Synthesis, interionic structure, and reactivity toward CO and p-methylstyrene of palladacyclic compounds bearing α-diimine ligands

Article abstract of DOI:10.1002/hlca.200690155

Palladacyclic compounds [Pd(C₆H₄(C₆H ₅C=O)C=N-R)(N-N)][X] (R=Et, ⁱPr, 2,6-ⁱPr ₂C₆H₃; N-N =bpy=2,2′-bipyridine, or 1,4-(o,o′-dialkylaryl)-1,4-diazabuta-1,3-dienes; [X]^- =[BF ₄]^- or [PF₆]^-) were synthesized from the dimers [{Pd(C₆H₄(C₆H₅C=O)C=N-R) (μ-Cl)}₂] and N-N ligands. Their interionic structure in CD ₂Cl₂ was determined by means of ¹⁹F, ¹H-HOESY experiments and compared with that in the solid state derived from X-ray single-crystal studies. [Pd(C₆H₄(C ₆H₅C=O)C=N-R)(N-N)][X] complexes were found to copolymerize CO and p-methylstyrene affording syndiotactic or isotactic copolymers when bpy or 1,4-(o,o′-dimethylaryl)-1,4-diazabuta-1,3-dienes were used, respectively. The reactions with CO and p-methylstyrene of the bpy derivatives were investigated. Two intermediates derived from a single and a double insertion of CO into the Pd-C bonds were isolated and completely characterized in solution.

Full text of DOI:10.1002/hlca.200690155

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Helvetica Chimica Acta – Vol. 89 (2006)
Synthesis, Interionic Structure, and Reactivity toward CO and
p-Methylstyrene of Palladacyclic Compounds Bearing a-Diimine Ligands
by Cristiano Zuccaccia*a), Gianfranco Bellachiomaa), Giuseppe Cardacia), Alceo Macchioni*a), Barbara
Binottib), and Carla Carfagnab)
a) Dipartimento di Chimica, Università di Perugia, Via Elce di Sotto, I-8-06123 Perugia
(e-mail: alceo@unipg.it)
b) Istituto di Scienze Chimiche, Università di Urbino, Piazza Rinascimento, I-6-61029 Urbino
Dedicated to Professor Giambattista Consiglio on the occasion of his 65th birthday
i
Palladacyclic compounds [Pd(C6H4(C6H5C=O)C=NÀR)(NÀN)][X] (R=Et, Pr, 2,6-iPr2C6H3; NÀ
N=bpy=2,2’-bipyridine, or 1,4-(o,o’-dialkylaryl)-1,4-diazabuta-1,3-dienes; [X]À =[BF4]À or [PF6]À)
were synthesized from the dimers [{Pd(C6H4(C6H5C=O)C=NÀR)(m-Cl)}2] and NÀN ligands. Their inter-
ionic structure in CD2Cl2 was determined by means of 19F,1H-HOESY experiments and compared with
that in the solid state derived from X-ray single-crystal studies. [Pd(C6H4(C6H5C=O)C=NÀR)(NÀ
N)][X] complexes were found to copolymerize CO and p-methylstyrene affording syndiotactic or isotac-
tic copolymers when bpy or 1,4-(o,o’-dimethylaryl)-1,4-diazabuta-1,3-dienes were used, respectively. The
reactions with CO and p-methylstyrene of the bpy derivatives were investigated. Two intermediates
derived from a single and a double insertion of CO into the PdÀC bonds were isolated and completely
characterized in solution.
Introduction. – There is increasing evidence that the solution structure and reactiv-
ity of organometallic compounds can be altered by noncovalent interactions. For
instance, when ionic compounds are considered, ion pairing may substantially affect
the chemical pathway of organic reactions mediated by transition-metal organometal-
lics in terms of chemo-, regio-, and stereoselectivity [1].
It has been demonstrated that NMR spectroscopy is the technique of choice for
investigating noncovalent adducts in solution, especially by NOE (nuclear Overhauser
effect) and PGSE (pulsed-field gradient spin echo) experiments (for recent reviews, see
[2]).
For several years, our group has been involved in the application of NOE [3a–c]
and PGSE [3d] NMR methodologies to determine the interionic structure in solution
(namely, the relative cation–anion orientation and aggregation level) of transition-
metal complex ionic adducts. Several combinations of anions (ranging from inorganic,
such as [BF4]À and [PF6]À, to more organic ones, like [BPh4]À, [B{3,5-(CF3)2C6H3}4]À, or
[B(C6F5)4]À) and metal geometries (octahedral, square-planar, and ‘piano-stool’) have
been considered. Generally speaking, the results have indicated that the counterion,
regardless of its nature, is very often located close to a specific position of the organo-
metallic cation. Quantum-mechanical and mechanical calculations have shown that this
is principally due to an accumulation of positive charge in a particular location of the
cationic fragment [4].
© 2006 Verlag Helvetica Chimica Acta AG, Zürich

Helvetica Chimica Acta – Vol. 89 (2006)
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Several square-planar ion pairs of the general formula [M(alkyl)(olefin)(NÀN)]X
(M=Pd or Pt, and NÀN=2,2’-bipyridine (bpy) or 1,4-diazabuta-1,3-diene derivatives)
have been investigated [5] with the two-fold objective of 1) correlating ion pairing with
catalytic activity toward CO/olefin copolymerization and 2) evaluating the accessibility
of a nucleophile to the metal center as a function of the steric hindrance in the apical
position by using the anion as a probe [6].
To check the effect of varying the ligands on the cation-charge distribution and, con-
sequently, on the interionic structure of the complexes, we here report on the interionic
structure of ortho-palladated imines of the general formula [Pd(C6H4(C6H5C=O)C=
NÀR)(NÀN)][X] derived from the metallation of a-(alkylimino) or a-(arylimino)
ketones [7]. Palladacyclic compounds have been known for a long time (for a recent
review, see [8]), and applications have been found in organic synthesis [9], bioorgano-
metallic chemistry, material sciences, as well as homogeneous catalysis [10]. While it is
well-known that a variety of unsaturated molecules can be inserted into the metal–aryl
or metal–alkyl bonds of palladacycles [11], including alkenes and CO [12] (for styrene,
see [12a], for CO, see [12f–k]), they have rarely been used as single-component cata-
lysts (precatalysts) in the alternating COÀalkene copolymerization reaction [13]. Here,
we also report on the reactivity toward CO and olefins and on preliminary catalytic
tests of selected ortho-palladated cationic complexes.
Results and Discussion. – Synthesis. Cyclopalladated dimers [{Pd(C6H4(C6H5C=
i
O)C=NÀR)(m-Cl)}2] with R=Et (1), Pr (2), or 2,6-iPr2C6H3 (3) were synthesized by
the reaction [14] of Na2[PdCl4] with a small excess of the proper a-imino ketone [15]
in MeOH (Scheme 1). Cationic complexes 4 and 5 were obtained by the reaction of
complexes 1 and 2 with bpy in MeOH, respectively, in the presence of a large excess
of NH4[PF6]. Complexes 6–10 were synthesized by adding Ag[BF4] to a solution con-
taining the dimer 1 and a suitable NÀN ligand in CH2Cl2, followed by filtration of AgCl
and precipitation of the final product with hexane (Scheme 1). Both the dimers and cat-
ionic complexes were stable in the solid state. The cationic compounds showed little
sign of decomposition in CH2Cl2 solution after several days at room temperature
under an inert atmosphere.
Intramolecular Characterization in Solution. All complexes were characterized at
1
1
room or low temperature by H-, 13C-, and 19F-NMR spectroscopy and H,1H-COSY,
1H,1H-NOESY, 19F,1H-HOESY (=heteronuclear Overhauser enhancement spectro-
scopy), 1H,13C-HMQC, and 1H,13C-HMBC experiments. ortho-Metalation at the phenyl
substituent bonded to the C=N group can be inferred from the chemical shifts of the Ca
resonance (see Scheme 1 for numbering), which were in the range from d(C) 153.7 to
159.8, while kN-coordination to Pd is supported by the chemical shifts of the Cc reso-
nance (d(C) 181.2–185.6), in agreement with literature results with similar compounds
[7]. In the cationic complexes 4–6, a dynamic process that averages the two pyridine
rings is present [6b]. In the case of 4 and 5, broad peaks were observed for the bpy pro-
tons HÀC(6)/HÀC(6’), HÀC(5)/HÀC(5’), HÀC(4)/HÀC(4’), and HÀC(3)/HÀC(3’)
(see Scheme 1 for numbering) at room temperature. In contrast, sharper resonances
1
were observed in the H-NMR spectrum of 6 at room temperature. This was due to
the marked differentiation of the H-atoms of the two pyridine rings of bpy due to
the strong shielding effect exerted by the almost perpendicular orientation of the

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Helvetica Chimica Acta – Vol. 89 (2006)
Scheme 1
i) MeOH, 2,2’-bipyridine, NH4[PF6]. ii) CH2Cl2, N,N-ligand, Ag[BF4].
ortho-disubstituted aryl ring on the pyridine ring of bpy in cis position to the imine N-
G
atom (e.g., HÀC(6’) and HÀC(6) resonate at d(H) 9.07 and 5.7, resp.). Since similar
dynamic processes [5b] are also present for complexes 7–10, NMR investigations
AHCTREUNG
were undertaken at low temperature, where the dynamic motion that interconverts
the two halves of the NÀN ligand is slow on both the chemical-shift and T1 time scales.
i
The Me resonances of the alkylimino group (or those of the Pr groups in the case of
1
complex 6) are the starting point for assigning all the H and 13C resonances. In the
case of bpy complexes, starting from the selective NOE interaction of the Me groups
with HÀC(6), all the other bpy resonances can be easily assigned, following either
the scalar or dipolar connectivities. The HA resonance can then be recognized due to
the strong NOE interaction with HÀC(6’) and, finally, the remaining HB, HC, and
HD of the metalated phenyl ring are assigned by means of the 1H,1H-COSY plot.
It is known that aromatic a-diimine ligands tend to orient the aryl rings almost per-
pendicularly to the square-planar coordination plane when they coordinate to a metal
center [16]. Analogous to previously studied compounds [5b][17], for complexes 7–10,
it is possible to discriminate between the two halves of the NÀN ligand lying ‘up’ or
‘down’ with respect to the square-planar coordination plane. For example, among

Helvetica Chimica Acta – Vol. 89 (2006)
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the four resonances of the aryl Me groups of complex 7, only the one at d 2.46 (Me(14))
selectively interacts with the Ho of the benzoyl group, while that at d 2.35 (Me(13))
interacts with the Me group of the Et substituent1). Unambiguous discrimination of
Me(15) and Me(16) for complexes 7 and 8 were derived from the observation of a
very weak NOE between the Ho resonance and the Me resonance at d 2.31, conse-
quently assigned to Me(16). However, Me(11) and Me(12) of 7 cannot be differentiated
because all six Me resonances fall within the range between d 2.46 and 2.31, making it
difficult to observe cross-peaks between them in the 1H,1H-NOESY plot.
For complexes 9 and 10, HÀC(14) and HÀC(13) can be recognized due to their
selective NOEs with the Ho-atoms of the benzoyl group, and the Me group of the Et
substituent, respectively. In addition, the presence of iPr substituents makes it possible
to differentiate Me(11) from Me(12). Finally, NOE interactions are present between
either Ho or Me(20f), which allows HÀC(16), HÀC(13), and HÀC(15) to be assigned
as shown in Fig. 1.
1
Fig. 1. Two sections of the H,1H-NOESY plot (CD2Cl2, 230 K, mixing time 800 ms) of complex 9
1
)
Supporting information is available upon request from C. Z. or A. M.

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Solid-State Structure of Complexes 4 and 6. Single crystals of compound 4 were
obtained from CH2Cl2/hexane, while crystals of 6 suitable for an X-ray analysis were
grown by layering MeOH and then hexane on top of a concentrated CH2Cl2 solution.
Both crystals belong to the P21/c space group. The unit cell contains four molecules in
the case of complex 4, while there are four molecules of the organometallic fragment
and four molecules of MeOH in the case of complex 6. Selected bond distances and
angles are reported in Table 1, and ORTEP drawings of the cationic moieties are
shown in Fig. 2. The Pd-atom presents a distorted square-planar coordination geometry
that can be described in terms of five interplanar angles, namely a (between the PdÀ
N(1)ÀN(2) and PdÀC(1)ÀN(3) plane), b (between the PdÀN(1)ÀN(2) and the
mean N(1)ÀC(32)ÀC(31)ÀN(2) plane), b’ (between the PdÀC(1)ÀN(3) and the
mean C(1)ÀC(6)ÀC(7)ÀN(3) plane), g (between the two pyridine rings of bpy), and
g’ (between the metalated-ring and the C(15)ÀN(3)ÀC(7)ÀC(8) planes) [18]. In 4,
a=15.1(8)8, b=19.4(6)8, b’=3.6(5)8, g=16.9(7)8, and g’=4.7(6)8, while in 6,
a=13.2(4)8, b=16.5(3)8, b’=7.1(0)8, g=18.3(0)8, and g’=14.5(9)8. Since a bow-step
conformation requires aꢀ08, and a twist conformation matches with a pretty large
value of a (ꢀ20–258) but small values of b and g (<58) [18a] the values observed
for 4 and 6 indicate that these two limit conformations do not actually describe the
overall observed geometry. The distortion at the bpy ligand is, however, more similar
to that observed in bis-metalated [Pd(1,1’-biphenyl-2,2’-yl)(bpy)] in which
g=17.6(6)8 [19]. The angle between the C(1)ÀC(6)ÀC(7)ÀN(3) mean plane and the
ortho-substituted phenyl ring (C(15) to C(20)) is 88.6(9)8 in 6, in agreement with the
solution-NMR results (see above). The PdÀN(2) bond distances (2.172(2) Å in 4 and
2.158(4) Å in 6) are ca. 0.12 Å longer than the PdÀN(1) ones (2.056(3) Å in 4 and
2.037(4) Å in 6), reflecting the influence exerted by the s-bonded C(1) atom in trans
position. The PdÀC(1) bond distances (1.989(3) Å in 4 and 2.003(5) Å in 6) are compa-
rable to those found for other sp2 C-atoms, which are either trans to a bpy N-atom or
involved in cyclometalation (2.000 Å [19], 2.009 Å [19], 1.986 Å [20]).
Table 1. Coordination Bond Lengths [Å] and Angles [deg] for Complexes 4 and 6
4
6
4
6
PdÀC(1)
PdÀN(1)
PdÀN(2)
PdÀN(3)
1.989(3)
2.056(3)
2.172(2)
2.055(2)
2.003(5)
2.037(4)
2.158(4)
2.034(4)
C(1)ÀPdÀN(3)
C(1)ÀPdÀN(1)
N(3)ÀPdÀN(1)
C(1)ÀPdÀN(2)
N(3)ÀPdÀN(2)
N(1)ÀPdÀN(2)
79.90(12)
98.00(12)
172.62(9)
166.87(11)
106.08(9)
77.48(9)
79.45(18)
99.65(19)
173.14(16)
169.51(18)
103.91(15)
78.19(17)
Interionic Structure by HOESY-NMR Experiments. The interionic structure was
investigated in CD2Cl2 at low temperature by 19F,1H-HOESY-NMR experiments. The
19F,1H-HOESY plot of 4 recorded at 200 K is reported in Fig. 3,a. After having scaled
the NOE intensity for the number of equivalent nuclei [21], the 19F,1H interactions fol-
lowed the order: HÀC(6)ꢀHÀC(5)>HA ꢀCH2 >HÀC(4), HÀC(3)>HB >HÀ
C(6’)ꢀHÀC(3’)>Me. At 200 K, Hos appear as broad resonances and are not suitable
to obtain information on the anion position. A 19F,1H-HOESY experiment was also

Helvetica Chimica Acta – Vol. 89 (2006)
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Fig. 2. ORTEP Representations (50% ellipsoid probability) showing the cationic moieties of a) 4 and
b) 6. H-Atoms have been omitted for clarity.
recorded at 230 K where these resonances are relatively sharp; interionic interactions
of an intensity comparable to that with HA were observed for the Hos atoms. All these
findings indicate that the anion is mainly located in proximity to the EtN=C and the
pyridine moiety of bpy that is in trans position relative to the PdÀC s-bond. A similar
anion location was previously found in the [Pd(h1,h2-C8
N
N
[4b][6b]; in that case, however, the anion was located further behind the bpy ligand
(the strongest contacts were observed with HÀC(3)). This anion shift was probably
due to the presence of an additional positively polarized imine C-atom in 4.
In the solid state, cation couples of 4 are surrounded by several anions. The closest
[PF6]À anion with respect to the Pd-atom (Pd···PA distance=5.431(9) Å, Fig. 4,a) lies
above the square-planar coordination plane, partially shifted toward the imine moiety,

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Figure 3. a) 19F,1H-HOESY Spectrum (CD2Cl2, 230 K, mixing time 800 ms) of complex 4, and b) 19F,
1H-HOESY spectrum (CD2Cl2, 217 K, mixing time 800 ms) of complex 6.
on the same side as the phenyl of the benzoyl group. The HOESY Data in solution can-
not be rationalized by this anion–cation orientation alone. For example, the PA ···HÀ
C(36), and PA ···HÀC(27) distances are 5.521(8) and 6.371(9) Å, respectively, while a
stronger HOESY contact is observed between the anion and HÀC(27) (=HÀC(6) in
the NMR numbering, Scheme 1). The remaining anions are positioned on the periph-
ery, relatively distant from the metal center. Only two of them show a relatively
short Pd···P distance. In particular, in orientation ‘B’ (Pd···PB distance=6.814(10)
Å, Fig. 4,a), the P-atom of the anion is positioned only 0.271 Å away from the mean

Helvetica Chimica Acta – Vol. 89 (2006)
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Figure 4. a) Ball-and-stick representation of compound 4 showing the location of the anions around
the organometallic cations. b) Ball-and-stick representation of the three anions that are closest to a cat-
ion of 6 in the solid state
PdÀC(1)ÀN(1)ÀN(2)ÀN(3) plane, strongly shifted toward the pyridine ring in trans
position with respect to the PdÀC s-bond. Partial occupation of such an orientation,
in which the anion is very close to HÀC(27) and HÀC(28) (i.e. HÀC(6) and HÀC(5)
in the NMR numbering, Scheme 1), could account for the strongest HOESY interionic
contacts observed in solution ([PF6]À with HÀC(6) and HÀC(5)). In orientation ‘C’
(Pd···PC distance=7.508(11) Å, Fig. 4,a) the anion is closer to the metallated phenyl
ring, 2.470(12) Å away from the mean PdÀC(1)ÀN(1)ÀN(2)ÀN(3) plane, on the
same side as the phenyl ring of the benzoyl group. Partial occupation of this orientation
could explain the observed interionic interaction in solution between the anion and HÀ
C(6’), HA, and HB.

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The introduction of the bulkier 2,6-iPr2C6H3 substituent at the imine N-atom signif-
icantly influences the interionic structure in solution. The low-temperature (217 K)
19F,1H-HOESY plot of 6 is reported in Fig. 3,b. 19F,1H-Cross-peak intensities follow
the order: HÀC(3), HÀC(3’), HÀC(4’)>HÀC(5’)>HÀC(4)>>HÀC(6’)ꢀHA ꢀHÀ
C(5)>HB ꢀHC. It is worth noting that the anion does not show any contact with HÀ
i
C(6) or the Pr H-atoms. This means that it is now located close to the pyridine ring
of bpy in a cis position relative to the PdÀC s-bond, and it approaches the cation
from a lateral trajectory. While it is not surprising that the steric protection provided
by the bulky aryl moiety pushes the anion far away from the imine ligand [22], it is
remarkable that the anion occupies a peripheral position instead of staying above
and below the square-planar coordination plane, as it usually occurs.
In the solid state, each cation of 6 is surrounded by several [BF4]À anions, none of
which has a particularly short Pd···B distance. The three closest anions (Pd···B distan-
ces of 6.344(5) Å (BA), 7.735(9) Å (BB), and 8.135(8) Å (BC), Fig. 4,b) are located on
the periphery of the bpy ligand, shifted toward the pyridine ring cis to the PdÀC s-
bond (BA and BC) or at an intermediate position between the two pyridine rings
(BB). The interionic structure observed in solution is quite well-described by a partial
occupation of all three orientations.
The replacement of the ‘flat’ bpy ligand of 6 with 1,4-(o,o’-dialkylaryl)-1,4-diaza-
buta-1,3-diene ligands such as in 7–10 proved to be very useful for gaining more infor-
mation about cation–anion interactions. As stated above, the advantage of these ligands
is that they have ‘reporters’ spatially distributed above and below the square-planar
coordination plane. Previous investigations carried out with Pd [5b] and Pt [6a][17]
complexes showed that the perpendicular orientation of the aryl moieties forms a bar-
rier that blocks the anion approach to the metal center. In complex 7, as expected, the
anion interacted with the six Me groups of the a-diimine ligand. The interactions with
Me(11) and Me(12) were the strongest, but it is worth noting that the anion/Me(16) and
anion/Me(14) cross-peaks were twice as strong as the corresponding anion/Me(13) and
anion/Me(15) cross-peaks1). This provides clear evidence that the anion prefers to
approach the cation from the same side as the square-planar coordination plane,
where the phenyl ring of the benzoyl group lies. This preference is probably dictated
by the electronic effect of the benzoyl group. In fact, the anion tends to avoid the
two lone pairs present at the O-atom, while it prefers to interact with the partial pos-
itive charge that could be delocalized into the phenyl ring [6a].
Essentially the same results were obtained for complexes 8–10. Unfortunately, in
1
the H-NMR spectrum of complex 9, the resonances of the Me groups belonging to
i
the Pr substituents are not well separated; therefore, a more detailed anion–cation
structural relationship could not be determined. In the case of complexes 8 and 10,
which bear the acenaphthylene backbone, the strongest interionic interactions were
observed between the anion and H-atoms on the backside of the ligand, but there
was an overall decrease in specificity. This is in agreement with previous observations,
and it can be attributed to a reduced tendency to form ion pairs. This may be due to the
difficulty that the counteranion has in approaching the imine C-atoms of the coordi-
nated ligand, because it is sterically protected by the acenaphthylene moiety [5b]. In
complex 10, the interaction of Me(18f) with the anion is stronger than that of
Me(17f), confirming that [BF4]À prefers the side cis to the phenyl ring of the benzoyl

Helvetica Chimica Acta – Vol. 89 (2006)
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group. On the other hand, the anion/Me(18f) cross-peak is larger than that between the
anion and Me(20f), as in complex 4, thus confirming the preference for the side cis to
the imine of the metalated ligand.
Copolymerization of CO and p-Methylstyrene. Complexes 4 and 6–8 were tested as
catalysts for the CO/p-methylstyrene copolymerization. The catalytic reactions were
carried out in CH2Cl2 at room temperature and 1 atm pressure of CO. The results
are summarized in Table 2. Complexes 4 and 6 show comparable activities in producing
syndiotactic polyketones having similar molecular weights and polydispersivity, and
with the usual degree of stereoregularity (ca. 85% of uu triad). In particular, productiv-
ities of 33 and 27 gCP · gPdÀ1 · hÀ1 and molecular weights of 31,200 and 25,200 were
observed for complexes 4 and 6, respectively. Different behaviors were observed for
the CO uptake for 4 and 6. The former did not show any induction period, while the
latter showed an induction period of ca. 15 min1).
Table 2. Copolymerization Results
Complex
Reaction time [h]
Productivity
[g CP/g Pd]
Stereoregularity
Mw (Mw/Mn)
4
6
7
3.5
3.5
51
114
94
18
syndiotactic
syndiotactic
isotactic
31200 (2.0)
25200 (2.0)
9100 (1.3)
Interestingly, complex 7 produced prevalently isotactic polyketones (ca. 79% of ll
triad), while showing a much lower productivity (0.4 gCP·gPdÀ1 ·hÀ1). Thus, an increase
of the steric hindrance on the apical positions dramatically changed the catalyst stereo-
specificity2) [23]. The use of even more sterically demanding ligands, as in 8, completely
suppressed the catalytic activity.
Reactivity toward CO and p-Methylstyrene. To obtain some insights into the initial
steps of the copolymerization reaction, the reactivity of complexes 4 and 5 toward the
monomers was investigated by NMR. As expected, the reactivity of complexes 4 and 5
was identical; the reactions that occurred in the case of 5 are illustrated in detail.
a) Reactivity toward CO. When CO was bubbled into a CH2Cl2 solution of 5 at room
temperature, the initially yellow solution became dark yellow and then colorless, while
an amorphous dark precipitate separated from the solution. NMR Analysis of the
residual solution showed that 3-benzoyl-2-isopropylisoindolin-1-one (12) was quantita-
tively formed (Scheme 2)3) [24]. Similarly, 11 was obtained from 4.
To trap the intermediates, the reaction of 5 with CO was carried out under strictly
anhydrous conditions. The reaction product 14 (Scheme 3), which appeared to be stable
under CO atmosphere, was completely characterized by multinuclear and multidimen-
sional NMR spectroscopy at room temperature.
Key NMR features that allowed us to propose the formation of complex 14 include the following: i)
The imine C=N resonance at d 182.6 of 5 disappeared, and the signals of three new quaternary C-atoms
2
)
)
We have observed this effect before (see [5a]), and it will be the subject of a future report [23].
Keto amides that are structurally similar to 12 were recently investigated [24].
3

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Helvetica Chimica Acta – Vol. 89 (2006)
Scheme 2
Scheme 3
appeared at d 206.0, 168.8, and 100.7. The resonances at d 168.8 (Ce) and 100.7 ppm (Cc) showed long-
range correlation with HA and HD, respectively, while the resonance at d 206.0 (Cf) did not exhibit any
long-range correlations. ii) The resonance of Ca appeared at d 131, i.e., at lower frequency by ca. 29
ppm than in complex 5, indicating aryl depalladation. iii) The carbonyl resonance of the benzoyl
group appeared at d 209.9, shifted to higher frequency by ca. 16 and ca. 10 ppm with respect to complex
5 and the free a-imino ketone ligand, respectively, in agreement with the coordination to the Pd-atom
through the O-atom [25]. iv) The bpy ligand showed eight separated resonances, in agreement with
the magnetic inequivalence of the two pyridine moieties of the NÀN ligand that were in a slow exchange

Helvetica Chimica Acta – Vol. 89 (2006)
1535
regime with respect to the chemical-shift time scale. The proposed structure was also supported by the
fact that we were unable to detect any NOEs between HÀC(6) and HÀC(6’) and any of the H-atoms
belonging to the acyl ketone ligand.
The formation of complex 14 is the result of two consecutive insertion reactions of
CO into the PdÀaryl and PdÀalkyl bonds. The first CO inserts into the PdÀaryl bond of
complex 5, forming the putative imino-acyl palladacycle intermediate [12j][26], which
undergoes a formal insertion of the C=NR moiety into the PdÀacyl bond [12f] (com-
plex 16 in Scheme 3), which then inserts a second CO molecule to form 14. Interestingly,
complex 14 is analogous to the intermediate invoked to rationalize the double incorpo-
ration of CO or tert-butyl isocyanide in cationic complexes similar to 5 bearing a
diphosphine ligand [12i]. Complex 16 was, indeed, obtained by decarbonylation of 14
through several freeze-pump-thaw degassing cycles. It was characterized by multinu-
clear and multidimensional NMR spectroscopy.
Complex 16 features a quaternary C-atom resonance at d 45.7 (Cc), consistent with an aliphatic CÀ
Pd bond. In agreement with bpy coordination, HÀC(6’) shows a medium-size NOE interaction with one
of the Me groups of the iPr substituent, and a smaller one with HA; it is interesting to note that HÀC(6’)
resonates at relatively low frequency (d(H) 6.88) suggesting an almost perpendicular orientation of the
isoindoline benzo moiety with respect to the square-planar coordination plane. The carbonyl resonance
of the benzoyl group appears at d 217.8. This value is shifted to higher frequency by ca. 25, 18.5, and 13
ppm with respect to complex 5, the free a-imino ketone ligand, and the ‘ketonyl’ complex trans-[Pd(CH2-
COPh)Cl(PPh3)2], respectively [27]. These data strongly suggest that the carbonyl group is coordinated
to the Pd-atom, affording the proposed four-membered palladacycle involving a (carbonyl-kO)alkyl-kC
moiety (Scheme 3).
Alternatively, complex 16 could be a dimer, in analogy with the complex [{cis-
(PdPPh3)2)}2
N
N
performed PGSE measurements on a mixture containing 13 (ca. 2 mM) and 15 (ca. 3
mM), obtained from the carbonylation reaction of 4. The starting complex 4 (ca. 6
mM) was used as an external standard. The results indicate that the volumes of 13
and 15 are ca. 15–25% greater than that of compound 4. While these values are a little
larger than what was expected for the addition of one or two CO molecules, respec-
tively, they strongly suggest that complexes 13 and 15 are monomeric (in principle, if
15 were a dimer, its volume should be ca. 110–120% larger than that of the parent com-
pound 4). We believe that other possible formulation of complexes 15 and 16 such as h3-
oxoallyl or h3-benzyl species are unlikely for the following two reasons: i) a relevant
low-frequency shift of the carbonyl resonance of the benzoyl group would be expected
in the case of an h3-oxoallyl species [28][29]; ii) significant low-frequency shifts in both
1H- (d<7) and 13C-NMR (dꢀ110–100) spectra would be expected for the aromatic H-
and C-atoms involved in the h3-benzyl structure [30].
Addition of H2O to both solutions of 14 or 16 resulted in the quantitative formation
of 3-benzoyl-2-isopropylisoindolin-1-one (12), and precipitation of an amorphous dark
solid. Interestingly, the formation of 12 was accompanied by the disappearance of both
the bpy and anion resonances in the 1H- and 19F-NMR spectra, respectively.
Neither complex 14 nor 16 inserted p-methylstyrene after 12 h at room tempera-
ture, even when the latter was present in a 5- to 50-fold excess. In addition, compounds

1536
Helvetica Chimica Acta – Vol. 89 (2006)
Scheme 4
14 and 16 were the main products when the carbonylation of 5 was carried out in the
presence of an excess of p-methylstyrene (Pd/p-methylstyrene molar ratio 1:3).
b) Reactivity toward p-Methylstyrene. The reaction of 5 with p-methylstyrene was
much slower than that with CO. When complex 5 in CH2Cl2 was left at room temper-
ature overnight in the presence of a large excess of p-methylstyrene (40- to 150-fold
excess), it was clearly transformed into complex 18 (Scheme 4). Unfortunately, all
attempts to obtain single crystals of 18 suitable for X-ray investigation were unsuccess-
ful. Consequently, complex 18 was characterized in solution by IR and NMR spectro-
scopy.
The IR spectrum of 18 in CH2Cl2 showed two bands at 1625 and 1605 cmÀ1. The 1H-NMR established
that two species are present in solution in a ca. 85 :15 molar ratio, and the 1H-EXSY spectrum indicated
that they interconvert. Due to partial overlapping, only the resonances of the major component could be
completely recognized. Key NMR features are: i) signals of two quaternary C-atoms at d 76.6 (Cc) and
188.4 (Cd); they show long-range correlations with HD and Ho, respectively, while none of them show
1H,13C single-bond correlations. ii) A broad resonance is present at d ca. 6.2 (NH). This resonance
does not show any 1H,13C single-bond correlation and appears as a br. d (or as a br. t in case of 17 obtained
from 4). iii) 1H,13C-HMBC and 1H,1H-NOESY Experiments demonstrate that the styryl unit is attached
at Ca, while the olefinic coupling constant (Jꢀ16 Hz) indicates a trans geometry of the C=C bond. iv)
Strong dipolar interactions are observed between HÀC(6’) and HD, as well as between the NH and iPr
1
moieties and HÀC(6) in the H,1H-NOESY experiment1). All these NMR observations are consistent

Helvetica Chimica Acta – Vol. 89 (2006)
1537
with the proposed structure for complex 18; in particular, the chemical shift of Cc (d 76.6) is similar to that
recently reported by Lu and Peters [31] for analogous Pd complexes that, in some cases, were structurally
characterized in the solid state by X-ray diffraction studies.
In principle, other structural arrangements can be written for compound 18. A binu-
clear Cc-bound palladacycle, which could be formed by combining two molecules of 18
either through the carbonyl, the amine, or the alkene functionalities, can be ruled out
because PGSE measurements in CD2Cl2 indicate that compound 17 (from 4) has a vol-
ume similar to that of complex 7, and a ca. 50% larger volume than 4. Since a 33% vol-
ume increment would be expected on passing from 4 to 17, these data strongly suggest
that dimerization is not occurring. Mononuclear structures involving coordination by
the C=C bond do not seem to be supported by NMR data, judging from the HÀ
C(8)/HÀC(9) and C(8)/C(9) chemical shift (d(H) 7.05, d(C) 133.9 and 123.43, resp.).
In addition, an h3-benzyl structure is not consistent with the d(C) and d(H) values of
the CA to Ca aromatic ring [30].
A plausible mechanism for the formation of 18 is an olefin insertion into the PdÀ
aryl bond, followed by b-hydride elimination to form a putative PdÀH species, which
then undergoes internal addition at the C=N bond. In contrast to 16, compound 18
do not react with H2O in CH2Cl2. At room temperature in CD2Cl2, complex 18 did
not insert CO; rather, imino ketone 19 was formed quantitatively (Scheme 4) together
with a large amount of a dark precipitate. With the formation of 19, both the bpy and
anion resonances disappeared in the 1H- and 19F-NMR spectra.
c) Implications in Catalysis. The results discussed above suggest that the isolated
and characterized intermediates of the carbonylation and of the reaction with p-meth-
ylstyrene, namely complexes 13–18, do not directly enter the catalytic cycle of the
copolymerization reaction; they are probably off-loop species. In fact, complexes
13–16 did not insert p-methylstyrene even after a period three times longer than the
overall polymerization time, while reacting 18 with CO resulted in the formation of
the substituted a-imino ketone 19. A sequential insertion was never observed. Conse-
quently, the cationic complexes tested in the CO/p-methylstyrene copolymerization
should be considered as pre-catalysts. According to the literature [32], the ‘real’ active
species is supposed to be a hydropalladium complex bearing the NÀN ligand. To obtain
evidence regarding the formation of [PdH] complexes, we prepared a complex 4’ sim-
ilar to 4, with the [BARF]À (=[B{3,5-(CF3)2C6H3}4]À) counterion instead of [PF6]À in an
attempt to avoid the precipitation of Pd and bpy and, thereby give the possibility of
detecting hydride species. Carbonylation of 4’ in nonanhydrous CD2Cl2 was then fol-
lowed by NMR. Indeed no precipitate was observed. As expected, compound 11 was
1
formed along with several other species. The resonance at d À14.8 in the H-NMR
spectrum indicated the formation of [Pd2(m-CO)(m-H)(NÀN)2][BARF] (NÀN=bpy),
which had been previously characterized by us [33], and which supports the formation
of the hydropalladium intermediate.
Conclusions. – We have established that the novel palladacyclic compounds
[Pd{C6H4(C6H5C=O)C=NÀR}(NÀN)][X] can promote the copolymerization reaction
of CO and p-methylstyrene, when the NÀN ligand is not sterically demanding in the
apical position, affording syndiotactic (NÀN=bpy) and isotactic (NÀN=(2,6-

1538
Helvetica Chimica Acta – Vol. 89 (2006)
Me2C6H3)ÀN=C(Me)ÀC(Me)=NÀ(2,6-Me2C6H3)) copolymers. The reaction of the
palladacyclic compounds 4 and 5 with CO were investigated in detail, and two species
derived from a single (15 and 16) and a double (13 and 14) CO insertion into the PdÀC
bonds were isolated and characterized in solution by multinuclear and multidimen-
sional NMR spectroscopy. The reaction of 4 and 5 with p-methylstyrene was also inves-
tigated, and the reaction products 17 and 18, respectively, were characterized. Finally,
the relative anion–cation orientation was determined both in solution and solid state
(for 4 and 6) by means of 19F,1H-HOESY NMR spectroscopy and X-ray single-crystal
diffraction studies, respectively. The anion position in solution is strongly dependent on
the steric and electronic properties of the ligand, and it is only vaguely similar to that
observed in the solid state.
We thank the Ministero dell’Istruzione, dell’Università e della Ricerca (MIUR, Rome, Italy), Pro-
gramma di Rilevante Interesse Nazionale, Cofinanziamento 2004–2005, for support.
Experimental Part
General. Manipulation of all complexes was carried out either in air or by using standard Schlenk or
high-vacuum techniques. N2 was deoxygenated and dried by passage through two purification towers
charged with activated R3-11G-BASF catalysts and 4-Å activated molecular sieves, respectively. Unless
otherwise stated, solvents were dried and purified by standard methods and freshly distilled under N2. p-
Methylstyrene was dried over calcium hydride and distilled before use. The other CP-grade chemicals
were used as received. CD2Cl2 (Cortec) was either degassed and stored over 3 Å molecular sieves, vac-
uum-distilled from calcium hydride directly into a 5-mm J. Yang NMR tube, or used as received. CO
(CP grade 99.99%) was supplied by Air Liquide. a-Imino ketones, were synthesized according to [15].
1D and 2D 1H-, 13C{1H}-, and 19F-NMR Spectra, 13C{1H}-ATP, 1H,1H-COSY, 1H,1H-NOESY, 1H,13C-
HMQC, and 1H,13C-HMBC experiments: Bruker-Avance-DRX-400 spectrometer equipped with a
Great 1/10 gradient unit and a QNP probe with a Z-gradient coil; d in ppm with external referencing
rel. to SiMe4 (1H and 13C) and CCl3F (19F), J in Hz. Typical 2D 1H,1H-NOESY and 19F,1H-HOESY
1
plots were recorded with a mixing time of 500–800 ms. H-PGSE Experiments were acquired by using
the standard stimulated echo pulse sequence [34] at 296 K without spinning. Samples having concentra-
tions in the range 2–6 mM were prepared in CD2Cl2. The shape of the gradients was rectangular, their
duration was 4 ms, and their strength was varied during the experiments. All the spectra were acquired
by using 32 K points and a spectral width of 5000 Hz, and processed with a line broadening of 1.0 Hz.
Gradients were calibrated with a sample of HDO (0.04%) in D2O (known diffusion coefficient in the
G
range 274–318 K) [35] under exactly the same conditions as with the sample of interest. The residual sol-
vent signal at d 5.32 was used as internal standard to take into account random changes in the actual
temp. inside the probe as well as gradient-strength reproducibility. The data were treated according to
a reported methodology [36]. Elemental analyses (C, H, N): Fisons-Instruments-1108 CHNS-O elemen-
tal analyzer.
Copolymerization Reactions. In a typical copolymerization reaction, the PdII complex (0.14 mmol)
was dissolved at r.t. in CH2Cl2 (5 ml) under N2, then p-methylstyrene (ca. 5.5 ml, 42 mmol) was added
(olefin/Pd molar ratio 300 :1). The resulting soln. was transferred into a thermostated Schlenk flask
equipped with a CO gas line and a tank for the CO. The soln. was allowed to react for 3.5 h at 228.
The resulting gray polymer was precipitated with MeOH and washed with MeOH. To remove metallic
Pd, the polymer was redissolved in CHCl3, filtered through Celite, precipitated with MeOH, washed
with MeOH, and dried under vacuum. For NMR characterization, samples were prepared by dissolving
ca. 35 mg of the copolymer in (CF3)2CHOH/CDCl3 1:1 (v/v). The molecular weights (Mw) of polymers
and the mass distributions (Mw/Mn) were determined by gel-permeation chromatography vs. polystyrene
standards. The analyses were recorded on a Knauer HPLC (K-501 pump; K-2501-UV detector) with a

Helvetica Chimica Acta – Vol. 89 (2006)
1539
PLgel 5-mm 104 Å GPC column; CHCl3 flow rate 0.6 ml/min). Samples were prepared by dissolving the
copolymer (2 mg) in CHCl3 (10 ml). The statistical calculations were performed with the Bruker-Chrom-
star software program.
X-Ray Crystallography. Single crystals of complexes 4 and 6, suitable for X-ray diffraction, were
obtained as described above. Data were collected on a Xcalibur (CCD areal) diffractometer of Oxford
Instr. by using Mo-Ka graphite-monochromated radiation (l 0.71069 Å). The w-phi scans and the frame
data were acquired with the CRYSALIS (CCD 171) software at r.t. The crystal-to-detector distance was
65.77 mm. The frames were processed with the CRYSALIS (RED 171) software to give the hkl files cor-
rected for scan speed, background, Lorentz, and polarization effects. Standard reflections were measured
periodically and showed no apparent variation in intensity during data collection in either of the com-
plexes, so, no correction for crystal decomposition was necessary. The data were corrected for absorption
using semiempirical multiscan methods [37].
The structures were solved by the direct methods with the SIR97 [38] program and refined by the
full-matrix least-squares method on F2 with the SHELXL-97 [39] WinGX [40] version. All non-H-
atoms were refined anisotropically. The H-atoms were added at the calculated positions and refined
by using a riding model.
In the crystal of complex 6, a molecule of MeOH was present that probably came from the crystal-
lization process. The two atoms (C, O) of MeOH were refined anisotropically, but no H-atom was added.
Selected bond lengths and angles are given in Table 1, while the structural parameters and the refine-
ments for the two complexes are given in Table 3. Atomic coordinates, anisotropic displacement coeffi-
cients, and an extended list of interatomic distances and angles are available as supporting information1).
CCDC 295788 and CCDC 295789 contain the supplementary crystallographic data for this paper. These
data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif from the Cambridge Crys-
tallographic Data Centre.
Di-m-chlorobis{2-[1-(ethylimino-kN)-2-oxo-2-phenylethyl]phenyl-kC}dipalladium (1). Na2[PdCl4]
(1.0 g, 3.4 mmol) was suspended in freshly dist. MeOH (20 ml) and ligand EtÀN=C(Ph)ÀC(Ph)=O
(0.9 g, 3.8 mmol) was added. After 1 d, the yellow precipitate that formed was separated by filtration,
1
3
rinsed with cold MeOH and dried i.v.: 1.14 g (89%) of 1. H-NMR (CD2Cl2, 298 K): 8.02 (d, Jo,m =7.4,
Ho); 7.77 (t, 3Jp,m =7.4, Hp); 7.60 (t, 3Jm,p =3Jm,o =7.4, Hm); 7.47 (t, 3JB,A =3JB,C =7.9, HB); 7.12 (d,
3JA,B =7.9, HA); 6.99 (dd, 3JC,B =7.9, 3JC,D =7.1, HC); 6.79 (d, 3JD,C =7.1, HD); 3.55 (m, MeCH2); 1.44
(m, MeCH2).
Di-m-chlorobis{2-[1-(isopropylimino-kN)-2-oxo-2-phenylethyl]phenyl-kC}dipalladium
described for 1, with Na2[PdCl4] (0.5 g, 1.7 mmol), MeOH (20 ml) and PrÀN=C(Ph)ÀC(Ph)=O (0.47
(2).
As
i
Table 3. Crystal Data and Details of Refinements for Complexes 4 and 6
4
6
4
6
Formula
C26
H22
U
U
G
N
R
G
O2
Pd m(Mo-Ka) [mmÀ1
]
0.840
0.572
M
643.84
Total data collected
Unique obs. data
26144
9675
24273
10007
Cryst. system monoclinic
Space group
a [Å]
b [Å]
P21/c (no. 14)
11.229(5)
16.245(5)
14.355(5)
94.123(5)
2611.8(17)
4
P21/c (no. 14)
10.736(5)
27.099(5)
12.726(5)
103.89(5)
3594(2)
4
Criterion for observation
Unique data used in the
refinement (NO)
No. of params. refined (NV) 351
Rint
wR(F2)
G.o.f.
Mean shift/esd, final cycle
Max pos. electron dens.
Max neg. electron dens.
q range [8]
F0 >4s(F0)
7630
F0 >4s(F0)
7205
c [Å]
444
b [deg]
V [Å3]
Z
0.0353
0.0619
0.932
0.000
0.385
0.0497
0.1313
1.051
0.001
0.601
À0.738
dcalc [g mÀ3
Cryst. size
[mm]
]
1.637
1.378
0.15×0.10×0.07 0.20×0.15×0.10
À0.364
3.10 to 33.00 5.37 to 29.77

1540
Helvetica Chimica Acta – Vol. 89 (2006)
g, 1.8 mmol): 0.55 g (82%) of 2. 1H-NMR (CD2Cl2, 298 K): 8.00 (dd, 3Jo,m =7.2, 4Jo,p =1.2, Ho); 7.80 (t, 3Jp,
3
3
3
m =8.2, Hp); 7.57 (m, Hm and HB); 7.12 (d, JA,B =7.2, HA); 6.94 (t, JC,B =3JC,D =7.0, HC); 6.74 (d, JD,
3
C =7.0, HD); 3.72 (sept., 3J=6.3, Me2
CH); 1.47 (d, J=6.3, Me2
A
Di-m-chlorobis{2-{1-[(2,6-diisopropylphenyl)imino-kN]-2-oxo-2-phenylethyl}phenyl-kC}dipalladium
(3). As described for 1, with Na2[PdCl4] (1 g, 3.4 mmol), MeOH (20 ml), and (2,6-iPr2C6H3ÀN=C(Ph)À
C(Ph)=O (1.4 g, 3.8 mmol, 2 d): 1.43 g (83%). 1H-NMR (CD2Cl2, 298 K): 7.86 (d, 3Jo,m =7.6, Ho); 7.65 (t,
3Jp,m =7.6, Hp); 7.47 (t, 3Jm,p =3Jm,o =7.6, Hm); 7.27 (t, 3Jp’,m’ =3Jp’,m’ =7.6, Hp’); 7.13 (m, HB, HA, HC, Hm’);
6.99 (dd, 3JD,C =6.7, 4JD,B =1.5, HD); 6.89 (m, Hm’’); 3.29 (m, Me2
3J=6.7, Me2
CH); 0.91 (br. d, Me2CH).
C
G
U
ACHTREUNG
1
solid was recovered by filtration, rinsed with cold MeOH, and dried i.v.: 245 mg (73%) of 4. H-NMR
3
3
3
(CD2Cl2, 230 K): 8.99 (d, J(6’,5’)=5.4, HÀC(6’)); 8.55 (d, J(6,5)=4.9, HÀC(6)); 8.50 (d, J(3,4)=4.7,
HÀC(3)); 8.32 (m, HÀC(4), HÀC(3’), HÀC(4’)); 8.04 (br. d, Ho); 7.84 (m, HÀC(5), Hp, HÀC(5’));
3
3
3
7.62 (m, Hm); 7.28 (t, JB,C =3JB,A =7.6, HB); 7.16 (d, JA,B =7.6, HA); 7.12 (t, JC,B =3JC,D =7.6, HC); 6.94
(d, JD,C =7.6, HD); 3.68 (q, J=7.1, MeCH2); 1.40 (t, J=7.1, MeCH2). 13C{1H}-NMR (CD2Cl2, 230 K):
193.1 (s, Cd); 183.7 (s, Cc); 159.8 (s, Ca); 156.8 (s, C(2) or C(2’)); 155.1 (s, C(2) or C(2’)); 153.7 (s,
C(6’)); 149.9 (s, C(6)); 146.1 (s, Cb); 141.7 (s, C(4)); 141.7 (s, C(4’)); 137.1 (s, Cp); 134.3 (s, CA); 133.5
(s, Ci); 132.9 (s, CB); 130.2 (s, Cm, Co); 128.9 (s, CD); 128.5 (s, C(5’)); 128.2 (s, C(5)); 126.4 (s, CC);
124.4 (s, C(3)); 124.1 (s, C(3’)); 50.7 (s, MeCH2); 15.4 (s, MeCH2). 19F-NMR (CD2Cl2, 230 K): À73.17
3
3
3
(d, J(F,P)=712, [PF6]À). Anal. calc. for C26H22F6N3OPPd (643.86): C 48.50, H 3.44, N 6.53; found: C
1
48.52, H 3.46, N 6.51.
(2,2’-Bipyridine-kN2,kN2’){2-[1-isopropylimino-kN)-2-oxo-2-phenylethyl]phenyl-kC}palladium(1+)
Hexafluorophosphate(1À) (5). As described for 4, with 2 (200 mg, 0.25 mmol), MeOH (10 ml), 2,2’-bipyr-
idine (85 mg, 0.54 mmol), and NH4[PF6] (176 mg, 1.08 mmol): 192 mg (75%) of 5. 1H-NMR (CD2Cl2, 298
K): 9.04 (d, 3J(6’,5’)=3J(6,5)=5.1, HÀC(6’), HÀC(6)); 8.41 (d, 3J(3,4)=3J(3’,4’)=7.8, HÀC(3), HÀ
C(3’)); 8.35 (t, 3J(4,3)=3J(4’,3’)=7.8, HÀC(4), HÀC(4’)); 8.09 (d, 3Jo,m =7.2, Ho); 7.83 (m, HÀC(5),
3
3
4
Hp, HÀC(5’)); 7.67 (t, Jm,p =7.7, Hm); 7.31 (dt, JB,A =3JB,C =7.2, JB,D =1.5, HB); 7.14 (m, HA, HC); 6.92
3
4
3
3
3
(dd, JD,C =7.2, JD,B =1.6, HD); 4.08 (sept., J=6.8, Me2
N
G
Me2
CH). 13C{1H}-NMR (CD2Cl2, 298 K): 192.9 (s, Cd); 182.6 (s, Cc); 159.0 (s, Ca); 156.1 (br., C(2),
G
C(2’)); 153.0 (br., C(6), C(6’)); 146.5 (s, Cb); 141.5 (s, C(4)); 136.6 (s, Cp); 134.6 (s, CA); 134.0 (s, Ci);
132.6 (s, CB); 130.09 (s, Co); 130.05 (s, Cm); 128.9 (s, CD); 127.9 (s, C(5), C(5’)); 126.5 (s, CC); 124.3 (s,
C(3), C(3’)); 58.3 (s, Me2CH); 22.9 (s, Me2CH); 22.0 (s, Me2CH). Anal. calc. for C27H24F6N3OPPd
(657.88): C 49.29, H 3.68, N 6.39; found: C 49.40, H 3.77, N 6.54.
(2,2’-Bipyridine-kN2,kN2’){2-{1-[(2,6-diisopropylphenyl)imino-kN]-2-oxo-2-phenylethyl}phenyl-
kC}palladium(1+) Tetrafluoroborate(1À) (6). Complex 3 (300 mg, 0.30 mmol) and 2,2’-bipyridine (109
mg, 0.70 mmol) were dissolved in freshly dist. CH2Cl2 (10 ml). After the initial suspension was trans-
formed into a soln., Ag[BF4] (116 mg, 0.60 mmol) was added, and the soln. was stirred for 30 min. The
precipitated AgCl was removed by filtration and the volume of the soln. was reduced to ca. 2 ml. Addi-
tion of hexane caused the precipitation of the product, which was recovered by filtration, rinsed with cold
1
hexane and dried i.v.: 289 mg (67%) of 6. H-NMR (CD2Cl2, 217 K; for numbering see Fig. 3): 9.07 (d,
3J(6’,5’)=5.6, HÀC(6’)); 8.40 (m, HÀC(4’), HÀC(3’), HÀC(3)); 8.10 (ddd, 3J(4,3)=3J(4,5)=7.6, 4J(4,
6)=1.4, HÀC(4)); 7.99 (d, 3Jo,m =7.6, Ho); 7.90 (ddd, 3J(5’,4’)=3J(5’,6’)=3J(6’,5’)=5.6, 3J(5’,3’)=1.4,
HÀC(5’)); 7.76 (t, 3Jp,m =7.2, Hp); 7.57 (dd, 3Jm,p =7.2, 3Jm,o =3Jo,m =7.6, Hm); 7.51 (ddd, 3JB,A =3JB,
4
3
3
3
C =8.0, JB,D =1.6, HB); 7.47 (dd, Jp’,mu =3Jp’,md =7.6, Hp’); 7.38 (d, JA,B =8.0, HA); 7.35 (dd, Jmd,p’ =7.6,
4Jmd,mu =0.8, Hmd); 7.27 (dd, 3JC,D =3JC,B =7.6, HC); 7.21 (dd, 3JD,C =7.6, 4JD,B =1.6, HD); 7.14 (m, HÀ
3
3
3
C(5), Hmu); 5.7 (d, J(6,5)=5.2, HÀC(6)); 3.36 (sept., J=6.4, CHu); 3.16 (sept., J=6.4, CHd); 1.36 (d,
3J=6.4, Medb); 0.98 (d, 3J=6.4, Meuf); 0.95 (d, 3J=6.4, Medf); 0.34 (d, 3J=6.4, Meub). 13C{1H}-NMR
(CD2Cl2, 217 K; for numbering, see Fig. 3): 191.0 (s, Cd); 185.6 (s, Cc); 161.0 (s, Ca); 156.9 (s, C(2’));
155.1 (s, C(2)); 153.6 (s, C(6’)); 149.3 (s, C(6)); 146.7 (s, Cb); 143.3 (s, Cod); 142.2 (s, C(4’)); 141.6 (s,
C(4)); 140.8 (s, Cou); 140.2 (s, Ci’); 136.7 (s, Cp); 134.9 (s, CA); 134.0 (s, CB); 133.4 (s, Ci); 130.5 (s, Co,

Helvetica Chimica Acta – Vol. 89 (2006)
1541
CD); 130.1 (s, Cp’); 130.0 (s, Cm); 128.4 (s, C(5’)); 126.9 (s, CC); 126.6 (s, C(5)); 125.6 (s, Cmu); 125.3 (s, Cmd);
124.4 (s, C(3’)); 123.6 (s, C(3)); 29.1 (s, CHd); 28.7 (s, CHu); 24.8 (s, Meuf); 24.6 (s, Medf); 22.7 (s, Meub);
22.5 (s, Medb). 19F-NMR (CD2Cl2, 217 K): À152.49 (s, [10BF4]À); À152.54 (s, [11BF4]À). Anal. calc. for
C36H34BF4N3OPd · 0.5 MeOH (733.92): C 59.73, H 4.94, N 5.73; found: C 59.71, H 4.97, N 5.77.
{N,N’-(1,2-Dimethylethane-1,2-diylidene)bis[2,6-dimethylbenzenamine-kN]}{2-[1-(ethylimino-kN)-
2-oxo-2-phenylethyl]phenyl-kC}palladium(1+) Tetrafluoroborate(1À) (7). As described for 6, with 1 (150
mg, 0.20 mmol), (2,6-Me2C6H3)N=C(Me)ÀC(Me)=N(2,6-Me2C6H3) (87.3 mg, 0.40 mmol), CH2Cl2 (5
ml), and Ag[BF4] (77.3 mg, 0.40 mmol). From ca. 1 ml, addition of hexane caused the precipitation of
1
3
the product: 189 mg (73%) of 7. H-NMR (CD2Cl2, 230 K): 7.88 (br., Ho); 7.77 (t, Jp,m =7.6, Hp); 7.59
3
3
(t, Jm,p =3Jm,o =7.6, Hm); 7.38 (t, J(8,7)=3J(8,7’)=7.4, HÀC(8)); 7.31 (m, HÀC(7), HÀC(7’)); 7.20 (m,
HÀC(3), HÀC(3’), HÀC(4)); 6.87 (dt, JC,B =3JC,D =7.4, JC,A =0.6, HC); 6.72 (dd, JD,C =7.4, JD,B =1.3,
HD); 6.69 (dt, 3JB,C =3JB,A =7.4, 4JB,D =1.3, HB); 5.10 (d, 3JA,B =8.1, HA); 2.49 (m, MeCH2); 2.46 (s,
Me(14)); 2.39 (s, Me(11) or Me(12)); 2.35 (s, Me(13)); 2.34 (s, Me(15)); 2.33 (s, Me(12) or Me(11));
3
4
3
4
2.31 (s, Me(16)); 2.07 (m, MeCH2); 0.76 (t, J=6.9, MeCH2). 13C{1H}-NMR (CD2Cl2, 230 K): 192.9 (s,
3
Cd); 184.3 (s, Cc); 182.2 (s, C(9) or C(10)); 178.3 (s, C(10) or C(9)); 154.6 (s, Ca); 146.8 (s, Cb); 143.93
(s, C(1)); 143.88 (s, C(5)); 136.9 (s, Cp); 133.3 (s, Ci); 131.0 (s, C(6)); 130.9 (s, CB); 130.5 (s, C(6’));
130.4 (s, CA); 130.2 (s, Cm); 129.8 (s, C(7) or C(3)); 129.7 (s, C(3) or C(7)); 129.6 (s, C(3’) and C(7’));
129.3 (s, C(2) or C(2’)); 129.0 (s, CD); 128.9 (s, C(8)); 128.4 (s, C(4)); 126.5 (s, CC); 49.3 (s, MeCH2);
21.3 (s, C(11) or C(12)); 20.3 (s, C(12) or C(11)); 18.8 (s, C(14)); 18.76 (s, C(13), C(15)); 18.54 (s,
C(16)); 16.2 (s, MeCH2). 19F-NMR (CD2Cl2, 230 K): À151.36 (s, [10BF4]À); À151.54 (s, [11BF4]À). Anal.
calc. for C36H38BF4N3OPd (721.9310): C 59.89, H 5.31, N 5.82; found: C 59.77, H 5.25, N 5.96.
{N,N’-(Acenaphthylene-1,2-diylidene)bis[2,6-dimethylbenzenamine-kN]}{2-[1-(ethylimino-kN)-2-
oxo-2-phenylethyl]phenyl-kC}palladium(1+) Tetrafluoroborate(1À) (8). As described for 6, with 1 (150
mg, 0.20 mmol), (2,6-Me2C6H3)N=C(R)ÀC(R)=N(2,6-Me2C6H3) (RÀR=naphthalene-1,8-diyl; 161
mg, 0.42 mmol), CH2Cl2 (5 ml), and Ag[BF4] (77.6 mg, 0.40 mmol). From ca. 1 ml, addition of hexane
1
3
caused the precipitation of the product: 235 mg (67%) of 8. H-NMR (CD2Cl2, 230 K): 8.30 (d, J(25,
G
25)=8.1, HÀC(25)); 8.27 (3J(22,23)=8.0, HÀC(23)); 7.95 (br., Ho); 7.80 (tt, Jp,m =7.5, Jp,o =1.3, Hp);
7.61 (m, Hm, HÀC(8), HÀC(26), HÀC(22)); 7.49 (d, 3J(7,8)=3J(7’,8)=7.9, HÀC(7), HÀC(7’)); 7.38
(m, HÀC(4), HÀC(3’), HÀC(3)); 6.97 (t, 3JC,B =3JC,D =7.6, HC); 6.79 (m, HD, HB); 6.58 (d, 3J(21,
3
4
22)=6.9, HÀC(21)); 6.52 (d, J(26,27)=6.9, HÀC(27)); 5.45 (dd, 3JA,B =7.9, JA,C =0.6, HA); 2.84 (m,
MeCH2); 2.64 (m, MeCH2); 2.44 (s, Me(14)); 2.37 (s, Me(13)); 2.33 (s, Me(15)); 2.32 (s, Me(16)); 0.78
(t, 3J=7.0, MeCH2). 13C{1H}-NMR (CD2Cl2, 230 K): 192.8 (s, Cd); 184.5 (s, Cc); 176.2 (s, C(10) or
C(9)); 172.5 (s, C(10) or C(9)); 152.3 (s, Ca); 147.0 (s, Cb); 146.8 (s, C(28)); 143.7 (s, C(1)); 143.1 (s,
C(5)); 137.0 (s, Cp); 134.2 (s, C(25)); 133.7 (s, C(23)); 133.4 (s, Ci); 131.43 (s, C(24)); 131.37 (s, CB);
130.84 (s, C(6)); 130.77 (s, C(6’)); 130.56 (s, C(7), C(7’)); 130.42 (s, C(3), C(3’)); 130.2 (s, Cm and C(8)
or C(26) or C(22)); 130.12 (s, C(8) or C(26) or C(22)); 130.02 (s, C(8) or C(26) or C(22)); 129.39 (s,
CD); 129.21 (s, C(4)); 129.09 (s, C(2)); 129.01 (s, C(2’)); 128.98 (s, CA); 126.88 (s, CC); 126.78 (s,
C(27)); 126.34 (s, C(21)); 125.55 (s, C(11) or C(12)); 125.18 (s, C(12) or C(11)); 49.8 (s, MeCH2);
18.76 (s, C(14)); 18.75 (s, C(13)); 18.65 (s, C(15)); 18.59 (s, C(16)); 15.76 (s, MeCH2). 19F-NMR
(CD2Cl2, 230 K): À153.07 (s, [10BF4]À); À153.14 (s, [11BF4]À). Anal. calc. for C44H38BF4N3OPd (818.02):
C 64.60, H 4.68, N 5.14; found: C 64.72, H 4.72, N 5.19.
3
4
{N,N’-(1,2-Dimethylethane-1,2-diylidene)bis[2,6-diisopropylbenzenamine-kN]}{2-[1-(ethylimino-
kN)-2-oxo-2-phenylethyl]phenyl-kC}palladium(1+) Tetrafluoroborate(1À) (9). As described for 6, with 1
(100 mg, 0.13 mmol), (2,6-iPr2C6H3)N=C(Me)ÀC(Me)=N(2,6-iPr2C6H3) (112 mg, 0.27 mmol), CH2Cl2 (5
ml), and Ag[BF4] (53 mg, 0.27 mmol). From ca. 1 ml, addition of hexane caused the precipitation of the
1
3
product: 142.8 mg (63%) of 9. H-NMR (CD2Cl2, 230 K): 7.87 (br., Ho); 7.77 (t, Jp,m =7.5, Hp); 7.58 (t,
A
3Jm,p =3Jm,o =3Jp,m =7.5, Hm); 7.54 (t, 3J(4,3)=3J(4,3’)=7.4, HÀC(8)); 7.44 (dd, 3J(3,4)=7.4,
4J(3,3’)=0.97, HÀC(7)); 7.34 (m, HÀC(3), HÀC(3’), HÀC(4), HÀC(7’)); 6.85 (dt, 3JC,D =3JC,B =7.4,
4JC,A =0.68, HC); 6.69 (dd, JD,C =7.4, JD,B =1.5, HD); 6.65 (dt, JB,A =3JB,C =7.4, JB,D =1.5, HB); 5.06 (d,
3
4
3
4
3JA,B =7.4, HA); 3.34 (sept., J(13,17)=6.7, HÀC(13)); 3.14 (m, HÀC(14), HÀC(16)); 3.04 (sept., J(15,
3
3
19)=6.9, HÀC(15)); 2.66 (m, 3J=7.1, MeCH2); 2.45 (s, Me(12)); 2.42 (s, Me(11)); 2.27 (m, 3J=7.1,
3
MeCH2); 1.45 (d, J(17f,13)=6.7, Me(17f)); 1.27 (m, Me(18f), Me(18b), Me(20b), Me(19b), Me(19f));
1.15 (d, 3J(17b,13)=6.7, Me(17b)); 0.86 (d, 3J(20f,16)=6.7, Me(20f)); 0.58 (t, 3J=7.1, MeCH2).

1542
Helvetica Chimica Acta – Vol. 89 (2006)
13C{1H}-NMR (CD2Cl2, 230 K): 192.6 (s, Cd); 185.5 (s, Cc); 181.7 (s, C(10)); 177.9 (s, C(9)); 156.0 (s, Ca);
146.7 (s, Cb); 142.1, 141.8, 140.35, 139.34, 138.9, 138.7 (s, C(1), C(2), C(2’), C(5), C(6), C(6’)); 136.9 (s, Cp);
133.1 (s, Ci); 132.3 (s, CA); 130.5 (s, CB); 130.1 (s, Cm); 129.8 (s, C(8)); 129.3 (s, C(4)); 128.8 (s, CD); 126.4
(s, CC); 125.7, 125.5 (s, C(3), C(3’), C(7’)); 125.2 (s, C(7)); 49.5 (s, MeCH2); 29.9 (s, C(13)); 29.5 (s, C(15));
29.3 (s, C(14)); 28.9 (s, C(16)); 24.4 (s, C(17b)); 23.3 (s, C(17f)); 24.3, 23.9, 23.8, 23.4, 22.9 (s, C(18b),
C(18f), C(19b), C(19f), C(20b)); 22.7 (s, C(12)); 22.6 (s, C(20f)); 22.3 (s, C(11)); 16.3 (s, MeCH2). 19F-
NMR (CD2 Cl2, 230 K): À151.36 (s, [10BF4]À); À151.42 (s, [11BF4]À). Anal. calc. for C44H54BF4N3OPd
(834.14): C 63.35, H 6.53, N 5.04; found: C 63.22, H 6.41, N 5.01.
{N,N’-(Acenaphthylene-1,2-diylidene)bis[2,6-diisopropylbenzenamine-kN]}{2-[1-(ethylimino-kN)-2-
oxo-2-phenylethyl]phenyl-kC}palladium(1+) Tetrafluoroborate(1À) (10). As described for 6, with 1 (150
mg, 0.20 mmol), (2,6-iPr2C6H3)N=C(R)ÀC(R)=N(2,6-iPr2C6H3) (RÀR=naphthalene-1,8-diyl; 220 mg,
0.44 mmol), CH2Cl2 (5 ml), and Ag[BF4] (78 mg, 0.40 mmol). From ca. 1 ml, addition of hexane caused
the precipitation of the product. Further purification by crystallization from CH2Cl2/Et2O yielded 10
A
1
(371 mg, 94%). H-NMR (CD2Cl2, 230 K): 8.31 (d, 3J(25,26)=8.3, HÀC(25)); 8.28 (d, 3J(23,22)=8.2,
HÀC(23)); 7.95 (br., Ho); 7.82 (t, 3Jp,m =7.5, Hp); 7.78 (t, 3J(8,7)=3J(8,7’)=7.5, HÀC(8)); 7.63 (t,
3Jm,p =3Jm,o =7.5, Hm); 7.61 (t, 3J(26,25)=3J(26,27)=8.3, HÀC(26)); 7.59 (t, 3J(22,23)=3J(22,21)=8.2,
HÀC(22)); 7.59 (d, overlapped by HÀC(22) and HÀC(26), HÀC(7)); 7.57 (t, overlapped by HÀC(22),
HÀC(4)); 7.55 (d, overlapped by HÀC(4) and HÀC(22), HÀC(7’)); 7.49 (d, 3J(3,4)=7.7, HÀC(3));
3
3
3
4
7.47 (d, J(3’,4)=7.7, HÀC(3’)); 6.96 (t, JC,B =3JC,D =7.2, HC); 6.82 (dd, JD,C =7.2, JD,B =1.5, HD); 6.79
(dt, JB,C =3JB,A =8.1, JB,D =1.5, HB); 5.57 (d, JA,B =8.1, HA); 3.33 (m, HÀC(14), HÀC(13), HÀC(15),
3
4
3
HÀC(16)); 2.95 (m, MeCH2); 2.77 (m, MeCH2); 1.47 (d, 3J(17,13)=6.7, HÀC(17f)); 1.41 (d, 3J(18,
3
3
14)=6.7, HÀC(18f)); 1.27 (d, J(19,18)=6.7, HÀC(19f)); 1.06 (d, J(20,16)=6.7, HÀC(20f)); 1.03 (d,
3J(18,14)=6.7, HÀC(18b)); 1.00 (d, 3J(19,15)=6.7, HÀC(19b)); 0.97 (d, 3J(20,16)=6.7, HÀC(20b));
3
3
0.87 (d, J(17,13)=6.7, HÀC(17b)); 0.75 (t, J=7.2, MeCH2). 13C{1H}-NMR (CD2Cl2, 230 K): 192.5 (s,
Cd); 185.2 (s, Cc); 176.1 (s, C(10)); 172.9 (s, C(9)); 153.7 (s, Ca); 146.8 (s, Cb); 146.6 (s, C(28)); 142.4 (s,
C(1)); 141.2 (s, C(5) or C(2) or C(2’)); 140.5 (s, C(6) or C(6’)); 140.2 (s, C(6) or C(6’)); 138.8 (s, C(5)
or C(2) or C(2’)); 138.7 (C(5) or C(2) or C(2’)); 137.1 (s, Cp); 134.3 (s, C(25)); 133.8 (s, C(23)); 133.2
(s, Ci or C(12) or C(11)); 131.7 (s, C(24)); 131.0 (s, CB); 130.7 (s, C(8)); 130.6 (s, CA); 130.2 (s, Cm);
129.95 (s, C(7’) or C(7) or C(4)); 129.91 (s, C(7’) or C(7) or C(4)); 129.88 (s, C(7’) or C(7) or C(4));
129.3 (s, CD); 127 5 (s, C(27)); 127.2 (s, C(21)); 126.9 (s, CC); 126.22 (s, C(22) or C(27)); 126.19 (s,
C(3)); 126.15 (s, C(22) or C(27)); 125.90 (s , Ci or C(11) or C(12)); 125.87 (s, C(3’)); 125.76 (s, Ci or
C(11) or C(12)); 49.3 (s, MeCH2); 30.2 (s, C(13)); 29.8 (s, C(14)); 29.7 (s, C(15)); 29.6 (s, C(16)); 24.8
(s, C(17b)); 24.4 (s, C(18b)); 24.3 (s, C(19b)); 23.8 (s, C(20b)); 23.4 (s, C(17f)); 23.3 (s, C(18f)); 22.9
(s, C(19f)); 22.9 (s, C(20f)); 16.2 (s, MeCH2). 19F-NMR (CD2Cl2, 230 K): À153.01 (s, [10BF4]À);
À153.06 (s, [11BF4]À). Anal. calc. for C52H54BF4N3OPd (930.23): C 67.14, H 5.85, N 4.52; found: C
67.28, H 5.93, N 4.42.
{[1-(Benzoyl-kO)-2,3-dihydro-2-isopropyl-3-oxo-1H-isoindol]carbonyl-kC}(2,2’-bipyridine-kN2,
kN2’)palladium(1+) Hexafluorophosphate(1À) (14). A 5-mm NMR tube equipped with a PTFE-J. Young
valve was charged with 5 (ca. 10 mg) and then connected to the high-vacuum line and evacuated to ca.
10À5 Torr. CD2Cl2 (ca. 0.5 ml) was condensed into the tube by using a liq. N2 bath. The tube was allowed
to reach r.t. in order to completely dissolve 5, the soln. was frozen again and evacuated to ca. 10À5 Torr.
The tube was filled with CO while the soln. was frozen, and then allowed to slowly reach r.t. by using an
EtOH/liq. N2 bath. A small amount of a light-brown precipitate was observed. Compound 14 (>90% of
the mixture) was identified by NMR spectroscopy. It was not possible to experimentally discriminate
between the two inequivalent pyridine rings of the coordinated bpy ligand; the resonance at higher fre-
quency was assigned to HÀC(6’) in agreement with a similar observation in [Ru(acetyl)] complexes with
1
3
4
5
pyrazolyl ligands [3b]. H-NMR (CD2Cl2, 298 K): 9.16 (ddd, J(6’,5’)=5.2, J(6’,4’)=1.6, J(6’,3’)=0.8,
HÀC(6’)); 9.07 (ddd, 3J(6,5)=5.6, 4J(6,4)=1.6, 5J(6,3)=0.7, HÀC(6)); 8.42 (m, HÀC(3), HÀC(3’));
8.37 (dt, 3J(4’,5’)ꢀ J(4’,3’)=7.5, 4J(4’,6’)=1.6, HÀC(4’)); 8.30 (dt, 3J(4,5)ꢀ J(4,3)=7.7, 4J(4,6)=1.6,
3
3
3
4
5
3
3
4
HÀC(4)); 8.05 (ddd, JA,B =7.6, JA,C =1.3, JA,D =0.8, HA); 7.96 (ddd, J(5’,4’)=7.7, J(5’,6’)=5.2, J(5’,
3’)=1.3, HÀC(5’)); 7.94 (dd, Jo,m =8.6, Jo,p =1.3, Ho); 7.91 (dt, JD,C =7.6, JD,B +5JD,A =1.8, HD); 7.85
3
4
3
4
(tt, 3Jp,m =7.5, 4Jp,o =1.3, Hp); 7.75 (ddd, 3J(5,4)=7.6, 3J(5,6)=5.6, 4J(5,3)=1.4, HÀC(5)); 7.72 (dt,
3JB,A ꢀ JB,C =7.5, 4JB,D =1.0, HB); 7.65 (dt, JC,B ꢀ JC,D =7.6, 4JC,A =1.3, HC); 7.57 (dd, 3Jm,o =8.6,
3
3
3

Helvetica Chimica Acta – Vol. 89 (2006)
1543
3Jm,p =7.5, Hm); 3.98 (sept., 3J=6.7, Me2CH); 1.30, 1.20 (d, 3J=6.7, Me2CH). 13C{1H}-NMR (CD2Cl2, 298
A
ACHTREUNG
K): 209.9 (s, Cd); 206.0 (s, Cf); 168.6 (s, Ce); 156.3 (s, C(2)); 153.5 (s, C(2’)); 150.5 (s, C(6’)); 149.9 (s, C(6));
142.3 (s, C(4’)); 142.0 (s, C(4)); 139.2 (s, Cb); 138.9 (s, Cp); 133.7 (s, CC); 131.8 (s, Co); 131.6 (s, CB); 131.0 (s,
Ca); 130.3 (s, Cm); 129.9 (s, Ci); 128.2 (s, C(5’)); 127.6 (s, C(5)); 125.9 (s, CA); 124.1, 123.5 (s, C(3), C(3’));
122.0 (s, CD); 100.7 (s, Cc); 49.1 (s, Me2CH); 20.7, 20.6 (s, Me2
A
1J(F,P)=710, [PF6]À).
[1-(Benzoyl-kO)-2,3-dihydro-2-isopropyl-3-oxo-1H-isoindol-1-yl-kC](2,2’-bipyridine-kN2,kN2’)-
palladium(1+) Hexafluorophosphate(1À) (16). A dil. soln. of 14 in a 5-mm NMR tube equipped with a
PTFE-J. Young valve and connected to the high-vacuum line, was decarbonylated by means of one
freeze-pump-thaw degassing cycle. The obtained product mixture contained 16 (ca. 90%), residual com-
plex 14, and a very small amount of other minor unidentified by-products. 1H-NMR (CD2Cl2, 298 K): 8.86
3
4
3
(dt, J(6,5)=5.4, J(6,4)+5J(6,3)=2.5, HÀC(6)); 8.34 (m, HÀC(4), HÀC(3)); 8.24 (ddd, J(3’,4’)=8.1,
4J(3’,5’)=1.3, 5J(3’,6’)=0.7, HÀC(3’)); 8.15 (m, HD, HÀC(4’)); 8.05 (ddd, 3JA,B =5.7, 4JA,C =3.2,
5JA,D =0.7, HA); 7.86 (m, HÀC(5), Hp); 7.80 (dd, Jo,m =8.3, Jo,p =1.2, Ho); 7.66 (m, ABXY, HC, HB);
3
4
7.58 (dd, 3Jm,o =8.3, 4Jm,p =7.4, Hm); 7.45 (ddd, 3J(5’,4’)=7.6, 3J(5’,6’)=5.6, 4J(5’,3’)=1.4, HÀC(5’));
3
4
4
3
6.88 (ddd, J(6’,5’)=5.6, J(6’,4’)=1.5, J(6’,3’)=0.7, HÀC(6’)); 4.14 (sept., J=6.7, Me2
CH); 1.50, 1.36
3
(d, J=6.7, Me2
A
N
(s, C(2)); 150.3 (s, C(6)); 148.8 (s, C(6’)); 143.1 (s, Cb); 142.00 (s, C(4)); 141.98 (s, C(4’)); 138.9 (s, Cp);
133.3 (s, CC); 131.15 (s, Ci); 130.5 (s, Co); 130.0 (s, Cm); 129.8 (s, Ca); 128.8 (s, CB); 128.4 (s, C(5));
127.9 (s, C(5’)); 125.2 (s, CA); 124.2 (s, C(3)); 123.7 (s, C(3’)); 121.5 (s, CD); 50.0 (s, Me2CH); 45.7 (s,
Cc); 20.9, 20.8 (s, Me2
A
3-Benzoyl-2-ethyl-2,3-dihydro-1H-isoindol-1-one (11) and 3-Benzoyl-2,3-dihydro-2-isopropyl-1H-
isoindol-1-one (12). An excess of H2O was added to a soln. of either 16 or 14 in a 5-mm NMR tube.
Over a period of hours (depending on the H2O concentration), the quant. formation of 12 was observed,
together with the precipitation of an amorphous dark solid. Complex 11 was obtained similarly by start-
ing from 13 or 15. Alternatively, 11 and 12 were formed from 4 or 5, resp., by performing the carbonyla-
tion reaction in wet CD2Cl2 or CH2Cl2.
Data of 11: 1H-NMR (CD2Cl2, 298 K): 8.04 (dd, 3Jo,m =8.4, 4Jo,p =1.3, Ho); 7.86 (ddd, 3JA,B =7.5,
4JA,C =1.3, 5JA,D =0.8, HA); 7.74 (tt, 3Jp,m =7.5, 4Jp,o =1.3, Hp); 7.61 (t, Jm,o ꢀ Jm,o =7.9, Hm); 7.52 (td,
3
3JB,C ꢀ JB,A =7.5, 4JB,D =1.0, HB); 7.46 (td, JC,D ꢀ JC,B =7.5, 4JC,A =1.3, HC); 7.25 (dd, 3JD,C =7.5,
4JD,B =1.0, HD); 6.18 (s, Hc); 4.08 (m, MeCH2); 3.21 (m, MeCH2); 1.25, (t, 3J=7.3, MeCH2). 13C{1H}-
NMR (CD2Cl2, 298 K): 194.1 (s, Cd); 168.8 (s, Ce); 140.0 (s, Cb); 135.9 (s, Ci); 134.6 (s, Cp); 132.8 (s,
Ca); 131.9 (s, CC); 129.6 (s, Cm); 129.4 (s, CB); 129.2 (s, Co); 124.3 (s, CA); 123.0 (s, CD); 65.4 (s, Cc);
36.7 (s, MeCH2); 13.6 (s, MeCH2).
Data of 12: 1H-NMR (CD2Cl2, 298 K): 7.97 (dd, 3Jo,m =8.4, 4Jo,p =1.3, Ho); 7.88 (ddd, 3JA,B =7.5,
4JA,C =1.3, 5JA,D =0.8, HA); 7.71 (tt, 3Jp,m =7.5, 4Jp,o =1.3, Hp); 7.57 (t, Jm,o ꢀ Jm,o =7.9, Hm); 7.53 (td,
3
3JB,C ꢀ JB,A =7.5, 4JB,D =1.0, HB); 7.48 (td, JC,D ꢀ JC,B =7.5, 4JC,A =1.3, HC); 7.22 (dd, 3JD,C =7.5,
4JD,B =1.0, HD); 6.12 (s, Hc); 4.42 (sept., J=6.8, Me2
(CD
(s, CC); 129.5 (s, Cm); 129.4 (s, CB); 129.2 (s, Co); 124.1 (s, CA); 122.7 (s, CD); 65.0 (s, Cc); 46.0 (s,
Me2CH); 21.1, 20.3 (s, Me2CH).
2Cl2, 298 K): 195.4 (s, Cd); 169.3 (s, Ce); 140.8 (s, Cb); 135.7 (s, Ci); 134.6 (s, Cp); 133.2 (s, Ca); 132.0
AHCTREUNG
(2,2’-Bipyridine-kN,kN2’){1-(ethylamino-kN)-1-{2-[(1E)-2-(4-methylphenyl)ethenyl]phenyl}-2-oxo-
2-phenylethyl-kC}palladium(1+) Hexafluorophosphate(1À) (17) and (2,2’-Bipyridine-kN,kN2’){1-(iso-
propylamino-kN)-1-{2-[(1E)-2-(4-methylphenyl)ethenyl]phenyl}-2-oxo-2-phenylethyl-kC}palladium(1+)
Hexafluorophosphate(1À) (18). To a soln. of 5 (100 mg, 0.15 mmol) in CH2Cl2 (5 ml), p-methylstyrene (3
ml; Pd/p-methylstyrene mol ratio 1:150) was added. Within 16 h, the initially yellow soln. became dark
yellow/orange, while a small amount of dark precipitate was formed. The soln. was filtered, and the vol-
ume was reduced to ca. 3.5 ml, and hexane was then added. The precipitated solid was collected by fil-
tration and washed several times with Et
A
(90%). Complex 17 was obtained similarly from 4.
3
4
Data of 18: 1H-NMR (major isomer, ca. 85%; CD2Cl2, 298 K): 8.82 (ddd, J(6,5)=5.2, J(6,4)=1.6,
5J(6,3)=0.7, HÀC(6)); 8.32 (ddd, 3JD,C =7.8, 4JD,B = 1.9, 5JD,A =0.4, HD); 8.28 (ddd, 3J(3,4)=8.0, 4J(3,
5)=1.3, 5J(3,6)=0.7, HÀC(3)); 8.26 (ddd, 3J(3’,4’)=7.9, 4J(3’,5’)=1.3, 5J(3’,6’)=0.7, HÀC(3)); 8.20

1544
Helvetica Chimica Acta – Vol. 89 (2006)
(ddd, 3J(4,5)=9.2, 4J(4,3)=8.0, 5J(4,6)=1.6, HÀC(4)); 8.10 (ddd, 3J(4’,5’)=9.2, 4J(4’,3’)=7.9, 5J(4’,
6’)=1.6, HÀC(4’)); 7.84 (dd, 3JA,B =8.0, 4JA,C =1.3, HA); 7.78 (ddd, 3J(6’,5’)=5.4, 4J(6’,4’)=1.6, 5J(6’,
3
3’)=0.7, HÀC(6’)); 7.69 (ddd, 3J(5,4)=9.2, 3J(5,6)=5.2, 4J(5,3)=1.3, HÀC(5)); 7.67 (dt, JB,A
ꢀ
3JB,C =8.0, 4JB,D =1.9, HB); 7.57 (dd, 3Jo,m =8.5, 3Jo,p =1.3, Ho); 7.53 (tt, 3Jp,m =7.5, 4Jp,o =1.3, Hp); 7.49
3
3
(dt, JC,B ꢀ JC,D =7.9, 4JC,A =1.3, HC); 7.30 (m, HÀC(11), Hm); 7.24 (ddd, 3J(5’,4’)=9.2, 3J(5’,6’)=5.4,
3
4J(5’,3’)=1.3, HÀC(5’)); 7.18 (d, J(12,11)=8.6, HÀC(12)); 7.05 (s, HÀC(8), HÀC(9); in CDCl3 at a
3
3
lower concentration, AB, J(8,9)= 16); 6.23 (br. d, J=6.4, Me2
A
G
Me(14)); 1.47, 1.39 (d, 3J=6.5, Me2CHNH). 13C{1H}-NMR (CD2
Cl2, 298 K): 188.4 (s, Cd); 155.4 (s,
N
C(2’)); 153.9 (s, C(2’)); 152.9 (s, C(6)); 152.6 (s, C(6’)); 141.1 (s, C(4)); 140.9 (s, C(4’)); 139.2 (s,
C(13)); 138.3 (s, Ca); 135.95 (s, CD); 135.88 (s, Ci); 134.0 (s, C(10)); 133.9 (s, C(8) or C(9)); 133.7 (s,
Cp); 131.5 (s, CB); 130.6 (s, Cb); 129.9 (s, C(12)); 129.3 (s, Co); 129.0 (s, Cm, CC); 127.8 (s, C(5)); 127.4
(s, C(5’)); 126.91 (s, C(11)); 126.87 (s, CA); 123.51 (s, C(3’)); 123.43 (s, C(9) or C(8)); 123.38 (s, C(3));
76.6 (s, Cc); 50.0 (s, Me2CHNH); 26.1, 22.8 (s, Me2CHNH); 21.3 (s, C(14)). 19F-NMR (CD2Cl2, 298 K):
1
À73.7 (d, J(F,P)=710, [PF6]À).
2-{2-[(1E)-2-(4-Methylphenyl)ethenyl]phenyl}-2-(isopropylimino)-1-phenylethan-1-one (19). A 5-
mm NMR tube equipped with a PTFE-J. Young valve was charged with 18 (20 mg), connected to the
high-vacuum line, and evacuated to ca. 10À5 Torr. CD2Cl2 (ca. 0.5 ml) was condensed into the tube by
using a liq. N2 bath. The tube was allowed to reach r.t. to completely dissolve compound 18, the soln.
was frozen again and evacuated to ca. 10À5 Torr. The tube was filled with CO while the soln. was frozen,
and then allowed to slowly reach r.t. by using an EtOH/liq. N2 bath. A large amount of an amorphous
dark precipitate formed, and 19 (>95% of the mixture) was identified by NMR spectroscopy. 1H-
3
3
NMR (CD2Cl2, 298 K): 8.21 (dd, 3Jo,m =8.5, Jo,p =1.3, Ho); 7.82 (d, JA,B =8.0, HA); 7.67 (t, 3Jp,m =7.6,
3
3
3
3
4
3
3
Hp); 7.57 (t, Jo,m ꢀ Jm,p =7.8, Hm); 7.49 (dt, JB,A ꢀ JB,C =7.9, JB,D =1.4, HB); 7.38 (dt, JC,B ꢀ JC,D =7.7,
4JC,A =1.2, HC); 7.31 (d, J(12,11)=8.1, HÀC(11)); 7.21 (d, JC,D =8.0, HD); 7.16 (d, J(12,11)=8.1, HÀ
3
3
3
3
3
C(12)); 7.05 (AB, J(8,9)ꢀ16, HÀC(8), HÀC(9)); 3.66 (sept., J=6.5, Me2CHNH); 2.37 (s, HÀC(14));
A
1.21, (d, 3J=6.5, Me2CHNH). 13C{1H}-NMR (CD2Cl2, 298 K): 193.0 (s, Cd); 164.5 (s, Cc); 138.5 (s,
C(13)); 136.0 (s, Ci); 135.9 (s, Ca); 134.4 (s, C(10)); 134.2 (s, Cb); 133.6 (s, Cp); 131.5 (s, C(8) or C(9));
131.2 (s, Co); 129.7 (s, C(12)); 129.5 (s, CB); 128.7 (s, Cm); 128.2 (s, CD); 127.5 (CC); 126.8 (s, C(11));
125.5 (s, CA); 124.9 (s, C(9) or C(8)); 54.8 (s, Me2CHNH); 23.3 (s, Me2CHNH); 21.3 (s, Me(14)).
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Received January 30, 2006