Synthesis, characterization, and thermal stability of (η6:η1-C6H5CH2CH 2PR2)Ru(CH3)2 (R = Cy, Ph, Et)

Article abstract of DOI:10.1021/om0300070

Several new arene-phosphine ligands were synthesized and used to prepare the following series of tethered dialkylruthenium(II) complexes: (η⁶:η¹-C₆H₅CH₂CH ₂PR₂)Ru(CH₃)

Full text of DOI:10.1021/om0300070

Organometallics 2003, 22, 3059-3065
3059
Syn th esis, Ch a r a cter iza tion , a n d Th er m a l Sta bility of
(η6:η1-C6H5CH2CH2P R2)Ru (CH3)2 (R ) Cy, P h , Et)
Kayo Umezawa-Vizzini,† Ilse Y. Guzman-J imenez,‡ Kenton H. Whitmire,‡ and
T. Randall Lee*,†
Departments of Chemistry, University of Houston, 4800 Calhoun Road,
Houston, Texas 77204-5003, and Rice University, P.O. Box 1892, Houston, Texas 77251
Received J anuary 7, 2003
Several new arene-phosphine ligands were synthesized and used to prepare the following
series of tethered dialkylruthenium(II) complexes: (η6:η1-C6H5CH2CH2PR2)Ru(CH3)2, where
R ) Cy (1), Ph (2), Et (3). The structures of complexes 1 and 2 were determined by X-ray
diffraction. While complexes 1 and 2 were found to be more thermally stable than analogous
nontethered analogues, complex 3 was found to decompose at room temperature. In
preliminary studies, the use of complexes 1 and 2 as catalyst precursors for the polymeri-
zation of ethylene was examined.
In tr od u ction
oligomerize and/or polymerize olefins have been recently
developed based on group VIII-X metals such as Fe,3-9
Co,3-5,8 Rh,10 Ni,11-18 and Pd.12-14 Despite these ad-
vances, there are relatively few examples of ruthenium-
based Ziegler-Natta catalysts.19-22
Early-transition-metal alkyl complexes have been
widely studied, at least in part, because they serve as
important catalyst precursors for the polymerization of
olefins.1,2 Recent research, however, has focused on the
development of new types of Ziegler-Natta catalysts
based on late transition metals because of the antici-
pated tolerance of these metals toward polar functional
groups.3-18 In particular, several new catalysts that
Because ruthenium complexes have been shown to
exhibit a high tolerance toward polar functional groups
in the ring-opening metathesis polymerization (ROMP)
of cyclic olefins,23-28 we have been exploring the devel-
opment of ruthenium-based Ziegler-Natta polymeriza-
tion catalysts.29,30 In particular, our research has found
that the abstraction of one of the cis methyl groups of
cis-(DMPE)2RuMe2 in the presence of ethylene affords
the cation trans-[(DMPE)2RuMe(CH2dCH2)]+, which
fails to insert ethylene into the remaining Ru-methyl
bond.30 One of the major drawbacks of this system
apparently derives from the rapid isomerization of the
bidentate phosphine ligand during cation formation,
which gives rise to an inaccessible trans location of the
Ru-methyl bond relative to the coordinated ethylene
group.
* To whom correspondence should be addressed: trlee@uh.edu.
† University of Houston.
‡ Rice University.
(1) J ordan, R. F. J . Chem. Edu. 1998, 65, 285.
(2) Brintzinger, H.; Fischer, D.; Mulhaupt, R.; Rieger, B.; Waymouth,
R. Angew. Chem., Int. Ed. Engl. 1995, 34, 1143.
(3) Small, B. L.; Brookhart, M. Polym. Prepr. 1998, 39, 213. Small,
B. L.; Brookhart, M.; Bennett, A. M. J . Am. Chem. Soc. 1998, 120,
4049.
(4) Britovsek, G. J . P.; Gibson, V. C.; Kimberley, B. S.; Maddox, P.
J .; McTavish, S. J .; Solan, G. A.; White, A. J . P.; Williams, D. J . Chem.
Commun. 1998, 849.
(5) Britovsek, G. J . P.; Bruce, M.; Gibson, V. C.; Kimberley, B. S.;
Maddox, P. J .; Mastroianni, S.; McTavish, S. J .; Redshaw, C.; Solan,
G. A.; Stro¨mberg, S.; White, A. J . P.; Williams, D. J . J . Am. Chem.
Soc. 1999, 121, 8728.
(6) Small, B. L.; Brookhart, M. Macromolecules 1999, 32, 2120.
(7) Pellecchia, C.; Mazzeo, M.; Pappalardo, D. Macromol. Rapid
Commun. 1998, 19, 615.
From these observations, we concluded that it should
be possible to lock the vacant orbital cis to an alkyl
group by employing a rigid ligand system incapable of
isomerization. To this end, we have designed a family
(8) Schmidt, G. F.; Brookhart, M. J . Am. Chem. Soc. 1985, 107, 1443.
(9) Britovsek, G. J . P.; Gibson, V. C.; Spitzmesser, S. K.; Tellmann,
K. P.; White, A. J . P.; Williams, D. J . J . Chem. Soc., Dalton Trans.
2002, 6, 1159.
(10) Brookhart, M.; Volpe, A. F., J r.; Lincoln, D. M. J . Am. Chem.
Soc. 1990, 112, 5634.
(19) J ames, B. R.; Markham, L. D. J . Catal. 1972, 27, 442.
(20) Komita, S.; Yamamoto, A.; Ikeda, S. Bull. Chem. Soc. J pn. 1975,
48, 101.
(11) Wang, L.; Lu, R. S.; Bau, R.; Flood, T. C. J . Am. Chem. Soc.
1993, 115, 6999.
(12) Younkin, T. R.; Connor, E. F.; Henderson, J . I.; Friedrich, S.
K.; Grubbs, R. H.; Bansleben, D. A. Science 2000, 287, 460.
(13) J ohnson, L. K.; Killian, C. M.; Brookhart, M. J . Am. Chem. Soc.
1995, 117, 6414.
(14) Killian, C. M.; Tempel, D. J .; J ohnson, L. K.; Brookhart, M. J .
Am. Chem. Soc. 1996, 118, 11664.
(15) J ohnson, L. K.; Mecking, S.; Brookhart, M. J . Am. Chem. Soc.
1996, 118, 267.
(16) Conner, E. F.; Younkin, T. R.; Henderson, J . I.; Hwang, S.;
Grubbs, R. H.; Roberts, W. P.; Litzau, J . J . Polym. Sci., Part A 2002,
40, 2842.
(17) Preishuber-Pflugl, P.; Brookhart, M. Macromolecules 2002, 35,
6074.
(21) Nomura, K.; Warit, S.; Imanishi, Y. Macromolecules 1999, 32,
4732.
(22) Nomura, K.; Warit, S.; Yukio, I. Bull. Chem. Soc. J pn. 2000,
73, 599.
(23) Maughon, B. R.; Grubbs, R. H. Macromolecules 1997, 30, 3459.
(24) Hillmyer, M. A.; Gutierrez, E.; Grubbs, R. H. Macromolecules
1995, 28, 7256.
(25) Hillmyer, M. A.; Laredo, W. R.; Grubbs, R. H. Macromolecules
1995, 28, 6311.
(26) Grubbs, R. H. Macromolecules 1997, 30, 3978.
(27) Lynn, D. M.; Mohr, B.; Grubbs, R. H. J . Am. Chem. Soc. 1998,
120, 1627.
(28) Heather, D. M.; Grubbs, R. H. Macromolecules 1999, 32, 6917.
(29) Umezawa-Vizzini, K.; Lee, T. R. Organometallics 1997, 16,
5613.
(18) Liu, W.; Malinoski, J . M.; Brookhart, M. Organometallics 2002,
21, 2836.
(30) Umezawa-Vizzini, K.; Lee, T. R. J . Organomet. Chem. 1999,
157, 122.
10.1021/om0300070 CCC: $25.00 © 2003 American Chemical Society
Publication on Web 06/18/2003

3060 Organometallics, Vol. 22, No. 15, 2003
Umezawa-Vizzini et al.
Sch em e 1
complexes in refluxing chlorobenzene led to the replace-
ment of the cymene ligand with the phenyl moiety of
the phosphine ligand to give the tethered dichloro
complexes (η6:η1-C6H5CH2CH2PR2)RuCl2 (R ) Cy, Ph,
Et) in 60-95% yield. Alkylation of these complexes with
excess methyllithium in diethyl ether gave the targeted
dialkyl complexes (η6: η1-C6H5CH2CH2PR2)Ru(CH3)2
(R ) Cy, Ph, Et) in ∼35% yield. We found that the use
of less than 5 equiv of methyllithium led to incomplete
alkylation (e.g., monomethylated Ru side products). We
isolated pure samples of (η6: η1-C6H5CH2CH2PCy2)Ru-
(CH3)2 (1) and (η6: η1-C6H5CH2CH2PPh2)Ru(CH3)2 (2) by
use of flash chromatography through particulate Al2O3.
We were, however, unable to isolate pure samples of (η6:
η1-C6H5CH2CH2PEt2)Ru(CH3)2 (3) due to its rapid
decomposition during flash chromatography. Complexes
1-3 were soluble in CH2Cl2, benzene, and toluene and
slightly soluble in diethyl ether.
Ch a r a cter iza tion of Com p lexes 1-3. Analysis by
1H NMR spectroscopy of 1-3 in CD2Cl2 showed that the
coordinated arene exhibits three well-separated reso-
nances in the region δ 4.5-5.5 (for 1, δ 5.13 (t), 4.97
(d), 4.53 (t); for 2, δ 5.42 (t), 5.10 (d), 4.88 (t); for 3, δ
5.04 (t), 4.65 (t), 4.53 (d)). The doublets at δ -0.02 for
1, δ -0.20 for 2, and δ 0.50 for 3 correspond to the Ru-
CH3 protons coupled to the phosphine nucleus. The
coupling constants (J HP) of these doublets were 4.8, 6.0,
and 5.7 Hz for 1-3, respectively, which is consistent
with values reported for related compounds such as (η6-
C6H6)RuMe2(PPh3),33 (η6-1,3,5-C6H3Me3)RuMe2(PMe2-
Ph),33 (η6-C6Me6)RuMe2(L) (where L ) PMe3, PMePh2,
PPh3),34 and [(η6-C6Me6)RuMe(PMe3)(CO)]+.35
We performed X-ray structural analyses of crystals
of 1 and 2 generated by the slow evaporation of CH2Cl2
from concentrated solutions containing the respective
complexes. We were, however, unable to obtain crystals
of 3, despite using a variety of solvent and mixed-solvent
systems during crystallization trials. Thermal ellipsoid
plots and views perpendicular to the η6-phenyl ring for
compounds 1 and 2 are shown in Figures 1 and 2,
respectively. Selected bond distances and angles are
provided in Tables 1 and 2, respectively. The phenyl ring
and ethylene bridge of compound 1 were disordered
60:40 over two positions approximately related by a
mirror plane. In contrast, the structure of compound 2
was well ordered.
of dimethylruthenium(II) complexes containing the
unique arene-phosphine ligand, C6H5CH2CH2PR2, where
R ) Cy, Ph, Et. We specifically targeted the study of
(η6: η1-C6H5CH2CH2PR2)Ru(CH3)2 complexes because
the abstraction of a single methyl group from these
substrates would necessarily afford a vacant site cis to
the residual methyl group. Moreover, the resultant
cationic intermediates would be isolobal with those
postulated in the catalytically active [CpCoH(C2H4)-
PR3]+ olefin polymerization systems.31 Furthermore, we
believed that it might be possible to achieve stereo-
specific catalysis arising from the C1 symmetry of the
metal center in specially designed analogues.32
In this paper, we describe the synthesis and charac-
terization of a new family of complexes, (η6: η1-C6H5CH2-
CH2PR2)Ru(CH3)2, where R ) Cy (1), Ph (2), Et (3).
Through a series of thermal decomposition studies, we
then compare the thermal stabilities of these complexes
to each other and to those of known nontethered
analogues such as (η6-C6H6)RuMe2(PPh3) and (η6-1,3,5-
C6H3Me3)RuMe2(PMe2Ph).33 Furthermore, we conduct
preliminary experiments in which complexes 1 and 2
are examined for use as Ziegler-Natta catalyst precur-
sors for the polymerization of ethylene.
The Ru-C(1) and Ru-C(2) bond distances were
similar in both compounds (2.136(4) and 2.129(4) Å for
1; 2.142(4) and 2.143(4) Å for 2). These values are
comparable to those reported in the literature for
ruthenium alkyls.33,34 The bond distances from Ru to
each carbon of the coordinated arene were as follows
for 1: 2.210(8) Å, Ru-C(5); 2.240(9) Å, Ru-C(6);
2.27(1) Å, Ru-C(7); 2.268(8) Å, Ru-C(8); 2.238(6) Å,
Ru-C(9); 2.209(7) Å, Ru-C(10). The analogous dis-
tances were as follows for 2: 2.181(3) Å, Ru-C(13);
2.250(4) Å, Ru-C(14); 2.215(4) Å, Ru-C(15); 2.237(4)
Å, Ru-C(16); 2.239(3) Å, Ru-C(17); 2.262(4) Å, Ru-
C(18). In both complexes, the ruthenium metal lies
beneath the center of the coordinated arene. The
elongated Ru-carbon bonds trans to the bridge and the
Resu lts a n d Discu ssion
Syn th esis of Com p lexes 1-3. Scheme 1 illustrates
the strategy used to synthesize complexes 1-3. In the
first step, a series of new arene-phosphine ligands were
prepared by the reaction of (2-phenylethyl)magnesium
bromide with the appropriate dialkylchlorophosphines
in diethyl ether. These ligands were subsequently
treated with [(p-cymene)RuCl2]2 in refluxing benzene to
give the orange-red nontethered complexes (p-cymene)-
RuCl2(PR2CH2CH2C6H5) (R ) Cy, Ph, Et) in greater
than 90% yield. Subsequent heating of the nontethered
(31) Schmidt, G. F.; Brookhart, M. J . Am. Chem. Soc. 1985, 107,
1443.
(32) Hoveyda, A. H.; Morken, J . P. Angew. Chem., Int. Ed. Engl.
1996, 35, 1262.
(33) Bennett, M. A.; Smith, A. K. J . Chem. Soc., Dalton Trans. 1974,
233.
(34) Werner, H. Angew. Chem., Int. Ed. Engl. 1983, 22, 927.
(35) Werner, H.; Kletzin, H.; Hohn, A.; Paul, W.; Knaup, W.; Ziegler,
M. L.; Serhadli, O. J . Organomet. Chem. 1986, 306, 227.

(η6:η1-C6H5CH2CH2PR2)Ru(CH3)2
Organometallics, Vol. 22, No. 15, 2003 3061
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 1
Bond Lengths
Ru-C(1)
Ru-C(5)
Ru-C(7)
Ru-C(9)
Ru-P(1)
2.136(4)
2.210(8)
2.268(10)
2.238(6)
2.3070(11)
Ru-C(2)
Ru-C(6)
Ru-C(8)
Ru-C(10)
2.129(4)
2.240(9)
2.268(8)
2.209(7)
Bond Angles
C(1)-Ru-C(2)
C(2)-Ru-C(5)
C(2)-Ru-C(6)
C(2)-Ru-C(7)
C(2)-Ru-C(8)
C(2)-Ru-C(9)
C(2)-Ru-C(10)
C(2)-Ru-P(1)
81.20(18)
132.4(3)
163.5(2)
137.7(3)
103.9(3)
87.1(2)
C(1)-Ru-C(5)
C(1)-Ru-C(6)
C(1)-Ru-C(7)
C(1)-Ru-C(8)
C(1)-Ru-C(9)
C(1)-Ru-C(10)
C(1)-Ru-P(1)
146.4(3)
110.9(3)
90.3(3)
96.7(3)
125.7(3)
161.5(3)
90.78(11)
99.3(3)
97.68(12)
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 2
Bond Lengths
Ru-C(1)
Ru-C(13)
Ru-C(15)
Ru-C(17)
Ru-P(1)
2.142(4)
2.181(3)
2.215(4)
2.239(3)
2.263(1)
Ru-C(2)
2.143(4)
2.250(4)
2.237(4)
2.262(4)
Ru-C(14)
Ru-C(16)
Ru-C(18)
Bond Angles
C(1)-Ru-C(2)
C(1)-Ru-C(13)
C(1)-Ru-C(15)
C(1)-Ru-C(16)
C(1)-Ru-C(17)
C(1)-Ru-C(14)
C(1)-Ru-C(18)
C(2)-Ru-P(1)
81.65(16)
141.20(15)
134.13(16)
102.22(15)
91.15(15)
168.32(14)
107.44(15)
90.42(12)
C(2)-Ru-C(13)
C(2)-Ru-C(15)
C(2)-Ru-C(16)
C(2)-Ru-C(17)
C(2)-Ru-C(14)
C(2)-Ru-C(18)
C(1)-Ru-P(1)
136.25(14)
88.80(15)
102.97(17)
136.70(16)
103.09(15)
166.69(16)
92.14(11)
F igu r e 1. (A) Thermal ellipsoid plot of the complex
(η6:η1-C6H5CH2CH2PCy2)Ru(CH3)2 (1) at the 40% prob-
ability level and (B) a view perpendicular to the η6-phenyl
ring.
induced by the presence of the two-carbon bridge.
Similar distortion was observed in the related dichloro
complexes (η6:η1-C6H5(CH2)3PPh2)RuCl236 and (o-HOCH2-
η6:η1-C6H4CH2CH2PPh2)RuCl2.37 While the three ligands
(CH3, CH3, P) of compound 2 lie in an eclipsed confor-
mation relative to the coordinated arene, those of
compound 1 are either eclipsed or slightly staggered
relative to the coordinated arene, depending on the
nature of the disordered structure.
Th er m a l Sta bility of Com p lexes 1 a n d 2. We
examined the thermal stability of complexes 1 and 2
both in solution and in the solid state. Due to our
inability to purify complex 3 (vide supra) and the
unknown manner by which the impurities might influ-
ence its apparent thermal stability, we chose to exclude
complex 3 from these studies. Crystals of complex 1
were found to be stable over several months at room
temperature under an inert atmosphere. Crystals of
complex 2, however, gradually decomposed over a period
of 1 month under the same conditions. The stability of
1
the compounds in solution was monitored by H NMR
spectroscopy. Compounds 1 and 2 were dissolved in dry,
oxygen-free o-xylene-d10 in an NMR tube. The NMR
tube was then sealed under vacuum and gradually
heated to 130 °C. The concentrations of 1 and 2 were
measured by integration of the peaks due to the η6-C6H5
moiety at δ 5.12 for 1 and at δ 5.32 for 2 using C6Me6
(0.001 M) as an internal standard. When the solution
was heated for several hours, its color gradually changed
from light yellow to orange and eventually to black.
F igu r e 2. (A) Thermal ellipsoid plot of the complex
(η6:η1-C6H5CH2CH2PPh2)Ru(CH3)2 (2) at the 40% prob-
ability level and (B) a view perpendicular to the η6-phenyl
ring.
(36) Smith, P. D.; Wright, A. H. J . Organomet. Chem. 1998, 559,
141.
(37) Therrien, B.; Ward, T. R.; Pilkington, M.; Hoffmann, C.;
Gilardoni, F.; Weber, J . Organometallics 1998, 17, 330.
shortened Ru-carbon bonds adjacent to the bridge
probably arise from distortion of the coordinated arene

3062 Organometallics, Vol. 22, No. 15, 2003
Umezawa-Vizzini et al.
the new tethered arene-phosphine dialkylruthenium
complexes are more thermally stable than analogous
nontethered systems.
Attem p ted P olym er iza tion of Eth ylen e Usin g
Com p lexes 1 a n d 2 a s Ca ta lyst P r ecu r sor s. We
briefly examined the use of complexes 1 and 2 as
catalyst precursors for the Ziegler-Natta polymeriza-
tion of ethylene. Due to our inability to purify complex
3 (vide supra), we chose to exclude it from these
polymerization trials. A Fisher-Porter bottle was charged
with a solution of methylalumoxane (MAO) in toluene
under ethylene. Separately, the complexes were dis-
solved in toluene and then added to the reactor, which
led to an immediate color change in the solutions from
light yellow to slightly orange and then to yellow within
a few minutes. For both complexes, the following po-
lymerization conditions were employed: (a) pressure of
ethylene, 8.5 atm; (b) temperature, 25 and 50 °C; (c)
quantity of Ru complex, 10 and 20 µmol; (d) Ru/MAO
ratio, 1/1000 and 1/3000. Even at the highest temper-
ature and concentration of reactants, only trace amounts
of polymer were produced upon reaction for 1-2 h.
In these polymerization trials, the use of large ex-
cesses of MAO prevented a detailed analysis of the
products formed when complexes 1 and 2 were treated
with MAO. We were thus unable to determine whether
any cationic alkyl complexes were formed as intermedi-
ates. In separate studies,40 however, we have examined
the reactivity of complexes 1 and 2 with [H(Et2O)2]-
[B(3,5-C6H3(CF3)2)4].41 In the presence of CO, we
were able to isolate the cationic alkyl complexes,
[(η6:η1-C6H5CH2CH2PR2)Ru(CH3)(CO)][B(3,5-C6H3-
(CF3)2)4] (R ) Cy, Ph).40,42 The details of these synthetic
studies and an exploration of the use of the resultant
cationic alkyl complexes as olefin polymerization cata-
lysts are reported separately.
F igu r e 3. Thermal decomposition profiles of (η6:η1-C6H5-
CH2CH2PR2)Ru(CH3)2, where R ) Cy (b), Ph (9).
1
The intensities of all H NMR resonances attributed
to 1 and 2 were observed to gradually decrease with
heating over time. New resonances at δ 0.43 (s) and 7.5
(broad m) appeared after 22 h for 1 and 5 h for 2. Line
broadening over the range δ 0-3.5 was observed for
both species, perhaps suggesting the formation of
paramagnetic decomposition products. Figure 3 shows
that the decomposition of 1 and 2 exhibited first-order
1
kinetics, as measured quantitatively by H NMR spec-
troscopy. The rate constants at 130 °C were calculated
to be 2.21 × 10-2 min-1 with t1/2 ) 31 min for compound
1 and 5.75 × 10-2 min-1 with t1/2 ) 12 min for compound
2. While we were unable to characterize fully the
decomposition products, we believe that the decomposi-
tion reactions proceed via the formation of methane and
displacement of the coordinated arene, because of the
appearance of the singlet at δ 0.43 (corresponding to
free methane)38 and the broad multiplet at δ 7.5
(uncoordinated aromatic) as described above. It is
possible that the methane is generated via R-hydride
transfer from one methyl group to another and a radical
reactionsa process similar to that observed in studies
of the thermal decomposition of diethylruthenium(IV)
porphyrin complexes.39 Although we attempted to fur-
ther characterize the decomposition reactions by UV
spectroscopy, the stronger absorption band of the de-
composed products (λmax 267) overlapped that of the
starting materials (λmax ∼270) and thus prevented a
detailed analysis.
Regarding the inactivity of the cis-constrained com-
plexes toward the polymerization of olefins, Werner has
observed in similar systems ortho metalation of the
phenyl moiety attached to phosphorus,35 which would
lead in our case to a Ru benzyl product that might fail
to insert ethylene. Another possibility is that a stable
Ru alkyl olefin complex having a high energy of inser-
tion is formed in the reaction. The latter can plausibly
occur if the olefin orients in a manner that precludes
insertion (e.g., perpendicular to the alkyl group).
Con clu sion s
We have synthesized a new family of arene-phos-
phine ligands, C6H5CH2CH2PR2 (R ) Cy, Ph, Et), and
used them to prepare the corresponding ruthenium(II)
dichloride complexes, (η6: η1-C6H5CH2CH2PR2)RuCl2.
Alkylation of these complexes with methyllithium af-
forded the novel dialkyl complexes (η6: η1-C6H5CH2CH2-
PR2)Ru(CH3)2, where R ) Cy (1), Ph (2), Et (3).
Complexes 1 and 2 were thoroughly characterized by
NMR spectroscopy, X-ray crystallography, and thermal
Although the complexes (η6-C6Me6)RuMe2(L), where
L ) PMe3, PMePh2, PPh3, were reportedly isolable at
room temperature,34 separate studies showed that the
related nontethered complexes (η6-C6H6)RuMe2(PPh3)
and (η6-1,3,5-C6H3Me3)RuMe2(PMe2Ph) could not be
isolated at room temperature due to their facile decom-
position.33 Given that the structures of the last two
complexes more closely resemble the structures of 1-3,
the results presented here provide strong evidence that
(40) Umezawa-Vizzini, K.; Lee, T. R. Organometallics 2003, 22,
3066.
(38) We measured the 1H NMR spectrum of methane in o-xylene-
d
10 and observed a single resonance at δ 0.43. In 1H NMR spectroscopy,
(41) Brookhart, M.; Grant, B.; Volpe, A. F., J r. Organometallics 1992,
11, 3920.
(42) In contrast to ref 30, where the boron activator abstracts a
methide moiety, ref 35 reports that Ph3CX (X ) PF6-, BF4-) abstracts
a hydride moiety from related late-transition-metal dimethyl com-
plexes.
the singlet for ethane typically appears downfield of that for methane
by ∼0.6 ppm. See, for example: Friebolin, H. Basic One- and Two-
Dimensional NMR Spectroscopy; VCH: New York, 1993; p 52.
(39) Collman, J . P.; McElwee-White, L.; Brothers, P. J .; Rose, E. J .
Am. Chem. Soc. 1986, 108, 1332.

(η6:η1-C6H5CH2CH2PR2)Ru(CH3)2
Organometallics, Vol. 22, No. 15, 2003 3063
CH2PPh2, except for the use of 1.98 M C6H5CH2CH2MgBr
(12.16 mL, 2.4 × 10-2 mol) and diethylchlorophosphine (2.0 g,
1.6 × 10-2 mol) in dry diethyl ether (20 mL). The crude oily
residue was purified by vacuum distillation. Yield: 1.00 g, 32%.
1H NMR (CDCl3; 300 MHz; 293 K): δ 7.28 (m, 5 H, C6H5),
2.77 (m, 2 H, C6H5CH2CH2P), 1.73 (m, 2 H, C6H5CH2CH2P),
1.48 (q, J HH ) 7.8 Hz, 4 H, P(CH2CH3)2), 1.12 (m, 6 H,
P(CH2CH3)2). 31P{1H} NMR (CDCl3; 121 MHz; 293 K): δ -21.3
(s). 13C NMR (CDCl3; 75.5 MHz; 293 K): δ 143.06, 128.34,
128.03, 125.81, 32.28 (d, J CP ) 14.57 Hz), 28.20 (d, J CP ) 15.55
Hz), 18.64 (d, J CP ) 11.33 Hz), 9.50 (d, J CP ) 11.78 Hz).
Syn th esis of (p-cym en e)Ru (P Cy2CH2CH2C6H5)Cl2. The
synthesis was performed using an adaptation of a related
literature procedure.33 An aliquot of [(p-cymene)RuCl2]2 (3.14
g, 5.13 × 10-3 mol) was dissolved in 80 mL of benzene. To this
solution was added 2.5 equiv of crude C6H5CH2CH2PCy2
prepared as described above (note: the amount of C6H5CH2-
CH2PCy2 was estimated by integration using 1H NMR spec-
troscopy). The solvent was evaporated, and the resultant red
residue was extracted into CH2Cl2 and the extract filtered. The
solution was evaporated to dryness, and the resultant red solid
was washed with hexanes and diethyl ether and then dried
under vacuum. Yield: 4.63 g, 75%.1H NMR (CDCl3; 300 MHz;
293 K): δ 5.55 (s, 4 H, η6-CH3C6H4CH(CH3)2), 2.82 (m, 2 H,
C6H5CH2CH2P), 2.29 (m, 2 H, C6H5CH2CH2P), 2.10 (s, 3 H,
stability. Due to our inability to completely purify
complex 3, we were unable to characterize it fully, nor
were we able to evaluate its thermal stability. Analysis
of the thermal stabilities of complexes 1 and 2 revealed
that complex 1 is more stable than complex 2; further-
more, both complexes appear to be more thermally
stable than analogous nontethered systems described
in the literature. Preliminary studies of the use of
complexes 1 and 2 as catalyst precursors in the Ziegler-
Natta polymerization of ethylene revealed that neither
complex exhibited significant catalytic activity under the
limited polymerization conditions examined.
Exp er im en ta l Section
Ma ter ia ls a n d Meth od s. All solvents were dried by
passage through alumina and degassed by freeze-pump-thaw
methods prior to use. The compounds methyllithium and
2-(bromoethyl)benzene were purchased from Aldrich Chemical
Co. and used as received. Similarly, the compounds bis(µ-
chloro)bis[(p-cymene)chlororuthenium(II)], dicyclohexylchloro-
phosphine (ClPCy2), diphenylchlorophosphine (ClPPh2), and
diethylchlorophosphine (ClPEt2) were purchased from Strem
Chemical Co. and used as received. All deuterated solvents
were purchased from Cambridge Isotope Laboratories. Nuclear
magnetic resonance (NMR) spectra were recorded on a General
Electric QE-300 spectrometer operating at 300 MHz (for 1H),
75.5 MHz (for 13C), and 121 MHz (for 31P). Elemental analyses
were performed by National Chemical Consulting.
Syn th esis of C6H5CH2CH2P Cy2. To a cooled (0 °C) solution
of dry diethyl ether (60 mL) charged with dicyclohexylchloro-
phosphine (5.0 g, 2.1 × 10-2 mol) was added 1.1 equiv (9.0
mL of a 2.6 M solution; 2.4 × 10-2 mol) of C6H5CH2CH2MgBr
prepared by the reaction of magnesium and (2-bromoethyl)-
benzene in dry diethyl ether. The solution was warmed slowly
to room temperature and refluxed overnight under argon. The
excess Grignard reagent was destroyed by the addition of
degassed methanol, and the solution was concentrated under
vacuum. Due to apparent decomposition of the product during
attempted purification by column chromatography on silica gel,
the crude product was used in subsequent synthetic steps (vide
infra). 1H NMR (CDCl3; 300 MHz; 293 K): δ 7.26 (m, 5 H,
C6H5), 2.73 (m, 2 H, C6H5CH2CH2P), 1.2-2.2 (m, 24 H,
C6H5CH2CH2P, Cy2).
Syn th esis of C6H5CH2CH2P P h 2. An aliquot (25 mL, 6.8
× 10-2 mol) of a 2.7 M solution of C6H5CH2CH2MgBr in diethyl
ether was slowly added to a cooled (0 °C) solution of diphen-
ylchlorophosphine (10 g, 4.5 × 10-2 mol) in 100 mL of dry
diethyl ether. The solution was slowly warmed to room
temperature and refluxed overnight under argon. The excess
Grignard reagent was destroyed by the dropwise addition of
1 N HCl solution. The solution was then adjusted to basic pH
by the careful addition of a saturated solution of NaHCO3. The
organic phase was separated, and the aqueous phase was
extracted with diethyl ether (3 × 60 mL). The combined
organic phases were dried over MgSO4 and filtered. The
volatiles were removed under vacuum, and the product was
purified by column chromatography on silica gel using 40/1
hexanes/diethyl ether (Rf ) 0.46, 10/1 hexanes/diethyl ether).
Yield of white solid: 7.4 g, 56%.1H NMR (CDCl3; 300 MHz;
293 K): δ 7.15-7.69 (m, 15 H, Ar), 2.96 (m, 2 H, C6H5-
CH2CH2P), 2.59 (m, 2 H, C6H5CH2CH2P). 31P{1H} NMR
(CDCl3; 121 MHz; 293 K): δ -15.3 (s). 13C NMR (CDCl3; 75.5
MHz; 293 K): δ 142.68 (d, J CP ) 13.14 Hz, C6H5CH2CH2P),
138.72 (d, J CP ) 13.36 Hz, Ar), 132.91 (d, J CP ) 16.23 Hz, Ar),
132.70 (d, J CP ) 16.99 Hz, Ar), 128.56 (m, C6H5CH2CH2P, Ar),
126.08 (s, C6H5CH2CH2P), 32.25 (d, J CP ) 17.74 Hz), 30.30 (d,
J CP ) 13.14 Hz).
Ar-CH3), 1.40-2.03 (m, 23 H, Cy2, CH(CH3)2), 1.28 (d, J HH
)
6.9 Hz, 6 H, CH(CH3)2). 31P{1H} NMR (CD2Cl2; 121 MHz; 293
K): δ 25.5 (s). 13C NMR (CDCl3; 75.5 MHz; 293 K): δ 141.65
(Ar), 128,56 (m, Ar), 126.10 (Ar), 108.69 (η6-CH3C6H4CH-
(CH3)2), 94.11 (η6-CH3C6H4CH(CH3)2), 88.94 (η6-CH3C6H4CH-
(CH3)2), 83.66 (η6-CH3C6H4CH(CH3)2), 37.88 (d, J CP ) 20.5 Hz),
31.10 (d, J CP ) 5.1 Hz), 30.89, 29.45, 29.07, 27.74, 26.72, 22.55,
18.21. A satisfactory analysis could not be obtained. Anal.
Calcd for C30H45RuPCl2: C, 59.20; H, 7.40. Found: C, 58.43;
H, 7.28.
Syn th esis of (p-cym en e)Ru (P P h 2CH2CH2C6H5)Cl2. An
aliquot of [(p-cymene)RuCl2]2 (1.00 g, 1.63 × 10-3 mol) was
dissolved in 50 mL of benzene. To this solution was added 2.1
equiv of C6H5CH2CH2PPh2 (0.99 g, 3.4 × 10-3 mol). The
solution was heated at 45 °C for 3 h, and then the solvent was
removed by evaporation. The resultant red residue was
extracted into CH2Cl2, and the extract was filtered and
evaporated to dryness. The resultant red solid was washed
with hexanes and diethyl ether, and then dried under vacuum.
Yield: 1.85 g, 95%. 1H NMR (CDCl3; 300 MHz; 293 K): δ 7.94
(m, 4 H, PPh2), 7.53 (m, 6 H, PPh2), 7.13 (m, 3 H, C6H5), 6.93
(m, 2 H, C6H5), 5.26 (d, J HH ) 6.3 Hz, 2 H, η6-CH3C6H4CH-
(CH3)2, 5.09 (d, J HH ) 6.3 Hz, 2 H, η6-CH3C6H4CH(CH3)2, 2.85
(m, 2 H, C6H5CH2CH2P), 2.55 (m, 1 H, CH(CH3)2), 2.32 (m, 2
H, C6H5CH2CH2P), 1.90 (s, 3 H, Ar-CH3), 0.83 (d, J HH ) 6.9
Hz, 6 H, CH(CH3)2). 31P{1H} NMR (CDCl3; 121 MHz; 293 K):
δ 23.4 (s). 13C NMR (CDCl3; 75.5 MHz; 293 K): δ 141.65 (d,
J CP ) 12.16 Hz, Ar), 133.40 (d, J CP ) 8.23 Hz, Ph2), 133.28
(m, Ph2), 130.83 (Ph2), 128.35 (m, Ar), 126.02 (Ar), 108.39 (η6-
CH3C6H4CH(CH3)2), 93.94 (η6-CH3C6H4CH(CH3)2), 90.65 (η6-
CH3C6H4CH(CH3)2), 85.80 (η6-CH3C6H4CH(CH3)2), 30.15, 29.68,
25.19 (d, J CP ) 26.27 Hz), 21.48, 17.53. Anal. Calcd for C30H33
RuPCl2: C, 60.40; H, 5.54. Found: C, 60.65; H, 5.40.
-
Syn th esis of (p-cym en e)Ru (P Et2CH2CH2C6H5)Cl2. An
aliquot of [(p-cymene)RuCl2]2 (0.50 g, 8.2 × 10-4 mol) was
dissolved in 50 mL of benzene. To this solution was added 2.3
equiv of C6H5CH2CH2PEt2 (0.36 g, 1.9 × 10-3). The solution
was refluxed for 30 min, and the solvent was evaporated to
afford a red residue, which was extracted into CH2Cl2, filtered,
and evaporated to dryness. The resultant red solid was washed
with hexanes and diethyl ether and then dried under vacuum.
Yield: 0.78 g, 95%.1H NMR (CDCl3; 300 MHz; 293 K): δ 7.27
(m, 5 H, C6H5), 5.45 (m, 4 H, η6-CH3C6H4CH(CH3)2), 2.85 (m,
3 H, CH(CH3)2, C6H5CH2CH2P), 2.26 (m, 2 H, C6H5CH2CH2P),
2.17 (m, 4 H, P(CH2CH3)2), 2.11 (s, 3 H, Ar-CH3), 1.26 (d, J HH
) 6.9 Hz, 6 H, CH(CH3)2), 1.17 (m, 6 H, P(CH2CH3)2). 31P{1H}
Syn th esis of C6H5CH2CH2P Et2. This ligand was prepared
using a procedure analogous to that used to prepare C6H5CH2-

3064 Organometallics, Vol. 22, No. 15, 2003
Umezawa-Vizzini et al.
NMR (CDCl3; 121 MHz; 293 K): δ 21.2 (s). 13C NMR (CDCl3;
75.5 MHz; 293 K): δ 142.12 (d, J CP ) 12.30 Hz, Ar), 128.74
(Ar), 128.17 (Ar), 126.36 (Ar), 107.54 (η6-CH3C6H4CH(CH3)2),
94.59 (η6-CH3C6H4CH(CH3)2), 88.99 (η6-CH3C6H4CH(CH3)2),
Ta ble 3. Cr ysta l Da ta a n d Str u ctu r e Refin em en t
Deta ils for 1
compd
Me2RuPh(CH2)2P(C6H11)
2
empirical formula
C22H37PRu
84.86 (η6-CH3C6H4CH(CH3)2), 30.75, 29.93, 26.98 (d, J CP
)
fw
temp
433.56
243 K
24.23 Hz), 22.40, 18.38, 18.21 (d, J CP ) 25.82 Hz), 7.99 (d, J CP
) 6.88 Hz). Anal. Calcd for C22H33RuPCl2: C, 52.80; H, 6.60.
Found: C, 52.43; H, 6.47.
wavelength
cryst syst
space group
unit cell dimens
0.710 73 Å
triclinic
P1h
Syn th esis of (η6:η1-C6H5CH2CH2P Cy2)Ru Cl2. A sample
of 4.63 g (7.61 × 10-3 mol) of (p-cymene)Ru(PCy2CH2CH2C6H5)-
Cl2 was refluxed in 80 mL of degassed chlorobenzene for 6 h
under argon. Fine orange crystals, which formed during the
reaction, were isolated by filtration and washed with hexanes
and diethyl ether. The remaining solution was again refluxed,
and the crystals were collected. This process was repeated
three times until crystal formation was observed to cease. The
crystals were washed with hexanes and diethyl ether and dried
under vacuum. Yield: 3.40 g, 94%. 1H NMR (CDCl3; 300 MHz;
293 K): δ 6.22 (td, J HH ) 5.7 Hz, J HH ) 2.4 Hz, 1 H, η6-C6H5),
5.84 (t, J HH ) 5.7 Hz, 2 H, η6-C6H5), 5.01 (d, J HH ) 5.7 Hz, 2
H, η6-C6H5), 2.92 (m, 2 H, C6H5CH2CH2P), 2.63 (dt, J HH ) 7.5
Hz, J gem ) 18.6 Hz, 2 H, C6H5CH2CH2P), 2.27 (m, 2 H, Cy2),
1.28-1.83 (m, 20 H, Cy2). 31P{1H} NMR (CDCl3; 121 MHz; 293
K): δ 70.2 (s). 13C NMR (CDCl3; 75.5 MHz; 293 K): δ 112.00
(η6-C6H5), 97.66 (η6-C6H5), 90.88 (η6-C6H5), 75.25 (η6-C6H5),
34.67 (d, J CP ) 26.7 Hz), 34.15 (d, J CP ) 21.3 Hz), 32.07, 26.06-
27.53 (m). Anal. Calcd for C20H32RuPCl2: C, 50.53; H, 6.74.
Found: C, 50.66; H, 6.81.
Syn th esis of (η6:η1-C6H5CH2CH2P P h 2)Ru Cl2. A sample
of 2.2 g (3.7 × 10-3 mol) of (p-cymene)Ru(PPh2CH2CH2C6H5)-
Cl2 was refluxed in 50 mL of degassed chlorobenzene for 24 h
under argon. The solvent was removed under vacuum, and the
reddish brown residue was washed with hexane, diethyl ether,
and cold CH2Cl2. The compound was recrystallized from CH2-
Cl2/diethyl ether. Yield: 1.06 g, 62%. 1H NMR (CDCl3; 300
MHz; 293 K): δ 7.75 (m, 4 H, PPh2), 7.40 (m, 6 H, PPh2), 6.25
a
b
c
8.1930(1) Å
8.334(1) Å
15.904(3) Å
98.95(3)°
R
â
98.77(3)°
γ
102.76(3)°
1026.4(3) Å3
2
V
Z
density (calcd)
abs coeff
F(000)
1.403 g/mL
0.843 mm-1
456
cryst size
θ range for data collecn
limiting indices
0.3 × 0.3 × 0.2 mm
2.56-27.49°
-10 < h < 10, 0 < k < 8,
-20 < l < 20
3159
no. of rflns collected
no. of indep rflns
abs cor
max and min transmissn
refinement method
no. of data/restraints/params
goodness of fit on F2
final R indices (I > 4σ(I))
R indices (all data)
largest diff peak and hole
2831 (Rint ) 0.0181)
ψ scans
1.0000 and 0.6824
full-matrix least squares on F2
2822/6/239
1.041
R1 ) 0.0332, wR2 ) 0.0916
R1 ) 0.0365, wR2 ) 0.0952
0.605 and -0.554 e/Å3
diethyl ether as the eluant. The yellow fractions were collected
and subjected to slow evaporation of the diethyl ether to afford
yellow crystals of 1. Yield: 0.17 g, 37%.1H NMR (CD2Cl2; 300
MHz; 293 K): δ 5.13 (t, J HH ) 5.7 Hz, 2 H, η6-C6H5), 4.97 (d,
J HH ) 5.7 Hz, 2 H, η6-C6H5), 4.53 (t, J HH ) 5.7 Hz, 1 H, η6-
C6H5), 2.46 (m, 2 H, C6H5CH2CH2P), 2.10 (dt, J HH ) 7.5 Hz,
J gem ) 16.5 Hz, 2 H, C6H5CH2CH2P), 1.20-1.78 (m, 22 H, Cy2),
-0.02 (d, J HP ) 4.8 Hz, 6 H, Ru(CH3)2). 31P{1H} NMR (CD2-
Cl2; 121 MHz; 293 K): δ 64.4 (s). 13C NMR (CD2Cl2; 75.5 MHz;
(td, J HH ) 5.7 Hz, J HH ) 2.4 Hz, 1 H, η6-C6H5), 6.05 (t, J HH
)
5.7 Hz, 2 H, η6-C6H5), 4.50 (d, J HH ) 5.7 Hz, 2 H, η6-C6H5),
3.55 (m, 2 H, C6H5CH2CH2P), 2.64 (dt, J HH ) 7.2 Hz, J gem
)
20.4 Hz, 2 H, C6H5CH2CH2P). 31P{1H} NMR (CDCl3; 121 MHz;
293 K): δ 46.8 (s). 13C NMR (CDCl3; 75.5 MHz; 293 K): δ
133.55 (PPh2), 131.99 (PPh2), 131.29 (PPh2), 128.84 (PPh2),
112.39 (η6-C6H5), 98.65 (η6-C6H5), 88.52 (η6-C6H5), 79.81 (η6-
293 K): δ 110.65 (d, J CP ) 3.39 Hz, η6-C6H5), 96.53 (d, J CP
)
C6H5), 44.83 (d, J CP ) 33.3 Hz), 28.41. Anal. Calcd for C20H19
RuPCl2: C, 51.95; H, 4.11. Found: C, 52.26; H, 3.88.
-
3.02 Hz, η6-C6H5), 82.21 (η6-C6H5), 78.54 (d, J CP ) 13.8 Hz,
η6-C6H5), 39.12 (d, J CP ) 25.3 Hz), 34.00 (d, J CP ) 17.7 Hz),
31.36 (d, J CP ) 6.6 Hz), 28.40, 28.07 (d, J CP ) 11.48 Hz), 27.78
(d, J CP ) 9.06 Hz), 27.53, 27.13, -12.67 (d, J CP ) 15.7 Hz). A
satisfactory analysis could not be obtained. Anal. Calcd for
Syn th esis of (η6:η1-C6H5CH2CH2P Et2)Ru Cl2. A sample of
0.5 g (1 × 10-3 mol) of (p-cymene)Ru(PEt2CH2CH2C6H5)Cl2 was
refluxed in 50 mL of degassed chlorobenzene for 16 h under
argon. The solvent was removed under vacuum, and the
reddish brown residue was washed with hexane and diethyl
ether. The compound was recrystallized from CH2Cl2/diethyl
ether. Yield: 0.29 g, 80%.1H NMR (CDCl3; 300 MHz; 293 K):
δ 6.23 (td, J HH ) 5.7 Hz, J HH ) 2.4 Hz, 1 H, η6-C6H5), 5.89 (t,
J HH ) 5.7 Hz, 2 H, η6-C6H5), 4.90 (d, J HH ) 5.7 Hz, 2 H, η6-
C6H5), 2.98 (m, 2 H, C6H5CH2CH2P), 2.68 (dt, J HH ) 7.2 Hz,
J gem ) 20.4 Hz, 2 H, C6H5CH2CH2P), 2.05 (m, 4 H, P(CH2-
CH3)2), 1.19 (m, 6 H, P(CH2CH3)2). 31P{1H} NMR (CD2Cl2; 121
MHz; 293 K): δ 63.7 (s). 13C NMR (CDCl3; 75.5 MHz; 293 K):
δ 112.32 (η6-C6H5), 98.86 (η6-C6H5), 88.58 (η6-C6H5), 75.32 (η6-
C6H5), 38.69 (d, J CP ) 29.46 Hz), 30.49, 18.17 (d, J CP ) 26.50
Hz), 7.99. Anal. Calcd for C12H19RuPCl2: C, 39.34; H, 5.19.
Found: C, 39.20; H, 5.04.
C
22H38RuP: C, 60.83; H, 8.75. Found: C, 61.31; H, 8.48.
Syn th esis of (η6:η1-C6H5CH2CH2P P h 2)Ru (CH3)2 (2). The
synthesis of compound 2 was performed using a procedure
analogous to that used to prepare compound 1. Yellow crystals
of 2 were obtained by the slow evaporation of CH2Cl2. Yield:
48%.1H NMR (CD2Cl2; 300 MHz; 293 K): δ 7.36 (m, 10 H,
PPh2), 5.42 (t, J HH ) 5.7 Hz, 2 H, η6-C6H5), 5.10 (d, J HH ) 5.7
Hz, 2 H, η6-C6H5), 4.87 (t, J HH ) 5.7 Hz, 1 H, η6-C6H5), 2.96
(m, 2 H, C6H5CH2CH2P), 2.11 (dt, J HH ) 7.2 Hz, J gem ) 21.9
Hz, 2 H, C6H5CH2CH2P), -0.19 (d, J HP ) 6.0 Hz, 6 H, Ru-
(CH3)2). 31P{1H} NMR (CD2Cl2; 121 MHz; 293 K): δ 63.7 (s).
13C NMR (CD2Cl2; 75.5 MHz; 293 K): δ 135.24 (d, J CP ) 34.88
Hz, Ph2), 133.36 (d, J CP ) 9.66 Hz, Ph2), 129.67, 128.38 (d,
J CP ) 9.21 Hz, Ph2), 108.46 (η6-C6H5), 98.97 (η6-C6H5), 84.87
(η6-C6H5), 76.68 (d, J CP ) 15.2 Hz, (η6-C6H5), 47.48 (d, J CP
30.9 Hz), 28.64 (d, J CP ) 7.5 Hz), -10.82 (d, J CP ) 16 Hz).
Anal. Calcd for C22H25RuP: C, 62.71; H, 5.94. Found: C, 62.87;
H, 5.98.
Syn th esis of (η6:η1-C6H5CH2CH2P Et2)Ru (CH3)2 (3). The
corresponding dichloride, (η6: η1-C6H5CH2CH2PEt2)RuCl2 (0.123
g, 3.34 × 10-4 mol), was suspended in 20 mL of diethyl ether.
To the above solution was added 5 equiv of methyllithium (1.69
× 10-3 mol) at -78 °C. The solution was gradually warmed to
)
Syn th esis of (η6:η1-C6H5CH2CH2P Cy2)Ru (CH3)2 (1). The
corresponding dichloride, (η6: η1-C6H5CH2CH2PCy2)RuCl2 (0.50
g, 1.1 × 10-4 mol), was suspended in 20 mL of dry diethyl
ether. To the above solution was added 6.2 equiv of methyl-
lithium (6.8 × 10-3 mol) at -78 °C. The solution was gradually
warmed to room temperature and stirred for 1 h. The solvent
was evaporated, and the residue was extracted with benzene.
The brown solid obtained after evaporation of the benzene was
purified by column chromatography on particulate Al2O3 using

(η6:η1-C6H5CH2CH2PR2)Ru(CH3)2
Organometallics, Vol. 22, No. 15, 2003 3065
Ta ble 4. Cr ysta l Da ta a n d Str u ctu r e Refin em en t
for 2
collection parameters for compounds 1 and 2 are summarized
in Tables 3 and 4, respectively. The data were corrected for
Lorentz and polarization effects and for absorption correction
using ψ scans. Crystal and instrument stability were checked
by measuring 3 standard reflections every 150 observations.
Structures were solved using SHELXS-9744 on a PC. Weighted
R factors (Rw) and all goodness of fit values (S) were based on
F2; conventional R factors (R) were based on F. The H atom
positions were refined using a riding model.
compd
empirical formula
fw
Me2RuPh(CH2)2P(C6H5)2
C22H25PRu
421.46
temp
213 K
wavelength
cryst syst
space group
0.710 73 Å
monoclinic
P21/n
unit cell dimens
Tr ia l P olym er iza tion s of Eth ylen e Usin g MAO-Acti-
va ted 1 a n d 2.45 These experiments were performed in a
Fisher-Porter bottle equipped with a pressure release valve,
a sample injection inlet, an ethylene and argon inlet, and a
pressure gauge. In a typical polymerization trial, a mixture
of MAO (1000-3000 equiv based on Ru) and toluene (30 mL)
were placed in the Fisher-Porter bottle, which was then
pressurized with ethylene at 40 psi for 5 min. The pressure of
ethylene was slowly reduced to 25 psi, and a solution contain-
ing the ruthenium complexes (10 or 20 µmol) was injected by
syringe under a flow of ethylene. The reactor was pressurized
with ethylene (8.5 atm), and the reaction mixture was stirred
for 1-2 h at temperatures adjusted to either 25 or 50 °C over
several independent runs. The reaction mixture was then
slowly poured into a methanolic solution containing 5% HCl
to precipitate any polyethylene formed in the reaction.
a
b
c
11.210(2) Å
14.089(3) Å
12.143(2) Å
90°
R
â
98.02(3)°
γ
90°
V
Z
1899.1(6) Å3
4
density (calcd)
abd coeff
F(000)
cryst size
θ range for data collecn
limiting indices
1.474 g/mL
0.910 mm-1
864
0.40 × 0.35 × 0.30 mm
2.23-27.50°
0 < h < 12, 0 < k < 18,
-15 < l < 15
3345
3130 (Rint ) 0.0448)
ψ scans
no. of rflns collected
no. of indep rflns
abs cor
max and min transmissn
refinement method
no. of data/restraints/params
goodness of fit on F2
final R indices (I > 2σ(I))
R indices (all data)
largest diff peak and hole
1.0000 and 0.9076
full-matrix least squares on F2
3129/0/219
Ack n ow led gm en t. The Robert A. Welch Founda-
tion (Grants C-0976 and E-1320) and the National
Science Foundation (Grant CHE-9983352 and CAREER
Award to T.R.L., Grant CHE-9625003) provided gener-
ous support for this research. We thank Dr. J ames Korp
for technical assistance with the X-ray crystallographic
analyses.
1.089
R1 ) 0.0328, wR2 ) 0.0949
R1 ) 0.0432, wR2 ) 0.0998
0.834 and -0.430 e/Å3
room temperature and stirred for 1 h. The solvent was
evaporated, and the residue was extracted with benzene. The
brown solid obtained after evaporation of benzene was sub-
jected to column chromatography on particulate Al2O3 using
diethyl ether as the eluant. A yellow solution was collected,
which turned brown during evaporation of the diethyl ether.
The apparent decomposition precluded the isolation of the pure
Su p p or tin g In for m a tion Ava ila ble: Tables giving X-ray
crystallographic data for complexes 1 and 2 and figures giving
1H NMR spectra for complexes 1-3. This material is available
free of charge via the Internet at http://pubs.acs.org.
1
samples of 3. H NMR (C6D6; 300 MHz; 293 K): δ 5.04 (t, J HH
OM0300070
) 5.7 Hz, 2 H, η6-C6H5), 4.65 (t, J HH ) 5.7 Hz, 1 H, η6-C6H5),
4.53 (d, J HH ) 5.7 Hz, 2 H, η6-C6H5), 1.87 (m, 2 H, C6H5-
CH2CH2P), 1.60 (dt, J HH ) 7.5 Hz, J gem ) 18.0 Hz, 2 H,
C6H5CH2CH2P), 1.34 (m, 4 H, P(CH2CH3)2), 0.81 (m, 6 H,
P(CH2CH3)2), 0.50 (d, J HP ) 5.7 Hz, 6 H, Ru(CH3)2).
(43) Molecular Structure Corporation Single-Crystal Structure Analy-
sis Software (1995b); MSC, 3200 Research Forest Drive, The Wood-
lands, TX 77381.
(44) Sheldrick, G. M. Acta Crystallogr. 1990, A46, 467.
(45) The polymerization apparatus and reagents were examined for
possible contamination through control experiments using Cp2ZrHCl
as the catalyst precursor. In these experiments, ample amounts of
polyethylene were produced.
X-r a y Cr ysta l Str u ctu r e Deter m in a tion s. The data were
collected using the TEXSAN43 automatic data collection series
on a Rigaku AFC5S diffractometer. The crystallographic data