SUPPLEMENTARY MATERIAL
Diferrocenyl oligothiophene wires: Raman and quantum
chemical study of valence-trapped cations
Sandra Rodríguez González,1 Juan Aragó,2 Pedro M. Viruela,2 Enrique Ortí,*2 Juan T.
López Navarrete,*1 Masa-aki Sato,3 and Juan Casado*1
[1]
S. Rodríguez González, Prof. Dr. J. T. López Navarrete, Dr. J. Casado
Department of Physical Chemistry, University of Málaga
29071 Málaga (Spain)
Fax: (+34) 952-132000
E-mail: casado@uma.es
[2]
J. Aragó, Prof. Dr. P. M. Viruela, Prof. Dr. E. Ortí
Instituto de Ciencia Molecular, Universidad de Valencia
46980 Valencia (Spain)
Fax: (+34) 963543274
E-mail: enrique.orti@uv.es
[3]
Prof. Masa-aki Sato
Graduate School of Maritime Science
Kobe University 5-1-1 Fukae-Minami, Higashinada, Kobe 658-0022,Japan.
lrc-r
lrc-l
drc
Figure S1. Relative position of the Cl3− counteranion in the delocalized (drc) and localized
(lrc-l and lrc-r) radical cations of 1●+.
Table S1. B3LYP/6-31G**-optimized bond lengths (Å) calculated for 1 in both neutral and
radical cation (drc, lrc-l and lrc-r) states.
Bond
C-C
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
S-S
18
19
20
21
22
23
24
25
neutral
drc
lrc-l
lrc-r
1.456
1.376
1.424
1.388
1.440
1.385
1.409
1.385
1.439
1.390
1.417
1.384
1.445
1.391
1.425
1.375
1.457
1.449
1.388
1.410
1.410
1.410
1.411
1.380
1.412
1.407
1.415
1.399
1.401
1.429
1.404
1.410
1.382
1.453
1.436
1.386
1.410
1.403
1.429
1.391
1.402
1.392
1.433
1.393
1.415
1.386
1.443
1.393
1.424
1.376
1.456
1.456
1.376
1.423
1.389
1.437
1.388
1.406
1.388
1.434
1.397
1.410
1.389
1.437
1.403
1.414
1.384
1.439
1.751
1.760
1.761
1.761
1.756
1.759
1.764
1.748
1.743
1.762
1.765
1.768
1.760
1.755
1.767
1.743
1.755
1.755
1.763
1.758
1.756
1.756
1.764
1.764
1.750
1.760
1.759
1.763
1.751
1.761
1.763
1.751
Table S2. B3LYP/6-31G**-optimized bond lengths (Å) calculated for 2 in both neutral and
radical cation (drc, lrc-l and lrc-r) states.
Bond
C-C
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
S-S
18
19
20
21
22
23
24
25
neutral
drc
lrc-l
lrc-r
1.457
1.376
1.424
1.388
1.440
1.384
1.409
1.386
1.446
1.393
1.420
1.382
1.439
1.388
1.424
1.376
1.457
1.448
1.386
1.410
1.410
1.412
1.409
1.384
1.412
1.413
1.421
1.395
1.405
1.414
1.408
1.412
1.384
1.449
1.438
1.386
1.412
1.401
1.432
1.389
1.403
1.393
1.440
1.397
1.417
1.385
1.436
1.391
1.423
1.377
1.456
1.456
1.377
1.423
1.390
1.437
1.388
1.408
1.388
1.443
1.399
1.414
1.386
1.432
1.401
1.412
1.385
1.439
1.751
1.759
1.759
1.763
1.762
1.753
1.759
1.751
1.750
1.763
1.762
1.769
1.770
1.752
1.763
1.752
1.755
1.753
1.763
1.763
1.767
1.755
1.761
1.752
1.752
1.761
1.760
1.767
1.762
1.756
1.752
1.754
Table S3. B3LYP/6-31G**-optimized bond lengths (Å) calculated for 3 in both neutral and
radical cation (drc) states.
Bond
C-C
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
S-S
18
19
20
21
22
23
24
25
neutral
drc
1.502
1.371
1.421
1.379
1.445
1.380
1.415
1.381
1.442
1.381
1.415
1.380
1.445
1.378
1.423
1.370
1.498
1.495
1.385
1.404
1.395
1.420
1.407
1.387
1.407
1.410
1.407
1.387
1.407
1.420
1.395
1.405
1.385
1.495
1.747
1.757
1.758
1.759
1.759
1.758
1.761
1.750
1.739
1.763
1.755
1.762
1.762
1.755
1.763
1.739
1●+
2●+
lrc-l
drc
lrc-r
lrc-l
drc
lrc-r
3●+
drc
Figure S2. The unpaired-electron spin density distributions (contour: 0.004 e bohr–3) for
radical cations 1●+, 2●+ and 3●+.
Figure S3. UB3LYP/6-31G** Raman spectra of lrc-l and drc structures for 1●+.
Scheme S1. Effect on the planarization of the thienyl backbone of the metoxyhexyl
substitution . Realize that the mesomeric effect of the methoxy group towards the cation is
only effective for 1●+ what imparts a modulation of the molecular and electronic properties.
Synthesis and characterization of compound 2.
General Information. 1H-NMR experiments were performed using HITACHI R-1500
(60MHz) and VARIAN UNITY500 (500MHz) spectrometers in the pulse Fourier
transform mode. Infrared spectra were obtained using a JASCO FT-IR-230 spectrometer.
Materials. 3-Hexyl-2,2’-bithiophene, and 2-iodo-3-methoxythiophen, ferrocenylzinc
chloride were synthesized according to previously reported methods.1,2,3 Ether and
tetrahydrofuran (THF) were distilled under nitrogen over LiAlH4 and CaH2, respectively.
N-methylpyrrolidone (NMP) was dried over type 4A molecular sieves and distilled under
reduced pressure. Unless stated otherwise, all reagents were purchased from commercial
sources and used without purification.
Scheme S2. Synthesis of quaterthiophene derivative 2.
5,5’-Bis(tri-n-butylstannyl)-3-hexyl-2,2’-bithiophene (I). 3-Hexyl-2,2’-bithiophene (1.30
g, 5.20 mmol) was dissolved in ether (8 mL) under nitrogen. To the solution was added nbutyllithium (7.20 mL, 11.5 mmol, 1.6 M in hexane) dropwise for 20 min at 0 °C. After
stirring for 30 min at room temperature, tri(n-butyl)tin chloride (3.00 ml, 10.9 mmol) was
added for 10 min, and then the solution was stirred overnight. The resulting red solution
was poured into water and extracted with ether. The organic layer was washed with a sat.
CuSO4 aqueous solution and dried with MgSO4. The solvent was removed by rotary
evaporation and the crude product was flash chromatographed on alumina (hexane) to give
I (1.74 g, 40.0%) as a colorless viscous oil.
1
H NMR(60MHz,CDCl3):δ(ppm) 7.19 (d, J=3.52Hz, 1H), 7.11(d, J=3.52Hz, 1H), 6.93 (s, 1H),
2.79(t, J=7.62Hz, 2H), 1.63~0.80 (m, 65H).
3,3”’-Dimethoxy-3’-hexyl- 2,2’:5’,2” :5”,2”’-quaterthiophene (II). A flask was charged
with I (1.05 g, 1.26 mmol), 2-iodo-3-methoxylthiophene (0.66 g, 2.75 mmol),
tetrakis(triphenylphosphine)palladium(0) (0.32 g, 0.28 mmol), and NMP (30 mL). After
being purged with argon gas, the mixture was heated to 90 °C and stirred overnight. The
red reaction mixture was allowed to cool to room temperature, treated with brine, and
extracted with benzene. The organic layer was dried over MgSO4. After the solvent was
removed by rotary evaporation, the crude product was flash chromatographed on silica gel
(benzene/hexane) to give II (0.484 g, 81.0 %) as a red viscous oil.
1
H NMR(400MHz,CDCl3):δ(ppm) 7.16 (d, J=3.78Hz, 1H), 7.05 (d, J=5.36Hz, 1H), 7.04 (m, 2H),
7.02 (d, J=3.78Hz, 1H), 6.87 (m, 1H), 6.85 (d, J=5.36Hz, 1H), 3.95 (s, 6H), 2.76 (t, J=7.88Hz, 2H),
1.69~1.63 (m, 2H), 1.43~1.28 (m, 6H), 0.89 (t, J=5.99Hz, 3H).
5,5”’-Diferrocenyl-3’-hexyl-3’,3”’-dimethoxy-2,2’:5’,2”:5”,2”’-quaterthiophene
(2).
To a solution of II (0.45 g, 0.95 mmol) in THF (25 mL) at −78 °C was added dropwise nbutyllithium (2.4 mL, 3.8 mmol, 1.6 M in hexane) for 10 min under argon. The reaction
mixture was stirred at 0 °C for 0.5 h before being cooled back to −78 °C. To that solution,
iodine (0.97 g, 3.8 mmol) in THF (5.0 mL) was added and stirred at room temperature for 2
h. The mixture and dichloro- bis(triphenylphosphine)palladium(2) (0.35 g, 0.50 mmol) was
added to a solution of ferrocenylzinc chloride (prepared from ferrocene (1.77 g, 9.50
mmol), t-butyllithium (5.88 mL, 10.0 mmol, 1.7 M in pentane), and zinc chloride (1.36 g,
10.0 mmol) in THF (40 mL)) 0 °C. The resulting black mixture was gradually warmed to
room temperature and then refluxed for 12 h, before being poured into 2 M HCl. The
aqueous layer was extracted with benzene. The organic extract was washed with a sat.
Na2S2O3 aqueous solution and brine and dried over MgSO4. The solvent was removed by
rotary evaporation. The residue was treated with flash chromatography on silica gel
(benzene/hexane) and recrystallized from a mixture of benzene/hexane to provide 0.140 g
(17.5%) of 2 as red crystals.
Mp 197-199°C; 1H NMR(400MHz,CDCl3):δ(ppm) 7.13 (d, J=3.78Hz, 1H), 7.04 (d, J=3.79Hz,
1H), 7.01 (s, 1H), 6.79 (s, 1H), 6.78 (s, 1H), 4.57 (m, 4H), 4.32 (m, 4H), 4.14 (s, 10H), 3.99 (s, 3H),
3.98 (s, 3H), 2.79(t, J=7.88Hz, 2H), 1.73~1.67 (m, 2H), 1.45~1.33 (m, 6H), 0.91 (t, J=6.94 Hz,
3H).; IR (KBr) 3080, 2951, 2925, 2825, 1568, 1520, 1458, 1381, 1221, 1092, 814cm-1 ; MS m/z
842 (M+).
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H.Masauda, K.Kaeriyama, H.Suezawa, M.Hirota, J. Polym. Sci., A, 30, 945 (1992)
(2)
L.L.Miller, Y.Yu, J.Org.Chem., 60, 6813 (1995)
(3)
M.Iyoda, T.Kondo,T.Okabe, H.Matsuyama, S.Sasaki, Y.Kuwatani, Chem. Lett. 35
(1997)
NMR of 2 in CDCl3
4.13
1H
1.0
0.9
0.00
0.8
4.04
0.7
0.6
0.91
1.34
1.54 1.35
1.68
1.42
0.2
7.36
7.26
7.11
0.3
2.77
6.89
6.83
0.4
4.30
4.56
0.5
0.1
0.0
0.80 3.34 1.95
7.5
7.0
IR of 2 (KBr)
3.49
6.5
6.0
5.5
5.0
4.5
8.21
4.0
3.65
3.5
3.0
3.64 11.66
2.5
2.0
1.5
5.76
1.0
0.5
0.0