Ultrasound-induced gelation of a giant macrocycle† †Electronic supplementary information (ESI) available: Detailed synthetic procedures, 1H and 13C NMR spectra of all compounds, experimental details for the gelation including a video, molecular modelling methods, single crystal and powder diffractio

Supramolecular gelation of a 68-membered macrocycle triggered by sonication.


Sonogel formation
Preparation of sonogels CH 3 CN was added to a vial containing compound wool into a vial. A gel was formed upon sonication of the vial for a VWR USC100T ultrasonic bath stable-to-inversion-of-a-test-tube method. Figure S1. Ultrasound-induced gelation of compound to right, the images show two identical initial solutions of solution (ii) for 60 s while solution (i) is the negative the disassembly of the gel after dilution with CHCl Figure S2 shows the HPLC chromatogram of the gel in order to show that there is no sonication and gel formation. Figure S2. HPLC chromatogram of compound gel and dilution with CHCl 3 . Conditions gradient 5-95% B in 3 minutes + isocratic 95% B for 2 minutes ( + 0.1% formic acid). S2 was added to a vial containing compound 1. The solution was filtered through cotton into a vial. A gel was formed upon sonication of the vial for 60 s (see supporting video) in VWR USC100T ultrasonic bath (45 KHz, ). The gel state was evaluated by the tube method.
induced gelation of compound 1 in CH 3 CN at 14 mM (a) and 1.4 mM (b). two identical initial solutions of 1 (i and ii), the aspect after sonication on (i) is the negative control, the appearance after resting after dilution with CHCl 3 .
shows the HPLC chromatogram of macrocycle 1 before and after the formation of that there is no degradation or chemical transformation .
HPLC chromatogram of compound 1: a) before formation of sonogel; b) after formation of the Conditions: UPLC CSH C18 Column, 2.1 x 50 mm, flow rate: 0.6 ml/min 3 minutes + isocratic 95% B for 2 minutes (A: H 2 O + 0.1% formic acid, B: . The solution was filtered through cotton (see supporting video) in The gel state was evaluated by the CN at 14 mM (a) and 1.4 mM (b). From left (i and ii), the aspect after sonication of he appearance after resting for 24 h is and before and after the formation of degradation or chemical transformation of 1 upon : a) before formation of sonogel; b) after formation of the flow rate: 0.6 ml/min, O + 0.1% formic acid, B: acetonitrile S3 Figure S3 shows the attempt to form a gel upon heating and cooling of a solution of 1 in CH 3 CN. Formation of a gel is observed in the same solution after sonication. The same procedure for the gelation of compound 1 was applied to compounds S16, 2 and 3. As shown in Figure S4, no gelation was observed in any case. Figure S4. Attempts to form a gel upon sonication of solutions of compounds S16, 2 and 3. (a) Solution (ii) is a solution of S16 (9 mM) in CH 3 CN after being sonicated for 5 minutes while solution (i) is the same solution before sonication. (b) Solution (ii) is a solution of 2 (1.4 mM) in CH 3 CN after being sonicated for 5 minutes while solution (i) is the negative control. (c) Solution (ii) is a solution of 2 (14 mM) in CH 3 CN after being sonicated for 5 minutes while solution (i) is the negative control. (d) Solution (ii) is a solution of 3 (12 mM) in CH 3 CN after being sonicated for 5 minutes while solution (i) is the same solution before sonication.

Gel thermostability
T gel was determined using the "dropping ball method". S1 A stainless steel ball (63 mg, 2.5 mm in diameter) was placed on the surface of the gel, prepared in a glass tube as described in the text. The sample was placed in an oil bath and heated in steps of 5 o C from 40 o C until the ball started dipping into the gel ( Figure S5). Figure S5. Determination of T gel using the "dropping ball method"

X-ray crystallography X-ray structure of compound 3 (CCDC 1838654)
Pure compound 3 (3 mg) was dissolved in CHCl 3 (1 mL), and the mixture was filtered to a vial and sealed with a plastic cap, resulting in crystallization after 5 days at room temperature. Crystals suitable for X-ray crystallography were selected using an optical microscope and examined at 180 K on a Nonius KappaCCD diffractometer using Mo Kα radiation (λ = 0.7107 Å). All non-hydrogen atoms were refined anisotropically. Hydrogen atoms were placed in idealized position. . X-ray structure of derivative 3 in ORTEP view (ellipsoids are drawn at 50% probability level).

X-ray Powder Diffraction
Powder X-ray diffraction (PXRD) was performed at room temperature on a Panalytical Empyrean diffractometer emitting Cu Kα (1.540598 Å + 1.544426 Å) radiation. X-ray powder diffractogram was recorded in the 2θ range 3-45° (step size 0.02°, time/step 200 s). Figure S7. X-ray diffraction patterns of the as-synthesized compound 1 (top) and of the xerogel obtained after sonication of a solution of 1 in CH 3 CN and deposition on the sample holder.

Molecular modelling calculations
Molecular mechanics calculations were performed using MacroModel implemented in Maestro 11 (Schrödinger release 2016-4). S2 The structure of macrocycle 1 was simplified by replacing the 3,5-di-tert-butylbenzyl capping groups by methyl groups to save computational time. The structure was minimized first and the minimized structure was then used as the starting molecular structure for the MacroModel conformational search. The conformational search was performed twice from a different starting conformation. The force field used was OPLS3 as implemented in this software (CHCl 3 solvation). The charges were defined by the force field library and no cut off was used for non-covalent interactions. A Polak-Ribiere Conjugate Gradient (PRCG) was used and each minimisation was subjected to 10.000 iterations. The minima converged on a gradient with a threshold of 0.01. Conformational searches were performed from previously minimized structures using 100 steps per rotatable bond (maximum number of steps of 10.000). Images were created using PyMol. S3

NMR dilution and variable temperature experiments
1 H NMR dilution experiment of compound Avance TCI Cryoprobe spectrometer addition of neat CD 3 CN and the NMR recorded at each Figure S8. (a) Chemical structure of gelator of 1 at different concentrations in CD Variable temperature NMR performed in a Bruker 500 MHz AVIII HD Smart Probe spectrometer Chiller unit. The temperature of the sample was changed using the NMR spectrometer, and the sample was allowed to equilibrate in thermometer gave a stable temperature MR experiment of compound 1 (3.3 mM sample in a Bruker 500 MHz AVIII HD Smart Probe spectrometer equipped with a BCU Chiller unit. The temperature of the sample was changed using the internal thermostat of the spectrometer, and the sample was allowed to equilibrate in the probe until the probe thermometer gave a stable temperature ( Figure S9).

Transmission Electron Microscopy
The morphology of the gel was studied by using TEM at room temperature (25 °C). A 5 mM solution of the gel was prepared following the procedure described above. 4 μL of this solution was placed on a TEM grid (300 mesh size Cu grid) coated with a holey carbon film. The grid was allowed to dry by slow evaporation in air for 30 minutes and then under high vacuum for 4 hours. TEM images were recorded using a JEOL JEM LaB6 filament operating at 250kV. Images were recorded using a Gatan 794 CCD camera.

Scanning Electron Microscopy (SEM)
The same TEM grid was coated with 10nm Pt using a Quorum Technologies Q150T ES coater prior to SEM characterisation. Images were taken using a TESCAN MIRA3 FEG 5kV.

icroscopy (TEM)
The morphology of the gel was studied by using TEM at room temperature (25 °C). A 5 mM solution of the gel was prepared following the procedure described above. 4 μL of this solution placed on a TEM grid (300 mesh size Cu grid) coated with a holey carbon film. The grid was allowed to dry by slow evaporation in air for 30 minutes and then under high vacuum for 4 hours. TEM images were recorded using a JEOL JEM-3010 electron microscope f LaB6 filament operating at 250kV. Images were recorded using a Gatan 794 CCD camera. micrographs of a xerogel formed by compound 1 at different

Scanning Electron Microscopy (SEM)
grid was coated with 10nm Pt using a Quorum Technologies Q150T ES coater prior to SEM characterisation. Images were taken using a TESCAN MIRA3 FEG-EM micrographs of a xerogel formed by compound 1 at different . The morphology of the gel was studied by using TEM at room temperature (25 °C). A 5 mM solution of the gel was prepared following the procedure described above. 4 μL of this solution placed on a TEM grid (300 mesh size Cu grid) coated with a holey carbon film. The grid was allowed to dry by slow evaporation in air for 30 minutes and then under high vacuum for 4 3010 electron microscope fitted with a LaB6 filament operating at 250kV. Images were recorded using a Gatan 794 CCD camera. at different magnifications. grid was coated with 10nm Pt using a Quorum Technologies Q150T ES coater -SEM operating at different magnifications.

Synthesis and characterization of described compounds Synthesis
The synthesis of gelator 1 involved the preparation of dipropargylamide building blocks S2 and S5 (Scheme 1). Amide coupling of dipropargylamine and mono-methyl terephthalate using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) gave S2 in quantitative yield. Basic hydrolysis of S2 followed by ester coupling of carboxylic acid S3 with monoprotected hydroquinone S4 gave access to S5 in good yield. Scheme S1. Synthesis of building blocks S2 and S5.
As shown in Scheme S2, the synthesis of the dicarboxylic acid S10 started with the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction of S2 with an excess of 1-(azidomethyl)-3,5-di-tert-butylbenzene S6 to give a mixture compounds S7 and S8 that were separated by chromatography. CuAAC reaction of compound S7 with 1,4bis(azidomethyl)benzene S9 followed by basic hydrolysis of the methyl ester afforded S10 in excellent yield. Hydrolysis of S8 gave the corresponding monocarboxylic acid S11 in good yield. Following a similar strategy, compound S5 was reacted with azide S6 to give S12 and S13, which were separated by chromatography (Scheme S3). S10 Scheme 2. Synthesis of carboxylic acids S10 and S11. Scheme S3. Synthesis of phenol derivatives S14 and S15.

S11
Removal of the silyl protecting groups yielded phenols S14 and S15. Ester coupling of the carboxylic acid dimer S10 with S14 gave compound S16 in good yield (Scheme S4), and CuAAC macrocyclisation of S16 with one equivalent of diazide S9 under high dilution conditions afforded gelator 1. Scheme S4. Synthesis of macrocycle 1.
Control compounds containing fragments of macrocycle 1 were synthesised in order to obtain insights into the relationship between the chemical structure and the self-assembly properties. Ester coupling of S11 with S15 afforded 2 (Scheme S5), which is an acyclic analogue that contains most of the functional groups present in 1. The diisopropylamide derivative 3 is another acyclic analogue that contains only the diester diamide moiety of 1. The synthesis of 3 is shown in Scheme S6. Amide coupling of S17 with diisopropylamine gave diisopropylamide S18 in quantitative yield. Basic hydrolysis of S18 followed by ester coupling with hydroquinone afforded 3. Scheme S5. Synthesis of 2.

General experimental details
All the reagents and materials used in the synthesis of the compounds described below were bought from commercial sources, without prior purification. Thin layer chromatography was carried out using with silica gel 60F (Merck) on glass plates. Flash chromatography was carried out on an automated system (Combiflash Rf+ or Combiflash Rf Lumen) using prepacked cartridges of silica (25μ PuriFlash® columns). All NMR spectroscopy was carried out on a DPX400 or AVIII400 spectrometer using the residual solvent as the internal standard. All chemical shifts (δ) are quoted in ppm and coupling constants given in Hz. Splitting patterns are given as follows: s (singlet), bs (broad singlet), d (doublet), t (triplet), q (quadruplet), m (multiplet). FT-IR spectra were measured on a PerkinElmer Spectrum One spectrometer equipped with an ATR cell. Melting points were measured in a Mettler Toledo MP50 Melting Point System. ES+ was carried out on a Waters Xevo G2-S bench top QTOF machine.
Compounds S1 and S17 are commercially available. Compounds S6 S4 and S9 S5 were prepared according described procedures.
LiCl (3x), H 2 O (1x) and brine. The organic fraction was dried (MgSO 4 ), and concentrated in vacuo. Pd-C (10 wt%, 1.3 g, 1.25 mmol) was added to a solution of the obtained crude in EtOAc (30 mL). The whole system was evacuated and backfilled with H 2 and this protocol was repeated three times. Then the heterogeneous mixture was allowed to stir at 25 °C under a positive pressure of hydrogen. After 1 h, the reaction mixture was filtered directly through Celite. The crude material was purified by flash column chromatography on silica gel (gradient from 0% to 10%of EtOAc in Pet. Ether) to afford S4 (2.672 g, 95 %) as a white solid.