Branched and dendritic metallo-carbosiloxanes with OCH2 PPh2MLn end-grafted units

Article abstract of DOI:10.1016/j.jorganchem.2004.08.022

A straightforward method for the preparation of metallo carbosiloxanes of type Si(OCH₂CH₂SiMe₂[OCH₂ PPh₂M(CO)_n])₄ (n = 3, M = Ni, 7a; n = 4, M = Fe, 7b; n = 5: M = Mo, 7c; M = W, 7d), Si(OCH₂ CH₂CH₂SiMe[OCH₂PPh₂Ni (CO)₃]₂)₄ (8) and Me₂ Si(OCH₂CH₂CH₂SiMe[OCH₂ PPh₂Ni(CO)₃]₂)₂ (11) is described. The reaction of Si(OCH₂CH₂CH₂ SiMeXCl)₄(1: X = Me, 2: X = Cl) or Me₂ Si(OCH₂CH₂CH₂SiMeCl₂) ₂)₂ (9) with HOCH₂PPh₂ (3) produces Si(OCH₂CH₂CH₂SiMe₂ (OCH₂PPh₂))₄ (4), Si(OCH₂ CH₂CH₂SiMe(OCH₂PPh₂) ₂)₄ (5) or Me₂Si(OCH₂ CH₂CH₂SiMe(OCH₂PPh₂) ₂)₂ (10) in presence of DABCO. Treatment of the latter molecules with Ni(CO)₄ (6a), Fe₂ (CO)₉ (6b), M(CO)₅ (Thf) (6c: M = Mo; 6d: M = W), respectively, gives the title compounds 7a-7d, 8 and 11 in which the PPh₂ groups are datively bound to a 16-valence-electron metal carbonyl fragment. The formation of analytical pure and uniform branched and dendritic metallo-carbosiloxanes is based on elemental analysis, and IR, ¹H, ¹³C{¹H}, ²⁹Si {¹H} and ³¹P{¹H} NMR spectroscopic studies. In addition, ESI-TOF mass spectrometric studies were carried out.

Full text of DOI:10.1016/j.jorganchem.2004.08.022

Journal of Organometallic Chemistry 689 (2004) 3598–3603
www.elsevier.com/locate/jorganchem
Branched and dendritic metallo-carbosiloxanes with
OCH2PPh2MLn end-grafted units
*
Heinrich Lang , Bettina Luhmann, Roy Buschbeck
¨
Technische Universita¨t Chemnitz, Fakulta¨t fu¨r Naturwissenschaften, Institut fu¨r Chemie, Lehrstuhl Anorganische Chemie,
Straße der Nationen 62, D-09111 Chemnitz, Germany
Received 26 April 2004; accepted 27 July 2004
Available online 16 September 2004
Abstract
A straightforward method for the preparation of metallo carbosiloxanes of type Si(OCH2CH2CH2SiMe2[OCH2PPh2M(CO)n])4
(n = 3, M = Ni, 7a; n = 4, M = Fe, 7b; n = 5: M = Mo, 7c; M = W, 7d), Si(OCH2CH2CH2SiMe[OCH2PPh2Ni(CO)3]2)4 (8) and
Me2Si(OCH2CH2CH2SiMe[OCH2PPh2Ni(CO)3]2)2 (11) is described. The reaction of Si(OCH2CH2CH2SiMeXCl)4 (1: X = Me, 2:
X = Cl) or Me2Si(OCH2CH2CH2SiMeCl2)2 (9) with HOCH2PPh2 (3) produces Si(OCH2CH2CH2SiMe2(OCH2PPh2))4 (4),
Si(OCH2CH2CH2SiMe(OCH2PPh2)2)4 (5) or Me2Si(OCH2CH2CH2SiMe(OCH2PPh2)2)2 (10) in presence of DABCO. Treatment
of the latter molecules with Ni(CO)4 (6a), Fe2(CO)9 (6b), M(CO)5(Thf) (6c: M = Mo; 6d: M = W), respectively, gives the title com-
pounds 7a–7d, 8 and 11 in which the PPh2 groups are datively bound to a 16-valence-electron metal carbonyl fragment.
The formation of analytical pure and uniform branched and dendritic metallo-carbosiloxanes is based on elemental analysis, and IR,
1H, 13C{1H}, 29Si{1H} and 31P{1H} NMR spectroscopic studies. In addition, ESI-TOF mass spectrometric studies were carried out.
Ó 2004 Elsevier B.V. All rights reserved.
Keywords: Metallo dendrimer; Carbosiloxane; Phosphane; Metal carbonyl; Nickel; Iron; Molybdenum; Tungsten
1. Introduction
We here report on the synthesis of Ph2PCH2O-func-
tionalised carbosiloxanes and carbosiloxane dendrimers
which on their reaction with diverse transition metal car-
bonyls give the respective metallo compounds.
There is a wide interest in the synthesis of metallo
dendrimers, since such three-dimensional and highly
branched molecules successfully can be used as, for
example, interface between homogenous and heteroge-
neous catalysis [1]. One possible entry into such catalytic
active materials is given by the fixation of catalytical ac-
tive sites at the periphery of soluble macromolecular
supports, for example, carbosilane dendrimers function-
alized with arylnickel(II) moieties [2]. Another approach
to synthesise metallo dendrimers is given by the intro-
duction of terminal-bound R2P groups (R = singly
bound organic ligand), which can later be used for the
complexation of the organometallic part [3].
2. Results and discussion
The target of this study is the synthesis of organome-
tallic carbosiloxanes and respective dendrimers featur-
ing M(CO)n fragments (n = 3, M = Ni; n = 4, M = Fe;
n = 5: M = Mo, W) as end-grafted units. They are acces-
sible in a two-step synthesis procedure. Exhaustive alco-
holysis of Si(OCH2CH2CH2SiMeXCl)4 (1: X = Me, 2:
X = Cl) [4] with HOCH2PPh2 (3) in presence of DABCO
(DABCO = diazabicyclooctane) in toluene at 25 °C pro-
duces Si(OCH2CH2CH2SiMe2(OCH2PPh2))4 (4) and
Si(OCH2CH2CH2SiMe(OCH2PPh2)2)4 (5).
*
Corresponding author.
E-mail address: heinrich.lang@chemie.tu-chemnitz.de (H. Lang).
0022-328X/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2004.08.022

H. Lang et al. / Journal of Organometallic Chemistry 689 (2004) 3598–3603
3599
(3)
Me
HO
PPh2
/
DABCO
6a - 6d
Si
O
SiMeXCl
Si
O
SiO
X´
PPh2
Si
O
Si O
Me2
PPh2
-DABCO*HCl
4
4
4
1: X = Me
2: X = Cl
4: X´ = Me
4
5: X´ = OCH2PPh2
PPh2
O
M(CO)n
PPh2
SiMe2
O
Me
Si
2
O
Me2
Si
Ph2P
O
O
Si
O
O
Si
O
PPh2
Me2
O
Ph2
P
Me2
Si
(CO)n M
O
O Si O
O
Si
O
P
M(CO)n
Ph2
Me2
SiMe2
O
4
Ph2P
Me
2Si
ð1Þ
Molecules 4 and 5 can be isolated in analytical pure
O
7a - 7d
Ph2P
M(CO)n
form by filtration through a pad of Celite and evapora-
tion of all volatile materials in oil-pump vacuum.
Compounds 4 and 5 contain Ph2P ligated units,
which allow the coordination of transition metal frag-
ments. In this respect, 4 and 5 were reacted with
Ni(CO)4 (6a), Fe2(CO)9 (6b) or M(CO)5(Thf) (6c:
M = Mo, 6d: M = W) in a 1:4 (reaction of 4 with 6) or
1:8 (reaction of 5 with 6) molar ratio in tetrahydrofuran
at 25 °C. Upon loss of CO (from 6a), Fe(CO)5 (from 6b)
or Thf (from 6c, 6d) the metallo carbosiloxanes
Si(OCH2CH2CH2SiMe2[OCH2PPh2M(CO)n])4 (n = 3,
M = Ni, 7a; n = 4, M = Fe, 7b; n = 5: M = Mo, 7c;
M = W, 7d) and dendrimer Si(OCH2CH2CH2Si-
Me[OCH2PPh2Ni(CO)3]2)4 (8) (Fig. 1) are formed in
excellent yield (Eq. (2)) (Table 1)
ð2Þ
The basic outline for the preparation of 4, 5, 7 and 8
with a SiO4 core (vide supra) can also be applied for the
synthesis of the cauliflower-type dendritic molecule Me2-
Si(OCH2CH2CH2SiMe[OCH2PPh2Ni(CO)3]2)2 (11).
Ph2
P
Me2Si
O
SiMeCl2
Ni(CO)3
2
O
Me
9
Si
O
P
Ph2
Ni(CO)3
O
O
HO
1)
PPh2 (3) DABCO
/
Me2Si
2) Ni(CO)4 (6a)
Ph2
P
Ni(CO)3
O
Si
Me
11
O
P
Ph2
Ni(CO)3
Ni(CO)3
PPh2
(CO)3Ni
Ph2P
ð3Þ
Dendritic 11 can be synthesised in the same way as 7
and 8 by alcoholysis of Me2Si(OCH2CH2CH2SiMeCl2)2-
(9) with HOPPh2 (3). The thus obtained Me2Si-
(OCH2CH2CH2SiMe(OCH2PPh2)2)2 (10) species reacts
with four equivalents of Ni(CO)4 (6a) to produce 11
by loss of carbon monoxide.
O
O
O
O
O
Si
Me
Ni(CO)3
Ni(CO)3
Ph2
P
(CO)3Ni
(CO)3Ni
Ph2
P
O
O
Si
O
O
O
Me
Si
Si
Me
O
P
Ph2
P
Ph2
Me
O
Table 1
Synthesis of 7a–7d
Si
Compound
M
n
Yielda (%)
Ph2P
(CO)3Ni
PPh2
Ni(CO)3
7a
7b
7c
7d
a
Ni
Fe
Mo
W
3
4
5
5
99
94
76
79
8
Fig. 1. Schematic view of dendrimer 8.
Based on 4.

3600
H. Lang et al. / Journal of Organometallic Chemistry 689 (2004) 3598–3603
Like the Ph2PCH2O-modified systems 4, 5 and 10
M(CO)n (n = 3, M = Ni; n = 4, M = Fe; n = 5, M = Mo,
W) in carbosiloxane molecules by the formation of da-
tive phosphorus–metal bonds. The respective metallo
carbosiloxanes and metallo dendrimers are obtained in
excellent yield and resemble the first examples in carbo-
siloxane dendrimer chemistry, featuring transition metal
carbonyl moieties as end-grafted units.
also their metal-containing derivatives 7a–7d, 8 and 11
are viscous oils. After appropriate work-up they can
be isolated as colourless (4), pale yellow (5, 7a, 7c, 7d,
8, 11) or orange (7b) oils in 75–99% yield and are soluble
in most common organic solvents.
Compounds 4, 5, 7, 8, 10 and 11 are fully character-
1
ised by IR, H, 13C{1H} and 31P{1H} NMR spectros-
copy. Additionally, 29Si{1H} NMR spectroscopic
studies were carried out with 4, 5, 7b and 10.
3. Experimental
Representative absorptions for all new synthesised
species are observed for the SiO units between 1070
and 1095 cmꢀ1 and for the CO building blocks in the
range of 1930–2070 cmꢀ1. The absorption pattern and
location of the mCO vibrations are in accordance with
similar literature-known (R3P)M(CO)n compounds
(M(CO)n = Ni(CO)3, Fe(CO)4, Mo/ W(CO)5; R = singly
bound organic ligand) [5]. Further distinct vibrations are
observed at ca. 1255 cmꢀ1 for the Si–C bonds.
Besides IR spectroscopy, 31P{1H} NMR studies are
best suitable to monitor the progress of the alcoholysis
and complexation steps. The Ph2PCH2O groups in 4,
5 and 10 give rise to a 31P{1H} NMR resonance sig-
nal at ꢀ12.2 (4, 5) or ꢀ11.9 ppm (10). Complexation
of the latter units by M(CO)n leads to a shift to lower
field depending on the respective metal carbonyls used
(7a, 8 and 11: ca. 30.0, 7b: 77.9, 7c: 35.5, 7d: 17.3
ppm). These data are in agreement with similar
R3PM(CO)n species [5,6].
3.1. General methods
All manipulations were performed in dry solvents un-
der an atmosphere of purified nitrogen (O2 traces: cop-
per catalyst, BASF AG, Ludwigshafen; H2O:
˚
molecular sieve 4 A, Roth) using standard Schlenk tech-
niques. Solvents were freshly purified and dried by distil-
lation. Diethyl ether and tetrahydrofuran: sodium/
benzophenone. Toluene: sodium. Celite (Errg. B6, Rie-
del de Ha¨en), degassed at 10ꢀ2 mbar and 25 °C, was
used for filtration procedures. IR spectra were recorded
with a Perkin–Elmer FT-IR 1000 spectrometer as films
between NaCl plates or as solutions in CaF2 cells,
respectively. The NMR spectra were measured in CDCl3
˚
or CD3CN (dried over 4 A molecular sieve) with a Bru-
ker Avance 250 spectrometer at 298 K: 1H NMR
(250.130 MHz), internal standard CDCl3, d = 7.26;
CD3CN, d = 1.94; 13C{1H} NMR: (62.902 MHz), inter-
nal standard CDCl3, d = 77.2; CD3CN, d = 1.24, 118.10;
29Si{1H} NMR (49.662 MHz) external standard, rela-
tive to SiMe4, d = 0.0; 31P{1H} NMR (101.202 MHz)
external standard H3PO4 (d = 0.0), relative to
P(OCH3)3, d = 139.0. Elemental analyses were per-
formed by the Organic Department of Chemnitz, Tech-
nical University with a Vario EL C,H,N-analyser
(Heraeus). The ESI-TOF mass spectra were measured
with a Mariner mass spectrometer (Applied Biosystems)
operating in the positive ion mode in the range of 3.0–
6.0 kV. As solvent acetonitrile or tetrahydrofuran was
used. For doping AgSCN was added.
In addition to 31P{1H} NMR spectroscopy the corre-
sponding transformation from SiMe2Cl- or SiMeCl2-
functionalised carbosiloxanes to Ph2PCH2O-modified
branched and dendritic molecules is nicely confirmed
1
by H and 13C{1H} NMR studies. New resonance pat-
terns, due to the Ph2PCH2O fragments appear in the
1H NMR spectra between 7.2 and 7.6 ppm (Ph) and at
ca. 4.3 ppm (OCH2P). In the 13C{1H} NMR spectra
characteristic resonance signals are observed between
128.0 and 137.5 ppm (Ph) and at approximately 65
ppm (OCH2P). For the CH2 unit of the OCH2PPh2 frag-
ments typical PH (1H NMR) and PC (13C{1H} NMR)
coupling constants are observed. Specific for the
M(CO)n-functionalised molecules is that in the
13C{1H} NMR spectra the CO resonance signals are ob-
served between 196 and 214 ppm, depending on the cor-
responding metal carbonyl building block present.
ESI-TOF mass spectrometric studies of selected
examples (4, 5 and 7) were carried out. It appeared that
for the Ni(CO)3-modified molecules no spectra could be
obtained, while for 7b the ions M+ ꢀ 4CO and
M+ ꢀ 4(PPh2Fe(CO)4) could be detected. For 4 it was
necessary to dope with AgSCN for a better ionisation.
As result thereof, [M + Ag]+ as molecular ion and
[M + Ag ꢀ 2(Ph2PCH2OMe)]+ are found.
3.2. Starting materials
Compounds 1, 2, 4 and 9 were prepared according to
well established literature procedures [4,7]. All other
chemicals were obtained commercially and were used
without further purification.
3.3. Synthesis of Si(OCH2CH2CH2SiMe2(OCH2P-
Ph2))4 (4)
1.73 g (8.00 mmol) of HOCH2PPh2 (3) are dissolved
in 50 mL of toluene and 0.45 g (4.00 mmol) of DABCO
are added in one portion. Afterwards 1.26 g (2.00 mmol)
of 1, dissolved in 2 mL of toluene, are added to the latter
In this study it could be shown that Ph2PCH2O enti-
ties allow the successful introduction of metal carbonyls

H. Lang et al. / Journal of Organometallic Chemistry 689 (2004) 3598–3603
3601
reaction mixture. Immediately DABCO*HCl starts to
precipitate. After 15 h of stirring at 25 °C the reaction
mixture is filtrated through a pad of Celite and all vola-
tiles are evaporated in oil-pump vacuum at 55 °C. Com-
pound 4 is obtained as a colourless, air sensitive, viscous
oil. Yield: 2.35 g (1.7 mmol, 87% based on 1).
IR (CaF2) m [cmꢀ1]: 2069 (s), 1997 (vs) [mC„O], 1256
(vs) [dSi–C], 1093 (vs) [mSi–O]. H NMR (CDCl3): d 0.04
1
(s, 24 H, SiMe), 0.4–0.7 (m, 8 H, SiOCH2CH2CH2SiO),
1.3–1.8 (m, 8 H, SiOCH2CH2CH2SiO), 3.5–3.9 (m, 8 H,
SiOCH2CH2CH2SiO), 4.4 (bs, 8 H, SiOCH2P), 7.2–7.8
(m, 40 H, Ph). 13C{1H} NMR (CDCl3): d ꢀ2.8 (SiMe),
11.6 (SiOCH2CH2CH2SiO), 25.8 (SiOCH2CH2CH2-
SiO), 64.4 (d, JPC = 29.4 Hz, SiOCH2P), 66.4
(SiOCH2CH2CH2SiO), 128.9 (d, JPC = 9.6 Hz, mC/Ph),
130.3 (pC/Ph), 133.2 (d, JPC = 14.0 Hz, oC/Ph), 134.8
IR (NaCl) m [cmꢀ1]: 1252 (vs) [dSi–C], 1074 (vs) [mSi–O].
1H NMR (CDCl3): d 0.00 (s, 24 H, SiMe), 0.3–0.6 (m, 8
H, SiOCH2CH2CH2SiO), 1.4–1.7 (m, 8 H, SiOCH2-
CH2CH2SiO), 3.5–3.7 (m, 8 H, SiOCH2CH2CH2SiO),
4.30 (d, 8 H, JPH = 5.8 Hz, SiOCH2P), 7.0–7.5 (m, 40 H,
Ph). 13C{1H} NMR (CDCl3): d ꢀ2.2 (SiMe), 11.8
(SiOCH2CH2CH2SiO), 26.0 (SiOCH2CH2CH2SiO),
66.1 (d, JPC = 5.3 Hz, SiOCH2P), 68.3 (SiOCH2CH2CH2-
SiO), 128.2 (d, JPC = 6.7 Hz, mC/Ph), 128.5 (pC/Ph),
132.9 (d, JPC = 17.7 Hz, oC/Ph), 137.2 (d, JPC = 11.5 Hz,
iC/Ph). 29Si{1H} NMR (CDCl3): d ꢀ81.8 (SiO4), 20.6
(SiO). 31P{1H} NMR (CDCl3): d ꢀ12.2. ESI-TOF [m/z]
(rel. int.): [M + Ag]+ 1461(12), [M + Ag ꢀ Me2OCH2-
PPh2]+ 1188 (100). Anal. Calc. for C72H96O8P4Si5
(1353.81); C, 63.87, H, 7.15. Found: C, 63.94, H, 7.11%.
i
(d, JPC = 32.5 Hz, C/Ph), 196.6 (CO). 29Si{1H} NMR
(CDCl3): d ꢀ81.9 (SiO4), 21.7 (d, JSiP = 7.3 Hz, SiO).
31P{1H} NMR (CDCl3): d 29.5. Anal. Calc. for
C84H96Ni4O20P4Si5 (1353.81); C, 52.42, H, 5.03. Found:
C, 52.27, H, 5.25%.
3.6. Synthesis of Si(OCH2CH2CH2SiMe2[OCH2PPh2-
Fe(CO)4])4 (7b)
0.29 g (0.80 mmol) of Fe2(CO)9 (6b) are added in one
portion to a solution originated of 0.27 g (0.20 mmol) of
4 in 30 mL of toluene. The orange suspension is stirred
for 15 h at 25 °C. Afterwards the almost clear solution is
filtrated through a pad of Celite and all volatiles are re-
moved from the eluate in oil-pump vacuum. Compound
7b is obtained as a orange-red oil of high viscosity in
0.38 g (0.18 mmol, 94% based on 4) yield.
IR (CaF2) m [cmꢀ1]: 2049, 1974, 1933 (vs) [mC„O]; 1254
(vs) [dSi–C]; 1096 (vs) [mSi–O]. 1H NMR (CDCl3): d 0.08 (s,
24 H, SiMe), 0.3–0.8 (m, 8 H, SiOCH2CH2CH2-SiO), 1.3–
1.8 (m, 8 H, SiOCH2CH2CH2SiO), 3.5–3.9 (m, 8 H,
SiOCH2CH2CH2SiO), 4.45 (d, 8 H, JPH = 13.5 Hz,
SiOCH2P), 7.3–7.8 (m, 40 H, Ph). 13C{1H} NMR
(CDCl3): d ꢀ2.7 (SiMe), 11.5 (SiOCH2CH2CH2SiO),
25.7 (SiOCH2CH2CH2SiO), 64.8 (d, JPC = 25.7 Hz,
3.4. Synthesis of Si(OCH2CH2CH2SiMe(OCH2P-
Ph2)2)4 (5)
Molecule 5 can be prepared by the procedure de-
scribed for 4. In this respect, 2.59 g (12.0 mmol) of
HOCH2PPh2 (3) and 0.67 g (6.0 mmol) of DABCO
are dissolved in 70 mL of toluene and 1.07 g (1.5 mmol)
of 2 are added in one portion. After appropriate
work-up, 5 can be obtained as a pale yellow oil of high
viscosity. Yield: 2.85 g (1.3 mmol, 88% based on 2).
IR (NaCl) m [cmꢀ1]: 1258 (vs) [dSi–C], 1079 (vs) [mSi–O].
1H NMR (CDCl3): d 0.00 (s, 12 H, SiMe), 0.4–0.6 (m, 8
H, SiOCH2CH2CH2SiO), 1.4–1.7 (m, 8 H, SiOCH2CH2-
CH2SiO), 3.6–3.8 (m, 8 H, SiOCH2CH2CH2SiO), 4.34 (d,
16 H, JPH = 5.8 Hz, SiOCH2P), 7.2–7.6 (m, 80 H, Ph).
13C{1H} NMR (CDCl3): d ꢀ4.6 (SiMe), 9.9 (SiOCH2-
CH2CH2SiO), 26.0 (SiOCH2CH2CH2SiO), 63.7 (d,
JPC = 7.2 Hz, SiOCH2P), 66.5 (SiOCH2CH2CH2SiO),
128.7 (d, JPC = 6.7 Hz, mC/Ph), 129.2 (pC/Ph), 132.9 (d,
SiOCH2P), 65.9 (SiOCH2CH2CH2SiO), 128.4 (d, JPC
=
10.1 Hz, mC/Ph), 129.0 (pC/Ph), 130.8 (d, JPC = 17.7
o
i
Hz, C/Ph), 132.8 (d, JPC = 11.5 Hz, C/Ph), 213.2 (d,
2JPC = 19.2 Hz, CO). 31P{1H} NMR (CDCl3): d 77.9.
ESI-TOF [m/z] (rel. int.): [M+ ꢀ 4CO] 1913 (1), [M+ ꢀ
4PPh2Fe(CO)4]
1761
(20).
Anal.
Calc.
for
o
i
JPC = 17.7 Hz, C/Ph), 137.0 (d, JPC = 12.4 Hz, C/Ph).
29Si{1H} NMR (CDCl3): d ꢀ81.8 (SiO4), ꢀ1.0 (SiO2).
31P{1H} NMR (CDCl3): d ꢀ12.2. Anal. Calc. for
C88H96Fe4O24P4Si5 (2025.334); C, 52.18, H, 4.77. Found:
C, 51.73, H, 4.98%.
C
120H132O12P8Si5 (2154.48); C, 66.89, H, 6.18. Found:
C, 66.76, H, 6.25%.
3.7. Synthesis of Si(OCH2CH2CH2SiMe2[OCH2PPh2-
Mo(CO)5])4 (7c)
3.5. Synthesis of Si(OCH2CH2CH2SiMe2[OCH2PPh2-
Ni(CO)3])4 (7a)
0.26 g (1.00 mmol) of Mo(CO)6 are dissolved in 100
mL of tetrahydrofuran and the solution is irritiated with
a high pressure mercury lamp for 5 h in a photolysis
reactor. A slow continuous stream of N2 is bubbled
through the reaction mixture to remove the CO. To
the thus obtained Mo(CO)5(Thf) (6c) species, 0.24 g
(0.18 mmol) of 4, dissolved in 20 mL of tetrahydrofuran,
are added in one portion. After 15 h of stirring at 25 °C
0.27 g (0.20 mmol) of 4 are dissolved in 20 mL of
diethyl ether and 0.21 g (1.20 mmol) of Ni(CO)4 (6a)
are added in one portion. After 90 min of stirring at
25 °C all volatile materials are removed in oil-pump vac-
uum leaving 7a as an orange, viscous oil. Yield: 0.38 g
(0.19 mmol, 99% based on 4).

3602
H. Lang et al. / Journal of Organometallic Chemistry 689 (2004) 3598–3603
the reaction mixture is filtrated through a pad of Celite
and all volatiles are removed in oil-pump vacuum. Ex-
cess of Mo(CO)6 is sublimed off in oil-pump vacuum
by using a cooling finger. 7c remains as analytical pure,
dark yellow oil of high viscosity. Yield 0.31 g (0.14
mmol, 76% based on 4).
(s, 12 H, SiMe), 0.4–0.7 (m, 8 H, SiOCH2CH2CH2SiO),
1.3–1.8 (m, 8 H, SiOCH2CH2CH2SiO), 3.5–3.9 (m, 8 H,
SiOCH2CH2CH2SiO), 4.3 (bs, 16 H, SiOCH2P), 7.3–7.8
(m, 80 H, Ph). 13C{1H} NMR (CDCl3): d ꢀ6.1 (SiMe),
8.7 (SiOCH2CH2CH2SiO), 24.4 (SiOCH2CH2CH2SiO),
63.4 (d, JPC = 30.7 Hz, SiOCH2P), 65.4 (SiOCH2-
CH2CH2SiO), 128.3 (d, JPC= 9.6 Hz, mC/Ph), 129.8
(pC/Ph), 132.5 (d, JPC = 12.3 Hz, oC/Ph), 133.7 (d,
JPC = 33.1 Hz, iC/Ph), 196.0 (CO). 31P{1H} NMR
(CDCl3): d 30.5. Anal. Calc. for C144H132Ni8O36P8Si5
(3296.19); C, 52.40, H, 4.04. Found: C, 53.33, H, 4.35%.
IR (CaF2) m [cmꢀ1] 2072 (w), 1988 (w), 1945 (vs)
[mC„O]; 1252 (vs) [dSi–C]; 1074 (vs) [mSi–O]. 1H NMR
(CDCl3): d ꢀ0.08 (s, 24 H, SiMe), 0.5–0.7 (m, 8 H,
SiOCH2CH2CH2SiO), 1.4–1.7 (m, 8 H, SiOCH2CH2CH2-
SiO), 3.6–3.9 (m, 8 H, SiOCH2CH2CH2SiO), 4.25 (d, 8
H, JPH = 60 Hz, SiOCH2P), 7.4–7.7 (m, 40 H, Ph).
13C{1H} NMR (CDCl3): d ꢀ2.9 (SiMe), 10.7 (SiOCH2-
CH2CH2SiO), 25.7 (SiOCH2CH2CH2SiO), 65.0 (d,
JPC = 33.5 Hz, SiOCH2P), 65.9 (SiOCH2CH2CH2SiO),
128.5 (d, JPC = 9.1 Hz, mC/Ph), 129.0 (pC/Ph), 130.1 (d,
3.10. Synthesis of Me2Si(OCH2CH2CH2SiMe(OCH2-
PPh2))2 (10)
Compound 10 can be prepared as described earlier
for 4 (vide supra). In this respect 1.04 g (4.80 mmol)
of 3, 0.27 g (2.40 mmol) of DABCO and 0.48 g (1.20
mmol) of 9 are reacted. After appropriate work-up 10
can be isolated as a colourless, air sensitive viscous oil.
Yield: 1.15 g (1.02 mmol, 86% based on 9).
o
i
JPC = 11.5 Hz, C/Ph), 132.3 (d, JPC = 34.5 Hz, C/Ph),
205.7 (d, JPC = 9.1 Hz, cis-CO), 210.1 (d, JPC = 12.5 Hz,
trans-CO). 31P{1H} NMR (CDCl3): d 35.5. Anal. Calc.
for C92H96Mo4O28P4Si5 (2297.74); C, 48.09, H, 4.21.
Found: C, 48.27, H, 4.57%.
IR (NaCl) m [cmꢀ1]: 1257 (vs) [dSi –C], 1068 (vs) [mSi–O].
1H NMR (CDCl3): d 0.02, 0.1 (12 H, Me2SiOCH2-
CH2CH2SiMe), 0.2–0.4 (m, 4 H, SiOCH2CH2CH2SiO),
1.7–1.9 (m, 4 H, SiOCH2CH2CH2SiO), 3.7–3.9 (m, 4 H,
SiOCH2CH2CH2SiO), 4.30 (d, 8 H, JPH = 5.8 Hz,
SiOCH2P), 7.2–7.6 (m, 40 H, Ph). 13C{1H} NMR
(CDCl3): d ꢀ4.7, ꢀ2.7 (Me2SiOCH2CH2CH2SiMe), 9.9
(SiOCH2CH2CH2SiO), 26.1 (SiOCH2CH2CH2SiO),
63.6 (d, JPC = 8.1 Hz, SiOCH2P), 65.2 (SiOCH2CH2CH2-
SiO), 128.7 (d, JPC = 6.7 Hz, mC/Ph), 129.1 (pC/Ph), 133.6
(d, JPC = 18.2 Hz, oC/Ph), 136.9 (d, JPC = 12.0 Hz, iC/Ph).
29Si{1H} NMR (CDCl3): d ꢀ3.7, ꢀ2.4 (Me2SiO2, Me-
SiO2). 31P{1H} NMR (CDCl3): d ꢀ11.9. Anal. Calc. for
C62H72O6P4Si3 (1121.46); C, 66.40, H, 6.47. Found: C,
66.39, H, 6.52%.
3.8. Synthesis of Si(OCH2CH2CH2SiMe2[OCH2PPh2-
W(CO)5])4 (7d)
0.35 g (1.00 mmol) of W(CO)6 and 0.24 g (0.18 mmol)
of 4 are reacted as described for the preparation of 7c.
Appropriate work-up gives a yellow oil of high viscosity.
Yield: 0.38 g (0.14 mmol, 79% based on 4).
IR (CaF2) m [cmꢀ1]: 2071 (w), 1979 (w), 1943 (vs)
[mC„O]; 1252 (vs) [dSi–C]; 1074 (vs) [mSi–O]. 1H NMR
(CDCl3): d ꢀ0.02 (s, 24 H, SiMe), 0.4–0.7 (m, 8 H,
SiOCH2CH2CH2SiO), 1.4–1.8 (m, 8 H, SiOCH2CH2CH2-
SiO), 3.6–3.9 (m, 8 H, SiOCH2CH2CH2SiO), 4.25 (d, 8
H, JPH = 67.5 Hz, SiOCH2P), 7.2–7.7 (m, 40 H, Ph).
13C{1H} NMR (CDCl3):
(SiOCH2CH2CH2SiO), 25.6 (SiOCH2CH2CH2SiO),
d
ꢀ3.1 (SiMe), 11.7
63.0
(d,
JPC = 37.9
Hz,
SiOCH2P),
66.0
3.11. Synthesis of Me2Si(OCH2CH2CH2SiMe[OCH2P-
Ph2Ni(CO)3]2)2 (11)
(SiOCH2CH2CH2SiO), 128.5 (d, JPC= 9.6 Hz, mC/Ph),
129.0 (pC/Ph), 130.3 (d, JPC= 10.6 Hz, C/Ph), 133.8 (d,
o
i
JPC = 40.3 Hz, C/Ph), 196.7 (d, JPC = 8.2 Hz, cis-CO),
In a similar manner to the preparation of 7a, 0.20 g
(0.18 mmol) of 10 are reacted with 0.18 g (1.08 mmol)
of Ni(CO)4 (6a) in diethyl ether. Appropriate work-up
gives the metallo dendrimer 11 as a pale yellow viscous
oil in 0.29 g (0.15 mmol, 93% based on 10) yield.
IR (NaCl) m [cmꢀ1]: 2070 (s), 1997 (vs) [mC„O]; 1257
199.1 (d, JPC = 21 Hz, trans-CO). 31P{1H} NMR
(CDCl3): d 17.3. Anal. Calc. for C92H96O28P4Si5W4
(2649.47); C, 41.70, H, 3.65. Found: C, 42.61, H, 3.93%.
3.9. Synthesis of Si(OCH2CH2CH2SiMe[OCH2PPh2-
Ni(CO)3]2)4 (8)
1
(vs) [dSi–C]; 1068 (vs) [mSi–O]. H NMR (CDCl3): d 0.17,
0.29 (m, 12 H, Me2SiOCH2CH2CH2SiMe), 0.6–0.8 (m,
Dendrimer 8 can be synthesised by following the pro-
cedure described for the synthesis of 7a. Thus, 0.35 g
(0.16 mmol) of 5 are reacted with 0.33 g (1.92 mmol)
of Ni(CO)4 (6a). After appropriate work-up the title
compound can be isolated as a yellow viscous oil. Yield:
0.51 g (0.15 mmol, 94% based on 5).
4
H, SiOCH2CH2CH2SiO),1.6–1.9 (m,
4
H,
SiOCH2CH2CH2SiO),3.1–3.5 (m, 4 H, SiOCH2CH2-
CH2SiO), 4.3 (bs, 8 H, SiOCH2P), 7.4–7.9 (m, 40 H,
Ph). 13C{1H} NMR (CDCl3): d ꢀ3.7, ꢀ3.1 (Me2-
SiOCH2CH2CH2SiMe),8.8 (SiOCH2CH2CH2SiO), 25.6
(SiOCH2CH2CH2SiO), 62.3 (d, JPC = 28.1 Hz,
SiOCH2P), 65.8 (SiOCH2CH2CH2SiO), 128.3 (d,
JPC = 9.1 Hz, mC/Ph), 129.8 (pC/Ph), 132.6 (d,
IR (CaF2) m [cmꢀ1]: 2069 (s), 1984 (vs) [mC„O]; 1256
1
(vs) [dSi–C]; 1093 (vs) [mSi–O]. H NMR (CDCl3): d 0.00

H. Lang et al. / Journal of Organometallic Chemistry 689 (2004) 3598–3603
i
3603
o
[2] For example: J.W.J. Knapen, A.W. van der Made, J.C. de Wilde,
P.W. van Leeuwen, D.M. Grove, G. van Koten, Nature 372
(1994) 659.
JPC = 12.9 Hz, C/Ph), 134.1 (d, JPC = 32.6 Hz, C/Ph),
195.5 (CO). 31P{1H} NMR (CDCl3): d 28.7. Anal. Calc.
for C74H72Ni4O20P4Si3 (1724.21); C, 42.92, H, 4.21.
Found: C, 43.79, H, 4.30%.
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Acknowledgements
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Ed. Engl. 36 (1997) 1526;
We are grateful to the Deutsche Forschungsge-
meinschaft for financial support.
(e) M.T. Reetz, G. Lohner, R. Schwickardi, Angew. Chem. 109
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