408 Organometallics, Vol. 27, No. 3, 2008
Szuromi et al.
1
Table 4. Summary of X-Ray Diffraction Data for
washed with pentane to give pure 3 (323.9 mg, 95%). H NMR
(CD2Cl2): δ 5.41 (m, 1H, H5), 4.53 (m, 2H, H1 and H4), 2.99 (m,
2H, H2 and H3), 2.50–1.16 (m, 66H, PCy3). 31P{1H} (CD2Cl2, 23
°C): δ 36.5 (s, PCy3), -144.2 (septet, JPF ) 710, PF6-).
[{(allyl)Pd(PCy3)}2(µ-Cl)][PF6] (1)
formula
C42H76ClF6P3Pd2
fw
1036.19
cryst syst
space group
a (Å)
orthorhombic
Pbca
17.332(2)
Polymerization of NB/MA Mixtures. A 20 mL vial was charged
with norbornene (565 mg, 6 mmol, 2.05 mL of a 2.92 M stock
solution in toluene), methyl acrylate (516 mg, 6 mmol, 0.54 mL),
toluene (3.83 mL), and (a) catalyst 1 (5.2 mg, 0.5 mL of a 0.01 M
stock solution in CH2Cl2, 5 µmol of 1, 10 µmol Pd) or (b) freshly
generated 1-in situ in CH2Cl2 (0.5 mL, 10 µmol Pd) or (c) complex
3 (4.3 mg, 5 µmol Pd, in 0.5 mL of CH2Cl2) in the drybox. The
vial was closed with a cap equipped with a rubber septum and taken
out of the drybox. The mixture was heated to 50 °C in an oil bath
and stirred for 5 h. The mixture was poured into MeOH (80 mL)
and filtered, and the pale yellow solid was dried under vacuum at
50 °C overnight ((a) 763 mg, NB/MA ) 72/28 (Table 1, run 1),
(b) 780 mg, NB/MA ) 71/29 (Table 1, run 3), and (c) 643 mg,
NB/MA ) 85/15 (Table 1, run 4)).
Homopolymerization of NB by 1-in situ. A 10 mL vial was
charged with norbornene (282 mg, 3 mmol, 0.39 mL of a 7.69 M
stock solution in toluene), toluene (2.82 mL), and freshly generated
1-in situ in CH2Cl2 (0.25 mL, 5 µmol Pd) in the drybox. The vial
was closed with a cap equipped with a rubber septum and taken
out of the drybox. The mixture was heated to 50 °C in an oil bath
and stirred for 5 h. The mixture was poured into MeOH (80 mL)
and filtered, and the pale yellow solid was dried under vacuum at
50 °C overnight (282 mg, 100%) (Table 2, run 5).
Homopolymerization of MA. Polymerization by 1-in situ: A
10 mL vial was charged with methyl acrylate (258 mg, 3 mmol,
0.27 mL), toluene (2.94 mL), and freshly generated 1-in situ in
CH2Cl2 (0.25 mL, 5 µmol Pd) in the drybox. The vial was closed
with a cap equipped with a rubber septum and taken out of the
drybox. The mixture was heated to 50 °C in an oil bath and stirred
for 5 h. The product was precipitated from MeOH (80 mL), filtered,
and dried under vacuum at 50 °C overnight to give a transparent
film (108 mg, 42%) (Table 2, run 7). Polymerization by AIBN:
The same procedure was used except that AIBN (2.46 mg, 15 µmol)
and CH2Cl2 (0.25 mL) were used instead of 1-in situ/CH2Cl2. Yield:
25.8 mg 10% (Table 3, run 9).
Polymerization of Z-MA-d1. The polymerization of a Z-MA-
d1/NB (1/1) mixture by 1-in situ, polymerization of Z-MA-d1 by
1-in situ, and polymerization of Z-MA-d1 by AIBN were performed
using the procedures described above for nondeuterated MA. The
results are given in Table 3 (runs 10–12).
Fractionation Procedure. The product from the polymerization
of an NB/MA mixture by 1-in situ (Table 1, run 3; 30 mg, NB/
MA ) 71/29) was dissolved in CHCl3 (0.8 mL) and layered with
acetone (3.5 mL) at room temperature. Acetone diffused into the
CHCl3 solution over 12 h, giving a solid and a liquid phase. Most
of the solids settled, but the liquid phase also contained suspended
fine particles. Filtration through a 0.45 µm syringe filter gave a
clear liquid phase and yellow solids. The particles trapped in the
filter were removed by dissolution in chloroform and mixed with
the rest of the solids. The filtrate was stripped under vacuum, leaving
a colorless film that was identified as pure PMA by 1H NMR. The
yellow solid fraction was found to be an NB/MA material with a
significantly decreased MA content (6 mol %). This solid was
recycled through the fractionation procedure three more times; after
the last cycle the solid fraction was pure PNB (21.0 mg). The PMA
fractions of all the fractionation cycles were combined (total 7.6
mg). The calculated weights of the PNB and PMA fractions of the
starting polymer based on the monomer composition are 21.9 mg
PNB and 8.1 mg PMA. The polymer product from Table 1, run 1,
was fractionated into pure PNB and PMA fractions using the same
procedure with >95% mass balance.
b (Å)
19.320(2)
c (Å)
27.697(4)
9274(2)
V (Å3)
Z
8
T (K)
150(2)
cryst color, habit
GOF on F2
R indices (I > 2σ(I))a
R indices (all data)a
yellow, block
1.024
R1 ) 0.0493 wR2 ) 0.1114
R1 ) 0.0782 wR2 ) 0.1256
2
2 2
a R1 ) Σ4Fo| - |Fc4/Σ|Fo|; ) [Σ[w(Fo - Fc ) ]/Σw(Fo2)2]1/2, where
w ) q[1192(Fo2) + (aP)2 + bP]-1
.
for 15 min at room temperature. A solution of PCy3 (92 mg, 0.328
mmol) in CH2Cl2 (0.5 mL) was added to the mixture. (Note: PCy3
is not soluble in acetone.) The color of the suspension turned to
grayish yellow. The mixture was stirred for 2 h and filtered through
Celite to give a clear yellow filtrate. The filtrate was concentrated
to 0.3 mL and cooled to 0 °C for 1 h, resulting in the formation of
yellow crystals, which were isolated by filtration, washed with
pentane, and dried under vacuum to give 1 (131 mg, 77%). Data
for 1: H and 13C NMR assignments are based on COSY NMR
1
and reported data for (allyl)PdCl(PCy3).11 1H NMR (acetone-d6,
23 °C): δ 5.81 (m, 2H, H5), 4.81 (br t, JHH ) 6.9, 2H, H1), 3.88
(dd, JHH ) 8.7, 14.2 Hz; 2H, H2), 3.79 (br s, 2H, H4), 3.03 (br s,
2H, H3), 2.28–1.30 (m, 66H, Cy). 13C{1H} NMR (CH2Cl2, 23 °C):
δ 118.0 (d, JCP ) 4.7, C2), 83.7 (d, JCP ) 25.6, C3), 52.4 (br s,
C1), 34.5–26.5 (PCy3). 31P{1H} (acetone-d6, 23 °C): δ 42.5 (s,
–
PCy3), -142.6 (septet, JPF ) 706, PF6 ). Anal. Calcd for
C42H76ClF6P3Pd2: C, 48.68; H, 7.39. Found: C, 48.63; H, 7.15. ESI-
MS: [{(allyl)Pd(PCy3)}2(µ-Cl)]+: calcd m/z ) 891.3, found 891.3.
X-Ray Crystallographic Analysis of [{(allyl)Pd(PCy3)}2(µ-
Cl)][PF6] (1). Crystallographic data are summarized in Table 4.
Data were collected on a Brüker-AXS APEX diffractometer with
graphite-monochromated Mo KR radiation (λ ) 0.71073 Å). The
structure was solved using direct methods and refined with full-
matrix, least-squares procedures on F2. The allyl ligands were
located disordered over two positions with refined site occupancies
of 80/20 and 64/36. Chemically equivalent atoms in the disordered
contributions were treated with equal atomic displacement param-
eters and refined with equal distance restraints to adjacent equivalent
atoms. Antibumping restraints were applied between the anion, 20%
disordered allyl ligand contributor, and cyclohexyl moieties. All
non-hydrogen atoms were refined with anisotropic displacement
parameters.Allhydrogenatomsweretreatedasidealizedcontributions.
Generation of 1-in situ. A solution of {(allyl)PdCl}2 (2) (11
mg, 30 µmol) in CH2Cl2 (1 mL) was prepared. A solution of AgPF6
(7.6 mg, 30 µmol) in CH2Cl2 (1 mL) was added, and the resulting
suspension was shaken for 1 min. A solution of PCy3 (16.8 mg, 60
µmol) in CH2Cl2 (1 mL) was added, yielding a grayish-yellow
suspension. The mixture was shaken for 1 min and filtered through
Celite to give a clear yellow filtrate containing 1-in situ.
[(allyl)Pd(PCy3)2][PF6] (3). This compound was prepared by
the method published for the corresponding BF4- salt.28 A solution
of {(allyl)PdCl}2 (2) (73.2 mg, 0.2 mmol) in CH2Cl2 (1 mL) was
prepared. A solution of AgPF6 (101.1 mg, 0.4 mmol) in CH2Cl2 (1
mL) was added, and the mixture was stirred for 30 min at 23 °C.
A solution of PCy3 (224.3 mg, 0.8 mmol) in CH2Cl2 (2 mL) was
added, and the mixture was stirred for 1 h. The mixture was filtered,
and filtrate was taken to dryness under vacuum. The product was
(28) Carturan, G.; Biasiolo, M.; Daniele, S.; Mazzocchin, G. A.; Ugo,
P. Inorg. Chim. Acta 1986, 119, 19.
Szuromi, Endre
