Nonsymmetric palladium complexes of partly fluorinated bisphosphine ligands: Efficient catalysts for flexible propene/CO copolymer materials of ultrahigh molecular weight

Article abstract of DOI:10.1021/om0302138

Five new nonsymmetric 1-diphenylphosphino-3-{bis[aryl]phosphino}propane ligands 1b-f [aryl: b = 3,5-bis(trifluoromethyl)phenyl, c = 3,5-dimethylphenyl, d = 3,5-difluorophenyl, e = 2-(trifluoromethyl)phenyl, f = 2,4,6-trifluorophenyl] and their corresponding neutral dichloro palladium(II) 2b-f, diiodo palladium(II) 3d,e, and dicationic diacetonitrile palladium(II) ditetrafluoroborate complexes 4b-f were synthesized. The symmetric ligand 1,3-bis{bis[3,5-bis(trifluoromethyl)phenyl]phosphino}propane (1a) and the related palladium(II) complexes 2a and 4a were prepared for comparison. Solid state structures of new ligands were determined by X-ray structure analysis in the form of the dichloro (2a-c,f) and diiodo (3d,e) compounds. The properties of the symmetric (4a) and nonsymmetric catalysts (4b-f) were tested in propene/CO copolymerization experiments. A clear correlation between primarily steric effects of these ligands and the catalyst activity as well as the molecular weight of the resulting polyketone materials was observed. The nonsymmetric structure 4b, bearing CF₃ groups in the 3,5-position of two aryl units on one phosphorus side, proved to be the most effective catalyst, which reached an activity maximum (12.7 kg[mol(Pd) × h]^-1) and led at the same time to propene/CO copolymers of high molecular weight (M_w ≈ 5 × 10⁵ g mol^-1). The same catalyst species 4b affords even ultrahigh molecular weight ethene/propene/CO terpolymers with M_w ≈ 8 × 10⁵ g mol^-1. These novel polyketones possess a predominantly regioirregular microstructure, leading to interesting flexible material properties in contrast to already known regioregular and thereby brittle propene/CO copolymers.

Full text of DOI:10.1021/om0302138

Organometallics 2003, 22, 3905-3914
3905
Non sym m etr ic P a lla d iu m Com p lexes of P a r tly
F lu or in a ted Bisp h osp h in e Liga n d s: Efficien t Ca ta lysts
for F lexible P r op en e/CO Cop olym er Ma ter ia ls of
Ultr a h igh Molecu la r Weigh t
Uwe W. Meier,† Frank Hollmann,† Ulf Thewalt,‡ Martti Klinga,§
Markku Leskela¨,§ and Bernhard Rieger*,†
Department for Materials and Catalysis, University of Ulm, D-89069 Ulm, Germany,
Sektion Ro¨ntgen- und Elektronenbeugung, University of Ulm, D-89069 Ulm, Germany, and
Department of Chemistry, University of Helsinki, FIN-00014 Helsinki, Finland
Received March 19, 2003
Five new nonsymmetric 1-diphenylphosphino-3-{bis[aryl]phosphino}propane ligands 1b-f
[aryl: b ) 3,5-bis(trifluoromethyl)phenyl, c ) 3,5-dimethylphenyl, d ) 3,5-difluorophenyl,
e ) 2-(trifluoromethyl)phenyl, f ) 2,4,6-trifluorophenyl] and their corresponding neutral
dichloro palladium(II) 2b-f, diiodo palladium(II) 3d ,e, and dicationic diacetonitrile palla-
dium(II) ditetrafluoroborate complexes 4b-f were synthesized. The symmetric ligand 1,3-
bis{bis[3,5-bis(trifluoromethyl)phenyl]phosphino}propane (1a ) and the related palladium(II)
complexes 2a and 4a were prepared for comparison. Solid state structures of new ligands
were determined by X-ray structure analysis in the form of the dichloro (2a -c,f) and diiodo
(3d ,e) compounds. The properties of the symmetric (4a ) and nonsymmetric catalysts (4b-f)
were tested in propene/CO copolymerization experiments. A clear correlation between
primarily steric effects of these ligands and the catalyst activity as well as the molecular
weight of the resulting polyketone materials was observed. The nonsymmetric structure
4b, bearing CF3 groups in the 3,5-position of two aryl units on one phosphorus side, proved
to be the most effective catalyst, which reached an activity maximum (12.7 kg[mol(Pd) ×
h]-1) and led at the same time to propene/CO copolymers of high molecular weight (Mh w ≈ 5
× 105 g mol-1). The same catalyst species 4b affords even ultrahigh molecular weight ethene/
propene/CO terpolymers with Mh w ≈ 8 × 105 g mol-1. These novel polyketones possess a
predominantly regioirregular microstructure, leading to interesting flexible material proper-
ties in contrast to already known regioregular and thereby brittle propene/CO copolymers.
In tr od u ction
ficient activity of the applied (dppp)Pd(II) catalysts5
prompted us to look for other catalyst lead structures.
We report here on a series of new nonsymmetric bis-
phosphine ligands bearing partially fluorinated aro-
matic substituents at one of the phosphorus moieties,
on the corresponding palladium(II) complexes, and on
their polymerization performance (Chart 1).6,7 This
structural motif of partly fluoro-substituted, nonsym-
metric complexes allows the combination of a superior
The metal-catalyzed copolymerization of olefins with
polar monomers is still an attractive field to create new
materials from simple technical monomers. In particu-
lar, the highly crystalline ethene/CO copolymers rep-
resent an established and well-investigated class of such
polar structures.1,2 We recently opened a route to regio-
and stereoirregular and hence elastic propene/CO co-
and propene/ethene/CO terpolymers of increased mo-
lecular weight thatsbesides new material propertiess
offer a chance for improved processability, due to re-
duced melting transitions.3,4 Nevertheless, the insuf-
(4) This approach was taken up by other groups that used Consiglio’s
concept of alkyl-substituted bisphosphine ligands to produce propene/
CO copolymers of relatively high molecular weight by comprising a
regioregular microstructure that leads to brittle polymers. (a) Lindner,
E.; Schmid, M.; Wald, J .; Queisser, J . A.; Gepra¨gs, M.; Wegner, P.;
Nachtigal, C. J . Organomet. Chem. 2000, 602, 173. (b) Batistini, A.;
Consiglio, G.; Suter, U. Angew. Chem., Int. Ed. Engl. 1992, 31, 303.
(c) Barsacchi, M.; Batistini, A.; Consiglio, G.; Suter, U. W. Macromol-
ecules 1992, 25, 3604.
† Department for Materials and Catalysis, University of Ulm.
‡ Sektion Ro¨ntgen- und Elektronenbeugung, University of Ulm.
§ University of Helsinki.
(1) (a) Eur. Plast. News 1995, Oct, 57. (b) Shell, Carilon Thermo-
plastic Polymers, Information Sheet, 1994.
(5) dppp: 1,3-bis(diphenylphosphino)propane.
(2) For recent reviews see: (a) Bianchini, C.; Meli, A. Coord. Chem.
Rev. 2002, 225 (1-2), 35. (b) Ittel, S. D.; J ohnson, L. K.; Brookhart,
M. Chem. Rev. 2000, 100, 1169. (c) Britovsek, G. J . P.; Gibson, V. C.;
Wass, D. Angew. Chem., Int. Ed. 2000, 38, 428. (d) Drent, E.;
Budzelaar, P. H. M. Chem. Rev. 1996, 96, 663. (e) Cavell, K. J . Coord.
Chem. Rev. 1996, 155, 209.
(3) (a) Mu¨cke, A.; Rieger, B. Macromolecules 2002, 35, 2865. (b)
Huhn, W.; Hollmann, F.; Hild, S.; Kriewall, T.; Rieger, B. Macromol.
Mater. Eng. 2000, 283, 115.
(6) For reports on nonsymmetric catalysts in 1-olefin/CO copolym-
erization reactions see: (a) Gambs, C.; Chaloupka, S.; Consiglio, G.;
Togni, A. Angew. Chem. 2000, 112, 2602; Angew. Chem., Int. Ed. 2000,
39, 2486. (b) Nozaki, K.; Hiyama, T. Organometallics 2000, 19, 2031.
(c) Nozaki, K.; Sato, N.; Tonomura, Y.; Yasutomi, M.; Takaya, H.;
Hiyama, T.; Matsubara, T.; Koga, N. J . Am. Chem. Soc. 1997, 119,
12779. (d) Keim, W.; Mass, H. J . Organomet. Chem. 1996, 514, 271.
(e) Van Leeuwen, P. W. N. M.; Roobeek, C. F.; van der Heijden, H. J .
Am. Chem. Soc. 1994, 116, 12117.
10.1021/om0302138 CCC: $25.00 © 2003 American Chemical Society
Publication on Web 08/09/2003

3906 Organometallics, Vol. 22, No. 19, 2003
Meier et al.
Ch a r t 1. Novel Non sym m etr ic Bisp h osp h in e
P d (II) Com p lexes
(II) compounds (3d ,e) by treatment with NaI in DMSO
to achieve better solubility and crystallization proper-
ties. The dicationic complexes 4a -f were obtained from
2a -d ,f and 3e by halide abstraction using AgBF4 in
acetonitrile.
Solid Sta te Str u ctu r es. Single crystals of the dichlo-
ro (2a -c,f) and diiodo complexes (3d ,e), grown from
solvent mixtures (cf. Experimental Section), were char-
acterized by X-ray structure analysis. The crystal-
lographic results of 2a ,b,f and 3e are depicted in Figures
1-4 and Table 1, and the data of 2c and 3d are
summarized in the Supporting Information.
The gross coordination geometry around the Pd(II)
centers in all investigated solid state structures is nearly
ideal square-planar, independent of the particular
substitution of the chelating bisphosphine ligand and
of the halide atoms (Cl: 2a -c,f; I: 3d ,e). The structures
of the symmetric complex 2a and the nonsymmetric
complex 2b indicate the bulkiness of the CF3-substituted
phenyl groups, which afford a parallel orientation of
axial phenyl rings. This leads in the case of 2a to a
shielding of the Pd(II) center (cf. polymerization experi-
ments). The bond angles P-Pd-Hal range from 86.03
(8)° to 90.31(3)° at the PPh2 side and from 86.60(4)° to
92.39(11)° at the PAr2 moiety (Table 2).13-15 However,
no clear correlation of angles, bond lengths, and the
particular aryl substitution of the complexes can be
found. There is no indication that number or position
of CF3, CH3, and F substituents in the complexes
2a -c,f and 3d influence bond lengths and bond angles
in a predictable manner. Only in the case of 3e are the
P-Pd-I angle (92.39(11)°) and the Pd-P bond length
(2.310(4) Å) at the ortho-CF3-substituted part increased
compared to the corresponding values at the phenyl side
(87.93(11)°; 2.276(4) Å), resulting from repulsive effects
of these bulky ortho-substituents. The same argument
can be used to explain the splitting of 1H and 19F NMR
signals in the Pd(II) complexes of ligand 1e, as free
rotation of the aryl fragments is restricted.
Complexes 2a -c and 3d were found in the solid state
to exist in a chair conformation formed by the six-
membered metallacycles. This implies that the two
aromatic substituents on one side of the P1-Pd-P2
plane are both oriented either in an axial or in an
equatorial direction. Complexes 2f and 3e show a twist
conformation of the metallacycles, affording an axial/
equatorial orientation of the phenyl groups attached to
the phosphorus atoms. However, we have no evidence
that the different bridge arrangements are present in
solution as well. The 31P NMR spectra give just one
signal for 2a and two resonances for the nonsymmetric
complexes, as expected for systems with highly flexible
bridge conformations.
catalyst activity with unexpectedly high product mo-
lecular weights and interesting properties of the flexible
polyketone materials, due to a variable regioregularity
of their microstructure.
Resu lts a n d Discu ssion
Liga n d a n d Com p lex Syn th esis. The symmetric
bisphosphine 1a is accessible by treatment of the
deprotonated secondary phosphine 5 with 0.5 equiv of
1,3-dibromopropane (Scheme 1A). Nonsymmetric pro-
pyl-bridged bisphosphines are accessible by the reaction
of secondary phosphides with 3-chloropropyl diarylphos-
phines.8 In a modified procedure ligand 1b was obtained
in high yield and purity by deprotonation of the CF3-
substituted compound 5 with KOH in DMSO,9 followed
by addition of the alkyl chloride 6.10
This strategy is not suitable for the preparation of
nonsymmetric bisphosphines containing ring-fluori-
nated phenyl groups (e.g., Scheme 1B, 1d ,f), as the
phosphide anion attacks the aryl-fluorine bond. There-
fore, phenyl(3-phosphinopropyl)phosphine (8) (from 7 by
reduction with LiAlH411) was treated with 2 equiv of
Br2,12 resulting in the hydrobromide 9, which affords
after deprotonation and substitution with the fluori-
nated Grignard reagents the desired ligands 1c-f.
The dichloro palladium(II) complexes 2a -f were
prepared by reaction of the corresponding bisphosphines
(1a -f) with (COD)PdCl2 in CH2Cl2 (Scheme 2). Com-
plexes 2d ,e were converted into the diiodo palladium-
(7) For reports on nonsymmetric complexes in catalysis see: (a)
Casey, P. C.; Paulsen, E. L.; Beuttenmueller, E. W.; Proft, B. R.; Matter,
B. A.; Powell, D. R. J . Am. Chem. Soc. 1999, 121, 63. (b) RajanBabu,
T. V.; Casalnuovo, A. L. J . Am. Chem. Soc. 1996, 118, 6325. (c) Nozaki,
K.; Li, W.; Horiuchi, T.; Takaya, H.; Saito, T.; Yoshida, A.; Matsumara,
K.; Kato, Y.; Imai, T.; Miura, T.; Kumobayashi, H. J . Org. Chem. 1996,
61, 7658. (d) Sakai, N.; Mano, S.; Nozaki, K.; Takaya, H. J . Am. Chem.
Soc. 1993, 115, 7033.
(8) (a) Renaud, E.; Russell, R. B.; Fortier, S.; Brown, S. J .; Baird,
M. C. J . Organomet. Chem. 1991, 419, 403. (b) Arpac, E.; Dahlenburg,
L. Z. Naturforsch. 1980, 35b, 146. (c) Grim, S. O.; Barth, R. C. J .
Organomet. Chem. 1975, 94, 327.
(9) For deprotonation of sec. phosphines in DMSO with KOH see:
(a) Tsvetkov, E. N.; Bondarenko, N. A.; Malakhova, I. G.; Kabachnik,
M. I. Synthesis 1986, 3, 198. (b) Tsvetkov, E. N.; Bondarenko, N. A.;
Malakhova, I. G.; Kabachnik, M. I. J . Gen. Chem. USSR (Engl. Transl.)
1985, 55 (1), 8.
(10) For the synthesis of 1b via radical-induced addition of secondary
phosphines and allylphosphines see Supporting Information.
(11) For similar reactions see: Baacke, M.; Hietkamp, S.; Morton,
S.; Stelzer, O. Chem. Ber. 1981, 114, 2568.
P r op en e/CO Co- a n d Ter p olym er iza tion Exp er i-
m en t s. All copolymerization experiments were per-
(13) The bond lengths and angles around the Pd(II) ion of all
investigated complexes (Table 2) are similar to corresponding literature-
known values in related phenyl-substituted bisphosphine dihalide Pd-
(II) compounds. (dppp)PdCl2 (cf. ref 14): Pd-P (2.244(1)/2.249(2) Å);
Pd-Cl (2.351(1)/2.358(2) Å). The bond angles P-Pd-P (90.58(5)°) and
Cl-Pd-Cl (90.78(5)°) resemble those found in our study. The values
of the diiodo complexes 3d ,e resemble those of [1,2-bis(diphenylphos-
phino)ethane]PdI2 (cf. ref 15): Pd-P (2.2608(14)/2.2756(12) Å); Pd-I
bond lengths (2.6649(8)/2.6446(10) Å).
(14) Steffen, W. L.; Palenik G. J . Inorg. Chem. 1976, 15, 2432.
(15) Oberhauser, W.; Bachmann, C.; Stampfl, T.; Haid, R.; Bru¨geller,
P. Polyhedron 1997, 16, 2827.
(12) For similar reactions see: Goerlich, J . R.; Weiss, J .-V.; J ones,
P. G.; Schmutzler, R. Phosphorus, Sulfur Silicon 1992, 66, 223.

Nonsymmetric Palladium Complexes
Organometallics, Vol. 22, No. 19, 2003 3907
Sch em e 1. Syn th esis of th e Sym m etr ic (1a ) a n d Non sym m etr ic Bisp h osp h in e Liga n d s (1b-f)
Sch em e 2. P r ep a r a tion of th e Neu tr a l (2a -f, 3d ,e) a n d Dica tion ic P d (II) Com p lexes (4a -f)
formed in a 250 mL steel autoclave. The catalyst pre-
cursor complexes 4a -g (4g: [(CH3CN)2dpppPd](BF4)2)
were dissolved in dichloromethane and activated by
adding an optimized amount of methanol.16,17 The
polydispersities of all copolymer products are in the
range Mh w/ Mh n ) 1.4-1.8, indicating the homogeneity of
the copolymerization reactions (Table 3). All experi-
ments have been performed at least twice to ensure

3908 Organometallics, Vol. 22, No. 19, 2003
Meier et al.
F igu r e 1. ORTEP plot and atom-labeling scheme of
complex 2a . Thermal ellipsoids are depicted at the 50%
probability level. Hydrogen atoms, THF molecules, and
second independent complex molecule are omitted.
F igu r e 4. ORTEP plot and atom-labeling scheme of
complex 2f. Thermal ellipsoids are depicted at the 50%
probability level. Hydrogen atoms and DMSO molecules
are omitted.
about Mh w ) 1.6 × 105 g mol-1 (Table 3, entry 7).18 To
screen the influence of bulky, electron-withdrawing
substituents on the aromatic fragments of the basic
dppp ligand system, all four phenyl groups were ex-
changed in a first approach by 3,5-bis(trifluoromethyl)-
phenyl units, leading to the symmetric complex 4a ,
bearing eight CF3 groups in all meta-positions of the
phenyl rings. Polymerization experiments, however,
revealed that this catalyst is obviously sterically over-
crowded, so that the activity (≈ 0.5 of the dppp catalyst
4g) andsas a consequencesalso the molecular weight
of the polymer product are considerably reduced (Mh w
)
1.0 × 105 g mol-1).
This situation changed completely when the nonsym-
metric complex 4b, bearing four m-CF3 substituents on
only one ligand side, was applied (Figure 5). Most
interestingly, 4b leads to significantly increased activity
(Table 3, entry 2), reaching values up to about 13 kg
[mol(Pd) × h]-1. In addition, 4b gives the highest
molecular weight propene/CO copolymers (Mh w ≈ 5 × 105
g mol-1) that still shows flexible material properties,19
due to the just slightly enriched regioregularity relative
to the dppp catalyst 4g (H-T; 4g: 56%, 4b: 71%; Table
3). This success prompted us to look into ethene/
propene/CO terpolymerization experiments using our
recently developed “pulse feed polymerization tech-
nique” (PFP)3b comprising the pulsewise addition of the
faster ethene monomer to a running propene/CO copo-
lymerization experiment. This protocol simulates a low,
nonconstant C2 concentration during the entire polym-
erization period affording new, soluble C2/C3/CO-ter-
polymers with high C2 content. The molecular weight
F igu r e 2. ORTEP plot and atom-labeling scheme of
complex 2b. Thermal ellipsoids are depicted at the 50%
probability level. Hydrogen atoms are omitted.
(16) Abu-Surrah, A. S.; Wursche, R.; Eckert, G.; Pechold, W.; Rieger,
B. Macromolecules 1996, 29, 4806.
F igu r e 3. ORTEP plot and atom-labeling scheme of
complex 3e. Thermal ellipsoids are depicted at the 50%
probability level. Hydrogen atoms and CHCl3 molecules are
omitted.
(17) The actual concentration of catalytically active bisphosphine
Pd(II) units was determined by adding a defined amount of inert
standard (diphenylmethylphosphineoxide) to 31P NMR samples of the
catalyst precursors 4a -g. The ratio of the 31P signals from phosphi-
neoxide to P resonances of the complex delivers the desired concentra-
tion values (error ( 5%).
(18) Abu-Surrah, A. S.; Rieger, B. Top. Catal. 1999, 7, 165.
(19) Detailed analysis of material properties will be published
elsewhere.
reproducibility. We used the dppp complex 4g as refer-
ence catalyst, which gave regioirregular propene/CO
copolymers with medium to high molecular weights of

Nonsymmetric Palladium Complexes
Organometallics, Vol. 22, No. 19, 2003 3909
Ta ble 1. Su m m a r y of Cr ysta l Da ta a n d Str u ctu r e Refin em en t P a r a m eter s for 2a , 2b, 3e, a n d 2f
2a ‚1.5THF
2b
3e‚2CHCl3
2f‚DMSO
empirical formula
fw
C
41H30Cl2F24O1.5P2Pd
C31H22Cl2F12P2Pd
861.73
C31H26Cl6F6I2P2Pd
1147.36
C29H26Cl2F6OP2PdS
775.80
1241.89
cryst color and shape
colorless prism
0.50 × 0.25 × 0.07
triclinic
colorless prism
0.37 × 0.34 × 0.15
monoclinic
P21
13.626(2)
8.655(1)
13.946(2)
90
90.56(1)
red needle fragment
0.40 × 0.26 × 0.15
monoclinic
P21/n
11.509(2)
15.023(2)
23.074(5)
90
102.92(2)
90
yellow prism
0.24 × 0.22 × 0.15
monoclinic
P21/n
12.377(3)
17.507(3)
14.526(3)
90
95.72(3)
90
3132.1(11)
4
1.645
cryst size, mm
cryst syst
space group
a, Å
b, Å
c, Å
P1h
15.591(4)
27.100(8)
12.828(3)
101.92(2)
90.37(2)
R, deg
â, deg
γ, deg
77.52(2)
5174(2)
4
90
V, Å3
1644.7(3)
2
1.740
3888.5(13)
4
1.960
Z
D
calcd., g/cm3
1.594
T, K
193
0.643
2456
173
0.915
852
173
2.612
2200
223
0.991
1552
abs coeff, mm-1
F(000)
θ range, deg
2.57-24.00
0 e h e 17
-30 e k e 31
-14 e l e 14
14 728
2.77-25.98
-16 e h e 16
-10 e k e 10
-17 e l e 17
19 316
2.20-24.00
-13 e h e 13
-17 e k e 16
-26 e l e 26
24 182
2.02-25.92
-15 e h e 15
-19 e k e 19
-17 e l e 17
24 200
index range
no. of reflns collected
no. of unique reflns
14 178 [R(int) ) 0.0363]
1.036
6184 [R(int) ) 0.0365]
1.008
6030 [R(int) ) 0.0526]
1.255
5749 [R(int) ) 0.0442]
0.999
goodness-of-fit on F2
final R indices [I > 2σ(I)]
R1 ) 0.0759
wR2 ) 0.1745
R1 ) 0.1022
wR2 ) 0.1908
0.888 and -0.738
R1 ) 0.0247
wR2 ) 0.0649
R1 ) 0.0259
wR2 ) 0.0654
0.665 and -0.404
R1 ) 0.0854
wR2 ) 0.2018
R1 ) 0.0961
wR2 ) 0.2058
2.586 and -1.754
R1 ) 0.0296
wR2 ) 0.0638
R1 ) 0.0446
wR2 ) 0.0667
1.002 and -0.511
R indices (all data)
largest diff peak and hole, e/Å3
Ta ble 2. Selected Bon d Dista n ces (Å) a n d An gles (d eg) for 2a , 2b, 3e, a n d 2f
2b 3e
2a
2f
Bond Lengths
Pd(1)-P(1)
Pd(1)-P(2)
Pd(1)-Cl(1)
Pd(1)-Cl(2)
P(1)-C(1)
2.235(2)
2.243(2)
2.338(2)
2.321(2)
1.822(7)
1.802(8)
Pd-P(1)
Pd-P(2)
Pd-Cl(1)
Pd-Cl(2)
P(1)-C(1)
P(2)-C(3)
2.253(1)
Pd(1)-I(1)
Pd(1)-I(2)
Pd(1)-P(1)
Pd(1)-P(2)
P(1)-C(1)
P(2)-C(3)
2.641(2)
2.631(2)
2.276(4)
2.310(4)
1.844(16)
1.842(15)
Pd-P(1)
Pd-P(2)
Pd-Cl(1)
Pd-Cl(2)
P(1)-C(1)
P(2)-C(3)
2.233(1)
2.247(1)
2.357(1)
2.355(1)
1.831(3)
1.834(3)
2.263(1)
2.359(1)
2.347(1)
1.817(3)
1.825(3)
P(2)-C(3)
Bond Angles
P(1)-Pd(1)-P(2)
Cl(1)-Pd(1)-Cl(2)
P(1)-Pd(1)-Cl(1)
P(1)-Pd(1)-Cl(2)
P(2)-Pd(1)-Cl(2)
P(2)-Pd(1)-Cl(1)
93.52(8)
91.57(8)
86.03(8)
175.85(9)
88.52(8)
174.27(10)
P(1)-Pd-P(2)
Cl(1)-Pd-Cl(2)
P(1)-Pd-Cl(1)
P(1)-Pd-Cl(2)
P(2)-Pd-Cl(2)
P(2)-Pd-Cl(1)
89.49(3)
90.27(3)
89.55(3)
176.20(4)
90.31(3)
174.23(4)
P(1)-Pd(1)-P(2)
I(1)-Pd(1)-I(2)
P(1)-Pd(1)-I(1)
P(1)-Pd(1)-I(2)
P(2)-Pd(1)-I(2)
P(2)-Pd(1)-I(1)
90.71(14)
88.91(5)
176.55(11)
87.93(11)
177.04(12)
92.39(11)
P(1)-Pd-P(2)
Cl(1)-Pd-Cl(2)
P(1)-Pd-Cl(2)
P(1)-Pd-Cl(1)
P(2)-Pd-Cl(1)
P(2)-Pd-Cl(2)
90.19(3)
92.49(3)
87.48(3)
173.20(3)
90.17(3)
176.28(3)
Ta ble 3. P r op en e/Ca r bon Mon oxid e
of these terpolymer products rises to values up to
Cop olym er iza tion Exp er im en ts w ith Ca ta lysts
4a -g a n d Eth en e/P r op en e/CO Ter p olym er iza tion
(P F P ) Usin g 4b
Mh w ≈ 8 × 105 g mol-1 (activity: 14 kg [mol(Pd) × h]-1
,
Table 3, entry 8), which belong to the highest ever
reported values for this versatile class of materials.
To optimize the effect of a nonsymmetric catalyst
architecture, the four m-CF3 groups in 4b were ex-
changed by sterically less demanding m-CH3 and m-F
substituents, affording the nonsymmetric complex spe-
cies 4c and 4d , respectively. This, however, did not lead
to substantial improvements relative to 4g, with respect
to both catalyst activity and product molecular weight.
Introduction of CF3 groups in 2- (4e) or fluorine sub-
stituents in the 2,4,6-position (4f) on two of the four
aromatic units resulted in a significant reduction of
catalyst performance, so that in the case of 4e only low
molecular weight propene/CO copolymers in low yield
could be obtained.
e
entry catalyst yieldc activityd Mh w Mh w/Mh n regioreg.f flexible
1a
2a
3a
4a
5a
6a
7a
8b
4a
4b
4c
4d
4e
4f
1.3
10.7
3.4
4.0
0.4
1.9
2.9
4.4
1.5
12.7
4.1
4.8
0.5
2.3
3.5
13.7
1.0
4.7
1.7
2.0
0.3
1.1
1.6
7.7
1.8
1.7
1.5
1.5
1.4
1.4
1.5
1.6
80
71
64
58
68
66
56
g
no
yes
yes
yes
yes
yes
yes
yes
4g
4b
a
P/CO copolymerization: 250 mL steel autoclave, catalyst (40
µmol), CH2Cl2 (150 mL), MeOH (0.25 mL), propene (60 g), con-
b
stant pressure CO (60 bar), 25 °C, 21 h. E/P/CO terpolym-
erization: 250 mL steel autoclave, catalyst (15 µmol), CH2Cl2 (150
mL), MeOH (0.25 mL), propene (60 g), ethene (6 s pulse, 2 h
interval), constant pressure CO (60 bar), 25 °C, 21 h. c [g].
[kg(mol(Pd) h)-1]. e [× 105 g mol-1], determined by GPC in THF.
d
The present study used six symmetric and nonsym-
metric CH3-, CF3-, and F-substituted complexes for the
copolymerization of propene and CO. Only the nonsym-
metric catalyst 4b, bearing four m-CF3 groups, shows
properties (activity, product molecular weight) that are
f [%], ratio of head-tail units (H-T), determined by 13C NMR.g Not
determined.
superior to our reference 4g. We have right now no
genuine and consistent explanation for the outstanding

3910 Organometallics, Vol. 22, No. 19, 2003
Meier et al.
56%). This indicates that the 1,2-insertion of propene
is controlled by the size of the phenyl groups. However,
these arguments cannot be used to understand the high
activity of 4b relative to 4c,d .23 All three nonsymmetric
catalysts contain four substituents in m-position. If the
size of these groups controls the rates, 4d would be
expected to be the fastest catalyst. However, 4c and 4d
show activities and molecular weights that are very
similar to the dppp catalyst 4g, and only 4b has optimal
properties. One contribution to this effect could be found
in the slightly raised regioregularity of 4b products,
because the reduced rate for 2,1-insertions should
decrease the concentration of species with a secondary
carbon atom attached to the Pd(II) center and should
therefore add to the overall chain growth rate. However,
we do not think that this is a major contribution.
F igu r e 5. Comparison of catalyst activities and molecular
weights.
Con clu sion
In our search for propene/CO copolymerization cata-
lysts with improved performance, the present investiga-
tions lead to nonsymmetric Pd(II)-phosphine complexes
as a new and successful structural motif. In particular,
the substitution pattern of the nonsymmetric catalyst
4b, bearing 3,5-bis(trifluoromethyl)phenyl substituents
on one phosphorus moiety, proved to be surprisingly
efficient, leading to high activities (13-14 kg [mol(Pd)
× h]-1) and enabled us to produce flexible propene/CO
copolymers with high (Mh w ) 4.7 × 105 g mol-1) and
C2/C3/CO terpolymer of ultrahigh molecular weight (Mh w
) 8 × 105 g mol-1). The solid state structures of all
applied catalyst precursors were determined in order
to find a structural explanation of this effect. The
results, however, give right now no genuine explanation
for the outstanding performance of only 4b. Further
investigations will be directed to gain a deeper insight
into the basic mechanisms to understand this effect and
to apply it to the production of new materials, using
different monomer combinations.
Ta ble 4. 31P NMR Sh ifts of th e P (Ar )2 P a r t of
Liga n d s 1a -f a n d Com p lexes 4a -f
a
b
c
d
e
f
ligand 1a
-14.9 -13.8 -17.0 -12.4 -26.7 -53.1
21.1 14.3 12.0 14.4 31.4 -19.6
complex 4b
[ppm], measured in CDCl3, 31P NMR shifts of P(Ph)2 parts
a
b
ranging between -16.5 and -17.3 ppm. [ppm], measured in
CD3CN, 31P NMR shifts of P(Ph)2 parts ranging between 14.4 and
12.0 ppm.
performance of 4b. A comparison of the 31P NMR spectra
of the ligands 1a -f and of the corresponding dicationic
palladium complexes 4a -f (Table 4) does not point
toward electron-donating or -withdrawing ligand effects
as a satisfying reason for the observed catalytic poten-
tials. The chemical shifts of the P atoms bearing
substituted phenyl groups (1a -d ) are nearly identical;
only 1f shows a significant chemical shift deviation.
However, catalyst 4f gives polymerization properties
that are mediocre, with values for activity and molecular
weight similar to 4a ,g.20 Coordination of the ortho CF3-
substituted ligand on palladium in complex 4e leads to
Exp er im en ta l Section
a
31P NMR shift of the aryl-substituted phosphorus,
Gen er a l P r oced u r es. All reactions were performed under
argon atmosphere using standard Schlenk techniques. Sol-
vents were dried by distillation from drying agents (CaH2 for
dichloromethane, P2O5 for CCl4, LiAlH4 for diethyl ether, THF,
and n-pentane) and deoxygenated. Dry acetonitrile was re-
ceived from Roth, deoxygenated in vacuo, and stored over 3 Å
molecular sieves. DMSO and H2O were deoxygenated in vacuo.
Chemicals were used as received from Merck (Br2), Aldrich
(1,3-dibromopropane, AgBF4), Lancester (5-bromo-m-xylene),
and ABCR (1-bromo-3,5-bis(trifluoromethyl)benzene, 1-bromo-
3,5-difluorobenzene, 1-bromo-2,4,6-trifluorobenzene, 1-bromo-
2-(trifluoromethyl)benzene). Bis[3,5-bis(trifluoromethyl)phenyl]-
phosphine,24 3-chloropropyldiphenylphosphine,25 diisopropyl-
3-(diphenylphosphino)propylphosphonate,26 (COD)PdCl2,27 and
4g28 were prepared according to literature procedures. 1H, 13C,
situated downfield of the PPh2 signal, quite in contrast
to the 31P spectrum of ligand 1e.21 From steric consid-
erations (see structure discussion) it is obvious that 4a
is sterically overcrowded, so that activity and molecular
weight are low, due to hindrance of monomer coordina-
tion and orientation. The same effect can be used to
explain the high regioregularity (H-T: 80%, Table 3)
of products resulting from 4a , leading to a preference
of 1,2- over 2,1-propene insertions.22 It is also conceiv-
able that catalysts bearing CF3 or F substituents in
ortho-position (4e,f) show reduced activities and product
molecular weights, due to steric hindrance again or to
metal-F interactions, which compete with olefin coor-
dination. The regioregularity of propene ketones result-
ing from 4b-d ,g seems also to follow the steric demand
of the substituents decreasing in the order CF3 (4b;
H-T: 71%) > CH3 (4c; 64%) > F (4d ; 58%) > H (4g;
(23) In the present study the increase of activity is always connected
with higher product molecular weights. This indicates that the
enhanced activity results from a faster olefin insertion rate, which was
shown to be the rate-limiting step in this polymerization reaction.
(24) Casey, P. C.; Paulsen, E. L.; Beuttenmueller, E. W.; Proft, B.
R.; Petrovich, L. M.; Matter, B. A.; Powell, D. R. J . Am. Chem. Soc.
1997, 119, 11817.
(20) This is in slight contrast to previous work of Consiglio et al.
(cf. ref 6a). These authors found a relation between an activity increase
and electron-withdrawing effects of CF3-substituted, chiral bisphos-
phine Pd(II) catalysts.
(25) Uriarte, R.; Mazanec, T. J .; Tau, K. D.; Meek, D. W. Inorg.
Chem. 1980, 19, 79.
(21) For similar shift behavior see ref 7a.
(22) This gives in the case of catalyst 4a a regioregular and thus
brittle material.
(26) Weight, A.; Bischoff, S. Phosphorus, Sulfur Silicon 1995, 102,
91.
(27) Drew, D.; Doyle, J . R. Inorg. Synth. 1972, 13, 52.

Nonsymmetric Palladium Complexes
Organometallics, Vol. 22, No. 19, 2003 3911
19F, and 31P NMR spectra were recorded on a Bruker DRX 400.
In 1H and 13C spectra TMS was used as internal standard.
31P shifts have been referenced to the external standard
H3PO4 (85%). 19F NMR spectra are calibrated to CCl3F as
internal standard. IR spectra were measured on a Bruker IFS
113v spectrometer. Mass spectra were acquired with Finnigan
SSQ 7000 and TSQ 7000 instruments. X-ray structure analy-
ses were performed as described. In the polymerization experi-
ments propene (2.6), ethene (2.7), and carbon monoxide (2.0)
were used without further purification as received from BASF.
Ca u tion . Grignard reagents of fluorinated aromatics can
be explosive in the solid state and therefore should be handled
carefully in diluted solution.
1,3-Bis{bis[3,5-bis(tr iflu or om eth yl)ph en yl]ph osph in o}-
p r op a n e (1a ). Bis(3,5-bis(trifluoromethyl)phenyl)phosphine
(5) (7.06 g, 15.41 mmol) was suspended in DMSO (60 mL).
Addition of an aqueous solution of KOH (1.12 g, 20.03 mmol,
1.5 mL of H2O) gave a dark red solution. After stirring for 30
min 1,3-dibromopropane (1.55 g, 7.71 mmol) was added and
stirred for a further 48 h at room temperature. The reac-
tion mixture was poured into H2O. The precipitate was
separated, dissolved in ether, washed three times with water,
dried (Na2SO4), and evaporated. The residue was washed with
n-pentane and evaporated in vacuo.
Yield: 5 g (68%). 1H NMR (CDCl3): δ 7.88 (s, 4H, para Ar),
7.77 (d, 8H, ortho Ar), 2.35 (t, 4H, -CH2P), 1.61 (m, 2H,
-CH2-). 13C NMR (CDCl3): δ 139.93 (d, ipso Ar), 132.7-132.1
(m, ortho Ar, meta Ar), 123.65 (sept, para Ar), 122.89 (q, CF3),
28.86 (vt, -CH2P), 21.92 (t, -CH2-). 31P{1H} NMR (CDCl3):
δ -14.88 (s). 19F{1H} NMR (CDCl3): δ -63.62 (s). MS (EI, m/z
(%)): 743 (100) [M - Ar]+, 956 (15) [M]+, 937 (8) [M - F]+.29
1-Dip h en ylp h osp h in o-3-{bis[3,5-bis(tr iflu or om eth yl)-
p h en yl]p h osp h in o}p r op a n e (1b ). Bis(3,5-bis(trifluoro-
methyl)phenyl)phosphine (5) (6.34 g, 13.84 mmol) was sus-
pended in DMSO (50 mL) and deprotonated by addition of
aqueous KOH solution (1.01 g, 17.99 mmol, 2 mL of H2O). The
dark red solution was stirred for 30 min. A solution of
3-chloropropyldiphenylphosphine (6) (3.40 g, 12.94 mmol) in
DMSO (15 mL) was added, and the mixture was stirred for
24 h at room temperature and an additional 2 h at 50 °C. The
reaction mixture was poured into water (300 mL) after cooling
to ambient temperature. NaCl was added to the resulting
emulsion. The separated oily phase was dissolved in ether,
washed three times with water, dried over Na2SO4, and
evaporated. Excess bis(3,5-bis(trifluoromethyl)phenyl)phos-
phine was removed by distillation at 130 °C in vacuo.
Yield: 6.6 g (70%). 1H NMR (CDCl3): δ 7.86 (s, 2H, para
Ar), 7.75 (d, 4H, ortho Ar), 7.39-7.32 (m, 4H, Ph), 7.31-7.27
(m, 6H, Ph), 2.27 (t, 2H, -CH2PAr2), 2.22 (t, 2H, -CH2PPh2),
1.59 (m, 2H, CH2). 13C NMR (CDCl3): δ 140.65 (d, ipso Ar),
138.00 (d, ipso Ph), 132.8-132.3 (m, ortho Ph, meta Ar, ortho
Ar), 123.34 (sept, para Ar), 122.99 (q, CF3), 29.37 (vt, -CH2P),
28.97 (vt, -CH2P′), 22.15 (vt, -CH2-). 31P{1H} NMR (CDCl3):
δ -13.84 (s, PAr2), -17.16 (s, PPh2). 19F{1H} NMR (CDCl3): δ
-63.45 (s). MS (CI, m/z (%)): 665 (100) [M - F]+, 685 (89)
[MH]+, 607 (6) [M - Ph]+, 471 (5) [M - Ar]+.
addition of the corresponding aryl bromide in THF to an excess
of magnesium turnings in THF and heating to slight reflux
for 30 min. The filtered Grignard solution was added slowly
to the suspension of 9 at -78 °C. After 15 min the reaction
mixture was allowed to warm to room temperature and stirred
overnight. It was hydrolyzed with water and adjusted to pH
7.
After special workup, described in detail for each of the
ligands, the bisphosphines 1c-f are yielded in a purity of 100%
in 31P NMR but containing some impurities in 1H NMR. By
conversion to the corresponding dichloro palladium(II) deriva-
tives a complete purification is easily possible. The pure
uncoordinated ligands are accessible by treating the complexes
with aqueous sodium cyanide solution in CH2Cl2 overnight and
subsequent workup.
1-Dip h en ylp h osp h in o-3-[bis(3,5-d im eth ylp h en yl)p h os-
p h in o]p r op a n e (1c). Following the general procedure, 8 (2.19
g, 8.41 mmol, 80 mL of CCl4) was bromated with Br2 (2.69 g,
16.83 mmol, 10 mL of CCl4) and suspended in ether (100 mL).
3,5-Dimethylphenylmagnesium bromide was prepared from
5-bromo-m-xylene (4.68 g, 25.24 mmol, 20 mL of THF) and
Mg (0.77 g, 31.56 mmol, 20 mL of THF). After hydrolyses some
CH2Cl2 was added and the organic layer was separated. The
aqueous phase was extracted twice with CH2Cl2. The combined
organic extracts were washed with water, dried (Na2SO4), and
evaporated. Purification of the crude product by chromatog-
raphy over silica with CH2Cl2 gave 1c as an oily product.
1
Yield: 1.5 g (38%). H NMR (CDCl3): δ 7.38-7.33 (m, 4H,
Ph), 7.30-7.26 (m, 6H, Ph), 6.98 (br d, 4H, ortho Ar), 6.91 (br
s, 2H, para Ar), 2.25 (s, 12H, CH3), 2.21-2.12 (m, 4H, -CH2P),
1.60 (m, 2H, -CH2-). 13C NMR (CDCl3): δ 138.69 (d, ipso),
138.31 (d, ipso′), 137.66 (d, meta Ar), 132.65 (d, ortho Ph),
130.35 (d, ortho Ar), 129.04 (s, para Ar), 128.42 (s, para Ph),
128.32 (d, meta Ph), 29.87-29.40 (m, -CH2P, -CH2P′), 22.55
(vt, -CH2-), 21.27 (s -CH3). 31P{1H} NMR (CDCl3): δ -16.74
(s), -16.96 (s). MS (CI, m/z (%)): 469 (100) [MH]+, 391 (15)
[M - Ph]+, 363 (8) [M - Ar]+. Anal. Calcd for C31H34P2: C,
79.46; H, 7.31. Found: C, 79.21; H, 7.17.
1-Dip h en ylp h osp h in o-3-[bis(3,5-d iflu or op h en yl)p h os-
p h in o]p r op a n e (1d ). Following the general procedure de-
scribed above, 9 was prepared from 8 (4.40 g, 16.91 mmol, 180
mL of CCl4) and Br2 (5.40 g, 33.81 mmol, 20 mL of CCl4) and
suspended in ether (200 mL). The required 3,5-difluorophen-
ylmagnesium bromide was obtained from 1-bromo-3,5-difluo-
robenzene (9.80 g, 50.72 mmol, 20 mL of THF) and Mg (1.55
g, 63.39 mmol, 20 mL of THF). For further workup the organic
layer was separated, and the aqueous phase was extracted
three times with ether. The combined organic phases were
dried (Na2SO4), and the solvent was removed in vacuo. The
residue was extracted several times with n-pentane. Evapora-
tion of the combined organic solutions gave an oily product,
which was purified by chromatography over silica with
CH2Cl2.
1
Yield: 3.4 g (42%). H NMR (CDCl3): δ 7.40-7.34 (m, 4H,
Ph), 7.32-7.28 (m, 6H, Ph), 6.83 (m, 4H, ortho Ar), 6.75 (tt,
2H, para Ar), 2.19 (t, 2H, -CH2P), 2.13 (t, 2H, -CH2P′), 1.56
(m, 2H, -CH2-). 13C NMR (CDCl3): δ 162.89 (ddd, meta Ar),
142.05 (dt, ipso Ar), 138.21 (d, ipso Ph), 132.63 (d, ortho Ph),
128.67 (s, para Ph), 128.44 (d, meta Ph), 115.03 (vsex, ortho
Ar), 104.63 (t, para Ar), 29.44 (vt, -CH2P), 29.07 (vt, -CH2P′),
22.01 (vt, -CH2-). 31P{1H} NMR (CDCl3): δ -12.42 (s, PAr2),
-17.17 (s, PPh2). 19F{1H} NMR (CDCl3): δ -109.01 (s). MS
(CI, m/z (%)): 485(100) [MH]+, 371(49) [M - Ar]+, 407 (9) [M
- Ph]+.
Gen er a l P r oced u r e for t h e P r ep a r a t ion of Liga n d s
1c-f. [3-(Dibromo)phosphino)propyl](diphenyl)phosphonium
bromide (9) was prepared in CCl4 from 1 equiv of 8 and 2 equiv
of Br2 according to the procedure described below. The obtained
product was cooled to -78 °C after complete evaporation of
CCl4. Precooled solvent (THF in the case of 1e and ether in
the case of 1c,d ,f) was added to suspend the solid foam. A
solution of arylmagnesium bromide was prepared by slow
1-Diph en ylph osph in o-3-{bis[(2-(tr iflu or om eth yl)ph en yl]-
p h osp h in o}p r op a n e (1e). As described in the general pro-
cedure, Br2 (3.47 g, 21.75 mmol, 15 mL of CCl4) was added to
8 (2.83 g, 18.87 mmol, 140 mL of CCl4), and the resulting
product was suspended in THF (120 mL). In this synthesis 1
equiv 9 was treated with 5 equiv of the 2-(trifluoromethyl)-
phenylmagnesium bromide, which was obtained from 1-bromo-
(28) Xu, F. Y.; Zhao, A. X.; Chien, J . C. W. Macromol. Chem. 1993,
194, 2579.
(29) Due to technical problems in elemental analysis of fluorinated
compounds only selected complexes of fluorinated ligands were char-
acterized by elemental analysis. However, NMR, MS, IR, and X-ray
structure analysis were applied to confirm composition of all reported
compounds.

3912 Organometallics, Vol. 22, No. 19, 2003
Meier et al.
2-(trifluoromethyl)benzene (12.23 g, 54.35 mmol, 40 mL of
THF) and Mg (1.65 g, 67.94 mmol, 30 mL of THF). After the
reaction was hydrolyzed, the THF was evaporated in vacuo.
The precipitated solid was separated and washed two times
with water. The residue was extracted three times with
degassed acetone, and the combined extracts were evaporated.
The remaining solid was dissolved in CH2Cl2, washed twice
with water, and dried (Na2SO4). After removing the solvent
in vacuo, the residue was washed once with a small amount
of n-pentane. The remaining residue was extracted twice with
ether. The filtered extracts were combined and evaporated.
Further purification of the crude product, performed by
chromatography over silica with CH2Cl2, gave the bisphos-
phine as an oily compound.
different orientation of the aromatic rings. Some of the CF3
groups show disordering. An additional 1.5 disordered THF
molecules per complex molecule (side occupation factor 0.75)
are incorporated in the crystal, which results in a relatively
high final R-value.
Dich lor o{1-d ip h en ylp h osp h in o-3-[b is[3,5-b is(t r iflu o-
r om eth yl)ph en yl]ph osph in o]pr opan e}palladiu m (II) (2b).
A solution of ligand 1b (2.16 g, 3.16 mmol) in CH2Cl2 (20 mL)
was added to a solution of (COD)PdCl2 (0.9 g, 3.16 mmol) in
CH2Cl2 (60 mL). After stirring the mixture for 1 h, it was
concentrated and the complex was precipitated with n-pen-
tane. Washing with ether and n-pentane and drying in vacuo
gave the complex 2b as a yellow solid.
Yield: 2.6 g (96%). 1H NMR (CDCl3): δ 8.13 (br d, 4H, ortho
Ar), 7.96 (br s, 2H, para Ar), 7.71 (m, 4H, Ph), 7.47 (m, 2H,
Ph), 7.37 (m, 4H, Ph), 2.64-2.48 (m, 4H, -CH2P), 2.09 (m,
2H, -CH2-). 31P{1H} NMR (CDCl3): δ 13.33 (d), 13.02 (d).
19F{1H} NMR (CDCl3): δ -63.38 (s). MS (FAB, m/z (%)): 827
(100) [M - Cl]+, 790 (18) [M - 2Cl]+, 749 (12) [M - Cl,Ph]+,
577 (9) [M - 2Cl,Ar]+. Anal. Calcd for C31H22Cl2F12P2Pd: C,
43.21; H, 2.57. Found: C, 43.01; H, 2.57.
1
Yield: 2.2 g (38%). H NMR (CDCl3): δ 7.71-7.65 (m, 2H,
arom.), 7.45-7.32 (m, 10H, arom.), 7.30-7.25 (m, 6H, arom.),
2.24-2.12 (m, 4H, -CH2P), 1.62 (m, 2H, -CH2-). 13C NMR
(CDCl3): δ 138.26 (d, ipso Ph), 136.84 (d, ipso Ar), 134.12 (qd,
CCF3), 133.19 (s, Ar), 132.64 (d, ortho Ph), 131.46 (s, Ar),
128.74 (s, Ar), 128.57 (s, para Ph), 128.40 (d, meta Ph), 126.67
(br, m, Ar), 124.15 (q, CF3), 30.19 (vt, -CH2P), 29.57 (vt,
-CH2P′), 22.40 (dd, -CH2-). 31P{1H} NMR (CDCl3): δ -17.28
(s, PPh2), -26.70 (sept, PAr2). 19F{1H} NMR (CDCl3): δ -57.66
(d). MS (CI, m/z (%)): 594 (100) [MH]+, 529 (57) [M - F]+,
403 (37) [M - Ar]+.
Single-crystals of 2b suitable for X-ray analysis were
obtained by crystallization from acetonitrile solution layered
with ether.
Dic h lor o{1-d ip h e n y lp h osp h in o-3-[b is(3,5-d im e t h -
ylp h en yl)p h osp h in o]p r op a n e}p a lla d iu m (II) (2c). A solu-
tion of (COD)PdCl2 (0.46 g, 1.60 mmol) in CH2Cl2 (40 mL) was
treated with a solution of 1c (0.75 g, 1.60 mmol) in CH2Cl2
(20 mL) and stirred for 1 h. The mixture was concentrated in
vacuo, and the complex was precipitated by adding n-pentane.
Washing with ether and n-pentane and drying in vacuo gave
complex 2c as a yellow-orange solid.
1-Diph en ylph osph in o-3-[bis(2,4,6-tr iflu or oph en yl)ph os-
p h in o]p r op a n e (1f). According to the general procedure, 9
was prepared from 8 (4.18 g, 16.05 mmol, 180 mL of CCl4)
and Br2 (5.13 g, 32.1 mmol, 20 mL of CCl4) and suspended in
ether (200 mL). A solution of 2,4,6-trifluorophenylmagnesium
bromide was obtained from 1-bromo-2,4,6-trifluorobenzene
(10.16 g, 48.15 mmol, 30 mL of THF) and Mg (1.47 g,
60.18 mmol, 20 mL of THF). After adjusting to pH 7 the
organic layer was separated and the aqueous phase was
extracted three times with ether. The combined organic layers
were dried (Na2SO4), and the solvent was removed in vacuo.
The yielded brownish oil was purified by chromatography over
silica with CH2Cl2. The oily product was extracted several
times with n-pentane. The extracts were combined and
evaporated to give 1f as an oil.
1
Yield: 1.0 g (94%). H NMR (CDCl3): δ 7.81-7.74 (m, 4H,
Ph), 7.47-7.33 (m, 10H, arom), 7.04 (br s, 2H, para Ar),
2.39-2.28 (m, 4H, -CH2P), 2.26 (s, 12H, -CH3), 1.99 (m, 2H,
-CH2-). 31P{1H} NMR (CDCl3): δ 12.7 (d), 11.4 (d). MS (FAB,
m/z (%)): 609 (100) [M - Cl]+, 574 (20) [M - 2Cl]+, 533 (6) [M
- Cl,Ph]+. Anal. Calcd for C31H34Cl2P2Pd: C, 57.65; H, 5.31.
Found: C, 57.48; H, 5.24.
Single-crystals of 2c suitable for X-ray analysis were
obtained by crystallization from CH2Cl2 solution layered with
n-pentane. The crystals include two independent complex
molecules and four CH2Cl2 molecules per unit cell.
D ic h lo r o {1-d ip h e n y lp h o s p h in o -3-[b is (3,5-d iflu o -
r op h en yl)p h osp h in o]p r op a n e}p a lla d iu m (II) (2d ). A solu-
tion of 1d (1.96 g, 4.06 mmol) in CH2Cl2 (20 mL) was added to
(COD)PdCl2 (1.16 g, 4.06 mmol) in CH2Cl2 (80 mL). After
stirring at room temperature for 1 h the solution was concen-
trated in vacuo. The complex was precipitated by addition of
n-pentane and washed with ether and n-pentane. Drying in
vacuo gave 2d as a microcrystalline solid.
Yield: 2.6 g (95%). 1H NMR (DMSO-d6): δ 7.76 (m, 4H,
arom), 7.57-7.44 (m, 12H, arom), 2.83 (m, 2H, -CH2P), 2.72
(m, 2H, -CH2P′), 1.78 (m, 2H, -CH2-). 31P{1H} NMR (DMSO-
d6): δ 16.5 (br), 13.3 (br). 19F{1H} NMR (DMSO-d6): δ -107.50
(s). MS (FAB, m/z (%)): 625 (100) [M - Cl]+, 589 (37) [M -
2Cl]+, 547 (26) [M - Cl,Ph]+. Anal. Calcd for C27H22Cl2F4P2-
Pd: C, 49.01; H, 3.35. Found: C, 48.79; H, 3.48.
1
Yield: 4.2 g (51%). H NMR (CDCl3): δ 7.39-7.33 (m, 4H,
Ph), 7.31-7.27 (m, 6H, Ph), 6.58 (m, 4H, meta Ar), 2.57 (m,
2H, -CH2PAr2), 2.19 (t, 2H, -CH2PPh2), 1.54 (m, 2H, -CH2-
). 13C NMR (CDCl3): δ 164.73 (dm, ortho Ar), 163.91 (dm, para
Ar), 138.30 (d, ipso Ar), 132.62 (d, ortho Ph), 128.53 (s,
para Ph), 128.36 (d, meta Ph), 108.7-107.3 (m, ipso Ar),
101.0-100.2 (m, meta Ar), 29.26 (dd, -CH2PPh2), 25.31 (m,
-CH2PAr2), 22.82 (dd, -CH2-). 31P{1H} NMR (CDCl3):
δ
-16.54 (s, PPh2), -53.12 (quint, PAr2). 19F{1H} NMR
(CDCl3): δ -98.39 (dd, ortho F), -106.30 (t, para F). MS (CI,
m/z (%)): 521 (100) [MH]+, 389 (26) [M - Ar]+, 501 (14)
[M - F]+, 443 (8) [M - Ph]+.
Dich lor o{1,3-bis[b is[3,5-b is(t r iflu or om et h yl)p h en yl]-
ph osph in o]pr opan e}palladiu m (II) (2a). A solution of (COD)-
PdCl2 (0.76 g, 2.65 mmol) in CH2Cl2 (40 mL) was treated with
a solution of 1a (2.53 g, 2.65 mmol) in CH2Cl2 (25 mL). After
stirring for 1 h, the main CH2Cl2 amount was removed by an
argon stream due to foaming in vacuo. For precipitation
n-pentane was added, and the product was washed with ether
and n-pentane. Drying in vacuo gave product 2a as a pale
yellow solid.
D ic h lo r o {1-d ip h e n y lp h o s p h in o -3-[b is [2-(t r iflu o -
r om eth yl)ph en yl]ph osph in o]pr opan e}palladiu m (II) (2e).
A solution of (COD)PdCl2 (1.96 g, 6.87 mmol) in CH2Cl2 (120
mL) was treated with a solution of bisphosphine 1e (3.77 g,
6.87 mmol) in CH2Cl2 (40 mL) and stirred for 1 h. After
concentrating the solution n-pentane was added for precipita-
tion. The solid was washed with ether and n-pentane and dried
in vacuo.
1
Yield: 2.9 g (95%). H NMR (acetone-d6): δ 8.53 (br d, 8H,
ortho Ar), 8.28 (br s, 4H, para Ar), 3.29 (m, 4H, -CH2P), 2.38
(m, 2H, -CH2-). 31P{1H} NMR (acetone-d6): δ 16.11 (s).
19F{1H} NMR (acetone-d6): δ -62.45 (s). MS (FAB, m/z (%)):
1097 (100) [M - Cl]+, 1062 (23) [M - 2Cl]+, 849 (23) [M -
2Cl,Ar]+. Anal. Calcd for C35H18Cl2F24P2Pd: C, 37.08; H, 1.60.
Found: C, 36.89; H, 1.66.
1
Yield: 4.8 g (96%). H NMR (C2D2Cl4): δ 9.41 (m, 1H, Ar)
Single crystals of 2a suitable for X-ray analysis were grown
from THF solution layered with cyclohexane. The unit cell
contains two independent complex molecules with a slightly
7.82-7.32 (m, 16H, arom), 7.02 (m, 1H, Ar), 2.80-2.62 (m,
2H), 2.30-2.04 (m, 3H), 1.71-1.50 (m, 1H). 31P{1H} NMR
(C2D2Cl4): δ 37.14 (m, PAr2), 12.47 (d, PPh2). 19F{1H} NMR

Nonsymmetric Palladium Complexes
Organometallics, Vol. 22, No. 19, 2003 3913
(C2D2Cl4): δ -54,27 (s), -54.37 (d). MS (FAB, m/z (%)): 689
(100) [M - Cl]+, 653 (48) [M - 2Cl]+, 611 (7) [M - Cl,Ph]+.
D i c h lo r o {1-d i p h e n y lp h o s p h i n o -3-[b i s (2,4,6-t r i -
flu or op h en yl)p h osp h in o]p r op a n e}p a lla d iu m (II) (2f).
Ligand 1f (3.58 g, 6.88 mmol) was dissolved in CH2Cl2 (30 mL)
and added to a solution of (COD)PdCl2 (1.96 g, 6.88 mmol) in
CH2Cl2 (120 mL). After 1 h the product was precipitated by
concentrating the solution in vacuo. The precipitation was
completed by adding n-pentane. The complex was washed with
ether and n-pentane and dried in vacuo.
Yield: 4.6 g (97%). 1H NMR (DMSO-d6): δ 7.84 (m, 4H,
Ph), 7.63-7.51 (m, 6H, Ph), 7.40 (m, 4H, Ar), 2.62 (m, 2H,
-CH2P), 2.54 (m, 2H, -CH2P′), 1.88 (m, 2H, -CH2-). 31P{1H}
NMR (DMSO-d6): δ 16.37 (d), -16.23 (m). 19F{1H} NMR
(DMSO-d6): δ -93.18 (vt, ortho F), -100.99 (t, para F). MS
(FAB, m/z (%)): 661 (100) [M - Cl]+, 625 (37) [M - 2Cl]+. Anal.
Calcd for C27H20Cl2F6P2Pd: C, 46.48; H, 2.89. Found: C, 46.17;
H, 2.99.
Single crystals of 2f suitable for X-ray analysis were grown
from DMSO solution layered with ether. Four molecules of
DMSO were found to be included within the unit cell.
Diiodo{1-diph en ylph osph in o-3-[bis(3,5-diflu or oph en yl)-
p h osp h in o]p r op a n e}p a lla d iu m (II) (3d ). Compound 3d was
prepared according to the procedure described for 3e from the
dichloro complex 2d (0.45 g, 0.68 mmol), DMSO (10 mL), and
NaI (0.41 g, 2.72 mmol) and isolated as a red-orange solid.
Yield: 0.31 g (54%). 1H NMR (acetone-d6): δ 7.83-7.76 (m,
4H, arom), 7.54-7.43 (m, 10H, arom), 7.20 (tt, 2H, para Ar),
2.92 (m, 2H, -CH2P), 2.82 (m, 2H, -CH2P′), 2.12 (m, 2H,
-CH2-). 31P{1H} NMR (acetone-d6): δ 3.37 (dquint, PAr2),
1.42 (d, PPh2). 19F{1H} NMR (acetone-d6): δ -108.12 (d). MS
(FAB, m/z (%)): 844 (6) [M]+, 717 (100) [M - I]+, 589 (29)
[M - I,HI]+.
(m, 2H, -CH2-), 2.09 (s, 6H, CH3CN). 31P{1H} NMR (acetone-
d6): δ 18.57 (s). 19F{1H} NMR (acetone-d6): δ -62.32 (s, CF3),
-148.16 (s, BF4). IR (KI, ν (cm-1)): 2329, 2300 (w, CtN); 1130
(sbr, BF4). MS (FAB, m/z (%)): 1061 (25) [M - 2CH3CN,2BF4]+,
605 (100) [M - 2CH3CN,2BF4,PAr2]+.
Dia ce t on it r ile {1-d ip h e n ylp h osp h in o-3-[b is[3,5-b is-
(tr iflu or om eth yl)p h en yl]ph osph in o]pr op a n e}p a lla d iu m -
(II) Ditetr a flu or obor a te (4b). Complex 2b (1.12 g, 1.30
mmol) was dissolved in acetonitrile (70 mL), and AgBF4 (0.51
g, 2.60 mmol) was added. After stirring for 2 h the solution
was separated from the precipitated silver salt and evaporated
in vacuo. The residue was extracted with CH2Cl2. After the
extract was concentrated in vacuo and filtered, the complex
was precipitated by adding n-pentane. Washing the product
with n-pentane and drying in vacuo gave complex 4b.
1
Yield: 1.1 g (81%). H NMR (CD3CN): δ 8.28 (s, 2H, para
Ar), 8.11 (d, 4H, ortho Ar), 7.68-7.59 (m, 6H, Ph), 7.56-7.49
(m, 4H, Ph), 2.98-2.85 (m, 4H, -CH2P), 2.30 (m, 2H, -CH2-
), 1.95 (s, CH3CN). 31P{1H} NMR (CD3CN): δ 14.3 (d), 14.1
(d). 19F{1H} NMR (CD3CN): δ -62.1 (s, CF3), -150.1 (s, BF4).
IR (KI, ν (cm-1)): 2328, 2300 (w, CtN); 1130 (sbr, BF4). MS
(FAB, m/z (%)): 790 (100) [M - 2CH3CN,2BF4]+.
Dia ce t on it r ile {1-d ip h e n ylp h osp h in o-3-[b is(3,5-d i-
m eth ylp h en yl)p h osp h in o]p r op a n e}p a lla d iu m (II) d itet-
r a flu or obor a te (4c). AgBF4 (0.24 g, 1.26 mmol) was added
to a solution of 2c (0.41 g, 0.63 mmol) in acetonitrile (80 mL).
Stirring for 2 h was followed by workup described in the
procedure of compound 4b to give 4c.
Yield: 0.4 g (78%). 1H NMR (CD3CN): δ 7.66-7.58 (m, 6H,
Ph), 7.55-7.49 (m, 4H, Ph), 7.23 (br s, 4H, ortho Ar), 7.20 (br
s, 2H, para Ar), 2.77 (m, 4H, -CH2P), 2.29 (s, 12H, -CH3),
2.22 (m, 2H, -CH2-), 1.95 (s, CH3CN). 31P{1H} NMR
(CD3CN): δ 13.0 (br), 12.0 (br). 19F{1H} NMR (CD3CN): δ
-150.2 (s, BF4). IR (KI, ν (cm-1)): 2325, 2297 (w, CtN); 1061
(sbr, BF4). MS (FAB, m/z (%)): 593 (56) [M - 2CH3CN,
BF4,BF3]+, 574 (100) [M - 2CH3CN,2BF4]+.
Single crystals of 3d suitable for X-ray analysis were grown
from a chloroform solution layered with n-hexane. The crystals
enclose strongly disordered solvent molecules, which could not
be identified and located, even though satisfying final R-indices
have been achieved in structure refinement.
Dia ce t on it r ile {1-d ip h e n ylp h osp h in o-3-[b is(3,5-d i-
flu or op h en yl)p h osp h in o]p r op a n e}p a lla d iu m (II) Ditet-
r a flu or obor a te (4d ). A solution of 2d (1.56 g, 2.36 mmol) in
acetonitrile (50 mL) was treated with AgBF4 (0.92 g, 4.72
mmol) and stirred for 12 h. After workup according to the
procedure of 4b, complex 4d was isolated as a pale yellow solid.
Diiodo{1-diph en ylph osph in o-3-[bis[2-(tr iflu or om eth yl)-
p h en yl]p h osp h in o]p r op a n e}p a lla d iu m (II) (3e). A solution
of the dichloro complex 2e (3.68 g, 5.07 mmol) in DMSO (80
mL) was treated with NaI (3.04 g, 20.3 mmol) and stirred for
48 h at room temperature. After addition of water (500 mL),
the resulting mixture was extracted with CH2Cl2. The com-
bined CH2Cl2 extracts were washed three times with water,
dried (Na2SO4), and evaporated. The crude product was
purified by chromatography over silica with CH2Cl2 and
precipitated with n-pentane to give 3e as a red-orange micro-
crystalline solid.
1
Yield: 1.6 g (80%). H NMR (CD3CN, 343 K): δ 7.72-7.63
(m, 6H, Ph), 7.58-7.53 (m, 4H, Ph), 7.32-7.25 (m, 4H, ortho
Ar), 7.20 (tt, 2H, para Ar), 2.86-2.77 (m, 4H, -CH2P), 2.29
(m, 2H, -CH2-), 1.95 (s, CH3CN). 31P{1H} NMR (CD3CN): δ
14.4 (m), 12.7 (m). 19F{1H} NMR (CD3CN): δ -105.5 (s, meta
F), -150.0 (s, BF4). IR (KI, ν (cm-1)): 2326, 2299 (w, CtN);
1065 (sbr, BF4). MS (FAB, m/z (%)): 609 (39) [M - 2CH3CN,
BF4,BF3]+, 590 (100) [M - 2CH3CN,2BF4]+.
1
Yield: 3.27 g (71%). H NMR (CDCl3): δ 9.58 (m, 1H, Ar),
7.91-7.34 (m, 16H, arom), 7.09 (m, 1H, Ar), 2.90-2.71 (m, 2H),
2.34-2.17 (m, 2H), 2.17-2.04 (m, 1H), 1.91-1.70 (m, 1H).
31P{1H} NMR (CDCl3): δ 23.06 (m, PAr2), -0.40 (d, PPh2).
19F{1H} NMR (CDCl3): δ -54.70 (s), -55.55 (d). MS (FAB, m/z
(%)): 781 (100) [M - I]+, 653 (44) [M - I,HI]+. Anal. Calcd for
29H24F6I2P2Pd: C, 38.33; H, 2.66. Found: C, 38.21; H, 2.54.
Crystallization from a chloroform solution layered with
n-pentane gave single crystals of 3e, which were suitable for
X-ray analysis. The crystals contain two molecules of CHCl3
per complex molecule. The carbon atom of one CHCl3 could
not be located due to disordering.
Dia c e t o n it r ile {1-d ip h e n ylp h osp h in o -3-[b is[2-(t r i-
flu or om et h yl)p h en yl]p h osp h in o]p r op a n e }p a lla d iu m -
(II) Ditetr a flu or obor a te (4e). AgBF4 (0.43 g, 2.22 mmol) was
added to a suspension of 3e (1.01 g, 1.11 mmol) in acetonitrile
(80 mL). After stirring the reaction mixture for 2 h workup
according to procedure 4b gave 4e.
Yield: 0.9 g (89%). 1H NMR (CD3CN): δ 8.61-8.47 (br, 1H,
arom), 8.07-7.37 (m, 17H, arom), 3.12-2.94 (br, 2H), 2.71 (br,
2H), 2.53-2.29 (br, 1H), 2.10-1.96 (br, 1H), 1.95 (s, CH3CN).
31P{1H} NMR (CD3CN): δ 31.4 (m, PAr2), 13.2 (d, PPh2).
19F{1H} NMR (CD3CN): δ -54.1 (s, br, CF3), -54.4 (s, br, CF3),
-150.4 (s, BF4). IR (KI, ν (cm-1)): 2327, 2299 (w, CtN); 1074
(sbr, BF4). MS (FAB, m/z (%)): 673 (22) [M - 2CH3CN,
BF4,BF3]+, 654 (100) [M - 2CH3CN,2BF4]+.
D ia c e t o n it r ile {1-d ip h e n y lp h o s p h in o -3-[b is (2,4,6-
tr iflu or oph en yl)ph osph in o]pr opan e}palladiu m (II) Ditet-
r a flu or obor a te (4f). Complex 2f (1.93 g, 2.76 mmol) was
suspended in acetonitrile (100 mL). After AgBF4 (1.07 g, 5.52
mmol) was added, the suspension was stirred for 12 h.
Following the procedure described for 4b the suspension was
worked up to give 4f.
C
Dia ce t on it r ile {1,3-b is[b is[3,5-b is(t r iflu or om e t h yl)-
p h en yl]p h osp h in o]p r op a n e}p a lla d iu m (II) Ditetr a flu o-
r obor a te (4a ). AgBF4 (0.61 g, 3.12 mmol) was added to a
solution of 2a (1.77 g, 1.56 mmol) in acetonitrile (80 mL). After
stirring for 2 h the solution was filtered and concentrated in
vacuo. The solution was filtered again and the complex
precipitated with ether. The solid was washed with ether and
n-pentane and dried in vacuo to give 4a .
Yield: 1.4 g (68%). 1H NMR (acetone-d6): δ 8.55 (d, 8H,
ortho Ar), 8.44 (s, 4H, para Ar), 3.58 (m, 4H, -CH2P), 2.71

3914 Organometallics, Vol. 22, No. 19, 2003
Meier et al.
Yield: 1.9 g (76%). 1H NMR (CD3CN): δ 7.75-7.65 (m, 6H,
Ph), 7.64-7.54 (m, 4H, Ph), 7.03 (m, 4H, Ar), 2.99 (m, 2H,
-CH2P), 2.77 (m, 2H, -CH2P’), 2.32 (m, 2H, -CH2-), 1.95 (s,
CH3CN). 31P{1H} NMR (CD3CN): δ 14.4 (d, PPh2), -19.6 (m,
PAr2). 19F{1H} NMR (CD3CN): δ -93.4 (vt, ortho F), -96.0 (t,
para F), -150.5 (s, BF4). IR (KI, ν (cm-1)): 2327, 2299 (w,
CtN); 1099 (sbr, BF4). MS (FAB, m/z (%)): 645 (20) [M -
2CH3CN,BF4,BF3]+, 626 (100) [M - 2CH3CN,2BF4]+.
Dip h en yl(3-p h osp h in op r op yl)p h osp h in e (8). A solution
of diisopropyl 3-(diphenylphosphino)propylphosphonate (7)
(23.12 g, 58.8 mmol) in ether (100 mL) was added slowly to a
suspension of LiAlH4 (4.5 g, 118 mmol) in ether (150 mL) at 0
°C. The reaction mixture was stirred for a further 30 min at
0 °C and overnight at room temperature. The suspension was
hydrolyzed at 0 °C. Further water was added until the
precipitated salt agglomerated. The organic phase was sepa-
rated and the residue extracted with ether. The combined
organic layers were washed with water, dried, and evaporated
to give 8 as a colorless, air-sensitive oil.
AFC7S single-crystal diffractometer at 193(2) K using Mo KR
radiation (graphite monochromator), λ ) 0.71073 Å (ω-scans).
Intensities were corrected for Lorentz and polarization ef-
fects.30 A ψ-scan absorption correction was performed.31 In 2a
a decay correction of 5.5% was made. The structure 2a was
solved by Patterson technique and subsequent Fourier analy-
ses, SHELX-97.32 Non-hydrogen atoms were refined anisotro-
pically, except fluorine atoms, with a site occupation factor
0.25, which were refined isotropically. Fluorine atoms with a
site occupation factor of less than 1.0 were refined using DFIX
and ISOR restraints and with fixed coordinates during the
final cycles of calculations. All tetrahydrofuran molecules are
partially occupied, having a site occupation factor of 0.75.
Hydrogen atoms were refined on calculated positions. After
removing it from mother liquid the specimen loses its crystal-
line appearance and diffraction ability very soon, within 1-2
min. A special cold temperature device technique with inert
oil was needed to convey the crystals alive to the diffractome-
ter. In 2c direct methods were used. Non-H atoms were treated
anisotropically and hydrogen atoms were refined on calculated
positions. Refinement of both compounds was done by a least-
squares method based on F2 with all reflections, and the
displacement factor of the H atoms was 1.2× (or 1.5× for
methyl hydrogens) that of the host atom.32
X-ray structure determinations of 2b, 3d , 3e, and 2f were
carried out by U.T. (University of Ulm). The crystals were
mounted on glass fibers. X-ray data were collected on a STOE
IPDS instrument using graphite-monochromatized Mo KR
radiation, λ ) 0.71073 Å. Crystal data are listed in Table 1
and Supporting Information together with refinement details.
Absorption corrections (analytical method) were applied for
3d and 3e. The structures were solved by the Patterson
method.33 The atomic coordinates and anisotropic thermal
parameters of the non-hydrogen atoms were refined using F2
data.32 Hydrogen atoms were included in the final refinement
cycles in a riding mode. One of the CHCl3 molecules of
crystallization of 3e‚2CHCl3 shows some disorder.
Yield: 13.4 g (88%). 1H NMR (CDCl3): δ 7.43-7.38 (m, 4H,
Ph), 7.34-7.27 (m, 6H, Ph), 2.64 (dt, 2H, -PH2), 2.11 (t, 2H,
-CH2P(Ph)), 1.70-1.57 (m, 4H, -CH2-CH2-P(prim)). 13C NMR
(CDCl3): δ 138.57 (d, ipso Ph), 132.65 (d, ortho Ph), 128.52 (s,
para Ph), 128.38 (d, meta Ph), 29.27 (dd, -CH2-P), 29.02 (dd,
-CH2-P′), 15.39 (dd, -CH2-). 31P{1H} NMR (CDCl3):
δ
-16.29 (s, PPh2), -137.97 (s, P(prim)). MS (CI, m/z (%)): 261
(100) [MH]+.
[3-(D i b r o m o )p h o s p h i n o )p r o p y l](d i p h e n y l)p h o s -
p h on iu m Br om id e (9). Diphenyl(3-phosphinopropyl)phos-
phine (8) (4.18 g, 16.05 mmol) was dissolved in CCl4 (180 mL)
and cooled to 10 °C. Bromine (5.13 g, 32.10 mmol) in CCl4 (20
mL) was added rapidly through a dropping funnel. After
stirring for 10 min the solvent and HBr were removed in vacuo
at about 10 °C. The resulting product was converted directly
to the desired ligands.
31P{1H} NMR (CDCl3): δ 182.91 (s, -PBr2), 59.10 (s,
-Pphosphonium).
P r op en e/CO Co- a n d Ter p olym er iza tion Exp er im en ts.
The corresponding dicationic palladium(II) complex (4a -g)
was dissolved in CH2Cl2 (150 mL) and activated by addition
of dry methanol (0.25 mL). The resulting solution was placed
in a 250 mL steel autoclave equipped with a mechanical gas
entrainment stirrer, which was charged subsequently with
propene (60 g) and with carbon monoxide up to a constant
pressure of 60 bar. After a reaction time of 21 h at 25 °C the
remaining gases were vented off. The resulting copolymer
solution was diluted with CH2Cl2 and stirred with water for 2
h. The organic phase was separated, filtered, and concentrated.
The remaining solvent was evaporated and the copolymer
dried in vacuo at 60 °C. PFP experiments were performed
according to the method described above for propene/CO
copolymerization reactions with additional ethene pulses
according to the literature procedure.3b
Crystallographic data for the structures reported in this
paper have been deposited in the Cambridge Crystallographic
Data Center: CCDC 193834 (2a ), CCDC 197101 (2b), CCDC
193835 (2c), CCDC 197102 (2f), CCDC 197100 (3d ), CCDC
197099 (3e).
Su p p or tin g In for m a tion Ava ila ble: Synthesis of 1b via
radical-induced addition of secondary phosphines and al-
lylphosphines. Preparation and characterization of allyl{bis-
[3,5-bis(trifluoromethyl)phenyl]}phosphine (12). ORTEP plot,
crystallographic data, and selected bond lengths and angles
of compounds 2c and 3d . Complete crystallographic data of
complexes 2a -c,f and 3d ,e. This material is available free of
charge via the Internet at http://pubs.acs.org.
OM0302138
P olym er An a lysis. 13C NMR of the copolymers for deter-
mination of regioregularity were recorded on a Bruker DRX
400 in CDCl3. Molecular weights and molecular weight dis-
tributions were measured by GPC in THF relative to polysty-
rene standards.
Cr ysta l Str u ctu r e Deter m in a tion s of 2a , 2b, 2c, 3d , 3e,
a n d 2f. Crystal data of the compounds 2a and 2c were
collected by M.K. (University of Helsinki) with a Rigaku
(30) TEXSAN, Single Crystal Structure Analysis Software, Version
1.6; Molecular Structure Corporation: 3200 Research Forest Dr., The
Woodlands, TX 77381, 1993.
(31) North, A. C. T.; Phillips, D. C. F.; Mathews, S. Acta Crystallogr.
1968, A24, 351.
(32) Sheldrick, G. M. SHELX-97, Program for the Solution and
Refinement of Crystal Structures; 1997.
(33) Sheldrick, G. M. SHELXS-86, Program for the Solution of
Crystal Structures; Go¨ttingen, 1986.