Dinuclear [{(π-C3H5)M(PR3)} 2(μ-X)]Y complexes of nickel and palladium

Article abstract of DOI:10.1021/om050020f

The double halide-bridged π-allyl complexes {(η³-C ₃H₅)M(μ-X)}₂ (M = Ni, Pd; X = Cl, Br) resist halide abstraction by thallium salts of weakly coordinating anions Y = PF ₆, B(C₆F₅)₄, and B{C ₆H₃(CF₃)₂}₄ in noncoordinating CH₂Cl₂. In the presence of a bulky phosphine (PⁱPr₃, P^tBu₃) or when 2 equiv of (η³-C₃H₅)M(PR₃)X is reacted with TlY, one of the halide ions is replaced to afford the ionic dinuclear, single halide-bridged complexes [{(η³-C ₃H₅)M-(PR₃)}₂(μ-X)]Y (M = Ni, X = Br (6, 7); M - Pd, X = Cl (8, 9) and Br (10, 11)), which do not react with further TlY. The corresponding complexes with Y = Al{OC(CF₃) ₃}₄ have also been prepared. In addition, it has been found that the dinuclear palladium complexes, but not the nickel derivatives, are also stable for Y = OTf. According to NMR the complexes represent a mixture of diastereomers in solution. For [{(η³-C₃H ₅)Ni(PⁱPr₃)}₂(μ-Br)] [Al{OC(CF₃)₃}₄] (6c) and [{(η³- C₃H₅)Pd(P^tBu₃)}₂(μ-Br) ][B(C₆F₅)₄] (11b) the crystal structures have been determined. The reaction of (η³-C₃H ₅)M(PMe₃)X with TlY affords a mixture of [(η³-C₃H₅)M-(PMe₃) ₂]Y (described for M = Ni, Y = PF₆ (12) and M - Pd, Y = PF₆ (13)) and the starting phosphine-free {(η³-C ₃H₅)M(μ-X)}₂.

Full text of DOI:10.1021/om050020f

Organometallics 2005, 24, 3907-3915
3907
Dinuclear [{(π-C3H5)M(PR3)}2(µ-X)]Y Complexes of Nickel
and Palladium†
Davide Alberti, Richard Goddard, and Klaus-Richard Po¨rschke*
Max-Planck-Institut fu¨r Kohlenforschung, D-45466 Mu¨lheim an der Ruhr, Germany
Received January 12, 2005
The double halide-bridged π-allyl complexes {(η3-C3H5)M(µ-X)}2 (M ) Ni, Pd; X ) Cl, Br)
resist halide abstraction by thallium salts of weakly coordinating anions Y ) PF6, B(C6F5)4,
and B{C6H3(CF3)2}4 in noncoordinating CH2Cl2. In the presence of a bulky phosphine
(PiPr3, PtBu3) or when 2 equiv of (η3-C3H5)M(PR3)X is reacted with TlY, one of the halide
ions is replaced to afford the ionic dinuclear, single halide-bridged complexes [{(η3-C3H5)M-
(PR3)}2(µ-X)]Y (M ) Ni, X ) Br (6, 7); M ) Pd, X ) Cl (8, 9) and Br (10, 11)), which do not
react with further TlY. The corresponding complexes with Y ) Al{OC(CF3)3}4 have also been
prepared. In addition, it has been found that the dinuclear palladium complexes, but not
the nickel derivatives, are also stable for Y ) OTf. According to NMR the complexes represent
a mixture of diastereomers in solution. For [{(η3-C3H5)Ni(PiPr3)}2(µ-Br)][Al{OC(CF3)3}4] (6c)
and [{(η3-C3H5)Pd(PtBu3)}2(µ-Br)][B(C6F5)4] (11b) the crystal structures have been deter-
mined. The reaction of (η3-C3H5)M(PMe3)X with TlY affords a mixture of [(η3-C3H5)M-
(PMe3)2]Y (described for M ) Ni, Y ) PF6 (12) and M ) Pd, Y ) PF6 (13)) and the starting
phosphine-free {(η3-C3H5)M(µ-X)}2.
Introduction
Ni(PR3)(µ-X)AlR′nX3-n (4), of which the derivative (η3-
C3H5)Ni(PCy3)(µ-Cl)AlMeCl2 (4a) has been character-
ized by X-ray structure analysis.2 Complexes of this type
are most active for the catalytic dimerization of propene,
and highest activity paired with highest selectivity has
been observed for a PtBuiPr2 modified catalyst. The
halide bridges in 3 and 4 are weaker than in 1, and they
are cleaved with cod and CO, as well as PR3, to give
rise to inactive ionic complexes [(η3-C3H5)NiL2]-
[R′nAlX4-n] (5) with tightly coordinated ligands L (Scheme
1).1
(η3-allyl)Ni-halide complexes are important precursor
complexes for homogeneous catalysts. The halide bridges
in the pristine dimeric {(η3-C3H5)Ni(µ-X)}2 (X ) Cl, Br,
I; 1) are certainly relatively strong and resist, for
instance, cleavage by alkenes such as ethene and 1,5-
cyclooctadiene (cod) or by CO, and accordingly the
catalytic activity of {(η3-C3H5)Ni(µ-X)}2 for olefin oligo-
merization is low. However, the activity increases
considerably by addition of Lewis acids and phosphines.1
Indeed, reaction of 1 with 1 equiv of phosphine per
nickel results in cleavage of both halide bridges to yield
mononuclear complexes (η3-C3H5)Ni(PR3)X (2), which
are more active than the pristine 1. Addition of alumi-
num halides R′nAlX3-n (n ) 0-2) to 1 also cleaves the
Ni-X-Ni bridges, but gives red oily, polar adducts (η3-
C3H5)Ni(R′nAlX4-n) (R′ ) alkyl, X; 3), which have a
catalytic activity toward ethylene and propylene several
orders higher than that of the starting 1. The structure
of 3 is likely to be square-planar with the (η3-C3H5)Ni
It is important to emphasize that the complexes 2-4
are only precursor complexes of the true catalytically
active species, which has actually been identified as a
nickel hydride. This is formed in a stoichiometric
reaction by π-σ-allyl isomerization and insertion of
propyne into the Ni-C bond, followed by â-H abstrac-
tion (eq 1).
moiety chelated by R′nAlX4-n
,
i.e., (η3-C3H5)Ni-
An initially invoked ionic structure
1e
(µ-X)2AlR′nX2-n
.
[(η3-C3H5)Ni][AlR′nX4-n
]
has since been discarded.
1a,b
Reactions of either 2 with an aluminum halide or 3
with a phosphine result in isolable adducts (η3-C3H5)-
Other important reactions involving the (η3-allyl)-
M(PR3)X unit (M ) Ni, Pd) are the (η3-allyl)Ni(PiPr3)X/
AgY (Y ) BF4, ClO4, CF3SO3) catalyzed cyclization of
1,5- and 1,6-dienes3 and the (η3-C3H5)Ni(PMe3)Cl/
AgBF4-
† Dedicated to Gu¨nther Wilke on the occasion of his 80th birthday
(February 23, 2005), in recognition of his seminal studies in metal-
allyl chemistry.
(1) (a) Birkenstock, U.; Bo¨nnemann, H.; Bogdanovic, B.; Walter, D.;
Wilke, G. Adv. Chem. Ser. 1968, 70, 250. (b) Bogdanovic, B.; Wilke, G.
Brennstoff-Chemie 1968, 49, 323. (c) Bogdanovic, B.; Henc, B.; Kar-
mann, H.-G.; Nu¨ssel, H.-G.; Walter, D.; Wilke, G. Ind. Eng. Chem.
1970, 62, Nr. 12, p 34. (d) Bogdanovic, B.; Henc, B.; Lo¨sler, A.; Meister,
B.; Pauling, H.; Wilke, G. Angew. Chem. 1973, 85, 1013; Angew. Chem.,
Int. Ed. Engl. 1973, 12, 954. (e) Bogdanovic, B. Adv. Organomet. Chem.
1979, 17, 105. (f) Wilke, G. Angew. Chem. 1988, 100, 189; Angew.
Chem., Int. Ed. Engl. 1988, 27, 185.
(2) Bogdanovic, B.; Ilmaier, B.; Walter, D.; Wilke, G.; Kru¨ger, C.;
Tsay, Y.-H. 1972. Cited in ref 1d, Figure 3.
(3) Bogdanovic, B.; Galle, J.; Hoffman, N.; Wilke, G. Unpublished
(1972-1974). Cited in ref 1e, pp 113 and 127.
10.1021/om050020f CCC: $30.25 © 2005 American Chemical Society
Publication on Web 06/25/2005

3908 Organometallics, Vol. 24, No. 16, 2005
Alberti et al.
(TFPB, BArF),10 or Al{OC(CF3)3}4,11 we isolated single
halide-bridged, dinuclear complexes [{(η3-C3H5)M(PR3)}2-
(µ-X)]Y (X ) Cl, Br). Here we describe the structure and
reactions of these compounds. We have already reported
on related Pd complexes containing N-heterocyclic car-
bene ligands instead of phosphine.12 Very recently, the
cationic metal-pair complexes have also been the subject
of a patent.13
Scheme 1
Results and Discussion
While the electrical conductivity of {(η3-allyl)M(µ-X)}2
solutions is negligible, as was shown for {(η3-C3H5)Pd-
(µ-Cl)}2 in benzene and DMSO/H2O,14 it is noticeable
for (η3-C3H5)M(PR3)X complexes (for 10-2 M (η3-C3H5)Pd-
(PiPr3)X, X ) Cl and Br, in DMSO, Λ ≈ 0.3 S‚cm2‚mol-1),
suggesting slight self-ionization according to eq 2a or
2b. Ligand exchange processes of (η3-C3H5)M(PR3)X
complexes have been previously proposed, but have so
far not been specified.15 In fact, partial self-ionization
according to eq 2b is also evident from the ESIpos mass
spectra of the complexes (η3-C3H5)M(PR3)X (M ) Ni, Pd;
catalyzed dimerization of methylacrylate.4 In the latter
case the formation of intermediate (η3-C3H5)Ni(PMe3)-
BF4 was proposed, which is closely related to 4. Japa-
nese authors have reported a (η3-C3H5)Pd(PR3)Cl/AgY
or TlY (Y ) e.g., BF4, PF6, SbF6, ClO4) catalyzed
coupling of vinylarenes with terminal alkenes. They
presume that the complex anion leaves an uncoordi-
nated site at palladium.5 Only recently have Widenhoe-
fer et al. suggested that the 1,6-diene cycloisomerization
catalyst generated by reaction of (η3-C3H5)Pd(PCy3)Cl
with NaB{3,5-C6H3(CF3)2}4 and HSiEt3 in CH2Cl2 con-
tained a potential vacant coordination site on palladium
that could be occupied by some weakly coordinated
ligand such as solvent, water, or silane.6
i
t
R ) Pr, Bu; X ) Cl, Br, OTf), which display, besides
the expected mononuclear ions [M - X]+, for the PiPr3-
ligated compounds intense signals of the dinuclear ions
[2M - X]+.
Despite all these studies, there is so far no compelling
evidence for the occurrence of highly electron deficient,
ionic 12e [(η3-C3H5)M]Y or 14e [(η3-C3H5)ML]Y com-
plexes with a noncoordinating counterion Y,7 but it is
clear that such complexes would be of high potential
interest.8 In an attempt to synthesize complexes of the
type [(η3-C3H5)M(PR3)]Y with weakly or noncoordinat-
ing ions, such as Y ) PF6, B(C6F5)4,9 B{3,5-C6H3(CF3)2}4
When the complexes (η3-C3H5)M(PR3)X (X ) Cl, Br)
are reacted with an excess of thallium reagent TlY of a
weakly coordinating anion (Y ) PF6, B(C6F5)4, and
B{C6H3(CF3)2}4) in CH2Cl2 at -30 °C, only 0.5 equiv of
the TlY is consumed to form TlX. The resulting products
are the ionic dinuclear complexes [{(η3-C3H5)M(PR3)}2-
(µ-X)]Y (6-11), in which the remaining halide ion
bridges the two metal centers. The same products are
obtained when the dinuclear {(η3-C3H5)M(µ-X)}2 are
reacted with a stoichiometric amount of PR3 and TlX
in a one-pot reaction. The toxic TlY reagents are
preferred over the more reactive AgY reagents because
of the avoidance of side-reactions. The derivatives with
Y ) Al{OC(CF3)3}4 have been prepared by the reaction
of (η3-C3H5)M(PR3)X with LiAl{OC(CF3)3}4, demonstrat-
ing also that M′X salts (M′ ) Li, Tl, Ag) are readily
eliminated (eq 3).
(4) (a) Sperling, K. Dissertation (G. Wilke), Universita¨t Bochum,
Germany, 1983. (b) Wilke, G.; Sperling, K.; Stehling, L. German Patent
DOS 3.336.691, 1983; US Patent 4.594.447, 1986. (c) Wilke, G. Proc.
5th IUPAC Symp. Org. Synth. 1984; Blackwell: Oxford; 1985; p 1.
(5) Hattori, S.; Munakata, H.; Tatsuoka, K.; Shimizu, T. US Patent
3.803.254, 1974.
(6) (a) Widenhoefer, R. A.; Perch, N. S. Org. Lett. 1999, 1, 1103. (b)
Kisanga, P.; Widenhoefer, R. A. J. Am. Chem. Soc. 2000, 122, 10017.
(c) Widenhoefer, R. A. Acc. Chem. Res. 2002, 35, 905.
(7) (a) Chauvin, Y.; Olivier, H. In Applied Homogeneous Catalysis
with Organometallic Compounds; Cornils, B., Herrmann, W. A., Eds.;
VCH: Weinheim, 1996; p 258. (b) Elschenbroich, C. Organometallche-
mie, 4th ed.; Teubner: Stuttgart, 2003; p 651.
(8) Several ionic or neutral, seemingly three-coordinate 14e NiII- and
PdII-organyl complexes that feature an additional â-H agostic interac-
tion have been described in recent years. (a) [(tBu2PC2H4PtBu2)Ni-
(C2H5)][BF4]: Conroy-Lewis, F. M.; Mole, L.; Redhouse, A. D.; Litster,
S. A.; Spencer, J. L. J. Chem. Soc., Chem. Commun. 1991, 1601. (b)
(R3P)Pd(Ar)X (X ) Br, I, OTf): Stambuli, J. P.; Bu¨hl, M.; Hartwig, J.
F. J. Am. Chem. Soc. 2002, 124, 9346. Stambuli, J. P.; Incarvito, C.
D.; Bu¨hl, M.; Hartwig, J. F. J. Am. Chem. Soc. 2004, 126, 1184. (c)
[(R-diimine)MR][BAr4] (M ) Ni, Pd; R ) Et, Pr): Tempel, D. J.;
Johnson, L. K.; Huff, R. L.; White, P. S.; Brookhart, M. J. Am. Chem.
Soc. 2000, 122, 6686. Shultz, L. H.; Tempel, D. J.; Brookhart, M. J.
Am. Chem. Soc. 2001, 123, 11539. Leatherman, M. D.; Svejda, S. A.;
Johnson, L. K.; Brookhart, M. J. Am. Chem. Soc. 2003, 125, 3068. (d)
(â-diketiminate)NiR (R ) Et, Pr): Kogut, E.; Zeller, A.; Warren, T.
H.; Strassner, T. J. Am. Chem. Soc. 2004, 126, 11984.
(10) (a) Nishida, H.; Takada, N.; Yoshimura, M.; Sonoda, T.;
Kobayashi, H. Bull. Chem. Soc. Jpn 1984, 57, 2600. (b) Bahr, S. R.;
Boudjouk, P. J. Org. Chem. 1992, 57, 5545.
-
(11) Al(ORF)4
: Barbarich, T. J.; Miller, S. M.; Anderson, O. P.;
Strauss, S. H. J. Mol. Catal. 1998, 128, 289. Ivanova, S. M.; Nolan, B.
G.; Kobayashi, Y.; Miller, S. M.; Anderson, O. P.; Strauss, S. H. Chem.
Eur. J. 2001, 7, 503. Krossing, I. Chem. Eur. J. 2001, 7, 490.
(12) Ding, Y.; Goddard, R.; Po¨rschke, K.-R. Organometallics 2005,
24, 439.
(13) Goodall, B. L.; Petoff, J. L.; Shen, H. US Patent Application
2005/0043494 A1.
(9) (a) Massey, A. G.; Park, A. J.; Stone, F. G. A. Proc. Chem. Soc.
1963, 212. (b) Massey, A. G.; Park, A. J. J. Organomet. Chem. 1964,
2, 245. (c) Massey, A. G.; Park, A. J. J. Organomet. Chem. 1966, 5,
218. (d) Massey, A. G.; Park, A. J. Organometallic Synthesis; King, R.
B.; Eisch, J. J., Eds.; Elsevier: New York, 1986; Vol. 3, p 461.
(14) (a) Khvostik, G. M.; Poddubnyi, I. Y.; Sokolov, V. N.; Tsereteli,
I. Y. Russ. J. Phys. Chem. 1970, 44, 872. (b) Khan, B. T.; Mohan, K.
M.; Zakeeruddin, S. M. Metallorg. Khim. 1990, 3, 743.
(15) Vrieze, K.; MacLean, C.; Cossee, P.; Hilbers, C. W. Rec. Trav.
Chim. Pays-Bas 1966, 85, 1077.

Dinuclear Complexes of Ni and Pd
Organometallics, Vol. 24, No. 16, 2005 3909
plexes the OTf anion competes with the bridging halide
for coordination at the metal center. Thus, eq 4 repre-
sents an equilibrium which lies on the left for Ni and
on the right for Pd.
The [{(η3-C3H5)M(PR3)}2(µ-X)]Y complexes 6-11 form
yellow to red microcrystals, and only for 6c and 11b
were we able to obtain single crystals suitable for X-ray
structure analysis (see below). In general, the Pd
complexes in this series are thermally more stable than
the corresponding Ni complexes, and the PiPr3 deriva-
tives are more stable than those containing PtBu3. Thus,
the PiPr3-ligated Pd complexes 8 and 10 are stable at
ambient temperature over prolonged periods, whereas
the PtBu3-ligated Ni complexes 7 must be handled at
-30 °C. The remaining complexes 6, 9, and 11 are
briefly stable at ambient temperature.
No meaningful EI mass spectra have been obtained
for 6-11. In the ESIpos mass spectra (CH2Cl2) of the
[{(η3-C3H5)Ni(PiPr3)}2(µ-Br)]+ complexes 6 both the di-
nuclear cation (m/e 597) and the halide-free mono-
nuclear [(η3-C3H5)Ni(PiPr3)]+ (m/e 259, undergoing loss
of H atoms) are found as prominent ions in the spectra.
An even stronger peak for the dinuclear cation is found
for the Pd derivatives 10, where the dinuclear cation
[{(η3-C3H5)Pd(PiPr3)}2(µ-Br)]+ (m/e 693) but also [(η3-
C3H5)Pd(PiPr3)]+ (m/e 307) may represent the base ion.
For the other Ni and Pd complexes, that is, when either
PiPr3 is replaced with PtBu3 (7 and 11) and/or bromide
is replaced with chloride (8 and 9), the base ion is mostly
given by [(η3-C3H5)M(PR3)]+, while the intensity of the
dinuclear cation diminishes to 5-20%. In view of the
fact that the mononuclear (η3-C3H5)M(PR3)X and the
dinuclear derivatives [{(η3-C3H5)M(PR3)}2(µ-X)]Y in each
case give rise to mono- and dinuclear cations in the
ESIpos mass spectra, their distinction is hardly possible
by this method.
A special situation arises for the weakly nucleophilic
trifluoromethylsulfonate (triflate, OTf) anion. The Ni
complexes (η3-C3H5)Ni(PiPr3)X (X ) Cl, Br) react with
1 equiv of TlOTf at 0 °C to give (η3-C3H5)Ni(PiPr3)-
(OTf)16a with full replacement of the halide by the
triflate anion (the PtBu3 derivative appears unstable at
-30 °C). However, the synthesis of halide-bridged,
dinuclear Ni triflates [{(η3-C3H5)Ni(PR3)}2(µ-X)]OTf has
failed, and it seems that in this case the OTf ion would
attack Ni to cleave the Ni-µ-X-Ni bridge and give
equal amounts of (η3-C3H5)Ni(PR3)X and (η3-C3H5)Ni-
(PR3)(OTf). In fact, from diethyl ether solutions contain-
ing equal amounts of (η3-C3H5)Ni(PiPr3)X and (η3-
C3H5)Ni(PiPr3)(OTf) the two complexes crystallize
1
unchanged at low temperature. At -80 °C the H, 13C,
and 31P NMR spectra of this mixture show the reso-
nances of the individual complexes, whereas at ambient
temperature equilibration occurs due to an exchange
process.
In contrast, the Pd complexes (η3-C3H5)Pd(PR3)Cl (R
i
t
) Pr, Bu) react with an excess of TlOTf to give a
mixture of the mononuclear Pd-triflates (η3-C3H5)Pd-
(PR3)(OTf) (R ) iPr,16b tBu) and the (nonisolated)
chloride-bridged triflate salts [{(η3-C3H5)Pd(PR3)}2-
(µ-Cl)]OTf, while the reaction of the bromide (η3-C3H5)Pd-
(PiPr3)Br with TlOTf at -30 °C stops at the stage of
the dinuclear 10a. Here, the pure (η3-C3H5)Pd(PR3)(OTf)
complexes seem only to be accessible when the more
reactive AgOTf is used.16b Nevertheless, the reactions
with an excess of TlOTf indicate that the Pd-µ-Cl-Pd
bridges in the title complexes are more readily cleaved
by the OTf anion than Pd-µ-Br-Pd bridges. The
π-allylpalladium bromides (η3-C3H5)Pd(PR3)Br (R ) iPr,
tBu) react with 0.5 equiv of TlOTf according to eq 3 to
yield the dinuclear bromide-bridged 10a and 11a. These
complexes were also prepared by mixing equal amounts
of (η3-C3H5)Pd(PR3)Br and (η3-C3H5)Pd(PR3)OTf (eq 4).
It appears that in [{(η3-C3H5)M(PR3)}2(µ-X)]OTf com-
Attempts to synthesize derivatives of the PiPr3- and
PtBu3-ligated complexes 6-11 with the much smaller
PMe3 ligand were unsuccessful. Reaction of (η3-C3H5)M-
(PMe3)X (M ) Ni, Pd; X ) Cl, Br) with TlY (Y ) OTf,
PF6, B(C6F5)4, B{3,5-C6H3(CF3)2}4) or LiAl{OC(CF3)3}4
in CH2Cl2 at 0 °C resulted in a redistribution of the
PMe3 ligands to yield a mixture of [(η3-C3H5)M(PMe3)2]Y
(of which the PF6 salts 12 and 13 have been described
in the Experimental Part) and phosphine-free {(η3-
C3H5)M(µ-X)}2 (eq 5). It seems likely that in the course
of the reaction the dinuclear [{(η3-C3H5)M(PMe3)}2-
(µ-X)]Y is intermediately formed, but that it stabilizes
to give the bis(phosphine) complex [(η3-C3H5)M(PMe3)2]Y.
The formation of such complexes with vicinal phos-
phine ligands is less favored (PiPr3) or even impossible
(PtBu3) for the more bulky phosphines, which explains
why for these phosphines dinuclear [{(η3-C3H5)M(PR3)}2-
(µ-X)]Y is isolated.
(16) (a) Proft, B. Dissertation, Universita¨t Du¨sseldorf, 1993. (b)
Krause, J.; Goddard, R.; Mynott, R.; Po¨rschke, K.-R. Organometallics
2001, 20, 1992.
There have been relatively few dinuclear M-µ-X-M
(M ) Ni, Pd, Pt) complexes with single halide bridges.

3910 Organometallics, Vol. 24, No. 16, 2005
Alberti et al.
The spectra of mononuclear (η3-C3H5)Pd(PR3)X and
the corresponding dinuclear ionic complexes 8-11 are
much better resolved than those of the Ni derivatives,
and for the Pd complexes resolution increases on going
from tBu to iPr and from Cl to Br. While in the ambient
temperature 1H NMR spectra of (η3-C3H5)Pd(PiPr3)X (X
) Cl, Br, OTf) in THF-d8 the syn and anti allyl protons
trans to X show line-broadening or coalescence due to
selective π-σ-allyl rearrangement with exchange of
these protons,16b the resonances are sharp for the CD2-
Cl2 solution and, moreover, the isopropyl Me groups are
diastereotopic, indicative of a rigid chiral structure.
Resolved allyl resonances and diastereotopic Me groups
are also found for the dinuclear [{(η3-C3H5)Pd(PiPr3)}2-
(µ-X)]+ complexes 8 and 10 at ambient temperature, and
this can be taken as evidence for an essentially nondy-
namic coordination of the ligands at the Pd centers. For
the [{(η3-C3H5)Pd(PtBu3)}2(µ-X)]+ complexes 9 and 11
well-resolved spectra are observed at -30 °C, whereas
resonances are broad at ambient temperature.
The reaction of {(η3-C3H5)Pd(µ-Cl)}2 with cyclohexanone
oxime affords the neutral, asymmetrical addition com-
pound (η3-C3H5)(Cl)Pd(µ-Cl)Pd(η3-C3H5)(C6H10NOH) (A),
in which one of the initially two chloride bridges is
cleaved and the other is retained.17 Further examples
are given by the ionic [{2,6-(Me2NCH2)2C6H3Pd}2(µ-Cl)]-
i
BF4 (B)18 and [{Me2C2(NC6H3 Pr2)2PtMe}2(µ-Cl)]BF4
(C),19 for which structures with approximate C2 point
symmetry of the cation have been observed. Complexes
6-11 are most closely related to the concurrently
reported complexes [{(η3-C3H5)Pd(NHC)}2(µ-X)]Y, hav-
ing carbene instead of phosphine ligands, and of which
[{(η3-C3H5)PdC(N(tBu)CH)2}2(µ-Cl)]PF6 (D) has been
structurally characterized.12
1
If one compares the H and 13C NMR spectra of the
[{(η3-C3H5)Pd(PR3)}2(µ-X)]+ cations with those of the
neutral (η3-C3H5)Pd(PR3)X precursors, there is a distinct
shift of the allyl resonances to lower field. However, the
shift differences between the [{(η3-C3H5)Pd(PR3)}2-
(µ-X)]+ cations bearing the same phosphine are only
marginal for the different halides (Cl vs Br). Comparison
of the shift data and the dynamic properties of the
various complexes leads us to conclude that (a) in (η3-
C3H5)Pd(PiPr3)X the donor strength of bromide toward
Pd is greater than that of chloride, in agreement with
the lower electronegativity and the larger polarizability
of bromide, (b) the donor strength of the halide toward
Pd is weaker in the dinuclear complexes than in the
corresponding mononuclear complexes, and (c) the allyl
groups are more tightly coordinated in the (dinuclear)
cationic complexes than in the (mononuclear) neutral
compounds.
For an individual cation of the [{(η3-C3H5)M(PR3)}2-
(µ-X)]Y complexes the allyl and PR3 resonances are, as
expected, rather independent of Y, but this is not always
the case. In particular, the OTf and BArF salts are
sometimes at marked variance to the other complexes
of the series (see in Table S2, for instance, complexes
11a and 11c versus 11b,d). It appears that ion-pairing
is significant in solution and that the BArF anion
imposes an anisotropic effect on the cation. In the case
of the OTf complexes ion-pairing should foster the
equilibrium process according to eq 4, which explains
for 11a the deviations from the expected resonances.
NMR Spectra. Selected solution 1H, 13C, and 31P
NMR data for the neutral mononuclear (η3-C3H5)M-
(PR3)X complexes and the dinuclear cations of complexes
6-11 in CD2Cl2 are listed in Table 1. More comprehen-
sive data listings (Tables S1 and S2) are contained in
the Supporting Information. Spectral data of the anions
OTf (δ(C) 119.7, J(CF) ) 320 Hz), Al{OC(CF3)3}4 (δ(C)
120.5, J(CF) ) 293 Hz), and PF6 (δ(P) -144.7, J(PF) )
711 Hz) (at -80 °C) are not quoted further. In the cases
where 11B NMR spectra have been recorded, the B(C6F5)4
anion gives rise to a resonance at δ(B) -16.7 and the
BArF anion at δ(B) -6.7.
The formally square-planar mononuclear (η3-C3H5)M-
(PR3)X complexes are chiral, and this gives rise to five
1H and three 13C allyl signals for the rigid structures.
Similar principal resonances are expected for the di-
nuclear [{(η3-C3H5)M(PR3)}2(µ-X)]+ cations, but these
resonances, as well as those of the phosphine ligands,
can be doubled due to the presence of diastereomers.12
A detailed description of the allyl resonances of (η3-
C3H5)Pd(PiPr3)Cl (in THF solution) and the factors that
govern the chemical shifts and dynamic properties can
be found in ref 16b.
For the [{(η3-C3H5)Ni(PiPr3)}2(µ-Br)]+ complexes 6 the
allyl 1H and 13C NMR resonances are somewhat broad-
ened at ambient temperature, indicative of a slow
dynamic process. For the PtBu3-ligated 7 the spectra are
very broad between ambient temperature and -30 °C,
and this can be explained by the occurrence of various
dynamic processes such as π-σ-allyl isomerization and
phosphine dissociation. There is generally little differ-
ence between the spectra of (η3-C3H5)Ni(PR3)Br and the
dinuclear ionic derivatives [{(η3-C3H5)Ni(PR3)}2(µ-Br)]Y.
When the temperature is lowered from 25 to -30 or
-80 °C, the [{(η3-C3H5)M(PR3)}2(µ-X)]Y complexes, for
which at least two of the stabilizing parameters Pd >
Ni, iPr3P > tBu3P, and Br > Cl are fulfilled and, hence,
relatively rigid structures around the metal centers with
enantiomeric stability can be assumed, show a splitting
1
of the allyl H and 13C resonances. The effect is most
obvious for the syn proton trans to P and both anti
protons (but not for the syn proton trans to halide), the
meso carbon, and the methylene carbon trans to P.
Moreover, in the 31P NMR spectra the singlet is split
into two very close lines of equal intensity. While for
most complexes the effect has been observed at -80 °C,
it is found for most BArF salts already at -30 °C (9c,
(17) The Pd-Cl-Pd angle in A is 107.3°. Kitano, Y.; Kajimoto, T.;
Kashiwagi, M.; Kinoshita, Y. J. Organomet. Chem. 1971, 33, 123.
(18) The Pd-Cl-Pd angle in B is 134.8°. Terheijden, J.; van Koten,
G.; Grove, D. M.; Vrieze, K.; Spek, A. L. J. Chem. Soc., Dalton Trans.
1987, 1359.
(19) Albano, V. G.; Di Serio, M.; Monari, M.; Orabona, I.; Panunzi,
A.; Ruffo, F. Inorg. Chem. 2002, 41, 2672.

Dinuclear Complexes of Ni and Pd
Organometallics, Vol. 24, No. 16, 2005 3911
Table 1. NMR Data of Selected [{(η3-C3H5)M(PR3)}2(µ-X)]Y Complexes 6-11 and of Reference Compoundsa
Allyl
Hanti
2.87, 1.79c
2.98, 2.01
2.95, 1.86
PR3
δ(H)
Hsyn
3.95, 2.85c
4.29, 3.07
3.80, 3.70
d
4.53, 3.54
4.57, 3.52
4.51, 4.13
4.69, 4.33
4.58, 3.74
4.58, 3.71
4.61, 4.33
4.69, 4.55
δ(C)
Cterm
δ(H)
δ(C)
Hmeso
Cmeso
PCH
Me
PC
Me
δ(P)
39.8c
39.5, 39.3
70.1
61.6
53.3
51.6, 51.5
82.5
85.0
52.9
51.2, 51.1
85.7
84.8, 84.7
(C3H5)Ni(PiPr3)Br
6ac (Y ) B(C6F5)4)
(C3H5)Ni(PtBu3)Brc
7bb (Y ) BArF)
5.24c
5.35
5.22
108.3
110.2
104.1
74.1, 46.8
74.9, 49.2
71.6, 51.6
d
80.2, 51.2
82.7, 52.5
81.9, 57.5
86.3, 58.1
79.4, 54.4
81.4, 55.9
81.0, 61.4
84.0, 62.0
2.32
2.16
1.33, 1.28
1.22, 1.18
1.45
1.69
1.29, 1.24
1.17
24.8
22.9
38.3
37.2
25.0
24.0
38.5
39.3
25.4
24.4
39.0
38.7
19.9
18.2, 18.1
32.3b
30.0
(C3H5)Pd(PiPr3)Cl
8bc (Y ) B(C6F5)4)
(C3H5)Pd(PtBu3)Clc
9bb (Y ) B(C6F5)4)
(C3H5)Pd(PiPr3)Br
10bc (Y ) B(C6F5)4)
(C3H5)Pd(PtBu3)Brb
11bc (Y ) B(C6F5)4)
5.41
5.50
5.42
5.53
5.37
5.45
5.34
5.43
3.53, 2.61
3.60, 2.77
3.67, 2.78
3.83, 2.98
3.46, 2.70
3.51, 2.88
3.60, 2.89
3.65, 3.05
116.5
117.8
113.6
115.2
116.0
117.5
112.7
113.8
2.41
2.28
20.0, 19.9
19.0, 18.9
33.8, 27.6
32.3
1.40
1.45
2.45
2.33
1.29, 1.24
1.20, 1.18
1.46
20.0
19.1, 19.0
32.5
1.41
34.3, 27.4
a Solvent CH2Cl2. Temperature 25 °C. For those 1H and 13C resonances that are split due to the resolution of diastereomers mean
values of the chemical shifts are given. Sh ) sharp, br ) broad. b Temperature -30 °C. c Temperature -80 °C. d The 1H and 13C allyl
resonances of the compounds are broad between -30 and 20 °C.
Figure 2. Structure of the cation of 11b. Selected bond
distances (Å), angles (deg), and dihedral angles (deg): Pd1-
Figure 1. Cation of 6c, viewed down the approximate
C1 ) 2.207(4), Pd1-C3 ) 2.133(4), Pd1-P1 ) 2.407(1),
2-fold axis of symmetry passing through the Br atom and
Pd1-Br ) 2.5431(4), Pd2-C4 ) 2.190(4), Pd2-C6 ) 2.151-
the midpoint between Ni1 and Ni2. Selected distances (Å),
(4), Pd2-P2 ) 2.409(1), Pd2-Br ) 2.5511(4); Pd1-Br-
angles (deg), and torsion angles (deg): Ni1-Br ) 2.3564-
Pd2 ) 119.63(2), P1-Pd1-Br ) 107.26(3), C1-Pd1-P1 )
(5), Ni2-Br ) 2.3674(5), Ni1-P1 ) 2.2248(8), Ni2-P2 )
167.5(1), C3-Pd1-Br ) 151.4(1), P2-Pd2-Br ) 101.61-
2.2244(7), Ni1-C1 ) 2.048(4), Ni1-C2A ) 1.998(5), Ni1-
(2), C4-Pd2-P2 ) 169.7(1), C6-Pd2-Br ) 154.2(1);
C3 ) 1.992(3), Ni2-C13 ) 2.051(3), Ni2-C14A ) 1.972-
P1,Pd1,Br,C1,C3/P2,Pd2,Br,C4,C6 ) 92.8(1), P1,Pd1,Br,C1,-
(4), Ni2-C15 ) 1.997(4); Ni1-Br-Ni2 ) 118.01(2), Br-
C3/Pd1,Br,Pd2 ) 97.9(1), P2,Pd2,Br,C4,C6/Pd1,Br,Pd2 )
Ni1-P1 ) 97.75(2), Br-Ni2-P2 ) 94.53(2); Ni1-Br-Ni2-
5.8(1).
P2 ) 154(1), Ni2-Br-Ni1-P1 ) 140(1).
another. The high symmetry is broken by the isopropyl
groups on the P atoms, which are rotated by 11° to one
10c, and 11c). The splittings can be attributed to the
presence of diastereomers arising from enantiomerically
another with respect to the 2-fold axis, presumably due
stable chiral centers. A similar observation has been
to packing forces, since the isopropyl groups on the two
made for the Pd derivatives with NHC ligands instead
P atoms are well separated.
of phosphines, and the phenomenon is discussed in ref
12 in more detail.
Figure 2 shows the structure of the cation of 11b,
which is made up of two [(η3-C3H5)Pd(PtBu3)] moieties
Crystal Structures of 6c and 11b. The structure
bridged likewise by a bromide ion. The meso C atoms
of the nickel complex 6c and that of the palladium
of the allyl groups are disordered equally over two
positions in the cation. Since the allyl groups create
stereogenic centers at Pd1 and Pd2, we must assume
complex 11b have been determined by single-crystal
X-ray analysis at 100 K (Tables S3-S10 and Figures
S1 and S2 in the Supporting Information). Both com-
that the crystal is composed of diastereomeric cations.
pounds are found to exist as discrete dinuclear cations
The Pd1-Br-Pd2 angle at 119.63(2)° is within the
and Al{OC(CF3)3}4 or B(C6F5)4 anions.
range of observed Pd-Cl-Pd angles for the comparable
The structure of the cation of 6c is shown in Figure
complexes A and B.17,18 Pd-Br-Pd angles of up to 180°
1. Despite an asymmetrical environment caused by the
crystal, which is chiral, the central part of the cation
(the two allyl groups, the two Ni and two P atoms, as
well as the Br atom) exhibits an approximate 2-fold axis
of symmetry (rms deviation 0.16 Å) that passes through
the Br atom and the midpoint of the two Ni atoms. The
are found in other complexes.20
Although the cation in 11b could in principle exhibit
Cs or C2 point symmetry (Ci is impossible on account of
the nonlinear Pd1-Br-Pd2 bond), it in fact adopts a
geometry with C1 symmetry, such that the coordination
coordination planes of the two Ni atoms are planar (rms
deviation: 0.06 Å (C1,C2,Ni1,Br,P1); 0.04 Å (C13,C15,-
Ni2,Br,P2)), and they make an angle of 119° to one
(20) (a) Uso´n, R.; Fornie´s, J.; Toma´s, M.; Menjo´n, B.; Welch, A. J.
Organometallics 1988, 7, 1318. (b) Martin, R.; Keller, H. J.; Mu¨ller,
B. Z. Naturforsch. B.: Chem. Sci. 1985, 40, 57.

3912 Organometallics, Vol. 24, No. 16, 2005
Alberti et al.
Tl2CO3 with HOTf. Microanalyses were performed by the local
Mikroanalytisches Labor Kolbe. EI mass spectra were recorded
at 70 eV; ESIpos mass spectra refer to 35Cl, 58Ni, 79Br, and
plane of Pd2 and the plane Pd2,Br,Pd1 are approxi-
mately coplanar; that is, Pd1 lies approximately in the
coordination plane of Pd2, and the coordination plane
of Pd1 lies approximately perpendicular (92.83(6)°) to
it. As a result, the coordination planes of the two Pd
atoms are almost perpendicular to one another at
bromine. The bonding of the M-X-M core of the Pd-
bromide 11b thus appears distinctly different from that
of the Ni-bromide 6c and the Pd/Pt-chlorides A-D.
The mean Pd-Br bond length of 2.547(1) Å in 11b is
only slightly longer than that in known Pd-allyl com-
plexes with terminal Pd-Br bonds (2.51 Å),21 despite
the bridging position of the bromine atom. This may be
due predominantly to the partial positive charge at the
Pd centers, which should strengthen the Pd-Br bonds
and lead to shortening, whereas possible pπ-dπ bonding
should affect both Pd-Br bonds with terminal and with
bridging Br atoms. The mean lengths of the Pd-P bonds
at 2.408(1) Å in the cation of 11b are substantially
longer than for the related neutral (π-allyl)Pd(PR3)Br
complexes (2.25-2.33 Å).21a,c
1
106Pd. Solution H NMR spectra were measured at 300 MHz,
13C NMR spectra at 75.5 MHz (both relative to TMS), and 31
P
NMR spectra at 121.5 MHz (relative to external 85% aqueous
H3PO4) on Bruker AMX-300 and DPX-300 instruments.
(η3-C3H5)Ni(PiPr3)Cl. A yellow-brown solution of {(η3-
C3H5)Ni(µ-Cl)}2 (406 mg, 3.00 mmol Ni) and PiPr3 (480 mg,
3.00 mmol) in 20 mL of diethyl ether was stirred at 0 °C for a
few minutes. Cooling the mixture from -60 to -78 °C afforded
large yellow-brown crystals, which were freed from the mother
liquor by cannulation, washed with some cold pentane (-78
°C), and dried under vacuum (-20 °C): yield 680 mg (77%).
For NMR data, see Table S1. C12H26ClNiP (295.5).
(η3-C3H5)Ni(PiPr3)Br.27 A deep red solution of {(η3-C3H5)-
Ni(µ-Br)}2 (1.80 g, 10.0 mmol Ni) in 50 mL of diethyl ether
was stirred with PiPr3 (1.60 g, 10.0 mmol) at 0 °C. The solution
was cooled below -40 °C to give small yellow-brown crystals,
which were separated as described above: yield 2.28 g (67%).
EI-MS (55 °C): m/e (%) 338 ([M]+, 15), 201 ([iPr3PC3H5]+, 100).
ESIpos-MS (CH2Cl2): m/e (%) 597 ([2M - Br]+, 100). For NMR
data, see Table 1. C12H26BrNiP (339.9).
(η3-C3H5)Ni(PiPr3)OTf.16a A solution of (η3-C3H5)Ni(PiPr3)-
Cl (296 mg, 1.00 mmol) or (η3-C3H5)Ni(PiPr3)Br (340 mg, 1.00
mmol) in 10 mL of diethyl ether was stirred with solid TlOTf
(354 mg, 1.00 mmol) at 0 °C for 30 min. After removal of the
precipitated TlX by filtration the solution was cooled below
-60 °C to give brown crystals: yield 225 mg (55%). EI-MS
(80 °C): m/e (%) 408 ([M]+, 5), 367 ([M - C3H5]+, 5), 325
([(iPr2PH)Ni(OTf)]+, 10). ESIpos-MS (CH2Cl2): m/e (%) 667
([2M - OTf]+, 15), 259 ([M - OTf]+, 80). For NMR data, see
Table S1. Anal. Calcd for C13H26F3NiO3PS (409.1). C, 38.17;
H, 6.41; F, 13.93; Ni, 14.35; O, 11.73; P, 7.57; S, 7.84. Found:
C, 38.06; H, 6.34; F, 14.11; Ni, 14.42; P, 7.51; S, 7.74. The
isolated product is unstable at ambient temperature.
(η3-C3H5)Ni(PtBu3)Cl. {(η3-C3H5)Ni(µ-Cl)}2 (406 mg, 3.00
mmol Ni) was reacted with PtBu3 (606 mg, 3.00 mmol) in 30
mL of diethyl ether at -30 °C. Cooling below -60 °C afforded
brown crystals: yield 530 mg (52%). EI-MS and ESIpos-MS:
the compound decomposed. For NMR data, see Table S1. The
complex appears unstable in solution and as a solid above -30
°C, forming a green solid. C15H32ClNiP (337.5).
Conclusions
The reactions described here shed light on the broadly
held opinion that the reaction of (η3-allyl)M(PR3)X
complexes (M ) Ni, Pd; X ) halide) with AgY or TlY
reagents of noncoordinating anions Y generates coor-
dinatively unsaturated complexes [(η3-allyl)M(PR3)]Y.
We show that under the conditions of such experiments
dinuclear ionic complexes [{(η3-C3H5)M(PR3)}2(µ-X)]Y
are formed, and these contain a strong central M-µ-
X-M linkage that is not cleaved by additional Ag/TlY
in the absence of donor ligands.
Experimental Part
All manipulations were carried out under argon using
Schlenk-type glassware. Solvents were dried prior to use by
distillation from NaAlEt4 or P4O10. {(η3-C3H5)Ni(µ-X)}2 and
22
(η3-C3H5)Ni(PtBu3)Br. Synthesis was as described above,
but reacting {(η3-C3H5)Ni(µ-Br)}2 (1.80 g, 10.0 mmol Ni) with
PtBu3 (2.02 g, 10.0 mmol) in 50 mL of diethyl ether at -30 °C
to give dark red crystals: yield 2.29 g (60%). EI-MS and
ESIpos-MS: the compound decomposed. For NMR data, see
Table 1. The complex appears unstable in solution above -30
°C, forming a green solid. C15H32BrNiP (382.0).
{(η3-C3H5)Pd(µ-X)}2 (X ) Cl, Br, I), TlB{3,5-C6H3(CF3)2}4,24
23
TlB(C6F5)4,25 LiAl{OC(CF3)3}4,11 and PtBu3 were prepared
26
according to the literature. AgPF6, AgOTf, and TlPF6 were
obtained from Aldrich, and TlOTf was prepared by reacting
(21) (a) Ku¨hn, A.; Burschka, C.; Werner, H. Organometallics 1982,
1, 496. (b) Khan, B. T.; Mohan, K. M.; Khan, S. R. A.; Venkatasubra-
manian, K.; Satyanarayana, T. Polyhedron 1996, 15, 63. (c) Nelson,
S. G.; Hilfiker, M. A. Org. Lett. 1999, 1, 1379.
(η3-C3H5)Pd(PiPr3)Cl.6b For the synthesis and properties,
see ref 16b. NMR data of the CH2Cl2 solution are included in
Table 1. C12H26ClPPd (343.2).
(22) Wilke, G.; Bogdanovic, B. Angew. Chem. 1961, 73, 756. Wilke,
G. Angew. Chem. 1963, 75, 10; Angew. Chem., Int. Ed. Engl. 1963, 2,
105. Wilke, G.; Bogdanovic, B.; Hardt, P.; Heimbach, P.; Keim, W.;
Kro¨ner, M.; Oberkirch, W.; Tanaka, K.; Steinru¨cke, E.; Walter, D.;
Zimmermann, H. Angew. Chem. 1966, 78, 157; Angew. Chem., Int. Ed.
Engl. 1966, 5, 151. Bo¨nnemann, H.; Bogdanovic, B.; Wilke, G. Angew.
Chem. 1967, 77, 817; Angew. Chem., Int. Ed. Engl. 1967, 6, 804. Jolly,
P. W.; Wilke, G. In The Organic Chemistry of Nickel; Academic Press:
New York, 1974; Vol. 1, p 345. Wilke, G. (Studiengesellschaft Kohle
m. b. H.), Ger. Patent 1,194,417, 1965. Wilke, G. (Studiengesellschaft
Kohle m. b. H.), U.S. Patent 3,468,921, 1969.
(23) (a) Smidt, J.; Hafner, W. Angew. Chem. 1959, 71, 284. Hu¨ttel,
R.; Kratzer, J. Angew. Chem. 1959, 71, 456. Moiseev, I. I.; Fedor-
ovskaya, E. A.; Syrkin, Y. K. Zh. Neorg. Khim. 1959, 4, 2641. (b)
Fischer, E. O.; Bu¨rger, G. Z. Naturforsch. B 1961, 16, 702. (c) Shaw,
B. L.; Sheppard, N. Chem. Ind. 1961, 517. (d) Dent, W. T.; Long, R.;
Wilkinson, A. J. J. Chem. Soc. 1964, 1585. (e) Gubin, S. P.; Rubezhov,
A. Z.; Winch, B. L.; Nesmeyanov, A. N. Tetrahedron Lett. 1964, 39,
2881. (f) Tatsuno, Y.; Yoshida, T.; Otsuka, S. Inorg. Synth. 1979, 19,
220.
(η3-C3H5)Pd(PiPr3)Br. Synthesis was as described above,
but reacting a yellow solution of {(η3-C3H5)Pd(µ-Br)}2 (2.27 g,
10.0 mmol Pd) with PiPr3 (1.60 g, 10.0 mmol) in 15 mL of THF
at ambient temperature. Cooling to -60 °C gave pale yellow
crystals, which were isolated as described and dried under
vacuum (20 °C): yield 2.91 g (75%). EI-MS (85 °C): m/e (%)
386 ([M]+, 15), 345 ([M - C3H5]+, 5), 306 ([M - HBr]+, 10),
265 ([M - C3H5 - HBr]+, 20). ESIpos-MS (CH2Cl2): m/e (%)
693 ([2M - Br]+, 100), 307 ([M - Br]+, 100). For NMR data,
see Table 1. C12H26BrPPd (387.6).
(η3-C3H5)Pd(PiPr3)OTf. For the synthesis from (η3-C3H5)-
Pd(PiPr3)Cl and AgOTf and for the NMR properties of the THF
solution, see ref 16b. NMR data of the CH2Cl2 solution are
included in Table S1. C13H26F3O3PPdS (456.8). Clean synthesis
of the complex seems impossible from (η3-C3H5)Pd(PiPr3)Br at
ambient temperature, and reaction with TlOTf at lower
(24) Hughes, R. P.; Lindner, D. C.; Rheingold, A. L.; Yap, G. P. A.
Inorg. Chem. 1997, 36, 1726.
(25) Alberti, D.; Po¨rschke, K.-R. Organometallics 2004, 23, 1459.
(26) Fild, M.; Stelzer, O.; Schmutzler, R. Inorg. Synth. 1973, 14, 4.
(27) Wilke, G. Ger. Patent 1 793 788, 1977.

Dinuclear Complexes of Ni and Pd
Organometallics, Vol. 24, No. 16, 2005 3913
temperature (-30 °C) affords dinuclear 10a. ESIpos-MS (CH2-
Cl2): m/e (%) 764 ([2M - OTf]+, 40), 307 ([M - OTf]+, 100).
(η3-C3H5)Pd(PtBu3)Cl.28 A yellow solution of {(η3-C3H5)Pd-
(µ-Cl)}2 (1.83 g, 10.0 mmol Pd) and PtBu3 (2.02 g, 10.0 mmol)
in 15 mL of THF was stirred (20 °C). Cooling to -60 °C gave
yellow crystals, which were isolated and dried under vacuum
(20 °C): yield 3.39 g (88%). EI-MS: the compound decomposed.
ESIpos-MS (CH2Cl2): m/e (%) 733 ([2M - Cl]+, 15), 349 ([M -
Cl]+, 100). For NMR data, see Table 1. C15H32ClPPd (385.3).
(η3-C3H5)Pd(PtBu3)Br. The synthesis of this complex has
to be carried out at low temperature to avoid the formation of
[tBu3PC3H5]+[(η3-C3H5)PdBr2]- as a brown solid and noniso-
lated [Pd(PtBu3)]. A solution of {(η3-C3H5)Pd(µ-Br)}2 (2.27 g,
10.0 mmol Pd) in 10 mL of CH2Cl2 was reacted with PtBu3
(2.02 g, 10.0 mmol) at -30 °C. After evaporation of the solvent
the residue was dissolved in 10 mL of THF. Cooling to -60 °C
gave yellow crystals: yield 3.70 g (86%). EI-MS: the compound
decomposed. ESIpos-MS (CH2Cl2): m/e (%) 777 ([2M - Br]+,
10), 349 ([M - Br]+, 100). For NMR data, see Table 1. C15H32-
BrPdP (429.7). The complex needs to be stored at -30 °C.
(η3-C3H5)Pd(PtBu3)OTf. A solution of (η3-C3H5)Pd(PtBu3)-
Cl (385 mg, 1.00 mmol) in 20 mL of CH2Cl2 was stirred with
solid AgOTf (257 mg, 1.00 mmol) at -30 to 0 °C for 1 h. After
removal of the precipitated AgCl by filtration (0 °C) the
solution was concentrated under vacuum to half the volume
and an equal amount of diethyl ether was added. Cooling the
solution to -78 °C afforded yellow crystals: yield 390 mg
(78%). EI-MS (125 °C): m/e (%) 349 ([M - OTf]+, 1). ESIpos-
MS (CH2Cl2): m/e (%) 349 ([M - OTf]+, 100). For NMR data,
see Table S1. C16H32F3O3PPdS (498.9). The compound dissolves
only poorly in diethyl ether.
was added dropwise, preventing the separation of an oily
phase. Cooling the solution to -78 °C gave well-shaped brown
crystals, which were isolated as described above: yield 890
mg (57%). (The product was soluble in diethyl ether but did
not crystallize from it. Addition of pentane caused the separa-
tion of an oily product phase.) ESIpos-MS (CH2Cl2): m/e 597
([{(C3H5)Ni(PiPr3)}2(µ-Br)]+). ESIneg-MS (CH2Cl2): m/e 967
([C16AlF36O4]-, 100). For NMR data, see Table S2. C24H52-
BrNi2P2‚C16AlF36O4 (1567.0).
X-ray Crystal Structure Analysis of 6c. Crystal data:
[C24H52BrNi2P2][C16AlF36O4], from dichloromethane/pentane,
Mr ) 1567.07, crystal size 0.05 × 0.13 × 0.15 mm; a ) 15.0314-
(3) Å, b ) 17.5337(2) Å, c ) 22.1486(4) Å, V ) 5837.4(2) Å3, T
) 100 K, orthorhombic, space group P212121 (No. 19), Z ) 4,
dcalcd ) 1.783 g cm-3, F(000) ) 3128, Nonius KappaCCD
diffractometer, λ(Mo KR) ) 0.71073 Å, µ ) 1.55 mm-1, 79 757
measured and 18 529 independent reflections (Rint ) 0.069),
15 253 with I > 2σ(I), θmax ) 30.98°, Tmin ) 0.831, Tmax ) 0.932,
direct methods (SHELXS-97) and least-squares refinement
2
(SHELXL-97) on Fo , both programs from G. Sheldrick,
University of Go¨ttingen, 1997; 795 parameters. The meso
atoms of the η3-allyl groups attached to Pd are disordered over
two positions (70:30), H atoms riding, Chebyshev weights, R1
) 0.0427 (I > 2σ(I)), wR2 ) 0.0814 (all data), Flack parameter
) -0.008(5), ∆Fmax/min ) 0.951/-0.745 e Å-3 (0.73/0.70 Å from
Br).
[{(η3-C3H5)Ni(PtBu3)}2(µ-Br)][B(C6F5)4] (7a). A deep red
solution of (η3-C3H5)Ni(PtBu3)Br (1.91 g, 5.00 mmol) in 15 mL
of CH2Cl2 was stirred with solid TlB(C6F5)4 (2.21 g, 2.50 mmol)
at -30 °C for 1 h. The light yellow precipitate of TlBr was
removed by filtration. The solution was cooled to -78 °C to
give red crystals, which were isolated as described above: yield
3.20 g (94%). For NMR data, see Table S2. C30H64BrNi2P2‚C24-
BF20 (1363.1).
[{(η3-C3H5)Ni(PiPr3)}2(µ-Br)][B(C6F5)4] (6a). A brown
solution of (η3-C3H5)Ni(PiPr3)Br (340 mg, 1.00 mmol) in 15 mL
of diethyl ether was stirred with solid TlB(C6F5)4 (442 mg, 0.50
mmol) at -30 °C for 1 h. After removal of the precipitated TlBr
the solution was concentrated to a volume of about 7 mL and
about 3 mL of pentane was added. Cooling the solution to -78
°C afforded orange crystals, which were freed from the mother
liquor by cannulation, washed with a small volume of cold
pentane (-78 °C), and dried under vacuum (-30 °C): yield
130 mg (20%). (Full evaporation of the solvent leaves an oil,
and the addition of larger amounts of pentane to an ethereal
solution causes also the separation of an oil. These difficulties
explain the low yield of crystalline product.) ESIpos-MS (CH2-
Cl2): m/e 597 ([{(C3H5)Ni(PiPr3)}2(µ-Br)]+, 10). ESIneg-MS
(CH2Cl2): m/e 679 ([C24BF20]-, 100). For NMR data, see Tables
1 and S2. C24H52BrNi2P2‚C24BF20 (1278.95). The complex is
very soluble in the usual solvents.
[{(η3-C3H5)Ni(PtBu3)}2(µ-Br)][B{3,5-C6H3(CF3)2}4] (7b).
A solution of (η3-C3H5)Ni(PtBu3)Br (1.91 g, 5.00 mmol) in 15
mL of CH2Cl2 was stirred with solid TlB{3,5-C6H3(CF3)2}4 (2.67
g, 2.50 mmol) at -30 °C for 1 h. After removal of the TlBr an
equal amount of pentane was added and the solution was
cooled to -78 °C to give deep red crystals, which were isolated
as described above: yield 3.33 g (86%). For NMR data, see
Tables 1 and S2. C30H64BrNi2P2‚C32H12BF24 (1547.3).
[{(η3-C3H5)Pd(PiPr3)}2(µ-Cl)][PF6] (8a). A yellow solution
of (η3-C3H5)Pd(PiPr3)Cl (1.71 g, 5.00 mmol) in 15 mL of CH2-
Cl2 was stirred with solid TlPF6 (0.87 g, 2.50 mmol) at -30 °C
for 1 h. The light yellow precipitate of TlCl was removed by
filtration. The solution was cooled to -78 °C to give a light
yellow precipitate, which was isolated as described above:
yield 1.45 g (73%). ESIpos-MS (CH2Cl2): m/e 649 ([{(C3H5)Pd-
(PiPr3)}2(µ-Cl)]+), 307 ([(C3H5)Pd(PiPr3)]+). For NMR data, see
Table S2. Anal. Calcd for C24H52ClP2Pd2‚F6P (795.9): C, 36.22;
H, 6.59; Cl, 4.45; P, 11.68; Pd, 26.74. Found: C, 36.31; H, 6.48;
Cl, 4.45; P, 11.61; Pd, 26.60.
[{(η3-C3H5)Ni(PiPr3)}2(µ-Br)][B{3,5-C6H3(CF3)2}4] (6b). A
solution of (η3-C3H5)Ni(PiPr3)Br (680 mg, 2.00 mmol) in 10 mL
of CH2Cl2 was stirred with solid TlB{3,5-C6H3(CF3)2}4 (1.067
g, 1.00 mmol) at -30 °C for 1 h. The light yellow precipitate
of TlBr was removed by filtration. After evaporation of the
solvent under vacuum the residue was dissolved in 5 mL of
diethyl ether. Cooling the solution to -78 °C gave a brown
precipitate, which was isolated as described above: yield 1.16
g (79%). ESIpos-MS (CH2Cl2): m/e 597 ([{(C3H5)Ni(PiPr3)}2-
(µ-Br)]+, 100). ESIneg-MS (CH2Cl2): m/e 863 ([C32H12BF24]-,
100). For NMR data, see Table S2. Anal. Calcd for C24H52-
BrNi2P2‚C32H12BF24 (1463.1): C, 45.97; H, 4.41; B, 0.74; Br,
5.46; F, 31.16; Ni, 8.02; P, 4.23. Found: C, 45.25; H, 4.06; Ni,
7.87; P, 4.25.
[{(η3-C3H5)Pd(PiPr3)}2(µ-Cl)][B(C6F5)4] (8b). A solution
of (η3-C3H5)Pd(PiPr3)Cl (1.71 g, 5.00 mmol) in 15 mL of CH2-
Cl2 was stirred with solid TlB(C6F5)4 (2.21 g, 2.50 mmol) at
-30 °C for 1 h. The light yellow precipitate of TlCl was
removed by filtration. The solution was cooled to -78 °C to
give a yellow precipitate, which was isolated as described
above: yield 1.73 g (52%). ESIpos-MS (CH2Cl2): m/e 649
([{(C3H5)Pd(PiPr3)}2(µ-Cl)]+), 307 ([(C3H5)Pd(PiPr3)]+). For NMR
data, see Tables 1 and S2. C24H52ClP2Pd2‚C24BF20 (1330.0).
[{(η3-C3H5)Pd(PiPr3)}2(µ-Cl)][B{3,5-C6H3(CF3)2}4] (8c). A
solution of (η3-C3H5)Pd(PiPr3)Cl (1.71 g, 5.00 mmol) in 15 mL
of CH2Cl2 was stirred with solid TlB{3,5-C6H3(CF3)2}4 (2.67 g,
2.50 mmol) at -30 °C for 1 h. After removal of the TlCl the
solution was concentrated in a vacuum to a volume of 5 mL.
Cooling the solution below -78 °C afforded a light yellow
precipitate, which was isolated as described above: yield 3.37
g (89%). ESIpos-MS (CH2Cl2): m/e 649 ([{(C3H5)Pd(PiPr3)}2-
(µ-Cl)]+), 307 ([(C3H5)Pd(PiPr3)]+). For NMR data, see Table
[{(η3-C3H5)Ni(PiPr3)}2(µ-Br)][Al{OC(CF3)3}4] (6c). A so-
lution of (η3-C3H5)Ni(PiPr3)Br (680 mg, 2.00 mmol) in 10 mL
of CH2Cl2 was stirred with solid LiAl{OC(CF3)3}4 (974 mg, 1.00
mmol) at -30 °C for 1 h. The off-white precipitate of LiBr was
removed by filtration. The solution was concentrated to a
volume of about 1 mL (full evaporation of the solvent leaves
an oily residue), and a small amount of pentane (about 2 mL)
(28) Carturan, G.; Strukul, G. J. Organomet. Chem. 1978, 157, 475.

3914 Organometallics, Vol. 24, No. 16, 2005
Alberti et al.
S2. Anal. Calcd for C24H52ClP2Pd2‚C32H12BF24 (1514.1): C,
44.42; H, 4.26; B, 0.71; Cl, 2.34; P, 4.09; Pd, 14.06. Found: C,
43.85; H, 4.48; B, 0.92; Cl, 2.20; P, 3.89; Pd, 13.39.
diethyl ether at ambient temperature. The resulting yellow-
greenish solution was cooled to -78 °C to give off-white
microcrystals: yield 310 mg (70%). ESIpos-MS (CH2Cl2): m/e
693 ([{(C3H5)Pd(PiPr3)}2(µ-Br)]+, 100), 307 ([(C3H5)Pd(PiPr3)]+,
50). For NMR data, see Table S2. Anal. Calcd for C24H52BrP2-
Pd2‚CF3O3S‚C2H4O0.5 (880.5): C, 36.83; H, 6.41; Br, 9.07; F,
6.47; O, 6.36; P, 7.04; Pd, 24.17; S, 3.64. Found: Br, 9.25; P,
7.31; Pd, 24.17.
[{(η3-C3H5)Pd(PiPr3)}2(µ-Cl)][Al{OC(CF3)3}4] (8d). A so-
lution of (η3-C3H5)Pd(PiPr3)Cl (1.71 g, 5.00 mmol) in 15 mL of
CH2Cl2 was stirred with solid LiAl{OC(CF3)3}4 (2.44 g, 2.50
mmol) at -30 °C for 1 h. The off-white precipitate of LiCl was
removed by filtration. The solution was cooled to -78 °C to
give a beige precipitate, which was isolated as described
above: yield 1.03 g (29%). ESIpos-MS (CH2Cl2): m/e 649
([{(C3H5)Pd(PiPr3)}2(µ-Cl)]+). For NMR data, see Table S2.
C24H52ClP2Pd2‚C16AlF36O4 (1618.0).
[{(η3-C3H5)Pd(PiPr3)}2(µ-Br)][B(C6F5)4] (10b). A yellow
solution of (η3-C3H5)Pd(PiPr3)Br (775 mg, 2.00 mmol) in 15 mL
of CH2Cl2 was stirred with solid TlB(C6F5)4 (883 mg, 1.00
mmol) at -30 °C for 1 h. The light yellow precipitate of TlBr
was removed by filtration, and the solvent was completely
evaporated under vacuum to leave an off-white analytically
pure fibrous solid: yield 1230 mg (89%). ESIpos-MS (CH2-
Cl2): m/e 693 ([{(C3H5)Pd(PiPr3)}2(µ-Br)]+, 50), 307 ([(C3H5)Pd-
(PiPr3)]+, 100). For NMR data, see Tables 1 and S2. The
product dissolves very well in THF and diethyl ether, but not
in pentane and could not be crystallized from its solutions.
Anal. Calcd for C24H52BrP2Pd2‚C24BF20 (1374.4): C, 41.95; H,
3.81; B, 0.79; Br, 5.81; F, 27.65; P, 4.51; Pd, 15.49. Found: C,
41.92; H, 3.74; Br, 5.85; P, 4.44; Pd, 15.31.
[{(η3-C3H5)Pd(PtBu3)}2(µ-Cl)][PF6] (9a). A yellow solution
of (η3-C3H5)Pd(PtBu3)Cl (1.93 g, 5.00 mmol) in 15 mL of CH2-
Cl2 was stirred with solid TlPF6 (0.87 g, 2.50 mmol) at -30 °C
for 1 h. The light yellow precipitate of TlCl was removed by
filtration. CH2Cl2 was evaporated under vacuum to leave a
yellow oil, which was dissolved again in 2 mL of THF. After
addition of 8 mL of diethyl ether yellow microcrystals formed
very slowly at -78 °C, which were isolated as described
above: yield 1.61 g (73%). ESIpos-MS (CH2Cl2): m/e 733
([{(C3H5)Pd(PtBu3)}2(µ-Cl)]+), 349 ([(C3H5)Pd(PtBu3)]+). For
NMR data, see Table S2. Anal. Calcd for C30H64ClP2Pd2‚F6P
(880.0): C, 40.94; H, 7.33; Cl, 4.03; P, 10.56; Pd, 24.19.
Found: C, 40.50; H, 6.71; Cl, 4.06; P, 10.77; Pd, 24.69.
[{(η3-C3H5)Pd(PtBu3)}2(µ-Cl)][B(C6F5)4] (9b). A solution
of (η3-C3H5)Pd(PtBu3)Cl (1.93 g, 5.00 mmol) in 15 mL of CH2-
Cl2 was stirred with solid TlB(C6F5)4 (2.21 g, 2.50 mmol) at
-30 °C for 1 h. The light yellow precipitate of TlCl was
removed by filtration. The solution was cooled to -78 °C to
give yellow knots, which were isolated as described above:
yield 1.66 g (47%). ESIpos-MS (CH2Cl2): m/e 733 ([{(C3H5)Pd-
(PtBu3)}2(µ-Cl)]+), 349 ([(C3H5)Pd(PtBu3)]+). For NMR data, see
Tables 1 and S2. Anal. Calcd for C30H64ClP2Pd2‚C24BF20
(1414.1): C, 45.87; H, 4.56; P, 4.38; Pd, 15.05. Found: C, 45.50;
H, 4.46; P, 4.19; Pd, 14.42.
[{(η3-C3H5)Pd(PiPr3)}2(µ-Br)][B{3,5-C6H3(CF3)2}4] (10c).
An orange solution of (η3-C3H5)Pd(PiPr3)Br (1.94 g, 5.00 mmol)
in 15 mL of CH2Cl2 was stirred with solid TlB{3,5-C6H3(CF3)2}4
(2.67 g, 2.50 mmol) at -30 °C for 1 h. The light yellow
precipitate of TlBr was removed by filtration. The solution was
cooled below -78 °C to give an orange-yellow precipitate,
which was freed from the mother liquor by cannulation,
washed with a small volume of cold pentane (-78 °C), and
dried under vacuum (-30 °C): yield 0.90 g (23%). For NMR
data, see Table S2. C24H52BrP2Pd2‚C32H12BF24 (1558.6). Al-
though the compound formed only a powder, it was NMR
spectroscopically pure.
[{(η3-C3H5)Pd(PiPr3)}2(µ-Br)][Al{OC(CF3)3}4] (10d). An
orange solution of (η3-C3H5)Pd(PiPr3)Br (1.94 g, 5.00 mmol) in
15 mL of CH2Cl2 was stirred with solid LiAl{OC(CF3)3}4 (2.44
g, 2.50 mmol) at -30 °C for 1 h. The off-white precipitate of
LiBr was removed by filtration, and the solution was concen-
trated in a vacuum to half the volume. Cooling the solution to
-78 °C gave an orange precipitate, which was isolated as
described above: yield 1.95 g (47%). For NMR data, see Table
S2. Anal. Calcd for C24H52BrP2Pd2‚C16AlF36O4 (1662.5): C,
28.90; H, 3.15; Al, 1.62; Br, 4.81; F, 41.14; O, 3.85; P, 3.73;
Pd, 12.80. Found: C, 29.12; H, 3.35; Al, 1.85; Br, 5.26; P, 4.10;
Pd, 13.86.
[{(η3-C3H5)Pd(PtBu3)}2(µ-Cl)][B{3,5-C6H3(CF3)2}4] (9c).
A solution of (η3-C3H5)Pd(PtBu3)Cl (1.93 g, 5.00 mmol) in 15
mL of CH2Cl2 was stirred with solid TlB{3,5-C6H3(CF3)2}4 (2.67
g, 2.50 mmol) at -30 °C for 1 h. After removal of the TlCl an
equal volume of pentane was added. The solution was cooled
to -78 °C to give a yellow precipitate, which was isolated as
described above: yield 3.56 g (89%). ESIpos-MS (CH2Cl2): m/e
733 ([{(C3H5)Pd(PtBu3)}2(µ-Cl)]+), 349 ([(C3H5)Pd(PtBu3)]+). For
NMR data, see Table S2. Anal. Calcd for C30H64ClP2Pd2‚C32H12-
BF24 (1598.3): C, 46.59; H, 4.79; B, 0.68; Cl, 2.22; P, 3.88; Pd,
13.32. Found: C, 46.68; H, 5.22; B, 0.65; Cl, 2.17; P, 3.70; Pd,
12.68.
[{(η3-C3H5)Pd(PtBu3)}2(µ-Br)][OTf] (11a). A yellow solu-
tion of (η3-C3H5)Pd(PtBu3)Br (2.15 g, 5.00 mmol) in 15 mL of
CH2Cl2 was stirred with solid TlOTf (0.88 g, 2.50 mmol) at
-30 °C for 1 h. The light yellow precipitate of TlBr was
removed by filtration (-30 °C). Evaporation of the solvent
under vacuum went along with foaming. The residue was
redissolved in 5 mL of THF (-20 °C), and about twice the
volume of diethyl ether was added until the solution became
turbid. Cooling the solution to -78 °C gave yellow crystals,
which were freed from the mother liquor by cannulation,
washed with a small volume of cold ether (-78 °C), and dried
under vacuum (-30 °C): yield 1.65 g (71%). ESIpos-MS (CH2-
Cl2): m/e 777 ([{(C3H5)Pd(PtBu3)}2(µ-Br)]+), 349 ([(C3H5)Pd-
(PtBu3)]+). For NMR data, see Table S2. Anal. Calcd for C30H64-
BrP2Pd2‚CF3O3S (928.6): C, 40.10; H, 6.95; Br, 8.60; F, 6.14;
O, 5.17; P, 6.67; S, 3.45; Pd, 22.92. Found: C, 39.82; H, 6.75;
Br, 8.46; P, 6.59; Pd, 22.92.
[{(η3-C3H5)Pd(PtBu3)}2(µ-Cl)][Al{OC(CF3)3}4] (9d). A yel-
low solution of (η3-C3H5)Pd(PtBu3)Cl (1.93 g, 5.00 mmol) in 15
mL of CH2Cl2 was stirred with solid LiAl{OC(CF3)3}4 (2.44 g,
2.50 mmol) at -30 °C for 1 h. After removal of the precipitated
LiCl an equal volume of pentane was added. Cooling the
solution to -78 °C gave a yellow precipitate, which was
isolated as described above: yield 3.23 g (76%). ESIpos-MS
(CH2Cl2): m/e 733 ([{(C3H5)Pd(PtBu3)}2(µ-Cl)]+), 349 ([(C3H5)-
Pd(PtBu3)]+). For NMR data, see Table S2. C30H64ClP2Pd2‚C16-
AlF36O4 (1702.2).
[{(η3-C3H5)Pd(PiPr3)}2(µ-Br)][OTf]‚0.5THF (10a). Route
a. A yellow solution of (η3-C3H5)Pd(PiPr3)Br (775 mg, 2.00
mmol) in 15 mL of CH2Cl2 was stirred with solid TlOTf (354
mg, 1.00 mmol) at -30 °C for 1 h. The light yellow precipitate
of TlBr was removed by filtration (-30 °C), the solvent was
evaporated, and the oily residue was dissolved in 10 mL of
THF. After addition of an equal volume of diethyl ether off-
white microcrystals separated at -60 °C. The crystals were
washed with a small volume of cold ether (-78 °C) and dried
under vacuum (20 °C): yield 725 mg (82%).
[{(η3-C3H5)Pd(PtBu3)}2(µ-Br)][B(C6F5)4] (11b). A yellow
solution of (η3-C3H5)Pd(PtBu3)Br (2.15 g, 5.00 mmol) in 15 mL
of CH2Cl2 was stirred with solid TlB(C6F5)4 (2.21 g, 2.50 mmol)
at -30 °C for 1 h. The light yellow precipitate of TlBr was
removed by filtration at -30 °C. About an equal volume of
diethyl ether was added until the solution became turbid.
Cooling to -78 °C afforded yellow cubes, which were isolated
as described above: yield 3.17 g (87%). ESIpos-MS (CH2Cl2):
Route b. The solution of (η3-C3H5)Pd(PiPr3)Br (194 mg, 0.50
mmol) in 6 mL of THF was combined with a suspension of
(η3-C3H5)Pd(PiPr3)OTf 16 (228 mg, 0.50 mmol) in 15 mL of

Dinuclear Complexes of Ni and Pd
Organometallics, Vol. 24, No. 16, 2005 3915
m/e 777 ([{(C3H5)Pd(PtBu3)}2(µ-Br)]+), 349 ([(C3H5)Pd(PtBu3)]+).
For NMR data, see Tables 1 and S2. Anal. Calcd for C30H64-
BrP2Pd2‚C24BF20 (1458.5): C, 44.47; H, 4.42; B, 0.74; Br, 5.48;
F, 26.05; P, 4.25; Pd, 14.59. Found: C, 44.65; H, 4.38; Br, 5.73;
P, 4.42; Pd, 15.42.
precipitate, which was isolated as described above: yield 2.40
g (62%). ESIpos-MS (CH2Cl2): m/e 777 ([{(C3H5)Pd(PtBu3)}2-
(µ-Br)]+), 349 ([(C3H5)Pd(PtBu3)]+). For NMR data, see Table
S2. Anal. Calcd for C30H64BrP2Pd2‚C16AlF36O4 (1746.6): C,
31.63; H, 3.69; Al, 1.54; Br, 4.57; F, 39.16; O, 3.66; P, 3.55;
Pd, 12.19. Found: C, 31.87; H, 3.50; P, 3.65; Pd, 12.48.
X-ray Crystal Structure Analysis of 11b. Crystal data:
[C30H64BrP2Pd2][BC24F20], pale yellow cubes from dichlo-
romethane, Mr ) 1458.51, crystal size 0.10 × 0.22 × 0.26 mm,
a ) 14.8137(1) Å, b ) 22.6355(1) Å, c ) 17.6457(1) Å, â )
103.9953(3)°, V ) 5741.2(1) Å3, T ) 100 K, monoclinic, space
group P21/c (No. 14), Z ) 4, dcalcd ) 1.687 g cm-3, F(000) )
2920, Nonius KappaCCD diffractometer, λ(Mo KR) ) 0.71073
Å, µ ) 1.48 mm-1, 150 322 measured and 18 299 independent
reflections (Rint ) 0.050), 15 872 with I > 2σ(I), θmax ) 31.03°,
Tmin ) 0.758, Tmax ) 0.862, direct methods (SHELXS-97) and
Reaction of (η3-C3H5)Ni(PMe3)Br with TlPF6: [(η3-
C3H5)Ni(PMe3)2][PF6] (12). A deep red solution of (η3-C3H5)-
Ni(PMe3)Br (1.28 g, 5.00 mmol) in 15 mL of CH2Cl2 was stirred
with solid TlPF6 (880 mg, 2.50 mmol) at -30 °C for 1 h. The
light yellow precipitate of TlBr was removed by filtration.
Cooling the solution to -78 °C gave an orange precipitate,
which was isolated as described above: yield 640 mg (32%
relating to Pd). ESIpos-MS (CH2Cl2): m/e 251 ([(C3H5)Ni-
(PMe3)2]+, 100). 1H NMR: δ ∼5.3 (m, 1H, Hmeso), 4.00 (m, 2H,
2
H
syn), 2.66 (m, 2H, Hanti), 1.50 (m, 18H, Me). 13C NMR: δ 116.2
least-squares refinement (SHELXl-97) on Fo , both programs
(1C, Cmeso), 67.8 (2C, Cterm), 16.6 (6C, Me). 31P NMR: δ -13.8.
from G. Sheldrick, University of Go¨ttingen, 1997; 747 param-
eters. The meso atoms of the η3-allyl groups attached to Pd
are disordered over two positions (50:50) and two C atoms of
one tri-tert-butylphosphine ligand show signs of disorder (70:
30). H atoms on major component riding, Chebyshev weights,
C9H23F6NiP3 (396.9).
Reaction of (η3-C3H5)Pd(PMe3)Cl with TlPF6: [(η3-
C3H5)Pd(PMe3)2][PF6] (13). Synthesis was as described
above, but reacting a yellow solution of (η3-C3H5)Pd(PMe3)Cl
(1.295 g, 5.00 mmol) with TlPF6 (880 mg, 2.50 mmol) to afford
a light yellow precipitate: yield 670 mg (30% relating to Pd).
ESIpos-MS (CH2Cl2): m/e 299 ([(C3H5)Pd(PMe3)2]+, 100). 1H
NMR: δ 5.51 (m, 1H, Hmeso), 4.32 (m, 2H, Hsyn), 3.12 (m, 2H,
R1 ) 0.0484 (I > 2σ(I)), wR2 ) 0.1239 (all data), ∆Fmax/min
)
3.747/-4.405 e Å-3 (0.64/0.67 Å from Pd1).
[{(η3-C3H5)Pd(PtBu3)}2(µ-Br)][B{3,5-C6H3(CF3)2}4] (11c).
A yellow solution of (η3-C3H5)Pd(PtBu3)Br (2.15 g, 5.00 mmol)
in 15 mL of CH2Cl2 was stirred with solid TlB{3,5-C6H3(CF3)2}4
(2.67 g, 2.50 mmol) at -30 °C for 1 h. The precipitated TlBr
was removed by filtration and the solution was concentrated
to half the volume. Cooling the solution to -78 °C gave orange-
yellow knots, which were isolated as described and dried under
vacuum (-30 °C): yield 2.30 g (56%). ESIpos-MS (CH2Cl2):
m/e (%) 349 ([(C3H5)Pd(PtBu3)]+, 100). For NMR data, see Table
S2. Anal. Calcd for C30H64BrP2Pd2‚C32H12BF24 (1642.8): C,
45.33; H, 4.66; B, 0.66; Br, 4.86; P, 3.77; Pd, 12.96. Found: C,
45.26; H, 4.88; B, 0.64; Br, 4.69; P, 3.61; Pd, 12.63.
H
anti), 1.59 (m, 18H, Me). 13C NMR: δ 122.8 (1C, Cmeso), 70.4
(2C, Cterm), 17.6 (6C, Me). 31P NMR: δ -18.7. C9H23F6P3Pd
(444.6).
Acknowledgment. We thank Mrs. Waltraud Ben
Mustapha for diligent technical assistance.
Supporting Information Available: Supplementary NMR
data (Tables S1 and S2) and tables of X-ray data collection
information, atom coordinates and thermal parameters, and
bond lengths and angles (Tables S3-S10 and Figures S1 and
S2), together with CIF data, for 6c and 11b. This material is
available free of charge via the Internet at http://pubs.acs.org.
[{(η3-C3H5)Pd(PtBu3)}2(µ-Br)][Al{OC(CF3)3}4] (11d). A
yellow solution of (η3-C3H5)Pd(PtBu3)Br (2.15 g, 5.00 mmol) in
15 mL of CH2Cl2 was stirred with solid LiAl{OC(CF3)3}4 (2.44
g, 2.50 mmol) at -30 °C for 1 h. The precipitated TlBr was
removed by filtration, and the solution was concentrated to
about 10 mL. Cooling the solution to -78 °C gave a yellow
OM050020F