Muscle-like supramolecular polymers: Integrated motion from thousands of molecular machines

Article abstract of DOI:10.1002/anie.201206571

Pumping iron: Double-threaded rotaxanes can be linked to coordination units and polymerized in the presence of iron or zinc ions. pH modulation triggers cooperative contractions (or extensions) of the individual rotaxanes, thus resulting in an amplified m

Full text of DOI:10.1002/anie.201206571

Supporting Information
ꢀ Wiley-VCH 2012
69451 Weinheim, Germany
Muscle-like Supramolecular Polymers: Integrated Motion from
Thousands of Molecular Machines**
Guangyan Du, Emilie Moulin, Nicolas Jouault, Eric Buhler,* and Nicolas Giuseppone*
anie_201206571_sm_miscellaneous_information.pdf

Synthetic procedures and products characterizations
All reagents and solvents were purchased at the highest commercial quality and used without
further purification unless otherwise noted. All reactions were carried out under an atmosphere
of argon unless otherwise stated. Dry solvents were obtained using a double column SolvTech
purification system. Microwave reactions were carried out with a single mode cavity Discover
Microwave Synthesizer (CEM Corporation, NC, USA), producing continuous irradiation at 2455
MHz and equipped with simultaneous external air-cooling system. Yields refer to
spectroscopically purified homogeneous materials (1H NMR). Thin Layer Chromatographies
were performed with TLC silica plastic sheets (Polygram SIL G/UV254, Macherey-Nagel) or
TLC alox plastic sheets (Polygram Alox N/UV254, Macherey-Nagel). In most cases, irradiation
using a Bioblock VL-4C UV-Lamp (6 W, 254 nm and/or 365 nm) as well as 10% ethanolic
phosphomolybdic acid and Ce-molybdate stainings were used for visualization. Preparative
Adsorption Flash Column Chromatographies were performed using silica gel (Geduran, silica
gel 60 (230 –400 mesh, 40 – 63 µm, Merck)) and aluminium oxide 90 (Merck; 70 - 230 mesh,
standardized activity II). ESI-MS spectra were performed on a Waters SQD mass spectrometer
(sample solutions were introduced into the mass spectrometer source with a syringe pump with a
flow rate of 20 µL.min-1). MALDI spectra were recorded on a Bruker Daltonics AutoflexII TOF
spectrometer. 1H NMR spectra were recorded either on a Bruker Avance 400 spectrometer at 400
13
MHz or on a Bruker Avance 400 spectrometer at 500 MHz and C NMR spectra either at 100
MHz or 125 MHz. The spectra were internally referenced to the residual proton solvent signal.
Residual solvent peaks were taken as reference (CDCl3: 7.26 ppm, CD3OD: 3.31 ppm, CD3CN:
1
1.94 ppm). For H NMR assignments, the chemical shifts are given in ppm. The following
1
notation is used for the H NMR spectral splitting patterns: singlet (s), doublet (d), triplet (t),
quadruplet (q), multiplet (m), broad (br).

Pseudorotaxane (8). This compound was synthesized according to the procedure described by
F. Coutrot et al.(1)
1H NMR (CDCl3, 400 MHz, 25°C): d = 6.91 (d, J = 8.3Hz, 2H), 6.84-6.71 (m, 10H), 6.57 (s,
2H), 4.44-4.38 (m, 2H), 4.35-4.29 (m, 2H), 4.23-3.63 (m, 48H), 3.56-3.36 (m, 4H), 2.09 (td, J =
6.9, 1.8Hz, 4H), 1.92 (brs, 2H), 1.48-1.14 (m, 16H); 13C NMR (CDCl3, 100 MHz, 25°C): d =
147.9, 147.8, 147.8, 147.0, 146.5, 146.3, 124.8, 123.2, 121.4, 121.2, 113.4, 112.7, 112.1, 112.0,
84.4, 72.6, 72.0, 71.3, 71.0 (x3), 70.6, 70.5, 68.8, 68.7, 67.8, 67.2, 67.1 (x2), 66.9, 52.4, 49.0,
28.2, 26.8, 26.4, 18.4; ESI-MS: calcd. for C66H96N2O16P2F12: 586.84 [M-2PF6]2+, found: 586.45.
%U
2 $F
4-Bromobenzyl acetate (2). (2) A solution of 4-bromobenzyl alcohol (4.00 g, 21.4 mmol) and
DMAP (268 mg, 2.14 mmol) in a 1:1 mixture of acetic anhydride/pyridine (40 mL) was stirred at
room temperature for 22 h until the starting material had been consumed as determined by TLC
analysis. Water (10 mL) and ethyl acetate (10 mL) were then added, and the layers were
separated. The organic layer was washed with HClaq. (10 mL, 1 M) and brine (10 mL). The
organic layer was then dried over Na2SO4, filtered, and concentrated in vacuo. Further
purification by flash chromatography (SiO2, n-hexane/EtOAc: 95/5) afforded compound 1 (4.45
g, 91%) as a pale yellow solid. Rf = 0.45 (n-hexane / EtOAc : 20/1); 1H NMR (CDCl3, 400 MHz,
25°C): d = 7.48 (d, J = 8.4Hz, 2H), 7.23 (d, J = 8.3Hz, 2H), 5.05 (s, 2H), 2.10 (s, 3H); 13C NMR
(CDCl3, 100 MHz, 25°C): d = 170.9, 135.1, 131.8, 130.1, 122.4, 65.6, 21.1; ESI-MS: calcd for
C9H9BrO2: 228.99 [M+H]+, found 229.13.
2

4-Trimethylsilylbenzyl acetate (3). (3) Trimethylsilyl acetylene (3.34 ml, 24 mmol) was added
to a solution of CuI (767 mg, 4 mmol), PdCl2(PPh3)2 (1.41 g, 2 mmol), PPh3 (1.06 g, 4 mmol)
and 4-bromobenzylacetate (4.61 g, 20 mmol) in triethylamine (30 mL). The mixture was
degassed by using freeze-thaw cycles and heated up to 70 °C for 36 h under a nitrogen
atmosphere. The resulting dark brown mixture was then filtered and the solvent was removed in
vacuo. Further purification by column chromatography (SiO2, n-hexane/EtOAc: 20/1) provided
1
compound 3 (4.56 g, 89%) as a pale yellow solid. Rf = 0.2 (n-hexane/EtOAc: 20/1); H NMR
(CDCl3, 400 MHz, 25°C): d = 7.44 (d, J = 8.4Hz, 2H), 7.30 (d, J = 8.4Hz, 2H), 5.07 (s, 2H), 2.08
13
(s, 3H), 0.25 (s, 9H); C NMR (CDCl3, 100 MHz, 25°C): d = 170.9, 136.4, 132.3, 128.0, 123.2,
104.8, 94.8, 65.9, 21.1, 0.1; ESI-MS: calcd for C14H18O2Si: 247.12 [M+H]+, found 247.15.
4-ethynylbenzyl acetate (4). A solution of 4-trimethylsilylbenzyl acetate (1.82 g, 8.9 mmol) in
THF (10 mL) was treated with TBAF (1M solution in THF, 0.8 mL, 0.8 mmol). The mixture was
stirred at room temperature for 30 min and the solvent was removed under reduced pressure.
Further purification by column chromatography (SiO2, n-hexane/EtOAc: 20/1) provided
1
compound 3 (1.10 g, 85%) as a pale yellow solid. Rf = 0.2 (n-hexane/EtOAc: 20/1); H NMR
(CDCl3, 400 MHz, 25°C): d = 7.48 (d, J = 8.2Hz, 2H), 7.31 (d, J = 8.4Hz, 2H), 5.09 (s, 2H), 3.09
13
(s, 1H), 2.11 (s, 3H); C NMR (CDCl3, 100 MHz, 25°C): d = 170.9, 136.8, 132.5, 128.2, 122.2,
83.4, 77.7, 65.9, 21.1; Anal. calcd. for C11H10O2: C 75.84, H 5.79; found C 75.17, H 5.86.
4'-[(Trifluoromethyl)sulfonyl]oxy]-2,2':6',2"-terpyridine (5). Terpyridone (6.68 g, 27.0
mmol) was dissolved in pyridine (70 mL) and the reaction mixture was cooled down to 0°C.
Trifluoromethanesulfonic anhydride (4.5 mL, 27.0 mmol) was added and the mixture was stirred
overnight at room temperature. Ice (45.0 g) was then added to the reaction mixture. The white
precipitate that formed was filtered, washed with cold water to give compound 5 (10.3 g, 100%)
1
as a white solid. H NMR (CDCl3, 400 MHz, 25°C): d = 8.72 (d, J = 4.8Hz, 2H), 8.62 (d, J =
3

7.8Hz, 2H), 8.42 (s, 2H), 7.89 (ddd, J = 7.7, 7.7, 1.7Hz, 2H), 7.39 (ddd, J = 7.4, 4.8, 1.0Hz, 2H);
13C NMR (CDCl3, 100 MHz, 25°C): d = 159.0, 158.7, 154.5, 149.6, 137.2, 124.9, 121.6, 118.7
(q, JCF = 320Hz), 113.3; ESI-MS: calcd for C16H10N3O3F3S: 382.05 [M+H]+, found 382.08;
Anal. calcd for C16H10N3O3F3S: C 50.40, H 2.64, N 11.02, found: C 50.05, H 2.81, N 10.91.
2,2':6,2?-terpyridinethynylbenzyl acetate (6). 2,2':6,2?-terpyridine triflate (2.12 g, 5.56 mmol)
was added to a solution of compound 4 (1.26 g, 7.23 mmol) in a mixture of triethylamine (40
mL) and tetrahydrofuran (10 mL). The mixture was degassed by using freeze-thaw cycles and
Pd(Ph3)4 (642 mg, 0.56 mmol) was added. The mixture was degassed once more by using freeze-
thaw cycles and then heated up to 65°C overnight under a nitrogen atmosphere. The resulting
dark brown mixture was filtered and the solvent was removed in vacuo. Further purification by
column chromatography (Al2O3, n-hexane/CH2Cl2: 10/1) yielded compound 4 (1.60 g, 71%) as a
1
white solid. Rf = 0.6 (Al2O3, n-hexane/CH2Cl2: 10/1); H NMR (CDCl3, 400 MHz, 25°C): d =
8.72 (ddd, J = 4.8, 1.7, 0.9Hz, 2H), 8.62 (ddd, J = 8.0, 1.0, 1.0Hz, 2H), 8.58 (s, 2H), 7.87 (ddd, J
3
= 7.8, 7.7, 1.8Hz, 2H), 7.57 (d, J = 8.2Hz, 2H), 7.39-7.34 (m, 4H), 5.13 (s, 2H), 2.13 (s, 3H);
13C NMR (CDCl3, 100 MHz, 25°C): d = 170.9, 155.8, 155.7, 149.3, 137.1, 137.0, 133.4, 132.3,
128.3, 124.2, 123.0, 122.5, 121.4, 93.4, 88.0, 65.9, 21.1; ESI-MS: calcd for C26H19N3O2: 406.16
[M+H]+, found 406.22.
1
1
1
1
2,2':6,2?-terpyridineethynylbenzyl azide (7). A solution of compound 6 (1.6 g, 3.9 mmol) in a
mixture of dichloromethane/methanol (9:1, 60 mL) was treated with sodium hydroxide (320 mg,
12 mmol) and the solution was stirred at room temperature for 1h. The solvent was then removed
in vacuo, and the resulting mixture was dissolved with a mixture of CH2Cl2 (50 mL) and water
(50 mL). The pH was then ajusted to 5~6 using dilute HCl (2M), and the aqueous phase was
4

extracted with CH2Cl2 (50 mL) and EtOAc (3*50 mL). The organic phases were combined, dried
over Na2SO4, and evaporated in vacuo to give 2,2':6,2?-terpyridineethynylbenzyl alcohol, which
was pure enough to be used as such in the next step. 1H NMR (CDCl3, 400 MHz, 25°C): d = 8.74
(d, J = 4.2Hz, 2H), 8.65 (d, J = 7.9Hz, 2H), 8.59 (s, 2H), 7.90 (ddd, J = 7.8, 7.8, 1.5Hz, 2H), 7.58
(d, J = 8.2Hz, 2H), 7.41-7.36 (m, 4H), 4.75 (s, 2H).
A solution of crude 2,2':6,2?-terpyridineethynylbenzyl alcohol in CH2Cl2 (10 mL) was cooled
down to 0°C and triethylamine (1.5mL, 10.8 mmol) and methanesulfonyl chloride (1.0mL, 12.9
mmol) were added. The reaction mixture was then stirred overnight at room temperature and
further dissolved with CH2Cl2 (70 mL). The organic phase was then extracted with water (50
mL) and NH4Clsat. (20 mL), dried over Na2SO4 and concentrated in vacuo to provide the
mesylated derivative, which was pure enough to be used as such in the next step.
A solution of crude 2,2':6,2?-terpyridineethynylbenzylmesylate in a 1:1 mixture of DMF and
THF (10 mL) was treated with sodium azide (1.5 g, 23 mmol) and heated up overnight to 50°C.
After cooling down to room temperature, the reaction mixture was diluted with CH2Cl2 (70 mL).
The organic phase was then extracted with water (50 mL) and NH4Clsat. (20 mL), dried over
Na2SO4 and concentrated in vacuo. Further purification by column chromatography (Al2O3, n-
hexane/CH2Cl2: 10/1) provided compound 7 (900 mg, 66% over 3 steps) as a white solid. Rf =
1
0.7 (n-hexane/CH2Cl2: 10/1? CH2Cl2); H NMR (CDCl3, 400 MHz, 25°C): d = 8.71 (d, J =
4.7Hz, 2H), 8.60 (d, J = 8.0Hz, 2H), 8.57 (s, 2H), 7.85 (ddd, J = 7.8, 7.8, 1.8Hz, 2H), 7.58 (d, J =
8.2Hz, 2H), 7.35-7.32 (m, 4H), 4.37 (s, 2H); 13C NMR (CDCl3, 100 MHz, 25°C): d = 155.7,
155.7, 149.3, 137.0, 136.5, 133.3, 132.5, 128.3, 124.1, 122.9, 122.6, 121.3, 93.3, 88.2, 54.4; ESI-
MS: calcd for C24H16N6: 389.15 [M+H]+, found: 389.21.
5

bis-2,2':6,2?-terpyridine rotaxane (9). To a solution of terpyridine azide 7 (106 mg, 0.27 mmol
) and pseudo-rotaxane 8 (200 mg, 0.13 mmol) in a mixture of dry CH2Cl2 (10 mL) and dry
CH3CN (4 mL) were added successively Cu(CH3CN)4PF6 (408 mg, 1.08 mmol) and 2,6-lutidine
(128 µL, 1.08 mmol). The reaction mixture was stirred for 5 min, then heated by microwave
irradiation (50 W) for 1h at 30°C and finally, stirred with an aqueous EDTA-disodium salt
solution adjusted to a pH˜ 8-9 (20 mL). The mixture was then extracted with a 3:1 mixture of
CH2Cl2/CH3CN (3*20 mL). The organic phases were combined, dried over Na2SO4 and finally
evaporated in vacuo. Further purification by column chromatography (Al2O3, CH2Cl2 ?
1
CH2Cl2/CH3OH: 100/1) yielded compound 9 (220 mg, 72%) as a yellow oil. H NMR (CDCl3,
400 MHz, 25°C): d = 8.71 (d, J = 4.1Hz, 4H), 8.62 (d, J = 7.9Hz, 4H), 8.56 (s, 4H), 7.87 (dd, J =
7.9, 7.2Hz, 4H), 7.57 (d, J = 8.1Hz, 4H), 7.36 (brdd, J = 6.1, 5.9Hz, 4H), 7.29 (d, J = 7.8Hz,
4H), 7.23 (s, 2H), 6.94-6.59 (m, 14H), 5.53 (s, 4H), 4.49-4.25 (m, 4H), 4.24-3.62 (m, 48H), 3.54-
3.28 (m, 4H), 2.62 (t, J = 8.1Hz, 4H), 1.75-1.54 (m, 8H), 1.39-1.27 (m, 8H); 13C NMR (CDCl3,
100 MHz, 25°C): d = 155.8, 155.7, 149.4, 148.6, 147.8, 147.7, 146.5, 146.2, 137.1, 136.1, 133.2,
132.7, 128.3, 124.8, 124.3, 123.1, 123.0, 122.9, 121.4, 121.3, 121.2, 120.8, 113.2, 112.8,
112.0(x2), 92.9, 88.5, 72.4, 72.0, 71.4, 71.0, 70.9, 70.5, 70.1, 69.6, 67.7, 67.2, 67.1, 66.9, 53.8,
52.3, 48.9, 29.2, 28.7, 26.8, 26.7, 26.6, 25.6; MALDI-TOF: m/z calcd for C114H128N14O16P2F12:
974.48 [M-2PF6]2+, found: 974.64.
bis-2,2':6,2?-terpyridine methylated rotaxane (1ext). Rotaxane 9 (45 mg, 0.02 mmol) and
Cu(OTf)2 (21.8 mg, 0.06 mmol) were dissolved in a 1:1 mixture of chloroform and acetonitrile
6

(6 mL). After stirring for 1h at room temperature, the solvents were evaporated in vacuo and a
1:1 mixture of iodomethane and acetonitrile (4 mL) was added. The mixture was stirred for 5
days at room temperature and, then solvents were evaporated in vacuo and the resulting solid
was washed with Et2O (10 mL) to give brown solid. This crude solid was dissolved in CH2Cl2
(20 mL) and the solution was stirred with an aqueous EDTA-disodium salt solution adjusted to a
pH˜ 8-9 (20 mL). The mixture was then extracted with a 3:1 mixture of CH2Cl2/CH3CN (3*20
mL). The organic phases were combined, dried over Na2SO4 and finally evaporated in vacuo. To
a solution of this crude residue in water (4 mL) was added NH4PF6 (30 mg, 0.18 mmol) and a 3:1
mixture of CH2Cl2/CH3CN (4 mL). The biphasic solution was stirred vigorously for 1h. The
aqueous layer was extracted with CHCl3 (3*20 mL). The organic layers were combined, dried
over Na2SO4 and concentrated in vacuo to give product 1ext (51 mg, quantitative) as a brown
1
solid. H NMR (CDCl3, 400 MHz, 25°C): d = 8.69 (brd, J = 4.0Hz, 4H), 8.62-8.56 (m, 4H),
8.54-8.48 (m, 4H), 8.30 (s, 1.33H), 8.20 (s, 0.67H), 7.85 (dd, J = 7.7, 7.7Hz, 4H), 7.56 (d, J =
8.1Hz, 4H), 7.48-7.44 (m, 4H), 7.37-7.32 (m, 4H), 7.05-6.64 (m, 12H), 5.64 and 5.62 (2x s, 4H,
isomers), 4.44-4.23 (m, 4H), 4.24-3.51 (m, 48H), 3.49-3.26 (m, 4H), 2.76 (t, J = 7.2Hz, 2.67H),
2.65 (t, J = 7.0Hz, 1.33H), 1.90-1.66 (m, 8H), 1.49-1.34 (m, 8H); 13C NMR (CDCl3, 125 MHz,
25°C): d = 155.8, 155.6, 151.0, 149.4, 149.2, 149.0, 147.7, 145.3, 145.0, 137.1, 132.9, 132.3,
129.6, 128.2, 128.0, 126.3, 124.3, 124.1, 122.9, 121.7, 121.4, 118.0, 114.4, 114.3, 92.7, 88.9,
71.4, 71.3, 71.0, 70.8, 70.7, 70.6, 70.0, 69.9, 69.8, 69.6, 69.5, 69.4, 68.2, 65.2, 57.0, 37.6, 27.0,
25.4, 25.0, 23.0, 22.9, 21.5; ESI-MS: m/z calcd for C116H134N14O16P4F24: 1134.469 [M-2PF6]2+,
found: 1134.766.
bis-2,2':6,2?-terpyridine methylated rotaxane (1cont). A solution of rotaxane 1ext (64 mg, 22.8
µmol) in chloroform (10 mL) was washed with an aqueous solution of NaOH 1M (10 mL). The
organic phase was dried over Na2SO4 and then evaporated in vacuo to provide compound 1cont
(55 mg, quantitative) as a brown solid. As expected, the compound is obtained as a mixture of
7

isomers (1), and only major isomer is described. 1H NMR (CDCl3, 500 MHz, 25°C): d = 8.66
(brd, J = 3.6Hz, 4H), 8.56 (brd, J = 7.8Hz, 6H), 8.49 (s, 4H), 7.83 (ddd, J = 7.7, 7.7, 1.5Hz, 4H),
7.54 (d, J = 7.8Hz, 4H), 7.47 (d, J = 7.6Hz, 4H), 7.33-7.31 (m, 4H), 7.01-6.62 (m, 14H), 5.67 (s,
4H), 4.40-4.28 (m, 4H), 4.22-3.97 (m, 18H), 3.90-3.52 (m, 30H), 3.47-3.29 (m, 4H), 2.76 (brs,
13
4H), 1.88-1.55 (m, 8H), 1.50-1.33 (m, 8H); C NMR (CDCl3, 125 MHz, 25°C): d = 155.6,
155.6, 155.4, 150.5, 149.2, 148.9, 148.7, 148.7, 148.5, 144.7, 136.9, 132.7, 132.3, 129.4, 128.4,
124.1, 123.8, 122.7, 121.7, 121.2, 121.2, 178.3, 114.5, 114.4, 111.9, 92.6, 88.7, 72.7, 70.7, 70.6,
70.5, 70.2, 69.6, 69.5, 69.4, 69.3, 69.1, 68.6, 64.8, 56.6, 49.0, 37.5, 27.0, 25.3, 24.9, 22.7, 21.5;
MALDI-TOF: calcd for C116H132N14O16P2F12: 988.497 [M-2PF6]2+, found: 988.597.
Procedures for polymerization of terpyridine rotaxanes
Contracted polymers: A solution of FeCl2 (3.2 mg, 25.0 × 10-3 mmol, 1.0 equiv.) in CD3CN
(1250 µL) was added rotaxane monomer 1cont (56.7 mg, 25.0 × 10-3 mmol, 1.0 equiv.) in CDCl3
(1250 µL). Immediately the colorless solution turned to purple and the mixture was stirred for 30
min at room temperature prior to further analyzes.
A solution of Zn(OTf)2 (9.1 mg, 25.0 × 10-3 mmol, 1.0 equiv.) in CD3CN (1250 µL) was added
rotaxane monomer 1cont (56.7 mg, 25.0 × 10-3 mmol, 1.0 equiv.) in CDCl3 (1250 µL). The
colorless solution was stirred for 30 min at room temperature prior to further analyzes.
Extended polymers: A solution of FeCl2 (3.2 mg, 25.0 × 10-3 mmol, 1.0 equiv.) in CD3CN (1250
µL) was added rotaxane monomer 1ext (64.0 mg, 25.0 × 10-3 mmol, 1.0 equiv.) in CDCl3 (1250
µL). Immediately the colorless solution turned to purple and the mixture was stirred for 30 min at
room temperature prior to further analyzes.
A solution of Zn(OTf)2 (9.1 mg, 25.0 × 10-3 mmol, 1.0 equiv.) in CD3CN (1250 µL) was added
rotaxane monomer 1ext (64.0 mg, 25.0 × 10-3 mmol, 1.0 equiv.) in CDCl3 (1250 µL). The
colorless solution was stirred for 30 min at room temperature prior to further analyzes.
8

Supplementary 1H NMR experiments
Procedures for acido-basic titrations of monomers 1ext and 1cont
Basic titration: A solution of 1ext (4 × 10-3 mmol) in CDCl3 and a solution of NaOD (0.2 mol/L)
in D2O were prepared separately. 2µL of NaOD solution was added to the 1ext solution for each
titration. The complete titration was finished after 22 times (up to 2.2 equiv.).
Acidic titration: A solution of 1cont (4 × 10-3 mmol) in CDCl3 and of d-TFA (0.2 mol/L) in CDCl3
were prepared separately. 2µL of d-TFA solution was added to the 1cont solution for each
titration. The complete titration was finished after 22 times (up to 2.2 equiv.). Finally, the
solution was washed with NaPF6 (sat.) aqueous solution to perform a micro-exchange counter
ion process.
•
•
Œ
Ž
A
•
•
”
1cont
+
•
•
‘
”
“
•
•
’
Œ
Ž
•
‘
’
“
8.5
8.0
7.5
7.0
6.5
6.0
5.5
ppm
•
•
•
Œ
Ž
•
•
•
•
1ext
Œ
Ž
‘
’ •
•
‘
”
“
’
”
“
8.5
8.0
7.5
7.0
6.5
6.0
5.5
ppm
B
”
1
ext + NaOD
1cont + H+
”
8.5
8.0
7.5
7.0
6.5
6.0
5.5
ppm
1
Fig. S1. (A) Characteristic H NMR shifts of the imidazolium proton number 9 in compounds
1cont and 1ext, together with (B) the superimposed spectra of 1ext + 2.2 eq. NaOD (leading to
1cont), and 1cont + 2.2 eq. d-TFA (leading to 1ext).
9

Supplementary UV-Vis experiments
1,2
0,7
0,6
0,5
0,4
0,3
0,2
0,1
0,0
A
B
C
ext
ext
1
1
1
cont
cont
1,0
1
ext
ext
Zn1
Fe1
Fe1
0,8
cont
cont
Zn1
0,6
0,4
0,2
0,0
300
400
500
600
700
800
300
400
500
600
700
800
Wavelength(nm)
Wavelength (nm)
Fig. S2. UV-Vis spectra comparison between monomers 1ext / 1cont and (A) polymers Zn1ext
/
Zn1cont (2.10-2 mM in 1:1 CDCl3/CD3CN) and (B) polymers Fe1ext / Fe1cont (1.10-2 mM in 1:1
CDCl3/CD3CN); (C) Image of two polymer solutions (Fe1cont and Zn1cont) at a concentration of
10 mM in a 1:1 CDCl3/CD3CN solvent mixture.
10

Supplementary scattering experiments
Neutron Scattering Experiments:
SANS experiments were carried out on the Pace spectrometer in the Léon Brillouin Laboratory
at Saclay (LLB, France). The chosen incident wavelength, l , depends on the set of experiments,
as follows. For a given wavelength, the range of the amplitude of the transfer wave vector q was
selected by changing the detector distance, D. Two sets of sample-to-detector distances and
wavelengths were chosen (D = 1.2 m, l = 5 ± 0.5 Å; and D = 4.7 m, l = 8± 0.5 Å) so that the
following q-ranges were respectively available: 3.54´ 10-2 £ q (Å-1) £ 3.65´ 10-1, and 5.2´ 10-3 £ q
(Å-1) £ 5.5´ 10-2. Measured intensities were calibrated to absolute values (cm-1) using
normalization by the attenuated direct beam classical method. Standard procedures to correct the
data for the transmission, detector efficiency, and backgrounds (solvent, empty cell, electronic,
and neutronic background) were carried out. The scattered wave vector, q, is defined by equation
1, where q is the scattering angle:
4p
l
q
2
q =
sin
(eq. S1)
The usual equation for absolute neutron scattering combines the intraparticle scattering S1(q) =
Vchainf volP(q) form factor with the interparticle scattering S2(q) factor
2
2
I(q)(cm- 1 ) =
(
Dr) (S1 (q) + S2 (q)
) (Dr) (Vchainfvol P(q) + S2 (q))
=
(eq. S2)
where (Dr )2=(r monomer-r solvent)2 is a contrast per unit volume between the polymer and the solvent
and was determined from the known chemical composition. r = Snibi/(Snimiv´ 1.66´ 10-24)
represents the scattering length per unit volume, bi is the neutron scattering length of the species
i, mi the mass of species i, and v the specific volume of the monomer (which was measured and
been taken to be equal to 0.704 cm3g-1) or the solvent (i.e., 0.77 cm3g-1 for 50/50
CDCl3/CD3CN). P(q) is the form factor, Vchain=Nvm´ 1.66´ 10-24 is the volume of the N
11

monomers (of mass m) in a chain and f vol is the volume fraction of monomer. In the high q-
range, the scattering is assumed to arise from isolated chains; i.e., S2(q) = 0, and thus I(q) µ P(q).
Dynamic and Static Light Scattering Experiments:
In the dynamic light scattering experiments (DLS), the normalized time autocorrelation
function, g(2)(q,t), is measured as a function of the scattered wave-vector, q, given by
q=(4pn/l )sin(q/2), where n is the refractive index of the solvent (1.39 for 50/50 CDCl3/CD3CN
at 20 °C), and q is the scattering angle. In our experiments, q was varied between 30° and 140°,
which corresponds to scattering wave vectors, q, in the range from 7.2×10-3 to 2.6×10-2 nm-1.
The measurements used a 3D DLS spectrometer (LS Instruments, Fribourg, Swiss) equipped
with a 25mW HeNe laser (JDS uniphase) operating at l =632.8 nm, a two channel multiple tau
correlator (1088 channels in autocorrelation), a variable-angle detection system, and a
temperature-controlled index matching vat (LS Instruments). The scattering spectrum was
measured using two single mode fibre detections and two high sensitivity APD detectors (Perkin
Elmer, model SPCM-AQR-13-FC). Solutions were filtered through 0.2 mm PTFE Millipore filter
into the cylindrical scattering cell.
In Static Light Scattering (SLS) experiments, the excess of scattered intensity is measured
with respect to the solvent. The absolute scattering intensity (i.e., the excess Rayleigh ratio in
cm-1) can be deduced by using a toluene sample reference for which the excess Rayleigh ratio is
well-known (Rtoluene=1.3522´ 10-5 cm-1 at 633 nm):
æ
ö2
Isolution - Isolvent
n
Rsolute (cm- 1 ) =
´
´ Rtoluene (cm- 1 )
(eq. S3)
ç
ç
÷
÷
Itoluene
ntoluene
è
ø
The usual equation for absolute light scattering combines the form factor P(q), the structure
factor S(q) and the weight-average molecular weight MW of the scattered objects:
2
4p 2n2 dn
æ
ö
(eq. S4)
R(q) =
CM P(q)S(q)
W
ç
÷
NAl4
dc
è
ø
12

C is the solute concentration in g/cm3. The scattering constant is K=4p2n2(dn/dC)2/NAl 4 where
dn/dC is the refractive index increment (measured using a Mettler Toledo PortableLab
refractometer) and NA is Avogadro’s number (K=3.23x10-8, 5.54x10-6, and 3.53x10-6 cm2.g-2.mol
respectively for Zn1cont, Fe1cont, and Fe1ext).
In DLS the experimental signal is the normalized time autocorrelation function of the
scattered intensity:
I(q,0)I(q,t)
g(2) (q,t) =
(eq. S5)
2
I(q,0)
The latter can be expressed in terms of the field autocorrelation function or equivalently in terms
of the autocorrelation function of the concentration fluctuations, g(1)(q,t), through:
g(2) (q,t) - 1 = a + b g(1) (q,t) 2
(eq. S6)
Where a is the baseline (varying between 1´ 10-4 and 2´ 10-4 depending on the scattering angle
and/or the system) and b the coherence factor, which in our experiments is varying between 0.7
and 0.9 depending on the samples. The normalized dynamical correlation function, g(1)(q,t), of
polymer concentration fluctuations is defined as:
dc(q,0)dc(q,t)
g(1) (q,t) =
(eq. S7)
dc(q,0)2
Where dc(q,t) and dc(q,0) represent fluctuations of the polymer concentration at time t and zero,
respectively.
In our experiments, some of our solutions were characterized by a single relaxation
mechanism with a characteristic relaxation time inversely proportional to q2. The extrapolation
of (t cq2)-1 to q=0, where t c is the average relaxation time of g(1)(q,t), yields the mutual diffusion
coefficient D. The latter is related to the average apparent hydrodynamic radius, RH, of the
species through the Stokes-Einstein relation:
13

kBT
D =
(eq. S8)
6phs RH
Where kB is the Boltzmann constant, hs the solvent viscosity (0.444 cP for 50/50 CDCl3/CD3CN
at T=20°C), and T the absolute temperature.
To determine the sizes as well as the size distributions, especially when solutions were
characterized by several relaxation mechanisms (e.g. monomers and polymers), we have used the
Contin method based on the inverse Laplace transform of g(1)(q,t). If the spectral profile of the
scattered light can be described by a multi-Lorentzian curve, then g(1)(q,t) can be written as:
¥
g(1) (q,t) = G(G)exp(- Gt)dG
(eq. S9)
ò
0
Where G(G) is the normalized decay constant distribution.
Worm-like chain model:
To interpret the scattering and extract the structural parameters, it is also very useful to have a
correct expression of the scattering of an individual chain, P(q). We have used an expression (4,
5) based on the expressions derived by Burchard and Kajiwara for rodlike structure (6) in which
the form factor calculated by Sharp and Bloomfield (7) for finite wormlike chains of contour
length Lc is used at low q.
é
b ù
2L
2qL
æ
p ö
÷
ø
æ
p ö
2
[
exp(- x) + x - 1
]
é 4
7
11
7
ù
æ
ö
ç
ç
è
ç
ç
÷
P(q) =
+
+
-
+
exp(- x)
÷
´ expê-
ú
ç
ê
ú
x2
15 15x 15 15x
ë
Lc
a
÷
÷
(eq. S10)
è
ø
ê
ú
û
è
ø
ë
û
æ
ö
ö
÷
ú
û
é
ù
ú
æ
2qL
æ
öb
1
p
÷
p
ç
ç
ç
ç
÷
÷
+
+
´ 1- expê-
2
ç
÷
ç
÷
ø
2Lc Lpq
qLc
a
ê
è
ø
è
ø
è
ë
With x=LcLpq2/3 and valid for Lc>4Lp. Values of the empirical parameters a =5.53 and b=5.33,
which contribute to the balance between the low-q and large-q terms, have been optimized in ref.
4. Polydispersity and excluded volume effects can be neglected in the regime qRG>1 where the
14

scattering experiments were performed (ref. 25 of the main text); with RG being the radius of
gyration of the chains.
High-q data can be fitted by a Guinier expression for the form factor of the polymer section:
æ
ç
è
2 ö
pS
q
q2Rc
(eq. S11)
ç
÷
÷
VchainP(q) =
exp -
2
ø
10-1
10-2
10-3
ext
TRPM
1
Fit Guinier
cont
TRDM
1
Fit guinier
10-2
10-1
100
q / Å-1
Fig. S3. SANS data for solutions of 1ext and 1cont (10 mM in 1:1 CDCl3/CD3CN at T=20°C). The
dashed lines represent the best fits of the data obtained using a classical Guinier expression (see
eq. S14)
To determine the density d of the compounds we used the SANS measurements of the monomer
solutions (without metals) as shown in Fig. S3. Indeed the scattering intensity extrapolated to
q=0 can be expressed as follows:
fDr2 M° CDr2M°2
I0 =
=
(eq. S12)
dNa
d2Na
With C being the monomer concentration, ? ?²=(?-?solvent)² the contrast term, M° the molar mass
of the monomer, Na the Avogadro number and d the density.
As the density is also present in the calculation of the contrast term we have to determine d
which satisfies the following relation:
15

d2
Dr2
CM°2
=
(eq. S13)
I0Na
Hence, the extrapolation of the intensities to q=0 gives I =0.0185cm-1 for 1ext and I0=0.021 cm-1
0
for 1cont. Using these values and the relation S13 we thus obtained a density of 1.42g/cm3 and
1.30 g/cm3 for respectively 1ext and 1cont
.
Finally we can also determine the radius of gyration Rg of the monomers using the Guinier
relation:
- q²Rg ²
(eq. S14)
I(q) = I0 exp(
)
3
We obtained Rg=8.9+/-0.1Å for both monomers.
Table S1: Values of key parameters used in this study and determined from SANS on monomers
1ext and 1cont (solutions in 1:1 CDCl3/CD3CN at T=20°C). n.b. Here the MO term is different from
Table 1 because it does not include metal ions in the monomeric form.
Dr2 (x
CM°2
C
(mM)
M°
(g/mol)
I0 (cm-1)
Rg
(nm)
d (g/cm3)
Scattering
length
1020cm-4)
I0Na
(x10-21
g2/cm2)
density (x
1010cm-2)
1ext
10
10
2560
2268
0.0185
0.0210
0.89+/-
0.1
5.88
1.42+/-
0.14
2.17
1.99
3.4596
4.1616
1cont
0.89+/-
0.1
5
1.30+/-
0.13
16

A
B
1
0,8
0,6
0,4
0,2
0
1
0,8
0,6
0,4
0,2
0
ext
TRPP Fe
TRDP
Fonet
Fe1c
Fe1
20°C
35°C
50°C
20°C
35°C
50°C
1
10
100
1000
1
10
100
1000
Radius / nm
Radius / nm
Fig. S4. Hydrodynamic radii (RH) distribution obtained using the Contin method in DLS at
q=90° for (A) Fe1cont and (B) Fe1ext (in both case, c=10 mM in 1:1 CDCl3/CD3CN).
107
106
105
104
103
102
107
106
105
104
103
102
A
B
Fe1ext
Fe1cont
20°C
35°C
50°C
Fit wormlike chain
20°C
35°C
50°C
Fit wormlike chain
10-4
10-3
10-2
10-1
100
10-4
10-3
10-2
10-1
100
q / Å-1
q / Å-1
Fig. S5. Combined SLS and SANS measurements as a function of the temperature for solutions
of (A) Fe1cont and (B) Fe1ext (10 mM in 1:1 CDCl3/CD3CN). The continuous line represents the
data fit by the wormlike chain model (eq. S10).
17

References
1. Coutrot, F.; Romuald, C.; Busseron, E. Org. Lett. 10, 3741- 3744 (2008).
2. Bertrand, M. B.; Neukom, J. D.; Wolfe, J. P. J. Org. Chem. 73, 8851-8860 (2008).
3. Hiraoka, S.; Hirata, K.; Shionoya, M. Angew. Chem., Int. Ed. 29, 3814-3818 (2004).
4. J. S. Pedersen, P. Schurtenberger, Scattering Functions of Semiflexible Polymers with and
without Excluded Volume Effects. Macromolecules 29, 7602-7612 (1996).
5. F. Bonnet, R. Schweins, F. Boué, E. Buhler, Suppression of aggregation in natural-
semiflexible/flexible polyanion mixtures, and direct check of the OSF model using SANS. Eur.
Phys. Lett. 83, 48002 (2008).
6. W. Burchard, K. Kajiwara, Statistics of stiff chain molecules. I. Particle scattering factor.
Proc. R. Soc. London A316, 185-199 (1970).
7. P. Sharp, V. A. Bloomfield, Light scattering from wormlike chains with excluded volume
effects. Biopolymers 6, 1201-1211 (1968).
18