánchez, J. Vives, G. López, José L. Serrano, L. García, J. Pérez
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to the following general method. To an acetone solution (10 mL)
of hydroxo complex (0.07 g, 0.054 mmol) the stoichiometric
amount of H(O–O) (molar ratio 1:2) was added. The solution was
stirred at room temperature for 30 min and the solvent was partly
evaporated under reduced pressure. The addition of diethyl ether
caused the formation of yellow-orange solids, which were filtered
off, washed with diethyl ether and air-dried. The compounds were
recrystallised from dichloromethane/diethyl ether.
(vs), 1698 (vs), 1570 (s), 1554 (s) cm–1. 1H NMR (200 MHz,
CDCl3): δ = 3.61 (s, 3 H, COOMe), 3.63 (s, 3 H, COOMe), 3.67
(s, 3 H, COOMe), 3.72 (s, 3 H, COOMe), 6.61 (m, 1 H, spym),
8.01 (dd, 1 H, spym, J3 = 5.0, J4 = 2.5 Hz), 8.24 (dd, 1 H, spym,
J3 = 5.0, J4 = 2.5 Hz) ppm. 13C NMR (200 MHz, CDCl3): δ = 51.0
(COOMe), 51.2 (COOMe) ppm. FAB-MS (negative mode): m/z (%)
= 501 [Pd{C4(COOMe)4}(spym)]–.
[NBu4][Pd{C4(COOMe)4}(meimt)] (6): Yield 0.087 g (76%), m.p.
135 °C. C32H53N3O8PdS (746.26): calcd. C 51.5, H 7.2, N 5.6, S
[NBu4][Pd(C4{COOMe}4)(sal)] (1): Yield 0.072 g (88%), m.p.
153 °C (dec.). C35H53NO10Pd (754.2): calcd. C 55.7, H 7.1, N 1.9;
4.3; found C 51.2, H 7.3, N 5.9, S 4.2. IR (Nujol) ν = 1694 (vs),
˜
1532 (s) cm–1. 1H NMR (300 MHz, CDCl3): δ = 3.09 (s, 3 H, Me),
3.41 (s, 3 H, COOMe), 3.42 (s, 3 H, COOMe), 3.47 (s, 3 H, CO-
OMe), 3.63 (s, 3 H, COOMe), 6.21 (d, 1 H, meimt, J = 1.4 Hz),
6.36 (d, 1 H, meimt, J = 1.4 Hz) ppm. 13C NMR (300 MHz,
CDCl3): δ = 34.3 (meimt), 48.0 (COOMe), 49.1 (COOMe), 49.2
(COOMe), 49.3 (COOMe) ppm. FAB-MS (negative mode): m/z (%)
= 501 [Pd{C4(COOMe)4}(meimt)]–.
found C 55.5, H 7.0, N 2.0. IR (Nujol) ν = 1692 (vs), 1612 (vs),
˜
1596 (vs), 1556 (vs) cm–1. 1H NMR (300 MHz, CDCl3): δ = 3.60
(s, 6 H, COOMe), 3.75 (s, 3 H, COOMe), 3.80 (s, 3 H, COOMe),
6.39 (m, 1 H, aromatic), 6.64 (d, 1 H, aromatic, J = 8.8 Hz), 7.17–
7.27 (m, 2 H, aromatics), 9.06 (s, 1 H, CH=O) ppm. 13C NMR
(300 MHz, CDCl3): δ = 50.9 (COOMe), 51.0 (COOMe), 51.2 (CO-
OMe) ppm. FAB-MS (negative mode): m/z (%)
=
512
[Pd{C4(COOMe)4}(sal)]– + 1.
[NBu4][Pd{C4(COOMe)4}(2-atp)] (7): Yield 0.087 g (75%), m.p.
145 °C (dec.). C34H54N2O8PdS (757.29): calcd. C 53.9, H 7.2, N
[NBu4][Pd(C4{COOMe}4)(ahx)] (2): Yield 0.068 g (89%), m.p.
180 °C (dec.). C30H52N2O10Pd (707.2): calcd. C 50.9, H 7.4, N 4.0;
3.7, S 4.2; found C 54.1, H 7.5, N 3.8, S 4.4. IR (Nujol) ν =
˜
3292 (m), 3252 (m), 1674 (s), 1592 (s) cm–1. 1H NMR (300 MHz,
CDCl3): δ = 3.60 (s, 3 H, COOMe), 3.69 (s, 3 H, COOMe), 3.72
(s, 3 H, COOMe), 3.77 (s, 3 H, COOMe), 4.64 (s, 2 H, NH2), 6.70
(m, 1 H, 2-atp), 6.89 (m, 1 H, 2-atp), 6.97 (m, 1 H, 2-atp), 7.42 (m,
1 H, 2-atp) ppm. 13C NMR (300 MHz, CDCl3): δ = 50.8 (CO-
OMe), 50.9 (COOMe), 51.0 (COOMe), 51.1 (COOMe) ppm. FAB-
MS (negative mode): m/z (%) = 514 [Pd{C4(COOMe)4}(2-atp)]–.
found C 50.6, H 7.3, N 4.0. IR (Nujol) ν = 3155 (m) (ν NH),
˜
1726 (vs), 1709 (vs), 1688 (vs), 1592 (vs) cm–1. 1H NMR (400 MHz,
CDCl3): δ = 1.92 (s, 3 H, Me), 3.58 (s, 6 H, COOMe), 3.65 (s, 3
H, COOMe), 3.74 (s, 3 H, COOMe), 10.42 (br., 1 H, NH) ppm.
13C NMR (400 MHz, CDCl3): δ = 16.7 (Me), 50.7 (COOMe), 50.8
(COOMe), 51.0 (COOMe), 51.1 (COOMe) ppm. FAB-MS (nega-
tive mode): m/z (%) = 463 [Pd{C4(COOMe)4}(ahx)]– – 1; 448
[Pd{C4(COOMe)4}(O–NH–CO)]– – 1.
Complexes [NBu4][Pd{C4(COOMe)4}(N–O)] [H(N–O): N-Phenyl-
salycilaldimine (N-phsal) (8), N-p-Chlorophenylsalycilaldimine (N-
clsal) (9), N-p-Tolylsalycilaldimine (N-tolsal) (10), 2-Aminophenol
(2-ap) (11), 2-Pyrrolecarboxaldeyde (2-pcal) (12), 8-Hydroxiquino-
line (oxin) (13), Picolinic Acid (2-pic) (14): The complexes were ob-
tained by treating [NBu4]2[Pd2{C4(COOMe)4}2(μ-OH)2] (0.100 g,
0.077 mmol) with the corresponding protic ligand (HO–N) (molar
ratio 1:2) in acetone (10 mL). The solution was stirred at room
temperature for 30 min and then concentrated under reduced pres-
sure until ca. one fifth of the initial volume. Slow addition of di-
ethyl ether caused the formation of yellow complexes, which were
filtered off, washed with diethyl ether and air-dried. The com-
pounds were recrystallised from dichloromethane/diethyl ether.
[NBu4][Pd(C4{COOMe}4)(bhx)] (3): Yield 0.063 g (76%), m.p.
203 °C (dec.). C35H54N2O10Pd (769.2): calcd. C 54.6, H 7.1, N 3.6;
found C 54.8, H 7.3, N 3.8. IR (Nujol) ν = 3268 (s) cm–1 (ν NH),
˜
1698 (vs), 1682 (vs), 1596 (vs), 1572 (vs) cm–1. 1H NMR (200 MHz,
CD3CN): δ = 3.55 (s, 6 H, COOMe), 3.61 (s, 3 H, COOMe), 3.71
(s, 3 H, COOMe), 7.38–7.49 (m, 3 H, aromatics), 7.66–7.69 (m, 2
H, aromatics), 10.38 (br., 1 H, NH) ppm. 13C NMR (200 MHz,
CDCl3): δ = 50.1 (COOMe), 50.2 (COOMe) ppm. FAB-MS (nega-
tive mode): m/z (%) = 526 [Pd{C4(COOMe)4}(bhx)]–.
Complexes [NBu4][Pd{C4(COOMe)4}(N–S)] [N–S: 2-Pyridinthiol-
ate (spy) (4), 2-Pyrimidinthiolate (spym) (5) 3-Methyl-2-imidazolin-
thiolate (meimt) (6) and 2-Aminothiophenolate (2-atp) (7)]: The com-
plexes were obtained by treating [NBu4]2[Pd2{C4(COOMe)4}2(μ-
OH)2] (0.100 g, 0.077 mmol) with the corresponding heterocyclic-
2-thione or 2-aminothiophenol (molar ratio 1:2) in acetone
(10 mL). The solution was stirred at room temperature for 30 min
and then concentrated under reduced pressure until half volume.
Slow addition of diethyl ether caused the formation of yellow com-
plexes, which were filtered off, washed with diethyl ether and air-
dried. The compounds were recrystallised from dichloromethane/
diethyl ether.
[NBu4][Pd{C4(COOMe)4}(N-phsal)] (8): Yield 0.106 g (83%), m.p.
175 °C (dec.). C41H58N2O9Pd (829.33): calcd. C 59.4, H 7.0, N 3.4;
found C 59.2, H 7.2, N 3.7. IR (Nujol) ν = 1700 (vs), 1686 (vs),
˜
1
1606 (s), 1586 (s), 1530 (s) cm–1. H NMR (200 MHz, CDCl3): δ =
2.84 (s, 3 H, COOMe), 3.56 (s, 3 H, COOMe), 3.59 (s, 3 H, CO-
OMe), 3.90 (s, 3 H, COOMe), 6.40 (m, 1 H, N-phsal), 6.77 (d, 1
H, N-phsal, J = 8.4 Hz), 7.08 (m, 1 H, N-phsal), 7.15 (m, 2 H, N-
phsal), 7.32 (m, 4 H, N-phsal), 7.94 (s, 1 H, CH=N) ppm. 13C
NMR (200 MHz, CDCl3):
δ = 50.7 (COOMe), 50.9 (CO-
OMe) ppm. FAB-MS (negative mode): m/z (%)
=
586
[NBu4][Pd{C4(COOMe)4}(spy)] (4): Yield 0.086 g (75%), m.p.
131 °C (dec.). C33H52N2O8PdS (743.26): calcd. C 53.3, H 7.0, N
[Pd{C4(COOMe)4}(N-phsal)]–.
3.8, S 4.3; found C 53.2, H 7.0, N 3.7, S 4.4. IR (Nujol) ν =
˜
[NBu4][Pd{C4(COOMe)4}(N-clsal)] (9): Yield 0.105 g (80%), m.p.
160 °C (dec.). C41H57ClN2O9Pd (863.77): calcd. C 57.0, H 6.6, N
1716 (vs), 1694 (vs), 1594 (s), 1578 (s) cm–1. 1H NMR (200 MHz,
CDCl3): δ = 3.62 (s, 3 H, COOMe), 3.64 (s, 3 H, COOMe), 3.68
(s, 3 H, COOMe), 3.77 (s, 3 H, COOMe), 6.61 (m, 1 H, spy), 6.79
(m, 1 H, spy), 7.23 (m, 1 H, spy), 7.79 (m, 1 H, spy) ppm. 13C NMR
(200 MHz, CDCl3): δ = 51.0 (COOMe), 51.3 (COOMe) ppm. FAB-
MS (negative mode): m/z (%) = 500 [Pd{C4(COOMe)4}(spy)]–.
3.2; found C 57.3, H 6.9, N 3.0. IR (Nujol) ν = 1688 (vs), 1606 (s),
˜
1572 (s), 1526 (s) cm–1. 1H NMR (300 MHz, CDCl3): δ = 3.00 (s,
3 H, COOMe), 3.63 (s, 3 H, COOMe), 3.64 (s, 3 H, COOMe), 3.95
(s, 3 H, COOMe), 6.46 (m, 1 H, N-clsal), 6.82 (d, 1 H, N-clsal, J
= 8.5 Hz), 7.25 (m, 6 H, N-clsal), 7.95 (s, 1 H, CH=N) ppm. 13C
NMR (300 MHz, CDCl3): δ = 50.5 (COOMe), 50.8 (COOMe), 50.9
(COOMe), 51.0 (COOMe) ppm. FAB-MS (negative mode): m/z (%)
= 622 [Pd{C4(COOMe)4}(N-clsal)]–.
[NBu4][Pd{C4(COOMe)4}(spym)] (5): Yield 0.082 g (72%), m.p.
130 °C (dec.). C32H51N3O8PdS (744.25): calcd. C 51.6, H 6.9, N
5.6, S 4.3; found C 51.4, H 6.8, N 5.6, S 4.2. IR (Nujol) ν = 1712
˜
2364
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
Eur. J. Inorg. Chem. 2005, 2360–2367

Reactivity of a Di-μ-hydroxo Complex with Protic Ligands
FULL PAPER
[NBu4][Pd{C4(COOMe)4}(N-tolsal)] (10): Yield 0.097 g (75%), m.p.
[NBu4]2[Pd(C4{COOMe}4)(μ-pz)]2 (15): Yield 0.051 g (68%), m.p.
136 °C (dec.). C42H60N2O9Pd (843.35): calcd. C 59.8, H 7.2, N 3.3;
160 °C (dec.). C62H102N6O16Pd2 (1400.34): calcd. C 53.2, H 7.3, N
found C 59.9, H 7.4, N 3.4. IR (Nujol) ν = 1702 (vs), 1686 (s),
6.0; found C 53.4, H 7.5, N 6.3. IR (Nujol) ν = 1688 (vs),
˜
˜
1
1600 (s), 1586 (s), 1530 (s) cm–1. H NMR (300 MHz, CDCl3): δ = 1616 (s) cm–1. 1H NMR (200 MHz, CDCl3): δ = 3.37 (s, 12 H, CO-
2.33 (s, 3 H, Me), 2.86 (s, 3 H, COOMe), 3.57 (s, 3 H, COOMe), OMe), 3.58 (s, 12 H, COOMe), 5.89 (m, 2 H, pz), 7.26 (m, 4 H,
3.59 (s, 3 H, COOMe), 3.90 (s, 3 H, COOMe), 6.40 (m, 1 H, N- pz) ppm. 13C NMR (200 MHz, CDCl3): δ = 50.6 (COOMe), 50.7
tolsal), 6.76 (d, 1 H, N-tolsal, J = 8.4 Hz), 7.16 (m, 6 H, N-tolsal),
(COOMe), 101.3 (pz), 137.3 (pz) ppm. FAB-MS (negative mode):
7.93 (s, 1 H, CH=N) ppm. 13C NMR (300 MHz, CDCl3): δ = 20.8 m/z (%) = 1158 [(NBu4)Pd2{C4(COOMe)4}2(μ-pz)2]–, 917 [Pd2{C4-
(Me), 50.5 (COOMe), 50.9 (COOMe), 51.0 (COOMe) ppm.
FAB-MS (negative mode): m/z (%) = 600 [Pd{C4(COOMe)4}(N-
tolsal)]–.
(COOMe)4}2(μ-pz)2]– + 1, 849 [Pd2{C4(COOMe)4}2(μ-pz)]–.
[NBu4]2[Pd(C4{COOMe}4)(μ-tz)]2 (16): Yield 0.055 g (72%), m.p.
167 °C (dec.). C60H100N8O16Pd2 (1402.3): calcd. C 51.4, H 7.2, N
[NBu4][Pd{C4(COOMe)4}(2-ap)] (11): Yield 0.102 g (90%), m.p.
165 °C (dec.). C34H54N2O9Pd (741.22): calcd. C 55.1, H 7.3, N 3.8;
8.0; found C 51.6, H 7.2, N 8.3. IR (Nujol) ν = 1692 (vs),
˜
1552 (s) cm–1. 1H NMR (200 MHz, CDCl3): δ = 3.40 (s, 12 H, CO-
OMe), 3.59 (s, 12 H, COOMe), 7.73 (m, 4 H, tz) ppm. 13C NMR
(200 MHz, CDCl3): δ = 50.5 (COOMe), 50.7 (COOMe), 150.0
(tz) ppm. FAB-MS (negative mode): m/z (%) = 1160 [(NBu4)-
Pd2{C4(COOMe)4}2(μ-tz)2]–, 919 [Pd2{C4(COOMe)4}2(μ-tz)2]– + 1,
851 [Pd2{C4(COOMe)4}2(μ-tz)]–.
found C 55.3, H 7.5, N 3.6. IR (Nujol) ν = 3310 (m), 3260 (m),
˜
1
1688 (s), 1598 (s), 1538 (s) cm–1. H NMR (200 MHz, CDCl3): δ =
3.61 (s, 3 H, COOMe), 3.67 (s, 3 H, COOMe), 3.68 (s, 3 H, CO-
OMe), 3.82 (s, 3 H, COOMe), 4.18 (s, 2 H, NH2), 6.25 (m, 1 H, 2-
ap), 6.60 (d, 1 H, 2-ap, J = 7.8 Hz), 6.87 (m, 2 H, 2-ap) ppm. 13C
NMR (200 MHz, CDCl3): δ = 51.1 (COOMe), 51.2 (COOMe), 51.3
[NBu4]2[Pd(C4{COOMe}4)(μ-3,5-Me2pz)]2 (17): Yield 0.053 g
(67%), m.p. 167 °C (dec.). C66H110N6O16Pd2 (1456.45): calcd. C
(COOMe) ppm. FAB-MS (negative mode): m/z (%)
= 499
[Pd{C4(COOMe)4}(2-ap)]–.
54.4, H 7.6, N 5.8; found C 54.5, H 7.7, N 6.0. IR (Nujol) ν =
˜
1698 (vs), 1642 (s), 1546 (s) cm–1. 1H NMR (200 MHz, CDCl3): δ
= 2.18 (s, 12 H, 3,5-Me2pz) 3.37 (s, 12 H, COOMe), 3.57 (s, 12
H, COOMe), 5.34 (s, 2 H, 3,5-Me2pz) ppm. 13C NMR (200 MHz,
CDCl3): δ = 14.1 (3,5-Me2pz), 50.4 (COOMe), 50.5 (COOMe),
100.4 (3,5-Me2pz), 146.6 (3,5-Me2pz) ppm. FAB-MS (negative
[NBu4][Pd{C4(COOMe)4}(2-pcal)] (12): Yield 0.075 g (67%), m.p.
155 °C (dec.). C33H52N2O9Pd (727.19): calcd. C 54.5, H 7.2, N 3.8;
found C 54.7, H 7.3, N 4.0. IR (Nujol) ν = 1694 (vs), 1564 (s) cm–1.
˜
1H NMR (200 MHz, CDCl3): δ = 3.63 (s, 3 H, COOMe), 3.64 (s,
3 H, COOMe), 3.78 (s, 3 H, COOMe), 3.80 (s, 3 H, COOMe), 6.24
(d, 1 H, 2-pcal, J = 4.0 Hz), 6.96 (d, 1 H, 2-pcal, J = 4.0 Hz), 7.05
(m, 1 H, 2-pcal), 8.53 (s, 1 H, CHO) ppm. 13C NMR (200 MHz,
CDCl3): δ = 50.9 (COOMe), 51.0 (COOMe), 51.2 (COOMe), 51.3
mode): m/z (%)
=
1214 [(NBu4)Pd2{C4(COOMe)4}2(μ-3,5-
Me2pz)2]–, 973 [Pd2{C4(COOMe)4}2(μ-3,5-Me2pz)2]– + 1, 877 [Pd2-
{C4(COOMe)4}2(μ-3,5-Me2pz)]–.
(COOMe) ppm. FAB-MS (negative mode): m/z (%)
= 484
Complexes [NBu4]2[Pd2{C4(COOMe)4}2(μ-O–O)] [O–O = Chloran-
ilate (chl) (18) and Squarate (sq) (19)]: These dinuclear complexes
were obtained according to the following general method. To an
acetone solution (10 mL) of hydroxo complex (0.07 g, 0.054 mmol)
the stoichiometric amount of H(O–O) (molar ratio 1:1) was added.
The solution was stirred at room temperature for 30 min and the
solvent was partly evaporated under reduced pressure. The addition
of diethyl ether caused the formation of yellow-orange solids, which
were filtered off, washed with diethyl ether and air-dried. The com-
pounds were recrystallised from dichloromethane/diethyl ether.
[Pd{C4(COOMe)4}(2-pcal)]–.
[NBu4][Pd{C4(COOMe)4}(oxin)] (13): Yield 0.091 g (76%), m.p.
205 °C (dec.). C37H54N2O9Pd (777.25): calcd. C 57.2, H 7.0, N 3.6;
found C 57.3, H 7.2, N 3.6. IR (Nujol) ν = 1708 (vs), 1694 (vs),
˜
1570 (s), 1498 (s) cm–1. 1H NMR (200 MHz, CDCl3): δ = 3.64 (s,
3 H, COOMe), 3.65 (s, 3 H, COOMe), 3.81 (s, 3 H, COOMe), 3.86
(s, 3 H, COOMe), 6.77 (d, 1 H, oxin, J = 7.8 Hz), 6.84 (d, 1 H,
oxin, J = 7.0 Hz), 7.31 (m, 2 H, oxin), 8.10 (d, 1 H, oxin, J =
8.4 Hz), 8.33 (m, 1 H, oxin) ppm. 13C NMR (200 MHz, CDCl3): δ
= 50.9 (COOMe), 51.1 (COOMe), 51.2 (COOMe) ppm. FAB-MS
(negative mode): m/z (%) = 534 [Pd{C4(COOMe)4}(oxin)]–.
[NBu4]2[Pd2(C4{COOMe}4)2(μ-chl)] (18): Yield 0.057 g (72%), m.p.
215 °C (dec.). C62H96Cl2N2O20Pd2 (1473.2): calcd. C 50.5, H 6.6,
[NBu4][Pd{C4(COOMe)4}(2-pic)] (14): Yield 0.087 g (5%), m.p.
130 °C (dec.). C34H52N2O10Pd (755.20): calcd. C 54.1, H 6.9, N
N 1.9; found C 50.6, H 6.9, N 2.2. IR (Nujol) ν = 1703 (vs),
˜
1504 (vs) cm–1. 1H NMR (200 MHz, CDCl3): δ = 3.63 (s, 12 H,
COOMe), 3.76 (s, 12 H, COOMe) ppm. 13C NMR (200 MHz,
CDCl3): δ = 51.1 (COOMe), 51.2 (COOMe) ppm. FAB-MS (nega-
tive mode): m/z (%) = 1230 [(NBu4)Pd2{C4(COOMe)4}2(μ-chl)]–.
3.7; found C 54.1, H 7.1, N 3.9. IR (Nujol) ν = 1698 (vs), 1644 (vs),
˜
1600 (vs) cm–1. 1H NMR (200 MHz, CDCl3): δ = 3.62 (s, 3 H, CO-
OMe), 3.65 (s, 3 H, COOMe), 3.77 (s, 3 H, COOMe), 3.80 (s, 3 H,
COOMe), 7.44 (m, 1 H, 2-pic), 7.89 (m, 1 H, 2-pic), 8.15 (d, 1 H,
2-pic, J = 7.2 Hz), 8.35 (d, 1 H, 2-pic, J = 4.7 Hz) ppm. 13C NMR
(200 MHz, CDCl3): δ = 50.9 (COOMe), 51.0 (COOMe), 51.1 (CO-
OMe), 51.4 (COOMe) ppm. FAB-MS (negative mode): m/z (%) =
512 [Pd{C4(COOMe)4}(2-pic)]–.
[NBu4]2[Pd2(C4{COOMe}4)2(μ-sq)] (19): Yield 0.060 g (81%), m.p.
150 °C (dec.). C60H96N2O20Pd2 (1378.2): calcd. C 52.3, H 7.0, N
2.0; found C 52.4, H 7.2, N 2.2. IR (Nujol) ν = 1736 (vs), 1704 (vs),
˜
1556 (vs), 1494 s cm–1. 1H NMR (200 MHz, CDCl3): δ = 3.65 (s, 12
H, COOMe), 3.71 (s, 12 H, COOMe) ppm. 13C NMR (200 MHz,
CDCl3): δ = 51.2 (COOMe), 51.6 (COOMe) ppm. FAB-MS (nega-
tive mode): m/z (%) = 1138 [(NBu4)Pd2{C4(COOMe)4}2(μ-sq)]– +2;
895 [Pd2{C4(COOMe)4}2(μ-sq)]– + 1; 502 [Pd{C4(COOMe)4}-
(sq)]–.
Complexes [NBu4]2[Pd2{C4(COOMe)4}2(μ-az)] [az = Pyrazolate
(pz) (15), Triazolate (tz) (16) and 3,5-Dimethylpyrazolate (3,5-
Me2pz) (17)]: These dinuclear complexes were obtained according
to the following general method. To a solution of hydroxo complex
(0.07 g, 0.054 mmol) in dichloromethane (10 mL) was added the
corresponding azolate (molar ratio 1:2). The solution was stirred at
room temperature for 20 min and then concentrated under reduced
pressure until about one fifth of the initial volume. Slow addition
of diethyl ether caused the formation of yellow complexes, which
were filtered off, washed with diethyl ether and air-dried. The com-
pounds were recrystallised from dichloromethane/diethyl ether.
Complexes [NBu4][Pd{C4(COOMe)4}{S2P(OR)2}] [R: Me (20), Et
(21), iPr (22)]: To a solution of the precursor [NBu4]2[Pd2-
{C4(COOMe)4}2(μ-OH)2] (0.100 g, 0.077 mmol) in dichlorometh-
ane (10 mL) was added the corresponding ammonium dialkyldi-
thiophosphate (molar ratio 1:2). The solution was refluxed for
30 min and then concentrated under reduced pressure until ca. one
Eur. J. Inorg. Chem. 2005, 2360–2367
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© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2365

G. Sánchez, J. Vives, G. López, José L. Serrano, L. García, J. Pérez
FULL PAPER
fifth of the initial volume. Slow addition of diethyl ether caused the
formation of yellow complexes, which were filtered off, washed with
diethyl ether and air-dried. The compounds were recrystallised
from dichloromethane/diethyl ether.
N 3.6, S 8.2; found C 50.9, H 7.7, N 3.7, S 8.4. IR (Nujol) ν =
˜
1
1724 (vs), 1706 (vs), 1505 (vs) cm–1. H NMR (200 MHz, CDCl3):
δ = 1.19 (t, 6 H, Et), 3.60 (s, 6 H, COOMe), 3.67 (s, 6 H, COOMe),
3.74 (q, 4 H, Et) ppm. 13C NMR (200 MHz, CDCl3): δ = 12.4 (Et),
43.9 (Et), 50.8 (COOMe), 50.9 (COOMe) ppm. FAB-MS (negative
mode): m/z (%) = 539 [Pd{C4(COOMe)4}(S2CNEt2)]– + 1.
[NBu4][Pd{C4(COOMe)4}{S2P(OMe)2}] (20): Yield 0.099 g (82%),
m.p. 140 °C (dec.). C30H54NO10PPdS2 (790.27): calcd. C 45.6, H
6.9, N 1.8, S 8.1; found C 45.7, H 7.1, N 1.9, S 8.3. IR (Nujol) ν
˜
[NBu4][Pd{C4(COOMe)4}(S2CNPr2)] (24): Yield 0.086 g (69%),
m.p. 182 °C (dec.). C35H62N2O8PdS2 (809.43): calcd. C 51.9, H 7.7,
= 1698 (vs), 1022 (vs), 654 (vs) cm–1. 1H NMR (200 MHz, CDCl3):
δ = 3.61 (s, 6 H, COOMe), 3.69 (s, 6 H, COOMe), 3.70 (d, 6 H,
Me, JPH = 14.6 Hz) ppm. 31P NMR (200 MHz, CDCl3): δ = 109.3
N 3.5, S 7.9; found C 51.9, H 7.8, N 3.6, S 8.1. IR (Nujol) ν =
˜
1694 (vs), 1504 (vs) cm–1. 1H NMR (200 MHz, CDCl3): δ = 0.90
(t, 6 H, Pr), 1.64 (m, 4 H, Pr), 3.62 (m, 10 H, Pr + COOMe), 3.69
(s, 6 H, COOMe) ppm. 13C NMR (200 MHz, CDCl3): δ = 11.1
(Pr), 20.5 (Et), 50.8 (COOMe), 50.9 (COOMe), 51.1 (Pr) ppm.
FAB-MS (negative mode): m/z (%) = 566 [Pd{C4(COOMe)4}-
(S2CNPr2)]–.
(s, 1P) ppm. FAB-MS (negative mode): m/z (%)
= 547
[Pd{C4(COOMe)4}{S2P(OMe)2}]–.
[NBu4][Pd{C4(COOMe)4}{S2P(OEt)2}] (21): Yield 0.101 g (80%),
m.p. 128 °C (dec.). C32H58NO10PPdS2 (818.33): calcd. C 47.0, H
7.1, N 1.7, S 7.8; found C 47.1, H 7.4, N 2.0, S 8.1. IR (Nujol) ν
˜
= 1692 (vs), 1012 (vs), 652 (vs) cm–1. 1H NMR (200 MHz, CDCl3):
δ = 1.30 (t, 6 H, Et), 3.61 (s, 6 H, COOMe), 3.69 (s, 6 H, COOMe),
4.10 (m, 4 H, Et) ppm. 31P NMR (200 MHz, CDCl3): δ = 104.5 (s,
[NBu4][Pd{C4(COOMe)4}(S2CNC5H10)] (25): Yield 0.094 g (77%),
m.p. 165 °C (dec.). C34H58N2O8PdS2 (809.43): calcd. C 51.5, H 7.4,
N 3.5, S 8.1; found C 51.7, H 7.4, N 3.7, S 8.0. IR (Nujol) ν =
˜
1694 (vs), 1500 (vs) cm–1. 1H NMR (200 MHz, CDCl3): δ = 1.65
(m, 6 H, S2CNC5H10), 3.45 (s, 6 H, COOMe), 3.49 (s, 6 H, CO-
OMe), 3.85 (t, 4 H, S2CNC5H10) ppm. 13C NMR (200 MHz,
1P) ppm. FAB-MS (negative mode): m/z (%)
=
575
[Pd{C4(COOMe)4}{S2P(OEt)2}]–.
[NBu4][Pd{C4(COOMe)4}{S2P(OiPr)2}] (22): Yield 0.079 g (61%),
m.p. 143 °C (dec.). C34H62NO10PPdS2 (846.38): calcd. C 48.2, H
CDCl3):
δ = 15.2 (S2CNC5H10), 16.5 (S2CNC5H10), 38.6
(S2CNC5H10), 50.5 (COOMe), 50.7 (COOMe) ppm. FAB-MS
(negative mode): m/z (%) = 551 [Pd{C4(COOMe)4}(S2CNC5H10)]–
+ 1.
7.4, N 1.6, S 7.6; found C 48.4, H 7.5, N 1.9, S 7.9. IR (Nujol) ν
˜
= 1692 (vs), 1011 (vs), 645 (vs) cm–1. 1H NMR (200 MHz, CDCl3):
δ = 2.60 (d, 12 H, iPr, J = 6.2), 3.61 (s, 6 H, COOMe), 3.69 (s, 6 H,
COOMe), 4.74 (m, 2 H, iPr) ppm. 31P NMR (200 MHz, CDCl3):
δ = 101.1 (s, 1P) ppm. FAB-MS (negative mode): m/z (%) = 603
[Pd{C4(COOMe)4}{S2P(OiPr)2}]–.
[NBu4][Pd{C4(COOMe)4}(S2CNC4H8O)] (26): Yield 0.099 g
(82%), m.p. 186 °C (dec.). C33H56N2O9PdS2 (795.36): calcd. C 49.8,
H 7.1, N 3.5, S 8.1; found C 50.1, H 7.3, N 3.6, S 8.3. IR (Nujol)
ν = 1694 (vs), 1499 (vs) cm–1. 1H NMR (200 MHz, CDCl3): δ =
˜
Complexes [NBu4][Pd{C4(COOMe)4}(S2CNR2)] [R2NH: Et2NH
(23), Pr2 (24), Piperidine (25), Morpholine (26)]: In separate experi-
ments, to a solution of complex [NBu4]2[Pd2{C4(COOMe)4}2(μ-
OH)2] (0.100 g, 0.077 mmol) in acetone (10 mL) was added the cor-
responding amine (molar ratio 1:2) and a slight excess of carbon
disulfide. The solution was refluxed for 30 min and then concen-
trated under reduced pressure until ca. one fifth of the initial vol-
ume. Slow addition of diethyl ether caused the formation of yellow
complexes, which were filtered off, washed with diethyl ether and
air-dried. The compounds were recrystallised from dichlorometh-
ane/diethyl ether.
3.62 (s, 6 H, COOMe), 3.68 (m, 10 H, S2CNC4H8O + COOMe),
4.00 (t, 4 H, S2CNC4H8O) ppm. 13C NMR (200 MHz, CDCl3):
δ = 47.2 (S2CNC4H8O), 50.9 (COOMe) ppm. FAB-MS (negative
mode): m/z (%) = 552 [Pd{C4(COOMe)4}(S2CNC4H8O)]–.
Hydration of pyridine-2-carbonitrile: Complex [NBu4][Pd-
{C4(COOMe)4}(2-HNCOpy)] (27): To a solution of [NBu4]2-
[Pd2{C4(COOMe)4}2(μ-OH)2] (0.100 g, 0.077 mmol) in acetone/
H2O (10:0.5 mL) was added pyridine-2-carbonitrile (0.018 g,
0.154 mmol). The resultant clear solution was stirred for 30 min at
room temperature and then concentrated under reduced pressure
until ca. one fifth of the initial volume. Slow addition of diethyl
ether caused the formation of yellow complexes, which were filtered
[NBu4][Pd{C4(COOMe)4}(S2CNEt2)] (23): Yield 0.082 g (69%),
m.p. 132 °C (dec.). C33H58N2O8PdS2 (781.37): calcd. C 50.7, H 7.5,
Table 3. Crystal data and structure refinement for compounds 5, 8, 13, 20 and 27.
5
8
13
20
27
Formula
Molecular mass
Crystal system
Space group
a [Å]
b [Å]
c [Å]
C32H51N3O8PdS
744.22
monoclinic
P21/c
10.3174(6)
20.4166(16)
17.3615(19)
100.486(9)
3596.1(5)
4
C41H58N2O9Pd
829.29
monoclinic
P21/n
9.6870(10)
11.3580(10)
36.978(2)
91.78
4066.5(6)
4
C37H54N2O9Pd
777.22
monoclinic
P21/c
10.8804(6)
9.1196(5)
38.995(2)
95.3460(10)
3852.4(4)
4
C30H54NO10PPdS2
790.23
monoclinic
Cc
8.9363(7)
22.938(2)
18.9201(17)
102.281(6)
3789.4(6)
4
C34H53N3O9Pd
754.19
orthorhombic
Pcab
20.002(2)
17.359(3)
21.299(2)
90
7395.3(16)
8
β [°]
V [Å3]
Z
T [K]
173(2)
7028
0.624
173(2)
9782
0.511
100(2)
23503
0.535
173(2)
3566
0.692
173(2)
7553
0.556
Reflections collected
μ [mm–1]
Independent reflections 6324
7155
0.0335
8645
0.0405
2495
0.0631
6504
0.0633
Final R1
0.0328
wR2 [I Ͼ 2σ(I)]
R indices (all data)
0.0770
R1 = 0.0488
wR2 = 0.0823
0.0768
R1 = 0.0482
wR2 = 0.0814
0.0838
R1 = 0.0451
wR2 = 0.0859
0.1676
R1 = 0.0937
wR2 = 0.1916
0.1603
R1 = 0.1103
wR2 = 0.1767
2366
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
Eur. J. Inorg. Chem. 2005, 2360–2367

Reactivity of a Di-μ-hydroxo Complex with Protic Ligands
FULL PAPER
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recrystallised from acetone/diethyl ether.
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Complex [NBu4][Pd{C4(COOMe)4}(2-HNCOpy)] (27): Yield
0.091 g (78%), m.p. 123 °C. C34H53N3O9Pd (754.22): calcd. C 54.1,
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˜
1
1698 (vs), 1630 (vs), 1596 (vs), 1586 (vs), 1566 (vs) cm–1. H NMR
(200 MHz, CDCl3): δ = 3.63 (s, 6 H, COOMe), 3.76 (s, 3 H, CO-
OMe), 3.78 (s, 3 H, COOMe), 5.24 (br., 1 H, NH), 7.37 (m, 1 H,
2-HNCOpy), 7.87 (m, 1 H, 2-pic), 8.08 (m, 1 H, 2-HNCOpy), 8.38
(m, 1 H, 2-HNCOpy) ppm. 13C NMR (200 MHz, CDCl3): δ = 50.9
(COOMe), 51.0 (COOMe), 51.1 (COOMe), 51.3 (COOMe) ppm.
FAB-MS (negative mode): m/z (%) = 511 [Pd{C4(COOMe)4}(2-
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X-ray Structure Analysis: Suitable crystals of 5, 8, 13, 20 and 27
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Acknowledgments
Financial support of this work by Dirección General de Investiga-
ción (Spain) (project-BQU2001–0979-C02–01/02) is gratefully ac-
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Received: December 22, 2004
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www.eurjic.org
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2367