Preparation and catalytic application of MCM-41 modified with a ferrocene carboxyphosphine and a ruthenium complex

Article abstract of DOI:10.1016/j.molcata.2004.07.032

MCM-41 molecular sieves modified with Hdpf and/or, [{Ru(η⁶- p-cymene)Cl(μ-Cl)}₂] and the molecular compound 2 were used as catalysts for the reaction between propargyl alcohol and benzoic acid to give 2-oxopropyl benzoate. Reaction of 1′-(diphenylphosphino) ferrocenecarboxylic acid (Hdpf) with mesoporous molecular sieve MCM-41 gives immobilized carboxyphosphine (3), which was further reacted with [{Ru(η⁶-p-cymene)Cl(μ-Cl)}₂] (1) to afford Ru/carboxyphosphine-modified molecular sieve 4. A simple reaction between MCM-41 and 1 afforded Ru-only modified molecular sieve 5. Materials 4 and 5 were tested as catalysts for the reaction of propargyl alcohol with benzoic acid to give 2-oxopropyl benzoate (6). The reactions catalyzed with immobilized catalysts are slower and give lower yields of the ester as compared to the homogeneous precatalyst [Ru(η⁶-p-cymene)(Hdpf-κP)Cl ₂] (2), which was prepared from Hdpf and the dimer 1. Formation of ester 6 catalyzed with 4 and 5 competes with a parallel, propargyl alcohol consuming process, which occurs also with MCM-41 itself in the absence of benzoic acid and ruthenium compounds. The solid-state structure of 2·CH₂Cl₂ has been determined by single-crystal X-ray diffraction.

Full text of DOI:10.1016/j.molcata.2004.07.032

Journal of Molecular Catalysis A: Chemical 224 (2004) 161–169
Preparation and catalytic application of MCM-41 modified with a
ferrocene carboxyphosphine and a ruthenium complexଝ
a,∗
a,b
b
ˇ
ˇ
ˇ
ˇ
ˇ´
Petr Stepnicka , Jan Demel , Jirı Cejka
a
Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-128 40 Prague 2, Czech Republic
b
J. Heyrovsky´ Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejsˇkova 3, CZ-182 23 Prague 8, Czech Republic
Received 16 March 2004; received in revised form 27 July 2004; accepted 30 July 2004
Dedicated to Professor Jozef J. Ziołkowski on the occassison of his 70th birthday.
Abstract
Reaction of 1ꢀ-(diphenylphosphino)ferrocenecarboxylic acid (Hdpf) with mesoporous molecular sieve MCM-41 gives immobilized car-
boxyphosphine (3), which was further reacted with [{Ru(␩6-p-cymene)Cl(␮-Cl)}2] (1) to afford Ru/carboxyphosphine-modified molecular
sieve 4. A simple reaction between MCM-41 and 1 afforded Ru-only modified molecular sieve 5.
Materials 4 and 5 were tested as catalysts for the reaction of propargyl alcohol with benzoic acid to give 2-oxopropyl benzoate (6). The
reactions catalyzed with immobilized catalysts are slower and give lower yields of the ester as compared to the homogeneous precatalyst
[Ru(␩6-p-cymene)(Hdpf-␬P)Cl2] (2), which was prepared from Hdpf and the dimer 1. Formation of ester 6 catalyzed with 4 and 5 competes
with a parallel, propargyl alcohol consuming process, which occurs also with MCM-41 itself in the absence of benzoic acid and ruthenium
compounds. The solid-state structure of 2·CH2Cl2 has been determined by single-crystal X-ray diffraction.
© 2004 Elsevier B.V. All rights reserved.
Keywords: Ferrocene carboxyphosphine; MCM-41; Ruthenium; Immobilization; 2-Oxopropyl benzoate; X-ray crystallography
1. Introduction
ane, linker with a solid matrix, typically silica [2]. Another,
apparently more suitable solid supports worth testing for im-
mobilization of homogeneous organometallic catalysts are
mesoporous molecular sieves.
Catalytic systems involving ferrocene ligands proved of-
ten superior to analogous systems with classical organic lig-
ands. As a result, ferrocene ligands have found widespread
practical applications even at the industry scale [1]. Since
immobilized catalytic systems are usually more chemically
robust, easier separable and recyclable (etc.) than their ho-
mogeneous counterparts and thus attractive from economical
and ecological viewpoints, attempts have been made to attach
ferrocene ligands to solid supports. Anchoring of ferrocene
compounds has been achieved by reacting a ferrocene ligand
or its complex modified with a suitable, mostly amidosilox-
A new era in the investigation of mesoporous molec-
ular sieves started with the successful synthesis of these
materials at Mobil Research and Development Corporation
in early 1990s [3]. Mesoporous molecular sieves are pre-
pared by using template strategy with supramolecular sur-
factant assemblies (e.g., long-chain alkyl amines, carboxylic
acids or triblock copolymers) to form inorganic building
blocks with the required geometry [4,5]. They exhibit uni-
form pores of hexagonal or cubic ordering with pore dimen-
sions ranging from 2.0 to about 30 nm, surface areas often
larger than 1000 m2/g, amorphous walls and long-range or-
dering [6]. The large surface areas and narrow pore size dis-
tribution as compared to conventional materials [7] make the
utility of molecular sieves as a support for organometallic
ଝ
Presented at the 14th International Conference on Homogeneous Catal-
ysis in Munich, Germany. For a reference, see Books of Abstracts, p. 206.
∗
Corresponding author.
ˇ
E-mail address: stepnic@natur.cuni.cz (P. Steˇpnicˇka).
1381-1169/$ – see front matter © 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.molcata.2004.07.032

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162
spectra; 2JPC = 4.3 and 5.9 Hz). The 31P NMR coordination
shift of 2 (∆P = 36.9, ∆P = δP,complex − δP,free ligand) is very
similar to its analogue with ␩6-hexamethylbenzene ligand
[13], whereas the δP value itself is slightly down-field from
the reference compound, due to a lowered electron density at
the metal centre and, hence, at the phosphorus atom, resulting
from the presence of a less electron donating arene ligand.
The matrix mass spectra of 2 exhibit fragment ions corre-
spondingtothelossofoneortwochlorideligands([M–nCl]+,
n = 1, 2), fragments resulting from an elimination of the car-
boxycyclopentadienyl ring and iron atom, [M–C6H5O2Fe]+,
and ions due to phosphine cation (Hdpf+).
Scheme 1. Preparation of the molecular catalyst 2.
catalysis particularly attractive. This has been recently evi-
denced by a number of examples including immobilization of
an osmium-tertiary diolate complex for cis-dihydroxylation
of double bonds [8], anchoring [{Rh(␩2:␩2-cycloocta-1,5-
diene)(␮-OCH3)}2] complex on MCM-41 and its conversion
to an immobilized hydride complex, which was highly active
in polymerization of phenylethyne and its ring-substituted
derivatives [9], and also by immobilization of chiral ferrocene
catalysts [10].
Considering the abovementioned properties and applica-
tions of mesoporous molecular sieves, we decided to study
a system based on carboxy-functionalized ferrocenylphos-
phine, 1ꢀ-(diphenylphosphino)ferrocenecarboxylic acid
(Hdpf) [11], and MCM-41, where the conformationally
flexible 1,1ꢀ-disubstituted ferrocene unit may act as a spacer
between the anchoring (carboxyl) and catalytic (phosphine)
sites. In this contribution, we describe the preparation
and characterization of MCM-41 sieves modified with
[{Ru(␩6-p-cymene)Cl(␮-Cl)}2] and Hdpf. We also report
on the activity of the Ru-modified materials as catalysts
in ruthenium-catalyzed reaction between benzoic acid
and propargylalcohol to synthetically valuable 2-oxopropyl
benzoate [12]—in a comparison with a molecular precatalyst
[Ru(␩6-p-cymene)(Hdpf-␬P)Cl2].
2.2. The solid-state structure of 2
Recrystallization of 2 from dichloromethane-hexane af-
forded the solvate 2·CH2Cl2, which was characterized by
single-crystal X-ray diffraction analysis. The compound
crystallizes with two crystallographically independent but
structurally nearly identical molecules within the unit cell
(A and B). A view of the molecular structure of molecule
A is shown in Fig. 1 and the selected geometric param-
eters for both crystallographically independent molecules
are listed in Table 1. The overall molecular geometry
is rather unexceptional when compared to the related
arene–ruthenium complexes with ferrocene phosphines such
as: [{␮-1␬P:2␬Pꢀ-Fe(␩5-C5H4CH2PPh2)2}{RuCl2(␩6-C6
H2Me4-1,2,3,4)}2] [14], and [Ru{=C(CH2Fc)OMe}(␩6-
C6Me6)Cl(Hdpf-␬P)]·CH2Cl2 (Fc = ferrocenyl) [13].
The molecules of 2 associate into dimers involving both
independent molecules via double hydrogen bridges between
their peripheral carboxy groups, A· · ·B (Table 2). This ar-
rangement is frequently encountered in complexes where
Hdpf coordinates as a simple phosphine [15] as well as in
Hdpf itself [11]. The dimers are linked further by weak hy-
drogen bonds to solvating dichloromethane (Table 2). Hy-
drogen bonding is apparently the major force towards in-
termolecular association in 2·CH2Cl2 since neither signifi-
cant ␲· · ·␲ stacking interactions between sterically encum-
bered ␲-rings nor C–H· · ·␲-ring interactions were detected
in the structure [the strongest C–H· · ·␲-ring contacts are in-
2. Results and discussion
2.1. Preparation and characterization of the molecular
catalysts
˚
tramolecular: C(41)–H(41)· · ·Ph1: C(41)· · ·Cg43.785(4) A,
C(41)–H(41)· · ·Cg4168◦; C(82)–H(82C)· · ·Ph5: C(82)· · ·
Complex [Ru(␩6-p-cymene)(Hdpf-␬P)Cl2] (2) was syn-
thesized in nearly quantitative yield by cleavage of the
chloro bridges in dimeric ruthenium(II) complex [{Ru(␩6-p-
cymene)Cl(␮-Cl)}2] (1) with stoichiometric amount of Hdpf
(Scheme 1). The identity and purity of the complex were con-
firmed by NMR, IR, mass spectrometry, elementary analysis
◦
˚
Cg93.562(5) A, C(82)–H(82C)· · ·Cg9158 ; for the definition
of the symbols see Table 1].
2.3. Preparation and characterization of supported
materials
1
and by single-crystal X-ray diffraction. H and 13C NMR
spectra of 2 are in full accordance with the proposed three-
legged piano stool structure [(␩6-arene)RuCl2(phosphine-
␬P)]. This is mainly manifested by a significantly up-field
shifted carbon and hydrogen resonances due to the arene CH
groups(␦C 85–91, ␦H 5.10–5.20)andtheircouplingswithRu-
bonded phosphorus atom (arene CH resonances in 13C NMR
Hdpf-modified MCM-41 (3) was prepared by adding
Hdpf solution in toluene to carefully dried molecular sieve
(2 mmol/10 g), shaking the resulting suspension for 24 h and,
finally, Soxhlet extraction of the solid with dichloromethane
to remove unreacted Hdpf. Mass balance (the amount of
recovered Hdpf) and elemental analysis showed that 84%

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P. Steˇpnicˇka et al. / Journal of Molecular Catalysis A: Chemical 224 (2004) 161–169
163
Fig. 1. A view of the molecule A in the structure of 2·CH2Cl2 showing the thermal motion ellipsoids scaled to 30% probability and atom labelling scheme.
of the carboxyphosphine remained adsorbed on the sup-
port, which corresponds to ca. 0.16 mmol of Hdpf per 1 g
of the resulting material. A subsequent reaction of 3 with 1
in dichloromethane and similar workup gave Ru/phosphine
modified sieve (4). Catalytic results (see below), prompted us
to synthesize also MCM-41 modified only with 1. The Ru-
only modified molecular sieve (5) was obtained easily and
with complete retention of the ruthenium complex by adding
1 dissolved in dichloromethane to solid MCM-41.
ular sieve with Hdpf (to give 3) and further with 1 (to give 4)
decreased the surface areas and void volume of the formed
composite materials. In addition, a slight decrease in the pore
diameter from 3.5 nm to about 3.0 nm was observed after
modification of MCM-41 molecular sieve (cf. Table 3).
IR spectra of 3 and 4 in the carbonyl stretching region
(Fig. 4) showed a dominant band at 1630 cm−1 and an unre-
solved, less intense band at ca. 1700 cm−1. The position of
the bands is very similar to those in 2 (1702 and 1674 cm−1
The modified sieves 3–5 were characterized by X-ray flu-
orescence analysis, powder X-ray diffraction, IR and solid-
stateNMRspectra, andtexturalmeasurements. X-raydiffrac-
tion patterns observed for the parent calcinated mesoporous
MCM-41 and the modified materials (Fig. 2) exhibited five
clearly discernible reflections with 2θ < 10◦, indicating a reg-
ular hexagonal ordering of all these mesoporous molecular
sieves. The X-ray diffraction patterns of 5 (see Section 4)
were identical to MCM-41 and the modified sieves 3 and
4, thus corroborating unaffected structure of the support. The
textural parameters of calcined MCM-41, 3 and 4 were deter-
mined by nitrogen adsorption isotherms recorded at −196 ◦C
(Fig. 3). The adsorption isotherm of calcined MCM-41 evi-
denced the typically well-ordered structure of the sieve with
the characteristic steep increase in the adsorbed amount at
the relative pressure p/p0 ca. 0.3. Modification of the molec-
Fig. 2. Powder X-ray diffraction patterns for MCM-41 (A), 3 (B), 4 (C).

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164
Table 1
◦
˚
Selected geometric parameters for 2·CH2Cl2 (in A and )
Molecule A
Molecule B
Ru(1)–Cg1
Ru(1)–Cl(1)
Ru(1)–Cl(2)
Ru(1)–P(1)
Fe(1)–Cg2
Fe(1)–Cg3
P(1)–C(11)
P(1)–C(22)
1.702(1)
Ru(5)–Cg6
Ru(5)–Cl(5)
Ru(5)–Cl(6)
Ru(5)–P(5)
Fe(5)–Cg7
Fe(5)–Cg8
P(5)–C(51)
P(5)–C(62)
1.705(1)
2.4037(8)
2.4221(7)
2.3692(7)
1.660(1)
1.655(1)
1.823(3)
1.827(3)
1.831(3)
1.323(3)
1.228(3)
1.458(4)
89.99(2)
87.81(2)
85.25(2)
122.76(4)
126.16(4)
131.78(5)
179.15(6)
122.8(2)
101.4(1)
105.0(1)
103.3(1)
76.5(1)
2.4012(7)
2.4263(7)
2.3665(7)
1.658(1)
1.654(1)
1.826(3)
1.827(3)
1.833(3)
1.318(3)
1.228(3)
1.463(4)
89.24(2)
87.44(2)
85.96(2)
124.07(4)
126.27(4)
130.63(4)
179.11(6)
123.1(2)
101.2(1)
104.8(1)
103.9(1)
75.0(1)
P(1)–C(28)
O(1)–C(21)
O(2)–C(21)
P(5)–C(68)
O(5)–C(61)
O(6)–C(61)
C(16)–C(21)
Cl(1)–Ru(1)–Cl(2)
Cl(1)–Ru(1)–P(1)
Cl(2)–Ru(1)–P(1)
Cg1–Ru(1)–Cl(1)
Cg1–Ru(1)–Cl(2)
Cg1–Ru(1)–P(1)
Cg2–Fe(1)–Cg3
O(1)–C(21)–O(2)
C(11)–P(1)–C(22)
C(11)–P(1)–C(28)
C(22)–P(1)–C(28)
ꢁAr1, Cp1
C(56)–C(61)
Cl(5)–Ru(5)–Cl(6)
Cl(5)–Ru(5)–P(5)
Cl(6)–Ru(5)–P(5)
Cg6–Ru(5)–Cl(5)
Cg6–Ru(5)–Cl(6)
Cg6–Ru(5)–P(5)
Cg7–Fe(5)–Cg8
O(5)–C(61)–O(6)
C(51)–P(5)–C(62)
C(51)–P(5)–C(68)
C(62)–P(5)–C(68)
ꢁAr5, Cp5
ꢁAr1, Ph1
39.4(1)
26.3(1)
59.0(1)
1.4(2)
ꢁAr5, Ph5
40.2(1)
29.3(1)
59.7(1)
1.3(2)
ꢁAr1, Ph2
ꢁAr5, Ph6
ꢁPh1, Ph2
ꢁPh5, Ph6
ꢁCp1, Cp2
ꢁCp5, Cp6
Atom in both molecules are numbered analogously; atom labels in molecule 2 are obtained by adding four to the first digit in the respective atom label in
molecule 1. Definitions, ring plane: plane atoms (centroid): molecule A, Ar1: C(34–39) (Cg1), Cp1: C(11–15) (Cg2), Cp2: C(16–20) (Cg3), Ph1: C(22–27)
(Cg4), Ph2: C(28–33) (Cg5); molecule B, Ar5: C(74–79) (Cg6), Cp5: C(51–55) (Cg7), Cp6: C(56–60) (Cg8), Ph5: C(62–67) (Cg9), Ph6: C(68–73) (Cg10).
in KBr; cf. 1666 cm−1 for Hdpf in Nujol [11]) and signif-
Table 2
◦
˚
Hydrogen bond parameters for 2·CH2Cl2 (in A and )
D–H· · ·A D–H D· · ·A
icantly higher than the values observed for the related car-
boxylate salts (Nadpf: 1540 [11]; M(dpf)2, where M = Ca,
Sr and Ba: 1535–1547 cm−1 [16]) and carboxylate complex
[(␩5-C5HMe4)2Ti(dpf-␬2O,Oꢀ)] (1506 cm−1 [17]). IR spec-
trum of 5 in the same region (1300–1800 cm−1) showed weak
D–H· · ·A
O(1)–H(1)· · ·O(6) and (x − 1, y − 1, z) 0.82(4) 2.654(3) 177(5)
O(5)–H(5)· · ·O(2) and (1 + x, 1 + y, z)
C(91)–H(91A)· · ·O(2)
0.83(4) 2.654(3) 178(4)
0.97
0.97
0.97
0.97
3.175(4) 148
3.158(4) 145
3.657(3) 153
3.707(3) 153
C(92)–H(92B)· · ·O(6)
C(91)–H(91B)· · ·Cl(2)
C(92)–H(92A)· · ·Cl(6)
Values involving hydrogen atoms in calculated positions are given with-
out standard uncertainties. Labelling of the solvating dichloromethane:
C(91)H(91A)H(91B)Cl(91)Cl(92) and C(92)H(92A)H(92B)Cl(93)Cl(94).
D = donor, A = acceptor.
to medium-intensity bands (see Section 4) attributable to the
organometallic modifier. The region of ␯ vibrations in IR
OH
spectra of all compound is dominated by a very broad band
at ca. 3750 cm−1
.
Table 3
Textural properties of parent MCM-41 and the modified sieves 3 and 4
Sample (m2 g−1
)
SBET (cm3 g−1
)
Vmeso (nm)
d (nm)
MCM-41
3
4
1085
843
795
0.914
0.590
0.541
3.5
3.2
3.0
Fig. 3. Nitrogen adsorption isotherms of parent MCM-41 (A), 3 (B), and 4
(C). For clarity, isotherms B and C are onset by 5 and 10 mmol g−1, respec-
tively.

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165
Fig. 4. IR spectra of 3 (A) and 4 (B).
In 31P CP MAS NMR spectra, the phosphorus containing
sieves 3 and 4 showed resonances with quite similar chemical
shifts, δP 33 and 35, respectively, which are both markedly
down-field compared to the signal of uncoordinated Hdpf in
CDCl3 solution (δP −17.6 [11]), closer to values typical for
P-coordinated Hdpf or the corresponding phosphine oxide
(HdpfO; δP 32.9 in CDCl3 [11]).
species), which can also account for the catalyst leaching
(see below).
Although one can expect the immobilized catalysts to ex-
hibit an activity lower than the analogous homogeneous sys-
tem, the low efficiency observed for the precatalysts 4 and 5
results also from the inherent properties of the sieve: MCM-
41 behaves as a non-innocent support, promoting a parallel
process, which is faster than the formation of 6 and con-
verts propargyl alcohol to an unidentified, probably poly-
meric side product. This can be demonstrated by a much
steeper decrease in the propargyl alcohol content in the re-
action mixture containing catalyst 4 when compared to cat-
alyst 2 (see Figs. 5–7). This side reaction occurs in a similar
2.4. Catalytic experiments
The testing reaction between benzoic acid and propar-
gyl alcohol to give 2-oxopropyl benzoate (6) (Scheme 2)
was performed in toluene with 0.5 mol% ruthenium pre-
cursor added either as a defined molecular compound (2)
or in the supported form (4 and 5). In all cases, the reac-
tion proceeded with the formation of the expected product
6, however it was much faster with the molecular catalyst
(Fig. 5). With the molecular catalyst 2 and 1.5-fold molar
excess of propargyl alcohol with respect to the acid, about
84% of the acid was converted to 6 within 24 h at 80 ◦C
(Fig. 6) while the supported catalysts 4 and 5 under other-
wise identical conditions produced 6 in yields lower than
20% (Fig. 7; 19% yield of 6 has been achieved with catalyst
4 after 68 h). In all cases, the ester starts to form after an
induction period, which is significantly longer for the sup-
ported catalysts (see Figs. 5–7). This points to a necessary
activation of the catalyst (formation of an catalytically active
Fig. 5. A comparison of the rate of ester 6 formation with catalyst 2 (ꢀ),
heterogenised catalyst 4 (᭹), and phosphine-free heterogenised catalyst 5
(ꢂ).
Scheme 2.

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166
Fig. 8. A comparison of product formation in the mixture containing het-
erogenised catalyst 5 (᭹) and in the same system where the solid catalyst
was removed after heating for 4 h (ꢂ, the removal time is indicated by an
arrow).
Fig. 6. Kinetic profile for the testing reaction with homogenous catalyst 2
(᭹, propargyl alcohol; ꢀ, benzoic acid; ꢂ, ester 6).
extent also when a solution of the alcohol is heated only
with MCM-41 in toluene without addition of benzoic acid
and a ruthenium compound. Attempts to improve the se-
lectivity of the reaction by lowering the reaction temper-
ature failed, the yields of 6 being even lower (ca. 0.4%
at 40 ◦C and ca. 3.7% at 60 ◦C with the same educt ratio
after 68 h).
ruthenium species after cooling the reaction mixture to room
temperature.
3. Conclusions
When the immobilized catalysts 4 and 5 were removed
after heating of the reaction mixture for 4 h (by centrifu-
gation and filtration of the supernatant through a 0.45 ␮m
PTFE syringe filter), the reaction did not stop but slowed
down significantly (Fig. 8). This indicates some leaching
of the active form of the catalyst during the reaction. No-
tably, when the catalyst was recovered from the cold reaction
mixture after the experiment, washed well with toluene and
reused at the same ratio (i.e., 5 mol% as calculated from the
original Ru content), it showed activity as high as the orig-
inal sample of the immobilized catalyst. The preserved cat-
alyst activity can be accounted for a re-adsorption of active
The reaction of MCM-41 with Hdpf and 1 in a stepwise
manner produced 4 while the direct treatment of the sieve
with 1 gave Ru-only modified MCM-41, 5. The spectral data
did not allow us to draw clear conclusion about the nature of
the interaction of the sieve with modifiers but indicated for
3 and 4 that Hdpf and 1 are anchored independently rather
than in a form analogous to the molecular compound 2. Con-
sidering the results of textural measurements (i.e., stepwise
lowering of the surface area, the void volume and a decrease
of the pore diameter) may indicate a simple sorption of the
modifying agents in the pores and on the surface. This pro-
cess is probably accompanied by an irreversible change at
the phosphino moiety of Hdpf, which prevents it to ligate
ruthenium.
In the reaction between propargyl alcohol and benzoic
acid to give 2-oxopropyl benzoate, the supported materials
are less active and selective than homogeneous precatalyst
2, producing yet unknown, probably polymeric side product
from propargyl alcohol, the latter property being inherent to
the support (MCM-41). However, the presented results in-
dicate that the metal-modifiers remain tightly bound to the
support and, although some leaching occurs during catalyzed
reaction, the supported materials can be reused at least once
without a loss of their original activity. In addition, it is ap-
parent that the preparation of supported catalyst may elim-
inate the need for the presence of stabilizing ligands, such
as phosphines (see Ref. [12]). Despite the bonding between
the modifiers and the solid support remains not fully under-
stood, the early attempt at anchoring of Hdpf and 1 opens
new possibilities in the immobilization of ferrocene ligands.
Fig. 7. Kinetic profile for the testing reaction with heterogenised catalyst 4
(᭹, propargyl alcohol; ꢀ, benzoic acid; ꢂ, ester 6).

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167
(d, J = 6.1 Hz, 2H) and 5.19 (d, J = 5.7 Hz, 2H) (AAꢀBBꢀ sys-
tem of C6H4), 7.42–7.50 (m, 6H, PPh2), 7.83–7.90 (m, 4H,
PPh2). 13C NMR (CDCl3): δ 17.1 (s, Me), 21.7 (s, CHMe2),
30.0 (s, CHMe2), 70.2 (s, Cipso of C5H4CO2H), 71.6 (s,
CH of C5H4CO2H), 73.0 (d, JPC = 8 Hz, CH of C5H4PPh2),
75.6 (s, CH of C5H4CO2H), 76.6 (d, JPC = 10 Hz, CH of
C5H4PPh2), 78.4 (d, 1JPC = 48 Hz, Cipso of C5H4PPh2), 86.0
4. Experimental
4.1. Materials and methods
All-siliceous MCM-41 was synthesized from sodium sil-
icate (Riedel de Haen), hexadecyltrimethylammonium bro-
mide (Fluka) and ethyl acetate (Fluka) at 100 ◦C for 50 h as
described in detail in Refs. [18,19]. The template was re-
moved by calcination in a stream of air at 550 ◦C for 6 h.
Prior to the modification reactions, the sieve was dried at
200 ◦C Torr for 2 h.
2
2
(d, JPC = 6 Hz, CH of C6H4), 90.3 (d, JPC = 4 Hz, CH
of C6H4), 94.5, 109.5 (2 × s, Cipso of C6H4); 127.8 (d,
JPC = 10 Hz, CH of PPh2), 130.4 (d, JPC = 2 Hz, CH of PPh2),
133.9 (d, JPC = 10 Hz, CH of PPh2), 136.3 (d, 1JPC = 47 Hz,
Cipso of PPh2), 177.0 (s, CO2H). 31P NMR (CDCl3): δ 19.3
Hdpf was prepared according to the literature procedure
[11]. Complex 1 (Strem) was used without further purifica-
tion. Dichloromethane was dried over potassium carbonate
while toluene was dried over potassium metal and distilled
under nitrogen. Syntheses of complex 2 and the supported
compounds 3–5 were performed under argon blanket and the
subsequent workup was carried out in air.
(s). IR (KBr, cm−1): ␯ 3054 (w), 2870 (w); ␯
1702
C O
CH
(s), 1674 (s); 1471 (s), 1434 (s), 1386 (m), 1290 (m), 1159
(m), 1096 (m), 1029 (s); 835 (m), 746 (s), 698 (s); 540–469
(s, composite). Anal. calcd. for C33H33Cl2FeO2PRu: C,
55.02; H, 4.62%. Found: C, 55.41; H, 4.79%. HR LSIMS:
[C33H3335Cl256FeO2P102Ru]+ (M+), calcd. 719.9994, found
719.9992; [C33H3335Cl56FeO2P102Ru]+ ([M–Cl]+), calcd.
685.0308, found 685.0300. LSIMS, m/z (relative intensity):
722 (2, M+), 685 (23, [M–Cl]+), 649 (82, [M–2Cl]+), 611
(11, [M–C6H5O2]+), 485 (100, [M–C6H5O2–2Cl]+), 414
(67, Hdpf+).
1
Solution H (399.95 MHz), 31P{1H} (161.90 MHz), and
13C{1H} NMR (100.58 MHz) spectra were measured at
25 ◦C on a Varian UNITY Inova 400 spectrometer. Chemical
shifts (δ, ppm) are given relative to internal tetramethylsi-
lane (1H and 13C) and external 85% aqueous H3PO4 (31P).
31P{1H} solid-state NMR spectra were measured on a Var-
ian spectrometer (121.473 MHz) at room temperature us-
ing the CP/MAS technique (5 mm rotor, spinning 5–7 kHz,
contact time 1.5 ms) and solid (NH4)2HPO4 as the refer-
ence (δP 0). Positive-ion liquid secondary-ion mass spectra
(LSIMS) were obtained on a VG ZabSpec spectrometer in 3-
nitrobenzylalcohol matrix using CsI as the primary ion source
(Cs+) and poly(ethylene glycol) as the mass scale calibrant
for high-resolution (HR) measurements. IR spectra in KBr
4.3. Preparation of MCM-41-supported Hdpf (3)
A solution of Hdpf (0.8285 g, 2.00 mmol) in toluene
(200 ml) was added to MCM-41 (10.0 g). The mixture
was shaken on a mechanical shaker for 24 h at room
temperature. Then, the solid was separated by filtration,
washed with toluene and dichloromethane and extracted
with dichloromethane in a Soxhlet extractor for 8 h. A
subsequent drying in air at ambient temperature afforded
carboxyphosphine-modified MCM-41 (3) as a fine, brownish
solid. Yield: 10.5 g.
The extract was evaporated under vacuum, leaving a rusty
brown residue, which was analyzed as Hdpf by NMR spec-
troscopy (0.1354 g, 16% recovery). X-ray fluorescence anal-
ysis for 3: P, 0.49; Fe, 0.87%. Calculated from mass balance
(84% retention of Hdpf): P, 0.48; Fe, 0.87%. IR (KBr, cm−1):
1690, 1630, 1475, 1440, 1390, 752, 727, 704, 695. 31P CP-
MAS NMR: δP 33.0.
´ ´
pellets were recorded on an FT IR Nicolet Protege 460 spec-
trometer. X-ray powder diffractograms were recorded using a
Siemens D5005 instrument operating in the Bragg-Brentano
˚
geometry arrangement using Cu K␣ radiation (λ = 1.5412 A).
Nitrogen adsorption isotherms were measured at −196 ◦C
on an ASAP 2010 (Micromeritics) equipped with a 133 kPa
transducer. All samples were evacuated before measure-
ment at 150 ◦C for at least 24 h. X-ray fluorescence analy-
sis was carried out with a Philips PW 1404 using Uniquant
analytical.
4.2. Preparation of
[{␩6-p-Me2CHC6H4Me)}RuCl2(Hdpf-␬P)] (2)
4.4. Modification of the supported phosphine with 1
Solid 1 (0.459 g, 0.75 mmol) and Hdpf (0.621 g,
1.50 mmol) were dissolved in dichloromethane (30 mL). Af-
ter stirring for 2 h, the solution was evaporated to dryness
and the solid washed well with diethyl ether (2 × 20 mL)
and dried under vacuum (0.2 Torr/50 ◦C/1 h) to afford 2 as
Modified sieve 3 (8.00 g) was added to a solution of 1
(0.3833 g, 0.6259 mmol) in dichloromethane (65 ml). The
mixture was stirred for 24 h at room temperature, the solid
filtered off and washed well with dichloromethane and dried
in air at room temperature to give Ru/P-modified MCM-41
(4). Yield: 8.0 g.
1
a rusty orange solid (1.052 g, 97%). H NMR (CDCl3): δ
0.93 (d, 3JHH = 6.9 Hz, 6H, CHMe2), 1.80 (s, 3H, Me), 2.52
The solvent and washings were evaporated, leaving only
5.3 mg of a brown material, containing mostly unreacted 1
3
(septet, JHH = 6.9 Hz, 1H, CHMe2), 3.91 (apparent t, 2H,
1
CH of C5H4CO2H), 4.40 (m, 4H, CH of C5H4PPh2 and
C5H4CO2H), 4.63 (apparent q, 2H, CH of C5H4PPh2), 5.14
according to H NMR spectra. X-ray fluorescence analysis
for 4: P, 0.50; Fe, 0.92; Ru, 0.35%. Calculated from mass

ˇ
168
P. Steˇpnicˇka et al. / Journal of Molecular Catalysis A: Chemical 224 (2004) 161–169
Table 4
balance assuming that 99% of 1 reacted: P, 0.48; Fe, 0.87;
Ru, 1.54%. IR (KBr, cm−1): virtually identical to 3. 31P CP-
MAS NMR: δP 34.9.
Crystallographic data, data collection and structure refinement for 2·CH2Cl2
Formula
C34H35Cl4FeO2PRu
M (g mol−1
)
805.31
Crystal system
Space group
Triclinic
P-1 (no. 2)
12.3808(2)
12.7439(2)
20.8371(3)
91.3979(9)
95.508(1)
96.542(1)
3249.11(9)
4
1632
1.646
1.321a
58536
55.0
14695/10321
5.42
783
4.5. Preparation of Ru-modified MCM-41( 5)
˚
a (A)
A solution 1 (0.065 g, 0.11 mmol) in dichloromethane
(20 ml) was added to MCM-41 (1.568 g) and the mixture was
stirred for 22 h at room temperature. The solid was filtered
off, washed well with dichloromethane (4 × 15 ml), and dried
under vacuum. This procedure afforded Ru-modified molec-
ular sieve 5 quantitatively and, as revealed by the analysis of
the washing, with quantitative retention of Ru on the support
(ca. 0.13 mmol Ru/g of the solid).
X-ray fluorescence analysis for 5: Ru 0.09%. Calculated
from mass balance (complete retention of 1 assumed): Ru
0.13%. IR (KBr, cm−1): 1745 (w), 1637 (m), 1461 (w), 1401
(w), 1384 (w). Powder X-ray diffraction: 2θ (◦) 2.25 (s), 3.78
(m), 4.45 (m) and 5.92 (vw).
˚
b (A)
˚
c (A)
α (◦)
β (◦)
γ (◦)
3
˚
V (A )
Z
F(000)
Dc (g cm−3
)
µ(Mo K␣) (mm−1
)
Collected diffractions
2θmax (◦)
Unique/observedb diffractions
Rint (%)c
Number of parameters
R observed diffractions (%)d
R, wR al−l 3data (%)d
˚
3.65
6.44, 8.72
1.30, − 0.87e
4.6. Catalytic experiments
ꢀρ (e A
)
a
Corrected for absorption (Gaussian correction based on the crystal
shape), transmission coefficient range: 0.584–0.922.
Catalytic experiments were carried out in a three-necked
flask (50 ml) immersed in a thermostated oil bath ( 2◦) and
equipped with a magnetic stirring bar, thermometer, reflux
condenser and a rubber septum. All experiments were per-
formed under nitrogen.
b
Diffractions with I0 > 2(I0).
Σ|F02 − ꢁF02ꢃ|
c
Rint
=
.
Σ|F02|
ꢀ
ꢁ1/2
Σw(F02 − Fc2)24
Σw(F02)2
ΣꢄF0| − |Fcꢄ
d
e
A reaction mixture consisting of propargyl alcohol
(0.89 ml, 0.15 mmol), benzoic acid (0.122 g, 10 mmol),
mesitylene (internal standard; 0.28 ml, 2.0 mmol) and dry
toluene (10 ml) was thoroughly mixed at preset reaction
temperature. Then, the amount of a catalyst correspond-
ing to 0.05 mmol (0.5 mol%) ruthenium was added. Reac-
tion samples were periodically withdrawn by a syringe for
at least 48 h (24 h for homogeneous catalyst 2) and an-
alyzed by a high-resolution gas chromatography (Agilent
6850 equipped with flame ionization detector and DB-5
capillary column). All reaction products were checked by
GC-MS (Hewlett-Packard 5890 Series II, 5971A). A sam-
ple of pure ester 7 was obtained by chromatography of the
reaction mixture (silica gel, hexane-ether). Analytical data
for 6: NMR (CDCl3): δH 2.24 (s, 3H, Me), 4.88 (s, 2H,
CH2), 7.43–8.13 (m, 5H, Ph); δC 26.23 (Me), 68.75 (CH2),
128.52 (CH of Ph), 129.20 (Cipso of Ph), 129.91 (CH of Ph),
133.48 (CH of Ph), 165.87 (COO), 201.83 (C(O)Me); MS:
m/z (relative abundance) 178 (M+, 8), 163 ([M–CH3]+, 10),
148 ([M–CH2CO]+, 20), 135 ([M–CH2COCH3]+, 15), 122
([PhCO2H]+, 2), 105 ([PhCO]+, 100), 91 ([C7H7]+, 5) 77
(Ph+, 60), 51 ([C4H3]+, 35); HR MS: C10H10O3 (M+), calcd.
178.0630, found 178.0641.
R =
, wR =
.
Σ|F0
See Section 3.7 for the discussion of the high residual electron density.
0.63 mm × 0.63 mm) was mounted on a glass fibre by epoxy
cement and transferred to diffractometer. Full-set diffraction
data ( h
k l) were collected on a Nonius KappaCCD
diffractometer equipped with Cryostream Cooler (Oxford
Cryosystems) at 150(2) K using graphite monochromatized
Mo K␣ radiation (λ = 0.71073 A) and analyzed with HKL
˚
program package by Nonius BV (Table 4).
Cell parameters were determined by least-squares anal-
ysis from 40,700 partial diffractions with 1.0 ≤ θ ≤ 27.5◦.
The structure was solved by direct methods (SIR97 [20])
and refined by weighted full-matrix least-squares procedure
on F2 (SHELXL97 [21]). All non-hydrogen atoms were re-
fined with anisotropic thermal motion parameters. The hy-
drogen atoms were included in calculated positions [C–H
˚
˚
˚
bond lengths: 0.96 A (methyl), 0.97 A (methylene), 0.98 A
(methine), and 0.93 A (aromatic)] and assigned 1.5 Ueq(C)
˚
(methyl) and 1.2 Ueq(C) (all other). Isopropyl substituents at
the Ru-coordinated arene ring exhibit a disorder, most likely
due to an unhindered rotation along the pivotal C–C bond and,
hence, thespaceoccupiedbythesesubstituentsaccommodate
the largest residual electron density. Attempted refinement of
the isopropyl group over two or more positions failed. Final
geometric calculations were performed with a recent version
of Platon program [22].
4.7. X-ray crystallography
Recrystallization of 2 from dichloromethane-hexane
afforded red, plate-like single-crystals of solvato-
morph 2·CH2Cl2. The selected specimen (0.20 mm ×

ˇ
P. Steˇpnicˇka et al. / Journal of Molecular Catalysis A: Chemical 224 (2004) 161–169
169
Crystallographic data excluding the structure factors have
been deposited with the Cambridge Crystallographic Data
Centre [deposition no. CCDC-231990]. Copies of the data
can be obtaineduponrequest to CCDC, 12 Union Road, Cam-
bridge CB21EZ, UK; http://www.ccdc.cam.ac.uk, e-mail:
deposit@ccdc.cam.ac.uk.
[8] A. Severeyns, D.E. De Vos, L. Fiermans, F. Verpoort, P.J. Grobet,
P.A. Jacobs, Angew. Chem. Int. Ed. 40 (2001) 586.
[9] H. Balcar, J. Sedla´cˇek, J. Cejka, J. Vohl´ıdal, Macromol. Rapid Com-
ˇ
mun. 23 (2002) 32.
[10] (a) B.F.G. Johnson, S.A. Raynor, D.S. Shepherd, T. Mashmeyer, J.M.
Thomas, G. Sankar, S. Bromley, R. Oldroyd, L. Gladden, L. Mantle,
Chem. Commun. (1999) 1167;
(b) S.A. Raynor, J.M. Thomas, R. Raja, B.F.G. Johnson, R.G. Bell,
M.D. Mantle, Chem. Commun. (2000) 1925;
(c) T.J. Colacot, Chem. Rev. 103 (2003) 3101.
[11] J. Podlaha, P. Steˇpnicˇka, I. C´ısaˇrova´, J. Ludv´ık, Organometallics 15
Acknowledgements
ˇ
(1996) 543.
´ ˇ
´
The authors thank Dr. Ivana Cısarova for collecting X-ray
[12] (a) D. Devanne, C. Ruppin, P.H. Dixneuf, J. Org. Chem. 53 (1988)
926;
ˇ
diffraction data, Dr. Arnost Zukal for recording nitrogen ad-
sorption isotherms and Ing. Marcela Tkadlecova for record-
ing solid-state NMR spectra. This work was supported by the
Grant Agency of the Czech Republic (grant nos. 104/02/0571
and 203/99/M037) and is a part of a long-term Research Plan
of the Faculty of Sciences, Charles University.
(b) C. Bruneau, Z. Kabouche, M. Neveux, B. Seiller, P.H. Dixneuf,
Inorg. Chim. Acta 222 (1994) 155;
´
(c) C. Bruneau, P.H. Dixneuf, Chem. Commun. (1997) 507 (a re-
view).
ˇ
[13] P. Steˇpnicˇka, R. Gyepes, O. Lavastre, P.H. Dixneuf, Organometallics
16 (1997) 5089.
[14] J.F. Mai, Y. Yamamoto, J. Organomet. Chem. 560 (1998) 223.
ˇ
[15] (a) P. Steˇpnicˇka, R. Gyepes, J. Podlaha, Collect. Czech. Chem. Com-
mun. 63 (1998) 64;
(b) P. Steˇpnicˇka, J. Podlaha, R. Gyepes, M. Pola´sˇek, Organomet. J.
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