Structural and13C NMR studies on palladium MOP compounds: A new weak C-Pd σ-bond plus MOP as a bridging diene ligand

Article abstract of DOI:10.1021/om0496535

A new set of Pd-MOP complexes (MOP = (S)-2-diarylphosphino-1,1′-binaphthyl) has been prepared. One of these, containing MeO-MOP (=2-(diphenylphosphino)-2′-methoxy-1,1′-binaphthyl), is shown to act as a chelating ligand with a naphthyl backbone diene bridging a Pd(I)-Pd(I) bond. This bonding mode exists in both the solid and solution states. A series of chloro-Pd(II)MOP complexes containing the well-known cyclometalated N,N- dimethyl benzylamine chelate have been treated with NaBArF to extract the chloride ligand. The products, starting from the H-MOP, MeO-MOP, and NC-MOP analogues, are all different. Of particular interest is the product from the H-MOP reaction in that the fourth coordination position is occupied by a weak Pd-C a-bond from the naphthyl backbone, on the basis of¹³C NMR data. The rate of product formation in the Pd-catalyzed hydrosilylation of styrene with SiHCl₃has been measured as a function of time for the four auxiliaries H-MOP, MeO-MOP, HO-MOP, and NC-MOP. The NC-MOP is shown to be much faster than the others, and a tentative explanation is offered.

Full text of DOI:10.1021/om0496535

Organometallics 2004, 23, 4247-4254
4247
Str u ctu r a l a n d 13C NMR Stu d ies on P a lla d iu m MOP
Com p ou n d s: A New Wea k C-P d σ-Bon d P lu s MOP a s a
Br id gin g Dien e Liga n d
Pascal Dotta, P. G. Anil Kumar, 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 May 14, 2004
A new set of Pd-MOP complexes (MOP ) (S)-2-diarylphosphino-1,1′-binaphthyl) has been
prepared. One of these, containing MeO-MOP ()2-(diphenylphosphino)-2′-methoxy-1,1′-
binaphthyl), is shown to act as a chelating ligand with a naphthyl backbone diene bridging
a Pd(I)-Pd(I) bond. This bonding mode exists in both the solid and solution states. A series
of chloro-Pd(II)MOP complexes containing the well-known cyclometalated N,N-dimethyl
benzylamine chelate have been treated with NaBArF to extract the chloride ligand. The
products, starting from the H-MOP, MeO-MOP, and NC-MOP analogues, are all different.
Of particular interest is the product from the H-MOP reaction in that the fourth coordination
position is occupied by a weak Pd-C σ-bond from the naphthyl backbone, on the basis of
13C NMR data. The rate of product formation in the Pd-catalyzed hydrosilylation of styrene
with SiHCl3 has been measured as a function of time for the four auxiliaries H-MOP, MeO-
MOP, HO-MOP, and NC-MOP. The NC-MOP is shown to be much faster than the others,
and a tentative explanation is offered.
In tr od u ction
Frequently, chiral catalysts employ tertiary phos-
phine derivatives as auxiliaries. Indeed, bidentate chiral
phosphines have become so popular that these are
increasingly commercially available, e.g., Duphos and
Binap. However, the recent literature shows that much
Enantioselective homogeneous catalysis employing
late transition metal complexes represents a research
area of growing interest1-5 Relatively small quantities
of complexed chiral auxiliaries, be they oxazolines4 or
phosphines,1,3,5 can be used to prepare substantial
amounts of optically pure organic compounds. Although
much interest has centered on Ru(II)- or Rh(I)-catalyzed
enantioselective hydrogenation, palladium-catalyzed
carbon-carbon (and carbon-nitrogen4 and carbon-
oxygen, etc.) bond making reactions are increasingly
popular.2-7
(1) Burk, M. J .; Cross, M. F.; Martinez, J . P. J . Am. Chem. Soc. 1995,
117, 9375. Burk, M. J . Acc. Chem. Res. 2000, 33, 363-372.
(2) Helmchen, G.; Pfaltz, A. Acc. Chem. Res. 2000, 33, 336-345.
(3) Lautens, M.; Fagnou, K.; Hiebert, S. Acc. Chem. Res. 2003, 36,
48-58.
effort is being invested in the applications of monoden-
tate chiral auxiliaries, e.g., MOP, 1.8-14 The ligands 1
(4) Zim, D.; Buchwald, S. L. Org. Lett. 2003, 5, 2413-2415.
Anderson, K. W.; Mendez-Perez, M.; Priego, J .; Buchwald, S. L. J . Org.
Chem. 2003, 68, 9563-9573. Huang, X. H.; Anderson, K. W.; Zim, D.;
J iang, L.; Klapars, A.; Buchwald, S. L. J Am. Chem Soc. 2003, 125,
10767-10767. Muci, A. R.; Buchwald, S. L. Cross-Coupling Reactions
2002, 219, 131-209. Alcazar-Roman, L. M.; Culkin, D. A.; Hartwig, J .
F. Acc. Chem. Res. 2003, 36, 234-245. Hartwig, J . F.; Rheingold, A.
L.; Liable-Sands, L. M.; Guzei, I. A. J Am. Chem Soc. 2000, 122, 4618-
4630. Hamann, B. C.; Hartwig, J . F. J . Am. Chem. Soc. 1998, 120,
3694-3703. Diederich, F.; Stang, P. J . Metal-Catalyzed Cross-Coupling
Reactions; Wiley-VCH: Weinheim, 1998.
are good auxiliaries for the Pd-catalyzed regioselective
and enantioselective hydrosilylation reaction,8 eq 1, with
the branched product being favored.
(5) Tye, H. J . Chem. Soc., Perkin Trans. 1 2000, 275-298. Ghosh,
A. K.; Mathivanan, P.; Cappiello, J . Tetrahedron Asymmetry 1998, 9,
1-45.
(6) Trost, B. M.; van Vranken, D. L. Chem. Rev. 1996, 96, 395. Trost,
B. M.; Rasdinov, R.; Grenzer, E. M. J . Am. Chem. Soc. 1997, 119,
7879-7880.
(7) van Leeuwen, P.; Kamer, P. C. J .; Reek, J . N. H.; Dierkes, P.
Chem. Rev. 2000, 100, 2741-2769.
10.1021/om0496535 CCC: $27.50 © 2004 American Chemical Society
Publication on Web 08/04/2004

4248 Organometallics, Vol. 23, No. 18, 2004
Dotta et al.
Sch em e 1. MOP Com p lexes Sh ow in g Novel
Although the structural coordination chemistry as-
sociated with chiral bidentate phosphine auxiliaries has
been well studied, there is relatively little literature on
the structural transition metal chemistry associated
with 1. Further, that which is known with respect to
the interactions of 1 with Pd(II) affords a rather mixed
picture. Scheme 1 shows a few of the complexes, 2-6
and 8 (from 7), that have been characterized and reveals
that a number of binding modes are possible.
In ter a ction s
The MOP ligand can function as a σ-donor in com-
plexes 3, 4, and 6 (i.e., as a P,C bidentate), but as a
phosphine, π-olefin chelate in compounds 2, 5, and 8.
Further, more than one naphthyl double bond can be
involved. 13C NMR studies have confirmed the diene
nature of 2.13 Although 2 has not been crystallized, both
NMR and X-ray crystallography support the proposed
structures of 3,14 4,14 5,12c 6,9a,12c and 8.15 Complex 3
arises when ligand 1c adopts an ene-one anionic struc-
ture. Complex 4, with its rather long σ-bond, ca. 2.19
Å,14 has the positive charge in the cation localized in
the organic backbone. It would seem that it is not easy
to predict how the MOP-type ligands will bind to Pd(II)
since both σ- and π-bonds can be formed using different
parts of the aryl backbones (e.g., to carbons 1 and 6 in
8, but to the immediately adjacent double bond in 5).
In any case, 1 and related MOP-type ligands seem to
be capable of acting as multidentate ligands.16 We report
here new Pd-MOP complexes in which there are further
subtle variations on the bonding from the naphthyl
backbone.
Resu lts a n d Discu ssion
Din u clea r P d (I) Com p ou n d 9. During the prepara-
tion of the acetylacetonate compound 4, a modest
(8) (a) Uozumi, Y.; Kitayama, K.; Hayashi, T. Tetrahedron Asym-
metry 1993, 4, 2419-2422. (b) Hayashi, T.; Iwamura, H.; Naito, M.;
Matsumoto, Y.; Uozumi, Y.; Miki, M.; Yanagi, K. J . Am. Chem. Soc.
1994, 116, 775-776. (c) Uozumi, Y.; Kitayama, K.; Hayashi, T.;
Kazunori, K.; Yanagi, K.; Fukuyo, E. Bull. Chem. Soc. J pn. 1995, 68,
713-722. (d) Hayashi, T. Acta Chem. Scand. 1996, 50, 259-266. (e)
Uozumi, Y.; Danjo, H.; Hayashi, T. Tetrahedron Lett. 1998, 39, 8303-
8306. (f) Uozumi, Y. Yakugaku Zasshi-J . Pharm. Soc. J pn. 1998, 118,
193-205. (g) Hayashi, T.; Kawatsura, M.; Uozumi, Y. J . Am. Chem.
Soc. 1998, 120, 1681-1687. (h) Hayashi, T. Acc. Chem. Res. 2000, 33,
354-362. (i) Hayashi, T.; Hirate, S.; Kitayama, K.; Tsuji, H.; Torii, A.;
Uozumi, Y. Chem. Lett. 2000, 1272-1273. (j) Hayashi, T.; Hirate, S.;
Kitayama, K.; Tsuji, H.; Torii, A.; Uozumi, Y. J . Org. Chem. 2001, 66,
1441-1449. (k) Hayashi, T.; Han, J . S.; Takeda, A.; Tang, J .; Nohmi,
K.; Mukaide, K.; Tsuji, H.; Uozumi, Y. Adv. Synth. Catal. 2001, 343,
279-283. (l) Shimada, T.; Mukaide, K.; Shinohara, A.; Han, J . W.;
Hayashi, T. J Am. Chem Soc. 2002, 124, 1584-1585.
quantity of a new dinuclear Pd(I) species was obtained
as a side-product and its structure determined via X-ray
diffraction. Once the structure was known, the new
dinuclear complex, 9, could be prepared in good yield
by direct reaction of the known Pd(I) dimer [Pd2(CH3-
CN)6](BF4)2 with 2 equiv of MeO-MOP, as shown in the
eq 2:
(9) (a) Wang, X. P.; Li, X.; Sun, J .; Ding, K. Organometallics 2003,
22, 1856-1862. (b) Xu, L.; Shi, Q.; Li, X.; J ia, X.; Huang, X.; Wang,
R.; Zhou, Z.; Lin, Z.; Chan, A. S. C. Chem. Commun. 2003, 1666-1667.
(10) Soleilhavoup, M.; Viau, L.; Commenges, G.; Lepetit, C.; Chau-
vin, R. Eur. J . Inorg. Chem. 2003, 207-212.
(11) Maillard, D.; Bayardon, J .; Kurichiparambil, J . D.; Nguefack-
Fournier, C.; Sinou, D. Tetrahedron: Asymmetry 2002, 13, 1449-1456.
(12) (a) Gouriou, L.; Lloyd-J ones, G. C.; Vyskocil, T.; Kocovsky, P.
J . Organomet. Chem. 2003, 687, 525-537. (b) Lloyd-J ones, G. C.;
Stephen, S. C.; Murray, M.; Butts, C. P.; Vyskocil, S.; Kocovsky, P.
Chem. Eur. J . 2000, 6, 4348-4357. (c) Kocovsky, P.; Vyskocil, S.;
Cisarova, I.; Sejbal, J .; Tislerova, I.; Smrcina, M.; Lloyd-J ones, G. C.;
Stephen, S. C.; Butts, C. P.; Murray, M.; Langer, V. J . Am. Chem. Soc.
1999, 121, 7714-7715.
(13) Dotta, P.; Kumar, P. G. A.; Pregosin, P. S.; Albinati, A. Helv.
Chim. Acta 2004, 87, 272-278.
In this complex, the naphthyl backbone of 1b acts as
a bridging diene ligand. The 13C data for 9 (see Figure
1 and Table 1 for data and numbering) show that the
two fully substituted carbons, 1 (99.7 ppm) and 6 (136.7
ppm), and the two dCH carbons 4 (85.0 ppm) and 5
(79.4 ppm) show typical strongly low-frequency-shifted
signals, due to the π-complexation.
(14) Dotta, P.; Kumar, P. G. A.; Pregosin, P. S.; Albinati, A.; Rizzato,
S. Organometallics 2003, 22, 5345-5349.
(15) Faller, J . W.; Sarantopoulos, N. Oranometallics 2004, 23, 2008-
2014.
(16) There are now a few examples involving Pd(0), see: Marshall,
W. J .; Grushin, V. V. Organomertallics 2003, 22, 555-562. Yin, J . J .;
Rainka, M. P.; Zhang, X. X.; Buchwald, S. L. J Am. Chem Soc. 2002,
124, 1162-1163. Reid, S. M.; Boyle, R. C.; Mague, J . T.; Fink, M. J . J .
Am. Chem. Soc. 2003, 125, 7816-7817.

Palladium MOP Compounds
Organometallics, Vol. 23, No. 18, 2004 4249
reported the solid-state structures for PdCl(η3-CH2C-
(Me)CH2)(MeO-MOP)8b and trans-PdCl2(MeO-MOP)2,8c
and the Pd-P distances in these molecules, ca. 2.31 Å
and ca. 2.34 Å, respectively, are in good agreement with
the two Pd-P separations found in 9: Pd(2)-P(2) )
2.305(1) Å and Pd(1)-P(1) ) 2.313(1) Å. There are eight
Pd-(olefin carbon) distances: four from the fully sub-
stituted carbons, Pd(1)-C(1A) ) 2.171(4) Å, Pd(1)-
C(10A) ) 2.388(3) Å, Pd(2)-C(1B) ) 2.182(4) Å, and
Pd(2)-C(10B) ) 2.495(4) Å, plus four from the dCH
carbons, Pd(2)-C(8A) ) 2.212(4) Å, Pd(2)-C(9A) )
2.260(5) Å, Pd(1)-C(8B) ) 2.181(4) Å, and Pd(1)-C(9B)
) 2.336(4) Å. On the basis of these bond distances, it
appears that the Pd-olefin bonding is very asymmetric.
Clearly several of these separations are relatively long,
since the literature values for Pd-C(η2-olefin) complexes
are on the order of 2.18 Å.17
F igu r e 1. Section of the 13C HMQC spectrum for 9,
showing the cross-peaks for the two coordinated dCH
resonances, at relatively low frequency.
Further, several of the C-C distances are also rather
long, e.g., C(1A)-C(2A) at 1.491(7) Å and C(1B)-C(2B)
at 1.493(6) Å, suggesting localized single bonds between
these atoms.
Ta ble 1. 13C Ch em ica l Sh ifts a n d ∆δ Va lu esa for 9
a n d MeO-MOP
There are several structural reports of di (or poly)
olefins bridging Pd(I) dimers,18,19 so that there is
precedence for the basic structure for 9; nevertheless it
is noteworthy that the MOP ligand complexes in this
fashion.
Cyclom eta la ted Com p lexes w ith MOP . Although
it is now abundantly clear that the naphthyl backbone
in atropisomeric phosphines can be involved in π-bond-
ing to the Pd(II) (and also to Ru(II)20,21), the range of
bonding types is not yet well defined. To further explore
this area, the cyclopalladated MOP complexes 10 and
11 were prepared via the usual bridge-splitting reaction
as shown in Scheme 2. The decision for a cyclometalated
Pd complex was based on the fact that many catalytic
cycles involving palladium (e.g., hydrosilylation or cross-
coupling) contain a reactive species with a metal-
carbon σ-bond. The ligands 1a ′ and 1b′ (both with Ar )
3,5-di-t-Bu-phenyl substituents) were used previously22
in a catalytic study and serve only as additional
examples. Extraction of the chloride with NaBArF in
carbon
MeO-MOP
9
∆δ
1
2
3
4
5
6
122.0
134.4
129.1
130.2
113.0
155.5
55.7
99.7
131.6
123.4
85.0
79.4
136.7
57.6
-22.3
-2.8
-5.7
-45.2
-33.6
-18.8
+1.9
OMe
a
500 MHz, CD2Cl2.
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 9a
Pd(1)-Pd(2)
Pd(1)-P(1)
2.7265(4)
2.313(1)
2.388(3)
2.181(4)
2.336(4)
2.171(4)
1.491(7)
1.493(6)
1.423(6)
1.416(6)
1.423(7)
1.390(7)
1.423(6)
Pd(2)-P(2)
2.305(1)
2.626(4)
2.495(4)
2.212(4)
2.260(5)
2.182(4)
1.493(6)
1.512(7)
1.409(8)
1.412(6)
1.427(7)
1.405(6)
1.414(6)
Pd(2)-C(2B)
Pd(2)-C(10B)
Pd(2)-C(8A)
Pd(2)-C(9A)
Pd(2)-C(1B)
C(1B)-C(2B)
C(1B)-C(11B)
C(1B)-C(10B)
C(2B)-C(7B)
C(7B)-C(8B)
C(8B)-C(9B)
C(9B)-C(10B)
Pd(1)-C(10A)
Pd(1)-C(8B)
Pd(1)-C(9B)
Pd(1)-C(1A)
C(1A)-C(2A)
C(1A)-C(11A)
C(1A)-C(10A)
C(2A)-C(7A)
C(7A)-C(8A)
C(8A)-C(9A)
C(9A)-C(10A)
P(1)-Pd(1)-Pd(2) 173.31(3) P(2)-Pd(2)-Pd(1) 175.35(3)
a
The numbering scheme used in this table differs from that
used for the NMR due to the need to distinguish the two halves
(rings a and b) of the MeO-MOP ligand.
dichloromethane afforded the new derivatives 12 and
13, in which the methoxy oxygen atoms of 1b and 1b′
Suitable crystals of 9 were obtained from dichloro-
methane/pentane, and a view of the structure for this
dication is shown in Figure 2. A list of selected bond
distances and bond angles is given in Table 2. The
structure of the complex clearly shows the Pd-Pd bond,
with a separation, Pd(1)-Pd(2) ) 2.727 Å. This distance
is well within the expected range17 for this type of
metal-metal bond. Hayashi and co-workers have
(18) Leoni, P.; Pasquali, M.; Sommovigo, M.; Albinati, A.; Lianza,
F.; Pregosin, P. S.; Ruegger, H. Organometallics 1993, 12, 4503-4508.
Leoni, P.; Pasquali, M.; Sommovigo, M.; Albinati, A.; Pregosin, P. S.;
Ruegger, H. Organometallics 1996, 15, 2047-2052.
(19) Murahashi, T.; Uemura, T.; Kurosawa, H. J . Am. Chem Soc.
2003, 125, 8436-8437. Murahashi, T.; Okuno, T.; Nagai, T.; Kurosawa,
H. Organometallics 2002, 21, 3679-3682. Murahashi, T.; Otani, T.;
Okuno, T.; Kurosawa, H. Angew. Chem., Int. Ed. 2000, 39, 537.
Murahashi, T.; Mochizuki, E.; Kai, Y.; Kurosawa, H. J . Am. Chem.
Soc. 1999, 121, 10660-10661.
(20) den Reijer, C. J .; Dotta, P.; Pregosin, P. S.; Albinati, A. Can. J .
Chem. 2001, 79, 693-704. Geldbach, T. J .; Pregosin, P. S. Eur. J . Inorg.
Chem. 2002, 1907-1918. Geldbach, T. J .; Pregosin, P. S.; Albinati, A.
Organometallics 2003, 22, 1443-1451, and references therein.
(17) Orpen, A. G.; Brammer, L.; Allen, F. H.; Kennard, O.; Watson,
D. G.; Taylor, R. J . Chem. Soc., Dalton 1989, S1-S83.

4250 Organometallics, Vol. 23, No. 18, 2004
Dotta et al.
Sch em e 2. Cyclop a lla d a ted Com p lexes w ith
MeO-MOP a n d H-MOP
F igu r e 2. ORTEP view of the structure of complex
dication 9. Ellipsoids are drawn at 50% probability. The
numbering scheme used in this figure differs from that
used for the NMR, due to the need to distinguish the two
halves (rings a and b) of the MeO-MOP ligand.
are now complexed to the Pd(II). The geometry shown,
which places the MeO and Me2N groups close to one
another, is supported by NOESY results (see Figure 3).
13C NMR results for these new compounds are given
in Table 3. We note that, for 12 and 13, there is a 9.5-
10.5 ppm high-frequency shift of the methoxy carbon,
relative to 10 and 11, respectively, due to the oxygen
coordination. The cyclopalladated carbon resonance, L1,
is shifted ca. 10-11 ppm to low frequency, in agreement
with the expectation of a weaker ligand than chloride
in trans position.23 The aromatic carbons C1-C6 change
minimally relative to the chloride analogue. These NMR
data for complexes 10-13 are useful primarily as
models for the 13C NMR studies, which will follow.
Scheme 2 also shows structures for the cyclopalla-
dated H-MOP complexes, 16 and 17, derived from the
same reactions (bridge splitting to afford 14 and 15 and
then chloride extraction). Table 4 shows the pertinent
13C data. The backbone carbon C-1 has now shifted to
F igu r e 3. Section of the 2-D NOESY NMR spectrum for
12, showing the cross-peaks due to the NOEs from the
proximate MeO (and NCH2) groups to the nonequivalent
Me2N groups (on the y-axis). One of the N-methyl groups
is coupled to the MOP 31P atom.
higher frequency (15.8 and 14.1 ppm for 16 and 17,
respectively), while C-6 (which is closer to the Pd atom)
has shifted markedly to lower frequency (-24.4 and
-26.3 ppm for 16 and 17, respectively). We consider
these NMR data to be consistent with some weak
σ-bonding character between C-6 and the Pd atom, in
analogy with what we have observed in 4. The much
smaller coordination chemical shift for C-6 in 16 and
17 (ca. -25 ppm) relative to 4 (ca. -50 ppm) arises due
to the presence of a good σ-donor (the cyclopalladated
carbon) rather than the acetyl acetonate oxygen donor
in 4, i.e., differences in trans influence effects. We
suggest some positive charge at C-1 and thus the high
frequency shift, although some of the charge is surely
delocalized over the naphthyl fragment. We cannot
exclude the possibility of an η1-π bond, i.e., an interac-
tion from the π-orbital of a single naphthyl carbon, as
(21) Cyr, C. W.; Rettig, S. J .; Patrick, B. O.; J ames, B. R. Organo-
metallics 2002, 21, 4672-4679. Doherty, S.; Newman, C. R.; Hardacre,
C.; Nieuwenhuyzen, M.; Knight, J . G. Oranometallics 2003, 22, 1452-
1462.
(22) Dotta, P.; Kumar, P. G. A.; Pregosin, P. S.; Albinati, A.; Rizzato,
S. Organometallics 2004, 23, 2295-2304.
(23) Tschoerner, M.; Kunz, R. W.; Pregosin, P. S. Magn. Reson.
Chem. 1999, 37, 91-97. Tschoerner, M.; Pregosin, P. S. Inorg. Chim.
Acta 1999, 290, 95-99.

Palladium MOP Compounds
Organometallics, Vol. 23, No. 18, 2004 4251
Ta ble 3. 13C Ch em ica l Sh iftsa for 10-13
Sch em e 3. Cyclop a lla d a ted Com p lexes w ith
NC-MOP
Ar ) Ph
10
12
∆δ
1
2
3
4
5
6
119.9
134.6
129.1
130.6
112.2
154.7
125.2
132.7
132.2
132.8
119.5
155.5
+5.3
-1.9
+3.1
+2.2
+7.3
+0.8
+10.5
-10.9
OCH3
L1
55.3 (3.40b)
151.8
65.8 (3.39b)
140.9
Ar ) 3,5-t-Bu
11
13
∆δ
1
2
3
4
5
6
121.6
134.5
128.9
130.4
113.8
155.6
125.4
133.2
131.9
133.0
119.5
155.2
+3.8
-1.3
+3.0
+2.6
+5.7
-0.4
+9.5
-10.0
OCH3
L1
56.3 (3.33b)
151.6
65.8 (3.39b)
141.6
a
b
500 MHz, CD2Cl2. 1H chemical shift.
Ta ble 4. 13C Ch em ica l Sh iftsa for 14-17
Ta ble 5. 13C Ch em ica l Sh ifts for 18 a n d 19a
Ar ) Ph
14
16
∆δ
Ar ) Ph
18
19
∆δ
1
2
3
4
5
6
L1
133.4
133.0
133.3
129.2
125.0
131.0b
150.1
149.2
132.0
134.5
131.3
127.5
106.6c
149.4
+15.8
1
2
3
4
5
6
L1
142.9
133.0
134.9
129.3
127.1
112.4
151.9
146.2
132.0
136.0
131.6
125.2
107.3
145.0
+3.3
-1.0
+1.1
+2.3
-1.9
-5.1
-6.9
-1.0
+1.2
+2.1
+2.5
-24.4
-0.7
Ar ) 3,5 t-Bu
15
17
∆δ
a
500 MHz, CD2Cl2.
1
2
3
4
5
6
L1
136.2
133.4
133.0
129.3
125.1
131.7
150.4
150.3
132.1
134.6
131.1
127.7
105.4
150.4
+14.1
-1.3
+1.6
+1.8
+2.6
-26.3
0.0
and a mass spectrum consistent with the formulation
[Pd(C6H4CH2NMe2)(1d )](BArF). The IR spectrum shows
a modest 10 cm-1 change in the CN frequency on going
from 18 to 19. We find no water signal in either the IR
1
or H NMR of 19. Addition of Bu4NCl leads to formation
a
b
c
500 MHz, CD2Cl2. 1J CH(C6) ) 163 Hz for 14. 1J CH(C6) )
of 18 (reverse reaction) cleanly. The 13C data for 19 are
given in Table 5 and show that the naphthyl backbone
does not interact with the metal; that is, there is no
evidence for π- or-σ-complexation. Although the exact
structure of 19 is not certain (it still might be a dynamic
aquo complex, or the nitrile might be involved, weakly,
with the Pd(II)), compound 19 does not show the
naphthyl backbone interaction related to that found for
15 or 17. We do not believe that 19 is a three-coordinate
Pd(II) complex.
155 Hz for 16.
this has been proposed recently;24 however, an η1-bond
does not usually result in a strong high-frequency shift
for the adjacent carbon. In any case, whether the new
interaction represents an extremely weak σ-bond or
some form of π-polarization, this represents yet another
new bonding possibility for Pd-MOP.
The 1J (13C,1H) values for the hydrogen at C-6 are 163
and 155 Hz for 14 and 16, respectively, so that we have
no reason to consider an agostic interaction. The chemi-
cal shift of the cyclopalladated carbon resonance, L1, is
more or less unchanged relative to the chloride ana-
logue; that is, the trans influence of this new bond is
similar to that of a chloride.
The solid-state structure of the chloride complex 15
is known.22 An ORTEP view of this neutral species is
shown as Supplementary Figure 1. Given that carbon
C6 is quite close in space to the position occupied by
the chloride ligand, it is not difficult to imagine an
interaction from this carbon, once the chloride is re-
moved via the NaBArF reagent.
In connection with the characterization of the new
BArF cations 12, 16, and 19, we note that the electron
spray ionization mass spectrum (from methanol) shows
a major signal for 19+MeOH, i.e., the solvated NC-MOP
analogue, whereas, the MeO-MOP and H-MOP cations,
12 and 16, gave strong peaks for the molecular ion,
without solvent, presumably because the fourth coordi-
nation position is blocked as described above.
Com m en ts on Hyd r osilyla tion Ca ta lysis. We have
recently noted that NC-MOP, 1d , seems to produce
rather different results than either 1a or 1b in terms
of its enantioselectivity22 in the Pd-catalyzed hydro-
silylation of styrene (see eq 1). Using 0.05 mol % [Pd-
(µ-Cl)(η3-C3H5)]2 as precursor, together with 0.2 mol %
ligand 1d , affords the S enantiomer, whereas use of 1a ,b
yields the R enantiomer.22 Further, we have now
measured the rate of conversion of styrene as a function
of time for the four auxiliaries 1a -1d and show this
plot in Figure 4. Clearly, NC-MOP, 1d , affords a catalyst
Scheme 3 shows an analogous reaction sequence for
1d , the cyano-MOP derivative. The product, 19, gives a
singlet in the 31P NMR spectrum, plus a microanalysis
(24) Geldbach, T. J .; Drago, D.; Pregosin, P. S. J . Organomet. Chem.
2002, 643, 214-222. Reid, S. M.; Boyle, R. C.; Mague, J . T.; Fink, M.
J . J . Am. Chem. Soc. 2003, 125, 7816-7817.

4252 Organometallics, Vol. 23, No. 18, 2004
Dotta et al.
Ta ble 6. Exp er im en ta l Da ta for th e X-r a y
Diffr a ction Stu d y of Com p ou n d 9.
formula
mol wt
C66H50B2F8O2P2Pd2
1323.42
data coll. T, K
293
diffractometer
Bruker SMART CCD
cryst syst
monoclinic
space group (no.)
P21 (4)
a, Å
b, Å
c, Å
â, deg
V, Å3
Z
11.342(1)
16.995(1)
15.126(3)
100.175(2)
2869.7(4)
2
1.532
7.54
F
(calcd), g cm-3
µ, cm-1
radiation
Mo KR (graphite monochrom.,
λ ) 0.71073 Å)
2.18 < θ < 25.62
23 404
10 096
9093
θ range, deg
no. data collected
no. indep data
F igu r e 4. Plot showing the development of product as a
function of time for the four auxiliaries, MeO-MOP, H-
MOP, OH-MOP, and NC-MOP, in the hydrosilylation of
styrene.
no. obsd reflns (no)
2
2
[|Fo| > 2.0σ(|F| )]
no. of params refined (nv)
abs structure (Flack’s) param
729
0.03(2)
0.0417
0.0336
0.0833
1.026
that is about 1 order of magnitude faster than the
others. Although the reaction is quantitative for all four
auxiliaries, there appears to be an incubation period for
the H-MOP and MeO-MOP reactions. Interestingly, the
observed ee does not follow the kinetics, i.e., 92%, 7%,
and 42% for the H, MeO, and CN analogues, respec-
tively.22
a
Rint
R2 (obs reflns)
Rw2 (obs reflns)b
GOFc
R ) ∑(|Fo - (1/k)Fc|)/∑|Fo|. Rw ) [∑w(Fo - (1/k)Fc2)2/
a
b
2
2
∑w|Fo | ]. c GOF ) [∑w(Fo - (1/k)Fc2)2/(no - nv)]1/2
.
2 2
2
This difference in kinetic behavior might involve a
“simple” electronic effect, based on the differences in the
electronic and steric characteristics of the substituents
in these ligands.25 However, given the different ways
in which these MOP ligands choose to “occupy” a vacant
palladium coordination position (i.e., using the MeO
group as oxygen donor from MeO-MOP, or the π-system
from the naphthyl backbone of H-MOP, or neither of
these, as in the NC-MOP), we suggest that the Pd
complexes, which arise from these ligands, may well
adopt very different structures along the hyrosilylation
reaction pathway. This implies that the choice of MOP
ligand, for any given catalytic reaction, is not trivial.
coupling constants (J ) in Hz. Elemental analyses and mass
spectroscopic studies were performed at ETHZ.
The numbering system used for the MOP ligands in the
NMR measurements is the same as that used previously.13,14
While it is useful to know if the R substituents (and/
or the naphthyl backbone) play a role in relevant MOP
organometallic chemistry, it may be that chelation, be
it via the methoxy oxygen or the naphthyl backbone,
only serves to slow one or more of the critical steps (e.g.,
olefin complexation). However, when the sense of the
enantioselectivity is affected, the role of the R substitu-
ent becomes important.
Cr ysta llogr a p h y. Orange crystals of 9, suitable for X-ray
diffraction, were obtained from a dichloromethane/pentane
solution and are air stable. A prismatic crystal was mounted
on a Bruker SMART diffractometer, equipped with a CCD
detector, for the unit cell determination and the data collection.
The space group was unambiguously determined from the
systematic absences, while the cell constants were refined by
least-squares, at the end of the data collection, by using 993
reflections (θmax e 25.3°). The data were collected by using ω
scans, in steps of 0.3 deg. For each of the 1860 collected frames,
counting time was 30 s. Selected crystallographic and other
relevant data are listed in Table 6 and in the Supporting
Information (Table S1).
Exp er im en ta l Section
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,8 the N,N′-dimethylbenzylamine
cyclopalladated starting material,26 and the dinuclear com-
Data were corrected for Lorentz and polarization factors
with the data reduction software SAINT27 and empirically for
absorption using the SADABS program.28 The structures were
solved by direct and Fourier methods and refined by full matrix
27
pound [Pd2(CH3CN)6](BF4)2 were prepared by literature
methods. 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;
least-squares29 (the function minimized being ∑[w(F2
-
o
(1/k)F2 )2]). Anisotropic displacement parameters were used for
c
all atoms. The contribution of the hydrogen atoms, in their
(25) The significant difference in rate between the OH and MeO
analogues makes a Hammett-type correlation unlikely.
(26) Cope, A. C.; Friedrih, A. C. J . Am. Chem. Soc. 1968, 90, 909.
(27) BrukerAXS, SAINT, Integration Software; Bruker Analytical
X-ray Systems: Madison, WI, 1995.
(28) Sheldrick, G. M. SADABS, Program for Absorption Correction;
University of Go¨ttingen: Go¨ttingen, Germany, 1996.
(29) Sheldrick, G. M. SHELX-97. Structure Solution and Refinement
Package; Universita¨t Go¨ttingen, 1997.

Palladium MOP Compounds
Organometallics, Vol. 23, No. 18, 2004 4253
calculated positions (C-H ) 0.95 Å, B(H) ) 1.3/1.5B(Cbonded
)
3.51 (b, 1 H, H-L7), 3.33 (s, OCH3), 2.65 (s, CH3-L8), 2.53 (s,
CH3-L9), 1.08 (s, 18 H, C(CH3)3), 0.91 (s, 18 H, C(CH3)3). 13C
NMR (CD2Cl2, 125 MHz): δ 155.6 (C-6), 151.6 (C-L1), 148.3
(C-L6), 138.8 (C-L2), 134.5 (C-2), 130.4 (C-4), 128.9 (C-3), 127.7
(C-10), 124.4 (C-L3), 123.3 (C-L4), 121.8 (C-L5), 121.6 (C-1),
113.8 (C-5), 73.2 (C-L7), 56.3 (OCH3), 50.6 (C-L8), 50.2 (C-L9),
35.1 (C(CH3)3), 34.7 (C(CH3)3), 31.3 (C(CH3)3), 31.2 (C(CH3)3).
31P NMR (CD2Cl2, 202 MHz): δ 49.6 (bs). MS (MALDI): 932.4
(M+ - Cl, 100%).
For all of the chloride abstraction reactions that follow,
below, NMR monitoring shows the reaction to be essentially
quantitative. The weight losses arise from handling the
relatively small amounts of noncrystalline material.
(Å2)), was included in the refinement using a riding model.
Upon convergence (see Table S1), the final Fourier difference
map showed no significant peaks. No extinction correction was
deemed necessary. The scattering factors used, corrected for
the real and imaginary parts of the anomalous dispersion, were
taken from the literature.30 The standard deviations on
intensities were calculated in terms of statistics alone. Refining
the Flack’s parameter tested the handedness of the structure
(cf. Table 6).31 All calculations were carried out by using the
PC versions of the SHELX-9729and ORTEP programs.32
Syn th eses. The syntheses of the complexes 10, 12, and 16
gave products that contained very small (ca. 1%) quantities
of phosphine oxide.
Syn th esis of [P d (C6H4CH2NMe2)(1b)](BAr F ), 12. A 60
mg amount of 10 (0.081 mmol) and 71.4 mg of NaBArF (0.081
mmol) were stirred for 30 min at room temperature in 3 mL
of CH2Cl2. Filtration over Celite and washing with 0.5-1.0 mL
of dichloromethane was followed by removal of the solvent to
Syn th esis of [P d (1b)]2(BF 4), 9. To a mixture of 20 mg of
33
[Pd2(CH3CN)6](BF4)2 (0.032 mmol) and 29.6 mg of 1b (0.063
mmol) was added 1.5 mL of CH3CN and the red solution
stirred for 20 min. After removal of the solvent, the residue
was precipitated from a CH2Cl2/ether solution and washed
twice with ether. Recrystallization from CH2Cl2/ether gave 20
mg (47%) of 9 as a red crystalline material. Anal. Calcd for
give 92 mg (72%) of the product. Anal. Calcd for C74H49NOBF24
-
PPd: C, 56.53; H, 3.14; N, 0.89. Found: C, 57.40; H, 3.29; N,
0.94. 1H NMR (CD2Cl2, 500 MHz): δ 7.88 (d, 3J HH ) 9.0, H-4),
3
3
7.61 (d, J HH ) 8.3, H-10), 7.44 (H-4), 7.27 (H-9), 6.98 (t, J HH
C
66H50O2B2F8P2Pd2‚C2H4Cl2: C, 57.37; H, 3.83. Found: C,
3
57.32; H, 4.86. 1H NMR (CD2Cl2, 500 MHz): δ 8.15 (d, 3J HH
)
) 7.7, H-8), 6.86 (d, J HH ) 7.3, H-L5), 6.72 (H-L4), 6.48 (bd,
3J HH ) 8.1, H-7), 6.16 (t, J HH ) 7.9, H-L3), 5.94 (t, J HH
)
3
3
8.7, H-14), 8.01 (m, Phenyl-H, 2 H), 7.82-7.89 (m, Phenyl-H,
3 H), 7.70 (m, H-15), 7.76 (m, H-4), 7.60-7.67 (m, Phenyl-H, 5
4J PH ) 7.1, H-L2), 4.56 (d, J HH ) 14.1, H-L7), 3.48 (dd, J HH
2
2
4
4
3
4
3
) 13.7, J PH ) 3.6, H-L7), 3.39 (s, OCH3), 2.91 (d, J PH ) 3.2,
H), 7.53 (dt, J HH ) 7.6, J HH ) 0.8, H-19), 7.24 (dt, J HH
)
CH3-L8), 2.86 (d, J PH ) 1.1, CH3-L9). 13C NMR (CD2Cl2, 125
4
4
3
4
7.9, J HH ) 1.0, H-18), 6.83 (dt, J HH ) 7.9, J HH ) 1.1, H-8),
3
3
MHz): δ 155.5 (C-6), 146.8 (C-L6), 140.9 (C-L1), 138.3 (C-L2),
132.8 (C-4), 132.7 (C-2), 132.2 (C-3), 128.4 (C-10), 127.5 (C-8),
127.0 (C-7), 126.7 (C-9), 126.5 (C-L3), 125.8 (C-L4), 125.2 (C-
1), 124.0 (C-L5), 70.6 (C-L7), 65.8 (OCH3), 51.6 (C-L8), 50.3
(C-L9). 31P NMR (CD2Cl2, 202 MHz): δ 39.6 (s). MS (ESI):
707.50 (M+ - BArF, 90%).
Syn th esis of [P d (C6H4CH2NMe2)(1b′)](BAr F ), 13. A 50
mg amount of 11 (0.052 mmol) and 45.7 mg of NaBArF (0.052
mmol) were stirred for 30 min at room temperature in 3 mL
of CH2Cl2. Filtration over Celite and washing with 0.5-1.0 mL
of dichloromethane was followed by removal of the solvent to
6.72 (t, J HH ) 7.9, H-9), 6.69 (d, J HH ) 8.4, H-7), 6.48 (d,
3J HH ) 8.7, H-17), 6.39 (d, J HH ) 8.1, H-10), 5.69 (d, J HH
)
3
3
7.2, H-5), 3.16 (s, OCH3, 3 H). 13C NMR (CD2Cl2, 125 MHz):
δ 142.3 (C-11), 139.4 (C-16), 136.7 (C-6), 136.6 (C-13), 133.2
(C-14), 132.5 (C-8), 131.8 (C-12), 131.6 (C-2), 129.9 (C-18),
129.9 (C-9), 129.0 (C-20), 127.9 (C-15), 127.2 (C-10), 126.0
(C-7), 125.2 (C-17), 123.4 (C-3), 99.7 (C-1), 85.0 (C-4), 79.4
(C-5), 57.6 (OCH3). 31P NMR (CD2Cl2, 202 MHz): δ 38.4 (s).
Syn th esis of P d Cl(C6H4CH2NMe2)(1b), 10. To a mixture
of 88.3 mg of [Pd(µ-Cl)(C6H4CH2NMe2)]2 (0.16 mmol) and 150
mg of 1b (0.32 mmol) was added 4 mL of CH2Cl2. The solution
was stirred for 30 min at room temperature. After removal of
the solvent, the crude product was recrystallized from toluene/
pentane to give 143 mg (60%) of the product. Anal. Calcd for
give 61 mg (65%) of the product. Anal. Calcd for C90H81NOBF24
-
PPd: C, 60.16; H, 4.54; N, 0.78. Found: C, 60.22; H, 4.74; N,
0.79. 1H NMR (CD2Cl2, 500 MHz): δ 7.89 (d, 3J HH ) 9.0, H-4),
3
3
7.62 (d, J HH ) 8.3, H-10), 7.46 (H-5), 7.25 (H-9), 6.81 (d, J HH
C
42H37NOPClPd: C, 67.75; H, 5.01; N, 1.88. Found: C, 68.33;
3
3
1
3
) 7.1, H-L5), 6.67 (t, J HH ) 7.3, H-L4), 6.52 (d, J HH ) 8.3,
H-7), 6.04 (t, J HH ) 7.7, H-L3), 5.76 (t, J HH
H, 5.69; N, 1.78. H NMR (CD2Cl2, 500 MHz): δ 7.64 (d, J HH
) ca. 9.2, H-4), 7.64 (d, J HH ) ca. 9.2, H-10), 7.24 (d, J HH
8.6, H-7), 7.19 (H-9), 7.08 (H-8), 6.82 (d, J HH ) 7.3, H-L5),
6.78 (H-5), 6.65 (t, 3J HH ) 7.5, H-L4), 6.15 (t, 3J HH ) 7.7, H-L3),
6.08 (t, 3J HH ) 6.8, H-L2), 3.78 (d, 4J PH ) 1.3, 2 H, H-L7), 3.40
)
4J PH ) 7.1,
2
3
3
3
3
)
2
3
H-L2), 4.54 (d, J HH ) 13.3, 1 H, H-L7), 3.49 (dd, J HH ) 13.5,
4J PH ) 3.4, 1 H, H-L7), 3.39 (s, OCH3), 2.94 (s, CH3-L8), 2.85
(s, CH3-L9), 1.08 (s, 18 H, C(CH3)3), 1.00 (s, 18 H, C(CH3)3).
13C NMR (CD2Cl2,125 MHz): δ 155.2 (C-6), 146.0 (C-L6), 141.6
(C-L1), 138.4 (C-L2), 133.2 (C-2), 133.0 (C-4), 131.9 (C-3), 128.5
(C-10), 126.4 (C-9), 126.4 (C-7), 126.3 (C-L3), 125.7 (C-L4),
125.4 (C-1), 123.6 (C-L5), 119.5 (C-5), 70.6 (C-L7), 65.8 (OCH3),
51.6 (C-L8), 50.0 (C-L9), 35.1 (C(CH3)3), 34.8 (C(CH3)3), 31.2
(C(CH3)3), 31.1 (C(CH3)3). 31P NMR (CD2Cl2, 202 MHz): δ 43.8
(s). MS (ESI): 932.19 (M+ - BArF, 100%).
4
4
(s, OCH3), 2.68 (d, J PH ) 2.5, CH3-L8), 2.67 (d, J PH ) 2.5,
CH3-L9). 13C NMR (CD2Cl2, 125 MHz): δ 154.7 (C-6), 151.8
(C-L1), 148.8 (C-L6), 138.5 (C-L2), 134.6 (C-2), 130.6 (C-4),
129.1 (C-3), 127.6 (C-10), 127.2 (C-7), 124.5 (C-L3), 123.6 (C-
L4), 122.2 (C-L5), 119.9 (C-1), 112.2 (C-5), 73.4 (C-L7), 55.3
(OCH3), 50.8 (C-L8), 50.6 (C-L9). 31P NMR (CD2Cl2, 202
MHz): δ 48.1 (s). MS (MALDI): 708.1 (M+ - Cl, 100%).
Syn th esis of P d Cl(C6H4CH2NMe2)(1b′), 11. To a mixture
of 59.7 mg of [Pd(µ-Cl)(C6H4CH2NMe2)]2 (0.108 mmol) and 150
mg of 1b′ (0.216 mmol) was added 4 mL of CH2Cl2. The
solution was stirred for 30 min at room temperature. The
solvent was distilled off to give a quantitative yield of the
product. Anal. Calcd for C58H69NOPClPd: C, 71.89; H, 7.18;
Syn th esis of [P d (C6H4CH2NMe2)(1a )](BAr F ), 16. A 50
mg amount of 14 (0.070 mmol) and 62 mg of NaBArF (0.070
mmol) were stirred for 30 min at room temperature in 2 mL
of CH2Cl2. Filtration over Celite and washing with 0.5-1.0 mL
of dichloromethane was followed by removal of the solvent to
give 58 mg (54%) of the product. Anal. Calcd for C73H47NBF24
-
1
PPd: C, 56.85; H, 3.07; N, 0.91. Found: C, 57.76; H, 3.21; N,
N, 1.45. Found: C, 71.93; H, 7.23; N, 1.39. H NMR (CD2Cl2,
0.99. 1H NMR (CD2Cl2, 500 MHz): δ 8.20 (d, 3J HH ) 8.6, H-4),
3
3
500 MHz): δ 7.63 (d, J HH ) 8.3, H-4), 7.63 (d, J HH ) 8.3,
3
3
3
7.84 (d, J HH ) 8.3, H-10), 7.81 (dd, J HH ) 8.8 and 6.2, H-5),
7.34 (H-9), 7.25 (H-6), 6.80 (H-L5), 6.67 (H-L4), 6.66 (H-8), 6.21
H-10), 6.89 (b, H-5), 6.69 (H-L5), 6.54 (t, J HH ) 7.5, H-L4),
6.00 (t, J HH ) 7.5, H-L3), 5.80 (b, H-L2), 3.65 (b, 1 H, H-L7),
3
3
3
4
(t, J HH ) 7.7, H-L3), 6.15 (t, J HH ) J PH ) 7.7, H-L2), 6.11
(d, 3J HH ) 8.3, H-7), 4.56 (d, 2J HH ) 13.3, H-L7), 3.45 (dd, 2J HH
(30) International Tables for X-ray Crystallography; Wilson, A. J .
C., Ed.; Kluwer Academic Publisher: Dordrecht, The Netherlands,
1992; Vol. C.
(31) Flack, H. D. Acta Crystallogr. 1983, A 39, 876.
(32) Farrugia, L.J . J . Appl. Crystallogr. 1997, 30, 565.
(33) Murahashi, T.; Nagai, T.; Okuno, T.; Matsutani, T.; Kurosawa,
H. Chem. Commun. 2000, 1689-1690.
4
4
) 13.3, J PH ) 2.1, H-L7), 3.12 (bd, J PH ) 2.8, CH3-L8), 2.58
(s, CH3-L9). 13C NMR (CD2Cl2,125 MHz): δ 149.4 (C-L1), 149.2
(C-1), 145.1 (C-L6), 137.6 (C-L2), 134.5 (C-3), 132.0 (C-2), 131.3
(C-4), 129.5 (C-9), 128.3 (C-10), 128.0 (C-8), 127.5 (C-7), 127.5
(C-5), 127.4 (C-L3), 126.0 (C-L4), 124.4 (C-L5), 106.6 (C-6), 72.8

4254 Organometallics, Vol. 23, No. 18, 2004
Dotta et al.
(C-L7), 51.5 (C-L8), 49.0 (C-L9). 31P NMR (CD2Cl2, 202 MHz):
δ 36.3 (s). MS (ESI): 677.80 (M+ - BArF, 90%).
Syn th esis of [P d (C6H4CH2NMe2)(1a ′)](BAr F ), 17. A 60
mg amount of 15 (0.064 mmol) and 56.2 mg of NaBArF (0.064
mmol) were stirred for 30 min at room temperature in 3 mL
of CH2Cl2. Filtration over Celite and washing with 0.5-1.0 mL
of dichloromethane was followed by removal of the solvent to
mmol) were stirred for 30 min at room temperature in 3 mL
of CH2Cl2. Filtration over Celite and washing with 0.5-1.0 mL
of dichloromethane was followed by removal of the solvent to
give 52 mg (45%) of the product. Anal. Calcd for C74H46N2-
BF24PPd: C, 56.71; H, 2.96; N, 1.79. Found: C, 56.74; H, 3.15;
3
N, 1.79. 1H NMR (CD2Cl2, 500 MHz): δ 7.77 (d, J HH ) 8.6,
3
H-4), 7.58 (H-9), 7.57 (H-5), 7.34 (H-8), 7.00 (d, J HH ) 8.6,
3
3
give 61 mg (65%) of the product. Anal. Calcd for C89H79NBF24
-
H-7), 6.93 (d, J HH ) 7.1, H-L5), 6.79 (t, J HH ) 7.7, H-L4),
3
3
4
PPd: C, 60.50; H, 4.51; N, 0.79. Found: C, 60.73; H, 4.56; N,
6.21 (t, J HH ) 7.9, H-L3), 5.95 (t, J HH ) J PH ) 7.5, H-L2),
0.91. 1H NMR (CD2Cl2, 500 MHz): δ 8.18 (d, 3J HH ) 8.6, H-4),
2
2
4
4.27 (bd, J HH ) 12.6, H-L7), 3.84 (dd, J HH ) 14.1, J PH) 2.4,
H-L7), 2.76 (bs, CH3-L8), 2.70 (bs, CH3-L9). 13C NMR (CD2-
Cl2,125 MHz): δ 148.2 (C-L6), 146.2 (C-1), 145.0 (C-L1), 138.0
(C-L2), 136.0 (C-3), 132.0 (C-2), 131.6 (C-4), 130.9 (C-9), 129.1
(C-10), 128.3 (C-7), 126.3 (C-L3), 126.2 (C-L4), 125.2 (C-5),
123.9 (C-L5), 107.3 (C-6), 71.4 (C-L7), 51.7 (C-L9), 50.5 (C-
L8). 31P NMR (CD2Cl2, 202 MHz): δ 44.5 (s). IR (Golden
Gate): 3063 cm-1 (C-H arom.), 2231 cm-1 (CtN). IR (Nujol):
2240 cm-1 (CtN). MS (ESI): 703.0 (M+ - BArF, 80%), 735.1
(M+ + MeOH - BArF, 100%).
3
7.82 (H-5), 7.81 (H-10), 7.34 (t, J HH ) 7.3, H-9), 7.24 (H-6),
3
3
6.80 (d, J HH ) 7.3, H-L5), 6.72 (t, J HH ) 7.5, H-8), 6.64 (t,
3J HH ) 7.3, H-L4), 6.25 (d, J HH ) 8.3, H-7), 6.11 (t, J HH
7.7, H-L3), 6.05 (t, J HH ) J PH ) 7.7, H-L2), 4.59 (d, J HH
)
)
3
3
3
4
2
13.3, H-L7), 3.46 (d, 2J HH ) 13.3, H-L7), 3.19 (s, CH3-L8), 2.62
(s, CH3-L9), 1.05 (s, 18 H, C(CH3)3), 1.04 (s, 18 H, C(CH3)3).
13C NMR (CD2Cl2, 125 MHz): δ 150.4 (C-L1), 150.3 (C-1), 144.5
(C-L6), 137.5 (C-L2), 134.6 (C-3), 132.1 (C-2), 131.1 (C-4), 129.6
(C-9), 128.5 (C-10), 127.8 (C-7), 127.7 (C-5), 127.2 (C-L3), 125.8
(C-L4), 124.1 (C-L5), 105.4 (C-6), 72.8 (C-L7), 51.5 (C-L8), 48.9
(C-L9), 35.1 (C(CH3)3), 31.1 (C(CH3)3). 31P NMR (CD2Cl2, 202
MHz): δ 39.5 (s). MS (ESI): 902.19 (M+ - BArF, 100%).
Syn th esis of P d Cl(C6H4CH2NMe2)(1d ), 18. To a mixture
of 35.7 mg of [Pd(µ-Cl)(C6H4CH2NMe2)]2 (0.065 mmol) and 60
mg of 1d (0.129 mmol) was added 2 mL of CH2Cl2. The solution
was stirred for 30 min at room temperature. After removal of
the solvent the crude product was recrystallized from toluene/
pentane. Yield: 76.1 mg (80%). Anal. Calcd for C42H34N2-
PClPd: C, 68.21; H, 4.63; N, 3.79. Found: C, 68.14; H, 4.83;
Hyd r osilyla tion of Styr en e. To a mixture of 0.8 mg of
[Pd(µ-Cl)(η3-C3H5)]2 (2.1 µmol) and 8.2 µmol of MOP ligand was
added 0.5 mL of styrene (4.33 mmol) and, after cooling to 5
°C, 0.53 mL of HSiCl3 (5.3 mmol). The reaction solution was
stirred at 5 °C and the product formation monitored by 1H
NMR.
Ack n ow led gm en t. P.S.P. thanks the Swiss Na-
tional Science Foundation, the “Bundesamt fu¨r Bildung
und Wissenschaft”, and the ETHZ for financial support.
A.A. thanks MURST for a grant. We also thank J ohnson
Matthey for the loan of precious metals.
3
N, 3.58. 1H NMR (CD2Cl2, 500 MHz): δ 8.13 (d, J HH ) 8.6,
3
H-7), 7.82 (d, J HH ) 8.3, H-10), 7.63 (H-4), 7.61 (H-9), 7.51
3
3
(H-8), 7.04 (d, J HH ) 8.6, H-5), 6.82 (d, J HH ) 7.1, H-L5),
6.61 (H-L4), 6.05 (t, J HH ) 7.7, H-L3), 5.76 (d, J HH ) 4J PH
)
3
3
2
2
7.1, H-L2), 4.04 (d, J HH ) 13.5, H-L7), 3.61 (dd, J HH ) 13.5,
4J PH ) 3.2, H-L7), 2.83 (d, 4J PH ) 2.6, CH3-L8), 2.67 (d, 4J PH
)
Su p p or tin g In for m a tion Ava ila ble: Text giving experi-
mental details and a full listing of crystallographic data for 9,
including tables of positional and isotropic equivalent displace-
ment parameters, anisotropic displacement parameters, cal-
culated positions of the hydrogen atoms, bond distances, bond
angles, and torsional 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.
1.7, CH3-L9). 13C NMR (CD2Cl2, 125 MHz): δ 151.9 (C-L1),
149.9 (C-L6), 142.9 (C-1), 138.7 (C-L2), 134.9 (C-3), 133.0 (C-
2), 130.5 (C-7), 129.3 (C-9), 129.3 (C-4), 128.1 (C-10), 127.1 (C-
5), 124.8 (C-L3), 123.9 (C-L4), 122.3 (C-L5), 118.9 (CtN), 112.4
(C-6), 73.6 (C-L7), 51.7 (C-L8), 49.8 (C-L9). 31P NMR (CD2Cl2,
202 MHz): δ 49.7 (s). IR (Golden Gate): 3053 cm-1 (C-H
arom.), 2224 cm-1 (CtN). MS (HRMALDI): 703.1494 (M+
-
Cl, 25%, calc 703.1503).
Syn th esis of [P d (C6H4CH2NMe2)(1d )](BAr F ), 19. A 54.6
mg amount of 18 (0.074 mmol) and 65.4 mg of NaBArF (0.074
OM0496535