Direct ortho-palladation of 2-phenyl-2-oxazoline: Crystal structure of Cl2Pd(OCH2CH2N=C-Ph)2 and Cl(PPh3)Pd(OCH2CH2N=C-C6H 4)

Article abstract of DOI:10.1016/S0022-328X(00)00133-9

Direct ortho-palladation of sterically non-hindered 2-phenyl-2-oxazoline (1) using Pd(OAc)₂ and AcONa in AcOH provided di-μ-acetatobis-[2-(2-oxazolinyl)phenyl,1-C,3-N]dipalladium(II) (3a) in a yield of 63%. Dimeric complex 3a was converted into

Full text of DOI:10.1016/S0022-328X(00)00133-9

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Journal of Organometallic Chemistry 603 (2000) 86–97
Direct ortho-palladation of 2-phenyl-2-oxazoline
¸¹¹¹¹¹¹¹º
Crystal structure of Cl2Pd(OCH2CH2NꢀCꢁPh)2 and
¸¹¹¹¹¹¹¹º
Cl(PPh3)Pd(OCH2CH2NꢀCꢁC6H4)
Irina P. Smoliakova a,*, Kristopher J. Keuseman a,1, Dana C. Haagenson a,
Dawn M. Wellmann a,2, Peter B. Colligan a,3, Nadezhda A. Kataeva b,
Andrey V. Churakov b, Lyudmila G. Kuz’mina b, Valery V. Dunina c
a Chemistry Department, Uni6ersity of North Dakota, PO Box 9024, Grand Forks, ND 58202, USA
b N.S. Kurnako6 Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky Prospect 31, Moscow 117907, Russia
c Department of Chemistry, M.V. Lomonoso6 Moscow State Uni6ersity, Leninskie Gory, V-234, Moscow 119899, Russia
Received 11 January 2000; received in revised form 18 February 2000
Abstract
Direct ortho-palladation of sterically non-hindered 2-phenyl-2-oxazoline (1) using Pd(OAc)2 and AcONa in AcOH provided
di-m-acetatobis-[2-(2-oxazolinyl)phenyl,1-C,3-N]dipalladium(II) (3a) in a yield of 63%. Dimeric complex 3a was converted into the
corresponding m-chloro analog (3b) by the reaction with LiCl in acetone in quantitative yield. Compound 3b was also obtained
in 90% yield by the ligand exchange reaction of oxazoline (1) with dimeric ortho-palladated complex of N,N-dimethylbenzylamine
in a AcOH–CHCl3 mixture at 50°C. The same reaction at room temperature provided the coordination complex dichlorobis-(2-
phenyl-2-oxazoline)palladium(II) (2); the use of toluene in this reaction (50°C) led to the formation of chloro[N,N-dimethylbenzy-
lamino]-(2-phenyl-2-oxazoline)palladium(II) (5). Dimer 3b reacted with 2,4-pentadionate and PPh3 to yield the corresponding
mononuclear derivatives 6 and 7, respectively. The structures of coordination complex 2 and phosphane adduct 7 were confirmed
by X-ray diffraction analysis. Compound 2 has a centrosymmetric structure with strictly planar coordination environment of the
palladium center and a close above-plane approach of the ortho-CꢁH bond to the metal center. In adduct 7, both the palladium
coordination sphere and palladacycle are nearly planar. © 2000 Elsevier Science S.A. All rights reserved.
Keywords: Cyclopalladated complexes; 2-Phenyl-2-oxazoline; X-ray study
1. Introduction
oxazolines [4] or other heteroatom-functionalized
bidentate oxazolines [5] containing only metalꢁ
heteroatom bonds. The use of homochiral cyclopalla-
dated oxazoline-based complexes in catalysis has also
been studied. These organometallic catalysts are of the
N,C,N (A, Fig. 1) and C,N types (B, Fig. 1) [6,7].
Analysis of the results achieved using these complexes
reveal the greater catalytic efficiency of the latter struc-
tural type and a high potential of the oxazolinyl group
as a chirality inductor in general. It is also known that
optically active palladacycles of the C,N-type derived
from amines and imines provide very high stereoselec-
tivity in allylic imidate rearrangements [8,9]. These re-
ports prompted us to initiate a study on preparation
Recently, optically active oxazoline-derived com-
plexes of Pd(II) [1] and other metals [2] have attracted
a great deal of attention due to their high efficiency in
enantioselective catalysis [1–5]. The majority of these
promising catalysts (or pre-catalysts) are simple coor-
dination compounds of bisoxazolines [3], phosphino–
* Corresponding author. Fax: +1-701-777231.
E-mail address: ismoliakova@mail.chem.und.nodak.edu (I.P. Smo-
liakova)
1 Undergraduate researcher.
2 Undergraduate researcher.
3 Undergraduate researcher.
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(00)00133-9

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87
Fig. 1. Types of known cyclopalladated complexes of oxazolines.
and use of C,N-type cyclopalladated complexes of oxa-
2. Results and discussion
zolines including homochiral ones.
Preparation of oxazoline-based palladacycles has
not been a simple task. Direct palladation using
Pd(OAc)2 was achieved in a moderate (45–60%)
[10,11] to high (82–98%) [12,13] yield only for trisub-
stituted oxazolines furnishing achiral complexes of
types C and D (Fig. 1). In the case of disubstituted
mono- and bisoxazoline ligands, initial attempts of
direct palladation failed. The target complexes of
types A and B have been prepared by transmetalla-
tion reactions of organolithium [6] and organotin [14]
intermediates or by oxidative addition of the corre-
sponding aryl [6] and ferrocenyl [7] halides to a palla-
dium(0) compound. Only two examples of successful
direct ortho-palladation of disubstituted oxazoline lig-
ands have been reported. In one case, a ligand bear-
ing a metallocene fragment was converted to complex
E (Fig. 1) upon treatment with Pd(OAc)2 in AcOH
[15]. In the other study, a bisoxazoline derivative re-
acted with Na2PdCl4 in boiling aq. MeOH to yield
complex F (Fig. 1) [16].
2.1. Cyclopalladation reactions
Many methods for the preparation of cyclopalla-
dated complexes through direct activation of CꢁH
bonds have been reported and reviewed [19–23]. They
differ by palladation agent, base, reagents’ ratio, sol-
vent polarity, temperature, and reaction time. One of
the most common compounds used for palladation is
Na2PdCl4. We found that the application of an equimo-
lar amount of this rather weak electrophilic reagent in
the reaction with 2-phenyl-2-oxazoline (1) in MeOH
(room temperature (r.t.)) in the presence of AcONa as
a base led to the formation of a bis(oxazoline) coordi-
nation complex (2, 70%) with no traces (1H-NMR data)
of the desired cyclopalladated compound (3a). The
former was also obtained in 82% yield by reacting
Na2PdCl4 with ligand 1 in a ratio of 1:2 in MeOH at
r.t. (Scheme 1). It is noteworthy that pure compound 2
was stable, whereas the crude product decomposed
rather quickly to form Pd black.
The observed difference in reactivity of the oxazo-
line ligands in the ortho-palladation reactions points
to the importance of steric hindrances in the ligands.
Failure of direct cyclopalladation of 2-(2-naph-
tyl)oxazoline with the 4,5-non-substituted heterocycle
may serve as reliable evidence of this effect [17]. Ex-
amples of this phenomena have been reported for
other ligands as well [18].
The failure of using Na2PdCl4 with AcONa for cy-
clopalladation was not surprising since this method
provided only a trace amount (B5%) of the corre-
Here we report our results on the preparation of
cyclopalladated derivatives of sterically non-hindered
2-phenyl-2-oxazoline.
Scheme 1.

88
I.P. Smoliako6a et al. / Journal of Organometallic Chemistry 603 (2000) 86–97
Scheme 2.
Scheme 3.
sponding cyclopalladated compound in the reaction
with more sterically hindered 4,4-dimethyl-2-(2-
naphtyl)-2-oxazoline and no cyclopalladated product at
all with a related non-substituted analog [17]. Despite
one precedent of ortho-palladation of a 4-monosubsti-
tuted on the heterocycle 1,4-bis(oxazoline) ligand under
similar conditions (Na2PdCl4, MeOH–H2O), reliable
proof of the proposed cyclopalladated structure has not
been provided [16].
addition of AcONa to the mixture of 1 and Pd(OAc)2
and lowering the reaction temperature (50°C for 1 h
and then r.t. for 9 days) increased the yield of 3a to
63% (Scheme 2, method B). Lowering the temperature
without adding AcONa did not improve the yield
(24%). Probably, the introduction of AcONa assisted
the CꢁH bond activation and increased to some extent,
the polarity of the reaction milieu that, in turn, facili-
tated the cyclopalladation.
One of the most efficient cyclopalladation methods is
the use of highly electrophilic Pd(OAc)2 in AcOH. In
particular, this approach has been utilized successfully
for the synthesis of the known cyclopalladated deriva-
tives of oxazolines [10–13]. Application of this method
to the ortho-palladation of 1 showed that the reaction
was very sensitive to the quality of the reagents and
AcOH, as well as to the reaction time and temperature;
the yield of the desirable cyclopalladated complex (3a)
varied from 12 to 44% (cf. Ref. [6]). The best yield of
dimer 3a was achieved when 2-phenyl-2-oxazoline (1)
reacted with Pd(OAc)2 in AcOH at 95°C for 2 h and
then at r.t. for 60 h (Scheme 2, method A). The
subsequent anion methathesis using LiCl in acetone led
to the quantitative formation of its m-chloro-bridged
analog (3b).
Next we examined a number of other methods of
intramolecular CꢁH bond activation, which have been
used successfully for the preparation of cyclopalladated
compounds inaccessible by more common means. One
method is based on cyclopalladated ligand exchange
[24–26]. This methodology worked very well in the case
of electron-deficient ligands [27], for the formation of
non-optimal six-membered palladacycles [28], and acti-
vation of (sp3) CꢁH bonds [24,26]. Using this approach,
we obtained dimeric ortho-palladated complex 3b by
reacting ligand 1 with di-m-chlorobis-[2-[(dimethyl-
amino)methyl]phenyl-C,N]dipalladium(II) (4) at 50°C
in a CHCl3–AcOH mixture in an excellent yield of 90%
(Scheme 3).
Previously, it has been suggested that AcOH is a
necessary component in the reaction milieu [24,25]. Our
data support this hypothesis. Thus, the ligand exchange
conducted in toluene at the same temperature resulted
in the quantitative formation of compound 5 (Scheme
It is well known that the use of the weak base
AcONa along with M2Pd(Hal)4 (M=Li, K, Na) pro-
motes cyclopalladation [19,21–23]. We found that the

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89
Scheme 4.
3). Such adducts have been recognized as the first
intermediates in cyclopalladated ligand exchange reac-
tions [25,26]. Another necessary condition of a ligand
exchange is the thermal activation of this process.
When complex 4 reacted with oxazoline 1 at r.t., only
coordination complex 2 was formed, probably, due to
protonolysis of the PdꢁC bond of dimer 4 with subse-
quent displacement of the tertiary benzylamine by the
oxazoline ligand (Scheme 3). Our attempts to convert
coordination complex 2 to cyclopalladated dimer 3b by
heating it in an AcOH–CHCl3 mixture (as well as in
MeOH, cf. Ref. [28]) failed4. This may serve as an
indirect indication of the intramolecular activation of a
new CꢁH bond with the assistance of the CꢁPd bond in
the starting complex; bis(ligand) coordination com-
plexes (related to 2) may not be intermediates in the
cyclopalladated ligand exchange reaction (in contrast to
the earlier proposed mechanism [26]).
Another possibility for the conversion of dichloro
bis(ligand) coordination complexes to cyclopalladated
analogs is their consecutive treatment with AgBF4 and
n-Bu4NCl [29]. The main driving forces of this reaction
are the enhanced electrophilicity of the palladium(II)
center (which has acquired the positive charge) and the
appearance of the coordination vacancy required for
CꢁH bond activation. Unfortunately, after treatment of
complex 4 with AgBF4 in ethyl acetate with the subse-
quent introduction of n-Bu4NCl, the starting com-
pound 4 was recovered in 12% yield with no traces of
cyclopalladated derivative 3b5.
ful internal base (similarly to that operating in ligand
exchange reactions). To test this approach for cyclopal-
ladation of oxazoline (1), we first prepared acetylaceto-
nate derivative 6 by reaction of 3b with 2,4-pentadione
and KOH in MeOH (Scheme 4) [36,37]. Unfortunately,
our attempts to synthesize the same complex 6 using
the reaction of Pd(acac)2 with 1 failed.
For subsequent structural studies, cyclopalladated
dimer 3b was quantitatively converted into its mononu-
clear phosphane adduct 7 by reaction with PPh3
(Scheme 4).
2.2. Spectral characterization of complexes
The proposed structures of the complexes prepared
(2, 3a,b, 5–7) were supported by IR, 1H- and 13C-NMR
1
spectroscopy. Signal assignment in the routine H- and
13C-NMR spectra was done based on the analysis of
COSY, DEPT, and HETCOR data.
The presence of the PdꢁC bond in the cyclopalla-
dated compounds was confirmed by both IR and NMR
spectroscopy. In the IR spectra of cyclopalladated com-
pounds 3a,b and 7, the region of out-of-plane bending
vibrations of aromatic CꢁH bonds contained only one
strong absorption band at 725–729 cm−1 as was ex-
pected for disubstituted benzene rings [38]. The IR
spectra of ligand 1 and coordination complex 2 had two
characteristic bands for monosubstituded arenes: 695–
697 and 780 cm−1. These frequencies are similar to
those found for related cyclopalladated compounds B
(725–730 cm−1), the corresponding ligands, and coor-
Bis(b-diketonate)palladium(II) complexes, e.g. Pd(a-
cac)2, can also serve as palladation agents [30–35]. This
method is based on the isomerization of a b-diketonate
ligand from the O,O%-chelated state to the monodentate
g-C-bonded one [31–35]. As was demonstrated in the
case of cyclopalladation of primary benzylamine [30],
the g-C-bonded b-diketonate ligand served as a power-
dination compounds (690–695 and 745–750 cm−1
)
[10]. IR spectroscopy cannot be used for supporting the
structures of oxazoline adduct 5 and phosphane com-
plex 7 since their molecules contain both mono- and
disubstituted phenyl rings.
The 1H-NMR spectra afforded more reliable evi-
dence of ortho-palladated structure of dimer 3a and
mononuclear complexes 6 and 76. Thus, for these com-
pounds, the total integral intensity of aromatic protons
corresponded to the disubstituted aryl ring. In the
spectra of dimer 3a, signals of aromatic protons con-
sisted of a group of unresolved multiplets located in a
narrow interval of ca. 0.2 ppm that is typical for other
4 Complex 2 (100 mg, 0.21 mmol) was refluxed in 3 ml of a 1:1
mixture of AcOH–CHCl3 for 8 h. After solvent evaporation and
recrystallization, 86 mg (86%) of 2 was recovered. Another reaction
was carried out in CH3OH under the same conditions; 91% of
compound 2 was recovered. In both reactions after solvent evapora-
tion, the residues were analyzed by 1H-NMR spectroscopy. No trace
of desired complex 3b was detected.
5 The reaction was carried out using n-Bu4NCl under the condi-
tions reported for the preparation of di-m-iodo-bis{[(2-amino-
methyl)phenyl]palladium(II)} in Ref. [29].
6 NMR spectra of m-chloro dimer 3b could not be measured owing
its extremely low solubility in common organic solvents.

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at 70.1, 3.56, and 4.32 ppm in 13C- and 1H-NMR
spectra were assigned to the OCH2 group7.
The H-NMR spectra of phosphane adduct 7 con-
ortho-palladated 2-aryl-2-oxazolines (l 6.98–7.10 ppm
[12]). These signals were partly resolved in the spectra
of acetylacetonate derivative 6. As was found for re-
lated complexes [39], the doublet of aromatic H(6)
appeared at lower field compared to other aromatic
hydrogens because of the deshielding effect of one of
the diketonate carbonyl groups.
1
tained three well-separated signals of ortho-, meta-, and
para-hydrogens of PPh3 at l 7.73, 7.36, and 7.43 ppm,
respectively. The multiplets of ortho- and meta-hydro-
gens contained spin–spin coupling with the P nuclei
(3JPH=11.7 and 4JPH=2 Hz, respectively). The
downfield shift of the signal of the PPh3 ortho-hydro-
gens might be explained by their close proximity to the
palladium anisotropy domain [53,54]. The 13C-NMR
spectrum of adduct 7 exhibited six doublets (JCP) of
four carbon atoms of the Pꢁphenyl group [55] and C-5
and C-6 of the phenylene ring. Interestingly enough, the
PdC(1) signal appeared as a singlet.
In the 1H-NMR spectrum of 7, the multiplet of
aromatic H(6) at l 6.43 ppm contained splitting by the
P atom (4JPH-6=4.7 Hz). This is another important
proof of the ortho-palladated structure of 7 (and, there-
fore, parent compounds 3a,b as well) and unambiguous
evidence of the trans(N,P)-geometry of the mononu-
clear complex [18a,40]. The H(6) signal was shifted
upfield due to the shielding effect of the Pꢁaryl rings.
This phenomenon has been observed previously in
arylphosphane adducts of some cyclopalladated com-
pounds [18a–d,41,42].
In accordance with the ortho-palladated structure of
complexes 3a, 6, and 7, their 13C-NMR spectra con-
tained the signal of the quaternary carbon atom (C(1))
directly bonded to the palladium atom: l 147.6, 150.1,
and 151.8 ppm, respectively. These values are within
the range of chemical shifts (l 141–160 ppm) reported
for other ortho-palladated complexes [43–49].
1
The H- and 13C-NMR spectra of compound 6 con-
tained signals of two non-equivalent CH3 groups (l
1.99, 2.08, and 27.5, 27.8 ppm, respectively) within the
range of chemical shifts reported for other acetylaceto-
nate derivatives of cyclopalladated complexes (l 1.8–
2.2 ppm [35,39] and 27–29 ppm [39,43]). In the IR
spectrum of 6, three characteristic bands at 1576, 1563,
and 1515 cm−1 resulted from the coupled symmetric
CꢀO stretching vibrations, out-of-plane CꢁH bending
vibrations, and asymmetric stretches of the C···C···C
fragment [35].
Coordination of the oxazoline ring through the imine
nitrogen atom in complexes 2, 3a,b, 6, and 7 was
evident enough from a low-frequency shift of the strong
band of CꢀN stretching vibration. This band moved
from 1649 cm−1 in the IR spectrum of ligand 1 down
to 1630–1638 cm−1 in the spectra of dimers 3a,b. The
coordination shift was somewhat smaller (DwCꢀN= −
7 cm−1) in the case of phosphane adduct 7 due to the
large trans-influence of the phosphorus atom weaken-
ing this bond. The rather weak N“Pd coordination of
the oxazoline in complex 2 (DwCꢀN= −6 cm−1) might
be caused by steric effects.
The structure of m-acetato complex 3a was supported
by IR and NMR spectroscopy data. The IR spectrum
showed two strong bands at 1562 and 1401 cm−1
corresponding to asymmetric and symmetric stretching
vibrations of the OꢀCꢁO group, respectively (cf. 1560–
1570 and 1400–1420 cm−1 for related compounds
1
[10,12,50,51]). The H-NMR spectrum contained only
one singlet of the m-AcO groups at l 2.16 ppm (cf. l
2.1–2.3 ppm for related dimers [10,12]). This suggests
that dimer 3a exists in CDCl3 solution as a single
anti-isomer with the usual open-book-like structure.
This conclusion was supported by the presence of only
one set of the 13C-NMR signals [11,14]. A strong
predominance of this symmetric ab–gh geometry
[10,51] and the dimer’s existence in CDCl3 solution as
the single isomer [12,52] were found previously for
other cyclopalladated oxazoline derivatives [10,12] and
related dimeric complexes of aryl substituted heterocy-
cles [51,52].
As a consequence of the open-book structure of
dimer 3a, each of two methylene protons of the oxazo-
line ring are non-equivalent and gave three unresolved
multiplets (l 2.84, 3.56, and 4.32 ppm) with a relative
integration ratio of 1:2:1. According to the HETCOR
spectrum of 3a, two protons giving multiplets at l 2.84
and 3.56 ppm are attached to the carbon providing the
signal at l 49.5 ppm; two protons attached to the other
carbon of the heterocycle (l 70.1 ppm) gave rise to two
multiplets at 3.56 and 4.32. Based on the higher elec-
tronegativity of oxygen compared to nitrogen, signals
Comparative analysis of the 1H-NMR spectra of
cyclopalladated compounds 3a,b, 6, and 7 with those of
coordination complex 2 and adduct 5 revealed addi-
tional spectral differences of these two groups of com-
plexes. The signals of oxazoline aromatic hydrogens
were presented in the spectra of complexes 2 and 5 by
two multiplets at l 8.98–8.94 and 7.55–7.45 ppm with
a relative integration intensity ratio of 2:3, respectively.
Based on the COSY spectra of 2 and 5, the signals were
assigned to ortho- and meta-, and para-protons of the
aromatic ring, respectively. The observed downfield
7 In Ref. [12], 13C-NMR signals of OCH2 and NCMe2 groups for
the related compound di-m-acetatobis-[2-(4%,4%-dimethyl-2-oxa-
zolinyl)phenyl-C,N]dipalladium (Fig. 1, structure B, R1=Me, R2=
H) were assigned incorrectly. We synthesized this compound, and its
DEPT spectrum indicated that the higher field signal at 64.8 ppm
belonged to the quaternary carbon of the NCMe2 group, whereas the
lower field signal at 81.8 ppm resulted from the resonance of the
secondary carbon of the OCH2 fragment.

I.P. Smoliako6a et al. / Journal of Organometallic Chemistry 603 (2000) 86–97
91
shift of the ortho-proton signals may be indicative of
the orthogonal orientation of the oxazoline ring in
respect to the palladium coordination plane [48,51].
Magnetic non-equivalence of the NCH2 protons in
complex 5 due to the asymmetric environment of the
N-donor atom may serve as additional evidence in
favor of the proposed configuration. The orthogonal
orientation of the oxazoline ligand led to the preferable
position of the ortho-protons of ligand 1 in close prox-
imity to the anisotropy domain of the palladium center
in axial position (cf. [48,51]). A large downfield shift of
the ortho-H signal observed in the spectra of complexes
2 and 5 compared to free ligand 1 (Dl=1.08 and 1.03
ppm, respectively) suggests some CꢁH bond interaction
with the metal center which is considered now as a
necessary stage in the CꢁH bond activation processes
[52].
2.3. X-ray structure study of coordination complex 2
and phosphane adduct 7
The most unambiguous confirmation of h2-C,N-
bonding of 2-phenyl-2-oxazoline ligand in phosphane
adduct 7 and its monodentate h1-N-coordination in the
case of complex 2 was obtained from their X-ray
diffraction study.
2.3.1. Coordination complex 2
The crystals of coordination complex 2 suitable for
the X-ray diffraction study were grown from a
dichloromethane–hexane mixture. The molecular struc-
ture of compound 2 is presented in Fig. 2; selected
bond lengths and angles are given in Table 1.
Despite a number of palladium(II) coordination com-
plexes with bi- [1c,56,57] and tridentate [58] oxazoline
ligands structurally characterized, the X-ray study of
only one palladium(II) complex bearing a monodentate
oxazoline ligand [PdCl2 complex with 4,4-dimethyl-2-
(2-naphthyl)oxazoline (8)] has been reported thus far
[17]. The data for compound 8 were used here for
comparison purposes.
Both complexes 2 and 8 have a centrosymmetric
structure with strictly planar coordination environment
of the palladium center. The deviation from the square
geometry is also small, with the NꢁPdꢁCl angles of
90.87–91.1°8.Two monodentate N-bonded oxazoline
ligands are trans-disposed with nearly identical lengths
of PdꢁN and PdꢁCl bonds equal to 2.007–2.036 and
,
2.300–2.303 A, respectively. The heterocycle in both
complexes may be described as nearly planar with the
ring having a negligible twisting extent: the average
endo-cyclic torsion angle is equal to 2.9–2.5°, and
maximal displacement from the mean oxazoline plane
(observed for the carbon of the OCH2 group) is equal
Fig. 2. Molecular structure and numbering scheme of the coordina-
tion complex 2. Displacement ellipsoids are shown 50% probability
level.
Table 1
,
to 0.026–0.022 A.
,
Selected bond lengths (A) and angles (°) for coordination complex 2
In full accordance with our predictions from the
1H-NMR data (see Section 2.2), in both complexes 2
and 8 the oxazoline ligands are oriented nearly orthog-
onal to the mean coordination plane, with interplanar
angles taken for oxazoline ring equal to 101.9 and
93.7°, respectively. The difference between the two re-
lated complexes becomes more pronounced when the
tilting of the azomethine CꢀN bond with respect to the
mean coordination plane is considered: the torsion
angle CꢀNꢁPdꢁCl equals 107.9 and 97.9° for complexes
2 and 8, respectively.
Bond lengths
PdꢁN(1A)
PdꢁN(1)
PdꢁCl(1)
PdꢁCl(1A)
O(1)ꢁC(9)
2.0072(14)
2.0072(14)
2.300(2)
2.300(2)
1.344(2)
O(1)ꢁC(8)
N(1)ꢁC(9)
N(1)ꢁC(7)
C(1)ꢁC(9)
C(7)ꢁC(8)
1.459(2)
1.271(2)
1.475(2)
1.468(2)
1.524(2)
Bond angles
N(1A)ꢁPdꢁN(1)
N(1A)ꢁPdꢁCl(1)
N(1)ꢁPdꢁCl(1)
180.0
89.13(5)
90.87(5)
C(9)ꢁN(1)ꢁPd
C(7)ꢁN(1)ꢁPd
130.02(11)
119.89(10)
C(2)ꢁC(1)ꢁC(9) 121.17(14)
C(6)ꢁC(1)ꢁC(9) 118.82(14)
N(1)ꢁC(7)ꢁC(8) 102.95(13)
O(1)ꢁC(8)ꢁC(7) 104.37(13)
N(1)ꢁC(9)ꢁO(1) 116.10(14)
N(1)ꢁC(9)ꢁC(1) 127.98(13)
O(1)ꢁC(9)ꢁC(1) 115.92(13)
N(1A)ꢁPdꢁCl(1A) 90.87(5)
N(1)ꢁPdꢁCl(1A)
Cl(1)ꢁPdꢁCl(1A)
C(9)ꢁO(1)ꢁC(8)
C(9)ꢁN(1)ꢁC(7)
89.13(5)
180.0
107.08(12)
109.30(13)
Two non-symmetric organic ligands are anti-ar-
ranged with respect to the mean coordination plane
8 Here and below, the first and second values are parameters of
complexes 2 and 8, respectively.

92
I.P. Smoliako6a et al. / Journal of Organometallic Chemistry 603 (2000) 86–97
zoline ring, with interplanar angles of 29.6–27.6°. Their
orientation to the mean coordination plane remains
close to the orthogonal, with interplanar angles of
105.4–93°.
The most interesting structural feature of the coordi-
nation complex 2 is a rather short contact of one of the
ortho-hydrogens of the 2-phenyl substituent with the
2
,
palladium atom with a H ···Pd distance of 2.679 A. The
similar contact between the C1H of naphthalene ring
,
and metal at the distance of 2.734 A was found also for
the related complex 8. These distances are markedly less
than the sum of van der Waals radii of Pd and H atoms
,
(3.1 A [60]) and may be considered as evidence of some
kind of secondary interaction [54c,h]. This structural
1
peculiarity is in full accordance with the H-NMR data
for complex 2 (see Section 2.2) which point to the
retaining of the same configuration in solution.
Such interactions are often considered as a step pre-
ceding the CꢁH bond activation [54c,h] Thus, in the
case of coordination complex 2, a close above-plane
approach of the ortho-CꢁH bond to the metal center
may be recognized as the optimal orientation for subse-
quent ortho-palladation of 2-phenyl-2-oxazoline.
Fig. 3. Molecular structure and numbering scheme of the phosphine
adduct 7. Displacement ellipsoids are shown 50% probability level.
Hydrogen atoms and solvent CH3Cl2 molecule are omitted for clarity.
Table 2
,
Selected bond lengths (A) and angles (°) for phosphane adduct
7·CH2Cl2
2.3.2. X-ray structure in6estigation of phosphane
adduct 7
Bond lengths
Pd(1)ꢁC(1)
Pd(1)ꢁN(1)
Pd(1)ꢁP(1)
Pd(1)ꢁCl(1)
P(1)ꢁC(11)
P(1)ꢁC(21)
P(1)ꢁC(31)
O(1)ꢁC(7)
O(1)ꢁC(9)
N(1)ꢁC(7)
2.030(4)
2.062(3)
2.256(1)
2.368(2)
1.818(4)
1.827(4)
1.832(4)
1.335(5)
1.457(6)
1.266(6)
N(1)ꢁC(8)
C(1)ꢁC(2)
C(1)ꢁC(6)
C(2)ꢁC(3)
C(3)ꢁC(4)
C(4)ꢁC(5)
C(5)ꢁC(6)
C(6)ꢁC(7)
C(8)ꢁC(9)
1.471(6)
1.395(6)
1.414(5)
1.378(6)
1.389(7)
1.380(7)
1.387(6)
1.440(6)
1.530(7)
Suitable crystals of this complex were grown from a
dichloromethane–hexane mixture in the presence of
trace amounts of ether. The molecular structure of the
complex and its packing in the crystal are presented in
Fig. 3 and 4; selected bond lengths and angles are given
in Table 2. The crystal contains wide channels passing
along the b-axis, which are occupied by disordered
molecules of dichloromethane.
Three cyclopalladated derivatives of aryl substituted
oxazolines have been previously characterized struc-
turally: the m-acetato dimer containing a palladacycle of
C,N-type, C1 (Fig. 1, complex type C, R1=Me, R2=
R3=H) [13] and two related cyclopalladated deriva-
tives of bis(oxazoline)benzenes of N,C,N-pincher type,
A1 (Fig. 1, complex type A, Hal=Cl, R=i-Pr) [15] and
A2 (Fig. 1, complex type A, Hal=I, R=CMe2Ph) [6b].
Unfortunately, only two X-ray structural data sets of
compounds A1 and C1 are available from the CCDC;
they are used here for comparison purposes.
Bond angles
C(1)ꢁPd(1)ꢁN(1)
C(1)ꢁPd(1)ꢁP(1)
N(1)ꢁPd(1)ꢁP(1)
C(1)ꢁPd(1)ꢁCl(1) 169.0(1)
N(1)ꢁPd(1)ꢁCl(1)
P(1)ꢁPd(1)ꢁCl(1)
C(11)ꢁP(1)ꢁC(21) 107.4(2)
C(11)ꢁP(1)ꢁC(31) 101.0(2)
C(21)ꢁP(1)ꢁC(31) 103.6(2)
C(11)ꢁP(1)ꢁPd(1) 116.1(1)
C(21)ꢁP(1)ꢁPd(1) 110.5(1)
C(31)ꢁP(1)ꢁPd(1) 117.0(1)
C(7)ꢁO(1)ꢁC(9)
C(7)ꢁN(1)ꢁC(8)
C(7)ꢁN(1)ꢁPd(1)
C(8)ꢁN(1)ꢁPd(1)
C(2)ꢁC(1)ꢁC(6)
C(2)ꢁC(1)ꢁPd(1)
C(6)ꢁC(1)ꢁPd(1)
80.7(2)
94.8(1)
174.1(1)
C(3)ꢁC(2)ꢁC(1)
C(2)ꢁC(3)ꢁC(4)
C(5)ꢁC(4)ꢁC(3)
C(4)ꢁC(5)ꢁC(6)
C(5)ꢁC(6)ꢁC(1)
C(5)ꢁC(6)ꢁC(7)
C(1)ꢁC(6)ꢁC(7)
N(1)ꢁC(7)ꢁO(1)
N(1)ꢁC(7)ꢁC(6)
O(1)ꢁC(7)ꢁC(6)
N(1)ꢁC(8)ꢁC(9)
O(1)ꢁC(9)ꢁC(8)
C(12)ꢁC(11)ꢁP(1)
C(16)ꢁC(11)ꢁP(1)
C(22)ꢁC(21)ꢁP(1)
C(26)ꢁC(21)ꢁP(1)
C(36)ꢁC(31)ꢁP(1)
C(32)ꢁC(31)ꢁP(1)
122.0(4)
121.9(4)
118.3(4)
119.2(4)
124.0(4)
122.2(4)
113.8(4)
117.4(4)
119.9(4)
122.6(4)
101.5(4)
105.8(4)
120.9(3)
120.9(3)
116.6(3)
124.5(3)
122.5(3)
118.3(3)
88.6(1)
96.07(4)
The unit cell contains four molecules of the mononu-
105.6(3)
109.7(4)
113.4(3)
136.9(3)
114.5(4)
133.5(3)
112.0(3)
clear complex
7 and four solvate molecules of
dichloromethane (Fig. 4). The latter molecules are dis-
ordered and are inserted into the cages in the unit cell
without any bonding with the complex atoms. The
ortho-palladated structure of this phosphane adduct
(and, therefore, that of the starting dimers 3a,b) is quite
evident. In accordance with the spectral data (see
above, Section 2.2), complex 7 has trans(P,N) geo-
metry. The PdꢁC and PdꢁN bond lengths equal
with their 2-aryl substituents disposed above and below
it, resulting in the creation of a prochiral structure [59].
The 2-aryl ring is markedly twisted regarding the oxa-
,
2.030(4) and 2.062(3) A, respectively, and are longer to

I.P. Smoliako6a et al. / Journal of Organometallic Chemistry 603 (2000) 86–97
93
some extent compared to the m-AcO-dimer C1 (1.968
3. Conclusions
,
and 2.030 A, respectively), probably, due to the cis-
Direct ortho-palladation of a 2-phenyl-2-oxazoline
ligand non-substituted on the heterocyclic ring was
achieved in a moderate yield of 63% through its reac-
tion with Pd(OAc)2 in the presence of AcONa. A high
efficiency of the cyclopalladated ligand exchange
method was demonstrated: the target m-chloro dimer
was prepared in a high yield of 90% by the reaction of
the oxazoline ligand with ortho-palladated complex of
N,N-dimethylbenzylamine in a AcOH–CHCl3 mixture
at 50°C. The complexes obtained were characterized by
and trans-influence of phosphane instead of the m-ac-
etato ligand.
The palladium atom in complex 7 has a nearly
square-planar coordination environment with a rather
slight tetrahedral distortion. The dihedral angle be-
tween the planes {C1Pd1N1} and {P1Pd1Cl1} is equal
to 4.3° and the displacement of the main atoms from
the mean coordination plane does not exceed 0.064
,
A.
The palladacycle conformation in the phosphane
1
IR, H- and 13C-NMR data. The structures of coordi-
adduct 7 may be described as nearly planar, with the
averaged absolute value of intrachelate torsion angle
ca. 3.4°. It shows good consistency with the corre-
sponding values for palladacycles in complexes A1
and C1 (1.3 and 1.7°, respectively) and may be recog-
nized as their general property. This characteristic is
in drastic contrast with the pronounced twisting of
the benzylamine-derived palladacycles where the range
of average intrachelate torsion angles is expanded up
to the 32° in the case of adducts with the sterically
crowded diphosphine ligands [61].
nation complex 2 and cyclopalladated mononuclear
complex 7 were unambiguously established by their
X-ray diffraction study.
Currently we are working on synthesis and applica-
tions of chiral oxazoline-based cyclopalladated
complexes.
4. Experimental
4.1. General
The oxazoline heterocycle in 7 may be described as
ideally planar with the displacement of its main
atoms from the mean plane {N1C7O1C9C8} not ex-
Routine 1H- and 13C-NMR (500 and 125 MHz,
respectively), DEPT, COSY, and HETCOR spectra
were recorded in CDCl3 using TMS as an internal
standard on an Avance 500 Bruker spectrometer. Spin–
spin coupling constants, J, are given in Hz. IR spectra
were recorded on an ATI Mattson Genesis Series FTIR
as Nujol mulls. Analytical TLC was performed on
Merck precoated 0.2 mm plates of silica gel 60 F254
Melting points were measured on a Laboratory Device
Mel-Temp apparatus and were not corrected.
All chemicals, including complex 4, were purchased
from Aldrich Chem. Co. Pd(OAc)2 was purified by
refluxing in benzene for 5 min, filtering the solution,
and removing the solvent. AcOH was refluxed over
KMnO4 for 3 h and then distilled. Other solvents were
distilled over CaH2 prior to use.
,
ceeding 0.0032 A (found for the nitrogen atom). The
same holds true for two other oxazoline-derived
ortho-palladated complexes, A1 and C1 (0.0025 and
,
0.0041 A, respectively).
As may be expected for such a strongly conjugated
tricyclic system, all three rings in molecule 7 are
nearly coplanar, with the interplanar angles between
the phenylene or oxazoline ring on one hand, and the
palladacycle on the other, being equal to 3.4 and
3.8°, respectively. The same parameters for the related
complexes A1 and C1 are decreased down to values of
1.5–2.0 and 2.4–2.2°, respectively. It is noteworthy
that only in the case of the A2 complex which bears a
very bulky CMe2Ph group, a more pronounced twist-
ing of two oxazoline rings out of the plane of the
aromatic ring (6.8 and 8.8°, respectively) was reported
[6b].
.
4.2. Dichlorobis-(2-phenyl-2-oxazoline)palladium(II) (2)
1
In accordance with the H-NMR data for the phos-
4.2.1. Method A
phane adduct 7 (where the signal of phosphane ortho-
hydrogens is shifted downfield to l 7.75 ppm), the
distance between one of the ortho-Ph protons and the
A solution of Na2PdCl4 (100 mg, 0.34 mmol) in abs.
MeOH (3 ml) was added to 2-phenyl-2-oxazoline (110
mg, 0.75 mmol). A yellow precipitate was formed im-
mediately. After stirring the mixture for 24 h at r.t., the
yellow solid was filtered out, washed with MeOH, and
recrystallized from CHCl3–hexane. Yield, 132 mg
(82%). Rf 0.57 (1:9 ethyl acetate–toluene); m.p. (dec.)
226–227°C; IR (w, cm−1): 1643 s (CꢀN); 780 s and 697
22
1
,
palladium atom (C H···Pd ) is decreased to 2.93 A,
which is smaller than the sum of van der Waals radii
,
of these atoms (3.1 A) [62]. In the cases of other
arylphosphane adducts of ortho-palladated complexes,
the similar H···Pd distances were found to be shorter
1
,
(2.66–2.78 A) with the corresponding larger
m (arom. CH); H-NMR (l, ppm): 4.33 (t, 2H, J=9,
NCH2), 4.60 (t, J=9, OCH2), 7.56 (t, 2H, 3J=7.7,
downfield shifts of the phosphane ortho-H signal (l
3
8.38–8.47 ppm) [53].
meta-CH), 7.63 (t, 1H, J=7.7, para-CH), 8.98 (d, 2H,

94
I.P. Smoliako6a et al. / Journal of Organometallic Chemistry 603 (2000) 86–97
3J=7.7, ortho-CH); 13C-NMR (l, ppm): 55.5 (NCH2),
68.1 (OCH2), 124.9 (arom. quat. C), 128.5, 130.1, 133.1
(arom. CH), 167.9 (OCN). Anal. Calc. For
C18H18N2O2Cl2Pd: C, 45.84; H, 3.85; N, 5.94. Found:
C, 45.67; H, 3.75; N, 5.71%.
SiO2 (H=2 cm). After solvent removal, the yellow
solid was recrystallized from CHCl3–hexane. Yield,
58.3 mg (63%).
4.4. Di-v-chlorobis-[2-(2-oxazolinyl)phenyl-
C,N]dipalladium(II) (3b)
4.2.2. Method B
2-Phenyl-2-oxazoline (30.9 mg, 0.210 mmol) was
added to a solution of complex 4 (52.5 mg, 0.095 mmol)
in 1.5 ml AcOH and 1.5 ml CHCl3. The mixture was
stirred at r.t. for 141 h. The yellow precipitate formed
was filtered out, washed with AcOH and hexane, and
recrystallized from CHCl3–hexane. Yield, 15 mg (33%).
4.4.1. Method A
LiCl (9.3 mg, 2.2 mmol) was added to a solution of
3a (62.3 mg, 1 mmol) in abs. acetone (5 ml). After
stirring for 60 h at r.t., the pale-yellow solid formed
was washed with H2O, MeOH, and Et2O. The com-
pound was insoluble in a variety of solvents, so no
purification was attempted. Yield, 57.4 mg (99%). m.p.
(dec.) 208°C; IR (w, cm−1): 1638 s (CꢀN); 725 s
(arom. CH); Anal. Calc. for C18H16N2O2Cl2Pd2: C,
37.53; H, 2.80; N, 4.86. Found: C, 36.84; H, 2.89; N,
4.60%.
4.3. Di-v-acetatobis-[2-(2-oxazolinyl)phenyl-
C,N]dipalladium(II) (3a)
4.3.1. Method A
AcOH (1 ml) was added to Pd(OAc)2 (224 mg, 1
mmol) and the mixture was heated at 95°C for a few
minutes. Then 2-phenyl-2-oxazoline (0.13 ml, 1 mmol)
was added. After stirring at 95°C for 2 h and then at
r.t. for 60 h, the mixture was diluted with H2O and
extracted with CHCl3 (3×10 ml). Organic layers were
combined, washed with aqueous saturated solution of
NaHCO3, and run through a layer of SiO2 (H=1 cm).
After solvent removal, the yellow solid was recrystal-
lized from CHCl3–hexane. Yield, 137 mg (44%). Rf
0.469 (1:9 ethyl acetate–toluene); m.p. (dec) 218–
220°C; IR (w, cm−1): 1630 s (CꢀN), 727 s (arom. CH),
4.4.2. Method B
2-Phenyl-2-oxazoline (28.3 mg, 0.192 mmol) was
added to a solution of 4 (53.7 mg, 0.097 mmol) in 1.5
ml AcOH and 1.5 ml CHCl3. The mixture was stirred at
50°C for 37 h and then at r.t. for 48 h. The yellow
precipitate was filtered off, washed with AcOH and
H2O. The solid was insoluble in a variety of solvents, so
no recrystallization was attempted. Yield of the crude
product was 48.9 mg (90%).
1
1562 s and 1401 s (COO); H-NMR (l, ppm): 2.16 (s,
4.5. Chloro[N,N-dimethylbenzylamino]-
(2-phenyl-2-oxazoline)palladium(II) (5)
3H, CH3), 2.84 (m, 1H, NCH), 3.56 (m, 2H, NCH and
OCH), 4.31 (m, 1H, OCH), 6.98–7.18 (m, 4H, arom.
CH); 13C-NMR (l, ppm): 24.5 (CH3), 49.7 (NCH2),
70.3 (OCH2), 123.9, 125.6, 130.5 and 131.6 (arom. CH),
131.3 (arom. C(2)), 147.6 (PdC(1)), 174.6 (OCN), 181.6
(COO); Anal. Calc. for C22H22N2O6Pd2: C, 42.39; H,
3.56; N, 4.49. Found: C, 42.29, H 3.57, N 4.51%.
2-Phenyl-2-oxazoline (265 mg, 1.8 mmol) was added
to a solution of 4 (50.3 mg, 0.091 mmol) in toluene (3
ml). The mixture was stirred at 50°C for 10 h. The pale
yellow precipitate was filtered off, washed with hexane,
and recrystallized from CHCl3–hexane. Yield, 26.8 mg
(93%). Rf 0.43 (1:9 ethyl acetate–toluene); m.p. (dec.)
4.3.2. Method B
164°C; IR (w, cm−1): 1649 s (CꢀN); H-NMR (l, ppm):
1
A mixture of Pd(OAc)2 (73.6 mg, 0.328 mmol) and
AcONa (27.0 mg, 0.329 mmol) was partially dissolved
in AcOH (1 ml). 2-Phenyl-2-oxazoline (57.6 mg, 0.357
mmol) was dissolved in AcOH (1 ml). The two solu-
tions were combined and allowed to stir at r.t.
overnight. The reaction mixture was stirred at 50°C for
1 h and then at r.t. for 9 days. The yellow precipitate
started forming after 3 days. The mixture was diluted
with H2O and extracted with CHCl3 (3×10 ml). Or-
ganic layers were combined, washed with aqueous satu-
rated solution of NaHCO3, and run through a layer of
2.95, 2.98 (two s, 6H, N(CH3)2), 3.80, 4.10 (two d,
2J=14, PhCH2), 4.20 (m, 1H, NCH), 4.60 (m, 3H,
3
OCH2CHN), 6.44 (d, 1H, J=7.6, H(6) of C6H4), 6.78
(m, 1H, H(5) of C6H4), 6.94 (m, 2H, H(3) and H(4) of
3
C6H4), 7.43 (br. t, 2H, J:8, meta-H of C6H5), 7.51
3
(br. t, 1H, J:8, para-H of C6H4), 8.93 (br. d, 1H,
3J:8, ortho-H of C6H5); 13C-NMR (l, ppm): 52.5 and
52.9 (N(CH3)2), 56.7 (NCH2), 68.4 (OCH2), 74.0
(NCH2Ph), 121.6 (HC-3 of C6H4), 124.4 (HC(4) of
C6H4), 125.2 (quat. C of C6H5), 125.4 (HC(5) of C6H4),
128.2 (meta-CH of C6H5), 130.0 (ortho-CH of C6H5),
131.4 (HC(6) of C6H4), 132.8 (para-CH of C6H5), 146.1
and 147.5 (PdC(1) and C(2) of C6H4), 166.8 (OCN);
Anal. Calc. for C18H21N2OClPd: C, 51.07; H, 5.01; N,
6.62. Found: C, 50.59; H, 4.96; N, 6.53%.
9 The compound streaks on a TLC plate. Rf value is given for the
top of the streak.

I.P. Smoliako6a et al. / Journal of Organometallic Chemistry 603 (2000) 86–97
95
4.6. [2-(2-Oxazolinyl)phenyl-C,N](acetylacetonato-
O,O%)palladium(II) (6)
mmol) in MeOH (1 ml) were added to a suspension of
3b (50 mg, 0.081 mmol) in MeOH (6 ml). The mixture
was stirred at r.t. for 3 h. After filtration, MeOH was
removed from the solution and the crude complex was
recrystallized from MeOH–H2O. Yield, 23 mg (38%).
Rf 0.56 (1:9 ethyl acetate–toluene); m.p. (dec.) 158°C;
IR (w, cm−1): 1631 s (CꢀN); 725 s and 729 s (arom.
CH); 1576 s, 1563 s, and 1515 s (CꢀO, CꢁH, and CꢀC);
1H-NMR (l, ppm): 1.99 and 2.08 (two s, 6H, two CH3
groups), 3.99 (t, 2H, J=9, NCH2), 4.75 (t, 2H, J=9,
OCH2), 5.38 (s, 1H, k-CH of acac), 7.06 (t, 1H, J=7.3,
arom. H-4), 7.23 (m, 2H, arom. H(3) and H(5)), 7.57
(broad d, 1H, J=7.8, arom. H(6)); 13C-NMR (l, ppm):
27.5 and 27.8 (two CH3 groups), 49.6 (OCH2), 70.3
(NCH2), 100.4 (g-CH of acac), 124.1, 125.2, 130.4, and
130.8 (four arom. CH), 131.3 (arom. C(2)), 150.1
(PdC(1)), 176.2 (OCꢀN), 186.1 and 188.0 (two CꢀO).
Anal. Calc. for C14H15NO3Pd: C, 47.82; H, 4.30; N,
3.92. Found: C, 47.42; H, 4.12; N, 4.03%.
A solution of 2,4-pentanedione (20 mg, 0.169 mmol)
in MeOH (5 ml) and a solution of KOH (9 mg, 0.161
Table 3
Crystal data, data collection, structure solution and refinement
parameters for complexes 2 and 7·CH2Cl2
2
7·CH2Cl2
Empirical formula
Formula weight
Color, habit
Crystal size (mm)
Crystal system
Space group
C18H18Cl2N2O2Pd
471.64
Orange block
0.50×0.40×0.40
Monoclinic
P21/n
C28H25Cl3N1O1P1Pd1
635.21
Light-green block
0.5×0.4×0.2
Monoclinic
P21/n
Unit cell dimensions
,
a (A)
7.848(5)
11.170(4)
11.479(4)
108.41(4)
954.8(8)
2
11.578(5)
10.786(8)
22.069(8)
93.32(3)
2751(3)
4
,
b (A)
,
c (A)
i (°)
V (A )
4.7. Chloro[2-(2-oxazolinyl)phenyl,1-C,3-N]-
(triphenylphosphine)palladium(II) (7)
3
,
Z
Dcalc. (g cm−3
)
1.641
1.533
Triphenylphosphine (27.3 mg, 0.104 mmol) was
added to a suspension of 3b (30.0 mg, 0.052 mmol) in
benzene. The mixture was stirred at r.t. for 12 h, then
the solvent was removed in vacuum. A pale yellow solid
was purified by column chromatography (1:9 ethyl
acetate–CHCl3). Yield, 57.0 mg (99%). Rf 0.67 (ethyl
acetate–toluene, 1:9); m.p. (dec.) 150–152°C; IR (w,
Absorption coeffi-
1.265
1.046
cient (mm−1
)
Diffractometer
Enraf–Nonius
CAD-4
293
Graphite-monochro- Graphite-monochro-
mated Mo–Ka
(0.71073)
Enraf–Nonius CAD4
295
Temperature (K)
,
Radiation u (A)
mated Mo–Ka
(0.71073)
cm−1): 1642 s (CꢀN), 720 s (arom. CH); H-NMR (l,
q range (°)
Index ranges
2.04–26.97
−145h50
−45k513
−285l528
6492
1
−105h510
05k514
−155l515
ppm): 4.25 (t, 2H, J=9.5, NCH2), 4.74 (t, 2H, J=9.5,
OCH2), 6.43 (dd, 1H, 3JHH=7.5, JHP=4.7, arom.
H(6)), 6.63 (dt, 1H, 3JHH=7.5, 4JHH=1.4, arom.
Reflections collected 4562
Independent
reflections
Data reduction
Absorption
correction
Min./max.
transmission
Solution method
SHELX-86) [64]
Refinement method Full-matrix
least-squares on F2 least-squares on F2
SHELXL-93) [65] SHELXL-93) [65]
Data/restraints/
parameters
2295 [Rint=0.0160] 5883 [Rint=0.0223]
3
H(5)), 6.92 (t, 1H, JHH=7.5, arom. H(4)), 7.30 (dd,
3
4
1H, JHH=7.5, JHH=1.4, arom. H(3)), 7.36 (dt, 6H,
XCAD4 [63]
3JHH=7.2, JHH=7.4 Hz, JHP=2, meta-H of PPh3),
3
4
Empirical (C scan)
0.4280 and 0.5269
Direct methods
Empirical (C scan)
0.6788 and 0.7755
Direct methods
7.43 (dt, 3H, 3JHH=7.4 Hz, 4JHH=1.2, para-H of
3
3
4
PPh3), 7.74 (ddd, 6H, JHP=11.7, JHH=7.2, JHH
=
1.2, ortho-H of PPh3); 13C-NMR (l, ppm): 51.0
(NCH2), 70.8 (OCH2); 123.8 (HC(4) of C6H4), 126.3
(HC(3) of C6H4), 128.1 (d, 3JPC=11, meta-CH of
(
(
SHELX-86) [64]
Full-matrix
4
PPh3), 130.8 (d, JPC=2, para-CH of PPh3), 130.8 (d,
(
(
1JPC=45, quat. C of PPh3), 131.0 (d, JPC=6.5, HC(5)
4
2295/0/152
5418/6/406
3
of C6H4), 133.4 (quat. C(2) of C6H4), 138.1 (d, JPC
=
Goodness-of-fit on
1.088
1.036
11, HC(6) of C6H4); Anal. Calc. for C27H23NOClPPd:
C, 58.93; H, 4.21; N, 2.55. Found: C, 59.18; H, 4.57; N,
2.81%.
F2
Final R indices
[I\2|(I)]
R1=0.0203,
R1=0.0397,
wR2=0.0536
R1=0.0234,
wR2=0.0553
0.487/−0.621
wR2=0.1098
R1=0.0686,
wR2=0.1267
0.704/−0.795
R indices (all data)
4.8. X-ray structure determinations of 2 and 7
Largest difference
Crystal data, data collection, structure solution and
refinement parameters are listed in Table 3. Unit-cell
dimensions for 7 were calculated from the setting angles
peak and hole
−3
,
(e A
)

96
I.P. Smoliako6a et al. / Journal of Organometallic Chemistry 603 (2000) 86–97
120 (1998) 4895. (d) M.P. Sibi, J. Ji, J. Org. Chem. 62 (1997)
3800. (e) A. Chesney, M.R. Bryce, R.W.J. Chubb, A.S. Bat-
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Lett. 37 (1996) 3815. (h) A.V. Bedekar, P.G. Andersson, Tetra-
hedron Lett. 37 (1996) 4073. (i) G. Desimoni, G. Faita, P.P.
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M. Neuburger, M. Zehnder, H. Ruegger, P.S. Pregosin, Helv.
Chim. Acta 78 (1995) 265.
of 25 accurately centered reflections. Two reflections
were chosen as intensity standards and were measured
every 120 min. Three orientation controls were checked
every 300 reflections. The experimental intensities for
both complexes were corrected for Lorentz and polar-
ization effects [63]. All non-hydrogen atoms (except
solvent CH2Cl2 molecule) in both structures were
refined in the anisotropic approximation. The solvent
molecule in the crystal of 7 was found disordered over
two positions with occupancy ratio 0.5/0.5. All hydro-
gen atoms were placed in calculated positions. Both
coordinates and isotropic thermal parameters for the
hydrogens of the main molecule were refined. A riding
model was applied for the H atoms of CH2Cl2 molecule
[63–65].
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5. Supplementary material
Crystallographic data (excluding structure factors)
for the structures reported in this paper have been
deposited with the Cambridge Crystallographic Data
Centre as supplementary publication no. CCDC-138520
(complex 2) and 138519 (compound 7). Copies of the
data can be obtained free of charge on application to
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK
(fax: +44-1223-336033; e-mail: deposit@ccdc.cam.
ac.uk, or www: http://www.ccdc.cam.ac.uk).
Acknowledgements
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We would like to thank the University of North
Dakota and the Russian Foundation for Basic Re-
search (Grant no. 98-03-33142) for financial support.
Undergraduate Summer Research Assistantships for
K.J.K. and D.M.W. were provided by the NSF-REU
program (Grant no. CHE-9619804).
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