The first alkynethiolate derivatives of bis(substituted cyclopentadienyl)titanium(IV) and their role in the synthesis of heterobimetallic compounds. Crystal structures of

Article abstract of DOI:10.1039/a803806f

The first thioalkyne derivatives of functionalised titanocene of formula [Ti(η⁵-C₅H₄R′)(η ⁵-C₅H₄R″)(SO≡CR)₂] (R = Bu^t, R′ = R″ = SiMe₃ 1a; R = Ph, R′ = R′ =

Full text of DOI:10.1039/a803806f

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The first alkynethiolate derivatives of bis(substituted cyclopenta-
dienyl)titanium(IV) and their role in the synthesis of heterobimetallic
5
t
᎐
compounds. Crystal structures of [Ti(ç -C H SiMe ) (SC᎐CBu ) ]
᎐
5
4
3 2
2
5
t
5
t
᎐
᎐
and[(ç -C H SiMe )(SC᎐CBu )Ti(ì-ç :ê-P-C H PPh )(ì-SC᎐CBu )-
᎐
᎐
5
4
3
5
4
2
Pt(C6F5)2]†
Irene Ara,a Esther Delgado,*b Juan Forniés,a Elisa Hernández, Elena Lalinde,*c
Noelia Mansillab and M. Teresa Morenoc
a Departamento de Química Inorgánica, Instituto de Ciencia de Materiales de Aragón,
Universidad de Zaragoza-C.S.I.C., 50009 Zaragoza, Spain
b Departamento de Química Inorgánica, Facultad de Ciencias, Universidad Autónoma de
Madrid, 28049 Madrid, Spain. E-mail: esther.delgado@aumam.es
c Departamento de Química, Universidad de la Rioja, 26001 Logroño, Spain
Received 20th May 1998, Accepted 13th July 1998
5
5
᎐
The first thioalkyne derivatives of functionalised titanocene of formula [Ti(η -C H RЈ)(η -C H RЉ)(SC᎐CR) ]
᎐
5
4
5
4
2
(R = But, RЈ = RЉ = SiMe3 1a; R = Ph, RЈ = RЉ = SiMe3 1b; R = But, RЈ = SiMe3, RЉ = PPh2 2a; R = But, RЈ =
5
5
᎐
RЉ = PPh 3a) have been prepared by reaction of [Ti(η -C H RЈ)(η -C H RЉ)Cl ] and LiSC᎐CR in diethyl ether.
᎐
2
5
4
5
4
2
Complexes 1a and 2a have been used as precursors in the synthesis of Ti–M (M = d6 or d8 metal) heteronuclear
complexes showing different co-ordination modes. All compounds have been characterised by elemental analysis and
1H, 31P, 19F and 13C NMR and infrared spectroscopy. The crystal structures of two complexes have been solved.
S
S
Introduction
C
C
The synthesis and study of early–late heterobimetallic
compounds is an active subject of research in organometallic
chemistry.1 One of the reasons for this interest is related to
some catalytic processes in view of the potential of this type of
compound to promote activation of small molecules (e.g. CO).2
Owing to the propensity of sulfur to form M(µ-SR)MЈ bridges,
an appropriate synthetic pathway to such species consists
on the use of thiolate derivatives of group 4 metallocenes as
metalloligands. Stephan and co-workers3 have made an
important contribution in this area by using different thiolate
derivatives of titanocene in their reactions with d10 transition
metal species. In the last years we have studied the reactions
between d6 and d8 metal fragments and [Ti(η5-C5H4R)2(SRЈ)2]
(R = H, SiMe3 or PPh2; RЈ = aryl or alkyl group), yielding
bi- and tri-nuclear compounds stabilised by double homo
(µ-η5 :κ-P-C5H4PPh2)2 and (µ-SR)2 or hetero (µ-η5 :κ-P-
C5H4PPh2)(µ-SR) bridging systems.4
M
S
C
C
M
C
M
C
Ph
Ph
R
η1-(S)
η1-(C)
η2-(C,C)
M = Pt, Ru
Ru
Mo, W
R
C
C
S
M
M'
On the other hand, the ability of alkynyl ligands to bind
several metal centres through σ and π bonds is now firmly
established.5 In particular in this area we and others have also
reported the synthesis of different early–late binuclear doubly
alkynyl bridged complexes.6,8 These complexes have been
µ-(S,S)
Fe
Scheme 1
studied in order to gain understanding of the factors that
instance, Weigand et al. have reported9 not only the syntheses
᎐
govern the preferred geometries of the C᎐C groups because of
᎐
of several alkyne thiolate mononuclear complexes of RuII and
their relevance in C–C coupling alkynide processes,7 as well as
PtII with these ligands acting as η1-(S) bonded ligands
C–C bond cleavage on butadiynes.8
᎐
(M–SC᎐CRЈ), but also the ability of the phenylalkynethiolate
᎐
By contrast with the amount of work devoted to thiolate and
alkynide bridged heterobimetallics and their mononuclear
precursors, reports on related alkynethiolates are exceedingly
rare. Interestingly the few examples that have been published
show a quite versatile co-ordination behaviour (Scheme 1). For
to act as an η1-(C) bonded thioketenyl, [Ru]᎐C(Ph)–C᎐S,
᎐
᎐
terminal group.9a Recently, the co-ordination as an alkyne thio-
ketenyl η2-(C,C) with the ligand acting as a three electron donor
has been also demonstrated,10 but, as far as we are aware, only a
᎐
᎐
diiron carbonyl complex [Fe (CO) (µ-C᎐CPh)(µ-SC᎐CPh)] con-
᎐
᎐
2
6
taining a sulfur alkynethiolate bridging group µ-(S,S) has been
† Dedicated to Professor Pascual Royo on the occasion of his 60th
birthday.
reported.11 In the context of these groups it should be noted
J. Chem. Soc., Dalton Trans., 1998, 3199–3208
3199

View Article Online
that some additional work has been developed with the iso-
12
᎐
meric thioacetylide ligands C᎐CSR.
᎐
In this paper we report on the preparation and properties of
several mononuclear alkynethiolate titanocene complexes
᎐
[Ti(C H RЈ)(C H RЉ)(SC᎐CR) ] 1–3 and describe their re-
᎐
5
4
5
4
2
activity towards several d6 [Mo(CO)4(nbd)] and [Mo(CO)3-
(NCMe)3] and d8 cis-[M(C6F5)2(thf)2] (M = Pt or Pd) metal
complexes containing labile ligands. The syntheses of homo
bis(µ-alkynethiolate) 4a–6b and hetero bis(µ-alkynethiolate,
µ-cyclopentadienyldiphenylphosphine) bridged derivatives 7,
5
᎐
8, 9 and the solid-state structures of [Ti(η -C H SiMe ) (SC᎐
᎐
5
4
3 2
t
5
t
5
᎐
CBu ) ] 1a and [(η -C H SiMe )(SC᎐CBu )Ti(µ-η :κ-P-C H -
᎐
2
5
4
3
5
4
t
᎐
PPh )(µ-SC᎐CBu )Pt(C F ) ] 8 are presented.
᎐
2
6
5 2
Results and discussion
Mononuclear derivatives
The formation of metallocene alkynethiolate titanium()
5
5
᎐
derivatives [Ti(η -C H RЈ)(η -C H RЉ)(SC᎐CR) ] 1a–3a was
5
t
᎐
5
4
5
4
2
᎐
Fig. 1 View of molecular structure of [Ti(η -C5H4SiMe3)2(SC᎐CBu )2]
᎐
accomplished by treatment of [Ti(η5-C5H4RЈ)(η5-C5H4RЉ)Cl2]
(RЈ = RЉ = SiMe3; RЈ = SiMe3, RЉ = PPh2, RЈ = RЉ = PPh2) with
lithium alkynethiolate reagents LiSC᎐CR (2 equivalents) at
1a.
13
᎐
᎐
Table 1 Selected bond lengths (Å) and angles (Њ) of complex 1a
very low temperature (Ϫ70 ЊC) in diethyl ether [eqn. (1)]. After
(molecule 1)
R'
Ti
R'
Ti
Ti(1)–S(1)
Ti(1)–S(2)
S(1)–C(17)
S(2)–C(23)
2.451(4)
2.451(4)
1.688(11)
1.712(12)
C(17)–C(18)
C(23)–C(24)
Ti(1)–cent(1)
Ti(1)–cent(2)
1.174(13)
1.144(14)
2.050
SC CR
SC CR
Cl
Cl
Et2O
-70 o
(1)
+
2
RC CSLi
C
2.038
R''
R''
S(2)–Ti(1)–S(1)
cent(1)–Ti(1)–cent(2) 130.9
S(2)–C(23)–C(24)
Ti(1)–S(1)–C(17)
92.30(13)
S(1)–C(17)–C(18)
C(17)–C(18)–C(19)
C(23)–C(24)–C(25)
Ti(1)–S(2)–C(23)
177.5(12)
173.3(13)
169(2)
R'
R"
R
174.0(13)
107.7(4)
1a SiMe3 SiMe3 But
1b SiMe3 SiMe3 Ph
114.2(3)
2a SiMe3 PPh2
3a PPh2 PPh2
But
But
resonances which appear in the expected range. Particularly
evident are the acetylenic carbon resonances (δ 80.8, 117.5 1a;
93.0, 107.3 1b; 80.2, 117.8 2a) which occur in a similar region
to that previously reported for other η1-(S) bonded alkyne-
conventional work-up complexes 1–3 were isolated as green
microcrystalline solids and their spectroscopic (IR, 1H, 13C
and 31P NMR) and analytical data unequivocally confirm
the structural proposal shown in eqn. (1) with the alkynethio-
late ligands η1-(S) bonded. Further confirmation was obtained
from the X-ray diffraction study of compound 1a.
9
6,8
᎐
᎐
thiolate (M–SC᎐CR) or alkynyl (M–C᎐CR) compounds.
᎐
᎐
Complexes 1a and 1b show only three cyclopentadienyl carbon
resonances while the mixed derivative [Ti(η5-C5H4SiMe3)-
5
t
᎐
(η -C H PPh )(SC᎐CBu ) ] 2a exhibits five resonances for
᎐
5
4
2
2
It should be noted that initial attempts to carry out the
former reaction at room temperature, following similar reaction
conditions to those reported for ruthenium() and platinum()
complexes,9 failed to yield the alkynethiolate derivatives.
The substitution of SiMe3 by PPh2 groups on the cyclopenta-
dienyl rings reduces considerably the stability of these systems.
Thus, whereas complexes 1a,1b and 2a show satisfactory
elemental analysis, the instability of 3a in solution and in
the solid state precludes a good analysis. In the same line we
have previously shown that the stability of mixed [Ti(η5-C5-
H4SiMe3)(η5-C5H4PPh2)X2] (X = Cl or SPh) derivatives is con-
siderably higher than that of analogous [Ti(η5-C5H4PPh2)2X2].14
The most noticeable fact in the IR spectra of complexes 1–3
each substituted C5H4 ring suggesting that the five carbon
atoms are inequivalent probably due to molecular steric
strains. The shielding of the 31P resonances displayed by com-
plexes 2a (δ Ϫ15.2) and 3a (δ Ϫ15.5) is typical of this type
of compound.4a
5
t
᎐
Crystal structure of [Ti(ç -C H SiMe ) (SC᎐CBu ) ] 1a
᎐
5
4
3
2
2
This compound crystallises with two crystallographically
independent molecules, which have essentially the same
structure, in the asymmetric unit. Discussion will therefore be
limited to only one of them. The monomeric structure of 1a
is shown in Fig. 1 and selected bond distances and angles
are listed in Table 1. The compound shows a distorted tetra-
hedral arrangement around the titanium atom made up of
the two centroids of trimethylsilylcyclopentadienyl rings,
which adopt a staggered disposition, and the two thiolate
ligands. The S(1)–Ti(1)–S(2) angle of 92.30(13)Њ as well as the
Ti(1)–S(1,2) [2.451(4) Å], Ti(1)–centroid(1) [2.050(2) Å] and
Ti(1)–centroid(2) [2.038(3) Å] distances are in the range
reported for analogous compounds [Ti{η5-C5H4P(S)Ph2}2-
(SPh)2],14b [Ti(η5-C5H4SiMe3)2(SC6F5)2]14a and [Ti(η5-C5H5)2-
(SMe)2].3e Once again the endo (anti) conformation shown by
this titanium() derivative confirms the relationship between
is the presence of a weak absorption in the 2129–2145 cmϪ1
᎐
region corresponding to the C᎐C stretching mode, clearly
᎐
indicating that the acetylenic fragments are not involved in
co-ordination. Their NMR data (1H and 13C) indicate that
only one of the two expected isomers (syn or anti) is present in
solution (see Experimental section). In the 1H NMR spectra the
resonances due to cyclopentadienyl protons, two for 1a, 1b and
3a (δ 6.40–6.62, 6.01–6.53) and four for complex 2a (6.54, 6.38,
6.34, 6.11) due to the presence of two different substituted
rings, are shifted upfield in relation to the dichloride starting
precursors. This effect can be accounted for the lowering in the
electronegativity on going from the chloride to the alkyne-
thiolate ligand. As expected, singlet signals are observed for
the But or SiMe3 groups in all complexes. The presence of
these groups is also confirmed by their characteristic 13C NMR
the type of isomer and the S(1)–Ti–S(2) angle. The bond
᎐
lengths S–C [1.688(11), 1.712(12) Å] and C᎐C [1.174(13),
᎐
1.144(14) Å] and angles Ti–S–C [107.4(7), 114.2(3)], S–C–C
[177.5(12), 174.0(12)] and C–C–C [173.3(13), 169(2)] found
3200
J. Chem. Soc., Dalton Trans., 1998, 3199–3208

View Article Online
within the alkynethiolate fragments show no unusual features,
extremely soluble even in hydrocarbon solvents such as n-
being quite similar to those found in complexes [Pt(PPh3)2-
hexane, pentane or n-heptane. In spite of many attempts we
have not been able to obtain suitable crystals for X-ray analysis
of any of these dinuclear compounds 4–6, however their
9b
{SC᎐CC(Me)} ] and [Fe (CO) (µ-C᎐CPh)(µ-SC᎐Ph)]11 which
᎐
᎐
᎐
᎐
᎐
᎐
2
2
6
to our knowledge are the only examples of thioalkyne deriva-
tives of transition metals structurally characterised.
spectroscopic data are consistent with the S,S co-ordination
᎐
mode of the difunctional metallocene [Ti](SC᎐CR) chelating
᎐
2
᎐
ligands. Thus, their IR spectra show a medium ν(C᎐C) absorp-
᎐
Heterobinuclear derivatives
tion in the characteristic region of non-co-ordinated alkynes.13b
We have previously shown that titanocene thiolate derivatives
[Ti(η5-C5H4RЈ)2(SR)2] (RЈ = H, SiMe3 or PPh2) can act as either
bi- [RЈ = H or SiMe3(S,S), PPh2(P,P)] or tetra-dentate [RЈ =
PPh2, bis(P,S) or P,P; S,S] ligands towards the d6 Mo(CO)4
and d8 M(C6F5)2 (M = Pd or Pt) metal fragments.4 The sub-
stitution of arene- or alkene-thiolates by alkynethiolates on the
mononuclear titanocene supplies an additional co-ordination
position. We have reported several examples illustrating the
ability of bis(alkynyl) transition metal complexes [MЈLn-
Compared with the precursors (1a 2129 cmϪ1 and 1b 2134 cmϪ1
)
᎐
the stretching frequency ν(C᎐C) for 5 and 6 is shifted to higher
᎐
wavenumbers (2168 5a, 2165, 5b, 6b; 2166 cmϪ1 6a) suggesting
that co-ordination of the sulfur lone pair to platinum or
palladium probably reduces sulfur π-donor interactions with
the acetylenic fragment. In marked contrast the solution
᎐
IR spectrum of the Mo–Ti complex 4a shows the ν(C᎐C)
᎐
at 2072 cmϪ1. The relative lowering of ν(C᎐C) (≈57 cmϪ1) is
᎐
᎐
considerably smaller than those previously reported for co-
15a–d
2
Ir15e or Ti6a) to bond “cis-M(C6F5)2”
ordinated thioalkynes,16 i.e. [S{(η -C᎐CPh)Co (CO) } ]16a 1592
᎐
᎐
(C᎐CR) ] (MЈ = Pt,
᎐
᎐
2
2
6 2
(M = Pt or Pd) metal fragments through η2-acetylenic bonding
interactions. Therefore, we considered it of interest to explore
the reactivity of the novel bis(alkynethiolate) derivatives
1–3 towards the same substrates: [Mo(CO)4(nbd)] and cis-
[M(C6F5)2(thf)2] (M = Pt or Pd, thf = tetrahydrofuran),
respectively.
vs. S(C᎐CPh) 2180 cmϪ1 and [{Cu(O SCF ) S(C᎐CBu ) ]
t
16b
᎐
᎐
᎐
᎐
2
3
3
2
2
1988 vs. S(C᎐CBu ) 2200 cmϪ1, suggesting that acetylenic
t
᎐
᎐
2
fragments are not co-ordinated to Mo. The NMR data are
consistent with the presence of the dinuclear species in the two
isomeric forms syn and anti shown in Scheme 2. This structural
feature, which arises from the relative orientation of the alkyne
groups on the sulfur atoms, is not unusual and in many cases
equilibrium studies find the two conformers to be of similar
thermodynamic stability. In fact, a few [(η5-C5H5)2Ti(µ-SR)2-
Mo(CO)4] compounds have been reported as endo (anti/syn)
stereochemically non-rigid mixtures in solution.17 We have
previously found that the heterobimetallic Ti–Pt and Ti–Pd
[(η5-C5H4RЈ)2Ti(µ-SR)2M(C6F5)2] (M = Pt or Pd, RЈ = H or
SiMe3, R = Ph or C6F5) systems adopt both in the solid state
(X-ray; M = Pd, RЈ = SiMe3, R = Ph) and in solution an endo
(syn) arrangement with respect to the central TiS2M core.4b The
higher preference for the anti isomer found for these Ti–M
mixed derivatives, related to the ones mentioned before, could
be attributed to the bulkiness of the alkyne fragment on these
The results of this study are summarised in Scheme 2.
5
᎐
Treatment of [Ti(η -C H SiMe ) (SC᎐CR) ] with either
᎐
5
4
3
2
2
[Mo(CO)4(nbd)] (excess) or cis-[M(C6F5)2(thf)2] (1 equivalent)
in toluene at room temperature (for 1a and M = Pt in CH2Cl2)
results in the formation of neutral bis(thiolato)bridged
5
᎐
heterobinuclear complexes [(η -C H SiMe ) Ti(µ-SC᎐CR) -
᎐
5
4
3
2
2
MLn] [MLn = Mo(CO)4 4a, Pt(C6F5)2 5a, 5b, or Pd(C6F5)2 6a,
6b] in moderate to high yield (60% 4a–88% 6b). Complex 4a is
isolated as a green solid after chromatographic purification.
Complexes 5a (orange) and 6b (red-garnet) are precipitated as
solids by treatment of the residues with n-heptane and n-hexane
respectively, while 5b and 6a can be isolated as orange solids
only by removing the solvent. These latter compounds are
But
But
But
C
CO
C
C
Ph
OC
CO
C
C
Ph
CO
S
CO
CO
P
Mo CO
S
C
CO
CO
SiMe3
Ti
SiMe3
+
Mo
CO
SiMe3
Ti
SiMe3
Mo
CO
S
Ti
S
C
(iii)
(i)
C
SiMe3
But
4a ratio syn:anti 1:1
R'
Ti
7
CR
R''
(ii)
(iv)
C
CR
S
C6F5
C6F5
CR
C
Ph
P
SiMe3
+
Ti
M
S
C6F5
C6F5
Ph
C
C6F5
C6F5
S
SiMe3
Ti
SiMe3
M
SiMe3
M
Ti
SiMe3
S
C
CR
R
ratio syn:anti
M
M=Pt
8
5a But
5b Ph
6a But
6b Ph
0.9:1
1:1
M=Pd 9
Pt
Pt
Pd
Pd
5:1
10:1
Scheme 2 (i) [Mo(CO)3(NCMe)3], toluene, room temperature (r.t.); (ii) [M(C6F5)2(thf)2] (M = Pt or Pd), toluene, Ϫ20 ЊC; (iii) [Mo(CO)4(nbd)],
toluene, r.t.; (iv) [M(C6F5)2(thf)2] (M = Pt or Pd), toluene, r.t. (for 5a, CH2Cl2).
J. Chem. Soc., Dalton Trans., 1998, 3199–3208
3201

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᎐
µ-SC᎐CR bridging ligands. Similar steric considerations have
᎐
previously been suggested to rationalise the shift of the equi-
librium in favour of the anti isomer.18 The preference for the
syn isomer is slightly higher for the phenyl derivatives 6b and
5b than for the tert-butyl complexes 6a and 5a respectively.
The reason for the fact that the syn conformation seems to be
more thermodynamically favoured on palladium than platinum
mixed-metal complexes is less clear.
According to the presence of an ≈1:1 syn:anti mixture, the
Ti–Mo complex 4a exhibits in its proton spectrum two singlet
resonances (δ 1.23, 1.20) due to But groups and, at high field,
two signals of equal intensity (δ 0.44, 0.33) assigned to the non-
equivalent SiMe3 groups in the syn isomer and, a more intense
signal at δ 0.39 which belongs to the equivalent SiMe3 groups in
the anti isomer. The expected three distinct cyclopentadienyl
sets of resonances are observed slightly upfield shifted (δ 6.31–
5.27) with respect to those seen for 1 (δ 6.46, 6.38) indicating
an increase of electron density on the Ti. This spectroscopic
feature has been previously observed in related bis(alkyl)
and aryl bridging thiolate Ti–Mo compounds.17 The proton
spectrum is temperature dependent. Thus, on raising the
temperature all signals broaden, and at ϩ50 ЊC a single sharp
But (δ 1.24) and broad SiMe3 (δ 0.41) resonances are observed
while in the cyclopentadienyl region only two very broad humps
are barely discernible suggesting that both isomers are inter-
converting on the NMR timescale. When the temperature is
lowered the high-field region (But, SiMe3 resonances) does not
change indicating a similar syn:anti ratio (1.1:1) but, however,
the signals in the cyclopentadienyl region clearly broaden. In
the lowest temperature spectrum (Ϫ50 ЊC) ten distinct proton
resonances [δ 6.30 (2 H), 6.22 (2 H), 6.12, 5.84, 5.67 (1 H each),
5.52 (2 H), 5.26 (4 H), 5.12, 4.88, 4.79 (1 H each)] are seen
implying rigid formulations with the lack of a symmetry plane
passing through Ti and Mo atoms at low temperature. This fact
could be tentatively related to hindrance of the rotation of
Fig. 2 Variable temperature 19F NMR spectra (Fortho region) of [(η5-
᎐
C5H4SiMe3)2Ti(µ-SC᎐CPh)2Pd(C6F5)2] 6b (syn and anti).
᎐
Fig. 3 Proton NMR spectra of the complex [(η5-C5H4SiMe3)2Ti(µ-
t
᎐
either the bulky C᎐CBu groups around the C(sp)–S bonds or
᎐
᎐
the substituted η5-C5H4SiMe3 rings.
SC᎐CPh)2Pd(C6F5)2] 6b (syn and anti) at different temperatures.
᎐
As was previously found in related aryl (SPh, SC6F5) thiolate
syn isomers [(η5-C5H4SiMe3)2Ti(µ-SR)2M(C6F5)2] (M = Pt or
Pd), the heterobinuclear Ti–Pt complexes 5 are relatively more
rigid in solution than the Ti–Pd ones 6. Thus, both titanium–
platinum complexes 5 display in their low (Ϫ50 ЊC) and room
temperature (20 ЊC) 19F NMR spectra the expected two differ-
ent sets (AFMRX systems) of rigid C6F5 fluorine resonances
(one set assigned to each isomer), and similar spectra, but
with a less defined pattern, were also observed at the highest
accessible temperature (ϩ50 ЊC). No significant modification
of the ratio of both isomers was observed in the range of
temperature explored. Similar results were observed from
maining signals of lower intensity (δ 6.77, 6.45, 6.21 and 5.92
CH; 0.31 SiMe3) are therefore attributed to the anti isomer.
When the temperature is increased the signals broaden and,
finally, collapse to only two broad ones for the cyclopentadienyl
resonances and one signal for the SiMe3 at ca. ϩ50 ЊC. This
pattern suggests fast interconversion of both isomers on the
NMR timescale at this high temperature. Similar behaviour
was observed for complex 6a, the most remarkable difference
being the different syn:anti (≈5:1) ratio found at low tem-
perature. The 13C NMR spectra of all complexes have also
been recorded (5, 6 at Ϫ50 ЊC, due to their low stability in
solution, and room temperature for 4a, see Experimental
section for data). A syn:anti mixture in approximately the
expected ratio is observed for all complexes, particularly, for
1
the variable-temperature H NMR spectra. Only at high tem-
perature (ϩ50 ЊC) the cyclopentadienyl and SiMe3 (also But
groups for 5a) resonances of both isomers become broad (one
SiMe3 is observed for 5b but coalescence of C5H4 signals is not
reached) suggesting that the rate of interconversion syn–anti
the SiMe3 and But (5a, 6a) resonances. Unfortunately, they are
᎐
not very informative in the C᎐C region. Only for 5b the
᎐
1
is still slow on the NMR timescale. By contrast, the H and
expected four alkyne carbon resonances which appear slightly
upfield shifted in relation to the starting material are clearly
identified. For 6b the acetylenic carbon resonances of the
major isomer (syn) are also shifted (δ 103.5, 81.6 vs. 107.3,
93.0 1b) and, a small signal at δ 99.2 can tentatively assigned
to the minor anti isomer. For the remaining complexes, only
one (4a) or two signals (5a, 6) in the δ 67.78–75.5 range can be
assigned.
19F NMR spectra of the titanium–palladium complexes 6 at
ϩ50 ЊC show the presence of only one set of resonances for
the C6F5, C5H4SiMe3 and But groups (this latter in the case of
6a). Selected ranges of the variable temperature 19F (Fortho) and
1H (C5H4SiMe3) spectra of 6b are shown in Figs. 2 and 3. As
can be observed when the temperature is lowered the broad
Fortho resonance (Fig. 2) is resolved into four distinct resonances
with very different 1:10:10:1 ratio. The signals with lower
intensity which exhibit higher δ(F2), δ(F6) values (at Ϫ50 ЊC,
Ϫ115.8; Ϫ117.6) are unequivocally assigned to the anti isomer
in accordance with the proton data (Fig. 3). The proton
spectrum at low temperature (Ϫ50 ЊC) clearly reveals the
presence of the two non-equivalent C5H4SiMe3 groups, which is
consistent with that expected for the syn isomer (major isomer,
δ 6.81, 6.57, 6.36 and 6.28 CH; δ 0.38, 0.22 SiMe3). The re-
According to previous results4c the preference for co-
ordination through the phosphorus atom is evidenced by using
the mixed-ligand mononuclear complex [Ti(η5-C5H4SiMe3)-
5
t
᎐
(η -C H PPh )(SC᎐CBu ) ] 2a as precursor. Thus (Scheme 2),
᎐
5
4
2
2
by treatment of 2a with [Mo(CO)4(nbd)] in toluene, at room
temperature, a single heterodimetallic complex 7 was obtained
in very low yield (12%). The IR spectrum (toluene solution)
of the isolated material showed, in addition to a band at
3202
J. Chem. Soc., Dalton Trans., 1998, 3199–3208

View Article Online
2070 cmϪ1 assignable to ν(C᎐C), a clear CO 1956vs, 1895m,
᎐
᎐
1879s pattern attributable to a fac-Mo(CO)3 unit suggesting
that the organometallic 2a fragment is acting as a tridentate
(S,S,P) ligand to the Mo. Further evidence follows from the
elemental analysis and the spectroscopic properties. Moreover,
when [Mo(CO)3(NCMe)3] was used instead of [Mo(CO)4(nbd)]
the reaction proceeded, as expected, in a cleaner way and com-
5
5
t
᎐
plex
[(η -C H SiMe )Ti(µ-η :κ-P-C H PPh )(µ-SC᎐CBu ) -
᎐
5 4 3 5 4 2 2
Mo(CO)3] 7 was obtained in a higher yield (53%). A similar
behaviour has recently been observed by us when using related
trifunctional ligand systems [Ti(η5-C5H4SiMe3){η5-C5H4P(E)-
PPh2}(SPh)2] (E = O or S) and [W(CO)4(nbd)2].19 It seems that
the three potential donor atoms (S, S and P) are well suited for
the stabilisation of the fac-Mo(CO)3 fragment. The NMR data
reveal that only one of the two expected isomers (syn and anti)
is present in solution. A syn orientation is tentatively suggested
1
on the basis of the H and 13C NMR spectra which display
t
1
᎐
magnetically equivalent SC᎐CBu ligands. Thus, the H NMR
᎐
5
t
5
᎐
Fig. 4 Molecular structure of [(η -C5H4SiMe3)(SC᎐CBu )Ti(µ-η :κ-P-
᎐
spectrum exhibits, in addition to four cyclopentadienyl proton
resonances at δ 6.23, 5.17 and 5.61, 5.49 assignable to different
C5H4PPh2 and C5H4SiMe3 rings, respectively, a single sharp
But signal at δ 1.20. The SiMe3 protons are observed at δ 0.41. A
similar pattern was observed in the Ϫ50 to ϩ50 ЊC temperature
range, suggesting the absence of any dynamic process. In
the 13C NMR spectrum the proposed formulation is mainly
supported by the observation of only one set of acetylenic
carbon resonances (δ 111.4 and 75.4) and a clear singlet signal
at δ 31.1 due to methyl carbon resonances of the equivalent
But groups. Furthermore, in accordance with the P,S,S, co-
ordination suggested, the 31P NMR spectrum shows the
phosphorus resonances (δ 39.7) strongly shifted to low field
(∆ = ϩ54.9) relative to the starting material (δ Ϫ15.2 2a).
t
᎐
C5H4PPh2)(µ-SC᎐CBu )Pt(C6F5)2] 8.
᎐
Table 2 Selected bond lengths (Å) and angles (Њ) for complex 8
Pt–C(7)
Pt–P(1)
Pt–C(1)
Pt–S(1)
Ti–S(2)
Ti–S(1)
Ti ؒ ؒ ؒ Pt
2.023(13)
2.277(3)
2.039(12)
2.360(3)
2.366(4)
2.532(4)
3.817(3)
S(1)–C(38)
S(2)–C(44)
Ti–cent(1)
Ti–cent(2)
C(38)–C(39)
C(44)–C(45)
1.700(12)
1.668(12)
2.039
2.049
1.19(2)
1.20(2)
C(1)–Pt–P(1)
Ti–S(1)–C(38)
C(1)–Pt–S(1)
C(7)–Pt–S(1)
P(1)–Pt–S(1)
Pt–S(1)–Ti
175.7(4)
106.6(4)
94.5(3)
178.1(4)
83.92(11)
102.51(12)
89.39(12)
111.1(4)
C(39)–C(38)–S(1)
C(38)–C(39)–C(40)
C(45)–C(44)–S(2)
S(1)–Ti–cent(1)
S(1)–Ti–cent(2)
C(7)–Pt–C(1)
175.3(11)
178.2(13)
179.3(11)
102.0
109.7
87.0(5)
Similarly, as shown in Scheme 2, treatment of complex 2a with
1 equivalent of cis-[M(C6F5)2(thf)2] (M = Pt or Pd) in toluene
at low temperature (Ϫ20 ЊC) affords the heterodinuclear
S(2)–Ti–S(1)
Ti–S(2)–C(44)
C(7)–Pt–P(1)
C(44)–C(45)–C(46)
94.6(4)
178.2(13)
5
t
5
᎐
derivatives [(η -C H SiMe )(SC᎐CBu )Ti(µ-η :κ-P-C H PPh )-
᎐
5
4
3
5
4
2
t
᎐
(µ-SC᎐CBu )M(C F ) ] (M = Pt 8 or Pd 9). These complexes,
᎐
6
5 2
isolated as violet microcrystalline solids, are moderately air-
stable in the solid state, but in solution they decompose in a
few hours. The dimetallic formulation with an heteromixed
bridging system is consistent with their spectroscopic data
(IR, NMR) and confirmed by an X-ray diffraction study on the
Ti–Pt complex 8 (see below).
The complex crystallises together with one molecule of toluene
and 0.5 of hexane. Selected bond lengths and angles are
collected in Table 2. The titanium atom is pseudo-tetrahedrally
surrounded by two cyclopentadienyl ligands and the sulfur
t
᎐
atoms of the two SC᎐CBu ligands. The platinum centre
᎐
The presence of non-co-ordinated alkyne fragments is
exhibits a distorted “square-planar” geometry formed by the
inferred from the IR spectra. Thus, both complexes show
Cipso atoms of two mutually cis C6F5 groups, a sulfur atom of
t
᎐
᎐
ν(C᎐C) absorptions assignable to the alkynethiolate ligands
a µ-SC᎐CBu ligand and a phosphorus atom of the bridging
᎐
᎐
which lie approximately in the same region as for the corre-
sponding mononuclear derivative [2157w, 2141m 8; 2158w,
2141m 9 vs. 2145 cmϪ1 2a]. Moreover, co-ordination of the
phosphorus atom is evidenced from their 31P NMR spectra,
which show a singlet resonance (δ 5.14 8, 10.93 9) shifted to
higher frequency relative to that of 2a. For both complexes
the signal is somewhat broad probably due to unresolved long-
range phosphorus–fluorine couplings and, as expected, for 8
the signal is flanked by 195-platinum satellites [1J(Pt–P) = 2361
Hz]. The 1H NMR spectra (at Ϫ50 ЊC and at room tem-
perature) exhibit, in addition to phenyl resonances, two singlets
at δ 1.20, 1.11 for 8 and 1.22, 1.11 for 9 and another singlet
at δ 0.13 due to the methyl moieties of the inequivalent tert-
butylalkynethiolate and free C5H4SiMe3 ligands, respectively.
Seven proton signals (one of them with double intensity) are
seen in the cyclopentadienyl region indicating magnetically
non-equivalent halves on both substituted cyclopentadienyl
rings. The 19F NMR spectra are not temperature dependent
either, showing the presence of inequivalent C6F5 rings, for
which the platinum co-ordination plane is not a mirror plane
(AFMRX systems, see Experimental section).
C5H4PPh2 group. The centroid(1)–Ti–centroid(2) angle of
133.5Њ as well as the titanium–centroid distances (2.039 and
2.049 Å) are in the usual range found for related complexes
such as [{(Mo(CO)4}2{µ-(PPh2C5H4)2Ti(SPh)2}] (2.065 Å)4e or
[(η5-C5H4SiMe3)2Ti(µ-SPh)2Pd(C6F5)2] [2.07(2), 2.05(1) Å]4b
with the cyclopentadienyl rings exhibiting an antiperiplanar
(staggered) disposition. As was expected the two titanium to
sulfur linkages are very different, the shortest corresponding
t
᎐
to the unco-ordinated SC᎐CBu . The bond between the metal
᎐
to the sulfur of the terminal thioalkyne ligand [Ti–S(2) 2.366(4)
Å] is slightly shorter than that observed in 1a [2.451(4) Å] but
in the range found for other mononuclear titanocene dithio-
lates such as [Ti(η5-C5H5)2(SEt)2] [2.398(3) and 2.387(3) Å].20
The other sulfur atom S(1) is bridging between titanium
and platinum. The Ti–S(1) bond distance [2.532(4) Å] is sub-
stantially longer than the corresponding Pt–S(1) bond length
[2.360(3) Å] and both slightly longer than those previously
observed in the trimetallic complex [(OC)4Mo(µ-PPh2C5H4)2-
Ti(µ-SPh)2Pt(C6F5)2]4c [Ti–S 2.305(1), 2.456(2); Pt–S 2.256(1),
2.347(1) Å]. However, these distances lie in the range of those
for other thiolate-bridged containing titanium or platinum
centres.3,4,21,22 The Pt–P bond distance of 2.277(3) Å (and also
the Pt–S) is comparable with that found in [Pt(SC5H9N-
Me2)(dppe)].22 The S(1)–Ti–S(2) angle of 89.39(12)Њ is slightly
A single crystal X-ray structural determination of complex
8 (Fig. 4) confirmed that the mononuclear precursor acts as
a P,S bidentate ligand towards the “cis-Pt(C6F5)2” fragment.
J. Chem. Soc., Dalton Trans., 1998, 3199–3208
3203

View Article Online
smaller than that seen in 1a [92.30(13)Њ] and those observed
in related mononuclear titanocene bis(thiolate) complexes
[Ti(η5-C5H4SiMe3)2(SC6F5)2] [100.6(1)Њ],14a [Ti(η5-C5H5)2(SR)2]
[R = Ph (99.4Њ),23 or Et (93.8Њ)20] or titanocene thiolate bridged
[(η5-C5H4SiMe3)2Ti(µ-SPh)2Pd(C6F5)2]4b [95.7(2)Њ] complexes.
The internal angles at platinum and at bridging sulfur [P(1)–Pt–
S(1) 83.92(11)Њ acute and Pt–S(1)–Ti 102.51(12)Њ obtuse] are in
accordance with the very long Pt ؒ ؒ ؒ Ti distance [3.817(3) Å]
Syntheses
5
t
᎐
[Ti(ç -C5H4SiMe3)(SC᎐CBu )2] 1a. To a diethyl ether solution
᎐
(20 cm3) of LiBun (1.66 cm3, 2.66 mmol) cooled at Ϫ20 ЊC
t
3
᎐
was added Bu C᎐CH (0.32 cm , 2.66 mmol). After 10 min of
᎐
stirring S8 (0.085 g, 0.33 mmol) was introduced in the Schlenk
and the cooling bath was removed. The mixture was stirred
for 45 min at room temperature and subsequently added
dropwise to another diethyl ether solution (25 cm3) of
[Ti(η5-C5H4SiMe3)2Cl2] (0.50 g, 1.27 mmol) cooled at Ϫ70 ЊC.
The bright green solution obtained was kept under nitrogen
with continuous stirring for 1 h while the temperature slowly
reached Ϫ10 ЊC. The solvent was evaporated to dryness,
the residue then extracted with pentane and filtered through a
pad of Celite. The resulting solution was concentrated and
cooled to Ϫ20 ЊC to yield dark green needles of complex 1a
(0.63 g, 85%) (Found: C, 61.13; H, 8.03. C28H44S2Si2Ti requires
t
᎐
found. The acetylenic fragments, C᎐CBu , are located on the
᎐
same side of the S(1)–Ti(1)–S(2) plane adopting an endo (syn)
᎐
conformation. Their structural data, C᎐C bonds [C(38)–C(39)
᎐
1.19(2), C(44)–C(45) 1.20(2) Å] and bond angles [S(1)–C(38)–
C(39) 175.3(11); C(38)–C(39)–C(40) 178.2(13), S(2)–C(44)–
C(45) 179.3(11), C(44)–C(45)–C(46) 178.2(13)Њ], are in the
usual range and deserve no further comment.
As was mentioned before, complex [Ti(η5-C5H4PPh2)2-
t
᎐
(SC᎐CBu ) ] 3a is very unstable both in the solid state and in
᎐
C, 61.28; H, 8.08%); νmax/cmϪ1 2129 (C᎐C). MS: m/z 548
2
᎐
᎐
solution. In preliminary experiments it was treated with
[Mo(CO)4(nbd)] (1 equivalent) in toluene either at room or
lower (Ϫ40 ЊC) temperature, but unfortunately the reaction
failed, giving just decomposition products and, therefore, no
more experiments were made with this precursor.
5
t
ϩ
5
᎐
{(η -C H SiMe ) Ti(SC᎐CBu ) ] , 8}, 435 {[(η -C H SiMe ) -
᎐
5
4
t
3
2
2
5
4
3 2
ϩ
5
ϩ
1
᎐
(SC᎐CBu )] , 100} and 322 {[(η -C H SiMe ) Ti] , 60%}. H
᎐
5
4
3 2
NMR (CDCl3): δ 6.46 (t, 4 H, C5H4SiMe3), 6.38 (t, 4 H,
C5H4SiMe3), 1.35 (s, 18 H, But) and 0.24 (s, 18 H, SiMe3).
13C-{1H} NMR (CDCl3): δ 123.3 (s, C1 of C5H4), 122.0 (s, C2,5
In summary, bis(alkynethiolate)titanium complexes [Ti(η5-
of C5H4), 119.4 (s, C3,4 of C5H4), 117.5 (s, C᎐C), 80.8 (s, C᎐C),
᎐
᎐
5
᎐
᎐
᎐
C H RЈ)(η -C H RЉ)(SC᎐CR) ] 1–3 have been prepared from
᎐
31.8 (s, But) and 0.17 (s, SiMe3).
5
4
5
4
2
[Ti(η5-C5H4RЈ)(η5-C5H4RЉ)Cl2], by using classical metal–
halogen exchange reactions with LiSC᎐CR reagents. In spite
᎐
᎐
5
᎐
[Ti(ç -C H SiMe ) (SC᎐CPh) ] 1b. This compound was
᎐
5
4
3
2
2
of the presence of two potential bifunctionalities, the lone pair
obtained following the above procedure starting from
᎐
at the sulfur atom and the acetylenic moiety on each SC᎐CR,
᎐
5
᎐
5
t
[Ti(η -C H SiMe ) Cl ] (0.45 g, 0.76 mmol) and LiSC᎐CPh
᎐
5
4
3
2
2
᎐
the mononuclear [Ti(η -C H SiMe ) (SC᎐CR) ] (R = Bu 1a or
᎐
5
4
3
2
2
(1.60 mmol). After 1.5 h of stirring the resulting diethyl
ether solution was concentrated and filtered through a pad
of Celite. Crystallisation from a saturated diethyl ether solution
at Ϫ20 ЊC afforded dark green crystals of compound 1b (85%)
Ph 1b) complexes serve only as bidentate (S,S) metalloligands
when treated with d6 [Mo(CO)4(nbd)] or d8 cis-[M(C6F5)2(thf)2]
(M = Pt or Pd) substrates. The co-ordination of the acetylenic
fragments cannot be forced even in presence of an excess of
these latter reagents, reactions which lead to the same doubly
thiolate-bridged early–late heterodimetallic products 4–6 (see
Experimental section). The NMR data reveal that in all cases
the products are isolated as a syn:anti mixture of isomers with
a clear thermodynamic preference for the syn conformation
in the palladium mixed-metal complexes (≈1:1 for Ti–Mo 4a
and Ti–Pt 5 vs. 5:1 6a, 10:1 6b). The variable NMR data
confirm that both isomers interconvert on the NMR timescale
at the highest accessible temperature (ϩ50 ЊC) (4a and 6 fast
5 slow).
(Found: C, 65.03; H, 6.09. C32H36S2Si2Ti requires C, 65.28; H,
6.16%); νmax/cmϪ1 2134 (C᎐C). MS: m/z 588 {[(η -C H SiMe ) -
5
᎐
᎐
5
4
3 2
ϩ
ϩ
᎐
᎐
Ti(SC᎐CPh) ] , 4}, 455 {[(Ti(SC᎐CPh)] , 100} and 322
᎐
᎐
2
{[(η5-C5H4SiMe3)2Ti]ϩ, 95%}. H NMR (CDCl3): δ 7.41–7.37
(m, 4 H, Ph), 7.23–7.19 (m, 6 H, Ph), 6.62 (t, 4 H, C5H4SiMe3),
6.53 (t, 4 H, C5H4SiMe3) and 0.28 (s, 18 H, SiMe3). 13C-{1H}
NMR (CDCl3): δ 138.8–126.9 (s, C6H5), 124.3 (s, C1 of C5H4),
1
122.2 (s, C2,5 of C5H4) 119.7 (s, C3,4 of C H ), 107.3 (s, C᎐C),
᎐
᎐
5
4
᎐
93.0 (s, C᎐C) and 0.16 (s, SiMe ).
᎐
3
5
5
t
᎐
[Ti(ç -C H SiMe )(ç -C H PPh )(SC᎐CBu ) ]
2a.
This
᎐
Similar to previous observations, a favoured co-ordination
through phosphine ligands with these late transition metals
is evidenced by the fact that the mixed ligand complex
5
4
3
5
4
2
2
compound was obtained following the same procedure as
for 1a but the final residue was extracted with heptane
(73% yield). The precursors used were [Ti(η5-C5H4SiMe3)-
5
5
t
᎐
[Ti(η -C H SiMe )(η -C H PPh )(SC᎐CBu ) ] 2a acts as biden-
᎐
5
4
3
5
4
2
2
5
t
᎐
(η -C H PPh )Cl ] (0.37 g, 0.56 mmol) and LiSC᎐CBu (1.17
᎐
tate P,S when treated with cis-[M(C6F5)2(thf)2] (M = Pt or Pd)
yielding 8 and 9, respectively and, as a tridentate organo-
metallic metallo ligand toward [Mo(CO)4(nbd)] or [Mo(CO)3-
(NCMe)3], giving [(η5-C5H4SiMe3)Ti(µ-η5 :κ-P-C5H4PPh2)-
5
4
2
2
mmol) (Found: C, 66.82; H, 6.90. C37H45PS2SiTi requires
C, 67.25; H, 6.86%); νmax/cmϪ1 2145 (C᎐C). MS: m/z 660
᎐
᎐
5
5
t
ϩ
5
᎐
{[(η -C H SiMe )(η -C H PPh )Ti(SC᎐CBu ) ] , 30}, 547 {[(η -
᎐
5
4
3
5
4
2
2
5
t
ϩ
t
᎐
C H SiMe )(η -C H PPh )Ti(SC᎐CBu )] , 100} and 432
᎐
᎐
(µ-SC᎐CBu ) Mo(CO) ] 7.
5
4
3
5
4
2
᎐
2
3
{[(η5-C5H4SiMe3)(η5-C5H4PPh2)Ti]ϩ, 50%}. 1H NMR (CDCl3):
δ 7.41–7.37 (m, 4 H, Ph), 7.23–7.19 (m, 6 H, Ph), 6.54 (m,
2 H, C5H4PPh2), 6.38 (t, 2 H, C5H4SiMe3), 6.34 (t, 2 H,
C5H4SiMe3), 6.11 (m, 2 H, C5H4PPh2), 1.31 (s, 18 H, But)
and 0.17 (s, 9 H, SiMe3). 31P-{1H} NMR: δ Ϫ15.2 (s, C5H4-
PPh2). 13C-{1H} NMR (CDCl3): δ 133.8–128.5 (s, C6H5), 124.5,
Experimental
Reactions were carried out under an atmosphere of argon
by means of conventional Schlenk techniques.24 Solvents
were purified according to standard procedures.25 The
complexes [Ti(η5-C5H4SiMe3)2Cl2],26 [Ti(η5-C5H4SiMe3)(η5-
C5H4PPh2)Cl2],14b [Ti(η5-C5H4PPh2)2Cl2],27 [Mo(CO)4(nbd)],28
[Mo(CO)3(NCMe)3]29 and cis-[M(C6F5)2(thf)2]30 (M = Pt or
Pd) were prepared as previously published. All other reagents
were used as obtained commercially. Microanalyses were
determined with Perkin-Elmer 2400 and 240-B microanalysers.
Infrared spectra (KBr) were recorded on Perkin-Elmer 1600 FT
and FT-IR 1000 spectrophotometers, NMR spectra on Bruker
AMX-300 or ARX-300 with chemical shifts reported in ppm
relative to external standards (SiMe4 for 1H and 13C, CFCl3 for
19F and H3PO4 for 31P) and mass spectra (FABϩ) on a VG
Autospec spectrometer.
123.5, 123.4, 121.8, 121.5, 120.3, 120.1, 120.0, 119.9, 119.1
t
᎐
᎐
(s, C H ), 117.8 (s, C᎐C), 80.2 (s, C᎐C), 31.7 (s, Bu ) and 0.11 s,
᎐
᎐
5
4
SiMe3).
5
t
᎐
[Ti(ç -C H PPh ) (SC᎐CBu ) ] 3a. The synthesis was
᎐
5
4
2
2
2
performed as described for complex 1a starting from
5
t
᎐
[Ti(η -C H PPh ) Cl ] (0.45 g, 0.73 mmol) and LiSC᎐CBu
᎐
5
4
2
2
2
(1.53 mmol). After 30 min of stirring the resulting diethyl
ether solution was concentrated and filtered through a pad of
Celite. The solvent was evaporated to dryness affording 3a as
a green solid (70%). νmax/cmϪ1 2129 (C᎐C). H NMR (CDCl ):
1
᎐
᎐
3
δ 7.27–7.17 (m, 10 H, Ph), 6.40 (t, 4 H, C5H4PPh2), 6.01 (m, 4
3204
J. Chem. Soc., Dalton Trans., 1998, 3199–3208

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H, C5H4PPh2) and 1.33 (s, 18 H, But). 31P-{1H} NMR: δ Ϫ15.5
(s, C5H4PPh2). The 13C NMR spectrum could not be recorded
due to the low stability in solution.
(≈355)], Ϫ118.6 [dm (≈465)], Ϫ119.4 [dm (392)] (Fo syn and anti
isomers), Ϫ161.3 (t, Fp, anti isomer), Ϫ161.5 (t, Fp, syn isomer),
Ϫ164.2 (m, Fm, syn and anti isomers) (syn:anti 0.9:1); at 20 ЊC,
Ϫ117.6 [dm, overlapping of two Fo (≈411, ≈337)], Ϫ118.6 [dm
(≈455)], Ϫ119.3 [dm (≈385 Hz)] (ratio 2:1:1, Fo, syn and anti),
Ϫ162.0m, Ϫ162.25m (ratio 0.9:1, Fp, syn and anti), Ϫ164.5,
Ϫ165.0 (m, ratio 2:2, Fm, syn and anti); at ϩ50 ЊC, Ϫ117.5 [br
(358)], Ϫ118.6 [d, br (446)], Ϫ119.2 [d, br (391)] (ratio 2:1:1,
Fo, syn and anti), Ϫ162.3 (m, br, overlapping of two Fp, syn and
anti), Ϫ164.6 (m, br), Ϫ165.3m, (ratio 1:1, Fm, syn and anti).
13C-{1H} NMR (CDCl3): at Ϫ50 ЊC, δ 148.05, 144.96, 138.5,
5
t
᎐
[(ç -C H SiMe ) Ti(ì-SC᎐CBu ) Mo(CO) ] 4a (syn and anti).
᎐
5
4
3
2
2
4
5
t
᎐
To a solution of [Ti(η -C H SiMe ) (SC᎐CBu ) ] 1a (0.20 g, 0.36
᎐
5
4
3
2
2
mmol) in toluene (25 cm3) was added [Mo(CO)4(nbd)] (0.32 g,
1.08 mmol) and the mixture stirred at room temperature for
30 h. The solvent was removed in vacuo and the solid obtained
purified by chromatography on silica gel 100. Elution with
hexane–toluene (3:1) afforded a green-blue band of complex
4a (0.16 g, 60%) (syn:anti ratio ≈1:1). Identical results were
obtained starting from 1a and 1 equivalent of [Mo(CO)4(nbd)],
but in that case longer periods of stirring (≈72 h) were necessary
(Found: C, 50.51; H, 5.73. C32H44MoO4S2Si2Ti requires C,
135.3, 123.3, 116.05 (br, C6F5), 130.1, 122.1, 120.8, 120.2, 120.0,
᎐
119.6, 113.1, 112.5, 109.6, 107.0 (s, C H and C᎐C), 67.98s,
᎐
5
4
᎐
67.78s (C᎐C, syn and anti isomers), 30.3 [s, C(CH ) ], 29.1 (s,
᎐
3
3
CMe3), 28.9 (s, CMe3), 0.0 (s, syn isomer), Ϫ0.14 (s, anti isomer)
and Ϫ0.39 (s, syn isomer) [Si(CH3)3].
50.79; H, 5.86%). νmax/cmϪ1 2072 (C᎐C); (toluene solution)
᎐
᎐
2019s, 1929s, 1915vs (CO). MS: m/z 756 {[(η5-C5H4SiMe3)2Ti-
t
ϩ
5
5
᎐
᎐
᎐
(µ-SC᎐CBu ) Mo(CO) ] , <5}, 728 {[(η -C H SiMe ) Ti(µ-SC᎐
[(ç -C H SiMe ) Ti(ì-SC᎐CPh) Pt(C F ) ] 5b (syn and anti).
᎐
᎐
᎐
2
4
5
4
3
2
5
4
3
2
2
6
5 2
CBut)2Mo(CO)3]ϩ, <5%}, 700 {[(η -C H SiMe ) Ti(µ-SC᎐
CBu ) Mo(CO) ] , <5}, 672 {[(η -C H SiMe ) Ti(µ-SC᎐CBu ) -
Mo(CO)] , <5}, 644 {[(η -C H SiMe ) Ti(µ-SC᎐CBu ) Mo] ,
15}, 435 {[(η -C H SiMe ) Ti(SC᎐CBu )] , 50} and 322 {[(η -
A solid mixture of [Ti(η -C H SiMe ) (SC᎐CPh) ] (0.131 g,
5
5
᎐
᎐
᎐
᎐
5
4
3
2
5 4 3 2 2
t
ϩ
5
t
᎐
0.223 mmol) and cis-[Pt(C6F5)2(thf)2] (0.150 g, 0.223 mmol)
was treated with toluene (5 cm3). Immediately the resulting
brown-red solution was concentrated in vacuo, giving an
᎐
2
2
5
4
3
2
2
ϩ
ϩ
5
t
᎐
᎐
5
4
3
2
2
5
t
ϩ
5
᎐
᎐
5
4
3 2
C5H4SiMe3)2Ti]ϩ, 100%}. 1H NMR (CDCl3): at Ϫ50 ЊC, δ 6.30
(2 H), 6.22 (2 H, 6.12, 5.84, 5.67 (1 H each), 5.52 (2 H), 5.26
(4 H), 5.12, 4.88, 4.79 (1 H each) (C5H4 syn, anti isomers), 1.20s,
1.17s (But), 0.37 (s, SiMe3, anti isomer), 0.42s, 0.22s (SiMe3,
syn isomer); at 20 ЊC, 6.31 (s, br, 2 H, C5H4, syn isomer), 6.21
(s, br, 2 H, C5H4, syn isomer), 5.55 (s, br, 6 H, C5H4, anti and
syn isomers), 5.36 (s, br, 2 H, C5H4, syn isomer), 5.27 (s, br, 4 H,
C5H4, anti isomer), 1.23 (s, But), 1.20 (s, But), 0.39 (s, 18 H,
SiMe3, anti isomer), 0.44, 0.33 (s, SiMe3, syn isomer), (ratio
syn:anti ≈1:1); at ϩ50 ЊC, cyclopentadienyl region very broad
(≈6.2, 5.4 br), 1.24 (s, But), 0.41 (s, br, SiMe3). 13C-{1H} NMR
(CDCl3): δ 217.9 (s, CO equatorial, syn isomer), 217.2 (s, CO
equatorial, anti isomer), 204.7 (s, CO axial, syn isomer), 203.1
(s, CO axial, anti isomer), 201.7 (s, CO axial, syn isomer),
129.3br, 123.4br, 116.8, 114.5, 113.3, 112.4, 106.2, 102.2, 101.2
orange-red residue, identified as [(η5-C5H4SiMe3)2Ti(µ-
᎐
SC᎐CPh) Pt(C F ) ] 5b (0.174 g, 70% yield) (syn:anti ratio at
᎐
2
6
5 2
Ϫ50 ЊC, 1:1). When the reaction in a molar ratio 1:2 {0.010 g,
0.0170 mmol of complex 1b and 0.023 g, 0.034 mmol of cis-
[Pt(C6F5)2(thf)2] in 0.6 cm3 of CDCl3} was monitored by NMR
spectroscopy at 20 ЊC considerable decomposition took place,
with 5b being the major product. After longer periods (≈3 h)
more decomposition was observed (Found: C, 47.47; H, 3.38;
S, 5.31. C44F10H36PtS2Si2Ti requires C, 47.27; H, 3.24; S,
5.73%). νmax/cmϪ1 2165m (C᎐C), 801vs, (br) (C F )X–sens. MS:
᎐
᎐
6
5
m/z 1117 (Mϩ, 10), 619 {[(η -C H SiMe ) Ti(SC᎐CPh)-
5
᎐
᎐
5
4
3 2
ϩ
5
ϩ
᎐
(C F ) Ϫ 3H] ,14},457{[(η -C H SiMe ) Ti(SC᎐CPh) ϩ 2H] ,
᎐
6
5
5
4
3 2
56} and 322 {[(η5-C5H4SiMe3)2Ti]ϩ, 100%}. 1H NMR (CDCl3):
at Ϫ50 ЊC, δ 7.37–7.20 (Ph), 6.59, 6.46, 6.41, 6.37, 6.12, 6.09,
6.03, 5.91 (s, identical ratio, C5H4, syn and anti isomers), 0.43 (s,
SiMe3, syn isomer), 0.36 (s, SiMe3, anti isomer), 0.28 (s, SiMe3,
syn isomer) (syn:anti ≈1:1); at 20 ЊC, 7.37–7.16 (Ph), 6.61, 6.48,
6.41, 6.17, 6.12, 6.10, 5.95 (s, ratio 1:1:2:1:1:1:1, C5H4, syn
and anti isomers), 0.43 (s, SiMe3, syn isomer), 0.38 (s, SiMe3,
anti isomer), 0.30 (s, SiMe3, syn isomer) (syn:anti ≈1:1);
at ϩ50 ЊC, 7.36–7.15 (Ph), 6.60sh, 6.45br, 6.14br, 6.01sh (C5H4)
and 0.39 (s, br, SiMe3). 19F NMR [CDCl3, 3J(Pt–Fo)/Hz in
parentheses]: at Ϫ50 ЊC, δ Ϫ117.8 [d (430), 2F], Ϫ118.5 [d (451),
2F], Ϫ118.97 [d (365), 2F] Ϫ120.0 [d (398), 2F] (Fo, syn and anti
isomer), Ϫ160.6, Ϫ161.5 (t, Fp, syn and anti isomer), Ϫ163.3,
Ϫ164.0 (m, Fm, syn and anti isomer) (syn:anti 1:1); at 20 ЊC,
Ϫ117.6 [d (408), 2F], Ϫ118.6 [dm, overlapping of two Fo (≈458,
≈389), 4F], Ϫ119.8 [d (392), 2F], (Fo, syn and anti isomer),
Ϫ161.3, Ϫ161.7 (t, Fp, syn and anti isomer), Ϫ163.8, Ϫ164.6
(m, Fm, syn and anti isomer) (syn:anti ≈1:1); at ϩ50 ЊC, Ϫ117.5,
Ϫ118.3, Ϫ118.5, Ϫ118.98 (br, Fo), Ϫ161.6, Ϫ161.9 (br, Fp),
Ϫ164.0, Ϫ164.9 (br, Fm) (syn and anti isomer). 13C-{1H} NMR
(CDCl3): at Ϫ50 ЊC, δ 148.2, 145.2, 138.7, 138.2, 135.4–134.0,
116.6, 113.8 (br, C6F5), 138.2, 131.3–112.5 (s, C6H5, C5H4),
᎐
᎐
(s, C H , C᎐C), 75.9 (s, C᎐C), 31.1 [s, C(CH ) ], 28.9 (s, CMe )
᎐
᎐
5
4
3
3
3
and 0.14 (s, SiMe3).
5
t
᎐
[(ç -C H SiMe ) Ti(ì-SC᎐CBu ) Pt(C F ) ] 5a (syn and anti).
᎐
5
4
3
2
2
6
5 2
5
t
᎐
A deep green solution of [Ti(η -C H SiMe ) (SC᎐CBu ) ]
᎐
5
4
3
2
2
(0.098 g, 0.178 mmol) in CH2Cl2 (10 cm3) was treated with
cis-[Pt(C6F5)2(thf)2] (0.120 g, 0.178 mmol) and, immediately,
turned red-brown. The mixture was stirred for 5 min and then
the solvent was removed in vacuo. Addition of n-heptane
(≈5 cm3) to the residue afforded an orange-brown solid (0.153 g,
80% yield) identified as a mixture of syn and anti isomers
5
t
᎐
of [(η -C H SiMe ) Ti(µ-SC᎐CBu ) Pt(C F ) ] 5a. When the
᎐
5
4
3
2
2
6
5 2
reaction was carried out in a molar ratio 1:2 using complex 1a
(0.010 g, 0.019 mmol) and cis-[Pt(C6F5)2(thf)2] (0.025 g, 0.037
mmol) in CDCl3 (0.6 cm3) and monitored by 1H and 19F NMR
spectroscopy at 20 ЊC the complex 5a was observed (major
component) in addition to decomposition products (Found:
C, 44.50; H, 3.70; S, 5.95. C40F10H44PtS2Si2Ti requires C,
44.57; H, 4.11; S, 5.48%). νmax/cmϪ1 2168m (C᎐C), 800vs,
᎐
᎐
ϩ
t ϩ
᎐
᎐
᎐
(br) (C6F5)X–sens. MS: m/z 1077 (M , 28), 964 ([M Ϫ SC᎐CBu ] ,
99.3s, 96.4s (C᎐C syn and anti isomers), 79.7s, 79.5s (C᎐C
᎐
᎐
᎐
32), 940 ([M Ϫ C5H4SiMe3]ϩ, 25), 910 ([M Ϫ C6F5]ϩ, 94),
syn and anti isomers), Ϫ0.0 (s, syn and anti isomer) and Ϫ0.35
(s, syn isomer) [Si(CH3)3].
5
t
ϩ
5
᎐
631 {[(η -C H SiMe ) Ti(SC᎐CBu )Pt] , 58}, 475 {[(η -C H -
᎐
5
4
3
2
5
4
t
ϩ
5
᎐
SiMe )(C H )Ti(SC᎐CBu ) ] , 100}, 435 {[(η -C H SiMe ) -
᎐
3
5
4
t
2
5
4
3 2
ϩ
5
ϩ
5
t
᎐
᎐
᎐
Ti(SC᎐CBu )] , 70} and 322 {[(η -C H SiMe ) Ti] , 100%}.
[(ç -C H SiMe ) Ti(ì-SC᎐CBu ) Pd(C F ) ] 6a (syn and anti).
᎐
5
4
3
2
5 4 3 2 2 6 5 2
1H NMR (CDCl3): at 20 ЊC, δ 6.46, 6.29, 6.23, 6.13, 5.94, 5.87,
5.73 (s, ratio 1:1:1:1:2:1:1, C5H4, syn and anti isomers), 1.21
(s, But), 1.14 (s, But), 0.39 (s, SiMe3, syn isomer), 0.33 (s, SiMe3,
anti isomer), 0.25 (s, SiMe3, syn isomer), (syn:anti 0.9:1);
approximately the same spectra is observed at Ϫ50 ЊC; at
ϩ50 ЊC, the signals are broad, 6.5, 6.3, 6.2, 5.98, 5.90, 5.80 (br,
C5H4), 1.21, 1.17 (br, But), 0.35 (br, SiMe3 anti and syn isomers),
This product was prepared in a similar way to complex 5b
by using the appropriate starting precursors, [Ti(η5-C5H4-
t
᎐
SiMe ) (SC᎐CBu ) ] (0.141 g, 0.256 mmol) and cis-
᎐
3
2
2
[Pd(C6F5)2(thf)2] (0.150 g, 0.256 mmol). It was isolated by
removing the solvent in vacuo, (yield 0.16 g 63%) (mixture of
syn and anti isomers, ratio ≈5:1 at Ϫ50 ЊC). When an excess of
cis-[Pd(C6F5)2(thf)2] was employed {1:2 molar ratio; 0.012 g,
0.021 mmol of 1a and 0.025 g, 0.043 mmol of cis-
[Pd(C6F5)2(thf)2] in 0.6 cm3 of CDCl3} a mixture of 6a and
3
0.28 (SiMe3, syn isomer). 19F NMR [CDCl3, J(Pt–Fo)/Hz in
parentheses]: at Ϫ50 ЊC, δ 117.94 [dm (417)], Ϫ118.07 [dm
J. Chem. Soc., Dalton Trans., 1998, 3199–3208
3205

View Article Online
cis-[Pd(C6F5)2(thf)2] was observed by NMR spectroscopy
[s, Si(CH3)3, anti isomer], Ϫ0.17 (s) and Ϫ0.39 (s) [Si(CH3)3,
syn isomer].
(Found: C, 48.08; H, 4.21; S, 6.32. C40F10H44PdS2Si2Ti requires
C, 48.56; H, 4.48; S, 6.48%). νmax/cmϪ1 2166m (C᎐C), 786s, 778s
᎐
᎐
(C6F5)X–sens. MS: m/z 1011 ([M ϩ Na]ϩ, 2), 541 {[(η5-C5H4-
[(ç -C H SiMe )Ti(ì-ç :ê-P-C H PPh (ì-SC᎐CBu ) -
5
5
t
᎐
᎐
5
4
3
5
4
2
2
t
ϩ
SiMe ) Ti(SC᎐CBu )Pd] , 7}, 492 {[(η5-C5H4SiMe3)2Pd-
Mo(CO)3] 7. To a toluene solution (25 cm3) of [Ti(η5-C5H4-
᎐
᎐
3
2
t
ϩ
5
t
ϩ
5
t
᎐
᎐
᎐
᎐
(SC᎐CBu ) Ϫ H] , 7}, 435 {[(η -C H SiMe ) Ti(SC᎐CBu )] ,
SiMe )(η -C H PPh )(SC᎐CBu ) ] 2a (0.20 g, 0.30 mmol) was
᎐
᎐
5
4
3
2
3 5 4 2 2
53} and 322 {[(η5-C5H4SiMe3)2Ti]ϩ, 100%}. 1H NMR (CDCl3):
at Ϫ50 ЊC, δ 6.45, 6.39, 6.07, 6.00 (s, C5H4, syn isomer), 6.31,
5.72 (C5H4, anti isomer), 1.23 (s, But, syn isomer), 1.14 (s, But,
anti isomer), 0.37 (s, SiMe3, syn isomer), 0.27 (s, SiMe3, anti
isomer), 0.19 (s, SiMe3, syn isomer) (syn:anti 5:1); at 20 ЊC,
6.48, 6.43, 6.11, 6.07 (s, ratio 1:1:1:1, C5H4, syn isomer), 6.30,
5.81 (br, C5H4, anti isomer), 1.26 (s, But, syn isomer), 1.22 (sh,
But, anti isomer), 0.37 (s, SiMe3, syn isomer), 0.30 (s, SiMe3, anti
isomer) and 0.23 (s, SiMe3, syn isomer); at ϩ50 ЊC, 6.42, 6.11
(br, C5H4), 1.25, (s, But) and 0.31 (s, SiMe3). 19F NMR (CDCl3):
at Ϫ50 ЊC, δ Ϫ115.2 (d, anti isomer), Ϫ115.5 (d, syn isomer),
Ϫ115.9 (dm, syn isomer), Ϫ117.0 (d, anti) (Fo, ratio syn:anti
5:1), Ϫ160.7 (t, overlapping of two Fp, syn and anti isomer),
Ϫ163.1, Ϫ163.8 (br, Fm, syn and anti isomer); at 20 ЊC, Ϫ114.9
(d, anti isomer), Ϫ115.5 (m, overlapping of two Fo, syn isomer)
Ϫ116.8 (d, anti isomer) (Fo, syn:anti 3:1), Ϫ161.4 (t, Fp),
Ϫ163.8, Ϫ164.5 (m, Fm, syn and anti isomer); at ϩ50 ЊC,
Ϫ115.3 (br, Fo), Ϫ161.7 (t, Fp), Ϫ164.1, Ϫ164.7 (br, Fm). 13C-
added [Mo(CO)3(NCMe)3] (0.11 g, 0.36 mmol). After 3 h of
stirring at room temperature the solvent was evaporated to
dryness and the solid residue chromatographed on silica gel
100. A violet band was eluted by hexane–toluene (1:1) and its
recrystallisation from heptane at Ϫ20 ЊC yielded 7 as a dark
violet solid (0.13 g, 53%). Complex 7 can also be obtained
in very low yield (12%) using 2a (0.23 g, 0.34 mmol) and
[Mo(CO)4(nbd)] (0.12 g, 0.42 mmol) as precursors (Found:
C, 56.51; H, 5.25. C40H45MoO3PS2SiTi requires C, 57.14; H,
5.39%). νmax/cmϪ1 2070 (C᎐C); (toluene solution) 1956vs,
᎐
᎐
1895m, 1879s (CO). MS: m/z 840 {[(η5-C5H4SiMe3)(η5-C5H4-
t
ϩ
5
᎐
PPh )Ti(µ-SC᎐CBu ) Mo(CO) ] , <5}, 784 {[(η -C H SiMe )-
᎐
2
2
3
5
4
3
5
t
ϩ
5
᎐
(η -C H PPh )Ti(µ-SC᎐CBu ) Mo(CO)] , <5}, 756 {[(η -C H -
᎐
5
4
2
2
5
4
5
5
t
ϩ
᎐
SiMe )(η -C H PPh )Ti(µ-SC᎐CBu ) Mo] , 100}, 547 {[(η -
᎐
3
5
4
2
2
5
t
ϩ
5
᎐
C H SiMe )(η -C H PPh )Ti(µ-SC᎐CBu )] , 15} and 434 {[(η -
᎐
5
4
3
5
4
2
C5H4SiMe3)(η5-C5H4PPh2)Ti]ϩ, 65%}. 1H NMR (CDCl3):
δ 7.61–7.52 (m, 4 H, Ph), 7.33–7.28 (m, 6 H, Ph), 6.23 (s, br, 2 H,
C5H4PPh2), 5.61 (s, br, 2 H, C5H4SiMe3), 5.49 (s, br, 2 H,
C5H4SiMe3), 5.17 (s, br, 2 H, C5H4PPh2), 1.20 (s, 18 H, But) and
0.41 (s, 9 H, SiMe3); similar spectra were obtained at low
(Ϫ50 ЊC) and high (ϩ50 ЊC) temperature. 31P-{1H} NMR: δ
{1H} NMR (CDCl3): at Ϫ50 ЊC, δ 147.7, 144.7, 138.5–137.1,
᎐
135.3–133.8, 120.4 (br, C F ), 129.4–110.0 (s, C H , C᎐C),
᎐
6
5
5
4
᎐
᎐
70.0 (s, C᎐C, anti isomer), 69.8 (s, C᎐C, syn isomer), 30.4
᎐
᎐
[s, C(CH3)3, syn isomer], 29.3 [s, C(CH3)3, anti isomer], 29.1 (s,
CMe3, syn isomer), 27.6 (s, CMe3, anti isomer), Ϫ0.17 [s,
Si(CH3)3, syn isomer], Ϫ0.27 [s, Si(CH3)3, anti isomer] and
Ϫ0.52 [s, Si(CH3)3, syn isomer].
39.7 (s, C5H4PPh2). 13C-{1H} NMR (CDCl3): δ 213.8 (s, CO),
᎐
133.3–128.4 (s, C H ), 124.3–100.7 (s, C H ), 111.4 (s, C᎐C),
75.4 (s, C᎐C), 31.1 [s, C(CH ) ], 28.9 [C(CH ) ] and 0.30 (s,
᎐
6
5
5
4
᎐
᎐
3
3
3 3
SiMe3).
5
5
t
5
᎐
᎐
᎐
᎐
[(ç -C H SiMe ) Ti(ì-SC᎐CPh) Pd(C F ) ] 6b (syn and anti).
[(ç -C H SiMe )(SC᎐CBu )Ti(ì-ç :ê-P-C H PPh )(ì-SC᎐
᎐
᎐
5
4
3
2
2
6
5
2
5
4
3
5
4
2
The reaction was performed as described for complex 5a in
CBut)Pt(C6F5)2] 8. To a toluene solution (20 cm3) of com-
plex 2a (0.120 g, 0.18 mmol) at Ϫ20 ЊC was added cis-
[Pt(C6F5)2(thf)2] (0.122 g, 0.18 mmol). The cooling bath was
then removed and the mixture stirred for 15 min. The resulting
violet solution was subsequently filtered through a pad of
Celite and concentrated (ca. 10 cm3). Addition of n-hexane (10
cm3) afforded complex 8 as a violet crystalline solid (0.150,
70%) (Found: C, 49.85; H, 3.85. C49H45F10PPtS2SiTi requires C,
3
5
᎐
toluene (5 cm ) starting from [Ti(η -C H SiMe ) (SC᎐CPh) ]
᎐
5
4
3
2
2
(0.150 g, 0.255 mmol) and cis-[Pd(C6F5)2(thf)2] (0.149 g, 0.255
mmol). In this case 6b was precipitated as a red-garnet solid by
adding n-hexane (3 cm3) (0.23 g, 88% yield) (syn:anti at Ϫ50 ЊC,
10:1). When the reaction was carried out in a 1:2 molar ratio
in 0.6 cm3 of CDCl3{0.013 g, 0.021 mmol of 1b and 0.025 g,
0.043 mmol of cis-[Pd(C6F5)2(thf)2]} a mixture of 6b and
cis-[Pd(C6F5)2(thf)2] was observed by NMR spectroscopy
(Found: C, 50.79; H, 3.61; S, 5.91. C44F10H36PdS2Si2Ti requires
49.46; H, 3.81%). νmax/cmϪ1 2157w, 2141m (C᎐C), 800vs, 786vs
᎐
᎐
(C6F5)X–sens. MS: m/z 1077 {[(η5-C5H4SiMe3)(η5-C5H4PPh2)-
C, 51.34; H, 3.52; S, 6.23%). νmax/cmϪ1 2165m (C᎐C), 789vs,
Ti(SC᎐CBu )Pt(C F ) ] , 22}, 661 {[(η -C H SiMe )(η -C H -
t
ϩ
5
5
᎐
᎐
᎐
᎐
6
t
5
ϩ
2
5
4
3
5
4
5
778vs (C6F5)X–sens. MS: m/z 861 {[(η -C H SiMe ) Ti(SC᎐CPh) -
{[(η -C H SiMe ) Ti(SC᎐CPh)-
(C F ) Ϫ 3H] ,14},457{[(η -C H SiMe ) Ti(SC᎐CPh) ϩ 2H] ,
PPh )Ti(SC᎐CBu ) ] , 55}, 548 {[(η5-C5H4SiMe3)(η5-C5H4-
2 2
t ϩ 5 5
᎐
᎐
᎐
᎐
᎐
5
4
3
2
2
5
Pd(C6F5)]ϩ,
15},
619
PPh )Ti(SC᎐CBu )] , 100} and 434 {[(η -C H SiMe )(η -C H -
2 5 4 3 5 4
1
᎐
᎐
᎐
5
4
3
2
ϩ
5
ϩ
PPh2)Ti]ϩ, 50%}. H NMR (CDCl3): at Ϫ50 ЊC, δ 7.63 (m),
7.39–7.18 (m) (Ph), 7.01 (s, 2 H), 6.78, 6.68, 6.48, 6.16, 6.08,
5.90 (s, 1 H each) (C5H4), 1.20 (s, 9 H, But), 1.11 (s, 9 H, But)
and 0.13 (s, 9 H, SiMe3); a similar pattern was observed at 20 ЊC
with some of the C5H4 signals slightly displaced. 19F NMR
᎐
᎐
6
5
5
4
3 2
15} and 322 {[(η5-C5H4SiMe3)2Ti]ϩ, 100%}. 1H NMR (CDCl3):
at Ϫ50 ЊC, δ 7.29 (m), 7.17 (m) (Ph), 6.81, 6.57, 6.36, 6.28
(br, C5H4, syn isomer), 6.77, 6.45, 6.21 and 5.92 (C5H4, anti
isomer), 0.38 (s, SiMe3, syn isomer), 0.31 (s, SiMe3, anti isomer),
0.22 (s, SiMe3, syn isomer) (syn:anti, 10:1); at 20 ЊC, 7.27
(m, Ph), 6.83, 6.59, 6.42, 6.31 (br, C5H4), 0.39 (s, SiMe3), 0.26
(s, SiMe3) (syn and anti isomer); at ϩ50 ЊC, 7.33 (d), 7.23
(m) (Ph), 6.66 (vbr), 6.39 (vbr) (C5H4) and 0.34 (s, SiMe3).
19F NMR (CDCl3): at Ϫ50 ЊC, δ Ϫ115.8 (d, anti isomer),
Ϫ115.4 (d, syn isomer), Ϫ116.7 (d, syn isomer), Ϫ117.6 (d, anti
isomer) (Fo, syn:anti 10:1), Ϫ160.1 (t, Fp, anti isomer), Ϫ160.4
(t, Fp, syn isomer), Ϫ162.2, Ϫ163.5 (m, Fm, syn and anti
isomer); at 20 ЊC, Ϫ114.8 (br, anti isomer), Ϫ115.5 (d, syn
isomer), Ϫ116.1 (br, syn isomer), Ϫ117.4 (br, anti isomer)
(Fo, syn:anti ≈7:1), Ϫ161.0 (t, Fp, syn and anti isomer), Ϫ162.9
(br), Ϫ164.2 (m, br) (Fm, syn and anti isomer); at ϩ50 ЊC,
Ϫ115.9 (br, Fo), Ϫ161.2 (t, Fp), Ϫ162.3 (br) and Ϫ163.6 (br,
Fm). 13C-{1H} NMR (CDCl3): at Ϫ50 ЊC, δ 148.4, 147.6, 138.7,
138.1–137.2, 135.5, 134.9–133.8, 121.09, 118.2 (br, C6F5),
3
[CDCl3, J(Pt–Fo)/Hz in parentheses]: at 20 ЊC, δ Ϫ116.6 [m
(343), 1F], Ϫ117.7 [dm (455), 1F], Ϫ118.7 [d (414), 1F], Ϫ120.0
[m, br (326), 1F] (Fo), Ϫ162.7, Ϫ163.4 (t, Fp), Ϫ164.2 (m, 1F),
Ϫ164.5 (m, 1F), Ϫ164.9 (m, 2F) (Fm); a similar pattern was
observed at Ϫ50 ЊC. 31P-{1H} NMR (CDCl3): δ 5.14 [s, C5H4-
PPh2, 1J(Pt–P) = 2361 Hz].
5
t
5
᎐
᎐
᎐
[(ç -C H SiMe )(SC᎐CBu )Ti(ì-ç :ê-P-C H PPh (ì-SC᎐
᎐
5
4
3
5
4
2
CBut)Pd(C6F5)2] 9. The synthesis was performed as de-
scribed for complex 8 starting from 2a (0.15 g, 0.22 mmol)
and cis-[Pd(C6F5)2(thf)2] (0.13 g, 0.22 mmol) (45%) (Found:
C, 53.89; H, 4.19. C49H45F10PPdS2SiTi requires C, 53.44;
H, 4.12%). νmax/cmϪ1 2158w, 2141m (C᎐C), 786vs, 776vs
᎐
᎐
(C6F5)X–sens. MS: m/z 540 {[(η5-C5H4SiMe3)(η5-C5H4PPh2)Ti-
t
ϩ
5
5
᎐
(SC᎐CBu )Pd Ϫ H] , 42} and 434 {[(η -C H SiMe )(η -C H -
᎐
5
4
3
5
4
131.16, (s, Co, C6H5), 128.7, 128.4, 128.2 (s, Cm, C6H5), 125.2,
PPh2)Ti]ϩ, 52%}. 1H NMR (CDCl3): at Ϫ50 ЊC, δ 7.52–7.18 (m,
Ph), 7.03, 7.00, 6.89, 6.71, 6.39 (s, 1 H each), 6.00 (s, 2 H), 5.86
(s, 1 H) C5H4), 1.22 (s, 9 H, But), 1.11 (s, 9 H, But) and 0.13 (s, 9
H, SiMe3); a similar pattern was observed at 20 ЊC. 19F NMR
᎐
123.4, 123.1, 122.6 (s, C H , C H , syn), 103.5 (s, C᎐C syn
᎐
6
5
5
4
᎐
isomer), 81.6 (s, C᎐C syn isomer), small signals seen at 121.1
and 99.2 (C᎐C) tentatively attributed to the anti isomer, Ϫ0.13
᎐
᎐
᎐
3206
J. Chem. Soc., Dalton Trans., 1998, 3199–3208

View Article Online
5
t
5
t
5
᎐
᎐
Table 3 Crystal data and structure refinement for [Ti(η -C5H4SiMe3)2(SC᎐CBu )2] 1a and [(η -C5H4SiMe3)(SC᎐CBu )Ti(µ-η :κ-P-C5H4PPh2)-
᎐
᎐
t
᎐
(µ-SC᎐CBu )Pt(C6F5)2] 8
᎐
1a
8
Empirical formula
M
C28H44S2Si2Ti
548.83
C57H60F10PPtS2SiTi
1307.22
a/Å
b/Å
11.470(6)
14.170(7)
12.904(2)
14.069(1)
c/Å
α/Њ
21.405(11)
94.04(3)
18.090(2)
70.18(1)
β/Њ
104.40(3)
106.26(4)
3198(3)
71.42(1)
74.91(1)
2885.6(6)
γ/Њ
U/Å3
Z
4
2
Dc/Mg mϪ3
1.140
1.505
F(000)
1176
0.487
1312
2.749
µ/mmϪ1
Crystal size/mm
θ Range for data collection/Њ
hkl Index ranges
Reflections collected
Independent reflections
Data/restraints/parameters
Goodness of fit on F2
R1, wR2 Final indices [I > 2σ(I)]
(all data)
0.46 × 0.13 × 0.08
2.05 to 23.53
Ϫ12 to 12, Ϫ15 to 15, 0–24
9746
9454 [R(int) = 0.1162]
6527/0/547
0.967
0.0902, 0.1122
0.2820, 0.1703
0.655 and Ϫ0.665
0.34 × 0.30 × 0.12
2.10 to 25.00
Ϫ14 to 1, Ϫ15 to 15, Ϫ20 to 20
10495
9885 [R(int) = 0.0788]
8882/0/685
1.049
0.0672, 0.1538
0.1217, 0.2064
2.599 and 1.748
Largest difference peak and hole/e ÅϪ3
2
Details in common: λ 0.71073 Å; triclinic, space group P1; full-matrix least-squares refinement on F ; R1 = Σ(|Fo| Ϫ |Fc|)/Σ|Fo|; wR2 = [Σw(Fo2 Ϫ Fc2)2/
¯
¹
ΣwFo ]²; goodness of fit = [Σw(Fo2 Ϫ Fc2)2/(Nobs Ϫ Nparam)]; w = [σ2(Fo) ϩ (g1P)2 ϩ g2P]Ϫ1; P = [max(Fo , 0 ϩ 2Fc2)]/3.
2
2
(CDCl3): at 20 ЊC, δ Ϫ114.1 (d, 1F), Ϫ115.05 (d, 1F), Ϫ115.6
(d, 1F), Ϫ117.5 (m, 1F) (Fo), Ϫ161.95, Ϫ161.99 (overlapping
of two triplets, 2Fp), Ϫ163.4 (m), Ϫ163.7 (m) (3F), Ϫ164.1 (m,
1F) (Fm); a similar pattern was observed at Ϫ50 ЊC. 31P-{1H}
NMR (CDCl3): δ 10.93 (s, C5H4PPh2).
and minimum transmission factors 0.983 and 0.680) and the
structure solved and refined as above. Regions of electron
density located at non-bonding distances were modelled as
interstitial solvent and refined with anisotropic displacement
parameters. In total, there were a quarter of a molecule of
n-hexane and a molecule of toluene per formula unit. Three
carbon atoms, refined at half occupancy, were found for the
hexane molecule, three other carbon atoms being generated by
symmetry. The toluene molecule was found in two regions, with
half occupancy in each and with the molecule disordered over
a symmetry center. There were four peaks of electron density
higher than 1 e ÅϪ3 in the final map, three located very close to
the platinum atom having no chemical meaning and the other
in the solvent area.
X-Ray crystallography
Complex 1a. Crystals of compound 1a suitable for X-ray
analysis were grown from a saturated pentane solution at
Ϫ20 ЊC. A deep brown needle-shaped crystal was fixed with
epoxy on top of a glass fiber and transferred to the cold stream
of the low temperature device of a Siemens STOE/AED2
automated four circle diffractometer. Crystal data and structure
refinement parameters are listed in Table 3. Data were collected
at 200 K by the θ–2θ method. Three check reflections measured
at regular intervals showed no loss of intensity at the end of
data collection. An empirical absorption correction based on
ψ scans was applied (maximum and minimum transmission
factors = 0.913, 0.841). The structure was solved by the
Patterson method. All non-hydrogen atoms were located
in succeeding Fourier difference syntheses and refined with
anisotropic thermal parameters. Hydrogen atoms were added at
calculated positions and assigned isotropic displacement
parameters equal to 1.2 or 1.5 times the Uiso value of their
respective apparent carbon atoms. Two molecules of the com-
pound were found per asymmetric unit. There was no electron
density higher than 1 e ÅϪ3 in the final map.
All calculations were carried out using the program
SHELXL 93.31
CCDC reference number 186/1093.
Acknowledgements
We thank the Dirección General de Investigación Científica y
Técnica (Spain) (Projects PB93-0250 and PB95-0003-C02-
01-02) and the University of La Rioja (Project API-98/B16)
for financial support.
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