Bonding in palladium(II) and platinum(II) allyl MeO-and H-MOP complexes. Subtle differences via13C NMR

Article abstract of DOI:10.1021/om049039t

¹³C NMR studies have shown that in both Pd(II)- and Pt(II)-allyl (modified-MOP) (MOP = (S)-2-diarylphosphino-1,1'-binaphthyl) complexes the substituent on the MOP auxiliary can affect how the naphthyl backbone interacts with a metal center. With the MeO-MOP analogue, the metal binds the carbon in a weak η¹-fashion, whereas with H-MOP it prefers an η²-binding mode. For the Pt complexes, the ¹J( ¹⁹⁵Pt,¹³C) values proved to be diagnostic tools. Both modes of bonding afford relatively weak bonds to the metal. Modifying the MOP ligand structure from a PPh₂ to a P(3,5-di-tert-butylphenyl) ₂ analogue can markedly affect the bond distances within the coordination sphere, as indicated by the X-ray structural data for PdCl(η³-C₃H₅(modified-MOP). 2-D NMR exchange spectroscopy can be used to recognize and distinguish between the two most common types of η³-η¹-η³ isomerization process, i.e., rotation around the allyl C-C bond versus rotation around the allyl M-C bond. For the complex PdCl(η³-C ₃H₅)(H-MOP), the fastest isomerization process involves rotation around the allyl C-C bond.

Full text of DOI:10.1021/om049039t

1306
Organometallics 2005, 24, 1306-1314
Bonding in Palladium(II) and Platinum(II) Allyl MeO-
13
and H-MOP Complexes. Subtle Differences via C NMR
P. G. Anil Kumar, Pascal Dotta, Rene´ Hermatschweiler, and Paul S. Pregosin*
Laboratory of Inorganic Chemistry, ETHZ, 8093 Zu¨rich, Switzerland
Alberto Albinati* and Silvia Rizzato
Department of Structural Chemistry (DCSSI and the Faculty of Pharmacy),
University of Milan, 20133 Milan, Italy
Received December 6, 2004
13C NMR studies have shown that in both Pd(II)- and Pt(II)-allyl (modified-MOP) (MOP
) (S)-2-diarylphosphino-1,1′-binaphthyl) complexes the substituent on the MOP auxiliary
can affect how the naphthyl backbone interacts with a metal center. With the MeO-MOP
analogue, the metal binds the carbon in a weak η1-fashion, whereas with H-MOP it prefers
1
an η2-binding mode. For the Pt complexes, the J(195Pt,13C) values proved to be diagnostic
tools. Both modes of bonding afford relatively weak bonds to the metal. Modifying the MOP
ligand structure from a PPh2 to a P(3,5-di-tert-butylphenyl)2 analogue can markedly affect
the bond distances within the coordination sphere, as indicated by the X-ray structural data
for PdCl(η3-C3H5)(modified-MOP). 2-D NMR exchange spectroscopy can be used to recognize
and distinguish between the two most common types of η3-η1-η3 isomerization process,
i.e., rotation around the allyl C-C bond versus rotation around the allyl M-C bond. For
the complex PdCl(η3-C3H5)(H-MOP), the fastest isomerization process involves rotation
around the allyl C-C bond.
Introduction
MOP ligands, introduced by Hayashi6-9 in connection
with the allylic alkylation7 and hydrosilylation6 reac-
tions, represent one of the more successful classes in
this area. The MAP ligand, a variation on MOP, with
R ) NMe2, has also been extensively studied.10
The subject of palladium-catalyzed reactions involving
allylic substrates continues to be of growing interest.1-5
Several reactions, e.g., allylic alkylation, involve the
generation of allyl intermediates, which have been
isolated and studied1-4 via X-ray diffraction and NMR
measurements.
Studies on the use of chiral monodentate phosphine
ligands6-11 in homogeneous catalysis are increasing. The
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76, 495-506. (b) Kollmar, M.; Helmchen, G. Organometallics 2002,
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There is some question as to whether these MOP
ligands are always complexed to the metal in a mono-
dentate fashion. Kocovsky and co-workers have
suggested10e that the complex [Pd(η3-C3H5)(MeO-MOP)]-
OTf contains an η2-coordinated olefin in which the two
Pd-C olefinic distances were observed to be 2.34 and
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L. F.; Ila, H.; Bell, H. P. Chem. Rev. 2004, 104, 3453-3516.
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A.; Tang, J.; Nohmi, K.; Mukaide, K.; Tsuji, H.; Uozumi, Y. Adv. Synth.
Catal. 2001, 343, 279-283. Hayashi, T.; Hirate, S.; Kitayama, K.; Tsuji,
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Hayashi, T. Tetrahedron Lett. 1998, 39, 8303-8306. Hayashi, T. Acta
Chem. Scand. 1996, 50, 259-266. Uozumi, Y.; Kitayama, K.; Hayashi,
T.; Kazunori, K.; Yanagi, K.; Fukuyo, E. Bull. Chem. Soc. Jpn 1995,
68, 713-722. Uozumi, Y.; Kitayama, K.; Hayashi, T. Tetrahedron
Asym. 1993, 4, 2419-2422.
(10) (a) Gouriou, L.; Lloyd-Jones, G. C.; Vyskocil, T.; Kocovsky, P.
J. Organomet. Chem. 2003, 687, 525-537. (b) Kocovsky, P.; Vyskocil,
S.; Smrcina, M Chem. Rev. 2003, 103, 3213-3245. (c) Fairlamb, I. J.
S.; Lloyd-Jones, G. C.; Stepan, V.; Kocovsky, P. Chem. Eur. J. 2002,
8, 4443-4453. (d) Lloyd-Jones, G. C.; Stephen, S. C.; Murray, M.; Butts,
C. P.; Vyskocil, S.; Kocovsky, P. Chem. Eur. J. 2000, 6, 4348-4357.
(e) Kocovsky, P.; Vyskocil, S.; Cisarova, I.; Sejbal, J.; Tislerova, I.;
Smrcina, M.; Lloyd-Jones, G. C.; Stephen, S. C.; Butts, C. P.; Murray,
M.; Langer, V. J. Am. Chem. Soc. 1999, 121, 7714-7715. (f) Kocovsky,
P.; Malkov, A. V.; Vyskocil, S.; Lloyd-Jones, G. C. Pure Appl. Chem.
1999, 71, 1425-1433. (g) Vyskocil, S.; Smrcina, M.; Kocovsky, P.
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Hanus, V.; Polasek, M.; Kocovsky, P. J. Org. Chem. 1998, 63, 7738-
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10.1021/om049039t CCC: $30.25 © 2005 American Chemical Society
Publication on Web 02/12/2005

Pd(II) and Pt(II) Allyl MeO- and H-MOP
Organometallics, Vol. 24, No. 6, 2005 1307
Scheme 2. Syntheses of Complexes 11-14
Scheme 1. Different Bonding Modes Exhibited by
the MOP Type Complexes
the synthesis of a few cationic Pd(II)- and Pt(II)-MOP
allyl complexes containing the modified MOP ligands
1a and 1b and their characterization in solution by
NMR studies. Several of these complexes display un-
expected bonding characteristics.
2.47 Å. Subsequently, several groups12-14 have shown
that these and related monodentate ligands can bind
in several ways as indicated in Scheme 1.
Results and Discussion
NMR Studies on [Pd (η3-C3H5)(MOP)] Com-
plexes. The syntheses of the Pd-allyl MOP complexes
were carried out via the bridge-splitting reactions on
the dinuclear complexes [PdCl(η3-C3H5)]2 with 2 equiv
of 1a or 1b to afford 11 and 13 (see Scheme 2).
Extraction of the chloride using NaBArF in CH2Cl2
solution leads to the cationic complexes [Pd(η3-C3H5)-
(1a)]BArF, 12, and [Pd(η3-C3H5)(1b)]BArF, 14. The 3,5-
di-tert-butyl phosphine derivatives were used, as they
(a) were available from previous catalytic studies14a and
(b) reduced the complexity of the aromatic region of the
proton spectra, thereby simplifying the assignment of
a number of naphthyl backbone protons.
Scheme 1 shows that differing MOP ligands can
function as a chelating P, C σ-donor (complexes 2, 3, 7,
8, and 10) or as a phosphine, π-olefin chelate (com-
pounds 5 and 6) and, reasonably enough, as a P, O
chelate via the O atom of the methoxy group, as in 9. It
was found that more than one naphthyl double bond
can be involved, as indicated in 5 and 6. All of these
complexes have been characterized via X-ray diffraction
and/or multinuclear NMR studies. Given our long-
standing interest in π-allyl chemistry,15 we considered
that the description of the [Pd(η3-C3H5)(MeO-MOP)]+
cation was still somewhat ambiguous. We report here
The various 1H resonances were assigned via 1H-
COSY and 31P,1H correlations as reported previously.15
One-bond and long-range 13C,1H correlations on the
(15) (a) Albinati, A.; Kunz, R. W.; Ammann, C.; Pregosin, P. S.
Organometallics 1991, 1800-1806. (b) Ammann, C. J.; Pregosin, P.
S.; Ruegger, H.; Albinati, A.; Lianza, F.; Kunz, R. W. J. Organomet.
Chem. 1992, 423, 415-430. (c) Pregosin, P. S.; Ru¨egger, H.; Salzmann,
R.; Albinati, A.; Lianza, F.; Kunz, R. W. Organometallics 1994, 13,
83-90. (d) Breutel, C.; Pregosin, P. S.; Salzmann, R.; Togni, A. J. Am.
Chem. Soc. 1994, 116, 4067. (e) Pregosin, P. S.; Ruegger, H.; Salzmann,
R.; Albinati, A.; Lianza, F.; Kunz, R. W. Organometallics 1994, 13,
5040-5048. (f) Abbenhuis, H. C. L.; Burckhardt, U.; Gramlich, V.;
Ko¨llner, C.; Pregosin, P. S.; Salzmann, R.; Togni, A. Organometallics
1995, 14, 759-766. (g) Pregosin, P. S.; Salzmann, R.; Togni, A.
Organometallics 1995, 14, 842. (h) Barbaro, P.; Pregosin, P. S.;
Salzmann, R.; Albinati, A.; Kunz, R. W. Organometallics 1995, 14,
5160-5170. (i) Kositzyna, N.; Antipin, M.; Lyssenko, K.; Pregosin, P.
S.; Trabesinger, G. Inorg. Chim. Acta 1996, 250, 335. (j) Pregosin, P.
S.; Salzmann, R. Coord. Chem. Rev. 1996, 155, 35-68.
(12) Wang, X. P.; Li, X.; Sun, J.; Ding, K. Organometallics 2003,
22, 1856-1862.
(13) Faller, J. W.; Sarantopoulos, N. Organometallics 2004, 23,
2008-2014.
(14) (a) Dotta, P.; Kumar, P. G. A.; Pregosin, P. S.; Albinati, A.;
Rizzato, S. Organometallics 2004, 23, 4247-4254. (b) Dotta, P.; Kumar,
P. G. A.; Pregosin, P. S.; Albinati, A. Helv. Chim. Acta 2004, 87, 272-
278. (c) Dotta, P.; Kumar, P. G. A.; Pregosin, P. S.; Albinati, A.; Rizzato,
S. Organometallics 2003, 22, 5345-5349.

1308 Organometallics, Vol. 24, No. 6, 2005
Kumar et al.
Table 1. 13C Chemical Shifts (in ppm) for the
Our observed 13C chemical shifts for carbons C-1 and
C-6 are in agreement with those reported by Kocovsky
et al., who find C-1 and C-6 to be at ca. 105 and 157
ppm, respectively. On the basis of these data, the
authors suggested that the Pd cation was, partially,
bound to the MOP in an η2-fashion. We believe that
these 13C data for 12 are more consistent with a weak
η1-bonding mode and suggest that their X-ray data, 2.34
and 2.47 Å for the Pd-C(1) and Pd-C(6) distances,
respectively, are consistent with this proposal. The 2.47
Å value is too long for a Pd-η2-olefin interaction,
whereas the 2.34 Å value is consistent with the η1-
bonding mode found in 7 and 8.14c
Complexes 11-14
11a
12b
13c
14a
position major/minor major/minor major major/minor
1
120.4/120.0
135.7/134.8
128.4/128.5
129.3/129.9
114.9/114.6
156.2/156.1
56.6/56.3
103.2/103.1
133.1/132.2
129.4/129.1
135.0/135.0
116.1/115.5
155.3/156.4
57.9/58.8
100.8/100.3
121.8/121.5
56.5/56.8
136.8
133.7
133.3
128.1
126.5
131.1
129.2/130.7
134.1/134.1
133.9/133.6
129.4/129.5
131.1/131.1
107.4/106.4
2
3
4
5
6
OCH3
L3
L2
L1
80.3/79.3
79.0
116.0
61.3
99.3/100.3
122.7/120.5
61.5/58.9
117.1/117.6
66.2/60.4
c
a Two isomers (major/minor) observed at 273 K. b223 K. 253
K, for the major isomer (500 MHz, CD2Cl2).
isolated allyl complexes were used to locate the key
naphthyl backbone carbon resonances via the assigned
protons, and selected 13C NMR results for these com-
plexes are shown in Table 1. Note that the allyl groups
can be either exo or endo with respect to the phosphine,
with the result that solutions of 11-14 each contain two
diastereomers. The carbon chemical shifts were as-
In contrast to 12, the H-MOP complex, 14, shows
modest coordination chemical shifts for both carbons,
ca. 8 ppm for C-1, δ ) 129.2, and ca. 24 ppm for C-6, δ
) 107.4. Note that, now, C-6, δ ) 107.4, and not C-1
has the lowest frequency. We believe these 13C NMR
data to be consistent with a weak, polarized complexed
π-bond.
NMR Studies on Pt-MOP Complexes. To
strengthen our arguments, we prepared related Pt-allyl
complexes using the same procedure as described for
the Pd analogues. Specifically, the cationic BArF com-
plexes, 17 and 18, were prepared from the neutral PtCl-
signed for both isomers in 11, 12, and 14, whereas for
13 only the major isomer was assigned. Since there is
not much difference in the chemical shifts between these
two different allyl isomers, only the data for the major
component will be discussed.
The fragments below show the 13C coordination
chemical shifts for the complexes 12 and 14.
(η3-allyl)(1a or 1b), 15 and 16, by extraction of chloride
with Na(BArF). These Pt derivatives are advantageous
in that they provide the coupling constants 1J(195Pt,13C).
The η3-[CH2C(CH3)CH2] allyl fragment was chosen, as
this simplifies the allyl spin system and hence makes
the Pt-C couplings easier to identify.
The chemical shift for the ipso carbon, C-1 in 12, δ )
103.2, has shifted to lower frequency by ca. 17 ppm
compared to the neutral chloro complex, 11. Interest-
ingly, there is no significant change in the 13C chemical
shift for the MeO-substituted carbon C-6, δ ) 155.3.
Moreover, the relative changes in the adjacent carbons
C-4 and C-5 are modest, so that there is no reason to
believe that these atoms are involved in further bonding.
The three allyl 13C positions are rather normal with
those pseudo-trans to phosphorus found at higher
frequency relative to those that are pseudo-trans to the
new bond.16 Interestingly, the allyl carbon pseudo-trans
to the P-donor shifts markedly to higher frequency on
going from the chloro complex to the cationic complex.
Table 2 gives the 13C chemical shifts for the key
carbons in 17 and 18. For the MeO-MOP analogue 17,
the signal for C-1 is found at 96.1 ppm and that for C-6
at 152.2 ppm. These chemical shifts are similar to those
found in 12. The values 1J(195Pt,13C-1) ) 109.2 Hz and
1J(195Pt,13C-6) ) 15.3 Hz are (a) quite different and (b)
relatively small. Figure 1 shows the long-range correla-
tion of protons H-5 and H-7 to C-1. Typical σ-bonded
ligands, e.g., a Pt-CH3 interaction, afford 1J(195Pt,13C)
values in the region of 350-700 Hz,17 so that the 15.3
Hz value seems more suggestive of a two-bond than a
(16) (a) Akermark, B.; Krakenberger, B.; S., H.; Vitagliano, A.
Organometallics 1987, 6, 620. (b) Malet, R.; Moreno-Manas, M.;
Pajuelo, F.; Parella, T.; Pleixats, R., Moreno-Manas, M. Magn. Reson.
Chem. 1997, 35, 227-236.
(17) Mann, B. E.; Taylor, B. F. 13C NMR Data for Organometallic
Compounds; Academic Press: London, 1981.

Pd(II) and Pt(II) Allyl MeO- and H-MOP
Organometallics, Vol. 24, No. 6, 2005 1309
Table 2. 13C Chemical Shifts (in ppm) for 17 and
18
17a
major/minor
18b
major/minor
position
1
96.1/95.8
137.4/137.3
128.0/127.2
136.0/137.0
117.7/116.3
152.2/156.0
57.2/57.3
116.1/118.7
132.6/132.0
132.8/132.2
129.9/129.7
131.9/132.5
95.0/96.1
2
3
4
5
6
OCH3
L3
L2
L1
89.0/89.5
89.4/92.4
24.2/23.0
54.5/49.4
23.9/22.7
46.8/45.5
1
1
1
a 17: JPt,C ) 109.2 (C1), JPt,C ) 15.3 (C6). b 18: JPt,C ) 89.0
1
(C1), JPt,C ) 56.1 (C6) (400 MHz, CD2Cl2).
Figure 3. ORTEP view of 13. Ellipsoids drawn at 50%
probability.
at phosphorus for monodentate ligands such as MOP
is not well known. Kocovsky has reported the structure
of [Pd(η3-C3H5)(MeO-MOP)]OTf, as well as the struc-
tures for several “Pd(MAP)” complexes.9e Hayashi has
determined the structure of PdCl(η3-CH2CHC(Me)2)-
(MeO-MOP), 19.8
Figure 1. 13C-1H HMBC NMR spectrum showing the
contacts from H-5 and H-7 to the ipso carbon C-1 in
complex 12.
Our modified MOP ligands contain 3,5-di-tert-butyl-
phenyl groups, which may affect how the various ligands
bond to palladium. Consequently, we have determined
the structure of one of our precursors, 13, and Figure 3
shows a view of this molecule. Selected bond angles and
bond distances are given in Table 3. The immediate
coordination sphere consists of the three allyl carbon
atoms, the MOP P-donor, and the chloride ligand. As
reported for 19, one of the two naphthyl rings is placed
over the plane defined by the Pd, P, and Cl atoms, in a
pseudo-fifth coordination position. Clearly, after the
chloride abstraction reaction, the naphthyl moiety is
well placed with respect to a possible interaction with
the palladium center. The disorder found for the allyl
ligand is a reflection of the two possible diastereomers
arising from the position of the allyl ligand.
Figure 2. One-bond 13C-1H correlation for the carbon C-6
in complex 14 showing the carbon signals for the two
isomers together with their 195Pt satellites.
one-bond interaction. Given that our observed
1J(195Pt,13C-1) in 17 of 109.2 Hz is small (compared to
350-700 Hz), the Pt-C bond in complex 17 must be
rather weak. It would seem that the MeO-MOP auxil-
iary in both the Pd- and Pt-allyl complexes prefers a
σ-coordination mode to the ipso carbon of the backbone,
albeit a weak σ-bond.
For the H-MOP complex 18, the 13C chemical shifts
for C-1 and C-6 are 116.1 and 95.0 ppm, respectively,
which are, again, similar to those observed in complex
14. Figure 2 shows a section of the one-bond 13C,1H
correlation indicating the carbons with 195Pt-satellites
from two different allyl isomers. Carbon C-6 now
possesses the lowest resonance frequency. The Pt-C
coupling constants, 1J(195Pt,13C-1) ) 89.0 Hz and
1J(195Pt,13C-6) ) 56.1 Hz, are relatively small, but of a
Two of the Pd-C allyl bond lengths, Pd-C1L and
Pd-C2L, are routine18a and are similar to those re-
ported by Kocovsky and Hayashi. However, the bond
length Pd-C3L, for the allyl carbon pseudo-trans to the
P atom, is somewhat short, 2.186(4) Å. The P-donor is
similar size, and suggest a weak π-bond. Typical 1J(195
-
Pt,13C) values in platinum olefin complexes, e.g., K[PtCl3-
(C2H4)], are on the order of 150 Hz.17
(18) (a) Orpen, A. G.; Brammer, L.; Allen, F. H.; Kennard, O.;
Watson, D. G.; Taylor, R. J. Chem. Soc., Dalton Trans. 1989, S1-S83.
(b) Farrar, D. H.; Payne, N. C. J. Am. Chem. Soc. 1985, 107, 2054-
2058.
X-ray Structure of 13. In contrast to the extensive
literature for chiral bidentate ligands, the configuration

1310 Organometallics, Vol. 24, No. 6, 2005
Kumar et al.
Table 3. Selected Bond Lengths (Å), Bond Angles
(deg), and Torsion Angles (deg) for 13
Pd-P(1)
2.328(1)
2.369(1)
2.136(4)
2.169(8)
2.186(4)
1.835(3)
1.827(3)
1.842(3)
1.367(8)
1.326(9)
1.510(4)
1.40(3)
Pd-Cl
Pd-C(1L)
Pd-C(2LB)
Pd-C(3L)
P(1)-C(6)
P(1)-C(121)
P(1)-C(111)
C(1L)-C(2LB)
C(3L)-C(2LB)
C(1)-C(1′)
<C-C>naphth
P(1)-Pd-Cl
93.19(4)
C(1L)-Pd-C(3L)
P(1)-Pd-C(1L)
P(1)-Pd-C(3L)
Cl-Pd-C(1L)
67.7(2)
105.0(1)
171.9(2)
161.8(1)
94.1(2)
Figure 4. Exchange spectrum for [PdCl(η3-C3H5)(MeO-
MOP)] at 273 K with a mixing time of 50 ms.
Cl-Pd-C(3L)
C(1L)-C(2LB)-C(3L)
Pd-P(1)-C(6)
126.6(8)
113.1(1)
104.3(1)
101.1(2)
terminal allyl carbon resonances are found at 78.0 and
61.6 ppm, respectively; that is, there is little difference
between these two.
Dynamic Studies on [PdCl(η3-C3H5)(MeO-MOP)].
It is well known15j,20-24 that allyl complexes are often
found to be dynamic on the NMR time scale, and this
is usually associated with η3-η1-η3 isomerization pro-
cesses.
C(6)-P(1)-C(111)
C(6)-P(1)-C(121)
C(111)-P(1)-C(6)-C(5)
C(121)-P(1)-C(6)-C(5)
C(6)-C(1)-C(1′)-C(6′)
10.7(3)
93.9(3)
94.4(4)
Scheme 3. Model PCy3,32 Biphemp,33 and
Oxazoline34 Pd Complexes
The 1H spectrum of the neutral [PdCl(η3-C3H5)(MeO-
MOP)] complex (without tert-butyl groups, as these
obscure several important allyl resonances) revealed a
series of broad signals for the allyl protons. On cooling
to 273 K, these resonances sharpen sufficiently to reveal
proton-proton and proton-phosphorus spin-spin in-
teractions. Figure 4 shows the phase-sensitive 1H-
NOESY at 273 K, with a mixing time of 50 ms. The
exchange cross-peaks connecting the two methoxy meth-
yl resonances (and those stemming from the central allyl
protons, CH2CHCH2) clearly indicate the exchange.
These exchange measurements were repeated using
several mixing times (50, 100, 200, and 600 ms), thereby
allowing an estimate of the exchange rate: 2.2 s-1(1)
(T1 relaxation times were around 500 ms). Further, with
a 50 ms mixing time, one finds selective syn/anti
exchange for the allyl methylene proton pairs trans to
the chloride ligand (see Figure 4). The syn and anti allyl
methylene protons trans to phosphorus do not exchange
positions on going from one isomer to the other. It is
well known that the η3-η1 isomerization mechanism can
expected to have a relatively strong trans influence, and,
consequently, values on the order of ca. 2.2 Å18b for this
Pd-C separation would have been normal. Scheme 3
shows Pd-C and Pd-P bond lengths from selected
model complexes.
Further, in 13, the observed distances Pd-P,
2.328(1) Å, and Pd-Cl, 2.369(1) Å, are relatively long.
The corresponding values in the MeO-MOP complex, 19,
are 2.310(1) and 2.304(4) Å. The model complexes in
Scheme 3 also indicate that a Pd-P separation of 2.31
Å, or less, might be expected. Perhaps there is some
steric crowding induced by the presence of the tert-butyl
groups. In agreement with steric congestion, we note
the slightly large P-Pd-Cl angle of ca. 93° (90° in 19).
We also note that there is a short contact, ca. 2.6 Å,
between the hydrogen on C122 (an ortho carbon of one
P-aryl) and the allyl carbon C1L. It appears that the
presence of the tert-butyl phenyl groups, within this
fairly simple molecule, can markedly affect the observed
bond lengths. This is surprising, but not completely
unexpected.19
(20) Faller, J. W. Determination of Organic Structures by Physical
Methods; Academic Press: New York, 1973; Vol. 5. Faller, J. W.;
Stokes-Huby, H. L.; Albrizzio, M. A. Helv. Chim. Acta 2001, 84, 3031-
3042. Faller, J. W.; Sarantopoulos, N. Organometallics 2004, 23, 2179-
2185.
(21) Cesarotti, E.; Grassi, M.; Prati, L.; Demartin, F.; Grassi, M. J.
Organomet. Chem. 1989, 370, 407-419. Cesarotti, E.; Grassi, M.; Prati,
L.; Demartin, F. J. Chem. Soc., Dalton Trans. 1991, 2073.
(22) (a) Gogoll, A.; Ornebro, J.; Grennberg, H.; Ba¨ckvall, J. E. J.
Am. Chem. Soc. 1994, 116, 3631. (b) Fernandez-Galan, R.; Jalon, F.
A.; Manzano, B. R.; Rodriguez de la Fuente, J.; Vreahami, M.; Jedlicka,
B.; Weissensteiner, W.; Jogl, G. Organometallics 1997, 16, 3758-3768.
(c) Mandal, S. K.; Gowda, G. A. N.; Krishnamurthy, S. S.; Zheng, C.;
Li, S. J.; Hosmane, N. S. Eur. J. Inorg. Chem. 2002, 2047-2056.
(23) Crociani, B.; Antonaroli, S.; Bandoli, G.; Canovese, L.; Visentin,
F.; Uguagliati, P. Organometallics 1999, 18, 1137-1147. Crociani, B.;
Benetollo, F.; Bertani, R.; Bombieri, G.; Meneghetti, F.; Zanotto, L J.
Organomet. Chem. 2000, 605, 28-38.
Interestingly, our 13C studies on the terminal allyl
carbons of complex 13 do not reflect what we find in
the solid state. The carbon pseudo-trans to the P-donor,
at 79.0 ppm, is found at much higher frequency than
that located pseudo-trans to chloride, 61.3 ppm. For a
related PPh3 complex, reported by Akermark,16a the two
(24) Sprinz, J.; Kiefer, M.; Helmchen, G.; Reggelin, M.; Huttner, G.;
Zsolnai, L. Tetrahedron Lett. 1994, 35, 1523-1526. Steinhagen, H.;
Reggelin, M.; Helmchen, G. Angew. Chem., Int. Ed. Engl. 1997, 36,
2108-2110.
(19) Dotta, P.; Kumar, P. G. A.; Pregosin, P. S. Magn. Reson. Chem.
2002, 40, 653-658.

Pd(II) and Pt(II) Allyl MeO- and H-MOP
Organometallics, Vol. 24, No. 6, 2005 1311
Scheme 4. Isomerization Mechanisms for the Allyl Fragment in the [PdCl(η3-C3H5)(MeO-MOP)] Complex
be under either electronic or steric control, and examples
of both have been reported.15j Apparently, in 13, the
former dominates,22b,c in that the allyl opens trans to
the P-donor to afford a Pd-C σ-bond trans to Cl.
Rotation around the sp3-sp2 C-C bond exchanges the
syn and anti protons trans to chloride ligand, and after
η1-η3 isomerization, the process is complete (see Scheme
4, top). These dynamics are in keeping with those
reported by Lloyd-Jones10d for a related Pd(MAP) com-
plex.
occupying syn positions pseudo-trans to the chloride (i.e.,
no syn/anti exchange, but positional exchange). We
believe that this slower process arises from both isomer-
ization of the “T”-shaped three-coordinate complex and
rotation around the M-C bond, as indicated in Scheme
4, bottom. Taken together, these 2-D NMR results
represent a rare example of the distinction between
these two mechanisms (rotation around the C-C bond
versus rotation around the M-C bond) via use of the
2-D exchange mixing time.
Interestingly, if one increases the mixing time to 600
ms, i.e., one waits longer, then new cross-peaks are
observed in the exchange spectrum at 273 K (see Figure
5). These new exchange peaks can be assigned to an
exchange process involving syn protons which were in
pseudo-trans position to the P-donor, but which are now
Comments. In conclusion, we have shown that in
both Pd(II)- and Pt(II)-allyl complexes the substituent
R on the MOP auxiliary can affect how the naphthyl
backbone interacts with a metal center. With the MeO-
MOP ligand, the metal binds the carbon in a weak η1-
fashion, whereas with H-MOP it prefers an η2-binding
mode. Both modes of bonding afford relatively weak
bonds to the metal. Although the nature of the MOP
ligand plays a role in these allyl compounds, Kocovsky
and co-workers have correctly recognizedsand our
various studies14 on cyclometalated MOP compounds,
among others, support this viewsthat a monodentate
description need not be correct for the coordination
chemistry of MOP and related ligands. The presence of
the 3,5-tert-butyl phenyl groups can affect the P-donor
capability as indicated by the solid-state structural data
for PdCl(η3-C3H5)(1b), in which the Pd-P bond is
relatively long (and thus one Pd-C(allyl) separation,
relatively short). Finally, one can distinguish between
two allyl isomerization mechanisms (rotation around the
C-C bond versus rotation around the M-C bond) via
use of several 2-D mixing times.
Figure 5. Comparison of sections of the two exchange
spectra for the two different mixing times. Note the
appearance of new cross-peaks in the lower slice with a
600 ms mixing time.

1312 Organometallics, Vol. 24, No. 6, 2005
Kumar et al.
Table 4. Experimental Data for the X-ray
Diffraction Study of 13
The standard deviations on intensities were calculated in
terms of statistics alone. The structure was solved by direct
and Fourier methods and refined by full matrix least squares,27
minimizing the function [∑w(Fo2 - (1/k)Fc2)2] and using aniso-
tropic displacement parameters for all atoms except for the
hydrogen atoms. In the difference Fourier maps two orienta-
tions for the allyl ligand were identified. Splitting the C2 atom
into two positions and refining the result using isotropic
temperature factors modeled the positional disorder. Moreover
some of the tert-butyl groups are disordered, as shown by the
values of the ADPs, possibly due to large-amplitude torsional
vibrations. No extinction correction was deemed necessary.
Upon convergence, the final Fourier difference map showed
no significant peaks.
formula
mol wt
data coll. T, K
diffractometer
cryst syst
space group (no.)
a, Å
C51H54ClPPd
839.76
293 (2)
Bruker SMART CCD
orthorhombic
P212121 (19)
10.2757(7)
20.044(1)
b, Å
c, Å
22.322(2)
V, Å3
4597.6(5)
Z
F
4
(calcd), g cm-3
1.213
µ, cm-1
5.28
radiation
Mo KR (graphite monochrom.,
λ ) 0.71073 Å)
2.41 < θ < 27.52
48 277
The contribution of the hydrogen atoms, in their calculated
position (C-H ) 0.95 (Å), B(H) ) 1.2 × B(Cbonded) (Å2)), was
included in the refinement using a riding model. Refining the
Flack’s parameter28 tested the handedness of the structure.
The scattering factors used, corrected for the real and imagi-
nary parts of the anomalous dispersion, were taken from the
literature.29 All calculations were carried out by using the PC
version of the programs WINGX,30 SHELX-97,27 and ORTEP.31
Synthesis of PdCl(η3-C3H5)(1a), 11. To a mixture of 1a
(100 mg, 0.144 mmol) and [Pd(µ-Cl)(η3-C3H5)]2 (26.4 mg, 0.072
mmol) was added 3 mL of CH2Cl2, and the resulting solution
was stirred for 60 min at room temperature. After removal of
the solvent, 4 mL of pentane was added to give a clear solution,
from which the product precipitated after a few minutes.
Yield: 112.9 mg (90%). Anal. Calcd for C52H62OPClPd: C,
71.31; H, 7.13. Found: C, 71.43; H, 7.06. 1H NMR (CD2Cl2,
θ range, deg
no. data collected
no. indep data
no. obsd reflns (no)
10 527
8033
2
2
[|Fo| > 2.0σ(|F| )]
no. of params refined (nv)
Rint
487
0.0590
0.0405
0.0900
1.029
0.03(2)
R (obsd reflns)a
Rw2 (obsd reflns)b
GOFc
absolute struct param
(Flack’s param)
2
2
a R ) ∑(|Fo - (1/k)Fc|)/∑|Fo|. b R2 ) [∑w(Fo - (1/k)Fc )2/
w
∑w|Fo | ]. c GOF ) [∑w(Fo - (1/k)Fc )2/(no - nv)]1/2
.
2 2
2
2
3
Experimental Section
500 MHz, 273 K): major isomer: δ 7.97 (d, JHH ) 8.1, H-4),
7.72 (d, 3JHH ) 8.1, H-10), 7.54 (H-5), 6.93 (d, 3JHH ) 8.2, H-7),
All water- or air-sensitive manipulations were carried out
under a nitrogen atmosphere. Pentane and ether were distilled
from NaK, THF and toluene from potassium, and CH2Cl2 from
CaH2. The MOP ligands were prepared according to literature
procedures.
NMR spectra were recorded with Bruker DPX-250, 300, 400,
and 500 MHz spectrometers at room temperature unless
otherwise noted. Chemical shifts are given in ppm; coupling
constants (J) in hertz. Elemental analyses and mass spectro-
scopic studies were performed at ETHZ.
3
4.96 (m, H-L2), 4.05 (t, JPH )3JHH ) 7.1, Hcis-L3), 3.91 (s,
3
3
OCH3), 2.00 (dd, JPH ) 11.2, JHH ) 14.1, Htrans-L3), 1.57
(Hcis-L1), 1.19 (s, C(CH3)3, 18 H), 1.16 (s, C(CH3)3, 18 H), 0.13
(d, J ) 12.2, Htrans-L1). Minor isomer: δ 7.94 (d, JHH ) 9.2,
3
H-4), 7.37 (d, JHH ) 9.7, H-5), 6.96 (H-7), 3.90 (Hcis-L3), 3.52
3
3
3
(s, OCH3), 3.38 (m, H-L2), 2.97 (dd, JPH ) 8.9, JHH ) 14.1,
Htrans-L3), 2.18 (d, JHH ) 5.9, Hcis-L1), 1.47 (d, JHH ) 12,
3
3
Htrans-L1), 1.21 (s, C(CH3)3, 18 H), 1.15 (s, C(CH3)3, 18 H). 13
C
NMR (CD2Cl2, 125 MHz, 273 K): major isomer: δ 156.2 (C-
6), 135.7 (C-2), 129.3 (C-4), 128.4 (C-3), 120.4 (C-1), 117.1 (C-
L2), 114.9 (C-5), 80.3 (C-L3), 66.2 (C-L1), 56.6 (OCH3), 35.2
(C(CH3)3), 31.5 (C(CH3)3). Minor isomer: δ 156.1 (C-6), 134.8
(C-2), 129.9 (C-4), 128.5 (C-3), 120.0 (C-1), 117.6 (C-L2), 114.6
(C-5), 79.3 (C-L3), 60.4 (C-L1), 56.3 (OCH3), 35.2 (C(CH3)3),
31.5 (C(CH3)3). 31P NMR (CD2Cl2, 202 MHz, 273 K): major
isomer: δ 12.6 (s). Minor isomer: δ 16.1 (s). MS(MALDI):
835.2 (M+ - C3H5, 100%).
Synthesis of [Pd(η3-C3H5)(1a)](BArF), 12. Complex 11
(68.9 mg, 0.079 mmol) and NaBArF (69.7 mg, 0.079 mmol)
were dissolved in 3 mL of CH2Cl2, and the resulting solution
was stirred for 30 min at room temperature. The NaCl formed
was removed by filtration over Celite and the solvent evapo-
rated in vacuo. Yield: 90 mg (67%). Anal. Calcd for C84H74-
OBF24PPd: C, 59.22; H, 4.38. Found: C, 59.40; H, 4.58. 1H
NMR (CD2Cl2, 500 MHz, 223 K): major isomer: δ 8.09 (d, 3JHH
Crystallography. Air-stable, yellow crystals of 13 suitable
for X-ray diffraction were obtained by crystallization from
dichloromethane/pentane. A prismatic single crystal of the
compound was mounted on a glass fiber at a random orienta-
tion. A Bruker SMART CCD diffractometer was used for the
space group determination and for the data collection. The
space group was determined from the systematic absences,
while the cell constants were refined at the end of the data
collection with the data reduction software SAINT.25 The
experimental conditions for the data collection, plus crystal-
lographic and other relevant data, are listed in Table 4 and in
the Supporting Information. The collected intensities were
corrected for Lorentz and polarization factors25 and empirically
for absorption using the SADABS program.26
3
) 9.2, H-4), 7.81 (d, JHH ) 9.2, H-5), 7.10 (H-7), 5.60 (m,
(26) Sheldrick, G. M. SADABS, Program for Absorption Correction;
University of Go¨ttingen: Go¨ttingen, Germany, 1996.
(27) Sheldrick, G. M. SHELX-97. Structure Solution and Refinement
Package; Universita¨t Go¨ttingen, 1997.
(28) Flack, H. D. Acta Crystallogr. 1983, A39, 876.
(29) International Tables for X-ray Crystallography; Wilson, A. J.
C., Ed.; Kluwer Academic Publisher: Dordrecht, The Netherlands,
1992; Vol. C.
(30) Farrugia, L. J. J. Appl. Crystallogr. 1999, 32, 837.
(31) Farrugia, L. J. J. Appl. Crystallogr. 1997, 30, 565.
(32) Fernandez-Galan, R.; Manzano, B. R.; Otero, A.; Lanfranchi,
M.; Pellinghelli. Inorg. Chem. 1994, 33, 2309-2312.
(33) Knierzinger, A.; Schoholzer, P. Helv. Chim. Acta 1992, 75, 1211.
(34) Schaffner, S.; Kueller, J. F. K.; Neuburger, M.; Zehnder, M.
Helv. Chim. Acta 1998, 81, 1223-1232.
(25) Bruker AXS, SAINT, Integration Software; Bruker Analytical
X-ray Systems: Madison, WI, 1995.

Pd(II) and Pt(II) Allyl MeO- and H-MOP
Organometallics, Vol. 24, No. 6, 2005 1313
3
H-L2), 3.71 (s, OCH3), 3.48 (d, JHH ) 4.8, Hcis-L1), 2.80 (dd,
[Pt(µ-Cl)(η3-C3H4(Me))]2 (70 mg, 0.123 mmol) was added 4 mL
of CH2Cl2, and the resulting solution was stirred for 60 min
at room temperature. After removal of the solvent, the product
was washed with 4 mL of pentane. Yield: 169 mg (91%). Anal.
Calcd for C37ClH32OPPt: C, 58.93; H, 4.28. Found: C, 58.79;
H, 4.48. 1H NMR (CD2Cl2, 500 MHz, 298 K): major isomer: δ
7.86 (3JHH ) 9.2, H-4), 7.26 (H-5), 3.80 (s, OCH3), 3.75 (bm,
Hcis-L3), 1.92 (4JHH ) 2.4, Hcis-L1), 1.88 (3JPH ) 10.1,
Htrans-L3), 1.76 (3JPtH ) 74.8, CH3-L2), 0.74 (2JPtH ) 75.4,4JHH
) 2.2, Htrans-L1). Minor isomer: δ 7.65 (3JHH ) 9.2, H-4), 6.91
(3JHH ) 9.2, H-5), 3.97 (bt, Hcis-L3), 3.58 (s, OCH3), 2.65 (m,
3JPH ) 9.4, Htrans-L3), 2.64 (Hcis-L1), 2.05 (3JPtH ) 71.7, CH3-
L2), 1.99 (Htrans-L1). 13C NMR (CD2Cl2, 125 MHz, 298 K):
major isomer: δ 155.6 (C-6), 135.0(C-2), 129.9 (C-4), 125.0 (C-
L2), 119.9 (C-1), 113.8 (C-5), 67.8 (C-L3), 55.8 (OCH3), 50.8
(C-L1), 23.4 (C(CH3)-L2). Minor isomer: δ 154.7 (C-6), 134.6
(C-2), 130.9 (C-4), 129.0 (C-3), 125.0 (C-L2), 119.3 (C-1), 112.3
(C-5), 66.9 (C-L3), 55.6 (OCH3), 49.5 (C-L1), 23.6 (C(CH3)-L2).
31P NMR (CD2Cl2, 202 MHz, 298 K): major isomer: δ 20.8 (s,
3JPH 9.9, JHH ) 14.6, Htrans-L3), 2.62 (bt, Hcis-L3), 2.37 (d,
3
)
3JHH ) 12.2, Htrans-L1), 1.18 (s, C(CH3)3, 18 H), 1.17 (s, C(CH3)3,
18 H). Minor isomer: δ 8.10 (d, 3JHH ) 9.2, H-4), 7.91 (d, 3JHH
3
3
) 9.2, H-5), 5.06 (m, H-L2), 3.86 (dd, JPH ) 10, JHH ) 14.8,
Htrans-L3), 3.79 (s, OCH3), 3.41 (d, 3JHH ) 4.9, Hcis-L1), 2.51 (d,
3JHH ) 12.3, Htrans-L1), 2.13 (bt, Hcis-L3), 1.18 (s, C(CH3)3, 18
H), 1.16 (s, C(CH3)3, 18 H). 13C NMR (CD2Cl2, 125 MHz, 223
K): major isomer: δ 155.3 (C-6), 135.0 (C-4), 133.1 (C-2), 129.4
(C-3), 124.6 (C-7), 121.8 (C-L2), 116.1 (C-5), 103.2 (C-1), 100.8
(C-L3), 57.9 (OCH3), 56.5 (C-L1), 35.4 (C(CH3)3), 31.4
(C(CH3)3). Minor isomer: δ 156.4 (C-6), 135.0 (C-4), 132.2 (C-
2), 129.1 (C-3), 124.5 (C-7), 121.5 (C-L2), 115.5 (C-5), 103.1
(C-1), 100.3 (C-L3), 58.0 (OCH3), 56.8 (C-L1), 35.4 (C(CH3)3),
31.4 (C(CH3)3). 31P NMR (CD2Cl2, 202 MHz, 223 K): major
isomer: δ 40.6 (s). Minor isomer: δ 40.2 (s). MS(ESI): 839.1
(M+ - BArF, 100%).
Synthesis of PdCl(η3-C3H5)(1b), 13. To a mixture of 1b
(100 mg, 0.151 mmol) and [Pd(µ-Cl)(η3-C3H5)]2 (27.6 mg, 0.075
mmol) was added 3 mL of CH2Cl2, and the resulting solution
was stirred for 40 min at room temperature. After removal of
the solvent, the product was washed with 4 mL of pentane.
Yield: 94 mg (74%). Anal. Calcd for C51H60PClPd: C, 72.42;
H, 7.15. Found: C, 72.32; H, 7.13. 1H NMR (CD2Cl2, 500 MHz,
253 K): major isomer: δ 7.87 (H-6), 7.83 (d, 3JHH ) 8.2, H-4),
1
1JPtP ) 4379). Minor isomer: δ 27.4 (s, JPtP ) 4364). ESI:
718.1 (M+ - Cl), 694.0, 662.0 (M+ - Cl, - C4H7), 633.0 (M+
Cl, - C4H7, - OMe), 618.0, 281.3 (M+ - MeO - MOP).
-
Synthesis of [PtCl(η3-C3H4(Me))(1b, Ar ) Ph)](BArF),
16. To a mixture of H-MOP (70 mg, 0.245 mmol) and [Pt(µ-
Cl)(η3-C3H4(Me))]2 (70 mg, 0.123 mmol) was added 4 mL of
CH2Cl2, and the resulting solution was stirred for 60 min at
room temperature. After removal of the solvent, the pale
orange product was washed with 4 mL of pentane. Yield: 158
mg (89%). Anal. Calcd for C36ClH30PPt: C, 59.71; H, 4.18.
Found: C, 60.29; H, 4.64. 1H NMR (CD2Cl2, 500 MHz, 298 K):
3
3
7.74 (d, JHH ) 8.4, H-10), 7.53 (dd, JHH ) 8.2 und 7.2, H-5),
7.24 (H-9), 6.86 (t, 3JHH ) 8.1, H-8), 6.81 (d, 3JHH ) 8.7, H-7),
4.86 (m, H-L2), 4.18 (dt, JHH ) 7.4, JPH ) 2.1, Hcis-L3), 2.86
3
3
(dd, JPH ) 10.2, JHH ) 13.3, Htrans-L3), 2.46 (d, JHH ) 6.3,
3
3
3
Hcis-L1), 1.14 (s, C(CH3)3, 18 H), 1.10 (s, C(CH3)3, 18 H), 0.99
(d, JHH ) 12.8, Htrans-L1). Minor isomer: δ 7.32 (H-5), 7.13
major isomer: δ 8.12-6.69 (aromatic), 3.82 (Hcis-L3), 2.74 (Hcis
-
3
(H-7), 4.56 (m, H-L2), 4.04 (dt, 3JHH ) 7.2, 3JPH) 1.6, Hcis-L3),
2.72 (d, 3JHH ) 6.6, Hcis-L1), 2.36 (dd, 3JPH ) 9.4, 3JHH ) 13.7,
Htrans-L3), 1.46 (d, 3JHH ) 12.0, Htrans-L1), 1.15 (s, C(CH3)3, 18
H), 1.11 (s, C(CH3)3, 18 H). 13C NMR (CD2Cl2, 125 MHz, 253
K): major isomer: δ 136.8 (C-1), 133.7 (C-2), 133.3 (C-3), 131.1
(C-6), 128.1 (C-4), 128.1 (C-10), 127.5 (C-7), 126.5 (C-5), 126.2
(C-9), 126.1 (C-8), 116.0 (C-L2), 79.0 (C-L3), 61.3 (C-L1), 35.3
L1), 2.02 (Htrans-L3), 2.01 (s, CH3-L2), 1.30 (Htrans-L1). Minor
isomer: δ 8.12-6.69 (aromatic), 3.97 (Hcis-L3), 2.47 (Htrans-L3),
2.37 (Hcis-L1), 1.89 (s, CH3-L2), 1.26 (Htrans-L1). 13C NMR (CD2-
Cl2, 125 MHz, 298 K): major isomer: δ 123.4 (C(CH3)-L2), 66.4
(C-L3), 47.9 (C-L1), 23.5 (C(CH3)-L2). Minor isomer: δ 123.8
(C(CH3)-L2), 67.1 (C-L3), 48.1 (C-L1), 23.2 (C(CH3)-L2). 31P
NMR (CD2Cl2, 202 MHz, 298 K): major isomer: δ 26.6 (s,1JPtP
) 4361). Minor isomer: δ 23.1 (s,1JPtP ) 4110). ESI: 688.1
(M+ - Cl), 632.1 (M+ - Cl, - allyl), 554,1 (M+ - Cl, - allyl, -
phenyl), 477.2 (M+ - Cl, - allyl, - 2 phenyl).
(C(CH3)3), 35.2 (C(CH3)3), 31.4 (C(CH3)3). Minor isomer:
δ
136.8 (C-1), 117.0 (C-L2), 79.2 (C-L3), 58.5 (C-L1), 35.3
(C(CH3)3), 35.2 (C(CH3)3), 31.4 (C(CH3)3). 31P NMR (CD2Cl2,
202 MHz, 253 K): major isomer: δ 18.5 (s). Minor isomer: δ
21.5 (s). MS(MALDI): 809 (M+ - Cl, 100%), 769 (M+ - C3H5
- Cl, 60%).
Synthesis of [Pt(η3-C3H4(Me))(1a, Ar ) Ph)](BArF), 17.
Complex 15 (74 mg, 0.098 mmol) and NaBArF (87 mg, 0.098
mmol) were dissolved in 4 mL of CH2Cl2, and the resulting
solution was stirred for 60 min at room temperature. The NaCl
formed was removed by filtration over Celite and the solvent
evaporated in vacuo. Yield: 130 mg (84%). Anal. Calcd for
C69H44OBF24PPt: C, 52.39; H, 2.80. Found: C, 52.19; H, 3.07.
1H NMR (CD2Cl2, 500 MHz, 298 K): major isomer: δ 8.03 (d,
3JHH ) 8.7, H-4), 7.81 (d, 3JHH ) 8.7, H-5), 6.99 (H-7), 3.48 (s,
OCH3), 3.38 (Hcis-L1), 2.22 (3JPH ) 8.3, Htrans-L3), 2.15
(Htrans-L1), 2.06 (Hcis-L3), 1.87 (3JPtH ) 71.0, CH3-L2). Minor
isomer: δ 8.06 (3JHH ) 8.8, H-4), 7.89 (3JHH ) 8.8, H-5), 3.58
Synthesis of [Pd(η3-C3H5)(1b)](BArF), 14. Complex 13
(50.0 mg, 0.059 mmol) and NaBArF (52.4 mg, 0.059 mmol)
were dissolved in 3 mL of CH2Cl2, and the resulting solution
was stirred for 30 min at room temperature. The NaCl formed
was removed by filtration over Celite and the solvent evapo-
rated in vacuo. Yield: 74.9 mg (67%). Anal. Calcd for C83H72-
BF24PPd: C, 59.57; H, 4.34. Found: C, 59.60; H, 4.60. 1H NMR
3
(CD2Cl2, 500 MHz, 273 K): major isomer: δ 8.12 (dd, JHH
)
3
6.4 and 8.9, H-5), 7.87 (H-4), 7.10 (H-7), 7.02 (d, JHH ) 6.4,
H-6), 5.70 (m, H-L2), 3.90 (bt, Hcis-L3), 3.60 (bd, JHH ) 6.4,
(s, OCH3), 3.27 (3JPH ) 8.2, Hcis-L3), 2.99 (Hcis-L1), 2.21 (Htrans
-
3
Hcis-L1), 2.76 (dd, JPH ) 9.7, JHH ) 14.8, Htrans-L3), 2.63 (d,
L1), 1.30 (Htrans-L3), 1.16 (3JPtH ) 68.0, CH3-L2). 13C NMR (CD2-
Cl2, 125 MHz, 298 K): major isomer: δ 152.2 (C-6), 137.4 (C-
2), 136.0 (C-4), 128.0 (C-3), 131.7 (C(CH3)-L2), 117.7 (C-5), 96.1
(1JPtC ) 109.2, C-1), 89.0 (C-L3), 57.2 (OCH3), 46.8 (C-L1), 23.9
(C(CH3)-L2). Minor isomer: δ 156.0 (C-6), 137.0 (C-4), 137.3
(C-2), 127.2 (C-3), 121.5 (C-L2), 116.3 (C-5), 95.8 (1JPtC ) 106.1,
C-1), 89.5 (C-L3), 57.3 (OCH3), 45.5 (C-L1), 22.7 (C(CH3)-L2).
31P NMR (CD2Cl2, 202 MHz, 298 K): major isomer: δ 40.0 (s,
3
3
3JHH ) 12.5, Htrans-L1), 1.21 (s, C(CH3)3, 36 H). Minor isomer:
3
δ 8.19 (dd, JHH ) 6.4 und 8.9, H-5), 7.86 (H-4), 7.15 (H-6),
5.01 (m, H-L2), 4.26 (dd, JPH ) 10, JHH ) 14.6, Htrans-L3),
3
3
3.48 (bd, JHH ) ca. 6.1, Hcis-L1), 3.15 (bt, Hcis-L3), 2.56 (d,
3
3JHH ) 12.5, Htrans-L1), 1.19 (s, C(CH3)3, 18 H), 1.15 (s, C(CH3)3,
18 H). 13C NMR (CD2Cl2, 125 MHz, 273 K): major isomer: δ
134.1 (C-2), 133.9 (C-3), 131.1 (C-5), 129.4 (C-4), 129.2 (C-1),
122.7 (C-L2), 107.4 (C-2), 99.3 (C-L3), 61.5 (C-L1), 35.3
(C(CH3)3), 31.3 (C(CH3)3). Minor isomer: δ 134.1 (C-2), 133.6
(C-3), 131.1 (C-5), 130.7 (C-1), 129.5 (C-4), 120.5 (C-L2), 106.4
(C-2), 100.3 (C-L3), 58.9 (C-L1), 35.3 (C(CH3)3), 31.3 (C(CH3)3),
31.2 (C(CH3)3). 31P NMR (CD2Cl2, 202 MHz, 273 K): major
isomer: δ 36.5 (s). Minor isomer: δ 36.2 (s). MS(ESI): 809.1
(M+ - BArF, 100%).
1
1JPtP ) 4093). Minor isomer: δ 40.1 (s, JPtP ) 4110). ESI:
718.1 (M+ - Cl), 694.0, 662.0 (M+ - Cl, - C4H7), 633.0 (M+
Cl, - C4H7, - OMe), 618.0.
-
Synthesis of [Pt(η3-C3H4(Me))(1b, Ar ) Ph)](BArF), 18.
[PtCl(η3-C3H4(Me))(H-MOP)], 16 (74 mg, 0.098 mmol), and
NaBArF (87 mg, 0.098 mmol) were dissolved in 4 mL of CH2-
Cl2, and the resulting solution was stirred for 60 min at room
temperature. The NaCl formed was removed by filtration and
the solvent evaporated in vacuo. Dissolving the solid in Et2O
Synthesis of [PtCl(η3-C3H4(Me))(1a, Ar ) Ph)], 15. To a
mixture of the MeO-MOP ligand (115 mg, 0.245 mmol) and

1314 Organometallics, Vol. 24, No. 6, 2005
Kumar et al.
and precipitation at -48 °C afforded a pale yellow solid.
Yield: 91 mg (80%), [Pt(η3-C3H4(Me))(H-MOP)](BArF). Anal.
Calcd for C68H42BF24PPt: C, 52.63; H, 2.73. Found: C, 52.04;
H, 2.86. 1H NMR (CD2Cl2, 500 MHz, 298 K): major isomer: δ
8.11 (dd, 3JHH ) 5.9 and 8.6, H-5), 7.71 (3JHH ) 8.6, H-4), 6.49
4071). ESI: 688.1 (M+), 631.9 (M+ - allyl), 554.9 (M+ - allyl,
- phenyl), 478.0 (M+ - allyl, - 2 phenyl).
Acknowledgment. P.S.P. thanks the Swiss Na-
tional Science Foundation and the ETH Zurich for
financial support. A.A. thanks M.I.U.R. for a research
grant (PRIN 2002). We also thank Johnson Matthey,
U.K., for the loan of precious metal salts.
(d, 3JHH ) 5.9, H-6), 3.40 (Hcis-L3), 3.40 (Hcis-L1), 2.44 (4JHH
)
2.2,2JPtH ) 73.3, Htrans-L1), 2.25 (3JPH ) 7.9, Htrans-L3), 1.88
(s,3JPtH ) 73.5, CH3-L2). Minor isomer: δ 8.18 (dd, 3JHH ) 6.1
and 8.6, H-5), 7.74 (3JHH ) 8.6, H-4), 6.57 (3JHH ) 6.1, H-6),
3.68 (3JPH ) 9.2, Hcis-L3), 2.99 (Hcis-L1), 2.17 (4JHH ) 3.4,
Supporting Information Available: Text giving experi-
mental details and a full listing of crystallographic data for
13, including tables of positional and isotropic equivalent
displacement parameters, anisotropic displacement param-
eters, calculated positions of the hydrogen atoms, bond dis-
tances, and bond angles. ORTEP figure showing the full
numbering schemes. X-ray data are also available as a CIF
file. This material is available free of charge via the Internet
at http://pubs.acs.org.
3
Htrans-L1), 2.02 (Htrans-L3), 1.02 (s, JPtH ) 69.5, CH3-L2). 13C
NMR (CD2Cl2, 125 MHz, 298 K): major isomer: δ 136.2
(C(CH3)-L2), 132.8 (C-3), 132.6 (C-2), 131.9 (C-5), 129.9 (C-4),
116.1 (1JPtC ) 89.0, C-1), 95.0 (1JPtC ) 56.1, C-2), 89.4 (C-L3),
54.5 (C-L1), 24.2 (C(CH3)-L2). Minor isomer: δ 132.8 (C(CH3)-
L2), 132.5 (C-5), 132.2 (C-3), 132.0 (C-2), 129.7 (C-4), 118.7
(1JPtC ) 76.0, C-1), 96.1 (1JPtC ) 48.6, C-2), 92.4 (C-L3), 49.4
(C-L1), 23.0 (C(CH3)-L2). 31P NMR (CD2Cl2, 202 MHz, 298 K):
major isomer: δ 35.8 (s,1JPtP ) 4075) isomer: δ 36.2 (s,1JPtP
)
OM049039T