Synthesis, characterization and hydrolysis of osmium tetraphosphorus complexes

Article abstract of DOI:10.1002/ejic.200900884

The reaction of [CpOs(PPh₃)₂Cl] (1) with one equivalent of white phosphorus in the presence of AgOTf (OTf = triflate, OSO₂CF₃) as chloride scavenger affords the stable metal complex [CpOs(PPh₃)_2<

Full text of DOI:10.1002/ejic.200900884

FULL PAPER
DOI: 10.1002/ejic.200900884
Synthesis, Characterization and Hydrolysis of Osmium Tetraphosphorus
Complexes
Maria Caporali,[a] Massimo Di Vaira,[b] Maurizio Peruzzini,*[a] Stefano Seniori Costantini,[b]
Piero Stoppioni,*[b] and Fabrizio Zanobini[a]
Keywords: Phosphorus / Coordination / Hydrolysis / Cyclopentadienyl ligands / Osmium
The reaction of [CpOs(PPh3)2Cl] (1) with one equivalent of
white phosphorus in the presence of AgOTf (OTf = triflate,
OSO2CF3) as chloride scavenger affords the stable metal
complex [CpOs(PPh3)2(η1-P4)]OTf (2), which contains the tet-
rahedral P4 η1-bound to the CpOs(PPh3)2 metal fragment.
Addition of [CpRu(PPh3)2(OTf)] to 2 yields the heterobimetal-
lic species [{CpRu(PPh3)2}{CpOs(PPh3)2}(µ,η1:1-P4)](OTf)2 (3),
in which the tetrahedral P4 is bound to two different metal
fragments through two phosphorus atoms. The compounds
have been characterized by elemental analysis, IR and NMR
spectroscopy, and their crystal structures have been deter-
mined by X-ray diffraction. The coordinated P4, at variance
with the free ligand, reacts with an excess amount of water
in thf under mild conditions to yield several products, most
of which have been characterized.
taining organophosphorus derivatives from white phospho-
rus through the mild and controllable activation of the co-
ordinated intact molecule. The results we have obtained in
this field are particularly intriguing, as we found that the
P4 molecule in the monometallic [CpRu(PPh3)2(η1-P4)]Y (Y
Introduction
In recent years, the reactivity of white phosphorus, P4,
towards different transition metal fragments has been
widely investigated.[1–5] The efforts of several research
groups in this field have led to the synthesis of an amazing
variety of transition metal complexes containing Pn units
originating from either the degradation of white phospho-
rus or from the recombination of smaller fragments into
polyatomic aggregates.[6,7] Indeed, while the range of Px
topologies which may be generated from P4 is enormous,
the number of coordination complexes featuring the intact
cage molecule as a ligand was, until a few years ago, limited
to very few examples of species thermally unstable and/or
difficult to handle.[8–11] Accordingly, the reactivity of the
coordinated molecule has been scarcely investigated. In
contrast to this general belief, we have found recently that
16-electron d7-metal complexes of rhenium,[12] iron[13] and
ruthenium[13–15] may coordinate the intact P4 molecule to
readily form mono- and bimetallic compounds in good
yield. The high stability and relatively good availability of
these complexes have allowed to investigate the reactivity
of the coordinated molecule towards a variety of different
organic and inorganic reagents. Such a topic deserves par-
ticular interest in view of the attractive possibility of ob-
= PF6, OTf)[14] (4) and bimetallic [{CpRu(PPh3)2}2(µ,η1:1
-
[15]
P4)](OTf)2
(5) complexes readily undergoes dispropor-
tionation with water under mild conditions. Detailed in-
vestigations of the hydrolysis have outlined some points of
great interest. Monometallic compound 4 yields phosphane
and oxygenated phosphorus compounds;[14] fine tuning the
properties of the metal fragment plays an important role in
determining the reactivity of the coordinated P4 tetrahe-
dron. For example, the structurally related [Cp*Ru(PPh3)2-
(η1-P4)]+ (Cp* = pentamethylcyclopentadienyl) does not
undergo hydrolysis under the same conditions.[13] The hy-
drolysis of the doubly metallated P4 in 5 is even more intri-
guing, as the products are strongly affected by the ratio of
complex and water. Thus, diphosphane P2H4,[15] 1-hydroxy-
triphosphane PH(OH)PHPH2[16] and 1,1,4-tris(hydroxy)tet-
raphosphane P(OH)2PHPHPH(OH)[17] form by the reac-
tion of 5 with different amounts of water. Such molecules,
which are either quite unstable (P2H4[18]) or unknown as
free molecules,[19] are highly stabilized through coordina-
tion to two ruthenium fragments.
The above results have clearly highlighted that the coor-
dination of the intact P4 molecule may be accomplished in
the presence of metal fragments with proper coordinating
properties. However, these have been, up to now, exploited
only for a limited number of 16-electron fragments, while
the activation of the coordinated molecule has been ob-
tained for an even more restricted number of complexes. To
[a] ICCOM CNR,
Via Madonna del Piano 10, 50019, Sesto Fiorentino, Firenze,
Italy
[b] Dipartimento di Chimica, Università di Firenze,
Via della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy
Fax: +39-0554573385
E-mail: mperuzzini@iccom.cnr.it
piero.stoppioni@unifi.it
152
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Hydrolysis of Osmium Tetraphosphorus Complexes
investigate further this field and, particularly, to address the
possible role played by the transition metal in driving the
hydrolysis of coordinated P4, we have now considered the
chemistry of P4 in the presence of the related CpOs(PPh3)2
fragment. Here we report on the synthesis of the highly
stable monometallic [CpOs(PPh3)2(η1-P4)]OTf (2) and het-
erobimetallic [{CpRu(PPh3)2}{CpOs(PPh3)2}(µ,η1:1-P4)]-
(OTf)2 (3). In thf at room temperature, these complexes
readily react with an excess amount of water to yield several
products, most of which have been isolated and charac-
terized. The crystal structures of 2 and 3, which are the first
examples of osmium complexes coordinating white phos-
phorus, have been determined by X-ray diffraction.
Results and Discussion
Scheme 1.
The reaction of [CpOs(PPh3)2Cl] (1) in a 1:1 thf/CH2Cl2
mixture with one equivalent of P4 in the presence of silver
triflate as chloride scavenger leads to the precipitation of the cage not involved in the coordination occurs at higher
AgCl and affords complex [CpOs(PPh3)2(η1-P4)]OTf (2), field (–462.76 ppm) with a coordination chemical shift
which can be isolated as orange microcrystals after workup. (∆δPF = 63.22 ppm) comparable to that observed for diru-
The addition of one equivalent of [CpRu(PPh3)2(OTf)] in thenium compound 5.[15] The two phosphorus atoms bound
CH2Cl2 to a solution of 2 in thf/CH2Cl2 mixture yields the to the metal fragments undergo higher downfield shifts with
heterobimetallic compound [{CpRu(PPh3)2}{CpOs(PPh3)2}- that of PM being more enhanced (∆δPM = 247.81 ppm) than
(µ,η1:1-P4)](OTf)2 (3) as red microcrystals. Both com- that of PF (∆δPF = 211.06 ppm).
pounds, which are obtained in good yield, are stable under
The structure of 2 consists of [CpOs(PPh3)2(η1-P4)]+
an inert atmosphere and soluble in common organic sol- complex cations and triflate anions. The compound is iso-
vents (Scheme 1). The 31P{1H} NMR spectra of both 2 and morphous with the [CpRu(PPh3)2(P4)](PF6) ruthenium ana-
3 (CDCl3, r.t.) clearly show that the P4 molecule is firmly logue 4,[14] irrespective of the different nature of the anions
coordinated to the metal(s) also in solution. No high-field in the two compounds. The geometry of the osmium cation
resonance attributable to P4 dissociation is observed in in 2 (Figure 1) is closely similar to that of the ruthenium
solution at room temperature. Compound 2 exhibits an complex, which may be mostly attributed to the similarity
A2FM3 spin system in which A denotes the two equivalent in the atomic radii of the two metals. The Os–P(PPh3) dis-
triphenylphosphane phosphorus atoms, F is the atom tances (Table 1) are slightly shorter, by 0.024 Å on average,
bound to the metal and M stands for the three atoms of than the corresponding distances in the ruthenium cation,
the tetraphosphorus tetrahedron not involved in coordina- and the Os–P(P4) distance, 2.263(1) Å, almost matches the
tion (see Scheme 1 for labels). The phosphane ligands yield Ru–P(P4) one [2.269(2) Å]. The values of the P–P distances
resonances in the range expected for cationic osmium half- in the P4 cage of 2 are, overall, slightly larger than those
sandwich compounds.[20] The four phosphorus atoms of the found for the ruthenium complex 4: in particular, the mean
coordinated tetraphosphorus ligand form the FM3 part of value of the three P–P distances formed by the coordinating
the spectrum. These resonances are shifted downfield with phosphorus atom and that of the three P–P distances be-
respect to the free P4 molecule (∆δPF = 149.57, ∆δPM
=
tween the distal P atoms of the cage in 2 are larger than the
48.37 ppm), and this shift, as found for the analogous ru- corresponding mean values for the ruthenium complex by
thenium [CpRu(PPh3)2(η1-P4)]Y derivative 4,[14] is particu- 0.008 Å and 0.025 Å, respectively. Such differences may be
larly enhanced for the atom bound to the metal centre.
considered to result from effects of apparent bond shorten-
Complex 3 yields a first-order A2B2FMQ2, where A and ing because of thermal motion, significantly affecting the
B are the triphenylphosphane phosphorus atoms of the P4 dangling group in the room-temperature structure of the
CpOs(PPh3)2 and CpRu(PPh3)2 fragments, respectively, F ruthenium derivative. Indeed, in the structure of 2 refined
and M are the P4 atoms bound to osmium and ruthenium, from room temperature data,[21] the mean values of the
respectively, and Q denotes the two atoms of the tetraphos- same groups of P–P distances are found to be in line, within
phorus tetrahedron not involved in the coordination (see 0.001 Å, with those of the ruthenium compound. The struc-
Scheme 1 for labels). Both the chemical shifts and the cou- ture of compound 3 comprises bimetallic cations, triflate
pling constants of the phosphane ligands show values in the anions and solvate chloroform molecules, some of which
range expected for cationic osmium[20] and ruthenium[14,15] are in highly disordered arrangement. Also the cation (Fig-
half-sandwich compounds. The signals of the coordinated ure 2), which possesses apparent twofold rotational sym-
P4 are shifted downfield with respect to the free molecule. metry, the twofold axis passing through the P–P bond of
The resonance ascribable to the two phosphorus atoms of the bridging phosphorus atoms and through the opposite
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M. Peruzzini, P. Stoppioni et al.
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bond in the cage, is affected by orientational disorder, each Table 1. Selected bond lengths [Å] and angles [°] for 2.[a]
metal site (M) having 50% Ru and 50% Os character. How-
Os–P1
Os–P2
Os–P3
P3–P4
P3–P5
P1–Os–P2
P1–Os–P3
2.345(1)
2.327(1)
2.263(1)
2.146(1)
2.167(1)
103.56(3)
93.73(3)
P3–P6
P4–P5
P4–P6
P5–P6
Os–C(Cp)
P2–Os–P3
2.151(1)
2.198(2)
2.214(2)
2.231(2)
2.215–2.263
91.31(3)
ever, this type of disorder is expected to have minor conse-
quences on the values of derived structural parameters, be-
cause of the similarity in the values of the atomic radii of
Ru and Os, which is consistent with the above results of the
comparison between the monometallic P4 derivatives. The
(metal-mediated) geometry of the cation in 3 (Table 2)
closely corresponds to that of the diruthenium cation in the
structure of the previously reported [{CpRu(PPh3)2}2-
(µ,η1:1-P4)](OTf)2 (5).[15] The M–P(PPh3) distances in 3 are
shorter, by 0.018 Å on average, than those of the diruthe-
nium complex, and the M–P(P4) bond length in 3 is only
0.004 Å smaller than the mean of the two values in the
other compound. There is also close agreement, within
0.002 Å, between the mean values of the six P–P distances
in the P4 cages of the two compounds (effects of thermal
motion should be smaller for the cage in bridging position
than for the monodentate one; moreover, the data sets of
both bimetallic compounds were collected at low tempera-
ture). In detail, a feature already noticed for the structure
of the diruthenium complex is found also for 3: the P–P
bond formed by the bridging phosphorus atoms is the
shortest among all bonds in the cage, whereas the opposite
bond is the longest one. Remarkably, the –26.9(6)° M–P3–
P3Ј–MЈ torsion angle in 3 is quite close to the –27.4(6)°
value found for the diruthenium cation, in spite of the dif-
ferent packing and local symmetries of the cations in the
two structures. This suggests that the overall conformation
of the bimetallic cation is primarily dictated by the steric
requirements of the bulky triphenylphosphane ligands.
[a] 150 K data.
Figure 2. A view of the cation in the structure of 3 with 30% prob-
ability ellipsoids. The metal sites M have 50% Ru and Os occupan-
cies. Primed atoms are related to the corresponding unprimed ones
by a twofold axis bisecting the P3–P3Ј and P4–P4Ј bonds. Hydro-
gen atoms are omitted for clarity.
Table 2. Selected bond lengths [Å] and angles [°] for 3.[a]
M–P1
M–P2
2.353(1)
2.346(1)
2.285(1)
2.168(3)
99.49(5)
92.51(5)
P3–P4
P3–P4
P4–P4
M–C(Cp)
P2–M–P3
M–P3–P3[b]
2.197(2)
2.189(2)
2.224(4)
2.226–2.249
98.76(5)
‡
‡
M–P3
P3–P3[b]
P1–M–P2
P1–M–P3
158.41(4)
[a] The metal site has 50% Ru and 50% Os occupancy. [b] Sym-
metry operation: 1 – x, y, 1/2 – z.
3 after workup show the presence of a mixture of several
compounds, most of which have been identified and whose
percentages were estimated with respect to the four phos-
phorus atoms in 2 and 3 by careful integration of the corre-
sponding resonances.
Compound 2 is completely hydrolyzed within one day in
the presence of 100 equiv. of water. The hydrolysis of 2 is
significantly slowed down with respect to that of the ruthe-
nium derivative 4, which is completely transformed within
a few hours. The products include free hypophosphorous
(20%) and phosphorous (55%) acids, and the cationic spe-
cies of compounds 6 and 8, [CpOs(PPh3)2(PH3)]+ (55%)
Figure 1. A view of the cation in the structure of 2 with 50% prob-
ability ellipsoids. Hydrogen atoms are omitted for clarity.
When a solution of 2 or 3 in thf was treated with an and [CpOs(PPh3)2{P(OH)3}]+ (22%), respectively. Further
excess amount of water, hydrolysis of the P4 ligand occurred products, for which no structure can be assigned by NMR
at room temperature. Reactions carried out on different spectroscopic analysis, are also formed. The oxyacids were
batches are reproducible, both with respect to the amount identified by comparison of the 31P NMR spectra of the
and nature of the products obtained. The 31P{1H} NMR hydrolyzed mixture with those of the pure specimen in the
spectra of the solids obtained from the hydrolysis of 2 and same solvent. Cations 6 and 8 were identified by compari-
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Hydrolysis of Osmium Tetraphosphorus Complexes
son of the NMR (1H and 31P) spectroscopic data of the nation geometry is assigned to the present osmium deriva-
mixture with those of the pure compounds, which have been tives. Compounds 6, 7 and 8, in addition to their essential
synthesized and characterized by elemental analysis and value in assessing the nature of the products from the hy-
NMR spectroscopy separately (see below). Thus, the hy- drolysis of 2 and 3, have an intrinsic interest. Indeed, com-
drolysis of 2 yields substantially the same products that pound 6 adds to the rare examples of metal–PH3 deriva-
have been observed from the reaction of the analogous ru- tives,[23] and the formation of compounds 7 and 8 provides
thenium derivative 4;[14] the main difference consists in the true examples of hypo- and phosphorous acid isomeriza-
formation of a small amount of complex 8, containing the tion, which has been observed only for the analogous ruthe-
phosphorous acid, which was not observed in the hydrolysis nium derivatives.[22]
of 4.
The hydrolysis of [{CpRu(PPh3)2}2(µ,η1:1-P4)](OTf)2 (5),
Compounds [CpOs(PPh3)2(PH3)]CF3SO3 (6) and [CpOs- in which two phosphorus atoms of the cage bridge two
(PPh3)2{PR(OH)2}]CF3SO3 [R = H, (7), OH (8)] are ob- CpRu(PPh3)2 moieties, had been studied in detail.[15–17] The
tained in high yield by adding either the stoichiometric reaction follows several routes depending on the reaction
amount of the acid (H3PO2 or H3PO3) or by bubbling gas- conditions, particularly on the amount of added water, and
eous PH3 through a solution of [CpOs(PPh3)2Cl] in a a mixture of products is usually obtained. By adding
CH2Cl2/thf mixture in the presence of the stoichiometric 500 equiv. of water to 5, only two compounds were ob-
amount of thallium triflate to scavenge the chloride ligand. tained: phosphorous acid and 1-hydroxytriphosphane. The
The white complexes are stable under an inert atmosphere latter molecule is stabilized through coordination to two
and are soluble in common organic solvents.
equivalent ruthenium fragments.[16] Therefore, the selectiv-
The 31P{1H} NMR spectrum of 6 exhibits an A2F ity of this reaction suggested that the hydrolysis of 3 should
pattern in which the lower field doublet is assigned to the be repeated under the same conditions. In keeping with our
phosphorus atoms of triphenylphosphane ligands (PA) and expectation, addition of 500 equiv. of water to a solution of
the higher field triplet (δ = –152.22) to the phosphorus 3 completely hydrolyzes the dimer within 1 h. The 31P{1H}
atom of the coordinated phosphane (PF). The triplet of the NMR spectrum of the solid obtained from the hydrolysis
phosphane is resolved in a quartet of triplets in the 31P-1H shows the presence of several compounds, including free
coupled spectrum, as expected for a P-coordinated PH3. phosphorous acid and the cations [CpM(PPh3)2(PH3)]+ and
1
The observed value of J(PF,H) = 368.5 Hz is in the range [CpM(PPh3)2{PR(OH)2}]+ (M = Ru, Os; R = H, OH),
of those found for coordinated PH3.[14] The hydrogen atoms which were identified by comparison of their NMR (1H and
1
directly bound to phosphorus show in the H NMR spec- 31P) spectroscopic data with those of the pure compounds
trum a doublet of triplets (δ =4.38 ppm), characterized by previously described. Remarkably, and at variance with the
1
3
the above strong J(H,PF) coupling and a weak J(H,PA) homo bimetallic ruthenium derivative, no polyphosphorus
one (4.0 Hz). The elemental analysis and the NMR spectro- compound is formed, and only those mononuclear species
scopic data allow to conclude unambiguously that PH3 is that are considered as the thermodynamic sinks along the
bound to the CpOs(PPh3)2 fragment.
degradation pathway of the heterobimetallic complex are
The 31P{1H} NMR spectra of 7 and 8 consist of A2F obtained. The hydrolysis performed with a smaller amount
spin systems in which the lower field triplet is assigned to (100 equiv.) of water reaches completion much more slowly
the phosphorus atom (PF) of the hypophosphorous or (one day) still substantially yielding single phosphorus spe-
phosphorous acid and the higher field doublet to the tri- cies.
phenylphosphane atoms (PA). The 31P resonance of the co-
ordinated hypophosphorous acid occurs at a lower field
than that of the phosphorous acid. The triplet of hypophos-
Conclusions
phorous derivative 7 is doubled in the 31P-1H coupled spec-
trum, showing that only one hydrogen is bound to the P
[CpOs(PPh3)2]+, generated in situ by chloride removal
1
atom; the observed value of J(P,H) = 425.5 Hz is similar from [CpOs(PPh3)2Cl], is a suitable synthon for the prepa-
to that found for tetracoordinate P–H systems.[22] The hy- ration of osmium complexes containing tetraphosphorus as
drogen atom directly bound to phosphorus yields in the 1H a ligand. The monometallic [CpOs(PPh3)2(η1-P4)]OTf and
NMR spectrum a doublet of triplets (δ = 8.84 ppm), char- the heterobimetallic [{CpRu(PPh3)2}{CpOs(PPh3)2}(µ,η1:1
-
acterized by the above strong 1J(H,PF) coupling and a weak P4)](OTf)2 were prepared and characterized by elemental
3J(H,PA) one (3 Hz). On the other hand, no P–H coupling analysis, IR, NMR spectroscopy and X-ray crystallography.
is observed for the coordinated H3PO3, clearly showing that The latter technique allowed to collect important metrical
no hydrogen atom is bound to the PF phosphorus in that parameters for this class of compounds. Remarkably,
case. The NMR spectroscopic data for complexes 7 and 8 double metallation of the P4 with different metal fragments
parallel those of the ruthenium analogues [CpRu(PPh3)2- does not result in any significant deformation with respect
{PR(OH)2}]OTf (R = H, OH), which have been found, by to the geometry of either the free ligand or the homobime-
X ray analysis, to contain the unstable hydroxyphosphane tallic diruthenium compound.
tautomers of the hypophosphorous [HP(OH)2] and phos-
Both compounds react with an excess amount of water
phorous [P(OH)3] acids stabilized by coordination through to undergo complete hydrolysis of the P4 cage. The hydroly-
their P atom to the metal.[22] Accordingly, the same coordi- sis products of the monometallic compound substantially
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M. Peruzzini, P. Stoppioni et al.
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sulting brick-red solution was stirred for 30 min at room tempera-
ture, and then the solvent was removed under vacuum. The solid
was recrystallized from CHCl3/n-hexane. Yield 450 mg (80%).
C84H70F6O6OsP8RuS2 (1892.5): calcd. C 53.30, H 3.73, P 13.09;
found C 53.20, H 3.80, P 12.90. 1H NMR (400.13 MHz; (CD3)
2CO, 21 °C): δ = 7.60–6.90 (m, 60 H, C6H5), 5.11 (s, 5 H, C5H5),
4.97 (s, 5 H, C5H5) ppm. 31P{1H} NMR [161.89 MHz, (CD3)2CO,
21 °C]: A2B2FMQ2 spin system, δ = 38.24 [d, 2J(PB,PM) = 51.3 Hz,
2 P, PB], –5.23 [d, 2J(PA,PF) = 31.3 Hz, 2 P, PA], –278.19 [dtt,
parallel those obtained from the ruthenium analogue, while
the products obtained from the hydrolysis of the heterobi-
metallic OsRu complex encompass only single phosphorus
species, in this case diverging from the behaviour of the
RuRu analogue. In fact, at variance with the ruthenium
homobimetallic derivative, the hydrolysis of the OsRu dimer
is driven to single P compounds that are at the end of the
P4 hydrolytic degradation.
1
1J(PM,PQ) = 145.8, J(PM,PF) = 229.0 Hz, 1 P, PM], –314.94 [dtt,
Studies are in progress to further expand the reactivity
of coordinated P4 and to better understand the mechanism 1J(PF,PQ) = 163.0 Hz, 1 P, PF], –462.78 (dd, PQ)ppm.
of its hydrolytic cleavage.
Hydrolysis of 2: Water (40 mmol) was added to compound 2
(420 mg, 0.40 mmol) in thf (60 cm3), and the system was stirred at
room temperature for 1 d; the orange colour of the solution
changed to yellow. Mass spectra of the gas phase did not show any
volatile hydrolysis products. The solvent was then removed under
reduced pressure to yield a yellow solid whose spectrum in (CD3)2-
CO exhibited resonances assigned to H3PO2, H3PO3, [CpRu(PPh3)2-
(PH3)]OTf and [CpRu(PPh3)2{P(OH)3}]OTf.
Experimental Section
All reactions and manipulations were performed under an atmo-
sphere of dry, oxygen-free argon. The solvents were purified ac-
cording to standard procedures.[24] 1H, 19F and 31P NMR spectra
were obtained with a Bruker Avance 400 plus spectrometer. 19F
and 31P chemical shifts are relative to external CFCl3 and to 85% Hydrolysis of 3: The reaction was carried out as for 2 by adding to
1
H3PO4, respectively. H chemical shifts are relative to tetramethyl-
silane as external reference and were calibrated against the residual
solvent resonance. Downfield values are reported as positive, cou-
pling constants are in Hertz. 19F NMR spectra of all compounds
yielded a singlet at –75.5 ppm for the triflate anion. Nujol mull
infrared spectra were obtained with a Perkin–Elmer Spectrum BX
FTIR spectrometer with samples between NaCl discs. Microanaly-
ses were carried out at the Microanalytical Laboratory of the De-
partment of Chemistry of the University of Florence. [CpRu(PPh3)2-
(OTf)] was prepared according to the literature.[25] Aqueous solu-
tions of H3PO2, H3PO3 (Aldrich), TlOTf and AgOTf (Strem Chem-
icals) were used as received.
3 (570 mg, 0.30 mmol) in thf (60 cm3) either 500 or 100 equiv. of
water.
[CpOs(PPh3)2(PH3)]CF3SO3 (6): Gaseous PH3 was gently bubbled
for 5 min through
a solution of [CpOs(PPh3)2Cl] (122 mg,
0.15 mmol) and AgOTf (38 mg, 0.15 mmol) in a mixture of thf
(15 cm3) and CH2Cl2 (15 cm3). The resulting slurry was stirred at
room temperature for 1 h; the solid was filtered off, and pale yellow
microcrystals were obtained by evaporating the solvent under re-
duced pressure. The solid was recrystallized from CH2Cl2/n-hexane.
Yield 120 mg (85%). C42H38F3O3OsP3S (962.9): calcd. C 52.38, H
3.98, P 9.65; found C 52.28, H 4.10, P 9.40. 1H NMR [400.13 MHz;
(CD3)2CO, 21 °C]: δ = 7.4–7.10, (m, 30 H, C6H5), 4.89 (s,%H,
C5H5), 4.38 [dt, 1J(H,PF) = 368.5, 3J(H,PA) = 4.0 Hz, 3 H, PH3]
ppm. 31P{1H} NMR [161.89 MHz, (CD3)2CO, 21 °C]: A2F spin
[CpOs(PPh3)2Cl] (1): The compound has been synthesized through
an improved procedure with respect to that previously described.[26]
Freshly cracked and distilled cyclopentadiene (2.7 cm3) was added
to [Os(PPh3)3Cl2][27] (0.530 mg, 0.50 mmol) in thf (25 cm3), and the
solution was refluxed for 2 h; in the meantime the green solution
became yellow. Half of the solvent was removed under reduced
pressure, and yellow microcrystals of 1 were obtained by adding
ethanol. The solid was recrystallized from a mixture of CH2Cl2/
ethanol (2:1). Yield 830 mg (80%). Both elemental analysis and
NMR spectroscopic data agree with those given in the literature.[26]
2
system, δ = –1.69 [d, J(PA,PF) = 30.8 Hz, 2 P, PF], –152.22 (t, 1 P,
PF) ppm.
[CpOs(PPh3)2(PR(OH)2)]CF3SO3 [R = H (7); R = OH (8)]: The
two compounds were obtained by the same procedure. To a suspen-
sion of [CpOs(PPh3)2Cl] (1) (122 mg, 0.15 mmol) and AgOTf
(38 mg, 0.15 mmol) in a mixture of thf (15 cm3) and CH2Cl2
(15 cm3) was added at room temperature whilst stirring one equiva-
lent of either H3PO2 or H3PO3. The resulting slurry was stirred for
[CpOs(PPh3)2(η1-P4)](CF3SO3) (2): AgOTf (128 mg, 0.50 mmol) 2 h at room temperature, and in the meantime the yellow colour
was added to solution of [CpOs(PPh3)2Cl] (1) (407 mg, faded. The solid was filtered off, and light yellow microcrystals of
a
0.50 mmol) dissolved in a mixture of CH2Cl2 (30 cm3) and thf
(30 cm3); the resulting slurry was stirred for 2 h at room tempera-
ture and filtered. The filtrate was added to P4 (80 mg, 0.70 mmol)
dissolved in thf (20 cm3); the resulting solution was stirred 1 h at
room temperature, and then the solvent was removed under vac-
uum. The orange solid was washed with toluene (2ϫ10 cm3), pen-
tane (2ϫ10 cm3) and dried. Yield 420 mg (85%). The complex may
[CpOs(PPh3)2{PR(OH)2}]OTf (R = H, OH) were obtained by sol-
vent evaporation under reduced pressure. The solid was recrys-
tallized from (CH3)2CO/n-hexane. Yield 80%. 7: C42H38F3O5OsP3S
(994.9): calcd. C 50.70, H 3.85, P 9.34; found C 50.54, H 3.89, P
9.10. FTIR: ν
= (PH) 2302 (s) cm–1. 1H NMR [400.13 MHz;
˜
max
(CD3)2CO, 21 °C]: δ = 8.84 [dt, 1J(H,PF) = 425.0, 3J(H,PA) =
3.0 Hz, 1 H, HP(OH)2], 7.50–7.10 (m, 30 H, C6H5), 4.89 (s, 5 H,
be recrystallized from CHCl3/n-hexane. C42H35F3O3OsP6S C5H5) ppm. 31P{1H} NMR [161.89 MHz, (CD3)2CO, 21 °C]: A2F
2
(1052.8): calcd. C 47.91, H 3.35, P 17.65; found C 47.80, H 3.50,
spin system, δ = –0.25 [d, J(PA,PF) = 32.1 Hz, 2 P, PA], 87.37 (t,
1 P, PF) ppm. 8: C42H38F3O6OsP3S (1010.9): calcd. C 49.90, H 3.79,
1
P 17.50. H NMR (400.13 MHz. CDCl3, 21 °C): δ = 7.60–6.90 (m,
30 H, C6H5), 4.83 (s, 5 H, C5H5) ppm. 31P{1H} NMR (161.89, P 9.19; found C 49.54, H 3.89, P 9.05. 1H NMR [400.13 MHz;
CDCl3, 21 °C): A2FM3 spin system, δ = –5.94 (d, 2J(PA,PF) =
38.4 Hz, 2 P, PA), –376.43 (tq, 1J(PF,PM) = 238.0 Hz, 1 P, PF),
–477.63 (d, 3 P, PM) ppm.
(CD3)2CO, 21 °C]: δ = 7.50–7.00 (m, 30 H, C6H5), 4.92 (s, 5 H,
C5H5) ppm. 31P{1H} NMR [161.89, (CD3)2CO, 21 °C]: A2F spin
system, δ = 84.28 [t, 2J(PF,PA) = 37.5 Hz, 1 P, PF], –2.05 (d, 2 P,
PA) ppm.
[{CpRu(PPh3)2}{CpOs(PPh3)2}(µ,η1:1-P4)](CF3SO3)2 (3): A solu-
tion of [CpRu(PPh3)2OTf] (252 mg, 0.3 mmol) in CH2Cl2 (8 cm3)
was added to [CpOs(PPh3)2(η1-P4)]OTf (2) (316 mg, 0.3 mmol) dis-
solved in a mixture of CH2Cl2 (25 cm3) and thf (25 cm3). The re-
Crystallographic Data Collection and Refinement Procedures: Data
collections were performed with an Oxford Diffraction Xcalibur 3
CCD diffractometer, with graphite-monochromated Mo-Kα radia-
156
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© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2010, 152–158

Hydrolysis of Osmium Tetraphosphorus Complexes
tion for 2, and with an Oxford Diffraction Xcalibur PX Ultra CCD
diffractometer equipped with Enhance Ultra optics, by using Cu-
Kα radiation for 3. For 2, data collections were performed both at
150 K and, for comparison, at room temperature; results for the
latter are summarized in a CIF file.[21] Absorption corrections were
performed by the ABSPACK multiscan procedure of the CrysAlis
data reduction package.[28] The structures were solved by direct
methods with SIR2004,[29] and the structural models were com-
pleted and refined with SHELXL97.[30] Since the bimetallic cation
in 3 possesses twofold rotational symmetry, the metal site was as-
signed 50% Ru and 50% Os populations. In the final refinement
cycles on both structural models, all non-hydrogen atoms (includ-
ing those of the disordered solvent molecule in the structure of 3;
see below) were refined anisotropically, and the hydrogen atoms
were in calculated positions, riding, with UH = 1.2UCeq. One of the
chloroform solvate molecules in the structure of 3 was highly affec-
ted by disorder and was modelled as being distributed among three
distinct orientations within a confined volume, whose fractional
occupancy factors were refined with the restraint of overall unit
value. Geometrical restraints were applied in the course of the re-
finement on both solvate molecules and the anion in the structure
of 3 (Table 3). The highest peaks of residual density in the final
difference Fourier analysis of both structures were in the proximity
of the heavy atom positions or of the parts affected by disorder
and could not be assigned any chemical meaning. Programs used
in the crystallographic calculations included WinGX[31] and
ORTEP for graphics.[32]
Acknowledgments
Financial support by the Italian Ministero dell’Istruzione, dell’Uni-
versità e della Ricerca is gratefully acknowledged (PRIN2007).
This work has been carried out within the frame of COST AC-
TION CM0802 “PHOSCINET” of the European Community.
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2
3
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[21] Results of the refinement of the structure of 2 by using room
temperature data have been deposited as a CIF file: see the
Experimental Section.
Empirical formula
Mr
Crystal system
Space group
T [K]
a [Å]
b [Å]
c [Å]
C42H35F3O3OsP6S C88H74Cl12F6O6OsP8RuS2
1052.78
monoclinic
P21/c
2370.02
monoclinic
C2/c
150(2)
173(2)
11.3805(2)
14.8883(2)
24.0308(3)
94.423(1)
4059.6(1)
4
22.3510(3)
18.3381(2)
24.4186(3)
108.186(2)
9508.6(2)
4
β [°]
V [Å3]
Z
dcalcd. [gcm–3]
1.723
1.656
Absorption coefficient [mm–1] 3.483
9.092
F(000)
θ range [°]
2080
4720
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3.75–26.37
39587
8275
3.81–72.64
60084
9382
Reflections measured
Independent reflections
Observed reflections
[IϾ2σ(I)], Rint
No. of parameters/restraints
Final R indices [IϾ2σ(I)] R1,
wR2
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6810, 0.0323
505/0
7945, 0.0500
635/79
0.0248, 0.0656
0.0589, 0.1618
Final R indices (all data) R1,
wR2
0.0339, 0.0675
1.077
0.0679, 0.1715
1.025
GooF on F2
∆ρmax, ∆ρmin [eÅ–3]
2.507, –0.558
2.051, –0.962
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4221–4228.
CCDC-746584 (for 2 at 150 K), -746585 (for 2 at293 K) and
-746586 (for 3) contain the supplementary crystallographic data for
this paper. These data can be obtained free of charge from the
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
Eur. J. Inorg. Chem. 2010, 152–158
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
157

M. Peruzzini, P. Stoppioni et al.
FULL PAPER
[28] Oxford Diffraction, CrysAlis RED (version 171.32.29), 2006,
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Cascarano, L. De Caro, C. Giacovazzo, G. Polidori, R.
Received: October 19, 2009
Spagna, J. Appl. Crystallogr. 2005, 38, 381–388.
Published Online: November 25, 2009
158
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Eur. J. Inorg. Chem. 2010, 152–158