Supporting Information

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1 Supporting Information Copyright Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, 2011 Transformation of Nickelalactones to Methyl Acrylate: On the Way to a Catalytic Conversion of Carbon Dioxide S. Y. Tina Lee, [a] Mirza Cokoja, [b] Markus Drees, [b] Yang Li, [a] Jµnos Mink, [c] Wolfgang A. Herrmann, [b] and [a, b] Fritz E. Kühn* cssc_ _sm_miscellaneous_information.pdf

2 Supporting Information Transformation of nickelalactones to methyl acrylate: On the way to a catalytic conversion of CO 2 S. Y. Tina Lee, [a] Mirza Cokoja, [b] Markus Drees, [b] Yang Li, [a] János Mink, [c] Wolfgang A. Herrmann [b] and Fritz E. Kühn [a, b] * [a] [b] [c] S.Y.T. Lee, Dr. Y. Li, Prof. Dr. F. E. Kühn Molecular Catalysis, Catalysis Research Center Technische Universität München Ernst-Otto-Fischer-Str. 1 D Garching (Germany) fritz.kuehn@ch.tum.de Dr. M. Cokoja, Dr. M. Drees, Prof. Dr. Dr. h.c. mult. W. A. Herrmann, Prof. Dr. F. E. Kühn Chair of Inorganic Chemistry, Catalysis Research Center Technische Universität München Ernst-Otto-Fischer-Str. 1 D Garching (Germany) Prof. Dr. J. Mink Research Institute of Chemical and Process Engineering University of Pannonia H-8200 Veszprém (Hungary) 1

3 1. Characterization of the starting materials Figure S1. 1 H NMR spectrum of complex 1 (400 MHz, CD 2 Cl 2, r.t.): d 0.40 (t, 2H, CH 2 ), 1.77 (t, 2H, CH 2 ), 2.27 (s, 4H, CH 2 ), 2.32 (s, 6H, CH 3 ), 2.53 (s, 6H, CH 3 ). Figure S2. ORTEP view of the structure of compound 1. Selected bond lengths (Å) and angles ( ): Ni(1) O(1) 1.854(2), Ni(1) C(3) 1.925(2), Ni(1) N(1) 1.960(2), Ni(1) N(2) 2.032(2), N(1) Ni(1) O(1) (8), N(2) Ni(1) C(3) 175.9(1), N(1) Ni(1) N(2) 87.38(8), O(1) Ni(1) C(3) 87.22(9), N(1) Ni(1) C(3) 95.9(1), N(2) Ni(1) O(1) 89.64(8), N(1) N(2) O(1) C(3)

4 Figure S3. 1 H NMR spectrum of complex 2 (400 MHz, CD 2 Cl 2, r.t.): d 0.58 (t, 2H, CH 2 ), (t, 2H, CH 2 ), 2.24 (m, 6H, CH 2 ), (m, 20H, Ar-H). Figure S4. 31 P{H} NMR spectrum of complex 2 (162 MHz, CD 2 Cl 2, r.t.): d (d, J P,P 68.0), (d, J P,P 72.0). 3

5 Figure S5. 1 H NMR spectrum of complex 3 (400 MHz, CD 2 Cl 2, r.t.): d 0.84 (t, 2H, CH 2 ), (t, 2H, CH 2 ), 2.29 (m, 4H, CH 2 ), (m, 20H, Ar-H). Figure S6. 31 P{H} NMR spectrum of complex 3 (162 MHz, CD 2 Cl 2, r.t.): d (s), (s). 4

6 Figure S7. 1 H NMR spectrum of complex 4 (400 MHz, CD 2 Cl 2, r.t.): d 0.62 (t, 2H, CH 2 ), 1.76 (m, 4H, CH 2 ), 2.03 (m, 2H, CH 2 ), 2.14 (m, 2H, CH 2 ), 2.26 (t, 2H, CH 2 ), (m, 20H, Ar-H). Figure S8. 31 P{H} NMR spectrum of complex 4 (162 MHz, CD 2 Cl 2, r.t.): d (d, J P,P 8.0), (d, J P,P 32.0). 5

7 Figure S9. 1 H NMR spectrum of complex 5 (400 MHz, CD 2 Cl 2, r.t.): d 0.83 (t, 2H, CH 2 ), 1.96 (t, 2H, CH 2 ), (m, 10H, Ar-H). Figure S10. 1 H NMR spectrum of complex 5 (400 MHz, CD 2 Cl 2, r.t.): d 0.20 (t, 2H, CH 2 ), 1.63 (t, 2H, CH 2 ), 2.40 (m, 18H, CH 3 ), 6.92 (m, 8H, Ar-Ph, Ar-Py), 7.53 (m, 1H, Ar-Py), 8.07 (m, 2H, Ar- Py). 6

8 2. NMR reactions of Ni-lactones and CH 3 I Figure S11. 1 H NMR spectrum (400 MHz, CD 2 Cl 2 ) methylation of complex 1 with 10 equiv. CH 3 I after 30 min (1 equiv. internal standard CHCl 3, d = 7.32 ppm). The vinylic protons of methyl acrylate were identified as multiplets at c.a ppm, 6.11 ppm and 5.81 ppm. From the integrals of these peaks, the yield of methyl acrylate was calculated to be 0.3 %. Figure S12. 1 H NMR spectrum (400 MHz, CD 2 Cl 2 ) methylation of complex 1 with 10 equiv. CH 3 I after 3 h (1 equiv. internal standard CHCl 3, d = 7.32 ppm). The vinylic protons of methyl acrylate were identified as multiplets at c.a ppm, 6.11 ppm and 5.81 ppm. From the integrals of these peaks, the yield of methyl acrylate was calculated to be 2 %. 7

9 Figure S13. 1 H NMR spectrum (400 MHz, CD 2 Cl 2 ) methylation of complex 1 with 100 equiv. CH 3 I after 30 min (1 equiv. internal standard CHCl 3, d = 7.32 ppm). The vinylic protons of methyl acrylate were identified as multiplets at c.a ppm, 6.07 ppm and 5.78 ppm. From the integrals of these peaks, the yield of methyl acrylate was calculated to be 2 %. Figure S14. 1 H NMR spectrum (400 MHz, CD 2 Cl 2 ) methylation of complex 1 with 100 equiv. CH 3 I, after 3 h (1 equiv. internal standard CHCl 3, d = 7.32 ppm). The vinylic protons of methyl acrylate were identified as multiplets at c.a ppm, 6.07 ppm and 5.78 ppm. From the integrals of these peaks, the yield of methyl acrylate was calculated to be 56 %. 8

10 Figure S15. 1 H NMR spectrum (400 MHz, CD 2 Cl 2 ) methylation of complex 3 with 10 equiv. CH 3 I after 24 h (1 equiv. internal standard CHCl 3, d = 7.32 ppm). The vinylic protons of methyl acrylate were identified as multiplets at c.a ppm, 6.11 ppm and 5.82 ppm. From the integrals of these peaks, the yield of methyl acrylate was calculated to be 18 %. Figure S16. 1 H NMR spectrum (400 MHz, CD 2 Cl 2 ) methylation of complex 3 with 100 equiv. CH 3 I after 24 h (1 equiv. internal standard CHCl 3, d = 7.32 ppm). The vinylic protons of methyl acrylate were identified as multiplets at c.a ppm, 6.08 ppm and 5.80 ppm. From the integrals of these peaks, the yield of methyl acrylate was calculated to be 48 %. 9

11 3. IR measurements of the reaction of Ni-lactones and CH 3 I Figure S17. IR spectra before and after 24 h of reaction (solid line: IR of nickelalactone 1 in CH 2 Cl 2, dotted line: IR of reaction mixture after 24 h). Figure S18. IR spectra before and after 24 h of reaction (solid line: IR of nickelalactone 2 in CH 2 Cl 2, dotted line: IR of the reaction mixture after 24 h). 10

12 Figure S19. IR spectra before and after 24 h of reaction (solid line: IR of nickelalactone 3 in CH 2 Cl 2, dotted line: IR of the reaction mixture after 24 h). Figure S20. IR spectra before and after 24 h of reaction (solid line: IR of nickelalactone 4 in CH 2 Cl 2, broken line: IR of the reaction mixture after 24 h). 11

13 Figure S21. IR spectra before and after 24 h of reaction (solid line: IR of nickelalactone 5 in CH 2 Cl 2, broken line: IR of the reaction mixture after 24 h). 12

14 4. DFT investigations With DFT calculations, it was attempted to quantify the mechanism for the lactone-to-acrylic ester conversion (Scheme 1). The choice of bidentate ligands is to use the best ligand of the experimental study, therefore tmeda has been chosen. Table S1 shows the energetic profile (B3LYP/6-31+G**) of the considered pathway. The reported energies are reaction enthalpies ( H) and free energies ( G) in kcal/mol, scaled to the starting material A. Table S1. Energetic overview. A TSA B TS_BC C TS_CD D H [kcal/mol] G [kcal/mol] From the results it can be concluded that the rate-determining step is the addition of the methyl iodide to open the lactone. tmeda and bipy show equal barriers of 58.6 kcal/mol (free energy). Figure 1 shows the optimized geometry for all three transition states for occurring in this mechanism. The geometry of TS_AB shows that the methyl iodide is already separated and the carbon atom of the methyl group shows significantly sp2 hybridization character (partly cationic). Although no solvent effects have yet been included, DCM is less polar and therefore also this higher barrier is expected even with respect of such effects. Figure S22. Structures of all calculated transition states with selected bond lengths. 13

15 Intermediate B can be regarded as the Ni bound propionic acid methyl ester. The formation is endergonic compared to the starting compounds. This result might lead to an explanation why this reaction can only proceed with a hundred-fold excess of methyl iodide. The second step is the β H-shift from the propionic acid derivative to create the? 2 -coordinated olefin in order to transform the alkylic acid ester into an acrylic acid ester. The corresponding transition state TS_BC shows a barrier of 24.5 kcal/mol respectively on the G scale. In case of tmeda, the bidentate ligand loses almost one of his nitrogen-nickel contacts according to the elongation from 2.12 to 2.43 Å. TS_BC is a late transition state with the hydrogen already transferred to the nickel and the? 2 -coordination of the olefin already established. The resulting intermediate C is even more endothermic and endergonic than A and B. The reaction sequence is finally completed by the dissociation of the acryl acid methyl ester leaving back the corresponding bidentate Ni-hydrido-iodo complex in 4. The barrier height in this TS_CD is 13.8 kcal/mol for tmeda. This is also a late transition state while the C-Ni distances have already been elongated to around 3.4 Å. 14

16 5. X-ray single crystal structure data for compound 1 X-ray single crystal structure: The X-ray diffraction measurement was performed on a single crystal of 1 coated with Paratone oil and mounted on a Kaptan loop. The crystal was frozen under a stream of dinitrogen while data were collected on an X-ray diffractometer equipped with a CCD detector (APEX II,?-CCD), a rotating anode (Bruker AXS, FR591) with MoK a radiation (? = Å), and a graphite monochromator by using the SMART software package. [S1] A matrix scan using at least 20 centered reflections was used to determine the initial lattice parameters. Reflections were merged and corrected for Lorenz and polarization effects, scan speed, and background using SAINT [S2] Absorption corrections, including odd and even ordered spherical harmonics were performed using SADABS. [S3] Space group assignment was based upon systematic absences, E statistics, and successful refinement of the structures. The structure was solved by direct methods with the aid of successive difference Fourier maps, and was refined against all data using WinGX. [S4] based on Sir-92. [S5] All non-hydrogen atoms were refined with anisotropic displacement parameters, whereas all hydrogen atoms were refined with isotropic displacement parameters. Full-matrix least-squares refinements were carried out by minimizing Sw(F o 2 -F c 2 ) 2 with SHELXL-97 [S6] weighting scheme. Neutral atom scattering factors for all atoms and anomalous dispersion corrections for the non-hydrogen atoms were taken from International Tables for Crystallography. [S7] Images of the crystal structures were generated by Diamond 3.1. [S8] [S1] SMART Software Users Guide, Version 5.1 (Bruker Analytical X-Ray Systems, Inc, Madison, WI, 1999). [S2] SAINT Software Users Guide, Version 7.0 (Bruker Analytical X-Ray Systems, Inc, Madison, WI, 1999). [S3] G. M. Sheldrick, SADABS, Version 2.03 (Bruker Analytical X-Ray Systems, Inc, Madison, WI, 2000). [S4] L. J. Farrugia, WinGX (Version January 2005), J. Appl. Cryst. 1999, 32, [S5] A. Altomare, G. Cascarano, C. Giacovazzo, A. Guagliardi, M. C. Burla, G. Polidori, M. Camalli SIR92, J. Appl. Crystallogr. 1994, 27, [S6] G. M. Sheldrick, SHELXL-97, Program for Crystal Structure Refinement, Göttingen [S7] International Tables for Crystallography, Vol. C, Tables (pp ), (pp ), and (pp ), Wilson, A. J. C., Ed., Kluwer Academic Publishers, Dordrecht, The Netherlands, [S8] K. Brandenburg, DIAMOND Version 3.1, Crystal and Molecular Structure Visualization, 2005, Bonn. 15

17 Compound Name formula (tmeda)ni-lactone C 9 H 20 N 2 O 2 Ni M r (g/mol) Crystal description green fragment Crystal dimensions (mm 3 ) 0.05 x 0.13 x 0.15 Temperature (K) 173(2) crystal system, space group monoclinic, P2 1 /c a(å) (9) b(å) (8) c(å) (16) a( ) 90 b( ) (5) g( ) 90 V(Å 3 ) (2) Z 4 d calc (g/cm 3 ) 1.45 F µ (mm -1 ) Index ranges (±h, ±k, ±l) 11/-11, 9/-8, 19/-19? ranges ( ) Collected reflections Unique reflections [all data] 2236 R int / R s / Unique reflections [t 0 >2 s(t 0 )] 1950 Data/Restraints/Parameter 2236/0/207 GoF (on F 2 ) R 1 /wr 2 [t 0 >2 s(t 0 )] / R 1 /wr 2 [all data] / Max./Min. residual electron density 0.624/