Synthesis, characterization, and dynamic behaviour of triosmium clusters containing the tridentate ligand {Ph2PCH2CH 2}2S (PSP)

Article abstract of DOI:10.1002/ejic.201201403

Reaction of [Os₃(CO)₁₁(NCMe)] with bis-diphenylphosphanylethylene sulfide, {Ph₂PCH₂CH ₂}₂S (PSP), leads to the formation of [Os ₃(CO)₁₁(PSP)] and [{Os₃(CO)₁₁} ₂(μ-PSP)] in good yield. Similarly, treatment of [Os ₃(CO)₁₀(NCMe)₂] with PSP affords the cluster [Os₃(CO)₁₀(μ-PSP)], in which the two phosphanes of the PSP ligand coordinate to different osmium atoms of the same triosmium unit. Reaction of [Os₃(CO)₁₁(PSP)] with [Os₃(CO) ₁₀(NCMe)₂] yields the compound 1,2-[{Os ₃(CO)₁₁}(μ₃-PSP){Os₃(CO) ₁₀}] in which the thioether moiety and one of the phosphane groups of the PSP ligand are coordinated equatorially to the {Os₃(CO) ₁₀} subunit. The cluster 1,2-[{Os₃(CO)₁₁} (μ₃-PSP){Os₃(CO)₁₀}] is also formed when [Os₃(CO)₁₁(PSP)] is oxidatively decarbonylated by reaction with trimethylamine N-oxide. The metastable cluster 1,2-[{Os ₃(CO)₁₁}(μ₃-PSP){Os₃(CO) ₁₀}] undergoes slow isomerisation at room temperature to form 1,1-[{Os₃(CO)₁₁}(μ₃-PSP){Os ₃(CO)₁₀}] in which the thioether and phosphane moieties coordinate in a chelating mode to one of the {Os₃(CO)₁₀} subunits with the thioether moiety in an axial position. The dynamic behaviour of these clusters has been investigated by variable-temperature ¹³C{¹H} and ¹³P{¹H} NMR spectroscopy. The solid-state structures of [{Os₃(CO) ₁₁}₂(μ-PSP)] and [Os₃(CO) ₁₀(μ-PSP)] are reported. New clusters coordinated by the tridentate ligand {Ph₂PCH₂CH₂}₂S have been synthesised and structurally characterised. A new example of a nondestructive rearrangement of a P,S-bridged triosmium cluster that involves a sulfur carbonyl exchange route is reported. Copyright

Full text of DOI:10.1002/ejic.201201403

FULL PAPER
DOI:10.1002/ejic.201201403
Synthesis, Characterization, and Dynamic Behaviour of
Triosmium Clusters Containing the Tridentate Ligand
{Ph2PCH2CH2}2S (PSP)
Roger Persson,[a] Marc J. Stchedroff,[a,b] Roberto Gobetto,[b]
Carl J. Carrano,[c] Michael G. Richmond,[d] Magda Monari,[e] and
Ebbe Nordlander*[a]
Keywords: Cluster compounds / Osmium / Tridentate ligands / P,S ligands / Isomerization
Reaction of [Os3(CO)11(NCMe)] with bis-diphenylphosphan-
ylethylene sulfide, {Ph2PCH2CH2}2S (PSP), leads to the for-
mation of [Os3(CO)11(PSP)] and [{Os3(CO)11}2(μ-PSP)] in
good yield. Similarly, treatment of [Os3(CO)10(NCMe)2] with
PSP affords the cluster [Os3(CO)10(μ-PSP)], in which the two
phosphanes of the PSP ligand coordinate to different osmium
when [Os3(CO)11(PSP)] is oxidatively decarbonylated by re-
action with trimethylamine N-oxide. The metastable cluster
1,2-[{Os3(CO)11}(μ3-PSP){Os3(CO)10}] undergoes slow iso-
merisation at room temperature to form 1,1-[{Os3(CO)11}(μ3-
PSP){Os3(CO)10}] in which the thioether and phosphane moi-
eties coordinate in a chelating mode to one of the {Os3-
(CO)10} subunits with the thioether moiety in an axial posi-
tion. The dynamic behaviour of these clusters has been in-
vestigated by variable-temperature 13C{1H} and 13P{1H}
NMR spectroscopy. The solid-state structures of [{Os3-
(CO)11}2(μ-PSP)] and [Os3(CO)10(μ-PSP)] are reported.
atoms of the same triosmium unit. Reaction of [Os3(CO)11
-
(PSP)] with [Os3(CO)10(NCMe)2] yields the compound 1,2-
[{Os3(CO)11}(μ3-PSP){Os3(CO)10}] in which the thioether moi-
ety and one of the phosphane groups of the PSP ligand are
coordinated equatorially to the {Os3(CO)10} subunit. The
cluster 1,2-[{Os3(CO)11}(μ3-PSP){Os3(CO)10}] is also formed
phosphane ligands in both poly- and mononuclear com-
plexes have also been detected.[10] However, less attention
has been paid to mixed-donor ligands. Multidentate phos-
phane–thiol or phosphane–thioether (P,S) ligands have
been the focus of considerable interest because they are in-
herently asymmetric and potentially hemilabile. Such li-
gands have been shown to be potentially useful in catalytic
alkylation, carbonylation and coupling reactions.[11,12] In-
vestigations into the interactions of P,S ligands with transi-
tion-metal carbonyl clusters remain scarce, with the notable
exception of the cluster chemistry of thienylphos-
phanes.[13,14]
Introduction
The coordination of multidentate phosphanes to metal
clusters has been thoroughly studied.[1–4] Smith,[3c,5,6]
Lewis,[2,7] Deeming,[8] Kabir[9] and their co-workers have in-
vestigated a number of diphosphane-substituted derivatives
of [Os3(CO)12] that involve the ligands Ph2P(CH2)nPPh2
(n = 1–5). Many studies have been carried out on the corre-
lation between the chain length of such phosphane ligands
and their coordination modes as well as the dynamics of
the clusters. Correlations between the chemical shifts of the
phosphorus nuclei and the chain lengths of polydentate
We have studied the coordination chemistry of some
phosphane–thiother ligands with osmium clusters.[15] In our
study of the ligand Ph2PCH2CH2SMe (PS) with regard to
triosmium clusters, we found that (i) the thioether moiety
of the P,S ligand can only coordinate to a metal centre when
the phosphane is already coordinated and (ii) the (kinet-
ically favoured) cluster 1,2-[Os3(CO)10(μ-PS)] slowly con-
verts to the thermodynamically favoured cluster 1,1-
[Os3(CO)10(PS)] in solution.[15a] Although many mononu-
clear metal complexes that contain the ligand bis-diphenyl-
phosphanylethylene sulfide {Ph2PCH2CH2}2S (PSP) have
been prepared,[16] there are, to the best of our knowledge,
no reports of coordination of PSP to transition-metal clus-
ters. We were interested in investigating the coordination
[a] Inorganic Chemistry Research Group, Chemical Physics,
Center for Chemistry and Chemical Engineering,
Lund University, Box 124, 22100 Lund, Sweden
Fax: +46-46-222-4119
E-mail: Ebbe.Nordlander@chemphys.lu.se
Homepage: http:/www.chemphys.lu.se/people/nordlander
[b] Dipartimento di Chimica, Università di Torino,
Via P. Giuria 7, 10125 Torino, Italy
[c] Department of Chemistry and Biochemistry, San Diego State
University,
5500 Campanile Drive, San Diego, CA 92182-1030, USA
[d] Department of Chemistry, University of North Texas,
1155 Union Circle, Box 305070, Denton, TX 76203, USA
[e] Dipartimento di Chimica “G. Ciamician”, Università degli
Studi di Bologna,
Via Selmi 2, 40126 Bologna, Italy
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.201201403.
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chemistry of PSP with polynuclear transition-metal com- (NCMe)] is used. Conversely, the formation of 2 cannot be
plexes; in particular, we wanted to ascertain to what extent eliminated by using an excess amount of the PSP ligand.
the thioether moiety might compete with the phosphanes The same observations have been made for the reaction be-
as a ligand to one or several transition metal(s) in a low- tween [Os3(CO)11(NCMe)] and Ph2P(CH2)5PPh2 (dppp),
oxidation state. Herein, we wish to describe the products which is isostructural to the PSP ligand.[9]
of the reaction of PSP with the mono- and bis-acetonitrile
The solution IR spectra of 1 and 2 show very similar
derivatives of [Os3(CO)12][17,18] as well as further reactions carbonyl stretching patterns, thus indicating that they pos-
of the resultant products.
sess equivalent symmetry with respect to the carbonyl li-
gands. The IR spectra also correspond well to those of
[Os3(CO)11(dppp)] and [{Os3(CO)11}2(μ-dppp)] and are
thus consistent with the PSP ligand being coordinated
through its phosphane moieties in equatorial positions in
both clusters.[5,8,20] The observation of four resonances for
Results and Discussion
Preparation of {Ph2PCH2CH2}2S (PSP)
1
the methylene protons in the H NMR spectrum of 1 (see
The original method of preparation of PSP involves
phosphination of bis(2-chloroethylene)sulfide by the di-
phenylphosphide anion.[16d] The disadvantage of this
method is the toxicity of bis(2-chloroethylene)sulfide (sulfur
mustard). We therefore developed an alternative route to
PSP that is based on the general method of anti-Markovni-
kov addition of a P–H (or an S–H or N–H) bond to a
carbon–carbon double bond, which has been used for the
preparation of a wide range of polydentate tertiary phos-
phanes as well as P,S- and P,N-type bidentate ligands.[19]
Thus, PSP was prepared by free-radical-catalysed addition
of diphenylphosphane to divinyl sulfide as shown in
Scheme 1. The conversion of divinyl sulfide to PSP was al-
most quantitative according to {1H}31P and 1H NMR spec-
troscopy of the crude product. The product was slightly
contaminated by the corresponding phosphane oxide(s),
which could be removed by chromatography, and the iso-
lated yield was only moderate (49%) owing to some decom-
position on and incomplete extraction from the column.
Attempts to prepare PSP by means of the condensation of
PPh2CH2CH2SH with PPh2CH=CH2 did not give good re-
sults.
the Exp. Sect.) is consistent with the PSP ligand being coor-
dinated in a monodentate “dangling” mode. Similarly, the
presence of only two resonances in the methylene region of
1
the H NMR spectrum of 2 indicates that the PSP ligand
is bridging two {Os3(CO)11} cluster units. Two singlets at δ
= –10.89 and –16.63 ppm are observed in the 31P{1H}
NMR spectrum of 1. The lower frequency (high-field) sing-
let is assigned to the uncoordinated phosphorus of PSP
(compared with free PSP:[16b] δ = –16.7 ppm), whereas that
at higher frequency (lower field) is attributed to the coordi-
nated phosphorus atom. This assignment has been con-
firmed by the determination of 1J and 2J 31P,187Os coupling
constants for 1 (223 and 53 Hz, respectively, at 303 K).[21]
Only one singlet at δ = –10.7 ppm is present in the
31P{1H} NMR spectrum of 2, thus indicating one single
phosphorus environment. The shift agrees with the low-
field resonance of 1, which suggests that both phosphorus
atoms are coordinated in 2. The fast-atom bombardment
(FAB) mass spectra of 1 and 2 agree with the formulations
[Os3(CO)11(PSP)] and [{Os3(CO)11}2(μ-PSP)], respectively.
The above-mentioned spectroscopic data are in complete
agreement with the expected structures for 1 and 2, which
are depicted in Figure 1.
Scheme 1. Preparation of PSP: (i) KOH, 150–200 °C; (ii) AIBN,
120 °C, 1 h.
Figure 1. Proposed structures of [Os3(CO)11(PSP)] (1) and
[{Os3(CO)11}2(μ-PSP)] (2).
Synthesis and Characterisation of [Os3(CO)11(PSP)] (1)
and [{Os3(CO)11}2(μ-PSP)] (2)
Reaction of [Os3(CO)11(NCMe)] with PSP in CH2Cl2 at
room temperature affords a mixture of two compounds,
namely, orange 1 and yellow 2. The yields of the respective
compounds are dependent on the molar ratio between the
Carbonyl Fluxionality in 1
The room-temperature (293 K) 13C NMR spectrum of 1
reactants; this suggests that the reactions of [Os3(CO)11- reveals that the carbonyl ligands are fluxional. To freeze out
(NCMe)] with PSP (to form 1) and with 1 (to form 2) are this fluxionality and determine its mechanism, a variable-
competing reactions. Thus, by using two equivalents or temperature study was carried out. The low-temperature
more of [Os3(CO)11(NCMe)], compound 2 is formed in (213 K) limiting 13C{1H} NMR spectrum of 1 shows eight
high yield although a small amount of 1 is present as a side singlets downfield of δ = 169 ppm with intensity ratios
product even when an excess amount of [Os3(CO)11- 2:2:2:1:1:1:1:1 (Figure 2) in the carbonyl region. Six carb-
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onyl resonances Ϫ two attributed to axial CO signals (rela- ment of the resonances in the low-temperature (213 K) lim-
tive intensity 2) at δ = 192.4 (2JP,CO = 8 Hz) and 184.7 ppm, iting 13C{1H} spectrum of 1 was accomplished by studying
and two equatorial CO signals (relative intensity 1) at δ = the temperature dependence of the carbonyl resonances of
176.1 and 169.5 ppm Ϫ undergo a concerted collapse 1 and by comparing the 13C{1H} NMR spectrum of 1 with
around 253 K (see Figure 2); this is consistent with a classi- the related clusters [Os3(CO)11PS][14] and [Os3(CO)11-
cal “merry-go-round” process, as outlined in Figure 3.[22,23] {P(OMe)3}].[23]
On increasing the temperature to 293 K, all the remaining
resonances broaden. The Gibbs’ free energies of activation
(ΔG϶) for the merry-go-round process(es) were calculated
to be 50.3(Ϯ1) kJmol–1 for the process that involves carb-
onyl ligands a/aЈ, f,fЈ, b and g, and 59.4(Ϯ1) kJmol–1 for
the process that involves carbonyl ligands c,cЈ, f,fЈ, d and h
(see Figure 3).
Crystal and Molecular Structure of 2
It was possible to grow crystals of 2 suitable for single-
crystal X-ray crystallography, and its crystal structure was
determined to confirm the proposed structure. The molecu-
lar structure is shown in Figure 4 and relevant bond lengths
and angles are reported in Table 1. The molecule consists
of two {Os3(CO)11} units linked by the PSP ligand. The
two triosmium triangles are oriented with their faces ap-
proximately perpendicular to each other. The phosphorus
atoms of the PSP ligand coordinate to equatorial sites of
each triosmium unit, as has been previously found in re-
lated [Os3(CO)11(PR3)] species.[8b,9,20,24,25] Bridging dimers
of similar structures to 2 have been prepared by treating
bidentate phosphanes with triosmium[9,20] and triruthen-
ium[26] clusters. Dimers that consist of two cluster units
linked by other phosphorus-based ligands have also been
prepared by treating tri- and tetraphospholanes with acti-
vated triosmium clusters.[27,28] The sulfur atom and the
methylene groups are oriented in a zigzag conformation and
the sulfur atom is not within bonding distance to any os-
mium atom. It has previously been observed that the pres-
ence of a bulky PR3 group causes a lengthening of the Os–
Figure 2. Variable-temperature 13C{1H} NMR spectra (126 MHz,
CDCl3, 213 K) of 1 showing fluxionality consistent with that de-
scribed in Scheme 2.
Figure 4. An ORTEP plot of the molecular structure of 2. Hydro-
gen atoms have been omitted for clarity. Thermal ellipsoids are at
30% probability level.
Figure 3. The fluxional CO process of 1.
Table 1. Selected bond lengths [Å] and angles [°] for 2.
For the related cluster [Os3(CO)11{P(OMe)3}], Pomeroy
and co-workers[23] were able to distinguish three distinct dy-
namic processes with significantly different activation ener-
gies. Two of these processes were of the merry-go-round
type, which operate at lower temperatures and do not in-
volve the phosphite ligand, whereas the third, a turnstile
mechanism that involves phosphite liberation, was found to
operate at significantly higher temperatures. The assign-
Os(1)–Os(2)
Os(1)–Os(3)
Os(2)–Os(3)
Os(4)–Os(5)
Os(5)–Os(6)
Os(4)–Os(6)
Os(1)–P(1)
2.888(1)
2.878(1)
2.868(1)
2.876(1)
2.888(1)
2.882(1)
2.330(2)
100.5(3)
Os(4)–P(2)
S–C(24)
S–C(25)
C(23)–C(24)
C(25)–C(26)
Os–C(ax)
Os–C(eq)
2.381(2)
1.78(1)
1.80(1)
1.53(1)
1.49(1)
1.91–1.98(1)
1.85–1.95(1)
C(24)–S–C(25)
C(26)–P(2)–Os(4) 118.9(2)
C(23)–P(1)–Os(1) 113.7(2)
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Os bonds adjacent to the phosphorus atoms[8,29] and the
two Os–Os bonds cis to the phosphorus are indeed slightly
longer than the average Os–Os distance in the parent cluster
[Os3(CO)12] [2.877(3) Å][30] but only in one triangle is the
Os–Os separation cis to the P atom the longest one [Os(1)–
Os(2) 2.888(1) Å].
As a consequence of the steric hindrance of the PSP li-
gand, a widening of the angles Os(2)–Os(1)–P(1) and
Os(6)–Os(4)–P(2) to 110.21(5) and 106.15(6)°, respectively,
is observed. In the parent carbonyl the M–M–CO angles
range from 96.1 to 99.9°.[30] The Os–P distances [Os(1)–P(1)
2.330(2) Å and Os(2)–P(2) 2.381(2) Å] fall in the range
2.28–2.40 Å, which is typical for these bonds.[29] The two
equatorial CO ligands bound to the two osmium atoms that
are coordinated by the PSP ligand show some shortening
of the Os–C distances on account of increased π backbond-
ing from the metal to the CO [Os(1)–C(3) 1.88(1) Å and
Os(4)–C(14) 1.85(1) Å].
Figure 6. An ORTEP plot of the molecular structure of 3. Hydro-
gen atoms have been omitted for clarity. Thermal ellipsoids are at
the 30% probability level.
Synthesis and Characterisation of [Os3(CO)10(μ-PSP)] (3)
Table 2. Selected bond lengths [Å] and angles [°] for 3.
Os(1)–Os(2)
Os(1)–Os(3)
Os(2)–Os(3)
Os(1)–P(1)
Os(2)–P(2)
S(1)–C(24)
S(1)–C(25)
Os(1)–C(1)
Os(1)–C(2)
C–Oeq (range)
2.9687(3)
2.8707(3)
2.8834(3)
2.343(1)
2.348(1)
1.804(6)
1.816(6)
1.936(6)
1.950(6)
1.134–1.155(7)
Os(1)–C(3)
Os(2)–C(4)
Os(2)–C(5)
Os(2)–C(6)
Os(3)–C(7)
Os(3)–C(8)
Os(3)–C(9)
Os(3)–C(10)
C–Oax (range)
1.884(6)
1.935(6)
1.967(6)
1.876(7)
1.888(7)
1.906(6)
1.951(6)
1.940(6)
1.114–1.148(7)
Cluster 3 is formed in moderate yield through treatment
of [Os3(CO)10(NCMe)2] with PSP in CHCl3 heated at re-
flux. It is also possible to form 3 by oxidative decarb-
onylation of 1 by using the oxygen-transfer reagent
Me3NO.[18] Both reactions produce several minor products,
which remain uncharacterised. Cluster 3 exhibits an νCO IR
pattern similar to that of [Os3(CO)10{μ-Ph2P(CH2)nPPh2}]
(n = 1,4).[8,20] One singlet at δ = –4.26 ppm was observed in
the 31P{1H} NMR spectrum of 3, a shift to higher fre-
quency by approximately 12 ppm relative to the free PSP
ligand. This shift difference is approximately twice as large
as that observed for 1 and 2; the additional shift might be
due to a ring contribution effect[10] as the phosphorus atom
is part of a nine-membered ring (see below). The FAB mass
spectrum of 3 is in agreement with the formulation
[Os3(CO)10(μ-PSP)] and the expected structure is depicted
in Figure 5.
Os(2)–Os(1)–P(1) 122.56(3)
Os(1)–Os(2)–P(2) 121.90(4)
C(24)–S(1)–C(25) 98.9(3)
Os(1)–P(1)–C(23) 119.6(2)
Os(2)–P(2)–C(26) 119.4(2)
The molecule conforms to an idealised C2 symmetry if
the phenyl groups attached to the phosphorus atoms are
ignored. The two phosphane moieties occupy equatorial
sites on different osmium atoms with the phosphorus atoms
cis to each other. The bridged metal–metal bond [Os(1)–
Os(2) 2.969(1) Å] is slightly longer than the two nonbridged
ones [Os(2)–Os(3) 2.883(1) Å, Os(1)–Os(3) 2.871(1) Å] as
well as the average Os–Os distance in [Os3(CO)12] (Os–Osav
2.877 Å).[30] Elongation of the bridged Os–Os bond has
also been observed in the related compounds [Os3(CO)10{μ-
Ph2P(CH2)nPPh2}] (n = 2,[31a] 4, 5[31b]), in which the diphos-
phane ligands are bridging one metal–metal bond [bridged
Os–Os bonds: 2.891(1), 2.939(1) and 2.965(2) Å for n = 2,
4 and 5, respectively]. The increase in bond length has been
ascribed to conformational requirements of the methylene
groups of the diphosphane ligand spanning the osmium–
Figure 5. Proposed structure of 3.
Crystal and Molecular Structure of 3
The crystal structure of 3 was determined to confirm its osmium bond.[8] In the molecular structure of [Os3(CO)10-
proposed structure and compare it to related [Os3(CO)10(μ- (μ-Ph2PCH2PPh2)],[31c] the diphosphane-bridged and un-
diphosphane)] clusters. The molecular structure is shown in bridged Os–Os bonds are not significantly different [Os–
Figure 6 and selected bond lengths and angles for 3 are Osbridged(av) 2.867 Å and Os–Osunbridged(av) 2.870 Å]. The
listed in Table 2. Cluster 3 consists of a triangular tri- phosphorus–osmium distances in 3 [Os(1)–P(1) 2.332(1),
osmium cluster with ten terminal carbonyl ligands and the Os(2)–P(2)2.348(1) Å]arecomparabletothosein[Os3(CO)10-
PSP ligand bridging one Os–Os edge.
{μ-Ph2P(CH2)nPPh2}] (n = 1, 2, 4, 5): Os–Pav: 2.324, 2.330,
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2.348 and 2.338 Å for n = 1, 2, 4, 5, respectively.[31] As equatorial position and the thioether moiety is in an axial
found in cluster 2, the sulfur atom is not within bonding one (isomer 4a; Figure 7), whereas in the 1,2-coordination
distance to any osmium atom.
mode, the –SCH2CH2PPh2 moiety spans a metal–metal
The two methylene groups next to each phosphorus atom bond and both the thioether and phosphane moieties are
are placed on different sides of the triosmium plane because coordinated in equatorial positions (isomer 4b; Figure 7). It
of the presence of the idealised C2 axis. The carbon–os- is not possible to make an unambiguous distinction be-
mium bonds for axial carbonyls [Os–Cav ≈ 1.95 Å] are tween these two structural isomers on the basis of the
slightly longer than the carbon–osmium distances for equa- above-mentioned spectroscopic data. Both types of isomers
torial carbonyls [Os–Cav ≈ 1.89 Å]. A further point of inter- have been detected for the related cluster [Os3(CO)10(μ-
est in the structure of 3 is the twist of the cluster ligand PPh2CH2CH2SMe)].[15a] For this cluster, it was found that
sphere; the four ligands at each metal atom maintain ap- the 1,2-isomer is the less stable (kinetically favoured) form
proximately octahedral geometry, but are twisted as a whole while the 1,1-isomer is the thermodynamically favoured
with respect to each other. This type of distortion is com- form. The 1,2-isomer is stable in the solid state and could
monly observed for derivatives of [M3(CO)12] (M = Ru, Os) be completely characterised, but it was found that it slowly
and is attributed to steric interactions between the ligands isomerises to the 1,1-isomer in solution.[15a] Comparable li-
that occur upon introduction of relatively bulky li- gand reactivity has also been observed when the symmetri-
gands[32–34] (e.g., phosphanes/phosphites).[29] Such distor- cal diphosphane ligands 4,5-bis(diphenylphosphanyl)-4-cy-
tion of the metal–carbonyl framework has also been ob- clopentene-1,3-dione (bpcd),[35] (Z)-Ph2PCH=CHPPh2,[36]
served for the related compounds [Os3(CO)10{μ-Ph2P- and
2,3-bis(diphenylphosphanyl)-N-p-tolylmaleimide
(CH2)nPPh2}] (n = 1, 2, 4, 5).[8,20,31] When toluene was used (bmi)[37] react with the activated cluster [Os3(CO)10-
as a solvent, 3 crystallised as a racemate of a conformer (MeCN)2].Eachoftheligandsreactsrapidlywith[Os3(CO)10-
with crystallographically imposed C2 symmetry (mono- (MeCN)2] to form the clusters 1,2-[Os3(CO)10(bpcd)], 1,2-
clinic, space group C2/c; see the Supporting Information).
[Os3(CO)10{(Z)-Ph2PCH=CHPPh2}] and 1,2-[Os3(CO)10-
(bmi)] as kinetic products of ligand substitution. In each of
these products the diphosphane ligand bridges one metal–
metal bond. The bridged clusters undergo isomerisation
into the chelated clusters 1,1-[Os3(CO)10(bpcd)], 1,1-
[Os3(CO)10{(Z)-Ph2PCH=CHPPh2}] and 1,1-[Os3(CO)10-
Synthesis and Characterisation of 1,1-[{Os3(CO)11}(μ-
PSP){Os3(CO)10}] (4a)
Cluster 4a is afforded in good yield when [Os3(CO)10- (bmi)]. Both phosphane-donor atoms occupy equatorial co-
(NCMe)2] is treated with 1 in CH2Cl2 at room temperature. ordination sites in each of the reported isomeric pair of
Compound 4a was also synthesised by adding a solution of clusters. On the basis of the kinetic data measured for the
Me3NO in CH2Cl2 to a solution of 2 in CH2Cl2 at room reactions, a nondissociative phosphane migration across
temperature. Multiplets in the area between δ = 2.5 and one of the Os–Os bonds has been proposed.[35–37] More re-
1
3.1 ppm in the H NMR spectrum of 4a are attributed to cently, the same type of isomerisation reaction that involves
the methylene protons of the asymmetrically bridging PSP the ligand 1,2-bis(diphenylphosphanyl)benzene has been
ligand. Two singlets at equal intensities were detected at δ studied, and a concomitant computational study on iso-
= 39.25 and –11.76 ppm in the 31P{1H} NMR spectrum of merisation reactions that involve [Os3(CO)10(P–P)] [P–P =
4a. The high-field signal is comparable to those observed diphosphane, e.g., (Z)-Ph2PCH=CHPPh2] indicate that the
for 1 and 2, which suggests that a part of the compound isomerisation occurs by means of a concerted merry-go-
consists of one triosmium triangle with an equatorially co- round process that involves one of the phosphane moieties
ordinated phosphane group. The unusual shift for the reso- and two CO groups.[38] Furthermore, similar isomerisation
nance found at δ = 39.25 ppm is similar to that of the sing- reactions have been detected for diphosphane-substituted
let observed for 1,1-[Os3(CO)10(μ-PPh2CH2CH2SMe)] at δ clusters of the general formula [H4Ru4(CO)10(P–P)] (P–P =
= 38.1 ppm[15a] (see below) and indicates that there might diphosphane).[39]
be a ring-contribution effect[10] to the shift of the second
phosphorus atom. This is consistent with the hypothesis
that 4a consists of two cluster units bridged by a PSP ligand
with one phosphane group coordinating to one trinuclear
unit and the thioether and second phosphane moieties co-
ordinating to the second osmium triangle. The FAB mass
spectrum of 4a is consistent with the formulation [Os6(CO)21-
(PSP)].
Two likely isomers exist for [{Os3(CO)11}(μ-
PSP){Os3(CO)10}] (4a and 4b), and these structures differ
in the coordination mode of the –SCH2CH2PPh2 part of
the PSP ligand to the {Os3(CO)10} unit of the product. In
the 1,1-coordination mode, the –SCH2CH2PPh2 moiety
(PSP)]: (A) [{Os3(CO)11}{μ-(1,1)-PSP}{Os3(CO)10}] (4a) and (B)
chelates one metal atom so that the phosphane is in an [{Os3(CO)11}{μ-(1,2)-PSP}{Os3(CO)10}] (4b).
Figure 7. Proposed structures for the two isomers of [Os6(CO)21-
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Considering the known isomerisation reactions men- spectrum of 1,1-[{Os3(CO)11}(μ-PSP){Os3(13CO)10}] (Fig-
tioned above, it was thought that both isomeric forms of ure 9) shows five resonances; one high-frequency (low-field)
[{Os3(CO)11}(μ-PSP){Os3(CO)10}] might exist and that 4a doublet and four triplets (due to 2JC,C couplings) downfield
might be the (thermodynamically favoured) 1,1-isomer (see of δ = 185 ppm, with intensity ratios 1:1:1:1:1 at 185.7
Figure 7). To estimate the energy difference between the two (2JC,C = 36 Hz), 187.4 (2JC,C = 32 Hz), 187.9 (2JC,C
=
isomers, DFT calculations were performed. The geometry- 36 Hz), 190.2 (2JC,C = 32 Hz) and 190.7 ppm (2JC,P = 6 Hz)
optimised structures for 4a and 4b are shown in Figure 8. assigned to axial carbonyls and five resonances upfield of δ
The calculated free-energy difference between 4a and 4b is = 185 ppm, with intensity ratios 1:1:1:1:1 at δ = 181.1,
small (1.7 kcalmol–1) and favours the 1,1-isomer. The com- 178.3, 176.7, 174.2 and 172.9 ppm. The lack of a large 2JC,C
puted Keq value at room temperature for the 4a/4b equilib- coupling for the latter resonance indicates that the ligand
rium is 17.7–1, which is in excellent agreement with the ob- sulfur (rather than a carbonyl ligand) is axially coordinated
servation of only cluster 4a in the NMR spectra of ther- in the {Os3(CO)10} unit of 4a. The overall pattern of the
mally equilibrated samples that contain cluster 4. The en- 13C NMR spectrum of [{Os3(CO)11}(μ-PSP){Os3(13CO)10}]
ergy difference computed (under identical conditions) for resembles
that
of
1,1-[Os3(CO)10(PS)]
(PS
=
the isomers of [Os3(CO)10(μ-PPh2CH2CH2SMe)] parallels Ph2PCH2CH2SMe; see above).[15a] The only difference is
that found in 4a and 4b; here the 1,1-isomer lies the appearance of the doublet at δ = 190.7 ppm for
2.3 kcalmol–1 lower in energy than the 1,2-isomer.[15c] The [{Os3(CO)11}(μ-PSP){Os3(13CO)10}] (versus 189.7 ppm for
decreased exothermicity in the 4a/4b isomers relative to the 1,1-[Os3(CO)10(PS)]) that is assigned to the carbonyl trans
isomeric [Os3(CO)10(μ-PPh2CH2CH2SMe)] clusters poss- to the sulfur; this doublet is the lowest-field resonance in
ibly reflects the steric strain associated with the introduc- [{Os3(CO)11}(μ-PSP){Os3(13CO)10}] but the second-lowest-
tion of an extra Os3(CO)11 moiety into the former pair of field resonance detected in the spectrum of 1,1-[Os3(CO)10-
cluster isomers.
(PS)]. In both spectra, ten unique resonances could be ob-
served as expected for an unsymmetrical P,S-coordinated
cluster with the sulfur in an apical position.
Figure 8. B3LYP-optimised structures for clusters 4a (left) and 4b
(right).
Variable-Temperature NMR Spectroscopic Studies of
Selectively 13CO-Labeled Versions of 4a
Figure 9. The (partial) 13C{1H} NMR spectrum (152.4 MHz,
CD2Cl2) of 1,1-[{Os3(CO)11}(μ-PSP){Os3(13CO)10}] (4a) recorded
at 213 K; only resonances from the axial carbonyl ligands are
shown.
To gain a deeper understanding of the dynamic processes
and coordination mode(s) of the PSP ligand in 4a, a vari-
able-temperature 13C{1H} NMR spectroscopic study was
In the low-temperature limiting spectrum of the corre-
undertaken. Because of the large number of possible CO- spondingly
labelled
1,1-[{Os3(13CO)11}(μ-PSP){Os3-
ligand environments (up to 21), the {Os3(CO)10} and (CO)10}] cluster (Figure 10), eleven resonances at δ = 192.4
{Os3(CO)11} cluster subunits of 4a were selectively enriched (a/aЈ), 191.8 (a/aЈ), 184.5 (f/fЈ), 184.2 (f/fЈ), 183.0 (c/cЈ),
by
preparing
the
compounds
[{Os3(13CO)11}(μ- 182.8 (c/cЈ), 176.0 (b), 175.6 (h), 171.6 (d), 171.3 (e) and
PSP){Os3(CO)10}] and [{Os3(CO)11}(μ-PSP){Os3(13CO)10}] 169.2 ppm (g) were observed (the bold lettering in parenthe-
according to the methods employed for the synthesis of 1 ses corresponds to the assignment in Figure 3). The reso-
and 4a (see the Exp. Sect.), thus facilitating identification nances at δ = 192.4, 191.8, 184.5, 184.2, 183.0 and
of the resonances due to these subunits and selective obser- 182.8 ppm are assigned as the axial carbonyls but occur as
vation of the fluxional processes at each subunit. The for- pairs. The reason for the presence of multiple resonances is
mer compound was made by treating [Os3(13CO)11(NCMe)] most likely that diastereomeric forms of the complex are
with PSP. The enriched version of 1 was isolated from the formed. As mentioned above, the {Os3(CO)10[1,1-PS(P)]}
product and treated further with [Os3(CO)10(NCMe)2]. The subunit is a chiral entity in itself; when it is combined with
latter compound was obtained from the reaction of 1 with the chirality at the coordinated sulfur atom, diastereomers
[Os3(13CO)10(NCMe)2]. The low-temperature 13C NMR (two sets of enantiomeric pairs) are formed. The five reso-
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nances upfield of δ = 180 ppm [176.0 (b), 175.6 (h), 171.6 Characterisation of the Metastable Cluster 1,2-[{Os3-
(d), 171.3 (e) and 169.2 ppm (g)] are ascribed to five equato- (CO)11}(μ-PSP){Os3(CO)10}] (4b)
rial carbonyls.
In an effort to detect a possible (metastable) 1,2-isomer,
the reaction between [Os3(CO)10(NCMe)2] and [Os3(CO)11-
(PSP)] was carried out in an NMR tube and monitored by
31P{1H} NMR spectroscopy. Immediately upon mixing of
the reactants, two singlets of equal intensity were observed
at δ = –11.76 and 0.5 ppm. Over a period of 24 h, the singlet
at 0.5 ppm gradually decreased in intensity with a concomi-
tant increase in the intensity of a new singlet at δ =
39.3 ppm. The sum of the intensities of the singlets at δ =
0.5 and 39.3 ppm remained constant during the reaction,
thus indicating a direct (and quantitative) interconversion/
isomerisation. The final 31P{1H} NMR spectrum is iden-
tical to that of 4a and the initial spectrum observed upon
mixing of the reactants is very similar to that of the meta-
stable cluster 1,2-[Os3(CO)10(μ-PPh2CH2CH2SMe)] (which
exhibits a singlet at δ = –0.6 ppm), thereby suggesting that
this spectrum might be attributed to the kinetically fav-
oured isomer 4b. It is understandable that the formation of
4b is kinetically favoured; presumably, an intermediate in
the reaction of [Os3(CO)11(PSP)] with [Os3(CO)10(NCMe)2]
is the cluster [{Os3(CO)11}(μ-PSP){Os3(CO)10(NCMe)}] in
which the free phosphane moiety of the PSP ligand in
[Os3(CO)11(PSP)] (1) has replaced one of the two acetoni-
trile ligands of [Os3(CO)10(NCMe)2]. As the PSP ligand and
the remaining acetonitrile ligand are expected to be coordi-
nated to adjacent atoms, replacement of the second acetoni-
trile ligand by the thioether moiety leads to the initial for-
Figure 10. Variable-temperature (VT) 13C{1H} NMR spectra of
1,1-[{Os3(13CO)11}(μ-PSP){Os3(CO)10}] (4a) (151 MHz, CD2Cl2)
in the carbonyl region. The fluxional process is identical to that
in 1 (see Figures 2 and 3). However, because the P,S-coordinated
{Os3(CO)10} subunit is asymmetric, there are 11 independent sig-
nals. There is also a minor isomer (marked with *), which is proba-
bly due to a different (minor) diastereomer (see text).
mation of 4b (Scheme 2).
On increasing the temperature to 273 K, the resonances
at δ = 183.0 ppm broaden and merge, probably because the
{Os3(CO)10} subunit, which is asymmetric (as a conse-
quence of the phosphorus and sulfur coordination), is mov-
ing sufficiently fast to average the signals on the NMR spec-
troscopic timescale. The fluxional process detected for the
{Os3(CO)11} subunit is identical to that in 1 (see Figures 2
and 3) despite the steric bulk of the second cluster unit in
close vicinity of the {Os3(CO)11} subunit. The calculated
free energy of activation (ΔG϶) is (49.0Ϯ1) kJmol–1 for the
Scheme 2. The reaction of 1 with [Os3(CO)10(NCMe)2] yields 4b by
stepwise substitution of the acetonitrile ligands.
The dynamic processes and coordination mode(s) of the
merry-go-round process that involves carbonyl ligands a/aЈ, PSP ligand in 4b were investigated by variable-temperature
f,fЈ, b and g, and (59.6Ϯ1) kJmol–1 for the process that (VT) 13C NMR spectroscopy (Figure 11). The 13C NMR
involves carbonyls c, cЈ, f, fЈ, d and h. We were unable to spectrum in the CO region of the selectively 13CO-enriched
observe any intermolecular migration of 13CO between the compound 1,2-[{Os3(CO)11}(μ-PSP){Os3(13CO)10}] shows
{Os3(CO)11} and the {Os3(CO)10} subunits in any of the four singlets downfield of δ = 185 ppm, with intensity ratios
enriched samples of 4a. The above-mentioned NMR spec- 1:1:2:2 at δ = 197.4, 195.3, 194.7 and 185.2 ppm. These sig-
tra are consistent with the calculated structure for the most nals have similar chemical shifts as the resonances assigned
stable form of [{Os3(CO)11}(μ-PSP){Os3(CO)10}] [i.e., in to the axial carbonyls in the cluster 1,2-[Os3(CO)10(μ-
which one phosphane moiety and the thioether coordinate PPh2CH2CH2SMe)] (196.3, 194.5, 193.5, 193.2 and
in equatorial and axial coordination positions, respectively, 184.0 ppm).[15a] One difference is that the resonance(s) as-
so that the ligand chelates one osmium atom of the signed to the axial carbonyls coordinated to the same metal
Os3(CO)10 fragment (see Figures 7 and 8)].
as the phosphane group are not resolved in 4b, whereas they
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are separated by approximately 0.3 ppm in the spectrum of (μ-PSP){Os3(13CO)10}]
(4b)
and
1,2-[Os3(CO)10(μ-
1,2-[Os3(CO)10(μ-PPh2CH2CH2SMe)]. Despite several PPh2CH2CH2SMe)][15a] are sufficient to conclude that these
attempts to generate a clean sample of 1,2-[{Os3(CO)11}(μ- cluster units are isostructural. Thus, eight resonances were
PSP){Os3(13CO)10}], additional 13CO signals due to resid- assigned to the {Os3(CO)10} subunit (Figure 12): the four
ual starting materials were identified (Figure 12), namely, resonances in 1:1:2:2 relative intensities at δ = 197.2, 195.2,
[Os3(13CO)11(MeCN)], [Os3(13CO)10(MeCN)2] and 1 (see 194.4 and 185.1 ppm represent the axial carbonyl ligands
Figure 2).
and the four resonances with intensity ratios 1:1:1:1 at δ =
180.0, 178.7, 173.6, and 173.4 ppm represent the equatorial
carbonyls. Taken together, the similarities of the IR, 1H,
31P{1H} and 13CO{1H} data to those previously obtained
for 1,2-[Os3(CO)10(μ-PPh2CH2CH2SMe)] are sufficient to
characterise 4b as having both phosphorus atoms coordi-
nated to the respective metal clusters in equatorial sites, and
the 13C{1H} NMR spectroscopic study confirms the equa-
torial coordination of the sulfur site (see Scheme 3). The
structure of cluster 4b was indirectly confirmed by the fact
that 4a could be obtained in apparent quantitative yield by
rearrangement of 4b in CH2Cl2 over 1–2 days at room tem-
perature.
Two plausible mechanisms exist by which cluster 4b
might isomerise to the more stable isomer 4a. In the first
mechanism, the bound thioether moiety dissociates, a carb-
onyl ligand migrates to the osmium atom from which the
thioether has dissociated and the thioether coordinates at
the new vacant coordination site located at the phosphane-
substituted osmium centre. In the second mechanism, there
is a nondissociative migration of the thioether moiety from
its initial locus to the adjacent osmium atom to which the
phosphane is coordinated. Coupled with the thioether mi-
gration is the subsequent (or concomitant) carbonyl mi-
gration (Scheme S1 in the Supporting Information). In the
case of the isomerisation of 1,2-[Os3(CO)10(μ-
PPh2CH2CH2SMe)]
to
1,1-[Os3(CO)10(μ-PPh2CH2-
CH2SMe)],[15a] we have found that ΔS϶ is negative, and this
allows us to rule out the former process and strongly sup-
ports a nondissociative reaction. DFT calculations on the
dissociation of the thioether moiety from 1,2-[Os3(CO)10(μ-
Ph2PCH2CH2SMe)] to furnish the coordinatively unsatu-
rated cluster [Os3(CO)10(κP-Ph2PCH2CH2SMe)] show that
the latter species lies 4.5 kcalmol–1 higher in enthalpy than
the rate-limiting step in the nondissociative manifold.[15c]
The isomerisation of 4b to 4a is likely to proceed by a paral-
lel process.
Figure 11. Variable-temperature (VT) 13C{1H} NMR spectra of
(metastable) 1,2-[{Os3(CO)11}(μ-PSP){Os3(CO)10}] (4b) in the
carbonyl region (125.7 MHz, CDCl3).
In terms of the nondissociative process, we have shown
that isomerisation reactions similar to that discussed above
occur in [Os3(CO)10(P–P)] (P–P = diphosphane) clus-
ters[35–38] A computational study[38] shows that the favoured
mechanism for isomerisation is a merry-go-round mecha-
nism in the equatorial plane of the triangular cluster. An
alternative mechanism that was explored but found to be
energetically unfavourable involves three consecutive con-
rotatory permutations of one phosphane moiety and CO
groups across an Os–Os vector. The first in-plane migration
results in the migration of a phosphane from an equatorial
position into an axial position. The isomerisation to the
Figure 12. Expansion of the 213 K 13C{1H} spectrum of 4b show-
ing the assignment of the carbonyl resonances. Resonances due to
[Os3(CO)11(NCMe)] and 1 are marked with Δ and O, respectively.
The quality and complexity of the VT 13C NMR spectra thermodynamically more stable chelated isomer (Peq, Peq)
of (selectively enriched) 4b precluded a full assignment but is then completed through sequential in-plane migration se-
the similarities in the overall patterns of 1,2-[{Os3(CO)11}- quences about the same Os–Os vector, with one of the mi-
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grations involving a μ2-phosphane moiety. There is a dis- prepared and structurally characterised five new clusters;
tinct energetic penalty experienced when the phosphane mi- in three of these (clusters 1–3), the PSP ligand coordinates
grates from its preferred equatorial disposition to an axial through its phosphane moieties only. Spectroscopic data
orientation, thus making this particular manifold noncom- indicate coordination of the sulfur and the two phosphorus
petitive relative to the single-step merry-go-round isomeri- atoms of PSP in 4a. The selectively enriched samples of 4a,
sation process in [Os3(CO)10(P–P)]. DFT calculations on 1,1-[{Os3(13CO)11}(μ-PSP){Os3(CO)10}] and 1,1-[{Os3-
the dynamical behaviour in our earlier system [Os3(CO)10- (CO)11}(μ-PSP){Os3(13CO)10}], were successfully used to
(MeSCH2CH2PPh2)] reveal a migratory preference for thio- determine the coordination modes of the donor atoms of
ether over phosphane migration in the conrotatory in-plane PSP in the cluster. In the {Os3(CO)10} unit of compound
exchange sequences about the Os–Os vector.[15c] In fact, the 4a, the sulfur is coordinated in an axial position to the same
presence of a single thioether moiety in [Os3(CO)10- metal atom to which a phosphorus atom is equatorially co-
(MeSCH2CH2PPh2)] facilitates consecutive in-plane mi- ordinated. The {Os3(CO)11} unit of 4a has a phosphane
grations of the thioether and CO groups such that the group coordinated in an equatorial position. Computa-
merry-go-round process becomes unfavourable. The dy- tional modelling indicates that the observed coordination
namics for the isomerisation of the thiophosphane moiety mode of the PSP ligand is that of lowest energy for the
in [Os3(CO)10(MeSCH2CH2PPh2)] has been successfully general cluster [{Os3(CO)11}(μ-PSP){Os3(CO)10}]. The
modelled, and Scheme 3 shows the energetically preferred presence of 11 unique resonances that occur as pairs in 1,1-
route for the bridge-to-chelate isomerisation of the thio- [{Os3(13CO)11}(μ-PSP){Os3(CO)10}] indicates the presence
phosphane ligand in [Os3(CO)10(S–P)]. The migratory pro- of diastereomers.
cess by which 4b transforms to 4a is likely to follow the
same route exhibited by [Os3(CO)10(MeSCH2CH2PPh2)].
The unstable cluster 4b could be identified in situ when
preparing 4a. The sulfur and a phosphorus coordinate to
different osmium atoms of the {Os3(CO)10} unit in equato-
rial positions, whereas the remaining phosphane group in
the PSP ligand is equatorially coordinated to the {Os3-
(CO)11} unit. As in the case of 4a, the unstable cluster 4b
could also be studied by the correspondingly enriched ver-
sions 1,2-[{Os3(13CO)11}(μ-PSP){Os3(CO)10}] and 1,2-
[{Os3(CO)11}(μ-PSP){Os3(13CO)10}]. Cluster 4b slowly con-
verts to 4a. This type of isomerisation is one of relatively
few examples of nondestructive rearrangement of tri-
osmium clusters with phosphane or thioether ligands in the
coordination sphere. Both the cluster framework and the
coordinated ligand(s) remain intact throughout the iso-
merisation process.
Experimental Section
General: All reactions were carried out under an atmosphere of dry
nitrogen using standard Schlenk and vacuum-line techniques. The
solvents were distilled from appropriate drying agents prior to use.
Infrared spectra were recorded as solutions in 0.5 mm NaCl cells
with Nicolet 20SXC and Avatar 360 FTIR spectrometers using car-
bon dioxide as calibrant. Fast-atom bombardment (FAB) mass
spectra were obtained with a JEOL SX-102 spectrometer using 3-
nitrobenzyl alcohol as matrix and CsI as calibrant. Proton and 31
P
Scheme 3. Nondissociative mechanism for thioether migration in
[Os3(CO)10(S–P)] clusters; 1,2-Peq,Seq corresponds to 4b, 1,1-Peq,Sax
corresponds to 4a.
NMR spectra were recorded with Varian Unity 300 MHz, Bruker
DRX500 500 MHz and Bruker DRX600 600 MHz spectrometers.
Routine separations of products were performed by thin-layer
chromatography using commercially prepared glass plates, pre-
coated with 0.25 mm Merck Silica gel 60. Column chromatography
was carried out using silica gel (Merck Silica gel 60, 0.040–
0.063 mm, 230–400 mesh, ASTM) columns, initially packed in
CH2Cl2. The starting materials, [Os3(CO)11(NCMe)] and [Os3-
(CO)10(NCMe)2], were synthesised according to literature meth-
ods.[18]
Conclusion
We have found that the mixed-donor ligand PSP, which
contains two phosphane and one thioether moieties, readily
coordinates to trinuclear osmium compounds. To the best
of our knowledge, coordination of the thioether moiety of
PSP to a metal has not been observed without prior coordi-
nation of the phosphane groups. This is also the case when
Preparation of Divinyl Sulfide: Divinyl sulfide was prepared accord-
ing to a published method.[40] In a typical reaction, potassium hy-
droxide (20 g, 0.36 mol) and bis(2-hydroxyethyl)sulfide (20 mL,
PSP is coordinated to trinuclear osmium clusters. We have 0.134 mol) were mixed in a distillation apparatus. The mixture was
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carefully heated under a nitrogen stream until the reaction started
Synthesis of [Os3(CO)10(μ-PSP)] (3)
(ca. 150–200 °C). When the temperature exceeded approximately
150 °C, water and product were formed and distilled. The water
was separated from the product in an extraction flask. The product
was then distilled at 760 Torr and the fraction collected at 92–93 °C
was collected. The product was stored over molecular sieves (12 Å)
in a freezer. 1H NMR (CDCl3, 300 MHz, 298 K): δ = 5.31 (d, 3JH,H
Method I: [Os3(CO)10(NCMe)2] (93 mg, 0.150 mmol) and PSP
(93 mg, 0.100 mmol) were dissolved in CHCl3 (30 mL). The solu-
tion was heated at reflux for 3 h. The solvent was removed under
reduced pressure at 40 °C and the crude product was separated by
thin-layer chromatography using a 3:2 hexane/CH2Cl2 mixture as
eluent. Three bands were isolated; in order of decreasing Rf:
[Os3(CO)10(μ-PSP)] (3), red, 21 mg (0.016 mmol) followed by two,
as yet, uncharacterised, yellow fractions.
3
= 9 Hz, 2 H trans to S), 5.32 (d, JH,H = 17 Hz, 2 H cis to S), 6.41
3
3
(dd, JH,H_cis = 9 Hz; JH,H_trans = 17 Hz, 2 H, SCH) ppm.
Preparation of PSP: The reagents divinyl sulfide (909 mg,
10.5 mmol), diphenylphosphane (3.92 g, 21.1 mmol) and azobis-
(isobutyronitrile) (AIBN, 0.1 g, 0.169 mmol) were heated in a
Schlenk tube at approximately 120 °C under a nitrogen flow for 1 h
and then dried under reduced pressure for 1 h at 120 °C. The prod-
uct was filtered through a silica column using dichloromethane as
eluent. Separation by TLC, using a CHCl3/hexane mixture (1:4
v/v) as eluent, yielded one fraction. The last part of the eluate was
slightly contaminated and was therefore discarded. The residual
oil obtained after removal of solvent under reduced pressure was
triturated with hexane until a white crystalline solid was formed.
Method II: Me3NO (2.95 mg, 0.039 mmol) was dissolved in CH2Cl2
(20 mL). This solution was transferred dropwise over 20 min to a
stirred solution of [Os3(CO)11(η1-PSP)] (50 mg, 0.037 mmol) in
CH2Cl2. The solution was stirred at room temperature for 20 h.
The solvent was removed under reduced pressure and the crude
product was separated by thin-layer chromatography using a 3:2
hexane/CH2Cl2 mixture as eluent. Four bands were recovered, in
order of decreasing Rf: [Os3(CO)10(μ-PSP)] (3), red, 7 mg
(0.0053 mmol) followed by three, as yet unidentified, yellow frac-
tions. For 3: IR [ν(CO); in hexane]: ν = 2085 (m–s), 2020 (m), 2011
˜
(s), 2002 (vs), 1976 (vw), 1957 (w) cm–1. 1H NMR (CDCl3): δ =
3.0 (m, 2 H), 2.2 (m, 2 H) 7.0–7.8 (m, 20 H) ppm. 31P{1H} NMR
(H3PO4: δ = 0 ppm, downfield positive): δ = –4.3 (s, 2 P) ppm.
1
Yield: 2.35 g (49%), m.p. 58–60 °C. H NMR (CDCl3, 300 MHz):
δ = 2.27 (m, 4 H, CH2S), 2.58 (m, 4 H, PCH2), 7.3–7.5 (m, 20 H)
ppm. 31P{1H} NMR (H3PO4: δ = 0 ppm, downfield positive): δ =
–16.0 (s, 2 P) ppm. 13C{1H} NMR (CDCl3, 150.9 MHz): δ = 27.98
Synthesis of 1,1-[{Os3(CO)11}(μ-PSP){Os3(CO)10}] (4a)
2
1
(d, JC,P = 21.3 Hz, 2 C, CH2S), 28.31 (d, JC,P = 14.89 Hz, 2 C,
Method I: [Os3(CO)11(PSP)] (30 mg, 0.022 mmol) was dissolved in
CH2Cl2 (5 mL), which was added dropwise over a period of 10 min
to a stirred solution of [Os3(CO)10(NCMe)2] (42 mg, 0.044 mmol)
in CH2Cl2 (15 mL). The solution was stirred at room temperature
for 2 h. The solvent was then removed under reduced pressure at
40 °C. The crude product was separated by TLC eluent (hexane/
CH2Cl2, 3:2 v/v) to yield orange [Os6(CO)21(PSP)] (4a) 50%.
3
PCH2), 128.38 (d, JC,P = 6.64 Hz, 8 C, meta-C, Ph), 128.62 (s, 4
C, para-C, Ph), 132.62 (d, 2JC,P = 18.6 Hz, 8 C, ortho-C, Ph), 137.66
1
(d, JC,P = 13.1 Hz, 4 C, ipso-C, Ph) ppm.
Synthesis of [Os3(CO)11(PSP)] (1): In a typical reaction, [Os3-
(CO)11(NCMe)] (100 mg, 0.109 mmol) was dissolved in dichloro-
methane (10 mL). This solution was added dropwise over a period
of 20 min to a stirred solution of PSP (100 mg, 0.218 mmol) in
CH2Cl2 (20 mL). The solution was stirred at room temperature un-
til no νCO resonances due to the starting material could be detected
(1.5 h). The solvent was removed under vacuum and the crude
product was separated by thin-layer chromatography using a 1:1
hexane/CH2Cl2 mixture as eluent. Three bands were recovered, in
order of decreasing Rf: [{Os3(CO)11}2(μ-PSP)] (2), yellow, 30 mg
(0.013 mmol); [Os3(CO)11(PSP)] (1), yellow, 58 mg (0.043 mmol)
followed by 5 mg of one, as yet, uncharacterised, yellow fraction.
Method II: Me3NO (1.31 mg, 0.0174 mmol) was dissolved in a 1:1
CH2Cl2/MeCN solution (2.5 mL). This solution was added drop-
wise over a period of 20 min to a solution of [{Os3(CO)11}2(μ-PSP)]
(38 mg, 0.0171 mmol). The mixture was stirred overnight and the
solvent was removed under reduced pressure at 40 °C. Separation
by TLC, eluent hexane/CH2Cl2 (3:2 v/v), yielded orange [Os6-
(CO) (PSP)] in 30% yield. For 4a: IR [ν(CO); in hexane]: ν = 2109
˜
21
(m), 2088 (m), 2071 (w), 2057 (s), 2039 (s), 2021 (vs), 2013 (ms),
1
1993 (s), 1982 (m) cm–1. H NMR (CDCl3): δ = 2.9 (m, 2 H), 2.8
IR (νCO; hexane): ν = 2108 (m), 2056 (s), 2034 (w), 2019 (vs), 2002
˜
(m, 2 H), 2.6 (m, 2 H), 2.4 (m, 2 H), 1.8 (m) ppm. 31P{1H} NMR
(vw), 1991 (mw), 1980 [mw(b)] cm–1. 1H NMR (in CDCl3): δ = 2.9
(m, 2 H), 2.5 (m, 2 H), 2.3 (m, 2 H), 2.1 (m, 2 H), 7.3–7.5 (m, 20
H) ppm. 31P{1H} NMR (H3PO4: δ = 0 ppm, downfield positive):
δ = –10.9 (s, 1 P), –16.6 (s, 1 P) ppm. 13C{1H} NMR (126 MHz,
(H3PO4: δ = 0 ppm): δ = 39.3 (s, 1 P), –11.8 (s, 1 P) ppm. 13C{1H}
NMR (CD2Cl2, 125.8 MHz, 213 K) of 1,1-[{Os3(13CO)10}(μ-
2
PSP){Os3(CO)11}]: δ = 190.7 (d, JC,P = 6 Hz, 1 C), 190.2 (2JC,C
=
2
2
2
32 Hz, 1 C), 187.9 (t, JC,C = 36 Hz, 1 C), 187.4 (t, JC,C = 32 Hz,
CDCl3, 213 K): δ = 192.4 (d, JP,C = 8.0 Hz, 1 C), 184.7 (s, 1 C),
2
1 C), 185.7 (t, JC,C = 36 Hz, 1 C), 181.1 (s, 1 C), 178.3 (s, 1 C),
183.3 (s, 1 C), 176.1 (s, 1 C), 175.9 (s, 1 C), 172.1 (s, 1 C), 171.8 (s,
1 C), 169.5 (s, 1 C) ppm. Calcd. for 1: C 35.0, H 2.10, P 4.60, S
2.40, N 0; found C 34.95, H 2.15, P 4.45, S 2.30, N Ͻ0.2,
176.7 (s, 1 C), 174.2 (s, 1 C), 172.9 (s, 1 C) ppm. 13C{1H} NMR
(CDCl3,
150.8 MHz,
213 K)
of
1,1-[{Os3(CO)10}(μ-
PSP){Os3(13CO)11}]: δ = 192.4 (s, 1 C), 191.8 (s, 1 C), 184.5(s, 1
C), 184.2 (s, 1 C), 183.0 (s, 1 C), 182.8 (s, 1 C), 176.0 (s, 1 C), 175.6
(s, 1 C), 171.6 (s, 1 C), 171.3 (s, 1 C) 169.2 (s, 1 C) ppm.
Synthesis of [{Os3(CO)11}2(μ-PSP)] (2): In a typical reaction,
[Os3(CO)11(NCMe)] (208 mg, 0.226 mmol) and PSP (52 mg,
0.113 mmol) were dissolved in CH2Cl2 (30 mL) and stirred at room
temperature until no νC–O resonances due to the starting material
could be detected (2 h). The solvent was then removed under vac-
uum at 40 °C. The crude product was separated by TLC using a
hexane/CH2Cl2 mixture (1:1 v/v) as eluent and yielded two bands;
in order of decreasing Rf: [{Os3(CO)11}2(μ-PSP)], yellow, 150 mg
Synthesis of 1,2-[{Os3(CO)11}(μ-PSP){Os3(CO)10}] (4b): The com-
pound 1,2-[{Os3(CO)11}(μ-PSP){Os3(CO)10}] was identified as an
intermediate in the preparation of 4a. An amount of [Os3-
(CO)11(PSP)] (30 mg, 0.022 mmol) was dissolved in CH2Cl2 (5 mL),
which was added dropwise over a period of 10 min to a stirred
(0.067 mmol); [Os3(CO)11(PSP)], orange 5 mg (0.0037 mmol). IR solution of [Os3(CO)10(NCMe)2] (42 mg, 0.044 mmol) in CH2Cl2
[ν(CO); in hexane]: ν = 2107 (m), 2054 (s), 2033 (w), 2020 (vs),
(15 mL). The solution was stirred at room temperature for 15 min.
˜
1
2002 (vw), 1990 [mw (b)], 1977 [w (b)] cm–1. H NMR (CDCl3): δ The solvent was then removed under reduced pressure to yield
= 2.8 (m, 2 H), 2.3 (m, 2 H), 7.2–7.5 (m, 20 H) ppm. 31P{1H} orange 1,2-[Os6(CO)21(PSP)] (50%). 31P{1H} NMR (CDCl3,
NMR (H3PO4: δ = 0 ppm, downfield positive): δ = –10.7 (s, 2 P)
ppm.
303 K): δ = –11.76 (s, 1 P), 0.5 (s, 1 P) ppm. 13C{1H} NMR
(CDCl3, 213 K) of 1,2-{Os3(CO)11}(μ-PSP){Os3(13CO)10}: δ =
Eur. J. Inorg. Chem. 2013, 2447–2459
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197.2 (s, 1 C), 195.2 (s, 1 C), 194.4 (s, 2 C), 185.1 (s, 2 C), 180.0 (s, 1.39 Å, angle C–C–C: 120°). The phenyl and methylene hydrogen
1 C), 178.7 (s, 1 C), 173.6 (s, 1 C), 173.4 (s, 1 C), 174.0 (s, 1 C),
172.1 (s, 1 C) ppm.
atoms were added in calculated positions (dC–H = 0.96 Å). The final
refinement on F2 proceeded by full-matrix least-squares calcula-
tions (SHELXL 97)[47] using anisotropic thermal parameters for all
the non-hydrogen atoms. The phenyl and methylene hydrogen
atoms were assigned an isotropic thermal parameter 1.2 times Ueq
of the carbon atoms to which they were attached.
Computational Methodology: The DFT calculations reported here
were performed with the Gaussian 09 package of programs.[41] The
calculations were carried out with the B3LYP functional, which
utilizes the Becke three-parameter exchange functional (B3)[42]
combined with the correlation functional of Lee, Yang and Parr
(LYP).[43] The osmium atoms were described by Stuttgart–Dresden
effective core potentials (ecp) and the SDD basis set, whereas the
6-31G(dЈ) basis set, as implemented in the Gaussian 09 program
package, was employed for the remaining atoms. The geometry-
optimized structures reported here represent minima based on zero
imaginary frequencies (positive eigenvalues), as established by fre-
quency calculations using the analytical Hessian. The geometry-
optimised structures have been drawn with the JIMP2 molecular
visualisation and manipulation program.[44]
X-ray Data Collection and Structure Determination of 3: The X-ray
intensity data for 3 were measured with a Bruker AXS SMART
2000 diffractometer, equipped with a CCD detector, using Mo-Kα
radiation (λ = 0.71073 Å) at room temperature. Cell dimensions
and the orientation matrix were initially determined from least-
squares refinement on reflections measured in three sets of 20 expo-
sures collected in three different ω regions and eventually refined
against 5905 reflections. A full sphere of reciprocal space was
scanned by 0.3° ω steps. Intensity decay was monitored by recol-
lecting the initial 50 frames at the end of the data collection and
analysing the duplicate reflections. The collected frames were pro-
cessed for integration by using the SAINT program and an empiri-
cal absorption correction was applied using SADABS[48] on the
basis of the Laue symmetry of the reciprocal space. The structure
was solved by direct methods (SIR 97)[49] and subsequent Fourier
syntheses and refined by full-matrix least-squares on F2
(SHELXTL)[50] using anisotropic thermal parameters for all non-
hydrogen atoms. The phenyl and methylene hydrogen atoms were
added in calculated positions (dC–H = 0.96 Å) and assigned an iso-
tropic thermal parameter 1.5 and 1.2 times Ueq of the carbon atoms
to which they were attached. Crystal data and other experimental
details for 2 and 3 are reported in Table 3.
Crystallography: Yellow crystals of 2 were grown by slow evapora-
tion from a dichloromethane/n-hexane solution at 4 °C. Cluster 3
was crystallised as bright orange plates from a dichloromethane
solution at –10 °C. Crystal data and experimental details of the
data collections and structure refinements for 2 and 3 are summa-
rised in Table 3.
X-ray Data Collection and Structure Determination of 2: The dif-
fraction experiments were carried out at room temperature with a
fully automated Enraf–Nonius CAD-4 diffractometer using graph-
ite-monochromated Mo-Kα radiation. The unit-cell parameters
were determined by a least-squares fitting procedure using 25 re-
flections. Data were corrected for Lorentz and polarisation effects.
A decay (32%) and an empirical absorption correction using the
azimuthal scan method were applied.[45] The positions of the metal
atoms were found by direct methods using the SHELXS 97 pro-
gram.[46] Least-squares refinements and Fourier-difference synthe-
ses revealed all the remaining non-hydrogen atoms and the presence
of some peaks attributable to a highly disordered CH2Cl2 molecule.
The phenyl rings were treated like ideal hexagons (length C–C:
CCDC-821723 (for 2) and -821724 (for 3) contain the supplemen-
tary crystallographic data for this paper. These data can be ob-
tained free of charge from The Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif.
Supporting Information (see footnote on the first page of this arti-
cle): Description of alternative crystal form for 3. Schematic depic-
tion of dissociative and nondissociative pathways for isomerisation
Table 3. Crystal data and experimental details for 2 and 3.
Compound
2
3
Formula
Mr
C50H28O22Os6P2S·0.6CH2Cl2
2265.88
CH38H28O10Os3P2S·0.9CH2Cl2
1387.34
T [K]
λ [Å]
293(2)
0.71073
293(2)
0.71073
Crystal symmetry
Space group
a [Å]
b [Å]
c [Å]
monoclinic
P21/a (no. 14)
15.694(8)
13.804(5)
28.955(9)
99.98(3)
6178(4)
4
orthorhombic
P212121 (no.19)
11.824(1)
16.945(1)
21.635(1)
90
4334.7(5)
4
2.126
β (°)
V [Å3]
Z
Dcalcd. [Mgm–3]
μ(Mo-Kα) [mm–1]
F(000)
2.4360
12.502
4120
9.061
2595
Crystal size [mm]
θ limits [°]
0.07ϫ0.12ϫ0.20
2–25
10731 [Ϯh, +k, +l]
10722 [R(int) 0.00]
0.15ϫ0.30ϫ0.42
1.5–30
59329 [Ϯh, Ϯk, Ϯl]
10518 [R(int) 0.07]
Reflections collected
Unique observed reflections
[Fo Ͼ 4σ(Fo)]
GoF on F2
1.051
0.0309, 0.0636
1.68 and –1.40
0.90
0.0264, 0.0503
1.12 and –0.97
R1 (F)[a], wR2 (F2)[b]
Largest diff. peak and hole [eÅ–3]
[a] R1 = Σ||Fo| – |Fc||/Σ|Fo|. [b] wR2 = [Σw(F2o – Fc2)2/Σw(F2o)2]1/2 in which w = 1/[σ2(F2o) + (aP)2 + bP] in which P = (F2o + 2F2c)/3.
Eur. J. Inorg. Chem. 2013, 2447–2459
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FULL PAPER
2009, 362, 5175; h) S. Ghosh, G. Hogarth, D. A. Tocher, E.
Nordlander, S. E. Kabir, Inorg. Chim. Acta 2010, 363, 1611.
[15] a) R. Persson, M. Monari, R. Gobetto, A. Russo, S. Aime,
M. J. Calhorda, E. Nordlander, Organometallics 2001, 20, 4150;
b) R. Persson, M. J. Stchedroff, B. Uebersezig, R. Gobetto,
J. W. Steed, P. D. Prince, M. Monari, E. Nordlander, Organo-
metallics 2010, 29, 2223; c) D. A. Hrovat, E. Nordlander, M. G.
Richmond, Organometallics 2012, 31, 6608.
[16] a) G. Schwarzenbach, Chem. Zvesti 1965, 19, 200; b) B. D.
Steffey, A. Miedaner, M. L. Maciejewski-Farmer, Organometal-
lics 1994, 13, 4844; c) G. Degischer, G. Schwarzenbach, Helv.
Chim. Acta 1966, 49, 1927; d) G. Degischer, Ph. D. Thesis,
ETH, Zürich, 1968; e) L. Fälth, Ph. D. Thesis, Lund Univer-
sity, 1976; f) G. I. Bertinsson, Ph. D Thesis, Lund University,
1982; g) A. Cassel, Ph. D. Thesis, Lund University, 1979.
[17] P. A. Dawson, B. F. G. Johnson, J. Lewis, J. Puga, P. R.
Raithby, M. J. Rosales, J. Chem. Soc., Dalton Trans. 1982, 233.
[18] B. F. G. Johnson, J. Lewis, D. A. Pippard, J. Chem. Soc., Dal-
ton Trans. 1981, 407.
of cluster 4b to 4a. Atomic coordinates and energies for the geome-
try-optimised structures of clusters 4a and 4b. These materials are
available upon request from M. G. R.
Acknowledgments
M. M. wishes to thank the University of Bologna and Ministero
dell’Università e della Ricerca (MIUR) (PRIN 2008) for financial
support. M. G. R acknowledges support from the Robert A. Welch
Foundation (grant number B-1093-MGR) and National Science
Foundation (NSF) (CHE-0741936). The authors thank Prof. Car-
laxel Andersson for a generous gift of PSP, Prof. Silvio Aime for
the use of the DRX600 NMR spectrometer in Ivrea, Italy and Dr.
Karl-Erik Bergquist for the use of the DRX500 NMR spectrometer
at Lund University. The authors thank Dr. Håkan Carlsson for
useful suggestions for the synthesis of PSP. The authors also thank
Prof. Michael B. Hall (TAMU) for providing us a copy of his
JIMP2 program, which was used to prepare the geometry-op-
timised structures reported here.
[19] a) D. H. Brown, R. J. Cross, D. J. Millington, J. Chem. Soc.,
Dalton Trans. 1976, 334; b) D. L. DuBois, W. H. Myers, D. W.
Meek, J. Chem. Soc., Dalton Trans. 1975, 101.
[20] A. J. Deeming, S. Donovan-Mtunzi, S. E. Kabir, J. Organomet.
Chem. 1987, 333, 253.
[21] M. J. Stchedroff, S. Aime, R. Gobetto, L. Salassa, E. Nord-
lander, Magn. Res. Chem. 2002, 40, 107.
[22] B. F. G. Johnson, B. E. Reichert, K. T. Schorpp, J. Chem. Soc.,
Dalton Trans. 1976, 1403.
[23] R. F. Alex, R. K. Pomeroy, Organometallics 1987, 6, 2437.
[24] K. Biradha, V. M. Hansen, W. K. Leong, R. K. Pomeroy, J.
Zaworotko, J. Cluster Sci. 2000, 11, 285, and references therein.
[1] a) M. P. Brown, P. A. Bolby, M. M. Harding, A. J. Mathews,
A. K. Smith, J. Chem. Soc., Dalton Trans. 1993, 1671; b) A. W.
Coleman, D. F. Jones, P. H. Dixneuf, C. Brisson, J. J. Bonnet,
G. Lavigne, Inorg. Chem. 1984, 23, 952.
[2] B. F. G. Johnson, J. Lewis, M. Monari, D. Braga, F. Grepioni,
C. Gradella, J. Chem. Soc., Dalton Trans. 1990, 2863.
[3] a) S. Cartwright, J. A. Clucas, R. H. Dawson, D. F. Foster,
M. M. Harding, A. K. Smith, J. Organomet. Chem. 1986, 302,
403; b) E. R. Corey, L. F. Dahl, Inorg. Chem. 1962, 1, 521; c)
J. A. Clucas, D. F. Foster, M. M. Harding, A. K. Smith, J.
Chem. Soc., Chem. Commun. 1984, 949.
[4] B. F. G. Johnson, J. Chem. Soc., Chem. Commun. 1976, 211.
[5] D. F. Foster, J. Harrison, B. S. Nicholls, A. K. Smith, J. Or-
ganomet. Chem. 1985, 295, 99.
[6] J. A. Clucas, M. M. Harding, A. K. Smith, J. Chem. Soc.,
Chem. Commun. 1985, 1280.
[7] S. R. Hodge, B. F. G. Johnson, J. Lewis, P. R. Raithby, J. Chem.
Soc., Dalton Trans. 1987, 931.
[8] a) A. J. Deeming, S. Donovan-Mtunzi, S. E. Kabir, J. Or-
ganomet. Chem. 1984, 276, C65; b) A. J. Deeming, K. I. Hardc-
astle, S. E. Kabir, J. Chem. Soc., Dalton Trans. 1988, 827; c)
A. J. Deeming, S. E. Kabir, J. Organomet. Chem. 1988, 340,
359.
[25]
A. J. Deeming, in: Comprehensive Organometallic Chemistry II
(Eds.: E. W. Abel, F. G. A. Stone, G. Wilkinson), Elsevier, Ox-
ford, UK, 1995, vol. 7, pp. 683–746.
[26]
[27]
M. I. Bruce, T. W. Hambley, B. K. Nicholson, M. R. Snow, J.
Organomet. Chem. 1982, 235, 83.
S. G. Ang, X. Zhong, H. G. Ang, J. Chem. Soc., Dalton Trans.
2001, 1151.
[28]
[29]
S. G. Ang, X. Zhong, H. G. Ang, Inorg. Chem. 2002, 41, 3791.
a) M. I. Bruce, M. J. Liddell, C. A. Hughes, B. W. Skelton,
A. H. White, J. Organomet. Chem. 1988, 347, 157; b) M. I.
Bruce, J. M. Addick, C. A. Hughes, J. A. Patrick, B. W. Skel-
ton, A. H. White, J. Organomet. Chem. 1988, 347, 181; c) M. I.
Bruce, M. J. Lidell, O. Bin Shawkataly, C. A. Hughes, B. W.
Skelton, A. H. White, J. Organomet. Chem. 1988, 347, 207.
M. R. Churchill, B. G. DeBoer, Inorg. Chem. 1977, 16, 878.
a) A. J. Deeming, S. Donovan-Mtunzi, K. I. Hardcastle, S. E.
Kabir, K. Henrick, M. J. McPartlin, J. Chem. Soc., Dalton
Trans. 1988, 579; b) S. E. Kabir, A. Miah, L. Nesa, K. Uddin,
K. I. Hardcastle, E. Rosenberg, A. J. Deeming, J. Organomet.
Chem. 1995, 492, 41; c) K. A. Azam, M. B. Hursthouse, S. E.
Kabir, K. M. Abdul Malik, A. Mottalib, J. Chem. Crystallogr.
1999, 29, 813.
[30]
[31]
[9] S. E. Kabir, A. Miah, L. Nesa, K. Uddin, K. I. Hardcastle, E.
Rosenberg, A. J. Deeming, J. Organomet. Chem. 1995, 492, 41.
[10] P. E. Garrou, Chem. Rev. 1981, 81, 229.
[11] E. Hauptman, P. J. Fagan, W. Marshall, Organometallics 1999,
18, 2061, and references therein.
[12] J. R. Dilworth, N. Wheatley, Coord. Chem. Rev. 2000, 199, 89.
[13] A. J. Deeming, S. N. Jayasuriya, A. J. Arce, Y. De Sanctis, Or-
ganometallics 1996, 15, 786.
[32]
[33]
R. E. Benfield, B. F. G. Johnson, J. Chem. Soc., Dalton Trans.
1980, 1743.
M. R. Churchill, F. J. Hollander, J. P. Hutchinson, Inorg. Chem.
1977, 16, 2655.
[14] a) J. D. King, M. Monari, E. Nordlander, J. Organomet. Chem.
1999, 573, 272; b) S. P. Tunik, I. O. Koshevoy, A. J. Poe, D. H.
Farrar, E. Nordlander, T. A. Pakkanen, M. Haukka, Dalton
Trans. 2003, 2457; c) N. K. Kiriakidou Kazemifar, M. J.
Stchedroff, M. A. Mottalib, S. Selva, M. Monari, E. Nord-
lander, Eur. J. Inorg. Chem. 2006, 2058; d) M. A. Mottalib,
S. E. Kabir, D. A. Tocher, A. J. Deeming, E. Nordlander, J. Or-
ganomet. Chem. 2007, 692, 5007; e) M. N. Uddin, N. Begum,
M. R. Hassan, G. Hogarth, S. E. Kabir, M. Arzu Miah, E.
Nordlander, D. A. Tocher, Dalton Trans. 2008, 6219; f) M. N.
Uddin, M. A. Mottalib, N. Begum, S. Ghosh, A. K. Raha,
D. T. Haworth, S. V. Lindeman, T. A. Siddiquee, D. W. Bennett,
G. Hogarth, E. Nordlander, S. E. Kabir, Organometallics 2009,
28, 1514; g) S. Ghosh, A. K. Das, N. Begum, D. T. Haworth,
S. V. Lindeman, J. F. Gardinier, T. A. Siddiquee, D. W. Bennett,
E. Nordlander, G. Hogarth, S. E. Kabir, Inorg. Chim. Acta
[34]
[35]
J. W. Lauher, J. Am. Chem. Soc. 1986, 108, 1521.
W. H. Watson, G. Wu, M. G. Richmond, Organometallics 2006,
25, 930.
[36]
[37]
[38]
W. H. Watson, G. Wu, M. G. Richmond, Organometallics 2005,
24, 5431.
W. H. Watson, B. Poola, M. G. Richmond, J. Organomet.
Chem. 2006, 691, 4676.
X. Zhang, S. Kandala, L. Yang, W. H. Watson, X. Wang, D. A.
Hrovat, W. T. Borden, M. G. Richmond, Organometallics 2011,
30, 1253.
[39]
a) M. R. Churchill, R. A. Lashewycz, S. I. Richter, J. R.
Shapley, Inorg. Chem. 1980, 19, 1277; b) J. Puga, A. Arce, D.
Braga, N. Centritto, F. Grepioni, R. Castillo, J. Ascanio, Inorg.
Eur. J. Inorg. Chem. 2013, 2447–2459
2458
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www.eurjic.org
FULL PAPER
Chem. 1987, 26, 867; c) P. Homanen, R. Persson, M. Haukka,
T. A. Pakkanen, E. Nordlander, Organometallics 2000, 19,
5568.
[44]
a) JIMP2, v. 0.091, a free program for the visualization and
manipulation of molecules: M. B. Hall, R. F. Fenske, Inorg.
Chem. 1972, 11, 768; b) J. Manson, C. E. Webster, M. B. Hall,
Texas A&M University, College Station, TX, 2006: http://
www.chem.tamu.edu/jimp2/index.html.
[40] T. F. Doumani, Patent no: 2,532,612, 1945, United States
Patent Office, USA.
[41] M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria,
M. A. Robb, J. R. Cheeseman, G. Scalmani, V. Barone, B.
Mennucci, G. A. Petersson, H. Nakatsuji, M. Caricato, X. Li,
H. P. Hratchian, A. F. Izmaylov, J. Bloino, G. Zheng, J. L. Son-
nenberg, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hase-
gawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai,
T. Vreven, J. A. Montgomery, Jr., J. E. Peralta, F. Ogliaro, M.
Bearpark, J. J. Heyd, E. Brothers, K. N. Kudin, V. N. Starov-
erov, R. Kobayashi, J. Normand, K. Raghavachari, A. Rendell,
J. C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, N. Rega, J. M.
Millam, M. Klene, J. E. Knox, J. B. Cross, V. Bakken, C. Ad-
amo, J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev,
A. J. Austin, R. Cammi, C. Pomelli, J. W. Ochterski, R. L. Mar-
tin, K. Morokuma, V. G. Zakrzewski, G. A. Voth, P. Salvador,
J. J. Dannenberg, S. Dapprich, A. D. Daniels, O. Farkas, J. B.
Foresman, J. V. Ortiz, J. Cioslowski, D. J. Fox, Gaussian 09, Re-
vision A.02, Gaussian, Inc., Wallingford, CT, 2009.
[45]
A. C. T. North, D. C. Phillips, F. S. Mathews, Acta Crystallogr.,
Sect. A: Cryst. Phys. Diffr., Theor. Gen. Crystallogr. 1968, 24,
351.
G. M. Sheldrick, SHELXS 97, Program for crystal structure
solution, University of Göttingen, Germany, 1997.
[46]
[47]
G. M. Sheldrick, SHELXL-97, Program for crystal structure re-
finement, University of Göttingen, Germany, 1997.
[48] G. M. Sheldrick, SADABS, Program for empirical absorption
correction, University of Göttingen, Germany, 1996.
[49] SIR97, A new tool for crystal structure determination and refine-
ment: A. Altomare, M. C. Burla, M. Camalli, G. L. Cascarano,
C. Giacovazzo, A. Guagliardi, A. G. G. Moliterni, G. R. Poli-
dori Spagna, J. Appl. Crystallogr. 1999, 32, 115.
[50] G. M. Sheldrick, SHELXTLplus, v. 5.1 (Windows® NT ver-
sion), Structure Determination Package, Bruker Analytical X-
ray Instruments Inc., Madison, WI, USA, 1998.
Received: November 19, 2012
Published Online: March 1, 2013
[42] A. D. Becke, J. Chem. Phys. 1993, 98, 5648.
[43] C. Lee, W. Yang, R. G. Parr, Phys. Rev. B 1988, 37, 785.
Eur. J. Inorg. Chem. 2013, 2447–2459
2459
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