Cationic palladium(II)-allyl-complexes containing 2-pyridyldiphenylphosphine: X-ray crystal structure of the binuclear complex [Pd(η3-2-Me-allyl)(μ-Ph2PPy)]2(BF4)2. Detection of an intramolecular C(allyl)-H?phenyl ring π-interaction

Article abstract of DOI:10.1016/j.jorganchem.2007.04.021

Reaction of [PdCl(η³-2-Me-allyl)(Ph₂PPy)] (1) with AgBF₄ affords the new dinuclear cationic complex [Pd(η³-2-Me-allyl)(μ-Ph₂PPy)]₂(BF₄)₂ (2). The X-ray structural analysis of 2 shows that the 2-pyridyldiphenylphosphine ligands adopt a binucleating role through the P and N atoms bridging two independent palladium centres to form an eight-membered metallocyclic ring. One of the anti hydrogen atoms of the allyl moiety was located very close to a phenyl ring of Ph₂PPy indicating the occurrence of a CH/π interaction. Addition of one equivalent of Ph₂PPy to complex (2) affords the mononuclear cationic complex [Pd(η³-2-Me-allyl)(Ph₂PPy)₂](BF₄) (3).

Full text of DOI:10.1016/j.jorganchem.2007.04.021

Journal of Organometallic Chemistry 692 (2007) 3577–3582
www.elsevier.com/locate/jorganchem
Note
Cationic palladium(II)-allyl-complexes containing
2-pyridyldiphenylphosphine: X-ray crystal structure of the
binuclear complex [Pd(g3-2-Me-allyl)(l-Ph2PPy)]2(BF4)2. Detection
of an intramolecular C(allyl)–Hꢀ ꢀ ꢀphenyl ring p-interaction
a,
b
c
a
a
a
A. Scrivanti *, F. Benetollo , A. Venzo , M. Bertoldini , V. Beghetto , U. Matteoli
a
`
Dipartimento di Chimica, Universita di Venezia, Calle Larga S. Marta 2137 – 30123 Venezia, Italy
b
I.C.I.S., CNR – Corso Stati Uniti 4 – 35127 Padova, Italy
c
I.S.T.M., CNR – Via Marzolo 1 – 35131 Padova, Italy
Received 9 February 2007; received in revised form 13 April 2007; accepted 13 April 2007
Available online 24 April 2007
Abstract
Reaction of [PdCl(g3-2-Me-allyl)(Ph2PPy)] (1) with AgBF4 affords the new dinuclear cationic complex [Pd(g3-2-Me-allyl)(l-
Ph2PPy)]2(BF4)2 (2). The X-ray structural analysis of 2 shows that the 2-pyridyldiphenylphosphine ligands adopt a binucleating role
through the P and N atoms bridging two independent palladium centres to form an eight-membered metallocyclic ring. One of the anti
hydrogen atoms of the allyl moiety was located very close to a phenyl ring of Ph2PPy indicating the occurrence of a CH/p interaction.
Addition of one equivalent of Ph2PPy to complex (2) affords the mononuclear cationic complex [Pd(g3-2-Me-allyl)(Ph2PPy)2](BF4) (3).
Ó 2007 Elsevier B.V. All rights reserved.
Keywords: Palladium; Palladium allyl complexes; 2-Pyridyldiphenylphosphine
1. Introduction
alous because 2-pyridyldiphenylphosphine is a potentially
P–N bidentate ligand which, for instance, in combination
with Pd(OAc)2 gives a highly efficient catalytic system for
alkyne carbonylation reactions [6,7].
We wish to report here the synthesis and the character-
ization of a novel cationic dinuclear g3-allyl–palladium
complex in which Ph2PPy bridges two independent palla-
dium atoms.
The chemistry of g3-allyl palladium complexes contin-
ues to receive much attention since they are used as
catalysts or catalyst precursors in several different catalytic
processes [1]. In particular, the chemistry of cationic
g3-allyl complexes has been deeply investigated because
these species are the key intermediates in asymmetric allylic
alkylation [2]. In this connection, it is worth to note that
even thought a wide range of ancillary ligands have been
used in order to direct and control the reactivity of the
Pd–allyl moiety, the studies dealing with palladium–allyl
complexes containing 2-pyridyldiphenylphosphine are rare
[3–5] and the chemistry of these species remains almost
unexplored. This lack of interest appears somehow anom-
2. Results and discussion
Complex [PdCl(g3-2-Me-allyl)(Ph2PPy)] (1) was syn-
thesised by reacting [PdCl(g3-2-Me-allyl)]2 with Ph2PPy
according to the literature [4]. Addition of one equivalent
of AgBF4 to a dichloromethane solution of 1 induces the
immediate precipitation of AgCl. Dilution of the filtrate
with diethyl ether leads to precipitation of the dinuclear
cationic complex 2 as a pale yellow powder (Scheme 1).
*
Corresponding author. Tel.: +39 0412348903; fax: +39 0412348967.
E-mail address: scrivanti@unive.it (A. Scrivanti).
0022-328X/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2007.04.021

3578
A. Scrivanti et al. / Journal of Organometallic Chemistry 692 (2007) 3577–3582
2
Pd
Ph2P
N
N
AgBF4
- AgCl
Ph2PPy
Ph2PyP
BF4
1/2
BF4
Pd
Pd
PPh2
PPyPh2
Ph2PyP
Cl
Pd
1
3
2
Scheme 1.
Single-crystals suitable for X-ray diffraction studies were
obtained by slow diffusion of diethyl ether into a dichloro-
methane solution of 2. The molecular structure of 2 is
shown in Fig. 1 and selected bond lengths and angles are
reported in Table 1.
metals are distorted square planar configurations with
C(11)–Pd(1)–C(13), N(1)–Pd(1)–P(1) angles of 67.7(5)°
and 96.5(2)°, and C(15)–Pd(2)–C(17), N(2)–Pd(2)–P(2)
angles of 67.2(4)° and 98.0(2)°, respectively. The allyl
ligands are bonded to the palladium atoms in asymme-
tric g3-fashion as indicated by the almost equal Pd(1)–
The X-ray analysis of complex 2 showed that 2-pyr-
idyldiphenylphosphine ligands adopt a binucleating role
through the P and N atoms bridging two independent pal-
ladium centres to form an eight-membered metallocyclic
ring. In fact, the distance between the two palladium atoms
˚
˚
C(12) (2.207(8) A), Pd(1)–C(13) (2.214(9) A), Pd(2)–C(16)
˚
˚
(2.211(8) A) and Pd(2)–C(17) (2.207(9) A) bond lengths,
which are significantly larger than the Pd(1)–C(11)
˚
˚
(2.132(8) A) and Pd(2)–C(15) (2.126(9) A) ones, while the
carbon–carbon bond lengths of the g3-allyl groups are
nearly equal (Table 1). The two methyl groups (C(14)
and C(18)) on the central atom are not in the same plane
of the other three carbon atoms and are bent towards the
˚
(3.944(8)) A is out of the range found for Pd–Pd bonds [8].
Examples of dinuclear palladium species in which two
Ph2PPy ligands bridge two Pd atoms in head-to-tail [8] or
in head-to-head [9] mode are known; however, to the best
of our knowledge, no example of cyclic species having no
palladium–palladium bond such as 2 has been previously
reported. The Pd(1)–Py–P(2) and Pd(2)–Py–P(1) moieties
are essentially planar, with a dihedral angle between the
two planes of 35.3(1)°. The orientations around the central
˚
palladium by a distance of 0.30(1) A from the C(11)–
C(12)–C(13) and C(15)–C(16)–C(17) planes, respectively,
as similarly observed for other palladium(II) derivatives
containing the g3-2-Me-allyl ligand [10]. The Pd(1)–P(1)
˚
˚
and Pd(2)–P(2) distances of 2.307(2) A and 2.295(2) A,
Fig. 1. Ortep view of the solid state structure of the dinuclear palladium complex 2. The broken lines show: (i) the interaction between the anti allyl proton
linked to C13 and the [C(37), C(38), C(39), C(40), C(41), C(42)] phenyl ring and, (ii) the close contact between the hydrogen atoms of C(18) methyl group
and the [C(31), C(32), C(33), C(34), C(35), C(36)] phenyl ring.

A. Scrivanti et al. / Journal of Organometallic Chemistry 692 (2007) 3577–3582
3579
Table 1
carbon atoms are coupled with two chemically but not
magnetically equivalent phosphorus atoms [9,11,12]. In
particular, as far as the carbon atoms of the allyl moiety
are concerned, it is worth to note that the signals due to
the central (at d 139.6) and the terminal carbon atoms trans
to the phosphorus (at d 81.1) are AXX0 multiplets, while
the resonance of the terminal carbon atoms cis to the phos-
phorus (at d 59.9) is a singlet. Furthermore, the 13C{1H}
NMR spectrum of 2 indicates that the eight-membered ring
is rigid showing two separate sets of resonances for the car-
bon atoms of the phenyl rings of the ligands. A detailed
˚
˚
Selected bond distances (A), angles (°) and non-bonding distances (A) for
[Pd2(g3-C4H7)2(Ph2PPy)2](BF4)2 (2)
Bond distances
Pd(1)–P(1)
Pd(1)–N(1)
Pd(1)–C(11)
Pd(1)–C(12)
Pd(1)–C(13)
P(1)–C(6)
2.307(2)
2.152(5)
2.132(9)
2.207(8)
2.214(9)
1.840(9)
1.37(1)
1.43(2)
1.42(2)
1.53(1)
Pd(2)–P(2)
Pd(2)–N(2)
Pd(2)–C(15)
Pd(2)–C(16)
Pd(2)–C(17)
P(2)–C(1)
2.295(2)
2.164(7)
2.126(9)
2.211(8)
2.207(9)
1.850(7)
1.35(1)
1.43(1)
1.42(1)
1.51(1)
N(1)–C(1)
N(2)–C(6)
C(11)–C(12)
C(12)–C(13)
C(12)–C(14)
C(15)–C(16)
C(16)–C(17)
C(16)–C(18)
1
analysis of the heterocorrelated H,13C-HMQC bidimen-
sional measurement allows to find all the aromatic proton
chemical shift values, confirming the magnetic non-equiva-
lence of the two phosphine phenyl rings (see Section 3 for a
comprehensive list of chemical shifts).
Bond angles
P(1)–Pd(1)–N(1)
P(1)–Pd(1)–C(11)
P(1)–Pd(1)–C(13)
N(1)–Pd(1)–C(11)
N(1)–Pd(1)–C(12)
N(1)–Pd(1)–C(13)
C(11)–Pd(1)–C(13)
Pd(1)–N(1)–C(1)
N(1)–C(1)–P(2)
96.5(2)
96.4(4)
161.0(3)
166.7(4)
129.3(4)
99.0(3)
P(2)–Pd(2)–N(2)
P(2)–Pd(2)–C(15)
P(2)–Pd(2)–C(17)
N(2)–Pd(2)–C(15)
N(2)–Pd(2)–C(16)
N(2)–Pd(2)–C(17)
C(15)–Pd(2)–C(17)
Pd(2)–N(2)–C(6)
N(2)–C(6)–P(1)
98.0(2)
95.6(3)
159.0(3)
166.2(3)
129.7(4)
99.0(4)
1
The H NMR spectrum of complex 2 displays, along
with the signals due to 2-pyridyldiphenylphosphine, five
separate resonances at d 3.91 (m), d 3.32 (s), d 2.92 (s), d
1.50 (s), and d 1.05 (d, JH,P = 10.1 Hz). These signals inte-
grate in the 2:2:2:6:2 ratio with respect to the phosphine
protons and are to be attributed to the protons of the
methallyl moiety (see Table 2).
67.7(5)
67.2(4)
125.3(4)
114.8(5)
116.1(9)
121.6(9)
121.3(9)
124.4(6)
116.9(6)
114.8(9)
122.7(9)
121.0(9)
C(11)–C(12)–C(13)
C(11)–C(12)–C(14)
C(13)–C(12)–C(14)
C(15)–C(16)–C(17)
C(15)–C(16)–C(18)
C(17)–C(16)–C(18)
In particular, in the NOESY experiment, dipolar corre-
lations with the CH3 resonance indicate that the signals at d
3.91 and d 3.32 are due to the two syn protons of the
Non-bonding distances
H(13A)ꢀ ꢀ ꢀQ(1)a
H(17A)ꢀ ꢀ ꢀQ(2)b
H(18B)ꢀ ꢀ ꢀQ(3)c
a
2.66(2)
2.80(6)
3.27(8)
1
methallyl group. Moreover, the H,13C-HMQC heteronu-
clear correlation measurement indicates that the hydrogen
atoms which resonate at d 3.91 and d 1.05 are linked to the
carbon atom resonating at d 81.1 and that the hydrogen
atoms whose signals occur at d 3.32 and d 2.92 are con-
nected to the carbon resonating at d 59.9. In keeping with
this findings, the signals at d 3.91 and d 1.05 are to be
attributed to Hc and Hd (see Fig. 3 for the allyl protons
numbering scheme), the syn hydrogen and the anti hydro-
gen trans to P, respectively; the signal at d 1.05 is an AA0X
multiplet since Hd couples with both phosphorus atoms as
confirmed by the fact that the resonance becomes a singlet
in the 1H{31P} NMR spectrum. Hence, the signals at d 3.32
and d 2.92 are to be attributed to Ha and Hb, the syn hydro-
gen and the anti hydrogen in cis position to phosphine
ligand: the close proximity between these protons and the
phosphorus atom was finally confirmed by 31P–1H HOESY
measurements. According to the above assignments, the
1H NMR spectrum of 2 looks very intriguing since the res-
onance of Hd as well as that of the methyl protons appear
markedly upfield (1.05 and 1.50 ppm, respectively) with
respect to the chemicals shifts usually found for this type
Q(1) is the centroid of the six-membered ring [C(37), C(38), C(39),
C(40), C(41), C(42)].
b
Q(2) is the centroid of the six-membered ring [C(19), C(20), C(21),
C(22), C(23), C(24)].
c
Q(3) is the centroid of the six-membered ring [C(31), C(32), C(33),
C(34), C(35), C(36)].
respectively, are normal for phosphine–palladium com-
plexes.
The head-to-tail coordination mode of the two P–N
ligands found in the solid state is retained in solution. In
fact, inspection of the 13C{1H} NMR spectrum of 2 reveals
that many resonances appear as second order AXX0 multi-
plets (see for instance Fig. 2) indicating that the relevant
Table 2
Chemical shifts of allyl protons in complexes 1–3a
Complex
CH3
Hb
Ha
Hd
Hc
1
2
3
a
1.96
1.50
1.89
2.76
2.92
3.21
3.06
3.32
3.82
3.56
1.05
3.21
4.48
3.91
3.82
Fig. 2. Section of the 13C NMR spectrum of complex 2 showing the
second order AXX0 multiplet due to the terminal allyl carbon atom trans
to the phosphorus atom.
In CD2Cl2 at 298 K.

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A. Scrivanti et al. / Journal of Organometallic Chemistry 692 (2007) 3577–3582
In order to ascertain the stability of the eight-membered
5Py
4Py
3Py
6Py
ring, complex 2 was treated with one equivalent of 2-pyr-
idyldiphenylphosphine. The reaction leads to selective brea-
king of the palladium–nitrogen bond affording in almost
quantitative yield the cationic complex 3 in which the two
Ph2PPy behave as monodentate P-donors (Scheme 1). In
C4
H
H
c
C
a
N
2
C
H
C3
1
b
2Py
H
d
P
1Ph
P
d
P
1
X
2Ph
4Ph
fact, in the proton allyl region, the H NMR spectrum of
3Ph
3 presents only three separate and sharp resonances cen-
tered at d 1.89 (s, CH3), d 3.21 (m, allyl anti protons) and
d 3.82 (br s, allyl syn protons) in keeping with the presence
of a symmetry plane bisecting the allyl moiety. The equiv-
alence of the two phosphorus atoms is confirmed by the
31P NMR spectrum of 3 which consists of a singlet at d
26.4. Conclusive evidence for the symmetrical structure of
3 is given by the 13C NMR spectrum where the terminal
allyl carbon atoms appear as the A part of an AXX0 spin
system, while the central carbon atom is an 1:2:1 triplet
owing to the coupling with two equivalent phosphorus
atoms.
Fig. 3. Numbering scheme for the allyl moiety and Ph2PPy.
of hydrogen atoms in other cationic [Pd(g3-allyl)(P–N)]+
1
complexes [13–16] (compare also with the H NMR data
for complexes 1 and 3 reported in Table 2). Anomalous
1H upfield shifts generally occur when proton nuclei reside
in a strongly shielding zone, e.g. over the ring currents of
an aromatic moiety.
Accordingly, inspection of the crystal structure of 2
reveals that the structure of the dinuclear dication forces
the allyl ligand close to the phenyl rings of the P-ligand
and that the anti-H(13A) proton is located at a very short
The allyl moiety of complex 3 appears to be rigid and no
sign of dynamic behaviour was detected by NMR spectros-
copy at room temperature.
˚
distance, viz., 2.66(2) A, from the centroid of the [C(37),
C(38), C(39), C(40), C(41), C(42)] ring (see Fig. 1). Simi-
larly, the distance between H(17A) and the centroid of
the [C(19), C(20), C(21), C(22), C(23), C(24)] ring is
3. Experimental
˚
2.80(6) A. Such short distances are significantly smaller
Reactions were performed under argon atmosphere
using standard Schlenk techniques. Solvents (J.T. Baker)
were purified as described in the literature [19]. 2-Pyridyldi-
phenylphosphine was purchased from Aldrich. [PdCl(g3-2-
Me-allyl)]2 [20] and [PdCl(g3-2-Me-allyl)(Ph2PPy)] [4] were
prepared according to the literature.
than the sum of the relevant van der Waals radii [17]. In
the last decade several examples of such close CH/p con-
tacts have been reported in organometallic and coordina-
tion chemistry and it is generally accepted that these
interactions are attractive, albeit weak [17]. Although this
kind of interaction is not rare in organometallic com-
pounds [17], the present case is worthy of note because it
involves a terminal hydrogen atom of an allyl moiety.
The close proximity of Hd to the phenyl ring found in
the solid state structure is retained in solution as confirmed
by its above-mentioned ring current induced anomalous
chemical shift and also by the NOESY experiment in which
the anti proton Hd exhibits a NOE contact with the protons
of the phenyl at d 7.655.
1H, 13C and 31P NMR spectra were obtained as CDCl3 or
CD2Cl2 solutions on a Bruker DRX-400 spectrometer oper-
ating at 400.13, 100.61 and 161.98 MHz, respectively, and
equipped with a BVT2000 temperature controller. The
chemical shift values are given in d units with reference to
internal Me4Si for 1H and 13C, and to external 85% H3PO4
for 31P. Suitable integral values for the proton spectra were
obtained by a pre-scan delay of 10 s to ensure a complete
relaxation for all the resonances. The proton assignments
were performed by standard chemical shift correlations as
well as by 2D COSY, TOCSY, and NOESY experiments.
The 13C chemical shift values were assigned through 2D-
heteronuclear correlation experiments (heteronuclear multi-
ple quantum correlation, HMQC, with bilinear rotation-
decoupling, BIRD, sequence [21] and quadrature along F1
achieved using the time-proportional receiver phase incre-
mentation, TPPI, method [22] for the H-bonded carbon
atoms, and heteronuclear multiple bond correlation, HMBC
[23] for the other 13C nuclei).
A very similar situation was found [18] in the case of
anti-homo-bimetallic complexes of 2,7-dimethyl-as-inda-
cene-diide with two Rh(cyclo-octa-1,5-diene)2 or Ir(cyclo-
octa-1,5-diene)2 groups, where an olefinic proton of the
˚
coordinated cycloolefin is located at about 2.5–2.7 A above
an arene ring and its resonance undergoes a comparable
1
upfield shift in the H NMR spectrum.
The anomalous upfield shift of the resonance of the
methyl protons of the methallyl units may be similarly jus-
tified taking into account the ring current effect due to the
proximity of the CH3 group bearing the H(18A), H(18B)
and H(18C) hydrogens to the centroid of the [C(31),
C(32), C(33), C(34), C(35), C(36)] phenyl ring found in
the crystal structure (Fig. 1), e.g. this distance for H(18B)
3.1. [PdCl(g3-2-CH3-C3H4)(Ph2PPy)] (1)
A solution of 2-pyridyldiphenylphosphine (670 mg,
2.56 mmol) in dichloromethane (20 mL) was added drop-
wise to a solution of [Pd(g3-2-CH3-C3H4)Cl]2 (500 mg,
1.28 mmol) in dichloromethane (20 mL). The resulting
˚
is 3.27(8) A. Accordingly, a NOE contact was observed
between the methyl resonance and the aromatic protons
at d 7.410.

A. Scrivanti et al. / Journal of Organometallic Chemistry 692 (2007) 3577–3582
3581
solution was stirred for 1 h, then concentrated under
reduced pressure. Addition of diethyl ether caused the pre-
cipitation of complex 1 as a white solid (1.10 g, 95% yield).
1H NMR (CD2Cl2): d = 1.96 (s, 3H, CH3), 2.76 (s, 1H, Hb
anti), 3.06 (s, 1H, Ha syn), 3.56 (d, 1H, Hd anti,
JH,P = 9.9 Hz), 4.48 (m, 1H, Hc syn, JH,P = 6.7 Hz), 7.34
(m, 1H, H-5Py), 7.36–7.55 (m, 6H, arom), 7.64–7.80 (m,
6H, arom), 8.75 (m, 1H, H-6Py, JH-5Py,H-6Py = 5.0 Hz).
31P{1H} NMR (CD2Cl2): d = 26.0 (s). 13C NMR (CDCl3)
d = 157.7 (d, C-2Py, JC,P = 61.5 Hz), 150.2 (d, C-6Py,
JC,P = 14.8 Hz), 135.9 (d, C-4Py, JC,P = 8.7 Hz), 134.3 (d,
C-2Ph, JC,P = 13.2 Hz), 132.9 (d, C-2all, JC,P = 4.9 Hz),
132.0 (d, C-1Ph, JC,P = 42.3 Hz), 130.4 (s, C-4Ph), 130.0
(d, C-3Py,JC,P = 25.2 Hz), 128.5 (d, C-3Ph, JC,P = 10.4
Hz), 123.8 (s, C-5Py), 78.0 (d, C-3all, JC,P = 32.4 Hz),
61.3 (s, C-1all), 23.2 (s, C-4all).
(CD2Cl2): d = 156.9 (AA0X m, 2C, C-2Py), 150.6 (AA0X
m, 2C, C-6Py), 138.2 (t, 1C, C-2all, JC,P = 4.9 Hz), 136.6
(AA0X m, 2C, C-4Py), 134.0 (AA0X m, 8C, C-2Ph), 131.4
(d, 4C, C-4Ph, JC,P = 9.9 Hz), 130.9 (AA0X m, 4C,
C-1Ph), 129.1 (AA0X m, 8C, C-3Ph), 128.0 (AA0X m,
2C, C-3Py), 124.8 (s, 2C, C-5Py), 76.91 (AA0X m, 2C,
C-1all and C-3all), 23.4 (C-4all). Anal. Calc. for C38-
H36BF4N2P2Pd: C, 58.82; H, 4.68. Found: C, 58.79; H,
4.62%.
3.4. X-ray measurements and structure determination
Crystal
data
for
{[Pd2(g3-C4H7)2(Ph2PPy)2]2+
[(BF4)2]2ꢁ} Æ H2O (2). C42H42P2N2B2F8OPd2: M =
˚
1041.18, monoclinic, space group Cc, a = 11.501(2) A,
˚
˚
b = 26.360(3) A, c = 16.581(3) A, b = 92.42(3)°, V =
3
5022(1) A , Z = 4, Dc = 1.374 g cmꢁ3
,
k(Mo Ka) =
˚
3.2. [Pd2(g3-2-CH3-C3H4)2(l-Ph2PPy)2](BF4)2 (2)
˚
0.71073 A, l(Mo Ka) = 8.40 mmꢁ1, F(000) = 2088.
Crystal was lodged in Lindemann glass capillary and cen-
tered on a four circle Philips PW1100 diffractometer using
To a solution of 1 (500 mg, 1.10 mmol) in dichlorometh-
ane (20 mL) was added dropwise a solution of AgBF4
(210 mg, 1.10 mmol) in CH3OH (5 mL). The resulting sus-
pension was stirred for 1 h at room temperature, then fil-
tered to eliminate AgCl. Addition of diethyl ether to the
filtrate caused the precipitation of complex 2 as a pale yel-
low solid (512 mg, yield 92%). 1H NMR (CD2Cl2): d = 1.05
(d, 2H, Hd anti, JH,P = 10.1 Hz), 1.50 (s, 6H, CH3), 2.92 (s,
2Hb anti), 3.32 (m broad, 2Ha syn), 3.91 (m, 2Hc syn,
JH,P = 2.8 Hz), 7.31–7.48 (m, 3H, arom), 7.50–7.65 (m,
4H, arom), 7.68–7.87 (m, 4H, arom), 9.00 (d, 2H, H-
6Py, JH-5Py,H-6Py = 5.1 Hz). 31P{1H} NMR (CD2Cl2): d =
˚
graphite monochromated Mo Ka radiation (0.71073 A),
following the standard procedures at room temperature.
All intensities were corrected for Lorentz polarization and
absorption [24].
The structures were solved by standard direct methods
[25]. Refinement was carried out by full-matrix least-
2
squares procedures (based on Fo ) using anisotropic tem-
perature factors for all non-hydrogen atoms. Hydrogen
atoms were introduced in calculated positions in their
described geometries and during refinement were allowed
to ride on the attached carbon atoms with fixed isotropic
thermal parameters (1.2Uequiv) of the parent carbon atom.
13
27.27 (s). C{1H} NMR (CD2Cl2): d = 158.2 (AA0X m,
1C, C-2Py), 155.6 (AA0X m, 1C, C-6Py), 139.6 (AA0X m,
1C, C-2all), 139.1 (AA0X m, 1C, C-4Py), 137.0 (AA0X m,
2C, C-2Ph), 134.8 (AA0X m, 1C, C-4Ph), 132.8 (AA0X
m, 2C, C-2Ph), 132.4 (AA0X m, 1C, C-4Ph), 131.3 (AA0X
m, 2C, C-3Ph), 131.1 (d, 1C, JC,P = 5 Hz, C-3Py), 130.5
(AA0X m, 2C, C-3Ph), 129.8 (AA0X m, 1C, C-1Ph),
126.7 (s, 1C, C-5Py), 125.7 (AA0X m, 1C, C-1Ph), 81.1
(AA0X m, 1C, C-3all), 59.9 (s, 1C, C-1all), 22.3 (s, 1C,
C-4all). Anal. Calc. for C42H42B2F8N2P2Pd2: C, 49.30; H,
4.14. Found: C, 49.10; H, 4.10%.
The Flack parameters [26] have been refined for the struc-
P
ture. For a total of 533 parameters, wR0 = [ w(Fo ꢁ Fc2)2/
2
P
w(Fo2)2]1/2 = 0.128, S = 1.182, and conventional R =
0.047, based on the F values of 6023 reflections having
I P 2 r(I). Structure refinement and final geometrical cal-
culations were carried out with SHELXL-97 [27] program,
implemented in the WinGX package [28].
4. Supplementary material
CCDC 635915 contains the supplementary crystallo-
graphic data (excluding structure factors) for this paper.
These data can be obtained free of charge via http://
www.ccdc.cam.ac.uk/conts/retrieving.html, or from the
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or
e-mail: deposit@ccdc.cam.ac.uk.
3.3. [Pd(g3-2-CH3-C3H4)(Ph2PPy)2]+(BF)4 (3)
ꢁ
A solution of 2-pyridyldiphenylphosphine (307 mg,
1.17 mmol) in dichloromethane (20 mL) was added to a
solution of 2 (600 mg, 0.58 mmol) in dichloromethane
(30 mL). The resulting solution was stirred for 1 h at room
temperature then concentrated to small volume under
reduced pressure. Addition of diethyl ether afforded com-
plex 3 as a pale yellow solid (720 mg, 80% yield).
1H NMR (CD2Cl2): d = 1.89 (s, 6H, CH3), 3.21 (AA0XX0
m, 4H, Hanti), 3.82 (br s, 4H, Hsyn), 7.06 (d, 2H, H-3Py,
JH-3Py,H-4Py = 8.0 Hz), 7.20 (m, 2H, H-5Py), 7.28–7.54 (m,
22 Harom), 8.44 (d, 2H, H-6Py, JH-5Py,H-6Py = 4.5 Hz).
31P{1H} NMR (CD2Cl2): d = 26.4 (s). 13C{1H} NMR
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