Novel BPPFA palladium complexes. P,P to P,N rearrangements promoted by chelating κ3-N,P,P-BPPFA intermediates

Article abstract of DOI:10.1021/om010656g

The palladium complexes with BPPFA (N,N-dimethyl-1-[2,1′-bis(diphenylphosphino)-ferrocenyl]ethylamine) and the ligand 1,1′-bis(diphenylphosphino)-2-methylferrocene (BPPFMe, 1) were synthesized. The displacement of weak donor ligands from the appropriate palladium(II) precursors leads to the different derivatives of the compound. The results regarding the formation of the tetranuclear complexes have shown that a P,P to P,N coordination shift and Pd-P bond rupture are feasible processes.

Full text of DOI:10.1021/om010656g

Organometallics 2002, 21, 789-802
789
Articles
Novel BP P F A P a lla d iu m Com p lexes. P ,P to P ,N
Rea r r a n gem en ts P r om oted by Ch ela tin g K3-N,P ,P -BP P F A
In ter m ed ia tes
Blanca R. Manzano,*,†,‡ Fe´lix A. J alo´n,† Felipe Go´mez-de la Torre,†
Ana M. Lo´pez-Agenjo,† Ana M. Rodr´ıguez,§ Kurt Mereiter,|
Walter Weissensteiner,*, and Thomas Sturm
Facultad de Quı´micas, Universidad de Castilla-La Mancha, Avda. Camilo J . Cela 10,
E-13071 Ciudad Real, Spain, Escuela Te´cnica Superior de Ingenierı´a Industrial,
Universidad de Castilla La Mancha, Avda. Camilo J . Cela 3, E-13071 Ciudad Real, Spain,
Department of Chemistry, Vienna University of Technology, Getreidemarkt 9,
A-1060 Vienna, Austria, and Institut fu¨r Organische Chemie, Universita¨t Wien,
Wa¨hringer Strasse 38, A-1090 Wien, Austria
Received J uly 23, 2001
Novel palladium complexes with BPPFA (N,N-dimethyl-1-[2,1′-bis(diphenylphosphino)-
ferrocenyl]ethylamine) and the newly prepared ligand 1,1′-bis(diphenylphosphino)-2-meth-
ylferrocene (BPPFMe, 1) have been synthesized. Racemic BPPFA reacts with Pd2(dba)3‚
CHCl3 in the presence of electron-withdrawing alkenes to give palladium(0) complexes
Pd(BPPFA)(alkene), where alkene ) dimethyl fumarate (2), maleic anhydride (3). Displace-
ment of weak donor ligands from the appropriate palladium(II) precursors leads to the
derivatives [Pd(η3-2-Me-C3H4)(BPPFA)]TfO (4), Pd(C6F5)2(BPPFA) (5), Pd(C6F5)2(BPPFMe)
(6), PdMe2(BPPFA) (7), and PdClMe(BPPFA) (8). Complexes 2-4 and 8 each exist in solution
as two diastereomers that do not interconvert at room temperature on the NMR time scale.
In all mononuclear complexes BPPFA is P,P-coordinated to palladium. When PdClX(cod) (X
) Cl, Me) is reacted with (RC,SP)-BPPFA in a Pd:L ratio higher than 1:1, polynuclear species
are formed. A Pd:L ratio of 2:1 leads to the tetranuclear derivatives {cis-PdClX(µ-κ3-BPPFA)}2-
{PdX(µ-Cl)2PdX} (X ) Me (9), Cl (10)), while a ratio of 1.5:1 gives the trinuclear complexes
{cis-PdClX(µ-κ3-BPPFA)}2(trans-PdClX) (X ) Me (11), Cl (12)) along with the corresponding
tetra- and mononuclear derivatives. Mechanistic studies concerning the formation of the
tetranuclear complexes have shown that a P,P to P,N coordination shift and Pd-P bond
rupture are feasible processes. Variable-temperature 1H NMR studies have provided evidence
of Pd-N interactions in complexes 2, 5, 7, and 8 that involve an unprecedented terdentate
κ3N,P,P chelate coordination of BPPFA to palladium. The pentafluorophenyl complexes 5
and 6 each exist in solution as two conformers that are interconvertible by torsional twisting
of the Cp rings. In the case of complex 5 this interconversion process is slowed at low
temperature to such an extent that both conformers can be observed separately by NMR
spectroscopy. This phenomenon is presumably due to the Pd-N interaction. The molecular
structures of 2M and 8M (M ) major isomer) have been determined by X-ray diffraction.
Ch a r t 1
In tr od u ction
Bi- and multifunctional ferrocene derivatives have
been used successfully as ligands in homogeneous
catalysts for almost three decades.1 The enantiopure
aminophosphines PPFA2 and BPPFA (Chart 1) are
among the most widely used derivatives and are em-
ployed not only as catalyst ligands but also as starting
materials for the synthesis of other bi- and multifunc-
tional ferrocene derivatives. PPFA and BPPFA are
easily prepared in both enantiomeric forms (RC,SP and
SC,RP) as well as both diastereomeric forms (RC,RP and
SC,SP) from enantiopure (R)- or (S)-N,N-dimethyl-1-
ferrocenylethylamine.3 Substitution of the dimethyl-
amino group of aminophosphines PPFA or BPPFA with
nucleophiles allows the preparation of a diverse range
† Facultad de Qu´ımicas, Universidad de Castilla-La Mancha.
‡ E-mail: Blanca.Manzano@uclm.es.
§ Escuela Te´cnica Superior de Ingenier´ıa Industrial, Universidad
de Castilla-La Mancha.
| Vienna University of Technology.
Universita¨t Wien.
(1) Hayashi, T. In Ferrocenes: Homogeneous Catalysis, Organic
Synthesis, Material Science; Togni, A., Hayashi, T., Eds., VCH:
Weinheim, Germany, 1995; Chapter 2.
(2) Hayashi, T.; Yamamoto, K.; Kumada, M. Tetrahedron Lett. 1974,
4405.
(3) Marquarding, D.; Klusacek, H.; Gokel, G.; Hoffmann, P.; Ugi, I.
J . Am. Chem. Soc. 1970, 92, 5389.
10.1021/om010656g CCC: $22.00 © 2002 American Chemical Society
Publication on Web 02/06/2002

790 Organometallics, Vol. 21, No. 5, 2002
Manzano et al.
Sch em e 1
of ligands with amino, hydroxyl, thiol, phosphino, and
other functional groups attached to the ethyl side
chain.4,5a,6 Coordination of such ferrocenyl-phosphine
ligands to transition-metal units leads to precatalysts
for a variety of homogeneous asymmetric reactions,
including, among others, cross-coupling reactions, allylic
substitutions, hydrogenation and hydrosilylation of ole-
fins and ketones, and aldol-type condensations.7-9 In
several cases BPPFA-modified catalysts work far better
than those derived from PPFA.1
In recent years we have been interested in the
coordination properties of ferrocenyl ligands and have
reported on the coordination and fluxional behavior of
PPFA Pd10 and Ru11 complexes. For instance, we
demonstrated by means of NMR spectroscopy that
Pd-N bond cleavage is a feasible process for PPFA-
Pd(0) and -Pd(II) derivatives but is of higher energy
for other ferrocenylaminophosphine complexes.10a Fur-
ther studies have been carried out to assess the influ-
ence of the metal oxidation state and the structure of
ancillary ligands on the nature of this bond rupture
process.10b
As a bidentate ligand PPFA must be P,N-coordinated
while, at least in principle, BPPFA could be P,N or P,P
coordinated. According to the reported X-ray structure
of a mononuclear palladium complex, BPPFA is selec-
tively P,P-coordinated.12 An interesting aspect of this
structure concerns the fact that the lone pair of the
noncoordinated dimethylamino nitrogen is pointing
almost directly toward the metal unit in a way that is
essentially preorganized for metal coordination. On the
basis of this structural property one could imagine a
pentacoordinated species with BPPFA as a tridentate
chelating ligand that could act as an intermediate in a
P,P T N,P coordination exchange process. With this idea
in mind, the work described in this paper is focused on
the different coordination modes of BPPFA Pd(0) and
Pd(II) complexes with olefin, allyl, chloro, methyl, and
pentafluorophenyl groups as ancillary ligands. The
possible participation of the dimethylamino group in the
coordination and fluxional behavior of BPPFA com-
plexes in solution was anticipated. We also expected
that a better knowledge of the coordination properties
of BPPFA versus PPFA would contribute to our under-
standing of the similarities and differences between
these ligands in catalytic systems.
Resu lts a n d Discu ssion
Syn th esis of th e New Der iva tives. For the sake
of comparison the new ligand BPPFMe (1) was synthe-
sized from ((dimethylamino)methyl)ferrocene (see Scheme
1 for the reaction scheme employed), which was subse-
quently transformed into Ia using the method described
by Hayashi et al.5a Treatment of Ia with acetic anhy-
dride led to the acetate Ib. Subsequent reaction of this
compound with n-BuLi gave, after hydrolysis, the cor-
responding alcohol Ic, which was then reduced with
LiAlH4 in the presence of AlCl3 to give BPPFMe (1).
Palladium(0) complexes were prepared from Pd2-
(dba)3.CHCl3, rac-BPPFA, and an electron-withdrawing
alkene, such as dimethyl fumarate (DMFU) or maleic
anhydride (MA), as shown in eq 1. Excess dba was
removed by column chromatography.
Pd2(dba)3‚CHCl3 + 2BPPFA + 2L f
2Pd(BPPFA)L + 3dba (1)
2, 3
(4) (a) Appleton, T. D.; Cullen, W. R.; Evans, S. V.; Kim, T.-J .;
Trotter, J . J . Organomet. Chem. 1985, 279, 5. (b) Sihler, R.; Werz, U.;
Brune, H.-A. J . Organomet. Chem. 1989, 368, 213. (c) Hayashi, T.;
Yamazaki, A. J . Organomet. Chem. 1991, 413, 295.
L ) DMFU (2), MA (3)
Chloride was removed from the dimer [Pd(η3-2-Me-
C3H4)Cl]2 in a coordinating solvent, and subsequent
addition of BPPFA gave the allyl complex 4 (see eq 2).
(5) (a) Hayashi, T.; Mise, T.; Fukushima, M.; Kagotani, M.; Na-
gashima, N.; Hamada, Y.; Matsumoto, A.; Kawakami, S.; Konishi, M.;
Yamamoto, K.; Kumada, M. Bull. Chem. Soc. J pn. 1980, 53, 1138. (b)
Pastor, S. D.; Togni, A. J . Am. Chem. Soc. 1989, 111, 2333. (c) Togni,
A.; Pastor, S. D. J . Org. Chem. 1990, 55, 1649. (d) Deus, N.; Hu¨bener,
G.; Herrmann, R. J . Organomet. Chem. 1990, 384, 155.
(6) (a) Gokel, G. W.; Marquarding, D.; Ugi, I. K. J . Org. Chem. 1972,
37, 3052. (b) Togni, A.; Ha¨usel, R. Synlett 1990, 633. (c) Togni, A.; Rihs,
G.; Blumer, R. E. Organometallics 1992, 11, 613. (d) Togni, A.; Breutel,
C.; Schnyder, A.; Spindler, F.; Landert, H.; Tijani, A. J . Am. Chem.
Soc. 1994, 116, 4062.
(7) Brunner, H.; Zettlmeier, W. Handbook of Enantioselective Ca-
talysis with Transition Metal Compounds; VCH: Weinheim, Germany,
1993.
(8) Sawamura, M.; Ito, Y. Chem. Rev. 1992, 92, 857.
(9) Ojima, I., Ed. Catalytic Asymmetric Synthesis; VCH: Weinheim,
Germany, 1993.
[Pd(η3-2-Me-C3H4)Cl]2 + 2AgTfO f
2 [Pd(η3-2-Me-C3H4)(S)2]TfO + AgCl 2BPPFA8
2 [Pd(η3-2-Me-C3H4)(BPPFA)]TfO
(2)
4
Complexes 5-7 were prepared by substitution of 1,5-
cyclooctadiene (cod) or tetramethylethylenediamine
(TMEDA) from the corresponding precursors (see eq 3)
with either rac-BPPFA or rac-BPPFMe.
(10) (a) Ferna´ndez-Gala´n, R.; J alo´n, F. A.; Manzano, B. R.; Rod-
r´ıguez-de la Fuente, J .; Vrahami, M.; J edlicka, B.; Weissensteiner, W.;
J ogl, G. Organometallics 1997, 16, 3758. (b) Go´mez-de la Torre, F.;
J alo´n, F. A.; Lo´pez-Agenjo, A.; Manzano, B. R.; Rodr´ıguez, A.; Sturm,
T.; Weissensteiner, W.; Mart´ınez-Ripoll, M. Organometallics 1998, 17,
4634.
PdR (Fec)
PdR2(L′) + Fec f
+ L′
(3)
2
5-7
(11) J alo´n, F. A.; Lo´pez-Agenjo, A.; Manzano, B. R.; Moreno-Lara,
M.; Rodr´ıguez, A.; Sturm, T.; Weissensteiner, W. J . Chem. Soc., Dalton
Trans. 1999, 4031.
(12) Hayashi, T.; Kumada, M.; Higuchi, T.; Hirotsu, K. J . Orga-
nomet. Chem. 1987, 334, 195.
L′ ) cod, R ) C6F5, Fec ) BPPFA, 5; L′ ) cod,
R ) C6F5, Fec ) BPPFMe, 6; L′ ) TMEDA,
R ) Me, Fec ) BPPFA, 7

Novel BPPFA Palladium Complexes
Organometallics, Vol. 21, No. 5, 2002 791
Sch em e 2
Complex 7 reacts with halogenated solvents such as
chloroform to give the corresponding chloromethyl
derivative. The substitution of the second methyl group
also takes place, but at a much slower rate. The
synthesis of complex 5 was also carried out with an
excess of the palladium precursor, but no other products
were detected in this case.
In contrast, the outcome of the reaction between
PdClMe(cod) or PdCl2(cod) and BPPFA depends strongly
on the stoichiometry. For these particular reactions
enantiomerically pure (RC,SP)-BPPFA was used. When
the reactions were carried out with a Pd:BPPFA ratio
of 1:1, the expected mononuclear complex PdClMe-
(BPPFA) (8) or the previously described derivative
PdCl2(BPPFA)12 was formed. With a Pd:BPPFA ratio
of 2:1, the tetranuclear derivatives [(PdClX)2(BPPFA)]2
(X ) Me (9), Cl (10)) were obtained (see Scheme 2 and
Characterization of the New Derivatives). The use of a
1.5:1 ratio led to a more complicated situation: besides
the corresponding mononuclear and tetranuclear de-
rivatives, new trinuclear complexes of formula {cis-
PdClX(µ-BPPFA)}2(trans-PdClX) (X ) Me (11), Cl (12))
were formed (see Scheme 2).
The same results were obtained after consecutive
additions of 1, 0.5, and 0.5 equiv of PdClX(cod) to 1 equiv
of BPPFA in an NMR tube. In the case where X ) Cl,
the addition of 0.5 equiv of PdCl2(cod) to PdCl2(BPPFA)
was monitored by 31P NMR spectroscopy at room
temperature. Although three products were initially
present (PdCl2(BPPFA), 10, and 12), an increase in the
amount of trinuclear complex 12 was observed with time
along with a concomitant decrease in the amounts of
PdCl2(BPPFA) and 10. After approximately 1 h the
equilibrium ratio (12:PdCl2(BPPFA):10 ) 3:2:1) was
reached. This observation proves that 12 can be formed
by reacting 2 equiv of PdCl2(BPPFA) with 1 equivalent
of tetranuclear 10. Addition of 2 equiv of BPPFA to 9
or 10 resulted in the formation of 8 or PdCl2(BPPFA),
respectively. The different transformations specified
above show that the mononuclear, trinuclear, and
tetranuclear derivatives are present in a reversible
equilibrium that mainly depends on the Pd:BPPFA
stoichiometry.
Ch a r a cter iza tion of th e New Der iva tives. All new
complexes were characterized by elemental analysis, IR
spectroscopy, and 1H, 19F, 31P{1H} (see Table 1), and 13C-
{1H} NMR spectroscopy. COSY, NOE, and selective 31
P
decoupling experiments were used to gain additional
structural information. In some cases FAB mass spectra
were also recorded.
All data for the BPPFMe ligand (1) are in accordance
with the structure proposed (see Table 1 and Experi-
mental Section).
1
(a ) Mon on u clea r Der iva tives. The 31P{1H} and H
NMR spectra of compounds 5-7 show only one species,
whereas the spectra for 2-4 and 8 show the presence
in solution of two isomers in different ratios. In the 31P-
{1H} NMR spectra, either two doublets or an AB system
is observed for each product or isomer. The chemical
shifts and the presence of P-P couplings are indicative
of P,P-coordination. In complexes 5 and 6 the P-P
coupling is not observed, probably due to signal broad-
ening caused by multiple coupling with the fluorine
nuclei of the pentafluorophenyl groups (W1/2 ) 70 Hz).
The absence of diastereotopic methyl signals for the
NMe2 group in their respective 1H or 13C{1H} NMR

792 Organometallics, Vol. 21, No. 5, 2002
Manzano et al.
Ta ble 1. 31P {1H} NMR Da ta for Liga n d s a n d
Com p lexes 2-12 a t Room Tem p er a tu r ea
Ch a r t 2
complex or
ligand
Mb
m
BPPFAc
BPPFAd
1d
-18.37, -23.93
-14.78, -20.57
-20.05, -24.81
15.45 (d), 14.86 (d), J PP )9.2
2d
AB system, 17.18,
17.03, J PP ) 13.6
3c
4c
21.38 (d), 20.36 (d), J PP ) 25.0 22.43 (d), 19.52 (d),
J PP ) 22.6
AB system, 25.73 (d),
25.07 (d), J PP ) 37.3
PA, 17.33 (b s); PB, 10.39 (b s)
PA, 19.05 (b s); PB, 17.26 (b s)
PA ) 20.93(d), PB ) 16.75(d),
J PP ) 20.1
PA ) 36.03 (d), PB ) 8.22 (d),
J PP ) 31.1
PA, 25.51; PB, 31.24
PA, 11.53; PB, 31.64
PA, 25.13; PB, 22.47
PA, 11.44; PB, 16.43
AB system, 26.01,
24.41, J PP ) 37.5
5d
6d
7d
8d
37.37 (d), 15.46 (d),
J PP ) 28.0
9d
10e
11d
12e
a
b
Singlets, if not indicated otherwise. δ in ppm, J in Hz. For
PA and PB see Chart 4. c In acetone-d6. In benzene-d6. e In
d
chloroform-d.
spectra and the position of the resonances are consistent
with a noncoordinated dimethylamino nitrogen. A par-
tial assignment of the phenyl protons was made, with
the ortho protons that are coupled to phosphorus being
the most easily recognized. In complexes 5 and 6 some
of these protons are also coupled to fluorine. Interest-
ingly, as in the case of (BPPFA)PdCl2, the protons of
the stereogenic center (C*H) in complexes 7 and 8
appear at high chemical shifts (5.80 (7) and 5.87 ppm
(8)), while the corresponding protons in all other com-
plexes appear in the range 3.98-4.94 ppm. This effect
is likely to be the result of comparable preferred
conformations of (BPPFA)PdCl2, 7, and 8 in solution. A
more detailed structural comparison of (BPPFA)PdCl2
and 8 is made in the discussion below.
Ch a r t 3
Considering the asymmetry of the ferrocenyl diphos-
phine ligands and the results previously obtained with
similar palladium complexes of ferrocenyl aminophos-
phine ligands,10 the isomers of complexes 2-4 and 8
were assigned as follows: (i) face isomers in the case of
complex 2 (either the Si or the Re face of the olefin is
coordinated to Pd), (ii) rotamers in the case of 3 and 4
with the endocyclic oxygen (3) or the allyl fragment (4)
oriented either endo or exo with respect to the CHMe-
NMe2 group, and (iii) geometrical isomers (8) with the
chloride or methyl groups cis to either one or the other
ferrocenyl phosphorus atom (see Chart 2).
At room temperature both isomers of complex 2 give
rise to two resonances for the alkene protons (AB system
for the minor isomer) and for the ester methyl groups
(resonance ratio 77:23). This observation rules out a
rapid alkene rotation about the Pd-alkene axis at this
temperature. The same situation applies to complex 3,
since separate signals are observed at room temperature
for the two isomers (isomer ratio 67:33). The allyl groups
of both diastereomers (isomer ratio 62:38) of complex 4
are asymmetric, with the Hsyn protons appearing as
broad pseudotriplets while the Hanti protons give rise
to doublets with higher phosphorus coupling constants.
NOE studies were performed in order to determine
the structure of each diastereomer of complexes 2 and
8. Complexes 2 and 8 were chosen, because in each case
the solid-state structure of one diastereomer had been
elucidated by an X-ray diffraction study (see below).
Hence, it was of interest to find out whether the major
diastereomers in solution (C6D6) were identical with
those found in the solid state. In the case of 2 it is
necessary to bear in mind that this complex was
prepared from racemic BPPFA. To simplify the following
discussion, we will refer to the (RC,SP)-BPPFA enanti-
omer only. The most important NOE interactions found
for the major isomer 2M (M ) major isomer) are
indicated with arrows in Chart 3.
When the dimethylamino group was irradiated, an
NOE was found with the alkene signal at 4.84 ppm. This
interaction could only arise when the alkene Re face is
coordinated to the Pd[(RC,SP)-BPPFA] fragment. In
addition, a very weak NOE with the other olefin
resonance at 5.23 ppm was observed, which might be
an indication of a certain degree of alkene rotation,
albeit slow enough not to give rise to any signal
broadening at room temperature. The structural as-
signment of the major isomer is also in agreement with
the NOE observed between the methyl group at the

Novel BPPFA Palladium Complexes
Organometallics, Vol. 21, No. 5, 2002 793
Ch a r t 4
asymmetric carbon and the resonance at 4.84 ppm. In
a similar NOE study the major diastereomer of complex
8 (8M) was found to be identical with that in the solid
state. The phenyl ortho protons were first correlated
with their respective phosphorus resonances. The cis or
trans arrangement of the Pd-Me group with respect to
the ligand phosphorus atoms was established by selec-
tive 31P decoupling. The most important NOEs concern-
ing the orientation of the methyl group are indicated
in Chart 4 and are consistent with the methyl group
being trans to the phosphorus PB.
In the cases of complexes 5 and 6 the 19F NMR spectra
indicate the presence of two distinct pentafluorophenyl
groups in a state of restricted rotation with respect to
the Pd-C bond. Thus, for both derivatives four multi-
plets are observed for the ortho fluorines and two
doublets of doublets for the para substituents. The
resonances of the m-fluorine nuclei are partially over-
lapped. 19F-19F-COSY spectra were recorded for both
complexes. In the spectrum of complex 6, two sets of
19F signals corresponding to the individual pentafluo-
rophenyl rings could be identified by analyzing the
cross-peaks between the Fpara-Fmeta and Fmeta-Fortho
nuclei. Remarkably, the 19F-19F-COSY spectrum also
shows inter-ring coupling interactions of different in-
F igu r e 1. 19F-19F-COSY of complex 6 (Fortho region). The
cross-peak marked with the arrow reflects the inter-
annular Fa1-Fb1 coupling; the smaller cross-peak corre-
sponds to an intraannular Fb1-Fb2 coupling.
coordinated to different metal centers. (ii) In both the
1H and 13C NMR spectra, two different singlets, as-
signed to the aminomethyl groups, appear at frequen-
cies higher than those of the free ligand. These diaste-
reotopic signals are indicative of P,N coordination. (iii)
Only one set of resonances is seen for each type of
ferrocenyl ligand, reflecting a certain degree of sym-
metry in the complexes.
tensity between the ortho fluorines Fa1-Fb1 and Fa2
-
Fb2 (see Figure 1). This situation indicates a preferred
conformation of the pentafluorophenyl rings in which
the strongly coupled fluoro substituents Fa1-Fb1 are in
close proximity.14 The accidental isochrony of three Fmeta
substituents in complex 5 did not allow the unambigu-
ous assignment of all fluorine resonances of the two
rings or allow evidence to be obtained for a coupling
interaction between the ortho fluorines of nonidentical
rings.
The resonances of the Pd-Me groups proved to be
very useful in elucidating the structure of the chloro-
methyl derivatives 9 and 11. For each complex two types
of Pd-Me groups are observed, implying the presence
of two different palladium centers. The values for the
H-P coupling constants (4.1-6.4 Hz) are in accordance
with a cis arrangement of the methyl groups and the
phosphorus atoms. The absence of observable J CP
coupling constants in the corresponding 13C NMR
(b) P olyn u clea r Der iva tives. As stated previously,
derivatives 11 and 12 are always obtained as one
component of a product mixture. However, the use of
enriched samples, obtained by recrystallization, allowed
a signal assignment to be made.
All polynuclear species show several common char-
acteristics in their NMR spectra (i) Two singlets in the
31P NMR spectra that are shifted to lower field with
respect to those of free BPPFA, a situation in agreement
with coordination to a Pd center. The absence of P-P
coupling indicates that the two phosphorus atoms are
1
spectra also supports this view. In the H NMR spec-
trum of complex 11, the methyl groups give rise to a
doublet and a triplet in a 2:1 ratio. All the data for
complex 11 are consistent with the trinuclear structure
shown in Scheme 2, in which a trans-PdClMe group
connects two cis-PdClMe(µ-κ3-BPPFA) units. For the
tetranuclear complex 9, two signals in a 1:1 ratio are
observed for the methyl groups. For complex 9 we
propose a structure in which the dinuclear central unit
[MePd(µ-Cl)2PdMe] connects two terminal cis-PdClMe-
(µ-κ3-BPPFA) moieties (Scheme 2). Structures similar
to those of 9 and 11 are proposed for complexes 10 and
12. In these cases a central [PdCl2] (12) or a [ClPd(µ-
Cl)2PdCl] (10) unit with a trans geometry is present that
minimizes steric repulsions between the two terminal
units. This effect is particularly important in complex
(13) (a) Hayashi, T. Pure Appl. Chem. 1988, 60, 7. (b) Hayashi, T.;
Yamamoto, A.; Hagihara, T.; Ito, Y. Tetrahedron Lett. 1986, 27, 191.
(c) Hayashi, T.; Yamamoto, A.; Ito, Y.; Nishioka, E.; Miura, H.; Yanagi,
K. J . Am. Chem. Soc. 1989, 111, 6301.
(14) Albe´niz, A. C.; Casado, A. L.; Espinet, P. Organometallics 1997,
16, 5416.

794 Organometallics, Vol. 21, No. 5, 2002
Manzano et al.
Sch em e 3
1
12. Several of the H and 13C NMR resonances, as well
as the 31P NMR resonances, in the tetranuclear deriva-
tives 9 and 10 are broad at room temperature. This
could indicate a fluxional process that is likely to involve
the central unit.
by 31P{1H} NMR spectroscopy. A Pd:BPPFA ratio of 2:1
is appropriate for the formation of tetranuclear species.
However, considering that two different palladium
fragments are involved, it is feasible, from a statistical
point of view, that eight other tetranuclear species can
be formed in addition to complexes 9 and 10. After the
first few minutes of the reaction only two pairs of
singlets (in a ratio of 8:2) were observed in the region
of the P-coordinated BPPFA phosphorus nuclei (major,
31.00 and 12.05 ppm; minor, 31.38 and 27.38 ppm).
These signals do not correspond to those of complexes
9 and 10 (see Table 1) but are due to two new
compounds. After a reaction time of 30 min new signals
with more complicated patterns appeared and the
amount of the initial products, especially the major
component, decreased. The simplicity of the 31P NMR
pattern for both initial products is consistent with C2
symmetry. Apart from 9 and 10 only two dispositions
fit this condition, those with terminal PdClMe and
central PdCl2 fragments or the reverse situation. All
other isomers are C1-symmetrical and would be expected
to give rise to four 31P signals. Comparison of the
chemical shifts of signals for the initially formed com-
pounds with those of complexes 9, 10, and PdClX(PPFA)
(X ) Cl, Me) revealed that the major isomer must be
the complex {cis-PdCl2(µ-κ3-BPPFA)}2(MePd(µ-Cl)2PdMe)
with terminal (P,N-BPPFA)PdCl2 units, while the minor
isomer corresponds to {cis-PdClMe(µ-κ3-BPPFA)}2(ClPd-
(µ-Cl)2PdCl) with terminal (P,N-BPPFA)PdClMe units
(see Scheme 3).
For the polynuclear compounds 9-12, the 31P NMR
resonances (see Table 1) of the terminal κ2-P,N-PdClX
(X ) Cl, Me) groups were assigned by comparison with
those of the complexes PdClMe(PPFA)10b (24.09 ppm)
and PdCl2(PPFA)15 (13.73 ppm). As expected, these
chemical shifts are very similar for species with identical
terminal units, e.g. 9 and 11 or 10 and 12. The
assignment of all other phosphorus resonances was
straightforward.
A transfer of magnetization between the two ami-
nomethyl groups was observed in complex 11 at room
temperature. According to our previous studies with
similar ligands10 this interchange is due to a Pd-N bond
rupture process, which is likely to be favored by the high
trans influence of the methyl groups. Additional evi-
dence for this process is provided by a pronounced
broadening of the aminomethyl signals at 55 °C (CDCl3)
1
in the H NMR spectrum. In the case of 9 (C6D6) the
coalescence between the two aminomethyl resonances
was actually reached at 331 K, indicating a free energy
of activation of ∆Gq ) 64.9 kJ mol-1, a value similar
331
to those found for PPFA complexes.10
The FAB mass spectra of the isolated complexes 9 and
10 are in accordance with the proposed polynuclear
compositions. Although the signal corresponding to the
molecular ion was not detected, fragments with four or
three palladium atoms, such as [Pd4Cl4Me2(BPPFA)2]+
for 9 or [Pd3Cl5(BPPFA)2]+ for 10, were identified (see
Experimental Section for fragmentation details). The IR
spectra of these complexes show bands assigned to Pd-
Clterminal and Pd-Clbridge (see Experimental Section).
To obtain additional information about the mecha-
nism of formation of the polynuclear species, particu-
larly the tetranuclear complexes, we monitored the
reaction of PdCl2(BPPFA) with 1 equiv of PdClMe(cod)
It is clear that the formation of both initial products
proceeds in a highly selective manner, and this can be
understood by invoking two different kinetically favored
reaction pathways. The major isomer is likely to be the
result of a P,P to P,N coordination shift of the PdCl2
unit of PdCl2(BPPFA), coordination of a PdClMe unit
to PB, and dimerization of two identical dinuclear units
(Scheme 3, path A). The formation of the minor isomer,
on the other hand, is represented in path B. The
sequence involves coordination of the PdClMe fragment
to the noncoordinated nitrogen of the PdCl2(BPPFA)
complex, cleavage of the PdCl2-PA bond, P,N coordina-
(15) Hayashi, T.; Konishi, M.; Fukushima, M.; Mise, T.; Kagotani,
M.; Tajika, M.; Kumada, M. J . Am. Chem. Soc. 1982, 104, 180.

Novel BPPFA Palladium Complexes
Organometallics, Vol. 21, No. 5, 2002 795
tion of the PdClMe unit, and subsequent dimerization.
Both C2-symmetric initial products must be the result
of kinetic control, while all other isomers are formed at
a much slower rate, presumably through scrambling
processes. In both pathways A and B, one Pd-P bond
must be opened up for the process to proceed.
P d -N In ter a ction s in th e Mon on u clea r Der iva -
tives. To identify additional fluxional processes, includ-
ing Pd-N interactions in the mononuclear complexes,
variable-temperature NMR experiments with deriva-
tives 2, 3, and 5-8 were carried out.
1
The H NMR spectrum of complex 3 did not change
significantly, even on cooling the sample down to -80
°C. In contrast, decreasing the temperature of complex
2 led to a splitting of the signal for the aminomethyl
1
group in the H NMR spectrum, a situation consistent
with an interaction between the metal center and the
aminomethyl nitrogen. The shift difference (δν) between
the diastereotopic methyl groups in the slow exchange
regime is similar to that observed for P,N-coordinated
PPFA complexes.10,15 These signals coalesce at 203 K,
corresponding to a ∆Gq
value for the Pd-N bond
203
rupture of 38 kJ mol-1. As mentioned above, this barrier
is considerably higher in tetracoordinated κ2-N,P-PPFA
complexes.10
F igu r e 2. Variable-temperature NMR spectra of complex
5 (aminomethyl region). A and B indicate the signals
corresponding to conformers A and B (Chart 5); the asterisk
indicates a residual signal for toluene-d8.
1
When the H NMR spectrum of complex 7 (toluene-
d8) was recorded at 183 K, the aminomethyl signal was
seen to broaden significantly (W1/2 ) 100 Hz at 183 K)
but did not split into two separate signals. However,
splitting of the aminomethyl group resonance was
observed for the major isomer of the chloromethyl
complex 8 when the temperature was decreased. As in
complex 2, the most plausible explanation for this fact
is the existence of an interaction between the nitrogen
atom of the side chain and the palladium center. The
barrier associated with the exchange of the amino-
reotopic nature of the methyl groups of the major
component (A) as being caused by coordination of the
amino nitrogen to the palladium center. All three
aminomethyl signals broaden when the temperature is
increased and only one resonance is observed at tem-
peratures above 233 K, a fact consistent with the
existence of two rapidly interconverting isomers. Con-
sequently, and in contrast to the complexes described
above, a second species with a noncoordinated amino-
methyl group is observed for compound 5 at low tem-
perature. To establish the influence of the aminomethyl
group on the equilibrium between the two isomers of 5,
the bis(pentafluorophenyl)palladium complex of ligand
1, i.e., complex 6, was investigated. When the temper-
ature was lowered to 193 K, neither a second isomer
methyl signals was calculated to be ∆Gq
) 36 kJ
193
mol-1. In addition, at low temperature a splitting of the
ortho proton resonances of rings A2 and B1 (Chart 4)
was observed. This fact can be explained in terms of a
restricted rotation of these phenyl groups at low tem-
perature. No further splitting was observed in either
1
the H or 31P NMR spectra.
1
Variable-temperature H and 31P{1H} NMR studies
1
nor any other splitting of 31P or H NMR resonances of
were carried out on complex 5 over the temperature
range 193 K to room temperature. The 31P{1H} NMR
spectrum at 193 K contained four broad singlets corre-
sponding to two P,P-coordinated BPPFA complexes in
a 3:1 ratio. When the temperature was increased, these
6 was observed.
In accordance with the known X-ray structures of Pd
complexes of BPPFA,12 dppf16 (1,1′-bis(diphenylphos-
phino)ferrocene), and similar ligands,13c,17 the Cp rings
always adopt a staggered or nearly staggered conforma-
tion. Such an arrangement means that two conformers
(A and B in Chart 5) are possible for P,P-coordinated
complexes and these would be interconvertible by a
mutual twist of the Cp rings. It is generally assumed
for dppf complexes that even at low temperatures such
conformers are in a dynamic equilibrium with a very
low energy barrier.18 Hayashi et al.12 have reported that
for BPPFA derivatives conformer B is disfavored due
to steric hindrance between the alkyl side chain and one
of the phenyl groups (A2 in Chart 5). Indeed, conformer
A has been found exclusively in all known X-ray
structures of BPPFA complexes (PdCl2‚BPPFA,12 2 and
8). As can be seen from Chart 5, in the case of BPPFA
Pd(II) complexes conformer A is well-suited for an
resonances coalesced in pairs (∆Gq228 ) 45.6 and ∆Gq
253
) 44.9 kJ mol-1), leading to the expected equilibrium
of two rapidly interchanging species at room tempera-
ture. Unfortunately, severe signal overlap in the 1H
NMR spectrum at 193 K makes the aromatic and
cyclopentadienyl regions rather complex. The presence
of two species in a 3:1 ratio was, however, confirmed
from the *C-Me signals.
From the coalescence of these signals a free energy
of activation of 45.8 kJ mol-1 at 233 K was calculated,
which is in good agreement with the values deduced
from the 31P NMR spectra. The aminomethyl signals
show an interesting pattern (Figure 2): three reso-
nances in a ratio of 1.5:1.5:1 were observed, indicating
a mixture of two isomers. We interpret the diaste-

796 Organometallics, Vol. 21, No. 5, 2002
Manzano et al.
Ch a r t 5
interaction between the NMe2 nitrogen and palladium
while conformer B is not.
and 8. Such an interaction is only possible in conformer
B and constitutes indirect evidence for the presence of
this conformer in solution for the pentafluorophenyl
derivatives 5 and 6 but not for 7 and 8 (see Chart 5).
The minor isomer of 5 lacks such a Pd-N interaction,
and therefore its conformation is likely to be B. It should
be mentioned that conformer B is not unprecedented.
Such a system has been found in the solid-state struc-
ture of a palladium dichloride complex with a C2-
symmetric BPPFA related ligand (2,2′-bis(1-(dimethyl-
amino)ethyl)-1,1′-bis(diphenylphosphino)ferrocene).17 To
find further evidence to support this view, we carried
out a number of room-temperature NOE experiments
on complexes 5-8. The observed NOE correlations are
nearly identical for all complexes and are indicated in
Chart 5. Practically the whole set of NOEs is consistent
with the presence of conformer A in solution. In fact,
some NOEs, for example those observed between the
ortho Ph protons of rings A1 with H5 and A2 with H5′
(see Chart 5), are only possible in conformer A and not
in conformer B. However, an additional NOEsbetween
the ortho Ph protons of ring B2 and H5 of CpAswas
observed in complexes 5 and 6 but not in complexes 7
In summary, according to the VT-NMR and NOE
results, only the pentafluorophenyl complexes 5 and 6
exist in solution in an equilibrium of rapidly intercon-
verting conformers, with conformer A being the more
stable. In addition, in comparison to 6 the interconver-
sion barrier of the two conformers of 5 is sufficiently
high to be measured by VT-NMR and is likely to be
influenced by the Pd-N interaction in conformer A.
In conclusion, a Pd-N interaction has been found not
only in Pd(II) complexes (5, 7, 8) but also in a Pd(0)
complex (2). In all these cases, the low-temperature
chemical shifts of the 31P NMR resonances indicate that
both phosphorus atoms are coordinated, thus showing
the ability of BPPFA to act as a terdentate chelating
κ3N,P,P ligand. To the best of our knowledge, this type
of coordination for BPPFA is described here for the first
time. Although pentacoordinated palladium(II) com-
plexes19 have been described not only as being intermed-
iates19a,20 or being in equilibrium with the square-planar
species21 (in the presence of excess of ligand) but also
as isolated compounds,22 sometimes together with their
(16) (a) Yeo, J . S. L.; Li, G.; Yip, W-H.; Henderson, W.; Mak, T. C.
W.; Hor, T. S. A. J . Chem. Soc., Dalton Trans. 1999, 435. (b) Hayashi,
T.; Konishi, M.; Kobori, Y.; Kumada, M.; Higuchi, T.; Hirotsu, K. J .
Am. Chem. Soc. 1984, 106, 158. (c) Butler, I. R.; Cullen, W. R.; Kim,
T.-J .; Rettig, S. J .; Trotter, J . Organometallics 1985, 4, 972. (d) de Lima,
G. M.; Filgueiras, C. A. L.; Giotto, M. T. S.; Mascarenhas, Y. P.
Transition Met. Chem. 1995, 20, 380. (e) Chin, C. C. H.; Yeo, J . S. L.;
Loh, Z. H.; Vittal, J . J .; Henderson, W.; Hor, T. S. A. J . Chem. Soc.,
Dalton Trans. 1988, 3777. (f) Ma, J .-F.; Yamamoto, Y. Inorg. Chim.
Acta 2000, 299, 164. (g) Huang, Z.-H.; Huang, Z.-X.; Zhang, H.-H. Chin.
J . Struct. Chem. (J iegou Huaxue) 1997, 16, 324. (h) Driver, M. S.;
Hartwig, J . F. J . Am. Chem. Soc. 1997, 119, 8232. (i) Butler, I. R.;
Hobson, L. J .; Coles, S. J .; Hursthouse, M. B.; Malik K. M. A. J .
Organomet. Chem. 1997, 540, 27. (j) Hartwig, J . F. Angew. Chem., Int.
Ed. 1998, 37, 2090. (k) Li, G.; Li, S.; Tan, A. L.; Yip, W.-H.; Mak, C.
W.; Hor, T. S. A. J . Chem. Soc., Dalton Trans. 1996, 4315. (l) Hashmi,
A. S. K.; Naumann, F.; Probst, R.; Bats, J . W. Angew. Chem., Int. Ed.
1997, 36, 104. (m) Housecroft, C. E.; Owen, S. M.; Raithby, P. R.;
Shaykh, B. A. M. Organometallics 1990, 9, 1617. (n) Chi-Chang, L.;
Yong-Shou, L.; Li, L. Chin. J . Struct. Chem. (J iegou Huaxue) 1991,
10, 201. (o) Baumann, T. F.; Sibert, J . W.; Olmstead, M. M.; Barrett,
A. G. M.; Hoffman, B. M. J . Am. Chem. Soc. 1994, 116, 2639. (p)
Baumann, T. F.; Nasir, M. S.; Sibert, J . W.; White, A. J . P.; Olmstead,
M. M.; Williams, D. J .; Barrett, A. G. M.; Hoffman, B. M. J . Am. Chem.
Soc. 1996, 118, 10479. (q) Brown, J . M.; Perez-Torrente, J . J .; Alcock,
N. W.; Clase, H. J . Organometallics 1995, 14, 207.
(19) (a) Comprehensive Organometallic Chemistry; Wilkinson, G.,
Stone, F. G. A., Abel, E., Eds.; Pergamon Press: Oxford, U.K., 1982;
Vol. 6, p 235. (b) Poe, A. J .; Vaughan, D. H. Inorg. Chim. Acta 1967,
1, 255. (c) Coe, J . S.; Hussain, M. D.; Malik, A. A. Inorg. Chim. Acta
1968, 2, 65. (d) Verstuyft, A. W.; Cary, L. W.; Nelson, J . H. Inorg. Chem.
1975, 14, 1495; 1976, 15, 3161. (e) Verstuyft, A. W.; Nelson, J . H. Inorg.
Chem. 1975, 14, 1501. (f) Meakin, P.; J esson, J . P. J . Am. Chem. Soc.
1974, 96, 5751, 5760. (g) Meakin, P.; English, A. D.; J esson, J . P. J .
Am. Chem. Soc. 1976, 98, 414, 422. (h) Collier, J . W.; Mann, F. G.;
Watson, D. G.; Watson, H. R. J . Chem. Soc. 1964, 1803.
(20) (a) Stockland, R. A.; Anderson, G. K., J r. Organometallics 1998,
17, 4694. (b) Frankcombe, K. E.; Cavell, K. J .; Yates, B. F.; Knott, R.
B. Organometallics 1997, 16, 3199. (c) Ashimori, A.; Bachand, B.;
Calter, M. A.; Govek, S. P.; Overman, L. E.; Poon, D. J . J . Am. Chem.
Soc. 1998, 120, 6488. (d) Kapteijn, G. M.; Dervisi, A.; Grove, D. M.;
Kooijman, H.; Lakin, M. T.; Spek, A. L.; van Koten, G. J . Am. Chem.
Soc. 1995, 117, 10939.
(21) (a) De Felice, V.; Cucciolito, M. E.; De Renzi, A.; Ruffo, F.;
Tesauro, D. J . J . Organomet. Chem. 1995, 493, 1. (b) Fanizzi, F. P.;
Intini, F. P.; Maresca, L.; Natile, G.; Canfranchi, M.; Tiripicchio, A. J .
Chem. Soc., Dalton Trans. 1991, 1007. (c) De Felice, V.; Albano, V. G.;
Castellari, C.; Cucciolito, M. E.; De Renzi, A. J . Organomet. Chem.
1991, 403, 269.
(17) Hayashi, T.; Yamamoto, A.; Hojo, M.; Kishi, K.; Ito, Y.;
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(18) Gan, K.-S., Hor, T. S. A. In ref 1, pp 41-43.

Novel BPPFA Palladium Complexes
Organometallics, Vol. 21, No. 5, 2002 797
Ta ble 2. Cr ysta l Da ta a n d Str u ctu r e Refin em en t
double-bond length C3-C4 was found to be 1.407(4) Å,
which is similar to that in the corresponding PPFA
derivative.10a The square-planar unit shows a slight
pyramidal distortion, with the plane C3-Pd-C4 tilted
with respect to the plane P1-Pd-P2 away from the
dimethylamino group with normal distances of 0.273 Å
for C4 and 0.202 Å for C3. The two phosphorus atoms
lie almost in the plane of their respective Cp rings, with
deviations of 0.045 Å for P1 and 0.008 Å for P2. As
depicted in Figure 3 (right projection), the Cp rings
adopt a synclinal staggered conformation with P1 situ-
ated between P2 and the 1-(dimethylamino)ethyl sub-
stituent. A rather large bite angle (P1-Pd1-P2) of
105.68(3)° was found.
Complex 8 crystallizes from benzene in the form of
the stable solvate 8‚1/2C6H6, which adopts the monoclinic
space group P21. The asymmetric unit contains two
independent Pd complexes with very similar dimensions
and shapes. The molecular structure of one independent
complex molecule is shown in Figure 4.
The configuration of both molecules is identical with
that found for the major isomer in solution, with the
methyl group (attached to palladium, C11) positioned
cis with respect to P1. The Cp rings adopt a staggered
conformation with the bond C31-P2 bisecting the bond
C21-C22 (Figure 4, right projection). All other struc-
tural features of BPPFA are as expected. In contrast to
2, the P1-Pd-P2 bond angle is only slightly opened up
to 98.0°.
for 2 a n d 8‚1/2C6H6
2
8‚1/2C6H6
empirical formula
C44H45FeN-
O4P2Pd
C42H43ClFe-
NP2Pd
fw
876.00
821.42
temp, K
293(2)
297(2)
wavelength, Å
0.710 70
0.710 73
cryst syst, space group
monoclinic, P21/c
monoclinic, P21
unit cell dimens
a, Å
b, Å
c, Å
10.696(3)
18.060(6)
20.672(8)
94.60(2)
3980(2)
18.258(4)
10.126(3)
22.275(5)
113.61(2)
3773.5(16)
4; 1.446
â, deg
V, Å3
Z; calcd density, Mg/m3 4; 1.462
abs coeff, mm-1
max and min
transmissn
0.940
1.000 and 0.715
1.047
1.00 and 0.90
F(000)
1800
1684
crystal size, mm
θ range for data
collecn, deg
0.2 × 0.2 × 0.4
0.07 × 0.11 × 0.68
2.22-27.99
2.00-30.00
limiting indices
0 e h e 14
0 e k e 23
-27 e l e 27
-25 e h e 25
-14 e k e 14
-31 e l e 31
no. of rflns collected/
unique
9562/9562 (R(int) ) 54 537/21 293
0.0000)
(R(int) ) 0.037,
R(σ) ) 0.053)
no. of data/restraints/
params
9562/0/478
21 293/1/865
goodness of fit on F2
final R indices
(I > 2σ(I))
0.906
0.971
R1 ) 0.0316,
wR2 ) 0.0532
R1 ) 0.0653,
wR2 ) 0.0642
0.482 and -0.531
R1 ) 0.0353,
wR2 ) 0.0672
R1 ) 0.0584,
wR2 ) 0.0742
0.322 and -0.337
R indices (all data)
largest diff peak
and hole, e Å-3
Str u ctu r a l Com p a r ison of 2, 8‚1/2C6H6, a n d P d Cl2-
(BP P F A).12 All three complexes adopt a similar overall
conformation (conformation A, Chart 5) with staggered
Cp rings. While the molecular structures of PdCl2-
(BPPFA) and 8‚1/2C6H6 are almost superimposable,
significant differences are seen in 2. In particular, as
compared to PdCl2(BPPFA), the phenyl rings of the
diphenylphosphino groups are rotated in order to mini-
mize steric interactions with the DMFU unit. Interest-
ingly, the position of the dimethylaminoethyl side chain
is almost identical in all three complexes. Hence, the
chemical shift differences seen for the *CH protons of 2
as compared to PdCl2(BPPFA) and 8‚1/2C6H6 are likely
to be caused by conformational changes of the diphen-
ylphosphino phenyl groups rather than by changes in
the (dimethylamino)ethyl unit.
solid-state structure,23 the coordination number 5 is not
common in palladium(II) chemistry.
X-r a y Str u ctu r es of Com p lexes 2 a n d 8. Crystal-
lographic data of 2 and 8 are given in Table 2.
Complex 2 crystallizes in the monoclinic space group
P21/c with four molecules per unit cell. An ORTEP plot
of the molecular structure of 2 is shown in Figure 3.
In agreement with the data obtained on the complex
in solution, the alkene Re face is coordinated to a
[(RC,SP)-BPPFA]Pd unit. The structural features of
BPPFA are as expected, with average Car-Car bond
distances of 1.422(4) Å and the two Cp rings slightly
tilted with respect to each other by 2.7(1)°. The alkene
(22) (a) Derenzi, A.; Orabona, I.; Ruffo, F. Inorg. Chim. Acta 1997,
258, 105. (b) Ru¨lke, R. E., Ernsting, J . M.; Elsevier, C. J .; Spek, A. L.;
van Leeuwen, P. W. N. M.; Vrieze, K. Inorg. Chem. 1993, 32, 5769.
(23) (a) Albano, V. G.; Castellari, C.; Cucciolito, M. E.; Panunzi, A.;
Vitagliano, A. Organometallics 1990, 9, 1269. (b) Burger, P.; Baumeis-
ter, J . M. J . Organomet. Chem. 1999, 575, 214. (c) Hinamoto, M.; Ooi,
S.; Kuroya, H. J . Chem. Soc., Chem. Commun. 1972, 356. (d)
Wieghardt, K.; Schoffmann, E.; Nuber, B.; Weiss, J . Inorg. Chem. 1986,
25, 4877. (e) Chak, B.; McAuley, A.; Whitcombe, T. W. Can. J . Chem.
1994, 72, 1525. (f) Vilar, R.; Mingos, D. M. P.; White, A. J . P.; Williams,
D. J . J . Chem. Soc., Chem. Commun. 1999, 229. (g) Constable, E. C.;
Elder, S. M.; Healy, J .; Ward, M. D.; Tocher, D. A. J . Am. Chem. Soc.
1990, 112, 4590. (h) Sakai, T.; Taira, Z.; Yamazaki, S.; Ama, T.
Polyhedron 1989, 8, 1989. (i) Hahn, C.; Vitagliano, A.; Giordano, F.;
Taube, R. Organometallics 1998, 17, 2060. (j) Blake, A. J .; Champness,
N. R.; Li, W.-S.; Schroder, M.; Bruce, D. W. Acta Crystallogr., Sect. C:
Cryst. Struct. Commun. 1998, 54, 349. (k) Wasielewski, K.; Mattes, R.
Z. Anorg. Allg. Chem. 1993, 619, 158. (l) Blake, A. J .; Holder, A. J .;
Roberts, Y. V.; Schro¨der, M. J . Chem. Soc., Chem. Commun. 1993, 260.
(m) Blake, A. J .; Roberts, Y. V.; Schro¨der, M. J . Chem. Soc., Dalton
Trans. 1996, 1885. (n) Blake, A. J .; Lippolis, V.; Parson, S.; Schro¨der,
M. J . Chem. Soc., Chem. Commun. 1996, 2207. (o) Sato, M.; Suzuki,
K.; Asano, H.; Sekino, M.; Kawata, Y.; Habata, Y.; Akabori, S. J .
Organomet. Chem. 1994, 470, 263. (p) Nikol, H.; Bu¨rgi, H.-B.; Hard-
castle, K. I.; Gray, H. B. Inorg. Chem. 1995, 34, 6319. (q) Vila, J . M.;
Pereira, M. T.; Ortigueira, J . M.; Ferna´ndez, J . J .; Ferna´ndez, A.;
Lo´pez-Torres, M.; Adams, H. Organometallics 1999, 18, 5484.
Con clu sion s
BPPFA reacts with Pd(0) or Pd(II) fragments to give
mononuclear P,P- but not P,N-coordinated complexes.
With proper fragments (Pd(alkene), Pd(CH3)Cl, and Pd-
(2-Me-C3H4)+), diastereomers are formed with a certain
degree of selectivity but in neither Pd(0) or Pd(II)
complexes was an isomer interconversion observed at
room temperature on the NMR time scale.
Depending on the Pd:BPPFA ratio, tri- or tetranuclear
complexes containing PdClX (X ) Cl, Me) fragments and
µ-κ3N,P,P-BPPFA ligands are formed. This implies that
catalytic reactions carried out “in situ” using “PdIIClX”
precursors and BPPFA must be performed with careful
control of the Pd:BPPFA ratio in order to prevent a
serious perturbation of regio- and enantioselectivity by
polynuclear species with trans PdClX units. In a mecha-
nistic study a crossover reaction between PdCl2(BPPFA)
and PdClMe(cod) complexes was carried out, and in the

798 Organometallics, Vol. 21, No. 5, 2002
Manzano et al.
F igu r e 3. Molecular structure of Pd(BPPFA)(DMFU) (2) in the crystalline state showing 20% thermal ellipsoids (hydrogen
atoms omitted, benzene rings in right view omitted). Selected bond lengths and angles (Å, deg): Pd(1)-P(1) ) 2.3404(9),
Pd(1)-P(2) ) 2.3426(10), Pd(1)-C(3) ) 2.131(3), Pd(1)-C(4) ) 2.131(3), <Fe(1)-C> ) 2.036(3), P(1)-C(11) ) 1.808(3),
P(2)-C(21) ) 1.811(3), C(3)-C(4) ) 1.407(4); P(1)-Pd(1)-P(2) ) 105.68(3), P(1)-Pd(1)-C(3) ) 107.6(1), P(1)-Pd(1)-
C(4) ) 146.2(1), P(2)-Pd(1)-C(3) ) 146.2(1), P(2)-Pd(1)-C(4) ) 107.3(1), C(3)-Pd(1)-C(4) ) 39.0(1).
F igu r e 4. Molecular structure of PdClMe(BPPFA) (8.1/2C6H6) in the crystalline state showing one of the two independent
but geometrically similar complexes with 20% thermal ellipsoids (hydrogen atoms omitted, benzene rings in right view
omitted). Selected bond lengths and angles (Å, deg): Pd-P(1) ) 2.2631(9), Pd-P(2) ) 2.4276(9), Pd-Cl ) 2.3713(9), Pd-
C(11) ) 2.089(3), <Fe-C> ) 2.040(3), P(1)-C(21) ) 1.816(3), P(2)-C(31) ) 1.826(3); P(1)-Pd-P(2) ) 97.99(3), P(1)-
Pd-Cl ) 173.62(3), P(1)-Pd-C(11) ) 87.6(1), P(2)-Pd-Cl ) 88.06(3), P(2)-Pd-C(11) ) 174.3(1), Cl-Pd-C(11) ) 86.3(1).
initial state only the two feasible C2-symmetric tetra-
nuclear products were formed. This fact implies that the
BPPFA ligand can shift from a P,P to a P,N coordination
involving a Pd-P bond rupture process.
Coordination of the NMe2 group not only to Pd(II) but
also to Pd(0) has been identified in mononuclear P,P-
BPPFA-Pd complexes at low temperature. Conse-
quently, an unprecedented chelating κ3P,P,N-BPPFA
coordination is present in solution in a dynamic equi-
librium with the κ2P,P-BPPFA form. An equilibrium
was found in the pentafluorophenyl derivatives 5 and
6 between two conformers that are interconvertible by
a torsional twist of the Cp rings. Only in the case of
complex 5 could this interconversion process be slowed,
presumably due to the palladium-nitrogen interaction.
In summary, we have demonstrated that in mono-
nuclear P,P-BPPFA Pd(II) and Pd(0) complexes the
dimethylamino nitrogen can interact with the metal
center. This interaction can not only slow conforma-
tional interchanges but is also thought to facilitate
structural rearrangements such as P,P to P,N changes
in the BPPFA coordination mode.

Novel BPPFA Palladium Complexes
Organometallics, Vol. 21, No. 5, 2002 799
(d ) Syn th esis of 2-Meth yl-1,1′-bis(d ip h en ylp h osp h in o)-
fer r ocen e (1). To 844.3 mg (22.24 mmol) of LiAlH4 in 20 mL
of dry dimethoxyethane is added 298.4 mg (2.238 mmol) of
AlCl3. After the mixture is stirred for 2 h at room temperature,
1.090 g (1.865 mmol) of Ic in 5 mL of dry DME is added
dropwise. The reaction mixture is stirred for 15 h at 90 °C.
Water (50 mL) is carefully added at 0 °C, the organic phase is
separated, and the aqueous phase is extracted with diethyl
ether (3 × 30 mL). The combined organic phases are washed
with brine and dried over anhydrous Na2SO4. After filtration,
the solvent is removed under reduced pressure and the product
is purified by chromatography on alumina: eluent, 4/1 petro-
leum ether/ethyl acetate; yield, 594 mg (56%). Anal. Calcd for
C35H30FeP2: C, 73.96; H, 5.32. Found: C, 73.13; H, 4.96. 1H
NMR (300 MHz, benzene-d6): δ 6.90-7.90 (m, 20H, Ph), 4.28
Exp er im en ta l Section
Gen er a l Com m en ts. All manipulations were carried out
under an atmosphere of dry oxygen-free nitrogen using
standard Schlenk techniques. Solvents were distilled from the
appropriate drying agents and degassed before use. Elemental
analyses were performed with a Thermo Quest FlashEA 1112
microanalyzer. IR spectra were recorded as KBr pellets or
Nujol mulls on a Perkin-Elmer PE 883 IR spectrometer. FAB
mass spectra were recorded with a VG BIOTECH Quattro
spectrometer using 3-NBA as matrix. 1H, 13C{1H}, 19F, and 31P-
{1H} NMR spectra were recorded on a Varian Unity 300 or
Bruker AC-250 spectrometer. Chemical shifts (ppm) are rela-
tive to TMS (1H, 13C NMR), CFCl3 (19F), and 85% H3PO4 (31P
NMR). The abbreviation pt refers to pseudotriplet. COSY
spectra: standard pulse sequence, acquisition time 0.214 s,
pulse width 10 µs, relaxation delay 1 s, 16 scans, 512
increments. The NOE difference spectra were recorded with
5000 Hz, acquisition time 3.27 s, pulse width 90°, relaxation
delay 4 s, and irradiation power 5-10 dB. For variable-
temperature spectra, the probe temperature ((1 K) was
controlled by a standard unit calibrated with a methanol
reference. Free energies of activation were calculated24 from
the coalescence temperature (Tc) and the frequency difference
between the coalescing signals (extrapolated at the coalescence
(m, 2H, Cp), 4.20 (m, 1H, Cp), 4.14 (m, 1H, Cp), 4.07 (t, J HH
2.4 Hz, 1H, Cp), 3.52 (m, 1H, Cp), 3.38 (m, 1H, Cp), 1.93 (s,
Me). 13C{1H} NMR (75 MHz, benzene-d6): δ 135.8 (d, J CP
)
)
21.0 Hz, Cortho Ph), 134.6 (d, J CP ) 8.8 Hz, Cmeta Ph), 134.2 (d,
J CP ) 8.5 Hz, Cmeta Ph), 133.0 (d, J CP ) 18.1 Hz, Cortho Ph),
129.6 (s, Cpara Ph), 90.7 (d, J CP ) 23.2 Hz, Cp), 77.5 (d, J CP
)
8 Hz, Cp), 75.9 (s, Cp), 75.0 (d, J CP ) 13.8 Hz, Cp), 74.0 (d, J CP
) 13.0 Hz, Cp), 73.8 (s, Cp), 72.2 (s, Cp), 71.0 (s, Cp), 14.2 (d,
J CP ) 10.3 Hz, Me).
Syn th esis of P d (BP P F A)(DMF U) (2). A mixture of BP-
PFA (80.0 mg, 0.128 mmol), DMFU (27.4 mg, 0.190 mmol),
and Pd2(dba)3‚CHCl3 (76.7 mg, 0.064 mmol) in toluene (15 mL)
is stirred for 3.5 h. After the volume of toluene is reduced to
1 mL, the reaction mixture is separated by chromatography
on silica. Toluene elutes unreacted dba and THF complex 2.
THF is removed in vacuo, and the remaining residue is washed
with hexane. After it is dried in vacuo, complex 2 is obtained
as a brown solid. Yield: 75.1 mg (67%). Ratio of isomers in
benzene: 2M:2m ) 77:23. Crystals suitable for X-ray diffrac-
tion were obtained by slow diffusion of diethyl ether vapor over
a toluene solution of 2. Anal. Calcd for C44H45FeNO4P2Pd: C,
60.32; H, 5.18; N, 1.60. Found: C, 59.84; H, 5.33; N, 1.51. IR
(cm-1, KBr): 1685 (vs, ν(CdO)). 1H NMR (300 MHz, benzene-
d6): 2M Re, δ 8.2-6.9 (m, 20H, Ph), assigned ortho protons
8.11 (m, 2H, Phortho), 8.04 (m, 2H, Phortho), 7.68 (m, 2H, Phortho),
4.92 (q, J HH ) 6.6 Hz, 1H, *CHCH3), 5.23 (ddd, J HH ) 10.0
Hz, J HP,trans ) 8.3 Hz, J HP,cis ) 3.6 Hz, 1H, CHd), 4.84 (m, 1H,
CHd), 4.39 (s, 1H, Cp), 3.98 (s, 1H, CpA), 3.96 (s, 1H, Cp), 3.80
(m, 2H, Cp), 3.74 (s, 1H, Cp), 3.65 (m, 1H, Cp), 3.24 (s, 3H,
CO2CH3), 2.96 (s, 3H, CO2CH3), 1.81 (s, 6H, N(CH3)2), 0.62 (d,
3H, *CHCH3); 2m Si, δ 8.2-6.8 (m, 20H, Ph), assigned ortho
protons 8.11 (m, 2H, Phortho), 7.63 (m, 2H, Phortho), 4.93, 4.86
(AB, J HH ) 10.1 Hz, 2H, CHdCH), 4.25 (q, J HH ) 6.3 Hz, 1H,
*CHCH3), 4.32 (s, 1H, Cp), 4.07 (s, 1H, Cp), 4.01 (s, 1H, Cp),
3.98 (s, 1H, Cp), 3.80 (s, 2H, Cp), 3.74 (s, 1H, Cp), 3.06 (s, 3H,
CO2CH3), 3.01 (s, 3H CO2CH3), 1.88 (s, 6H, N(CH3)2), 0.56 (d,
3H, *CHCH3). 13C{1H} NMR (75 MHz, chloroform-d): 2M, δ
135.6 (d, J CP ) 16.6 Hz, Cortho Ph), 135.5 (d, J CP ) 16.6 Hz,
q
temperature) with the formula ∆Gc ) aT[9.972 + log(T/δν)]
(a ) 1.914 × 10-2). The estimated error in the calculated free
energies of activation is (1.0-1.1 kJ mol-1. Pd2(dba)3‚CHCl3,25
[Pd(η3-2Me-C3H4)Cl]2,26 PdClMe(COD),27 Pd(C6F5)2(COD),28
PdMe2(TMEDA),29 and BPPFA5a were prepared according to
literature methods. PdCl2(cod)30 was prepared by displacing
benzonitrile from PdCl2(PhCN)2.
Syn th esis of BP P F Me. For the reaction sequence see
Scheme 1.
(a ) Syn th esis of 2-((Dim eth yla m in o)m eth yl)-1,1′-bis-
(d ip h en ylp h osp h in o)fer r ocen e (Ia ). This compound was
prepared according to a procedure reported by Hayashi et al.5a
(b ) Syn t h esis of 2-(Acet oxym et h yl)-1,1′-b is(d ip h en -
ylp h osp h in o)fer r ocen e (Ib). A solution of 3.67 g (6 mmol)
of Ia in 40 mL of acetic anhydride is heated at 100 °C for 2 h.
After the volume of the reaction mixture is reduced under low
pressure to 5 mL, the product is purified by chromatography
on silica: eluent, 3/1 hexane/ethyl acetate; yield, 2.146 g (57%).
1H NMR (250 MHz, CDCl3): δ 7.50-7.05 (m, 20H, Ph), 4.90
(AB, J ) 13 Hz, 2H, CH2), 4.50 (s, 1H, Cp), 4.42 (s, 1H, Cp),
4.23-4.15 (m, 3H, Cp), 3.76 (s, 1H, Cp), 3.59 (s, 1H, Cp), 1.58
(s, 3H, CH3CO2).
(c) Syn t h esis of 2-(H yd r oxym et h yl)-1,1′-b is(d ip h en -
ylp h osp h in o)fer r ocen e (Ic). To a solution of 1.945 g (3.1
mmol) of Ib in 20 mL of diethyl ether is added at 0 °C 4.65
mL (7.45 mmol) of n-BuLi. The reaction mixture is stirred for
2 h at room temperature and then hydrolyzed with water (20
mL). The aqueous phase is extracted with diethyl ether (3 ×
25 mL), and the combined organic phases are washed with
water and dried over Na2SO4. After removal of solvent under
reduced pressure the crude product is purified by chromatog-
raphy on alumina: eluent, ethyl acetate; yield, 1.793 g (99%).
1H NMR (250 MHz, CDCl3): δ 7.45-7.00 (m, 20H, Ph), 4.45
(s, 1H, Cp), 4.41-4.25 (m, 3H, Cp + CH2), 4.20-4.05 (m, 3H,
Cp), 3.79 (s, 1H, Cp), 3.56 (s, 1H, Cp).
Cortho Ph), 133.2 (d, J CP ) 14.1 Hz, Cortho Ph), 133.2 (d, J CP
)
14.6 Hz, Cortho Ph), 128.2 (d, J CP ) 9.6 Hz, Cmeta Ph), 128.1 (d,
J CP ) 9.6 Hz, Cmeta Ph), 127.7 (d, J CP ) 10.7 Hz, Cmeta Ph),
127.0 (d, J CP ) 9.6 Hz, Cmeta Ph), 130.1 (d, J CP ) 1.3 Hz, Cpara
Ph), 129.6 (d, J CP ) 1.3 Hz, Cpara Ph), 129.1 (d, J CP ) 1.3 Hz,
Cpara Ph), 129.0 (s, Cpara Ph), 97.1 (d, J CP ) 15.1 Hz, Cp), 76.1
(s, Cp), 75.6 (s, Cp), 74.6 (s, Cp), 73.5 (d, J CP ) 15 Hz, Cp),
71.7 (d, J CP ) 7.5 Hz, Cp), 70.8 (d, J CP ) 5.7 Hz, Cp), 69.1 (d,
J CP ) 1.9 Hz, Cp), 67.5 (d, J CP ) 1.9 Hz, Cp), 65.8 (s, CH-
CH3), 54.8 (dd, J CP,trans ) 24.3 Hz, J CP,cis ) 4.0 Hz, CHd), 54
(d, J CP,trans ) 25 Hz, CHd), 50.5 (s, CO2CH3), 50.3 (s, CO2CH3),
38.2 (s, N(CH3)2), 7.1 (s, CHCH3).
(24) Sandstro¨m, J . Dynamic NMR Spectroscopy; Academic Press:
London, 1982.
(25) Ukai, T.; Kawazura, H.; Ishii, Y.; Bonnet, J . J .; Ibers, J . A. J .
Organomet. Chem. 1974, 65, 253.
(26) Dent, W. T.; Wilkinson, A. J . J . Chem. Soc. 1964, 1585.
(27) Ru¨lke, R. E.; Ernsting, J . M.; Spek, A. L.; Elsevier, C. J .; van
Leeuwen, P. W. N. M.; Vrieze, K. Inorg. Chem. 1993, 32, 5769.
(28) Espinet, P.; Mart´ınez-Ilarduya, J . M.; Pe´rez-Briso, C.; Casado,
A. L.; Alonso, M. A. J . Organomet. Chem. 1998, 551, 9.
(29) de Graaf, W.; Boersma, J .; Smeets, W. J . J .; Spek, A. L.; van
Koten, G. Organometallics 1989, 8, 2907.
Syn th esis of P d (BP P F A)(MA) (3). A mixture of BPPFA
(70.0 mg, 0.112 mmol), MA (11.0 mg, 0.112 mmol), and Pd2-
(dba)3‚CHCl3 (61.0 mg, 0.051 mmol) in 15 mL of toluene is
stirred at room temperature. Within 10 min the color of the
solution changes from dark red to yellow. After 40 min the
volume of toluene is reduced to 1 mL and the reaction mixture
(30) Drew, D.; Doyle, J . R. Inorg. Synth. 1972, 13, 52.

800 Organometallics, Vol. 21, No. 5, 2002
Manzano et al.
is separated as described for 2. Crude 3 is obtained as a yellow
solid. Recrystallization from toluene/pentane yields 29.6 mg
(35%) of complex 3. Ratio of isomers in acetone: 3M/3m ) 67/
33. Anal. Calcd for C42H39FeNO3P2Pd: C, 60.80; H, 4.74; N,
1.69. Found: C, 60.23; H, 4.26; N, 1.67. IR (cm-1, KBr): 1797
and 1730 (vs, ν(CdO)). 1H NMR (300 MHz, acetone-d6): δ 7.9-
7.1 (m, Ph), assigned ortho protons 7.80 (m, 2H, Phortho, 3m ),
7.75 (m, 2H, Phortho, 3M), 7.70 (m, 2H, Phortho, 3m ),7.69 (m,
removed in vacuo, and the remaining yellow oil solidifies when
treated with hexane and ultrasound. Filtration and drying in
vacuo yields complex 5 as a yellow solid. Yield: 61.3 mg (72%).
Anal. Calcd for C50H37F10FeNP2Pd: C, 56.34; H, 3.50; N, 1.32.
Found: C, 56.07; H, 3.28; N, 1.29. IR (cm-1, KBr): 1495 (s)
and 954 (s) (C6F5). 1H NMR (300 MHz, benzene-d6): δ 8.2-
6.9 (m, 20H, Ph), assigned ortho protons 8.17 (m, 2H, Phortho,A1),
7.77 (m, 4H, Phortho,A2+B1), 7.44 (m, 2H, Phortho,B2), 3.98 (q, J HH
) 6.1 Hz, 1H, *CHCH3), 4.62 (m, 1H, CpB), 4.21 (m, 2H, CpA+B),
3.90 (m, 1H, CpA), 3.80 (m, 1H, CpB), 3.70 (s, 1H, CpA), 3.62
(s, 1H, CpA), 1.92 (s, 6H, N(CH3)2), 0.46 (d, 3H, *CHCH3). 19F
NMR (282 MHz) δ -114.71 (m, 1F, Fortho,a), -115.44 (m, 1F,
6H, Phortho, 3M), 7.50 (m, 2H, Phortho, 3m ), 7.35 (m, 2H, Phortho
,
3m ), 4.94 (qt, J HH ) 6.6 Hz, J HP ) 1.7 Hz, 1H, *CHCH3, 3M),
4.63 (qt, J HH ) 6.6 Hz, J HP ) 1.7 Hz, 1H, *CHCH3, 3m ), 4.61
(m, Cp), 4.59 (m, J HH ) 4.4 Hz, 1H, CHd, 3m ), 4.51 (m, Cp),
4.45 (m, Cp), 4.44 (m, J HH ) 4.4 Hz, 1H, CHd, 3M), 4.40 (m,
Cp), 4.36 (m, Cp), 4.36 (m, 1H, CHd, 3M), 4.29 (m, Cp), 4.12
(m, Cp), 4.06 (m, Cp), 3.95 (m, 1H, CHd, 3m ), 3.93 (m, Cp),
3.73 (m, Cp), 1.81 (s, 6H, N(CH3)2, 3M), 1.64 (s, 6H, N(CH3)2,
3m ), 1.02 (d, 3H, *CHCH3, 3M), 0.64 (d, 3H, *CHCH3, 3m ).
13C{1H} NMR (75 MHz, acetone-d6): 3M, δ 171 (b s, CO),
F
ortho), -116.52 (m, 1F, Fortho), -117.58 (m, 1F, Fortho), -162.11
(dd, J FF ) 21.4, 18.3 Hz, 1F, Fpara,a), -162. 84 (dd, J FF ) 21.3,
18.3 Hz, 1F, Fpara,b), -163.20 (m, 1F, Fmeta,a), -163.75 (m, 3F,
F
meta,a+2b). 13C{1H} NMR (75 MHz, benzene-d6): δ 148.4-128.5
(m, Ph), 146.8 (dd, J CF ) 227.2 Hz, J CP ) 21.7, 2C, CorthoC 5),
F
6
145.9 (dd, J CF ) 223.1 Hz, J CP ) 22.2 Hz, 2C, CorthoC 5), 138.3
F
6
137.4-127.6 (m, Ph), assigned ortho carbons 136.4 (d, J CP
)
(dm, J CF ) 249.3 Hz, 2C, CparaC ), 137.7 Hz, (dm, J CF ) 236
F
6
17.6 Hz, Cortho Ph), 135.5 (d, J CP ) 16.6 Hz, Cortho Ph), 134.8 (d,
J CP ) 15.6 Hz, Cortho Ph), 133.7 (d, J CP ) 13.6 Hz, Cortho Ph),
98.2 (d, J CP ) 16.1 Hz, Cp), 77.6 (d, J CP ) 5.0 Hz, Cp), 76.2 (s,
Cp), 74.5 (d, J CP ) 11.6 Hz, Cp), 72.4 (d, J CP ) 5.5 Hz, Cp),
72.3 (d, J CP ) 5.0 Hz, Cp), 70.4 (d, J CP ) 4.0 Hz, Cp), 69.8 (d,
J CP ) 4.0 Hz, Cp), 58.3 (pt, J CP ) 2.5 Hz, CHCH3), 54.1 (dd,
Hz, 4C, CmetaC ), 97.0 (d, J CP )5 8.5 Hz, Cp), 80.3 (d, J CP
)
F
6
5
14.6 Hz, Cp), 76.7 (d, J CP ) 8.6 Hz, Cp), 75.4 (dd, J CP ) 41.3,
6.5 Hz, Cp), 74.4 (d, J CP ) 9.5 Hz, Cp), 73.7 (s, Cp), 73.2 (d,
J CP ) 4.0 Hz, Cp), 72.6 (d, J CP ) 4.0 Hz, Cp), 72.1 (dd, J CP
)
40.3, 4.0 Hz, Cp), 71.4 (d, J CP ) 8.0 Hz, Cp), 55.4 (s, CHCH3),
39.0 (s, N(CH3)2), 8.0 (s, CHCH3).
J CP,trans ) 25.1 Hz, J CP,cis ) 3.0 Hz, CHd), 53.7 (dd, J CP,trans
)
Syn th esis of P d (BP P F Me)(C6F 5)2 (6). To a solution of 1
(51.8 mg, 0.091 mmol) in 15 mL of toluene is added Pd(C6F5)2-
(cod) (50.0 mg, 0.091 mmol). After it is stirred for 16 h at room
temperature, the solution is evaporated to dryness and the
remaining orange solid is washed with hexane. Orange crystals
are obtained from dichloromethane/pentane. Yield: 78.0 mg
(85%). Anal. Calcd for C47H30F10FeP2Pd: C, 55.95; H, 3.00.
Found: C, 55.48; H, 2.94. IR (cm-1, Nujol): 1498 (s), 956 (s),
25.1 Hz, J CP,cis ) 3.5 Hz, CHd), 39.4 (s, N(CH3)2), 7.8 (s, CH-
CH3); 3m , 137.4-127.6 (m, Ph), assigned ortho carbons 137.2
(d, J CP ) 16.1 Hz, Cortho Ph), 136.4 (d, J CP ) 17.6 Hz, Cortho Ph),
133.9 (d, J CP ) 14.6 Hz, Cortho Ph), 132.6 (d, J CP ) 13.1 Hz,
Cortho Ph), 77.0 (d, J CP ) 2.5 Hz, Cp), 76.4 (s, Cp), 74.9 (d, J CP
) 15.1 Hz, Cp), 73.4 (d, J CP ) 6.0 Hz, Cp), 72.6 (d, J CP ) 6.0
Hz, Cp), 70.9 (d, J CP ) 4.0 Hz, Cp), 69.4 (d, J CP ) 4.5 Hz, Cp),
57.1 (dd, J CP ) 3.0, 1.5 Hz, CHCH3), 54.9 (dd, J CP,trans ) 28.2
Hz, J CP,cis ) 3.5 Hz, CHd), 52.1 (dd, J CP,trans ) 28.7 Hz, J CP,cis
) 3.5 Hz, CHd), 38.7 (s, N(CH3)2), 7.4 (s, CHCH3).
1
and 785 (m) (C6F5). H NMR (300 MHz, benzene-d6): δ 8.2-
6.7 (m, 20H, Ph), assigned ortho protons 8.12 (m, 2H, Phortho,A2),
7.69 (m, 2H, Phortho,B1), 7.46 (m, 2H, Phortho,B2), 6.89 (m, 2H,
Phortho,A1), 4.13 (m, 1H, CpB), 4.00 (m, 1H, CpA), 3.96 (m, 1H,
CpA), 3.91 (m, 1H, CpB), 3.66 (m, 2H, CpA+B), 3.60 (m, 1H, CpB),
2.52 (s, 3H, CpCH3). 19F NMR (282 MHz): δ -113.47 (m, 1F,
Syn th esis of [P d (η3-2-Me-C3H4)(BP P F A)](CF 3SO3)‚(C-
H3)2CO (4‚(CH3)2CO). A solution of 22.0 mg (0.056 mmol) of
[(η3-2-Me-C3H4)PdCl]2 in acetone is added to a solution of light-
protected AgCF3SO3 (28.7 mg, 0.112 mmol) in methanol. After
it is stirred for 3.5 h, the reaction mixture is filtered over Celite
and BPPFA (70.0 mg, 0.112 mmol) is added. The color of the
initially yellow solution changes to orange. Stirring is contin-
ued for 2.5 h. The solvent is removed in vacuo, and the
remaining orange oil solidifies when treated with hexane and
ultrasound. After filtration and drying in vacuo complex 4 is
obtained as an orange solid. Yield: 88.0 mg (79%). Ratio of
isomers in acetone: 4M:4m ) 62;38. Anal. Calcd for C43H44F3-
FeNO3P2PdS‚C3H6O: C, 55.57; H, 5.07; N, 1.41; S, 3.28.
Found: C, 55.07; H, 4.92; N, 1.31; S, 2.93. IR (cm-1, KBr): 1268
(s), 1220 (m), 1149 (m), and 636 (m) (CF3SO3); 1028 (s), 823
F
ortho,a), -115.20 (m, 1F, Fortho,b), -115.78 (m, 1F, Fortho,a),
-117.77 (m, 1F, Fortho,b), -162.07 (pt, J FF ) 21.4 Hz, 1F, Fpara,a),
-162.70 (pt, J FF ) 19.8 Hz, 1F, Fpara,b), -163.03 (m, 1F, Fmeta,a),
-163.40 (m, 2F, Fmeta,a+b), -163.89 (m, 1F, Fmeta,b). 13C{1H}
NMR (75 MHz, benzene-d6): δ 137.0-119.6 (m, Ph), assigned
phenyl carbons 136.9 (d, J CP ) 14.6 Hz, Cortho Ph), 135.8 (b d,
J CP ) 11.0 Hz, C Ph), 133.8 (b d, J CP ) 9.4 Hz, C Ph), 130.6 (d,
J CP ) 2.9 Hz, Cpara Ph), 129.6 (d, J CP ) 2.9 Hz, Cpara Ph), 91.0
(d, J CP ) 17.4 Hz, Cp), 78.2 (s, Cp), 77.7 (m, Cp), 76.1 (d, J CP
) 4.8 Hz, Cp), 75.7 (d, J CP ) 7.7 Hz, Cp), 75.4 (d, J CP ) 2.7
Hz, Cp), 73.8 (d, J CP ) 12.6 Hz, Cp), 73.0 (d, J CP ) 8.0 Hz,
Cp), 71.3 (d, J CP ) 4.9 Hz, Cp), 70.3 (d, J CP ) 7.8 Hz, Cp), 30.1
(s, CH3-Cp).
1
(m), and 834 (2-methylallyl). H NMR (300 MHz, acetone-d6):
Syn th esis of P d Me2(BP P F A)‚1/2C6H14 (7‚1/2C6H14). To a
solution of PdMe2(TMEDA) (20.2 mg, 0.080 mmol) in 15 mL
toluene is added 50 mg (0.080 mmol) of BPPFA. After the
mixture is stirred for 20 h at room temperature, the volume
of toluene is partially reduced and hexane is added. After 16
h at 4 °C, yellow crystals of 7 are obtained. Yield: 30.3 mg
(47%). Anal. Calcd for C40H43FeNP2Pd‚1/2C6H14: C, 64.15; H,
δ 7.9-7.3 (m, Ph), assigned ortho protons 7.45 (t, J ) 7.7 Hz,
2H, Phortho, 4M), 7.31 (t, J ) 7.7 Hz, 2H, Phortho, 4m ), 4.83 (s,
1H, Cp, 4M), 4.75 (s, 1H, Cp, 4m ), 4.58-4.40 (m, Cp), 4.49 (q,
J HH ) 6.4 Hz, 1H, *CH-CH3, 4M), 4.33 (s, Cp), 4.25 (b pt, 1
H
syn), 4.16 (b s, Cp), 3.99 (s, Cp), 3.88 (b pt, 1 Hsyn), 3.84 (d,
J HP ) 7.1 Hz, 1 Hanti), 3.82 (s, Cp), 3.67 (d, J HP ) 9.8 Hz, 1
H
H
anti), 3.58 (d, J HP ) 9.3 Hz, 1 Hanti), 3.55 (d, J HP ) 7.6 Hz, 1
anti), 2.08 (s, 6H, N(CH3)2, 4m ), 2.03 (s, 6H, N(CH3)2, 4M),
6.26; N, 1.74. Found: C, 64.37; H, 6.15; N, 1.74. IR (cm-1
,
Nujol): 529 (ν(Pd-Me)).1H NMR (300 MHz, benzene-d6): δ 8.2-
6.7 (m, 20H, Ph), assigned ortho protons 8.15 (m, 2H, Phortho,B2),
8.04 (m, 2H, Phortho,A2), 7.89 (m, 2H, Phortho,B1), 7.38 (m, 2H,
Phortho,A1), 5.80 (q, J HH ) 6.8 Hz, 1H, *CHCH3), 4.11 (m, 2H,
Cp), 3.79 (t, J HH ) 2.6 Hz, 1H, Cp), 3.65 (m, 1H, Cp), 3.62 (m,
1H, Cp), 3.54 (m, 1H, Cp), 3.33 (m, 1H, Cp), 2.23 (s, 6H,
N(CH3)2), 1.14 (dd, J HP,trans ) 8.7 Hz, J HP,cis ) 5.5 Hz, 3H, Me2-
Pd), 1.13 (d, 3H, *CHCH3), 1.08 (dd, J HP,trans ) 9.3 Hz, J HP,cis
) 6.9 Hz, 3H, Me1-Pd). 13C{1H} NMR (75 MHz, benzene-d6):
δ 137.9 (d, J CP ) 16.6 Hz, Cortho Ph), 137.8 (d, J CP ) 16.1 Hz,
1.94 (s, 3H, CH3Cd, 4M), 1.25 (d, 3H, *CHCH3, 4M), 1.20 (s,
3H, CH3Cd, 4m ), 1.04 (d, J HH ) 6.6 Hz, 3H, *CHCH3, 4m ).
13C{1H} NMR (75 MHz, chloroform-d): δ 138.7-123.1 (m, Ph),
97.6 (m, Cp), 78.1 (s, Cp), 76.1 (s, Cp), 74.3 (m, Cp), 73.1 (s,
Cp), 72.9 (s, Cp), 72.4 (m, Cp), 71.0 (m, Cp), 69.5 (s, Cp), 57.6
(s, CHCH3, 4M), 56.2 (s, CHCH3, 4m ), 39.6 (s, N(CH3)2, 4M),
39.1 (s, N(CH3)2, 4m ), 29.2 (s, CH3Cd, 4M), 23.7 (s, CH3Cd,
4m ), 8.4 (s, CHCH3, 4m ), 8.3 (s, CHCH3, 4M).
Syn th esis of P d (C6F 5)2(BP P F A) (5). A solution of Pd-
(C6F5)2(cod) (43.8 mg, 0.080 mmol) and BPPFA (50.0 mg, 0.080
mmol) in 30 mL of toluene is stirred for 24 h. The solvent is
Cortho Ph), 136.0 (d, J CP ) 13.1 Hz, Cortho Ph), 135.6 (d, J CP
)

Novel BPPFA Palladium Complexes
Organometallics, Vol. 21, No. 5, 2002 801
13.6 Hz, Cortho Ph), 134.3 (d, J CP ) 9.6 Hz, Cmeta Ph), 126.8 (d,
J CP ) 9.1 Hz, Cmeta Ph), 130.3 (d, J CP ) 1.5 Hz, Cpara Ph), 129.9
(d, J CP ) 1.5 Hz, Cpara Ph), 129.6 (d, J CP ) 2.0 Hz, Cpara Ph),
99.3 (d, J CP ) 19.1 Hz, Cp), 84.4 (dd, J CP ) 31.2, 6.5 Hz, Cp),
79.1 (dd, J CP ) 30.7, 4.6 Hz, Cp), 77.5 (d, J CP ) 4.6 Hz, Cp),
75.3 (s, Cp), 73.9 (d, J CP ) 9.6 Hz, Cp), 71.2 (d, J CP ) 6.1 Hz,
Cp), 70.8 (d, J CP ) 4.0 Hz, Cp), 69.1 (d, J CP ) 3.1 Hz, Cp), 68.9
(d, J CP ) 3.1 Hz, Cp), 56.7 (d, J CP ) 2.5 Hz, CHCH3), 39.7 (s,
N(CH3)2), 13.2 (dd, J CP,trans ) 102.9 Hz, J CP,cis ) 11.3 Hz, CH3-
Pd), 8.3 (dd, J CP,trans ) 102.2 Hz, J CP,cis ) 10.1 Hz, CH3Pd), 8.0
(s, CHCH3).
{1H} NMR (75 MHz, chloroform-d): δ 135.7-128.2 (Ph),
assigned phenyl carbons 135.6 (d, J CP ) 11.5 Hz, C Ph), 133.6
(d, J CP ) 9.5 Hz, C Ph), 128.7 (d, J CP ) 11.9 Hz, Cmeta Ph),
128.3 (d, J CP ) 10.9 Hz, Cmeta Ph), 98.9 (b s, Cp), 81.6 (m, Cp),
77.5 (s, Cp), 76.0 (b s, Cp), 75.1 (b s, Cp), 73.6 (b s, Cp), 64.7
(s, CHCH3), 53.8 (s, NCH3), 51.9 (s, NCH3), 22.9 (s, CHCH3).
MS: m/z 1746 [M - Pd - 3Cl - H], 1157 [M - BPPFA - Pd
- 2Cl], 980 [M - BPPFA - 2Pd - 4Cl - H], 944 [M - BPPFA
- 2Pd - 5Cl], 766 [M - BPPFA - 3Pd - 7Cl], 804 [M -
BPPFA - 3Pd - 6Cl + H].
Syn t h esis of {cis-P d ClMe(µ-K3-BP P F A)}2(tr a n s-P d -
ClMe) (11). To a mixture of BPPFA (14 mg, 0.0224 mmol)
and PdClMe(cod) (11.8 mg, 0.0336 mmol) in an NMR tube was
added 0.5 mL of benzene-d6. Immediately afterward, sequences
Syn th esis of P d ClMe(BP P F A) (8). To a mixture of
BPPFA (14 mg, 0.022 mmol) and PdClMe(cod) (5.9 mg, 0.022
mmol) in an NMR tube was added 0.5 mL of benzene-d6. The
1H and 31P NMR spectra recorded immediately afterward
showed that only complex 8 was formed. Crystallization by
vapor diffusion of diethyl ether gave complex 8 as pale yellow
crystals. Yield: 15.4 mg (88%). Ratio of isomers in benzene
8M/8m ) 85/15. Anal. Calcd for C39H40ClFeNP2Pd: C, 59.87;
1
of H (120 scans) and 31P (240 scans) spectra were recorded
for 3 h at 20 °C until an equilibrium ratio of complexes 11, 9,
and 8 was reached. 1H NMR (300 MHz, chloroform-d): δ 8.3-
7.0 (m, 40H, Ph), assigned ortho protons 8.10 (m, 4H, Phortho),
7.96 (m, 4H, Phortho), 7.45 (m, 4H, Phortho), 7.28 (m, 4H, Phortho),
4.67 (s, 2H, Cp), 4.22 (s, 4H, Cp), 4.16 (s, 2H, Cp), 3.87 (s, 2H,
Cp), 3.59 (q, J HH ) 6.6 Hz, 2H, *CHCH3), 3.16 (s, 2H, Cp),
3.15 (s, 6H, NCH3), 3.12 (s, 2H, Cp), 2.48 (s, 6H, NCH3), 1.29
(d, 6H, *CHCH3), 0.55 (d, J HP ) 3.7, 6H, Me-Pd), -0.21 (t,
J HP ) 6.4 Hz, 3H, Me-Pd). 13C{1H} NMR (75 MHz, benzene-
d6): δ 137.9-126.9 (m, Ph), 99.3-69.6 (m, Cp), 62.5 (s,
CHCH3), 49.3 (s, N(CH3)), 45.6 (s, N(CH3)), 19.5 (s, CHCH3),
14.3 (s, MePd), 1.3 (s, MePd).
Syn th esis of {cis-P dCl2(µ-K3-BP P FA)}2(tr a n s-P dCl2) (12).
A procedure similar to that described for complex 11 was used.
An equilibrium mixture of 12 together with complexes PdCl2-
(BPPFA) and 10 was obtained. 1H NMR (300 MHz, chloroform-
d): δ 8.1-7.3 (m, 40H, Ph), assigned ortho protons 8.13 (m,
4H, Phortho), 4.70 (s, 2H, Cp), 4.68 (s, 2H, Cp), 4.25 (s, 2H, Cp),
3.95 (s, 2H, Cp), 3.90 (s, 2H, Cp), 3.50 (s, 6H, NCH3), 3.44 (s,
2H, Cp), 3.33 (s, 2H, Cp), 3.22 (q, J HH ) 6.4 Hz, 2H, *CHCH3),
2.75 (s, 6H, NCH3), 1.33 (d, 6H, *CHCH3).
Rea ction of P d Cl2(BP P F A) w ith P d ClMe(cod ). F or m a -
tion of Mixed Tetr a n u clea r Der iva tives. To a mixture of
complexes PdCl2(BPPFA) (14 mg, 0.0174 mmol) and PdClMe-
(cod) (4.6 mg, 0.0174 mmol) in an NMR tube was added 0.5
mL of chloroform-d. Sequences of 1H (120 scans) and 31P (240
scans) spectra were recorded at 20 °C for 3 h.
Tr a n sfor m a t ion s of Tet r a n u clea r t o Mon on u clea r
Der iva tives. (a ) P d Cl2(BP P F A) fr om 10. A solution of 10
in chloroform-d was prepared as described above. BPPFA (14
mg, 0.0224 mmol) was added, and both 1H and 31P NMR
spectra were recorded immediately afterward, showing the
presence of PdCl2(BPPFA) only.
1
H, 5.15; N, 1.79. Found: C, 60.04; H, 5.49; N, 1.76. H NMR
(300 MHz, toluene-d8): δ 8.7-6.6 (m, 20H, Ph), assigned ortho
protons 8.66 (m, 2H, Phortho,B1), 8.09 (m, 2H, Phortho,B2), 8.06
(m, 2H, Phortho,A1), 7.19 (m, 2H, Phortho,A2), 6.09 (q, J HH ) 6.8
Hz, 1H, *CHCH3), 4.16 (s, 1H, CpA), 4.10 (s, 1H, CpA), 3.77 (d,
J HH ) 4.2 Hz, 1H, CpA), 3.60 (s, 1H, CpB), 3.54 (s, 1H, CpB),
3.41 (s, 1H, CpB), 3.24 (s, 1H, CpB), 2.17 (s, 6H, N(CH3)2), 1.64
(dd, J HP,trans ) 8.1 Hz, J HP,cis ) 5.1 Hz, 3H, CH3Pd), 1.09 (d,
3H, *CHCH3). 13C{1H} NMR (75 MHz, benzene-d6): δ 137.4-
126.7 (Ph), 99.7 (d, J CP ) 25.5 Hz, Cp), 78.5 (d, J CP ) 6.1 Hz,
Cp), 76.1 (s, Cp), 74.6 (d, J CP ) 14.3 Hz, Cp), 72.4 (d, J CP
)
11.0 Hz, Cp), 72.2 (d, J CP ) 3.8 Hz, Cp), 71.0 (d, J CP ) 7.9 Hz,
Cp), 70.5 (d, J CP ) 3.8 Hz, Cp), 57.3 (s, CHCH3), 40.3 (s,
N(CH3)2), 19.0 (d, J CP,trans ) 97.2 Hz, CH3Pd), 8.0 (s, CHCH3).
Syn th esis of {cis-P d ClMe(µ-K3-BP P F A)}2{MeP d (µ-Cl)2-
P d Me} (9). Complex 9 was prepared as for 8, using the
following amounts: BPPFA (14 mg, 0.0224 mmol), PdClMe-
(cod) (11.8 mg, 0.0448 mmol), and benzene-d6 (0.5 mL). Yield:
19.8 mg (94%). Anal. Calcd for C80H86Cl4Fe2N2P4Pd4: C, 51.15;
H, 4.61; N, 1.49. Found: C, 51.12; H, 4.14; N, 1.52. IR (cm-1
,
Nujol mull): 316 (w), 282 (w), and 269 (w), ν(Pd-Cl). 1H NMR
(300 MHz, benzene-d6): δ 7.9-6.8 (m, 40H, Ph), assigned ortho
protons 7.91 (m, 4H, Phortho,B), 7.44 (m, 8H, Phortho,A), 7.28 (m,
4H, Phortho,B), 5.16 (b s, 2H, Cp), 4.87 (s, 2H, Cp), 4.32 (b s,
2H, Cp), 4.01 (s, 2H, Cp), 3.88 (s, 2H, Cp), 3.56 (s, 2H, Cp),
3.36 (b m, 2H, *CHCH3), 3.24 (s, 6H, NCH3), 3.13 (s, 2H, Cp),
2.62 (s, 6H, NCH3), 1.20 (d, J HP ) 4.1 Hz, 6H, Me-Pd), 1.04
(b s, 6H, Me-Pd), 1.06 (d, J HH ) 6.3 Hz, 6H, *CHCH3). 13C-
{1H} NMR (75 MHz, benzene-d6): δ 137-128 (Ph), 136.2 (d,
J CP ) 14.1 Hz, Cortho Ph), 134.2 (d, J CP ) 12.0 Hz, Cortho Ph),
133.8 (d, J CP ) 12.1 Hz, Cortho Ph), 132.8 (d, J CP ) 10.1 Hz, C
Ph), 131.3 (b s, Cpara Ph), 130.7 (b s, 4C, Cpara Ph), 129.8 (b s,
Cpara Ph), 97.8 (d, J CP ) 20.2 Hz, Cp), 78.5 (d, J CP ) 20.2 Hz,
Cp), 76.5 (d, J CP ) 7.4 Hz, Cp), 75.4 (d, J CP ) 54.9 Hz, Cp),
75.2 (d, J CP ) 7.6 Hz, Cp), 74.7 (d, J CP ) 6.5 Hz, Cp), 74.0 (d,
J CP ) 4.0 Hz, Cp), 74.0 (s, Cp), 72.5 (d, J CP ) 42.8 Hz, Cp),
62.6 (s, CHCH3), 49.3 (s, N(CH3)), 44.9 (s, N(CH3)), 18.6 (s,
CHCH3), 2.1 (s, CH3Pd), 8.9 (b s, CH3Pd). MS: m/z 1849 [M -
C2H5], 1068 [M - BPPFA - Pd - Cl - C3H8], 959 [M - BPPFA
- 2Pd - Cl - 3Me], 904 [M - BPPFA - 2Pd - 3Cl - 2Me].
Syn th esis of {cis-P dCl2(µ-K3-BP P FA)}2{ClP d(µ-Cl)2P dCl}
(10). Complex 10 was prepared as for 8 using the following
amounts: BPPFA (14 mg, 0.0224 mmol), PdCl2(cod) (12.8 mg,
0.0448 mol) and chloroform-d (0.5 mL). Yield: 22.6 mg (96%).
Anal. Calcd for C76H74Cl8Fe2N2P4Pd4: C, 46.56; H, 3.80; N,
1.43. Found: C, 45.61; H, 4.04; N, 1.36. IR (cm-1, Nujol mull):
340 (m, br), 274 (m, br) (ν(Pd-Cl)). 1H NMR (300 MHz,
chloroform-d): δ 8.2-7.3 (m, 40H, Ph), assigned ortho protons
8.22 (m, 4H, Phortho), 5.34 (s, 2H, Cp), 5.06 (s, 2H, Cp), 4.65 (s,
2H, Cp), 4.48 (s, 2H, Cp), 4.07 (s, 2H, Cp), 3.92 (s, 2H, Cp),
3.63 (s, 6H, NCH3), 3.44 (s, 2H, Cp), 2.90 (s, 6H, NCH3), 2.86
(q, J HH ) 6.4 Hz, 2H, *CHCH3), 1.54 (d, 6H, *CHCH3). 13C-
(b) 8 fr om 9. A solution of 9 in benzene-d6 was prepared
1
as described above. According to the H and 31P NMR spectra,
after the addition of BPPFA (14 mg, 0.0224 mmol), the complex
PdClMe(BPPFA) (8) is formed exclusively.
X-r a y Cr ysta l Str u ctu r e Deter m in a tion s. Com p ou n d
2. Intensity data were collected with
a Nonius MACH3
diffractometer and Mo KR radiation. The structure was solved
with direct methods and refined with SHELXL-9731 against
F2 of all reflections using anisotropic displacement parameters
for non-hydrogen atoms. Hydrogen atoms had isotropic dis-
placement parameters and were calculated riding with the
atoms to which they were bonded.
Com p ou n d 8‚1/2C6H6. Intensity data were collected on a
Bruker Smart CCD diffractometer and Mo KR radiation. Of
54 537 reflections, 21 293 were independent (θ ) 30°); Rint
)
0.037 after absorption correction on the basis of multiple
measured reflections (program SADABS32). The structure was
solved with direct methods and refined with SHELXL9731
(31) Sheldrick, G. M. SHELXL-97, Program for Crystal Structure
Refinement; University of Go¨ttingen, Go¨ttingen, Germany, 1997.
(32) Sheldrick, G. M. SADABS (version 2.03), Program for Area
Detector Absorption and Other Corrections; University of Go¨ttingen,
Go¨ttingen, Germany, 2001.

802 Organometallics, Vol. 21, No. 5, 2002
Manzano et al.
against F2 of all reflections, using anisotropic displacement
parameters for non-hydrogen atoms. Hydrogen atoms had
isotropic displacement parameters and were calculated riding
with the atoms to which they were bonded. The absolute
structure was determined; Flack parameter 0.02(1).33
za Superior e Investigaciones Cient´ıficas, Spain (Grant
No. PB98-0315) and by O¨ sterreichische Nationalbank,
Austria (project 7516).
Su p p or tin g In for m a tion Ava ila ble: Tables giving crys-
tal data for 2 and 8 as well as details of the structure
determination, non-hydrogen atomic coordinates, bond dis-
tances and angles, anisotropic thermal parameters, and
hydrogen coordinates with isotropic displacement parameters.
This material is available free of charge via the Internet at
http://pubs.acs.org.
Ack n ow led gm en t. We gratefully acknowledge the
Subdireccio´n General de Cooperacio´n Internacional for
an “Accio´n Integrada” project (HU-1999-0017) as well
as the O¨ sterreichischer Akademischer Austauschdienst
(“Accio´n Integrada”, project 18/2000). This work was
kindly supported by the Direccio´n General de Ensen˜an-
(33) Flack, H. D.; Bernardelli, G. Acta Crystallogr. 1999, A55, 908.
OM010656G