Photoreduction of Carbon Dioxide to Carbon Monoxide with Hydrogen Catalyzed by a Rhenium(I)phenanthroline-Polyoxometalate Hybrid Complex

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1 Photoreduction of Carbon Dioxide to Carbon Monoxide with Hydrogen Catalyzed by a Rhenium(I)phenanthroline-Polyoxometalate Hybrid Complex Jessica Ettedgui, Yael Diskin-Posner, Lev Weiner and Ronny Neumann Supporting Information General Methods, Materials and Instrumentation All the chemicals and solvents were purchased commercially and used without further purification. The IR spectra were measured on a Nicolet 6700 FTIR; solid samples were prepared as ~3-5 wt % KBr based pellets. Elemental analyses (C, H, N) were performed on a CHN elemental analyzer (FlashEA 1112, Eager 300 Software). The 1 H, 13 C, 31 P NMR spectra were measured on a Bruker Avance DPX 500 spectrometer. Mass spectra were measured on a Micromass Platform LCZ 4000 (Manchester, UK) utilizing the electron spray ionization method. Reactions were carried out in 5 ml Pyrex pressure tubes. CO 2 (>99.99% purity) was purchased from Gordon Gas. Methods: GC and GC MS were carried out on HP 6890 (flame ionization detector and thermal conductivity detector (TCD)) and HP 5973 (MS detector) instruments equipped with a 30 m column (Restek 5MS, 0.32 mm internal diameter) with a 5% phenylmethylsilicone coating (0.25 mm) and helium as carrier gas. The gaseous reaction products including CO were analyzed by GC TCD with a Carbonplot capillary column (J&W Scientific). Synthesis 1,10-Phenanthroline-5,6-dione was prepared according to literature method (W. Paw and R. Eisenberg Inorg. Chem. 1997, 36, ). An ice-cold mixture of concentrated H 2 SO 4 (10 ml) and HNO 3 (5 ml) was added to 1 g of 1,10-phenanthroline (5.5 mmol) and 1 g of KBr (8.4 mmol). The mixture was heated at reflux for 3 h. The hot yellow solution was poured over 500 ml of ice and neutralized carefully with sodium hydroxide until neutral to slightly acidic ph. Extraction with CHCl 3 followed by drying with Na 2 SO 4 and removal of solvent gave 1.5 g (96%) of 1,10- phenanthroline-5,6-dione. This product is quite pure but was purified further by crystallization from ethanol. 1 H NMR 500 MHz (CDCl 3 ): δ 9.11 (dd, 2H), δ 8.48 (dd, 2H), δ 7.58 (dd, 2H). 1,10-Phenanthroline-5,6-diol was prepared according to the literature method (J.-Z. Wu, H. Li, J.- G. Zhang, J.-H. Xu, Inorg. Chem. Comm. 2002, 5, 71 75). 1,10-phenanthroline-5,6-dione (0.5 g, 2.4 mmol) and hydrazine sulfate (1.1 g, 8.46 mmol) were mixed in water (15 ml) and kept in a boiling water bath for about 2 min, until the vigorous evolution of the gas had ceased. Upon cooling the yellow solid was removed and washed with ethanol thoroughly to yield 0.42 g (83%) 1,10- phenanthroline-5,6-diol. 1 H NMR 500 MHz (DMSO-d 6 ): δ (s, 2H) δ 9.45 (d, 2H), δ 8.92 (dd, S1

2 2H), δ 8.57 (dd, 2H), δ 7.73 (dd, 2H). 15-Crown-5 ether 5,6-phenanthroline (L). Sodium hydride (0.266 g, mmol of 60% mineral oil dispersion) was added to a solution of 1,10-phenanthroline-5,6-diol (0.7 g, 3.30 mmol ) in dry DMF (22 ml) under Ar, and stirred for 10 min. A solution of tetraethyleneglycol-ditosylate (1.685 g, mmol) in dry DMF (20 ml) was added slowly. The mixture was stirred at 80 C overnight. The solvent was removed and water (70 ml) was added to the crude product. The suspension was extracted 3 times with small portions of CH 2 Cl 2 that were combined and dried over Mg 2 SO 4 before evaporation to dryness in vacuum to give a brown oil. The crude product was dissolved in CH 2 Cl 2 and stirred with activated carbon at 40 C. The solution was purified through basic alumina to provide a 30 % yield of yellow crystals. 1 H NMR 500 MHz (CDCl 3 ): δ 9.15 (dd, 2H), δ 8.59 (dd, 2H), δ 7.68 (q, 2H), δ 4.45 (t, 2H), δ 4.07 (t, 2H), δ 3.79 (m, 4H). Elemental analysis - calculated for C 20 H 22 N 2 O 5 : C %; H 5.99 %; N 7.56 %. Found: C %; H 6.06 %; N 7.47 %. Re I (L)(CO) 3 (Cl). Re(CO) 5 Cl (15 mg, 0.13 mmol) and an excess of L (30 mg, 0.27mmol), were mixed in 1.5 ml of xylene and heated to reflux. The resulting solid was separated by filtration and washed with xylene. Purification was achieved by recrystallization from CH 2 Cl 2 by addition of diethyl ether to yield 75%. 1 H NMR 300 MHz (CDCl 3 ): δ 9.37 (dd, 2H), δ 8.80 (dd, 2H), δ 7.83 (q, 2H), δ 4.55 (t, 2H), δ 4.09 (t, 2H), δ 3.81 (m, 4H). 1 H NMR 300 MHz (CD 3 CN): δ (dd, 2H), δ (dd, 2H), δ (dd, 2H), δ (m, 2H), δ (t, 2H), δ (m, 4H). Elemental analysis - calculated for C 23 H 22 N 2 O 8 ReCl: C %; H 3.28 %; N 4.14 %. Found: C %; H 3.35 %; N 4.29 %. Re I (L)(CO) 3 (AcCN) MHPW 12 O 40. A solution of Re I (L)(CO) 3 (Cl) (7 mg, 9.8 µmol) in 4 ml acetonitrile was added to a solution of H 3 PW 12 O 40 (28.5 mg, 9.8 µmol) in 2 ml acetonitrile and stirred for 6 h. AcCN was gently removed and the solid Re I (L)(CO) 3 (AcCN) MHPW 12 O 40 obtained was washed with CHCl 3 and dried under vacuum. 1 H NMR 500 MHz (CD 3 CN): δ 9.31 (dd, 2H), δ 9.01 (dd, 2H), δ 8.03 (dd, 2H), δ 4.52 (m, 4H), δ 4.05 (t, 4H), δ 3.74 (m, 8H), δ 2.00 (s, 3H). Elemental analysis - calculated for C 25 H 28 N 3 O 48 RePW 12 : C 8.43 %; H 0.79 %; N %. Found: C 8.11 %; H 0.91 %; N 1.02%. ESI-MS (positive ion) m/z = 680 (55), 681 (15), 682 (100), 683 (27). ESI-MS (negative ion) cluster at m/z and for PW 12 O 40 for z = 3 and z = 2, respectively. See also figures below. 31 P NMR ppm. X-ray quality crystals were grown by dissolving 3 mg of S2

Re I (15-crown-5-phen)(CO) 3 (Cl) (5.17 µmol; 1 equivalent) in a minimum of acetonitrile a drop of chloroform was added in order to completely dissolve the rhenium complex. Then a solution of 22.

3 Re I (15-crown-5-phen)(CO) 3 (Cl) (5.17 µmol; 1 equivalent) in a minimum of acetonitrile a drop of chloroform was added in order to completely dissolve the rhenium complex. Then a solution of mg of H 3 PW 12 O 40 (7.76 µmol; 1.5 equivalent) in acetonitrile is gently added on the top of the rhenium solution in order to allow the slow diffusion of the polyoxometalate. Crystals grew from the mixture left open to air, overnight. Two kinds of crystals grew but only one of them could be collected, the other one was too fragile to take out of the solution. For 1 H NMR, 13 C NMR and IR see figures below. Crystal data for Re I (L)(CO) 3 (CH 3 CN) 2 -NaHPW 12 O 40 3CH 3 CN 3.5H 2 O were measured at 120(2) K on a Bruker Kappa ApexII CCD diffractometer (λ(mo-kα) = Å) with a graphite monochromator. The data were processed with APEX-II. Structures were solved by the AUTOSOLVE module and refined with full-matrix least-squares refinement based on F 2 with SHELX-97; 932 parameters with 18 restraints. All non-hydrogen atoms were refined anisotropically, using weighted full-matrix least-squares on F 2. Crystal data collection and refinement parameters are given in Table S1. Complete details can be found in the accompanying cif file. Table S1. Crystal data collection and refinement parameters for Re I (L)(CO) 3 (CH 3 CN) 2 - NaHPW 12 O 40 3CH 3 CN 3.5H 2 O. empirical formula C 66 H 87 N 14 Na 2 O 103 P 2 Re 2 W 24 V, Å (14) formula weight Z 1 crystal system triclinic d calc, mg/cm space group P-1 µ, mm a, Å (3) reflections b, Å (3) unique reflections c, Å (5) R int α, deg (10) R [I>2σ] R 1 = wr 2 = β, deg (10) R all data R 1 = wr 2 = γ, deg (10) goodness of fit R 1 = Σ F 0 - F c /Σ F 0 ; wr 2 = {Σ[w(F 0 2 -F c 2 ) 2 ]/Σw(F 0 2 ) 2 ]} 1/2 S3

4 Figure S1. The ball and stick structure of Re I (L)(CO) 3 (CH 3 CN) 2 -NaHPW 12 O 40 3CH 3 CN 3.5H 2 O showing the 1 D polymeric chain. H atoms and solvent molecules are not shown. C-black, N-blue, O-red, P-purple, Na-yellow, Re-green, W-gray. Figure S2. 1 H NMR 500 MHz (CD 3 CN) of Re I (L)(CO) 3 (AcCN)-MHPW 12 O 40. S4

5 Figure S3. 1 C NMR 126 MHz (CD 3 CN) of Re I (L)(CO) 3 (AcCN)-MHPW 12 O 40. S5

6 Figure S4. IR of Re I (L)(CO) 3 (AcCN)-MHPW 12 O 40 (red, middle), H 3 PW 12 O 40 (black, top) and Re I (L)(CO) 3 Cl (bottom, green) S6

7 Figure S5. ESI-MS of Re I (L)(CO) 3 (AcCN) MHPW 12 O 40 in positive (top) and negative (bottom) ion mode. S7

8 Figure S6. 1 H NMR 500 MHz (CD 3 CON(CD 3 ) 2 ) of Re I (L)(CO) 3 (AcCN)-MHPW 12 O 40 before the reaction and after 16 h: Re I (L)(CO) 3 (AcCN)-MHPW 12 O 40 (5.0 µmol), DMA (0.5 ml), 20 µg Pt/C, CO 2 (1 bar), H 2 (2 bar), 20 C, under irradiation with a 150 W Xe lamp. Figure S7. UV-vis spectra of Re I (L)(CO) 3 (Solv)-MHPW 12 O 40 in DMA (2.8 x 10 5 M) (black); Re I (L)(CO) 3 (Solv)-MHPW 12 O 40 in DMA (2.8 x 10 5 M) & 2 µg Pt/C, H 2 (1 bar) for 1 h (green); and Re I (L)(CO) 3 (AcCN)-MHPW 12 O 40 in DMA (2.8 x 10 5 M) & 2 µg Pt/C, CO 2 (1 bar), H 2 (1 bar), 20 C, under irradiation with a 150 W Xe lamp for 16 h. At > 380 nm: Re I (L)(CO) 3 (Solv)-MHPW 12 O 40 before reaction - λ max (log ε) = 400 (3.65), 540 (2.83); Re I (L)(CO) 3 (Solv)-MHPW 12 O 40 after reduction with H 2 - λ max (log ε) = 486 (3.03); 656 (3.21) S8

9 Figure S8. IR spectrum of Re I (L)(CO) 3 (CH 3 CN)-MHPW 12 O 40 after exposure to reaction conditions (Re I (L)(CO) 3 (CH 3 CN)-MHPW 12 O 40 (0.5 µmol), DMA (0.5 ml), 20 µg Pt/C, CO 2 (1 bar), H 2 (2 bar), 20 C, 14 h under irradiation with a 150 W Xe lamp). S9

Supporting Information. Metal-coordination-driven Mixed Ligand Binding in Supramolecular Bisporphyrin Tweezers

Supporting Information. Metal-coordination-driven Mixed Ligand Binding in Supramolecular Bisporphyrin Tweezers Electronic Supplementary Material (ESI) for ChemComm. This journal is The Royal Society of Chemistry 2015 Supporting Information Metal-coordination-driven Mixed Ligand Binding in Supramolecular Bisporphyrin