Tetrathiafulvalenyl-acetylacetonate complexes of difluoroboron

Article abstract of DOI:10.1016/j.tet.2009.05.041

A series of tetrathiafulvalene (TTF) derivatives functionalized by one or two β-diketonatoboron difluoride groups were synthesized through the addition of borontrifluoride to TTF substituted by one or two acetylacetone functions. The influence of the β-di

Full text of DOI:10.1016/j.tet.2009.05.041

Tetrahedron 65 (2009) 6123–6127
Contents lists available at ScienceDirect
Tetrahedron
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Tetrathiafulvalenyl-acetylacetonate complexes of difluoroboron
*
Michel Guerro, Thierry Roisnel, Dominique Lorcy
ˆ
Sciences Chimiques de Rennes, UMR 6226 CNRS-Universite´ de Rennes 1, Campus de Beaulieu, Bat 10A, 35042 Rennes cedex, France
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 9 April 2009
Received in revised form 12 May 2009
Accepted 18 May 2009
Available online 23 May 2009
A series of tetrathiafulvalene (TTF) derivatives functionalized by one or two b-diketonatoboron difluoride
groups were synthesized through the addition of borontrifluoride to TTF substituted by one or two
acetylacetone functions. The influence of the -diketonatoboron difluoride moiety on the redox prop-
erties of the TTF has been investigated by cyclic voltammetry.
b
Ó 2009 Elsevier Ltd. All rights reserved.
Keywords:
Tetrathiafulvalene
b
-Diketonate ligand
Boron difluoride
Redox behaviour
1. Introduction
neighbouring molecules plays an important role in the self as-
semblies of such complexes.10 Herein, we report the synthesis of
For more than three decades, tetrathiafulvalene (TTF) and its
derivatives have focused a lot of attention as precursors of molec-
ular conductors.1 As these observed properties are the results of
interacting TTF radical ion species, numerous functionalization of
this electroactive TTF framework has been realized with the aim of
generating increased interactions.1 Within this frame, a very active
and recent research area trends towards the elaboration of TTF
functionalized by coordination function due to strong potentialities
of this type of electroactive ligand.2 Accordingly, we recently in-
vestigated the synthesis of acetylacetone substituted TTF either
connected through a sulfur atom to the donor core3 or directly
linked to the TTF moiety.4 These acetylacetone TTF derivatives have
a series of b-diketonatoboron difluoride TTF together with the
electrochemical investigations carried out on these derivatives to
study the influence of the BF2 moiety on the donating ability of the
TTF core. In addition, the structural properties of a
complex are presented.
b-diketonate BF2
2. Results and discussion
In order to synthesize substituted TTF two main strategies are
often followed. The first one consists in preparing the functional-
ized precursors and then to form the TTF skeleton essentially by
self-coupling of these precursors while the second approach
requires the formation of the TTF core and then the functionaliza-
shown their efficiency for the generation of
b-diketonate ions,
tion.11 Therefore, in order to prepare the TTF functionalized by a
b-
which form stable chelate complexes with various transition metal
derivatives such as Zn, Ni, Mn and Cu.2–4,5,6,7 Moreover, TTF
substituted by a thioacetylacetone substituent can also be trans-
formed into another electroactive pyrazole ligand, which forms
stable complexes with Re.8 In continuation of our studies on ace-
tylacetonate TTF, we investigated the chelating ability of this ligand
towards difluoroboron moiety. This work was motivated by the fact
diketonate complex of difluoroboron, we investigated first the
synthesis of the corresponding moiety, the dithiole-2-thione, as
this type of derivative is known to be excellent precursor of TTF.11
For that purpose, we used the dithiole-2-thione 112 bearing a cya-
noethylthio-protected group as starting material (Scheme 1). The
cyanoethyl group can be easily removed in the presence of
CsOH$H2O13 and the free thiolate can be further alkylated with 3-
chloropentane-2,4-dione to give in good yield the dithiole 2. The
corresponding difluoroboron complex 3 was prepared by adding an
excess of borontrifluoride diethyletherate (BF3$OEt2) to a solution
of dithiole 2 in dichloromethane. According to the same synthetic
strategy, we also prepared the corresponding dithiol-2-ones 4–6,
thanks to the conversion of the dithiole-2-thione 1 into the corre-
sponding dithiole-2-one 4 by treating 1 with Hg(OAc)2 in the
presence of CH3CO2H (Scheme 1).
that
b-diketonate complexes of boron difluorides are known as
potential electron-transporting materials9 and to the best of our
knowledge no association of the TTF electroactive core with this
type of complex has been reported so far. Moreover, it has been
observed also that C–H/F hydrogen bonding between two
* Corresponding author. Fax: þ33 2 23 23 67 38.
E-mail address: dominique.lorcy@univ-rennes1.fr (D. Lorcy).
0040-4020/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2009.05.041

6124
M. Guerro et al. / Tetrahedron 65 (2009) 6123–6127
Me
O
Me
Me
O
O
Me
S(CH2)2CN
Me
S
BF2
Me
S
O
CsOH.H2O
Et2O.BF3
Me
S
S
S
S
S
S
ClCH(COCH3)2
X
X
X
1 X = S
2 X = S
3 X = S
AcOH
Hg(OAc)2
4 X = O
5 X = O
6 X = O
Scheme 1.
Single crystals of the difluoroboron complex 3 were obtained,
suitable for X-ray structure analysis. The ORTEP diagram of 3 is
shown in Figure 1 and selected bond lengths and distances are
listed in figure caption. As seen in Figure 1, the dithiole ring is
planar while the dioxaborine cycle is not planar. Indeed the diox-
aborine cycle exhibits a boat conformation with a plane formed by
C(12)–O(15)–O(14)–C(10) and the cycle is puckered along the
O14/O15 vector and the C(12)/C(10) one with angles of about 33ꢀ
and 11ꢀ, respectively. Therefore this distorted structure strongly
differs either from the one observed for diphenyl,14 dipyrrole15 or
disymetrically16 substituted derivative where the dioxaborine cy-
cles are planar or from the quasi planar structure observed for the
difluoroborondimethylacetonate.17 Within this cycle in 3 the car-
bonyl bond lengths are of similar value as well as the C–C bond
lengths. These C–O and C–C bond distances are of comparable value
with those observed in the thioacetylacetone moiety of the
TTFSacacH 7b where the H atom is shared symmetrically with the O
All the attempts to realize the TTF skeleton through the phos-
phite coupling of the dithiole-2-thione 2 and 3 were unsuccessful
as well as with the dithiol-2-ones 5 and 6. Therefore, we choose the
second approach to form the TTF
b-diketonate difluoroboron
complexes, which consists in chelating the difluoroboron in the last
synthetic step. First, we realized the acetylacetone functionalized
TTF 7a–c3 and then we added an excess of BF3$OEt2 to a CH2Cl2
solution of these TTF 7a–c under inert atmosphere (Scheme 2). TTF
8c, as TTF 7c, was obtained as a mixture of two isomers, cis and
trans, which could not be separated upon chromatography.
Me
Me
Me
Me
O
O
O
O
R1
S
S
R1
S
S
BF2
S
S
Et2O.BF3
CH2Cl2
S
S
S
S
atoms with a complete
p-delocalization (C–O: 1.284(4), 1.299(5)
and C–C: 1.410(5), 1.406(5)).3b Moreover this dithiole 3, in the solid
state, forms supramolecular network due to weak intermolecular
C–H/F–B interactions between C(13)–H/F(17) 2.799(2) Å and
C(5)–H/F(17) 2.728(1) Å, which are shown in Figure 2.18
R2
R1
R2
R1
8
7
a R1 = R2 = Me
b R1 = R2 = SMe
c R1 = Me R2 = SacacH
Scheme 2.
C13
C12
F18
O15
C5
We also prepared the bis substituted TTF 7d, where the two
SacacH groups are located on the same dithiole ring, using bis-
(cyanoethylthio)-bis(methylthio)TTF 919 as precursor (Scheme 3).
The two thiolate groups can be easily recovered by treating TTF 9
with 2 equiv of CsOH$H2O and then further alkylated with 3-
chloropentane-2,4-dione to give TTF 7d. Addition of an excess of
borontrifluoride diethyletherate (BF3$OEt2) to a solution of TTF 7d
in dichloromethane affords TTF 8d. The target molecules 8a–d are
obtained as air stable derivatives after purification by column
chromatography on silica gel.
The influence of the difluoroboron moiety on the electron do-
nating ability of these TTFs 8a–d was analyzed by cyclic voltam-
metry. They all exhibit two reversible monoelectronic oxidation
waves, a typical redox behaviour for TTF. The oxidation potentials
are collected in Table 1 together with the oxidation potentials of the
TTF precursors 7a–d. As seen in Table 1, when passing from the
acetylacetone substituent in TTFs 7a–d to the diketonate difluoro-
boron complex in TTF 8a–d the oxidation potentials are shifted
towards more positive potentials indicating the electron with-
drawing effect of the dioxaborine cycle on the TTF core. Also, in all
the cases the potential difference between the second and the first
oxidation potential is decreased. It is worth noting that on cathodic
scan no reduction process was observed as in the case tert-butyl
borondifluoridediketonate18 or with bis(dioxaborine)fluorene
derivatives.20
S8
C9
O14
C10
C11
B16
F17
C4
C6
S3
C2
S7
S1
Figure 1. ORTEP diagram of dithiole 3. Hydrogen atoms are omitted for clarity. Ellip-
soids are drawn at 50% probability. Selected bond lengths (Å): C(9)–C(10) 1.407(3),
C(9)–C(12) 1.401(3), C(10)–O(14) 1.294(2), C(12)–O(15) 1.291(2), O(14)–B(16) 1.495(2),
O(15)–B(16) 1.502(2), B(16)–F(17) 1.373(2), B(16)–F(18) 1.363(2).
We also investigated the synthesis of vinylogous TTF (TTFV)
substituted by two thioacetylacetone groups. This was realized
starting from TTFV 10 substituted by two cyanoethylthio-protected
thiolate groups (Scheme 4).12 Treatment of 10 with CsOH$H2O
Figure 2. View of the weak intermolecular C–H/F–B interactions.

M. Guerro et al. / Tetrahedron 65 (2009) 6123–6127
6125
Me
Me
Me
Me
Me
Me
Me
Me
O
O
O
O
O
O
O
O
NC(H2C)2
S
S
(CH2)2CN
BF2
F2B
S
S
S
S
S
S
S
S
S
S
CsOH
ClCH(COCH3)2
Et2O.BF3
CH2Cl2
S
S
S
S
S
S
MeS
SMe
MeS
SMe
MeS
SMe
8d
9
7d
Scheme 3.
Table 1
It is worth mentioning that b-diketonatoboron difluoride com-
Oxidation potentials of the TTFs 7a–d and TTFs 8a–d, E in V versus SCE, Pt working
electrode with 0.1 M n-Bu4NPF6 scanning rate100 mV sꢁ1
plexes are known to exhibit interesting spectroscopic features, such
as high molar absorptivity and fluorescence intensities.22 However,
it should be pointed out that only the boron difluoride complexes
with aromatic structure, like dibenzoyl(methano)boron difluoride,
exhibited such characteristics while the complex of acetylacetonate
gave no fluorescence.22 Nevertheless, being aware that structural
parameters might modify such emissive properties, we in-
compound
E1
E2
DE
7a
8a
7b
8b
7c
8c
7d
8d
11
12
0.33
0.42
0.52
0.58
0.48
0.57
0.55
0.64
0.32
0.47
0.78
0.86
0.83
0.88
0.87
0.91
0.85
0.91
0.45
0.55
450
440
310
300
390
340
300
270
130
80
vestigated the various b-diketonatoboron difluoride TTFs, the oxi-
dized TTFs (8a–c)(PF6), generated by the addition of 1 equiv of
NOPF6 to a solution of TTF 8a–c and dithiole derivatives prepared
but none of them shows fluorescence when excited at the wave-
length of the absorption maximum.
3. Conclusion
allowed the deprotection of the two thiolate functions, which are
further alkylated with 3-chloropentane-2,4-dione. According to
this strategy, 11 was obtained in 80% yield as a mixture of three
isomers (ZZ/EE/ZE), which are observed on 1H NMR spectra but
could not be separated by column chromatography. Addition of an
excess of BF3$OEt2 to a solution of 11 in CH2Cl2 allowed us to isolate
TTFV 12 also as a mixture of three isomers. The analysis of these
two TTFV 11–12 by cyclic voltammetry shows that they exhibit two
close reversible monoelectronic oxidation waves (Table 1). The
electron withdrawing effect of the dioxaborine ring can be ob-
served here by a positive shift of the oxidation potentials and also
by the decrease of the oxidation potential difference between the
first and the second oxidation potentials (Table 1). A significant
In summary, we prepared
a series of b-diketonatoboron
difluoride dithioles and TTF derivatives by adding in the last syn-
thetic step the Lewis acid reagent. Even if none of this compound
exhibits fluorescence properties, we demonstrated the feasibility of
this approach in order to reach
derivatives. Future investigations will be devoted to the synthesis of
TTF substituted by aromatic -diketonatoboron difluorides in order
b-diketonatoboron difluoride TTF
b
to observe fluorescence properties, which could be modulated by
the redox state of the TTF.
4. Experimental section
4.1. General
decrease of the D
E and a stronger enhancement of E1 between TTFV
11 and 12 are observed compared to the other TTF derivatives
(Table 1). This redox behaviour has its origin in the fact that, for all
TTFV, molecular movements are concerted with electron transfer,
which induces a compression of potentials especially when in-
creasing the withdrawing strength of the substituent.21
1H NMR, 13C NMR and 11B spectra were recorded on a Bruker
Avance 300 III spectrometer with tetramethylsilane as internal
reference. Chemical shifts are reported in parts per million. Mass
spectra and elemental analysis results were performed by the
Centre de Mesures Physiques de l’Ouest, Rennes. Melting points
were measured using a Kofler hot stage apparatus and are un-
corrected. Cyclic voltammetry was carried out on a 10ꢁ3 M solution
of the compounds in dichloromethane, containing 0.1 M n-
Bu4NPF6 as supporting electrolyte. Voltammograms were recorded
at 0.1 V sꢁ1 on a platinum disk electrode (A¼1 mm2). The potentials
were measured versus Saturated Calomel Electrode.
O
Me
O
NC(H2C)2S
Me
Me
S
S
Me
CsOH
ClCH(COCH3)2
S
S
S
2
2
4.2. Synthesis
11 (ZZ/EE/ZE)
10 (ZZ/EE/ZE)
4.2.1. 3-[(5-Methyl-2-thioxo-1,3-dithiol-4-yl)thio]pentane-
2,4-dione (2)
Me
O
Me
Me
Me
S
O
S
BF2
To a solution of cyanoethylthiodithiole-2-thione 1 (230 mg,
1 mmol) in 10 mL of DMF was added under argon a solution of
CsOH$H2O (180 mg, 1.1 mmol) in 3 mL of MeOH. The mixture was
allowed to stir for 2 h at rt after which 3-chloropentane-2,4-dione
(0.125 mL, 1.1 mmol) was added. The reaction mixture was stirred
for 5 h and then the solvents were evaporated. The residue was
extracted with CH2Cl2 and washed 2ꢂ20 mL with water. The or-
ganic layer was dried over MgSO4 and evaporated. Chromatography
Et2O.BF3
CH2Cl2
F2B
S
S
O
O
S
S
Me
Me
12 (ZZ/EE/ZE)
Scheme 4.

6126
M. Guerro et al. / Tetrahedron 65 (2009) 6123–6127
over silica gel using CH2Cl2 as eluent afforded 2 as a brown powder,
a dark-red powder. Mp¼142 ꢀC; 1H NMR (300 MHz, CDCl3)
d 2.43 (s,
yield 60%, mp¼115 ꢀC; 1H NMR (300 MHz, CDCl3)
d
2.30 (s, 3H,
6H, CH3), 2.49 (s, 12H, CH3), 17.23(s, 2H, OH); 13C NMR (75 MHz,
CH3), 2.43 (s, 6H, CH3), 17.16 (s, 1H, OH); 13C NMR (75 MHz, CDCl3)
CDCl3) d 19.1, 24.9, 102.4, 108.6, 111.6, 122.7, 127.5, 197.4; IR n
d
14.5, 24.7, 102.7, 131.8, 135.8, 197.4, 210.4; HRMS calcd for
C]O¼1556, 1417 cmꢁ1
.
C9H10O2S4: 277.95637, found: 277.95637.
4.2.7. General procedure for the synthesis of TTF(acacBF2) (8)
4.2.2. Difluoroboron dimethyldiketonate dithiole (3)
To a solution of TTF(acacH) 7 (0.5 mmol) in dried and degassed
CH2Cl2 (15 mL), under inert atmosphere, was added BF3$OEt2
(10 mmol) and the resulting solution was stirred at rt for 3 h. The
organic phase was washed with water 2ꢂ20 mL and dried over
MgSO4. The solvent was removed and the residue was purified by
silica gel column chromatography using Et2O as eluent. Al the TTF
An excess of BF3$OEt2 (0.8 mL,10 mmol) was added to a solution
of dithiole 2 (116 mg, 0.5 mmol) in 5 mL of dry and degassed CH2Cl2
under inert atmosphere. The reaction mixture was stirred at rt for
3 h. The organic phase was washed with water 2ꢂ20 mL and dried
over MgSO4. The dithiole 3 was obtained as a yellow powder after
column chromatography using CH2Cl2 as eluent in 66% yield,
b-diketonate complexes of difluoroboron were obtained as red
mp¼148 ꢀC; 1H NMR (300 MHz, CDCl3)
d
2.37 (s, 3H, CH3), 2.66 (s,
powders.
6H, CH3); 13C NMR (75 MHz, CDCl3)
d
14.8, 24.7, 105.2, 127.0, 140.0,
Me3TTFS(acacBF2) (8a): yield 90%, mp¼200 ꢀC; 1H NMR
197.1(t, J3CF¼1.5 Hz), 209.2; 11B NMR (96 MHz, CDCl3)
d
ꢁ0.61; UV–
(300 MHz, CDCl3)d1.95 (s, 6H, CH3), 2.19(s, 3H, CH3), 2.65(s, 6H, CH3);
vis
(CH2Cl2)
l
¼379 nm
(
3
¼11,860 L molꢁ1 cmꢁ1),
287
11B NMR (96 MHz; CDCl3)
d
ꢁ0.56; HRMS calcd for C14H15O2F2BS5:
(3
¼9700 L molꢁ1 cmꢁ1), 237 (
3
¼6830 L molꢁ1 cmꢁ1); HRMS calcd
423.97368, found: 423.9730. Anal. Calcd for C14H15O2F2BS5: C, 39.62;
H, 3.56; S, 37.78. Found: C, 39.48; H, 3.60; S, 38.16.
for C9H9O2F2BS4: 325.9546, found: 325.9562.
(MeS)3TTFSacacBF2 (8b): yield 56%, mp¼154 ꢀC; 1H NMR
4.2.3. 3-[(5-Methyl-2-oxo-1,3-dithiol-4-yl)thio]propanenitrile (4)
To a solution of dithiole-2-thione 1 (2.24 g, 9.6 mmol) in 10 mL
of CHCl3 was added 4 mL of CH3CO2H and Hg(OAc)2 (8 g, 25 mmol).
The reaction mixture was stirred for 2 h at rt and then filtered on
short Celite column, which was washed with 30 mL of CHCl3. The
organic phase was washed 2ꢂ30 mL with water, then with a satu-
rated solution of NaHCO3 (30 mL) and with 30 mL of water. The
organic phase was dried over MgSO4 and then the solvent was
removed under reduced pressure. The residue was chromato-
graphed over silica gel using Et2O/pretoleum ether as eluent (50/
50). The dithiole-2-one was obtained as a yellow oil in 68% yield; 1H
(300 MHz, CDCl3) d 2.41 (s, 3H, CH3), 2.42 (s, 3H, CH3), 2.44 (s, 3H,
CH3), 2.67 (s, 6H, CH3); 13C NMR (75 MHz, CDCl3)
d 19.2, 19.4, 24.9,
105.4, 108.1, 113.6, 125.1, 126.7, 126.8, 128.1, 196.9; 11B NMR (96 MHz,
CDCl3)
d
ꢁ0.55; UV–vis (CH2Cl2)
l
¼283 nm (
3
¼21,650 L molꢁ1 cmꢁ1);
HRMS calcd for C14H15O2F2BS8: 519.8898, found: 519.8936. Anal.
Calcd for C14H15O2F2BS8: C, 32.30; H, 2.90 Found: C, 31.94; H, 2.79.
(Me)2TTF(SacacBF2)2 (8c): yield 39%, mp¼246 ꢀC; 1H NMR
(300 MHz, CDCl3)
(75 MHz, CDCl3)
d
2.19 (s, 6H, CH3), 2.64 (s, 12H, CH3); 13C NMR
d
15.0, 24.7, 109.3, 115.1, 127.1, 131.9, 133.5, 196.7;
11B NMR (96 MHz, CDCl3)
d
ꢁ0.57; UV–vis (CH2Cl2)
l
¼320 nm
(
3
¼16,070 L molꢁ1 cmꢁ1), 292
(3
¼25,300 L molꢁ1 cmꢁ1); HRMS
NMR (300 MHz, CDCl3)
d
2.44 (s, 3H, CH3), 2.70 (t, 2H, CH2), 2.99 (t,
15.8, 18.5, 31.6, 116.0, 117.4,
calcd for C18H18O4F4B2S6: 587.9651, found: 587.9639.
2H, CH2); 13C NMR (75 MHz, CD3Cl)
d
(MeS)2TTF(SacacBF2)2 (8d): yield 30%, mp¼196 ꢀC; 1H NMR
138.5, 189.7. Anal. Calcd for C7H7NOS3: C, 38.69; H, 3.25; N. 6.44.
Found: C, 38.82; H, 3.24; N. 6.45.
(300 MHz, CDCl3)
(75 MHz, CDCl3)
d
2.43 (s, 6H, CH3), 2.72 (s, 12H, CH3); 13C NMR
d
19.2, 24.9,104.4, 122.7, 127.4, 127.6, 133.5,197.0; 11
B
NMR (96 MHz, CDCl3)
d
ꢁ0.55; UV–vis (CH2Cl2)
l
¼291 nm
4.2.4. 3-[(5-Methyl-2-oxo-1,3-dithiol-4-yl)thio]pentane-
2,4-dione (5)
(3
¼28,550 L molꢁ1 cmꢁ1); HRMS calcd for C18H18O4F4B2S8: 651.9093,
found: 651.9080.
Similar procedure as the one described above for the synthesis
of dithiole 2 using dithiole 4 (1.43 g, 6.6 mmol) as starting material,
CsOH$H2O (1.2 g, 7.2 mmol) and 3-chloro-2,4-pentanedione
(7.2 mmol, 0.82 mL). The dithiole 5 was obtained in 53% yield as
4.2.8. Synthesis of TTFV(SacacH)2 (11)
To a solution of TTFV 10 (650 mg, 1.1 mmol) in 25 mL of DMF was
added under argon a solution of CsOH$H2O (1.5 g, 8.8 mmol) in 3 mL
of MeOH. The mixture was allowed to stir for 3 h at rt after which 3-
chloropentane-2,4-dione (0.51 mL, 4.4 mmol) was added. The re-
action mixture was stirred for 3 h and then the solvents were evap-
orated. The residue was extracted with CH2Cl2 and washed 2ꢂ20 mL
with water. The organic layer was dried over MgSO4 and evaporated.
Chromatography over silica gel using CH2Cl2/ethylacetate (4/1) as
eluent afforded 11 as a yellow powder, yield 80%, mp¼80 ꢀC; 1H NMR
a light pink powder, mp¼74 ꢀC; 1H NMR (300 MHz, CDCl3)
d 2.33 (s,
3H, CH3), 2.42 (s, 6H, CH3), 17.1 (s, 1H, OH); 13C NMR (75 MHz,
CDCl3)
d 15.1, 24.7, 102.9, 121.7, 126.2, 189.7, 197.4. Anal. Calcd for
C9H10O3S3: C, 41.20; H, 3.84. Found: C, 41.28; H, 3.89.
4.2.5. Difluoroboron dimethyldiketonate dithiole-2-one (6)
Similar procedure as the one described above for the synthesis of
dithiole 3 using dithiole 5 (1.26 g, 1 mmol) as starting material. The
dithiole 6 was obtained in 43% yield as a white powder, mp¼146 ꢀC;
(300 MHz, CDCl3)
d 2.10 (s, 6H, CH3), 2.34 (s, 6H, CH3), 2.42 (s, 6H,
CH3), 7.20–7.44 (m, 10H, Ar), 17.1 (m, 2H, OH); HRMS calcd for
C32H30O4S6: 670.0468, found: 670.0521. Anal. Calcd for C32H30O4S6:
C, 57.28; H, 4.51; S, 28.67. Found: C, 56.52; H, 4.58; S, 28.67.
1H NMR (300 MHz, CDCl3)
d
2.37 (s, 3H, CH3), 2.66 (s, 6H, CH3); 13
C
B
NMR (75 MHz, CDCl3)
NMR (96 MHz, CDCl3)
d
15.3, 24.6,105.4,117.9,130.5,188.4,197.0; 11
d
0.06. Anal. Calcd for C9H9O3F2BS3: C, 34.85;
H, 2.92; S, 31.01. Found: C, 35.07; H, 2.85; S, 31.51.
4.2.9. Synthesis of TTFV(SacacBF2)2 (12)
Similar procedure as the one described above for the synthesis
of TTF 8. TTFV 12 was obtained as a brown powder in 34% yield;
4.2.6. Synthesis of TTF(acacH) (7d)
To a solution of biscyanoethylthio bis(methylthio)-TTF (460 mg,
1 mmol) in 8 mL of DMF was slowly added under argon a solution of
CsOH$H2O (370 mg, 2.2 mmol) in 3 mL of MeOH. The mixture was
allowed to stir for 5 h at rt after which 3-chloro-2,4-pentanedione
(0.25 mL, 2.2 mmol) was added. The reaction mixture was stirred
for 3 h at rt and the solvents were removed in vacuo. The resulting
oil was extracted with CH2Cl2, the organic phase was washed with
water 3ꢂ20 mL, dried over MgSO4 and chromatographed over silica
using CH2Cl2/PE (2/1) as eluent to afford TTF 7d (620 mg, 68%) as
mp¼65 ꢀC; 1H NMR (300 MHz, CDCl3)
d 2.43 (s, 6H, CH3), 2.66 (s,
12H, CH3), 7.15–7.35 (m, 10H, Ar), 17.1 (m, 2H, OH); 11B NMR
(96 MHz; CD3Cl)
H, 3.68. Found: C, 49.75; H, 3.55.
d
ꢁ0.58. Anal. Calcd for C32H28B2F4O4S6: C, 50.13;
4.3. Molecular structure
Single-crystal diffraction data were collected on APEXII, Bruker-
´
´
AXS diffractometer (Centre de diffractometrie X, Universite de

M. Guerro et al. / Tetrahedron 65 (2009) 6123–6127
6127
5. Zhu, Q.-Y.; Bian, G.-Q.; Zhang, Y.; Dai, J.; Zhang, D.-Q.; Lu, W. Inorg. Chim. Acta
2006, 359, 2303.
6. Zheng, P.; Guo, Y.-J.; Liu, W.; Li, Y.-Z.; Zuo, J.-L.; You, X.-Z. Transition Met. Chem.
2008, 33, 767.
7. Li, Y.-J.; Liu, W.; Li, Y.-Z.; Zuo, J.-L.; You, X.-Z. Inorg. Chem. Commun. 2008, 11, 1466.
8. Liu, W.; Xiong, J.; Wang, Y.; Zhou, X.-H.; Wang, R.; Zuo, J. L.; You, X.-Z. Organo-
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9. Ono, K.; Yamaguchi, H.; Taga, K.; Saito, K.; Nishida, J.-I.; Yamashita, Y. Org. Lett.
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10. Rhode, D.; Yan, C.-J.; Wan, L.-J. Langmuir 2006, 22, 4750.
11. (a) Bendikov, M.; Wudl, F.; Perepichka, D. F. Chem. Rev. 2004, 104, 4891; (b)
Fabre, J. M. Chem. Rev. 2004, 104, 5133; (c) Gorgues, A.; Hudhomme, P.; Salle´, M.
Chem. Rev. 2004, 104, 5151.
12. Guerro, M.; Pham, N. H.; Massue, J.; Bellec, N.; Lorcy. Tetrahedron 2008, 64, 5285.
13. Simonsen, K. B.; Becher, J. Synlett 1997, 1211.
14. Retting, S. J.; Trotter, J. Can. J. Chem. 1982, 60, 2957.
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Rennes, France). Crystal data and structure refinement parameters
for compound 3 (C9H9BF2O2S4): M¼326.21, Mo K radiation
a
(l
¼0.71073 Å), T¼100(2) K; monoclinic P21/a, a¼10.4729(14),
b¼10.0048(12), c¼13.6070(17) Å,
b
¼109.196(6)ꢀ, V¼1346.5(3) Å3,
Z¼4, d¼1.609 g cmꢁ3
,
m
¼0.716 mmꢁ1. The structure was solved by
direct methods using the SIR97 program,23 and then refined with
full-matrix least-square methods based on F2 (SHELX97)24 with the
aid of the WINGX program.25 All non-hydrogen atoms were refined
with anisotropic thermal parameters. H atoms were finally in-
cluded in their calculated positions, with starting position extracted
from maxima in difference electron density maps (HFIX 137). A
final refinement on F2 with 3040 unique intensities and 166 pa-
rameters converged at
served reflections with I>2
u
R(F2)¼0.0765 (R(F)¼0.032) for 2897 ob-
s
(I). The X-ray crystallographic data for
3 have been deposited, as supplementary publication number
CCDC 725800 at the Cambridge Crystallographic Data. Copies of the
data can be obtained free of charge from the CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK; e-mail: deposit@ccdc.cam.ac.uk.
18. Macedo, F.; Gwengo, C.; Lindeman, V.; Smith, M. D.; Gardinier, J. Eur. J. Inorg.
Chem. 2008, 3200.
19. Lau, J.; Simonsen, O.; Becher, J. Synthesis 1995, 521.
20. Domercq, B.; Grasso, C.; Maldonado, J.-L.; Halik, M.; Barlow, S.; Marder, S. R.;
Kippelen, B. J. Phys. Chem. B 2004, 108, 8647.
21. Bellec, N.; Boubekeur, K.; Carlier, R.; Hapiot, P.; Lorcy, D.; Tallec, A. J. Phys. Chem.
A 2000, 104, 9750.
References and notes
22. Chow, Y. L.; Johansson, C. I.; Zhang, Y.-H.; Gautron, R.; Yang, L.; Rassat, A.; Yang,
S.-Z. J. Phys. Org. Chem. 1996, 9, 7.
1. Special issue on ‘‘Molecular conductors’’ Batail, P. Ed. Chem. Rev. 2004, 104,
23. Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, G.; Giacovazzo, C.; Guagliardi,
A.; Moliterni, A. G. G.; Polidori, G.; Spagna, R. J. Appl. Crystallogr. 1999, 32, 115.
24. Sheldrick, G. M. SHELX97-Programs for Crystal Structure Analysis (Release 97-2);
Institu¨t fu¨ r Anorganische Chemie der Universita¨t: Tammanstrasse 4, D-3400
Go¨ttingen, Germany, 1998.
4887–5781.
´
2. Lorcy, D.; Bellec, N.; Fourmigue, M.; Avarvari, N. Coord. Chem. Rev. 2009, 253,
1398.
3. (a) Bellec, N.; Lorcy, D. Tetrahedron Lett. 2001, 42, 3189; (b) Massue, J.; Bellec, N.;
Chopin, S.; Levillain, E.; Roisnel, T.; Cle´rac, R.; Lorcy, D. Inorg. Chem. 2005, 44, 8740.
4. Bellec, N.; Massue, J.; Roisnel, T.; Lorcy, D. Inorg. Chem. Commun. 2007, 10, 1172.
25. Farrugia, L. J. J. Appl. Crystallogr. 1999, 32, 837.