Coordination of a Ru(II)-complex to a tetrafunctional P-ligand: A model for Ru-P carbosilane dendrimers

Article abstract of DOI:10.1016/S0022-328X(00)00186-8

Organophosphine-functionalised carbosilane (CS) dendrimers (5, 6) can be synthesised in high yield. Furthermore, new kinds of metallodendrimers (7, 8) are obtained by coordination of a Ru(II) complex, containing the tridentate triamine ligand: 2,6-bis[(dimethylamino)methyl]pyridine, to these P-functionalised CS-dendrimers.

Full text of DOI:10.1016/S0022-328X(00)00186-8

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Journal of Organometallic Chemistry 603 (2000) 244–248
Short Communication
Coordination of a Ru(II)-complex to a tetrafunctional P-ligand: a
model for RuꢀP carbosilane dendrimers
Herlinde I. Beerens a,*, Peter Wijkens b, Johann T.B.H. Jastrzebski b,
Francis Verpoort a, Ludo Verdonck a, Gerard van Koten b
a Department of Inorganic and Physical Chemistry, Organometallics and Catalysis Di6ision, Uni6ersity of Ghent, Krijgslaan 281 (S-3),
B-9000 Gent, Belgium
b Department of Metal-Mediated Synthesis, Debye Institute, Utrecht Uni6ersity, Padualaan 8, 3584 CH Utrecht, The Netherlands
Received 24 January 2000; received in revised form 11 March 2000
Abstract
Organophosphine-functionalised carbosilane (CS) dendrimers (5, 6) can be synthesised in high yield. Furthermore, new kinds
of metallodendrimers (7, 8) are obtained by coordination of a Ru(II) complex, containing the tridentate triamine ligand:
2,6-bis[(dimethylamino)methyl]pyridine, to these P-functionalised CS-dendrimers. © 2000 Elsevier Science S.A. All rights re-
served.
Keywords: Carbosilane dendrimers; Phosphines; Ruthenium(II)-complexes; Metalations
1. Introduction
We observed that during the catalysis the PPh3ꢀRu
bond is inert. Furthermore, the synthesis of 1 is easy
Recently, new dendritic structures with a precise
number and location of chemical functionalities on the
surface have been reported [1]. Dendritic compounds
with phosphine or amine ligands have been used for the
synthesis of supported metal catalysts by coordinating a
suitable metal salt to the surface supported ligand [2].
However, an obvious problem of these supported metal
catalysts is metal leaching as a result of reversibility of
the metal–ligand (surface) coordination. Even in the
case of bi- or tridentate ligand–metal binding, metal
leaching can occur.
In a previous study we found that mononuclear
Ru(II) complexes, [Ru(NN%N)(PPh3)Cl2] (1, NN%N=
2,6-bis[(dimethylamino)methyl]pyridine), are interesting
catalysts for the cycloalkylation of aromatic amines
with alcohols to give piperazines and piperidines [3].
Scheme 1. Synthesis of phosphine-functionalised CS-dendrimers.
Reagents and conditions: (i) 4.4 eq. 1,4-Br2C6H4, 4.2 eq. n-BuLi,
Et2O, RT; (ii) 4.2 eq. n-BuLi, Et2O, RT; (iii) 4.4 eq. CIPR2
(5, R=Ph; 6, R=Cy), Et2O, RT.
* Corresponding author. Tel.: +32-92-644440; fax: +32-92-
644983.
E-mail address: herlinde.beerens@rug.ac.be (H.I. Beerens)
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(00)00186-8

H.I. Beerens et al. / Journal of Organometallic Chemistry 603 (2000) 244–248
245
Scheme 2. Coordination of the Ru-complexes on the phosphine-functionalised CS-periphery
and comprises a 2:1 reaction of the free phosphine
ligand with the N2-bridged binuclear complex
[{RuCl2(h3-NN%N)}2(m-N2)] (2) [4].
The inert PPh3ꢀRu binding in 1 as well as its
straightforward synthesis, prompted the present study
which is directed to the synthesis of carbosilane (CS)
dendrimers which carry a well-defined number of tri-
arylphosphine or dicyclohexylphosphine ligands, and
also the study of the binding of a RuCl2(NN%N)-unit to
these phosphine ligands.
For the coordination of the Ru-complexes to the
triphenylphosphine CS-dendrimers, the organophos-
phine dendrimer, 5, is stirred with an equimolar quan-
tity of the RuN2Ru-complex [6] for 4 h in CH2Cl2 at r.t.
The two sharp 31P{1H}-NMR resonances at −4.9
and 38.2 ppm, for the uncoordinated phosphine and the
coordinated phosphine, respectively, indicated that an
incomplete metal loading had occurred; only 70% of
the surface phosphine ligands were occupied. In further
experiments the reaction mixture was stirred for longer
periods, but even after 25 h only 80% of the
RuCl2(NN%N)-units were linked to the CS dendrimers.
Upon reacting 5 with an excess of the Ru-complex,
within 15 min full metallation was obtained (Scheme 2).
The excess of the Ru-complex could be removed com-
pletely by washing crude 7 with a mixture of Et2O–pen-
tane (1:5 mol ratio).
2. Results and discussion
The organophosphine-functionalised CS dendrimers,
which were prepared via the route shown in Scheme 1,
starts from the reaction of the CS dendrimer with the
p-lithiated bromobenzene in Et2O. The organophos-
phine dendrimers, 5 and 6 were obtained in 97 and 93%
yield, respectively.
In spite of the better donating properties of the
PCy2-ligands, the 1:2 molar reaction of the CSꢀPCy2
ligand with the RuN2Ru-complex lead likewise to in-
complete metal loading. This is evident by the observa-
tion of two 31P{1H}-NMR resonances at 2.2 ppm (free
phosphine) and 12.5 ppm (coordinated phosphine).
Again using an excess of the Ru-complex afforded the
fully metalled CSꢀPCy2ꢀRu complex 8. However at-
tempts to remove the excess of the Ru-complex by
washing with a mixture of Et2O–pentane (1:5 mol
ratio) failed; still unreacted Ru-complex was present in
the solids obtained.
The structures of the dendritic phosphine ligands
1
were confirmed by H, 13C{1H}, 31P{1H}-NMR spec-
troscopy and mass spectrometric analysis (MALDI-
TOF) (see Section 4). In the 31P-NMR, the resonance
signal shifted from −4.7 ppm for the free PPh3 to
−4.9 ppm for compound 5. This may be caused by a
small effect of the p-Si attachment of Ph3P on the
chemical shift in 31P-NMR. A similar effect of a p-Si
aryl substituent on the chemical shift in 31P-NMR was
found by the combination of a p-Si-fluorotail to PPh3
[5].
Both 31P{1H}-NMR spectra of 7 and 8 show only
one sharp signal at 38.2 ppm (CSꢀPPh2Ru, 7) and 12.5
ppm (CSꢀPCy2Ru, 8). No peaks for any residual un-

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H.I. Beerens et al. / Journal of Organometallic Chemistry 603 (2000) 244–248
bounded dendritic phosphine groups were observed,
suggesting high efficiency of metal loading on these
organophosphine dendrimers. The spectrum of 7 resem-
bled that of the corresponding PPh3 complex
[Ru(NN%N)PPh3Cl2], which showed a signal at 37 ppm
[4]. The coordination chemical shifts of 7 and 8 are 43.1
and 10.3 ppm, respectively. Both are positive as ex-
pected since on coordination the phosphorus atom is
deshielded.
(75 MHz) and 31P (81 and 121 MHz)-NMR were
recorded on a Varian inova 200–300 MHz spectrome-
1
ter. For H and 13C-NMR, TMS was used as external
standard and C6D6 or CD2Cl2 were used as solvents.
For 31P-NMR, 85% H3PO4 was used as standard and
C6D6 or CD2Cl2 were used as solvents. MALDI-TOF:
The MALDI-TOF mass spectra were obtained using a
Voyager-DE BioSpectrometry Workstation (PerSeptive
Biosystems Inc., Framingham, MA) mass spectrometer
equipped with a nitrogen laser emitting at 337 nm. The
instrument was operated in the linear mode at an
accelerating voltage in the range of 23 000–25 000 V.
Detection was done by means of a linear detector and
a digitizing oscilloscope operating at 500 MHz. Sample
solutions with an approximate concentration of 30 mg
ml−1 in CH2Cl2 were prepared. The matrix was 9-ni-
troantracene. In the case of the unloaded dendrimer the
silver salt of trifluoroacetic acid was added to the
matrix to improve the ionization. The elemental analy-
sis was performed by Dornis and Kolbe, Mikroanalytis-
ches Laboratorium, Mu¨lheim a.d. Ruhr, Germany.
Comparison of the 1H- and 13C{1H}-NMR spectra of
2 and 7 was also instructive. In particular the reso-
nances of the CH2-groups and the NMe2 groups of 2 at
4.20 and 2.80 ppm, respectively, were shifted to higher
field in 7 (3.98 ppm and 2.06 ppm), which was a clear
indication of the coordination of the Ru-complex to the
periphery of the dendrimer. The same chemical shift
was found for the CSꢀPCy2ꢀRu complex, 8. Addition-
ally, the peak broadening for these resonances evi-
denced the ligation of the Ru-complexes to the
phosphines.
1
An unambigous assignment of all the H-NMR sig-
nals of compound 8 was not possible.
The pattern of the CH2-protons of the dendrimer is
completely mixed with the signals of the
cyclohexylprotons.
The MALDI-TOF spectrum of 7 doesn’t provide
additional information about the triphenylphosphine
CS-dendrimer with Ru-complexes on the periphery.
The mass spectrum showed characteristic fragmentation
of which only a few peaks could be determinated.
4.1. Synthesis of G0–SiMe2C6H4Br (3)
To a solution of 1,4-dibromobenzene (10.5 ml, 44.40
mmol) in Et2O (50 ml) was added nBuLi (26.40 ml, 1.6
M solution in hexane) at −78°C. The resulting reac-
tion mixture was stirred for 2 h at r.t. Then a solution
of G0–SiMe2Cl (5.7 g, 10.0 mmol) in Et2O (10 ml) was
added dropwise to the lithiation reaction mixture at
0°C. The reaction mixture was allowed to warm up to
r.t. and stirred overnight. Water was slowly added and
the organic layer was washed three times with water,
dried over MgSO4, filtered and concentrated in vacuo.
The residue was purified by Kugelrohr distillation (1.5
h at 120°C, 0.1 mmHg) and column chromatography
(silica/hexane; hexane:ether=3:1). Yield: 7.9 g (75%) of
an off-white syrup.
3. Conclusions
In conclusion we have demonstrated in this paper the
synthesis of organo-phosphine-functionalised CS den-
drimers. New kinds of metallodendrimers are synthe-
sized by specific complexation of the phosphine groups
on the outer surface of the carbosilane dendrimers with
the bridged RuN2Ru-complex. The dendrimer surface
can be easily and effectively occupied with the metal
centers. This is to the best of our knowledge the first
example of a Ru-complex linked to phosphine-func-
tionalised carbosilane dendrimers. The aim of further
investigations is the application of these Ru phosphine-
functionalised CS dendrimers as catalyst precursors.
1H-NMR (300 MHz, acetone-d6): l=7.53 (d, 8H,
J=8.2 Hz, ArH), 7.45(d, 8H, J=8.2 Hz, ArH), 1.35–
1.39 (m, 8H, ꢀCꢀCH2ꢀCꢀ), 0.82 (t, 8H, J=8.1 Hz,
ꢀCH2ꢀSiꢀAr), 0.58 (t, 8H, J=8.1Hz, ꢀCH2ꢀSiꢀCH2ꢀ),
0.28 (s, 24H, SiꢀMe).13C{1H}-NMR (75 MHz, acetone-
d6): l=138.8, 135.7, 131.1, 123.5 (4×ArꢀC), 20.5
(CH2SiAr), 18.7 (ꢀCꢀCH2ꢀC), 17.4 (CH2ꢀSiꢀCH2), −
3.1 (SiꢀMe). B MS (MALDI-TOF): m/z=1159.74
[M+Ag]+ (calc. 1160.95). Anal. Calc. for C44H64Br4Si5
(Mw=1053.08): C, 50.18; H, 6.13; Br, 30.35; Si, 13.34.
Found: C, 50.32; H, 6.25; Br, 30.45; Si, 13.31.
4. Experimental
All manipulations were performed under a dry and
deoxygenated N2 atmosphere using standard Schlenck
techniques. All solvents were carefully dried and dis-
tilled prior to use. The bridged Ru-complex, 2 and the
dendritic silicon chloride G0–SiMe2Cl [8] were synthe-
4.2. Synthesis of G0–SiMe2C6H4P(C6H5)2 (5)
To a solution of G0ꢀSiMe2C6H4Br (1.64 g, 1.56
mmol) in Et2O (25 ml) was added nBuLi (4.2 ml, 1.6 M
solution in hexane) at room −78°C. The resultant
reaction mixture was allowed to warm up to r.t. and
1
sized according to literature [6,7]. H (300 MHz), 13C

H.I. Beerens et al. / Journal of Organometallic Chemistry 603 (2000) 244–248
247
whirl-mixed for 1 h, during which a sticky material was
formed along the glass walls. After addition of
chlorodiphenylphosphine (1.2 ml, 6.9 mmol), the mix-
ture was whirl-mixed until the sticky material was
dissolved and the product, which was precipitated as a
white solid, was formed. The reaction mixture was
stirred overnight and the precipitate was collected by
centrifugation. After evaporation of the solvents, the
last volatiles were removed by Kugelrohr distillation (2
h at 130°C, 0.05 mmHg) to afford 5 (2.23 g, 97%) as an
off-white sticky material.
(1.64 ml, 6.9 mmol), the mixture was whirl-mixed until
the sticky material was dissolved and a white precipi-
tate was formed. The reaction mixture was stirred
overnight, whereupon the precipitate was collected by
centrifugation. After evaporation of the solvents the
last volatiles were removed by Kugelrohr distillation
(1.5 h at 110°C, 0.05 mmHg). Yield: 2.21 g (93%).
1H-NMR (300 MHz, C6D6): l=7.62–7.51 (m, 16H,
ArH), 2.10–1.80, 1.80–1.40 (all m, 56H, Cy), 1.25–1
(m, 40H, SiCH2CH2+Cy), 0.85 (t, 8H, J=8.1 Hz,
CH2SiAr), 0.59 (t, 8H, J=8.1 Hz CH2ꢀSiꢀCH2), 0.24
(s, 24H, SiMe). 13C{1H}-NMR (75 MHz, C6D6) l=
140.6 (s, CipsoꢀSi, C5), 136.5 (d, J=20.6 Hz, CipsoꢀP,
C8), 134.6 (d, J=18.8 Hz, ArCo vs. P, C7), 133.4 (d,
J=6.7 Hz, ArCm vs P, C6), 33 and 30.5 (d, J=13.4 Hz
and J=17 Hz, CyC, C10), 29.3 and 27.4 (d, J=7.9 Hz
and J=7.3 Hz, CyC, C11), 27.6 (d, J=12 Hz, CyC,
C9), 26.8 (s, CyC, C12), 20.9 (CH2SiAr, C3), 19.1
(ꢀCꢀCH2ꢀC, C2), 17.8 (CH2ꢀSiꢀCH2, C1), −2,7 (SiMe,
C4). 31P{1H}-NMR (81 MHz, C6D6) l 2.2. MS
(MALDI-TOF): m/z=1630.60 [6+Ag]+ (calc.
1630.44).
1H-NMR (300 MHz, C6D6): l=7.48–7.15 (m, 24H,
C6H5 and C6H4, Ho vs. P), 7.10–6.85 (m, 32H, ArHm,p
)
1.47–1.43 (m, 8H, ꢀCꢀCH2ꢀC), 0.80 (t, 8H, J=8.1 Hz,
CH2SiAr), 0.62 (t, 8H, J=8.1 Hz, ꢀCH2ꢀSiꢀCH2ꢀ),
0.21 (s, 24H, SiMe).13C{1H}-NMR (75 MHz, C6D6):
l=140.2 (s, ArCꢀSi), 138.8 (d, J=12.1 Hz, CipsoꢀP of
ꢀC6H4ꢀ), 137.9 (d, J=12.1 Hz, Cipso of C6H5), 134.2 (d,
J=19.4 Hz, C6H5ꢀC ortho vs. CipsoꢀP), 134. (d, J=6.7
Hz, C6H4ꢀC, meta vs. CipsoꢀP), 133.5 (d, J=18.8 Hz,
C6H4ꢀC, ortho vs. CipsoꢀP), 128.9 (s, C6H5ꢀC para vs.
CipsoꢀP), 128.8 (d, J=6.7 Hz, C6H5ꢀC meta vs.
CipsoꢀP), 20.7 (CH2SiAr), 19.1 (ꢀCH2ꢀCH2ꢀCH2), 17.8
(CH2ꢀSiꢀCH2), −2.8 (SiMe). 31P{1H}-NMR (81 MHz,
C6D6) l= −4.9 (s). MS (MALDI-TOF): m/z=
1583.69 [5+Ag]+ (calc. 1582.06).
4.4. Synthesis of G0–SiMe2ꢀPPh2ꢀ[Ru] [9] (7)
To a solution of the bridged Ru-complex, 2 (0.08 g,
0.17 mmol) in CH2Cl2 (8 ml) was added a solution of 5
(0.062 g, 0.042 mmol) in CH2Cl2 (15 ml). The resulting
reaction mixture was stirred for 15 min at r.t. Then
Et2O–pentane (1:5) was added to precipitate the crude
product. After washing with the mixture of Et2O–pen-
tane (1:5) a brown viscous slurry of CSꢀPPh2ꢀ[Ru] was
obtained in 86% (0.12 g). (based on starting 1,4-
dibromobenzene).
4.3. Synthesis of G0–SiMe2C6H4P(C6H11)2 [9](6)
The biscyclohexyl compound was synthesized as de-
scribed for 5: To a solution of G0–SiMe2C6H4Br (1.64
g, 1.56 mmol) in Et2O (25 ml) was added nBuLi (4.2
ml, 1.6 M solution in hexane) at −78°C. The reaction
mixture was allowed to warm up to r.t., during which
time a sticky material was formed along the glass walls.
The resulting reaction mixture was whirl-mixed during
1 h. After addition of chlorodicyclohexylphosphine
1H-NMR (300 MHz, CD2Cl2): l=8.06–8.14 (m,
24H, C6H5 and C6H4, Ho vs. P, H6 and H7), 7.73 (t, 4H,
J=7.5 Hz, ArHp, pyr, H13), 7.43 (dd, 8H, JP H=1.8
ꢀ
Hz, JH H=6.3 Hz, C6H4, Hm vs. P, H5), 7.37 (d, 8H,
ꢀ
Scheme 3.

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H.I. Beerens et al. / Journal of Organometallic Chemistry 603 (2000) 244–248
J=7.8 Hz, ArHm, pyr, H12), 7.26–7.35 (m, 24H, C6H5,
Hm,p vs. P, H8 and H9), 3.98 (s, 16H, CH2NMe2, H11),
2.06 (s, 48H, N(CH3)2, H10), 1.40–1.26 (m, 8H,
CꢀCH2ꢀC, H2), 0.76 (t, 8H, J=8.1 Hz, CH2ꢀSiꢀAr,
H3), 0.52 (t, 8H, J=8.1 Hz, CH2ꢀSiꢀCH2, H1), 0.19 (s,
24H, SiMe, H4). 13C{1H}-NMR (75 MHz, CD2Cl2):
l=162.1 (Co to N py, C15), 140.4 (d, J=1.2 Hz,
ArꢀCꢀSi, C5), 140.2 (d, J=30.9 Hz, CipsoꢀP of C6H4,
C8), 139.3 (d, J=31.6 Hz, CipsoꢀP of C6H5, C9), 135.4
(Cp, py, C17), 134.7 (d, J=9.2 Hz, C6H5ꢀC ortho vs.
CipsoꢀP, C10), 133.7 (d, J=9.1 Hz, C6H4ꢀC ortho vs.
CipsoꢀP, C7), 132.9 (d, J=7.9 Hz,C6H4ꢀC meta vs.
CipsoꢀP, C6), 128.5 (ArCp, PPh2, C12), 127.7 (d, J=8.5
Hz, C6H5ꢀC meta vs. CipsoꢀP, C11), 119.7 (Cm, py, C16),
74 (CH2N(CH3)2, C14), 55.7 (N(CH3)2, C13), 20.8
(CꢀCH2ꢀC, C2), 19 (CH2ꢀSiꢀAr, C3), 17.7
(CH2ꢀSiꢀCH2, C1), −2.8 (SiMe, C4). 31P{1H}-NMR
(121 MHz, CD2Cl2): l=38.2. MS (MALDI-TOF): m/
z=331.14 [Ru(NN%N)Cl]+ (calc. 330.4), 363.00
[Ru(NN%N)Cl2] (calc. 365.3), 1490.00 [CSꢀPPh2-ox1]
(calc. 1490.19), 1511.44 [CSꢀPPh2-ox2] (calc. 1506.19),
398.83 [Ru(NN%N)Cl3]− (calc. 401.8).
(Belgium) (F.W.O.-Vlaanderen). H.I.B. is indebted to
I.W.T. for a positon as research assistant.
References
[1] (a) J.W.J. Knapen, A.W. van der Made, J.C. de Wilde,
P.W.N.M. van Leeuwen, P. Wijkens, D.M. Grove, G. van
Koten, Nature 372 (1994) 659. (b) M.A. Hearshaw, J.R. Moss,
J. Chem. Soc. Chem. Commun. 1 (1999) 1. (c) C. Gorman, Adv.
Mater. 10 (1998) 295. (d) E. Constable, P. Harverson, Inorg.
Chim. Acta 252 (1996) 9. (e) C. Galliot, D. Pre´vote´, A.M.
Caminade, J.P. Majoral, J. Am. Chem. Soc. 117 (1995) 5470. (f)
G. L’abbe´, B. Forier, W. Dehaen, J. Chem. Soc. Chem. Com-
mun. 18 (1996) 2143. (g) J.W. Leon, M. Kawa, M.J. Fre´chet, J.
Am. Chem. Soc. 118 (1996) 8847. (h) M. Slany, A.M. Caminade,
J.P. Majoral, Tetrahedron Lett. 37 (1996) 50 9053. (i) H. Frey,
K. Lorenz, R. Mu¨lhaupt, Macromol. Symp. 102 (1996) 19. (j)
M. Jayaraman, M.J. Fre´chet, J. Am. Chem. Soc. 120 (1998)
12996. (k) N.J.Hovestad, E.B. Eggeling, J.H. Heidbu¨chel,
J.T.B.H. Jastrzebski, U. Kragl, W. Keim, D. Vo¨gt, G. van
Koten, Angew. Chem. Int. Ed. 30 (1999) 1655. (l) M. Petrucci-
Samija, V. Guillemette, M. Dasgupta, A.K. Kakkar, J. Am.
Chem. Soc. 121 (1999) 1968.
[2] (a) A. Miedaner, C.J. Curtis, R.M. Barkley, D.L. Dubois, Inorg.
Chem. 33 (1994) 5482. (b) M. Bardaji, M. Kustos, A. Caminade,
J.P. Majoral, Organometallics 16 (1997) 403. (c) M.T. Reetz, G.
Lohmer, R. Schwickardi, Angew. Chem. Int. Ed. 36 (1997) 1526.
(d) M. Slany, M. Bardaji, A.M. Caminade, B. Chaudret, J.P.
Majoral, Inorg. Chem. 36 (1997) 1939. (e) M. Bardaji, A.M.
Caminade, B. Chaudret, J.P. Majoral, Organometallics 16 (1997)
3489. (f) C. Ko¨llner, B. Pugin, A. Togni, J. Am. Chem. Soc. 120
(1998) 10274. (g) C. Vale´rio, E. Alonso, J. Ruiz, J.C.D. Blais-As-
truc, Angew. Chem. Int. Ed. Engl. 38 (1999) 1747. (h) J. Iss-
berner, M. Bo¨hme, S. Grimme, M. Nieger, W. Paulus, F.
Vo¨gtle, Tetrahedron: Asymm. 7 (1996) 2223.
4.5. Synthesis of G0ꢀSiMe2ꢀPCy2ꢀ[Ru] (8)
To a solution of the bridged Ru-complex, 2 (0.08 g,
0.17 mmol), in CH2Cl2 (8 ml) was added a solution of
6 (0.064 g, 0.042 mmol) in CH2Cl2 (15 ml). The result-
ing reaction mixture was stirred for 15 min at r.t.,
whereupon the mixture was concentrated to a third.
Then Et2O–pentane (1:5) was added to precipitate the
crude product. After washing with the mixture of
[3] R.A.T.M. Abbenhuis, J. Boersma, G. van Koten, J. Org. Chem.
63 (1998) 4282.
[4] I. del R´ıo, R.A. Gossage, M. Lutz, A.L. Spek, G. van Koten, J.
Organomet. Chem. 583 (1999) 69.
[5] B. Richter, E. De Wolf, G. van Koten, B.J. Deelman, J. Mol.
Cat. 145 (1999) 317.
[6] R.A.T.M. Abbenhuis, I. del R´ıo, M.M. Bergshoef, J. Boersma,
N. Veldman, A.L. Spek, G. van Koten, Inorg. Chem. 37 (1998)
1750.
Et2O–pentane (1:5)
CSꢀPCy2ꢀ[Ru] was obtained.
a
brown viscous slurry of
1H-NMR (300 MHz, CD2Cl2): l=6.76–6.63 (m,
16H, ArH), 6.98 (t, 4H, J=7.5 Hz, ArHp, pyr), 6.36 (d,
8H, J=7.8 Hz, ArHm, pyr), 3.72 (s, 16H, CH2NMe2),
2.27 (s, 48H, N(CH3)2), 0.34 (s, 24H, SiMe).
31P{1H}-NMR (121 MHz, CD2Cl2): l=12.5
[7] A.W. van de Made, P.W.N.M. van Leeuwen, J. Chem. Soc.
Chem. Commun. 19 (1992) 1400.
[8] G0=tetraallylsilane; G0–SiMe2Cl=tetraallylsilane, silated with
HSiMe2Cl.
Acknowledgements
This work was supported by the Research Pro-
gramme of the Fund for Scientific Research-Flanders
[9] The different hydrogen and carbon atoms are labelled in Scheme
3.
.
.