Novel bonding modes between tetrathiafulvalenes (TTFS) and transition metal centers: π-bonding and covalent TTFSiMe2-MLn coordination to platinum

Article abstract of DOI:10.1002/ejic.200300930

Two novel strategies for coordinating TTF to transition metal centers have been developed. The reaction of tetrathiafulvalene (TTF) or 3,4- dimethyltetrathiafulvalene (o-Me₂TTF) with [Pt(η²- C₂H₄)(PPh₃)₂] leads to the π complexes [Pt(η²-TTF)(PPh₃)₂] (1) and [Pt(η²-o-Me₂TTF)(PPh₃)₂] (2), respectively. An X-ray crystallographic study performed on 2 confirmed, that TTFs act as a π acidic ligand. NMR studies revealed the existence, in solution, of an equilibrium between free and complexed TTF. Dilithiation of o-Me₂TTF and subsequent silylation with ClSiMe₂H afforded 3,4-dimethyl-3′,4′-(dimethylsilyl)tetrathiafulvalene (3), which has been structurally characterized. 3 reacts by oxidative addition across [Pt(η²-C₂H₄)(PPh₃)₂] to give [Pt{η²-o-(SiMe₂)₂-TTFMe ₂}(PPh₃)₂] (4), in which the TTF ligand is covalently ligated to platinum via SiMe₂ bridges. The redox properties of 3 and 4 have been investigated by cyclic voltammetry. Strong cathodic shifts of the two redox processes were observed for 4, implying the TTF core. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.

Full text of DOI:10.1002/ejic.200300930

FULL PAPER
Novel Bonding Modes between Tetrathiafulvalenes (TTFs) and Transition
Metal Centers: π-Bonding and Covalent TTFSiMe2؊MLn Coordination to
Platinum
Mathuresh N. Jayaswal,[a] Harmel N. Peindy,[a] Fabrice Guyon,*[a] Michael Knorr,*[a]
[b]
[b]
´
Narcis Avarvari, and Marc Fourmigue
Keywords: Platinum / Tetrathiafulvalene / pi interactions / Si ligands / X-ray diffraction
Two novel strategies for coordinating TTF to transition metal
3Ј,4Ј-(dimethylsilyl)tetrathiafulvalene (3), which has been
centers have been developed. The reaction of tetrathiafulva- structurally characterized. 3 reacts by oxidative addition
lene (TTF) or 3,4-dimethyltetrathiafulvalene (o-Me2TTF)
with [Pt(η2-C2H4)(PPh3)2] leads to the π complexes [Pt(η2-
TTF)(PPh3)2] (1) and [Pt(η2-o-Me2TTF)(PPh3)2] (2), respect-
across [Pt(η2-C2H4)(PPh3)2] to give [Pt{η2-o-(SiMe2)2-
TTFMe2}(PPh3)2] (4), in which the TTF ligand is covalently
ligated to platinum via SiMe2 bridges. The redox properties
ively. An X-ray crystallographic study performed on 2 con- of 3 and 4 have been investigated by cyclic voltammetry.
firmed, that TTFs act as a π acidic ligand. NMR studies re-
vealed the existence, in solution, of an equilibrium between
free and complexed TTF. Dilithiation of o-Me2TTF and sub-
Strong cathodic shifts of the two redox processes were ob-
served for 4, implying the TTF core.
( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
sequent silylation with ClSiMe2H afforded 3,4-dimethyl- Germany, 2004)
Introduction
From the research devoted to novel functionalized tetra-
thiafulvalenes (TTFs) has emerged, in the past few years,
the synthesis of derivatives incorporating substituents al-
lowing the coordination to transition metal fragments.[1]
Such molecules are particularly interesting in molecular
materials science for the elaboration of hybrid organic/inor-
ganic multifunctional materials.[2] Two main strategies have
been used for the synthesis of transition metal complexes
incorporating the TTF unit: (i) the functionalization of
Scheme 1. Schematic drawings of TTF derivatives used as ligands
TTFs with phosphane (A) or pyridine ligands (B) taking
advantage of the donor coordinating properties of these
substituents,[3] and (ii) the coordination of metal fragments
to the tetrathiolate or dithiolate tetrathiafulvalene
synthetic approaches for the development of organometallic
complexes incorporating the TTF unit. Firstly, since there
are no reports of studies devoted to the synthesis of tran-
sition metal complexes incorporating a π-ligated TTF unit,
it was tempting to evaluate the ability of TTF to act as a
π-acidic ligand. Our second strategy is based on the func-
tionalization of TTFs with SiR2ϪH moieties followed by
the oxidative addition of the SiϪH bond to the low valent
platinum center. In this paper we describe the synthesis and
characterization of the complexes [Pt(η2-TTF)(PPh3)2],
[Pt(η2-o-Me2TTF)(PPh3)2], and [Pt{o-(SiMe2)2TTFMe2}-
(PPh3)2], which, to the best of our knowledge, represent the
first examples of two novel bonding modes between TTF
derivatives and transition metal centers i.e. π bonding and
covalent bonding via an SiR2 bridge.
4Ϫ
2Ϫ
(TTFS4 and TTFS2 (C), respectively) via covalent me-
tal-ligand bonds (Scheme 1).[4]
Organometallic chemistry, however, offers additional
alternative routes to link a metal center to an organic sub-
strate, such as oxidative addition and π-coordination. Start-
ing with a Pt0(PPh3)2 fragment, we present herein two novel
[a]
´
´
Laboratoire de Chimie des Materiaux et Interfaces, Universite
´
´
de Franche-Comte, Faculte des Sciences et des Techniques,
16, Route de Gray, 25030 Besancon Cedex, France
¸
E-mail: michael.knorr@univ-fcomte.fr
[b]
´
Laboratoire de Chimie Inorganique, Materiaux et Interfaces,
´
Universite d’Angers, FRE 2447 CNRS,
2 Boulevard Lavoisier, 49045 Angers, France
2646
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
DOI: 10.1002/ejic.200300930
Eur. J. Inorg. Chem. 2004, 2646Ϫ2651

Novel Bonding Modes between TTFs and Transition Metal Centers
FULL PAPER
spectra indicate the exclusive coordination of the substi-
tuted TTF via the HϪCϭCϪH moiety. Thus, as observed
for 1, the proton NMR spectrum exhibits the signals for
the olefinic H atoms centered at δ ϭ 3.95 (3JP,H ϭ 2.4 Hz
Results and Discussion
Synthesis and Characterization of [Pt(η2-TTF)(PPh3)2] (1)
and [Pt(η2-o-Me2TTF)(PPh3)2] (2)
3
and JPt,H ϭ 61 Hz). The resonance of the Me groups ap-
The displacement of the ethylene ligand in [Pt(η2-
C2H4)(PPh3)2] by other olefins such as styrene, propenoates,
cycloalkenes, tetracyanoethylene, allenes, and other olefinic
compounds represents a convenient method of preparing
Pt0 complexes of the type [Pt(olefin)PPh3)2], since volatile
ethylene can be easily removed. The olefinic structure of
TTF led us to investigate its reactivity towards the reactive
starting material [Pt(η2-C2H4)(PPh3)2]. After stirring a
solution of [Pt(η2-C2H4)(PPh3)2] in toluene with a slight ex-
cess of TTF for 1 hour, concentration and addition of hep-
tane afforded bright yellow [Pt(η2-TTF)(PPh3)2] (1)
(Scheme 2). The coordination of TTF via the HϪCϭCϪH
bond can be inferred unambiguously from the NMR spec-
tra. Thus, in the proton NMR spectrum, two olefinic hydro-
gen atoms give rise to a broadened triplet at δ ϭ 3.96 with
pears as a singlet at δ ϭ 2.00. The additional singlets ob-
served at δ 6.30 and 1.96 stemming from 3,4-dimethyltetra-
thiafulvalene indicate, that as in the case of 1, an equilib-
rium occurs in solution between free and complexed 3,4-
dimethyltetrathiafulvalene (ratio 1:3.3). Cooling the solu-
tion resulted in the progressive increasing of the ratio of
complexed to uncomplexed TTF. The 31P{1H} NMR spec-
trum is very similar to that of 1 mentioned above, and re-
quires no special comments.
Molecular Structure of 2
Complex 2 crystallizes, with one solvent molecule (tolu-
¯
ene), in the triclinic space group P1. The molecular struc-
ture of the Pt0 complex is characterized by a trigonal planar
ligand arrangement with the alkene in the plane of the tri-
angle (Figure 1). The PtϪP distances [2.293(2) and 2.294(2)
3
3
a JP,H coupling of 2.5 Hz, and an additional JPt,H coup-
ling of 60.2 Hz. For comparison, the ethylene protons of
[Pt(η2-C2H4)(PPh3)2] resonate at a much higher field (δ ϭ
2.14 ppm), Furthermore, two singlets can be seen at δ ϭ
6.35 and 6.32 ppm in an approximate ratio of 1:1. These
resonances can be interpreted by the existence, in solution,
of an equilibrium between free and complexed TTF. This is
corroborated by the 31P{1H} NMR spectrum which dis-
plays two singlets at δ 27.8 and 16.1 in an approximate ratio
of 3:1, flanked by platinum satellites (1JP,Pt ϭ 3444 and
4083 Hz, respectively). The more intense system centered
at 27.8 ppm can be attributed to the (PPh3)2Pt fragment
complexed by the TTF. Note that the 31P{1H} NMR spec-
trum of the starting material [Pt(η2-C2H4)(PPh3)2] consists
˚
A] lie in the typical range observed in other [Pt(olef-
1
of a singlet at δ 35.8 with a JP,Pt coupling of 3741 Hz. The
second system centered at δ ϭ 16.1 ppm can be tentatively
assigned to the platinum fragment [Pt(PPh3)2], resulting
from the decomplexation of TTF, which may be stabilized
by weak interactions with the sulfur atoms. The reversible
coordination/decoordination of an olefin has already been
reported in the case of the complexes [Pt(η2-C2H4)(PCy3)2]
and [Pt(η2-norbornene)(PPh3)2].[5]
Scheme 2
In order to probe whether, in the case of an asymmetric
TTF derivative such as 3,4-dimethyltetrathiafulvalene (o-
Me2TTF), coordination to platinum occurs via the double
bound substituted with two hydrogens or, alternatively, via
the double bond substituted by the two methyl groups, we
also treated [Pt(η2-C2H4)(PPh3)2] with the 3,4-dimethylte-
trathiafulvalene. During the reaction, pure yellow [Pt(η2-
Figure 1. Top: molecular structure of 2 with labelling scheme; bot-
tom: view of the Pt-TTFMe2 core showing the boat conformation
o-Me2TTF)(PPh3)2] (2) precipitated (Scheme 2). The NMR of the TTFs; hydrogen atoms are omitted for clarity
Eur. J. Inorg. Chem. 2004, 2646Ϫ2651
www.eurjic.org
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2647

´
M. N. Jayaswal, H. N. Peindy, F. Guyon, M. Knorr, N. Avarvari, M. Fourmigue
FULL PAPER
Table 1. Comparison of selected geometric parameters between 2 and [Pt(PPh3)2(CH2ϭCH2)][7]
Complex
PϪPtϪP
103.55(8)
111.6(1)
PtϪP
CϪPtϪC
C(1)ϪC(2)
1.360(11)
1.43(1)
PtϪC
2
2.293(2)
2.294(2)
2.265(2)
2.270(2)
2.059
2.007
2.11(1)
2.12(1)
Pt(PPh3)2(CH2ϭCH2)
39.7(4)
in)(PPh3)2] complexes.[6] The PϪPtϪP angle [103.55(8)°] is between 2, and uncoordinated o-Me2TTF. As can be seen,
more acute than in the ethylene complex (Table 1). The the external CϪS bonds become longer upon coordination.
PtϪC bonds are significantly shorter in 2 in comparison This may be due to a reduction of conjugation within the
with the starting material [Pt(CH2ϭCH2)(PPh3)2]. The TTF fulvalene rings, which also leads to a shortening of the
˚
part is strongly folded along the S···S axis of each fulvalene, C(5)ϪC(6) bond length [1.305(11) vs. 1.338(4) A]. Con-
with values of 31.02(54)° for S(1)···S(2) and 16.52(21)° for versely, due to the interaction with the platinum, there is a
S(3)···S(4), while the central core [S(1Ϫ4), C(3) and C(4)] is significant lengthening of the C(1)ϪC(2) bond as observed
nearly planar (Figure 1, bottom). Thus, the boat confor- in almost all cases of coordinated olefins.[9] In contrast to
mation is much more pronounced in 2 compared with the the symmetrical structure of o-Me2TTF, C(1) and C(2) are
geometry of the free o-Me2TTF, for which angles of 0.6° not equivalent in 2: (i) the PtϪC bond lengths are quite
and 1.88° have been reported.[8] These deformations have different (Table 1), and (ii) the value observed for the
already been observed with several metal-coordinated TTF S(1)ϪC(1)ϪC(2) angle [112.3(6)°] suggests that the C(1)
derivatives (see for example ref.[3c]) but not with such mag- atom approaches a tetrahedral hybridization, whereas the
nitude. The increasing of the out-of-plane bend leads to sig- C(1)ϪC(2)ϪS(2) angle remains nearly unchanged upon
nificant changes for the other structural parameters. Table 2 complexation, indicating an sp2 hybridization for C(2)
provides a comparison of selected bond lengths and angles [119.9(6)°].
[8]
˚
Table 2. Selected bond lengths (A) and angles (°) for 3,4-dimethyltetrathiafulvalene, 2, and 3
3,4-Dimethyltetrathiafulvalene
2
3
S(1)ϪC(1)
S(1)ϪC(3)
S(2)ϪC(2)
S(2)ϪC(3)
C(3)ϪC(4)
C(1)ϪC(2)
S(3)ϪC(4)
S(3)ϪC(5)
S(4)ϪC(4)
S(4)ϪC(6)
C(5)ϪC(6)
C(5)ϪC(7)
C(6)ϪC(8)
C(1)ϪSi(1)
C(2)ϪSi(2)
1.743(4)
1.765(3)
1.739(4)
1.767(3)
1.340(4)
1.308(5)
1.753(3)
1.755(3)
1.762(3)
1.758(3)
1.338(4)
1.500(5)
1.503(5)
1.843(8)
1.729(9)
1.760(9)
1.768(8)
1.366(10)
1.360(11)
1.759(9)
1.781(9)
1.730(10)
1.772(8)
1.305(11)
1.527(10)
1.505(12)
1.762(3)
1.750(3)
1.765(2)
1.749(3)
1.357(4)
1.338(4)
1.751(3)
1.762(3)
1.751(3)
1.750(3)
1.328(4)
1.501(4)
1.506(4)
1.886(2)
1.873(3)
C(1)ϪS(1)ϪC(3)
C(2)ϪS(2)ϪC(3)
S(1)ϪC(1)ϪC(2)
C(1)ϪC(2)ϪS(2)
S(1)ϪC(3)ϪS(2)
S(2)ϪC(3)ϪS(4)
C(3)ϪC(4)ϪS(3)
C(4)ϪS(4)ϪC(6)
C(4)ϪS(3)ϪC(5)
S(3)ϪC(4)ϪS(4)
S(3)ϪC(5)ϪC(6)
C(6)ϪC(5)ϪC(7)
S(4)ϪC(6)ϪC(5)
C(5)ϪC(6)ϪC(8)
C(2)ϪC(1)ϪSi(1)
C(1)ϪC(2)ϪSi(2)
94.42(17)
94.31(17)
118.2(3)
118.7(3)
114.27(17)
122.9(3)
123.3(3)
95.51(15)
96.14(15)
113.89(17)
116.9(2)
127.0(3)
117.6(2)
126.8(3)
93.4(4)
91.3(4)
96.21(12)
96.37(12)
116.92(19)
116.5(2)
113.34(14)
122.6(2)
123.5(2)
95.46(13)
95.63(13)
114.14(14)
116.7(2)
127.0(3)
117.9(2)
112.3(6)
119.9(6)
114.9(4)
120.5(7)
120.9(7)
95.2(4)
94.3(4)
113.9(5)
117.0(6)
129.4(8)
117.2(7)
128.9(8)
126.7(3)
127.5(2)
128.76(19)
2648
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
Eur. J. Inorg. Chem. 2004, 2646Ϫ2651

Novel Bonding Modes between TTFs and Transition Metal Centers
FULL PAPER
Synthesis and Characterization of a Bis(silylated) Platinum- C2H4)(PPh3)2] in toluene to afford the platinum bis(silyl)
TTF Complex
complex [Pt{o-(Me2Si)2TTFMe2}(PPh3)2] (4) (Scheme 3).
The chelating coordination of the two SiMe2 groups on
One common strategy for the synthesis of substituted
TTFs takes advantage of the acidity of the TTF hydrogen
atoms.[10] Indeed, treatment with n equivalents of strong
bases such as LDA at low temperature affords TTFϪLin,
which can be treated with a variety of electrophiles. Using
this procedure, 3,4-dimethyltetrathiafulvalene was dilithi-
ated with 2 equivalents of LDA, then silylated with chloro-
dimethylsilane to give 3,4-dimethyl-3Ј,4Ј-(dimethylsilyl)-
tetrathiafulvalene (3) (Scheme 3).
1
each Pt center was confirmed by the H NMR spectrum
[singlet, δ ϭ Ϫ0.13 ppm, 3J(PtϪH) ϭ 22.1 Hz], and the
31P{1H} NMR spectrum [δ ϭ 30.0 ppm, 1J(PtϪP) ϭ
1716 Hz].
Cyclic voltammetric data for o-Me2TTF, 3, and 4 are
given in Table 3. In each case, two reversible or quasi revers-
ible single-electron oxidation waves were observed corre-
sponding to the oxidation of the TTF core (Figure 3). Sub-
stitution of the olefinic hydrogens in o-Me2TTF by the Si-
Me2H group induces a slight cathodic shift for the first oxi-
dation wave due to the inductive effect of the methyl group,
1/2
whereas E2 remains unchanged. More interesting is the
fact that the bis(silyl) complex 4 shows a strong cathodic
shift (nearly 0.2 V) for the two redox processes. This obser-
vation is contrary to the tendency reported in the case of
TTFs functionalized with phosphane or pyridine. The latter
always display shifts towards more anodic potentials upon
coordination.[3e,3j] This implies a strong interaction between
the TTF core and the metallic fragment. Note also that the
second oxidation wave in 4 appears not totally reversible at
standard scan rates (50Ϫ250 mV.sϪ1), since an additional
reduction peak was observed at Epc ഠ 0 V. This peak disap-
peared when the scan rate was faster (ϭ 1 V·sϪ1) or when
the potential was reversed just before the second oxidation
wave (Figure 3). Nevertheless the potential, and the reversi-
bility of the first electron transfer offer the possibility of
synthesizing open shell species from this organometallic
complex.
Scheme 3
Compound 3 was isolated in 72% yield as orange air-
stable solid, soluble in aliphatic hydrocarbons. Recrystalli-
zation from a concentrated hexane solution afforded single-
crystals suitable for an X-ray diffraction study. The ge-
ometry of 3 is shown in Figure 2, structural parameters are
given in Table 2. The framework of 3,4-dimethyltetrathia-
fulvalene is only slightly influenced by the substitution with
the dimethylsilyl functions. The geometry around the Si
atoms is essentially tetrahedral, with CϪSiϪC angle values
varying between 108.49(17) and 111.5(2)°. The C(1)ϪSi(1)
Table 3. Voltammetric data (E in V vs. Ag/0.1  AgClO4)
1/2
1/2
Compound
E1
E2
˚
and C(2)ϪSi(2) bond lengths [1.886(2) and 1.873(3) A] are
quite similar to that in (TTF)2SiMe2 [1.868(5) A].
DMTTF
3
4
ϩ 0.05
Ϫ0.01
Ϫ0.24
ϩ 0.53
ϩ 0.53
ϩ 0.34
[11]
˚
Figure 2. Molecular structure of 3
By taking advantage of the reactivity of the SiϪH bond
towards low valent transition metal centers, compound 3
seemed to be a promising precursor to covalently link a
platinum fragment to the TTF unit.[12] Thus, 3 reacts by
Figure 3. Cyclic voltammograms of 4 in CH2Cl2 solution on a plati-
oxidative addition with one equivalent of [Pt(η2- num electrode; scan rate: 100 mV sϪ1
Eur. J. Inorg. Chem. 2004, 2646Ϫ2651
www.eurjic.org
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2649

´
M. N. Jayaswal, H. N. Peindy, F. Guyon, M. Knorr, N. Avarvari, M. Fourmigue
FULL PAPER
ppm. 31P{1H} NMR: δ ϭ 27.8 (s, 1JPt,P ϭ 3450 Hz) ppm. 195Pt{1H}
NMR: δ ϭ Ϫ3206 (t, JPt,P ϭ 3450 Hz) ppm. C44H38P2PtS4
Conclusion
1
(952.05): calcd. C 55.51, H 4.02; found C 55.86, H, 4.17.
In summary, the bonding modes between tetrathiafulval-
enes and transition metal centers described in this paper
highlight the possible development of novel classes of TTF
derivatives using strategies from organometallic chemistry.
For example, insertion of unsaturated organic substrates
such as alkynes into the platinum-silicon bond may be an
original tool for introducing functionalization to the TTF
core.[13] On the other hand, the reactivity of the SiϪH bond
is not restricted to platinum, and generalization to other
Synthesis of 3,4-Dimethyl-3Ј,4Ј-(dimethylsilyl)tetrathiafulvalene (3):
A solution of o-Me2TTF (0.23 g, 1 mmol) in THF (20 mL) was
treated at Ϫ78 °C with LDA (2.5 mmol). The yellow precipitate
was stirred at Ϫ78 °C for 4 h, and then treated with chlorodime-
thylsilane (2.6 mmol). The reaction temperature was allowed to rise
slowly overnight to room temperature. The solvent was then re-
moved under reduced pressure, and the residue was extracted with
diethyl ether. After evaporation of the diethyl ether, the resultant
solid was recrystallized from hexane to give 3 as orange crystals
(250 mg, 72% yield). 1H NMR (CDCl3): δ ϭ 0.34 (d, 12 H, SiMe2,
3JH,H ϭ 3.8 Hz), 1.94 (s, 6 H, Me-TTF), 4.49 (h, 2 H, SiϪH) ppm.
IR (KBr): ν˜ ϭ 2163 (SiϪH) cmϪ1. C12H20S4Si2 (348.70): calcd. C
41.33, H 5.78; found C 41.45, H 5.75.
metal centers may provide
a family of transition
metalϪsilicon complexes in which the redox properties of
the TTF may be fine-tuned by the metallic fragment. Both
approaches, as well as potential applications in materials
science, are currently being pursued in our laboratories.
Synthesis of [Pt{o-(Me2Si)2TTFMe2}(PPh3)2] (4): To a solution of
3,4-dimethyl-3Ј,4Ј-(dimethylsilyl)tetrathiafulvalene (3) (105 mg,
0.3 mmol) in toluene (7 mL) was added [Pt(η2-C2H4)(PPh3)2]
(210 mg, 0.28 mmol) in toluene (7 mL). The resultant orange solu-
tion was stirred at room temperature for 2 h. The yellow complex
precipitated gradually from solution. The supernatant liquid was
Experimental Section
General Comments: All reactions were performed under dry nitro-
gen using standard Schlenk techniques. Solvents were dried by
standard methods, freshly distilled, and saturated with nitrogen
prior to use. TTF,[14] o-Me2TTF,[15] and [Pt(PPh3)2(C2H4)][16] were
prepared according to published procedures. The 1H, 31P{1H}, and
195Pt NMR spectra were recorded at 300.13, 81.01, and 42.95 MHz,
respectively, on a Bruker Avance 300 instrument. 195Pt chemical
shifts were externally referenced to aqueous K2PtCl4 with down-
field chemical shifts reported as positive. Elemental analyses were
decanted and the residue was washed with hexane (224 mg, 75%
yield). 1H NMR (CDCl3): δ ϭ Ϫ0.13 (s, 12 H, SiMe2, JPt,H
ϭ
2
22.1 Hz), 1.91 (s, 6 H, Me-TTF), 7.16Ϫ7.30 (m, 30 H, Ph) ppm.
1
31P{1H} NMR:
δ
ϭ
30.0 (s, JPt,P
ϭ 1716 Hz) ppm.
C48H48P2PtS4Si2 (1066.35) calcd. C 54.07, H 4.54; found C 54.40,
H 4.65.
´
performed at the Universite de Bourgogne with an EA 1108 Fi-
Table 4. X-ray structural data for 2 and 3
sons instrument.
Electrochemical Measurements: Voltammetric analyses were carried
out, at ambient temperature, in a standard three-electrode cell with
a Radiometer PGP 201 potentiostat. The electrolyte consisted of a
0.2  nBu4NPF6 solution in CH2Cl2. The working electrode was a
platinum disk electrode, and the auxiliary electrode was a platinum
wire. The reference electrode was a silver/silver ion electrode, Ag/
Agϩ (0.1  AgClO4 in acetonitrile) separated from the solution by
a sintered glass disk. After each measurement the reference was
checked against the ferrocene-ferrocenium couple (ϩ 0.16V relative
to this reference electrode).
Compound
2
3
Formula
Fw
Crystal size (mm)
T (K)
C47.5H42P2PtS4
998.08
0.32 ϫ 0.15 ϫ 0.08 0.77 ϫ 0.37 ϫ 0.19
293(2)
triclinic
C12H20S4Si2
348.70
293 (2)
triclinic
P1
Crystal system
Space group
¯
¯
P1
˚
a (A)
9.4534(19)
14.305(3)
16.968(3)
90.33(3)
101.71(3)
108.89(3)
2119.4(7)
2
1.564
3.616
998
0.71073
5.7661(12)
9.1180(18)
18.653(4)
89.05(3)
95.87(3)
107.54(3)
930.1(3)
2
1.245
0.623
368
0.71073
2.34Ϫ25.84
Ϫ7 Յ h Յ 6,
Ϫ11 Յ k Յ 11,
0 Յ l Յ 22
3298
˚
b (A)
˚
c (A)
α (deg)
β (deg)
γ (deg)
Synthesis of [Pt(η2-TTF)(PPh3)2] (1): To a solution of [Pt(η2-
C2H4)(PPh3)2] (375 mg, 0.5 mmol) in toluene (8 mL) was added
TTF (110 mg, 0.54 mmol). The solution was stirred at room tem-
perature for 1 h. Hexane was then added and the resultant solution
cooled to 4 °C. The solid, which formed, was collected by filtration,
washed with hexane and dried to provide 1 as an orange solid.
(393 mg, 85% yield).1H NMR (CDCl3): δ ϭ 3.96 (t br., 2 H, H-
3
˚
V (A )
Z
ρcalcd. (g cmϪ3
)
µ (mmϪ1
F(000)
λ (A)
)
˚
3
2
TTF, JH,P ϭ 2.5, JH,Pt ϭ 60.2 Hz), 6.32 (s, 2 H, H-TTF)
7.14Ϫ7.24 (m, 30 H, Ph). 31P{1H} NMR: δ ϭ 27.85 (s, JPt,P
ϭ
1
θ range, deg
Index ranges
1.87Ϫ25.79
Ϫ11 Յ h Յ 11,
Ϫ17 Յ k Յ 17,
0 Յ l Յ 20
3444 Hz) ppm. C42H34P2PtS4 (924.00): calcd. C 54.60, H 3.71;
found C 55.01, H, 3.60.
Synthesis of [Pt(η2-o-Me2TTF)(PPh3)2] (2): To a solution of [Pt(η2-
C2H4)(PPh3)2] (337 mg, 0.45 mmol) in toluene (8 mL) was added
o-Me2TTF (116 mg, 0.5 mmol). The solution was stirred at room
temperature for 0.5 h. The orange complex precipitated gradually
from solution. After cooling at 4 °C the supernatant liquid was
decanted, and the residue washed with hexane. (381 mg, 89%
yield).1H NMR (CDCl3): δ ϭ 2. 00 (s, 6 H, CH3), 3.95 (t br., 2 H,
No. of reflns. collected 7577
No. of ind. reflns.
Largest diff. peak
4162
Ϫ1.050/1.258
2248
Ϫ0.177/0.268
Ϫ3
˚
and hole, e(A
)
Final R indices[a]
R indices (all data)
GOF on F2
0.0446
0.1030
0.749
0.0397
0.0609
0.990
3
2
[a]
H-TTF, JH,P ϭ 2.4, JH,Pt ϭ 61.0 Hz), 7.16Ϫ7.24 (m, 30 H, Ph)
R(F) ϭ Σ|| Fo| Ϫ |Fc||/ Σ|Fo|.
2650
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
Eur. J. Inorg. Chem. 2004, 2646Ϫ2651

Novel Bonding Modes between TTFs and Transition Metal Centers
FULL PAPER
J. A. Belot, J. Seth, A. L. Rheingold, G. P. A. Yap, J. Mater.
Chem. 1995, 5, 1581Ϫ1587. [4e] S. B. Wilkes, I. R. Butler, A. E.
Underhill, M. B. Hursthouse, D. E. Hibbs, K. M. Abdul Malik,
J. Chem. Soc., Dalton Trans. 1995, 897Ϫ903. [4f] N. Le Narvor,
N. Robertson, E. Wallace, J. D. Kilburn, A. E. Underhill, P. N.
Bartlett, M. Webster, J. Chem. Soc., Dalton Trans. 1996,
823Ϫ828. [4g] A. Kobayashi, H. Tanaka, M. Kumasaki, H. To-
rii, B. Narymbetov, T. Adachi, J. Am. Chem. Soc. 1999, 121,
Crystallographic Data Collection and Structure Determinations of 2
and 3: Suitable crystals of 2 and 3 for X-ray diffraction were ob-
tained by crystallization from toluene and hexane, respectively. A
single-crystal of each compound was mounted in a glass capillary
using Araldite glue. Data were collected with a Stoe-IPDS dif-
fractometer, with graphite-monochromated Mo-Kα radiation (λ ϭ
˚
0.71073 A). Details are given in Table 4. A numerical absorption
10763Ϫ10771. [4h] H. Tanaka, Y. Okano, H. Kobayashi, W. Su-
correction was applied (FACEIT, Stoe). The structures were solved
by direct methods, and refined by full-matrix least-squares on F2
with anisotropic thermal parameters for all non-H atoms. H atoms
were included in calculated positions, and constrained to ride on
the parent C atoms. All calculations were performed with the
SHELTX package.[17] CCDC-226740 for [Pt(PPh3)2(o-Me2TTF)]
and -226741 for [o-Me2TTF(SiMe2H)2] contain the supplementary
crystallographic data for this paper. These data can be obtained
free of charge at www.ccdc.cam.ac.uk/conts/retrieving.html or from
the Cambridge Crystallographic Data Center, 12 Union Road,
Cambridge CB2 1EZ, UK [Fax: (internat.) ϩ44-1223-336-033; E-
mail: deposit@ccdc.cam.ac.uk].
[4i]
zuki, A. Kobayashi, Science 2001, 291, 285Ϫ287.
T. Naka-
mura, T. Takahashi, T. Yumoto, T. Akutagawa, T. Hasegawa,
[4j]
Chem. Lett. 2001, 134Ϫ135.
Matsubayashi, Inorg. Chim. Acta 1997, 254, 189Ϫ193.
Kubo, N. Nakano, H. Tamura, G. Matsubayashi, M. Nakam-
M. Nakano, A. Kuroda, G.
[4k]
K.
[4l]
oto, J. Organomet. Chem. 2003, 669, 141Ϫ143.
G.-Q. Bian,
J. Dai, Q.-Y. Zhu, W. Yang, Z.-M. Yan, M. Munakata, M.
Maekawa, Chem. Commun. 2002, 1474Ϫ1475.
[5] [5a]
H. C. Clark, G. Ferguson, M. J. Hampden-Smith, B.
Kaitner, H. Ruegger, Polyhedron 1988, 7, 1349Ϫ1353. [5b] P. G.
Gassman, I. G. Cesa, Organometallics 1984, 3, 119Ϫ128.
[6] [6a]
F. Caruso, M. Camalli, G. Pellizer, F. Asaro, M. Lenarda,
[6b]
Inorg. Chim. Acta 1991, 181, 167Ϫ176.
G. F de Sousa, C.
A. L. Filgueiras, P. B. Hitchcock, J. F. Nixon, Inorg. Chim. Acta
1997, 261, 217Ϫ200.
[7]
[8]
Acknowledgments
Financial support and a postdoctoral grant for M. N. Jajaswal
P. T. Chengu, S. C. Nyburg, Can. J. Chem. 1972, 50, 912.
´
C. E. Uzelmeier, M. Fourmigue, K. R. Dunbar, Acta Crys-
tallogr., Sect. C 1998, 54, 1047Ϫ1049.
`
from the Ministere de la Recherche et de la Technologie are
[9]
F. A. Cotton, G. Wilkinson, C. A. Murillo, M. Bochmann,
Advanced Inorganic Chemistry, 6th edn., John Wiley & Sons,
New York, 1999.
acknowledged.
[10]
[11]
[1]
D. C. Green, J. Org. Chem. 1979, 44, 1476Ϫ1479.
J. L. Segura, N. Martin, Angew. Chem. Int. Ed. 2001, 40,
´
M. Fourmigue, Y-S. Huang, Organometallics 1993, 12,
1372Ϫ1409.
[2]
797Ϫ802.
E. Coronado, J. R. Galan-Mascaros, C. J. Gomez-Garcia, V.
[12] [12a]
[12b]
W. Fink, Helv. Chim. Acta 1975, 58, 606Ϫ613.
C. Ea-
Laukhin, Nature 2000, 408, 447Ϫ449.
[3] [3a]
born, T. N. Metham, A. Pidcock, J. Organomet. Chem. 1973,
´
M. Fourmigue, P. Batail, Bull. Soc. Chim. Fr. 1992, 129,
[12c]
[3b]
63, 107Ϫ117.
C. Eaborn, B. Rattcliff, A. Pidcock, J. Or-
´
M. Fourmigue, C. E. Uzelmeier, K. Boubekeur, S.
29Ϫ36.
ganomet. Chem. 1974, 65, 174Ϫ180. [12d] M. Tanaka, Y. Uchim-
aru, H.-J. Lautenschlager, Organometallics 1991, 10, 16Ϫ18.
L. Bartley, K. R. Dunbar, J. Organomet. Chem. 1997, 529,
343Ϫ350. [3c] C. E. Uzelmeier, S. L. Bartley, M. Fourmigue, R.
´
[12e]
U. Schubert, C. Müller, J. Organomet. Chem. 1991, 418,
Rogers, G. Grandinetti, K. R. Dunbar, Inorg. Chem. 1998, 37,
C6ϪC8. [12f] D. F. Mullica, E. L. Sappenfield, M. J. Hampden-
[3d]
1833Ϫ1840.
B. W. Smucker, K. R. Dunbar, J. Chem. Soc.,
[12g]
[3e]
Smith, Polyhedron 1991, 10, 867Ϫ872.
M. Knorr, F. Gu-
Dalton Trans. 2000, 1309Ϫ1315.
N. Avarvari, D. Martin,
yon, I. Jourdain, S. Kneifel, J. Frenzel, C. Strohmann, Inorg.
Chim. Acta 2003, 350, 455Ϫ466.
´
M. Fourmigue, J. Organomet. Chem. 2002, 643Ϫ644, 292Ϫ300.
[3f]
P. Pellon, G. Gachot, J. Le Bris, S. Marchin, R. Carlier, D.
[13] [13a]
[3g]
M. Tanaka, Y. Uchimaru, Bull. Soc. Chim. Fr. 1992, 129,
Lorcy, Inorg. Chem. 2003, 42, 2056Ϫ2060.
F. Iwahori, S.
[13b]
667Ϫ675.
P. Braunstein, M. Knorr, J. Organomet. Chem.
Golhen, L. Ouahab, R. Carlier, J. P. Sutter, Inorg. Chem. 2001,
40, 6541Ϫ6542. [3h] F. Setifi, L. Ouahab, S. Golhen, Y. Yoshida,
1995, 500, 21Ϫ38.
[14]
[15]
[3i]
A. J. Moore, M. R. Bryce, Synthesis 1997, 407Ϫ409.
G. Saito, Inorg. Chem. 2003, 42, 1791Ϫ1793.
S. Serroni, F. Puntoriero, F. Loiseau, L. De Cola, C. J. Klever-
laan, J. Becher, A. P. Sorensen, P. Hascoat, N. Thorup, Chem.
S. Campagna,
´
F. Gerson, A. Lamprecht, M. Fourmigue, J. Chem. Soc., Perkin
Trans. 2 1996, 1409Ϫ1414.
[16]
[17]
[3j]
C. D. Cook, G. S. Jauhal, J. Am. Chem. Soc. 1968, 90,
Eur. J. 2002, 8, 4461Ϫ4469.
S. X. Liu, S. Dolder, P. Franz,
1464Ϫ1467.
A. Neels, H. Stoeckli-Evans, S. Decurtins, Inorg. Chem. 2003,
42, 4801Ϫ4803.
G. M. Sheldrick, SHELTX, Programs for the Refinement of
Crystal Structures, University of Göttingen, Germany, 1997.
Received December 12, 2003
[4] [4a]
R. R. Schumaker, E. M. Engler, J. Am. Chem. Soc. 1980,
[4b]
102, 6651Ϫ6652.
H. Poleschner, W. John, F. Hoppe, E.
[4c]
Fanghänel, S. Roth, J. Prak. Chem. 1983, 6, 957Ϫ975.
R.
Early View Article
Published Online May 5, 2004
D. McCullough, J. A. Belot, A. L. Rheingold, G. P. A. Yap, J.
Am. Chem. Soc. 1995, 117, 9913Ϫ9914. [4d] R. D. McCullough,
Eur. J. Inorg. Chem. 2004, 2646Ϫ2651
www.eurjic.org
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2651