Supporting Information
Synthesis of soluble ferrocene-based polythiophenes and their properties
Contents
Synthesis of ferrocenecarbonyl chloride ........................................................................ S1
Synthesis of 2-(thiophen-3-yl) ethyl ferrocenoate (TEF) ............................................... S3
Synthesis of 2-(thiophen-3-yl) methyl ferrocenoate (TMF) ........................................... S3
Polymerization of 3-ethanolthiophene (3ET) ................................................................. S4
Polymerization of TEF ................................................................................................... S6
Polymerization of TMF .................................................................................................. S7
Polymerization of 3-hexylthiophene (3HT) ................................................................... S8
Copolymerization of 3TE and 3HT ................................................................................ S9
Copolymerization of TEF and 3HT .............................................................................. S10
Copolymerization of TMF and 3HT ............................................................................. S11
Synthesis of ferrocenecarbonyl chloride
The ferrocenecarbonyl chloride was synthesized by using two different chlorinating agents
as shown in Scheme S1. The details are given as follow.
First method
In the first method oxylyl chloride was used as chlorinating agent [1]. In a typical
procedure vacuum dried 10 g (43.47 mmol) ferrocenecarboxylic acid, 150 ml freshly dried
dichloro methane (DCM), and 100 drops of pyridine (dried over molecular sieves) were
added to pre-baked three necked flask. Then 12.5 ml (143 mmol) oxylyl chloride was
added to the reaction mixture slowly. The reaction mixture was refluxed for 16 hours
under argon atmosphere and then extra oxylyl chloride and solvent were evaporated under
vacuum. Then petroleum ether (dried over A4 molecular sieves) was added to the crude
mixture and refluxed for half an hour. Petroleum ether with dissolved product was filtered
S1
using cannula into another pre-weighed and pre-backed round bottom flask. Petroleum
ether was evaporated and product was weighed (55.5% yield) and kept under positive
pressure of dry argon until used for next reaction.
Scheme S1: Schematic illustration of synthesis of TEF and TMF.
Second method
The second method was executed using thionyl chloride as chlorinating agent, DCM as
solvent, and TEA as catalyst [2]. In the typical procedure a pre-baked three necked round
bottomed flask was filled with 6.90 g (30mmol) ferrocenecarboxylic acid, and 2.6 ml (35
mmol) thionyl chloride mixed with 18.5 ml freshly dried DCM under argon atmosphere.
Whole mixture was stirred for 10 minutes. In another round bottom flask, after purging
with nitrogen, 8.3 ml TEA and 10 ml DCM (freshly dried) were mixed. The mixture of
TEA and DCM was added to the previously prepared mixture in three necked flask very
slowly drop by drop with vigorous stirring. The whole reaction mixture was stirred at 0°C
for 2 hours and for half an hour at room temperature. Extra solvent and thionyl chloride
was evaporated under vacuum. Then diethyl ether was added to the crude mixture and
refluxed for half an hour. Diethyl ether with dissolved product was filtered using cannula
into a round bottom flask. Diethyl ether was evaporated leaving behind pure product. As
the product was highly reactive and sensitive to moisture, so it was used immediately for
next reaction or otherwise kept in argon atmosphere.
S2
Synthesis of 2-(thiophen-3-yl) ethyl ferrocenoate (TEF)
Ferrocene carbonyl chloride (4.528g, 18.22mmol) and 3-thiopheneethanol (3TE) (2.3454
g, 18.22mmol) were dissolved in freshly dried DCM (20 ml) under argon atmosphere in a
pre-baked round bottom flask. Then pyridine (1.62 ml, 20.12mmol) was added under
stirring. The whole system was refluxed for 30 hours at 40°C and then the reaction
mixture was quenched with deionized water (15 ml) followed by washing with 5% sod.
carbonate solution (30 ml x 2), and finally washed with water (20 ml x 2). The organic
layer was dried with MgSO4 (anhydrous) over night, filtered and solvent was evaporated.
The product was further dried in vacuum oven at 40°C [3].
Table S1: Details of the synthesis of TEF.
Ferrocene carbonyl
3-thiopheneethanol Mole Time Temperature
chloride (A)
(B)
ratio
°C
g
mmol
mol/L
g
mmol mol/L A:B hours
4.528
18.22
1.08
2.3454 18.22 1.129 1:1
30
40
Synthesis of 2-(thiophen-3-yl) methyl ferrocenoate (TMF)
Ferrocene carbonyl chloride (5.8577g, 23.57 mmol) and 3-thiophene methanol (2.2970 g,
20.12mmol) were dissolved in freshly dried DCM (20 ml) under argon atmosphere. Then
pyridine (1.62 ml, 20.12mmol) was added during stirring. The whole system was refluxed
for 30 hours at 40°C and the resulting reaction mixture was quenched with deionized
water (15 ml) followed by washing with 5% sod. carbonate solution (30 ml x 2) and water
(20 ml x 2). The organic layer was dried with MgSO4 over night. Solvent was evaporated,
and the product was dried in vacuum oven at 40°C [3].
S3
Figure S1: 1H-NMR spectrum of TEF.
Table S 2: Details of the synthesis of TMF.
Ferrocene carbonyl
3-Thiophenemethanol Mole Time Temperature
chloride (A)
(B)
ratio
°C
g
mmol
mol/L
g
mmol mol/L A:B hours
5.8577 23.57
1.17
2.297
20.12 1.129
1:1
30
40
Polymerization of 3-ethanolthiophene (3ET)
All the polymerization reactions were carried out at room temperature (25°C). 3ET was
polymerized according to the reported procedure [4, 5] with little modifications. In a
reaction flask, anhydrous FeCl3 (3.244 g, 20 mmol) was taken and dried under vacuum at
100 °C. After drying 150 ml of dried CHCl3 was added and the mixture was stirred for 10
minutes under argon atmosphere. Then a solution of 3ET (0.64095 g, 5 mmol) in 50 ml
CHCl3 was slowly added to the mixture of FeCl3 and CHCl3. The resulting whole mixture
was stirred for 8 hours, concentrated, precipitated in methanol, and filtered. The residues
were added to CHCl3 and refluxed with ammonia solution for one hour. The organic layer
was separated and washed with ammonia solution and 0.5 M EDTA solution. Finally the
organic layer was washed with distilled water. The solvent was evaporated and product
was dried under vacuum.
S4
Figure S2: 1H-NMR spectrum of TMF.
Scheme S2: Polymerization of 3ET, TEF, TMF, and 3HT.
S5
Polymerization of TEF
TEF was polymerized according to the reported procedure [4, 5] with little modifications.
FeCl3 (0.9504 g, 5.8 mmol) was taken in reaction flask and dried under vacuum at 100 °C.
After cooling down in argon atmosphere 60 ml of dried CHCl3 was added. The mixture
was stirred for 10 minutes and then TEF (1.000 g, 2.930 mmol) (dissolved in 30 ml of
dried CHCl3) was added slowly. The whole mixture was stirred for 8 hours, concentrated,
precipitated in methanol, and filtered. The residues were added to CHCl3 and resulting
mixture was refluxed with ammonia solution for one hour. The organic layer was
separated and washed with ammonia solution and 0.5 M EDTA solution. Finally the
organic layer was washed with distilled water. The solvent was evaporated and product
was dried under vacuum.
Table S3: Reaction conditions of polymerization of 3ET.
3ET (A)
g
mmol mol/L
0.6409
5
0.025
FeCl3 Anhydrous (B)
g
mmol mol/L
3.244
20
0.1
Mole ratio Time Temperature
A:B
hours
°C
1:4
8
25
Figure S3: 1H-NMR spectrum of P3ET.
S6
Table S4: Reaction conditions of polymerization of TEF.
TEF (A)
g
mmol mol/L
1.0000 2.93
0.05
FeCl3 Anhydrous (B)
g
mmol mol/L
0.9504
5.8
0.2
Mole ratio Time Temperature
A:B
hours
°C
1:4
8
25
Figure S4: 1H-NMR spectrum of PTEF.
Table S5: Reaction conditions for polymerization of TMF.
TMF (A)
g
mmol mol/L
1.0000 3.06
0.05
FeCl3 Anhydrous (B)
G
mmol mol/L
0.9945 6.13
0.2
Mole ratio Time Temperature
A:B
hours
°C
1:4
8
25
Polymerization of TMF
TMF was polymerized in the same way as TEF [4, 5]. FeCl3 (0.9945 g, 6.13 mmol) was
taken in reaction flask and dried under vacuum at 100 °C for 1 hour. After cooling down
in argon atmosphere 60 ml of dried CHCl3 was added. Then the TMF (1.000 g, 3.06
mmol) (dissolved in 30 ml of dried CHCl3) was added and the whole mixture was stirred
for 8 hours. The reaction mixture was concentrated, precipitated in methanol, and filtered.
The residues were added to CHCl3 and resultant mixture was refluxed with ammonia
solution for one hour. The organic layer was separated and washed with ammonia solution
S7
and 0.5 M EDTA solution. Finally the organic layer was washed with distilled water. The
solvent was evaporated and product was dried under vacuum.
Figure S5: 1H-NMR spectrum of PTMF.
Polymerization of 3-hexylthiophene (3HT)
3-Hexylthiophene (3HT) was polymerized by following the typical procedure [4, 5]. FeCl3
(6.4880G, 40 mmol) was taken in pre-baked reaction flask, purged with Ar gas and dried
under vacuum at 100°C with continuous stirring. Then 400 ml CHCl3 was added and
stirred for five minutes to make good suspension. Then 3HT (1.683 g, 10 mmol),
dissolved in 30 ml of dried CHCl3, was added and the whole mixture was stirred for 8
hours at room temperature. The mixture was concentrated and precipitated in methanol.
Precipitates were dissolved again in to the CHCl3 and resulting solution was refluxed with
ammonia solution for one hour. The organic layer was separated and washed with
ammonia solution and 0.5 M EDTA solution. Finally the organic layer was washed with
distilled water. The organic layer was filtered to remove the insoluble particles. The
solvent was evaporated and the product was dried in vacuum oven.
Table S6: Reaction conditions for polymerization of 3HT.
3HT (A)
g
mmol mol/L
1.683
10
0.025
FeCl3 Anhydrous (B)
g
mmol mol/L
6.4880
40
0.1
S8
Mole ratio Time Temperature
A:B
hours
°C
1:4
8
25
Figure S6: 1H-NMR spectrum of P3HT.
Copolymerization of 3TE and 3HT
3-Thiopheneethanol was copolymerized with the 3HT [4, 5]. In a typical procedure
anhydrous FeCl3 (6.4880 g, 40 mmol) was taken in pre-baked reaction flask and dried
under vacuum at 100 °C. After cooling down under argon atmosphere 300 ml of dried
CHCl3 was added. The mixture was stirred for 10 minutes. In another flask 3TE and 3HT
(10 mmol each) dissolved in CHCl3 (100 ml) and resulting solution was added slowly to
the FeCl3 and CHCl3 mixture. Then the resulting whole mixture was stirred for 8 hours.
The reaction mixture was concentrated, precipitated in methanol, and filtered. The
residues were added to CHCl3 and resulting mixture was refluxed with ammonia solution
for one hour. The organic layer was separated and washed with ammonia solution and 0.5
M EDTA solution. Finally the organic layer was washed with distilled water. The
dissolved product was filtered to remove the insoluble part. The solvent was evaporated to
concentrate the product and re-precipitated in methanol 2 times. The product was dried
under vacuum.
Table S7: Reaction condition for the copolymerization of 3TE with 3HT.
3TE (A)
g
1.2819
mmol
3.06
3HT (B)
mol/L
g mmol mol/L
0.025 1.683 10 0.25
FeCl3 Anhydrous (C)
g
6.488
S9
mmol
40
mol/L
0.1
Mole ratio
Time
T
A:B:C
1:1:4
hours
8
°C
25
Figure S7: 1H-NMR spectrum of poly (3TE-co-3HT).
Copolymerization of TEF and 3HT
TEF was also copolymerized with the 3HT [4]. In a typical procedure anhydrous FeCl3
(3.8084 g, 23.84 mmol) was taken in reaction flask and dried under vacuum at 100 °C
after cooling down in argon atmosphere 125 ml of dried CHCl3 was added. The mixture
was stirred for 10 minutes. In another flask TEF and 3HT (5.87 mmol each) were
dissolved in 125 ml of dried CHCl3 and resulting solution was slowly added to the FeCl3
and CHCl3 mixture. The whole mixture was stirred for 8 hours. The reaction mixture was
concentrated, precipitated in methanol, and filtered. The residues were added to CHCl3
and resulting mixture was refluxed with ammonia solution for one hour. The organic layer
was separated and washed again with ammonia solution and 0.5 M EDTA solution.
Finally the organic layer was washed with distilled water. The dissolved product was
filtered to remove the insoluble part. The solvent was evaporated to concentrate the
product and re-precipitated in methanol 2 times. The product was dried under vacuum.
Table S8: Reaction conditions for the copolymerization of TEF with 3HT.
TEF (A)
g
2
mmol
5.87
mol/L
0.025
3HT (B)
g
mmol mol/L
0.9879 5.87 0.25
FeCl3 Anhydrous (C)
g
3.8084
S10
mmol
23.84
mol/L
0.1
Mole ratio
Time
T
A:B:C
1:1:4
hours
8
°C
25
Copolymerization of TMF and 3HT
TMF was copolymerized with the 3HT in the same way as the TEF was [4]. In a typical
procedure anhydrous FeCl3 (1.9853 g, 12.24 mmol) was taken in reaction flask and dried
under vacuum at 100 °C. After cooling down in argon atmosphere 64 ml of dried CHCl3
was added. The mixture was stirred for 10 minutes. In another flask TMF and 3HT (3.06
mmol each) were dissolved in 60 ml of dried CHCl3 and the resulting solution was slowly
added to the FeCl3 and CHCl3 mixture. The whole mixture was stirred for 8 hours. The
reaction mixture was concentrated, precipitated in methanol, and filtered. The residues
were added to CHCl3 and resulting mixture was refluxed with ammonia solution for one
hour. The organic layer was separated and washed with ammonia solution and 0.5 M
EDTA solution. Finally the organic layer was washed with distilled water. Dissolved
product was filtered to remove the insoluble part. The solvent was evaporated to
concentrate the product and re-precipitated in methanol 2 times. The product was dried
under vacuum.
Table S9: Reaction conditions forcopolymerization of TMF with 3HT.
TMF (A)
g
1
mmol
3.06
3HT (B)
mol/L
0.025
g mmol mol/L
0.5149 3.06 0.025
FeCl3 Anhydrous (C)
g
1.9853
mmol
12.24
mol/L
0.1
Mole
ratio
A:B:C
1:1:4
Figure S 8: 1H-NMR spectrum of poly (TMF-co-3HT).
S11
Time
T
hours
6
°C
25
Figure S9: Possible ways of electron transfer between electrode and a) 3HT, b) TEF,
and c) poly (TEF-co-3HT) respectively.
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S12