Five-coordinate pentafluorobenzothiolate osmium(IV) complexes [Os(SC6F5)4(P(C6 H4X-4)3)] (X = OCH3, CH3, F, Cl or CF3): Solid and solution structural charac

Article abstract of DOI:10.1016/j.poly.2009.05.044

The reactions of OsO₄ with excess of HSC₆F₅ and P(C₆H₄X-4)₃ in ethanol afford the five-coordinate compounds [Os(SC₆F₅)₄(P(C₆H ₄X-4)

Full text of DOI:10.1016/j.poly.2009.05.044

Polyhedron 28 (2009) 2625–2634
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Five-coordinate pentafluorobenzothiolate osmium(IV) complexes
[Os(SC6F5)4(P(C6H4X-4)3)] (X = OCH3, CH3, F, Cl or CF3): Solid and solution
structural characterization
a
b
c
d
Maribel Arroyo a, , Consuelo Mendoza , Sylvain Bernès , Hugo Torrens , Hugo Morales-Rojas
*
a Centro de Química del Instituto de Ciencias de la BUAP, Edificio 193, Complejo de Ciencias, Ciudad Universitaria, San Manuel 72571, Puebla, Pue., Mexico
b DEP, Facultad de Ciencias Químicas, UANL, Guerrero y Progreso S/N, Col. Treviño, 64570 Monterrey N.L., Mexico
c División de Estudios de Posgrado, Facultad de Química, UNAM, Cd. Universitaria, 04510 México D.F., Mexico
d Centro de Investigaciones Químicas, UAEM, Av. Universidad 1001. Col. Chamilpa, Cuernavaca, Morelos, Mexico
a r t i c l e i n f o
a b s t r a c t
Article history:
The reactions of OsO4 with excess of HSC6F5 and P(C6H4X-4)3 in ethanol afford the five-coordinate com-
pounds [Os(SC6F5)4(P(C6H4X-4)3)] where X = OCH3 1a and 1b, CH3 2a and 2b, F 3a and 3b, Cl 4a and 4b or
CF3 5a and 5b. Single crystal X-ray diffraction studies of 1 to 5 exhibit a common pattern with an osmium
center in a trigonal-bipyramidal coordination arrangement. The axial positions are occupied by mutually
trans thiolate and phosphane ligands, while the remaining three equatorial positions are occupied by
three thiolate ligands. The three pentafluorophenyl rings of the equatorial ligands are directed upwards,
away from the axial phosphane ligand in the arrangement ‘‘3-up” (isomers a). On the other hand, 31P{1H}
and 19F NMR studies at room temperature reveal the presence of two isomers in solution: The ‘‘3-up” iso-
mer (a) with the three C6F5-rings of the equatorial ligands directed towards the axial thiolate ligand, and
the ‘‘2-up, 1-down” isomer (b) with two C6F5-rings of the equatorial ligands directed towards the axial
thiolate and the C6F5-ring of the third equatorial ligand directed towards the axial phosphane. Bidimen-
sional 19F–19F NMR studies encompass the two sub-spectra for the isomers a (‘‘3-up”) and b (‘‘2-up,
1-down”). Variable temperature 19F NMR experiments showed that these isomers are fluxional. Thus,
the 19F NMR sub-spectra for the ‘‘2-up, 1-down” isomers (b) at room temperature indicate that the
two S-C6F5 ligands in the 2-up equatorial positions have restricted rotation about their C–S bonds, but
this rotation becomes free as the temperature increases. Room temperature 19F NMR spectra of 3 and
5 also indicate restricted rotation around the Os–P bonds in the ‘‘2-up, 1-down” isomers (b). In addition,
as the temperature increases, the 19F NMR spectra tend to be consistent with an increased rate of the
isomeric exchange. Variable temperature 31P{1H} NMR studies also confirm that, as the temperature is
increased, the a and b isomeric exchange becomes fast on the NMR time scale.
Received 23 January 2009
Accepted 20 May 2009
Available online 27 May 2009
Keywords:
Five-coordinated osmium
Fluorinated thiolate ligands
Phosphane ligands
Variable temperature 19F NMR
Ó 2009 Elsevier Ltd. All rights reserved.
1. Introduction
1985, these authors reported [3] the rare carbonyl MIV compounds,
[M(SR)4(CO)], where the overall structure is similar to that of
The first molecular polythiolate-complexes of ruthenium and os-
mium, [M(SR)4(CH3CN)] (M = Ru, Os; R = C6HMe4-2,3,5,6 or
C6H2 Pr3-2,4,6), were reported by Koch and Millar in 1983 [1]. On
[M(SR)4(CH3CN)], with the CO occupying an axial position in the tri-
gonal-bipyramidal coordination arrangement, in contrast however
the three equatorial thiolates are oriented in the direction of the
CO (arrangement ‘‘3-up”). In a note, the authors remark the fact that
the 1H NMR spectra of all their [M(SR)4L] compounds are complex
and thus, for example [Ru(SC6HMe4-2,3,5,6)4(CH3CN)] in CDCl3
exhibits five singlets between d 6.6 and 7.2 ppm which are assigned
to the aromatic protons of the thiolate ligands, ten singlets between
d 1.8 and 2.7 ppm which are assigned to the methyl groups of the
thiolate ligands and two resonances at d 1.0 and 0.89 ppm assigned
to the CH3CN ligand. The interpretation was that both the ‘‘3-up” iso-
mer and the ‘‘2-up, 1-down” isomer are present in solution and that
these two isomers are not interconverting rapidly on the NMR time
scale due to a hindered rotation of the ligands at the Ru–Seq bonds.
i
these systems, the experimental M–Sax bond length is substantially
longer than the average of the Ru–Seq bond length, as theoretically
predicted for these diamagnetic low-spin d4 complexes [2]. In these
complexes two of the aromatic rings of equatorial thiolates are pro-
jected towards the axial CH3CN ligand and the other one is directed
towards the axial sulfur (arrangement ‘‘2-up, 1-down”). In addition,
these compounds were the first examples of five-coordinate ruthe-
nium and osmium complexes bearing a formal +4 oxidation state. In
* Corresponding author. Tel.: +52 222 2295500x7293; fax: +52 222 2295551.
E-mail addresses: slarroyo@siu.buap.mx, slmarroyo@hotmail.com (M. Arroyo).
0277-5387/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2009.05.044

2626
M. Arroyo et al. / Polyhedron 28 (2009) 2625–2634
Other five-coordinate ruthenium and osmium compounds with
these sterically hindered aromatic thiolate ligands were reported
[4,5]. In 1992 [5], for one of the compounds ‘‘2-up, 1-down”, the
authors found out that rotation about the RuIV–S bonds and C–S
bonds is not observed on the NMR time scale from room tempera-
ture to nearly 60 °C.
For a long time, we have also been involved in the synthesis and
reactivity studies of five-coordinate OsIV-polythiolate-complexes
[6–12], of general formula [OsX(SRF)3(PR3)] (X = Cl, SRF;
SRF = SC6F5, SC6F4H-4, SC6H4F-4, SC6H5; PR3 = tertiary phosphane).
Up to now, all members of these series -characterized by X-ray
crystallography- have shown, invariably, the orientation ‘‘3-up”
for the equatorial thiolates, probably because the axial tertiary
phosphane hinders that a RF group could lie near of such an axial
position. In general the structures in solution, according to 1H,
31P and 19F NMR spectra of some members of the series, are as ex-
pected if the solid-state structure is maintained in solution. Some
compounds however, undergo a measurable isomerisation that
had not been exhaustively investigated since generally only room
temperature NMR spectra were available, and it was not possible
to assign the isomers with certainty [7]. In fact, except for the
‘‘3-up” isomer, none other specific isomer had been accurately as-
signed in solution.
Fig. 1. Molecular structure of complex [Os(SC6F5)4(P(C6H4CH3-4)3)], 2a [22]. H
atoms have been omitted in the figure, and displacement ellipsoids are drawn at the
25% probability level.
On the other hand, restricted rotation of polyfluoro-phenyl/al-
kyl groups has been observed in a variety of coordination and orga-
nometallic compounds [12–21]. For example [Os(SC6F5)3
(SC6F4(SC6F5)-2)] and [Os(SC6F4H)2(SOC6F3H)(PPh3))] exhibited re-
stricted rotation of groups C6F5 or C6F4H about their C–S bonds
The yields of 1–5 and 6 depend strongly on the relative propor-
tion of phosphane ligand present always in excess to accomplish
the required reduction of the osmium. Thus, the compound
[Os(SC6F5)4(P(C6H4OCH3-4)3)] 1 is obtained in 70% yield when
the molar ratio OsO4:P(C6H4OCH3-4)3 is 1:6, while the yield drops
down to only 9% when this ratio is 1:1.75. The formation of 6 de-
pends just as well of this ratio.
The products were isolated by passage through a chromato-
graphic column. These osmium(IV) diamagnetic complexes were
characterized by elemental analyses, FAB+-mass spectrometry, sin-
gle crystal X-ray structure determinations and variable tempera-
ture 31P{1H} and 19F NMR studies.
+
*
[12], whereas complexes [IrCp {(CF2)nCF3}(PMe3)2] (n = 1, 2, 3, 5,
7, 9, 11) exhibited restricted rotation about their Ir–C
[13] and complex [Pd(C6F5)2(Me2–TpzT)] (Me2–TpzT
r
=
-bonds
2,4,6-
tris(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine) exhibited restricted
rotation about its Pd–C6F5 bonds [15]. The corresponding fluxional
processes can be accompanied by conformational changes in the
molecules and dynamic 19F NMR studies of fluoro-thiolate com-
plexes, [W(SC6F5)3(CO)Cp] [20], have revealed that isomeric forms
exist due to different orientations of the SC6F5 ligands and the iso-
mers undergo exchange as a result of rotations about W–SC6F5
bonds.
We now report the structural characterization of the com-
pounds [Os(SC6F5)4(P(C6H4X-4)3)], where X = OCH3 1, CH3 2, F 3,
Cl 4 or CF3 5, both in the solid-state by X-ray diffraction studies,
and in solution by 31P{1H} and 19F NMR investigation of structural
changes depending of temperature. These fluorinated systems offer
the possibility to distinguish clearly the structural details of these
types of five-coordinated osmium(IV) molecules and their struc-
tural changes.
The FAB-mass spectra show low intensities signals of M+ (X = Cl
4) or [MꢀH]+ (X = CF3 5, F 3, CH3 2). A common high intensity
signal on all the spectra is that corresponding to
[Os(SC6F5)3(P(C6H4X-4)3)]+. Also, peaks corresponding to
[P(C6H4X-4)3)]+ and [P(C6H4X-4)2)]+ ions, with medium to high
intensities are found on all FAB-mass spectra of compounds 1–5.
The NMR studies show that each one of these products exists as
a pair of isomers (a) and (b).
In the solid-state, compounds [Os(SC6F5)4(P(C6H4X-4)3)] 1a–5a
share the trigonal-bipyramidal coordination geometry invariably
observed for all OsIV complexes formulated as [OsX(SRF)3(PR3)]
(X = Cl, SC6F5, SC6F4H-4; SRF = SC6F5, SC6F4H-4; PR3 = tertiary phos-
phane) [6–8,10,11] (Fig. 1). The nature of the X substituent in the
phosphane has none or little influence on the arrangement of li-
gands around the OsIV ion. Axial positions are occupied by mutu-
ally trans thiolate and phosphane ligands, with S1–Os1–P1 angles
in the short range 173.20(4)–177.23(4)°. Apparently there is no
correlation between structural parameters and the trans influence
of the phosphanes present in complexes 1a–5a. Variations ob-
served for Os1–S1 and Os1–P1 bond lengths are limited and virtu-
ally fall within the standard uncertainties for these parameters,
0.001–0.002 Å. Within experimental accuracy, any attempts to cor-
relate phosphane basicity and solid-state structures would then be
of questionable significance. Equatorial coordination sites are
occupied by three thiolate ligands, with pentafluorophenyl groups
2. Results and discussion
The reactions of OsO4 with excess of HSC6F5 and P(C6H4X-4)3 in
ethanol afford the pentacoordinated, diamagnetic compounds
[Os(SC6F5)4(P(C6H4X-4)3)] where X = OCH3 1, CH3 2, F 3, Cl 4 or
CF3 5. A general preliminary information about the preparation
of these compounds has been mentioned [9]. Pentafluorobenze-
nethiol is dissolved in ethanol and then osmium tetraoxide is
added. The mixture quickly turns black, the phosphane is added
and the mixture refluxed turning green/brown. In addition to the
formation of [Os(SC6F5)4(P(C6H4X-4)3)], the recently reported per-
sulfurated complex,
[12] 6, is present
[Os(SC6F5)3(SC6F4(SC6F5)-2)]
as an additional product of these reactions.
Ethanol
[Os(SC6F5)4(P(C6H4X-4)3)] + [Os(SC6F5)3(SC6F4(SC6F5)-2)]
OsO4 + HSC6F5(excess) + P(C6H4X-4)3(excess)
6
1-5

M. Arroyo et al. / Polyhedron 28 (2009) 2625–2634
2627
Table 2
oriented away from the axial phosphane ligand, in the arrange-
ment ‘‘3-up” (isomer a), in order to minimize the overall steric hin-
drance for peripheral phenyl rings in this molecule.
Selected torsion angles in compounds 1a–5a.
d (°)
1a
2a
3a
4a
5a
Although molecular structures are similar for all studied com-
plexes, two points deserve to be commented. We previously re-
ported that in the complex [Os(SC6F5)4(PPh3)], which crystallizes
with three crystallographically independent molecules in the
asymmetric unit [10], the axial thiolate ligand gives rise to rota-
mers due to a non-restricted rotation about Os–S(ax) and S(ax)–
S2–Os–S1–C19
S3–Os–S1–C19
S4–Os–S1–C19
ꢀ61.3(2)
ꢀ178.8(2)
62.9(2)
ꢀ64.9(2)
178.2(2)
60.9(2)
54.1(3)
170.0(3)
ꢀ71.7(3)
ꢀ59.18(16)
ꢀ174.44(16)
71.08(16)
ꢀ53.9(3)
ꢀ169.7(3)
71.1(3)
C(ipso)
r-bonds. Similar results, although of limited extent, may
be found among compounds 1a–5a by inspecting the S(eq)–Os–
S(ax)–C(ipso) torsion angles (Table 2). On the basis of these data,
complexes 1a–5a can be roughly classified in two groups: 1a–2a
(S4–Os–S1–C19 torsion angle close to 60°) and 3a–5a (S4–Os–
S1–C19 torsion angle close to 71°). This flexibility of orientation
observed for the axial thiolate ligand is also present for the equa-
torial ligands, which experiment libration motions, particularly
for S3-thiolate. Again, complexes 1a and 2a are differentiated from
3a–5a (Fig. 2).
The second point of interest is about 3a, which is the only mem-
ber of this series crystallizing in a non-centrosymmetric achiral
space group (NA crystal-structure type in the Flack’s classification
[23]). The measured crystal revealed to be a sample twinned by
inversion, with components of the twin in the ratio
0.72(1):0.28(1) (see Section 4 and Fig. 2). A non-racemic mixture
of configurations 0.72-K, 0.28-D was thus crystallized in the case
of 3a (the chiral axis is defined by P–Os bond). The other crystal-
lized complexes of the series (1a, 2a, 4a and 5a) are necessarily
K,D-racemates, as they crystallize in centrosymmetric space
groups (CA crystal-structure type in the Flack’s classification
[23]). In other words, 3a in the solid-state represents an example
of a co-crystallization associated with a partial spontaneous
resolution. The factor promoting this resolution should probably
be searched in crystallization conditions rather than in compound
formulas or intermolecular interactions in the solid-sate. Single
crystals were obtained either by crystallization from an
acetone–ethanol solution of a powder sample, or directly by slow
evaporation of chromatographed fractions (eluent: hexane-CH2Cl2)
of the crude from the synthesis reactions. On the other hand, mul-
tiple crystal structure determinations on multiple crystallization
crops would be necessary, in order to check if 3a is systematically
resolved in a more or less similar enantiomeric excess upon crys-
tallization, and that such a resolution never occur for other
complexes.
Fig. 2. A least-squares overlay [22] of molecular structures of complexes 1a–5a. For
the sake of clarity, F atoms of thiolate and of CF3 groups, and all H atoms were
omitted in the figure. The fit is carried out considering Os,
(coordination sphere), while other atoms are free. In the case of complexes
crystallizing in centrosymmetric space groups (blue bonds), configuration has
been arbitrarily selected. For 3a (green bonds), both and configurations,
forming a non-racemic mixture in the crystal, have been fitted.
P and S atoms
D
K
D
products the osmium center displays the same arrangement ‘‘3-
up” for the equatorial thiolate ligands, the NMR studies show that
each one of these products exists as the pair of isomers ‘‘3-up” (a)
and ‘‘2-up, 1-down” (b) as depicted in the following scheme
(Scheme 1).
The room temperature 31P{1H} NMR spectra of each product 1–
5, and the previously reported [Os(SC6F5)4(P(C6H5)3)] [7] 7, show
two singlets suggesting the presence of two isomers. In all cases,
the signal at low field corresponds to the more abundant isomer
Although TLC for each of the products 1–5 shows only one spot,
and in all the determined X-ray diffraction structures of these
Table 1
X-ray parameters.
Complex
1a (X = OCH3)
2a (X = CH3)
3a (X = F)
4a (X = Cl)
5a (X = CF3)
Chemical formula
Fw
Space group
C45H21F20O3OsPS4
1339.03
P1
C45H21F20OsPS4
1291.03
P21/c
C42H12F23OsPS4
1302.93
Pn
C42H12Cl3F20OsPS4
1352.28
P1
C45H12F29OsPS4ꢁH2O
1470.97
P21/c
ꢀ
ꢀ
a/Å
b/Å
c/Å
12.6081(13)
13.5869(12)
14.4279(14)
92.608(5)
96.775(8)
97.287(7)
2429.9(4)
2
12.654(3)
14.7363(19)
25.476(3)
90.00
97.568(13)
90.00
4709.3(15)
4
3.032
11.2573(11)
11.6399(12)
17.8021(16)
90.00
104.753(7)
90.00
2255.8(4)
2
3.175
11.9708(6)
13.5087(6)
14.9035(8)
94.247(4)
97.503(4)
108.130(3)
2253.90(19)
2
12.3311(9)
11.8013(8)
37.392(2)
90
96.414(6)
90
5407.4(6)
4
2.677
a
/°
b/°
c
/°
V/Å3
Z
l
/mmꢀ1
2.946
3.345
R1, wR2 [I > 2
r
(I)]a
0.0373, 0.0797
0.0520, 0.0853
1.830
0.0385, 0.0864
0.0583, 0.0961
1.821
0.0249, 0.0555
0.0290, 0.0574
1.918
0.0370, 0.0663
0.0636, 0.0746
1.993
0.0509, 0.1131
0.0881, 0.1322
1.807
R1, wR2 (all data)a
Dcalc./g cmꢀ3
T/°C
23(1)
23(1)
23(1)
23(1)
23(1)
rffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
P
P
2
jjFo jꢀjFc
wðF2o ꢀF2c
Þ
jj ; wR2
¼
.
2
a
P
P
R1
¼
wðF2o
Þ
jFo
j

2628
M. Arroyo et al. / Polyhedron 28 (2009) 2625–2634
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
S
F
F
S
F
F
F
F
S
S
S
S
F
F
F
F
F
F
Os
Os
S
S
F
F
F
F
F
F
F
F
F
F
P
P
X
X
X
X
X
X
isomer: "3-up"
isomer: "2-up, 1-down"
a
b
Scheme 1.
Table 3
31P{1H} NMR data in CDCl3 at room temperature.
Product
Isomer a ‘‘3-up” d(ppm)
Isomer b ‘‘2-up, 1-down” d(ppm)
Integral ratio a/b
[Os(SC6F5)4(P(C6H4OCH3-4)3)] 1
[Os(SC6F5)4(P(C6H4CH3-4)3)] 2
[Os(SC6F5)4(P(C6H5)3)] 7
[Os(SC6F5)4(P(C6H4F-4)3)] 3
[Os(SC6F5)4(P(C6H4Cl-4)3)] 4
[Os(SC6F5)4(P(C6H4CF3-4)3)] 5
3.49
5.34
7.44
5.69
6.59
8.52
0.82
2.83
4.88
2.93
4.03
6.08
2.4
2.0
3.0
4.4
3.8
4.4
a
a
a
2 (pax
)
6 (peq
)
12 (oeq
)
b
2
(meq-2up
)
PPM -162.26 -162.30 -162.34 -162.38 -162.42 -162.46
T = 22 °C
a
12 (meq
)
a
2 (pax
)
a
b
2
4 (max
)
(meq-2up
)
b
2
a
4 (oax
b
2
(max
(peq-2up
)
b
1
(pax
b
2
)
b
2
b
2
b
2
b
1
)
b
)
(meq-1down
)
eq-2up b
(o’
)
(m’eq
2
2
(oeq-1down
)
(peq-1down
)
-2up
)
(oeq-2up
)
(oax
)
-128.0
-130.0
-132.0
-150.0
-152.0
-158.0
-160.0
-162.0
-164.0
Fig. 3. 19F NMR spectrum of [Os(SC6F5)4(P(C6H4CH3-4)3)] 2 at 22 °C in C6D5CD3. The letter-labels identify the isomers: a, isomer ‘‘3-up”; b, isomer ‘‘2-up, 1-down”. Numbers
correspond to the relative integrals, which show that the ratio a/b is 2:1 in this product.

M. Arroyo et al. / Polyhedron 28 (2009) 2625–2634
2629
80 °C
70 °C
55 °C
40 °C
23 °C
0 °C
Fig. 4. 19F–19F COSY NMR spectrum of [Os(SC6F5)4(P(C6H4CH3-4)3)] 2 at 22 °C.
-30 °C
-50
°C
which, as deduced from the 19F NMR studies below, is the ‘‘3-up”
isomer (a). Table 3 indicates the relative abundances calculated
from the 31P{1H} NMR spectra at room temperature, including
the corresponding data from 7 for comparison purposes. These rel-
ative abundances are the same as those calculated from the 19F
NMR spectra.
Although the relative abundance of isomer a seems to growth
with the electronegativity of the X substituent on the phosphane
P(C6H4X-4)3, the a/b ratio is probably a combination of electronic
factors influencing the ability to undergo the required inversion
of configuration at the sulfur atoms as well as solvent-complex
-70 °C
PPM
9.5
7.5
5.5
3.5
Fig. 6. Variable temperature 31P{1H} NMR spectra of [Os(SC6F5)4(P(C6H4CH3-4)3)] 2
in C6D5CD3
interactions with the changing dipolar moments of the substituted
phenyl rings.
90 °C
85 °C
80 °C
75 °C
70 °C
50 °C
24 °C
−
50 °C
−70 °C
-128.0 -132.0 -136.0 -140.0 -144.0 -148.0 -152.0 -156.0 -160.0 -164.0
Fig. 5. Variable temperature 19F NMR spectra of [Os(SC6F5)4(P(C6H4Cl-4)3)] 4 in C6D5CD3.

2630
M. Arroyo et al. / Polyhedron 28 (2009) 2625–2634
Room temperature 19F NMR spectra of each product 1–5, and
ortho, para and meta signals (A2BC2 spin system, relative integrals
2:1:2). The group of five signals from the two equatorial thiolate
ligands in the orientation 2-up is consistent with two equivalent
C6F5-groups restricted to rotate about their C–S bonds, where the
two ortho (as well as meta) fluorine atoms in each ring are mag-
netically non-equivalent. Of course, the relative integrals be-
tween signals of isomer a and signals of isomer b are specific
of each product. Fig. 3 shows the 19F NMR spectrum at room
temperature of the product 2 (X = CH3), where the described
assignments are illustrated whereas Fig. 4 shows the correspond-
ing 19F–19F NMR spectrum.
the previously reported [Os(SC6F5)4(P(C6H5)3)] [7,10] 7, exhibit
two independent sub-spectra, one for each of the isomers present
in solution. 19F–19F NMR experiments were used to unambigu-
ously identify each set of signals. The sub-spectrum of the isomer
a ‘‘3-up” consists of two groups of signals with three absorptions
each, corresponding to ortho, para and meta-fluorine atoms of
C6F5 rings, at low, medium and high field, respectively [24,25].
One of these groups arises from the three equivalent equatorial
thiolate ligands (A2BC2 spin system, relative integrals 6:3:6),
and the second group from the axial thiolate ligand (another
A2BC2 spin system, relative integrals 2:1:2). The sub-spectrum
of the isomer b ‘‘2-up, 1-down” consists of three groups of sig-
nals: the group from one equatorial thiolate ligand in the orien-
tation 1-down, which consists of three ortho, para and meta
absorptions (A2BC2 spin system, relative integrals 2:1:2), the
group from the two equatorial thiolate ligands in the orientation
2-up, which consists of five ortho, ortho0, para, meta and meta0
signals (AA0BCC0 spin system, relative integrals 2:2:2:2:2), and
the group of the axial thiolate ligand, which consists of three
For all ‘‘3-up” isomers, the room temperature 19F–19F NMR spec-
tra show a significant magnetic coupling between Fortho–equatorial and
Fortho–axial nuclei. These nuclei are eight bonds apart with a S–Os–S
intermediate fragment and therefore, a conventional contact cou-
pling mechanism is unlikely. On the other hand, the three equatorial
thiolates on the ‘‘3-up” isomers form a bowl-like cavity which sur-
rounds the axial thiolate with a very close spatial proximity to the
ortho fluorine nuclei and therefore suggesting a through-space cou-
pling mechanism.
(a) X = CF3 on the phosphane
80 °C
75 °C
a
70 °C
50 °C
39
b
b
3
6
25 °C
-50 °C
PPM -63.32 -63.36 -63.40 -63.44 -63.48 -63.52 -63.56 -63.60
(b) X = F on the phosphane
90 °C
a
13
85 °C
80 °C
70 °C
50 °C
b
2
b
1
24 °C
-50 °C
-70 °C
PPM -105.6 -106.0 -106.4 -106.8
1
-
Fig. 7. Variable temperature 19F NMR spectra on the phosphane–fluorine region of (a) [Os(SC6F5)4(P(C6H4CF3-4)3)] 5 and (b) [Os(SC6F5)4(P(C6H4F-4)3)] 3 in C6D5CD3; a
corresponds to isomer ‘‘3-up” and b to isomer ‘‘2-up, 1-down”. Numbers correspond to the relative integrals, which show that the ratio a/b is 4.4:1 in these products.

M. Arroyo et al. / Polyhedron 28 (2009) 2625–2634
2631
The 19F NMR spectra of each product 1–5, and 7, registered from
ꢀ80 °C to +90 °C, indicate that these products undergo fluxional
processes in solution. Fig. 5 shows variable temperature 19F NMR
spectra of product 4 (X = Cl) in C6D5CD3. In general, for isomers b
‘‘2-up, 1-down” in the series 1–5 and 7, as the temperature is in-
creased, the two ortho and ortho0 signals (relative intensities 2:2),
from the two equivalent 2-up equatorial thiolates, broaden and
eventually coalesce giving rise to a single ortho signal (intensity
4) at ca. 85–90 °C. The coalescence of the corresponding meta and
meta0 signals follows a similar pattern, while at high temperatures
the corresponding para absorption of these 2-up equatorial thiolate
ligands exhibits chemical shift almost coincident with the para sig-
nal of the 1-down equatorial thiolate of the same isomer b, and with
the para signal of the three 3-up equatorial thiolates of the isomer a.
As the temperature is increased, the 19F NMR spectra of 1–5, and 7
tend to simplify until they resemble the spectra of the isomer a. The
coalescence at high temperatures (85–90 °C) of the ortho and ortho0
signals from the two 2-up equatorial thiolates is consistent with
free C–S bond rotations at these temperatures, with estimated
[Os(SC6F5)4(P(C6H4X-4)3)] where X = OCH3 1a and 1b, CH3 2a and
2b, F 3a and 3b, Cl 4a and 4b or CF3 5a and 5b. Single crystal X-
ray diffraction studies of 1–5 exhibit a common pattern with an os-
mium center in a trigonal-bipyramidal coordination arrangement
with the axial positions occupied by mutually trans thiolate and
phosphane ligands and the three C6F5-rings of the equatorial thio-
late ligands directed towards the axial thiolate ligand (isomers a
‘‘3-up”). On the other hand, 31P{1H} and 19F NMR studies at room
temperature reveal accurately the presence of two isomers in
solution: the ‘‘3-up” isomer (a) above mentioned, and the ‘‘2-up,
1-down” isomer (b) with two C6F5-rings of the equatorial ligands
directed towards the axial thiolate and the C6F5-ring of the third
equatorial ligand directed towards the axial phosphane. In addi-
tion, at low temperatures, the NMR studies reveal restricted rota-
tions about specific bonds in the molecules. As the temperature
increases, the 19F and 31P{1H} NMR spectra tend to be consistent
with an increased rate of these rotations about bonds in the iso-
mers, as well as with an increased rate of the isomeric exchange.
D
Gà values of 69–70 kJmolꢀ1. In addition, the tendency of both
4. Experimental
19F NMR sub-spectra of the isomers a and b (low temperatures)
to merge into a single spectrum corresponding to the isomer a (high
temperatures) suggests that a rapid conversion between isomers a
and b occurs also and simultaneously. To investigate this process
further, we have measured the 31P{1H} NMR spectra at variable
temperature and found that, as the temperature is increased, both
singlets from isomers a and b broaden and decrease in height,
although at 80 °C (or inclusive 95 °C) their coalescence is still not
completed (Fig. 6). This is a reversible process since the original
spectra are obtained as the temperature is restored back. We con-
clude that two fluxional processes are being simultaneously ob-
served: the C–S bond rotation of the two 2-up equatorial thiolates
in the isomer b and the conversion between isomers a and b which
involves inversion of configuration at the sulfur atoms.
All reactions were carried out under argon atmospheres using
conventional Schlenk-tube techniques. Thin-layer chromatography
(TLC) (Merck, silica gel 60 F254) was used to monitor the progress of
the reactions under study with hexane–dichloromethane (4:1) as
eluent. The starting materials: osmium tetraoxide, pentafluoroben-
zenethiol and phosphanes were used as received from Aldrich
Chemical Co. and Strem. The products were separated by passage
through a silica gel chromatographic column with hexanes–dichlo-
romethane as eluent.
Melting points were obtained on a Fisher–Johns melting point
apparatus and are uncorrected.
Infrared spectra were recorded on a 750 Nicolet Fourier Trans-
form Magna-IR Spectrometer. The samples were prepared as KBr
pellets. Data are expressed in wavenumbers (cmꢀ1) with relative
intensities (vs = very strong, s = strong, m = medium, w = weak).
31P{1H}, 19F, and COSY 19F–19F NMR spectra were recorded on a
Varian Mercury VX400 spectrometer operating at 162 MHz, and
376 MHz, respectively. 31P{1H} NMR spectra were also recorded
on a Varian Mercury VX300 spectrometer operating at 121 MHz.
Chemical shifts are relative to H3PO4 d = 0 (31P) and CCl3F d = 0
Except for subtle differences in chemical shifts and some varia-
tions in the relative positions of the para and meta signals, the 19F
NMR spectra in the C6F5-region of these products 1–5 and 7 are all
comparable.
In addition, the room temperature 19F NMR spectrum of 5
(X = CF3), in the CF3-region of the phosphane ligand, exhibits: one
singlet corresponding to equivalent CF3 groups at the para-posi-
tions of the phenyl substituents of the phosphane in the isomer
‘‘3-up” 5a and two singlets (relative integrals 3:6) corresponding
to non-equivalent CF3 groups of the phenyl substituents of the
phosphane in the isomer ‘‘2-up, 1-down” 5b. The corresponding
spectrum of 3 (X = F) on the fluorine-region of the phosphane, also
exhibits the same pattern of signals, corresponding to the para-
fluorine nuclei in the phenyl substituents of the phosphane ligand
of the isomers: 3a: one doublet of triplets of triplets, corresponding
to three equivalent C6H4F-4 substituents in this isomer, and 3b:
two doublets of triplets of triplets, relative integrals 2:1, corre-
sponding to two equivalent C6H4F-4 rings plus another non-equiv-
alent C6H4F-4 ring one in this isomer ‘‘2-up, 1-down”. In each of
these two products 3 or 5, these additional signals at low field tend
to coalesce into only one signal as the temperature increases
(Fig. 7). The spectra of these two products 3 and 5 at low field cor-
roborate the existence of the isomers ‘‘3-up” and ‘‘2-up, 1-down” in
solution and show that, at low temperatures, the isomer ‘‘2-up, 1-
down” exhibits restricted rotation of the osmium–phosphorous
bond imposed by the pending thiolate ring giving rise to a system
involving an unusual asymmetrical phosphane.
(
19F), using C6D5CD3 and CDCl3 as solvents. The Gà values re-
D
ported in this paper have been calculated from variable tempera-
ture (VT) 19F NMR data with the Eyring equation, estimating the
rate constant at the coalescence temperature on the basis of the
chemical shift difference at low temperature.
Positive ion FAB mass spectra were recorded on a Jeol JMS-
SX102A mass spectrometer operated at an accelerating voltage of
10 kV. Samples were desorbed from
a 3-nitrobenzyl alcohol
(NOBA) matrix using 3 keV xenon atoms. Mass measurements in
FAB are performed at a resolution of 3000 using magnetic field
scans and the matrix ions as the reference material.
Elemental analyses were determined by Galbraith Laboratories
Inc.
4.1. [Os(SC6F5)4(P(C6H4OCH3-4)3)] 1
Pentafluorobenzenethiol (0.8 mL, 6.0 mmol) was dissolved in
ethanol (15 mL), then osmium tetraoxide (0.25 g, 1.0 mmol) was
added. The mixture rapidly turned black. P(C6H4OCH3-4)3 (0.62 g,
1.75 mmol) was added and the mixture refluxed for 4 h turning
green. The solvent was distilled off under vacuum and the solid
product was purified through a silica gel chromatographic column
eluted with hexane–dichloromethane 4:1. Two fractions with com-
pounds 1 and [Os(SC6F5)3(SC6F4(SC6F5)-2)] [12] 6 were separated
3. Conclusions
We report here the reactions of OsO4 with HSC6F5 and P(C6H4X-
4)3 in ethanol to afford the five-coordinate compounds

2632
M. Arroyo et al. / Polyhedron 28 (2009) 2625–2634
and dried under vacuum at room temperature for 4 h. Single crys-
tals of 1 were obtained by slow evaporation of an acetone–ethanol
solution of the compound.
[M+ꢀ2(SC6F5)ꢀH], 304 (21) [P(C6H4CH3)3+], 213 (17) [P(C6H4-
CH3)2+].
[Os(SC6F5)3(SC6F4(SC6F5)-2)] [12] 6 (0.035 g, 3%).
[Os(SC6F5)4(P(C6H4OCH3-4)3)] 1. Green (0.12 g, 9%). Anal. Calc.
for C45H21F20O3OsPS4: C, 40.36; H, 1.58; S, 9.58. Found: C, 40.32;
H, 1.66; S, 9.52%. Mp: 193 °C, decomposes. IR (KBr, cmꢀ1): mthiolate
1514(vs), 1486(vs), 1090(vs), 982(vs), 849(s); mphosphane 1593(s),
1567(w), 1502(vs), 1444(w), 1289(s), 1259(s), 1184(s), 1090(vs),
1026(w), 833(w), 800(w), 540(w). 31P{1H} NMR (CDCl3, RT),
d(ppm): isomer ‘‘3-up”, d = 3.49 (s, 2.4P, 2.4(1P(C6H4OCH3-4)3));
isomer ‘‘2-up, 1-down”, d = 0.82 (s, 1.0P, 1P(C6H4OCH3-4)3). 19F
NMR (C6D5CD3, RT), d(ppm): isomer ‘‘3-up”, d = ꢀ129.24 (br s,
4.3. [Os(SC6F5)4(P(C6H4F-4)3)] 3
The procedure is analogous to that for 1: reflux time 3 h. Prod-
ucts 3 and 6. Starting quantities: pentafluorobenzenethiol (0.8 mL,
6.0 mmol), osmium tetraoxide (0.25 g, 1.0 mmol), P(C6H4F-4)3
(0.81 g, 2.55 mmol). Single crystals of 3 were obtained by slow
evaporation of a hexane–dichloromethane 4:1 solution of the
compound.
[Os(SC6F5)4(P(C6H4F-4)3)] 3. Brown (0.57 g, 44%). Anal. Calc. for
C42H12F23OsPS4: C, 38.72; H, 0.93; S, 9.84. Found: C, 38.82; H,
0.97; S, 9.76%. Mp: 178 °C, decomposes. IR (KBr, cmꢀ1): mthiolate
1512(vs), 1491(vs), 1091(vs), 982(vs), 852(w); mphosphane 1592(w),
1491(vs), 1394(w), 1244(w), 1165(s), 1091(vs), 833(w), 530(w).
31P{1H} NMR (CDCl3, RT), d(ppm): isomer ‘‘3-up”, d = 5.69 (d,
4.4P, 4.4(1P(C6H4F-4)3)); isomer ‘‘2-up, 1-down”, d = 2.93 (d, 1.0P,
1P(C6H4F-4)3). 19F NMR (C6D5CD3, RT), d(ppm): isomer ‘‘3-up”,
3
14.4Fo, 2.4(3SC6F5-eq)), d = ꢀ132.14 (d, 4.8Fo, 2.4(1SC6F5-ax), JFo–
3
Fm = 23.32 Hz), d = ꢀ150.99 (t, 7.2Fp, 2.4(3SC6F5-eq), JFp–Fm
=
20.69 Hz), d = ꢀ161.98 (br m, 14.4Fm, 2.4(3SC6F5-eq)),
3
d = ꢀ162.44 (t, 2.4Fp, 2.4(1SC6F5-ax), JFp–Fm = 20.69 Hz), d =
ꢀ164.24 (m, 4.8Fm, 2.4(1SC6F5-ax)); isomer ‘‘2-up, 1-down”,
3
d = ꢀ127.05 (d, 2Fo, 1SC6F5-eq-‘‘1-down”, JFo–Fm = 25.96 Hz),
d = ꢀ130.27 (br s, 2Fo, ½(2SC6F5)-eq-‘‘2-up”), d = ꢀ131.09 (br s,
2Fo0, ½(2SC6F5)-eq-‘‘2-up”), d = ꢀ131.77 (m, 2Fo, 1SC6F5-ax), d =
3
3
4
ꢀ151.32 (t, 2Fp, 2SC6F5-eq-‘‘2-up”, JFp–Fm = 19.18 Hz), d = ꢀ151.37
d = ꢀ105.60 (dtt, 13.2Fp, 4.4(1P(C6H4F-4)3), JFp–Hm = 5.70 Hz, JFp–
3
(t, 1Fp, 1SC6F5-eq-‘‘1-down”, JFp–Fm = 19.18 Hz), d = ꢀ158.16 (t,
Ho = 3.99 Hz, 5JFp–P = 2.14 Hz), d = ꢀ129.29 (br s, 26.4Fo,
3
3
1Fp, 1SC6F5-ax, JFp–Fm = 20.69 Hz), d = ꢀ160.83 (m, 2Fm, 1SC6F5-
4.4(3SC6F5-eq)), d = ꢀ132.02 (d, 8.8Fo, 4.4(1SC6F5-ax), JFo–Fm
=
3
eq-‘‘1-down”), d = ꢀ162.30 (t, 2Fm, ½(2SC6F5)-eq-‘‘2-up”, JFm–
23.32 Hz),
d = ꢀ150.04
(t,
13.2Fp,
4.4(3SC6F5-eq),
3JFp–
F = 23.32 Hz), d = ꢀ162.70 (br m, 2Fm0, ½(2SC6F5)-eq-‘‘2-up”),
d = ꢀ163.65 (m, 2Fm, 1SC6F5-ax). FAB+ꢀMS {m/z (%) [fragment]}:
1141 (17) [M+ꢀ(SC6F5)], 352 (8) [P(C6H4OCH3)3+], 245 (14)
[P(C6H4OCH3)2+].
Fm = 20.69 Hz), d = ꢀ161.54 (br m, 26.4Fm, 4.4(3SC6F5-eq)),
3
d = ꢀ161.65 (t, 4.4Fp, 4.4(1SC6F5-ax), JFp–Fm = 20.69 Hz), d =
ꢀ163.89 (m, 8.8Fm, 4.4(1SC6F5-ax)), isomer ‘‘2-up, 1-down”,
d = ꢀ105.34 (dtt, 2Fp, 1P(C6H4F-4)3, 3JFp–Hm = 5.71 Hz, 4JFp–
5
[Os(SC6F5)3(SC6F4(SC6F5)-2)] [12] 6 (0.035 g, 3%).
Ho = 3.98 Hz, JFp–P = 2.1 Hz), d = ꢀ106.55 (dtt, 1Fp, 1P(C6H4F-4)3,
4
5
When the starting quantities were: pentafluorobenzenethiol
(0.8 mL, 6.0 mmol), osmium tetraoxide (0.25 g, 1.0 mmol) and
P(C6H4OCH3-4)3 (2.10 g, 6.0 mmol), complex 6 was not obtained
and the only isolated complex was [Os(SC6F5)4(P(C6H4OCH3-4)3)]
1 in 70% yield (0.94 g).
3JFp–Hm = 5.7 Hz, JFp–Ho = 3.9 Hz, JFp–P = 2 Hz), d = ꢀ127.23 (d, 2Fo,
3
1SC6F5-eq-‘‘1-down”, JFo–Fm = 24.83 Hz), d = ꢀ130.34 (br s, 2Fo,
½(2SC6F5)-eq-‘‘2-up”), d = ꢀ131.20 (br s, 2Fo0, ½(2SC6F5)-eq-‘‘2-
up”), d = ꢀ131.78 (m, 2Fo, 1SC6F5-ax), d = ꢀ149.92 (t, 1Fp, 1SC6F5-
3
eq-‘‘1-down”, JFp–Fm = 20.69 Hz), d = ꢀ150.38 (t, 2Fp, 2SC6F5-eq-
3
3
‘‘2-up”, JFp–Fm = 20.69 Hz), d = ꢀ157.29 (t, 1Fp, 1SC6F5-ax, JFp–
Fm = 20.69 Hz), d = ꢀ159.94 (m, 2Fm, 1SC6F5-eq-‘‘1-down”),
4.2. [Os(SC6F5)4(P(C6H4CH3-4)3)] 2
3
d = ꢀ161.87 (t, 2Fm, ½(2SC6F5)-eq-‘‘2-up”, JFm–F = 21.82 Hz),
The procedure is analogous to that for 1: reflux time 3 h. Prod-
ucts 2 and 6. Starting quantities: pentafluorobenzenethiol (0.8 mL,
6.0 mmol), osmium tetraoxide (0.25 g, 1.0 mmol), P(C6H4CH3-4)3
(0.90 g, 2.95 mmol). Single crystals of 2 were obtained by slow
evaporation of an acetone–ethanol solution of the compound.
[Os(SC6F5)4(P(C6H4CH3-4)3)] 2. Green (0.64 g, 50%). Anal. Calc.
for C45H21F20OsPS4: C, 41.86; H, 1.64; S, 9.93. Found: C, 41.75; H,
1.71; S, 9.92%. Mp: 185 °C, decomposes. IR (KBr, cmꢀ1): mthiolate
1512(vs), 1488(vs), 1090(vs), 981(vs), 851(s); mphosphane 1488(vs),
1393(w), 1090(vs), 809(w), 631(w), 525(w), 512(w). 31P{1H} NMR
(CDCl3, RT), d(ppm): isomer ‘‘3-up”, d = 5.34 (s, 2.0P,
2(1P(C6H4CH3-4)3)); isomer ‘‘2-up, 1-down”, d = 2.83 (s, 1.0P,
1P(C6H4CH3-4)3). 19F NMR (C6D5CD3, RT), d(ppm): isomer ‘‘3-up”,
d = ꢀ129.23 (br s, 12Fo, 2(3SC6F5-eq)), d = ꢀ132.07 (d, 4Fo,
d = ꢀ162.31 (br m, 2Fm0, ½(2SC6F5)-eq-‘‘2-up”), d = ꢀ163.27 (m,
2Fm, 1SC6F5-ax). FAB+ꢀMS {m/z (%) [fragment]}: 1303 (2)
[M+ꢀH], 1285 (1) [M+ꢀF], 1209 (2) [M+ꢀ(C6H4F)], 1105 (100)
[M+ꢀ(SC6F5)],
938
(3)
[M+ꢀ(SC6F5)ꢀ(C6F5)],
905
(3)
[M+ꢀ2(SC6F5)ꢀH], 316 (68) [P(C6H4F)3+], 221 (58) [P(C6H4F)2+].
[Os(SC6F5)3(SC6F4(SC6F5)-2)] [12] 6 (0.08 g, 7%).
4.4. [Os(SC6F5)4(P(C6H4Cl-4)3)] 4
Pentafluorobenzenethiol (0.8 mL, 6.0 mmol) was dissolved in
ethanol (15 mL), then osmium tetraoxide (0.25 g, 1.0 mmol) was
added. The mixture rapidly turned black. P(C6H4Cl-4)3 (0.67 g,
1.82 mmol) was added and the mixture was stirred at room tem-
perature for 9 h. The resulting solution was concentrated at ca.
50% under reduced pressure to give a brown precipitate. It was fil-
tered off, washed with ethanol (15 mL) and hexane (15 mL) and
dried under vacuum. Additional purification was necessary
through a silica gel chromatographic column with hexane–dichlo-
romethane 4:1 as eluent. Slow evaporation of the eluent affords
brown crystals of 4. With scope for increasing the yield of 4, the fil-
trate was refluxed for 3 h giving a green product, 6, which was also
purified through a silica gel chromatographic column with hex-
ane–dichloromethane 4:1 as eluent.
[Os(SC6F5)4(P(C6H4Cl-4)3)] 4. Brown (0.14 g, 10%). Anal. Calc. for
C42H12Cl3F20OsPS4: C, 37.30; H, 0.89; S, 9.48. Found: C, 37.21; H,
0.95; S, 9.43%. Mp: 200 °C, decomposes. IR (KBr, cmꢀ1): mthiolate
1513(vs), 1483(vs), 1085(vs), 980(vs), 853(s); mphosphane 1483(vs),
1390(w), 1085(vs), 1013(w), 822(w), 749(w), 548(w), 503(w).
31P{1H} NMR (CDCl3, RT), d(ppm): isomer ‘‘3-up”, d = 6.59 (s, 3.8P,
3
2(1SC6F5-ax), JFo–Fm = 23.32 Hz), d = ꢀ151.02 (t, 6Fp, 2(3SC6F5-eq),
3JFp–Fm = 20.69 Hz), d = ꢀ162.04 (br s, 12Fm, 2(3SC6F5-eq)),
3
d = ꢀ162.34 (t, 2Fp, 2(1SC6F5-ax), JFp–Fm = 20.69 Hz), d = ꢀ164.24
(m, 4Fm, 2(1SC6F5-ax)), isomer ‘‘2-up, 1-down”, d = ꢀ127.18 (d,
3
2Fo, 1SC6F5-eq-‘‘1-down”, JFo–Fm = 24.83 Hz), d = ꢀ130.24 (br s,
2Fo, ½(2SC6F5-eq-‘‘2-up”)), d = ꢀ131.08 (br s, 2Fo0, ½(2SC6F5-eq-
‘‘2-up”)), d = ꢀ131.74 (m, 2Fo, 1SC6F5-ax), d = ꢀ151.37 (t, 2Fp,
3
2SC6F5-eq-‘‘2-up”, JFp–Fm = 20.69 Hz), d = ꢀ151.72 (t, 1Fp, 1SC6F5-
3
eq-‘‘1-down”, JFp–Fm = 20.69 Hz), d = ꢀ158.03 (t, 1Fp, 1SC6F5-ax,
3JFp–Fm = 20.69 Hz), d = ꢀ160.67 (m, 2Fm, 1SC6F5-eq-‘‘1-down”),
3
d = ꢀ162.35 (t, 2Fm, ½(2SC6F5-eq-‘‘2-up”), JFm–F = 22.57 Hz),
d = ꢀ162.79 (m, 2Fm0, ½(2SC6F5-eq-‘‘2-up”)), d = ꢀ163.61 (m, 2Fm,
1SC6F5-ax). FAB+ꢀMS {m/z (%) [fragment]}: 1291 (2) [M+ꢀH],
1273 (4) [M+ꢀF], 1201 (1) [M+ꢀ(C6H4CH3)], 1093 (51)
[M+ꢀ(SC6F5)], 911 (2) [M+ꢀ(SC6F5)ꢀ2(C6H4CH3)], 893 (1)

M. Arroyo et al. / Polyhedron 28 (2009) 2625–2634
2633
3.8(1P(C6H4Cl-4)3)); isomer ‘‘2-up, 1-down”, d = 4.03 (s, 1.0P,
1P(C6H4Cl-4)3).19F NMR (C6D5CD3, RT), d(ppm): isomer ‘‘3-up”,
d = ꢀ129.25 (br s, 22.8Fo, 3.8(3SC6F5-eq)), d = ꢀ132.00 (d, 7.6Fo,
3.8(1SC6F5-ax), 3JFo–Fm = 24.45 Hz), d = ꢀ149.82 (t, 11.4Fp,
d = ꢀ129.26 (br s, 18Fo, 3(3SC6F5-eq)), d = ꢀ132.13 (d, 6Fo,
3
3(1SC6F5-ax), JFo–Fm = 19.18 Hz), d = ꢀ151.08 (t, 9Fp, 3(3SC6F5-eq),
3JFp–Fm = 20.69 Hz), d = ꢀ162.30 (br s, 18Fm, 3(3SC6F5-eq))
3
d = ꢀ162.46 (t, 3Fp, 3(1SC6F5-ax), JFp–Fm = 20.69 Hz), d = ꢀ164.50
3.8(3SC6F5-eq),
3JFp–Fm = 20.69 Hz),
d = ꢀ161.33
(t,
3.8Fp,
(m, 6Fm, 3(1SC6F5-ax)), isomer ‘‘2-up, 1-down”, d = ꢀ127.24 (d,
3
3
3.8(1SC6F5-ax), JFp–Fm = 20.69 Hz), d = ꢀ161.43 (br m, 22.8Fm,
2Fo, 1SC6F5-eq-‘‘1-down”, JFo–Fm = 21.82 Hz), d = ꢀ130.24 (br s,
3.8(3SC6F5-eq)), d = ꢀ163.74 (m, 7.6Fm, 3.8(1SC6F5-ax)), isomer
2Fo, ½(2SC6F5)-eq-‘‘2-up”), d = ꢀ131.20 (br s, 2Fo0, ½(2SC6F5)-eq-
‘‘2-up”), d = ꢀ131.80 (br s, 2Fo, 1SC6F5-ax), d = ꢀ151.26 (t, 1Fp,
3
‘‘2-up, 1-down”, d = ꢀ127.43 (d, 2Fo, 1SC6F5-eq-‘‘1-down”, JFo–
3
Fm = 23.32 Hz), d = ꢀ130.30 (br s, 2Fo, ½(2SC6F5)-eq-‘‘2-up”),
d = ꢀ131.12 (br s, 2Fo0, ½(2SC6F5)-eq-‘‘2-up”), d = ꢀ131.76 (m,
1SC6F5-eq-‘‘1-down”, JFp–Fm = 21.82 Hz), d = ꢀ151.44 (t, 2Fp,
3
2SC6F5-eq-‘‘2-up”, JFp–Fm = 20.69 Hz), d = ꢀ158.06 (t, 1Fp, 1SC6F5-
3
3
2Fo, 1SC6F5-ax), d = ꢀ149.60 (t, 1Fp, 1SC6F5-eq-‘‘1-down”, JFp–
ax, JFp–Fm = 20.69 Hz), d = ꢀ160.32 (m, 2Fm, 1SC6F5-eq-‘‘1-down”),
Fm = 20.31 Hz), d = ꢀ150.20 (t, 2Fp, 2SC6F5-eq-‘‘2-up”, 3JFp–
d = ꢀ162.62 (t, 2Fm, ½(2SC6F5)-eq-‘‘2-up”, JFm–F = 23.32 Hz),
3
3
Fm = 20.69 Hz), d = ꢀ157.06 (t, 1Fp, 1SC6F5-ax, JFp–Fm = 20.69 Hz),
d = ꢀ163.05 (br s, 2Fm0, ½(2SC6F5)-eq-‘‘2-up”), d = ꢀ163.84 (m,
2Fm, 1SC6F5-ax).
d = ꢀ159.36 (m, 2Fm, 1SC6F5-eq-‘‘1-down”), d = ꢀ161.78 (t, 2Fm,
3
½(2SC6F5)-eq-‘‘2-up”, JFm–F = 22.19 Hz), d = ꢀ162.23 (br m, 2Fm0,
½(2SC6F5)-eq-‘‘2-up”), d = ꢀ163.16 (m, 2Fm, 1SC6F5-ax). FAB+ꢀMS
{m/z (%) [fragment]}: 1352 (1) [M+], 1333 (1) [M+ꢀF], 1153 (100)
[M+ꢀ(SC6F5)], 1241 (1) [M+ꢀ(C6H4Cl)], 986 (2) [M+ꢀ(SC6F5)
ꢀ(C6F5)], 953 (2) [M+ꢀ2(SC6F5)ꢀH], 364 (13) [P(C6H4Cl)3+], 253
(18) [P(C6H4Cl)2+].
4.7. X-ray diffraction data
X-ray diffraction data for complexes 1a–5a were measured on
single crystals at 296(1) K, using a Bruker P4 diffractometer [26].
Data were corrected for absorption effects on the basis of
w-scans
[Os(SC6F5)3(SC6F4(SC6F5)-2)] [12] 6 (0.06 g, 5%).
(1a–2a) or crystal faces indexation (3a–5a). Essential X-ray data
are given in Table 1, and details may be found in the deposited
CIF, along with full geometric parameters. The structures were
solved and refined using SHELXS97 and SHELXL97 software [27]. For
3a, Wilson’s statistics are in agreement with a non-centrosymmet-
ric space group, and systematic extinction expected for a 21 axis is
not observed, allowing to rule out space groups P2/n and P21/n. A
refinement in space group Pn including 654 measured Friedel pairs
(R1 = 0.037) indicated a degree of twinning by inversion for the
crystal. The fractional contribution of the inverted model was then
refined, converging to x = 0.72(1) and R1 = 0.025. For 5a, each CF3
groups of the phosphane ligand is disordered over two sites, by a
4.5. [Os(SC6F5)4(P(C6H4CF3-4)3)] 5
The procedure is analogous to that for 1: reflux time 7 h. Prod-
ucts 5 and 6. Starting quantities: pentafluorobenzenethiol (0.8 mL,
6.0 mmol), osmium tetraoxide (0.25 g, 1.0 mmol), P(C6H4CF3-4)3
(1.00 g, 2.15 mmol). Slow evaporation of the eluent affords brown
crystals of 5 and green crystals of 6. Analyses and yields are as
follow:
[Os(SC6F5)4(P(C6H4CF3-4)3)] 5. Brown (0.13 g, 9%). Anal. Calc. for
C45H12F29OsPS4ꢁOH2: C, 36.74; H, 0.96; S, 8.72. Found: C, 36.49; H,
0.99; S, 8.73%. Mp: 166 °C, decomposes. IR (KBr, cmꢀ1): mthiolate
1512(vs), 1493(vs), 1090(vs), 983(vs), 856(s); mphosphane 1398(s),
1325(vs), 1177(s), 1135(s), 1063(vs), 1017(s), 839(s), 707(w),
600(w). 31P{1H} NMR (CDCl3, RT), d(ppm): isomer ‘‘3-up”, d = 8.52
(s, 4.4P, 4.4(1P(C6H4CF3-4)3)); isomer ‘‘2-up, 1-down”, d = 6.08 (s,
1.0P, 1P(C6H4CF3-4)3). 19F NMR (C6D5CD3, RT), d(ppm): isomer
‘‘3-up”, d = ꢀ63.98 (s, 39.6F, 4.4(1P(C6H4CF3-4)3)), d = ꢀ129.19 (br
s, 26.4Fo, 4.4(3SC6F5-eq)), d = ꢀ131.88 (d, 8.8Fo, 4.4(1SC6F5-ax),
rotation of ca. 60° about the C–CF3
r-bond. Site occupation factors
for disordered F atoms were fixed to 1/2. In order to get a sensible
geometry, C–F bond lengths were restrained to 1.31(1) Å and F. . .F
separations within each disordered part were restrained to
2.09(2) Å. For disordered F atoms in each CF3 group, Uij displace-
ment parameters were restrained to be similar with standard devi-
ation of 0.04 Å2, and to approximate to isotropic behavior. Complex
5a crystallizes as a monohydrate, the lattice water molecule being
disordered over two sites with occupancies 1/2. Drawings of Figs. 1
and 2 were made using the Mercury program [22].
3JFo–Fm = 22.83 Hz), d = ꢀ149.15 (t, 13.2Fp, 4.4(3SC6F5-eq), JFp–
3
Fm = 20.54 Hz), d = ꢀ160.73 (t, 4.4Fp, 4.4(1SC6F5-ax), 3JFp–
Fm = 20.65 Hz), d = ꢀ161.07 (br s, 26.4Fm, 4.4(3SC6F5-eq)),
d = ꢀ163.40 (m, 8.8Fm, 4.4(1SC6F5-ax)), isomer ‘‘2-up, 1-down”,
d = ꢀ64.01 (s, 3F, 1P(C6H4CF3-4)3), d = ꢀ64.15 (s, 6F, 1P(C6H4CF3-
Supplementary data
3
4)3), d = ꢀ127.51 (d, 2Fo, 1SC6F5-eq-‘‘1-down”, JFo–Fm = 22.68 Hz),
CCDC 716480, 716481, 716482, 716483, 716484 contains the
supplementary crystallographic data for 1a–5a. These data can
be obtained free of charge via http://www.ccdc.cam.ac.uk/conts/
retrieving.html, or from the Cambridge Crystallographic Data Cen-
tre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-
033; or e-mail: deposit@ccdc.cam.ac.uk.
d = ꢀ130.23 (br s, 2Fo, ½(2SC6F5)-eq-‘‘2-up”), d = ꢀ131.08 (br s,
2Fo0, ½(2SC6F5)-eq-‘‘2-up”), d = ꢀ131.71 (m, 2Fo, 1SC6F5-ax),
3
d = ꢀ148.55 (t, 1Fp, 1SC6F5-eq-‘‘1-down”, JFp–Fm = 20.99 Hz),
d = ꢀ149.51 (t, 2Fp, 2SC6F5-eq-‘‘2-up”, 3JFp–Fm = 20.20 Hz),
3
d = ꢀ156.42 (t, 1Fp, 1SC6F5-ax, JFp–Fm = 20.73 Hz), d = ꢀ158.85 (m,
2Fm, 1SC6F5-eq-‘‘1-down”), d = ꢀ161.42 (t, 2Fm, ½(2SC6F5)-eq-‘‘2-
3
up”, JFm–F = 22.34 Hz), d = ꢀ161.86 (br s, 2Fm0, ½(2SC6F5)-eq-‘‘2-
up”), d = ꢀ162.86 (m, 2Fm, 1SC6F5-ax). FAB+ꢀMS {m/z (%)
[fragment]}: 1453 (2) [M+ꢀH], 1435 (1) [M+ꢀF], 1255 (100)
[M+ꢀ(SC6F5)], 1088 (3) [M+ꢀ(SC6F5)ꢀ(C6F5)], 1055 (3) [M+
ꢀ2(SC6F5)ꢀH], 466 (35) [P(C6H4CF3)3+], 321 (13) [P(C6H4CF3)2+].
[Os(SC6F5)3(SC6F4(SC6F5)-2)] [12] 6. Green (0.28 g, 24%).
Acknowledgments
We are grateful to CONACYT (27915E) and VIEP (ARCS-NAT-08-
G) for financial support. SB acknowledges BUAP for the use of dif-
fraction facilities.
4.6. [Os(SC6F5)4(P(C6H5)3)] 7
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