A mixed palladium(0) palladium(II) bis-diphosphaferrocene complex

Article abstract of DOI:10.1016/S0022-328X(03)00524-2

Reaction of octa-n-propyl-diphosphaferrocene (1) with [Pd(COD)Cl₂] affords a dimeric species 2 featuring two trans -[PdCl₂] fragments and two diphosphaferrocenes. Reaction of 2 with [Pd(dba)₂] yields a trimetallic complex 3. An X-ray crystal structure study reveals that 3 features a central palladium atom that does not interact with the two peripheral [PdCl₂] fragments. Complex 3 can also be formed from the reaction of two equivalents of [Pd(COD)Cl₂] with the bis-(octa-n-propyl-diphosphaferrocene)Pd(0) complex.

Full text of DOI:10.1016/S0022-328X(03)00524-2

Journal of Organometallic Chemistry 684 (2003) 189ꢂ193
/
www.elsevier.com/locate/jorganchem
A mixed palladium(0) palladium(II) bis-diphosphaferrocene complex
Mohand Melaimi, Louis Ricard, Francois Mathey *, Pascal Le Floch *
¸
Laboratoire He´teroe´le´ments et Coordination, UMR CNRS 7653, Ecole Polytechnique, 91128 Palaiseau Cedex, France
Received 18 November 2002; received in revised form 11 April 2003; accepted 9 May 2003
Dedicated to Professor Ernest Otto Fischer on the occasion of his 85th birthday
Abstract
Reaction of octa-n-propyl-diphosphaferrocene (1) with [Pd(COD)Cl2] affords a dimeric species 2 featuring two trans-[PdCl2]
fragments and two diphosphaferrocenes. Reaction of 2 with [Pd(dba)2] yields a trimetallic complex 3. An X-ray crystal structure
study reveals that 3 features a central palladium atom that does not interact with the two peripheral [PdCl2] fragments. Complex 3
can also be formed from the reaction of two equivalents of [Pd(COD)Cl2] with the bis-(octa-n-propyl-diphosphaferrocene)Pd(0)
complex.
# 2003 Elsevier B.V. All rights reserved.
Keywords: Crystal structures; Diphosphaferrocene; Palladium complexes
1. Introduction
of the octa-n-ethyl-diphosphaferrocene. Thus, complex
I allows the coupling between pinacolborane and
iodoarenes (Myaura’s coupling process) to yield the
corresponding arylboronic esters in very good yields
(TON about 3000) [5] and dimer II catalyzes the Suzuki
cross-coupling reaction between phenylboronic acid and
Though diphosphaferrocenes were discovered more
than 20 years ago [1], their coordination chemistry
remained largely unexplored for a long time [2]. This
situation mainly results from the difficulty to control the
reactivity of the two phosphorus atom lone pairs
towards metallic fragments that possess more than one
vacant coordination site. Cowley and coworkers [3] and
some of us [4] showed that the introduction of sub-
stituents at the a-positions at phosphorus plays a crucial
role in preventing the formation of polymeric materials.
Thus, octa-n-alkyl-substituted diphosphaferrocenes can
now be used to build well-defined polymetallic edifices
and unusual chelate complexes involving a side-on
coordination mode of the ligand. From these studies,
it appeared that combination of the ferrocenyl back-
bone, steric effects provided by the substituents, and the
high 3s-character of the phosphorus atom lone pair
could be exploited to devise efficient catalytic systems.
The two most significant applications were obtained by
studying the catalytic potential of palladium complexes
various bromoarenes (TON about 1ꢀ
106) [6].
/
In pursuing our investigations on the reactivity of
these two types of palladium complexes, we recently
found that they can be used to build surprising
trimetallic edifices incorporating both Pd(II) and Pd(0)
centers. Herein we report on theses results.
2. Results and discussion
All experiments were carried out with the highly
soluble octa-n-propyl-diphosphaferrocene (1) ligand
which is readily available following the zirconium
mediated route devised for the synthesis of the octa-n-
ethyl derivative [7]. Palladium complexes 2 and 3,
* Corresponding authors. Tel.: ꢁ
33-3990.
E-mail address: dcph@poly.polytechnique.fr (P. Le Floch).
/
33-1-69-33-4079; fax: ꢁ33-1-69-
/
0022-328X/03/$ - see front matter # 2003 Elsevier B.V. All rights reserved.
doi:10.1016/S0022-328X(03)00524-2

190
M. Melaimi et al. / Journal of Organometallic Chemistry 684 (2003) 189ꢂ193
/
analogs to I and II, were thus conventionally prepared
by reacting with the appropriate amounts of
[Pd(COD)Cl2] and [Pd(dba)2] complexes, respectively.
1
Their syntheses are depicted in Eqs. (1) and (2).
ð1Þ
ð2Þ
Fig. 1. ORTEP view of one molecule of complex 4. Ellipsoids are scaled
to enclose 50% of the electron density. The ethyl part of each n-propyl
group has been omitted for clarity. The numbering is arbitrary and
different from that used in the assignment of NMR spectra.
based chelate complexes, the deviation from the ideal
in-plane coordination of the two phosphorus atom lone
Both complexes were successfully characterized by
means of NMR spectroscopy and elemental analyses.
Their NMR data which are very similar to that of their
n-ethyl counterparts do not deserve further comments.
The reaction of dimer 2 with one equivalent of
[Pd(dba)2] in THF at room temperature led to a
surprising result. Upon addition of the complex, a
dark insoluble precipitate formed. The formulation of
this complex 4 turned out to be difficult to establish
exclusively on the basis of NMR data which show that
the structure presents a high symmetry. The most
significant structural information was given the 31P-
NMR spectrum which shows a strong upfield shift
pairs is very large (Uꢄ428). It must be noted that this
/
non-directional bonding, which results from the pro-
nounced spherical character of the phosphorus atom
Table 1
Crystal data and structural refinement details for the structure of
compound 4
Empirical formula
Fw
Temperature (K)
C64H112Cl4Fe2P4Pd3
1578.12
150.0(10)
0.71069
monoclinic
P21/n
˚
Wavelength (A)
Crystal system
Space group
Unit cell dimensions
[d(CDCl3): ꢃ
/
9.0 ppm for 2 and d(CDCl3): ꢃ78.0
/
ppm for 4]. As previously noted, such a shielding is
generally encountered in complexes incorporating a
chelated diphosphaferrocene ligand. Fortunately, crys-
tals of 4 could be grown from a slow diffusion of
hexanes in a dichloromethane solution of the complex.
An ORTEP view of one molecule of 4 is presented in Fig.
1 and the most significant metric data are listed in Table
1.
˚
a (A)
15.058(5)
15.802(5)
16.442(5)
90.000(5)
116.250(5)
90.000(5)
3508.8(19)
2
˚
b (A)
˚
c (A)
a (8)
b (8)
g (8)
3
V (A )
˚
Z
Dcalcd (g cmꢃ3
m (cmꢃ1
)
1.494
1.437
)
Consistent with NMR data, the structure of 4 is
symmetrical. Contrary to what could be initially en-
visaged, no disproportionation (leading to a Pd(I)
dimer) had taken place and complex 4 is a trimetallic
species incorporating two PdCl2 fragments and a central
palladium atom. This edifice results from the insertion
of palladium atom in the cavity of dimer 2. This quite
unusual arrangement obviously deserves several com-
ments. A first important point concerns the binding of
the two phosphorus atom lone pairs to the two PdCl2
fragments. As can be seen in Fig. 1, the two ligands are
now coordinated in trans fashion, the overall geometry
around the two palladium atoms remaining square-
planar. As previously noted in diphosphaferrocene-
h, k, l ranges
ꢃ
/
215
23
0.12ꢀ
/
h 5
/
21, ꢃ
/
225
/
k 5
/
17, ꢃ
/
235
/
l 5
/
Crystal size (mm3)
Cryst color and habit
2Umax (8)
No. of ref. measured
No. of ind. refl.
/
0.12ꢀ
/0.12
deep purple cube
30.03
27 305
10 257
8969
No. of ref. used
a
R1 [I ꢀ
/
2s(I)]
2s(I)]
0.0228
0.0635
1.016
b
wR2 [I ꢀ
/
GOF on F2
Largest diff. peak
ꢃ3
0.677 (0.073), ꢃ0.913 (0.073)
/
˚
(e A
)
a
R1ꢄ
wR2ꢄ
/
ajjF0jꢃ
/
jFcjj/ajF0j.
2
/
b
2 1/2
/
(awjjF0jꢃ
jFcjj /awjF0j )
.

M. Melaimi et al. / Journal of Organometallic Chemistry 684 (2003) 189ꢂ
/
193
191
lone pair, has also been observed in other sp2-hybridized
ligands such as phosphinines [8]. The most striking
feature of 4 undoubtedly concerns the central palladium
atom which adopts a square-planar geometry. Examin-
ing the metric parameters, it is obvious that no bonding
occurs between this atom and the two PdCl2 fragments,
Table 2
Selected bond distances (A) and angles (8) for complex 4
˚
˚
Bond distances (A)
P(1)ÃC(1)
C(1)Ã
C(2)Ã
C(3)Ã
C(4)Ã
P(2)Ã
C(5)Ã
C(6)Ã
C(7)Ã
C(8)Ã
P(1)Ã
P(2)Ã
C(1)Ã
C(2)Ã
C(3)Ã
C(4)Ã
C(5)Ã
C(6)Ã
C(7)Ã
C(8)Ã
Ct(1)Ã
Ct(2)Ã
P(1)Ã
P(1)Ã
P(2)Ã
P(2)Ã
P(1?)Ã
P(1?)Ã
P(2?)Ã
Pd(2)Ã
Pd(2)Ã
Pd(1)Ã
Pd(1)Ã
/
1.764(2)
1.419(2)
1.442(2)
1.421(2)
1.760(2)
1.765(1)
1.419(2)
1.442(2)
1.423(2)
1.762(2)
2.2976(6)
2.2873(7)
2.116(2)
2.114(2)
2.111(1)
2.117(1)
2.127(2)
2.110(1)
2.095(2)
2.112(2)
1.688
/
C(2)
C(3)
C(4)
P(1)
/
/
the intramolecular PdÃ
/
Pd distance being too long at
3.336 A. Additionally, no dative bonding occurs be-
/
˚
/C(5)
tween this palladium atom and the two iron atoms of
˚
Fe(1)ꢄ3.20(1) A).
/
C(6)
C(7)
C(8)
P(2)
/
each ligand (for example, d Pd(1)Ã
/
/
/
Indeed, the PdÃ
bonding are usually shorter [9]. Surprisingly, it clearly
appears that the PÃPd bonds are not strictly equivalent.
Thus the P(2)ÃPd(1) and P(2?)ÃPd(1) bond distances
(2.5160(7) A) are slightly longer than P(1)ÃPd(1) and
Pd(1) (2.4304(7) A) (Table 2). This dissymmetry is
not apparent in the other PdÃP and PdÃCl bond
/
Fe bonds in complexes involving such
/
/Fe(1)
/
/Fe(1)
/
/
/
Fe(1)
Fe(1)
Fe(1)
Fe(1)
Fe(1)
Fe(1)
Fe(1)
Fe(1)
˚
/
/
/
˚
P(1?)Ã
/
/
/
/
/
lengths, which are nearly comparable, and it likely
results from packing forces in the crystal. It must also
be precised that a 31P-NMR study revealed that the
overall geometry of 4 remains highly symmetrical in
/
/
/
/Fe(1)
/Fe(2)
1.695
solution, even at ꢃ80 8C. At last, we also noted a small
/
/
Pd(1)
Pd(2?)
Pd(1)
Pd(2)
2.4305(7)
2.2271(6)
2.5160(7)
2.2334(7)
2.4304(7)
2.2271(6)
2.5161(7)
2.3466(8)
2.3548(7)
3.020(1)
3.0195(8)
out of plane distortion of the two P atoms from the
plane defined by the four carbone atoms of the ring
/
/
/
(Uꢄ68 in 4 vs 1.28 in 1). Apart from that, all metric
/
/
Pd(1)
Pd(2)
Pd(1)
parameters in the two diphosphaferrocene moieties are
nearly identical with those previously noted in other
palladium complexes.
Knowing the structure of 4, it seemed logical to
attempt its synthesis from the reaction of the bis(dipho-
sphaferrocene)Pd(0) (3) complex with a source of
[PdCl2] (Eq. (3)). The reaction cleanly proceeded in
THF with [Pd(COD)Cl2] at room temperature to yield 4
as efficiently as obtained using the above-mentioned
method (Eq. (4)).
/
/
/
Cl(1)
Cl(2)
Fe(1)
Fe(1?)
/
/
/
Bond angles (8)
P(1)ÃC(1)ÃC(2)
C(1)ÃC(2)Ã
C(2)ÃC(3)Ã
C(3)ÃC(4)Ã
C(4)ÃP(1)Ã
Pd(2)ÃP(2)Ã
Pd(2)ÃP(1?)Ã
P(1)ÃPd(1)Ã
P(1)ÃPd(1)Ã
P(1)Ã
P(2)Ã
P(1)Ã
P(1)Ã
P(1)Ã
P(2)Ã
P(2)Ã
Cl(1)Ã
/
/
109.4(1)
113.3(1)
113.6(1)
109.3(1)
93.81(7)
89.05(2)
91.40(2)
96.13(2)
180.00(1)
95.68(2)
180.00(1)
83.88(2)
83.15(2)
175.58(1)
175.00(1)
86.92(2)
94.57(2)
/
/
C(3)
C(4)
P(1)
/
/
/
/
/
/
C(1)
Pd(1)
Pd(1)
/
/
/
/
/
/P(2)
ð3Þ
/
/P(1?)
/
Pd(2?)Ã
Pd(1)Ã
Pd(1)Ã
Pd(2?)Ã
Pd(2?)Ã
/P(2?)
/
/Pd(2?)
/
/P(2?)
/
/Cl(1?)
/
/Cl(2?)
/
Pd(2)Ã
/Cl(1)
ð4Þ
/
Pd(2)Ã
/Cl(2)
/
Pd(2)ÃCl(2)
/
The particular structural arrangement of 4 obviously
raises the problem of the electron-counting. If we
assume that each diphosphaferrocene ligand simply
contributes through its two phosphorus atom lone pairs
to bind the [PdCl2] fragments (16 e), no electron remain
to complete the coordination sphere of the central
palladium atom. However, as already observed in
palladium(II) and Ga(III) complexes, diphosphaferro-
cenes do not exclusively behave as 4-electron donor
ligands. A theoretical study carried out on a chelate
complex of the [GaCl2]ꢁ fragment (isolobal of a PdL2
fragment) demonstrated that several hybrid orbitals
resulting from the combination of 3s, 3px, 3pz orbitals
at phosphorus and the 3dxz orbital at iron can be
involved in the binding to the metal. Furthermore, these
calculations also showed that the out of plane distortion
of the P atoms (found in 4: see above in the discussion of
the X-ray structure) reflects the participation of the PÃ
/

192
M. Melaimi et al. / Journal of Organometallic Chemistry 684 (2003) 189ꢂ193
/
2
Fe bond in the bonding to the metal. Therefore, we can
reasonably propose that in 4, each diphosphaferrocene
contributes with more than two electrons leaving a 14-
or 18-electron central palladium atom [10]. Calculations
are currently underway in our laboratories to clarify this
point.
CH2Ã
32.7 (s, CH2Ã
1JPC
23.6 Hz, PÃ
/
CH3), 32.6 (d, JCP
CH2ÃCH3), 93.1 (s, PÃ
C ÄC) ppm; Anal. Calcd for
ꢄ
/
3.7 Hz, CH2Ã
/
CH2Ã
/
CH3),
/
/
/
CÄC), 100.1 (bs, S
/
ꢄ
/
/
/
C64H112Cl4Fe2P4Pd2: C, 52.23; H, 7.67. Found: C,
51.75; H, 7.79%.
3.3. Synthesis of the bis-(octa-n-propyl-
diphosphaferrocene)palladium(0) complex (3)
3. Experimental
Diphosphaferrocene 1 (111 mg, 0.2 mmol) was
reacted with [Pd(dba)2] complex (57 mg, 0.1 mmol) in
dichloromethane (5 ml) at room temperature. After 20
min, 31P-NMR spectroscopy showed the total conver-
sion of 1 into complex 3. After evaporation of the
solvent, complex 3 was washed with dry acetonitrile
3.1. General considerations
All reactions were routinely performed under an inert
atmosphere of argon or nitrogen by using Schlenk and
glove-box techniques and dry deoxygenated solvents.
Dry THF and hexanes were obtained by distillation
from Na/benzophenone and dry CH2Cl2, CDCl3 and
acetonitrile from P2O5. Dry CD2Cl2 was stored, like
(2ꢀ
/
5 ml) and then dried under vacuum and recovered
as a dark green powder. Yield: 120 mg (98%).31P-NMR
(121.5 MHz, CDCl3): d ꢃ
122 ppm. 1H-NMR (300
/
MHz, CDCl3): d 0.77 (t, 24H, 3JHH
ꢄ7.1 Hz, CH3), 0.99
/
˚
CDCl3, on 4 A Linde molecular sieves. Nuclear mag-
3
netic resonance spectra were recorded on a Bruker
Avance 300 spectrometer operating at 300 MHz for
1H, 75.5 MHz for 13C and 121.5 MHz for 31P. Solvent
peaks are used as internal reference relative to Me4Si for
1H and 13C chemical shifts (ppm); 31P chemical shifts are
relative to a 85% H3PO4 external reference. The follow-
ing abbreviations are used: b; broad, singlet; d, doublet;
t, triplet; m, multiplet; p, pentuplet; sext, sextuplet; sept,
septuplet; v, virtual. Mass spectra were obtained at 70
eV with a HP 5989B spectrometer coupled to a HP 5980
chromatograph by the direct inlet method. Elemental
analyses were performed by the ‘‘Service d’analyse du
CNRS’’, at Gif sur Yvette, France. [Pd(COD)Cl2] [11]
and [Pd(dba)2] [12] were prepared according to pub-
lished procedures.
(t, 24H, JHH
ꢄ
/
7.3 Hz, CH3), 1.21 (m, 16H, S JHH
CH3), 1.38 (m, 16H, S JHH 55.3 Hz,
10.5 Hz, CH2Ã
2JHP
52.1 Hz,
CH2CH3), 2.40 (m, 8H, S JHH 47.6 Hz,
CH2CH3) ppm. 13C-NMR (75.5 MHz, CDCl3):
d 15.2 (s, CH3), 16.0 (s, CH3), 26.1 (s, CH2ÃCH3),
CH2Ã
C), 129.4
C) ppm; Anal. Calcd for
ꢄ
/
30.7 Hz, CH2Ã
CH2ÃCH3), 1.62 (t, 16H, JHH
CH2CH3), 1.98 (m, 8H, S JHH
CHHÃ
CHHÃ
/
ꢄ
/
2
/
ꢄ
/
/
ꢁ
/
S
ꢄ
/
/
ꢄ
/
/
/
2
29.1(s, CH2Ã
/
CH3), 30.6 (d, JCP
CH2ÃCH3), 99.3 (s, PÃ
43.7 Hz, PÃC Ä
ꢄ
/
5.1 Hz, CH2Ã
/
/
CH3), 31.6 (s, CH2Ã
/
/
/
CÄ
/
1
(d, JPC
ꢄ
/
/
/
C64H112Fe2P4Pd: C, 62.82; H, 9.23. Found: C, 62.55;
H, 9.06%.
3.4. Syntheses of complex (4)
Complex 4 can be prepared following two different
procedures. The first one involves the reaction of dimer
2 (120 mg, 82 mmol) with [Pd(dba)2] (47 mg, 82 mmol) in
THF at room temperature. After 3 h stirring, a black
solid precipitated and the 31P-NMR spectrum of an
aliquot of the crude mixture showed no NMR signals
indicating the end of the reaction. The solution was then
filtrated yielding a black solid. After washings with THF
3.2. Synthesis of the [(octa-n-propyl-
diphosphaferrocene)PdCl2]2 dimer (2)
Diphosphaferrocene 1 (100 mg, 0.18 mmol) and
[Pd(COD)Cl2] (51 mg, 0.18 mmol) were reacted in
dichloromethane (4 ml) at room temperature. After 10
min, 31P-NMR spectroscopy showed the univocal for-
mation of complex 2. After evaporation of the solvent,
the dark residue obtained was washed three times with
(3ꢀ5 ml), the black solid obtained was dried under
/
vacuum. Yield: 122 mg (95%). The second procedure
involves the reaction of the zerovalent palladium(0) (122
mg, 0.1 mg) complex 3 with two equivalents of
[Pd(COD)Cl2] (55.6 mg, 0.2 mmol). The reaction takes
place in THF as solvent. After 2 h stirring at room
temperature, a black powder precipitated. The solution
was then filtrated and the black solid obtained was
hexanes (3ꢀ5 ml) to remove released COD. After
/
drying under vacuum, dimer 2 was isolated as a deep-
purple solid. Yield: 128 mg (97%).31P-NMR (121.5
MHz, CDCl3): d ꢃ
/
9.0 ppm. 1H-NMR (300 MHz,
3
CDCl3): d 0.81 (t, 24H, JHH
ꢄ
/
7.8 Hz, CH3), 1.09 (t,
32.1
40.2 Hz, CH2Ã
12.5 Hz, CH2ÃCH2CH3),
2JHP
47.1 Hz, CHHÃ
CH2CH3), 2.38 (m, 8H, S JHH 49.8 Hz, CHHÃ
CH2CH3) ppm. 13C-NMR (75.5 MHz, CDCl3): d 17.3
(s, CH3), 17.7 (s, CH3), 27.9 (s, CH2ÃCH3), 30.8 (s,
3
24H, JHH
Hz, CH2ÃCH3), 1.30 (m, 16H, S JHH
CH3), 1.72 (t, 16H, JHH
2.01 (m, 8H, S JHH
ꢄ
/
7.1 Hz, CH3), 1.17 (m, 16H, S JHH
ꢄ
/
/
ꢄ
/
/
washed with THF (2ꢀ
method, complex 4 was isolated as a black solid. Yield:
125 mg (97%).31P-NMR (121.5 MHz, CD2Cl2): d ꢃ
78
ppm. H-NMR (300 MHz, CD2Cl2): d 0.82 (t, 24H,
3JHH 7.3 Hz, CH3), 0.92 (t, 24H, 3JHH
7.6 Hz, CH3),
1.29 (m, 16H, S JHH 22.8 Hz, CH2ÃCH3), 1.45 (m,
/5 ml). Like in the former
2
ꢄ
/
/
ꢁ
/
S
ꢄ
ꢄ
/
/
/
1
/
/
ꢄ
/
ꢄ
/
/
ꢄ
/
/

M. Melaimi et al. / Journal of Organometallic Chemistry 684 (2003) 189ꢂ
/
193
193
(d) S.M. Al-Taweel, Phosphorus, Sulfur Silicon 130 (1997) 203;
(e) A.J. Ashe, III, S. Al-Ahmad, S. Pilotek, D.B. Puranik, C.
Elschenbroich, A. Behrendt, Organometallics 14 (1995) 2689;
(f) R.M.G. Roberts, J. Silver, A.S. Wells, Inorg. Chim. Acta 119
(1986) 165;
16H, S JHH
2JHH
9.2 Hz, CH2Ã
2JHP
41.6 Hz, CHHÃ
JHH
38.4 Hz, CHHÃ
CH2CH3) ppm. 13C-NMR (75.5
MHz, CD2Cl2): d 14.6 (s, CH3), 14.7 (s, CH3), 24.4 (s,
CH2ÃCH3), 26.9 (s, CH2ÃCH3), 28.6 (bs, CH2ÃCH2Ã
CH3), 29.9 (s, CH2ÃCH2Ã 10.5
Hz, PÃCÄC), 108.3 (d, JPC C) ppm;
ꢄ
/
42.9 Hz, CH2Ã
CH2CH3), 1.93 (m, 8H, S JHH
CH2CH3), 2.28 (m, 8H, S
/
CH3), 1.54 (t, 16H,
ꢄ
/
/
ꢁ
/
S
ꢄ
/
/
ꢄ
/
/
(g) B. Deschamps, L. Ricard, F. Mathey, J. Organomet. Chem.
548 (1997) 17;
/
/
/
/
2
(h) C. Ganter, L. Brassat, B. Ganter, Chem. Ber/recl. 130 (1997)
1771;
/
/
CH3), 80.8 (d, JPC
ꢄ
/
1
/
/
ꢄ
/
19 Hz, PÃ
/
C Ä
/
(i) C. Ganter, L. Brassat, B. Ganter, Tetrahedron 8 (1997) 2607;
(j) L. Brassat, B. Ganter, C. Ganter, Chem. Eur. J. 4 (1998) 2148;
Anal. Calcd for C64H112Fe2P4Pd3: C, 48.71; H, 7.15.
Found: C, 48.39; H, 6.92%.
(k) C. Ganter, L. Brassat, C. Glinsbockel, B. Ganter, Organo-
¨
metallics 16 (1997) 2862;
(l) C. Ganter, C. Glinsbockel, B. Ganter, Eur. J. Inorg. Chem. 8
¨
(1998) 1163;
3.5. X-ray structural determination
(m) C. Ganter, C. Kaulen, U. Englert, Organometallics 18 (1999)
5444;
Single crystals of compound 4 suitable for X-ray
crystallography were obtained at room temperature by
diffusing hexane into a dichloromethane solution of the
compound in a sealed tube. Data were collected on a
(n) C.E. Garrett, G.C. Fu, J. Org. Chem. 62 (1997) 4534;
(o) S. Qiao, D.A. Hoic, G.C. Fu, Organometallics 17 (1998) 773;
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(q) K. Tanaka, S. Qiao, M. Tobisu, M.M.-C. Lo, G.C. Fu, J. Am.
Chem. Soc. 122 (2000) 9870;
Nonius Kappa CCD diffractometer using an Moꢂ
/
Ka
˚
0.71069 A) X-ray source and a graphite mono-
(lꢄ
/
(r) R. Shintani, M.M.-C. Lo, G. Fu, Org. Lett. 2 (2000) 3695;
chromator. Experimental details are described in Table
1. The crystal structures were solved using SIR-97 [13]
and SHELXL-97 [14]. ORTEP drawings were made using
ORTEP III for Windows [15].
For selected references concerning phosphaferrocenes and dipho-
sphaferrocenes, see:
[3] D.A. Atwood, A.H. Cowley, S.M. Dennis, Inorg. Chem. 32
(1993) 1527.
[4] X. Sava, L. Ricard, F. Mathey, P. Le Floch, Chem. Eur. J. 7
(2001) 3159.
4. Supplementary material
[5] M. Melaimi, F. Mathey, P. Le Floch, J. Organomet. Chem. 640
(2001) 197.
Crystallographic data for compound 4 have been
deposited with the Cambridge Crystallographic Data
Center, CCDC No. Copies of this information may be
obtained free of charge from the Director, CCDC, 12
[6] X. Sava, L. Ricard, F. Mathey, P. Le Floch, Organometallics 19
(2000) 4899.
[7] X. Sava, M. Melaimi, N. Me´zailles, L. Ricard, F. Mathey, P. Le
Floch, New J. Chem. 26 (2002) 1378.
[8] P. Le Floch, L. Ricard, F. Mathey, Bull. Soc. Chim. Fr. 133
(1996) 691.
Union Road, Cambridge, CB2 1EZ, UK (Fax: ꢁ44-
/
1223-336033; e-mail: deposit@ccdc.cam.a-c.uk or www:
http://www.ccdc.cam.ac.uk).
[9] (a) D. Seyferth, B.W. Hames, T.G. Rucker, M. Cowie, R.S.
Dickson, Organometallics 2 (1983) 472;
(b) S. Akabori, T. Kumagai, T. Shirahige, S. Sato, K. Kawazoe,
D. Tamura, Organometallics 6 (1987) 526;
(c) S. Akabori, T. Kumagai, T. Shirahige, S. Sato, K. Kawazoe,
D. Tamura, Organometallics 6 (1987) 2105;
Acknowledgements
(d) M. Sato, K. Suzuki, S. Akabori, Chem. Lett. (1987) 2239.;
(e) M. Cowie, R. Dickson, J. Organomet. Chem. 326 (1987) 269;
(f) M. Sato, M. Sekino, J. Organomet. Chem. 344 (1988) C31;
The authors would like to thank Prof. P. Braunstein,
University of Strasbourg, France, for helpful discus-
sions. This work was supported by the CNRS and the
Ecole Polytechnique.
For references about dative bonding between Fe in ferrocenes and
palladium atoms, see for example:
[10] P. Braunstein, N.M. Boag, Angew. Chem. Int. Ed. 40 (2001) 2433
For a reference concerning bridging phosphines in high-symmetry
polymetallic complexes, see:
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