Synthesis of η2-phosphonioalkene-palladium(0) complexes from alkenylphosphonium halides and palladium(0) species. Structure and substitution reactions of these complexes

Article abstract of DOI:10.1021/om961043k

Treatment of Pd(dba)₂ (dba = dibenzylideneacetone) with (trans-RCH=CHPPh₃)⁺Br^- in dichloromethane afforded [Pd(trans-RCH=CHPPh₃)₂Br]⁺ (R = CO₂Et (4), CO₂Me (5), Ph (6)). As shown by the results of the X-ray diffraction, 4 adopts a distorted pentagonal geometry with two EtO₂CCH=CH(PPh₃)⁺ moieties and a bromide ligand. The C-C double bond in the EtO₂CCH=CH(PPh₃)⁺ moieties are π-bonded to the palladium(0) center and are coplanar with the bromide ligand and the metal center. Both (EtO₂CCH=CHPPh₃)⁺ moieties are oriented with the two PPh₃ groups trans to each other and the olefin carbon that is attached to PPh₃ occupying the coordination site neighboring to the bromide ligand. Treatment of trons-[R¹CH=CR²(PPh₃)]⁺Br ^- with Pd(dba)₂ in the presence of 1 equiv of PPh₃ or P(OPh)₃ gave the corresponding palladium complexes Pd[trans-R¹CH=CR²(PPh₃)](L)Br (L = PPh₃, R¹ = Ph, R² = H (3). L = PPh₃, R¹ = Me, R² = H (7); R¹ = CO₂Et, R² = H (8); R¹ = CO₂Me, R² = H (9); R¹ = H, R² = Me (10). L = P(OPh)₃, R¹ = CO₂Me, R² = H (11)) in 54-92% yields. Substitution studies showed complexes 3 and 9 react with dppe (1,2-bis-(diphenylphosphino)ethane) in dichloromethane to give [Pd(RCH=CH(PPh₃)(dppe)]⁺Br^- (R = Ph (12); R = CO₂Me (13)), but treatment of 9 and 11 with PPh₃ and P(OPh)₃, respectively, afforded only the original complexes on isolation.

Full text of DOI:10.1021/om961043k

3934
Organometallics 1997, 16, 3934-3940
Syn th esis of η2-P h osp h on ioa lk en e-P a lla d iu m (0)
Com p lexes fr om Alk en ylp h osp h on iu m Ha lid es a n d
P a lla d iu m (0) Sp ecies. Str u ctu r e a n d Su bstitu tion
Rea ction s of Th ese Com p lexes
J iun-Pey Duan, Fen-Ling Liao, Sue-Lein Wang, and Chien-Hong Cheng*
Department of Chemistry, National Tsing Hua University,
Hsinchu, Taiwan 30043, Republic of China
Received December 11, 1996X
Treatment of Pd(dba)2 (dba ) dibenzylideneacetone) with (trans-RCHdCHPPh3)+Br- in
dichloromethane afforded [Pd(trans-RCHdCHPPh3)2Br]+ (R ) CO2Et (4), CO2Me (5), Ph
(6)). As shown by the results of the X-ray diffraction, 4 adopts a distorted pentagonal
geometry with two EtO2CCHdCH(PPh3)+ moieties and a bromide ligand. The C-C double
bond in the EtO2CCHdCH(PPh3)+ moieties are π-bonded to the palladium(0) center and
are coplanar with the bromide ligand and the metal center. Both (EtO2CCHdCHPPh3)+
moieties are oriented with the two PPh3 groups trans to each other and the olefin carbon
that is attached to PPh3 occupying the coordination site neighboring to the bromide ligand.
Treatment of trans-[R1CHdCR2(PPh3)]+Br- with Pd(dba)2 in the presence of 1 equiv of PPh3
or P(OPh)3 gave the corresponding palladium complexes Pd[trans-R1CHdCR2(PPh3)](L)Br
(L ) PPh3, R1 ) Ph, R2 ) H (3). L ) PPh3, R1 ) Me, R2 ) H (7); R1 ) CO2Et, R2 ) H (8);
R1 ) CO2Me, R2 ) H (9); R1 ) H, R2 ) Me (10). L ) P(OPh)3, R1 ) CO2Me, R2 ) H (11)) in
54-92% yields. Substitution studies showed complexes 3 and 9 react with dppe (1,2-bis-
(diphenylphosphino)ethane) in dichloromethane to give [Pd(RCHdCH(PPh3)(dppe)]+Br- (R
) Ph (12); R ) CO2Me (13)), but treatment of 9 and 11 with PPh3 and P(OPh)3, respectively,
afforded only the original complexes on isolation.
In tr od u ction
of the limited number of η2-phosphonioalkene metal
complexes known and the lack of a general and conve-
nient synthetic route for the preparation of these
complexes, we started to explore the possibility of
synthesizing η2-phosphonioalkene complexes from low
oxidation state metal complexes and alkenylphospho-
nium halides via substitution reactions. The prepara-
Coordination of alkenylphosphonium cations to a pal-
ladium(0) center via the carbon-carbon double bond in
the alkenyl group were recently observed by Rubinskaya
et al.1 and by us.2 The former reported that the pal-
ladium(II) complexes Pd(PPh3)2(σ-CHdCHCOOR)X re-
arranged in benzene at 75-80 °C to η2-phosphonioal-
kene-palladium(0) complexes Pd((Ph3PCHdCHCOOR)-
(PPh3)X (1). In an attempt to prepare trans-Pd(PPh3)2-
(CHdCHPh)Br directly from the oxidative addition of
bromoalkenes to Pd(PAr3)4,3 we isolated η2-phosphonio-
alkene-palladium(0) salts [(trans-RCHdCHPAr3)Pd-
(PAr3)2]+Br- (2), with bromide as the counter anion.
Moreover, in the reaction of PhCHdCHBr with the
palladium(II) species Pd(PPh3)2(C6H4O-p-CH3)I, we ob-
served the formation of complex 3. Complex 2a (R )
Ph, Ar ) Ph) was found to be a catalyst intermediate
in the preparation of the phosphonium salt PhCHd
CH(PPh3)+Br- from â-bromostyrene and triphenylphos-
phine, using Pd(PPh3)4 as the catalyst precursor. In
addition, η2-phosphonioalkene-palladium(0) complexes
were likely involved in the catalysis of cis-trans isomer-
ization of the alkenylphosphonium salt RCHdCH-
(PAr3)+X-.
tion of complexes 2a and 3 via this route was shown to
be simple and effective.2 This success prompted us to
extend this simple substitution method to the synthesis
of other phosphonioalkene-palladium complexes. In
this paper, we describe the synthesis, structure, scope,
and substitution chemistry of these new palladium(0)
complexes.
Resu lts a n d Discu ssion
Rea ction of (RO2CCHdCHP P h 3)+Br - w ith P d -
(d ba )2. Treatment of Pd(dba)2 (dba ) dibenzylidene-
acetone) with (trans-EtO2CCHdCHPPh3)+Br-, prepared
from the reaction of PPh3 with cis-EtO2CCHdCHBr
using Pd(PPh3)4 as the catalyst,2 in dichloromethane led
Other than the palladium(0) complexes 1-3, there are
only two phosphonioalkene complexes with tungsten4
and nickel5 as the metals reported in literature. In view
X Abstract published in Advance ACS Abstracts, March 15, 1997.
(1) Rybin, L. V.; Petrovskaya, E. A.; Rubinskaya, M. I.; Kuz’mina,
L. G.; Struchkov, Y. T.; Kaverin, V. V.; Koneva, N. Y. J . Organomet.
Chem. 1985, 288, 119.
(2) Huang, C. C.; Duan, J . P.; Wu, M. Y.; Liao, F. L.; Wang, S. L.;
Cheng, C. H. Organometallics, submitted for publication.
(3) Loar, M. K.; Stille, J . K. J . Am. Chem. Soc. 1981, 103, 4174.
(4) Scordia, H.; Kergoat, R.; Kubicki, M. M.; Guerchais, J . Organo-
metallics 1983, 2, 1681.
(5) Carmona, E.; Gutie´rrez-Puebla, E.; Monge, A.; Mar´ın, J . M.;
Paneque, M.; Poveda, M. L. Organometallics 1989, 8, 967.
S0276-7333(96)01043-6 CCC: $14.00 © 1997 American Chemical Society

η2-Phosphonioalkene-Palladium(0) Complexes
Organometallics, Vol. 16, No. 18, 1997 3935
Ta ble 1. Im p or ta n t Bon d Dista n ces (Å) a n d An gles
(d eg) for [(tr a n s-EtO2CCHdCHP P h 3)2P d (Br )]+Br -
(4)
Distances
Pd(1)-Br(1)
Pd(1)-C(20)
Pd(1)-C(43)
Cl(2)-C(47)
P(1)-C(7)
P(1)-C(19)
P(2)-C(30)
P(2)-C(42)
O(2)-C(21)
O(3)-C(44)
O(4)-C(45)
C(20)-C(21)
C(42)-C(43)
2.494(2)
Pd(1)-C(19)
Pd(1)-C(42)
Cl(1)-C(47)
P(1)-C(1)
2.112(11)
2.122(10)
1.717(16)
1.794(11)
1.790(10)
1.801(13)
1.807(11)
1.164(15)
1.463(11)
1.304(16)
1.384(17)
1.418(12)
1.490(14)
2.103(11)
2.129(10)
1.746(13)
1.802(13)
1.784(8)
P(1)-C(13)
P(2)-C(24)
P(2)-C(36)
O(1)-C(21)
O(2)-C(22)
O(4)-C(44)
C(1)-C(2)
1.795(11)
1.786(9)
1.358(14)
1.209(15)
1.422(16)
1.507(14)
1.398(16)
C(19)-C(20)
C(43)-C(44)
Angles
Br(1)-Pd(1)-C(19)
C(19)-Pd(1)-C(20)
96.9(3)
39.3(4)
Br(1)-Pd(1)-C(20) 135.9(2)
Br(1)-Pd(1)-C(42)
92.8(3)
F igu r e 1. Perspective view and atom-labeling scheme for
[Pd(EtO2CCHdCHPPh3)2Br]+Br- (4).
C(19)-Pd(1)-C(42) 169.3(4)
Br(1)-Pd(1)-C(43) 130.7(3)
C(20)-Pd(1)-C(42) 131.3(4)
C(19)-Pd(1)-C(43) 132.4(4)
C(20)-Pd(1)-C(43)
C(1)-P(1)-C(7)
93.1(4)
105.0(5)
110.3(5)
108.2(5)
109.7(5)
108.6(6)
110.6(4)
117.2(8)
120.5(6)
118.8(7)
C(42)-Pd(1)-C(43)
C(1)-P(1)-C(13)
C(1)-P(1)-C(19)
C(13)-P(1)-C(19)
C(24)-P(2)-C(36)
C(24)-P(2)-C(42)
C(36)-P(2)-C(42)
C(44)-O(4)-C(45)
Pd(1)-C(19)-C(20)
Pd(1)-C(20)-C(19)
38.4(4)
112.0(5)
111.5(5)
109.7(5)
109.6(5)
109.7(5)
108.7(5)
117.8(11)
70.0(6)
to a gradual color change of the solution from red-brown
to pale yellow. From the solution, a pale yellow complex
4 with the chemical formula [Pd(EtO2CCHdCHPPh3)2-
Br]+Br- was isolated. The structure of complex 4 was
determined by single-crystal X-ray diffraction. Crystals
C(7)-P(1)-C(13)
C(7)-P(1)-C(19)
C(24)-P(2)-C(30)
C(30)-P(2)-C(36)
C(30)-P(2)-C(42)
C(21)-O(2)-C(22)
Pd(1)-C(19)-P(1)
P(1)-C(19)-C(20)
70.7(6)
Pd(1)-C(20)-C(21) 110.9(7)
C(19)-C(20)-C(21) 117.9(9)
O(1)-C(21)-O(2)
O(2)-C(21)-C(20)
Pd(1)-C(42)-C(43)
Pd(1)-C(43)-C(42)
124.5(10) O(1)-C(21)-C(20)
128.1(10)
107.4(9)
71.1(6)
70.5(6)
Pd(1)-C(42)-P(2)
P(2)-C(42)-C(43)
114.5(5)
121.0(7)
Pd(1)-C(43)-C(44) 108.1(6)
C(42)-C(43)-C(44) 117.7(10) O(3)-C(44)-O(4)
O(3)-C(44)-C(43) 124.2(12) O(4)-C(44)-C(43)
123.4(10)
112.4(10)
corresponding enantiomers) for the chemical formula
[Pd(EtO2CCHdCHPPh3)2Br]+ with a pentagonal geom-
etry. The results of the X-ray analysis indicate that the
structure of the product isolated from the reaction of
Pd(dba)2 with (EtO2CCHdCHPPh3)+Br- is isomer A.
suitable for X-ray structural analysis were grown from
dichloromethane and hexane mixture. A molecular
drawing of the complex with atom numbering scheme
is shown in Figure 1, while important bond distances
and angles are presented in Table 1. As revealed by
Figure 1, each carbon-carbon double bond in the EtO2-
CCHdCH(PPh3)+ moieties is coordinated to the metal
center in an η2 fashion. The oxidation state of the
palladium center is zero, and the complex carries a
positive charge with a bromide as the counter anion.
Interestingly, in spite of the expected strong steric
repulsion between the ligands, the olefin carbons in the
EtO2CCHdCH(PPh3)+ moieties lie essentially in the
plane constructed by the ligands and the palladium
center. Figure 2 shows the deviation of each coordina-
tion site from the least-squares plane. As a result of
the conformation of EtO2CCHdCH(PPh3)+ moieties, the
palladium center adopts a distorted pentagonal geom-
etry, although only three ligands are bonded to the
metal.
The bonding of the two (EtO2CCHdCHPPh3)+ moi-
eties in complex 4 shows remarkable stereoselectivity.
Both (EtO2CCHdCHPPh3)+ moieties are oriented with
the olefin carbon that is attached to PPh3 occupying the
coordination site neighboring to the bromide ligand.
Furthermore, both ligands use the same face of the
carbon-carbon double bond for coordinating to the
palladium center, resulting in a trans arrangement of
the two PPh3 groups and of the two COOEt moieties. It
is notable that in total there are ten possible isomers
including four enantiomeric pairs (A, C, D, E and the
Moreover, the 1H NMR spectrum of the reaction solution
shows that only isomer A was produced from the
reaction. While the exact cause is not clear, it appears
that minimization of the steric repulsion between the
ligands is the driving force for the face and orientation
selectivity of (EtO2CCHdCHPPh3)+ moieties.
The trans geometry of the (EtO2CCHdCHPPh3)+
moieties in complex 4 is the same as that of the starting
EtO2CCHdCHPPh3)+Br- salt. The P-Ph bond dis-
tances (1.79 -1.81 Å) are slightly shorter than normal
phosphorus-carbon bond in coordinated PPh3.4,6 The

3936 Organometallics, Vol. 16, No. 18, 1997
Duan et al.
average distance of 1.784 Å for the phosphorus-alkenyl
bonds, P1-C19 and P2-C42, is shorter than that of a
normal sp3 phosphorus-carbon bond, but are longer
than an ylide bond.7 The results indicate the presence
of a partial ylide character for these two bonds is due
to back-donation from the palladium(0) center to the π*
orbitals of the C-C double bonds. However, the degree
of ylide character is significantly less than that in the
previously reported phosphonioalkene-palladium com-
plexes Pd(Ph3PCHdCHCOOMe)(PPh3)I,1 [(trans-PhCHd
CHPPh3)Pd(PPh3)2]+Br- and (trans-PhCHdCHPPh3)-
Pd(PPh3)X,2 in which the bond lengths of the phospho-
rus-alkenyl bonds are in the range 1.74-1.75 Å. The
average bond length of the η2-bonded C-C double bonds,
C19-C20 and C42-C43, of 1.408 Å is slightly shorter
than the values (∼1.43 Å) for those in the aforemen-
tioned three palladium-phosphonioalkene complexes.
The observed bond distances for the phosphorus-
alkenyl bond and for the η2-bonded C-C double bonds
in complex 4 clearly indicate a lessened degree of back-
donation to each (EtO2CCHdCHPPh3)+ moiety from the
palladium center relative to that in the monophospho-
nioalkene complexes. These results, with little doubt,
are due to the fact that (EtO2CCHdCHPPh3)+ moiety
is more π-acidic than PPh3 and X-.
F igu r e 2. Deviations (Å) from the calculated least-squares
plane of atoms Pd1, Br1, C19, C20, C42, and C43. The
equation for the least-squares plane is 7.420x - 4.349y +
4.910z ) -4.4985, where x, y, and z are crystal coordinates.
tion plane are higher in energy than the three out-of-
plane d orbitals, due to repulsion by the ligands.
Consequently, the olefin ligands prefer lying in the
coordination plane to allow maximum overlap of their
π* orbitals with the in-plane d orbitals.
Similarly, the reaction of (trans-MeO2CCHdCHPPh3)+-
Br- with Pd(dba)2 in dichloromethane afforded complex
5, and the reaction of (trans-PhCHdCHPPh3)+Br- with
Pd(dba)2 in DMSO gave complex 6. Both 4 and 5 are
stable in the solid state, but slowly decompose in
chloroform solution to yield palladium metal and the
corresponding phosphonium salts. Complex 6 is less
stable and cannot be isolated in pure form. For the less
electron-withdrawing phosphonium salts, trans-CH3-
CHdCH(PPh3)+Br- and CH2)CCH3(PPh3)+Br-, no
stable product can be isolated on treating with Pd(dba)2.
The 1H NMR spectra in CDCl3 of 4 and 5 exhibit
characteristic resonances for η2-coordinated phospho-
nioalkene moieties. The resonances at δ 4.92 and 3.88
are assigned to a (near the PPh3 group) and b olefin
protons, respectively, based on the coupling constants
between the phosphorus atom and the b olefin proton
of 15.8 Hz and the a olefin proton of 12.4 Hz.17 A trans-
η2-coordinated phosphonioalkene ligand was also in
agreement with the observed coupling constant of 12.4
Hz between the a and b olefin protons.18 For complex
4, the observation of diastereotopic methylene protons
at δ 3.76 and 3.89 is due to the presence of the
asymmetric center of this complex. The 1H NMR
spectrum of complex 6 cannot be obtained in good
quality in CDCl3, but in DMSO-d6, the olefin protons
for the coordinated (PhCHdCHPPh3)+ moiety appear
at δ 3.91(dd, J ) 18.8, 11.2 Hz) and 4.28 (t, J ) 11.2
Hz), similar in pattern and coupling constants to
complexes 4 and 5.
Coordination of olefin ligands to d10 metals of the
nickel family are well-known. Most of these complexes
are distorted square planar (or trigonal planar) 16-
electron systems consisting of an olefin and two other
ligands, with the chemical formula M(olefin)LL′ (M )
Pd,8 Pt,9,10 and Ni11 ). Complexes of 16-electron systems
with the formulas M(olefin)2L and M(olefin)3 having a
distorted pentagonal12,13 and hexagonal geometry,14,15
respectively, are much less common. To the best of our
knowledge, there is still no pentagonal palladium(0)
complex formulated as Pd(olefin)2L reported in litera-
ture. The coplanar structure of the two olefin and
bromide ligands in 4 is the result of maximizing overlap
of the π* orbitals in the olefin double bonds with the
two d orbitals in the pentagonal plane.16 For a
M(olefin)2L complex, the two d orbitals in the coordina-
(6) (a) Li, C. S.; Cheng, C. H.; Liao, F. L.; Wang, S. L. J . Chem.
Soc., Chem. Commun. 1991, 710. (b)Koike, M.; Hamilton, D. H.; Wilson,
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Ber. 1977, 110, 3494. (b) Klebach, T. C.; Lourens, R.; Bickelhaupt, F.;
Stam, C. H.; Van Herk, A. J . Organomet. Chem. 1981, 210, 211. (c)
Pickering, R. A.; J acobson, R. A.; Angelici, R. J . J . Am. Chem. Soc.
1981, 103, 817. (d) Voran, S.; Blau, H.; Malisch, W.; Schubert, U. J .
Organomet. Chem. 1982, 232, C33. (e) Antonova, A. B.; Kovalenko, S.
V.; Korniyets, E. D.; J ohansson, A. A.; Struchkov, Y. T.; Ahmedov, A.
I.; Yanovsky, A. I. J . Organomet. Chem. 1983, 244, 35.
(8) (a) Ozawa, F.; Ito, T.; Nakamura, Y.; Yamamoto, A. J . Orga-
nomet. Chem. 1979, 168, 375. (b) Ito, T.; Hasegawa, S.; Takahashi, Y.;
Ishii, Y. J . Organomet. Chem. 1974, 73, 401. (c) Ukai, T.; Kawazura,
H.; Ishii, Y.; Bonnet, J . J .; Ibers, J . A. J . Organomet. Chem. 1974, 65,
253. (d) Minematsu, H.; Takahashi, S.; Hagihara, N. J . Organomet.
Chem. 1975, 91, 389. (e) Minematsu, H.; Nonaka, Y.; Takahashi, S.;
Hagihara, N. J . Organomet. Chem. 1973, 59, 395.
Syn t h esis of P d [R1CHdCR 2(P P h 3)](L)Br fr om
P d (d ba )2. The reaction of Pd(dba)2 with alkenylphos-
phonium bromide in the presence of phosphine or
phosphite is a convenient way for synthesizing mono-
phosphonioalkene-palladium(0) complexes. In a previ-
ous paper,2 we reported that the reaction of Pd(dba)2
with PhCHdCH(PPh3)+Br- and 1 equiv of PPh3 in
(9) (a) Tolman, C. A.; Seidel, W. C.; Gerlach, D. H. J . Am. Chem.
Soc. 1972, 94, 2669. (b) Cheng, P. T.; Cook, C. D.; Nyburg, S. C.; Wan,
K. Y. Inorg. Chem. 1971, 10, 2210.
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(11) Cheng, P. T.; Cook, C. D.; Koo, C. H.; Nyburg, S. C.; Shiomi,
M. T. Acta Crystallogr. 1971, B27, 1904.
(12) Howard, J . A. K.; Mitrparchachon, P.; Roy, A. J . Organomet.
Chem. 1982, 235, 375.
(13) Goddard, R.; Kru¨ger, C.; Po¨rschke, K. R.; Wilke, G. J . Orga-
nomet. Chem. 1986, 308, 85.
(14) (a) Green, M.; Howard, J . A. K.; Spencer, J . L.; Stone, F. G. A.
J . Chem. Soc., Dalton Trans. 1977, 271. (b)Green, M.; Howard, J . A.
K.; Spencer, J . L.; Stone, F. G. A. J . Chem. Soc., Chem. Commun. 1975,
449.
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London, Ser. A 1983, 386, 145. (b) Czaszar, P.; Goggin, P. L.; Mink,
J .; Spencer, J . L. J . Organomet. Chem. 1989, 379, 337.
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η2-Phosphonioalkene-Palladium(0) Complexes
Ta ble 2. Selected NMR Da ta for Com p lexes 3, 7, 8, 9, 10, a n d 11a
Organometallics, Vol. 16, No. 18, 1997 3937
Ha
Hb
Hb′
Ca
Cb
δ (ppm)
J (Hz)
δ (ppm)
J (Hz)
δ (ppm)
J (Hz)
δ (ppm)
J (Hz)
δ (ppm)
J (Hz)
3
7
3.53
3J ab ) 10.3
3.24
3J ab ) 10.3
27.17
1J P ) 80.6
61.35
2J P ) 6.1
1
2
2J aP ) 7.6
3J bP ) 19.0
2J P ) 37.6
1
1
2
3J aP ) 12.6
3J bP ) 4.4
2
2
3.03
3.66
3.66
3J ab ) 10.5
2.39
2.98
2.93
2.02
3.04
3J ab ) 10.5
2J aP ) 7.7
3J bP ) 13.3
1
1
3J aP ) 15.9
3J bP ) 0
2
2
8
3J ab ) 10.2
3J ab ) 10.2
27.06
27.15
37.63
29.71
1J P ) 79.0
48.71
48.50
51.36
49.34
2J P ) 6.8
1
2
2J aP ) 9.2
3J bP ) 16.4
2J P ) 42.2
2J P ) 1.8
1
1
2
1
3J aP ) 13.0
3J bP ) 2.2
2
2
9
3J ab ) 9.9
3J ab ) 9.9
1J P ) 79.1
2J P ) 6.8
1
2
2J aP ) 9.6
3J bP ) 16.3
2J P ) 42.2
1
1
2
3J aP ) 12.8
3J bP ) 2.3
2
2
10b
11
2J bb′ ) 4.0
2.54
2J bb′ ) 4.0
1J P ) 66.9
2J P ) 12.9
1
2
3J bP ) 18.8
3J b′P ) 27.6
2J P ) 39.9
1
1
2
3J bP ) 4.0
3J b′P ) 4.0
2
2
3.52
3J ab ) 11.0
3J ab ) 11.0
1J P ) 81.1
2J P ) 6.7
1
2
3J aP ) 11.0
3J bP ) 16.3
2J P ) 67.4
1
1
2
3J aP ) 13.6
3J bP ) 2.1
2
2
a
b
In CDCl3 except otherwise mentioned. The solvent used for 10 is CD2Cl2.
dichloromethane led to the isolation of 3. This method
may be extended to the synthesis of other monophos-
phonioalkene-palladium(0) complexes. Thus, trans-
CH3CHdCH(PPh3)+Br-, trans-RO2CCHdCH(PPh3)+-
Br-, where R ) Et and Me, and CH2)CCH3(PPh3)+Br-
react with Pd(dba)2 in the presence of 1 equiv of PPh3
to give the palladium complexes 7-10, respectively,
with the general formula Pd[R1CHdCR2(PPh3)](PPh3)-
Br in 54-92% yields (eq 1). Similarly, treatment of Pd-
trans-(CH3)CHdC(CH3)(PPh3)+Br- did not give the
expected product on reacting with Pd(dba)2 and 1 equiv
of PPh3.
The chemical formulation and the structure of com-
plexes 7-11 are supported by microanalysis IR and
NMR data of these species (see Experimental Section).
Similar to 3, each of these complexes exhibits two 31P
NMR resonances at δ 21-28 ppm with coupling con-
stants of 4-8 Hz, in agreement with the formulation
that only two types of phosphorus atoms are in each
complex. The presence of an η2-coordinated phospho-
nioalkene moiety is evidenced by the upfield shift of the
olefin proton resonances to the range 2.0-3.7 ppm in
the 1H NMR spectra and the two olefin carbon reso-
nances to the sp3 region in the 13C NMR spectra. The
chemical shifts and coupling constants for the olefin
protons and carbons in the coordinated R1CHdCR2-
(PPh3)+ moieties of complexes 7-11 are summarized in
Table 2. Comparison of the coupling constants of 7-11
with the corresponding values of 3 leads us to conclude
that 7-11 are similar in structure to 3, i.e., the
R1CHdCR2(PPh3)+ moieties in these complexes are all
trans in geometry and the PPh3 or P(OPh)3 ligand is
trans to Ca in the R1CHdCR2(PPh3)+ moiety.
Su bstitu tion Rea ction s. Complex 3 was shown to
undergo a substitution reaction with PPh3 to yield the
bis(triphenylphosphine) complex 2. In the present
studies, the facile substitution reaction is further dem-
onstrated by the formation of a cationic dppe complex
12 by treating 3 with 1 equiv of dppe (eq 2). However,
3 does not undergo substitution with nitrogen ligands
such as bipyridine and pyridine. The degree of substi-
tution of Pd[R1CHdCR2(PPh3)](PPh3)Br depends greatly
on the alkenyl group in R1CHdCR2(PPh3)+ and on the
phosphine. For complexes 8 and 9, attempts to isolate
the bis(triphenylphosphine) cationic species by addition
of 1 equiv of PPh3 followed by precipitation with ether
led only to the isolation of starting complexes 8 and 9.
(dba)2 with 1 equiv of trans-MeO2CCHdCH(PPh3)+Br-
and 1 equiv of P(OPh)3 led to the formation of Pd(trans-
MeO2CCHdCH(PPh3)+)[P(OPh)3]Br (11). It is surpris-
ing that even the trans-CH3CHdCH(PPh3)+Br- and
CH2)CCH3(PPh3)+Br- salts gave stable products 7 and
10. As shown in the foregoing results, these two salts
did not afford isolable products on reacting with Pd-
(dba)2 alone. While complexes 8 and 9 have been
obtained from the rearrangement of the corresponding
oxidative-addition products, Pd(PPh3)(CHdCHCO2R)-
Br,1 the present substitution method offers a simple yet
efficient alternative for the preparation of these com-
pounds. From these synthetic studies, it is clear that
all disubstituted alkenylphosphonium cations interact
strongly with palladium(0) to afford stable products.
However, the trisubstituted alkenylphosphonium salt

3938 Organometallics, Vol. 16, No. 18, 1997
Duan et al.
19
(mixture of isomers, TCI) were used as purchased. Pd(PPh3)4
20
and Pd(dba)2 were prepared according to reported methods.
+
All of the alkenylphosphonium salts, trans-PhCHdCHPPh3
-
-
+
Br-, trans-CH3CHdCHPPh3+Br-, trans-CH3CHdCCH3PPh3
Br-, CH2)CCH3PPh3+Br-, trans-(EtOOC)CHdCHPPh3+Br-,
and trans-(MeOOC)CHdCHPPh3+Br- were prepared from the
reactions of triphenylphosphine with CH3CHdCHBr, CH3-
CHdCCH3Br, (mixtures of isomers), CH2)CCH3Br, cis-
(EtOOC)CHdCHBr, and cis-(MeOOC)CHdCHBr, respectively,
using Pd(PPh3)4 or Pd(OAc)2 as the catalyst.2 Pd(dba)2 was
prepared according to reported methods.20
Similarly, treatment of complex 11 with 1 equiv of
P(OPh)3 followed by addition of ether also results in the
isolation of the starting complex 11. However, treat-
ment of 9 with the chelating ligand dppe led to the
isolation of 13 in excellent yield (eq 2). The substitution
reactions of complexes 7 and 10 appear to behave
differently from the other Pd[R1CHdCR2(PPh3)](PPh3)-
Br complexes, 3, 8, and 9. Treatment of 7 with PPh3
led to, in part, the formation of the corresponding
cationic bisphosphine complex and, in part, the substi-
tution of the CH3CHdCH(PPh3)+ moiety by PPh3.
Complex 10 behaves similar to 7 on reacting with PPh3.
All of the substitution cationic products were character-
ized by microanalysis and comparison of the spectral
data with those of complex 2.
Syn th esis of [(tr a n s-(EtOOC)CHdCHP P h 3+)2P d (Br )]-
Br - (4). A round-bottom flask containing Pd(dba)2 (0.144 g,
0.250 mmol) and trans-(EtOOC)CHdCHPPh3+Br- (0.221 g,
0.500 mmol) was purged by nitrogen gas three times. To the
flask was then added dichloromethane (5 mL) by syringe, and
the solution was stirred at room temperature for 2 h. The solid
formed during the reaction was filtered off, and to the filtrate
was added ether to afford a white precipitate, which was
collected on a glass filter and was washed with ether (20 mL)
to afford the desired pure product (0.136 g, 55%). This
material was recrystallized from dichloromethane and hexane.
Spectral data and microanalysis data are as follows. 1H NMR
(400 MHz, CDCl3): δ 1.03 (t, CH3, J ) 7.0 Hz, 6 H), 3.76 (dq,
J ) 11.0 Hz, J ) 7.1 Hz, 2 H), 3.88 (dd, J ) 15.8 Hz, J ) 12.2
Hz, 2 H), 3.89 (dq, J ) 11.0 Hz, J ) 7.0 Hz, 2 H), 4.92 (t, J )
12.4 Hz, 2 H), 7.55-7.81 (m, 30 H). IR (KBr): 3012, 1696 (υ-
(CdO)), 1438, 1246, 1106, 725, 889 cm-1. MS (FAB): m/ z 907,
909 [M]+. Anal. Calcd for PdBr2P2C46H44O4‚CH2Cl2‚H2O: C,
52.57; H, 4.32. Found: C, 52.90; H, 4.57. Mp: 120-122 °C
dec.
Syn th esis of [(tr a n s-(MeOOC)CHdCHP P h 3+)2P d (Br )]-
Br - (5). To Pd(dba)2 (0.144 g, 0.250 mmol) and trans-
(MeOOC)CHdCHPPh3+Br- (0.214 g, 0.500 mmol) in a round-
bottom flask under nitrogen was added CH2Cl2 (5 mL). The
solution was then stirred at room temperature for 4 h. During
this period, the color of the solution changed gradually from
red-brown to pale yellow. The solid was filtered off, the solvent
was removed in vacuo, and the residue was then washed by
ether (ca. 10 mL) three times to give the desired pale yellow
product (0.214 g, 89%). This material was recrystallized from
dichloromethane and ether. Spectral data and microanalysis
data are as follows. 1H NMR (300 MHz, CDCl3): δ 3.30 (s,
OCH3, 6 H), 3.95 (dd, J ) 15.5 Hz, J ) 12.1 Hz, 2 H), 4.91 (t,
J ) 12.4 Hz, 2 H), 7.54-7.80 (m, 30 H). 13C{1H} NMR (75
MHz, CDCl3): δ 52.36 (OCH3), 55.30 (d, 1J PC ) 83.0 Hz), 67.02
In conclusion, we have isolated three classes of
phosphonioalkene-palladium(0) complexes, including
[Pd(R1CHdCR2PPh3)(L)2]+, Pd(R1CHdCR2PPh3)(L)Br,
and Pd(R1CHdCR2PPh3)2Br. In all of these complexes,
the olefin carbons of the R1CHdCR2(PPh3)+ moiety are
coplanar with the other ligands and the palladium
center. The stability of these three classes of complexes
depends greatly on the phosphonioalkene moiety. Of
the alkenylphosphonium bromides tested, only the
electron-withdrawing trans-RO2CCHdCH(PPh3)+Br- re-
acts with Pd(dba)2 to give stable bis(phosphonioalkene)
complex. On the other hand, most disubstituted al-
kenylphosphonium bromides react with Pd(dba)2 in the
presence of 1 equiv of L to give stable neutral mono-
phosphonioalkene complexes Pd[R1CHdCH(PPh3)](L)-
Br (L ) PPh3, P(OPh)3). The stability of the Pd[R1-
+
CHdCH(PPh3)](L)2 cation is influenced both by the
R1CHdCH(PPh3)+ moiety and L. An electron-with-
drawing substituent on the R1CHdCH(PPh3)+ moiety
in Pd[R1CHdCH(PPh3)](L)Br reduces the tendency for
the palladium complex to further react with a phosphine
ligand (L) to yield the cationic product Pd[R1CHdCH-
(PPh3)](L)2+, while an electron-donating substituent on
the R1CHdCH(PPh3)+ moiety enhances the removal of
the alkenylphosphonium group from Pd[R1CHdCH-
(PPh3)](L)Br- on addition of a phosphine ligand.
2
1
2
(d, J PC ) 6.6 Hz), 118.76 (d, J PC ) 90.0 Hz), 129.80 (d, J PC
3
) 12.7 Hz), 133.62 (d, J PC ) 10.1 Hz), 134.60, 166.73 (d, CO,
3J PC ) 14.7 Hz). 31P{1H} NMR (121 MHz, CDCl3): δ 25.77
(s). IR (KBr): 1702 (υ(CdO)), 1559, 1438, 1249, 1157, 1105,
996, 820, 724, 688 cm-1. MS (FAB): m/ z 879, 881 [M]+. Anal.
Calcd for PdBr2P2C44H40O4‚1/2CH2Cl2‚H2O: C, 52.33; H, 4.24.
Found: C, 52.50; H, 4.54. Mp: 120-122 °C dec.
X-r a y Str u ctu r e Deter m in a tion of [(tr a n s-(EtOOC)-
CHdCHP P h 3)2P d Br ]+Br - (4). A colorless and bladed crystal
with dimensions of 0.22 × 0.12 × 0.04 mm of the title
compound was selected for indexing and intensity data col-
lection on a Siemens R3m/V diffractometer using Mo KR
radiation (0.7107 Å). Axial oscillation photographs along the
three axes were taken to check the symmetry properties and
unit-cell parameters. The parameters of this data collection
are presented in Table 3. Of the 7488 reflections collected,
3177 unique reflections were considered observed (I g 3.0 σ-
(I)) after Lorentz polarization and empirical absorption cor-
rections. Correction for absorption effects was based on ψ
scans of a few suitable reflections with ø values close to 90°
using the program XEMP of the SHELXTL-Plus program
package. On the basis of the systematic absences, the space
Exp er im en ta l Section
All reactions were performed under dry nitrogen, and all
solvents were dried by standard methods. 1H and 13C NMR
experiments were performed on a Varian Gemini 300 or a
Varian Unity 400 spectrometer, while 31P NMR experiments
were carried out on a Brucker MSL-300 spectrometer, using
85% H3PO4 as an external standard. Infrared spectra were
recorded on a Bomem MB-100 spectrophotometer, while mass
spectra were obtained on a J eol J MS-D100 system. Melting
point measurements were carried on a MEL-TEMP apparatus
and are uncorrected. Microanalytical data were obtained on
a Heraeus CHN-O-RAPID instrument.
1-Bromopropene, R-bromostyrene (Aldrich), 2-bromo-2-
butene (mixture of isomers), cis-2-ethoxybromoethylene, 2-bro-
mopropene, triphenylphosphine (J anssen), and â-bromostyrene
(19) Coulson, D. R. Inorg. Synth. 1972, 13, 121.
(20) Takahashi, Y.; Ito, T.; Sakai, S.; Ishii, Y. Chem. Commun. 1970,
1065.

η2-Phosphonioalkene-Palladium(0) Complexes
Organometallics, Vol. 16, No. 18, 1997 3939
2
3
Ta ble 3. 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
129.30 (d, J PC ) 12.2 Hz), 129.39, 133.63, 134.27 (d, J PC
)
2
1
10.0 Hz), 134.31 (d, J PC ) 13.6 Hz), 135.45 (d, J PC ) 32.5
[(tr a n s-EtO2CCHdCHP P h 3+)2P d (Br )]Br - (4)
Hz), 171.87 (dd, CO, J PC ) 14.3 Hz, J PC ) 1.7 Hz). 31P{1H}
3
3
3
NMR (121 MHz, CDCl3): δ 22.99 (d, J PP ) 8.1 Hz), 26.75 (d,
chem formula C46H44Br2O4P2Pd‚ γ (deg)
(CH2Cl2)‚(H2O) V (Å3)
75.36(2)
2373.8(11)
2
1.525
2.297
295
0.0457
0.0389
3J PP ) 8.1 Hz). IR (KBr): 3047, 1697 (υ(CdO)), 1479, 1434,
1245, 1159, 1101, 750, 725, 693 cm-1
. MS (FAB): m/ z 729
fw
1089.9
Z
space group
a (Å)
P1h; triclinic
9.610(2)
15.542(4)
17.559(5)
89.32(2)
84.82(2)
F(calcd Mg m-3
)
[M - Br - 1]+. Anal. Calcd for PdBrP2C41H37O2: C, 60.80;
H, 4.60. Found: C, 60.11; H, 4.59. Mp: 150-152 °C dec.
[(tr a n s-MeO2CCHdCHP P h 3+)P d (P P h 3)(Br )] (9): prod-
uct yield, 92%. 1H NMR (400 MHz, CDCl3): δ 2.93 (ddd, J )
16.3 Hz, J ) 9.9 Hz, J ) 2.3 Hz, 1 H), 3.05 (s, OCH3, 3 H),
3.66 (ddd, J ) 12.8 Hz, J ) 9.9 Hz, J ) 9.6 Hz, 1 H), 7.22-
7.40 (m, 15 H), 7.47 (td, J ) 7.7Hz, J ) 3.2 Hz, 6 H), 7.60 (td,
J ) 7.6 Hz, J ) 1.6 Hz, 3 H), 7.89 (dd, J ) 12.4 Hz, J ) 7.2
µ (mm-1
T (K)
R
)
b (Å)
c (Å)
R (deg)
â (deg)
Rw
group was determined to be P1h. Direct methods were used to
locate most of the non-hydrogen atoms in the structure, with
the remaining atoms being found from a difference Fourier
map calculated at the final stage of structure analysis. The
final cycles of refinement, including the atomic coordinates and
anisotropic thermal parameters for all non-hydrogen atoms
and atomic coordinates and fixed isotropic thermal parameters
for the H atoms, converged at R ) 0.0457 and Rw ) 0.0389. In
the final difference map, the deepest hole was 0.52 e Å-3 and
Hz, 6 H). 13C{1H} NMR (75 MHz, CD2Cl2): δ 27.15 (dd, J PC
1
2
2
) 79.1 Hz, J PC ) 42.2 Hz), 48.50 (d, J PC ) 6.8 Hz), 50.96
1
4
(CH3), 123.49 (dd, J PC ) 88.5 Hz, J PC ) 3.6 Hz), 128.19 (d,
3J PC ) 9.2 Hz), 129.39 (d, J PC ) 11.6 Hz), 129.46, 133.68 (d,
2
4J PC ) 1.4 Hz), 134.33 (d, J PC ) 10.4 Hz), 134.35 (d, J PC
)
)
3
2
1
3
13.4 Hz), 135.48 (d, J PC ) 31.9 Hz), 172.13 (d, CO, J PC
14.1 Hz). IR (KBr): 1689 (υ(CdO)), 1434, 1217, 1145, 1100,
745, 691, 512 cm-1. MS (FAB): m/ z 715 [M - Br - 1]+. Anal.
Calcd for PdBrP2C40H35O2: C, 60.36; H, 4.43. Found: C, 59.98;
H, 4.51. Mp: 173-175 °C dec.
the highest peak 0.48 e Å-3
.
Corrections for secondary
extinction and anomalous dispersion were applied. Neutral-
atom scattering factors were used. Structure solution and
least-squares refinements were performed on a DEC VAX
4000/VLC workstation using the SHELXTL-Plus programs.21
Syn th esis of P d (tr a n s-R1CHdCR2P P h 3)(P P h 3)Br fr om
P d (d ba )2 a n d E-R1CHdCR2P P h 3+Br -. A general procedure
for the preparation of Pd(trans-R1CHdCR2PPh3)(PPh3)Br is
as follows. A round-bottom flask containing Pd(dba)2 (0.287
g, 0.500 mmol), triphenylphosphine (0.131 g, 0.500 mmol), and
trans-R1CHdCR2PPh3+Br (0.50 mmol) was purged by nitrogen
gas three times. To the system was added dichloromethane
(5 mL). The solution was then stirred at room temperature
for 3-4 h. The color of the solution changed gradually from
red-brown to deep yellow, and a small amount of black
precipitate was also produced during the reaction. The solid
was filtered off, and the solvent was removed in vacuo. The
residue was collected on a glass filter and was then washed
by ether (ca. 10 mL) three times to give the crude product.
Recrystallization from dichloromethane and ether afforded the
desired pure product. Product yields and spectral data for
these compounds are shown below.
[(CH2)C(CH3)P P h 3+)P d (P P h 3)(Br )] (10): product yield,
67%. 1H NMR (400 MHz, CD2Cl2): δ 1.79 (dd, CH3, J ) 15.4
Hz, J ) 6.6 Hz, 3 H), 2.09 (dt, J ) 18.8 Hz, J ) 4.0 Hz, 1 H),
2.60 (dt, J ) 27.6 Hz, J ) 4.0 Hz, 1 H), 7.26-7.44 (m, 15 H),
7.48 (td, J ) 7.8 Hz, J ) 3.1 Hz, 6 H), 7.60-7.64 (m, 3 H),
7.98 (dd, J ) 12.4 Hz, J ) 7.6 Hz, 6 H). 13C{1H} NMR (75
2
3
MHz, CD2Cl2): δ 21.87 (dd, CH3, J PC ) 9.0 Hz, J PC ) 4.5
Hz), 37.63 (dd, 1J PC ) 66.9 Hz, 2J PC ) 39.9 Hz), 51.36 (d, CH2,
2J PC ) 12.9 Hz), 122.83 (dd, J PC ) 85.7 Hz, J PC ) 4.2 Hz),
1
4
3
2
128.18 (d, J PC ) 9.0 Hz), 129.11, 129.18 (d, J PC ) 11.0 Hz),
2
3
133.29, 134.31 (d, J PC ) 14.4 Hz), 135.10 (d, J PC ) 9.3 Hz),
1
137.27 (d, J PC ) 29.0 Hz). 31P{1H} NMR (121 MHz, CDCl3):
3
3
δ 26.05 (d, J PP ) 4.4 Hz), 27.13 (d, J PP ) 4.4 Hz). IR (KBr):
3047, 1584, 1478, 1431, 1247, 1099, 896, 748, 704 cm-1. MS
(FAB): m/ z 671 [M
PdBrP2C39H35‚0.5CH2Cl2: C, 59.72; H, 4.57. Found: C, 58.55;
H, 4.55. Mp: 115-117 °C dec.
- Br -
1]+. Anal. Calcd for
[(tr a n s-MeO2CCH dCH P P h 3+)P d (P (OP h )3)(Br )] (11):
product yield, 80%. 1H NMR (400 MHz, CDCl3): δ 3.04 (ddd,
J ) 16.3 Hz, J ) 10.9 Hz, J ) 2.1 Hz, 1 H), 3.26 (s, OCH3, 3
H), 3.52 (dt, J ) 13.6 Hz, J ) 11.0 Hz, 1 H), 7.05-7.21 (m, 15
H), 7.48 (td, J ) 7.9 Hz, J ) 3.3 Hz, 6 H), 7.64 (td, J ) 7.4 Hz,
J ) 1.2 Hz, 3 H), 7.73 (dd, J ) 12.4 Hz, J ) 7.2 Hz, 6 H).
[(tr a n s-CH 3CHdCH P P h 3+)P d (P P h 3)(Br )] (7): product
yield, 76%. 1H NMR (400 MHz, CDCl3): δ 0.99 (dd, CH3, J )
6.1 Hz, J ) 3.8 Hz, 3 H), 2.39 (ddq, J ) 13.3 Hz, J ) 10.5 Hz,
J ) 6.1 Hz, 1 H), 3.03 (ddd, J ) 15.9 Hz, J ) 10.5 Hz, J ) 7.7
Hz, 1 H), 7.21-7.44 (m, 15 H), 7.54 (td, J ) 8.0 Hz, J ) 2.4
Hz, 3 H), 7.69-7.73 (m, 6 H), 7.89 (dd, J ) 12.2 Hz, J ) 7.4
Hz, 6 H). 13C{1H} NMR (100 MHz, CDCl3): δ 20.65 (d, CH3,
13C{1H} NMR (75 MHz, CD2Cl2): δ 29.71 (dd, J PC ) 81.1 Hz,
1
2J PC ) 67.4 Hz), 49.34 (d, 2J PC ) 6.7 Hz), 51.38 (OCH3), 121.39
3
1
4
(d, J PC ) 5.5 Hz), 122.78 (dd, J PC ) 88.9 Hz, J PC ) 6.3 Hz),
2
124.41, 129.56 (d, J PC ) 12.3 Hz), 129.58, 133.90, 134.24 (d,
1
2
3J PC ) 12.2 Hz), 30.97 (dd, J PC ) 80.4 Hz, J PC ) 34.9 Hz),
3J PC ) 10.0 Hz), 151.73, 171.72 (dd, CO, J PC ) 12.9 Hz, J PC
) 3.4 Hz). IR (KBr): 1701 (υ(CdO)), 1538, 1485, 1435, 1175,
888, 707, 697, 599, 524, 425 cm-1. MS (FAB): m/ z 763 [M -
Br - 1]+. Anal. Calcd for PdBrP2C40H35O5: C, 56.93; H, 4.18.
Found: C, 56.71; H, 4.26. Mp: 150-152 °C dec.
3
3
1
3
57.73, 124.24 (d, J PC ) 88.0 Hz), 127.63 (d, J PC ) 9.1 Hz),
128.50, 128.65 (d, J PC ) 12.2 Hz), 132.69, 133.73 (d, J PC
9.2 Hz), 133.83 (d, J PC ) 9.1 Hz), 136.16 (d, J PC ) 27.3 Hz).
IR (KBr): 3046, 1582, 1434, 1176, 1103, 932, 750, 720, 693
cm-1. MS (FAB): m/ z 671 [M - Br - 1]+. Mp: 130-132 °C
dec.
2
2
)
3
1
Syn th esis of [P d (tr a n s-R1CHdCR2P P h 3)(d p p e)]+Br -.
To Pd(dba)2 (0.287 g, 0.50 mmol) and dppe (0.50 mmol) in a
round-bottom flask under nitrogen was added CH2Cl2 (5 mL).
The solution was then stirred at room temperature for 10 min.
During this period, the color of the solution changed gradually
from red-brown to orange. Addition of (E-R1CHdCR2PPh3)+-
Br- (0.50 mmol) was followed by stirring at the same temper-
ature for 4 h. The solid was filtered, and to the filtrate was
added ether to precipitate out the product. The solvent was
filtered off, and the solid was washed with ether (ca. 10 mL)
three times to afford the pure material. The complexes
prepared according to this method and their spectral data are
as follows.
[(tr a n s-EtO2CCHdCHP P h 3+)P d (P P h 3)(Br )] (8): product
yield, 54%. 1H NMR (400 MHz, CDCl3): δ 0.82 (t, CH3, J )
7.2 Hz, 3 H), 2.98 (ddd, J ) 16.4 Hz, J ) 10.2 Hz, J ) 2.2 Hz,
1 H), 3.38 (dq, J ) 10.7 Hz, J ) 7.1 Hz, 1 H), 3.66 (ddd, J )
13.0 Hz, J ) 10.2 Hz, J ) 9.2 Hz, 1 H), 3.74 (dq, J ) 10.7 Hz,
J ) 7.1 Hz, 1 H), 7.22-7.39 (m, 15 H), 7.46 (td, J ) 7.8 Hz, J
) 3.2 Hz, 6 H), 7.59 (td, J ) 7.2 Hz, J ) 2.0 Hz, 3 H), 7.89 (dd,
J ) 12.8 Hz, J ) 7.6 Hz, 6 H). 13C{1H} NMR (75 MHz, CD2-
Cl2): δ 14.03 (CH3), 27.06 (dd, 1J PC ) 79.0 Hz, 2J PC ) 42.2 Hz),
2
2
48.71 (dd, J PC ) 6.8 Hz, J PC ) 1.8 Hz), 59.84 (CH2), 123.45
1
4
3
(dd, J PC ) 88.2 Hz, J PC ) 4.0 Hz), 128.09 (d, J PC ) 9.3 Hz),
[(tr a n s-P h CHdCHP P h 3)P d (d p p e)]+Br - (12): product
yield, 95%. 1H NMR (400 MHz, CDCl3): δ 2.05-2.44 (m, 4
H), 4.01-4.08 (m, 1 H), 4.30-4.40 (m, 1 H), 6.56 (ddd, J )
(21) Sheldrick, G. M. SHELXTL-Plus Crystallographic System,
release 4.21; Siemens Analytical X-ray Instruments: Madison, WI,
1991.

3940 Organometallics, Vol. 16, No. 18, 1997
Duan et al.
11.1 Hz, J ) 8.5 Hz, J ) 1.1 Hz, 2 H), 6.63 (ddd, J ) 9.9 Hz,
J ) 8.3 Hz, J ) 1.5 Hz, 2 H), 6.91 (td, J ) 7.9 Hz, J ) 2.0 Hz,
2 H), 6.99-7.74 (m, 34 H). IR (KBr): 1568, 1480, 1433, 1160,
840, 746, 691, 510 cm-1. MS (FAB): m/ z 869 [M - 1]+. Anal.
Calcd for PdBrP3C52H46.H2O: C, 64.51; H, 5.00. Found: C,
64.22; H, 5.13. Mp: 160-162 °C dec.
1212, 1150, 1100, 996, 748, 693 cm-1
.
MS (FAB): m/ z 851
.
[M - 1]+. Anal. Calcd for PdBrP3C48H44O2 H2O: C, 60.68; H,
4.88. Found: C, 60.26; H, 5.10. Mp: 170-172 °C dec.
Ack n ow led gm en t. We thank the National Science
Council of the Republic of China (NSC 84-2113-M-007-
041) for support of this research.
[(tr a n s-MeO2CCHdCHP P h 3)P d (d p p e)]+Br - (13): prod-
uct yield, 84%. 1H NMR (400 MHz, CDCl3): δ 2.03-2.17 (m,
1 H), 2.30-2.42 (m, 2 H), 2.56-2.72 (m, 1 H), 3.03 (s, OCH3,
3 H), 3.56 (dt, J ) 16.0 Hz, J ) 10.6 Hz, 1 H), 4.08-4.14 (m,
1 H), 6.63 (dd, J ) 10.6 Hz, J ) 7.4 Hz, 2 H), 7.10-7.17 (m, 4
H), 7.29-7.45 (m, 20 H), 7.54-7.71 (m, 9 H). 31P{1H} NMR
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
data and structure refinement details, atomic positional
parameters, complete bond distances and angles, thermal
parameters, and hydrogen positions for 4 (8 pages). Ordering
information is given on any current masthead page.
3
3
(121 MHz, CDCl3): δ 24.29 (dd, J PP ) 12.7 Hz, J PP ) 0.9
3
3
3
Hz), 43.86 (dd, J PP ) 12.7 Hz, J PP ) 7.0 Hz), 45.31 (dd, J PP
) 7.0 Hz, 3J PP ) 0.9 Hz). IR (KBr): 1678 (υ(CdO)), 1479, 1434,
OM961043K