Supporting information Migration Insertion Polymerization (MIP) of Cyclcopentadienyldicarbonyldiphenylphosphinopropyliron (FpP): A New Concept for Main Chain Metal-Containing Polymers (MCPs) Xiaosong Wang,* Kai Cao, Yibo Liu, Brian Tsang, and Sean Liew Department of Chemistry and Waterloo Institute of Nanotechnology, University of Waterloo, 200 University Ave, Waterloo, Canada N2L 3G1 Experimental Materials and Instrumentation All experiments were performed under an atmosphere of dry nitrogen using standard Schlenk techniques/glovebox unless otherwise indicated. THF was freshly distilled under nitrogen from Na/benzophenone. Hexane and DCM were degassed with dry nitrogen before use and benzene was distilled from CaH 2 before use. Sodium (Na), 1-bromo-3-chloropropane (Br(CH 2 ) 3 Cl), 1- bromodencane (CH 3 (CH 2 ) 9 Br), potassium (K), and cyclopentadienyl iron dicarbonyl dimer (Fp 2 ) were purchased from Sigma-Aldrich. Chlorodiphenylphosphine (Ph 2 PCl) was purchased from Tokyo Chemical Industry (TCI). Benzophenone was purchased from Fisher Scientific. All chemicals were used as received unless otherwise indicated. Molecular weights and molecular weight distributions, M w /M n, were characterized by GPC at room temperature. THF was used as eluent at a flow rate of 1.0 ml/min on a system consisting of a Waters 510 HPLC pump, Jordi DVB Mixed-bed Linear columns (500 mm 10 mm, molecular weight range of 10 2-10 7 ), and a Waters 410 differential refractometer detector. Data were analyzed with ASTRA v4.70 software package and molecular weight was obtained by universal calibration methods. 1 H, 31 P, 13 C NMR and 1 H- 1 H COSY, and 1 H- 13 C HMQC 2D NMR spectra were obtained on a Bruker-300 (300 MHz) spectrometer at ambient temperature using appropriate solvents. NMR samples were prepared under dry nitrogen atmosphere, unless otherwise indicated. Transmission electron microscopy (TEM) images were taken on a transmission electron microscope (Philips CM10) with an acceleration voltage of 60 kv. TEM samples were prepared by placing a drop of solution onto a carbon-coated copper grid. Excess solution was removed by filter paper followed by drying under ambient conditions. The specimens were observed without staining S1
due to the presence of iron elements. Fourier transform infrared spectroscopy (FTIR) spectra were recorded as Nujol mulls between KBr plates using a Perkin Elmer Spectrum RX I FTIR system. Differential scanning calorimetry (DSC) data was recorded using a DCS (Q10, TA Instruments). The samples (~ 5 mg) were enclosed in an aluminum pan with an empty aluminum pan as reference. The measurements were performed under a flow of N 2 (50 ml/min). Thermal history was removed by heating the samples from 25 o C to 150 o C (ramp: 10 o C/min), then cooling back to 50 o C (ramp: 5 o C/min). The measurement was performed by heating the samples from -50 o C to 150 o C (ramp: 10 o C/min). Thermal gravimetric analysis (TGA) was carried out on a TGA Q50 at a heating rate of 10 o C/min. Samples were dried under vacuum at 50 o C overnight. Dynamic light scattering (DLS) was carried out at 25 o C on Zetasizer Nano90, Malevern Positive ion electrospray (ESI) experiments were performed with a Waters QTOF Ultima Global mass spectrometer. Samples were infused at 1 µl/min in dry CH 3 CN for +ve ion. The operating conditions were: source temperature = 80 o C, capillary voltage = 2.5 kv, cone voltage = 60-160 V and the experiments were performed with argon as collision gas and collision energy of 15 ev. Synthesis of cyclopentadienyl dicarbonyliron potassium (FpK) FpK was prepared according to literature. 1 Synthesis of sodium diphenylphosphide (Ph 2 PNa). Ph 2 PNa was prepared by heating sodium and ClPPh 2 at 40 o C for three days. The resulting orange solution was directly used for further reactions. 31 P NMR (THF): -23 ppm. Synthesis of 3-chloropropyldiphenylphosphine (Ph 2 PCH 2 CH 2 CH 2 Cl). A 250 ml Schlenk flask was charged with a solution of BrCH 2 CH 2 CH 2 Cl (7.87 g, 5.0 10-2 mol) in dry THF (50 ml). To this solution, Ph 2 PNa (0.5 M in THF solution) (60 ml, 3.0 10-2 mol) was added dropwise at 0 C under stirring. The mixture was allowed to warm to rt and left stirring overnight. Afterwards, the mixture was heated at 60 C for ca. 2 h under vacuum. The residue was dissolved using degassed hexane and filtered through a plug of silica gel. The solvent was subsequently removed under vacuum at rt, yielding a colorless oil (5.52 g, 70 % yield). 1 H NMR (CDCl 3 ): 7.45 ppm and 7.35 ppm (d, 10 H, aromatic protons), 3.60 ppm (t, 2H, CH 2 Cl), 2.20 ppm (t, 2H, CH 2 P) and 1.92 (m, CH 2 CH 2 CH 2 ). 31 P NMR: -14.7 ppm. Synthesis of cyclopentadienyl dicarbonyldiphenylphosphinopropyliron (FpP) A solution of Ph 2 PCH 2 CH 2 CH 2 Cl (1.44 g, 5.5 10-3 mol) in THF (5 ml) was added to an orange suspension of FpK (1.00 g, 4.6 10-3 mol) in THF (20 ml) at 0 C under stirring. The mixture was stirred at rt for 1.5 h. Afterwards, the solution was filtered with a plug of celite. The reddish brown filtrate was collected and the solvent was removed under vacuum, resulting in dark reddish brown oil. This oil was dissolved in a minimum of hexane/dcm (3.5: 1, v/v) and chromatographed on a silica gel column. A bright yellow fraction was collected. The product was characterized as soon as the solvents were removed (FpP undergoes migration insertion reactions at room temperature, but the reaction rate is very slow). 1 H NMR (DMSO-d 6 ): 7.35 (t, 4 H, ortho- C 6 H 5 ), 7.32 ppm (m, 6 H, S2
para, meta-c 6 H 5 ), 4.87 ppm (s, 5H, C 5 H 5 ), 2.07 ppm (2H, PCH 2 ), 1.46 ppm (4H, FeCH 2 CH 2 ). 1 H NMR (C 6 D 6 ): 7.61 ppm (t, 4 H, ortho- C 6 H 5 ), 7.20 (m, 6 H, para, meta-c 6 H 5 ), 4.03 ppm (s, 5H, C 5 H 5 ), 2.25 ppm (t, 2H, PCH 2 ), 1.80 ppm (m, 2H, CH 2 CH 2 CH 2 ), 1.64 ppm (t, 2H, Fe-CH 2 ). 31 P NMR (DMSO-d 6 ): -14.6 ppm. 31 P NMR (C 6 D 6 ): -14.4 ppm. 13 C NMR (DMSO-d6): 5 ppm (FpCH 2 ), 33 ppm (CH 2 P(Ph) 2 ), 34 ppm (CH 2 CH 2 P(Ph) 2 ), 87 ppm (C 5 H 4 ), 129 ppm, 132 ppm, 139 ppm (Ph), 218 ppm (FeC O). FTIR (Nujol mull): 2004 cm -1 and 1952 cm -1 (terminal CO stretching). ESI-MS: 405 (M+H + ). UV-Vis: one absorption peak was observed at the wavelength of 346 nm. Polymerization of FpP The polymerization of FpP was carried out in bulk at 70 o C. After the polymerization, the crude product was dissolved in a minimum of THF, followed by precipitating in hexane via cannula. The precipitate was collected by filtration and dried under vacuum at room temperature overnight. The resulting polymer is bright yellow powder. 1 H NMR (DMSO-d 6 ): 7.8-7.1 ppm (10H, C 6 H 5 ), 4.4-4.2 ppm (5H, C 5 H 5 ), 2.78-2.60 ppm (1H, COCH 2 ), 2.47-2.17 ppm (1H, COCH 2 ), 2.13-1.89 ppm (2H, CH 2 CH 2 CH 2 ), and 1.32-0.74 ppm (2H, CH 2 PFe). 13 C NMR (DMSO-d 6 ) 20 ppm (CH 2 P(Ph) 2 ), 28 ppm (CH 2 CH 2 CH 2 ), 66 ppm (COCH 2 CH 2 CH 2 ), 86 ppm, 84 ppm (C 5 H 4 ), 127 ppm, 128ppm, 129 ppm, 130 ppm, 132 ppm (Ph), 220 ppm (FeC O), 274 ppm (FeCOCH 2 ) 31 P NMR (CDCl 3 ): 73.4 ppm (backbone PFe), 72.3 ppm (end group PFe), and -13.6 ppm (end group PPh 2 ). FTIR: 1910 cm - 1 (terminal CO stretching), 1600 cm -1 (ketonic CO stretching). Synthesis of oligoethylene functionalized PFpP through migration insertion reaction of PFpP end group. Oligoethylene diphenylphosphine (21.2 mg, 0.065 mmol) was added to a solution of PFpP (86.3 mg, 0.013mmol, M n = 6642 g/mol, PDI=1.09) in 12 ml THF. The solution was refluxed at 80 o C for 3 days. Afterwards the solution was concentrated and precipitated into hexane. The precipitate was collected by centrifugation and dried under vacuum overnight at rt. 1 HNMR (DMSO-d 6 ): 7.8-7.1 ppm (10H, C 6 H 5 ), 4.4-4.2 ppm (5H, C 5 H 5 ), 1.3-0.9 ppm (21H C 9 H 18 +3H CH 3 ). 31 P NMR (DCM): 73.5 ppm (coordinated phosphine), -15 ppm (phosphine end group). Micelliation of PFpP amphiphiliers. Oligoethylene functionalized PFpP (2 mg) was dissolved in THF (2 ml) and was stirred for 15 minutes. Afterwards, hexane (12 ml) was added drop wise to the solution. The mixture was used for DLS and TEM analysis. S3
Figure S1. IR spectra for (a) PFpP and (b) FpP Figure S2 1 H- 1 H COSY and 1 H- 13 C HMQC 2D NMR spectra of FpP in DMSO-d 6 Figure S2 shows that the chemical signals of the protons adjacent to the metal (CH 2 -Fe), and the protons belonging to the middle carbon of the propane space (CH 2 -CH 2 -CH 2 -Fe) are overlapped. The integration ratio between the signals at 2.10 ppm and 1.46 ppm is 1:2, which is in agreement with the structure of FpP. S4
Figure S3 1 H- 1 H COSY 2D NMR spectrum of FpP in C 6 D 6. Figure S3 shows the two previously overlapped signals are well separated in C 6 D 6. The triplet peak at 2.25 ppm is assigned to the proton next to the phosphorous, the multiplet peaks at 1.80 ppm is caused by the middle CH 2 protons in the propane spacer, and the CH 2 proton next to Fe is observed as a triplet peak at 1.64 ppm. The integration ratio is 1 : 1 : 1.. Figure S4 Uncoordinated phosphine signals in 31 P NMR as a function of PFpP MIR reaction time in the presence of one equivalent of ClCH 2 CH 2 CH 2 PPh 2 at 50 o C PFpP (DP = 6 characterized by NMR) was dissolved in THF (20 mg/3ml) and heated at 50 o C to induce MIR in the presence of one equivalent of ClCH 2 CH 2 CH 2 PPh 2. The relative reactivity of PFpP phosphine end group and ClCH 2 CH 2 CH 2 PPh 2 was compared by time-resolved resonance intensities corresponding to the respective phosphine in 31 P NMR. In Figure S4, small molecule shows high reactivity relative to PFpP phosphine end group due to a lessened steric effect. S5
Figure S5. 13 C NMR spectrum of (a) PFpP and (b) FpP in DMSO-d 6. The appearance of the signal at 274 ppm in the 13 C NMR spectrum for PFpP indicates that a migration insertion occurred. Figure S6. 1 H- 13 C HMQC 2D NMR of PFpP Figure S6 shows the 1 H- 13 C HMQC 2D NMR of PFpP. A correlation map between the coupled spins suggested that the protons with resonance peaks at 2.8 and 2.3 ppm are derived from the same carbon C(O)CH 2. Therefore these two protons are diastereotopic. S6
Figure S7. 1 HNMR spectra for PFpP homopolymers and oligoethylene functionalized PFpP amphiphiles in DMSO-d 6 As shown in Figure S7, the signal at 4.7 ppm due to the Fp end group has disappeared, indicating that phosphine assisted MIR has occurred. PFpP was end functionalized with oligoethylene, leading to an enhanced intensity for the signal at 0.9-1.6 ppm which also leads to broader peaks due to the poor solubility of oligoethylene in DMSO. Figure S8. TEM image of the aggregates self-assembled from oligoethylene phosphine functionalized polymers in hexane/thf (85/15 by volume). Scale bar = 1 µm. (Inset: DLS analysis). The oligoethylene functionalized PFpP amphiphiles self-assembled into spherical aggregates by adding hexane into the THF solution (Figure S8), while the PFpP blocks were precipitated under the same condition. This comparison verified the formation of end functionalized PFpP amphiphiles. The larger size of the particles (R h = 245 nm) may suggest the formation of compound micelles due S7
to short oligoethylene chains. Solution behavior of FpP Solution behavour of FpP was tested in a N 2 atmosphere at room temperature in nine different solvents, including acetonitrile, benzene, CDCl 3, DCM, DMF, DMSO, hexane, THF, toluene. The monomer concentration in each solvent was 0.01 g/ml. The color for all the solutions was initially bright yellow and gradually turned orange. On the 7 th day, the solutions became darker compared to those on the 3 rd day. No precipitation was observed in all the cases (see Figure S9 as an example). As shown in 31 P NMR (Figure S9), fresh sample shows a single peak at -14.7 ppm, which is attributed to the monomer. 31 P NMR spectrum for the sample on the 7 th day (Figure S9) shows that most monomers converted into a five-member ring with 31 PNMR signal at 109 ppm. Similar results are obtained in the cases of acetonitrile, benzene, CDCl 3, DCM, DMF, hexane, THF and toluene, suggesting intramolecular cyclic reactions are favored in diluted solvents. Figure S9. Color change of the monomer in THF solution (top) and 31 P NMR spectra of fresh sample and sample incubated for 7 days. S8
Data File: 2012-02-13_16;37;54_Hui_02.vdt Method: Narrow PS standard-0000.vcm 27.21 26.81 26.41 Viscom eter - IP R esponse (m V ) 26.01 25.61 25.21 24.81 RI detector Viscometer detector 24.41 24.01 Light scattering detector 23.61 23.22 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00 50.00 Retention Volume (ml) Figure S10. Representative GPC traces for PFpP: M w = 13090, M n = 9870 and PDI = 1.33. Figure S11. UV-Vis spectrum of FpP monomers in THF S9
The ion at m/z 405 is interpreted as the [M+H] + ion from the indicated iron complex. Experimental and theoretical isotopic distributions are in good agreement. Experimental Isotopic Distribution for C 22 H 22 O 2 P 1 Fe 1 Fe monomer mw=404 +ESI in dry MeCN low CE&CV JAN18YL1 15 (0.545) Cm (15:40) 405.0796 100 18-Jan-2013 1: TOF MS ES+ 2.95e3 % 406.0776 403.0798 407.0992 0 m/z 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 Theoretical Isotopic Distribution for C 22 H 22 O 2 P 1 Fe 1 Fe monomer mw=404 +ESI in dry MeCN low CE&CV JAN18YL1 (0.045) Cu (0.10); Is (0.10,0.01) C22H22O2P1Fe1 100 405.0703 18-Jan-2013 1: TOF MS ES+ 7.15e12 % 406.0703 403.0781 407.0781 0 398 399 400 401 402 403 404 405 406 407 408 409 410 411 mass 412 Figure S12. Experimental and theoretical isotopic distribution for FpP S10
Additional References 1. P. W. Clark, Org. Prep. Proced. Int., 1979, 11, 103-106. S11