Supporting Information

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1 Supporting Information Well-Defined and Precision-Grafted Bottlebrush Polypentenamers from Variable Temperature ROMP and ATRP William J. Neary, Brandon A. Fultz, and Justin G. Kennemur* Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA * Table of Contents: 1. Materials, Characterization, and Methods p Synthesis of CPBIB p Figure S1. CPBIB 1 H NMR p Figure S2. CPBIB 13 C NMR p Figure S3. CPBIB HMQC p Figure S4. CPBIB Total Ion Chromatograph (TIC) p Figure S5. CPBIB Mass Spectrum p Determination of CPBIB Ring Strain via VT- 1 H NMR p Figure S6. PCPBIB Percent Conversion Overlay p Figure S7. PCPBIB Percent Conversion Overlay (Zoomed) p Determination of Ceiling Temperature (T c ) of CPBIB p Synthesis of PCPBIB via VT-ROMP p Figure S8. PCPBIB 1 H NMR p Figure S9. PCPBIB 13 C NMR p Figure S10. PCPBIB 1 H NMR End Group Analysis p Figure S11. PCPBIB COSY End Group Analysis p Figure S12. PCPBIB Crude Conversion Determination p Figure S13. PCPBIB Cis-Trans Ratio Determination p Preparation of PCPBIB-graft-styrene, (PCPBIB-g-S) p. 12 1

2 20. Figure S14. PCPBIB-g-S 1 H NMR p Figure S15: TGA of PCPBIB(61) and PCPBIB(61)-g-S(49) P Figure S16. PCPBIB-g-S of varying N sc SEC Overlay p Figure S17. PCPBIB-g-S varying N 1 sc H NMR Overlay p Table S1. Specific refractive index values for PCPBIB-g-S samples p Synthesis of PCPBIB(82)-g-[S(23)-b-MMA(100)] p Table S2. Sample set for core-shell bottlebrush polymer p Figure S18. PCPBIB-g-(S-b-MMA) 13 C NMR p Figure S19. PCPBIB-g-(S-b-MMA) DSC p Figure S20. PCPBIB-g-(S-b-MMA) TGA p Figure 21. AFM 1 µm amplitude image p Figure 22. AFM 1 µm phase image p Figure 23. AFM 0.5 µm amplitude image p Figure 24. AFM 0.5 µm phase image p. 21 2

3 Materials: Activated basic alumina, activated neutral alumina, acetic acid (glacial), anisole (99%), α-bromoisobutryl bromide (BIBB) (98%), chloroform-d, copper bromide (99%), cuprous bromide (98%), dicyclopentadiene, ethyl vinyl ether (99%), magnesium sulfate ( 99%), N,N,N,N,N -pentamethyldiethylenetriamine (PMDETA) (99%), methyl methacrylate (MMA) (99%), peroxyacetic acid (39% in acetic acid), sodium carbonate ( %), styrene (S), trimethylamine (TEA) (>99%), and toluene-d 8 were purchased from Sigma-Aldrich and used as received unless otherwise noted. Lithium aluminum hydride (LAH) (97%) was purchased from Alfa Aesar and was used as received. Hexane and ethyl acetate (EtOAc) were purchased from EMD Millipore and was used as received. 3-Cyclopenten-1-ol (3CPOH) was synthesized according to previous literature. 1 Toluene, dichloromethane (DCM), tetrahydrofuran (THF), and diethyl ether (DEE) were obtained from an SG Waters glass contour solvent purification system that was packed with neutral alumina, and the solvents were passed through a 2 µm filter before being dispensed. Anisole, S, MMA, and PMDETA were stirred over basic alumina for 10 minutes and filtered before use to remove inhibitors. CuBr was purified by stirring over glacial acetic acid overnight. The suspension was filtered, washed with EtOH three times followed by three successive washes of DEE and was dried via high vac at 25 ºC for 2 days. Grubbs first-generation catalyst (G1) and Hoveyda Grubbs second-generation catalyst (HG2) were generously donated by Materia Inc. and used as received. Characterization: 1 H NMR experiments were performed on a Bruker Avance III at 600 and 400 MHz unless otherwise noted. Variable temperature (VT) 1 H NMR experiments were conducted on a Bruker Avance III at 500 MHz capable of temperatures between 5 and 55 C. All 1 H NMR experiments on polymer samples were allowed a s relaxation delay as determined necessary through a T1 analysis. Absolute molar mass (M w ) and dispersity (Đ) of each sample was determined on an Agilent Wyatt combination triple detection size exclusion chromatography (SEC) instrument containing three successive Agilent PLgel Mixed-C columns which have a linear MW operating range of 0.2-2,000 kg mol -1, an Agilent 1260 infinity series pump, degasser, autosampler, and thermostated column chamber. The columns were calibrated with 10 narrow Đ samples of poly(styrene) (PS) ranging from 2-1,800 kg mol -1. The Wyatt triple detection unit hosts a minidawn TREOS multi-angle light scattering (MALS) detector (658 nm), an Optilab TrEX refractive index detector, and a Viscostar II differential viscometer. The specific refractive index increment (dn/dc) of ml g -1 for PCPBIB in THF at 25 C was obtained by analyzing the refrective index change at various concentrations in THF. The dn/dc values of PCPBIB-g-S samples were determined using the weight fraction of PS and PCPBIB determined via 1 H NMR. Differential scanning calorimetry (DSC) experiments were performed on a TA Instruments Model Q100 with an RCS 90 cooling accessory. A heating rate of 10 C/min under nitrogen flow (40 ml/min) was used. Thermogravimetric analysis (TGA) was performed on a TA Instruments Model Q600 from 100 to 700 ºC under argon at a heating rate of 10 ºC min -1. AFM height images were obtained with an MFP-3D AFM equipped with an ARC2 controller (Asylum Research) using Nanoworld ARROW-NCR Al-coated silicon 3

4 tips, 10 nm nominal radius, and a force constant between 27 and 80 N m -1. AFM tips were calibrated under air, and the cantilever was tuned to 10% below the resonance frequency. Images were collected using a 1.0 Hz scan rate with 256 points and lines in tapping mode. AFM samples were created by dip-casting freshly cleaved mica discs into dilute solutions of polymer (10-5 and 10-6 w/w in CHCl 3 ). After dip casting, samples were dried in a vacuum oven at 50 ºC for 4 hrs prior to imaging. Synthesis of cyclopent-3-en-1-yl-2-bromo-2-methylpropanoate (CPBIB): To an oven dried round bottom flask equipped with a magnetic stir bar, 3CPOH (8.87 g, 100 mmol), TEA (17.63 ml, 126 mmol), and 250 ml of THF was added under argon followed by cooling to 0 C. A mixture of BIBB (29.1 g, 124 mmol) in 220 ml of THF was added to an addition funnel and was added drop-wise for 2 hours. After complete addition, the reaction was stirred for 20 hrs at 23 ± 2 C. The reaction was filtered, concentrated, and the oil was diluted in EtOAc. A separatory funnel was used to wash the product with 100 ml of 0.1 M Na 2 CO 3 and twice with brine (100 ml). The organic layer was then dried over MgSO 4, filtered, and concentrated. The crude product was then purified via column chromatography (100:1 Hexane:EtOAc) and further purified via fractional vacuum distillation (40 ºC, 0.1 mmhg) to afford g (93.1% yield) of product. 1 H NMR (CDCl 3 ): δ (ppm) 5.72 (s, 2H), 5.43 (tt, J = 6.9, 2.5 Hz, 2H), (m, 4H), 1.91 (s, 6H). 13 C NMR (CDCl 3 ): δ (ppm) 171.6, 128.2, 75.9, 56.2, 39.4, Figure S1: 1 H NMR (CDCl 3, 25 ºC) of purified CPBIB. 4

5 Figure S2: 13 C NMR (CDCl 3, 25 ºC) of purified CPBIB. Figure S3: HMQC NMR (CDCl 3, 25 ºC) of purified CPBIB. 5

6 d:\desktop\...\27280_blank_gcms 11/3/ :50:31 AM CHCl3 Blank RT: Relative Abundance Time (min) Figure S4: The total ion chromatographs (TIC) for the chloroform blank (top) and CPBIB (bottom). The sample showed a single peak, indicating it was pure NL: 5.79E6 TIC MS 27280_blank _gcms NL: 1.80E8 TIC MS 27280_4- br4rylcyc5en e_gcms 27280_4-br4rylcyc5ene_gcms 11/3/2017 1:16:00 AM 4-bromobutyryl cyclopentene 27280_4-br4rylcyc5ene_gcms # RT: AV: 6 SB: , NL: 4.13E7 T: + c Full ms [ ] x10 x Relative Abundance m/z Figure S5: The mass spectrum at RT min for the sample CPBIB. Although the molecular ion peak (m/z = 233) was not observed, the observed fragments are consistent with the structure provided. The peaks at m/z = 167 and 169 are consistent with the predicted acylium ion and the peaks at m/z = 149 and 151 are consistent with the predicted fragmentation of the bromoisobutyrate group. 6

7 Determination of CPBIB polymerization enthalpy and entropy via VT-H NMR: A clean NMR tube, equipped with a septum, was purged for 5 min with argon. To the NMR tube, g (1.38 mmol, ml) of CPBIB was added. In a 1 ml volumetric flask, 5.5 mg (8.77 µmol) of HG2 was added and diluted to the volumetric mark with toluene-d 8. To the NMR tube, ml of the catalyst solution was added to give [M] 0 = 2.26 M and 0.23 mol% HG2. The tube contents were mixed and placed into the NMR spectrometer at 25 ºC. Analysis was performed at regular time intervals over the course of approximately one hour. At this time equilibration of monomer conversion to polymer was confirmed by the integration ratio of signature monomer protons versus those of the polymer protons (Figure S6 and S7). The process was repeated at temperatures of 20, 15, 10, and 5 ºC with each successive temperature providing a new equilibrium monomer concentration that decreased with decreasing temperature. Figure S6: Equilibrated VT- 1 H NMR (toluene-d 8 ) of the polymerization of CPBIB using HG2 from 5-25 ºC. 7

8 Figure S7: Expanded 1 H NMR showing the ppm region of the monomer (CPBIB) and resulting polymer methine protons after VT- 1 H NMR equilibration in toluene-d 8. (Catalyst = HG2, 0.23 mol%). Comparison of the integration of these peaks provides direct observation of [M] eq at the various temperatures analyzed (5 25 ºC). Determination of the Ceiling Temperature (T c ) of CPBIB The thermodynamic values ( H p = kj mol -1 and S p = J mol -1 K -1 ) allow for determination of the ceiling temperature (T c ) for CPBIB as defined in Eq 1. 2 (1) where [M] bulk = 5.62 M is the bulk concentration of CPBIB based on its density (ρ (23 C) =1.31 g cm -3 ). The resulting T c = 103 C. Synthesis of PCPBIB via VT-ROMP: As a representative example; a clean flame-dried round bottom flask equipped with a magnetic stir bar and septa was purged with argon for 10 min. To the flask, g (11.4 mmol) of CPBIB was added. In a separate 4 ml flame dried vial equipped with a flea stir bar, g of G1 was added and capped with a septum. The vial was then purged gently for 5 minutes with argon before 3.5 ml of THF was added and allowed to stir until dissolved. To the monomer, 3.05 ml of the catalyst solution ([M] 0 = 2.25 M, [M] 0 /[I] 0 = 100) was added and allowed to stir at 50 ºC for 5 minutes. The solution was then quickly transferred to an isothermal bath at 0 ºC and allowed to stir for 5 hrs. At that 8

9 time, 0.2 ml of ethyl vinyl ether was added to terminate the reaction and was allowed to stir at 0 ºC for 30 min. The sample was then opened to the atmosphere and a small aliquot was taken for NMR and SEC analysis. The solution was then diluted slightly with toluene and stirred in neutral alumina to remove the residual catalyst. The solution was filtered, slightly concentrated, and precipitated into ice-cold methanol. Redissolution and precipitation was performed twice more to ensure purified polymer. The polymer was then collected and dried in a vacuum oven at 25 ºC for 10 hrs to yield PCPBIB. Percent Conversion = 64.4%, M n, theo. = 15.0 kda, M n (MALS) = 14.6 kda, Đ (MALS) = H NMR (CDCl3): δ (ppm) 5.44 (br s, 2H), 4.87 (br s, 1H), 2.29 (br s, 4H), 1.89 (s, 6H). 13C NMR (CDCl3): δ (ppm) 171.6, 128.2, 75.9, 56.2, 39.4, Figure S8: 1 H NMR (CDCl 3, 25 ºC) of PCPBIB(71) M n = 16.6 kg mol -1, Đ =

10 Figure S9: 13 C NMR (CDCl 3, 25 ºC) of PCPBIB(71). M n = 16.6 kg mol -1, Đ = 1.18 Figure S10: 1 H NMR (CD 2 Cl 2, 25 ºC) of synthesized PCPBIB(63) for end group analysis. M n,nmr = 17.7 kg mol -1 (M n,mals = 14.6 kg mol -1 ). 10

11 Figure S11: 1 H- 1 H NMR (CD 2 Cl 2, 25 ºC) of synthesized PCPBIB(63) for end group analysis. Figure S12: Percent conversion determination of crude aliquots of PCPBIB(63) in CDCl 3 at 25 ºC. Percent conversion was taken as: %. 100% where the Area A was set to

12 Figure S13: Inverse gated decoupling 13 C NMR of PCPBIB(63) for the determination of trans:cis backbone content. Preparation of PCPBIB -graft-styrene, (PCPBIB -g-s): In a flame dried Schlenk flask equipped with a magnetic stir bar, a 50 mg ml -1 solution of PCPBIB in dry toluene was prepared. The solution was freeze pump thawed (FPT d) until no air was present in the sample and then backfilled with dry nitrogen. In a separate Schlenk flask, 13.4 g (129 mmol, 600 eq.) of styrene, ml (86 µmol, 0.4 eq.) of PMDETA, 1.4 mg (6 µmol, 0.03 eq.) of CuBr 2, and 1 ml (0.215 mmol, 1 eq.) of PCPBIB were added and FPT d. Once complete, the solution was allowed to stir at room temperature for 1 hr. At that time, 12.3 mg (86 µmol) of CuBr was added under a positive nitrogen flow, resealed, and placed into a preheated oil bath at 80 ºC. Aliquots were taken at various time points and each aliquot was cooled with dry ice, opened and diluted with toluene. The crude solution was then passed through two neutral alumina plugs to remove residual copper and was precipitated 3 times into MeOH. The polymer was then collected and dried in a vacuum oven overnight at 80 ºC. 1 H NMR (CDCl 3 ): δ (m), 5.08 (br s), (m), (m), (m). 12

13 Figure S14: 1 H NMR (CDCl 3, 25 ºC) of synthesized PCPBIB-g-S. The M n of the grafts can be determined by the ratio of peak integration of olefin backbone repeating unit protons (A, 2H) to the repeating unit styrene aryl protons (G, 5H). Figure S15: TGA of PCPBIB(61) and PCPBIB(61)-g-S(49) (Ar, rate = 10 C min -1 ). Dashed lines indicate 5% mass loss temperature. 13

14 Figure S16: GPC-MALS traces of PCPBIB(61) and PCPBIB(61)-g-S of various N sc. Figure 17: 1 HNMR of PCPBIB(61)-g-S synthesized. Annotated DP = N sc 14

15 Table S1. Specific refractive index values for PCPBIB-g-S samples Time dn/dc M Sample ID n,mals (h) (ml g -1 ) * (kg mol -1 ) PCPBIB(63)-g-S(8) PCPBIB(63)-g-S(15) PCPBIB(63)-g-S(21) PCPBIB(63)-g-S(28) PCPBIB(61)-g-S(5) PCPBIB(61)-g-S(10) PCPBIB(61)-g-S(18) PCPBIB(61)-g-S(34) PCPBIB(61)-g-S(44) PCPBIB(61)-g-S(49) * Specific refractive index = (φ PS dn/dc PS ) + (φ PCPBIB dn/dc PCPBIB ), φ = weight fraction. Synthesis of PCPBIB(82)-g-[S(23)-b-MMA(100)]: PCPBIB(82) and PCPBIB(82)-g-S(23) were synthesized in accordance to the procedure described above and results given in Table S1. To a 100 ml oven-dried Schlenk flask equipped with a stir bar, 0.23g of P(CPBIB-g-S) (87.5 µmol of repeat unit) was added and 3 vacuum/nitrogen cycles were applied to remove all oxygen. In a separate flask, a solution containing ml of MMA, g of CuBr 2, 0.1 ml of PMDETA, and 122 ml of anisole was made and freeze-pump thawed until no oxygen was present. The solution was then allowed to stir at room temperature for 2 hours to dissolve all of the CuBr 2. To the Schlenk flask, 30 ml of this solution was added and was stirred until P(CPBIB-g-S) dissolved. Once homogeneous, g of CuBr (35 µmol) was added under a positive nitrogen flow, capped, and allowed to stir at 70 ºC for 3 hours. At this time, the flask was opened and diluted with THF in an ice bath to quench the reaction. The solution was run through a neutral alumina plug and precipitated twice in methanol. The polymer was then dried at 80 ºC in a vacuum over for 12 hours. Table S2. Sample set for core-shell bottlebrush polymer ID Conv. [%] a) M n,theo. [kg mol -1 ] b) M n,mals [kg mol -1 ] c) M n,nmr [kg mol -1 ] d) Đ c) PCPBIB_ PCPBIB_82-g-S_ PCPBIB_82-g-(S_23-b-MMA_100) a) Percent conversion determined by 1 H NMR (CDCl 3, 25 ºC). b) Theoretical molar mass based on monomer-to-catalyst ratio and corrected for % conversion. c) Number-average molar mass and dispersity determined by MALS-SEC in THF at 25 C d) Determined by 1 H NMR (CDCl 3, 25 ºC). 15

16 Figure S18: 13 C NMR (CDCl 3, 25 ºC) of PCPBIB(82)-g-[S(23)-b-MMA(100)]. Figure 19: Differential scanning calorimetry thermogram of PCPBIB(82)-g-[S(23)-b- MMA(100)]. Heating was performed at a rate of 10 C min and the data shown was taken upon the second heating (Exo down). Triangle annotates the midpoint T g value. 16

17 Figure 20: (a) Thermogravimetric analysis of PCPBIB(82)-g-[S(23)-b-MMA(100)] under Ar and a heating rate of 10 C min -1. The dashed lines are a guide for the eye to the temperature at which 5% mass is lost. 17

18 Figure 21: AFM amplitude (1.0 µm scan size) image obtained from dip casting freshly cleaved mica into a 10-6 w/w solution of PCPBIB(82)-g-[S(23)-b-MMA(100)] in CHCl 3 before drying in a vacuum oven at 50 ºC for 12 hours prior to imaging. 18

19 Figure 22: AFM phase (1.0 µm scan size) image obtained from dip casting freshly cleaved mica into a 10-6 w/w solution of PCPBIB(82)-g-[S(23)-b-MMA(100)] in CHCl 3 before drying in a vacuum oven at 50 ºC for 12 hours prior to imaging. 19

20 Figure 23: AFM amplitude (0.5 µm scan size) image obtained from dip casting freshly cleaved mica into a 10-6 w/w solution of PCPBIB(82)-g-[S(23)-b-MMA(100)] in CHCl 3 before drying in a vacuum oven at 50 ºC for 12 hours prior to imaging. 20

21 Figure 24: AFM phase (0.5 µm scan size) image obtained from dip casting freshly cleaved mica into a 10-6 w/w solution of PCPBIB(82)-g-[S(23)-b-MMA(100)] in CHCl 3 before drying in a vacuum oven at 50 ºC for 12 hours prior to imaging. References: (1) Zohrabi-Kalantari, V.; Wilde, F.; Gruenert, R.; Bednarski, P. J.; Link, A. 4- Aminocyclopentane-1,3-diols as platforms for diversity: synthesis of a screening library. MedChemComm 2014, 5, (2) Hiemenz, P. C.; Lodge, T., Polymer Chemistry. 2nd ed.; CRC Press: Boca Raton,