Reaction of Cp*RuCl(PPh3)2 with dioxygen and formation of a neutral complex Cp*RuCl(O2)(PPh3)

Article abstract of DOI:10.1016/S0022-328X(02)01978-2

Reaction of Cp*RuCl(PPh₃)₂ (1) with atmospheric oxygen occurs at room temperature in the presence of acetone or methylene chloride leading to Cp*RuCl(O₂)(PPh₃) (2). This complex is remarkably stable in the solid

Full text of DOI:10.1016/S0022-328X(02)01978-2

Journal of Organometallic Chemistry 663 (2002) 127Á133
/
www.elsevier.com/locate/jorganchem
Reaction of Cp*RuCl(PPh3)2 with dioxygen and formation of a
neutral complex Cp*RuCl(O2)(PPh3)
J. Roma´n Torres-Lubia´n 1, M. Esther Sa´nchez-Castro, Patricia Jua´rez-Saavedra,
Javier Herna´ndez-Mart´ınez 2, Ba´rbara Gordillo-Roma´n, M. Angeles Paz-Sandoval *
´ ´ ´
Departamento de Quımica, Centro de Investigacion y Estudios Avanzados del IPN, Av. Instituto Poltecnico Nacional 2508, Apdo. Postal 14-740, Mexico
D.F. 07300, Mexico
Received 24 May 2002; accepted 25 September 2002
This paper is dedicated to Professor Pascual Royo with our best wishes for his 65th birthday
Abstract
Reaction of Cp*RuCl(PPh3)2 (1) with atmospheric oxygen occurs at room temperature in the presence of acetone or methylene
chloride leading to Cp*RuCl(O2)(PPh3) (2). This complex is remarkably stable in the solid state and it can also release, under not
unduly harsh conditions, the activated oxygen molecule, which can oxidize the phosphite LꢀMeOP[(OCHMe)2CH2] to the
/
corresponding phosphate, along with formation of the mono- and disubstituted Cp*RuCl(PPh3)(L) (5), Cp*RuCl(L)2 (6) and
[Cp*RuCl(PPh3)(L)2]Cl (7), complexes. Structural information of phosphite derivatives 5 and 6 has been obtained by X-ray
diffraction.
# 2002 Elsevier Science B.V. All rights reserved.
Keywords: Dioxygen; Ruthenium neutral complexes; Cp*RuCl(PPh3)2
1. Introduction
The formation of analogue complexes with bidentate
ligands, such as the coordinatively unsaturated species
[Cp*Ru(PÃ
/
P)]ꢁ afforded, in the presence of oxygen,
During studies directed towards the replacement of
one triphenylphosphine in Cp*RuCl(PPh3)2 (1) [1], we
have made some interesting observations regarding the
facile oxidation of compound 1 with atmospheric
oxygen. Surprisingly, there has not been reports in the
literature about how easily it goes to the corresponding
oxidized compound Cp*RuCl(O2)(PPh3) (2).
complexes of the type [Cp*Ru(O2)(L-L)]ꢁ (L-Lꢀ
/dppe
[3,4], dppm [4], dippe [5] or Me2NCH2CH2NMe2 [6].
These oxygenated cationic complexes can be easily
formed, and everything indicates that the dioxygen
binding is irreversible.
A few examples containing a neutral dioxygen com-
The substitution of one or two triphenylphosphines in
compound 1 has been carried out with a variety of
ligands, where both, the effect on their corresponding
steric strain and electron density have been analyzed [2].
plex have been published: Cp*Ru(PPh3)(CÅ
/
CR)(O2),
including the dioxygen molecule as a ligand, has been
briefly mentioned by Bruce in the preparation of chiral
ruthenium acetylides, by removal of the chlorine atom
from Cp*Ru(CCHR)Cl(PPh3) in a methanolic solution
and adding excess of NaOMe [7]; the neutral peroxo
compound Cp*Ru(O2)[h3-CH2C(Me)CHC(Me)O] (3)
[8], without PPh3 as a ligand, and the synthesis and
structural characterization of RuCl(NO)(O2)(PPh3)2 [9]
and [Ru(H)(O2)(dippe)2]ꢁ [10] in which the ligand Cp*
is not present. Finally, the isoelectronic rhodium com-
plex Cp*Rh(PPh3)(O2) has been observed at low tem-
perature [11].
* Corresponding author. Tel.: ꢁ
/
52-5-7473717; fax: ꢁ52-5-7477113
/
E-mail address: mpaz@mail.cinvestav.mx (M. Angeles Paz-
Sandoval).
1
Present address: Departamento de Qu´ımica de Pol´ımeros, Centro
de Investigacio´n en Qu´ımica Aplicada, Blvd. Enrique Reyna 140,
Saltillo 25100 Coahuila, Mexico.
2
Present address: Centro de Investigacio´n en Alimentos
y
Desarrollo, A.C., Apdo. Postal 1735, Hermosillo 83000 Sonora,
Mexico.
0022-328X/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
PII: S 0 0 2 2 - 3 2 8 X ( 0 2 ) 0 1 9 7 8 - 2

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/
It has been reported that the (Cp*RuCl2)n complex
31P-NMR spectrum [dꢀ
39.7 (s)] of the reaction mixture
/
reacts rapidly, in less than 5 min, with O2 in air in
CHCl3 solution to give (Cp*RuCl2)2O and the molecu-
lar structure of the oxo complex was obtained, pre-
viously stabilized by dibenzothiophene [12]. Preliminary
reactivity studies show that (Cp*RuCl2)2O reacts with
showed that the only product of the reaction is 2.
Similar results were obtained when pure oxygen gas,
instead of air, was used. Compound 2 was also produced
when chloroform or methylene chloride solutions of 1
were exposed to air. However, 2 decomposes faster in
these solvents (4 h). The yields of 2 from the oxidation
reactions appear to be solvent dependent.
excess PPh3 to give Ph3PÄ
/
O, Cp*RuCl(PPh3)2, and
other unidentified metal complexes. We now know, that
one of those unidentified species is compound 2. The CÃ
/
Several attempts to get suitable crystals from acetone,
chloroform and methylene chloride solutions failed due
to the low stability of 2 in solution, recovering in some
cases crystals of 1, as a result of partial dissociation of
O2 and PPh3 from decomposition of compound 2,
suggesting the presence of the m-oxo complex (Cp*Ru-
Cl2)2O [13] in the reaction mixture.
H cleavage in (Cp*RuCl2)n leads to the h6-tetramethyl-
fulvene complex [(h6-C5Me4CH2)RuCl2]2 (4); the m-oxo
complex (Cp*RuCl2)2O is an intermediate, which spon-
taneously transforms into 4 with loss of water [13].
Also, activation of the Cp* ligand to give the aldehyde
[h5-C5Me4CHO]Ru[h5-CH2C(Me)CHC(Me)O]
had
been previously observed after heating compound 3
[8], which supports that oxygen-promoted cleavage of a
CH to take place. The same behavior, described by
Maitlis, occurs with conspicuous facility in Cp*RuIII
complexes [13]. In the electrochemical study of the
formation of compound 3, the proposed mechanism is
initiated by a fast one-electron transfer reaction, allow-
ing the oxidation of a RuII into a RuIII complex [14],
which is a reactive intermediate between the formation
of RuIV from RuII [14,15].
Compound 2 is presumably formed by displacement
of PPh3 in 1 with O2, as indicated by monitoring the
reaction with 31P-NMR spectroscopy.
A plausible mechanism for the formation of 2 is
shown in Scheme 1, which involves a 16 eꢂ intermediate
formed and oxygen completing the 18 eꢂ complex 2.
Subsequent activation of CÃ
/
H in the Cp* by the
coordinated rutheniumÁdioxygen complex 2, as pre-
/
viously described for a neutral peroxo compound
Cp*Ru(O2)[h3-CH2C(Me)CHC(Me)O] (3) [8], gives a
fulvene 4, which in the case of compound 3 continues
reacting until it produces the aldehyde compound [h5-
C5(Me4)CHO]Ru[h5-CH2C(Me)CHC(Me)O] [8]. The
1H-NMR of 4, product of the reactivity of compound
2 in solution, is quite complex [16], as previously
described by Maitlis for the mixture of tetramethylful-
venes in [(C5Me4CH2)RuCl2]2 (4) [13].
The reactivity of compound 2 in front of a cyclic
phosphite Lꢀ(MeO)P[(OCHMe)2CH2], was explored,
/
giving evidence of an easy release of O2 and formation
of mono- and disubstituted products Cp*RuCl(PPh3)(L)
(5), Cp*RuCl(L)2 (6) and [Cp*Ru(PPh3)(L)2]Cl (7),
along with the corresponding cyclic phosphate (MeO)O-
P[(OCHMe)2CH2].
As already mentioned, compound 2 is much more
stable in acetone, than in chloroform, methylene chlo-
ride, or benzene (partially soluble). However, in all
solvents, if compound 2 remains in solution sometime
(vide supra), the final products are OPPh3 and the
fulvene derivative 4, except in presence of the phosphite
ligand MeOP[(OCHMe)2CH2]. Interestingly, when 2 is
in CDCl3, in the presence of one equivalent of the
phosphite ligand, there is no evidence of decomposition
of compound 2, even after 24 h. Once the phosphite is
consumed giving the monosubstituted compound
Cp*RuCl(PPh3)[MeOP(OCHMe)2CH2] (5) and the dis-
ubstituted phosphite compounds Cp*RuCl[MeO-
P(OCHMe)2CH2]2 (6) and {Cp*RuCl(PPh3)[MeOP-
(OCHMe)2CH2]2}Cl (7), there is clear evidence of quick
consumption of compound 2, giving OPPh3 and the
isomers of fulvene complex 4.
2. Results and discussion
Exposure of acetone solutions of Cp*RuCl(PPh3)2 (1)
to air produced a brown solution from which the
dioxygen neutral monosubstituted chiral complex
Cp*RuCl(O2)(PPh3) (2) was isolated (Scheme 1). The
Replacement of the dioxygen ligand in compound 2
occurred under phosphite Lꢀ(MeO)P[(OCHMe)2CH2]
/
(mixture of cis- and trans-axial isomers in a ratio 95:5,
respectively) addition, in 1:2 and 1:5 ratios, respectively,
to give the chiral and prochiral compounds Cp*RuCl-
(PPh3)(L) (5), Cp*RuCl(L)2 (6) and [Cp*RuCl(PPh3)-
(L)2]ꢁ (7) (Scheme 2). The half-sandwich compounds 5
Scheme 1.

´
´
J. Roman Torres-Lubian et al. / Journal of Organometallic Chemistry 663 (2002) 127Á
/133
129
Scheme 2.
and 6 were obtained as yellow crystalline solids in 18
ppm): dꢀ152.5 (s)], along with evidence of oxidation of
/
and 73% yield, respectively. Compound 5 was obtained
in low yield, due to the formation of the disubstituted
phosphite compounds 6 and 7 (vide infra), even when
the synthesis was carried out with less than two
equivalents of L. Compound 5 can be separated from
6 and 7, by column chromatography and by solubility,
respectively. Structures of 5, 6 and 7 have been
some phosphite ligands. Also, formation of 7 competes
in the reaction mixture, and this product can be isolated
preferentially if, at least, a 1:3 ratio of 2Áphosphite is
/
used. Finally, it was observed that replacement of
dioxygen ligand in 2 for CO gave the well-known
Cp*RuCl(PPh3)(CO) [1b] and Cp*RuCl(CO)2 com-
plexes [17].
1
established by H-, 13C-, 31P-NMR, mass spectrometry
and those of 5 and 6 by single-crystal X-ray diffraction
studies. The crystal data are described in Table 1.
Compounds 5 and 6 have a piano-stool structure that
contains h5-pentamethylcyclopentadienyl ring, a chlor-
ine ligand and the phosphine and phosphite or two
phosphites, respectively, bonded to ruthenium through
phosphorus. An ORTEP representation is shown in Figs.
1 and 2. Atom positional parameters are given in Tables
2 and 3.
Table 1
Crystal data for compounds 5 and 6
5
6
Empirical formula
Molecular weight
Crystal system
Space group
C
698.14
34H43ClO3P2Ru C22H41ClO6P2Ru
600.01
Monoclinic
P21/n
Monoclinic
P21/c
As already observed from 7, the reaction also
promotes halide ionization and the eventual generation
of [Cp*Ru(PPh3)L2]Cl as deduced from 31P-NMR, d
˚
a (A)
12.0272 (10)
15.6258 (10)
17.5719 (10)
90.00
16.273 (3)
21.001 (4)
16.197 (3)
90.00
˚
b (A)
˚
c (A)
a (8)
b (8)
g (8)
(CDCl3)ꢀ149.5 (d, 15.3 Hz), 16.7 (t, 15.3 Hz). The
/
94.62 (2)
90.00
92.74 (3)
90.00
isolation of compound 7 as a strong yellow solid was
possible after exchanging the counterion Clꢂ for BF4ꢂ in
methylene chloride. The excess of phosphite is required
in order to get shorter reaction times, and it is
interesting to comment that only the cis-axial isomer
reacts. The easy formation of the phosphate MeOO-
3
˚
V (A )
Z
3291.6 (4)
4
5529.0 (18)
8
Crystal size (mm)
Absorption coefficient
(mmꢂ1
Dcalc (g cmꢂ3
Scan type
Data
0.22ꢃ0.17ꢃ0.15 0.32ꢃ0.16ꢃ0.16
0.687
0.812
)
)
1.409
v/2u
6882
6665
370
1.442
v/2u
10 106
9725
P[(OCHMe)2CH2] (31P d (CDCl3)ꢀ
31P-NMR through the corresponding oxidation of the
ax-cis-phosphite [31P (CDCl3, ppm): dꢀ
128.83 (ax-cis,
95%), 133.13 (ax-trans, 5%)], as well as formation of
compound 5 [31P (CDCl3, ppm): dꢀ
49.5 (d, 79.8), 151.5
/
ꢂ
/
5) is clear from
Unique data
Variables
/
579
6293
Observed data, F ꢀ4s(F)
Final R1
Final wR2
3369
0.0622
0.1428
/
0.0459
0.1283
(d, 79.2)]. If a larger excess of phosphite ligand is used,
formation of compound 6 is preferred [31P (CDCl3,

´
´
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J. Roman Torres-Lubian et al. / Journal of Organometallic Chemistry 663 (2002) 127Á133
/
Fig. 1. Molecular structure of Cp*RuCl(PPh3)[MeOP(OCHMe)2CH2] (5).
3. Conclusions
which in the presence of air yields compound 2. The
dioxygen ligand can be coordinated and uncoordinated
with relative facility, as already demonstrated by the
formation of chiral compounds 2 and 5. Complex 5 can
undergo a second substitution of the remaining bulky
triphenylphosphine ligand. The preference of the co-
The steric strain between the two bulky triphenylpho-
sphine ligands together with the high electron density
localized at the ruthenium center result in the ready
dissociation of one triphenylphosphine ligand from 1,
Fig. 2. Molecular structure of Cp*RuCl[MeOP(OCHMe)2CH2]2 (6).

´
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J. Roman Torres-Lubian et al. / Journal of Organometallic Chemistry 663 (2002) 127Á
/133
131
Table 2
ordination of the phosphite indicates that this ligand is
sterically less demanding and a better p ligand than the
triphenylphosphine.
˚
Selected bond lengths (A) and bond angles (8) for compound 5
Bond lengths
Conversion of 2 to the tetramethylfulvene derivative 4
and OPPh3 is achieved simply by dissolution of 2.
Further developments in the chemistry of 2 will be
based on its reactivity trends.
RuÃP1
RuÃP2
RuÃC1
RuÃC2
RuÃC3
RuÃC4
RuÃC5
C1ÃC2
C2ÃC3
C3ÃC4
C4ÃC5
C1ÃC6
2.205(2)
2.322(2)
2.287(7)
2.243(7)
2.235(8)
2.228(8)
2.264(8)
1.451(11)
1.457(12)
1.407(12)
1.444(12)
1.379(11)
RuÃCl
P1ÃO1
P1ÃO2
P1ÃO3
O1ÃC13
O2ÃC11
O3ÃC16
P2ÃC17
P2ÃC23
P2ÃC29
C5ÃC10
C19ÃC18
2.427(2)
1.604(6)
1.606(6)
1.623(6)
1447(10)
1.442(10)
1.430(11)
1.867(7)
1.825(8)
1.834(9)
1.517(12)
1.356(11)
4. Experimental
4.1. General procedures
Bond angles
P1ÃRuÃC4
P1ÃRuÃC3
C4ÃRuÃC3
P1ÃRuÃC2
C3ÃRuÃC2
C4ÃRuÃC2
P1ÃRuÃC5
C4ÃRuÃC5
C3ÃRuÃC5
C2ÃRuÃC5
P1ÃRuÃC1
P1ÃRuÃP2
All reactions were performed under a nitrogen atmo-
sphere, except those for compound 2, in reagent grade
solvents using Schlenk techniques. THF was distilled
115.6(3)
90.3(2)
36.8(3)
100.3(2)
38.0(3)
62.7(3)
151.3(2)
37.5(3)
61.5(3)
61.5(3)
136.6(2)
90.14(8)
C4ÃRuÃP2
C3ÃRuÃP2
C5ÃRuÃP2
C3ÃRuÃCl
C4ÃRuÃCl
P1ÃRuÃCl
P2ÃRuÃCl
C3ÃRuÃP2
C4ÃRuÃP2
C2ÃRuÃCl
C5ÃRuÃCl
O1ÃP1ÃRu
154.2(3)
152.0(2)
1117.1(2)
119.2(3)
87.4(2)
from NaÁbenzophenone, while acetone and CH2Cl2
/
1
were dry from CaSO4 and CaH2, respectively. The H-,
13C- and 31P-NMR spectra were recorded on JEOL
GSX-270, JEOL Eclipse-400 or Bruker 300 spectro-
meters using deuterated solvents and Me4Si and H3PO4
(85%) as internal and external references, respectively, in
CDCl3 at ambient temperature. Elemental analyses were
performed by Desert Analytics, Tucson, Arizona. Mass
spectra were measured on a Hewlett Packard HP-5990A
(EI, 70 eV), Finigan MAT 95 (FAB) and at the
Washington University (MALDI-MS). IR spectra were
100.41(9)
88.19(8)
152.0(2)
154.2(3)
148.9(2)
89.9(2)
114.3(2)
measured on a PerkinÁElmer/6FPC-FT spectrophot-
/
ometer using KBr. Melting points were recorded on
compounds in sealed nitrogen-filled capillaries and are
uncorrected.
Cp*RuCl(PPh3)2 [1e], axial-2-methoxi-4,6-dimethyl-
1,3,2-l3-dioxaphosphorinanes [18] were prepared by
literature methods.
Table 3
˚
Selected bond lengths (A) and bond angles (8) for compound 6
Bond lengths
Ru1AÃC2A
Ru1AÃC3A
Ru1AÃC1A
Ru1AÃP2A
Ru1AÃP1A
Ru1AÃC4A
Ru1AÃC5A
Ru1AÃCl1A
P2AÃO2A
P2AÃO1A
P2AÃO3A
P1AÃO4A
2.149(8)
2.172(7)
2.193(10)
2.206(2)
2.2146(15)
2.222(7)
2.234(10)
2.440(2)
1.584(4)
1.595(4)
1.618(4)
1.591(4)
RuÃC2
RuÃC1
RuÃC3
RuÃC4
RuÃC5
RuÃCl
2.199(6)
2.171(7)
2.234(6)
2.243(7)
2.263(7)
2.432(2)
1.603(4)
1.599(4)
1.584(4)
1.625(4)
1.601(4)
1.622(4)
4.2. Preparation of Cp*RuCl(O2)(PPh3) (2)
4.2.1. Chloro(dioxygen)(h5-pentamethylcyclopentadie-
nyl)(triphenylphosphine)ruthenium(IV)
P1ÃO1
P1ÃO2
P2ÃO4
P2ÃO6
P1AÃO5A
P1AÃO6A
a) A dry acetone solution (60 ml) containing 520 mg of
compound 1 (0.65 mmol) was bubbled with pure O2
during 45 min. The initial orangeÁ
/
yellow solution
turn brownÁorange and finally brown. The brown
/
Bond angles
C2AÃRu1AÃC3A
C2AÃRu1AÃC1A
C3AÃRu1AÃC1A
C2AÃRu1AÃP2A
C3AÃRu1AÃP2A
C1AÃRu1AÃP2A
C2AÃRu1AÃP1A
C3AÃRu1AÃP1A
C1AÃRu1AÃP1A
P2AÃRuÃP1A
38.3(5)
34.3(6)
59.6(4)
C1ÃRuÃC2
C1ÃRuÃP2
C1ÃRuÃP1
P1ÃRuÃP2
C2ÃRuÃP1
C1ÃRuÃC3
C2ÃRuÃC3
P1ÃRuÃC3
C2ÃRuÃC4
P1ÃRuÃC4
P2ÃRuÃCl
P1ÃRuÃCl
37.5(3)
109.6(3)
102.8(2)
90.05(6)
136.8(3)
61.9(3)
precipitate is filtered and the solid washed twice
with acetone and dry under vacuum. After reducing
the volume of the acetone solution, more brown
solid is obtained, giving 261 mg (0.46 mmol, 71%) of
95.8(3)
125.4(4)
101.4(5)
120.5(5)
94.0(2)
compound 2. M.p. 124Á
(CDCl3): d 1.34 (d, Jꢀ1.47 Hz, 15H, Cp*), 7.28Á
7.85 (m, 30H, PPh3). 31P-NMR: d 39.70 (s). 13C-
NMR: d 131.40 (d, Jꢀ9.9 Hz, o), 131.39 (s, p),
127.91 (d, Jꢀ12.1 Hz, m) 104.7 (s, Cp*), 7.91 (s,
Cp*), MS: 531 [Mꢂ Clꢂ
Cl]ꢁ(50), 515 [Mꢂ
O]ꢁ(100), 499 [Mꢂ O2]ꢁ (24). IR (CHCl3,
Clꢂ
/
125 8C, 1H-NMR
37.8(3)
157.42(2)
61.6(3)
/
/
152.9(5)
88.90(6)
102.7(2)
118.9(2)
/
121.6(3)
93.79(6)
93.57(6)
/
O1ÃP1ÃO2
O5ÃP2ÃRu
/
/
/
/
/

´
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J. Roman Torres-Lubian et al. / Journal of Organometallic Chemistry 663 (2002) 127Á133
/
cmꢂ1): 926. Anal. Found: C, 59.61; H, 5.28. Calc.
for C28H30ClO2PRu: C, 59.49; H, 5.31%.
b) A CH2Cl2 solution (15 ml) containing 200 mg of
compound 1 (0.25 mmol) was bubbled with air (20
ml syringe) and stirring during 60 min. The initial
tion mixture was stirred 1 h at r.t. and filtered. The light-
yellow solution was evaporated under vacuum and the
fraction soluble in Et2O was chromatographed under
silica with Et2OÁ
/
hexane (2/8) affording compounds 5
and 6. Recrystallization of 6 in C5H12 at r.t. gave 47 mg
1
orange solution turn brownÁ
volume of the CH2Cl2 solution, hexane is added and
brownÁred needles precipitate giving after filtra-
/red. After reducing the
(0.08 mmol, 71% yield). M.p. 116Á
(CDCl3): d 1.21 (dd, Jꢀ6.3, 4.6 Hz, Me4, Me6), 1.38
5.7 Hz, OMe),
/
119 8C, H-NMR
/
/
(m, 2H, H5), 1.65 (s, Cp*), 3.62, t, Jꢀ
/
tion, 100 mg (0.18 mmol, 71%) of compound 2.
4.52 (m, H4, H6). 31P-NMR: d 152.5 (s). 13C-NMR: d
9.5 (s, Cp*), 15.23 (s, C4a, C6a, Me), 65.8 (s, C4, C6,
CH), 41.9 (d, 3.8 Hz, C5, CH2), 51.83 (s, OMe), 92.73 (s,
4.3. Preparation of
Cp*RuCl(PPh3)[MeOP(OCHMe)2CH2] (5)
Cp*). MS: 600 [M]ꢁ(83), 436 [MꢂL2]ꢁ(100), 332 (52),
/
300 (13), 236 (63). Anal. Found: C, 44.39; H, 7.22. Calc.
for C22H41ClO6P2Ru: C, 44.03; H, 6.83%.
4.3.1. Chloro(2-methoxi-4,6-dimethyl-1,3,2-l3-
dioxaphosphorinane)(h5-pentamethylcyclopentadienyl)-
(triphenylphosphine)ruthenium(II)
4.5. Preparation of {Cp*Ru
(PPh3)[MeOP(OCHMe)2CH2]2]BF4 (7)
Compound 2 (143 mg, 0.25 mmol) in THF (20 ml)
gave a brown solution after addition, at room tempera-
ture (r.t.) of 0.1 ml (0.66 mmol) of the mixture of
phosphite isomers. After heating under reflux for 1 h,
the color of the solution changed from dark-brown to
bright-yellow. The bright-yellow solution was evapo-
rated under vacuum and the fraction soluble in Et2O
4.5.1. Bis(2-methoxi-4,6-dimethyl-1,3,2-l3-
dioxaphosphorinane)(h5-pentamethylcyclopentadienyl)-
(triphenylphosphine)ruthenium(II)tetrafloroborate
Compound 2 (180 mg, 0.32 mmol) in THF (20 ml)
gave a brown solution after addition, at r.t. of 0.16 ml
(1.1 mmol) of the mixture of phosphite isomers. After
heating under reflux for 15 min, the color of the solution
changed from dark-brown to bright-yellow. The yellow
solution was evaporated under vacuum and the fraction
soluble in Et2O was removed. The solid insoluble in
Et2O was dissolved in CHCl3 and hexane was added for
was chromatographed under silica with Et2OÁhexane
/
(2/8) affording two yellow bands. The first band gave
yellow needles of compound 5 (32 mg, 0.05 mmol, 18.3%
yield) after reducing volume and adding hexane and
maintaining this solution at ꢂ
fraction correspond to compound 6 which precipitates
from hexane at ꢂ15 8C in 3.3% yield (15.2 mg, 0.03
mmol). Compound 5: M.p. 169Á
172 8C, 1H-NMR
(CDCl3): d 0.53 (d, Jꢀ6.2 Hz, Me4), 1.20 (d, Jꢀ6.4
Hz, Me6), 1.56 (m, H5a,b), 1.34 (d, Jꢀ1.8 Hz, Cp*),
3.57 (d, Jꢀ11.3 Hz, OMe), 4.52 (m, H4) (4.22, m, H6),
7.56Á 79.8
7.68 (m, 30H, PPh3). 31P-NMR: d 49.5 (d, Jꢀ
Hz, PPh3), 151.5 (d, Jꢀ
79.2 Hz, phosphite). 13C-NMR:
d 21.54 (d, Jꢀ6.2 Hz, Me4), 22.47 (d, Jꢀ7.7 Hz, Me6),
70.1 (d, Jꢀ8.8 Hz, C4), 41.62 (s, C5), 68.7 (d, Jꢀ8.0
Hz, C6), 51.67 (s, OMe), 91.68 (s, Cp*), 9.58 (s, Cp*),
126.9 (d, Jꢀ8.5 Hz, Cm), 128.5 (s,Cp), 132.1 (d, Jꢀ9.2
Hz, Co), 135.0 (s,Ci). MS: 548 (2), 436 [Mꢂ
PPh3]ꢁ (7),
/
15 8C. The second
/
precipitation at ꢂ15 8C, affording an oily residue
/
/
which under vacuum gives a bright yellow powder, but
at r.t. remains as a oily solid 7-Cl in 38.3% (105 mg, 0.12
mmol). Compound 7-Cl (100 mg, 0.12 mmol) in CH2Cl2
(15 ml) gave a yellow solution after addition, at r.t. of
AgBF4 (22.6 mg, 0.12 mmol) in CH2Cl2 (2 ml).
Immediately a white precipitated of AgCl was observed.
After stirring for 5 min, the solid was filtered and the
solution evaporated until 5 ml, and adding hexane. The
filtration of the yellow precipitate gave 50 mg (0.05
/
/
/
/
/
/
/
/
/
/
/
/
/
mmol, 47.2% yield) of compound 7. M.p. 136Á138 8C.
/
/
1H-NMR (CDCl3): d 1.2 (m, Me4, Me6), 1.5 (s, br, Cp*,
332 (5), 301 (3), 236 (7), 262 (100). Anal. Found: C,
58.79; H, 6.40. Calc. for C34H43ClO3P2Ru: C, 58.49; H,
6.16%.
H5), 3.5 (t, 5.7 Hz, OMe), 4.8 (m, H4, H6). 11B-NMR
(CDCl3): d ꢂ
Hz, PPh3), 149.5 (d, Jꢀ
/
1.3. 31P-NMR(CDCl3): d 16.7 (t, Jꢀ
/
15.3
15.3 Hz, phosphite). 13C-NMR:
/
d 9.85 (s, Cp*), 22.50 (s, C4a, C6a, Me), 70.00 (s, C4,
C6, CH), 41.80 (d, 3.8 Hz, C5, CH2), 52.20 (s, OMe),
91.90 (s, Cp*), 130.72 (10.40, Cm), 134.60 (d, 12.50,
Cp), 136.20 (s, Co), n.o. (Ci).
4.4. Preparation of Cp*RuCl[MeOP(OCHMe)2CH2]2
(6)
4.4.1. Chloro-bis-(2-methoxi-4,6-dimethyl-1,3,2-l3-
dioxaphosphorinane)(h5-pentamethylcyclopentadienyl)-
ruthenium(II)
5. Supplementary material
Compound 2 (60 mg, 0.11 mmol) in THF (10 ml) gave
a brown solution after addition, at r.t. of 80 ml (0.53
mmol) of the mixture of phosphite isomers. After
heating under reflux for 15 min, the color of the solution
Crystallographic data for the structural analysis have
been deposited at the Cambridge Crystallographic Data
Centre, CCDC nos. 186379 and 186378 for compounds
5 and 6. Copies of the information may be obtained free
changed from dark-brown to yellowÁbrown. The reac-
/

´
´
J. Roman Torres-Lubian et al. / Journal of Organometallic Chemistry 663 (2002) 127Á
/133
133
[3] (a) K. Kirchner, K. Mauthner, K. Mereiter, R. Schmid, J. Chem.
Soc. Chem. Commun. (1993) 892;
of charge from The Director, CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK (Fax: ꢁ44-1223-336033;
e-mail: deposit@ccdc.cam.ca.uk or www: http://
www.ccdc.cam.ac.uk). Structural comparison of 5 and
6 with analogous molecules are described in the
supplementary material.
/
(b) K. Mauthner, K. Mereiter, R. Schmid, K. Kirchner, Inorg.
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Acknowledgements
[7] M.I. Bruce, B.C. Hall, N.N. Zaitseva, B.W. Skelton, A.H. White,
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This work was supported by grants from Conacyt.
The authors also acknowledge Conacyt for financial
support in the acquisition of the X-ray diffractometer
(No. F0084) and project 26352-E. Thanks to Washing-
ton University Mass Spectrometry Research Resource
(NIH, No. P41RR0954) for recording the mass spectra
and Marco Antonio Leyva and Ma. Luisa Rodriguez
for helping us with some X-ray diffraction studies and
NMR spectra, respectively.
[8] M.E. Navarro Clemente, P. Jua´rez Saavedra, M. Cervantes
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