Synthesis, characterization and catalytic activity in Heck-type reactions of orthometallated PdII and PtII complexes derived from (1R,2R)-1,2-diaminocyclohexane

Article abstract of DOI:10.1016/S0022-328X(02)01148-8

The chiral bis-imine orthometallated [Pd(OAc)(C₆H₂-4,5-(OMe)₂-2-CH-N-(1R,2R) -C₆H₁₀-N-CH-C₆H₃′,4′- (OMe)₂-κ-C,N,N)] 2 (abbreviated as [Pd(OAc)(L-κ-C,N,N)]), through C-H bond activation on only one of the aryl rings and N,N-coordination of the two iminiek N atoms. 2 reacts with an excess of LiC1 to give [Pd(C1)(L-κ-C,N,N)] 3. The reaction of 3 with AgClO₄ and neutral or amionic ligand L′ (1:1:1 molar ratio) affords [Pd{L-κ-C,N,N)(L′)](ClO₄) (L′= PPh₃ 4a, NCMe 5, pyridine 6, p-nitroaniline 7) or [Pd(1)(L-κ-C,N,N)] 8. Complex 4a reacts with wet CDC1₃ giving [Pd(C₆H₂-4.5-(OMe)₂ 2-CH=N-(1R,2R) (C₆H₁₀ NH₂-κ-C,N,N) (PPh₃)](ClO₄) 4b as a result of the hydrolysis of the C=N bond not involved in the orthometallated ring. The molecular structure of 4b-CH₂Cl₂ has been determined by X-ray diffraction methods. Cleavage of the Pd-N bond trans to the C_aryl atom can be accomplished by coordination of strongly chelating ligands, such as acetylacetonate (acac) or bis(diphenylphosphino)ethane (dppe), forming [Pd(acac-O,O′)(L-κ-C,N)] 9 and [Pd(L-κ-C,N)(dppen-P.P)](ClO₄) 12, while classical N,N′-chelating ligands such as 1.10-phenantroline (phen) or 2.2′-bipyridyl (bipy) behave as monodentate N-donor ligands yielding [Pd(L-κ-C,N,N)(κ¹-N-phen)] (ClO₄) 10 and [Pd(L-κ-C,N,N)(κ¹-N-bipy)]C1O₄) 11. Treatment of 1 with PtC1₂(DMSO)₂ (1:1 molar ratio) in refluxing 2-methoxyethanol gives Cl₂Pt[(NH₂)₂C₆H₁₀-H,N ′] 13a and [Pt{C1)(C₆H₂-4,5-(OMe)₂ 2-CH=N-(1R,2R)-C₆H₁₀-NH₂-κ-C,N,N)] 13b, while [Pt(C1)(L-κ-C,N,N)] 14 can be obtained by reaction of [Pt(μ-C1)(η³-2-Me-C₃H₄)]₂ with 1 in refluxing CHC1₃. Complexes 2 and 3 catalyzed the arylation of methyl acrylate giving good yields of the corresponding methyl cinnamates and TON up to 847 000. Complex 3 also catalyzes the hydroarylation of 2-norbornene, but with lower yields and without enantioselectivity.

Full text of DOI:10.1016/S0022-328X(02)01148-8

Journal of Organometallic Chemistry 650 (2002) 157–172
www.elsevier.com/locate/jorganchem
Synthesis, characterization and catalytic activity in Heck-type
reactions of orthometallated PdII and PtII complexes derived from
(1R,2R)-1,2-diaminocyclohexane
Judith Bravo a, Carlos Cativiela a, Rafael Navarro b,*, Esteban P. Urriolabeitia b,*
a Departamento de Qu´ımica Orga´nica, Instituto de Ciencia de Materiales de Arago´n,
Uni6ersidad de Zaragoza-Consejo Superior de In6estigaciones Cient´ıficas, E-50009 Zaragoza, Spain
b Departamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n,
Uni6ersidad de Zaragoza-Consejo Superior de In6estigaciones Cient´ıficas, E-50009 Zaragoza, Spain
Received 25 September 2001; accepted 5 December 2001
Abstract
The chiral bis-imine (1R,2R)-C6H10-[EꢀNꢁCHꢀC6H3ꢀ3,4-(OMe)2]2 1 (LH) reacts with [Pd(OAc)2] (1:1 molar ratio; OAc=ace-
tate) giving the orthometallated [Pd(OAc)(C6H2ꢀ4,5-(OMe)2ꢀ2-CHꢁN-(1R,2R)-C6H10ꢀNꢁCHꢀC6H3-3%,4%-(OMe)2-k-C,N,N)] 2
(abbreviated as [Pd(OAc)(L-k-C,N,N)]), through CꢀH bond activation on only one of the aryl rings and N,N-coordination of the
two iminic N atoms. 2 reacts with an excess of LiCl to give [Pd(Cl)(L-k-C,N,N)] 3. The reaction of 3 with AgClO4 and neutral
or anionic ligands L% (1:1:1 molar ratio) affords [Pd(L-k-C,N,N)(L%)](ClO4) (L%=PPh3 4a, NCMe 5, pyridine 6, p-nitroaniline 7)
or [Pd(I)(L-k-C,N,N)] 8. Complex 4a reacts with wet CDCl3 giving [Pd(C6H2ꢀ4,5-(OMe)2ꢀ2-CHꢁN-(1R,2R)ꢀC6H10ꢀNH2-k-
C,N,N)(PPh3)](ClO4) 4b as a result of the hydrolysis of the CꢁN bond not involved in the orthometallated ring. The molecular
structure of 4b·CH2Cl2 has been determined by X-ray diffraction methods. Cleavage of the PdꢀN bond trans to the Caryl atom can
be accomplished by coordination of strongly chelating ligands, such as acetylacetonate (acac) or bis(diphenylphosphino)ethane
(dppe), forming [Pd(acac-O,O%)(L-k-C,N)] 9 and [Pd(L-k-C,N)(dppe-P,P%)](ClO4) 12, while classical N,N%-chelating ligands such as
1,10-phenantroline (phen) or 2,2%-bipyridyl (bipy) behave as monodentate N-donor ligands yielding [Pd(L-k-C,N,N)(k1-N-
phen)](ClO4) 10 and [Pd(L-k-C,N,N)(k1-N-bipy)](ClO4) 11. Treatment of 1 with PtCl2(DMSO)2 (1:1 molar ratio) in refluxing
2-methoxyethanol gives Cl2Pt[(NH2)2C6H10ꢀN,N%] 13a and [Pt(Cl)(C6H2ꢀ4,5-(OMe)2ꢀ2-CHꢁN-(1R,2R)ꢀC6H10ꢀNH2-k-C,N,N)]
13b, while [Pt(Cl)(L-k-C,N,N)] 14 can be obtained by reaction of [Pt(m-Cl)(h3-2-MeꢀC3H4)]2 with 1 in refluxing CHCl3. Complexes
2 and 3 catalyzed the arylation of methyl acrylate giving good yields of the corresponding methyl cinnamates and TON up to
847 000. Complex 3 also catalyzes the hydroarylation of 2-norbornene, but with lower yields and without enantioselectivity.
© 2002 Elsevier Science B.V. All rights reserved.
Keywords: Palladium; Platinum; Orthometallated; Chiral; Heck reactions; Catalysis
derivatizations in the synthesis of chiral macrocycles of
C2-symmetry [2], in the synthesis of new chiral ligands
[3] and complexes [4] and in their applications in asym-
metric catalysis [5]. Recently, C,N,N-orthometallated
PtII-complexes based on cis- and trans-1,2-DACH have
been reported by Puddephatt [6]. This type of com-
plexes shows exciting properties, such as a high
stereoselectivity in the coordination of olefins [6a, 6b],
the structural modelization of electrophilic polynuclear
complexes [6c], the stereoselective formation of PtꢀC
bonds [6d, 6e, 6g], the carbon atom being a stereogenic
center, or the stereoselective oxidative addition to PtII
centers [6f].
1. Introduction
The chiral synthon (1R,2R)-1,2-diaminocyclohexane
(DACH), its enantiomer (1S,2S), and its derivatives,
have been widely used as powerful stereodirecting
reagents or ligands in asymmetric synthesis, and most
of their chemistry has been reviewed recently [1]. Al-
most as a general rule, the enantiomers are derivatized
and we can find very interesting examples of such
* Corresponding authors.
E-mail addresses: rafanava@posta.unizar.es (R. Navarro),
esteban@posta.unizar.es (E.P. Urriolabeitia).
0022-328X/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(02)01148-8

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J. Bra6o et al. / Journal of Organometallic Chemistry 650 (2002) 157–172
CꢀC bond forming reactions, such as the arylation of
methyl acrylate and the hydroarylation of 2-
norbornene.
2. Results and discussion
2.1. Synthesis of the orthometallated complexes
Fig. 1. Schematic representation and proton numbering for the
cyclometallated unit in complexes 2–8 and 14.
The bis-imine 1 (see Scheme 1) can be easily obtained
by condensation of 3,4-dimethoxybenzaldehyde with
(1R,2R)-l,2-DACH (1:1 molar ratio, CH2Cl2 room tem-
perature), in the presence of anhydrous MgSO4. The
formation of the iminic NꢁC bond can be inferred from
the IR spectrum of 1 due to the presence of a strong
absorption at 1647 cm−1. The NMR spectra of 1 show
that the molecule retains the C2-symmetry, since, only
one set of resonances is observed in each spectrum.
This fact also implies that the two CꢁN bonds display
the same configuration (E). The iminic proton appears
Given these precedents, and as part of our ongoing
work on the synthesis of orthometallated complexes of
PdII and PtII with additional functionalities [7,8], we
have now focussed our attention on chiral entities
derived from DACH. Our aim at the beginning of this
work was the synthesis of chiral, orthometallated, com-
plexes of PdII and PtII, in which three of the four
possible coordination sites were blocked by the cy-
clometallated ligand (see Fig. 1), leaving only one avail-
able position with a very specific stereochemistry.
Moreover, the chiral C,N,N-palladacycles could very
likely behave as catalysts in specific CꢀC couplings,
such as the Heck reaction, a field, which is in continu-
ous growth [9–12].
1
in the H-NMR as a singlet at 8.04 ppm, the aromatic
protons appear as a singlet (H2) and an AB spin system
(H5 and H6), and resonances attributed to the methoxy
groups and to the protons of the C6H10 skeleton are
also observed. The 13C{1H}-NMR spectrum of 1 shows
all the expected resonances.
In this paper, we report the synthesis of chiral palla-
dium and platinum orthometallated complexes derived
form the bis-imine (1R,2R)ꢀC6H10ꢀ[E-NꢁCHꢀC6H3ꢀ3,
4-(OMe)2]2 (1) and their behavior as catalysts in some
The treatment of
a methanolic suspension of
Pd(OAc)2 with 1 (1:1 molar ratio) at the reflux temper-
ature produces its gradual dissolution and the change
of its color from orange to bright yellow. The evapora-
Scheme 1.

J. Bra6o et al. / Journal of Organometallic Chemistry 650 (2002) 157–172
159
tion of the solution and Et2O addition gives complex
[Pd(OAc)(L-k-C,N,N)] (2) (see Scheme 1) as a yellow
solid. Further reaction of 2 with LiCl (excess, MeOH,
room temperature) affords [Pd(Cl)(L-k-C,N,N)] (3) as a
yellow solid.
The chloride ligand in 3 can be replaced by a variety
of neutral and anionic ligands. Treatment of 3 with
AgClO4 (acetone, 1:1 molar ratio) results in the precip-
itation of AgCl, which is removed by filtration. Further
reaction of the freshly prepared solvato derivative with
neutral L% ligands affords the cationic [Pd(L-k-
C,N,N)(L%)]ClO4 (L%=PPh3 4a, NCMe 5, pyridine 6 or
p-nitroaniline 7), while treatment of the solvato com-
plex with NaI affords the neutral [Pd(I)(L-k-C,N,N)] 8
(see Scheme 1).
All complexes 4a–8 show correct elemental analyses
and mass spectra for the proposed stoichiometries (see
Section 4). The IR spectra of 4a–8 show: (i) the disap-
pearance of the absorption due to the PdꢀCl stretch
(282 cm−1); (ii) absorptions corresponding to the pres-
ence of the L-k-C,N,N bonded ligand (1650–1500
cm−1); and (iii) absorptions assigned to the coordi-
nated L% ligands (see Section 4). For 6, the typical
bands of the pyridine could not be observed due to
overlapping in the 1600 cm−1 region, and for 8 the
PdꢀI stretch drops to 200 cm−1, the lowest limit of
detection of the spectrophotometer. The NMR spectra
of 4a–8 show the expected resonances for the C,N,N-
metallated ligand, in addition to signals, which are
characteristic of each ligand. Thus, three multiplets in
the low field region account for the presence of PPh3 in
4a, and a singlet at 2.01 ppm is attributed to the NCMe
ligand in 5. For 6 three resonances in the low field zone
The elemental analyses and the mass spectra of 2 and
3 are in keeping with the presence of one acetate (2) or
one chloride (3) ligand and one anionic L− ligand per
Pd atom. The mononuclear nature of 2 (and, by extrap-
olation, of 3) can be inferred from the value obtained in
the determination of the molecular weight of 2 in
CHCl3 solution (670 g mol−1), which is closer to that
calculated for a monomeric structure (574.96) than that
calculated for a binuclear system (1149.92). The IR
spectrum of 2 shows a very complicated pattern of six
intense absorptions in the 1650–1520 cm−1 region,
showing the presence of acetate, imine and aromatics,
but precluding their complete assignment.
The IR spectrum of 3 is very similar to that of 2, but
shows in addition a medium intensity band at 282
cm−1, due to the PdꢀCl stretch.
The 1H-NMR spectra of 2 and 3 unambiguously
reveal the presence of the orthopalladated L− ligand,
since the aromatic region shows seven well separated
signals, two attributed to the iminic protons (HA and
HB, see Fig. 1), three assigned to the aromatic protons
of the non-metallated ring (H2%, H6% and H5%) and two
attributed to the H3 and H6 protons of the metallated
ring. In addition, the NMR spectra shows the presence
of four sharp resonances in the 4.00–3.75 ppm region,
due to the methoxy groups, flanked by two broad
multiplets attributed to the protons attached to the
chiral carbon atoms (NC*H). In the high-field region,
the aliphatic protons of the cyclohexane unit appear as
complex multiplets (2.50–1.29 ppm for 2, 2.42–1.05
ppm for 3). For complex 2, the acetate ligand appears
as a singlet resonance at 1.63 ppm. The complete
attribution of these resonances has been carried out
are assigned to the pyridine ligand (8.49 ppm, Hortho
;
7.57 ppm, Hpara; 7.18 ppm, Hmeta) showing the free
rotation of the pyligand around the PdꢀN bond. More-
over, the resonance attributed to H6 (see Fig. 1) appears
at 5.85 ppm, strongly shifted to high-field due to the
anisotropic shielding produced by the pyligand [13],
reflecting their mutually cis disposition. For 7, the
N-coordination can be inferred from the observation of
an AB spin system for the NH2 protons. Finally, for 8,
the pattern of resonances is very similar to that de-
scribed for 3. The 13C{1H}-NMR spectra of 4a–8 show
the expected signals, and the 31P{1H}-NMR spectrum
of 4a shows a singlet at 35.87 ppm.
All complexes hitherto described (2–8) are stable at
room temperature to the oxygen and to the moisture
for long periods of time, both in solid state and in
solution, except 4a. This complex evolves slowly in
solution in wet solvents. When a solution of 4a is
allowed to stand for 24 h in wet CD2Cl2 or CDCl3, a
new complex 4b crystallized as yellow plates in nearly
quantitative yield. In the remaining solution it is possi-
ble to detect 3,4-dimethoxybenzaldehyde, showing that
the hydrolysis of one iminic CꢁN bond has occurred, as
portrayed in Equation 1. As a result of the hydrolysis
of the CꢁN bond the amine unit NH2, which remains
coordinated to the Pd center, is regenerated together
with the corresponding aldehyde, detected in solution.
Hydrolysis is suppressed when 4a is handled under Ar
1
with the help of the two-dimensional H-1H COSY and
NOESY experiments performed on complex 3. The key
feature for this attribution is the observation of the
protons H5% and H6% as an AB spin system (H6%, dd, 7.58
ppm; H5% d, 6.89 ppm). The COSY spectrum correlates
H6% with H2% (d, 8.32 ppm) and the NOESY spectrum
correlates H6% with the resonance at 8.26 ppm which,
according with Fig. 1, should be the iminic proton HA.
In addition, two singlet signals at 7.37 and 6.85 ppm
are attributed to the H6 and H3 protons of the metal-
lated ring, respectively, the latter showing a clear NOE
effect with the resonance at 7.88 ppm, which is at-
tributed to the iminic proton HB. The E-configuration
of the two iminic NꢁC bonds comes from the observa-
tion of a clear NOE effect between the resonances of
HA (8.26 ppm) and HB (7.88 ppm) with aliphatic pro-
tons of the cyclohexane ring (2.15 and 2.40 ppm,
respectively).

160
J. Bra6o et al. / Journal of Organometallic Chemistry 650 (2002) 157–172
in dry solvents. The elemental analysis and mass spec-
trum of 4b are in keeping with the structure depicted in
Equation 1 (see Section 4), and the IR spectrum of 4b
shows absorptions attributed to the presence of the
are presented in Table 2. The palladium atom is located
in a distorted square–planar environment, surrounded
by the orthometallated carbon atom, the P atom of the
PPh3 ligand and by the two nitrogen atoms, one with
an iminic CꢁN bond and one amine type atom. The
bond distances PdꢀC, PdꢀN(amine), PdꢀN(imine) and
PdꢀP and the intramolecular bond angles do not reveal
any notable features and are similar, within experimen-
tal errors, to those found in related orthometallated
complexes [7,8,14].
The easy generation of 4b from 4a, in contrast to the
high stability of the other compounds obtained, is
worthy of comment. For instance, the synthesis of 2 is
accomplished in refluxing methanol, and that of 3 is
also carried out in the same solvent (which always
contains water), without noticeable signs of hydrolysis.
The most important difference between 4a and the
1
NH2 group (3320, 3254 cm−1). The H-NMR spectrum
of 4b reveals, in the low field region, the signals at-
tributed to the PPh3 ligand and only three additional
resonances, corresponding to the iminic proton (8.05
ppm, HB) and to the H3 (6.98 ppm) and H6 (5.87 ppm)
protons of the orthometallated ring. In the central
region of the spectrum two singlet resonances can be
observed due to the methoxy groups (3.74 and 2.91
ppm), and four complex multiplets assigned to the
NC*H (3.67 and 2.78 ppm) and NH2 (3.36 and 2.48
ppm) protons. The 31P{1H}-NMR spectrum of 4b
shows a single peak at 36.86 ppm and the 13C{1H}-
NMR spectrum shows the expected signals.
(1)
The determination of the crystal structure of
4b·CH2Cl2 provides more structural information. The
complex crystallizes in the monoclinic, non-centrosym-
metric space group P21, showing that there is only one
diastereoisomer in the unit cell. There are two indepen-
dent molecules in the asymmetric unit, whose structural
parameters are almost identical, without significant de-
viations, as can be seen from Table 2. A drawing of one
of the organometallic cations is presented in Fig. 2.
Relevant crystallographic parameters of data collection
and crystal structure solution and refinement are indi-
cated in Table 1 and selected bond distances and angles
Table 1
Crystal data and structure refinement for 4b·CH2Cl2
Empirical formula
Formula weight
Temperature (K)
Wavelength (A)
Crystal system
C34H36Cl3N2O6PPd
812.37
173(2)
0.71073
Monoclinic
P21
14.4343(11)
17.5308(13)
14.6634(11)
107.238(2)°
3543.8(5)
,
Space group
,
a (A)
,
b (A)
,
c (A)
i (°)
3
,
V (A )
Z
4
Dcalc (mg m−3
)
1.523
0.841
1656
Absorption coefficient (mm−1
F(000)
)
Crystal size (mm)
q Range for data collection (°)
Reflections collected/unique
0.16×0.15×0.12
1.45–28.77
23 745/15 370
(Rint=0.0635)
0.9058, 0.8772
15 370/13/875
0.730
R1=0.0510,
wR2=0.0736
R1=0.1025,
wR2=0.0889
−0.01(4)
Max/min transmission
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I\2|(I)]
R indices (all data)
Absolute structure parameter
Fig. 2. Thermal ellipsoid plot of complex 4b. Only one of the two
independent molecules is shown. Non-hydrogen atoms are drawn at
the 50% probability level.
Largest difference peak and hole
0.759 and −0.594
−3
,
(e A
)

J. Bra6o et al. / Journal of Organometallic Chemistry 650 (2002) 157–172
161
Table 2
[Pd(acac-O,O%)(L-k-C,N)] 9 can be obtained as a yellow
solid. The O,O%-chelate coordination of the acac ligand
can be inferred from the position of the carbonyl
stretch in the IR spectrum (1588 and 1515 cm−1),
characteristic of this bonding mode [15], and from the
,
Selected bond lengths (A) and angles (°) for 4b-CH2Cl2
Bond lengths
Pd(1)ꢀC(101)
Pd(1)ꢀN(101)
Pd(1)ꢀN(102)
Pd(1)ꢀP(1)
1.988(12) Pd(2)ꢀC(201)
2.035(8) Pd(2)ꢀN(201)
2.122(9) Pd(2)ꢀN(202)
2.257(3) Pd(2)ꢀP(2)
2.003(10)
1.992(8)
2.144(8)
1
analysis of its NMR spectra: the H-NMR spectrum
2.236(3)
shows the C3ꢀH proton at 5.36 ppm, and the 13C{1H}-
NMR spectrum shows the C3 carbon atom at 99.96
ppm and the C(O) atoms at 187.71 and 186.06 ppm, all
of them being typical values for O-coordination [15].
The structure depicted in Scheme 1 for 9 resumes all
these facts. On the other hand, the reaction of 3 with
AgClO4 in acetone, followed by removal of the AgCl
and treatment of the resulting solution with dppe [bis(-
diphenylphosphino)ethane] (1:1:1 molar ratio, room
temperature) results in the synthesis of [Pd(L-
k,C,N)(dppe-P,P%)}ClO4 12, according to its elemental
analyses and mass spectrum (see Scheme 1). In this
case, the P,P%-bonding mode of the dppe ligand can be
inferred from the position of the resonances in the
31P{1H}-NMR spectrum (60.85 and 40.61 ppm), which
are very similar to those found in related P,P%-com-
plexes [8].
C(101)ꢀC(102)
C(101)ꢀC(106)
C(102)ꢀC(103)
C(103)ꢀO(101)
C(103)ꢀC(104)
O(101)ꢀC(114)
C(104)ꢀO(102)
C(104)ꢀC(105)
O(102)ꢀC(115)
C(105)ꢀC(106)
C(106)ꢀC(107)
C(107)ꢀN(101)
N(101)ꢀC(108)
C(108)ꢀC(113)
C(108)ꢀC(109)
C(109)ꢀC(110)
C(110)ꢀC(111)
C(111)ꢀC(112)
C(112)ꢀC(113)
C(113)ꢀN(102)
1.378(12) C(201)ꢀC(202)
1.394(15) C(201)ꢀC(206)
1.378(15) C(202)ꢀC(203)
1.356(10) O(201)ꢀC(204)
1.432(15) C(203)ꢀC(204)
1.410(12) O(201)ꢀC(214)
1.344(12) O(202)ꢀC(205)
1.412(14) C(204)ꢀC(205)
1.393(12) O(202)ꢀC(215)
1.371(16) C(205)ꢀC(206)
1.444(14) C(202)ꢀC(207)
1.249(12) C(207)ꢀN(201)
1.457(10) N(201)ꢀC(208)
1.531(10) C(208)ꢀC(213)
1.563(12) C(208)ꢀC(209)
1.520(13) C(209)ꢀC(210)
1.478(12) C(210)ꢀC(211)
1.514(12) C(211)ꢀC(212)
1.462(12) C(212)ꢀC(213)
1.511(10) C(213)ꢀN(202)
1.423(13)
1.353(13)
1.427(14)
1.388(13)
1.332(13)
1.402(12)
1.400(11)
1.378(15)
1.452(11)
1.385(16)
1.485(13)
1.294(12)
1.427(10)
1.491(10)
1.460(12)
1.533(13)
1.506(12)
1.533(13)
1.536(12)
1.511(11)
However, the behavior of other classic strong chelat-
ing ligands, such as 1,10-phenantroline (phen) and 2,2%-
bipyridyl (bipy) differs notably from that described for
9 and 12. The solution of the solvato complex [Pd(L-k-
C,N,N)(acetone)]ClCO4 reacts with the NꢀN ligands
(NꢀN=phen, bipy) (3: AgClO4: NꢀN=1:1:1 molar
ratio) giving complexes of stoichiometry [Pd(L)(NꢀN)]-
ClO4 (NꢀN=phen 10, bipy 11) according to their
elemental analyses and mass spectra. The 1H-NMR
spectra of these complexes are particularly informative.
At room temperature, they show seven sharp signals,
assigned to the orthometallated unit, and four broad
resonances. On cooling (CD2Cl2, 213 K) these four
broad signals split into eight sharp resonances, at-
tributed to the eight inequivalent protons of the NꢀN
ligands. These facts suggest that the L-k-C,N,N group
behaves statically in the NMR time scale, in the range
of temperatures measured, and that the terdentate coor-
dination is preserved. These facts also suggest that the
two rings of the NꢀN ligands behave equivalently (on
the NMR time scale) at room temperature and inequiv-
alently at low temperatures. Moreover, the equivalence
of the two halves of the NꢀN ligands at room tempera-
ture means that the molecular plane behaves as a
symmetry plane, in spite of the presence of chiral
centers. A reasonable explanation could be the assump-
tion that the NꢀN ligands are coordinated only through
one nitrogen atom and that there is a rapid exchange of
the N-bonded atoms at room temperature, which al-
most ceases at low temperatures. This fast exchange of
the N atoms can be easily rationalized through either a
dissociative mechanism of the PdꢀN bond or through a
fluxional process, which could be ‘a single oscillatory
Bond angles
C(101)ꢀPd(1)ꢀN(101) 81.1(4) N(201)ꢀPd(2)ꢀC(201) 82.7(3)
C(101)ꢀPd(1)ꢀN(102) 161.9(4) C(201)ꢀPd(2)ꢀN(202) 162.6(4)
N(101)ꢀPd(1)ꢀN(102) 81.0(3) N(201)ꢀPd(2)ꢀN(202) 80.3(3)
C(101)ꢀPd(1)ꢀP(1)
N(101)ꢀPd(1)ꢀP(1)
N(102)ꢀPd(1)ꢀP(1)
97.4(3) C(201)ꢀPd(2)ꢀP(2)
174.9(2) N(201)ꢀPd(2)ꢀP(2)
100.7(2) N(202)ꢀPd(2)ꢀP(2)
96.1(3)
178.7(2)
100.8(2)
other complexes lies probably in the steric requirements
of the L% ligand, and this could be a reasonable argu-
ment to explain the moderate stability of 4a. Thus, the
cis arrangement of the bulky PPh3 ligand and the iminic
fragment ꢀNꢁC(H)C6H3-3%,4%-(OMe)2 which, moreover,
presents E configuration and is directed towards the
PPh3 group, could contribute to the destabilization of
the resulting molecule 4a by steric hindrance. This is
not observed in the other complexes, probably because,
the ligands coordinated in this position are smaller than
PPh3 (Cl 3, I 8), or linear (NCMe 5), or they can
accommodate through free rotation in a given position
to minimize steric repulsions (OAc 2, pyridine 6, p-ni-
troaniline 7). We have not performed any other reac-
tions with bulky ligands and different donor atoms in
order to establish whether or not this reaction is a
general process.
In complexes 2–8 the ligand L acts as a C,N,N-ter-
dentate group. The PdꢀN bond trans to the orthometal-
lated carbon atom can be easily cleaved by reaction of
3 (or its solvato derivative) with strong chelating lig-
ands. Treatment of 3 with Tl(acac) (1:1 molar ratio,
CH2Cl2, acac=acetylacetonate) produces the immedi-
ate precipitation of TlCl, which is removed by filtra-
tion. From the resulting solution, the complex

162
J. Bra6o et al. / Journal of Organometallic Chemistry 650 (2002) 157–172
Scheme 2.
tion to the Pt center instead to the Pd center. Thus, the
1H-NMR spectrum of 14 reveals the resonances at-
tributed to the iminic protons HA, HB and H6 with 195Pt
satellites, showing values of the coupling constants,
which are similar to others reported in the literature [6].
motion of the potentially didentate ligand via a trigo-
nal–bipyramidal transition state’. Similar proposals
have been reported for related systems [8].
We have also attempted to prepare orthometallated
PtII complexes, starting from PtII substrates and 1
through CꢀH activation. PtII complexes have been used
frequently to promote CꢀH bond activation [16]. For
instance, PtCl2(DMSO)2 (DMSO=Me2SꢁO) has been
employed in a wide variety of CꢀH bond activation
reactions [17]. The treatment of a white suspension of
PtCl2(DMSO)2 with 1 (1:1 molar ratio) in refluxing
2-methoxyethanol for 22 h results in the formation of a
mixture of two products (13a and 13b, see Scheme 2),
which are easily separable due to their different solubil-
ity. Complex 13a, insoluble in the alcoholic medium, is
the coordination compound Cl2Pt[(NH2)2C6H10ꢀN,N%],
while complex 13b, soluble in 2-methoxyethanol and
isolated after evaporation and precipitation with Et2O,
is the orthometallated derivative [Pt(Cl)(C6H2-4,5-
(OMe)2-2-CHꢁN-(1R,2R)-C6H10ꢀNH2-k-C,N,N)]. The
analytical and spectroscopic parameters of 13a and 13b
unambiguously establish their stoichiometry and stereo-
chemistry (see Scheme 2, Section 4). Probably, the
strong reaction conditions and the protic nature of the
solvent are responsible for the behavior observed.
The synthesis of [Pt(Cl)(L-k-C,N,N] 14 is easily ac-
complished by reacting 1 and the dimer [18] [Pt(m-
Cl)(h3-2-MeꢀC3H4)]2 (2:1 molar ratio) in refluxing
CHCl3 for 5 h (see Scheme 2). This is a very convenient
method for the synthesis of cycloplatinated derivatives
[19]. The spectral data of 14 are very similar to those of
3, with the logical differences arising from the coordina-
3
The different values of the JPtꢀH for the iminic protons
3
(NꢁCHA, 8.77 ppm, JPtꢀH=44 Hz; NꢁCHB, 8.21 ppm,
3JPtꢀH=147 Hz) could be due to the different trans
influences of their respective trans ligands, even if both
iminic CꢁN bonds show the same geometry. Thus, the
iminic proton HA is located trans to the orthometal-
lated carbon atom, while the iminic proton HB is lo-
cated trans to the chlorine atom; the higher trans
influence of the carbon atom with respect to the Cl
atom results in a higher labilization of the PtꢀN(ꢁCHA)
bond, and then in a lower value of the coupling
constant.
2.2. Catalytic reactions
After the discovery of the exceptional activity in the
Heck reaction [20] of the orthometallated complex
[Pd(m-OAc)(CH2C6H4-2-P(o-tolyl)2)]2 (o-tolyl=ortho-
MeC6H4) [21], the investigation of the catalytic proper-
ties of different C,X-cyclopalladated complexes in
Heck-type reactions is, at present, one of the most
active fields of research in Pd-catalyzed processes [9–
12]. We have studied the catalytic activity of complexes
2 and 3 in Heck or Heck-type reactions.
Complexes 2 and 3 effectively catalyze the arylation
of methyl acrylate (see Equation 2; Section 4; Table 3)
in refluxing N,N-dimethylacetamide [21a] for 24 h,

J. Bra6o et al. / Journal of Organometallic Chemistry 650 (2002) 157–172
163
catalyst can be as low as 10−6 (mmol catalyst per mmol
aryl halide) (entries 4, 8, 11 and 15) giving the corre-
sponding methyl cinnamates in moderate to good
yields. The comparison of the different haloarenes (re-
action A: 4-BrC6H4CN; reaction B: IC6H5; reaction C:
4-BrC6H4CHO; reaction D: BrC6H5; see Equation 2)
shows that in general, the yields of the isolated prod-
ucts using iodobenzene or 4-bromobenzonitrile are
more or less similar (for instance, entries 2 and 9, 3 and
10, 4 and 11), that slightly lower yields are obtained
with 4-bromobenzaldehyde (entries 2, 9, 16 or 5, 12, 18)
and that the lowest yields are obtained with bromoben-
zene (entries 21, 22). No reaction was observed using
chlorobenzene (catalyst 3, 1%). With respect to the
compared activity of 2 and 3: complex 3, in general,
gives better yields (entries 1 and 5, 2 and 6, 3 and 7, for
instance) although, the differences are not spectacular
and can be the opposite in some cases (entries 4 and 8,
9 and 13).
giving the corresponding methyl E-cinnamates, as white
solids or yellow oils, in moderate to good yields. We
have observed some general features: (i) all reactions
start after an induction period of, ca. 30 min, in which
the initial yellow solution becomes an orange or red
suspension, but with no evidence of black palladium in
this suspension; (ii) it has not been possible to recover
the catalyst at the end of the reaction; (iii) however,
these solutions can reassume the catalytic reaction after
the addition of a second batch of reagents, although,
with a lower activity than that shown in the first run.
For instance, 3 (1%) catalyzes the phenylation of
methyl acrylate to give the methyl cinnamate in 82.6%
yield (entry 12). If, instead of the workup, a second
batch of reagents is added at the end of this first run
and heating is maintained a further 24 h, the methyl
cinnamate is obtained with a global yield of 61.4%,
which means that the yield of the second run is 40.2%,
assuming the same yield for the first run.
Prompted by the results obtained in the arylation of
methyl acrylate and taking advantage of the chiral
character of our catalysts, we decided to explore the
catalytic behavior of 3 in asymmetric Heck reactions
[22], namely in the hydroarylation of 2-norbornene.
This reaction, catalyzed enantioselectively by Pd com-
plexes, has been known since 1991 [23] but it is being
exhaustively studied at the present time [24] given that
this methodology could be successfully employed in the
synthesis of natural products analogous to the epiba-
tidine alkaloid [25]. The reaction scheme is presented in
(2)
As can be seen in Table 3, both complexes 2 and 3
are effective catalysts in the Heck reaction of methyl
acrylate with iodobenzene, bromobenzene or activated
aryl bromides. In some cases, the concentration of the
Table 3
Catalytic Heck arylation of methyl acrylate
Run
Reaction
Catalyst
Catalyst (%mmol) a
Yield (%) b
TON
1
2
3
4
5
6
7
8
A
A
A
A
A
A
A
A
B
B
B
B
B
B
B
C
C
C
C
C
D
D
2
2
2
2
3
3
3
3
2
2
2
3
3
3
3
2
2
3
3
3
3
3
1
0.1
0.01
0.0001
1
78.4
84.6
62.0
74.0
86.7
89.9
100
64.1
79.0
66.8
84.7
82.6
74.7
95.7
42.6
74.7
38.5
74.5
71.5
66.0
68.1
0.0
78.4
846
6200
740 000
86.7
0.1
899
0.01
0.0001
0.1
0.01
0.0001
1
10 000
641 000
790
6680
847 000
82.6
9
10
11
12
13
14
15
16
17
18
19
20
21
22
0.1
747
0.01
0.0001
0.1
0.01
1
0.1
0.01
1
9570
426 000
747
3850
74.5
715
6600
68.1
0.1
0.0
a Calculated with respect to aryl halide.
b Isolated product.

164
J. Bra6o et al. / Journal of Organometallic Chemistry 650 (2002) 157–172
Table 4
Catalytic Heck hydroarylation of 2-norbornene
Run
Reaction
Catalyst
Catalyst (% mmol) a
Yield (%) b
TON
Optical yield d
1
2
3
4
5
6
7
8
A
A
A
B
B
B
B
C
3
3
3
3
3
3
3
3
3
3
3
3
3
1
53
57.2
–
81
89.2
100
–
84
66.4
–
53
572
–
81
892
10 000
–
84
664
–
0.1
0.01
1
0.1
0.01
0.0001
1
0.1
0.01
1
–
–
9
C
C
10
11
12
13
–
–
–
–
ClPh c
–
–
–
–
–
–
BrC6H4Me c
BrC6H4OMe c
1
1
a Calculated with respect to uryl halide.
b Isolated product.
c Same reaction conditions.
d See text.
actually pre-catalysts, and that the true catalytic species
are nanoparticles [26] of Pd0 generated by decomposi-
tion of the catalyst. The presence of Pd0 nanoparticles
has been proved in some cases [26] and is suspected in
other cases [12a, 12b]. This hypothesis could explain
our observations on: (i) the presence of an activation
period; (ii) the non-recovery the catalyst at the end of
the reaction; (iii) the absence of Pd0 black, as the
nanoparticles generated are stabilized in the presence of
ammonium salts, formed during the reaction [26] and
(iv) the lack of enantioselectivity, as the chiral environ-
ment of the Pd center is destroyed during the activation
period.
Equation 3 (also see Section 4) and the results obtained
are presented in Table 4. As can be seen from Table 4,
3 catalyzes the arylation of 2-norbornene giving the
corresponding aryl norbornanes in moderate to excel-
lent yields. However, the amount of catalyst required is
higher than in the arylation of methyl acrylate, and
concentrations of catalyst lower than 10−4 (mmol 3 per
mmol aryl halide) did not give detectable conversions
(entry 7). The best results were obtained with phenyl
iodide, and activated aryl bromides gave lower conver-
sions (entries 1, 4, 8 and 2, 5, 9). The amount of
catalyst in the case of aryl bromides must be at least
10−3 (mmol 3 per mmol aryl halide) to achieve good
conversions, since lower concentrations did not give
detectable conversions (entries 3 and 10). Electron-rich
aryl bromides (4-bromotoluene or 4-bromoanisol) were
unreactive (entries 12 and 13), as well as chlorobenzene
(entry 11), even with 1% of catalyst 3.
Other studies are currently in progress in order to
obtain new ligands, based on the chiral entity (1R,2R)-
diaminocyclohexane, which could act as efficient cata-
lysts in enantio- and diastereoselective asymmetric
Heck reactions.
3. Conclusions
We have reported several new palladium and plat-
inum neutral and cationic complexes, based on the
orthometallated chiral diimine ligand [(C6H2-4,5-
(OMe)2 - 2 - CHꢁN - (1R,2R) - C6H10ꢀNꢁCHꢀC6H3 - 3%,4%-
(OMe)2-k-C,N,N)]. This ligand acts mainly as a C,N,N-
terdentate ligand [M(L-k-C,N.N)], even in presence of
classic chelating ligands such as phen or bipy, showing
the stability of the C,N,N-coordination. The PdꢀN
bond trans to the arylic carbon atom can be cleaved by
strong chelating ligands such as acac or dppe. The
iminic CꢁN bonds can be hydrolyzed once, generating
the new C,N,N-ligand [(C6H2-4,5-(OMe)2-2-CHꢁN-
(1R,2R)-C6H10ꢀNH2-k-C,N,N)] (4b and 13b) or twice,
(3)
However, the optical purity of the arylnorbornanes
obtained, based on the [a]D values, is close to zero in all
cases, showing the absence of enantiomeric discrimina-
tion. Thus, although these complexes are more or less
effective catalysts in Heck-type processes, they are not
suitable for producing asymmetric induction in the
reported conditions, which are similar to others de-
scribed in the literature [24]. A reasonable explanation
for this lack of enantioselectivity can be given on the
basis of recent work in this area [9, 12a, 12b], which
suggests that the C,N-orthopalladated complexes are

J. Bra6o et al. / Journal of Organometallic Chemistry 650 (2002) 157–172
165
1
regenerating the starting DACH, which remains N,N-
coordinated (13a). Complexes [Pd(OAc)(L-k-CN,N)]
(2) and [Pd(Cl)(L-k-C,N,N)] (3) are adequate pre-cata-
lysts for Heck or Heck-type reactions. However, they
are not suitable precursors in asymmetric Heck reac-
tions in the conditions studied.
1511 (CꢁC). H-NMR (CDCl3): l (ppm), 8.04 (s, 1H,
NꢁCH), 7.21 (s, 1H, H2, C6H3), 6.96 (d, 1H, H5, C6H3),
3
6.71 (d, 1H, H6, C6H3, JHꢀH=7.80 Hz), 3.81 (s, 3H,
OCH3), 3.79 (s, 3H, OCH3), 3.31 (br s, 1H, NC*H,
C6H10), 1.81 (br s, 3H, C6H10), 1.43 (br s, 1H, C6H10).
13C{1H}-NMR (CDCl3): l (ppm) 160.64 (NꢁCH),
150.96, 149.03, 129.60, 122.64, 110.31, 108.92 (C6H3),
73.58 (NꢀC*H), 55.90, 55.85 (OCH3), 32.99, 24.55
(CH2, C6H10).
4. Experimental
Caution! Perchlorate salts of metal complexes with
organic ligands are potentially explosive. Only small
amounts of these materials should be prepared and they
should be handled with great caution. See J. Chem. Ed.
50 (1973) A335.
4.3. Preparation of [Pd(OAc)(C6H2-4,5-(OMe)2-
2-CHꢁN-(1R,2R)-C6H10ꢀNꢁCHꢀC6H3-3%,4%-(OMe)2-
s-C,N,N)] (2)
To a suspension of [Pd(OOCCH3)2] (0.500 g, 2.22
mmol) in MeOH (20 ml), 1 (0.9146 g, 2.23 mmol) was
added. The resulting mixture was refluxed for 1 h.
During the reaction time, some decomposition was
evident. Once cooled, the resulting black suspension
was treated with activated charcoal and filtered over
Celite, giving a bright yellow solution. This solution
was evaporated to small volume (2 ml) and Et2O (20
ml) was added, giving 2 as a yellow solid, which was
filtered, washed with Et2O (20 ml) and air dried. Ob-
4.1. General methods
Solvents were dried and distilled under argon before
use. Elemental analyses were carried out in a Perkin–
Elmer 240-B microanalyser. Infrared spectra (4000–200
cm−1) were recorded on a Perkin–Elmer 883 infrared
spectrophotometer from nujol mulls between
1
polyethylene sheets. H (300.13 MHz), 13C{H} (75.47
MHz) and 31P{1H} (121.49 MHz)-NMR spectra were
recorded in CDCl3 or CD2Cl2 solutions at room tem-
perature (r.t.) (unless otherwise stated) on a Bruker
ARX-300 spectrometer; 1H and 13C{1H} were refer-
enced using the solvent signal as the internal standard
and 31P{1H} was externally referenced to H3PO4 (85%).
tained: 1.189
g
(93% yield). Anal. Calc. for
C26H32N2O6Pd: C, 54.31; H, 5.61; N, 4.87. Found: C,
54.41; H, 5.69; N, 4.70%. Mol. wt. (CHCl3): Found:
670 (Calc. 574.95). Mass Spect. (FAB+) [m/z, (%)]:
515 (100%) [(MꢀOAc)+]. IR (w, cm−1): 1644, 1619,
1601, 1587, 1545, 1520 (NꢁCH+OAc+CꢁC). 1H-
1
4
The two dimensional H-1H COSY and1H–1H NOESY
NMR (CDCl3): l (ppm), 8.36 (d, 1H, NꢁCHA, JHꢀH
=
4
experiments for complexes 3 and 8 were performed at a
measuring frequency of 300.13 MHz. The data were
acquired using a phase-sensitive method into a 512×
1024 matrix, and then transformed into 1024×1024
points using a sine window in each dimension. The
mixing time was 400 ms for the NOESY experiments.
Mass spectra (positive ion F.A.B.) were recorded on a
V.G. Autospec spectrometer from CH2Cl2 solutions.
1.8 Hz), 7.85 (d, 1H, H2%, JH2%ꢀH6%=1.8 Hz), 7.82 (d,
1H, NꢁCHB, 4JHꢀH=2.1 Hz), 7.57 (dd, 1H, H6%,
3JH6%ꢀH5%=8.4 Hz), 6.92 (d, 1H, H5%), 6.84, 6,75 (2s, 2H,
H3+H6), 4.11 (m, 1H, NꢀC*H), 4.05 (s, 3H, OCH3),
3.91 (s, 3H, OCH3), 3.88 (s, 3H, OCH3), 3.78 (s, 3H,
OCH3), 3.31 (m, 1H, NꢀC*H), 2.48 (m, 1H, C6H10),
2.41 (m, 1H, C6H10), 1.94 (m, 2H, C6H10), 1.63 (s, 3H,
CO2CH3), 1.49–1.29 (m, 4H, C6H10). 13C{1H}-NMR
(CDCl3): l (ppm), 177.32 (CO2), 167.66 (NꢁCH),
162.91 (NꢁCH), 152.46, 151.43, 150.33, 148.46, 146.39,
139.87, 125.91, 125.16, 115.76, 111.96, 110.57, 110.28
(C6H2+C6H3), 70.98 (NC*H), 67.94 (NC*H), 56.25.
56.11, 56.04, 55.90 (4 OMe), 29.66, 29.49, 24.21, 23.99
(CH2 of C6H10), 23.61 (CO2CH3).
4.2. Preparation of
(1R,2R)-C6H10-[E-NꢁCHꢀC6H3-3,4-(OMe)2]2 (1)
To a solution of 3,4-(OMe)2ꢀC6H3ꢀCHO (2.920 g,
17.5 mmol) in CH2Cl2 (15 ml) at r.t., (1R,2R)-1,2-di-
aminocyclohexane (1.003 g, 8.79 mmol) and anhydrous
MgSO4 were added. The reaction mixture was stirred
for 30 min and then filtered. The resulting solution was
evaporated to dryness and the oily residue was treated
with n-hexane (40 ml) and continuous stirring, giving 1
as a white solid. This solid was filtered, washed with
additional n-hexane (20 ml) and air dried. Obtained:
3.086 g (85.5% yield). Anal. Calc. for C24H30N2O4: C,
70.22; H, 7.36; N, 6.82. Found: C, 69.79; H, 7.37; N,
7.32%. Mass Spect. (FAB+) [m/z, (%)]: 411 (100%)
[(M+H)+]. IR (w, cm−1): 1647(NꢁCH), 1602, 1586,
4.4. Preparation of [Pd(Cl)(C6H2-4,5-(OMe)2-
2-CHꢁN-(1R,2R)-C6H10ꢀNꢁCHꢀC6H3-3%,4%-(OMe)2-
s-C,N,N)] (3)
To an orange solution of 2 (0.500 g, 0.87 mmol) in
MeOH (20 ml), an excess of LiCl (0.147 g, 3.46 mmol)
was added. A yellow solid precipitated almost instanta-
neously. After 5 min stirring, this solid was filtered,
washed with MeOH (10 ml) and Et2O (10 ml) and air
dried. Obtained: 0.380 g (79.3% yield). Anal. Calc. for

166
J. Bra6o et al. / Journal of Organometallic Chemistry 650 (2002) 157–172
C24H29ClN2O4Pd: C, 52.28; H, 5.30; N, 5.08. Found: C,
52.06; H, 5.38; N, 4.79%. IR (w, cm−1): 1644, 1618,
1602, 1588, 1545, 1520 (NꢁCH+CꢁC), 282 (PdꢀCl).
Mass Spect. (FAB+) [m/z, (%)]: 515 (100%) [(MꢀC1)+
]. 1H-NMR (CDCl3): l (ppm), 8.32 (d, 1H, H2%,
4JH2%ꢀH6%=2.1 Hz), 8.26 (s, broad, 1H, NꢁCHA), 7.88
(d, 1H, NꢁCHB, 4JHꢀH=2.1 Hz), 7.58 (dd, 1H, H6%,
3JH6%ꢀH5%=8.4 Hz), 7.37 (s, 1H, H6), 6.89 (d, 1H, H5%),
6.85 (s, 1H, H3), 4.06 (s, 3H, OCH3), 3.93 (s, 3H,
OCH3), 3.90 (s. 3H, OCH3), 3.84 (m, 1H, NꢀC*H), 3.75
(s, 3H, OCH3), 3.14 (m, 1H, NꢀC*H), 2.40 (m, 1H,
C6H10), 2.15 (m, 1H, C6H10), 1.84 (m, 2H, C6H10),
1.55–1.05 (m, 4H, C6H10), 13C{1H}-NMR (CDCl3): l
(ppm), 168.53 (NꢁCH), 163.25 (NꢁCH), 152.96, 151.39,
149.58, 148.59, 146.14, 140.63, 126.72, 125.43, 117.87,
113.09, 110.95, 110.06 (C6H2+C6H3), 71.58 (NC*H),
68.05 (NC*H), 56.84, 56.21, 56.11, 55.98 (4 OMe),
30.12, 29.42, 24.22, 23.93 (CH2 of C6H10).
was not observed), 73.71, 70.07 (NꢀC*H), 56.19
(2OMe), 56.07 (OMe), 56.00 (OMe), 30.24, 28.93,
24.23, 23.94 (CH2 of C6H10).
4.6. Preparation of [Pd(C6H2-4,5-(OMe)2-2-CHꢁN-
(1R,2R)-C6H10ꢀNH2-s-C,N,N)(PPh3)](ClO4) (4b)
Complex 4a was dissolved in wet CDCl3 (1 ml) and
this solution was left to stand for 24 h. After this time,
complex 4b crystallized as small yellow plates. The yield
was quantitative. Anal. Calc. for C33H36ClN2O6PPd: C,
54.33; H, 4.97; N, 3.84. Found: C, 54.52; H, 5.30; N,
3.79%. IR (w, cm−1): 3320, 3254 (NH2). 1686, 1621,
1588, 1520 (NꢁCH+CꢁC), 1094, 623 (ClO4). Mass
Spect. (FAB+) [m/z, (%)]: 630 (100%) [(MꢀClO4)+].
1H-NMR (CD2Cl2): l (ppm), 8.05 (dd, 1H, NꢁCH,
4
4JPꢀH=9.9 Hz, JHꢀH=2.1 Hz), 7.69–7.62 (m, 6H, Ho,
PPh3), 7.59–7.44 (m, 9H, Hm+Hp, PPh3), 6.98 (s, 1H,
H3), 5.87 (d, 1H, H6, 4JPꢀH=3.3 Hz), 3.74 (s, 3H,
OCH3), 3.67 (m, 1H, NꢀC*H), 3.36 (t, 1H, NH2,
2JHꢀH=3JPꢀH=12 Hz), 2.91 (s, 3H, OCH3), 2.78 (m,
1H, NꢀC*H), 2.48 (m, 1H, NH2), 1.94 (m, 1H, C6H10),
1.79 (m, 3H, C6H10), 1.51 (m, 1H, C6H10), 1.35 (m, 2H,
C6H10), 1.27–1.12 (m, 1H, C6H10). 31P{1H}-NMR
(CD2Cl2): l (ppm) 36.86. 13C{1H}-NMR (CD2Cl2): l
(ppm), 169.81 (NꢁCH), 154.74, 150.43, 146.82, 143.55,
121.82 (d, JPꢀC=9.8 Hz), 112.95 (C6H2), 134.91 (d,
4.5. Preparation of [Pd(C6H2-4,5-(OMe)2-2-CHꢁN-
(1R,2R)-C6H10ꢀNꢁCHꢀC6H3-3%,4%-(OMe)2-s-C,N,N)-
(PPh3)](ClO4) (4a)
Complex 3 (0.100 g, 0.181 mmol) was dissolved in
acetone (10 ml) and treated with AgClO4 (0.037 g,
0.181 mmol) in the absence of light. After 30 min
stirring at r.t., the suspension was filtered and to the
freshly obtained solution PPh3 (0.0472, 0.181 mmol)
was added. The resulting solution was stirred at r.t. for
30 min, the solvent evaporated to dryness and the oily
residue treated with Et2O (40 ml), giving 4a as a yellow
solid. Obtained: 0.148 g (93.1% yield). Crystals of 4a
0.25CH2Cl2 were grown by vapor diffusion of Et2O into
a CH2Cl2 solution of 4a. The presence of solvent of
JPꢀC=12.8 Hz), 132.10, 129.76 (d, JPꢀC=41 Hz),
129.62 (d, PꢀC=10.6 Hz) (PPh3), 67.37, 62.99
J
(NꢀC*H), 56.35, 55.43 (OMe), 35.29, 29.29, 24.97,
23.94 (CH2 of C6H10).
4.7. Preparation of [Pd(C6H2-4,5-(OMe)2-2-CHꢁN-
(1R,2R)-C6H10ꢀNꢁCHꢀC6H3-3%,4%-(OMe)2-s-C,N,N)-
(NCMe)](ClO4) (5)
1
crystallization was checked by H-NMR. These crystals
were used for analytical and spectroscopic purposes.
Anal. Calc. for C42H44ClN2O8PPd·0.25 CH2Cl2: C,
56.45; H, 4.99; N, 3.11. Found: C, 56.01; H, 5.17; N,
3.04%. IR (w, cm−1): 1635, (605, 1595, 1555, 1525
(NꢁCH+CꢁC), 1094, 623 (ClO4). Mass Spect. (FAB+
) [m/z, (%)]: 777 (100%) [(MꢀClO4)+], 515 (90%)
Complex 3 (0.100 g, 0.181 mmol) was suspended in
acetonitrile (10 ml) and treated with AgClO4 (0.037 g,
0.181 mmol) in the absence of light. After 30 min
stirring at r.t. the suspension was filtered, the resulting
solution was evaporated to dryness and the oily residue
was treated with Et2O (40 ml), giving 5 as a yellow
solid. Obtained: 0.084 g (70.7% yield). Anal. Calc. for
C26H32ClN3O8Pd: C, 47.57; H, 4.91; N, 6.40. Found: C,
47.62; H, 4.84; N, 6.52%. IR (w, cm−1): 2324, 2320
(CN), 1640, 1602, 1548, 1520 (NꢁC+CꢁC), 1086, 623
(ClO4). Mass Spect. (FAB+) [m/z, (%)]: 515 (100%)
[(MꢀClO4ꢀNCMe)+]. 1H-NMR (CD2Cl2): l (ppm),
1
[(MꢀClO4ꢀPPh3)+]. H-NMR (CDCl3): l (ppm), 8.42
3
4
(dd, 1H, H6%, JH6%ꢀH5%=9.9 Hz, JH2%ꢀH6%=2.1 Hz), 8.28
4
4
(dd, 1H, NꢁCHB, JPꢀH=8.1 Hz, JHꢀH=1.8 Hz), 8.27
(s, broad, 1H, NꢁCHA), 7.45–7.24 (m, 16H, H3+
PPh3), 6.55 (d, 1H, H2%), 6.50 (d, 1H, H5%), 5,86 (d, 1H,
4
H6, JPꢀH=4.2 Hz), 4.12 (m, 1H, NꢀC*H), 3.81 (s, 3H,
OCH3), 3.76 (s, 3H, OCH3), 3.69 (s, 3H, OCH3), 3.41
(m, 1H, NꢀC*H), 2.80 (s. 3H, OCH3), 2.69 (m, 1H,
C6H10), 2.27 (m, 1H, C6H10), 1.93 (m, 2H, C6H10), 1.61
(m, 2H, C6H10), 1.31 (m, 2H, C6H10). 31P{1H}-NMR
(CDCl3): l (ppm) 35.87. 13C{1H}-NMR (CDCl3): l
(ppm), 172.36, 165.30 (NꢁCH), 152.60, 148.62, 146.17,
143.17, 126.88, 121.20, 120.12, 114.23, 113.35, 110.71,
110.50, 109.01 (C6H3+C6H2), 134.44 (d, JPꢀC=12.1
Hz), 131.37, 128.71 (d, JPꢀC=10.6 Hz) (PPh3, the Cipso
4
8.66 (d, 1H, NꢁCHA, JHꢀH=1.8 Hz), 7.99 (d. 1H, H2%,
3
4JH2%ꢀH6%=2.1 Hz), 7.71 (dd, 1H, H6%, JH6%ꢀH5%=8.4
4
Hz), 7.57 (d, 1H, NꢁCHB, JHꢀH=1.8 Hz). 7.09 (d, 1H,
H5%), 7.06 (s, 1H, H6), 6.58 (s, 1H, H3), 3.97 (s, 3H,
OCH3), 3.95 (s, 3H, OCH3), 3.90 (s, 4H, OCH3+
NꢀC*H), 3.79 (s, 3H, OCH3), 3.40 (m, 1H, NꢀC*H),
2.55 (m, 2H, C6H10), 2.01 (m, broad, 5H, NCMe+
C6H10), 1.56–1.34 (m, 4H, C6H10). 13C{1H}-NMR

J. Bra6o et al. / Journal of Organometallic Chemistry 650 (2002) 157–172
167
1
(CD2Cl2): l (ppm), 172.52 (NꢁCH), 165.65 (NꢁCH),
153.39, 151.27, 151.17, 149.13, 147.78, 140.87, 127.10,
124.31, 122.31, 116.87, 112.99, 112.89, 111.20 (C6H2+
C6H3+CN), 72.43 (NC*H), 69.19 (NC*H), 56.67,
56.62, 56.56, 56.52 (4OMe), 29.85, 29.72, 24.38, 24.20
(CH2 of C6H10), 3.22 (NCMe).
N2O2)+]. H-NMR (CDCl3): l (ppm), 8.35 (s, broad,
3
1H, NꢁCHA), 8.25 (d, 1H, H6%, JH6%ꢀH5%=8.4 Hz). 8.03
(m, 2H, C6H4), 7.83 (d, 1H, NꢁCHB, JHꢀH=2.1 Hz),
4
7.79 (s, broad, 1H, H2%, 7.30 (d, 1H, H5%), 6.92 (m, 2H,
C6H4), 6.87: 6.68 (2s, 2H, H3+H6), 5.77 (d, 1H, NH2,
2JHꢀH=10.8 Hz), 5.23 (d, 1H, NH2), 3.97 (s, 4H,
OCH3+NꢀC*H), 3.93 (s, 3H, OCH3), 3.81 (s, 3H,
OCH3), 3.73 (s, 3H, OCH3), 3.22 (m, 1H, NꢀC*H), 2.48
(m, 1H, C6H10), 2.35 (m, 1H, C6H10), 1.88 (m, 2H,
C6H10), 1.49–1.27 (m, 4H, C6H10). 13C{1H)-NMR
(CDCl3): l (ppm), 170.85 (NꢁCH), 164.26 (NꢁCH),
153.25, 150.67, 149.38, 147.38, 147.16, 144.83, 140.91,
126.27, 125.75, 124.38, 122.71, 120.36, 115.35, 113.43,
112.79, 112.36 (C6H2+C6H3+C6H4), 72.12 (NC*H),
68.87 (NC*H), 56.66, 56.39, 56.16, 56.09 (4OMe),
29.56, 29.19, 23.96, 23.68 (CH2 of C6H10).
4.8. Preparation of [Pd(C6H2-4,5-(OMe)2-2-CHꢁN-
(1R,2R)-C6H10ꢀNꢁCHꢀC6H3-3%,4%-(OMe)2-s-C,N,N)-
(NC5H5)](ClO4) (6)
Complex 6 was obtained as described for 4. Complex
3 (0.100 g, 0.181 mmol) was reacted in acetone with
AgClO4 (0.037 g, 0.181 mmol) and pyridine (14.6 ml,
0.181 mmol) to give 6 as a yellow solid. Obtained: 0.114
g (90.5% yield). Anal. Calc. for C29H34ClN3O8Pd: C,
50. 16; H, 4.93; N, 6.05. Found: C, 49.83; H, 5.06; N,
6.09%. IR (w, cm−1): 1635, 1610, 1585, 1555, 1545,
1520 (NꢁCH+CꢁC+py), 1100, 624 (ClO4). Mass
Spect. (FAB+) [m/z, (%)]: 594 (27%) [(MꢀClO4)+], 515
(100%) [(MꢀClO4ꢀNC5H5)+]. 1H-NMR (CDCl3): l
4.10. Preparation of [Pd(I)(C6H2-4,5-(OMe)2-2-
CHꢁN-(1R,2R)-C6H10ꢀNꢁCHꢀC6H3-3%,4%-(OMe)2-
s-C,N,N)] (8)
4
(ppm), 8.68 (d, 1H, NꢁCHA, JHꢀH=1.8 Hz), 8.49 (dd,
To a solution of 3 (0.193 g, 0.351 mmol) in acetone
(15 ml) AgClO4 (0.073 g, 0.351 mmol) was added in the
absence of light. After 30 min stirring, the suspension
was filtered and NaI (0.052 g, 0.346 mmol) was added
to the freshly obtained solution. The resulting suspen-
sion was stirred (r.t.) for 1 h, filtered and the yellow
solid (8) washed with acetone (10 ml) and Et2O (20 ml).
3
4
2H, Ho, py, JH ꢀH =6.3 Hz, JH ꢀH =1.5 Hz), 8.08
o
4
o
m
p
(d, 1H, NꢁCHB, JHꢀH=2.1 Hz}, 7.57 (tt, 1H, Hp, py,
3JH ꢀH =7.5 Hz). 7.36 (dd, 1H, H6%, JH6%ꢀH5%=8.4 Hz,
3
p
4JH6%ꢀHm2%=1.8 Hz), 7.18 (dd, 2H, Hm, py), 7.15 (s, 1H.
H3), 7.08 (d, 1H, H2%), 6.57 (d, 1H, H5%, 5.85 (s, 1H, H6),
4.04 (m, 1H, NꢀC*H), 3.80 (s. 3H, OCH3), 3.77 (s, 3H,
OCH3), 3.74 (s, 3H, OCH3), 3.58 (s, 3H, OCH3), 3.30
(m, 1H, NꢀC*H), 2.63 (m, 1H, C6H10), 2.52 (m, 1H,
C6H10), 1.73 (m, 1H, C6H10), 1.46–1.20 (m, 4H, C6H10).
13C{1H}-NMR (CDCl3): l (ppm), 171.45 (NꢁCH),
166.16 (NꢁCH), 152.69, 151.64, 151.40, 150.18, 148.08,
146.99, 141.50, 138.13, 126,76, 125.60, 122.03, 115.09,
112.97, 112.31, 110.66 (C6H2+C6H3+NC5H2), 72.43,
68.49 (NC*H), 56.26 (2OMe), 56.08, 55.79 (OMe),
29.59, 29.44, 23.96, 23.81 (CH2 of C6H10).
Obtained: 0.187
g (83% yield). Anal. Calc. for
C24H29IN2O4Pd: C, 44.84; H, 4.55; N, 4.36. Found: C,
44.37; H, 4.75; N, 4.46%. IR (w, cm−1): 1642, 1588,
1543, 1520. Mass Spect. (FAB+) [m/z, (%)]: 641
(100%) [(MꢀH)+], 515 (100%) [(MꢀI)+]. 1H-NMR
4
(CD2Cl2): l (ppm), 8.42 (d, 1H, NꢁCHA, JHꢀH=1.8
4
Hz), 8.30 (d, 1H, H2%, JH2%ꢀH6%=1.8 Hz), 8.04 (d, 1H,
4
NꢁCHB, JHꢀH=2.1 Hz), 7.88 (s. 1H, H6), 7.57 (dd,
3
1H, H6%), JH6%ꢀH5%=8.4 Hz), 6.94 (s, 1H, H3), 6.93 (d,
1H, H5%, 4.07 (m, 1H, NꢀC*H), 4.06 (s. 3H, OCH3),
3.92 (s, 3H, OCH3), 3.87 (s, 3H, OCH3). 3.78 (s, 3H,
OCH3), 3.41 (m, 1H, NꢀC*H), 2.56 (m, 1H, C6H10),
2.35 (m, 1H, C6H10), 1.98(m, 2H, C6H10), 1.60–1.27 (m,
4H, C6H10). 13C{1H}-NMR (CD2Cl2): l (ppm), 168.86
(NꢁCH), 164.07 (NꢁCH), 153.42, 151.69, 150.77,
148.41, 146.37, 141.63, 126.82, 126.77, 125.52, 114.98,
111.82, 110.44 (C6H2+C6H3), 72.25 (NC*H), 69.18
(NC*H), 56.85, 56.44, 56.26, 56.21 (4OMe), 30.39,
29.79, 24.75, 24.43 (CH2 of C6H10).
4.9. Preparation of [Pd(C6H2-4,5-(OMe)2-2-CHꢁN-
(1R,2R)-C6H10ꢀNꢁCHꢀC6H3-3%,4%-(OMe)2-s-C,N,N)-
(p-NH2C6NO2)](ClO4) (7)
Complex 7 was obtained as described for 4. Complex
3 (0.150 g, 0.273 mmol) was reacted in acetone with
AgClO4 (0.057 g, 0.273 mmol) and 4-nitroaniline (0.084
g, 0.608 mmol) to give 7 as an orange solid. Obtained:
0.206 g (100% yield). Crystals of 7·0.6CH2Cl2 were
grown by vapor diffusion of Et2O into a CH2Cl2 solu-
tion of 7. The presence of solvent of crystallization was
checked by 1H-NMR. These crystals were used for
analytical and spectroscopic purposes. Anal. Calc. for
C30H35ClN4O10Pd·0.6CH2Cl2: C, 45.69; H, 4.54; N,
6.96. Found: C, 45.53; H, 4.69; N, 7.17%. IR (w, cm−1):
3372, 3250 (NH2), 1639, 1598, 1548, 1515 (NꢁC+
CꢁC), 1342, 1308 (NO2), 1086, 624 (ClO4). Mass Spect.
(FAB+) [m/z, (%)]: 515 (100%) [(MꢀClO4ꢀC6H6-
4.11. Preparation of [Pd(acac-O,O%)(C6H2-4,5-(OMe)2-
2-CHꢁN-(1R,2R)-C6H10ꢀNꢁCHꢀC6H3-3%,4%-(OMe)2-
s-C,N)] (9)
To a solution of 3 (0.200 g, 0.362 mmol) in CH2Cl2
(15 ml) Tl(acac) (0.148 g, 0.487 mmol) was added. After
30 min stirring, the suspension was filtered and the
resulting solution was evaporated to dryness, giving an

168
J. Bra6o et al. / Journal of Organometallic Chemistry 650 (2002) 157–172
oily residue. By addition of Et2O (10 ml) and continu-
ous stirring 9 was obtained as a yellow solid, which was
filtered and washed with Et2O (10 ml). Obtained: 0.160
g (72% yield). Crystals of 9·0.25CH2Cl2 were grown by
vapor diffusion of Et2O into a CH2Cl2 solution of 9.
The presence of solvent of crystallization was checked
Hz), 7.82 (dd, 1H, Hb phen), 7.04 (s, 1H, H3), 6.73 (dd,
3
4
1H, H6% JH6%ꢀH5%=8.1 Hz, JH6%ꢀH2%=2.1 Hz), 6.50 (d,
1H, H2%), 6.41 (d, 1H, H5%) 6.26 (s, 1H, H6), 4.04 (m,
1H, NC*H), 3.79, 3.71, 3.67 (3s, 9H, 3OMe), 3.43 (m,
1H, NC*H), 2.92 (s, 3H, OMe), 2.26 (m, 1H, C6H10),
1.97 (m, 1H, C6H10), 1.83(m, 4H, C6H10), 1.51 (m, 2H,
C6H10). 13C{1H)-NMR (CD2Cl2, 213 K): l (ppm),
175.67 (NꢁCH), 161.95 (NꢁCH), 151.32, 150.86, 149.93,
148.16, 146.98, 146.10, 144.97, 139.08, 130.39, 130.29.
128.84 (quaternary C atoms, C6H2+C6H3+phen),
152.26, 151.75, 139.93, 139.59, 128.54, 127.99, 126.69,
123.56, 115.06, 111.04, 111.00, 109.98, 107.22 (CH
atoms, C6H2+C6H3+phen), 77.72 (NC*H), 68.54
(NC*H), 56.44, 56.35, 56.28. 56.20 (4OMe), 34.35,
31.45, 25.81, 24.66 (CH2 of C6H10).
1
by H-NMR. These crystals were used for analytical
and spectroscopic purposes. Anal. Calc. for
C29H36N2O6Pd·0.25CH2Cl2: C, 55.21; H, 5.78; N, 4.40.
Found: C, 55.11; H, 6.02; N, 4.36%. IR (w, cm−1): 1640
(NꢁCH), 1588, 1515 (acac). Mass Spect. (FAB+) [m/z,
(%)]: 515 (100%) [(Mꢀacac)+]. 1H-NMR (CDCl3): l
(ppm), 8.42 (s, 1H, NꢁCHA), 7.67 (s, 1H, NꢁCHB), 7.24
4
(d, 1H, H2%, JH2%ꢀH6%=1.8 Hz), 7.10 (dd, 1H, H6%,
3JH6%ꢀH5%=8.4 Hz), 6.98 (s, 1H, H6), 6.76 (d, 1H, H5%,
6.66 (s, 1H, H3), 5.36 (s, 1H, CH, acac), 4.06 (m, 1H,
NꢀC*H), 3.88 (s, 3H, OCH3), 3.85 (s, 3H, OCH3), 3.83
(s, 3H, OCH3), 3.73 (s, 3H, OCH3), 3.35 (m, 1H,
NꢀC*H), 2.48 (m, 1H, C6H10), 2.04 (s, 3H, CH3, acac),
2.01 (s, 3H, CH3, acac), 1.93–1.71 (m, 7H, C6H10).
13C{1H}-NMR (CDCl3): l (ppm), 187.71 (CO, acac),
186.02 (CO, acac), 173.08 (NꢁCH), 161.42 (NꢁCH),
150.97. 150.13, 149.41, 148.93, 146.29, 136.84, 129.63,
122.69, 112.14, 110.36, 109.59, 109.41 (C6H2+C6H3),
99.96 (CH, acac), 74.55 (NC*H), 69.37 (NC*H), 56.06,
55.92, 55.88. 55.69 (4OMe), 33.46, 30.25, 24.80, 24.08
(CH2 of C6H10), 28.10, 27.69 (CH3, acac).
4.13. Preparation of [Pd(C6H2-4,5-(OMe)2-2-CHꢁN-
(1R,2R)-C6H10ꢀNꢁCHꢀC6H3-3%,4%-(OMe)2-s-C,N,N)-
(N-bipy)](ClO4) (11)
Complex 11 was obtained as described for 10. Com-
plex 3 (0.176 g, 0.32 mmol) was reacted in acetone with
AgClO4 (0.067 g, 0.32 mmol) and 2,2%-bipyridyl (0.050
g, 0.32 mmol) to give 11 as a yellow solid. Obtained:
0.238 g (97% yield). Anal. Calc. for C34H37ClN4O8Pd:
C, 52.93; H, 4.83; N, 7.26. Found: C, 52.57; H, 4.81; N,
7.17%. IR (w, cm−1): 1639, 1603, 1586, 1547, 1513.
Mass Spect. (FAB+) [m/z, (%)]: 671 (37%) [M+], 515
(100%) [(Mꢀbipy)+]. 1H-NMR (CD2Cl2, 213 K): l
4.12. Preparation of [Pd(C6H2-4,5-(OMe)2-2-
CHꢁN-(1R,2R)-C6H10ꢀNꢁCHꢀC6H3-3%,4%-(OMe)2-
s-C,N,N)(N-phen)](ClO4) (10)
3
(ppm), 9.21 (d, 1H, Ha bipy, JHꢀH=4.8 Hz), 8.61 (d,
3
1H, Ha bipy, JHꢀH=4.8 Hz), 8.12 (s, 1H, NꢁCH), 8.10
(s, 1H, NꢁCH), 8.07–8.01 (m, 3H, 2Hg+Hd bipy), 7.96
3
To a solution of 3 (0.200 g, 0.362 mmol) in acetone
(15 ml) AgClO4 (0.075 g, 0.362 mmol) was added in the
absence of light. After 30 min stirring, the suspension
was filtered and 1,10-phenanthroline (0.065 g, 0.362
mmol) was added to the freshly obtained solution. The
resulting yellow solution was stirred (r.t.) for 1 h, then
the solvent was evaporated to dryness and the oily
residue was treated with Et2O, giving 10 as a yellow
solid. This solid was filtered, washed with Et2O (20 ml)
and air dried. Obtained: 0.262 g (91% yield). Crystals of
10·0.5CH2Cl2 were grown by vapor diffusion of Et2O
into a CH2Cl2 solution of 10. The presence of solvent of
(d, 1H, Hd bipy, JHꢀH=7.8 Hz), 7.75 (t, 1H, Hb bipy),
7.49 (t, 1H, Hb bipy), 7.06 (s, 1H, H3), 7.02 (dd, 1H,
3
4
H6%, JH6%ꢀH5%=8.1 Hz, JH6%ꢀH2%=2.1 Hz), 6.80 (d, 1H,
H2%, 6.55 (d, 1H, H5%), 6.24 (s, 1H, H6), 3.78 (s, 3H,
OMe), 3.72 (s, br, 4H, OMe+NC*H), 3.68, 3.48 (2s,
6H, 2OMe), 3.34 (m, 1H, NC*H), 2.33 (m, 1H, C6H10),
1.86 (m, 3H, C6H10), 1.69–1.52 (m, 2H, C6H10), 1.39
(m, 2H, C6H10). 13C{1H}-NMR (CD2Cl2): l (ppm),
173.68 (NꢁCH), 163.16 (NꢁCH), 156.34, 151.98, 150.88,
148.92, 147.64, 140.13, 128.16, 122.99, 115.82, 112.33,
110.84, 110.66 (C6H2+C6H3), 151.83, 139.62, 126.65,
124.24 (CH atoms, bipy; the quaternary C atoms were
not observed), 75.33 (NC*H), 68.75 (NC*H), 56.54,
56.30, 56.23, 56.15 (4OMe), 32.62, 30.92, 25.18, 24.99
(CH2 of C6H10).
1
crystallization was checked by H-NMR. These crystals
were used for analytical and spectroscopic purposes.
Anal. Calc. for C36H37ClN4O8Pd·0.5CH2Cl2: C, 52.31;
H, 4.57; N, 6.68. Found: C, 52.39; H, 4.84; N, 6.48%.
IR (w, cm−1): 1636, 1586, 1546, 1516. Mass Spect.
(FAB+) [m/z, (%)]: 695 (70%) [M+], 515 (100%)
4.14. Preparation of [Pd(C6H2-4,5-(OMe)2-2-CHꢁN-
(1R,2R)-C6H10-NꢁCHꢀC6H3-3%,4%-(OMe)2-s-C,N)-
(dppe-P,P%)](ClO4) (12)
1
[(Mꢀphen)+]. H-NMR (CD2Cl2, 213 K): l (ppm), 9.66
(d, 1H, Ha phen, 3JHꢀH=4.8 Hz), 8.85 (d, 1H, Ha phen,
3
3JHꢀH=4.8 Hz), 8.71 (d, 1H, Hg phen, JHꢀH=8.1 Hz),
Complex 12 was obtained as described for 10. Com-
plex 3 (0.200 g, 0.362 mmol) was reacted in acetone
with AgClO4 (0.075 g, 0.362 mmol) and 1,2-bis-
(diphenylphosphino)ethane (dppe) (0.144 g, 0.362 mmol)
8.64 (d, 1H, Hg phen, 3JHꢀH=8.1 Hz), 8.23 (s, 1H,
NꢁCH), 8.21 (s, 1H, NꢁCH), 8.18 (dd, 1H, Hb phen),
3
8.11, 8.05 (AB spin system, 2H, 2Hd phen, JHꢀH=9.0

J. Bra6o et al. / Journal of Organometallic Chemistry 650 (2002) 157–172
169
to give 12 as an orange solid. Obtained: 0.352 g (96%
yield), Crystals of 12·0.3CH2Cl2 were grown by vapor
diffusion of Et2O into a CH2Cl2 solution of 12. The
amount of solvent of crystallization was checked by
1H-NMR. These crystals were used for analytical and
spectroscopic purposes. Anal. Calc. for C50H53-
ClN2O8P2Pd·0.3CH2Cl2: C, 58.13; H, 5.20; N, 2.69.
Found: C, 57.84; H, 5.38; N, 2.73%. IR (w, cm−1):
1640, 1605, 1585, 1549, 1511. Mass Spect. (FAB+)
[m/z, (%)]: 913 (37%) [M+], 515 (100%) [(Mꢀdppe)+].
1H-NMR (CDCl3): l (ppm), 8.41 (d, 1H, NꢁCH,
4JPꢀH=8.7 Hz), 8.23 (s, 1H, NꢁCH), 8.14 (m, 2H, Ho,
dppe), 7.86 (m, 2H, Ho, dppe), 7.63–7.43 [m, 15H,
H6%+(2Ho+8Hm+4Hp, dppe)], 7.31, 7.30 (2s, 2H,
H2%+H3), 7.26–7.18 (m, 2H, Ho, dppe), 6.83 (d, 1H,
Calc. for C6H14Cl2N2Pt: C, 18.95; H, 3.71; N, 7.36.
Found: C, 19.15; H, 3.53; N, 7.79%. IR (w, cm−1):
1
3278, 3188 (NH), 320, 313 (PtꢀCl). H-NMR (DMSO-
2
d6): l (ppm), 5.55 (d, 1H, NHaxial, JHꢀH=9.0 Hz), 5.03
2
(t, 1H, NHeq, JHꢀH$3JHꢀH=9.0 Hz), 2.11 (m, 1H,
NꢀC*H), 1.84 (m, 1H, C6H10), 1.43 (m, 1H, C6H10),
1.22 (m, 1H, C6H10), 0.95 (m, 1H, C6H10). Compound
13b. Anal. Calc. for C15H21ClO2N2Pt: C, 36.63; H, 4.30;
N, 5.69. Found: C, 36.35; H, 4.19; N, 5.73. IR (w,
cm−1): 3304, 3223 (NH2), 1610, 1590, 1580, 1537
(NꢁC+CꢁC), 319 (PtꢀCl). Mass Spect. (FAB+) [m/z,
1
(%)]: 492 (97%) [M+], 455(100%) [(MꢀCl)+]. H-NMR
3
(CDCl3): l (ppm), 7.10 (s, 1H, H6, C6H2, JPtꢀH=44
4
3
Hz), 6.99 (d, 1H, NꢁCH, JHꢀH=2.10 Hz, JPtꢀH=152
Hz), 6.53 (s, 1H, H3, C6H2), 4.45 (t, 1H, NH2,
2JHꢀH$3JHꢀH=10.8 Hz), 4.10 (m, 1H, NꢀC*H), 3.88
(s, 3H, OCH3), 3.77 (s, 3H, OCH3), 3.58 (d, 1H, NH2),
2.93 (m, 1H, NꢀC*H), 1.95 (m, 1H, C6H10), 1.87 (m,
1H, C6H10), 1.64 (m, 3H, C6H10), 1.22 (m, 1H, C6H10),
0.95 (m, 2H, C6H10). 13C{1H}-NMR (CDCl3): l (ppm)
166.08 (NꢁCH), 151.02, 144.90, 141.10, 140.21, 113.78,
111.00 (C6H2), 67.33, 63.31 (C*N, C6H10), 56.34, 55.89
(OCH3), 34.73, 30.92, 24.56, 24.00 (C6H10).
3
4
H5%, JH6%ꢀH5%=8.4 Hz), 5.95 (dd, 1H, H6, JPꢀH=8.7
4
Hz, JPꢀH=5.7 Hz), 3.89 (s, 3H, OMe), 3.79 (s, br, 4H,
OMe+NC*H), 3.62 (s, 3H. OMe), 3.55 (m, 1H,
NC*H), 2.83 (s, 3H, OMe), 2.10 (m, 2H, CH2, dppe),
1.85 (m, 2H, CH2, dppe), 1.56 (m, 1H, C6H10), 1.39(m,
1H, C6H10), 1.29–1.14 (m, 5H, C6H10), 0.04 (m, 1H,
C6H10). 31P{1H}-NMR (CDCl3): l (ppm), 60.85 (d,
3
dppe, JPꢀP=26.7 Hz), 40.61 (d, dppe). 13C{1H}-NMR
(CDCl3): l (ppm), 179.50 (NꢁCH): 161.76 (NꢁCH),
158.85 (d, JPꢀC=120 Hz), 151.12, 149.84 {dd, JPꢀC
=
4.16. Preparation of [Pt(Cl)(C6H2-4,5-(OMe)2-2-
CHꢁN-(1R,2R)-C6H10ꢀNꢁCHꢀC6H3-3%,4%-(OMe)2-
s-C,N,N)] (14)
10.3 Hz, JPꢀC=6 Hz), 149.00, 146.79, 142.08, 127.68,
122.74, 120.73 (dd, JPꢀC=11 Hz, JPꢀC=3.6 Hz), 112.90
(d, JPꢀC=120 Hz), 110.71, 109.78 (C6H2+C6H3),
135.15 (d, JPꢀC=13 Hz), 134.59 (d, JPꢀC=12.4 Hz),
133.47 (d, JPꢀC=12.4 Hz), 132.85 (d, JPꢀC=8.6 Hz)
(Cmeta, PPh2), 132.51, 132.35 (2C), 131.73 (Cpara, PPh2),
129.98 (d, JPꢀC=14 Hz), 129.84 (d, JPꢀC=14.8 Hz),
129.64 (d, JPꢀC=14.8 Hz), 129.49 (d, JPꢀC=15 Hz)
(Cortho, PPh2), 125.77 (JPꢀC=49 Hz), 125.43 (JPꢀC=36
Hz) (Cipso, PPh2, 2Cipso were not detected), 74.66, 72.36
(JPꢀC=4.5 Hz) (2NC*H), 56.14, 56.04, 55.87, 55.18
(4OMe), 33.96, 32.96, 24,87, 23.80 (CH2 of C6H10),
30.71 (dd, JPꢀC=35.6 Hz, JPꢀC=18.3 Hz, CH2, dppe),
27.56 (dd, JPꢀC=29.6 Hz, JPꢀC=9.5 Hz, CH2, dppe).
To a deoxigenated CHCl3 solution (15 ml) of [Pt(m-
Cl)(h3-2-MeꢀC3H4)]2 (0.200 g, 0.35 mmol), 1 was added
(0.287 g, 0.70 mmol). This solution was refluxed under
an Ar atmosphere for 5 h, then evaporated to dryness.
The oily residue was treated with Et2O (20 ml) giving
14 as an orange–red solid. Obtained: 0.191 g (42.6%
yield). Anal. Calc. for C24H29ClN2O4Pt: C, 45.04; H,
4.57; N, 4.38. Found: C, 44.63; H, 4.55; N, 4.40%. IR
(w, cm−1): 1681, 1631, 1598, 1537, 1520 (NꢁCH+
CꢁC), 290 (PtꢀCl). Mass Spect. (FAB+) [m/z, (%)]:
640 (55%) [M+], 604 (100%) [(MꢀCl)+]. 1H-NMR
(CDCl3): l (ppm), 8.77 (s, broad, 1H, NꢁCHA, 3JPtꢀH
=
4
4.15. Preparation of Cl2Pt[(NH2)2C6H10ꢀN,N%] (13a)
and [Pt(Cl)(C6H2-4,5-(OMe)2-2-CHꢁN-(1R,R)-
C6H10ꢀNH2-s-C,N,N)] (13b)
44 Hz), 8.38 (d, 1H, H2%, JH2%ꢀH6%=2.1 Hz), 8.21 (d,
1H, NꢁCHB, 4JHꢀH=2.1 Hz, 3JPtꢀH=147 Hz), 7.64 (dd,
3
3
1H, H6%, JH6%ꢀH5%=8.4 Hz), 7.22 (s, 1H, H6, JPtꢀH=48
Hz), 6.94 (s, 1H, H3), 6.91 (d, 1H, H5%), 4.06 (m, 1H,
NꢀC*H), 3.96 (s, 3H, OCH3), 3.89 (s, 3H, OCH3), 3.88
(s, 3H, OCH3), 3.76 (s, 3H, OCH3), 3.52 (m, 1H,
NꢀC*H), 2.54 (m, 1H, C6H10), 2.35 (m, 1H, C6H10),
1.93 (m, 2H, C6H10), 1.59–1.26 (m, 4H, C6H10).
13C{1H}-NMR (CDCl3): l (ppm), 168.41 (NꢁCH,
2JPtꢀC=113.2 Hz), 163.15 (NꢁCH), 153.56, 151.81,
148.62, 146.25, 140.58 (JPtꢀC=96.6 Hz), 138.59, 126.58,
PtCl2(DMSO)2 (0.2060 g, 0.488 mmol) was sus-
pended in 2-methoxyethanol (10 ml), and the bis-imine
1 (0.2004 g, 0.488 mmol) was added. This mixture was
heated at the reflux temperature for 22 h. After the
initial dissolution of the reactants a yellow solid begins
to precipitate. After the reaction time, the mixture was
allowed to reach r.t. and the yellow solid was filtered.
This solid was characterized as 13a. Obtained: 0.069 g
(37.1% yield based on Pt). The red alcoholic solution
was evaporated to dryness and the residue treated with
Et2O (15 ml), giving 13b as a red solid. Obtained: 0.044
g (18.3% yield based on Pt). Compound 13a. Anal.
126.01, 116.02 (JPtꢀC=68 Hz), 113.87, 112.05 (JPtꢀC
=
=
2
44 Hz), 110.50 (C6H2+C6H3), 74.65 (NC*H, JPtꢀC
48 Hz), 69.82 (NC*H, 2JPtꢀC=44 Hz), 56.52, 56.49,
56.25, 56.10 (4OMe), 30.27, 29.95, 24.87, 24.42 (CH2 of
C6H10).

170
J. Bra6o et al. / Journal of Organometallic Chemistry 650 (2002) 157–172
4.17. Catalytic Heck arylations of methylacrylate.
General procedure
The hydrogen atoms were placed in idealized positions
and treated as riding atoms, except for those of the
methyl group which were first located in a local slant-
Fourier calculation and then refined as riding atoms
with the torsion angles about the OꢀC(methyl) bonds
treated as variables. Each hydrogen atom was assigned
an isotropic displacement parameter equal to 1.2 times
the equivalent isotropic displacement parameter of its
parent atom. The chlorine atoms Cl4 and Cl6 of the
interstitial dichloromethane are disordered over three
equally populated positions. The structure was refined
to F2o, and 17 reflections were omitted in the least-
squares calculations [30]. Crystallographic calculations
were done on an ALPHASTATION (OPEN/VMS V6.2).
To a solution of the corresponding aryl halide (1.13
mmol) in dimethylacetamide (15 ml), methyl acrylate
(1.35 mmol), NEt3 (1.13 mmol) and the corresponding
catalyst (2 or 3, see amounts in Table 1) were added.
This mixture was refluxed under an Ar atmosphere for
24 h. Once cooled, water (10 ml) was added. The
organic phase was extracted several times with CH2Cl2
(3×10 ml) and the combined extracts were dried with
anhydrous MgSO4. The solvents were distilled off and
the residue was extracted with pentane. Evaporation of
the pentane solution gives the arylation products as
white solids or colorless oils (see Table 1 for yields).
4.18. Catalytic Heck hydroarylations of 2-norborene.
General procedures
5. Supplementary material
Crystallographic data for the structural analysis have
been deposited with the CCDC number 167181 for
compound 4b. Copies of this information may be ob-
tained free of charge from The Director, CCDC, 12
Union Road, Cambridge CB2 1EZ, UK (Fax: +44-
1223-336033; e-mail: deposit@ccdc.cam.ac.uk or http://
www.ccdc.cam.ac.uk).
To a solution of the appropriate aryl halide (5 mol)
in dimethylsulfoxide (10 ml), 2-norbornylene (15
mmol), NEt3 (15 mmol), HCO2H (10 mmol) and the
catalyst 3 (see amounts in Table 2) were added. This
mixture was heated at 90 °C under an Ar atmosphere
for 15 h. Once cooled, water (10 ml) was added. The
organic phase was extracted several times with pentane
(3×10 ml) and the combined extracts were dried with
anhydrous MgSO4. The solvents were distilled giving
the arylation products and colorless oils (see Table 2
for yields).
Acknowledgements
Funding by the Direccio´n General de Ensen˜anza
Superior e Investigacio´n Cient´ıfica (Spain, projects
PB98-1595-C02-01 and PB98-1593) is gratefully ac-
knowledged, and we thank Professor J. Fornies for
invaluable logistical support.
4.19. Crystal structure determination
Crystals of complex 4b CH2Cl2 of adequate quality
for X-ray measurements were obtained by slow evapo-
ration of CH2Cl2 solution of the crude complex 4b.
4.19.1. Data collection
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