Reactivity of Pd(II) complexes containing the orthometallated C,C-chelating ligand C6H4-2-PPh2C(H)COCH2PPh3 towards deprotonating reagents. Part 2

Article abstract of DOI:10.1016/S0022-328X(00)00143-1

The reaction of [Pd(C₆H₄-2-PPh₂C(H)COCH₂PPh ₃)(μ-Cl)]₂(ClO₄)₂ (1) with the deprotonating reagent NBu₄OH (1:2.5 molar ratio, room temperature (r.t.)) and subsequently with monodentate ligands L (1:4 molar ratio) or bidentate ligands L-L (1:2 molar ratio) gives the cationic complexes [Pd(C₆H₄-2-PPh₂C(H)COCH=PPh ₃)(L)₂](ClO₄) (L=PPh₃ (2), H₂NCH₂CH=CH₂ (3)) or [Pd(C₆H₄-2-PPh₂C(H)COCH=PPh ₃)(L-L)](ClO₄) (L-L=dppm (4), Ph₂PCH₂PPh₂C(H)COPh (5), NC₅H₄-2-CO-N=PPh₃ (6)). In complexes 2-6 the orthometallated-ylide ligand is coordinated through the arylic carbon and through one ylidic carbon, and contains a free ylide fragment -C(H)=PPh₃. The reaction of 1 with NBu₄OH (1:2.5 molar ratio, r.t.) and with [PPh₂CH₂PPh₂CH₂COMe]ClO₄ (1:2 molar ratio) gives [Pd(PPh₂CH₂PPh₂CHC(O)Me)₂](ClO ₄)₂ (7) and the ylide-phosphonium salt [Ph₃P=C(H)COCH₂PPh₃]ClO₄. The reaction seems to occur through protonation of the orthometallated-ylide ligand by the acid protons of the phosphonium unit. All complexes were characterized on the basis of their spectroscopic data.

Full text of DOI:10.1016/S0022-328X(00)00143-1

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Journal of Organometallic Chemistry 602 (2000) 151–157
Reactivity of Pd(II) complexes containing the orthometallated
C,C-chelating ligand C6H4-2-PPh2C(H)COCH2PPh3 towards
deprotonating reagents. Part 2ꢀ
Susana Ferna´ndez, Rafael Navarro *, Esteban P. Urriolabeitia
Departamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n, Uni6ersidad de Zaragoza,
Consejo Superior de In6estigaciones Cient´ıficas, E-50009 Zaragoza, Spain
Received 31 January 2000; accepted 1 March 2000
Abstract
The reaction of [Pd(C6H4-2-PPh2C(H)COCH2PPh3)(m-Cl)]2(ClO4)2 (1) with the deprotonating reagent NBu4OH (1:2.5 molar
ratio, room temperature (r.t.)) and subsequently with monodentate ligands L (1:4 molar ratio) or bidentate ligands L–L (1:2
molar ratio) gives the cationic complexes [Pd(C6H4-2-PPh2C(H)COCHꢀPPh3)(L)2](ClO4) (L=PPh3 (2), H2NCH2CHꢀCH2 (3)) or
[Pd(C6H4-2-PPh2C(H)COCHꢀPPh3)(LꢁL)](ClO4) (LꢁL=dppm (4), Ph2PCH2PPh2C(H)COPh (5), NC5H4-2-COꢁNꢀPPh3 (6)). In
complexes 2–6 the orthometallated-ylide ligand is coordinated through the arylic carbon and through one ylidic carbon, and
contains
a free ylide fragment ꢁC(H)ꢀPPh3. The reaction of 1 with NBu4OH (1:2.5 molar ratio, r.t.) and with
[PPh2CH2PPh2CH2COMe]ClO4 (1:2 molar ratio) gives [Pd(PPh2CH2PPh2CHC(O)Me)2](ClO4)2 (7) and the ylide–phosphonium
salt [Ph3PꢀC(H)COCH2PPh3]ClO4. The reaction seems to occur through protonation of the orthometallated-ylide ligand by the
acid protons of the phosphonium unit. All complexes were characterized on the basis of their spectroscopic data. © 2000 Elsevier
Science S.A. All rights reserved.
Keywords: Palladium; Orthometallated; Deprotonation; Phosphoylides
1. Introduction
We have reported recently the synthesis [1] of Pd(II)
complexes containig the C,C-orthometallated ligand
[Pd(C6H4-2-PPh2C(H)COCH2PPh3)(L)(L%)]n+ (seeFig.1)
Fig. 2.
and their reactivity towards different deprotonating
reagents [2]. In all cases studied, the dangling phospho-
nium group ꢁCH2PPh3 was deprotonated, generating a
non-coordinated free ylide group ꢁC(H)ꢀPPh3, that is,
Fig. 1.
complexes of stoichiometry [Pd(C6H4-2-PPh2C(H)-
COCHꢀPPh3)(L)(L%)](n−1)+ could be obtained (see Fig.
2). The subsequent reaction of these last complexes
ꢀ Part 1, see Ref. [2].
* Corresponding author.
E-mail addresses: rafanava@posta.unizar.es (R. Navarro), este-
ban@posta.unizar.es (E.P. Urriolabeitia)
with an electrophilic metal center allowed to the obten-
tion of di- and trinuclear heterometallic derivatives, in
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S 0 0 2 2 - 3 2 8 X ( 0 0 ) 0 0 1 4 3 - 1

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S. Ferna´ndez et al. / Journal of Organometallic Chemistry 602 (2000) 151–157
which the orthometallated ylide group was acting as a
C,C,C-terdentate ligand, chelating the palladium centre
through two carbon atoms — the cyclometallated and
one ylidic — and bridging through the two ylidic car-
bon atoms the palladium and the other metal (see Fig.
3). This C,C,C-bonding mode was unknown for the
ylides. Although the orthometallation of the ylides is
not an unknown reaction [3,4], the contribution to the
chemistry of bis-ylides or related phosphino–ylides re-
mains scarce [5,6].
solution. Further stirring of this solution at room tem-
perature (r.t.) produces the precipitation of a pale yel-
low solid [7]. The solvent was evaporated and the
residue redissolved in methylene chloride, in which a
clear orange solution was obtained. This solution is the
starting point for further preparations, since its treat-
ment with monodentate ligands L (1:L=1:4 molar
ratio) or bidentate ligands LꢁL (1:L2=1:2 molar ratio)
allows the synthesis of complexes containing the or-
thometallated-free ylide ligand [C6H4-2-PPh2C(H)ꢁ
The reported [2] synthetic method of free ylide
C(O)ꢁC(H)ꢀPPh3] (see Eq. (1)).
(1)
derivatives
[Pd(C6H4-2-PPh2C(H)COCHꢀPPh3)-
(L)(L%)](n−1)+ could not be adequate if the ancillary
ligands L or L% possess acidic protons or could react
themselves with the deprotonating reagent. Thus, the
reaction of the starting complex [Pd(C6H4-2-
PPh2C(H)COCH2PPh3)(L)(L%)]n+ with the deprotonat-
ing reagent could result in competitive processes –
namely, the deprotonation of the phosphonium group
or the deprotonation or transformation of the ancillary
ligand. For instance, coordinated ligands such as dppm
(Ph2PCH2PPh2), allylamine or the phosphonium–ylides
PPh2CH2PPh2ꢀC(H)C(O)R are prone to react them-
selves with deprotonating agents such as NBu4OH or
Na[N(SiMe3)2].
Due to these facts, and also due to our interest in the
preparation of complexes containing the orthometal-
lated fragment and a free ylide group, we have devel-
oped an alternative method to synthesise derivatives
In a first attempt we have performed the reaction
with PPh3 (1:4 molar ratio). This reaction results in the
formation of the cationic mononuclear com-
plex [Pd(C6H4-2-PPh2C(H)ꢁC(O)ꢁC(H)ꢀPPh3)(PPh3)2]-
(ClO4) (2), which was isolated in analytical pure form
after evaporation of the CH2Cl2, washing of the residue
with water (in order to eliminate the tetrabutylammo-
nium salts) and with Et2O.
[Pd(C6H4-2-PPh2C(H)COCHꢀPPh3)(L)(L%)]m+
with
different L and L%. This method extends the scope of
stoichiometries available for different ligands, L and L%
in the aforementioned complexes. In this paper we
report the obtained results using this method and some
of its practical limitations.
The characterisation of [Pd(C6H4-2-PPh2C(H)ꢁC(O)ꢁ
C(H)ꢀPPh3)(PPh3)2](ClO4) (2) has been carried out by
analytical and spectroscopic methods. The presence of
the free ylide unit ꢁC(O)ꢁC(H)ꢀPPh3 is inferred from
the IR spectrum since the stretch wCO (ylide) appears at
1524 cm−1, a typical region for this situation [2]. The
NMR spectra of 2 provide more structural information.
2. Results and discussion
The reaction of [Pd(C6H4-2-PPh2C(H)ꢁC(O)ꢁCH2-
PPh3)(m-Cl)]2(ClO4)2 (1) with the deprotonating reagent
NBu4OH (1:2.5 molar ratio) in MeOH results in a fast
colour change from yellow to orange and in the gradual
dissolution of the initial suspension to give an orange
1
The H-NMR spectrum shows a doublet resonance at
3.80 ppm, attributed to the methine proton [ꢁC(H)ꢀP]
2
with a value of the coupling constant JPꢁH of 26 Hz,
the 31P{1H}-NMR spectrum shows a doublet resonance
at 15.11 ppm attributed to the phosphorus of the free
ylide group [ꢁC(H)ꢀP], and the 13C{1H}-NMR spec-
trum shows a doublet of quartets at 56.07 ppm, at-
tributed to the ylidic carbon [ꢁC(H)ꢀP]. The value of
1
the coupling constant JPꢁC=108 Hz is typical for the
presence of the free ylide unit [2].
The observation of four different resonances in the
31P{1H}-NMR spectrum (relative intensities 1:1:1:1)
shows the presence of four chemically unequivalent P
atoms in the molecule, two of the C,C-chelating or-
Fig. 3.

S. Ferna´ndez et al. / Journal of Organometallic Chemistry 602 (2000) 151–157
153
Scheme 1.
thometallated ylide and two mutually cis PPh3 ligands.
The orthometallated carbon atom appears at 171.51
ppm as a doublet of doublets of doublets, and the
However, the easiness of synthesis of 2 contrast with
the impossibility found in the synthesis of the related
[Pd(C6H4 - 2 - PPh2C(H)ꢁC(O)CH2PPh3)(PPh3)2](ClO4)2.
Thus, the reaction of [Pd(C6H4-2-PPh2C(H)ꢁC(O)CH2-
PPh3)(NCMe)2](ClO4)2 with two equivalents of PPh3 in
CH2Cl2 results in the substitution of the NCMe ligand
trans to the ylidic carbon and the formation of
[Pd(C6H4-2-PPh2C(H)ꢁC(O)CH2PPh3)(NCMe)(PPh3)]-
(ClO4)2, already described by us [1], together with some
amounts of the hydrolysis products [Pd(m-OH)-
(PPh3)2](ClO4)2 — characterised by comparison with
the reported spectral data [14] — and mono-ylide
[Ph3PꢀC(H)COCH2PPh3]ClO4.
2
values of the coupling constants JPtransC=123 Hz and
2JPcisC=34 Hz show clearly the mutual cis arrangement
of the phosphine ligands.
It is interesting to remark the presence in 2 of two
mutually cis phosphine ligands which are also trans to
two carbon atoms. According with the antisymbiotic
behaviour of the Pd(II) centre [8–11] and the transpho-
bic effect [12], or reluctance of a phosphine ligand to be
in trans to an arylic carbon atom, the complex 2 should
be really unstable. However, complex 2 is very stable
and the presence of the phosphine trans to the aryl
carbon atom is not only stable but sometimes can not
be avoided. For instance, complex 2 can be identified in
the reaction of [Pd(C6H4-2-PPh2C(H)COCH2PPh3)(Cl)-
(PPh3)](ClO4) with Na[N(SiMe3)2]. We have reported
recently [2] that this reaction gave a mixture of prod-
ucts which were not identified: complex 2 is one of
them. An additional example is provided by the fact
In the same way as that described for 2, 1 reacts with
NBu4OH (1:2.5 molar ratio) and allylamine
H2NꢁCH2ꢁC(H)ꢀCH2 (1:4 molar ratio) (see Eq. (1))
resulting in the formation of [Pd(C6H4-2-PPh2C(H)ꢁ
C(O)C(H)ꢀPPh3)(NH2ꢁCH2ꢁC(H)ꢀCH2)2](ClO4) (3) as
a yellow solid, which has been characterised on the
basis of its analytical and spectroscopic data. The IR
spectrum of 3 shows the w(CO) of the ylide at 1511
cm−1 and also shows absorptions at 3299 and 3269
cm−1 corresponding to the w(NH) stretch, suggesting
the presence of coordinated amine. The 31P{1H}-NMR
spectrum shows the presence of an AX spin system
centred at 20.32 ppm (P-in-ring) and 15.33 ppm
that
[Pd(C6H4-2-PPh2C(H)COCH2PPh3)(Cl)(PPh3)]-
(ClO4) exist as a single isomer [1] with the PPh3 trans to
the ylidic carbon. However its deprotonated, neutral,
form [Pd(C6H4-2-PPh2C(H)COCHꢀPPh3)(Cl)(PPh3)] is
obtained as a mixture of two geometric isomers [2], cis
and trans, with the most abundant being that contain-
ing the PPh3 trans to the orthometallated carbon. A
plausible explanation for the stability of 2 could be that
the reductive elimination would be slow owing to the
high energy of the derived four-membered organic
product [13].
1
[ꢁC(H)ꢀP]. The H-NMR spectrum shows the expected
two sets of resonances attributed to the chemically
unequivalent allylamine groups and a doublet of dou-
blets at 3.64 ppm attributed to the free ylidic proton
[ꢁC(H)ꢀP]. This last resonance shows a value of the
2
coupling constant JPꢁH of 24.3 Hz. All these facts

154
S. Ferna´ndez et al. / Journal of Organometallic Chemistry 602 (2000) 151–157
confirm the proposed stoichiometry and the validity of
the synthetic method.
to the orthometallated carbon atom. This arrangement
of ligands can be inferred from the 13C{1H}-NMR in
which the orthometallated carbon appears at 175.58
ppm as a doublet of doublet of doublets. The value of
We have also attempted reactions with monodentate
ligands but using a lower molar ratio Pd:ligand (1:2) in
order to obtain mononuclear derivatives with only one
L coordinated and aiming to force the coordination of
the carbonyl oxygen in the position cis to the coordi-
nated ylidic carbon. However, these reactions did not
give the expected results. For instance, when L=PPh3,
the reaction results in the formation of a complex
mixture in which the only identified product was 2. Due
to this fact, these type of reactions were not investi-
gated further.
2
the large coupling constant JPtransC=133 Hz is indica-
tive of a P-trans-to-Caryl disposition [1]. In addition,
this geometric isomer should be obtained as the mixture
of two diastereoisomers (RR/SS) and (RS/SR) but
only one is detected. It seems clearly established that in
five-membered metallacycles containing a bulky sub-
stituent, this substituent is directed to an axial disposi-
tion. For instance, in complexes with the C,N-chelating
ligand C6H4ꢁC(H)MeꢁNMe2, the a-methyl group is
invariably in an axial position [15–20] and in com-
plexes with the P,C-bonded phosphino–ylide ligand
Ph2PCH2PPh2ꢀC(H)COR, the C(O)R group is also ax-
ially directed [21–23]. Following that, we propose a
structure for complex 5 as that represented in Fig. 4, in
which both bulky groups attached to the ylidic carbons
are in an axial disposition but in opposite sides of the
molecular plane, in order to minimise steric repulsions,
and both hydrogen atoms are in equatorial disposi-
tions. Additional evidences can be obtained from the
1H–1H NOESY spectrum, in which a strong NOE
cross-peak is observed between the resonance at 4.91
ppm (attributed to the ylidic proton PdꢁC(H)ꢁC(O)Ph)
and the resonance at 8.29 ppm (attributed to the Hortho
proton of the metallated C6H4 ring). Obviously, Fig. 4
represents only one enantiomer of 5 and the product as
a whole is the racemic mixture. Once again, complex 5
represents an example of a stable P-trans-to-Caryl ar-
rangement of ligands.
Other chelating ligands, symmetrical and asymmetri-
cal, were employed with successful results. The reaction
of 1 with NBu4OH and dppm results in the formation
of [Pd(C6H4-2-PPh2C(H)ꢁC(O)C(H)ꢀPPh3)(Ph2PCH2-
PPh2)](ClO4) (4) as a white solid, and the reaction with
the phosphino–ylide Ph2PCH2PPh2ꢀC(H)COPh gives
[Pd(C6H4 - 2 - PPh2C(H)ꢁC(O)C(H)ꢀPPh3)(Ph2PCH2-
PPh2C(H)C(O)Ph)](ClO4) (5). Complex 4 was obtained
in analytically pure form after concentration of the
CH2Cl2 solution and precipitation with Et2O, while 5
was recrystallized from MeOH. The characterisation of
4 and 5 was carried out by examination of the same
parameters as those employed for 2 and 3, that is, (i)
the position of the w(CO) of the ylide; (ii) the chemical
shift of the methine resonance [ꢁC(H)ꢀP] and the value
2
1
of the coupling constant JPꢁH in the H-NMR spec-
trum; (iii) the chemical shift of the ylidic phospohorus
[ꢁC(H)ꢀP] in the 31P{1H}-NMR spectrum; and (iv) the
chemical shift of the ylidic carbon [ꢁC(H)ꢀP] and the
1
value of the coupling constant JPꢁC in the 13C{1H}-
On the other hand, 1 reacts cleanly with NBu4OH
and the imino–phosphorane NC5H4-2-C(O)ꢁNꢀPPh3
resulting in the formation of the mononuclear deriva-
tive [Pd(C6H4-2-PPh2C(H)ꢁC(O)C(H)ꢀPPh3)(NC5H4-2-
C(O)ꢁNꢀPPh3)](ClO4) (6), according with its elemental
analysis and mass spectrum. This iminophosphorane
ligand has shown to behave as a versatile coordinating
group, and three different coordination modes has been
characterised in Pd(II) and Pt(II) complexes [23]. In the
case of complex 6, the comparison of the spectral data
(see Section 4) with those reported previously [23] al-
lows to determine that the iminophosphorane ligand is
N,N-coordinated. The absorption corresponding to the
NMR spectrum (see Section 4).
Complex 4, as well as complexes 2 and 3, contains
only one chiral centre and was obtained as the racemic
mixture. Complex 5 could be obtained as the mixture of
two geometric isomers, P-trans-to-Cylide and P-trans-to-
Caryl, each geometric isomer containing two chiral cen-
ters, thus expecting a maximum of four diastereo-
isomers (each one as the racemic mixture of two enan-
tiomers). However, the spectroscopic data for 5 show
the presence of a single diastereoisomer in which the
phosphino–ylide is P,C-bonded to the palladium cen-
tre, as represented in Fig. 4, being the phosphorus trans
wCO of the iminophosphorane appears at 1578 cm−1
,
and the 31P{1H}-NMR spectrum shows the resonance
corresponding to the ꢁNꢀPPh3 group as a singlet at
25.75 ppm. The presence of the orthometallated-free
ylide ligand can be inferred from the spectroscopic data
as for complexes 2–5. Two geometric isomers can also
be expected for complex 6, that with N(py)-trans-to-
Caryl and that with N(py)-trans-to-Cylide. The 1H–1H
NOESY spectrum provides the additional structural
information because a strong NOE interaction between
the H6 proton of the pyridine ligand and the ylidic
Fig. 4.

S. Ferna´ndez et al. / Journal of Organometallic Chemistry 602 (2000) 151–157
155
3. Conclusions
The reactivity of 1 with NBu4OH and different
mono- and bidentate ligands has been explored. This
type of reaction allows the synthesis, in very mild
conditions, of complexes containing the orthometal-
lated fragment and the dangling free ylide group with
ligands, which could also react themselves with the
deprotonating reagent. Moreover, the method tolerates
the presence of functional groups attached to the donor
atom.
Fig. 5.
proton reveals their mutual cis disposition, as repre-
sented in Fig. 5. Finally, since complex 6 has only a
chiral center, the complex is obtained as the racemic
mixture.
4. Experimental
When complex 1 is allowed to react with NBu4OH
and the phosphine–phosphonium salt [Ph2PCH2PPh2-
CH2COMe]ClO4 in the usual molar ratios, an interest-
ing redistribution reaction occurs (see Scheme 1),
instead of the expected P-coordination of the two phos-
phine moieties. The reaction was performed in MeOH–
CH2Cl2 (see Section 4) and in the subsequent workup
and crystallisation from MeOH two fractions were
separated. The first fraction, insoluble in MeOH, con-
tains a small quantity of unreacted phosphonium and a
product characterised as [Pd(PPh2CH2PPh2CHC-
(O)Me)2](ClO4)2 (7) on the basis of its analytical and
spectral data (see Section 4). The second fraction, pre-
cipitated with Et2O, contains almost exclusively the
ylide–phosphonium salt [Ph3PꢀC(H)C(O)CH2-PPh3]-
(ClO4) [1].
Product 7 shows, in the IR spectrum, a strong ab-
sorption at 1637 cm−1, attributed to the wCO of the
carbonyl group ꢁC(H)ꢁC(O)ꢁMe. No absorptions were
found around 1520 cm−1, typical region of the ylide
ꢁC(H)ꢁC(O)ꢁC(H)ꢀPPh3. The 31P{1H}-NMR spectrum
shows the presence of an AA%XX% spin system and the
1H-NMR show the resonances attributed to the ylidic
proton PdꢁC(H), the diastereotopic protons of the
PCH2P fragment and a doublet for the methyl group
ꢁC(O)ꢁMe.
4.1. Safety note
Caution! Perchlorate salts of metal complexes with
organic ligands are potentially explosive. Only small
amounts of these materials should be prepared and they
should be handled with great caution (see Ref. [24]).
4.2. General procedures
Solvents were dried and distilled under nitrogen be-
fore use: diethyl ether and tetrahydrofuran over ben-
zophenone ketyl, dichloromethane and chloroform over
P2O5, acetonitrile over CaH2, methanol over magne-
sium and n-hexane and toluene over sodium. Elemental
analyses were carried out on a Perkin–Elmer 240-B
microanalyser. Infrared spectra (4000–200 cm−1) were
recorded on a Perkin–Elmer 883 infrared spectrophoto-
meter from Nujol mulls between polyethylene sheets.
1H (300.13 MHz), 13C{1H} (75.47 MHz) and 31P{1H}
(121.49 MHz)-NMR spectra were recorded in CDCl3 or
CD2Cl2 solutions at r.t. (unless otherwise stated) on a
Bruker ARX-300 spectrometer; H and 13C{1H} were
1
referenced using the solvent signal as internal standard
and 31P{1H} was externally referenced to H3PO4 (85%).
The two dimensional H–1H NOESY experiments for
1
complexes 5 and 6 were performed at a measuring
frequency of 300.13 MHz. The data were acquired into
a 512×1024 matrix, and then transformed into 1024×
1024 points using a sine window in each dimension.
The mixing time was 400 ms. Mass spectra (positive ion
FAB) were recorded on a V.G. autospec spectrometer
from CH2Cl2 solutions. The starting complex [Pd(m-
Cl)(C6H4-2-PPh2C(H)COCH2PPh3)]2(ClO4)2 (1), was
prepared according to published methods [1].
With these data we propose that 7 has a geometry
P-cis-to-P since the reaction should begin by mutual cis
P-coordination of the two phosphine ends of the phos-
phine–phosphonium ligands (intermediate A in Scheme
1) and then protonation of the PdꢁCaryl bond by the
acidic phosphonium group. The bis-ylide thus gener-
ated can deprotonate the remaining phosphonium moi-
ety, thus forming a new ylide which coordinates
immediately giving 7, and obtaining [Ph3PꢀC(H)-
C(O)CH2PPh3](ClO4) as the protonation product of the
bis-ylide. In this case, the acidity of the protons of the
phosphonium group is strong enough to promote unde-
sirable side reactions. This strong acidity could be a
limiting factor when using this method and could re-
duce its scope of applicability.
4.3. [Pd(C6H4-2-PPh2C(H)COC(H)ꢀPPh3)-
(PPh3)2](ClO4) (2)
To
a
yellow suspension of [Pd(m-Cl)(C6H4-2-
PPh2C(H)COCH2PPh3)]2(ClO4)2 (1) (0.160 g, 0.097

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mmol) in MeOH (15 ml), was added an aqueous solu-
tion of NBu4OH (40% wt) (159 ml, 0.243 mmol). The
suspension becomes orange and after 5 min all solids
were dissolved. This solution was stirred for 1 h at r.t.,
and during this time a pale yellow solid precipitated.
The resulting suspension was evaporated to dryness and
the residue extracted with CH2Cl2 (20 ml), giving a
yellow solution. Any remaining solid material at this
stage was filtered and discarded. To this solution was
added PPh3 (0.102 g, 0.390 mmol) and the solution
stirred for 2 h at r.t. After this time the solvent was
evaporated to dryness and the residue was washed with
H2O (2×20 ml) and Et2O (2×20 ml), giving 2 as a
yellow solid. Obtained: 0.190 g (74% yield).
(dd, C(H)ꢀP, 1JPC=116, 3JPꢁC=9 Hz), 35.23 (dd,
1 3
C(H)Pd, JPꢁC=47, JPꢁC=18 Hz).
4.5. [Pd(C6H4-2-PPh2C(H)COC(H)ꢀPPh3)-
(Ph2PCH2PPh2)](ClO4) (4)
Complex 4 was synthesised in the same way as those
described for 2: 1 (0.158 g, 0.096 mmol), NBu4OH (157
ml, 0.240 mmol), Ph2PCH2PPh2 (0.074 g, 0.192 mmol).
Obtained: 0.191 g (85% yield).
Anal. Calc. for C64H53ClO5P4Pd (1167.87 g mol−1):
C, 65.82; H, 4.57. Found: C, 65.13; H, 4.26%. MS [m/z,
%]: 1067 [(M−ClO4)+, 100%]. IR (w, cm−1): 1511 (wCO
1
ylide). H-NMR (CDCl3): l 7.94–6.88 (m, 49H, Ph+
Anal. Calc. for C75H61ClO5P4Pd (1308.06 g mol−1):
C, 68.87; H, 4.70. Found: C, 68.28; H, 4.36%. MS [m/z,
%]: 945 [(MꢁPPh3ꢁClO4)+, 15%]. IR (w, cm−1): 1524
C6H4), 4.39 (m, 1H, PdꢁC(H)P), 4.16 (ddd, 1H, PCH2P,
2JHꢁH=16, 2JPꢁH=10, 2JPꢁH=8 Hz), 3.88 (dt, 1H,
2
2
PCH2P, JPꢁH=9 Hz), 3.37 (d, 1H, C(H)=P, JPꢁH
=
1
(wCO ylide). H-NMR (CD2Cl2): l 7.88–6.66 (m, 59H,
24.6 Hz). 31P{1H}-NMR (CDCl3): l 25.18 (ddd, C6H4-
3
Ph+C6H4), 4.03 (dddd, 1H, C(H)ꢁPd, JPtransꢁH=14,
3
3
4
2-PPh2, JPꢁPtrans=26, JPꢁPcis=23, JPꢁP=8 Hz), 14.50
3
4
2JPꢁH=7.2, JPcisꢁH=5.1, JPꢁH=2.1 Hz), 3.80 (d, 1H,
4
(d, C(H)ꢀPPh3, JPꢁP=8 Hz), −19.36 (dd, PPh2 cis to
C(H)ꢀP, 2JPꢁH=26 Hz). 31P{1H}-NMR (CD2Cl2): l
2
3
C ylide, JPꢁP=49, JPꢁP=23 Hz), −30.54 (dd, PPh3
2
3
35.73 (dd, PPh3 trans to C ylide, JPꢁP=31, JPꢁP=20
Hz), 26.75 (dd, PPh3 cis to C ylide, 3JPꢁP=27 Hz),
26.11 (ddd, C6H4-2-PPh2, 3JPꢁP=27, 4JPꢁP=6 Hz),
15.11 (d, C(H)ꢀPPh3). 13C{1H}-NMR (CD2Cl2): l
186.24 (quart, CO, 2JPꢁC$3JPꢁC=4.6 Hz), 171.51 (ddd,
trans to C ylide, JPꢁP=49, JPꢁP=26 Hz). 13C{1H}-
NMR (CDCl3): l 188.11 (m, CO), 168.76 (dd, C1,
C6H4, 2JPtransC=130, 2JPcisC=26 Hz), 141.99–125.66
(Ph+C6H4), 44.81 (m, C(H)Pd).
2
3
C1, C6H4, 2JPtransC=123, 2JPcisC=34, 2JPC=7.3 Hz),
1
141.56–125.10 (Ph+C6H4), 56.07 (dq, C(H)ꢀP, JPC
=
4.6. [Pd(C6H4-2-PPh2C(H)COC(H)ꢀPPh3)-
(Ph2PCH2PPh2C(H)COPh)](ClO4) (5)
108.1, JPꢁC$4JPꢁC=3.8 Hz), 49.14 (ddd, C(H)Pd,
3
1JPꢁC=63.8, JPtransꢁC=43, JPcisꢁC=17.1 Hz).
2
2
Complex 5 was synthesised in the same way as those
described for 2 except that the product was recrys-
tallised from MeOH: 1 (0.158 g, 0.096 mmol), NBu4OH
(157 ml, 0.240 mmol), Ph2PCH2PPh2ꢀC(H)COPh (0.096
g, 0.192 mmol). Obtained: 0.185 g (75% yield).
4.4. [Pd(C6H4-2-PPh2C(H)COC(H)ꢀPPh3)-
(H2NCH2CHꢀCH2)2](ClO4) (3)
Complex 3 was synthesised in the same way as those
described for 2: 1 (0.158 g, 0.096 mmol), NBu4OH (157
ml, 0.240 mmol), allylamine (28 ml, 0.385 mmol). Ob-
tained: 0.133 g (77% yield).
Anal. Calc. for C72H59ClO6P4Pd (1286.00 g mol−1):
C, 67.24; H, 4.62. Found: C, 66.85; H, 4.25%. MS [m/z,
%]: 1185 [(M−ClO4)+, 100%]. IR (w, cm−1): 1605
1
(wCOPh ylide), 1505 (wCOCHꢀP ylide). H-NMR (CDCl3):
4
Anal. Calc. for C45H45ClN2O5P2Pd (897.66 g mol−1):
C, 60.21; H, 5.05; N, 3.12. Found: C, 59.21; H, 4.97;
N, 2.65%. MS [m/z, %]: 683 [(M−2NH2CH2CHCH2ꢁ
ClO4)+, 100%]. IR (w, cm−1): 3299, 3269 (wNH), 1511
l 8.29 (t, 1H, H6, C6H4, JPꢁH=6.9 Hz), 8.15–6.65 (m,
2
53H, Ph+C6H4), 4.91 (t, 1H, PdꢁC(H)COPh, JPꢁH
=
4JPꢁH=5 Hz), 4.74 (ddd, 1H, PCH2P, 2JPꢁH=17,
2JHꢁH=15, 2JPꢁH=9 Hz), 4.01 (dt, 1H, PCH2P,
1
(wCO ylide). H-NMR (CDCl3): l 8.04–6.99 (m, 29H,
2JPꢁH=9 Hz), 3.53 (dt, 1H, C(H)ꢁPd, 2JPꢁH=9.9,
2
Ph+C6H4), 5.72 (m, 1H, CHcent, allyl), 5.30, (m, 1H,
4JPꢁH=4JHꢁH=5 Hz), 3.02 (d, 1H, C(H)=P, JPꢁH
=
CHcent, allyl), 5.05 (d, 1H, CHtrans, allyl, 3JHꢁH=16
25.2 Hz). 31P{1H}-NMR (CDCl3): l 36.77 (d, PdꢁPPh2,
3
4
Hz), 4.93 (d, 1H, CHcis, allyl, JHꢁH=10.5 Hz), 4.73 (d,
2JPꢁP=73 Hz), 25.27 (d, C6H4-2-PPh2, JPꢁP=36 Hz),
3
1H, CHtrans, allyl, JHꢁH=17 Hz), 4.65 (d, 1H, CHcis,
15.78
(dd,
PdꢁC(H)(COPh)PPh2),
14.33
(s,
3
2
allyl, JHꢁH=10.2 Hz), 3.91 (dd, 1H, C(H)ꢁPd, JPꢁH
=
C(H)ꢀPPh3). 13C{1H}-NMR (CDCl3): l 196.11 (d,
4
2
2
2
6, JPꢁH=2.1 Hz), 3.64 (dd, 1H, C(H)ꢀP, JPꢁH=24.3,
4JPꢁH=0.9 Hz), 3.36 (m, 1H, NH2), 3.15 (m, 2H,
NCH2), 2.97 (m, 1H, NH2), 2.78 (m, 4H, NCH2+
NH2). 31P{1H}-NMR (CDCl3): l 20.32 (d, C6H4-2-
PPh2, 4JPꢁP=11 Hz), 15.33 (d, C(H)ꢀPPh3).
COPh, JPꢁC=3.2 Hz), 187.55 (t, CO, JPꢁC=4.2 Hz),
175.58 (ddd, C1, C6H4, 2JPtransC=133, 2JPcisC=32,
2JPC=6.3 Hz), 139.06–121.51 (Ph+C6H4), 54.02 (dd,
C(H)ꢀP, 1JPꢁC=108, 3JPꢁC=5.5 Hz), 41.02 (ddd,
1
2
3
C(H)Pd, JPꢁC=38, JPꢁC=17.3, JPꢁC=5.4 Hz), 38.83
1
13C{1H}-NMR (CDCl3):
l
189.89 (pseudot, CO,
(d, PdꢁC(H)COPh, JPꢁC=57 Hz), 33.20 (dd, PCH2P,
2JPꢁC=4 Hz), 164.16 (d, C1, C6H4, JPC=23 Hz), 46.77
1JPꢁC=66, JPC=11 Hz).
2
1

S. Ferna´ndez et al. / Journal of Organometallic Chemistry 602 (2000) 151–157
157
3
2
4.7. [Pd(C6H4-2-PPh2C(H)COC(H)ꢀPPh3)-
(NC5H4-2-COꢁNꢀPPh3)](ClO4) (6)
spin system, 2JAꢁX=55, JAꢁX%=ꢁ12, JAꢁA%=29.64,
4JXꢁX%=0 Hz).
Complex 6 was synthesised in the same way as those
described for 2: 1 (0.158 g, 0.096 mmol), NBu4OH (157
ml, 0.240 mmol), NC5H4-2-COꢁNꢀPPh3 (0.073 g, 0.192
mmol). Obtained: 0.200 g (90% yield).
Acknowledgements
Funding by the Direccio´n General de Ensen˜anza
Superior (Spain, project PB95-0003-C02-1) is gratefully
acknowledged, and we thank Professor J. Fornie´s for
invaluable logistical support.
Anal. Calc. for C63H50ClN2O6P3Pd (1165.87
g
mol−1): C, 64.90; H, 4.32; N, 2.40. Found: C, 64.28; H,
4.33; N, 2.54%. MS [m/z, %]: 1065 [(M−ClO4)+,
100%]. IR (w, cm−1): 1578 (wCO iminophosphorane),
1
1525 (wCO ylide). H-NMR (CDCl3): l 8.69 (d, 1H, H6,
3
3
py, JHꢁH=4.8 Hz), 8.55 (d, 1H, H3, py, JHꢁH=7.2
References
3
4
Hz), 8.02 (td, 1H, H4, py, JHꢁH=7.2, JHꢁH=1.2 Hz),
7.87–7.07 (m, 42H, Ph+C6H4), 6.90 (m, 1H, H5, py),
6.83 (m, 1H, H5%, C6H4), 6.63 (d, 1H, H6%, C6H4,
3JHꢁH=7.8 Hz), 3.83 (dd, 1H, C(H)ꢁPd, 2JPꢁH=6.6,
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4JPꢁH=4.5 Hz), 3.63 (d, 1H, C(H)ꢀP, JPꢁH=24.9 Hz).
2
31P{1H}-NMR (CDCl3): l 27.83 (d, C6H4-2-PPh2,
4JPꢁP=1.6 Hz), 25.75 (s, ꢁNꢀPPh3), 14.66 (d,
C(H)ꢀPPh3). 13C{1H}-NMR (CDCl3): l 187.98 (t, CO,
2JPꢁC=2.6 Hz), 177.40 (d, COꢁNꢀP, 2JPꢁC=8 Hz),
3
161.52 (d, C2, py, JPꢁC=24 Hz), 153.54 (d, C1, C6H4,
2JPC=24 Hz), 149.76 (s, C6, py), 139.22 (s, C4, py),
1
137.30 (d, C2, C6H4, JPꢁC=114 Hz), 135.08 (d, C6H4,
J
PꢁC=16 Hz), 134.22 (d, C6H4, JPꢁC=9 Hz), 133.59–
128.76 (m, Ph+C6H4), 128.15, 127.17 (2s, C3+C5, py),
126.40 (d, Ph, Cipso, JPꢁC=86 Hz), 125.13 (d, Ph, Cipso
PꢁC=96 Hz), 125.09 (d, C6H4, JPꢁC=12 Hz), 54.05
,
J
(dd, C(H)ꢀP, 1JPC=109, 3JPꢁC=5.6 Hz), 33.97 (dd,
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3
C(H)Pd, JPꢁC=42, JPC=17 Hz).
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4.8. cis-[Pd(Ph2PCH2PPh2CHCOMe)2](ClO4)2 (7)
Complex 7 was synthesised in the same way as those
described for 2, except that the product was precipi-
tated in MeOH after washing with water: 1 (0.158 g,
0.096 mmol), NBu4OH (157 ml, 0.240 mmol),
[Ph2PCH2PPh2CH2COMe](ClO4) (0.207 g, 0.384
mmol). Obtained: 0.270 g. This product was character-
ised as a mixture of 7 and the phosphonium–ylide
[Ph3PꢀC(H)COCH2PPh3]ClO4. Pure 7 was obtained by
recrystallisation of this mixture from CH2Cl2–MeOH.
Obtained: 0.126 g (55% yield).
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Anal. Calc for C56H52Cl2O10P4Pd.CH2Cl2 (1271.122 g
mol−1): C, 53.85; H, 4.28. Found: C, 54.27; H, 4.01%.
MS [m/z, %]: 1087 [(M−ClO4)+, 6%]. IR (w, cm−1):
1
1637 (wCO). H-NMR (CD2Cl2): l 7.84–7.11 (m, 20H,
Ph), 5.75 (m, 1H, C(H)Pd), 4.66 (ddd, 1H, PCH2P,
2JHꢁH=15.6, 2JPꢁH=18, 2JPꢁH=11.1 Hz), 4.32 (m,
4
broad, PCH2P, 1H), 2.14 (d, 3H, ꢁC(O)Me, JPꢁH=0.9
Hz). 31P{1H}-NMR (CD2Cl2): l 41.17, 32.05 (AA%XX%
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