Syntheses and structures of bowl-shaped triarylphosphines and their palladium(II) complexes

Article abstract of DOI:10.1016/j.jorganchem.2005.06.025

Novel bowl-shaped triarylphosphines, tris(2,2″,6,6″- tetraalkyl[1,1′:3′,1″-terphenyl]-5′-yl)phosphines (TRMP: alkyl = methyl; TRIP: alkyl = isopropyl), were prepared by lithiation of the corresponding m-terphenyl bromides followed by reaction with PCl₃. X-ray crystallographic analysis revealed that the phosphorus center of TRMP is embedded in the shallow bowl-shaped cavity of 16 ? diameter and 2.1 ? depth formed by three radially extended m-terphenyl units. Its cone angle was estimated to be as large as 174°. In the crystal structure of TRIP, the depth of the cavity and cone angle increased to 3.3 ? and 206°, respectively, because of the different arrangement of the m-terphenyl units. In contrast with TRMP, which can form the mononuclear complex, PdCl ₂(TRMP)₂ (6), in the reaction with PdCl₂, treatment of TRIP (1 or 3 eq.) with PdCl₂ produced the trinuclear palladium(II) chloride complex, [(PdCl₂)₃(TRIP) ₂] (8), as a single product. X-ray crystallography established the structure of 8, where the trimer of PdCl₂ is terminated by two TRIP ligands. The formation of the different types of PdCl₂ complexes was explained in terms of the difference in the cavity shape of TRMP and TRIP.

Full text of DOI:10.1016/j.jorganchem.2005.06.025

Journal of Organometallic Chemistry 690 (2005) 4175–4183
www.elsevier.com/locate/jorganchem
Syntheses and structures of bowl-shaped triarylphosphines
and their palladium(II) complexes
*
*
Yoshiko Ohzu, Kei Goto , Hiroyuki Sato, Takayuki Kawashima
Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-0033 Tokyo, Japan
Received 14 March 2005; received in revised form 7 June 2005; accepted 23 June 2005
Available online 1 August 2005
Abstract
Novel bowl-shaped triarylphosphines, tris(2,200,6,600-tetraalkyl[1,10:30,100-terphenyl]-50-yl)phosphines (TRMP: alkyl = methyl;
TRIP: alkyl = isopropyl), were prepared by lithiation of the corresponding m-terphenyl bromides followed by reaction with
PCl3. X-ray crystallographic analysis revealed that the phosphorus center of TRMP is embedded in the shallow bowl-shaped cavity
˚
˚
of 16 A diameter and 2.1 A depth formed by three radially extended m-terphenyl units. Its cone angle was estimated to be as large as
˚
174°. In the crystal structure of TRIP, the depth of the cavity and cone angle increased to 3.3 A and 206°, respectively, because of the
different arrangement of the m-terphenyl units. In contrast with TRMP, which can form the mononuclear complex, PdCl2(TRMP)2
(6), in the reaction with PdCl2, treatment of TRIP (1 or 3 eq.) with PdCl2 produced the trinuclear palladium(II) chloride complex,
[(PdCl2)3(TRIP)2] (8), as a single product. X-ray crystallography established the structure of 8, where the trimer of PdCl2 is termi-
nated by two TRIP ligands. The formation of the different types of PdCl2 complexes was explained in terms of the difference in the
cavity shape of TRMP and TRIP.
Ó 2005 Elsevier B.V. All rights reserved.
Keywords: Phosphine ligands; Bowl-shaped molecules; Palladium; Crystallographic analysis
1. Introduction
have been investigating the stabilization of highly reac-
tive species by utilizing bowl-shaped molecules [2], and
previously designed the triarylmethane [3a], triarylsilane
[3b], and triarylgermane [3c] derivatives 1–3 (Scheme 1).
In these molecules, the radially extended m-terphenyl
units form a large cavity around the central functional-
ity. The reactive species embedded in the bowl-shaped
cavity of these molecules can be prevented from dimer-
ization or self-condensation effectively, whereas their
reactivity towards appropriate molecules is not so much
degenerated because there is a relatively large space
around the central functionality. For example, an S-
nitrosothiol bearing the Trm group (TrmSNO) was suc-
cessfully obtained as stable crystals [3a]. A bowl-shaped
silanol, TRMS-OH, undergoes no self-condensation
reaction even under the conditions where Ph3SiOH af-
fords the corresponding disiloxane, Ph3SiOSiPh3, while
it can readily react with trimethylsilanol generated in situ
The molecular design of sterically demanding tertiary
phosphines has been attracting increasing attention [1].
By modulating their steric bulkiness, the number of the
ligands introduced to the metal center can be controlled,
which leads to the facilitation of the formation of catalyt-
ically active low-coordinate species. Usually, increasing
the steric bulk of monodentate phosphines means the in-
crease of the steric congestion around the phosphorus
center. Although severe steric shielding of a metal center
by bulky phosphine ligands enables the control of the
coordination number, it concomitantly reduces the reac-
tivity of the complex toward substrate molecules. We
*
Corresponding authors. Tel.: +81 3 5841 4340; fax: +81 3 5800 6899.
E-mail addresses: goto@chem.s.u-tokyo.ac.jp (K. Goto), takayuki@
chem.s.u-tokyo.ac.jp (T. Kawashima).
0022-328X/$ - see front matter Ó 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2005.06.025

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Y. Ohzu et al. / Journal of Organometallic Chemistry 690 (2005) 4175–4183
with PCl3 in 92% yield (Scheme 2). For preparation of
TRIP, the use of t-butyllithium instead of n-butyllithium
for lithiation of bromide 5 [8] gave better results,
although the yield was moderate. Usually, the com-
pounds composed of oligophenylene units show poor
solubility, which is one of the largest problems of such
kind of aromatic compounds. By contrast, both TRMP
and TRIP were soluble in various solvents such as chlo-
roform, benzene, and hexane. This is probably due to
the dendritic structure of these phosphines. The 31P
NMR (CDCl3) spectra of TRMP and TRIP showed
the signals at dP ꢀ7.16 and ꢀ6.60, respectively, which
are almost the same as that of PPh3 (dP ꢀ6.0) [9]. In
the 1H NMR (CDCl3) spectrum of TRMP at room tem-
perature, a single methyl signal was observed. Similarly,
TRIP showed the signals for only one kind of isopropyl
group: two nonequivalent methyl signals and one
methine signal, which was similar to m-terphenyl bro-
mide 5. These results indicate the rapid rotation of the
P–C bonds of TRMP and TRIP on the NMR time scale,
in spite of their seemingly congested structures.
Scheme 1.
to produce the corresponding condensation product
(Scheme 1) [3b]. A germanol bearing the similar frame-
work, TRMG-OH, was also found to be extremely resis-
tant to self-condensation [3c].
If the central atom of these molecules is replaced by a
phosphorus atom, very bulky phosphine ligands without
severe steric congestion in the vicinity of the phosphorus
center are expected to be obtained. Recently, Tatsumi
and co-workers [4] and our group [5] independently re-
ported the synthesis of a bowl-shaped triarylphosphine,
tris(2,200,6,600-tetramethyl[1,10:30,100-terphenyl]-50-yl)pho-
sphine (denoted as TRMP, Fig. 1). We have also com-
municated the application of TRIP, in which the methyl
groups of TRMP are replaced by isopropyl groups [6].
Herein, we report the syntheses and full characterization
of these bowl-shaped phosphines and their palladium(II)
complexes including the first example of the
[(PdX2)3(PR3)2]-type trinuclear complex.
2.2. Crystal structures of TRMP and TRIP
The structures of TRMP and TRIP were established
by X-ray crystallographic analysis. ORTEP drawings
are shown in Fig. 2 with the selected bond lengths and
ꢀ
angles. The structure of TRMP belongs to the P3 trigo-
nal space group, where the number of molecules in the
asymmetric unit is 1/3. The m-terphenyl groups are ar-
ranged in a propeller shape, and the dihedral angle be-
tween the aromatic ring attached to the phosphorus
atom and the plain containing the C3 axis and the P–C
bond is 52.7° (Fig. 3). The phosphorus atom of TRMP
is embedded in a shallow bowl-type cavity with a diam-
˚
eter of ca. 16 A as shown in Fig. 4. There is a relatively
large space without any alkyl substituent around the
phosphorus center. The cone angle of TRMP is esti-
mated to be 174°, which is comparable with that of
tri-t-butylphosphine (182°) and much larger than that
of PPh3 (145°) [9]. On the other hand, the C–P–C bond
angle of TRMP is 102.61(6)°, which is almost the same
as that of triphenylphosphine (103°) in contrast to other
bulky phosphines such as P(Mes)3 (110°) [10] and
P(Tip)3 (Tip = 2,4,6-triisopropylphenyl) (112°) [11].
2. Results and discussion
2.1. Syntheses of triarylphosphines TRMP and TRIP
TRMP was prepared by lithiation of m-terphenyl
bromides 4 [7] with n-butyllithium followed by reaction
Fig. 1. Bowl-shaped phosphines bearing m-terphenyl units.
Scheme 2.

Y. Ohzu et al. / Journal of Organometallic Chemistry 690 (2005) 4175–4183
4177
Fig. 4. Space-filling models of the crystal structures of TRMP and
TRIP.
and 3, the silicon and germanium analogues of TRMP;
the averaged C–Si–C and C–Ge–C angles of the silanol
(2, X = OH) [3b] and the germanol (3, X = OH) [3c] are
109° and 111°, respectively, which are almost the same
as those of Ph3SiOH (110°) [12] and Ph3GeOH (112°)
[13].
ꢀ
TRIP crystallizes in the P1 triclinic space group,
Fig. 2. ORTEP drawings of (a) TRMP and (b) TRIP (50% probabil-
ity). Selected bond lengths (A) and angles (°) for (a): P(1)–
C(1),1.8329(16); C(1)–P(1)–C(1)*, 101.61(6). For (b): P(1)–C(1),
1.829(3); P(1)–C(2), 1.830(3); P(1)–C(3), 1.836(3); C(1)–P(1)–C(2),
101.52(13); C(2)–P(1)–C(3), 103.48(13); C(1)–P(1)–C(3), 104.52(13).
where the asymmetric unit contains one molecule of
TRIP and two molecules of chloroform. Although the
diameter of TRIP is almost the same as that of TRMP,
˚
˚
the depth of the cavity increases from 2.1 A in TRMP to
˚
3.3 A in TRIP (Fig. 4). This increase in the depth in
TRIP is mainly caused by the arrangement of the m-ter-
phenyl units. The dihedral angles between the aromatic
ring attached to the phosphorus atom and the plain con-
taining the pseudo C3 axis and the P–C bond are 22.0°,
24.0°, and 29.7° (av. 25°) (Fig. 3), which are much smal-
ler than that of TRMP. Such a vertical arrangement of
the m-terphenyl units in TRIP is likely to minimize the
steric repulsion among the bulky isopropyl groups in
the bottom side of the molecule. Because of such struc-
tural changes, the cone angle of TRIP is much enlarged
in comparison with TRMP. It is estimated to be 206°,
which is even larger than that of P(t-Bu)3. In spite of
such enlargement of the cone angle, however, the aver-
aged C–P–C bond angle of TRIP (103°) is almost the
same as those of PPh3 and TRMP. These results indicate
the characteristics of the dendrimer-type framework
again.
Fig. 3. Dihedral angles between the aromatic ring attached to the
phosphorus atom and the plain containing the (pseudo) C3 axis and
the P–C bond.
These results indicate that, in TRMP bearing a dendritic
framework, the molecular size is enlarged in comparison
with PPh3 without increasing steric repulsion among the
three m-terphenyl groups. Similar results for the C–E–C
(E = element) bond angles were found for compounds 2

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Y. Ohzu et al. / Journal of Organometallic Chemistry 690 (2005) 4175–4183
2.3. Synthesis of a palladium(II) chloride trimer complex
appeared at dP = 34.77 ppm. The structure of 8 was
determined by X-ray crystallographic analysis (vide in-
fra). Complex 8 is soluble in chloroform, dichlorometh-
ane, toluene, and acetone, but hardly soluble in ether
and ethanol. In the open atmosphere, 8 is stable both
in the solid state and in solution. It should be noted that,
even when an excess amount (3 eq.) of TRIP was used in
this reaction, only trinuclear complex 8 and unreacted
TRIP were observed in the 31P NMR spectrum of the
reaction mixture, and no other complexes were detected
(Scheme 3). The similar results were obtained when
PdCl2(PhCN)2 was used as an alternative palladium
chloride source, which is known to be in equilibrium
with [PdCl2]n [18]. Treatment of PdCl2(PhCN)2 with
TRIP (2 eq.) in refluxing benzene resulted in the forma-
tion of only complex 8 (Scheme 3). In the reactions of
tertiary phosphines thus far reported, including TRMP,
the [PdCl2(PR3)2]-type complexes were formed when an
excess of phosphine ligand was added. The present re-
sults suggest that, unlike other phosphines, only one
molecule of TRIP can be introduced to one palladium
atom because the phosphorus center of TRIP is embed-
ded in the deep bowl-shaped cavity.
The reactions of tertiary phosphines with palla-
dium(II) halides usually produce the 2:1 complexes
[PdX2(PR3)2] (X = halide) or the 2:2 complexes
[(PdX2)2(PR3)2], and bulky phosphine ligands tend to
favor the formation of 2:2 complexes [14]. However,
there has been no example of the 2:3 trinuclear complex
[(PdX2)3(PR3)2] to date probably because of the lack of
an appropriate bulky phosphine ligand. Usually,
increasing the steric bulk of a phosphine means the in-
crease of steric congestion around the phosphorus cen-
ter. The substituents in the close vicinity of the
phosphorus, however, often cause the intramolecular
cyclometallation. For example, the reactions of trimesi-
tylphosphine with palladium(II) chloride afford only the
cyclometallated dinuclear complex under a wide range
of reaction conditions [15]. Such internally metallated
complexes are of interest in view of their catalytic utility
[16], but their formation is undesirable for the synthesis
of the complex with the phosphine ligands in the intact
form. The bowl-shaped phosphines, TRMP and TRIP,
have no substituent in the ortho positions of phosphorus
that induces the cyclometallation, whereas their molecu-
lar sizes are large as a whole. It is expected that these
phosphines are useful for the control of the number of
the coordinated ligands on the metal center without
intramolecular side reactions. However, Tatsumi et al.
[4a] reported that, even in the case of TRMP, the reac-
tions with PdCl2 in the ratio of 1:2 and 1:1 (Pd/ligand)
yielded the corresponding mononuclear complex,
[PdCl2(TRMP)2] (6), and the dinuclear complex,
[(PdCl2)2(TRMP)2] (7), respectively. These results
prompted us to examine the reaction of TRIP with
PdCl2. Although based only on indirect evidence, there
have been several reports about the formation of a
PdCl2 trimer terminated by organic ligands at each
end [17]. On the other hand, there has been no example
of the characterization of a PdCl2 trimer complex bear-
ing phosphine ligands, [(PdCl2)3(PR3)2].
2.4. Structures of palladium(II) complexes
The yellow single crystals of [(PdCl2)3(TRIP)2] (8)
suitable for X-ray crystallographic analysis were ob-
tained by recrystallization from CHCl3, and its structure
was established by X-ray crystallographic analysis. The
ORTEP drawings and space-filling model of 8 are
shown in Fig. 5 with the selected bond lengths and an-
gles, and the comparison of the bond lengths with those
of related complexes is shown in Table 1. This is the first
structural analysis of a PdCl2 trimer complex although
the crystal structures of several p-allyl complexes with
a Pd3Cl4 bridge such as 10–12 have been reported [19–
21].
ꢀ
The structure of 8 Æ 10CHCl3 belongs to the the P1
triclinic space group, which contains three Pd atoms
linked by bridging chloride ligands with the Pd(2) atom
residing at a crystallographic inversion center. The sol-
vent molecules (omitted for clarity in Fig. 5) are located
outside the cavity of the TRIP ligand. It is known that in
the crystal structure of PdCl2 the bridging chlorines
form an infinite polymeric ribbon [18]. The structure
of 8 can be regarded as a PdCl2 trimer cut out from
the polymeric chain of [PdCl2]n by two phosphine li-
gands. The space-filling model (Fig. 5(b)) shows that
the trimer of PdCl2 is encapsulated by two TRIP ligands
bearing a deep cavity. This figure also suggests that the
formation of the isomer of 8 with two TRIP ligands in
the cis positions would be sterically difficult. The bond
length of Pd(1)–Cl(3) is substantially longer than that
of Pd(1)–Cl(1), indicating that the trans influence of
the phosphine ligand is stronger than that of the
When PdCl2 was treated with an equimolar amount
of TRIP in refluxing ethanol/THF, the trinuclear palla-
dium(II) chloride complex, [(PdCl2)3(TRIP)2] (8), was
obtained as a single product (Scheme 3). The 1H
NMR spectrum (CDCl3) of the crude product revealed
that the reaction proceeded almost quantitatively. In
the 31P NMR spectrum (CDCl3), the signal of 8
Scheme 3.

Y. Ohzu et al. / Journal of Organometallic Chemistry 690 (2005) 4175–4183
4179
Fig. 5. Crystal structure of 8. (a) ORTEP drawing (50% probability), (b) space filling model, and (c) ORTEP drawing of partial structure (50%
˚
probability). Selected bond lengths (A) and angles (°): Pd(1)–Cl(1), 2.3389(14); Pd(1)–Cl(2), 2.2782(14); Pd(1)–Cl(3), 2.4214(15); Pd(1)–P(1),
2.2249(14); Pd(2)–Cl(1), 2.2901(14); Pd(2)–Cl(3), 2.3054(14); P(1)–Pd(1)–Cl(3), 176.26(5); Cl(1)–Pd(1)–Cl(2), 176.48(5).
˚
chloride. Similar asymmetry in the Pd–Cl bond lengths
due to the trans influence has also been reported for
many dinuclear palladium chloride phosphine com-
plexes, such as [(PdCl2)2(PPh3)2] (9) [22] (Table 1). Con-
cerning the internal four-membered rings, there is no
significant difference between the Pd(2)–Cl(1) and
Pd(2)–Cl(3) distances, both of which are close to the
Pd–(l-Cl) bond lengths in the central PdCl4 unit of the
chloride-bridged trinuclear palladium(II) complexes
10–12 (2.29–2.31 A) [19–21] as well as the Pd–Cl bond
˚
length of [PdCl2]n (2.31 A) [23] (Table 1).
1
The H NMR spectrum of 8 in CDCl3 at room tem-
perature showed the signals for only one kind of isopro-
pyl group, which is the same signal pattern as those of
TRIP and m-terphenyl bromide 5 (Fig. 6). These results
indicate that in this complex the P–C bonds of the TRIP
ligands as well as the P–Pd bonds are rotating rapidly on
the NMR time scale in spite of the seemingly congested

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Y. Ohzu et al. / Journal of Organometallic Chemistry 690 (2005) 4175–4183
Table 1
˚
Selected bond lengths (A) for the PdCl2 complexes and related complexes
Complex
Pd–Cl
Pd–P
Reference
This work
Central PdCl4
trans to Cl
trans to P
Terminal PdCl
2.2782(14)
8
2.2901(14)
2.3054(14)
2.3389(14)
2.4214(15)
2.2249(14)
9
2.339
–
2.426
–
2.266
–
2.241
–
[22]
[23]
[PdCl2]n
2.31
10
11
12
2.313(9)
2.297(9)
–
–
–
–
–
–
–
–
–
–
–
–
[19]
[20]
[21]
2.297(1)
2.286(2)
2.300(2)
2.308(2)
structure, and that the space around the phosphorus
center of 8 is large enough to ensure the rapid rotation
of these bonds.
resides at a crystallographic inversion center. The Pd–P
bond lengths are close to that of [PdCl2(PPh3)2] (13)
(Table 2). Although the TRMP ligand has a bowl-shaped
For comparison, the palladium(II) mononuclear com-
plex bearing TRMP ligands, [PdCl2(TRMP)2] (6), was
prepared. The synthesis of 6 was first reported by Tats-
umi et al. [4a] although the details of the experimental
procedures were not described. The crystal structure of
6 is shown in Fig. 7, and the selected bond lengths and
angles are summarized in Table 2. The palladium atom
Fig. 7. ORTEP drawing of PdCl2(TRMP)2 (6) (50% probability).
Table 2
˚
Selected bond lengths (A) and angles (°) of [PdCl2(phosphine)2]
complexes
Complex
Pd–Cl
Pd–P
P–Pd–Cl Reference
[PdCl2(TRMP)2] (6) 2.2859(9) 2.3247(8) 93.23(3), This work
86.77(3)
92.0(1)
Fig. 6. 1H NMR spectrum (500 MHz, CDCl3) of [(PdCl2)3(TRIP)2]
(8).
[PdCl2(PPh3)2] (13)
2.290(1)
2.337(1)
[24]

Y. Ohzu et al. / Journal of Organometallic Chemistry 690 (2005) 4175–4183
4181
framework, its brim is ‘‘chipped’’ as shown in Fig. 4.
4.1. Synthesis of tris(2,200,6,600-tetramethyl[1,10:30,100-
terphenyl]-50-yl)phosphine (TRMP)
Because of these chips, two TRMP ligands can be in gear
with each other and coordinate to one palladium atom in
complex 6. The comparison of the structures of the trinu-
clear complex 8 and the mononuclear complex 6 indicate
that the deeper bowl-shaped cavity with a full brim of the
TRIP ligand suppressed its coordination to the same pal-
ladium atom and enabled the formation of the
[(PdX2)3(PR3)2]-type complex.
n-Butyllithium (1.53 M hexane solution, 5.36 mmol)
was added to a solution of m-terphenyl bromide 4
(1.83 g, 5.01 mmol) in THF (30 mL) at ꢀ70 °C. The mix-
ture was stirred at ꢀ70 °C for 25 min. PCl3 (150 lL, 1.72
mmol) was added to this solution and the mixture was
stirred at ꢀ70 °C for 2 h and at room temperature for
2 h. After removal of the solvent, the residue was treated
with degassed H2O, and extracted with degassed CHCl3
under argon. The extracts were dried over anhydrous
MgSO4. After removal of the solvent under reduced
pressure, the residue was washed thoroughly with
degassed ethanol to give TRMP as colorless crystals
3. Conclusion
Novel bowl-shaped triarylphosphines, TRMP and
TRIP, where the radially extended m-terphenyl units
form a large cavity, were synthesized and fully charac-
terized. Whereas the cone angles of TRMP and TRIP
were estimated to be as large as 174° and 206°, respec-
tively, there is a large and inert space around their
phosphorus center because of the absence of any substi-
tuent in the ortho positions of phosphorus. The reac-
tion of TRIP, which has a deeper bowl-shaped cavity,
with PdCl2 produced the trinuclear palladium(II) chlo-
ride complex, [(PdCl2)3(TRIP)2] (8), as a single product,
presenting the first example of a structurally character-
ized PdCl2 trimer complex. These bowl-shaped phos-
phines are expected to work as potent ligands in
catalytic reactions. Recently, Tsuji et al. [25] utilized
TRMP for the efficient rhodium-catalyzed hydrosilyla-
tion of ketones. Investigations on the reactivity of the
metal complexes bearing TRMP and TRIP are cur-
rently in progress.
1
(1.41 g, 92%). M.p. 284–287 °C. H NMR (500 MHz,
CDCl3) d 1.86 (s, 36H), 6.87 (s, 3H), 7.01–7.13 (m,
24H). 31P NMR (109 MHz, CDCl3) d ꢀ7.16. 13C{1H}
NMR (126 MHz, CDCl3) d 20.67 (s), 127.05 (s),
127.17 (s), 130.21 (s), 132.52 (d, JPC = 18.9 Hz), 135.65
(s), 137.78 (d, JPC = 13.1 Hz), 141.20 (s), 141.64 (d,
JPC = 6.9 Hz). APCI-MS m/z 888 [M + H]+.
4.2. Synthesis of tris(2,200,6,600-tetraisopropyl[1,10:30,100-
terphenyl]-50-yl)phosphine (TRIP)
tert-Butyllithium (2.36 M hexane solution, 6.14
mmol) was added to a solution of m-terphenyl bromide
5 (1.42 g, 2.97 mmol) in THF (25 mL) at ꢀ70 °C. The
mixture was stirred at ꢀ70 °C for 25 min. PCl3 (84
lL, 0.963 mmol) was added to this solution and the mix-
ture was stirred at ꢀ70 °C for 2.5 h and at room temper-
ature for 2 h. After removal of the solvent, the residue
was treated with degassed H2O, and extracted with de-
gassed CHCl3 under argon. The extracts were dried over
anhydrous MgSO4. After removal of the solvent under
reduced pressure, the residue was washed thoroughly
with degassed ethanol to give TRIP as colorless crystals
(0.475 g, 40%). M.p. 345 °C. 1H NMR (500 MHz,
CDCl3) d 0.77 (d, JHH = 6.8 Hz, 36H), 0.95 (d,
JHH = 6.8 Hz, 36H), 2.52 (sept, JHH = 6.8 Hz, 12H),
6.97 (s, 3H), 7.10 (d, JHH = 7.8 Hz, 12H), 7.26 (t,
JHH = 7.8 Hz, 6H), 7.50 (dd, JPH = 8.7 Hz, JHH = 1.6
Hz, 6H). 31P NMR (109 MHz, CDCl3) d ꢀ6.60.
13C{1H} NMR (126 MHz, CDCl3) d 23.60 (s), 23.99
(s), 30.38 (s), 122.41 (s), 127.91 (s), 131.58 (s), 133.45
(d, JPC = 23.2 Hz), 135.60 (d, JPC = 13.7 Hz), 138.77
(s), 140.61 (d, JPC = 8.6 Hz), 146.61 (s). Anal. Calc.
for C90H113OP: C, 87.05; H, 9.17. Found: C, 86.89; H,
9.27%. APCI-MS m/z 1224 [M + H]+.
4. Experimental
All reactions were carried out under argon atmo-
sphere with standard Schlenk or vacuum line techniques.
Melting points were determined on a Yanaco micro melt-
ing point apparatus. All melting points were uncor-
rected. THF was purified by distillation from sodium
diphenylketyl under argon atmosphere before use. Chlo-
roform-d was distilled from calcium hydride before use.
Phosphorus trichloride was distilled from calcium hy-
dride before use. The 1H NMR (500 MHz) and 13C
NMR (126 MHz) spectra were measured with a Bruker
Avance500 spectrometer and a Bruker DRX-500 spec-
trometer using a residual peak of deuterated solvents as
an internal standard. The 31P NMR (109 MHz) spectra
were measured with a JEOL Excalibur270 spectrometer
using 85% H3PO4 as an external standard. Atmospheric
pressure chemical ionization (APCI) mass spectra were
recorded with a Shimadzu LC-MS-QP 8000a spectrome-
ter. Elemental analyses were performed by the Microan-
alytical Laboratory of the Department of Chemistry,
Faculty of Science, The University of Tokyo.
4.3. Synthesis of [PdCl2 (TRMP)2] (6)
A solution of TRMP (282.6 mg, 0.319 mmol) in THF
(15 mL) was added to a solution of PdCl2 (15 mg,
0.0846 mmol) in ethanol (10 mL) at room temperature.

4182
Y. Ohzu et al. / Journal of Organometallic Chemistry 690 (2005) 4175–4183
The mixture was refluxed for 3 h. After removal of the
solvent, the residue was treated with CHCl3 and filtered.
After evaporation of the solvent, the residue was recrys-
tallized from CHCl3/hexane to give [PdCl2(TRMP)2] (6)
as yellow crystals (148.8 mg, 90%). M.p. 335 °C (dec).
1H NMR (500 MHz, CDCl3) d 1.75 (s, 72H), 6.89 (s,
6H), 6.97 (d, JHH = 7.6 Hz, 24H), 7.07 (t, JHH = 7.6
Hz, 12H), 7.46 (m: virtual coupling, 12H). 31P NMR
(109 MHz, CDCl3) d 22.47. 13C{1H} NMR (126
MHz, CDCl3) d 20.69 (s), 127.06 (s), 127.16 (s),
130.34 (m: virtual coupling), 131.92 (s), 133.69 (m: vir-
tual coupling), 135.84 (s), 140.67 (s), 140.91 (m: virtual
coupling).
(126 MHz, CDCl3) d 23.64 (s), 24.02 (s), 30.31(s),
122.65 (s), 126.72 (d, JPC = 57 Hz), 128.10 (s), 133.72
(brs), 134.15 (s), 137.78 (s), 140.77 (m: virtual cou-
pling), 146.80 (s). Anal. Calc. for C180H222Cl6P2Pd3:
C, 72.56; H, 7.51. Found: C, 72.27; H. 7.79%. In the
reaction of TRIP (133.0 mg, 0.109 mmol) with
PdCl2(PhCN)2 (21 mg, 0.055 mmol) in benzene (15
mL) at reflux temperature for 2 h, the 31P NMR spec-
trum of the reaction mixture showed only the signals of
complex 8 and TRIP.
4.5. X-ray crystallographic analysis of TRMP, TRIP, 6,
and 8
4.4. Synthesis of [(PdCl2)3 (TRIP)2] (8)
Single crystals of TRMP Æ 1.5THF were grown from
its THF/hexane solution at room temperature under
argon atmosphere. Single crystals of TRIP Æ 2CHCl3
were grown from its CHCl3 solution at ꢀ20 °C under ar-
gon atmosphere. Single crystals of 6 Æ 4CHCl3 and
8 Æ 10CHCl3 were grown from their CHCl3 solution at
room temperature in the open atmosphere. The intensity
data were collected on a Rigaku/MSC Mercury CCD
diffractometer with graphite-monochromated Mo Ka
A solution of TRIP (134.9 mg, 0.110 mmol) in THF
(30 mL) was added to a solution of PdCl2 (29.8 mg,
0.168 mmol) in ethanol (10 mL) at room temperature.
The mixture was refluxed for 3 h. After removal of
the solvent, the residue was treated with CHCl3 and fil-
tered. After evaporation of the solvent, the residue was
washed with hexane and recrystallized from CHCl3/
hexane to give [(PdCl2)3(TRIP)2] (8) as yellow crystals
(80.3 mg, 49%). M.p. 380 °C (dec). 1H NMR (500
MHz, CDCl3d) 0.69 (d, JHH = 6.8 Hz, 72H), 0.89 (d,
JHH = 6.8 Hz, 72H), 2.53 (sept, JHH = 6.8 Hz, 24H),
7.07 (d, JHH = 7.8 Hz, 24H), 7.10 (s, 6H), 7.29 (t,
JHH = 7.8 Hz, 12H), 7.76 (d, JPH = 9.3 Hz, 12H). 31P
NMR (109 MHz, CDCl3) d 34.77. 13C{1H} NMR
˚
radiation (k = 0.71069 A). The structures were solved
by the direct method and refined by full-matrix least-
squares on F2 using SHELXL-97 [26]. The non-hydrogen
atoms were refined anisotropically. The hydrogen atoms
were idealized by using the riding models. Crystallo-
graphic data for TRMP Æ 1.5THF, TRIP Æ 2CHCl3,
6 Æ 4CHCl3, and 8 Æ 10CHCl3 are listed in Table 3.
Table 3
Crystallographic data for TRMP Æ 1.5THF, TRIP Æ 2CHCl3, 6 Æ 4CHCl3, and 8 Æ 10CHCl3
TRMP Æ 1.5THF
TRIP Æ 2CHCl3
6 Æ 4CHCl3
8 Æ 10CHCl3
Formula
Formula weight
T (K)
C72H75O1.5
995.29
120
P
C92H113Cl6P
1462.49
120
C136H130Cl14P2
2429.04
120
C190H232Cl36P2P
4173.10
120
Crystal system
Trigonal
Triclinic
Monoclinic
P21/n
14.071(5)
29.425(11)
16.724(7)
90
117.548(4)
90
6139(4)
2
Triclinic
ꢀ
ꢀ
ꢀ
Space group
P3
P1
P1
˚
a (A)
15.1903(8)
15.1903(8)
14.2841(11)
90
90
120
2854.4(3)
2
1.158
14.855(5)
14.885(4)
21.813(7)
76.152(12)
84.394(13)
67.948(10)
4340(2)
2
15.920(6)
17.486(7)
20.339(8)
82.825(16)
71.934(14)
74.785(14)
5189(4)
1
˚
b (A)
˚
c (A)
a (°)
b (°)
c (°)
3
˚
V (A )
Z
Dcalc (g cmꢀ3
)
1.119
1.314
1.336
Reflections collected
Unique reflections
Rint
19592
3324
0.0229
1068
28146
14872
0.0340
1564
37069
10192
0.0454
2520
33449
17768
0.0326
2152
F(000)
l(Mo Ka) (mmꢀ1
)
0.093
0.258
0.532
0.783
Limiting indices
ꢀ18 6 h 6 17,
ꢀ17 6 h 6 13,
ꢀ16 6 h 6 16,
ꢀ18 6 h 6 18,
ꢀ18 6 k 6 18, ꢀ16 6 l 6 13 ꢀ17 6 k 6 17, ꢀ25 6 l 6 25 ꢀ33 6 k 6 34, ꢀ19 6 l 6 19 ꢀ20 6 k 6 17, ꢀ23 6 l 6 24
Restraints/parameters 0/263
Goodness-of-fit on F2 1.058
0/971
1.096
0/733
1.096
0/1075
1.057
R indices [I > 2r(I)]
R indices (all data)
R1 = 0.0494, wR2 = 0.1465
R1 = 0.0541, wR2 = 0.1520
R1 = 0.0816, wR2 = 0.1720
R1 = 0.1051, wR2 = 0.1865
R1 = 0.0483, wR2 = 0.1117
R1 = 0.0524, wR2 = 0.1141
R1 = 0.0676, wR2 = 0.1606
R1 = 0.0905, wR2 = 0.1779

Y. Ohzu et al. / Journal of Organometallic Chemistry 690 (2005) 4175–4183
4183
(b) T. Matsumoto, T. Kasai, K. Tatsumi, Chem. Lett. (2002)
346.
5. Supplementary material
[5] (a) K. Goto, Y. Ohzu, H. Sato, T. Kawashima, in: 15th
International Conference on Phosphorus Chemistry, Sendai, July
2001, Abstr. No. PB072;
(b) K. Goto, Y. Ohzu, H. Sato, T. Kawashima, Phosphorus
Sulfur Silicon Relat. Elem. 177 (2002) 2179.
[6] Y. Ohzu, K. Goto, T. Kawashima, Angew. Chem., Int. Ed. 42
(2003) 5714.
[7] T.K. Vinod, H. Hart, J. Org. Chem. 56 (1991) 5630.
[8] K. Goto, G. Yamamoto, B. Tan, R. Okazaki, Tetrahedron Lett.
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[9] C.A. Tolman, Chem. Rev. 77 (1977) 313.
[10] J.F. Blount, C.A. Maryanoff, K. Mislow, Tetrahedron Lett.
(1975) 913.
Crystallographic data for the structural analysis has
been deposited with the Cambridge Crystallographic
Data Centre, CCDC Nos. 265230, 216987, 265231,
and 216988 for TRMP Æ 1.5THF, TRIP Æ 2CHCl3,
6 Æ 4CHCl3, and 8 Æ 10CHCl3, respectively. Copies of this
information may be obtained free of charge from the
director, CCDC, 12 Union Road, Cambridge CB2
1EZ, UK (fax: +44 1223 336 033; e-mail: deposit@ccdc.
cam.ac.jk or www: http://www.ccdc.cam.ac.uk).
[11] (a) S. Sasaki, K. Sutoh, F. Murakami, M. Yoshifuji, J. Am.
Chem. Soc. 124 (2002) 14830;
Acknowledgements
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[14] A.T. Hutton, C.P. Morley, in: G. Wilkinson (Ed.), Comprehen-
sive Coordination Chemistry, vol. 5, Pergamon Press, Oxford,
1987, p. 1157.
This work was partly supported by Grants-in-Aid for
the Scientific Research (Nos. 14703066 (K.G.), and
15105001 (T.K.)) and for the 21st Century COE Pro-
gram for Frontiers in Fundamental Chemistry (T.K.)
from the Ministry of Education, Culture, Sports, Sci-
ence and Technology of Japan. We also thank Tosoh
Finechem Corporation for the generous gifts of
alkyllithiums.
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