Platinum complexes of heteroannularly bridged heterobidentate ferrocenyl diphosphine ligands: Their molecular structure and their use in catalytic carbonylation reactions

Article abstract of DOI:10.1016/S0022-328X(99)00584-7

Platinum complexes PtCl₂(L) and PtCl(SnCl₃)(L) of the ferrocenyl diphosphine ligands (L) (R,R)-1-diphenylphosphino-2,1′-[(1-diphenylphosphino)-1,3-propanediyl]- ferrocene (1), (R,R)-1-diphenylphosphino-2,1′-[(1-dicyclohexylphosphino)-1,3-propanediyl] -ferrocene (2), (R,R)-1-bis(4-fluorophenyl)phosphino-2,1′-[(1-diphenylphosphino)-1,3- propanediyl]-ferrocene (3), have been synthesised. Complexes PtCl₂(1) and PtCl₂(2) have been structurally characterised by X-ray diffraction. Both the 'preformed' and the in situ catalysts have been used in hydroformylations of styrene. At low temperature (below 70°C) and with use of the platinum catalysts the prevailing formation of (R)-2-phenyl-propanal was observed, while at higher temperatures the formation of the (S)-enantiomer was favoured. The palladium catalysts proved to be rather inactive in the hydromethoxycarbonylation of styrene. In the presence of ligand 2 the predominant formation of the linear regioisomer was observed.

Full text of DOI:10.1016/S0022-328X(99)00584-7

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Journal of Organometallic Chemistry 595 (2000) 93–101
Platinum complexes of heteroannularly bridged heterobidentate
ferrocenyl diphosphine ligands: their molecular structure and their
use in catalytic carbonylation reactions
Thomas Sturm a, Walter Weissensteiner a,*, Kurt Mereiter b, Tama´s Ke´gl c,
Gyo¨rgy Jeges d, Gyo¨rgy Petolz e, La´szlo´ Kolla´r e,f,1
3
a Institute of Organic Chemistry, Uni6ersity of Vienna, Wa¨hringer Straße 38, A-1090 Vienna, Austria
b Institute of Mineralogy, Crystallography and Structural Chemistry, Technical Uni6ersity of Vienna, Getreidemarkt 9, A-1040 Vienna, Austria
c Research Group for Petrochemistry of the Hungarian Academy of Sciences, PO Box 158, H-8201 Veszpre´m, Hungary
d Department of Chemistry, Uni6ersity of Veszpre´m, PO Box 158, H-8201 Veszpre´m, Hungary
e Department of Inorganic Chemistry, Janus Panonius Uni6ersity, PO Box 266, H-7624 Pe´cs, Hungary
f Research Group for Chemical Sensors of the Hungarian Academy of Sciences, PO Box 266, H-7624 Pe´cs, Hungary
Received 19 May 1999; received in revised form 16 June 1999; accepted 22 September 1999
Abstract
Platinum complexes PtCl2(L) and PtCl(SnCl3)(L) of the ferrocenyl diphosphine ligands (L) (R,R)-1-diphenylphosphino-2,1%-[(1-
diphenylphosphino)-1,3-propanediyl]-ferrocene (1), (R,R)-1-diphenylphosphino-2,1%-[(1-dicyclohexylphosphino)-1,3-propanediyl]-
ferrocene (2), (R,R)-1-bis(4-fluorophenyl)phosphino-2,1%-[(1-diphenylphosphino)-1,3-propanediyl]-ferrocene (3), have been
synthesised. Complexes PtCl2(1) and PtCl2(2) have been structurally characterised by X-ray diffraction. Both the ‘preformed’ and
the in situ catalysts have been used in hydroformylations of styrene. At low temperature (below 70°C) and with use of the
platinum catalysts the prevailing formation of (R)-2-phenyl-propanal was observed, while at higher temperatures the formation
of the (S)-enantiomer was favoured. The palladium catalysts proved to be rather inactive in the hydromethoxycarbonylation of
styrene. In the presence of ligand 2 the predominant formation of the linear regioisomer was observed. © 2000 Elsevier Science
S.A. All rights reserved.
Keywords: Carbonylation; Hydroformylation; Platinum; Palladium; Ferrocene; Phosphine; Nuclear magnetic resonance
1. Introduction
Hundreds of ligands with different steric and elec-
tronic properties, shapes and functionalities have al-
ready been tested in various homogeneous catalytic
reactions [7], including carbonylation reactions [8,9].
In addition to C2 symmetrical chiral diphosphines
[10–16] also asymmetric diphosphines with phosphino
groups in different chemical environments were found
to be efficient ligands in enantioselective hydroformy-
lation [17].
Complexes of ferrocene-based chiral diphosphines
have also been intensively tested and found to be
active catalysts in a variety of enantioselective reac-
tions including hydrogenation, hydrosilylation, cross-
coupling reactions, aldol condensation and others
[18]. Surprisingly, the exploitation of ferrocene-based
ligands in enantioselective carbonylation is almost un-
precedented [19,20].
The importance of carbonylation reactions has ini-
tiated many studies describing mainly the range of
applicability as well as mechanistic considerations [1,2].
In particular, a large number of simple and function-
alised olefins have been investigated aiming primarily
towards compounds of practical interest [3]. Large efforts
have been made to apply carbonylations and especially
hydroformylations to the synthesis of chiral building
blocks and biologically important derivatives [4–6].
* Corresponding author. Tel.: +43-1-4277-52111; fax: +43-1-
4277-9521.
E-mail address: walter.weissensteiner@univie.ac.at (W. Weis-
sensteiner)
1 Also corresponding author.
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00584-7

94
T. Sturm et al. / Journal of Organometallic Chemistry 595 (2000) 93–101
In this paper we describe the synthesis and character-
respectively (Scheme 2). In dichloromethane one Pt–Cl
bond of these PtCl2(L) complexes inserts tin(II)chloride
yielding PtCl(SnCl3)(L)-type products. The solubility
of these complexes is unexpectedly low. While
PtCl(SnCl3)(2) and PtCl(SnCl3)(3) were crystallised
slowly from the reaction mixture, PtCl(SnCl3)(1)
proved to be practically insoluble in halogenated sol-
vents and precipitated immediately upon addition of
SnCl2.
isation of platinum complexes modified with racemic
and enantiopure heteroannularly bridged ferrocenyl
diphosphine ligands and discuss their application in
platinum-catalysed hydroformylation. We also report
on palladium-catalysed hydroalkoxycarbonylation re-
actions.
2. Results and discussion
The 31P-NMR spectra of the PtCl2(L) complexes
show a characteristic pair of doublets corresponding to
an AX spin system. Each of these lines is flanked by
platinum satellites resulting in a characteristic 1/4/1
2.1. Synthesis of ferrocenyl ligand 3
1
Like 1 and 2 [21,22], enantiopure 3 has been synthe-
sised in two steps from enantiopure (R)-1,1%-[(1-
dimethylamino)propanediyl]-ferrocene, 4 (Scheme 1).
Lithiation of 4 with n-BuLi and quenching with chloro-
bis(para-fluorophenyl)-phosphine led to the amino-
phosphine 5 which on further reaction with di-
phenylphosphine in acetic acid gave the diphosphine
ligand 3.
pattern with J(31P,195Pt) coupling constants of about
3700 and 3500 Hz for 1a, 3a and 2a, respectively,
clearly indicating the presence of the chloro ligands
trans to phosphorus.
The in situ tin(II)chloride insertion reaction was fol-
lowed by 31P-NMR and revealed some differences in
reactivity and selectivity of the PtCl2(L) complexes. The
dichloro platinum complexes 1a, 2a and 3a were re-
acted with tin(II)chloride giving the insertion products
(the corresponding platinum–trichlorostannato com-
plexes) in 60, 45 and 30% yield.
2.2. Synthesis and NMR characterisation of the
platinum complexes of ferrocenyl ligands 1, 2 and 3
The selectivity of insertion is completely different for
2a and 3a. While in the case of 3a the tin(II)chloride
insertion takes place selectively trans to the phosphorus
attached directly to the Cp ring yielding 3b exclusively,
The enatiomerically pure ligands 1, 2 and 3 were
reacted with PtCl2(PhCN)2 in refluxing benzene result-
ing in the easily isolable complexes 1a, 2a and 3a,
Scheme 1.
Scheme 2.

T. Sturm et al. / Journal of Organometallic Chemistry 595 (2000) 93–101
95
Table 1
NMR data of the platinum complexes of ligands 1–3 a
b
c
lPA (ppm)
lPB (ppm)
J(195Pt,31PA)
J(195Pt,31PB)
J(PA–PB)
J(PA–Sn) d
J(PB–Sn)
(Hz)
(Hz)
(Hz)
(Hz)
(Hz)
1 e
−22.3
−23.8
−24.6
−2.0
−6.6
9.65
−5.87
34.4
–
–
–
3375
–
–
–
3715
79.7
27.7
83.0
19.5
–
–
–
–
–
–
–
–
2 e
3 e
PtCl2(1) 1a
e
e
PtCl(SnCl3)(1) 1b
1c
−10.2
−9.1
27.3
10.2
ca. 3300
ca. 2850
ca. 3600
ca. 3400
24.0
25.6
PtCl2(2) 2a
−0.4
47.0
3570
3527
16
–
–
PtCl(SnCl3)(2) 2b
2c
8.5
0.2
59.4
53.7
2931
3446
3426
2921
16
15
4220, 4408
205
193
3630, 3812
PtCl2(3) 3a
−4
34
33
3381
2681
3690
3441
20.2
20
–
–
e
e
PtCl(SnCl3)(3) 3b
−4.8
a Spectra were measured in CDCl3, 1b and 1c in DMSO-d6.
b PA, PAr2 attached to the Cp ring.
c PB, PAr2 or PCy2 attached to the trimethylene bridge.
d 117Sn and 119Sn satellites are separately detectable for Jtrans but coincide for Jcis
e Unresolved because of low solubility and/or low resolution.
.
a 40:60 mixture of 2b and 2c was formed starting from
2a. Since 1b and 1c proved to be completely insoluble
in CDCl3 and CD2Cl2, NMR measurements were car-
ried out in DMSO-d6. Neither 1b nor 1c could be
observed in this solvent since the equilibrium (1) lies by
far on the left side and only the typical AX spin system
of 1a was observed. However, both trichlorostannato
complexes 1b and 1c were obtained in about 90%
conversion upon addition of a tenfold excess of
tin(II)chloride.
ble orange solvates 1a·CHCl3 and 2a·CHCl3, which
were investigated by X-ray diffraction. They crystallise
in the centrosymmetric monoclinic space groups P21/n
and P21/c, respectively, each with four symmetry equiv-
alent formula units in the unit cell. Crystallographic
and experimental data are given in Table 2. Plots of the
molecular structures are shown in Figs. 1 and 2. Se-
lected geometric data are presented in Table 3. The
general structural features of the ferrocenyl ligands are
similar to those of related heteroannularly bridged
derivatives [21]. The Cp rings of both complexes adopt
approximately eclipsed configurations. The C3 bridges
linking the Cp rings force them into a tilted configura-
tion with Cp–Cp tilt angles of 9.8(2)° (1·HCl3) and
10.4(2)° (2a·CHCl3). In addition, the benzylic C atoms
are significantly displaced out of the Cp ring planes and
1a+SnCl2 X 1b+1c
(1)
Only in the case of 2b and 2c could the formation of a
direct platinum–tin bond unequivocally be shown by
NMR. The presence of both cis and trans tin satellites
in the 31P-NMR spectra (2Jcis(117,119Sn,31P):200 Hz
2
117Sn,31P)B2Jtrans
(
119Sn,31P):4000 Hz, re-
,
toward each other: for 1a·CHCl3 by 0.136(5) A (C1)
and Jtrans
(
,
,
and 0.155(6) A (C3), for 2a·CHCl3 by 0.129(4) A (C1)
spectively) is a direct proof of the Pt–SnCl3 moiety
(Table 1). In all other cases either the low resolution
(3b) or the fast exchange of SnCl2 in DMSO (1b, 1c)
,
and 0.166(5) A (C3). The atoms coordinated to plat-
inum (2 P and 2 Cl atoms) exhibit the usual distorted
square planar arrangement. The mean bond lengths of
the PtP2Cl2 squares of the two compounds agree almost
2
made it impossible to determine exactly the J(Sn,P)
coupling constants. However, the Raman spectrum of
PtCl(SnCl3)(1) shows strong bands at 336 and 313
cm−1 (and a weak band at 295 cm−1), which can be
assigned to the Sn–Cl and Pt–Cl bonds, respectively.
,
perfectly, with bond lengths of 2.240 A for the Pt–P
,
bonds of both complexes and with 2.356 and 2.357 A
for the Pt–Cl bonds of 1a·CHCl3 and 2a·CHCl3, re-
spectively. Despite the similar appearance of both com-
plexes in the region of the PtP2Cl2 quadrangles (Figs. 1
and 2), a significant difference in the inclination angle
of the best plane through PtP2Cl2 and through the Cp
(2) ring (C21–C25) does exist, with angles of 27.8(1)° in
1a·CHCl3 and 39.8(1)° in 2a·CHCl3. The difference in
2.3. Structural characterisation of 1a and 2a by X-ray
diffraction
The racemic PtCl2 complexes of 1a and 2a were
recrystallised from CHCl3–hexane yielding the air-sta-

96
T. Sturm et al. / Journal of Organometallic Chemistry 595 (2000) 93–101
these interplanar angles corresponds to positional dif-
Table 2
Crystallographic data for 1a·CHCl3 and 2a·CHCl3
,
,
ferences of 0.4 A for Pt and 0.8 A for Cl, when the
ferrocene moieties, C3 bridges, and P2 atoms of both
complexes are fitted so as to coincide. We attribute this
variation to crystal packing effects and in particular to
remarkable interactions of the CHCl3 solvent molecule
with the PtP2Cl2 quadrangle: in 1a·CHCl3 the CHCl3 is
located abo6e the PtP2Cl2 quadrangle (Fig. 1) showing a
1a·CHCl3
2a·CHCl3
Formula
fw
Crystal size (mm)
Space group
C38H33Cl5FeP2Pt C38H45Cl5FeP2Pt
979.77
0.12×0.24×0.24 0.10×0.14×0.32
P21/n (No. 14)
12.810(4)
18.040(6)
16.410(5)
99.54(2)
3740(2)
4
991.87
P21/c (No. 14)
13.267(4)
15.647(5)
19.576(7)
109.41(2)
3833(2)
4
299(2)
1.719
1968
4.48
,
a (A)
,
bent hydrogen bond C4–H4···Cl2 (C4···Cl2=3.538 A,
,
b (A)
,
H4···Cl2=2.62 A, C4–H4···Cl2=156°) and a weak
,
c (A)
,
Pt···Cl5 interaction of 4.32 A; in 2a·CHCl3 the CHCl3
is located below the PtP2Cl2 quadrangle (Fig. 2) show-
i (°)
3
,
V (A )
Z
ing a bifurcated hydrogen bond C4–H4···Cl1, Cl2
T (K)
299(2)
1.740
1920
4.59
,
,
(C4···Cl1=3.645 A, H4···Cl1=2.80 A, C4–H4···Cl1=
Dcalc (g cm−3
F(000)
)
,
,
145°, C4···Cl2=3.456 A, H4···Cl2=2.63 A, C4–
H4···Cl2=142°) and a weak Pt···Cl3 interaction of 4.59
v(Mo–Kh) (mm−1
)
Absorption correction
Transmission fact.
Min/max
qmax (°)
Index ranges
Multi scan
0.555/0.802
Multi scan
0.557/0.802
,
A. Apart from influencing the specific conformations of
both complexes these interactions between CHCl3 and
the PtP2Cl2 quadrangles may contribute significantly to
the pronounced stability of both compounds against
solvent loss (airstable for months). Fig. 3 shows plots of
superpositions of the complexes with their free ligands
[22]. These plots show that complexation of platinum is
accompanied by the following structural changes: (i) by
a signficant out-of-plane deformation of the P1 atoms
from the Cp rings to which they are attached:
30
30
−185h518
−255k525
−235l523
−185h518
−225k521
−275l527
60 259
11 137
8983
425
0.023
0.039
0.051
No. of reflections measured 58 884
No. of unique reflections 10 858
No. of reflections IB2|(I) 8674
No. of parameters
425
0.027
0.043
0.062
R1 (IB2|(I))
a
R1 (all data)
,
−0.041(3) and 0.105(3) A in the free ligands, 0.330(5)
and 0.344(4) A in the PtCl2 complexes; (ii) by a de-
crease of the P1–P2 distances from 3.49 and 3.69 A in
the free ligands to 3.313(1) A in 1a·CHCl3 and 3.359(1)
b
wR2 (all data)
,
Difference Fourier peaks
−1.06/1.01
−0.69/0.64
,
−3
,
min/max (e A
)
,
a R1=ꢀꢁꢁFoꢁ−ꢁFcꢁꢁ/ꢀꢁFoꢁ.
,
A 2a·CHCl3; and (iii) by a significant rotation of the
b wR2=[ꢀ(w(Fo2−Fc2)2)/ꢀ(w(F2o)2)]1/2
.
Cp-bonded diphenylphosphines about the P1–C22
bond axes bringing the phenyl ring 3 (C31–C36) in
close proximity to H12, a fact which is also causing a
signficant upfield-shift of the NMR signals of this par-
ticular proton. The outlined features of the two com-
plexes are consistent with a relatively stiff ligand
backbone and little conformational freedom in the re-
gion of the PtP2Cl2 quadrangles.
2.4. Homogeneous carbonylation of styrene with
platinum and palladium catalysts
2.4.1. Hydroformylations
Styrene (6) as the model substrate was reacted in the
presence of one of the platinum-containing precursors
1a, 2a or 3a and anhydrous tin(II)chloride with CO–H2
(1:1) at 60–100°C and at a pressure of 100 bar (Table
4).
CO/H
2
PhCH=CH2 ꢀꢀꢀꢁ PhCH(CH3)CHO+Ph(CH2)2CHO
6
7
8
+PhC2H5
(2)
9
In each case in addition to the formyl regioisomers 7
and 8 the hydrogenation product 9 was also formed
(reaction (2), Table 4).
Fig. 1. Structural view of 1a·CHCl3 showing 20% probability thermal
ellipsoids. The CHCl3 solvent molecule and its hydrogen bond to Cl2
(thin dashed line) is included.

T. Sturm et al. / Journal of Organometallic Chemistry 595 (2000) 93–101
97
dependence, a change of the predominating enantiomer
can occur. A second explanation takes into account the
possibility of a ligand flexibility, which in a complex
could result in conformer equilibria. A strong tempera-
ture dependence of such an equilibrium is likely to
influence the face selectivity of a substrate, thus influ-
encing the enantioselectivity and the absolute configu-
ration of the product. In the case of our rigid
heteroannularly bridged ferrocenyl ligands, con-
former equilibria caused by the ligands can be ex-
Table 3
,
Selected bond distances (A) and angles (°) for 1a·CHCl3 and
2a·CHCl3
1a·CHCl3
2a·CHCl3
Bond distances
Pt–P(1)
Pt–P(2)
Pt–Cl(1)
Pt–Cl(2)
2.240(1)
2.240(1)
2.348(1)
2.364(1)
2.237(1)
2.243(1)
2.357(1)
2.356(1)
Fig. 2. Structural view of 2a·CHCl3 showing 20% probability thermal
ellipsoids. The CHCl3 solvent molecule behind the PtP2Cl2 quadran-
gle and its bifurcated hydrogen bond to Cl1 and Cl2 (thin dashed
line) is included.
Fe–C(11)
Fe–C(12)
Fe–C(13)
Fe–C(14)
Fe–C(15)
Fe–C(21)
Fe–C(22)
Fe–C(23)
Fe–C(24)
Fe–C(25)
2.015(3)
2.040(3)
2.054(3)
2.053(3)
2.026(3)
2.016(3)
2.042(3)
2.049(3)
2.046(3)
2.033(3)
2.037
2.019(3)
2.049(3)
2.071(3)
2.041(3)
2.027(3)
2.017(2)
2.053(2)
2.057(3)
2.041(3)
2.024(3)
2.040
Although the activity of the tested platinum catalysts
falls behind that of most of the Pt–diphosphine–
tin(II)chloride systems, the ferrocenyl–diphosphine-
based catalysts proved to be of interest from a
theoretical point of view.
It is worth noting that both the chemoselectivity of
hydroformylation and the regioselectivity towards the
branched aldehyde are significantly influenced by the
basicity of the diphosphine ligands. The use of the most
basic ligand 2 results in the lowest chemo- and regio-
selectivities. Variation of the temperature did not sig-
nificantly change the regioselectivity. However, when 1a
and 2a were used as the catalyst precursor a strong
temperature dependence of the enantioselectivity was
observed. At low temperature the formation of (R)-2-
phenyl-propanal and at higher temperature (above
70°C) that of the (S)-enantiomer is favoured.
P(1)–C(22)
P(1)–C(31)
P(1)–C(41)
P(2)–C(1)
P(2)–C(51)
P(2)–C(61)
1.798(3)
1.812(3)
1.822(3)
1.852(3)
1.815(3)
1.831(3)
1.811(2)
1.814(2)
1.823(3)
1.856(2)
1.865(2)
1.845(2)
Bond angles
P(1)–Pt–P(2)
P(1)–Pt–Cl(1)
P(1)–Pt–Cl(2)
P(2)–Pt–Cl(1)
P(2)–Pt–Cl(2)
Cl(1)–Pt–Cl(2)
95.37(3)
169.09(3)
86.51(3)
91.16(4)
177.88(3)
87.14(4)
97.14(3)
173.23(2)
87.28(3)
88.50(3)
174.98(2)
87.25(3)
Although similar phenomena have previously been
observed for other (C2-symmetrical) bidentate phosphi-
nes [14,16], the temperature dependence of the catalytic
systems with ligands 1 and 2 is remarkable. In general,
the strong temperature dependence of the enantioselec-
tivity of platinum–diphosphine–tin(II)chloride-cat-
alysed hydroformylations is explained by invoking both
kinetic and steric factors. The change in enantiomeric
excess of the product might primarily be determined by
differences in the temperature dependence of the reac-
tion paths involving the diastereomeric transition states
that are formed by coordinating the prochiral substrate
with either its re or its si site to the metal fragment.
When the reaction rates related to these diastereomeric
pathways show a significantly different temperature
Pt–P(1)–C(22)
Pt–P(1)–C(31)
Pt–P(1)–C(41)
C(22)–P(1)–C(31)
C(22)–P(1)–C(41)
C(31)–P(1)–C(41)
Pt–P(2)–C(1)
Pt–P(2)–C(51)
Pt–P(2)–C(61)
C(1)–P(2)–C(51)
C(1)–P(2)–C(61)
C(51)–P(2)–C(61)
117.1(1)
114.9(1)
106.4(1)
107.4(1)
101.9(1)
107.9(2)
114.6(1)
112.7(1)
113.3(1)
105.2(1)
103.6(1)
106.6(1)
114.4(1)
113.5(1)
111.2(1)
108.3(1)
103.3(1)
105.2(1)
115.8(1)
112.4(1)
112.8(1)
103.2(1)
106.1(1)
105.6(1)
C(21)–C(1)–C(2)
C(1)–C(2)–C(3)
C(2)–C(3)–C(11)
115.3(2)
114.3(3)
114.0(3)
114.1(2)
114.1(2)
114.5(2)

98
T. Sturm et al. / Journal of Organometallic Chemistry 595 (2000) 93–101
Fig. 3. Superposition plots of (a) 1a·CHCl3 and the free ligand 1 (dashed lines), and of (b) 2a·CHCl3 and the free ligand 2 (dashed lines). Note
the significant out-of-plane bending of the Cp-bonded phosphorus in the PtCl2 complexes.
Table 4
Hydroformylations and hydromethoxycarbonylations with use of ligands 1–3
c
d
Catalyst
T (°C)
Reaction time (h)
Conversion (%)
Rc (%)
RRB (%)
e.e. (%)
a
PtCl2(1)+SnCl2
PtCl2(1)+SnCl2
PtCl2(2)+SnCl2
PtCl2(2)+SnCl2
PtCl2(2)+SnCl2
PtCl2(2)+SnCl2
PtCl2(3)+SnCl2
60
100
40
60
90
100
60
100
100
40
35
120
20
20
16
100
160
160
41
99
77
68
99
83
62
41
70
87
71
74
70
62
67
85
\99
\99
46
50
32
34
37
36
45
13
14
38 (R)
2 (S)
19 (R)
5 (R)
31 (S)
37 (S)
36 (R)
n.d.
PdCl2(PhCN)2+1 b
PdCl2(PhCN)2+2
n.d.
a Hydroformylations: p=100 bar CO/H2=1/1.
b Hydromethoxycarbonylations: p=100 bar CO.
c Chemoselectivity towards hydroformylation.
d Regioselectivity towards branched aldehyde.
cluded and hence the former explanation for the change
in the absolute configuration of the product seems to be
more appropriate.
3. Experimental
3.1. General procedures
All reactions were carried out under argon using
standard Schlenk techniques. Toluene was distilled
from sodium in the presence of benzophenone. Diethyl
ether and benzene were destilled from LiAlH4. Styrene
was freshly distilled before use.
2.4.2. Hydromethoxycarbonylations
Catalyst precursors prepared in situ from
PdCl2(PhCN)2 and either of the enantiopure ferrocenyl
ligands 1, 2 or 3 have been tested in the hydromethoxy-
carbonylation of styrene (Eq. (3)). The catalytic activity
of these systems was found to be unexpectedly low.
Acceptable conversion was only obtained after a pro-
longed reaction time of about 1 week.
NMR spectra were recorded in CDCl3 (if not other-
wise noted) on either a Bruker AM 400 WB spectrome-
ter at 400.13 MHz (1H), 100.62 MHz (13C) and 161.89
MHz (31P), or on a Varian Unity at 300 spectrometer
121.4 MHz (31P), respectively. Chemical shifts l are
reported in ppm relative to CHCl3 (7.26 and 77.00 ppm
CO/CH OH
3
PhCH=CH2ꢀꢀꢀꢀꢀꢀꢀꢀꢀꢁPhCH(CH3)COOCH3
6
10
+Ph(CH2)2COOCH3
(3)
1
for H and 13C) or relative to H3PO4 (31P). The cou-
11
In all cases both regioisomers were formed but with
pling constants in 13C-NMR spectra refer to JCP unless
the linear ester (11) being the main product.
otherwise stated. Mass spectra were measured on a

T. Sturm et al. / Journal of Organometallic Chemistry 595 (2000) 93–101
99
Finnigan 900S spectrometer (E.I., 70eV). Optical rota-
tions were measured on a Perkin–Elmer polarimeter
241 in chloroform at 20°C. Elemental analyses were
either performed at Mikroanalytisches Laboratorium
der Universita¨t Wien (Mag. J. Theiner) or were mea-
sured on a 1108 Carlo Erba apparatus.
The catalytic precursors PtCl2(PhCN)2 and PdCl2-
(PhCN)2 were prepared as described previously [23,24].
Samples of the catalytic reactions were analysed with a
Hewlett–Packard 5830A gas chromatograph fitted with
a capillary column coated with OV-1.
Anal. Calc. for C27H26F2FeNP (M=489.11): C,
66.26; H, 5.32; N, 2.86; P, 6.34. Found: C, 65.99; H,
5.19; N, 2.77; P, 6.60%.
3.3. Synthesis of (R,R)-1-bis(4-fluorophenyl)-
phosphino-2,1%-[(1-diphenylphosphino)-1,3-
propanediyl]-ferrocene (3)
To a degassed solution of 700 mg (1.43 mmol) of
(+)-aminophosphine 5 in 13 ml of freshly distilled
acetic acid was added 0.4 ml (2.3 mmol) of
diphenylphosphine. The solution was stirred for 18 h at
90°C. After cooling to r.t., the product crystallises and
is filtered off, washed with petroleum ether and dried in
vacuo giving 622 mg (0.99 mmol, 69%) of 3.
3.2. Synthesis of (R,R)-1-[bis-(4-fluorophenyl)-phos-
phino-2,1%-(1-dimethylamino)-propanediyl] ferrocene (5)
To a degassed solution of 1 g (3.72 mmol) of (S)-1,1%-
[(1-dimethylamino)-propanediyl] ferrocene, 4, in 20 ml
of ether was added dropwise 2.8 ml (4.48 mmol) of a
1.6 M solution of butyllithium in hexane at 0°C. The
reaction mixture was stirred at room temperature (r.t.)
for 4 h and then 0.8 ml (4.56 mmol) of chloro-bis-(4-
fluorophenyl)-phosphine was added at r.t. After stirring
for 16 h the mixture was hydrolysed with 30 ml of
aqueous sodium hydrogencarbonate. The organic and
the aqueous layers were separated and the aqueous
layer was extracted twice with 25 ml portions of ether.
The combined organic layers were washed with water
and dried over magnesium sulfate. After removing the
solvent under reduced pressure the product was purified
by chromatography on silica gel. Petroleum ether as the
eluent removes unpolar inpurities while a 20:80 mixture
of methanol and chloroform elutes 1.33 g (2.72 mmol,
73%) of the enantiomerically pure product.
1H-NMR: l 1.60–1.68 (m, 1H), 2.09–2.15 (m, 1H),
2.47–2.52 (m, 1H), 2.76–2.80 (m, 1H), 2.96–2.99 (m,
1H), 3.54 (s, 1H, Cp), 3.68 (s, 1H, Cp), 3.87 (s, 1H, Cp),
4.11 (s, 1H, Cp), 4.16 (s, 1H, Cp), 4.27 (s, 1H, Cp), 4.31
(s, 1H, Cp), 6.78–6.83 (m, 2H, Ph), 7.03–7.06 (m, 4H,
Ph), 7.11–7.21 (m, 5H, Ph), 7.27–7.33 (m, 3H, Ph),
7.41–7.46 (m, 2H, Ph), 7.51–7.56 (m, 2H, Ph). 13C-
NMR: l 25.15 (d, J=10.7 Hz, CH2), 37.23 (dd, J1=
3.1 Hz, J2=13.8 Hz, CH), 38.49 (dd, J1=10.0 Hz,
J2=25.2 Hz, CH2), 67.92 (Cp), 69.77 (Cp), 69.95 (Cp),
71.12 (d, J=4.6 Hz, Cp), 71.82 (Cp), 73.86 (d, J=3.8
Hz, Cp), 74.07 (d, J=14.5 Hz, q-Cp), 76.38 (dd, J1=
2.3 Hz, J2=4.6 Hz, Cp), 87.40 (q-Cp), 90.94 (dd,
J1=16.8 Hz, J2=21.4 Hz, q-Cp), 114.88 (dd, J=6.9
Hz, JCF=13.0 Hz, Ph), 114.98 (dd, J=7.7 Hz, JCF
=
12.2 Hz, Ph), 127.66 (d, J=6.9 Hz, Ph), 128.27 (d,
J=7.7 Hz, Ph), 128.31 (Ph), 128.78 (Ph), 133.45 (d,
J=19.9 Hz, Ph), 133.49 (d, J=20.7 Hz, Ph), 133.98
(q-Ph), 134.66 (dd, J=19.1 Hz, JCF=7.7 Hz, Ph),
135.70 (q-Ph), 136.56 (dd, J=22.2 Hz, JCF=7.7 Hz,
Ph), 137.09 (d, J=16.1 Hz, q-Ph), 139.73 (dd, J=20.7
Hz, JCF=3.8 Hz, q-Ph), 162.65 (d, JCF=247.1 Hz,
q-Ph), 163.23 (d, JCF=249.4 Hz, q-Ph). 31P-NMR: l
−5.34 (d, JPP=82.3 Hz); −24,09 (ddd, J1(PF)=4.2
Hz, J2(PF)=4.4 Hz, JPP=82.3 Hz). MS: m/z (rel. %):
630.4 (46.6, M+), 445.0 (100), 223.9 (44.5).
1H-NMR: l 1.81 (s, 6H), 1.83–1.91 (m, 1H), 2.37–
2.46 (m, 2H), 2.57–2.63 (m, 1H), 2.90–2.95 (m, 1H),
3.63 (m, 1H, Cp), 3.70 (m, 1H, Cp), 3.86 (m, 1H, Cp),
4.08 (m, 1H, Cp), 4.14 (m, H, Cp), 4.18 (m, 1H, Cp),
4.31 (m, 1H, Cp), 6.91–7.02 (m, 4H, Ph), 7.26–7.32 (m,
2H, Ph), 7.36–7.41 (m, 2H, Ph). 13C-NMR: l 25.47
(CH2), 38.27 (d, J=9.9 Hz, CH2), 44.24 (CH3), 66.44
(d, J=1.5 Hz, CH), 67.75 (CH), 69.31 (CH), 70.13
(CH), 71.42 (d, J=6.1 Hz, CH), 71.58 (CH), 73.55 (d,
J=4.6 Hz, CH), 74.39 (d, J=4.6 Hz, CH), 75.53 (d,
J=12.2 Hz, q-C), 88.68 (q-C), 114.74 (dd, J=6.9 Hz,
[h]20 (°, u) +165.5 (589), +167.5 (578), +162.7
(546); c=1.024.
Anal. Calc. for C37H30F2FeP2 (M=630.11): C, 70.48;
H, 4.76; P, 9.84. Found: C, 69.74; H, 4.78; P, 9.95%.
JCF=13.0 Hz, Ph), 114.95 (dd, J=6.9 Hz, JCF=13.0
Hz, Ph), 134.15 (d, J=13.0 Hz, q-Ph), 134.89 (dd,
J=8.4 Hz, JCF=3.1 Hz, q-Ph), 135.15 (dd, J=21.4
Hz, JCF=7.7 Hz, Ph), 135.76 (dd, J=21.4 Hz, JCF
=
3.4. Synthesis of PtCl2(1), (1a), PtCl2(2), (2a) and
PtCl2(3), (3a)
8.4 Hz, Ph), 162.84 (d, JCF=247.0 Hz, q-Ph), 163.00
(d, JCF=248.6 Hz, q-Ph). 31P-NMR: l −23.02 (dd,
J
1,PF=J2,PF=4.0 Hz).
MS: m/e (rel. %) 489.0 (33.4, M+), 474.0 (24.0),
A degassed solution of 46.7 mg (0.099 mmol) of
dibenzonitrilo platinum(II)chloride in 6 ml of benzene
was heated to 80–90°C for about 5 min. To this
solution was added a degassed solution of 0.1 mmol
diphosphine. The reaction mixture was refluxed for 1 h
446.0 (30.9), 294.1 (32.4), 264.9 (30.8), 251.0 (100),
237.0 (59.4), 211.1 (25.6), 149.0 (32.4).
[h]20 (°, u) +177.5 (589), +177.2 (578), +156.4°
(546); c=0.994.

100
T. Sturm et al. / Journal of Organometallic Chemistry 595 (2000) 93–101
and then stirred at r.t. for another 16 h. The precipi-
tated product was washed with benzene and hexane and
dried in vacuum. Yields were in the range of 80–90%
for all three complexes.
Ph), 131.43 (d, J=3.1 Hz, Ph), 131.62 (d, J=70.4 Hz,
q-Ph), 133.09 (d, J=71.9 Hz, q-Ph), 133.66 (d, J=9.2
Hz, Ph), 136.66 (bs, Ph). 31P-NMR: see Table 1.
[h]20 (°, l) +35.8 (589), +25.3 (578), −43.5 (546);
c=0.495.
3.4.1. Compound 1a
Yield: 88%; H-NMR: l 1.54–1.57 (m, 1H), 2.19 (s,
Anal. Calc. for C37H44Cl2FeP2Pt (M=872.55): C,
50.93; H, 5.08. Found: C, 51.11; H, 5.33%.
1
1H, Cp), 2.26–2.35 (m, 2H), 2.52–2.56 (m, 1H), 2.77–
2.85 (m, 1H), 3.52 (m, 1H, Cp), 3.78 (m, 1H, Cp), 3.96
(m, 1H, Cp), 4.04 (m, 1H, Cp), 4.11 (m, 1H, Cp), 4.41
(m, 1H, Cp), 6.79–6.85 (m, 2H, Ph), 7.02–7.07 (m, 2H,
Ph), 7.18–7.24 (m, 1H, Ph), 7.34–7.43 (m, 5H, Ph),
7.48–7.50 (m, 1H, Ph), 7.54–7.57 (m, 3H, Ph), 7.73–
7.78 (m, 2H, Ph), 8.10–8.15 (m, 2H, Ph), 8.27 (bs, 2H,
Ph). 13C-NMR: l 23.78 (d, J=13.8 Hz, CH2), 32.51 (d,
J=37.5 Hz, CH), 41.01 (d, J=10.7 Hz, CH2), 69.05
(Cp), 69.09 (d, J=7.7 Hz, Cp), 71.78 (Cp), 72.02 (Cp),
72.35 (Cp), 72.61 (dd, J1=3.8 Hz, J2=8.4 Hz, Cp),
75.63 (d, J=5.4 Hz, Cp), 87.06 (q-Cp), 89.98 (d, J=
15.3 Hz, q-Cp), 126.75 (d, J=61.2 Hz, q-Ph), 127.39
(d, J=11.5 Hz, Ph), 127.66 (d, J=11.5 Hz, Ph), 127.83
(d, J=12.2 Hz, Ph), 128.54 (d, J=10.7 Hz, Ph), 129.44
(d, J=60.4 Hz, q-Ph), 129.97 (d, J=3.1 Hz, Ph),
131.09 (d, J=3.1 Hz), 131.13 (d, J=71.9 Hz, q-Ph),
131.59 (d, J=3.1 Hz, Ph), 131.69 (d, J=3.1 Hz, Ph),
133.10 (d, J=10.0 Hz, Ph), 33.39 (d, J=68.8 Hz,
q-Ph), 134.25 (d, J=10.6 Hz, Ph), 135.25 (d, J=10.7
Hz, Ph), 136.41 (d, J=10.7 Hz, Ph). 31P-NMR: see
Table 1.
3.4.3. Compound 3a
Yield: 83%. H-NMR: l 1.53–1.61 (m, 1H), 2.23–
1
2.29 (m, 1H), 2.34 (s, 1H, Cp), 2.34–2.39 (m, 1H),
2.54–2.57 (m, 1H), 2.77–2.85 (m, 1H), 3.55 (m, 1H,
Cp), 3.83 (m, 1H, Cp), 4.00 (m, 1H, Cp), 4.02 (m, 1H,
Cp), 4.15 (m, 1H, Cp), 4.44 (m, 1H, Cp), 6.74–6.78 (m,
4H, Ph), 7.24–7.29 (m, 2H, Ph), 7.34–7.45 (m, 5H, Ph),
7.47–7.51 (m, 1H, Ph), 7.70–7.75 (m, 2H, Ph), 8.07–
8.12 (m, 2H, Ph), 8.27 (bs, 2H, Ph). 31P-NMR (CDCl3,
161.9 MHz, H3PO4): see Table 1.
Anal. Calc. for C37H30Cl2F2FeP2Pt (M=896.42): C,
49.58; H, 3.37. Found: C, 49.75; H, 3.52%.
3.5. Hydroformylation experiments with 1a, 2a and 3a
In a typical experiment a solution of 0.025 mmol of
PtCl2(2) and 0.05 mmol of SnCl2 in 30 ml of toluene
containing 0.1 mol of styrene was transferred under
argon into a 150 ml stainless steel autoclave. The
reaction vessel was pressurised to 80 bar total pressure
(1:1 CO–H2) and the magnetically stirred mixture was
heated in an oil bath. The pressure was monitored
throughout the reaction. After cooling and venting of
the autoclave, the pale yellow solution was immediately
analysed by GC, then fractionally distilled. Finally, the
specific rotation of the 2-phenylpropanal fraction was
determined.
[h]20 (°, u) +9.6 (589), +3.3 (578), −44.3 (546);
c=0.519.
Anal. Calc. for C37H32Cl2FeP2Pt (M=860.44): C,
51.65; H, 3.75. Found: C, 51.94; H, 4.02%.
3.4.2. Compound 2a
1
Yield: 84%. H-NMR: l 0.95–1.81 (m, 18H), 1.85 (s,
1H, Cp), 1.85–1.92 (m, 2H), 1.99–2.05 (m, 1H), 2.11–
2.13 (m, 1H), 2.23–2.28 (m, 1H), 2.37 (m, 1H), 2.47–
2.51 (m, 1H), 2.59–2.61 (m, 1H), 2.69–2.78 (m, 1H),
3.63 (s, 1H, Cp), 3.76 (s, 1H, Cp), 3.88 (s, 1H, Cp), 4.15
(s, 2H, Cp), 4.32 (s, 1H, Cp), 7.13–7.15 (m, 3H, Ph),
7.17–7.26 (m, 2H, Ph), 7.40–7.44 (m, 3H, Ph), 8.06–
8.13 (m, 2H, Ph).
3.6. Hydromethoxycarbonylation experiments
In a typical experiment a 150 ml stainless steel auto-
clave was charged under argon with 0.04 mmol of
PdCl2(PhCN)2, 0.02 mmol of 2, with 1.8 ml of styrene,
10 ml of toluene and 5 ml of methanol. The reaction
vessel was pressurised with CO to 130 bar and the
magnetically stirred mixture was heated in an oil bath.
The pressure was monitored throughout the reaction.
After cooling and venting of the autoclave, the dark red
solution was immediately analysed by GC.
13C-NMR: l 23.87 (d, J=11.5 Hz, CH2), 25.85
(CH2), 26.36 (CH2), 27.07 (d, J=13.0 Hz, CH2), 27.20
(d, J=11.5 Hz, CH2), 27.58 (d, J=11.5 Hz, CH2),
27.79 (d, J=13.0 Hz, CH2), 28.59 (dd, J1=2.3 Hz,
J2=29.8 Hz, CH), 29.75 (d, J=3.8 Hz, CH2), 30.07 (d,
J=2.3 Hz, CH2), 31.01 (CH2), 31.41 (CH2), 36.19 (d,
J=30.6 Hz, CH), 38.58 (d, J=1.4 Hz, CH), 40.69 (d,
J=5.4 Hz, CH2), 68.76 (d, J=8.4 Hz, Cp), 68.90 (dd,
J1=2.3 Hz, J2=63.5 Hz, q-C), 69.03 (Cp), 71.27 (Cp),
71.87 (Cp), 72.39 (dd, J1=3.8 Hz, J2=7.7 Hz, Cp),
73.17 (Cp), 76.48 (d, J=5.4 Hz, Cp) 85.90 (q-Cp),
90.68 (d, J=18.4 Hz, q-Cp), 127.33 (d, J=18.4 Hz,
Ph), 127.66 (d, J=11.5 Hz, Ph), 130.09 (d, J=2.3 Hz,
3.7. X-ray structure determinations of 1a·CHCl3 and
2a·CHCl3
Crystal data and experimental details are given in
Table 2. X-ray data for 1a·CHCl3 and 2a·CHCl3 were
collected on a Siemens Smart CCD area detector dif-

T. Sturm et al. / Journal of Organometallic Chemistry 595 (2000) 93–101
101
[2] B. Cornils, in: J. Falbe (Ed.), New Synthesis with Carbon
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fractometer (graphite monochromated Mo–Ka radia-
,
tion, u=0.71073 A, a nominal crystal-to-detector dis-
tance of 44.5 mm, 4×606 0.3°-ꢀ-scan frames covering
the complete reciprocal space up to qmax=30°). Correc-
tions for Lorentz and polarization effects, for crystal
decay, and for absorption were applied. All structures
were solved by direct methods using the program
SHELXS-97 [25]. Structure refinement on F2 was carried
out with program SHELXL-97 [26]. Non-hydrogen
atoms were refined anisotropically. Hydrogen atoms
were inserted in idealized positions and were refined
riding with the atoms to which they were bonded.
[7] H. Brunner, W. Zettlmeier, Handbook of Enantioselective Catal-
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4. Supplementary material
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(1991) 2046.
Crystallographic data (excluding structure factors)
for the structure reported in this paper have been
deposited with the Cambridge Crystallographic Data
Centre, CCDC nos. 118736, 118737. Copies of this
information may be obtained free of charge from The
Director, CCDC, 12 Union Road, Cambridge, CB2
1EZ, UK (Fax: +44-1223-336033; e-mail: de-
posit@ccdc.cam.ac.uk or www: http://www.ccdc.
cam.ac.uk).
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Organomet. Chem. 508 (1996) 209.
[22] T. Sturm, Ph.D. Thesis, University of Vienna, Austria, 1999.
[23] F.R. Hartley, Organomet. Chem. Rev. A 6 (1970) 119.
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3178.
Acknowledgements
The authors thank the Hungarian National Science
Foundation and Stiftung Aktion Osterreich-Ungarn for
financial support (grants OTKA T023525 and 26U2,
8
8
34OU2 respectively).
References
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Structures, University of Go¨ttingen, Germany, 1997.
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Refinement, University of Go¨ttingen, Germany, 1997.
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