Supporting Information for the Manuscript Entitled Stereospecific, Coordination Polymerization of Acrylamides by Chiral ansa- Metallocenium Alkyl and Ester Enolate Cations Wesley R. Mariott and Eugene Y.-X. Chen* Contribution from the Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872 Table of Contents 1. Experimental procedures p.2 p.4 2. Figure 1. 1 H NMR spectra of isotactic PDMAA by cation 1 and atactic p.5 PDMAA by neutral rac-(ebi)zrme 2. 3. Figure 2. 13 C NMR spectrum (D 2 O, 80 ºC) of highly isotactic PDMAA p.5 by cation 3. 4. Figure 3. GPC trace of PDMAA by cation 3. p.6 5. Figure 4. DSC trace of PDMAA by cation 1/galvinoxyl. p.6 6. Figure 5. TGA trace of PDMAA by cation 1. p.7 7. Figure 6. Derivative plot of the TGA trace of PDMAA by cation 1. p.7 8. References p.8 S1
Materials and Methods. All syntheses and manipulations of air- and moisture-sensitive materials were carried out in flamed Schlenk-type glassware on a dual-manifold Schlenk line, on a high-vacuum line (10-5 to 10-7 Torr), or in an argon-filled glovebox (< 1.0 ppm oxygen and moisture). HPLC grade organic solvents were first degassed by sparging with nitrogen during the filling of the solvent reservoir and then dried by passage through activated alumina (for THF and methylene chloride) followed by passage through Q-5 supported copper catalyst (for hexanes and toluene) in stainless steel columns prior to use. Toluene used for polymerizations was further dried over sodium/potassium alloy and filtered before use. CDCl 3 was dried over activated Davison 4 Å molecular sieves. NMR spectra were recorded on either a Varian Inova 400 (FT 400 MHz, 1 H; 100 MHz, 13 C) or a Varian Inova 300 (FT 300 MHz, 1 H) spectrometer. N,N-Dimethylacrylamide (DMAA) was purchased from TCI America; it was first degassed, dried over CaH 2 overnight, and then vacuum distilled. The purified monomer was stored in a 30 C freezer inside the glovebox over activated Davison 4 Å molecular sieves. Tris(pentafluorophenyl)borane, B(C 6 F 5 ) 3, was obtained as a research gift from Boulder Scientific Company and further purified by recrystallization from hexanes at 30 ºC. Tris(pentafluorophenyl)alane Al(C 6 F 5 ) 3, 1 rac-(ebi)zrme 2 (EBI = C 2 H 4 (Ind) 2 ), 2 rac- (EBI)ZrMe + MeM(C 6 F 5 ) - 3 (M = B, 1; M = Al, 2), 3,4 and rac-(ebi)zr + (THF)[OC(O i Pr)=CMe 2 ] [MeB(C 6 F 5 ) 3 ] - (3) 4 were prepared according to literature procedures. Polymerization Procedures. All polymerizations were carried out in 30-mL glass reactors inside an argon-filled glovebox at ambient temperature. In a typical procedure the initiator (24.3 µmol) was dissolved in 5 ml of toluene or methylene chloride. For polymerizations in the presence of the radical scavenger, the initiator (24.3 µmol) and S2
galvinoxyl (2,6-di-tert-butyl-α-(3,5-di-tert-butyl-4-oxo-2,5-cyclohexadien-1-ylidene)-ptolyloxy, 20.5 mg, 48.5 µmol) were dissolved in 5 ml of toluene or methylene chloride. DMAA (1.00 ml, 9.70 mmol) was added to the solution, and the reaction mixture was vigorously stirred for 2 or 24 h. After the desired time interval, the reactor was removed from the glovebox, and the reaction was quenched by the addition of 5 ml of 5% HCl-acidfied methanol. The quenched mixture was precipitated into 100 ml of diethyl ether and stirred for 30 min, and the solvent was decanted off. An additional 75 ml of diethyl ether was used to wash the polymer and then decanted. The poly(n,n-dimethylacrylamide) (PDMAA) product was obtained as a sticky solid and dried in a vacuum oven at 50 C overnight to a constant weight. The polymer was dissolved in minimum methylene chloride, precipitated into 10-fold excess of diethyl ether, stirred for 30 min., filtered, washed with diethyl ether, and dried in a vacuum oven at 50 C for 48 h to a constant weight. The PDMAA polymers obtained are white fibrous materials. Characterization of PDMAA Samples. Powder X-ray diffraction (XRD) analyses were performed on powder samples with a Scintag X2 Advanced Diffraction System using Cu Kα (λ = 1.5418 Å) radiation and a Peltier detector on the diffracted beam side. In all cases measurements were performed with a step size of 0.02 with 1.0 second per step. Peak fittings were done using the Split-Pearson VII function using DMNST version 1.37 software. 5 When the annealing treatment was applied, the powdered polymer sample was clamped between two foil covered glass slides and placed in an oven at 140 C for ~60 h. Glass transition and melting transition temperatures (T g and T m ) of the polymers were measured by differential scanning calorimetry (DSC) on a DSC 2920 (TA Instruments). S3
Samples were first heated to 180 C at 20 C/min, equilibrated at this temperature for 4 min, and then cooled to 0 C at 10 C/min. After being held at this temperature for 4 min, the samples were reheated to 360 C at 10 C/min. All T g and T m values were obtained from the second scan, after removing the thermal history. Maximum rate decomposition temperatures (T max ) and decomposition onset temperatures (T onset ) were measured by thermogravimetric analysis (TGA) on a TGA 2950 (TA Instruments). All samples were heated from ambient temperature to 600 C at a rate of 10 C/min. Values for T max were obtained from derivative (wt%/ C) vs. temperature ( C) plots, while T onset values were obtained from wt% vs. temperature ( C) plots. Gel permeation chromatography (GPC) analyses of the polymers was carried out at 40 ºC and a flow rate of 1.0 ml/min, with CHCl 3 as the eluent, on a Waters University 1500 GPC instrument that was calibrated using 10 PMMA standards. Chromatograms were processed with Waters Empower software (2002); number-average molecular weight and polydispersity of polymers were given relative to PMMA standards. 1 H NMR spectra, for the analysis of PDMAA m/r dyads, and 13 C NMR spectra, for the analysis of PDMAA mm/rr+mr triads, were recorded in CDCl 3 at 50 C and in D 2 O at 80 C, respectively, and analyzed according to the literature. 6 Chemical shifts for 1 H and 13 C NMR spectra in CDCl 3 were referenced to internal solvent resonances and are reported as parts per million relative to tetramethylsilane, whereas the Chemical shifts for 13 C NMR spectra in D 2 O were referenced to external carbonyl carbon [mm] triad resonances previously measured in CDCl 3. S4
a (mm) trans a (mm) cis c b H n O a (trans) N a (cis) b (mm) c (m) c (m) isotactic PDMAA by cation 1 (entry 4) atactic PDMAA by rac-ebizrme 2 (entry 1) 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 PPM Figure 1. 1 H NMR spectra (CDCl 3, 50 ºC) of isotactic PDMAA by cation 1 (top: entry 4, Table 1) and atactic PDMAA by neutral rac-ebizrme 2 (bottom: entry 1, Table 1). d (mm) a (mm) trans b c b m H d O H a N N (trans) a (cis) n O c (m) a (mm) cis 176 175 174 173 36 35 34 33 32 Figure 2. 13 C NMR spectrum (D 2 O, 80 ºC) of highly isotactic PDMAA by cation 3 ([mm] > 99%, entry 10, Table 1). S5
0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 Retention Time (min) Figure 3. GPC trace of highly isotactic PDMAA by cation 3 (M n = 9.27 10 4, PDI = 1.07; entry 10, Table 1). 0.0-0.2 Heat Flow (W/g) -0.4-0.6-0.8 268 C -1.0-1.2 316 C 50 150 250 350 Temperature ( C) Figure 4. DSC trace of highly isotactic PDMAA by cation 1/galvinoxyl (T c = 268 C, T m = 316 C; entry 9, Table 1). S6
100 403 C 80 Weight (%) 60 40 20 441 C 0 100 200 300 400 500 Temperature ( C) Figure 5. TGA trace of highly isotactic PDMAA by cation 1 (T initial = 403 C, T end = 441 C; entry 4, Table 1). 3.0 2.5 Deriv. Weight (%/ C) 2.0 1.5 1.0 0.5 100 200 300 400 500 600 Temperature ( C) Figure 6. Derivative plot of the TGA trace of highly isotactic PDMAA by cation 1 (T max = 430 C; entry 4, Table 1). S7
References 1. (a) Feng, S.; Roof, G. R.; Chen, E. Y.-X. Organometallics 2002, 21, 832 839. (b) Biagini, P.; Lugli, G.; Abis, L.; Andreussi, P. U.S. Pat. 5,602269, 1997. 2. Balboni, D.; Camurati, I.; Prini, G.; Resconi, L.; Galli, S.; Mercandelli, P.; Sironi, A. Inorg. Chem. 2001, 40, 6588 6597. 3. Chen, E. Y.-X.; Kruper, W. J.; Roof, G.; Wilson, D. R. J. Am. Chem. Soc. 2001, 123, 745 746. 4. Bolig, A. D.; Chen, E. Y.-X. J. Am. Chem. Soc. 2004, 126, 4897 4906. 5. DMNST Software Manual: Version 1.37; Scintag Incorporated: Cupertino, CA, 1999. 6. (a) Lutz, J.-F.; Neugebauer, D.; Matyjaszewski, K. J. Am. Chem. Soc. 2003, 125, 6986 6993. (b) Kobayashi, M.; Okuyama, S.; Ishizone, T.; Nakahama, S. Macromolecules 1999, 32, 6466 6477. (c) Xie, X.; Hogen-Esch, T. E. Macromolecules 1996, 29, 1746 1752. (d) Bulai, A.; Jimeno, M. L.; de Queiroz, A.- A. A.; Gallardo, A.; Roman, J. S. Macromolecules 1996, 29, 3240 3246. (e) Huang, S. S.; McGrath, J. E. Polym. Prepr. (Am. Chem. Soc. Div. Polym. Chem.) 1983, 24, 138 140. (f) Gia, H.; McGrath, J. E. Polym. Bull. 1980, 2, 837 840. S8