NMR spectroscopic studies of palladium(II) complexes of bidentate diphenylphosphane ligands With acetate and tosylate anions: complex formation and structures

Article abstract of DOI:10.1002/ejic.200900974

The synthetic pathways towards Pd¹¹ complexes of functionalized bidentate diphenylphosphane ligands of the type [Pd(ligand) (anion)₂] and [Pd(ligand)₂](anion)₂ have been investigated. Eighteen different ligands have been used in combination with strongly (acetate, OAc^-) or weakly (tosyl-ate, OTs^-) coordinating anions. The solid-state structure of some representative complexes was determined with X-ray crystallography. It is shown that the solid-state structures are fully retained in solution. The formation of [Pd(ligand)-(anion)₂]-type complexes was studied in detail by ¹H- and ³¹P-NMR spectroscopy. Depending on the ligand structure, the complex is formed instantaneously, via a polynuclear intermediate or is not formed at all. Complex formation is demonstrated to depend on the length and rigidity of the ligand backbone and on the steric bulk at the ortho position, of the phenyl rings on phosphorus. It was also found, that the coordinating ability of the anions can alter the structure of the kinetic and/or thermodynamic product.

Full text of DOI:10.1002/ejic.200900974

FULL PAPER
DOI: 10.1002/ejic.200900974
NMR Spectroscopic Studies of Palladium(II) Complexes of Bidentate
Diphenylphosphane Ligands with Acetate and Tosylate Anions: Complex
Formation and Structures
Tiddo J. Mooibroek,[a] Elisabeth Bouwman,*[a] Martin Lutz,[b] Anthony L. Spek,[b] and
Eite Drent[a]
Keywords: Palladium / P ligands / NMR spectroscopy / Complex formation / Anions
The synthetic pathways towards PdII complexes of function-
alized bidentate diphenylphosphane ligands of the type
[Pd(ligand)(anion)2] and [Pd(ligand)2](anion)2 have been in-
vestigated. Eighteen different ligands have been used in
combination with strongly (acetate, OAc–) or weakly (tosyl-
ate, OTs–) coordinating anions. The solid-state structure of
some representative complexes was determined with X-ray
crystallography. It is shown that the solid-state structures are
fully retained in solution. The formation of [Pd(ligand)-
(anion)2]-type complexes was studied in detail by 1H- and
31P-NMR spectroscopy. Depending on the ligand structure,
the complex is formed instantaneously, via a polynuclear in-
termediate or is not formed at all. Complex formation is dem-
onstrated to depend on the length and rigidity of the ligand
backbone and on the steric bulk at the ortho position of the
phenyl rings on phosphorus. It was also found that the coor-
dinating ability of the anions can alter the structure of the
kinetic and/or thermodynamic product.
been reported that the catalytic performance of in situ
formed catalysts may be inferior to that of the preformed
catalysts.[23]
It has also been reported that when [Pd(OAc)2] and an
equimolar amount of dppe [1,2-bis(diphenylphosphanyl)-
ethane] are dissolved in CD3OD, initially the catalytically
inactive complex [Pd(dppe)2](OAc)2 is formed; only after
standing for about 24 h, the catalytically active species
[Pd(dppe)(OAc)2] is obtained.[3]
To the best of our knowledge, there is no simple way to
predict the exact kinetic pathway by which a certain ligand
will or will not form the desired [Pd(diphosphane)-
(anion)2]-type complex. We therefore set out to determine
the influence of the bridging groups and substituents in che-
lating diphosphane ligands (see Table 1) on the kinetics and
the result of complex formation. Furthermore, the role of
the anion in the complex formation process was investigated
by using acetate (strongly coordinating) and tosylate
(weakly coordinating) anions. Prior to this, however, the
synthesis of this type of complexes is reported, followed by
their structural characteristics in the solid phase and in
solution.
Introduction
For some decades, PdII-diphosphane catalytic systems
have enjoyed much attention, both from academia and in-
dustry. Especially the copolymerization of CO and ethene
has been widely studied[1,2] and applied [Carilon®(Shell)
and Ketonex® (BP)] using such catalytic systems. A reac-
tion, in which these palladium catalysts are relatively po-
orly studied, is the carbonylation of nitroaromatic mole-
cules to aromatic isocyanates.[4–9] For this reaction most
endeavours involve catalysts of the type [PdII(1,10-phenan-
throline)2](anion)2,[5–19] and only few involve catalysts of
the type P2PdII.[5,17,20,21] Because there is no fundamental
reason why N2PdII complexes should perform better than
P2PdII complexes, we are studying these palladium-phos-
phane complexes in the carbonylation of nitrobenzene. In
many catalytic studies the catalyst is often formed in situ
by mixing a palladium(II) salt with a diphosphane ligand
in methanol, assuming that the desired [Pd(diphosphane)-
(anion)2]-type complexes are actually formed. However,
complex formation is not always a trivial process. For ex-
ample, for the copolymerization of CO and ethene it has
[a] Leiden Institute of Chemistry, Gorlaeus Laboratories, Univer-
sity of Leiden,
Results and Discussion
P. O. Box 9502, 2300 RA Leiden, The Netherlands
Fax: +31-71-527-4671
E-mail: bouwman@chem.leidenuniv.nl
[b] Bijvoet Center for Biomolecular Research, Crystal and Struc-
tural Chemistry, Utrecht University,
Complex Synthesis
Starting from crystalline [Pd3(OAc)6],[24] four solvents
were employed in the complex synthesis. In order of in-
creasing polarity these are: CHCl3, CH2Cl2, (CH3)2CO and
Padualaan 8, 3584 CH Utrecht, The Netherlands
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.200900974.
298
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2010, 298–310

PdII Complexes of Bidentate Diphenylphosphane Ligands
Table 1. Schematic representation of the ligands used in this study.
The inset figures show the general structures.
Figure 1. Schematic overview of the synthetic methods to form the
monochelate complex [Pd(ligand)(anion)2] or the bischelate com-
plex [Pd(ligand)2](anion)2 with acetate or tosylate anions.
formed immediately. However, after standing for two min-
utes, a yellow precipitate formed, which turned red-brown
over time. The isolated solid proved to be insoluble in a vast
variety of different solvents, indicating that this solid is a
coordination polymer. When a solution of Pd(OAc)2 was
added to L16, a mixture of species was formed (several 31P
resonances), which did not change over time. No attempts
were made to further characterize these compounds.
Not all complexes were isolated and fully characterized;
some were only detected in situ during the NMR spectro-
scopic studies. Nevertheless, for convenience, in Table S1
(Supporting Information) the proton and phosphorus reso-
nances of all the palladium complexes that could be mea-
sured are summarized. The monochelate complexes are
indicated as MxA or MxT with ligand Lx and coordinating
acetate or tosylate anions, respectively, whereas the bischel-
ate complexes are indicated as BxA or BxT with ligand Lx
and non-coordinating acetate or tosylate anions.
CH3OH. The methods by which the desired complexes can
successfully be obtained are summarized schematically in
Figure 1. However, some difficulties were encountered in
the synthesis and isolation of these complexes. Dry and de-
gassed solvents must be used as too much water generally
hampered the isolation due to the formation of an oil and
partial oxidation of the ligand. Furthermore, the flasks
were wrapped in foil; the absence of light in most cases
prevented plating of Pd0. The choice of the solvent ap-
peared to be most important. CHCl3 must be avoided since
severe plating was usually observed when working with this
solvent. CH2Cl2 and (CH3)2CO were best suited for the syn-
thesis of the monochelate [Pd(ligand)(anion)2]-type com-
plexes. Methanol is the only solvent in which the bischelate
[Pd(ligand)2](OAc)2-type complexes can be synthesized; the
other solvents are not polar enough to sufficiently dissoci-
Complex Structures in the Solid State
Light yellow transparent single crystals of the com-
ate the OAc– anions. The bischelate complexes [Pd(ligand)2]- pounds [Pd(L2)(OAc)2] (M2A), [Pd(L7)(OAc)2] (M7A),
(OTs)2 can be prepared in all four solvents.
[Pd(L10)(OAc)2] (M10A), [Pd(L13)(OAc)2] (M13A), and
Not all complexes form instantaneously. Indeed, in some [Pd(L10)2](OTs)2 (B10T) were obtained using the solvent
cases the desired complex is formed only after several hours diffusion technique. The crystal structures were determined
(∆t, see complex formation studies for details). Therefore, by X-ray diffraction; crystallographic data and details of
depending on the ligand, the reaction mixture should stand the structure refinement are given in Table 4. Perspective
for an appropriate amount of time (usually overnight), as views of the molecular structures of M10A and B10T in the
otherwise a mixture of species may be isolated.
crystal are shown in Figure 2. Because the global structures
Once the monochelate or bischelate complex had been of the monochelate complexes are very similar, projections
formed with the acetate anions, addition of two equivalents of the complexes M2A, M7A and M13A can be found in
of p-toluenesulfonic acid resulted in the quantitative re- the Supporting Information. Selected bond lengths, angles
placement of the anions in any of the solvents, as evidenced and torsion angles are listed in Table 2.
by the appearance of a peak around 1.0 ppm for acetic acid.
Complexes M2A and B10T are located on twofold rota-
The 1,4-butyl-bridged ligands present a special case. tion axes, respectively, running through the palladium cen-
When applying the procedure of Mul and co-workers,[3] the tre and the central carbon atom(s) of the ligand backbone.
unsubstituted ligand L14 yielded the monochelate complex. Hence, M2A has only one unique phosphorus atom, and
This was not the case for L15 and L16. When a solution of B10T only two. The palladium centres in the complexes
Pd(OAc)2 was added to L15, a clear yellow solution was M2A, M7A, M10A, M13A, and B10T are in distorted
Eur. J. Inorg. Chem. 2010, 298–310
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
299

T. J. Mooibroek, E. Bouwman, M. Lutz, A. L. Spek, E. Drent
FULL PAPER
Figure 2. Displacement ellipsoid plots (50% probability level) of (a) [Pd(L10)(OAc)2] (front view), (b) cation of [Pd(L10)2](OTs)2 (top
view), (c) cation of [Pd(L10)2](OTs)2 (front view along the twofold axis, one ligand omitted, except for the phosphorus atoms). Hydrogen
atoms, uncoordinated anions and uncoordinated solvent molecules are omitted for clarity. Symmetry operation i: 1 – x, y, 0.5 – z.
square-planar geometries with cis-P2O2 donor sets for the [between 2.71 (M13A) and 3.06 Å (B10T)], and the Pd–P–
monochelate complexes and a P4 donor set for the bis- C–C torsion angles [between 1.38(18)° (M10A) and 11.5(3)°
chelate complex. The Pd–P and Pd–O distances can be con- (M13A)] of the observed anagostic interactions, can be con-
sidered as normal.[25] Although the acetate anions are coor- sidered as normal.[28] Furthermore, relatively strong intra-
dinated in a monodentate fashion, they may be considered molecular C–H···π interactions between the ortho protons
pseudo-chelating with their second O-atom at distances to of the equatorial rings (H502, H602, H702) and one π-bond
Pd ranging between 2.8067(19) (M7A) and 3.1771(16) of the axial rings (C101/C106, C201/C206, C301/C306) are
(M10A) Å, and Pd–O–C angles ranging between 67.53(18)° observed.[29] The various H···C distances, ranging between
(M13A) and 75.65(14)° (M10A). The magnitude of the dis- 2.527 (for M10A) and 2.817 (for M7A) Å, are well within
tortion from the ideal square-planar geometry varies con- the sum of the van der Waals radii of H and C (2.90 Å).
siderably. The dihedral angle between the P–Pd–P and X–
The structures of the complexes [Pd(L1)OAc2],[30]
Pd–X (X = P or O) planes range from 1.56(7)° in M2A, to [Pd(L2)Cl2] and [Pd(L7)Cl2],[31] as well as of the analogous
7.22(8)–10.46(6)° in M7A, M10A, and M13A, and is nickel(II) complexes [Ni(L2)I2][26] and [Ni(L7)Cl2][32] have
19.78(5)° in the bischelate complex B10T. The large tetrahe- been published; the reported distances, angles and Pd···H
dral distortion in B10T is due to the presence of large steric or Ni···H interactions are comparable to those described
bulk of two ligands around the palladium centre; there are above.
no other intermolecular or intramolecular contacts respon-
sible for this distortion. The ligand bite angles also vary
considerably. The ethylene-bridged ligand L2 in M2A has a
bite angle of 85.98(3)°, whereas the propylene-bridged li-
gand L7 in M7A has a bite-angle of 95.497(19)°. This angle
Complex Structure in Solution
1
As typical examples, the H NMR spectra of the mono-
is slightly compressed by the addition of steric bulk to the chelate complexes M13A and M13T are shown in parts a
backbone, resulting in 90.62(2)° in M10A and 92.22(3)° in and c of Figure 3, respectively [in (CD3)2CO]. In the solid-
M13A. In the bischelate complex B10T, the angle is com- state structures, the two phenyl rings on each phosphorus
pressed even further to a mere 85.69(4)°. The six-membered atom are distinct with respect to their orientation to the
PdP2C2 coordination rings in M10A, M13A, and B10T plane of coordination and have been labelled as axial or
have a twist-boat and in M7A a screw-boat conformation, equatorial. In solution at room temperature, however, only
while the five-membered PdP2C ring in M2A has a half- one set of resonances is observed, as is shown in Figure 3a
chair conformation.
for M13A. The observation that the two phenyl rings ap-
It is possible to distinguish the two aryl rings on each pear to be equivalent in solution is due to dynamic flipping
phosphorus atom as oriented either axially (for the NMR of the backbone.[26] When this flipping is frozen at low tem-
spectroscopic discussion denoted as rings 100, 200, 300, and perature, the axial and equatorial protons become inequiva-
400) or equatorially (rings 500, 600, 700, and 800) with re- lent; two sets of proton resonances are observed in 1H
spect to the chelate ring of the bidentate ligand (see for NMR spectra (Figure 3, b). The proton resonances of the
example rings 100 and 500 in Figure 2, a and c). The axial axial phenyl rings are relatively deshielded due to the Pd···H
phenyl rings are held in place by Pd···H interactions be- interactions, whereas the proton resonances of the equato-
tween its ortho proton and the filled palladium dz2 orbital. rial phenyl rings are shielded due to the H···Cπ interactions.
Similar interactions have been reported for related nickel
For the monochelate complex M13T with the weakly-
and palladium complexes.[26,27] These interactions have coordinating OTs– anions (Figure 3, c) a different phenome-
been described as anagostic,[28] and are characterized by a non is observed upon cooling; the peaks are not split, but
Pd–P–C–C torsion angle close to 0°. The Pd···H distances broadened (Figure 3, d). It suggests that the weakly-coordi-
300
www.eurjic.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2010, 298–310

PdII Complexes of Bidentate Diphenylphosphane Ligands
Table 2. Selected interatomic distances, angles, and other relevant geometric data for complexes M2A, M7A, M10A, M13A, and B10T.
Complex:
M2A[a]
M7A
M10A
M13A
B10T[a]
(pseudo) coordination (Å)
Pd1–P1
2.2177(6)
2.2223(6)
2.2273(5)
2.2366(6)
2.2305(5)
2.2341(8)
2.2254(8)
2.4091(8)
2.3938(9)
Pd1–P2
Pd1–P3
Pd1–O31
Pd1–O41
Pd1–O32
Pd1–O42
2.0984(14)
2.9169(17)
2.1112(14)
2.0946 (13)
2.8662(19)
2.8067(19)
2.0891(13)
2.0936(15)
3.1771(16)
3.0718(16)
2.047(2)
2.064(2)
3.099(2)
3.153(2)
Anagostic interactions [Å][b]
Pd1···H102
Pd1···H202
Pd1···H302
2.75
2.72
2.69
2.87
2.75
2.82
2.71
3.03
3.06
C–H···π interactions [Å][b]
H502···C101
2.57
2.77
2.70
2.82
2.61
2.59
2.53
2.53
2.55
2.66
2.59
2.72
2.54
2.68
2.66
2.63
2.67
2.82
H502···C106
H602/702···C201/301
H602/702···C206/306
Angles [°]
P3–Pd1–P3Ј
86.04(3)
95.71(3)
166.56(3)
85.69(4)
P1–Pd1–P3
P1–Pd1–P3Ј
P1–Pd1–P2/1Ј
O31–Pd1–O41/31Ј
P1–Pd1–O41
P2–Pd1–O42
P1–Pd1–O41/31Ј
P2–Pd1–O31
Pd1–O31–C31
Pd1–O41–C41
Pd1–O32–C31
Pd1–O42–C41
85.98(3)
92.22(8)
90.91(5)
95.497(19)
87.03(5)
90.78(4)
90.62(2)
92.20(6)
90.38(4)
87.70(4)
170.96(4)
174.09(4)
121.81(13)
117.96(14)
68.60(12)
70.89(13)
92.22(3)
94.97(9)
87.00(6)
86.24(6)
172.80(6)
176.36(6)
117.90(18)
120.6(2)
67.53(18)
68.40(18)
87.14(4)
176.69(4)
111.28(14)
73.80(14)
174.80(4)
171.72(4)
108.29(13)
107.86(12)
74.79(14)
75.65(14)
Dihedral angles between the PdP2 and the PdX2 planes (°)
PdP2–PdX2 (dihedral) 1.56(7), X = O 7.22(8), X = O
10.46(6), X = O
7.63(9), X = O 19.78(5), X = P
Cremer–Pople ring puckering parameters for the PdP2C2 and PdP2C rings[c]
Ring 1
Ring 2
Q2 [Å]
Q3 [Å]
θ [°]
0.492(2)
0.5247(19)
0.3266(19)
58.09(18)
156.4(2)
0.8588(17)
–0.0369(16)
92.46(11)
0.812(2)
0.051(2)
86.42(14)
82.57(16)
0.906(3)
0.000(2)
90.00(13)
0.898(3)
0.000(3)
90.00(19)
φ2 [°]
270.00(12)
–7.1(2)
266.99(11)
270.00(14) 270.00(14)
Torsion angles (°)
Pd1–P1–C101–C102
Pd1–P2–C201–C202
Pd1–P3–C301–C302
Pd1–P1–C501–C502
Pd1–P2–C601–C602
Pd1–P3–C701–C702
–4.95(18)
–5.67(19)
–1.38(18)
–1.8(2)
11.5(3)
8.3(3)
6.1(3)
13.0(3)
120.0(3)
102.30(18)
–104.51(18)
–102.44(17)
105.15(18)
104.54(17)
–113.0(3)
–108.1(3)
101.7(3)
[a] Coordination rings are located on twofold axis. [b] Hydrogen atoms were introduced in calculated positions based on a C–H distance
of 0.95 Å. [c] Cremer–Pople ring puckering parameters for the PdP2C2 and PdP2C rings.[22]
nating OTs– anions are displaced with solvent molecules; of relatively strongly coordinating OAc– anions in M13A
the PdII ion is in a [Pd(ligand)(solvent)2]2+ coordination makes the overall complex more rigid at lower temperature,
sphere and even at low temperatures the coordinated sol- thereby hindering the dynamic flipping of the backbone.
vent ligands are quickly exchanged with other solvent mole- In the case of the crowded [Pd(ligand)2](anion)2 comp-
cules, thus decreasing the steric hindrance for the flipping of lexes, two sets of proton resonances are observed at all tem-
the backbone. Further cooling should result in a complete peratures. Their spectra resemble the one shown in Fig-
splitting into two sets of protons. In contrast, the presence ure 3, b.
Eur. J. Inorg. Chem. 2010, 298–310
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
301

T. J. Mooibroek, E. Bouwman, M. Lutz, A. L. Spek, E. Drent
FULL PAPER
or CD2Cl2 (Entries 1–3). In CD3OD however, as reported
by Mul and co-workers,[3] L1 initially forms the bischelate
complex (δP = 58.7 ppm) as the kinetic product, which con-
verts to the thermodynamically more stable monochelate
complex (δP = 63.7 ppm) over time (kЈ = 0.44 h–1). In the
case of the sterically more demanding ligands L2 (o-MeO)
and L3 (o-EtO), in CD3OD the monochelate complex is
formed directly as the major species (≈ 70%). The other
product is the bischelate complex (≈ 30%). The composi-
tion of this mixture did not change over time (eight hours),
nor upon addition of another 0.2 equiv. of Pd(OAc)2. This
indicates that the o-MeO moieties on the ligand shield the
palladium in the bischelate complex from OAc– coordina-
tion. It thus appears that ethylene-bridged ligands directly
form the monochelate complex, except in a relatively polar
solvent. Only then the OAc– anions may dissociate from
PdII to allow a second ligand to coordinate, thus forming
the bischelate complex. Indeed, it has been reported that by
employing the weakly coordinating OTs– anions, the bi-
schelate complex is formed exclusively.[3]
Propylene-Bridged Ligands
For the ligands with an unsubstituted propylene back-
bone (Entries 4 and 6–9) different behaviour is observed
when starting from Pd(OAc)2. In the case of L4 (dppp), the
monochelate complex is formed immediately in all solvents.
However, the ortho-methoxy analogue of this ligand (L7)
forms the monochelate complex via an intermediate species,
as is illustrated in Figure 4 (in CD2Cl2).
Figure 3. 1H NMR spectra of monochelate complexes in (CD3)2-
CO: a) M13A at 23 °C; b) M13A at –60 °C; c) M13T at 23 °C; d)
M13T at –60 °C; e) schematic view of the interactions and labelling
of the H atoms. The symbol ᭹ indicates that the resonance belongs
to an equatorially aligned ring, o indicates that the resonance be-
longs to an axially aligned ring, and # indicates a resonance from
a tosylate anion.
This intermediate is not the usual bischelate complex,
since the characteristic resonances of the axial and equato-
rial (ortho) protons are not observed. In the NMR spectra
of this intermediate, no free ligand 31P resonance is ob-
served at –37 ppm, and several resonances are observed for
the ortho-methoxy protons (3.3–3.9 ppm). The resonances
around 1.8 and 0.6 ppm are indicative of different types of
OAc– anions. These observations suggest the formation of
a polynuclear species, which could be either a polymeric
compound [Pd(L7)(OAc)2]n in which the ligand is mono-
dentate and bridging, or a dinuclear complex [{Pd(L7)-
(OAc)}2L7](OAc)2. The intermediate species could be iso-
lated, but we were unable to detect a mass higher than that
of the monochelate complex using ESI mass spectroscopy.
To investigate whether the difference in behaviour of the
ligands L4 and L7 is due to steric or electronic reasons, a
series with increased steric bulk on the ortho position was
studied; L4 (H), L6 (Me), L7 (MeO), and L8 (EtO). The
same type of intermediate is observed for the ligands L6–L8
in (CD3)2CO; the conversion to the monochelate complex
follows approximate first-order kinetics (see Figure 5). An
increase in steric bulk results in a lower p Ǟ m conversion
rate, with kЈ = 1.03, 0.49, and 0.25 h–1 for L6, L7, and L8,
respectively. Apparently, in the proposed intermediate poly-
Complex Formation Studies
NMR spectroscopic studies were performed to explore
the kinetics of formation of the palladium complexes of dif-
ferent types of ligands in more detail. Using Pd(OAc)2, the
complex formation was studied in the deuterated solvents
CD2Cl2, (CD3)2CO, and CD3OD. When using Pd(OTs)2 the
only suitable solvent is a mixture of (CD3)2CO in CD2Cl2
(17% v/v); Pd(OTs)2 is immediately reduced in CD3OD,
HOTs and Pd(OTs)2 are insoluble in pure CD2Cl2, and
most [Pd(ligand)2](OTs)2-type complexes are insoluble in
(CD3)2CO. An overview of the results of selected complex
formation studies is presented in Table 3. During these
studies a variety of complexes were observed in situ, but
1
were not isolated. Nonetheless, an overview of the H- and
31P-NMR spectroscopic data of all the detected complexes
is given in Table S1.
Ethylene-Bridged Ligands
Use of the ethylene-bridged ligands L1–L3 directly re- nuclear species, the larger steric “ortho-bulk” of the ligand
sults in the formation of the monochelate complex [Pd(li- shields the palladium dz2 orbital (see also Figure 3, e) for
gand)(OAc)2] when the reaction is performed in (CD3)2CO the approach of a phosphane (in the case of [Pd(L)-
302
www.eurjic.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2010, 298–310

PdII Complexes of Bidentate Diphenylphosphane Ligands
1
Table 3. Overview of complex formation studies, monitored by H and 31P NMR spectroscopy.[a]
[a] [Pd(OAc)2] or [Ligand] = 16 m. The values between parentheses represent a reaction constant (kЈ in h–1, see Exp. Sect.) for the
observed conversion. m = monochelate complex; b = bischelate complex; p = polynuclear complex; x = unidentified complex(es); i =
ligand or complex is insoluble. See text for further explanation. [b] 17% (v/v) of (CD3)3CO in CD2Cl2 was actually used due to solubility
problems. [c] The complex formation was accompanied by plating over time.
1
Figure 4. Complex-forming study followed by H and 31P NMR spectroscopy; [Pd(OAc)2] in CD2Cl2 added to L7. ᭹ resonance of the
(thermodynamic) monochelate complex; ᭺ resonance of the (kinetic) intermediate.
(OAc)2]n) or an acetate anion (in the case of
Interestingly, when the propylene backbone is more rigid
[{Pd(L)(OAc)}2L](OAc)2). This is illustrated in Figure 6. To by the gem-dialkyl substitution of the central carbon atom
confirm that the effect is purely based on steric grounds the in the bridge (L10 – L13, Entries 10–13), no intermediate
experiment was repeated with L9 (p-MeO, Entry 9). This species is observed. In these cases the monochelate complex
ligand indeed showed the immediate formation of the mon- is immediately formed, even for ligand L12, which com-
ochelate complex in all three solvents.
prises the larger o-EtO substituent on the phenyl rings. This
Eur. J. Inorg. Chem. 2010, 298–310
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
303

T. J. Mooibroek, E. Bouwman, M. Lutz, A. L. Spek, E. Drent
logues. A number of resonances is observed in the 31P
FULL PAPER
1
NMR spectrum around 11 ppm, and in the H NMR spec-
trum around 3.75 ppm for the methoxy group. Especially
the aromatic resonance around 7.9 ppm is very characteris-
tic for this type of intermediate. However, for L15 and L16
the nature of the thermodynamic product is unclear; it is
most certainly not the desired monochelate complex, or the
bischelate complex. The rate of conversion again depends
on the size of the steric bulk; kЈ = 1.26 (L15; o-MeO) and
0.58 (L16; o-EtO). Because L17 (p-MeO) eventually forms
the monochelate complex, the formation of the unidentified
species is ascribed to steric influences. When the backbone
is made more rigid (L19), the monochelate complex is
formed immediately and none of the other species were de-
tected.
Figure 5. Effect of the steric bulk on monochelate complex forma-
tion with propylene-bridged ligands in acetone; plot of ln(rel. inte-
gral) vs. time (h), at 23 °C with linear trend lines. ᭛ L6 at δ =
8.1 ppm; ᭺ L7 at δ = 7.4 ppm; ᮀ L8 at δ = 7.3 ppm.
Figure 6. Illustration of the ligand-induced steric hampering that
retards the formation of [Pd(L)(OAc)2]-type complexes. The steric
bulk of the ortho-moieties (X) of the ligand shields the palladium
2
dz orbital from ligand approach in [Pd(L)(OAc)2]n (a), or from
acetate coordination in [{Pd(L)(OAc)}2L](OAc)2 (b).
observation is attributed to the so-called “Thorpe–Ingold”
effect;[33,34] due to the presence of the two substituents on
the central carbon atom in the backbone, the two phospho-
rus atoms are pre-oriented and more likely to form a chelate
on palladium. In line with this, L5 also forms the mono-
chelate complex immediately.
Figure 7. Complex formation for L15 monitored by 1H- and 31P
NMR spectroscopy; [Pd(OAc)2] in CD2Cl2 added to L15. ᭹ reso-
nance of thermodynamic product; ᭺ resonance of the kinetic inter-
mediate.
Butylene-Bridged Ligands
With the butylene-bridged ligands L14 and L17 (o-H and
p-MeO, Entries 14 and 17) the monochelate complex is
formed only via an intermediate species; several 31P reso-
nances around 12 ppm disappear over the time. The ap-
proximate first-order reaction constants of these conver-
sions are of the same magnitude (in CD2Cl2 kЈ = 1.07 and
1.15 h–1 for L14 and L17, respectively). This difference in
The Role of the Coordinating Strength of the Anions
Not only the steric bulk and (the rigidity of) the ligand
behaviour between the unsubstituted C3- and C4-bridged backbone are important for the course and rate of the com-
ligands is ascribed to the increased flexibility of the butyl- plex formation. The coordination strength of the anions
ene backbone. This renders the ligand a weaker chelate thus was also found to be an important factor. For L1 (ethylene
favouring the initial formation of a polynuclear species. In backbone) it is known that when employing the weakly co-
agreement with this hypothesis, using a ligand with a more ordinating CF3C(O)O– anions in CD3OD, the bischelate
rigid backbone (L18, Entry 18) the monochelate complex is complex is both the kinetic and thermodynamic species.[3]
formed immediately.
For the propylene-bridged ligands, it was found that the
A different thermodynamic species is observed when ste- more polar the solvent, the more dissociated the OAc–
ric bulk is added to the ortho position in the flexible butyl- anions become, and hence the slower the conversion to the
ene-bridged ligands (L15 and L16). This is exemplified for monochelate complex. This is most prominently reflected
ligand L15 in Figure 7. The kinetic product is rather similar in the series performed with L7 (o-MeO). As can be seen
to those formed for the o-H (L14) and p-MeO (L17) ana- from Entry 7 in Table 4, the monochelate complex is
304
www.eurjic.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2010, 298–310

PdII Complexes of Bidentate Diphenylphosphane Ligands
Table 4. Details of the X-ray crystal structure determinations.
[Pd(L2)(OAc)2]
[Pd(L7)(OAc)2]
[Pd(L10)(OAc)2]
[Pd(L13)(OAc)2]
[Pd(L10)2](OTs)2
Empirical formula
C34H38O8P2Pd·2CHCl3 C35H40O8P2Pd·H2O
C37H44O8P2Pd·3H2O C43H52O10P2Pd
[C66H76O8P4Pd] (C7H7O3S)2
+ disordered solvent
1569.92[a]
Fw
981.72
775.03
839.11
897.19
Crystal colour
Crystal size [mm]3
Crystal system
Space group
a [Å]
colourless
0.21ϫ0.15ϫ0.12
monoclinic
C2/c (no. 15)
21.3571(2)
11.0576(1)
19.5445(2)
116.1887(4)
4141.78(7)
4
yellow
colourless
0.30ϫ0.12ϫ0.08
monoclinic
P21/c (no. 14)
13.7552(1)
14.2919(1)
20.0689(2)
96.4044(4)
3920.68(6)
4
yellow
yellow
0.24ϫ0.18ϫ0.15
monoclinic
P21/c (no. 14)
13.9845(3)
16.2664(4)
20.0199(3)
130.991(2)
3437.47(16)
4
0.66ϫ0.12ϫ0.12
monoclinic
P21/c (no. 14)
10.8518(4)
26.8681(11)
15.5000(7)
113.881(3)
4132.4(3)
4
0.30ϫ0.12ϫ0.12
monoclinic
C2/c (no. 15)
26.4819(3)
14.1198(2)
24.7120(3)
118.1165(6)
8149.85(18)
4
b [Å]
c [Å]
β [°]
V [Å3]
Z
dcalcd. [g/cm3]
µ [mm–1]
(sin θ/λ)max [Å–1]
1.574
0.961
0.65
1.498
0.687
0.65
1.422
0.612
0.65
1.442
0.584
0.65
1.279
0.417
0.60
Refl. (meas./unique) 33907/4746
58871/7906
multi-scan
0.75–0.90
438/0
0.0257/0.0579
0.0400/0.0637
1.044
55912/8984
multi-scan
0.92–0.96
470/0
0.0314/0.0722
0.0470/0.0797
1.067
136182/9451
multi-scan
0.60–0.93
511/0
0.0409/0.0745
0.0676/0.0856
1.152
37289/7346
multi-scan
0.74–0.96
Abs. corr.
multi-scan
0.85–0.89
270/66
0.0299/0.0731
0.0436/0.0793
1.100
Abs. corr. range
Param./restraints
R1/wR2 [IϾ2σ(I)]
R1/wR2 [all refl.]
S
464/0
0.0463/0.1129
0.0685/0.1222
1.031
∆ρmin./max. [eÅ–1]
–0.54/0.51
–0.43/0.60
–0.68/0.84
–0.71/0.57
–0.59/0.95
[a] Derived values do not contain the contribution of the disordered solvent.
formed slightly faster in CD2Cl2 (kЈ = 0.53) than in (CD3)2- vs. 94°).[35] This imposes a steric constraint on the adjacent
CO (kЈ = 0.49), and only very slowly in CD3OD (kЈ = 0.07). coordination sites,[36,37] thus disfavouring bischelate com-
Similar trends were observed with ligands L6 and L8 (En- plex formation.
tries 6 and 8). That these observations are due to the coor-
dinating ability of the anions is confirmed by employing
weakly-coordinating OTs– anions. Instead of a polynuclear
Conclusions
species, L7 now forms the bischelate complex as kinetic
product (Entry 7). Evidently, OTs– anions are highly disso-
A variety of palladium complexes with substituted biden-
ciated (even in the relatively apolar CD2Cl2) to allow the tate diphenylphosphane ligands has been synthesized using
formation of a cationic species with a P4 donor set. The straightforward synthetic procedures. More specifically,
conversion to the monochelate complex is extremely slow monochelate and bischelate complexes with strongly (OAc–)
(kЈ = 0.01 h–1), because the o-MeO moieties shield the pal- or weakly (OTs–) coordinating anions have been obtained,
ladium dz2 orbitals from anion coordination (see Figure 6). and structures of representative complexes have been de-
Evidently, OTs– anions coordinate so weakly that they can scribed. By using variable-temperature NMR spectroscopic
hardly overcome this steric repulsion induced by the o-MeO studies, it was shown that the solid-state structure of this
moieties. When working with L4 (o-H, Entry 4), the bischel- type of complexes is fully retained in solution.
ate complex was also formed as intermediate. However, due
to the smaller ortho-bulk the conversion to the monochelate a crucial role in the formation of [Pd(ligand)(anion)2]-type
complex proceeds very rapidly (kЈ = 6.23 h–1).
complexes: the length of the bridge between the phosphorus
It was shown that three ligand-dependent factors play
The coordinating ability of the anions also influences the donors, the steric bulk at the ortho position of the phenyl
course of the complex formation with butylene-bridged li- rings, and the rigidity of the backbone. The coordinating
gands. As can be seen in Entry 14 (L14, o-H), when em- ability of the anions was also found to be an important
ploying OTs– anions the monochelate complex is formed factor in the complex forming process.
immediately, whereas with OAc– anions it proceeds via
Depending on these factors, the desired [Pd(ligand)(-
some intermediate. This can be rationalized as follows. anion)2] complex is formed instantaneously, via some inter-
When OAc– anions are used, the monochelate complex mediate, or not at all. Notably, when making the ligand
(P2O2 donor set) is formed via a PO3 donor set. This is bridge more rigid, the desired [Pd(ligand)(anion)2] complex
due to the strongly-coordinating nature of the OAc– anions is formed directly in all cases studied.
(perhaps in a bridging manner). When the anions are
It is thus concluded that it is important to realize that
weakly coordinating (OTs–) the P2O2 donor set is formed the formation of [Pd(ligand)(anion)2]-type complexes is not
immediately. That the ligand L14 does not form the bischel- always instantaneous or successful. Thus, when performing
ate complex (e.g., a P4 donor set like its propylene-bridged catalytic reactions with in situ formed complexes, one
analogue L4) is ascribed to its larger bite-angle (β ≈ 99° should make sure that the desired complex will actually
Eur. J. Inorg. Chem. 2010, 298–310
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
305

T. J. Mooibroek, E. Bouwman, M. Lutz, A. L. Spek, E. Drent
FULL PAPER
molecule were refined freely with isotropic displacement param-
eters. [Pd(L10)(OAc)2]: Hydrogen atoms of the water molecules
were kept fixed at the positions located in difference Fourier maps.
The methyl groups of the acetate ligands were refined with two
conformations, respectively. [Pd(L10)2](OTs)2: The crystal structure
contains solvent accessible voids (1046 Å3/unit cell) filled with dis-
ordered solvent molecules. Their contribution to the structure fac-
tors was secured by back-Fourier transformation using the
SQUEEZE routine of the program PLATON[56] resulting in 307 e–/
unit cell.
form. We hope to have provided a significant contribution
to the fundamental understanding of whether the desired
catalyst will indeed be formed.
Experimental Section
Materials: Solvents and chemicals were commercially available as
A.R. grade and used as received, unless stated otherwise. The li-
gand and complex syntheses were performed under argon and the
purifications were commonly performed in air, unless stated other-
wise. A schematic overview of the ligands used in this study is pre-
sented in Table 1. The ligands L1, L4, L14, and L17 are commer-
cially available and were used as received. The ligands L5, L15, and
L16 have been synthesized according to literature procedures.[38–41]
The other ligands were obtained as a gift from Shell International
Chemicals B.V., where they were prepared according to literature
procedures.[42–50] All ligand molecular data are summarized in
Table S1.
NMR Spectroscopic Complex Formation Studies
Preparation of the Samples, Using Pd(OAc)2: The ligand
(12.8 µmol) was weighed into an NMR tube and put under argon.
In another tube, Pd(OAc)2 (3.59 mg, 16 µmol) was dissolved in
1 mL of solvent under argon. Of this solution, (0.8 mL, 12.8 µmol
of Pd) was added to the ligand using a 1-mL syringe, which was
dry and flushed with argon. The thus obtained mixture (16 m)
was thoroughly mixed using a vortex mixer until a clear solution
was obtained. When no clear solution was obtained within ten min-
utes of mixing, the sample was considered to be insoluble and was
discarded.
Physical Methods
Common Analytical Techniques: 1H- and 31P{1H}-NMR spectra
were recorded using a DPX Bruker instrument operating at 300 or
400 MHz. Chemical shifts are reported in δ (parts per million); the
proton resonances are given relative to the solvent peak [CD3OD
= 3.33 ppm, (CH3)2SO = 2.50 ppm, (CH3)2CO = 2.06 ppm, CDCl3
Preparation of the Samples, Using Pd(OTs)2: The ligand
(12.8 µmol) was weighed into an NMR tube and put under argon.
In another tube, Pd(OAc)2 (3.59 mg, 16 µmol) and HOTs (5.51 mg,
32 µmol) were dissolved in 1 mL of (CD3)2CO in CD2Cl2 (17%
= 7.26 ppm, CD2Cl2 = 5.30 ppm] or tetramethylsilane (TMS, v/v), under argon. Of this solution, 0.8 mL (12.8 µmol of Pd) was
0 ppm). The phosphorus resonances are given relative to the exter- added to the ligand using a 1-mL syringe, which was dry and
nal standard H3PO4 (85%, 0 ppm). C, H, and N analyses were flushed with argon. The thus obtained mixture (16 m) was thor-
carried out using an automatic Perkin–Elmer 2400 Series II CHNS/ oughly mixed using a vortex mixer until a clear solution was ob-
O microanalyzer. ESI Mass Spectroscopy was carried out using a tained. When no clear solution was obtained within ten minutes of
Finnigan Aqua Mass Spectrometer equipped with an electrospray
ionization (ESI) source. Sample solutions (10 µL of a 1 mg/mL
solution) were introduced in the ESI source by using a Dionex ASI-
100 automated sampler injector and an eluent running at 0.2 mL/
min.
mixing, the sample was considered to be insoluble and was dis-
carded.
NMR Kinetic Measurements: The clear solutions were monitored
1
with H- and 31P{1H}-NMR spectroscopy, over a period of about
four to fourteen hours. All measurements of the same experiment
(e.g., a specific complex formation study) were recorded with an
identical number of free inductive decays (FIDs). For a typical pro-
X-ray Crystal Structure Determinations: X-ray intensities were mea-
sured with a Nonius KappaCCD diffractometer with rotating an-
ode (graphite monochromator, λ = 0.71073 Å) at a temperature of ton measurement, the number of FIDs was 16. For the phosphorus
150(2) K. Data were integrated with the HKL2000[51]
([Pd(L2)(OAc)2], [Pd(L10)(OAc)2], [Pd(L10)](OTs)2) or Eval-
CCD[52] ([Pd(L7)(OAc)2], [Pd(L13)(OAc)2]) software. The struc-
tures were solved with Direct Methods using the programs SIR-
97[53] ([Pd(L2)(OAc)2], [Pd(L10)](OTs)2) and SHELXS-97[54]
([Pd(L10)(OAc)2]) or with automated Patterson Methods using the
program DIRDIF-99[55] ([Pd(L7)(OAc)2], [Pd(L13)(OAc)2]). The
structures were refined with SHELXL-97.[54] Non-hydrogen atoms
were refined with anisotropic displacement parameters. Hydrogen
atoms were located in difference-Fourier maps ([Pd(L2)(OAc)2],
[Pd(L10)(OAc)2]) or introduced in calculated positions
([Pd(L7)(OAc)2], [Pd(L13)(OAc)2], [Pd(L10)2](OTs)2) and refined
with a riding model. Drawings, structure calculations and checking
for higher symmetry were performed with the PLATON soft-
ware.[56] Further experimental details are given in Table 4.
NMR spectra the number of FIDs was typically 40.
Data Analysis: For the data analysis of the complex formation
studies, the integral of an isolated aromatic resonance of the inter-
mediate species was taken relative to the total integral of all aro-
matic protons. The natural logarithm of this number was plotted
against time, which always resulted in a hyperbolically shaped
curve. Of the initial linear part, the best fit was calculated with the
least-squares method. These are the graphs that are given in this
paper. The slopes of these linear functions reflect the (presumed
first order) reaction constant (kЈ), not in absolute, but in relative
sense. This was done because the exact nature of the disappearing
species is (in most cases) unknown.
Low-Temperature NMR Spectroscopic Experiments: Some of the
1
obtained complexes were characterized by H and 31P{1H} NMR
spectroscopy, both at room temperature (20 °C) and at low tem-
perature (–60 °C). This was typically done by monitoring the 1H
and 31P NMR resonances of a 16 m solution during cooling at
20, 0, –20, –40, and –60 °C. Before a spectrum at a specific tem-
perature was recorded, it was ensured that the cooling apparatus
was stable with an error of about 1 °C. When this was achieved, a
waiting period of about ten minutes was applied to ensure that the
sample had acquired the temperature as indicated by the cooling
apparatus.
CCDC-748839 (for [Pd(L2)(OAc)2]), -748840 (for [Pd(L7)-
(OAc)2]), -748841 (for [Pd(L10)(OAc)2]), -748842 (for [Pd(L13)-
(OAc)2]), -748843 (for [Pd(L10)2](OTs)2) contain the supplementary
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.
[Pd(L2)(OAc)2]: The CHCl3 solvent molecule was refined with a
disorder model. [Pd(L7)(OAc)2]: Hydrogen atoms of the water
306
www.eurjic.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2010, 298–310

PdII Complexes of Bidentate Diphenylphosphane Ligands
General Synthetic Methods for the Synthesis of the Complexes
5.08, S 5.88; found C 54.24, H 5.00, S 5.91. ESI Mass Spectroscopy,
m/z found (calcd.): [M – OTs]+ = 674.70 (675.05).
Method A. For [Pd(L)(OAc)2]: A solution of Pd(OAc)2 (74 m) in
CH2Cl2 was prepared and filtered. A 25-mL round-bottomed flask
filled with argon was charged with 10 mL of this solution and a
magnetic stirring rod. To the stirred solution, 0.74 mmol of the
solid ligand was added and the reaction mixture was stirred over-
night (wrapped in aluminium foil), where after the solvent volume
was reduced to about 5 mL. The complex was precipitated with
Et2O/n-hexane, collected by filtration through a glass frit (P4),
washed with Et2O/n-hexane and dried in vacuo.
[Pd(L1)2](OTs)2 (B1T): This compound was prepared following
method D. The product was obtained as a yellow powder, with an
isolated yield of 92% (573 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with n-
1
hexane. H NMR (300 MHz, CHCl3): δ = 8.08 (d, 4 H, o-OTs-H),
7.46 (m, 20 H, m-Ph-H, m-OTs-H), 7.26 (m, 20 H, o-Ph-H, p-Ph-
H), 3.16 (m, 8 H, PCH2), 2.39 (s, 6 H, p-OTs-CH3) ppm. 31P NMR
(300 MHz, CHCl3): δ = 56.74 ppm. Elemental analyses for [Pd-
(L1)2](OTs)2. C66H62O6P4PdS2 (1245.64)·2CH2Cl2·C6H14: calcd. C
59.19, H 5.37, S 4.05; found C 59.26, H 5.25, S 3.94. ESI Mass
Spectroscopy, m/z found (calcd.): [M – OTs]+ = 1072.73 (1073.19).
Method B. For [Pd(L)(OTs)2]: A solution of Pd(OAc)2 (74 m) in
CH2Cl2 was prepared and filtered. A 25-mL round-bottomed flask
filled with argon was charged with 10 mL of this solution and a
magnetic stirring rod. To the stirred solution, 0.74 mmol of the
solid ligand was added and the reaction mixture was stirred over-
night (wrapped in aluminium foil). Then, para-toluenesulfonic acid
(1.5 mmol, 0.26 g) was added and the solvent volume was reduced
to about 5 mL. The complex was precipitated with Et2O/n-hexane,
collected by filtration through a glass frit (P4), washed with Et2O/
n-hexane and dried in vacuo.
[Pd(L2)(OAc)2] (M2A): This compound was prepared following
method A. The product was obtained as a yellow powder, with an
isolated yield of 81% (445 mg). Single crystals suitable for X-ray
crystallography were obtained by layering a solution of the complex
in dichloromethane with n-hexane. 1H NMR (300 MHz, CDCl3): δ
= 8.04 (q, 4 H, o-Ph-H), 7.50 (t, 4 H, p-Ph-H), 7.04 (t, 4 H, OC=C-
H), 6.92 (q, 4 H, m-Ph-H), 3.72 (s, 12 H, OCH3), 2.63 (d, 4 H,
PCH2), 1.36 [s, 6 H, OC(O)CH3] ppm. 31P NMR (300 MHz,
CDCl3): δ = 60.91 ppm. Elemental analyses for [Pd(L2)(OAc)2],
C34H38O8P2Pd (743.03)·0.3H2O: calcd. C 54.52, H 5.20; found C
54.99, H 5.65. ESI Mass Spectroscopy, m/z found (calcd.): [M –
OAc]+ = 682.75 (683.98).
Method C. For [Pd(L)2](OAc)2: A 25-mL round-bottomed flask
filled with argon was charged with 15 mL MeOH, 1 mmol of the
ligand, and a stirring rod. The resulting suspension was stirred, and
2 mL of a filtered Pd(OAc)2 solution (0.25  in CH2Cl2) was added.
After overnight stirring (wrapped in aluminium foil), the solvent
volume was reduced to about 5 mL. The complex was precipitated
with Et2O/n-hexane, collected by filtration through a glass frit (P4),
washed with Et2O/n-hexane and dried in vacuo.
[Pd(L2)(OTs)2] (M2T): This compound was prepared following
method B. The product was obtained as a yellow powder, with an
isolated yield of 68% (487 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with di-
1
ethyl ether. H NMR [300 MHz, OC(CH3)2]: δ = 7.65 (m, 4 H, p-
Method D. For [Pd(L)2](OTs)2: A 25-mL round-bottomed flask
filled with argon was charged with 15 mL MeOH, 1 mmol of the
ligand, and a stirring rod. In another round-bottomed flask,
2 mmol (0.35 g) of para-toluenesulfonic acid was added to 4 mL of
a 0.25  solution of Pd(OAc)2 in CH2Cl2. From this solution, 2 mL
were added to the ligand/MeOH suspension. After overnight stir-
ring (wrapped in aluminium foil), the solvent volume was reduced
to about 5 mL. The complex was precipitated with Et2O/n-hexane,
collected by filtration through a glass frit (P4), washed with Et2O/
n-hexane and dried in vacuo.
Ph-H, o-Ph-H), 7.50 (d, 4 H, o-OTs-H), 7.24 (t, 4 H, OC=C-H),
7.09 (m, 8 H, m-Ph-H, m-OTs-H), 3.80 (s, 12 H, OCH3), 3.05 (m,
4 H, PCH2), 2.29 (s, 6 H, p-OTs-CH3) ppm. 31P NMR [300 MHz,
OC(CH3)2]: δ = 57.50 ppm. Elemental analyses for [Pd(L2)(OTs)2],
C44H46O10P2PdS2 (967.33)·1CH2Cl2·0.25O(C2H3)2: calcd. C 51.60,
H 4.75, S 2.97; found C 51.67, H 4.64, S 2.82. ESI Mass Spec-
troscopy, m/z found (calcd.): [M – OTs]+ = 794.77 (796.13).
[Pd(L2)2](OAc)2 (B2A): This compound was prepared following
method C. The product was obtained as a yellow powder, with an
isolated yield of 73% (460 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with di-
Complexes
1
[Pd(L1)(OAc)2] (M1A): This compound was prepared following
method A. The product was obtained as a yellow powder, with an
isolated yield of 97% (447 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with di-
ethyl ether. 1H NMR (300 MHz, CH3OH): δ = 7.80 (q, 8 H, m-Ph-
H), 7.52 (m, 4 H, p-Ph-H), 7.45 (t, 8 H, o-Ph-H), 2.50 (m, 4 H,
PCH2), 1.49 (s, 6 H, OC(O)CH3) ppm. 31P NMR (300 MHz,
CH3OH): δ = 63.66 ppm. [Pd(L1)(OAc)2]: C30H30O4P2Pd (622.92)
·0.75CH2Cl2: calcd. C 53.79, H 4.62; found C 53.58, H 4.65. ESI
Mass Spectroscopy, m/z found (calcd.): [M – OAc]+ = 562.66
(563.05).
ethyl ether. H NMR (300 MHz, CDCl3): δ = 8.14 [br., 4 H, o-Ph-
H(ax)], 7.80 [t, 4 H, p-Ph-H(ax)], 7.54 [m, 4 H, m-Ph-H(ax)], 7.35
[m, 4 H, m-Ph-H(eq)], 7.11 [d, 4 H, OC=C-H(ax)], 6.88 [d, 4 H,
OC=C-H(eq)], 6.46 [t, 4 H, p-Ph-H(eq)], 5.88 [br., 4 H, o-Ph-
H(eq)], 3.68 [s, 12 H, OCH3(ax)], 3.59 [s, 12 H, OCH3(eq)], 3.20
(m, 8 H, PCH2), 2.02 [s, 6 H, OC(O)CH3] ppm. 31P NMR
(300 MHz, CDCl3): δ = 55.83 ppm. Elemental analyses for [Pd(L2)2]-
(OAc)2, C64H70O12P4Pd (1261.55)·1O(C2H3)2·3H2O: calcd.
C
52.63, H 5.70; found C 52.35, H 5.93. ESI Mass Spectroscopy, m/z
found (calcd.): [M – 2OAc]2+ = 571.72 (571.73).
[Pd(L2)2](OTs)2 (B2T): This compound was prepared following
method D. The product was obtained as a yellow powder, with an
isolated yield of 30% (223 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with di-
[Pd(L1)(OTs)2] (M1T): This compound was prepared following
method B. The product was obtained as a yellow powder, with an
isolated yield of 89% (558 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with n-
1
ethyl ether. H NMR (300 MHz, CDCl3): δ = 8.08 [br., 4 H, o-Ph-
1
hexane. H NMR [300 MHz, OC(CH3)2]: δ = 7.95 (q, 8 H, m-Ph-
H(ax)], 7.89 (d, 4 H, o-OTs-H), 7.81 [t, 4 H, p-Ph-H(ax)], 7.50 [t,
4 H, m-Ph-H(ax)], 7.26 [t, 4 H, m-Ph-H(eq)], 7.12 (d, 4 H, m-OTs-
H), 6.97 [d, 4 H, OC=C-H(ax)], 6.82 [d, 4 H, OC=C-H(eq)], 6.56
[t, 4 H, p-Ph-H(eq)], 5.84 [br., 4 H, o-Ph-H(eq)], 3.67 [s, 12 H,
OCH3(ax)], 3.52 [s, 12 H, OCH3(eq)], 3.03 (m, 8 H, PCH2), 2.33
(s, 6 H, p-OTs-CH3) ppm. 31P NMR (300 MHz, CDCl3): δ =
H), 7.76 (m, 4 H, p-Ph-H), 7.63 (m, 8 H, o-Ph-H), 7.51 (d, 4 H, o-
OTs-H), 7.11 (d, 4 H, m-OTs-H), 3.08 (m, 4 H, PCH2), 2.32 (s, 6
H, p-OTs-CH3) ppm. 31P NMR [300 MHz, OC(CH3)2]: δ =
74.26 ppm.
Elemental
analyses
for
[Pd(L1)(OTs)2].
C40H38O6P2PdS2 (847.22)·0.5CH2Cl2·0.25C6H14: calcd. C 54.24, H
Eur. J. Inorg. Chem. 2010, 298–310
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
307

T. J. Mooibroek, E. Bouwman, M. Lutz, A. L. Spek, E. Drent
FULL PAPER
55.95 ppm.
Elemental
analyses
for
[Pd(L2)2](OTs)2,
[Pd(L7)(OAc)2] (M7A): This compound was prepared following
method A. The product was obtained as a yellow powder, with an
isolated yield of 87% (487 mg). Single crystals suitable for X-ray
crystallography were obtained by layering of n-hexane with a solu-
tion of the complex in dichloromethane. 1H NMR (300 MHz,
CDCl3): δ = 8.25 (br., 4 H, o-Ph-H), 7.50 (t, 4 H, p-Ph-H), 7.08
(br., 4 H, m-Ph-H), 6.94 (d, 4 H, OC=C-H), 3.76 (s, 12 H, OCH3),
2.44 (m, 4 H, PCH2), 1.95 (m, 2 H, PCH2CH2), 1.26 [s, 6 H, OC(-
O)CH3] ppm. 31P NMR (300 MHz, CDCl3): δ = 14.50 ppm. Ele-
mental analyses for [Pd(L7)(OAc)2], C35H40O8P2Pd (757.05)·
CH2Cl2: calcd. C 54.35, H 6.08; found C 54.18, H 6.21. ESI Mass
Spectroscopy, m/z found (calcd.): [M – OAc]+ = 698.62 (698.01).
C74H78O14P4PdS2 (1485.85)·2CH2Cl2·2O(C2H3)2: calcd. C 55.93, H
5.70, S 3.63; found C 56.04, H 5.88, S 3.80. ESI Mass Spectroscopy,
m/z found (calcd.): [M – OTs]+ = 1072.73 (1073.19).
[Pd(L4)(OAc)2] (M4A): This compound was prepared following
method A. The product was obtained as a yellow powder, with an
isolated yield of 93% (438 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with di-
1
ethyl ether. H NMR (300 MHz, CHCl3): δ = 7.72 (m, 8 H, m-Ph-
H), 7.34 (m, 12 H, o-Ph-H, p-Ph-H), 2.51 (m, 4 H, PCH2), 2.15
(m, 2 H, PCH2CH2), 1.34 [s, 6 H, OC(O)CH3] ppm. 31P NMR
(300 MHz, CHCl3):
δ = 9.74 ppm. Elemental analyses for
[Pd(L4)(OAc)2], C31H32O4P2Pd (636.95)·0.5CH2Cl2·0.5O(C2H3)2:
calcd. C 56.16, H 5.35; found C 56.64, H 5.33. ESI Mass Spec-
troscopy, m/z found (calcd.): [M – OAc]+ = 576.65 (577.91).
[Pd(L7)2](OAc)2 (B7A): This compound was prepared following
method C. The product was obtained as a yellow powder, with an
isolated yield of 94% (606 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with di-
ethyl ether. 1H NMR (300 MHz, CH3OH): δ = 8.59 [br., 4 H, o-
Ph-H(ax)], 7.74 [t, 4 H, m-Ph-H(ax)], 7.46 [t, 4 H, p-Ph-H(ax)],
7.30 [t, 4 H, p-Ph-H(eq)], 7.05 [m, 8 H, OC=C-H(ax, eq.)], 6.61 [t,
4 H, m-Ph-H(eq)], 5.91 [br., 4 H, o-Ph-H(eq)], 4.23 [s, 12 H,
OCH3(ax)], 3.42 [s, 12 H, OCH3(eq)], 2.90 [m, 4 H, PCH2(ax)], 2.38
[m, 4 H, PCH2(eq)], 1.95 (m, 2 H, PCH2CH2), 1.87 [s, 6 H, OC(O)
CH3] ppm. 31P NMR (300 MHz, CH3OH): δ = 5.56 ppm. Elemen-
tal analyses for [Pd(L7)2](OAc)2, C66H74O12P4Pd (1289.60)·
CH2Cl2: calcd. C 55.96, H 6.58; found C 55.91, H 6.58. ESI Mass
Spectroscopy, m/z found (calcd.): [M – 2 OAc]2+ = 584.83 (585.15).
[Pd(L4)(OTs)2] (M4T): This compound was prepared following
method B. The product was obtained as a yellow powder, with an
isolated yield of 78% (497 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with di-
1
ethyl ether. H NMR (300 MHz, CHCl3): δ = 7.67 (q, 8 H, o-Ph-
H), 7.41 (m, 8 H, p-Ph-H, o-OTs-H), 7.26 (t, 8 H, m-Ph-H), 6.86
(d, 4 H, m-OTs-H), 2.83 (m, 4 H, PCH2), 2.25 (m, 2 H, PCH2CH2),
2.31 (s, 6 H, p-OTs-CH3) ppm. 31P NMR (300 MHz, CHCl3): δ =
15.88 ppm.
Elemental
analyses
for
[Pd(L4)(OTs)2],
C41H40O6P2PdS2 (861.25)·1.3H2O: calcd. C 55.63, H 4.86, S 5.15;
found C 55.73, H 4.79, S 5.51. ESI Mass Spectroscopy, m/z found
(calcd.): [M – OTs]+ = 688.71 (689.07).
[Pd(L7)2](OTs)2 (B7T): This compound was prepared following
method D. The product was obtained as a yellow powder, with an
isolated yield of 72% (545 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with di-
[Pd(L5)(OAc)2] (M5A): This compound was prepared following
method A. The product was obtained as a yellow powder, with an
isolated yield of 96% (472 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with di-
1
ethyl ether. H NMR (300 MHz, CHCl3): δ = 8.51 [br., 4 H, o-Ph-
1
H(ax)], 7.96 (d, 4 H, o-OTs-H), 7.73 [t, 4 H, m-Ph-H(ax)], 7.64 [t,
4 H, p-Ph-H(ax)], 7.20 [m, 8 H, p-Ph-H(eq), m-OTs-H], 6.99 [d, 4
H, OC=C-H(ax)], 6.83 [d, 4 H, OC=C-H(eq)], 6.47 [t, 4 H, m-Ph-
H(eq)], 5.82 [br., 4 H, o-Ph-H(eq)], 4.33 [s, 12 H, OCH3(ax)], 3.38
[s, 12 H, OCH3(eq)], 2.85 [m, 4 H, PCH2(ax)], 2.36 (s, 6 H, p-OTs-
CH3), 2.25 [m, 4 H, PCH2(eq)], 1.52 (br., 4 H, PCH2CH2) ppm.
31P NMR (300 MHz, CHCl3): δ = 4.81 ppm. Elemental analyses
for [Pd(L7)2](OTs)2, C76H82O14P4PdS2 (1513.90)·0.25CH2Cl2·
0.25O(C2H3)2: calcd. C 59.72, H 5.52, S 3.96; found C 59.48, H
5.87, S 3.96. ESI Mass Spectroscopy, m/z found (calcd.): [M –
OTs]+ = 1340.53 (1341.30).
ethyl ether. H NMR (300 MHz, CHCl3): δ = 7.90 (m, 8 H, o-Ph-
H), 7.44 (m, 12 H, m-Ph-H, p-Ph-H), 2.29 (d, 4 H, PCH2), 0.91 (s,
6 H, CCH3), 1.44 [s, 6 H, OC(O)CH3] ppm. 31P NMR (300 MHz,
CHCl3): δ = 16.35 ppm. Elemental analyses for [Pd(L5)(OAc)2],
C33H36O4P2Pd (665.00)·0.25CH2Cl2·0.5O(C2H3)2: calcd. C 58.62,
H 5.65; found C 58.66, H 5.57. ESI Mass Spectroscopy, m/z found
(calcd.): [M – OAc]+ = 604.77 (605.10).
[Pd(L5)(OTs)2] (M5T): This compound was prepared following
method B. The product was obtained as a yellow powder, with an
isolated yield of 83% (546 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with di-
ethyl ether. 1H NMR (300 MHz, CH3OH): δ = 7.88 (d, 4 H, o-
OTs-H), 7.58 (br., 8 H, o-Ph-H), 7.29 (m, 16 H, m-Ph-H, p-Ph-H,
m-OTs-H), 2.59 (br., 4 H, PCH2), 2.38 (s, 6 H, p-OTs-CH3), 0.26
(s, 6 H, CCH3) ppm. 31P NMR (300 MHz, CH3OH): δ = 6.72 ppm.
Elemental analyses for [Pd(L5)(OTs)2], C43H44O6P2PdS2 (889.30)·
CH2Cl2·1.25O(C2H5)2: calcd. C 55.29, H 5.30, S 4.52; found C
55.37, H 5.19, S 4.69. ESI Mass Spectroscopy, m/z found (calcd.):
[M – OTs]+ = 688.71 (689.07).
[Pd(L10)(OAc)2] (M10A): This compound was prepared following
method A. The product was obtained as a yellow powder, with an
isolated yield of 96% (558 mg). Single crystals suitable for X-ray
crystallography were obtained by layering of n-hexane with a solu-
tion of the complex in dichloromethane. 1H NMR (300 MHz,
CDCl3): δ = 8.15 (br., 4 H, o-Ph-H), 7.51 (t, 4 H, m-Ph-H), 7.07
(m, 4 H, p-Ph-H), 6.92 (d, 4 H, OC=C-H), 3.86 (s, 12 H, OCH3),
2.58 (d, 4 H, PCH2), 1.20 [s, 6 H, OC(O)CH3], 0.33 (s, 6 H, CCH3)
ppm. 31P NMR (300 MHz, CDCl3): δ = 20.84 ppm. Elemental
analyses for [Pd(L10)(OAc)2], C37H44O8P2Pd (785.11)·CH2Cl2·
0.7C6H12: calcd. C 54.51, H 6.01; found C 54.39, H 5.96. ESI Mass
Spectroscopy, m/z found (calcd.): [M –OAc]+ = 724.77 (726.06).
[Pd(L5)2](OTs)2 (B5T): This compound was prepared following
method D. The product was obtained as a yellow powder, with an
isolated yield of 92% (612 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with di-
ethyl ether. 1H NMR (300 MHz, CH3OH): δ = 8.00 (d, 4 H, o-
[Pd(L10)2](OAc)2 (B10A): This compound was prepared following
OTs-H), 7.60 (br., 16 H, o-Ph-H), 7.26 (m, 28 H, m-Ph-H, p-Ph-H, method C. The product was obtained as a yellow powder, with an
m-OTs-H), 2.62 (br., 8 H, PCH2), 2.38 (s, 6 H, p-OTs-CH3), 0.26 (s, isolated yield of 97% (653 mg). The compound was recrystallized
12 H, CCH3) ppm. 31P NMR (300 MHz, CH3OH): δ = 5.63 ppm. by layering a solution of the complex in dichloromethane with di-
Elemental analyses for [Pd(L5)2](OTs)2, C72H74O6P4PdS2 (1329.80)·
ethyl ether. 1H NMR (300 MHz, CH3OH): δ = 8.36 [br., 4 H, o-
1.25CH2Cl2·O(C2H3)2: calcd. C 63.83, H 6.00, S 4.33; found C Ph-H(ax)], 7.64 [t, 4 H, m-Ph-H(ax)], 7.30 [m, 8 H, p-Ph-H(ax), p-
63.73, H 6.24, S 4.62. ESI Mass Spectroscopy, m/z found (calcd.):
Ph-H(eq)], 7.11 [d, 4 H, OC=C-H(ax)], 6.92 [d, 4 H, OC=C-H(eq)],
6.70 [t, 4 H, m-Ph-H(eq)], 6.48 [br., 4 H, o-Ph-H(eq)], 4.26 [s, 12
[M – OTs]+ = 1156.91 (1157.28).
308
www.eurjic.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2010, 298–310

PdII Complexes of Bidentate Diphenylphosphane Ligands
H, OCH3(ax)], 3.41 [s, 12 H, OCH3(eq)], 2.78 [d, 4 H, PCH2(ax)],
2.44 [d, 4 H, PCH2(eq)], 1.88 [s, 6 H, OC(O)CH3], 0.22 (s, 12 H,
CCH3) ppm. 31P NMR (300 MHz, CH3OH): δ = 10.88 ppm. Ele-
1.42 (br.,
OCCH2CH2CH2) ppm. 31P NMR (300 MHz, CHCl3):
8.03 ppm. Elemental analyses for [Pd(L13)2](OTs)2,
8 H, OCCH2), 1.23 (br., 12 H, OCCH2CH2,
δ
=
mental analyses for [Pd(L10)2](OAc)2, C70H82O12P4Pd (1345.71)· C92H106O18P4PdS2 (1794.26)·0.33CH2Cl2: calcd. C 60.84, H 5.90,
2.5CH2Cl2·2.5O(C2H3)2: calcd. C 57.28, H 6.44; found C 56.97, H
S 3.50; found C 60.84, H 5.90, S 3.02. ESI Mass Spectroscopy, m/z
6.90. ESI Mass Spectroscopy, m/z found (calcd.): [M – 2OAc]2+
=
found (calcd.): [M – 2 OTs]2+ = 726.50 (725.94).
613.43 (613.18).
[Pd(L14)(OAc)2] (M14A): This compound was prepared following
method A. The product was obtained as a yellow powder, with an
isolated yield of 96% (463 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with di-
[Pd(L10)2](OTs)2 (B10T): This compound was prepared following
method D. The product was obtained as a yellow powder, with an
isolated yield of 89% (699 mg). Single crystals suitable for X-ray
crystallography were obtained by layering of hexane with a solution
1
ethyl ether. H NMR (300 MHz, CH3OH): δ = 7.63 (q, 8 H, o-Ph-
1
H), 7.47 (t, 4 H, p-Ph-H), 7.34 (t, 8 H, m-Ph-H), 2.44 (br., 4 H,
PCH2), 1.93 (m, 4 H, PCH2CH2), 1.32 [s, 6 H, OC(O)CH3] ppm.
31P NMR (300 MHz, CH3OH): δ = 28.56 ppm. Elemental analyses
for [Pd(L14)(OAc)2], C32H34O4P2Pd (650.98)·1.5CH2Cl2: calcd. C
51.69, H 4.79; found C 51.88, H 4.93. ESI Mass Spectroscopy, m/z
found (calcd.): [M – OAc]+ = 590.73 (591.08).
of the complex in acetone. H NMR (300 MHz, CDCl3): δ = 8.29
[br., 4 H, o-Ph-H(ax)], 7.95 (d, 4 H, o-OTs-H), 7.56 [m, 8 H, p-Ph-
H(ax), m-Ph-H(ax)], 7.16 [m, 8 H, p-Ph-H(eq), m-OTs-H], 7.07 [d,
4 H, OC=C-H(ax)], 6.68 [d, 4 H, OC=C-H(eq)], 6.53 [t, 4 H, m-
Ph-H(eq)], 6.34 [br., 4 H, o-Ph-H(eq)], 4.38 [s, 12 H, OCH3(ax)],
3.38 [s, 12 H, OCH3(eq)], 2.70 [d, 4 H, PCH2(ax)], 2.36 (s, 6 H, p-
OTs-CH3), 2.30 [d, 4 H, PCH2(eq)], 0.12 (s, 12 H, CCH3) ppm. 31
NMR (300 MHz, CDCl3): δ = 10.10 ppm. Elemental analyses for
[Pd(L10)2](OTs)2, C80H90O14P4PdS2 (1570.01)·0.25CH2Cl2·
P
[Pd(L14)(OTs)2] (M14T): This compound was prepared following
method B. The product was obtained as a yellow powder, with an
isolated yield of 92% (596 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with di-
0.5C6H14: calcd. C 58.87, H 5.79, S 3.92; found C 58.40, H 5.99, S
3.51. ESI Mass Spectroscopy, m/z found (calcd.): [M – OTs]+
=
1
ethyl ether. H NMR (300 MHz, CHCl3): δ = 7.70 (t, 8 H, p-Ph-
1396.47 (1396.37).
H), 7.54 (t, 8 H, m-Ph-H), 7.40 (m, 8 H, o-Ph-H, o-OTs-H), 6.93
(d, 4 H, m-OTs-H), 2.58 (br., 4 H, PCH2), 2.31 (s, 6 H, p-OTs-CH3),
2.15 (m, 4 H, PCH2CH2) ppm. 31P NMR (300 MHz, CHCl3): δ
[Pd(L13)(OAc)2] (M13A): This compound was prepared following
method A. The product was obtained as a yellow powder, with an
isolated yield of 94% (624 mg). Single crystals suitable for X-ray
crystallography were obtained by layering of n-hexane with a solu-
=
32.80 ppm. Elemental analyses for [Pd(L14)(OTs)2],
C42H42O6P2PdS2 (875.28)·1.25CH2Cl2·1.25O(C2H3)2: calcd.
C
1
54.08, H 5.13, S 5.02; found C 54.22, H 5.00, S 5.13. ESI Mass
tion of the complex in acetone. H NMR (300 MHz, CDCl3): δ =
Spectroscopy, m/z found (calcd.): [M – OTs]+ = 702.62 (703.08).
8.50 (br., 4 H, o-Ph-H), 7.52 (br., 4 H, m-Ph-H), 7.08 (br., 4 H, p-
Ph-H), 6.94 (d, 4 H, OC=C-H), 3.88 (s, 12 H, OCH3), 3.09 (s, 4 H,
CCH2O), 2.68 (s, 4 H, PCH2), 1.57 (m, 4 H, OCCH2), 1.37 (m, 6
H, OCCH2CH2, OCCH2CH2CH2), 1.21 [s, 6 H, OC(O)CH3] ppm.
31P NMR (300 MHz, CDCl3): δ = 18.05 ppm. Elemental analyses
for [Pd(L13)(OAc)2], C43H52O10P2Pd (897.23): calcd. C 57.56, H
5.84; found C 57.00, H 6.16. ESI Mass Spectroscopy, m/z found
(calcd.): [M – OAc]+ = 836.82 (838.19).
Supporting Information (see also the footnote on the first page of
this article): 1H and 31P NMR data, ESI-MS and elemental analysis
for the ligands and palladium complexes (Table S1); lists of hydro-
gen-bond interactions in M7A and M10A (Tables S2 and S3); per-
spective views of M2A, M7A and M13A (Figures S1–S5).
Acknowledgments
[Pd(L13)2](OAc)2 (B13A): This compound was prepared following
method C. The product was obtained as a yellow powder, with an
isolated yield of 70% (550 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with n-
hexane. 1H NMR (300 MHz, CH3OH): δ = 8.35 [br., 4 H, o-Ph-
H(ax)], 7.34 [t, 4 H, p-Ph-H(ax)], 7.29 [t, 4 H, p-Ph-H(eq)], 7.14 [d,
4 H, OC=C-H(ax)], 6.97 [d, 4 H, OC=C-H(eq)], 6.78 [t, 4 H, m-
Ph-H(ax)], 6.72 [t, 4 H, m-Ph-H(eq)], 6.48 [br., 4 H, o-Ph-H(eq)],
4.30 [s, 12 H, OCH3(ax)], 3.42 [s, 12 H, OCH3(eq)], 2.88 [d, 4 H,
PCH2(ax)], 2.56 [m, 12 H, PCH2(eq), CCH2O], 1.88 [s, 6 H, OC-
(O)CH3], 1.37 (m, 8 H, OCCH2), 1.23 (m, 12 H, OCCH2CH2,
OCCH2CH2CH2) ppm. 31P NMR (300 MHz, CH3OH): δ =
This research has been financially supported by the Council for
Chemical Sciences of the Netherlands Organisation for Scientific
Research (CW-NWO). This work has been performed under the
auspices of the joint NIOK Research Graduate School of Leiden
University and six other Dutch Universities. Mr. Fons Lefeber, Mr.
Kees Erkelens, and Mr. Johan Hollander (Leiden University) are
kindly acknowledged for their assistance with the NMR spectro-
scopic measurements. Dr. W. P. Mul (Shell Global Solutions B. V.)
is acknowledged for participating in some early discussions. S. von
Chrzanowski is acknowledged for performing the X-ray diffraction
experiment for [Pd(L13)(OAc)2].
8.82 ppm.
Elemental
analyses
for
[Pd(L13)2](OAc)2,
C82H98O16P4Pd (1569.96)·0.5CH2Cl2·0.5C6H14: calcd. C 62.03, H
6.45; found C 62.00, H 6.46. ESI Mass Spectroscopy, m/z found
(calcd.): [M – 2 OAc]2+ = 725.15 (725.23).
[1] E. Drent, P. H. M. Budzelaar, Chem. Rev. 1996, 96, 663–681.
[2] C. Bianchini, A. Meli, Coord. Chem. Rev. 2002, 225, 35–66.
[3] A. Marson, A. B. van Oort, W. P. Mul, Eur. J. Inorg. Chem.
2002, 3028–3031.
[4] F. Paul, Coord. Chem. Rev. 2000, 203, 269–323.
[5] E. Drent, P. W. N. M. van Leeuwen, European patent number
0.086.281.A1, 1982.
[6] E. Drent, European patent number 0.231.045.A2, 1987.
[7] F. Ragaini, C. Cognolato, M. Gasperini, S. Cenini, Angew.
Chem. Int. Ed. 2003, 42, 2886–2889.
[8] E. Drent, Pure Appl. Chem. 1990, 62, 661–669.
[9] P. Wehman, L. Borst, P. C. J. Kamer, P. W. N. M. van Leeuwen,
J. Mol. Catal. A 1996, 112, 23–36.
[Pd(L13)2](OTs)2 (B13T): This compound was prepared following
method D. The product was obtained as a yellow powder, with an
isolated yield of 63% (565 mg). The compound was recrystallized
by layering a solution of the complex in dichloromethane with n-
hexane. 1H NMR (300 MHz, CHCl3): δ = 8.28 [br., 4 H, o-Ph-
H(ax)], 8.00 (d, 4 H, o-OTs-H), 7.60 [m, 8 H, p-Ph-H(ax), m-Ph-
H(ax)], 7.17 [m, 20 H, OC=C-H(ax), p-Ph-H(eq), m-OTs-H], 6.74
[d, 4 H, OC=C-H(eq)], 6.54 [t, 4 H, m-Ph-H(eq)], 6.34 [br., 4 H, o-
Ph-H(eq)], 4.44 [s, 12 H, OCH3(ax)], 3.40 [s, 12 H, OCH3(eq)], 2.73
[d, 4 H, PCH2(ax)], 2.44 [m, 18 H, PCH2(eq), CCH2O, p-OTs-CH3], [10] E. Drent, European patent number 224292, 1987.
Eur. J. Inorg. Chem. 2010, 298–310
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
309

T. J. Mooibroek, E. Bouwman, M. Lutz, A. L. Spek, E. Drent
FULL PAPER
[11] A. Bontempi, E. Alessio, G. Chanos, G. Mestroni, J. Mol. Ca-
tal. 1987, 42, 67–80.
[12] S. Cenini, F. Ragaini, M. Pizzotti, F. Porta, G. Mestroni, E.
Alessio, J. Mol. Catal. 1991, 64, 179–190.
[13] R. Santi, A. M. Romano, F. Panella, G. Mestroni, A. Sessanti,
A. S. o Santi, J. Mol. Catal. A 1999, 144, 41–45.
[14] P. Leconte, F. Metz, A. Mortreux, J. A. Osborn, F. Paul, F.
Petit, A. Pillot, J. Chem. Soc., Chem. Commun. 1990, 1616–
1617.
[15] P. Wehman, V. E. Kaasjager, W. G. J. de Lange, F. Hartl, P. C. J.
Kamer, P. W. N. M. van Leeuwen, J. Fraanje, K. Goubitz, Or-
ganometallics 1995, 14, 3751–3761.
[33]
[34]
[35]
M. E. Jung, J. Am. Chem. Soc. 1991, 113, 224–232.
P. v. R. Schleyer, J. Am. Chem. Soc. 1961, 83, 1368–1373.
T. Hayashi, M. Konishi, Y. Kobori, M. Kumada, T. Higuchi,
K. Hirotsu, J. Am. Chem. Soc. 1984, 106, 158–163.
R. J. van Haaren, K. Goubitz, J. Fraanje, G. P. F. van Strijk-
donk, H. Oevering, B. Coussens, J. N. H. Reek, P. C. J. Kamer,
P. W. N. M. van Leeuwen, Inorg. Chem. 2001, 40, 3363–3372.
A. G. Avent, R. B. Bedford, P. A. Chaloner, S. Z. Dewa, P. B.
Hitckcock, J. Chem. Soc., Dalton Trans. 1996, 4633–4638.
L. Brandsma, H. D. Verkruijsse, Synth. Commun. 1990, 20,
2273–2274.
P. H. M. Budzelaar, J. A. van Doorn, N. Meijboom, Recl. Trav.
Chim. Pays-Bas-J. Roy. Neth. Chem. Soc. 1991, 110, 420–432.
J. A. van Doorn, PhD Thesis, University of Amsterdam 1991.
W. Hewertson, H. R. Watson, J. Chem. Soc. 1962, 1490–1494.
F. Bickelhaupt, United States Patent Number 4874897, 1989.
W. Eilenberg, European Patent Number 364046, 1991.
J. A. van Doorn, United States Patent Number 4994592, 1991.
R. van Ginkel, United States Patent Number 6548708, 2003.
E. Drent, United States Patent Number 5091587, 1992.
C. F. Hobbs, United States Patent Number 4120901, 1987.
P. W. Clark, B. J. Mulraney, J. Organomet. Chem. 1981, 217,
51–59.
J. M. Brown, B. A. Murrer, Tetrahedron Lett. 1980, 21, 581–
584.
R. L. Wife, A. B. van Oort, J. A. van Doorn, P. W. N. M.
van Leeuwen, Synthesis 1983, 71–73.
Z. Otwinowski, W. Minor, Methods in Enzymology, vol. 276
(Eds.: C. W. Carter, R. M. Sweet), Acedemic Press, 1997, pp.
307–326.
A. J. M. Duisenberg, L. M. J. Kroon-Batenburg, A. M. M.
Schreurs, J. Appl. Chem. 2003, 36, 220–229.
A. Altomare, M. C. Burla, M. Camalli, G. L. Cascarano, C.
Giacovazzo, A. Guagliardi, A. G. G. Moliterni, G. Polidori, R.
Spagna, J. Appl. Crystallogr. 1999, 32, 115–119.
G. M. Sheldrick, Acta Crystallogr., Sect. A 2008, 64, 112.
P. T. Beurskens, G. Admiral, G. Beurskens, W. P. Bosman, S.
Garcia-Granda, R. O. Gould, J. M. M. Smith, C. Smykalla,
The DIRDIF97 program system: Technical report of the Crystal-
lography Laboratory; University of Nijmegen, The Netherlands
1997.
[36]
[37]
[38]
[39]
[16] P. Wehman, G. C. Dol, E. R. Moorman, P. C. J. Kamer,
P. W. N. M. van Leeuwen, J. Fraanje, K. Goubitz, Organome-
tallics 1994, 13, 4856–4869.
[40]
[41]
[42]
[43]
[44]
[45]
[46]
[47]
[48]
[17] P. Wehman, Ph. D. Thesis, University of Amsterdam (UVA)
1995.
[18] F. Ragaini, M. Gasperini, S. Cenini, Adv. Synth. Catal. 2004,
346, 63–71.
[19] F. Ragaini, Dalton Trans. 2009, 6251–6266.
[20] J. H. Grate, D. R. Hamm, D. H. Valentine, United States
patent number 4.603.216, 1986.
[21] P. Wehman, R. E. Rulke, V. E. Kaasjager, P. C. J. Kamer, H.
Kooijman, A. L. Spek, C. J. Elsevier, K. Vrieze, P. W. N. M.
van Leeuwen, J. Chem. Soc., Chem. Commun. 1995, 331–332.
[22] D. Cremer, J. A. Pople, J. Am. Chem. Soc. 1975, 97, 1354–1358.
[23] C. Bianchini, A. Meli, W. Oberhauser, Dalton Trans. 2003,
2627–2635.
[24] F. A. Cotton, S. Han, Rev. Chim. Miner. 1983, 20, 496–503.
[25] A. G. Orpen, L. Brammer, F. H. Allen, O. Kennard, D. G. Wat-
son, R. Taylor, J. Chem. Soc., Dalton Trans. 1989, S1.
[26] I. M. Angulo, E. Bouwman, M. Lutz, W. P. Mul, A. L. Spek,
Inorg. Chem. 2001, 40, 2073–2082.
[27] C. Bianchini, A. Meli, W. Oberhauser, A. M. Segarra, C. Cla-
ver, E. J. G. Suarez, J. Mol. Catal. A 2007, 265, 292–305.
[28] M. Brookhart, M. L. H. Green, G. Parkin, Proc. Natl. Acad.
Sci. USA 2007, 104, 6908–6914.
[29] J. F. Malone, C. M. Murray, M. H. Charlton, R. Docherty,
A. J. Lavery, J. Chem. Soc. Faraday Trans. 1997, 93, 3429–3436.
[30] C. Bianchini, H. M. Lee, A. Meli, W. Oberhauser, M. Peruz-
zini, F. Vizza, Organometallics 2002, 21, 16–33.
[49]
[50]
[51]
[52]
[53]
[54]
[55]
[31] C. Bianchini, P. Bruggeller, C. Claver, G. Czermak, A. Dum-
fort, A. Meli, W. Oberhauser, E. J. G. Suarez, Dalton Trans.
2006, 2964–2973.
[32] I. M. Angulo, E. Bouwman, R. van Gorkum, S. M. Lok, M.
Lutz, A. L. Spek, J. Mol. Catal. A 2003, 202, 97–106.
[56]
A. L. Spek, J. Appl. Crystallogr. 2003, 36, 7–13.
Received: October 2, 2009
Published Online: December 4, 2009
310
www.eurjic.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2010, 298–310