Synthesis, coordination chemistry and polymerfixation of the tripod-ligand HOC6H4CH2C(CH2PPh2) 3

Article abstract of DOI:10.1016/S0022-328X(98)00883-3

Starting from 4-methoxybenzylmalonic ester MeOC₆H₄CH₂CH(COOEt)₂, the synthesis of the tripod-ligand HOC₆H₄CH₂C(CH₂PPh₂) ₃, 12, functionalized with a phenolic group at its backbone, is achieved in a few steps. Ether derivatives of 12 show the normal coordination behavior of RC(CH₂PPh₂)₃. Thus MeOC₆H₄CH₂C(CH₂PPh₂) ₃ forms the complexes [7·Fe(NCMe)₃] (BF₄)₂ (8) and 7·Mo(CO)₃ (9). The phenolate derived from 12 by deprotonation reacts with the CH₂Cl groups of Merrifield resin to form covalently polymer fixed 12 with high efficiency. The polymer bound tripod ligands undergo tripod typical coordination reactions. In addition to the usual spectroscopic and analytical techniques, X-ray analyses of derivatives of 12 as well as of 8 and 9 are used to identify the products.

Full text of DOI:10.1016/S0022-328X(98)00883-3

Journal of Organometallic Chemistry 571 (1998) 279–288
Synthesis, coordination chemistry and polymerfixation of the
1
tripod-ligand HOC6H4CH2C(CH2PPh2)3
Peter Schober, Gottfried Huttner *, Laszlo Zsolnai, Albrecht Jacobi
Anorganisch-Chemisches Institut der Uni6ersita¨t Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
Received 16 June 1998
Abstract
Starting from 4-methoxybenzylmalonic ester MeOC6H4CH2CH(COOEt)2, the synthesis of the tripod-ligand
HOC6H4CH2C(CH2PPh2)3, 12, functionalized with a phenolic group at its backbone, is achieved in a few steps. Ether derivatives
of 12 show the normal coordination behavior of RC(CH2PPh2)3. Thus MeOC6H4CH2C(CH2PPh2)3 forms the complexes
[7·Fe(NCMe)3] (BF4)2 (8) and 7·Mo(CO)3 (9). The phenolate derived from 12 by deprotonation reacts with the CH2Cl groups
of Merrifield resin to form covalently polymer fixed 12 with high efficiency. The polymer bound tripod ligands undergo tripod
typical coordination reactions. In addition to the usual spectroscopic and analytical techniques, X-ray analyses of derivatives of
12 as well as of 8 and 9 are used to identify the products. © 1998 Elsevier Science S.A. All rights reserved.
Keywords: Polymer bound ligands; Functionalized tripod ligands; Molybdenum complexes; Iron complexes
1. Introduction
[3]. The sluggish reactivity of the neopentane system
and the short spacer separating the OH group from its
tertiary carbon atom preclude the application of this
strategy for the fixation of neopentane based ligands on
polymers. We report here on the synthesis of
HOC6H4CH2C(CH2PPh2)3, 12 the phenolic hydroxy
group of which is separated from the tertiary carbon
atom by a benzyl type spacer. From malonic ester
precursors ([2]a) 12 is obtained in five steps with a fair
overall yield of 35%. It is shown that ethers derived
from 12 have the full coordinating capability of the
parent compound CH3C(CH2PPh2)3. Results of cova-
lently fixing 12 to Merrifield resin are reported.
Neopentane
based
tripod-ligands
RCH2C(CH2X)(CH2Y)(CH2Z) have a well documented
and sometimes peculiar coordination chemistry which
has quite some promises in the field of catalysis as well
[1]. To make full use of their specific properties, a
possibility to link these tripodal ligands to auxiliary
groups of different types would be welcome. Only a few
specialised syntheses leading to distinct derivatives
RCH2C(CH2PPh2)3 species had been reported in the
past ([2]b, h, j). It has recently been found [3] that the
neopentane bound hydroxy group of tripod ligands
HOCH2C(CH2X)(CH2Y)(CH2Z) may serve as a linker
entity via ether formation under rather specialised con-
ditions which avoid the attack of the neopentane bound
donor groups X, Y, Z by the ether forming electrophile
2. Results and discussion
To formally insert a phenyl-spacer into the backbone
of HOCH2C(CH2PPh2)3, easily achieveable 4-methoxy-
benzyl-malonicester [4] is deprotonated with sodium
hydride and alkylated with chloromethyl-benzylether [5]
to form 1. The diester 1 is transformed into the diol 2
* Corresponding author. Tel.: +49 6221 548446; fax: +49 6221
545707.
1 Dedicated to Professor Dr Hermann Irngartinger on the occasion
of his 60th birthday.
0022-328X/98/$ - see front matter © 1998 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00883-3

280
P. Schober et al. / Journal of Organometallic Chemistry 571 (1998) 279–288
An interesting observation is made with respect to the
torsion angles characterizing the conformations of four
different tripod ligands of the general formula
RCH2C(CH2PPh2)3. In all four cases studied so far
(Table 1), the rotational positions of the four groups
radiating from the central carbon atom C4 with respect
to their rotation around the corresponding C4–CH2
bonds is very much alike in so far as an almost stag-
gered conformation is approached at any C–C bond
(torsion angles around 960 and 180°, see Fig. 1, Table
1) [6]. In addition, the rotation of the aryl groups with
respect to the Cipso–C–(CH2) bonds is very close to 90°
for all compounds (Table 1). The fact that these
parameters describing the conformation of the core of
these compounds are invariant within a small angular
range must mean that this conformation is almost
exclusively determined by the inner molecular forces
and does not strongly depend on the forces acting upon
the molecules in their four different crystal
environments.
The problem of side reactions as observed in the
activation of 3 by SOCl2 is completely avoided when 3
is activated by PhSO2Cl, to form 6. The reaction of 6
with KPPh2 in DMSO results in a fair yield of the
desired product 7 (Scheme 4).
Even though there can be no question that 7 will
behave as a tripod ligand like other derivatives
RCH2C(CH2PPh2)3 ([2]a, b) the coordination com-
pounds 8 and 9 have been synthesized and fully charac-
terized with the reason for this being that the struc-
tural information obtained by X-ray analysis of such
compounds is highly valuable: in any attempt to de-
rive the rules governing the conformational arrange-
ment and flexibility of tripod-metal compounds [RCH2
C(CH2X)(CH2Y)(CH2Z)]MLn one has to rely on a
structural data base as broad as possible. Methods to
extract the relevant information from such databases
Scheme 1.
with LiAlH4. Cleavage of the benzylether with hydro-
gen and Pd/C leads to the triol 3, which can be acti-
vated either through chlorination or esterification
(Scheme 1).
The CH2OH groups in 3 are transformed into elec-
trophilically activated centers by standard procedures
(Scheme 2).
At temperatures above 10°C chlorination of the
arene ring in the 3-position becomes a noticeable side
reaction. Initially the reaction was performed at tem-
peratures above 25°C resulting in an almost 1:1 mixture
of 4a and 4b. It is not possible to separate 4a and its
ring-chlorinated derivative 4b by chromatography.
Therefore the mixture was immediately subjected to
phosphinilation in the hope that the resulting tripod
ligands might be separable (Scheme 3). It was observed
that under these conditions the methoxy function of 4b
is cleaved while as the experiments with 4a (see below)
show it is stable under these conditions when no ortho
chlorine function is present. The phenolic hydroxy
function of 5 resulting after hydrolytic workup in-
creases the differentation of 5 and 7 such that pure 5 is
obtained by crystallisation.
The structures of 5 and 7 have been determined by
X-ray analyses (Fig. 1, Table 1). There is nothing
special about individual distances and angles (Table 1).
Scheme 2.
Scheme 3.

P. Schober et al. / Journal of Organometallic Chemistry 571 (1998) 279–288
281
Fig. 1. Views of 5 and 7.
Table 1
Selected bond lengths (pm) and angles (°) of the ligands RCH2C(CH2PPh2)3
5 R=3-chloro-4-hydroxybenzyl
7 R=4-methoxybenzyl
R=phenyl ([2]b)
R=H ([1]i)
P–C(CH2)
185.5(2)–186.2(2)
185.3(2)–186.3(2)
184.9(5)–185.2(4)
185.1(5)–185.9(6)
P–C(Ar)
183.4(5)–184.8(5)
181.9(5)–183.5(5)
183.8(5)–185.5(5)
183.8(5)–185.6(5)
C4–CH2
153.8(3)–157.3(3)
154.5(3)–155.1(3)
154.9(6)–158.1(6)
153.6(7)–154.2(8)
C4–CH2–P
115.0(4)–116.2(4)
116.2(4)–117.2(4)
115.2(3)–117.7(3)
114.7(4)–118.7(4)
C1–C4–C5–Cipso
C4–C5–Cipso–Cortho
C5–C4–C1–P1
C5–C4–C2–P2
C5–C4–C3–P3
−173
89
−71
178
−178
91
61
67
−174
61
91
174
−63
−68
—
—
−79
−66
−176
−60
Estimated standard deviations of the least significant figures are given in parentheses.
have been developed [6] and the structures of 8 and 9
are helpful additions to these databases (Scheme 5).
Compound 8 is prepared in analogy to the synthesis
of other [(tripod)Fe(NCMe)3]2+ species ([2]b–f) from
[Fe(NCMe)6]2+ [7]. Compound 9 was likewise obtained
by applying the standard procedure ([2]f–i) starting
from (NCMe)3Mo(CO)3 [8].
Mo(CO)3 chromophores is evident from the w(CN)-
and w(CO)-IR data, respectively (experimental part).
NMR data as well as elemental analysis prove the
assigned constitutions which are further corroborated
by X-ray analyses (Table 2, Fig. 2).
Both compounds show the expected idealized octahe-
dral geometry with the tripod ligand occupying one
face of the octahedron (Fig. 2). The distances and
angles (Table 2) are well within the range known for
other [(tripod)Fe(NCMe)3] compounds ([2]b–f). The
torsional arrangements of the chelate scaffolding are
different with 8 showing one large torsion around 35°
and two medium torsions around 17° while 9 has three
large torsion angles (Table 2) and is comparable in this
respect to [{PhCH2C(CH2PPh2)3}Fe(NCMe)3]2+ ([2]c).
Both compounds are obtained in excellent yields, the
local C3 symmetry of the Fe(NCMe)3 as well as of the
Scheme 4.

282
P. Schober et al. / Journal of Organometallic Chemistry 571 (1998) 279–288
Scheme 5.
Refering to the torsion angles characterizing the rota-
elaborated. The methoxy group of 4a is transformed
into the phenolic hydroxy group of 10 with Me3SiI as
the activating reagent. 10 is obtained as a colorless
microcrystalline solid whose properties conform in all
points to its constitution as given. A further proof of its
identity is the straightforward transformation of 10 into
the ether 11 which is obtained as a colorless oil and is
as well fully characterized by all usual spectroscopic and
analytical techniques. The ease with which 10 undergoes
etherification is in stark contrast to the difficulties
opposing the etherification of HOCH2C(CH2Cl)3 ([2]h)
which are in part due to intermolecular cyclization
reactions. The phenyl spacer in 10 does not allow for
this type of intramolecular reaction. An intermolecular
reaction by condensation of CH2Cl groups with phe-
noxy-groups which might in principle be a problem is
not observed under the applied conditions (Scheme 6).
The reluctance to cyclysation reactions of the pheno-
late ion obtained from 10 by treatment with KOtBu is
a pre-requisite for the successful transformation of 10 to
the tripod ligand 12.
tional positions of the phenyl groups (Q–Pi–Cj–Ck,
Table 2) it is observed that there is one PPh2 group at
P1 in each of the compounds which has both its phenyl
rings in an orientation almost parallel to the idealized
C3 axes of the molecules (Fig. 2, Table 2). With respect
to the PPh2 group showing the small torsion angles the
sectors occupied by the benzyl group at the bridgehead
carbon are different in compounds 8 and 9 (Fig. 2). In
each case however one of the P bonded phenyl groups
in this occupied sector has a low torsion angle (Fig. 2).
Taken together the structural examples given show
that an alkoxy function in the para position of the
benzyl substituent at the bridgehead carbon of the
chelate cage does not strongly influence neither the
coordination capability nor the conformational behav-
ior of the ligands. This is a favorable observation with
respect to the idea of using a phenolic group at the
backbone of tripod ligands as a linker group.
For the synthesized ligands of this type the approach
described for the transformation of 1 to 4 was further
Table 2
Selected bond lenghts [pm] and angles [°] of 8 and 9a
b
b
c
d
8
9
8
9
8
9
M–P1
M–P2
M–P3
M–L1
M–L2
M–L3
227.6(1)
227.1(1)
225.0(1)
195.1(3)
195.6(3)
196.3(3)
253.6(2)
252.6(2)
250.8(2)
198.2(7)
197.8(7)
197.6(7)
P1–M–P2
P1–M–P3
P2–M–P3
L1–M–L2
L1–M–L3
L2–M–L3
C4–C5–C47
C44–O1–C48
91.7(4)
85.6(4)
90.4(4)
85.9(1)
86.7(1)
84.2(1)
83.1(1)
81.6(1)
84.8(1)
85.1(3)
83.9(3)
90.6(3)
C4–C1–P1–M
C4–C2–P2–M
C4–C3–P3–M
34.6
16.3
18.1
−5
8
27.7
30.6
39.7
−2
−1
−56
−45
−13
−33
88
36.6
35.5
27.8
7
Q–P1–C11–C6
Q–P1–C17–C12
Q–P2–C23–C18
Q–P2–C29–C24
Q–P3–C35–C30
Q–P3–C41–C36
C4–C5–C47–C42
C43–C44–O1–C48
−9
41
−27
−43
−5
89
75
—
116.5(3)
116.8(3)
116.8(5)
116.8(6)
−10
−22
−74
97
2
−10
a
Estimated standard deviations of the least significant figures are given in parentheses.
b The designators L1 are used to characterize the carbon or nitrogen atoms of the co-ligands. M specifies the metal center in each case.
c Q specifies the end point of a vector attached to the corresponding phosphorous center which points towards the observer with respect to the
projections of the compounds onto the P3 planes as given in Fig. 2 (top). The vector is vertical to the P3 plane.
d This column refers to the corresponding values for [{PhCH2C(CH2PPh2)3}Fe(NCMe)3]2+ ([2]c).

P. Schober et al. / Journal of Organometallic Chemistry 571 (1998) 279–288
283
Fig. 2. Two views of the structures of 8 and 9. Top view: projection onto the P3 plane.
Deprotonation of 10 by KOtBu and consequent reac-
tion with three equivalents of KPPh2 in DMSO leads to
a fair yield of 12. As a raw product, 12 is a colorless oil
which slowly transforms into a microcrystalline color-
less powder when its solution in Et2O is mixed with
PE40/60 in an ultrasonic bath over a few hours. As an
alternative way to obtain analytically pure 12 chro-
matography on silica gel has been found to work. The
Et2O/PE40/60 fraction containing 12 leaves the com-
pound as a microcrystalline colorless powder after
evaporation (Scheme 7).
The sequence of reactions from 1 to 12, as described,
implies six steps altogether. Even though, the overall
yield of 12 amounts to over 35%.
As a first test to validate the utility of the phenyl
spacer in 12 with respect to the problem of covalently
anchoring hydroxy-functionalized tripod-ligands on a
polymer the reaction of 12 with a CH2Cl-functionalized
polystyrene resin of the Merrifield type was analysed.
From the reactivity reported for HOCH2C(CH2PR2)3
([2]f, h) it is evident that this type of hydroxy function-
alized tripod-ligand could not be covalently fixed to a
CH2Cl-functionalized resin, because of the intermolecu-
lar cyclization reactions which are characteristic of this
type of compound under the conditions of etherifica-
tion ([2]h). Nevertheless a series of experiments was
done with the HOCH2-group of HOCH2C(CH2PR3)3 or
the ClCH2-group of ClCH2C(CH2PR2)3 as potential
precursors with respect to polymer fixation [9]. The 31P
resonances of the products obtained were however,
exclusively observed at l= +30, indicating that phos-
phorus instead of oxygen had been attacked as the
nucleophilic center [10]. Success in polymer fixation was
achieved with 12 as the tripod constituent.
To incorporate 12 into the polymer the resin-granu-
late as commercially available was allowed to swell in

284
P. Schober et al. / Journal of Organometallic Chemistry 571 (1998) 279–288
Scheme 6.
o-dichlorobenzene. A total of 1.4 equivalents (with
respect to the CH2Cl-groups of the polymer) of 12 and
correspondingly 1.4 equivalents of sodium hydride were
added to the suspension of the gel and the mixture was
heated to 70°C for a period of 5 days. After evapora-
tion of the solvent and extensive washing the resulting
powder was dried to constant weight. The increase in
weight was in accord with results obtained by microan-
alytic determination of the phosphorous content of the
powder. With 3.9% phosphorous found, ca. 60% of the
reactive groups must have been linked to the ligand
[11]. The 31P-NMR signal characteristic for the ligand
loaded resin is found at l= −27.7 for the gel prepared
from it by swelling in o-dichlorobenzene. The value of
the observed chemical shift is thus identical to the one
observed for the free precursor 12. There are no other
31P-NMR signals in the spectrum of the gel which
clearly proves that no quarternization by electrophilic
attack at the phosphorous centers had occurred. Phos-
phonium salts if they were formed would lead to reso-
nances at around l= +30 ([2]f). In order to directly
visualize the covalent linkage between the tripod ligand
and the resin, the latter was subjected to conditions
under which [(tripod)Fe(NCMe)3]2+ ([2]c) and
[(tripod)Co(catecholate)]+ ([1]h) complexes are ob-
tained from free tripod ligands in solution. Under these
conditions the polymer changed its color to the colors
characteristic of these types of tripod-complexes. The
covalent fixation of these chromophoric groups was
probed by trying to extract the colored tripod-metal
complexes with THF or methylene chloride. Even over
a period of days no colored compounds were extracted
into these solvents, and the color of the polymer re-
mained unchanged.
3. Experimental
3.1. General
All manipulations were carried out under an argon
atmosphere by means of standard Schlenk techniques.
All solvents were dried by standard methods and des-
tilled under argon. The CDCl3, CD2Cl2 and [D8]THF
used for the NMR spectroscopic measurements were
degassed by three successive ‘freeze-pump-thaw’ cycles
˚
and dried over 4-A molecular sieves. The silica gel
(Kieselgel z.A. 0.06–0.2 mm, J.T. Baker Chemicals
B.V.) used for chromatography was degassed at 1 mbar
for 24 h and saturated with argon. NMR: Bruker
Avance DPX 200 at 200.13 MHz (1H), 50.323 MHz
(13C{1H}), 81.015 MHz (31P{1H}); chemical shifts (l)
with respect to CDCl3 (1H: l=7.27, 13C: l=77.0),
CD2Cl2 (1H: l=5.32, 13C: l=53.5) and [D8]THF (1H:
l=3.58, 13C: l=67.7) as internal standards, and with
respect to 85% H3PO4 (31P: l=0) as external standard.
IR: Bruker FT-IR IFS-66; CaF2 cells. MS: Finnigan
MAT 8400; FAB: Nibeol (4-nitrobenzyl alcohol) or
TEA (triethanol amine) matrices, respectively; EI: 70
eV. Elemental analyses: microanalytical laboratory of
the Organisch-Chemisches Institut, Universita¨t Heidel-
berg. Melting points: Gallenkamp MFB-595 010; melt-
ing points were not corrected. All other chemicals were
commercially obtained and used without further
purification.
3.2. Preparation of 1
Sodium-hydride (11.3 g; 470 mmol) was suspended in
THF (600 ml) at 0°C. The mixture was warmed to
room temperature and 4-methoxybenzyl-malonic-acid-
diethylester (120.0 g; 430 mmol), dissolved in THF (100
ml) was added dropwise. The mixture was stirred until
no more hydrogen evolved (2.5 h). Chloromethylben-
zylether (67 g; 430 mmol) dissolved in THF (50 ml) was
added and the mixture was refluxed for 3 h. The
turbid-white mixture was allowed to cool to 25°C and
was hydrolized with aqueous NH4Cl (5%) and ice. The
aqueous phase was extracted with diethylether (2×100
ml). The combined organic phases were washed with
water (100 ml) and dried (MgSO4). After removal of
the solvent 153 g crude product remained as a colorless
Taken together, these observations show that the
phenolate linker group as present in 12 is efficient in the
covalent fixation of tripod ligands on appropriately
functionalized polymers.
Scheme 7.

P. Schober et al. / Journal of Organometallic Chemistry 571 (1998) 279–288
285
Table 3
1H-NMR data of 3, 4a, 6, 7, 10, 11 and 12
a
RO
p-ArCH2C
CCH2X
X
Aromatic H
3, R=Me; X=OH 3.75, s, 3H
4a, R=Me; X=Cl 3.81, s, 3H
2.64, s, 2H
2.77, s, 2H
2.61, s, 2H
3.47, d, 6H, [4.9]
3.50, s, 6H
3.78, m, 6H
—
—
6.79–7.20, m, 4H
6.86–7.31, m, 4H
6.62–6.84, m, 4H
6, R=Me; X=
OSO2Ph
3.78, bs, 3H
7.5–7.9, m, 15H
7, R=Me; X=
PPh2
3.78, s, 3H
2.86, s, 2H
2.38, s, 6H
7.25–7.37, bm, 30H
6.76–7.10, m, 4H
10, R=H; X=Cl
11, R=Et; X=Cl
12, R=H; X=PPh2
5.03, s, 1H
1.44, t, 3H, [7.0] 4.03, m, 2H
—
2.77, s, 2H
2.78, s, 2H
2.83, s, 2H
3.48, s, 6H
3.48, s, 6H
2.35, s, 6H
—
—
6.79–7.26, m, 4H
6.89–7.26, m, 4H
7.90–7.34, m, 20H
7.24, bm, 30H
2
a In CDCl3 solution at 25°C; l values; JHH coupling constants in Hz.
Table 4
13C-NMR data of 3, 4a, 6, 7, 10, 11 and 12
a
RO
p-ArCH2C
CCH2X
X
C quart.
Aromatic C
3, R=Me; X=OH
4a, R=Me; X=Cl
6, R=Me; X=OSO2Ph
7, R=Me; X=PPh2
10, R=H; X=Cl
55.6, s
55.0, s
55.6, s
55.0, s
—
65.9, s
45.5, s
33.5, m
42.7, m
45.5, s
45.5, s
45.5, s
35.4, m, (8.8)
34.2, s, 6H
67.5, s
39.8, m, (7.7)
34.2, s
—
—
44.6, m
45.2, m
113–159, m
114–159, m
114–159, m
113–157, m
114–155, m
114—158, m
114–153, m
114–135, m
113–139, m
—
43.4, m
42.6, m
45.2, m
45.3, m
45.6, m
11, R=Et; X=Cl
12, R=H; X=PPh2
14.6, s; 63.2, s
—
34.3, m
38.8, m
—
114–139, m
1
a In CDCl3 solution at 25°C; l values; JCP couplings constants in Hz.
Table 5
Crystal data and structural analysis results for 5, 7, 8 and 9
Compound
5
7
8
9
Formula
C47H42OClP3
751.2
Triclinic
C48H45OP3
730.8
C54H54N3OP3B2F8Fe C51H45O4P3Mo
Molecular mass (g mol−1
Crystal system
Space group (no.)
a (pm)
)
1083
910.7
Monoclinic
P21/c (14)
1908.7 (3)
2039.9 (3)
1030.9 (3)
90.000 (0)
89.16 (1)
90.000 (0)
4013
Triclinic
Monoclinic
P21/c (14)
1007.0 (2)
2523.6 (4)
1848.8 (3)
90.000 (0)
102.51 (0)
90.000 (0)
4587
(
(
P1 (2)
P1 (2)
1053.7 (3)
1392.5 (3)
1474.5 (3)
104.24 (2)
104.89 (1)
96.92 (2)
1992
1454.7 (3)
1496.1 (3)
1587.6 (2)
115.66 (1)
114.76 (1)
72.45 (1)
2798
b (pm)
c (pm)
h (°)
i (°)
k (°)
Cell volume (106 pm3)
Molecular units/cell
2
4
2
4
Dcalc. (g cm−3
)
1.252
1.209
1.384
1.449
Temperature (K)
200
298
200
200
No. of reflections for cell parameter refinement
Scan range (°)
31
29
30
31
4.1B2qB46.0
14.0
5853
4.0B2qB46.0
10.0
5766
3.5B2qB49.0
12.0
9515
4.1B2qB48.0
10.0
7629
Scan speed (° min−1) ꢀ-scan
No. of reflections measured
No. of unique reflections
5502
5577
9101
7180
No. of reflections observed (I\2|)
No. of parameters refined
4535
477
0.29
3.8/11.2
2554
472
0.25
7.3/17.7
6780
779
0.65
5.2/15.8
4750
566
0.69
7.3/15.9
residual electron density (10−6 e pm−3
)
R1/Rw (%) (refinement on F2)
oil which was purified by column chromatography on
silica gel (20 cm, Ø=4 cm). The fraction eluted with a
mixture of petrol ether 40/60/diethylether (3:1, TLC
(CDCl3): l=1.25 (t, J=7.5 Hz, 6 H, CCH3), 3.36 (s,
2H, ArCH2), 3.72 (s, 2 H, CCH2OBzl), 3.77 (s, 3 H,
CH3O), 4.20 (q, J=7.5 Hz, 4 H, OCH2CH3), 6.79–7.35
(m, 9 H, H aromatic). C23H28O6 (400.2): Anal. Calc. C
1
control: Rf=0.50) gave 1 as a colorless oil. H-NMR

286
P. Schober et al. / Journal of Organometallic Chemistry 571 (1998) 279–288
68.98, H 7.05; found C 69.15, H 7.24. MS (EI); m/z
phases were filtered over 3 cm silica gel covered with 2
cm MgSO4. The filtrate was concentrated and the re-
sulting residue was chromatographed on silica gel (15
cm, Ø=4 cm). The fraction eluted by a mixture of
petrolether 40/60/diethylether (3:1, TLC control: Rf=
0.66) gave 13 g 4a as a colorless solid (m.p. 52°C) in a
67% yield. Traces of 4b were contained in the product
as was evidenced by mass spectroscopy (weak signal at
m/z 316). C12H15OCl3 (281.6): Anal. Calc. C 51.13, H
5.33; found C 51.15, H 5.44; MS(EI); m/z (%): 281 (11)
(%): 400 (4) [M+], 91 (100) [C7H7+].
3.3. Preparation of 2
LiAlH4 (30 g; 790 mmol) was suspended in di-
ethylether (400 ml) at 0°C. A solution of crude 1 (153 g;
380 mmol) in diethylether (200 ml) was added drop-
wise. After the addition the mixture was stirred at 40°C
for 4 h. The mixture was allowed to cool to 25°C and
hydrolized by slow addition of water (30 ml), 15%
aqueous NaOH (30 ml) and water (90 ml) subsequently.
It was separated by filtration from hydrolization prod-
ucts which were further extracted by a Soxhlet-appara-
tus with diethylether. The combined organic phases
were dried (MgSO4) and the solvent was removed in
vacuo. A total of 122 g of crude product remained as a
colorless oil which was purified by column chromatog-
raphy on silica gel (20 cm, Ø=4 cm). The fraction
eluted with diethylether (TLC control: Rf=0.54) gave 2
1
[M+], 121 (100) [C8H9O+]. (For H- and 13C-NMR
data see Tables 3 and 4).
3.6. Preparation of 5
When the reaction intended to give 4a was run at
70°C the product contained an appreciable amount of
4b. A solution of this product mixture (1.4 g) in DMSO
(5 ml) was added to
a solution of potassium-
diphenylphosphide (4.5 g; 20 mmol) in DMSO (34 ml)
and the mixture was refluxed for 3 h at 120°C. The
solvent was removed in vacuo and the sticky grey
residue was washed with 50 ml H2O by stirring 16 h.
The remnants were dissolved in diethylether and dried
with MgSO4. Removing the solvent in vacuo and wash-
ing five times with 20 ml of petrol ether 40/60 gave the
crude product as a viscous colorless oil or a sticky
colorless powder. Crystals suitable for X-ray analysis
were obtained by slowly evaporating a solution of 5 in
petrolether40/60/diethylether within several days. 1H-
NMR (CDCl3): l=2.4 (s, 6 H, CH2P), 2.86 (s, 2 H,
ArCH2), 6.8–7.4 (m, 33 H, H aromatic). 13C-NMR
(CDCl3): l=39.7 (m, CH2P), 43.3 (m, ArCH2), 45.2
(m, C quart), 128–150 (m, C aromatic). C47H42OClP3
(750.4): Anal. Calc. C 75.23, H 5.60; found C 74.92, H
5.53. MS(FAB); m/z (%): 750 (8) [M+], 673 (100); 585
(11). 31P{1H}-NMR (CDCl3): l= −28.8 (s).
1
as a colorless oil. H-NMR (CDCl3): l=2.69 (bs, 2 H,
CCH2O), 3.18 (m, 2 H, OH), 3.39 (s, 2 H, ArCH2), 3.68
(m, 4 H, CH2OH), 3.82 (s, 3 H, CH3O), 4.53 (s, 2 H,
OCH2Ar), 6.8-7.4 (m, 9 H, H aromatic). 13C-NMR
(CDCl3): l=35.4 (m, J=8.8 Hz, CH2P), 44.6 (m, C
quart.), 55.6 (s, CH3O), 65.9 (s, CH2), 113–158 (m, C
aromatic). C19H24O4 (316.4): Anal. Calc. C 72.13, H
7.65; found C 71.91, H 7.73. MS(EI); m/z (%): 316 (10)
[M+], 121 (100) [C8H9+].
3.4. Preparation of 3
Crude 2 (23.4 g; 77.4 mmol) and 4 g of Pd/C (10%)
were suspended in ethanol (350 ml). The mixture was
kept under an atmosphere of hydrogen and stirred for
2 days at 20°C. The progress of the reaction was
monitored by TLC. The mixture was filtered over silica-
gel and the solvent was removed in vacuo. A total of
16.4 g crude product was obtained as a viscous oil
which was purified by column chromatography on sil-
ica gel (20 cm, Ø=4 cm). The fraction eluted with
diethylether (TLC control: Rf=0.19) gave 3 as a highly
viscous colorless oil. C12H18O4 (226.3): Anal. calc. C
63.71, H 7.96; found C 63.29, H 8.91. MS(EI); m/z (%):
3.7. Preparation of 6
A solution of 3 (10.0 g; 43 mmol) in 60 ml pyridine
was cooled to 8°C. Benzenesulfonylchloride (27.3 g; 155
mmol) was added by a funnel. The mixture was stirred
for 1 day and poured into a mixture of 100 ml water,
200 ml methanol and 80 ml concentrated HCl. A
viscous oil separated, which solidified after several days.
Recrystallisation from ethanol (50 ml) gave 22.8 g of 6
as a white powder (m.p. 105°C) in 80% yield.
C30H30O10S3 (646.8): Anal. Calc. C 55.71, H 4.68;
found C 55.62, H 4.63. MS(EI); m/z (%): 646 (22)
1
226 (10) [M+], 121 (100) [C8H9+]. (For H- and 13C-
NMR data see Tables 3 and 4).
3.5. Preparation of 4a
A solution of 3 (10.0 g; 44 mmol) in 11 ml pyridine
was cooled to 0°C. Thionylchloride (18 g; 150 mmol)
was added slowly by a syringe. The temperature of the
mixture was kept below 10°C. After addition the mix-
ture was refluxed for 3 h, allowed to cool to 25°C,
hydrolized by water (8 ml) and extracted with
dichloromethane (3×20 ml). The combined organic
1
[M+], 121 (100) [C8H9O+]. (For H- and 13C-NMR
data see Tables 3 and 4).
3.8. Preparation of 7
A solution of diphenylphosphane (7.8 g; 42 mmol) in

P. Schober et al. / Journal of Organometallic Chemistry 571 (1998) 279–288
287
40 ml dimethylsulfoxide was deprotonated with KOtBu
in an ice bath. After stirring for 1 h 6, (8 g; 12.4 mmol)
diluted in 15 ml dimethylsulfoxide, was added and the
mixture was refluxed for 3 h. After removing the sol-
vent in vacuo the procedure of washing and drying
followed the recipe for 5. Further purification was
performed by column chromatography on silica gel (20
cm, Ø=4 cm). The fraction eluted with a mixture of
petrol ether 40/60/diethylether (10:1, TLC control:
Rf=0.25) gave 5.6 g 7 as a white solid (m.p. 141°C) in
63% yield. C48H45OP3 (730): Anal. Calc. C 78.90, H
6.16; found C 78.50, H 6.38; MS(FAB); m/z (%): 730
(32) [M+], 653 (100) [M+-Ph]. 31P{1H}-NMR
Anal. Calc. C 67.26, H 4.98; found C 64.88, H 4.94.
(with the analytical equipment used, carbon values tend
to be found too low in the presence of boron or
molybdenum); MS(FAB); m/z (%): 912 (18) [M+], 825
(12) [M+ –3CO], 307 (100). 31P{1H}-NMR (CD2Cl2):
l=16.1 (s). IR (CH2Cl2): w(CO)=1932 cm−1 (s), 1832
cm−1 (s).
3.11. Preparation of 10
4a (10 g; 35 mmol) was mixed with (CH3)3SiI (12.5 g;
50 mmol) at room temperature and stirred for 5 days
under an inert atmosphere and was hydrolized with
methanol/hydrochloric acid (10 ml). The mixture was
stirred for 1 day. Volatile constituents were removed in
vacuo, the brown residue was dissolved in methylene
chloride. Filtering over silica gel gave a colorless solu-
tion which after removing the solvent in vacuo left 10
as a colorless solid. Further purification was performed
by column chromatography on silica gel (20 cm, Ø=4
cm). The fraction eluted with a mixture of petrol ether
40/60/diethylether (3:1, TLC control: Rf=0.30) gave
9.5 g 10 as a colorless solid (m.p. 68°C) in quantitative
yield. C11H13O3Cl3 (267.6): Anal. Calc. C, 49.37; H,
4.86; found C, 48.87; H, 4.87. MS(EI); m/z (%): 266
(19) [M+]; 107 (100) [C7H7O+]. (For 1H- and 13C-
NMR data see Tables 3 and 4).
1
(CD2Cl2): l= −28.1 (s). (For H-and 13C-NMR data
see Tables 3 and 4).
3.9. Preparation of 8
[Fe(CH3CN)6](BF4)2 (357 mg; 0.75 mmol) was added
to a solution of 7 (548 mg; 0.75 mmol) in acetonitrile
(30 ml). The color of the mixture immediately turned
red. After stirring for 1 h at room temperature the
solvent was removed in vacuo. The red residue was
washed several times with diethylether. After drying in
vacuo 856 mg of 8 were obtained as a red powder in
96% yield. Crystals suitable for X-ray analysis were
obtained by diffusion of diethylether into a solution of
1
8 in CH2Cl2 within 2 days. H-NMR (CDCl3): l=2.37
(bs, 9 H, CH3CN), 2.73 (bs, 6 H, CH2P), 3.3 (bs, 2 H,
ArCH2), 4.0 (bs, 3 H, CH3O), 7.2–7.4 (m, 34 H, H
aromatic). 13C-NMR (CDCl3): l=37.7 (m, CH2P),
3.12. Preparation of 11
10 (230 mg; 0.86 mmol) was dissolved in THF (20
ml) and deprotonated with KOtBu (100 mg; 0.89 mmol)
at 0°C. Iodoethane (536 mg; 3.61 mmol) was added and
the mixture was warmed to room temperature. The
turbid mixture was stirred for 1 h, the solvent was
removed and the residue dissolved in CH2Cl2 (5 ml).
The solution was filtered over silicagel and dried in
vacuo. Further purification was performed by column
chromatography on silica gel (20 cm, Ø=4 cm). The
fraction eluted with a mixture of petrol ether 40/60/di-
ethylether (3:1, TLC control: Rf=0.73) gave 233 mg 11
as a colorless oil in 92% yield. C13H17OCl3 (295.7):
Anal. Calc. C 52.82, H 5.80; found C 52.31, H 5.71.
MS(FAB); m/z (%): 294 (40) [M+], 135 (100)
[C9H11O+], 107 (96) [C7H7O+]. (For 1H- and 13C-
NMR data see Tables 3 and 4).
42.6 (m,
C quart), 126–155 (m, C aromatic).
C54H54N3OP3FeB2F8 (1083): Anal Calc. C 59.87, H
5.02, N 3.88; found C 56.54, H 5.18, N 4.33. (with the
analytical equipment used, carbon values tend to be
found too low in the presence of boron); MS(FAB);
m/z (%): 1041 (6) [M+ –MeCN], 731 (100). 31P{1H}-
NMR (CD2Cl2): l=29.43 (s). IR (KBr): w(CN)=2324
cm−1 (w), 2288 cm-1 (m).
3.10. Preparation of 9
(CH3CN)3Mo(CO)3 (144 mg; 0.47 mmol) was added
to a solution of 7 (316 mg; 0.43 mmol) in CH2Cl2 (70
ml). After stirring for 16 h at room temperature, 15 ml
petrol ether 40/60 was added to the mixture. The
mixture was filtered over 2 cm silica gel and the solvent
was removed in vacuo. A total of 385 mg of 9 was
obtained as a pale yellow powder in 98% yield. Crystals
suitable for X-ray analysis were obtained by diffusion
of diethylether into a solution of 9 in CH2Cl2 within
several days. 1H-NMR (CDCl3): l=2.32 (s, 6 H,
CH2P), 2.86 (s, 2 H, ArCH2), 3.78 (s, 3 H, CH3O),
6.7–7.4 (m, 34 H, H aromatic). 13C-NMR (CDCl3):
l=37.5 (m, CH2P), 41.2 (m, C quart), 53.4 (s, CH3O),
111–157 (m, C aromatic). C51H45O4P3Mo (910.7):
3.13. Preparation of 12
To
a
solution
formed
by
deprotonating
diphenylphosphane (23 g; 123 mmol) in 30 ml DMSO
by KOtBu (13.8 g; 123 mmol) at 0°C a solution of 10
(11 g; 41.2 mmol) was added in one portion and the
mixture was refluxed for 3 h at 120°C. After removing
the solvent in vacuo the procedure of washing and
drying followed the recipe for 5. Further purification

288
P. Schober et al. / Journal of Organometallic Chemistry 571 (1998) 279–288
M. Di Vaira, M. Peruzzini, P. Stoppioni, J. Chem. Soc. Dalton
Trans. (1984) 359. (d) M. Di Vaira, P. Innocenti, S. Moneti, M.
Peruzzini, P. Stoppioni, Inorg. Chim. Acta (1984) 83. (e) P.
Barbaro, C. Bianchini, C. Mealli, A. Meli, J. Am. Chem. Soc.
113 (1991) 3181. (f) A. Barth, G. Huttner, M. Fritz, L. Zsolnai,
Angew. Chem. 102 (1990) 956; Angew. Chem. Int. Ed. Engl. 29
(1990) 929. (g) S. Vogel, A. Barth, G. Huttner, T. Klein, L.
Zsolnai, C. Emmerich, Angew. Chem. 103 (1991) 325; Angew.
Chem. Int. Ed. Engl. 30 (1991) 303. (h) S. Vogel, G. Huttner, L.
Zsolnai, Z. Naturforsch. 48b (1993) 641. (i) C. Mealli, Acta
Crystallogr. B38 (1982) 1040.
was performed by column chromatography on silica gel
(20 cm, Ø=4 cm). The fraction eluted with a mixture
of petrol ether 40/60/diethylether (1:1, TLC control:
Rf=0.40) gave 18.9 g 12 as a white solid (m.p. 140°C)
in 64% yield. C47H43OP3 (716.8): Anal. Calc. C 78.76,
H 6.05; found C 77.73, H 6.46. MS(EI); m/z (%): 716
(12) [M+], 639 (100) [M+ –Ph]. 31P{1H}-NMR
1
(CD2Cl2): l= −28.8 (s). (For H- and 13C-NMR data
see Tables 3 and 4).
[2] (a) A. Muth, A. Asam, G. Huttner, A. Barth, L. Zsolnai, Chem.
Ber. 127 (1994) 305. (b) B. Janssen, V. Sernau, G. Huttner, A.
Asam, O. Walter, M. Bu¨chner, L. Zsolnai, Chem. Ber. 128
(1995) 63. (c) A. Asam, B. Janssen, G. Huttner, L. Zsolnai, O.
Walter, Z. Naturforsch. 48b (1993) 1707. (d) A. Asam, B.
Janssen, G. Huttner, L. Zsolnai, Chem. Ber. 127 (1994) 501. (e)
H. Heidel, J. Scherer, A. Asam, G. Huttner, O. Walter, L.
Zsolnai, Chem. Ber. 128 (1995) 293. (f) Th. Seitz, A. Asam, G.
Huttner, O. Walter, l. Zsolnai, Z. Naturforsch. 50b (1995) 1287.
(g) O. Walter, Th. Klein, G. Huttner, L. Zsolnai, J. Organomet.
Chem. 458 (1993) 63. (h) Th. Seitz, A. Muth, G. Huttner, Th.
Klein, O. Walter, M. Fritz, L. Zsolnai, J. Organomet. Chem. 469
(1994) 155. (i) A. Jacobi, G. Huttner, U. Winterhalter, Chem.
Ber. 130 (1997) 1279. (j) C. Bianchini, P. Frediani, V. Sernau,
Organometallics 14 (1995) 5458.
[3] P. Schober, R. Soltek, G. Huttner, L. Zsolnai, K. Heinze, Chem.
Ber. (submitted).
[4] K. Rorig, J.D. Johnston, Org. Synth. IV4 (1963) 576.
[5] D.S. Connor, G.W. Klein, G.N. Taylor, R.K. Boeckman Jr.,
J.B. Medwig, Org. Synth. Coll. VI, 101.
[6] S. Beyreuther, J. Hunger, G. Huttner, S. Mann, L. Zsolnai,
Chem. Ber. 129 (1996) 745.
[7] B.J. Hathaway, D.G. Holah, A.E. Underhill, J. Chem. Soc.
(1962) 244.
3.14. X-ray structure determinations
The measurements for 5, 7, 8, 9 were carried out on
a Siemens P4 Diffractometer with graphite-monochro-
mated Mo–Kh radiation. The intensities of three check
reflections (measured every 100 reflections) remained
constant throughout the data collections, thus indicat-
ing crystal and electronic stability. All calculations were
performed using the SHELXT PLUS software package.
Structures were solved by direct methods with the
SHELXS-86 ([12]a) program and refined with the
SHELX93 program ([12]b). Graphical handling of the
data was done using XPMA [13]. Absorption correc-
tions („ scan, D„=10°) were applied to the data. The
structures were refined in fully anisotropic models by a
full-matrix least-squares calculation. Hydrogen atoms
were introduced at calculated positions.
Further details of the crystal structure investigations
may be obtained from the Fachinformationszentrum
Karlsruhe, D-76344 Eggenstein-Leopoldshafen (Ger-
many), on quoting the depository numbers CSD-
408094 for 5, CSD-407838 for 7, CSD-407837 for 8,
and CSD-407836 for 9 (Table 5).
[8] D.P. Tate, W.R. Knipple, J.M. Augl, Inorg. Chem. 1 (1962) 433.
[9] P. Schober, Dissertation, Universita¨t Heidelberg, 1997.
[10] When PVA, after deprotonation with sodium in NH3(l), was
treated with the corresponding chlorine functionalized tripod no
reaction was observed.
[11] P. Schneider, in: Houben-Weyl (Ed.), Methoden der organischen
Chemie, Band XIV/2, Thieme Verlag, Stuttgart, 1963.
[12] (a) G.M. Sheldrick, Universita¨t Go¨ttingen, 1986. (b) G.M.
Sheldrick, Universita¨t Go¨ttingen, 1993. (c) International Tables
for X–ray Crystallography, Bd. 4, Kynoch Press, Birmingham,
1974.
References
[1] (a) M. Di Vaira, L. Sacconi, Angew. Chem. 94 (1982) 338;
Angew. Chem. Int. Ed. Engl. 21 (1982) 330. (b) M. Di Vaira, S.
Middolini, L. Sacconi, J. Am. Chem. Soc. 101 (1979) 1757. (c)
[13] XPMA, L. Zsolnai, G. Huttner, Heidelberg, 1994.
.
.