Supporting Information for the paper
Metal-free phthalocyanines bearing eight alkylsulfonyl substituents: design, synthesis, electronic structure and mesomorphism of new electron-deficient mesogens
Benoît Tylleman,a Gabin Gbabode,a Claire Amato,a Claudine Buess-Herman,b Vincent Lemaur,c Jérôme Cornil,c Rafael Gómez Aspe,d Yves Henri Geerts,*a and Sergey Sergeyev*a
a) Laboratory of Polymer Chemistry, Faculté des Sciences, Université Libre de Bruxelles (ULB),
CP
206/1,
Boulevard
du
Triomphe,
1050
Bruxelles,
Belgium;
e-mail
[email protected];
[email protected] b) Laboratory of Analytical and Interface Chemistry, Faculté des Sciences, Université Libre de Bruxelles (ULB), CP 255, Boulevard du Triomphe, 1050 Bruxelles, Belgium c) Laboratory for Chemistry of Novel Materials, University of Mons-Hainaut, Place du Parc 20, 7000 Mons, Belgium d) Department of Organic Chemistry, Universidad Complutense de Madrid, Avda. Complutense, 28040 Madrid, Spain
Description of Supporting Information 1. Synthesis of thiols 4b,c: experimental procedures and analytical data 2. Synthesis of dinitrile 2a: experimental procedures and analytical data 3. Computational details 4. Electrochemical data 5. Additional powder XRD data: 5.1. Indexing of reflections for LC mesophases of 1a,c and 6b 5.2. High angle region (π-stacking distance) of the XRD patterns of 1a measured at room temperature before and after isotropisation. 5.3. XRD patterns of Colo, Colr1 and Colr2 phases of 1c. 6. MALDI-MS data for the attempted synthesis of 1a from 2a:
SI1
Synthesis of thiols 4b,c.
(±)-1-Bromo-2-butyloctane. A solution of CBr4 (11.55 g, 34.85 mmol) and (±)-2-butyloctan1-ol (6.0 mL, 26.8 mmol) in CH2Cl2 (55.0 mL) was added dropwise at 0 °C to the solution of PPh3 (9.84 g, 37.5 mmol) in CH2Cl2 (15 mL). The mixture was stirred for 45 min, then poured into hexane/Et2O (4 : 1 v/v, 100 mL) and the resulting precipitate (Ph3PO) was filtered and discarded. The filtrate was passed through a plug of SiO2 and evaporated to afford 5.08 g (76%) of (±)-1-bromo-2-butyloctane, which was judged > 95% by 1H NMR and was used without further purification. Colorless liquid; Rf (hexane): 0.97; IR (KBr): ν (cm–1) = 2958s, 2927s, 2856s, 1466m, 1379m, 1254m, 1119w, 723m, 669m, 652m; δH (300 MHz, CDCl3, Me4Si, 25 °C) 3.44 (2 H, d, J 4.7 Hz, CH2–Br), 1.53–1.64 (1 H, m, CHCH2Br), 1.16–1.45 (16 H, m), 0.83–0.94 (6 H, m, CH3); δC (75 MHz, CDCl3, Me4Si, 25 °C) 39.5 (CH2Br), 32.6, 32.3, 31.8, 31.6, 29.5, 28.8, 26.5, 22.8, 22.6, 14.1 (CH3), 14.0 (CH3); m/z (EI) 247 ([M–H]+). (±)-1-Bromo-2-hexyldecane. Prepared similarly to (±)-1-bromo-2-butyloctane starting from (±)-2-hexyldecan-1-ol. Colorless liquid; yield 95%; Rf (hexane): 1.00; δH (300 MHz, CDCl3, Me4Si, 25 °C) 3.44 (2 H, d, J 4.8 Hz, CH2–Br), 1.52–1.65 (1 H, m, CHCH2Br), 1.15–1.43 (24 H, m), 0.81–0.93 (6 H, m, CH3); δC (75 MHz, CDCl3, Me4Si, 25 °C) 39.7 (CH2Br), 39.5, 32.6, 31.9, 31.8, 31.6, 29.8, 29.5, 29.4, 29.2, 26.6, 26.5, 22.7, 22.6, 14.10 (CH3), 14.08 (CH3). (±)-2-Butyl-1-octanethiol (4b). Thiourea (4.57 g, 60.0 mmol) was dissolved in ethanol (50.0 mL) upon reflux. To the resulting solution, (±)-1-bromo-2-butyloctane (3.25 g, 13.0 mmol) was added dropwise, the mixture was stirred for 5 h, and then allowed to reach room temperature. Ethanol was evaporated, NaOH solution (94.0 mL, 20% in H2O) was added to the residue, and the mixture was heated to reflux for 3 h in Ar. After cooling to room temperature, the mixture was neutralized with HCl (10% in H2O) until pH 7 and extracted SI2
with CH2Cl2 (3 × 50 mL). Combined organic layers were dried over MgSO4 and evaporated. Column chromatography (SiO2, hexane) gave 4b (1.00 g, 38%) as a colorless liquid; Rf (hexane): 0.69; IR (KBr) : ν (cm–1) = 2956s, 2926s, 2856s, 2731w, 2696w, 2580w, 1466m, 1379m, 1265w, 725m; δH (300 MHz, CDCl3, Me4Si, 25 °C) 2.53 (2 H, dd, J1 5.4 Hz, J2 8.1 Hz, CH2–SH), 1.18–1.55 (17 H, m), 1.15 (1 H, t, J 8.1 Hz, SH), 0.84–0.93 (6 H, m, CH3); δC (75 MHz, CDCl3, Me4Si, 25 °C) 40.1 (CH2SH), 32.4, 32.1, 32.0, 29.7, 28.9, 28.6, 26.6, 23.0, 22.7, 14.1 (2 CH3). (±)-2-Hexyl-1-decanethiol (4c). Prepared similarly to 4b starting from (±)-1-bromo-2hexyldecane. Yield 33%; colorless liquid; δH (300 MHz, CDCl3, Me4Si, 25 °C) 2.53 (2 H, dd, J1 5.4 Hz, J2 8.1 Hz, CH2–SH), 1.19–1.55 (25 H, m), 1.17 (1 H, t, J 8.2 Hz, SH), 0.81–0.92 (6 H, m, CH3); δC (75 MHz, CDCl3, Me4Si, 25 °C) 40.1 (CH2SH), 32.3, 32.1, 31.9, 31.8, 29.9, 29.6, 29.3, 28.6, 26.61, 26.58, 22.7, 14.1 (2 CH3). Synthesis of 4,5-bis(dodecylsulfonyl)phthalonitrile (2a). H2O2 (15 mL, 35% in H2O) was added to the solution of dinitrile 5a (3.24 mmol, 1.71 g) in AcOH (20 mL). The mixture was heated to reflux for 3 h, allowed to reach r.t. and poured in H2O (200 mL). The precipitated white solid was collected by filtration, extensively washed with H2O and dried in vacuum to give 2a (1.61 g, 84%). Colorless solid. Rf (CH2Cl2): 0.66 ; mp 84–86 °C ; IR (KBr): ν (cm–1) = 3103w, 2960m, 2920s, 2870m, 2850s, 2235w (C≡N), 1470m, 1344m, 1315s, 1271m, 1155s, 1124m, 941w, 924w, 721w, 667m; δH (300 MHz, in CDCl3, Me4Si, 25 °C) 8.68 (s, 2H, CHarom), 3.62–3.69 (m, 4H, CH2SO2), 1.68–1.80 (m, 4H, CH2CH2SO2), 1.17–1.47 (m, 36H), 0.88 (t, J = 6,6 Hz, 6H, CH3); δC (75 MHz, in CDCl3, Me4Si, 25 °C) 144.4 (CSO2), 137.5 (CHarom), 121.1 (CN), 113.1 (CCN), 57.1 (CH2SO2), 31.9 (CH2CH2SO2), 29.6 (CH2), 29.5 (CH2), 29.4 (CH2), 29.3 (CH2), 29.2 (CH2), 28.9 (CH2), 28.2 (CH2), 22.7 (CH2), 22.3 (CH2CH3), 14.1 (CH3); m/z (HR-EI): calc. 592.3368 (C32H52N2O4S2), found 592.3486 (M+).
SI3
Computational data In order to elucidate the preferential orientation of the alkyl chains in the molecule of Pc(SO2R)8,
we
first
optimized
the
geometry
of
a
model
molecule,
1,2-
di(methylsulfonyl)benzene, at the Density Functional Theory (DFT) level using the B3LYP functional and a 6-31G* basis set. The long alkyl chains of Pc(SO2R)8 were replaced by methyl groups to reduce the computational time. The calculations show that the conformation where the alkyl chains are pointing in opposite directions (the torsion angles between the methyl group and the phenyl ring is estimated to be 77°) is more stable by 39 kJ mol–1 compared to the conformation in which they are pointing in the same direction. This orientation contrasts with the preferred geometry previously obtained for alkoxycarbonyl substituents at the same level of theory.26 This difference originates from the tetrahedral geometry of the sulfur atom in the SO2 group compared to the planar geometry of an sp2carbon in the ester function. The geometry of octasulfone Pc(SO2Me)8 was next optimized at the same level of theory starting from the stable conformation of a model molecule, 1,2di(methylsulfonyl)benzene.
Figure SI1. The most stable conformation of 1,2-di(methylsulfonyl)benzene, as a model for one dialkylsulfonyl-substituted benzene ring of the phthalocyanine macrocycle.
SI4
Table SI1. Reduction (Eired) and oxidation (Eiox) potentials for 0.5 mM of Pc(SR)8 (= 9a), Pc(SO2R)8 (= 1a) and Pc(COOR)8 (R = C12H25 in all cases) in CH2Cl2 containing 0.1 M nBu4NPF6, at different scan rates. Ei = (Epci + Epai)/2. Pc(CO2R)8 Scan rate,
Pc(SR)8
Pc(SO2R)8
20
50
100
200
20
50
100
200
20
50
100
200
E1red
–0.43
–0.45
–0.47
–0.43
–0.87
- 0.88
–0.89
–0.89
–0.13
–0.14
–0.15
–0.11
E2red
–0.72
–0.74
–0.76
–0.71
–1.09
- 1.08
–1.08
–1.09
–0.52
–0.53
–0.53
–0.53
E3red
–1.45
–1.47
–1.48
–1.45
–1.80
- 1.78
–1.77
–1.78
–1.12
–1.12
–1.12
–1.12
E4red
–1.71
–1.72
–1.70
–1.72
–1.38
–1.38
–1.38
–1.37
E1ox
1.13
1.13
1.13
1.16
0.44
0.46
0.46
0.46
1.48
1.47
1.48
1.48
E2ox
1.61
1.60
1.58
1.60
0.97
0.96
0.95
0.95
1.86
1.85
1.90
1.35
1.33
1.34
1.36
1.57
1.60
1.60
1.61
–1
mV s
E3ox E4ox
SI5
Table SI2. X-ray data for the mesophases of 6b. Compound
Phase
h
k
6b
Colh (23°C)
1 1 2 2 2
0 1 0 1 3
a
l
dobs (Å)
dcalc (Å)
22.6 13.2 11.4 8.6 5.3 4.6 a
22.7 13.1 11.4 8.6 5.2
dobs (Å)
dcalc (Å)
Lattice parameters a= 26.3 Å S= 597 Å2
Halo of the liquid-like alkyl chains.
Table SI3. X-ray data for the mesophases of 1a. Compound
Phase
h
k
1a
Colr0 (-70°C)
0 2
1 0
34.2 20.6
34.2 20.6
Colr1 (-48°C)
0 2 2
1 0 1
34.6 20.8 17.6
34.6 20.8 17.8
a= 41.6 Å b= 34.6 Å S= 1439 Å2 P2mm
Colr2 (25°C)
0 2 1 5 2
1 1 4 1 4
35.6 19.0 8.5
35.6 19.0 8.7 8.7 8.3
a= 45.0 Å b= 35.6 Å S= 1600 Å2 P2mm
1 2 2 2 3 3
1 0 1 2 1 3
27.4 21.8 18.5 13.7 13.4 9.1
a= 43.6 Å b= 35.3 Å S= 1538 Å2 P2gg
Colr3 (85°C)
l
4.8 a 27.4 21.8 18.7 13.6
Lattice parameters a= 41.2 Å b= 34.2 Å S= 1409 Å2 P2mm
9.0 4.9 a a Halo of the liquid-like alkyl chains (The positions of this halo could not be estimated for Colr0 and Colr1 due to the presence of rather more intense diffraction peaks of ice in this region).
SI6
Table SI4. X-ray data for the mesophases of 1c. Compound
Phase
h
k
1c
Colo (120°C a)
2 0 1 3 4 5 4 6 5 0 3 6 6
0 1
Colr1 (30°C)
Colr2 (135°C)
1 0 1 0
l
dobs (Å)
dcalc (Å)
28.7 26.8 24.9 15.2 14.4 10.4 10.1 9.6 9.0
28.9 26.8 24.8 15.3 14.4 10.4 10.1 9.6 9.0 8.9 8.3 8.0 7.6
3
2
1 2 3 2 4 0 1 2
1 0 1 2 2 4 4 4
1 2 3 2
1 0 1 2
8.3 8.1 7.6 4.9 b 27.6 23.5 14.1 13.9 9.7 8.5 8.0 4.9 b
27.0 23.6 14.3 13.6 4.9 b a First heating only. b Halo of the liquid-like alkyl chains.
Lattice parameters a= 57.8 Å b= 26.9 Å γ= 93.1° S= 1550 Å2 P1
27.6 23.5 14.2 13.8 9.7 8.5 8.4 8.0
a= 46.9 Å b= 34.1 Å S= 1598 Å2 P2gg/C2mm
27.0 23.6 14.2 13.5
a= 47.1 Å b= 33.0 Å S= 1557 Å2 C2mm
From the XRD pattern of 1a at 85°C, a rectangular columnar phase (Colr3) was assigned (Fig. SI2). The presence of the (21) reflection combined with the absence of the (10) and (01) reflections allow the assignment of the P2gg plane group to this phase. For the other mesophases, the small number of observed reflections does not allow their unambiguous indexation. Nevertheless, considering the relative similarity of the four measured XRD patterns, these indexations have been derived from those determined for Colr3, and plane group P2mm was tentatively assigned to Colr0, Colr1, and Colr2.
SI7
Figure SI2. XRD pattern of 1a at 85°C and a zoom of 2° < 2θ < 15° region.
XRD data for 1c Upon the first heating, XRD of 1c revealed an unidentified disordered columnar mesophase (Colxd) at room temperature, which transits at ca. 85°C into a columnar oblique mesophase (Colo), and the latter transforms into a columnar rectangular phase (Colr2) slightly below the clearing point. Upon cooling, however, Colr2 transits at ca. 100°C into another columnar rectangular phase (Colr1), which remains stable until room temperature. Upon subsequent heating-cooling cycles, only Colr1/Colr2 and Colr2/I transitions are observed (DSC, POM, XRD).
SI8
Figure SI3. X-ray diffraction pattern of the columnar oblique phase (Colo) of 1c (120°C on first heating). The inset is a zoom of higher order reflections ([4°-15°] 2θ range).
Figure SI4. X-ray diffraction patterns of the low temperature columnar rectangular phase (Colr1) from two subsequent heating-cooling cycles. The inset is a zoom on the less intensive higher order reflections ([4°-15°] 2θ range).
SI9
Figure SI5`. X-ray diffraction patterns of the high temperature columnar rectangular phase (Colr2) from two subsequent heating-cooling cycles. The inset is a zoom on the less intensive higher order reflections ([4°-15°] 2θ range).
SI10
The cyclotetramerization of the phthalonitrile 2a in the presence of n-C5H11OLi in nC5H11OH did not produce the desired phthalocyanine 1a. Instead, an inseparable mixture of different phthalocyanines was obtained. MALDI-MS allowed the identification of some products, which result from the nucleophilic substitution of sulfone groups by the pentanolate anions (Figure SI6). The quasi-molecular ions corresponding to the products of two-, three-, or fourfold substitution were detected are observed (Figure SI87 C 12H 25 SO2
SO 2C 12 H 25
C12H 25 SO2 C12H 25SO2
CN
C12H 25SO2
CN
SO2 C 12 H25
N NH
N
N
N N
2a
N
C 12 H 25 SO2 C 12 H25SO 2
C 12 H25SO 2
SO2 C 12 H25
C 5 H11O
SO2 C 12 H25
C 12 H25 SO 2
OC 5 H11
N NH
N N
SO2 C12H 25
1a
N
N
SO 2C 12 H25
C 12 H25SO 2
OC 5 H11
N NH
C 12 H25SO 2
HN
N
N
HN
N N
N
N
SO2 C12 H25 C 12 H25SO 2
C 5H 11O
OC 5H 11
C 5H 11O
SO2 C12 H25 OC 5H 11
mixture of isomers
mixture of isomers
SO2 C12H 25
C12 H25SO2 C 12 H25SO 2
OC 5H 11
N NH
N
N
N N
C12 H25SO2
HN
HN N
C 5H 11 O
SO2 C12H 25 SO 2C 12 H25
mixture of isomers
Figure SI6. Products of cyclotetramerization of 2a with n-C5H11OLi/n-C5H11OH, which were identified by MALDI-MS (see Figure SI7)
SI11
Figure SI7. Mass-spectrum (MALDI) of the reaction mixture from the reaction of 2a with n-C5H11OLi/n-C5H11OH, see also Figure SI6. SI12
