Supporting Information. Visible Light Mediated Photopolymerization in Single Crystals: Photomechanical Bending and Thermomechanical Unbending

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1 Supporting Information Visible Light Mediated Photopolymerization in Single Crystals: Photomechanical Bending and Thermomechanical Unbending Ranita Samanta, a Subhrokoli Ghosh, b Ramesh Devarapalli, a C. Malla Reddy a, * a R Samanta, Dr. R. Devarapalli, Dr. C M. Reddy Department of Chemical Sciences Indian institute of Science education and Research (IISER) Kolkata, Mohanpur Campus, Mohanpur , India. b S. Ghosh Department of Physical Sciences Indian institute of Science education and Research (IISER) Kolkata, Mohanpur Campus, Mohanpur , India. cmallareddy@gmail.com 1

2 Table of Contents 1) Instrumentation methods S1 2) Experimental procedure S2 3) Conversion yield of PBIT-dodeca 2 S3 4) 1 H NMR spectra of BIT-dodeca 2 Figure S1 5) 13 C NMR spectra of BIT-dodeca 2 Figure S2 6) UV-Visible spectra of BIT-dodeca 2 monomer Figure S3 7) Differential scanning calorimetry of PBIT-dodeca 2 Figure S4 8) Thermogravimetric analysis of monomer BIT-dodeca 2 Figure S5 9) Face indexing image of PBIT-dodeca 2 Figure S6 10) Bending Unbending experiment: snapshots Figure S7 11) ORTEP diagram of the monomer BIT-dodeca 2 Figure S8 12) ORTEP diagram of polymer PBIT-dodeca 2 Figure S9 13) Crystallograpic data table of monomer and polymer Table S1 Instrumentation methods (S1) X-Ray Diffraction Data.Asingle crystal of eachbit-dodeca 2 and PBIT-dodeca 2 was mounted separately on a glass pip. Intensity data werecollected on Oxford Diffraction SuperNova, Eos diffractometer with graphite-monochromatic Mo Kα radiation (λ= å) at 100K. The crystal was kept at 100 K during data collection. Using Olex2, the structure was solved with the ShelXT structure solution program using direct methods and refined with the ShelXL refinement package using least square methods. Thermal Studies.DSC was conducted on a Mettler-Toledo DSI1 STAR e instrument. Accurately weighed samples (2-3 mg) were placed in hermetically sealed aluminium crucibles (40 μl) and scanned from 30 C to 300 C at a heating rate of 10 C/min under a dry nitrogen atmosphere (flow rate 80 ml/min). The data were managed by STAR e software. TGA was performed on a Mettler-Toledo TGA/SDTA 851 e instrument. Approximately 5 mg of the sample was added to an aluminium crucible and heated from 30 to 350 C at a rate of 10 C/min under continuous nitrogen purge. 1 H-NMR and 13 C-NMR.NMR analysis of BIT-dodeca 2 was performed on a JEOL 400 MHz NMR in CDCl 3 at 25 C. UV-Visible spectra. UV-VIS spectra were recorded with a Hitachi U-4100 UV-vis spectrophotometer. Setup for photomechanical bending. 1) As illumination source a standard microscope lamp source (HBO 100- Carl Zeiss) was used. The light was made collimated and then focused by using standard optics in order to make the focal spot size to be 3 mm, which is of the order of the width of the crystal. The power of the lamp was held fixed at 50mW. The crystals were mounted individually on the tip of a tooth-peak with the help of standard glue (araldite) and the system was mounted on the focal plane of the illumination lamp. A webcam of 30 frames/sec was used to record the bending dynamics of the crystals. A UV (400nm) cutoff filter was used in some experiments to cut off the UV light. 2

3 2) Pegasus Shanghai Diode laser (wavelength- 405 nanometer). Diameter of the beam is 3 mm and power is 50 mw (full power). Experimental Procedure (S2) Materials. All the chemicals reported in this study were purchased from Sigma Aldrich and used as received. Synthesis procedure [2,2'-Bi-1H-indene]-3,3'-dihydroxy-1,1'-dione (BIT-OH 2 ) was prepared according to the literature procedure. [1] 1,1 -dioxo-1h-2,2 -biindene-3,3 -diyl didodecanoate (BIT-dodeca 2 ). To a 250 ml schlenk flask, BIT-OH 2 (0.50 g) was added and dissolved in 50 ml of dry dichloromethane (DCM) under nitrogen protection. The mixture was cooled to 0 Cbefore1.8 ml of triethylamine was added to it. After 30 min lauroly chloride (1.5 ml) was added drop wise to the solution at 0 C. After stirring at room temperature for 6 hours, 50 ml water was added to quench the reaction. Then it was purified through silica gel column. Large size single crystals of BIT-dodeca 2 were prepared by dissolving 15 mg of the compound in 4 ml DCM and 2 ml ethanol and by slow evaporation method at ambient conditions (in ~ 48hours). 1 H NMR (CDCl 3, 600MHz): 7.43 (d, J = 7.2 Hz, 2H), 7.37 (t, J = 7.2 Hz, 2H), 7.26 (t, J = 6.6 Hz, 2H), 7.10 (d, J = 7.2 Hz, 2H), 2.64 (t, 4H), 2.23 (m, 4H), 1.74 (m, 4H), 1.56 (m, 8H), 0.90 (t, 6H). 13 C NMR (CDCl 3, 150MHz): , , , , , , , , , , 33.34, 31.41, 29.64, 24.66, 22.69, Conversion yield calculation (S3). To calculate the conversion yield, 32.5 mg of PBIT-dodeca 2 (B) was extracted by Soxhlet apparatus with DCM and chloroform for about 5 hours (6 times). We obtained 31.3 mg of residue after dried in vacuum (Yield 96.3 %) 3

4 Fig. S1. 1 H NMR spectrum of BIT-dodeca 2 in CDCl 3 at 298 K. 4

5 Fig. S2. 13 C NMR spectrum of BIT-dodeca 2 in CDCl 3 at 298 K. 5

6 Fig. S3.UV-Vis absorption spectra of BIT-dodeca 2 in dichloromethane (~0.016 mg/ml). Fig. S4.Differential scanning calorimetry of PBIT-dodeca 2 under nitrogen protection (heating and cooling rate = 10 C/ min ). 6

7 Fig. S5.Thermogravimetric analysis of monomer BIT-dodeca 2 Fig. S6. Image of face indexing of PBIT-dodeca 2 crystal 7

8 Fig. S7. Snapshorts of crystals during photomechanical bending-thermomechanical unbending during light irradiation-thermal heating (in hot oven) cycles. Notice the shape recovery in the unbent crystals after thermal treatment. 8

9 Fig. S8. ORTEP diagram of the monomer BIT-dodeca 2. The atomic displacement ellipsoids are drawn at the probabiliyt level of 50 %. Fig. S9. ORTEP diagram of the polymer PBIT-dodeca 2. The atomic displacement ellipsoids are drawn at the probabiliyt level of 50% 9

10 Crystallographic and Structure Refinement Parameters ofbit-dodeca 2 (monomer) and PBIT_dodeca 2 (polymer)..table S1.Crystallographic and structurerefinement parameters of crystal BIT-dodeca 2 (monomer) and crystal PBIT-dodeca 2 (polymer). BIT- dodeca 2 (monomer) PBIT- dodeca 2 (polymer) Formula C 42 H 54 O 6 C 42 H 54 O 6 Formula Weight Crystal System Monoclinic Monoclinic Space group P2 1 /c P2 1 /c a/ Å (15) (4) b/å (3) (7) c/å (16) (4) α/ β/ (9) (2) γ/ V/ Å (2) (5) Z D c / g cm μ /mm F(000) θ range/ Reflections collected Unique reflections R int Goodness of fit (F 2 ) R1 (I > 2σ(I)) wr2(i > 2σ(I)) S CCDC No References [1] Dou, L.; Zheng, Y.; Shen, X.; Wu, G.; Fields, K.; Hsu, W.; Zhou, H.; Yang, Y.; Wudl, F. Single-Crystal Linear Polymers Through Visible Light-Triggered Topochemical Quantitative Polymerization. Science 2014, 343,