Supporting Information. A Robust Ni(II) α-diimine Catalyst for High Temperature Ethylene Polymerization

Transcription

1 Supporting Information A Robust Ni(II) α-diimine Catalyst for High Temperature Ethylene Polymerization Jennifer L. Rhinehart, Lauren A. Brown and Brian K. Long* Univeristy of Tennessee, Department of Chemistry, Knoxville, TN 37996, United States Long@utk.edu Contents General Methods and Materials Syntheti Proedures Ethylene polymerization results for 2a Polyethylene branhing data for high-temp polymerizations using 2b Representative polyethylene NMR spetra S2 S2 S3 S3 S4-S7 S1

2 General Methods and Materials. All reations were performed under a dry nitrogen atmosphere using an MBraun UniLab drybox or standard Shlenk tehniques unless otherwise noted. Solvents were dried on an Innovative Tehnologies PureSolv Solvent Purifiation System and degassed by three freeze-pumpthaw yles. Toluene was passed through alumina and opper olumns. CD 2 Cl 2 was dried over ativated moleular sieves (4Å) and degassed by three freeze-pump-thaw yles prior to use. 2,6- bis(diphenylmethyl)-4-methylaniline and N,N -bis(2,6-dibenzhydryl-4-methylphenyl)ethane-1,2-diimine (1a) were prepared as previously reported. 1 PMAO-IP was purhased from Akzo Nobel. All other reagents were purhased from ommerial vendors and used without further purifiation. 1 H and 13 C NMR spetra were reorded at ambient temperature on a Varian Merury 300 MHz or Varian VNMRS 500 MHz narrow-bore broadband system. 1 H and 13 C NMR hemial shifts were referened to the residual solvent. Elemental miroanalyses were arried out by Atlanti Mirolab, In. (Norross, GA). All mass spetrometry analyses were performed using a JEOL AuTOF-D time-of-flight (TOF) mass spetrometer with a DART (diret analysis in real time) ionization soure. X-Ray diffration measurements were performed on single rystals oated with Paratone oil, mounted on a loop, and frozen under a stream of N 2 while data was olleted on a Bruker APEX diffratometer. Refletions were merged and orreted for Lorenz and polarization effets, san speed, and bakground using SAINT The struture was solved by diret methods with the aid of suessive differene Fourier maps, and were refined against all data using the SHELXTL 5.0 software pakage. All of the solvent moleules were squeezed. Gel permeation hromatography was performed at 145 C in 1,2,4-trihlorobenzene at 1.0 ml/min on a Polymer Labs GPC220 equipped with refrative index and two-angle light-sattering detetors (Preision Detetors). Weight average moleular weights (M w ) were obtained from GPC light sattering data and moleular weight distributions (M w /M n ) were obtained from GPC refrative index data relative to polystyrene standards. Number average moleular weights (M n ) were alulated using M w, obtained from light sattering, and moleular weight distributions (M w /M n ) obtained from RI. Polymer melting point transition temperatures (T m ) were measured on a TA Instruments Q1000 differential sanning alorimeter equipped with an autosampler on the seond heating yle at a heating rate of 10 C/min. Synthesis of N,N'-bis(2,6-dibenzhydryl-4-methylphenyl) butane-2,3-diimine (1b). 2,6- bis(diphenylmethyl)-4-methyl- aniline (544.9 mg, 1.23 mmol) and 2,3-butadione (52 µl, 0.59 mmol) were harged in a round bottom flask with methylene hloride (20 ml). Formi aid (10 drops) and magnesium sulfate were added and the reation heated to reflux for 3 days open to air. The reation was filtered and washed with exess methylene hloride. The purified produt was obtained by olumn hromatography. Yield 8.6% (100 mg). Rf = 0.48 (hexanes/dm, 50:50). 1 H NMR (CD 2 Cl 2, 500 MHz): δ (m, 24H), 7.06 (d, J = 7.4 Hz, 8H), 6.97 (d, J = 6.9 Hz, 8H), 6.70 (s, 4H), 5.15 (s, 4H), 2.14 (s, 6H), 1.23 (s, 6H). 13 C NMR (CDCl 3, 125 MHz): δ , , , , , , , , , , , , , 51.82, 21.50, DART (m/z)(al.): (928.48). Synthesis of NiBr 2 (ArN=CC=NAr) (Ar = 2,6 bis(diphenylmethyl)-4-methylbenzene) (2a). A solution of N,N -bis(2,6-dibenzhydryl-4-methylphenyl)ethane-1,2-diimine (99.6 mg, 0.11 mmol) in methylene hloride (5 ml) was added to nikel(ii) dibromide dimethoxyethane addut (66.0 mg, 0.21 mmol) in a Shlenk flask and stirred overnight at room temperature. The reation was filtered through a pad of elite and the solvent removed in vauo. The preatalyst was used without further purifiation. Yield 96% (107.2 mg). 1 H NMR (CD 2 Cl 2, 500 MHz): δ (s, 6H, Ar-Me), (s, 4H, CH), 7.30, 7.15, 7.04, C NMR (CD2Cl2, 125 MHz): δ , , 129.4, , , , Synthesis of NiBr 2 (ArN=C(Me)C(Me)=NAr) (Ar = 2,6 bis(diphenylmethyl)-4-methylbenzene) (2b). A solution of N,N'-bis(2,6-dibenzhydryl-4-methylphenyl)butane-2,3-diimine (239.4 mg, 0.25 mmol) in methylene hloride (5 ml) was added to a Shlenk flask ontaining nikel(ii) dibromide dimethoxyethane addut (79.1 mg, 0.25 mmol). The reation mixture was heated to 30 C and stirred for five hours. The reation was filtered through a pad of elite and layered with pentane to indue rystallization. The solvent was deanted and dried in vauo. Yield 86% (247.8 mg). 1 H NMR (CD 2 Cl 2, 500 MHz): δ (s, 6H, Ar-Me), (s, 4H, CH), (2H), 7.98 (8H), 7.02 (8H), 6.86 (4H), 6.55 (14H), 4.52 (8H), (6H, CH 3 ). 13 C NMR (CD 2 Cl 2, 125 MHz): δ , , , , , Anal. Cald for C 70 H 60 N 2 Br 2 Ni ( ): C 73.25, H 5.27, N 2.44; found C S2

3 73.55, H 5.50, N General polymerization onditions. Under an inert atmosphere, a Fisher Porter bottle was harged with nikel atalyst 2a or 2b (1.57 µmol), 100 ml of toluene, and a magneti stir bar. The bottle was sealed and plaed in an oil bath at the desired temperature. The vessel was pressurized with ethylene and allowed to equilibrate under onstant pressure for 10 minutes with stirring. PMAO-IP was injeted to initiate polymerization and stirred ontinuously for the desired time. The polymerization was quenhed via the addition of MeOH (5 ml) and the polymer was preipitated using exess aidi MeOH (5% HCl in MeOH) and dried in a vauum oven to onstant weight. Table S1. Ethylene polymerization results for atalyst 2a. Entry T rxn t (min) Yield (mg) TOF M n (h -1 ) b (g/mol) M w /M n ND ND ND e ND ND a Polymerization onditions: [2a] = 1.69 µmol, 100 ml toluene, 15 psi and 100 eq. PMAO-IP. b Turnover frequeny (TOF) = mol ethylene/(mol at*h). Determined using gel permeation hromatography at 145 C in 1,2,4-trihlorobenzene. d Determined by differential sanning alorimetry, seond heat. e Seond heating showed a bimodal melting temperature of 129 and 133 C. ND = not determined. T m d Table S2. Ethylene polymerization results for atalyst 2b (inluding branhing ontent). entry T rxn time (min) yield (mg) TOF b ( 10 3 h -1 ) M n (kg/mol) M w /M n T m d branhes per 1000 arbons e S3

4 a Polymerization onditions: [2b] = 1.57 µmol, 100 ml toluene, 100 psi ethylene and 300 eq. PMAO-IP. b TOF = mol ethylene/(mol at*h). Determined using gel permeation hromatography at 145 C in 1,2,4- trihlorobenzene. d Determined by differential sanning alorimetry, seond heat. e Determined by 1 H NMR spetrosopy. Figure S1. 1 H NMR Spetrum of polyethylene made by atalyst 2b (Table 2, Entry 4) S4

5 Figure S2. 1 H NMR Spetrum of polyethylene made by atalyst 2b (Table 2, Entry 8) S5

6 Figure S3. 1 H NMR Spetrum of polyethylene made by atalyst 2b (Table 2, Entry 12). S6

7 Figure S4. 13 C NMR Spetrum of polyethylene made by atalyst 2b (Table 2, Entry 8) (1) Berthon-Gelloz, G.; Siegler, M. A.; Spek, A. L.; Tinant, B.; Reek, J. N.; Marko, I. E. Dalton Trans 2010, 39, S7