A thermoreversible supramolecular polyurethane with excellent healing ability at 45 ºC

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1 A thermoreversible supramolecular polyurethane with excellent healing ability at 45 ºC Antonio Feula, a Alexander Pethybridge, a Ioannis Giannakopoulos, b Xuegang Tang, b Ann M. Chippindale, a Clive R. Siviour, b C. Paul Buckley b and Wayne Hayes a* a Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD (UK); Fax: (+ 44) ; w.c.hayes@reading.ac.uk b Department of Engineering Science, Oxford University, Parks Road, Oxford, OX1 3PJ (UK) Supporting information Synthesis of N-(4-methoxybenzyl)-1-(4-nitrophenyl)methanamine Figure S1. 1 H NMR spectrum of N-(4-methoxybenzyl)-1-(4-nitrophenyl)methanamine in CDCl 3 at 25 ºC Figure S2. 13 C NMR spectrum of N-(4-methoxybenzyl)-1-(4-nitrophenyl)methanamine in CDCl 3 at 25 ºC Figure S3. 1 H NMR spectrum of bis(4-(4-(3-(4-methoxybenzyl)-3-(4 nitrobenzyl)ureido)phenyl)carbamate) terminated Krasol HLBH P2000 in CDCl 3 at 25 ºC Figure S4. 13 C NMR spectrum of bis(4-(4-(3-(4-methoxybenzyl)-3-(4- nitrobenzyl)ureido)phenyl)carbamate) terminated Krasol HLBH P2000 in CDCl 3 at 25 ºC Figure S5. FT-IR spectrum of polyurethane 1 at 30 ºC Figure S6. FT-IR spectrum of polyurethane 1 at 60 ºC Figure S7. DSC thermogram of polyurethane 1 Synthesis of 1-(4-methoxybenzyl)-1-(4-nitrobenzyl)-3-phenylurea 2 Figure S8. 1 H NMR spectrum of 1-(4-methoxybenzyl)-1-(4-nitrobenzyl)-3-phenylurea 2 in CDCl 3 at 25 ºC. Figure S9. 13 C NMR spectrum of 1-(4-methoxybenzyl)-1-(4-nitrobenzyl)-3-phenylurea 2 in CDCl 3 at 25 ºC Solid state structure determination Table S1. Crystallographic data for compound 2 Figure S10. Asymmetric unit and numbering scheme for compound 2 Figure S11. A portion of the packed structure of compound 2 showing π π stacking interactions between adjacent phenyl rings. Figure S12. a) Frequency sweep for supramolecular polyurethane 1 at different temperatures; b) Loss modulus master curve plot for supramolecular polyurethane 1 Figure S13. Data from repeated frequency sweeps on a single specimen during three temperature cycles Figure S14. Macro-scale healing process for polyurethane 1 at the temperature of 45 C S2 S3 S3 S4 S4 S5 S5 S6 S7 S8 S8 S9 S10 S11 S12 S13 S14 S15 S1

2 Figure S15. Micro-scale healing process for polyurethane 1 at the temperature of 45 C Figure S16. The stress-strain curves for supramolecular polyurethane with different healing times References S16 S17 S18 Synthesis of N-(4-methoxybenzyl)-1-(4-nitrophenyl)methanamine 1,2 (4-Methoxyphenyl)methanamine (16 mmol, 2.19 g) was added to a solution of 4- nitrobenzaldehyde (13 mmol, 2.00 g) in ethanol (25 ml) and the mixture was stirred for four hours at 50 C. Ethanol was removed in vacuo and the imine was purified by quick filtration through a silica plug (ethyl acetate). Sodium borohydride (1.5 eq) was added to a solution of the imine (1.0 eq.) in methanol (25 ml) and the mixture was stirred for four hours at room temperature. Methanol was removed in vacuo, water was added and the product was extracted three times with ethyl acetate which was removed in vacuo to afford the product as an orange oil (3.50 g, 99%). IR (Neat) 3098, 3024, 3008, 2963, 2932, 2913, 2835, 1676, 1639, 1605, 1600, 1580, 1510, 1443, 1440, 1417, 1378, 1340, 1298, 1295, 1245, 1219, 1179, 1144, 1106; 1 H NMR (δ; 400 MHz; CDCl 3 ) 3.81 (3H, s), 4.82 (2H, s), 6.90 (2H, d, J = 4.0), 7.26 (2H, d, J = 6.0), 7.93 (2H, d, J = 8), (2H, m), 8.43 (1H, s); 13 C NMR (δ; 100 MHz; CDCl 3 ) 55.3, 64.6, 114.1, 123.8, 128.9, 129.4, 130.5, 141.7, 149.0, 158.9, S2

3 Figure S1. 1 H NMR spectrum of N-(4-methoxybenzyl)-1-(4-nitrophenyl)methanamine in CDCl 3 at 25 ºC Figure S2. 13 C NMR spectrum of N-(4-methoxybenzyl)-1-(4-nitrophenyl)methanamine in CDCl 3 at 25 ºC. S3

4 H a H b H c H c H a H b H b H a H c Figure S3. 1 H NMR spectrum of bis(4-(4-(3-(4-methoxybenzyl)-3-(4 nitrobenzyl)ureido)phenyl)carbamate) terminated Krasol HLBH P2000 in CDCl 3 at 25 ºC δ (ppm) Figure S4. 13 C NMR spectrum of bis(4-(4-(3-(4-methoxybenzyl)-3-(4- nitrobenzyl)ureido)phenyl)carbamate) terminated Krasol HLBH P2000 in CDCl 3 at 25 ºC S4

5 cm cm cm cm cm-1 A cm cm cm cm cm cm cm cm cm cm cm cm cm cm cm cm cm cm cm-1 Name 30 degc Description Sample 027 By user Date Wednesday, July Figure S5. FT-IR spectrum of polyurethane 1 at 30 ºC cm cm cm cm cm cm-1 A cm cm cm cm cm cm cm cm cm cm cm cm cm cm cm cm cm-1 Name 60 degc Description Sample 030 By user Date Wednesday, July Figure S6. FT-IR spectrum of polyurethane 1 at 60 ºC S5

6 Figure S7. DSC thermogram of polyurethane 1 S6

7 Synthesis of 1-(4-methoxybenzyl)-1-(4-nitrobenzyl)-3-phenylurea 2 (4-Methoxybenzyl)-1-(4-nitrophenyl) methanamine (4.2 mmol, 1.14 g) was added to phenyl isocyanate (4.2 mmol, 0.50 g) in dry THF and the reaction was left stirring for 30 minutes at 50 ºC. The solvent was removed in vacuo and the product was obtained in 92% yield as a yellow powder. Mp 107 C. IR (Neat) 3329, 3259, 3113, 3060, 2995, 2931, 2831, 1639, 1595, 1521, 1509, 1499, 1452, 1442, 1402, 1341, 1311, 1296, 1234, 1170, 1153, 1106; 1 H NMR (δ; 400 MHz; CDCl 3 ) 3.82 (3H, s), 4.49 (2H, s), 4.76 (2H, s), 6.38 (1H, s), (2H, m), (1 H, m), (8 H, m), (2 H, m), (2 H, m); 13 C NMR (δ; 100 MHz; CDCl 3 ) 50.7, 55.4, 114.7, 119.9, 123.5, 124.0, 127.8, 128.1, 128.5, 128.9, 138.6, 145.5, 147.5, 155.8, S7

8 Figure S8. 1 H NMR spectrum of 1-(4-methoxybenzyl)-1-(4-nitrobenzyl)-3-phenylurea 2 in CDCl 3 at 25 ºC δ (ppm) Figure S9. 13 C NMR spectrum of 1-(4-methoxybenzyl)-1-(4-nitrobenzyl)-3-phenylurea 2 in CDCl 3 at 25 ºC S8

9 Solid state structure determination A crystal of compound 2 was mounted under Paratone-N oil and flash cooled to 150 K under nitrogen in an Oxford Cryosystems Cryostream. Single-crystal X-ray intensity data were collected using an Agilent Gemini S Ultra diffractometer (Cu Kα radiation (λ = Å). The data were reduced within the CrysAlisPro software. 3 The structures was solved 4 using the program SIR92 and all non-hydrogen atoms located. Least-squares refinements on F were carried out using the CRYSTALS suite of programs. 5 The non-hydrogen atoms were refined anisotropically. All the hydrogen atoms were located in difference Fourier maps, then those attached to C and N were placed geometrically with a C H distance of 0.93 Å or a N-H distance of 0.86 Å and a U iso of 1.2 times the value of U eq of the parent atom. The fractional coordinates of the H atoms attached to the N atoms were refined freely whilst those of the hydrogen atoms attached to C were then refined with riding constraints. All the crystals of compound 2 were found to be racemic twins. There are two molecules of 1- (4-methoxybenzyl)-1-(4-nitrobenzyl)-3-phenylurea in the asymmetric unit. The solid state figures were drawn using CAMERON (Watkin, D.J., Prout, C.K. & Pearce, L.J. (1996). CAMERON, Chemical Crystallography Laboratory, Oxford, UK). S9

10 Table S1. Crystallographic data for compound 2 2 Formula C 22 H 21 N 3 O 4 M r Crystal system Monoclinic Space group P 2 1 /c Z 8 a /Å (4) b/å (8) c /Å (10) β / (5) V / Å (3) D calc / g cm Crystal habit Yellow plate Crystal dimensions /mm Radiation Cu K α ( Å) T /K 150 µ /mm R(F), Rw(F) 6.08, 7.14 Asymmetric unit and numbering scheme for compound 2 S10

11 Figure S10. Asymmetric unit and numbering scheme for compound 2 S11

12 Figure S11. A portion of the packed structure of compound 2 showing π π stacking interactions between adjacent phenyl rings. The centroid to plane distance is Å. S12

13 Storage Modulus (Pa) C -25 C -20 C -15 C -10 C 0 C 10 C 20 C 30 C 40 C 50 C 60 C 70 C 80 C ω/(rad/s) Figure S12a. Frequency sweep for supramolecular polyurethane 1 at different temperatures, these data were used to generate the master curve in Figure Storage Modulus (Pa) α Τ ω/(rad/s) Figure 12b. Loss modulus master curve plot for supramolecular polyurethane 1 S13

14 5x Storage Modulus (Pa) 4x10 6 3x10 6 2x10 6 Temperature 20 C first cycle second cycle third Storage Modulus (Pa) Temperature 50ºC first cycle second cycle third cycle ω (rad/s) ω (rad/s) Storage Modulus (Pa) Temperature 80ºC first cycle second cycle third cycle ω (rad/s) Figure S13. Data from repeated frequency sweeps on a single specimen during three temperature cycles, indicating that the properties did not change significantly between cycles. S14

15 Figure S14. Macro-scale healing process for polyurethane 1 at the temperature of 45 C (every 10 minutes). A Peltier heating system was used to maintain the temperature at 45 C during the healing process. S15

16 Figure S15. Micro-scale healing process for polyurethane 1 at the temperature of 45 C: the whole image of the initial cut, a, b, c is the image from different location of the cut; the image during healing after 30 minutes, 60 minutes, 90 minutes, and 120 minutes from A to D, and the image of A, B and C is from the location c of the cut, and image D is from location a of the cut. S16

17 Figure S16. The stress-strain curves for supramolecular polyurethane with different healing times. The pristine sample was annealed at the temperature of 45 C for 2 hours. Zero value means that the sample cannot be tested. The ends of the curves represent specimen failure. S17

18 References 1. Ahmed, B.; Yusuf, M. Indian J. Chem. Sect. B-Organic Chem. Incl. Med. Chem. 2010, 49, Modak, A.; Dutta, U.; Kancherla, R.; Maity, S.; Bhadra, M.; Mobin, S. M.; Maiti, D. Org. Lett. 2014, 16, Agilent Technologies (2012), Agilent Technologies UK Ltd., Oxford, UK, Xcalibur/SuperNova CCD system, CrysAlisPro Software system, Version Altomare, A.; Cascarano, G.; Giacovazzo, C.; Guagliardi, A.; Burla, M.C.; Polidori, G.; Camalli, M. J. Appl. Cryst., 1994, 27, Betteridge, P.W.; Carruthers, J.R.; Cooper, R.I.; Prout, C.K.; Watkin, D.J. J. Appl. Cryst., 2003, 36, S18