Supporting Information

-S1- of 18 Functional Group Chemistry at the Group 4 Bent Metallocene Frameworks: Formation and Metal-free Catalytic Hydrogenation of Bis(imino-Cp)zirconium Complexes Kirill V. Axenov, Gerald Kehr, Roland Fröhlich, Gerhard Erker Organisch-Chemisches Institut der Universität Münster, Corrensstrasse 40, 48149 Münster, Germany erker@uni-muenster.de Supporting Information Table of Contents General Information Materials Experimental Procedures S2 S2 S3

-S2- of 18 General Information. All reactions were carried out under argon atmosphere with Schlenk-type glassware or in a glovebox. Solvents (including deuterated solvents used for NMR spectroscopy) were dried and distilled under argon prior to use. The following instruments were used for physical characterization of the compounds. Elemental analyses: Foss-Heraeus CHNO-Rapid. NMR: Bruker AC 200 P ( 1 H, 200 MHz; B, 64 MHz), ARX 300 ( 1 H, 300 MHz; 19 F, 282 MHz), Varian 500 MHz INOVA ( 1 H, 500 MHz; B, 160 MHz; 19 F, 470 MHz), Varian UNITY plus NMR spectrometer ( 1 H, 600 MHz; 13 C, 151 MHz; 19 F, 564 MHz). Assignments of the resonances are supported by 2D experiments and chemical shift calculations. B NMR spectra were referenced to an external Et 2 O BF 3 (neat) sample (δ B = 0); 19 F NMR spectra were referenced to an external CFCl 3 (neat) sample (δ 19 F = 0). X-ray diffraction: Data sets were collected with Nonius KappaCCD diffractometers, in case of Mo-radiation equipped with a rotating anode generator. Programs used: data collection COLLECT (Nonius B.V., 1998), data reduction Denzo-SMN (Z. Otwinowski, W. Minor, Methods in Enzymology, 1997, 276, 307-326), absorption correction SORTAV (R.H. Blessing, Acta Cryst. 1995, A51, 33-37; R.H. Blessing, J. Appl. Cryst. 1997, 30, 421-426) and Denzo (Z. Otwinowski, D. Borek, W. Majewski, W. Minor, Acta Cryst. 2003, A59, 228-234), structure solution SHELXS-97 (G.M. Sheldrick, Acta Cryst. 1990, A46, 467-473), structure refinement SHELXL-97 (G.M. Sheldrick, Acta Cryst. 2008, A64, 2-122), graphics XP (BrukerAXS, 2000). Materials. 6-dimethylaminofulvene (1) [Hafner, K.; Schultz, G.; Wagner, K. Liebigs Ann. Chem. 1964, 678, 39. Hafner, K.; Vöpel, K. H.; Ploss, G.; König, C. Org. Synth. 1967, 47, 52], Zr(NMe 2 ) 2 Cl 2 (THF) 2 (5) [Brenner, S.; Kempe, R.; Arndt, P. Z. Anorg. Allgem. Chem. 1995, 621, 2121], and B(C 6 F 5 ) 3 [Massey, A. G.; Park, A. J.; Stone, F. G. A. Proc. Chem. Soc. 1963, 212. Massey, A. G.; Park, A. J. J. Organomet. Chem. 1964, 2, 245] were prepared according to modified literature procedures. The THF-free lithium [(N-2,6- diisopropylphenyl)formimidoyl]cyclopentadienide (3) was synthesized based on the procedure published by us previously [Kunz, K.; Erker, G.; Fröhlich, R. Organometallics 2001, 20, 392] using Et 2 O as a solvent instead of THF.

-S3- of 18 X-ray crystal structure analysis of lithium [(N-2,6-diisopropylphenyl)formimidoyl]cyclopentadienide THF solvate 3: The salt 3 was prepared as it was descriebed by us previously [Kunz, K.; Erker, G.; Fröhlich, R. Organometallics 2001, 20, 392]. The single crystals of 3 suitable for X-ray single crystall diffraction studies were obtained via layering by a pentane of a THF solution at -30 C. X-ray crystal structure analysis of 3. formula C 18 H 22 LiN * 3 C 4 H 8 O, M = 475.62, red crystal 0.60 x 0.40 x 0.15 mm, a = 17.307(1), b = 9.958(1), c = 17.545(1) Å, β = 101.39(1), V = 2964.2(4) Å 3, ρ calc = 1.066 g cm -3, μ= 0.515 mm -1, empirical absorption correction (0.747 T 0.927), Z = 4 monoclinic, space group P2 1 /c (No. 14), λ= 1.54178 Å, T = 223(2) K, ω and φ scans, 21098 reflections collected (±h, ±k, ±l), [(sinθ)/λ] = 0.60 Å -1, 5218 independent (R int = 0.034) and 4601 observed reflections [I 2 σ(i)], 320 refined parameters, R = 0.069, wr 2 = 0.201, max. residual electron density 0.28 (-0.21) e Å -3, hydrogen atoms calculated and refined as riding atoms.

-S4- of 18 Preparation of the ligand 5. Major isomer (anti-5): 1 H NMR (600 MHz, CD 2 Cl 2, 253 K): δ 7.36 (t, 3 J HH = 7.8 Hz, 1H, p-ar), 7.26 (d, 3 J HH = 7.8 Hz, 2H, m-ar), 6.99 (d, 3 J HH = 14.2 Hz, 1H, =CHN), 6.91 (br. d, 3 J HH = 14.2 Hz, 1H, NH), 6.71 (dm, J HH = 4.7 Hz, 1H, Cp α ), 6.51 (m, 1H, Cp β ), 6.41 (ddd, J HH = 4.7 Hz, 2.1 Hz, 1.7 Hz, 1H, Cp α ), 6.27 (ddd, J HH = 4.6 Hz, 2.4 Hz, 1.4 Hz, 1H, Cp β ), 3.29 (sept, 3 J HH = 6.8 Hz, 2H, CH(iPr)), 1.23 (d, 3 J HH = 6.8 Hz, 12H, CH 3 (ipr)). 13 C{ 1 H} NMR (151 MHz, CD 2 Cl 2, 253 K): δ 146.5 (=CHN), 145.7 (o-ar), 135.0 (i-ar), 128.4 (p-ar), 126.5 (Cp β ), 124.0 (m-ar), 123.5 (Cp α ), 121.9 (Cp β ), 8.3 (i-cp), 1.6 (4-Cp α ), 28.3 (CH(iPr)), 23.6 (CH 3 (ipr)). Minor isomer (syn-5): 1 H NMR (600 MHz, CD 2 Cl 2, 253 K): δ 7.45 (t, 3 J HH = 7.8 Hz, 1H, p-ar), 7.32 (d, 3 J HH = 7.3 Hz, 1H, =CHN), 7.30 (d, 3 J HH = 7.8 Hz, 1H, m-ar), 6.49 (d, 3 J HH = 7.3 Hz, 1H, NH), 6.35 (dm, J HH = 4.7 Hz, 1H, Cp α ), 6.12 (ddd, J HH = 4.6 Hz, 2.3 Hz, 1.4 Hz, 1H, Cp β ), 6.05 (m, 1H, Cp β ), 4.97 (dm, J HH = 4.7 Hz, 1H, Cp α ), 3.13 (sept, 3 J HH = 6.8 Hz, 2H, CH(iPr)), 1.18, 1.10 (each d, each 3 J HH = 6.8 Hz, each 6H, CH 3 (ipr)). 13 C{ 1 H} NMR (151 MHz, CD 2 Cl 2, 253 K): δ 146.4 (o-ar), 143.6 (=CHN), 134.2 (i-ar), 129.1 (p-ar), 125.4 (Cp β ), 124.3 (m-ar), 124.8 (Cp α ), 120.5 (Cp β ), 8.1 (i-cp), 5.1 (1-Cp α ), 28.4 (CH(iPr)), 24.4 (CH 3 (ipr)), 23.0 (CH 3 (ipr)). 2,6-Di-i-propylaniline: 1 H NMR (600 MHz, CD 2 Cl 2, 253 K): δ 7.04 (d, 3 J HH = 7.8 Hz, 2H, m-ar), 6.78 (t, 3 J HH = 7.8 Hz, 1H, p-ar), 3.82 (br. s, 2H, NH 2 ), 2.92 (sept, 3 J HH = 6.8 Hz, 2H, CH(iPr)), 1.26 (d, 3 J HH = 6.8 Hz, 12H, CH 3 (ipr)). 13 C{ 1 H} NMR (151 MHz, CD 2 Cl 2, 253 K): δ 140.5 (i-ar), 132.2 (o-ar), 122.6 (m-ar), 8.2 (p-ar), 27.8 (CH(iPr)), 22.3 (CH 3 (ipr)).

-S5- of 18 Preparation of bis(amido) complexes 6 and 7, L 2 Zr(NMe 2 ) 2 and L 2 Zr(NMe 2 )(NH-2,6-iPr 2 C 6 H 3 ). Compound 7: The solution of Zr(NMe 2 ) 4 (2.63 g, 9.84 mmol) in dry benzene (20 ml) was added to the solution of ligand 5 (6.64 g, 19.68 mmol) in dry benzene (30 ml) at room temperature. The reaction mixture was stirred overnight. After removal all volatiles under vacuum the brown residue was washed with pentane (50 ml). After decantation of the pentane phase the residue was washed with pentane (20 ml) and dried under vacuum, which gave 2.8 g (35 %) of product 7 as yellow-brown powder. Crystals of 7 suitable for X-ray single crystal diffraction analysis were grown from Et 2 O solution at -30 C. (C 50 H 68 ZrN 4 calcd. C, 73.57; H, 8.40; N, 6.86, found: C, 74.26; H, 8.70; N, 6.31). In d 6 -benzene: 1 H NMR (600 MHz, C 6 D 6, 298 K): δ 7.88 (s, 2H, N=CH), 7.12 (m, 4H, m-ar), 7.09 (m, 2H, p-ar), 7.06 (m, 2H, m-ar Zr ), 6.96 (m, 1H, p-ar Zr ), 6.94 (α ), 6.46 (α), 6.10 (β ), 5.96 (β) (each br m, each 2H, C 5 H 4 ), 3.47 (br, 2H, CH(iPr) Zr ), 3.18 (sept, 4H, 3 J HH = 6.8 Hz, CH(iPr)), 2.85 (s, 6H, CH 3 N), 1.21 (br, 12H, CH 3 (ipr) Zr ), 1.20 (d, 12H, 3 J HH = 6.8 Hz, CH 3 (ipr)), 1.13 (d, 12H, 3 J HH = 6.8 Hz, CH 3 (ipr)); 13 C{ 1 H} NMR (151 MHz, C 6 D 6, 298 K): δ 156.7 (CH=N), 153.1 (i-ar Zr ), 149.5 (i-ar), 138.1 (o-ar), 124.8 (p-ar), 123.5 (m-ar), 123.1 (br, m-ar Zr ), 122.2 (p-ar Zr ), 9.9 (i-c 5 H 4 ), 7.7 (α-c 5 H 4 ), 3.1 (br, β -C 5 H 4 ), 2.7 (α -C 5 H 4 ), 109.9 (br, β-c 5 H 4 ), 50.9 (CH 3 N), 28.3 (CH(iPr)), 28.2 (br, CH(iPr) Zr ), 24.5 (br, CH 3 (ipr) Zr ), 23.9 (CH 3 (ipr)), 23.8 (CH 3 (ipr)). In d 8 -toluene: 1 H NMR (600 MHz, d 8 -toluene, 298 K): δ 7.79 (s, 2H, N=CH), 7.02 (m, 4H, m-ar), 6.98 (m, 2H, p-ar), 6.96 (m, 2H, m-ar Zr ), 6.84 (α ), 6.83 (m, 1H, p-ar Zr ), 6.38 (α), 6.02 (β ), 5.89 (β) (each br m, each 2H, C 5 H 4 ), 3.41 (br, 2H, CH(iPr) Zr ), 3.08 (sept, 4H, 3 J HH = 6.8 Hz, CH(iPr)), 2.79 (s, 6H, CH 3 N), 1.13 (d, 12H, 3 J HH = 6.8 Hz, CH 3 (ipr)), 1.12 (br, 12H, CH 3 (ipr) Zr ), 1.05 (d, 12H, 3 J HH = 6.8 Hz, CH 3 (ipr)); 1 H NMR (600 MHz, d 8 -toluene, 353 K): δ 7.90 (s, 2H, N=CH), 7.01 (m, 4H, m-ar), 6.96 (m, 2H, p-ar), 6.95 (br m, 2H, m-ar Zr ), 6.83 (α ), 6.81 (m, 1H, p-ar Zr ), 6.44 (α), 6.06 (β ), 5.90 (β) (each br.s, each 2H, C 5 H 4 ), 3.42 (br sept, 2H, 3 J HH = 6.7 Hz, CH(iPr) Zr ), 3.08 (sept, 4H, 3 J HH = 6.8 Hz, CH(iPr)), 2.83 (s, 6H, CH 3 N), 1.12 (d, 12H, 3 J HH = 6.8 Hz, CH 3 (ipr)), 1.12 (d, 12H, 3 J HH = 6.7 Hz, CH 3 (ipr) Zr ), 1.05 (d, 12H, 3 J HH = 6.8 Hz, CH 3 (ipr));

-S6- of 18 13 C{ 1 H} NMR (151 MHz, C 6 D 6, 353 K): δ 156.8 (CH=N), 153.3 (i-ar Zr ), 149.8 (i-ar), 140.5 (o-ar Zr ), 138.5 (o- Ar), 124.9 (p-ar), 123.6 (m-ar), 123.2 (m-ar Zr ), 122.5 (p-ar Zr ), 120.9 (i-c 5 H 4 ), 7.4 (α-c 5 H 4 ), 3.7 (br., β - C 5 H 4 ), 3.3 (α -C 5 H 4 ), 109.8 (β-c 5 H 4 ), 51.1 (CH 3 N), 28.5 (CH(iPr)), 28.1 (CH(iPr) Zr ), 24.5 (CH 3 (ipr) Zr ), 23.9 (CH 3 (ipr)), 23.9 (CH 3 (ipr)). Compound 6: The decanted from the precipitation of complex 7 pentane solution was filtered through celite and evaporated under vacuum, which gave 4.40 g (65%) of the target complex 6 as yellow-brown solid. Crystals of 6 suitable for X-ray single crystal diffraction analysis were grown from pentane solution at -30 C. (C 40 H 56 ZrN 4 calcd. C, 70.23; H, 8.25, found: C, 70.78; H, 8.64). 1 H NMR (500 MHz, C 6 D 6, 298 K): δ 7.96 (s, 2H, N=CH), 7.18 (m, 4H, m-ar), 7.13 (m, 2H, p-ar), 6.71 (α), 6.01 (β) (each m, each 4H, C 5 H 4 ), 3.28 (sept, 4H, 3 J HH = 6.9 Hz, CH(iPr)), 2.83 (s, 12H, CH 3 N), 1.22 (d, 24H, 3 J HH = 6.9 Hz, CH 3 (ipr)); 13 C{ 1 H} NMR (126 MHz, C 6 D 6, 298 K): δ 156.5 (CH=N), 150.0 (i-ar), 138.2 (o-ar), 124.6 (p-ar), 123.5 (m-ar), 121.3 (i-c 5 H 4 ), 4.4 (α-c 5 H 4 ), 1.3 (β-c 5 H 4 ), 49.1 (CH 3 N), 28.1 (CH(iPr)), 24.1 (CH 3 (ipr)).

-S7- of 18 Preparation of the dichlorozirconocene complex 9. In a glovebox (Me 2 N) 2 ZrCl 2 (THF) 2 (0.78 g, 1.98 mmol) and ligand 5 (1.20 g, ~4.74 mmol) were dissolved in toluene (20 ml). The reaction mixture was first stirred for 3 h at 120 C and additionally overnight at room temperature. After filtration all volatiles were removed under vacuum, and the resulted brown residue was washed with pentane (12 ml). After removal of the pentane phase by syringe, the oily brown precipitation was dried in vacuo, which gave (0.520 g; 39%) of the product 9 as a red-brown solid. The second crop of the product precipitated at room temperature as crystalline solid from the pentane washings. After removing the pentane solvent by decantation, the crystalline residue was dried in vacuo, which gave additional amount of the target complex (0.358 g). The combined yield of complex 9 was 0.878 g, 67%. (C 36 H 44 N 2 Cl 2 Zr) calcd. C, 64.84; H, 6.65; N, 4.20, found: C, 64.72; H, 6.85; N, 4.24. 1 H NMR (600 MHz, C 6 D 6, 298 K): δ 7.99 (s, 2H, =CHN), 7.15 (m, 6H, Ar), 6.72(α), 5.89(β) (each m, each 4H, Cp), 3.25 (sept, 3 J HH = 6.9 Hz, 4H, CH(iPr)), 1.24 (d, 3 J HH = 6.9 Hz, 24H, CH 3 (ipr)). 13 C{ 1 H} NMR (151 MHz, C 6 D 6, 298 K): δ 156.2 (=CHN), 149.2 (i-ar), 137.9 (o-ar), 125.1 (p-ar), 124.6 (i-cp), 123.5 (m-ar), 9.4(α), 4.5(β) (Cp), 28.2 (CH(iPr)), 24.0 (CH 3 (ipr)). Treatment of dichlorozirconocene complex 9 with B(C 6 F 5 ) 3. In a glovebox complex 9 (22.5 mg, 34 μmol) was placed into a NMR tube and dissolved in toluene-d 8 (0.2 ml). The NMR tube was placed into the special

-S8- of 18 adapter equipped with septum and taken out from glovebox. The system was cooled to 78 C with aceton/dry ice bath, and the precooled solution of B(C 6 F 5 ) 3 (36 mg, 68 μmol) in toluene-d 8 (0.6 ml) was added to the NMR tube. The NMR tube was sealed, shaken for few seconds and kept at -78 C. The resulting mixture was investigated NMR spectroscopically at - 40 C. 1 H NMR (600 MHz, toluene-d 8, 233 K): δ 7.87 (s, 2H, =CHN), 7.12 (m, 6H, Ar), 6.65(α), 5.76(β) (each m, each 4H, Cp), 3.23 (sept, 3 J HH = 6.9 Hz, 4H, CH(iPr)), 1.25 (d, 3 J HH = 6.9 Hz, 24H, CH 3 (ipr)); 19 F NMR (470 MHz, toluene-d 8, 233 K): δ -123.5 (s, o-c 6 F 5 ), -135.3 (s, p-c 6 F 5 ), - 154.6 (s, m-c 6 F 5 ). For comparison: 19 F NMR of B(C 6 F 5 ) 3 (470 MHz, toluene-d 8, 233 K): δ -123.6 (s, o-c 6 F 5 ), - 135.3 (s, p-c 6 F 5 ), -154.6 (s, m-c 6 F 5 ). We see the formation of some products and broadening of the signals both of B(C 6 F 5 ) ( 19 F NMR) and the compound 9 ( 1 H NMR). Beyond this the experiment was inconclusive with regard to potential adduct formation. -123.6-135.3-154.6-8 -122-126 -130-134 -138 f1 (ppm) -142-146 -150-154 -158 19 F NMR of B(C 6 F 5 ) 3 (564 MHz, toluene-d 8, 233 K)

-S9- of 18 1 H NMR of 9/B(C 6 F 5 ) 3 (600 MHz, toluene-d 8, 233 K) 19 F NMR of 9/B(C 6 F 5 ) 3 (564 MHz, toluene-d 8, 233 K)

-S10- of 18 Reduction of the dichlorozirconocene complex 9; Generation of complex 10. In a reference experiment benzene-d 6 (1 ml) was added in the glovebox in a Schlenk flask to a mixture of complex 9 (0.2 g, 0.30 mmol) and B(C 6 F 5 ) 3 (77 mg, 0.15 mmol). The flask was connected to the hydrogen bottle. The system was flushed with hydrogen and then properly closed with the tap. The hydrogen pressure in the reaction flask was raised up to 2 bars and the reaction mixture was stirred in a glovebox overnight at room temperature. After evaporation of all volatiles in vacuo a mixture of 10 and, was obtained as a light-yellow solid (0.277 g, 100%). Calculated for 10 : (1 : 1): (C 90 H 98 BCl 4 F 15 N 4 Zr 2 ) calcd. C, 58.25; H, 5.32; N, 3.02, calculated for 10 : (2 : 1): (C 126 H 144 BCl 6 F 15 N 6 Zr 3 ) calcd. C, 59.94; H, 5.75; N, 3.33, found: C, 57.97; H, 4.91; N, 3.33) 1 H NMR (600 MHz, C 6 D 6, 298 K): δ 7.07 (m, 6H, Ar), 6.13(α), 5.68(β) (each m, each 4H, Cp), 4.17 (s, 4H, CH 2 ), 3.87 (BH), 3.32 (sept, 3 J HH = 6.5 Hz, 4H, CH(iPr)), 1.21 (d, 3 J HH = 6.5 Hz, 24H, CH 3 (ipr)), n.o. (NH). 13 C{ 1 H} NMR (151 MHz, C 6 D 6, 298 K): δ 148.8 (dm, 1 J CF 235 Hz, C 6 F 5 ), 143.0 (o-ar), 140.7 (br., i-ar), 138.8 (dm, 1 J CF 243 Hz, p-c 6 F 5 ), 137.3 (dm, 1 J CF 248 Hz, C 6 F 5 ), n.o. (i-c 6 F 5 ), 131.8 (i-cp), 126.0 (p-ar), 124.3 (m-ar), 7.6 (br., α), 1.8 (β) (Cp), 51.0 (CH 2 ), 28.1 (CH(iPr)), 24.4 (CH 3 (ipr)). 19 F NMR (470 MHz, C 6 D 6, 298 K): δ -133.4 (m, o-c 6 F 5 ), -161.7 (t, 3 J FF = 20.4 Hz, p-c 6 F 5 ), -165.2 (m, m-c 6 F 5 ); B{ 1 H} NMR (160 MHz, C 6 D 6, 298 K): δ -24.4 (ν 1/2 100 Hz); B NMR (160 MHz, C 6 D 6, 298 K): δ -24.4 (br. d, 1 J BH 76 Hz). Crystals of complex 10 suitable for the X-ray single crystal diffraction analysis were grown from a pentane solution at -33 C.

-S- of 18 The following additional experiments were carried out to identify the individual products 10 and form the reaction mixture. The experiment was carried out in a glovebox using a Schlenk flask: D 6 -benzene- (0.6 ml) was added to a mixture of complex 9 (50 mg, 0.075 mmol) and B(C 6 F 5 ) 3 (0.5 equivalents, 19 mg, 0.0375 mmol). The flask was connected to the hydrogen bottle. The system was flushed with hydrogen and then properly closed with the tap. The hydrogen pressure in the reaction flask was raised up to 2 bars and the reaction mixture was stirred in a glovebox overnight at room temperature. After evaporation of all volatiles in vacuo a mixture of 10 and was obtained as a light-yellow solid (~100%). The sample was re-dissolved in d 8 - THF and the NMR experiments were measured at low temperature under static conditions ("frozen" proton transfer). 10 : 2 : 1. 10 * 10/ 10 10/ * 1 H NMR (600 MHz, d 8 -THF, 298 K) 10/ 10 10.5 9.5 9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 1 H NMR (600 MHz, d 8 -THF, 198 K)

-S12- of 18 Generation of complex. The experiment was carried out in a glovebox using a Schlenk flask: D 6 -benzene (1 ml) was added to a mixture of complex 9 (0.1 g, 0.15 mmol) and B(C 6 F 5 ) 3 (1.2 equivalents, 92 mg, 0.18 mmol). The flask was connected to the hydrogen bottle. The system was flushed with hydrogen and then properly closed with the tap. The hydrogen pressure in the reaction flask was raised up to 2 bars and the reaction mixture was stirred in a glovebox overnight at room temperature. After evaporation of all volatiles in vacuo a mixture of 10, and 12, was obtained as a light-yellow solid (~100%). The sample was re-dissolved in d 8 -THF and the NMR experiments were measured at low temperature under static conditions ("frozen" proton transfer). 10 : : 12 5 : 20 : 3. * /12/10 * /12 /10 /12 /10 10.5 9.5 9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 1 H NMR (600 MHz, d 8 -THF, 298 K) /12 12 /12 BH 10 12 10 10 10.5 9.5 9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 1 H NMR (600 MHz, d 8 -THF, 198 K)

-S13- of 18 Preparation of complex 12. D 6 -benzene (1 ml) was added in a glovebox to a mixture of complex 9 (0.2 g, 0.168 mmol) and B(C 6 F 5 ) 3 (172 mg, 0.336 mmol, 2 equivalents). The glass tube containing the reaction mixture was closed with a dual valve Teflon adapter, placed into a steel autoclave inside a glovebox, then the autoclave was properly closed and removed from glovebox. The autoclave was charged with dihydrogen to a pressure of 60 bar, and the reaction mixture was stirred for 3 h at ambient temperature. After venting hydrogen to ambient pressure inside the autoclave the glass tube was placed in the glovebox. The product is only sparingly soluble in benzene and precipitated as a brown oil. Benzene was removed from the precipitated product by decantation. The oily product was dissolved in 1 ml of dry dichloromethane. After evaporation of all volatiles under vacuum the product 12 was obtained as a light-brown solid (160 mg, 81%). The elemental analysis was obtained from the material prepared analogously from complex 9 (0.2 g, 0.168 mmol) and B(C 6 F 5 ) 3 (172 mg, 0.336 mmol, 2 equivalents). The procedure was as followed: D6-benzene (1 ml) was added in the glovebox in a Schlenk flask to a mixture of complex 9 (0.2 g, 0.168 mmol) and B(C 6 F 5 ) 3 (172 mg, 0.336 mmol, 2 equivalents). The flask was connected to the hydrogen bottle. The system was flushed with hydrogen and then properly closed with the tap. The hydrogen pressure in the reaction flask was raised up to 2 bars and the reaction mixture was stirred in a glovebox overnight at room temperature. The solvent was decanted from the oil precipitation of the product 12. The oil product was transferred into another Schlenk flask with help of benzene-d 6 (1 ml), and the benzene phase was decanted from oil precipitation. This oil residue was dried in vacuo, which led to a product 12, obtained as a light-yellow solid. (C 72 H 52 B 2 Cl 2 F 30 N 2 Zr) calcd. C, 50.90; H, 3.09; N, 1.65, found: C, 51.; H, 3.04; N, 2.05). Other further experiments gave slightly deviated elemental analysis results (up to 2.5 % C deviation).

-S14- of 18 The NMR identification of 12 was achieved from the spectra in d 8 -THF under "static" conditions at low temperature: The experiment was carried out in a glovebox using a Schlenk flask: D 6 -benzene (1 ml) was added to a mixture of complex 9 (0.1 g, 0.15 mmol) and B(C 6 F 5 ) 3 (2.3 equivalents, 177 mg, 0.345 mmol). The flask was connected to the hydrogen bottle. The system was flushed with hydrogen and then properly closed with the tap. The hydrogen pressure in the reaction flask was raised up to 2 bars and the reaction mixture was stirred in a glovebox overnight at room temperature. The solvent was decanted from the oil precipitation of the product mixture of and 12. The oil products were transferred into another Schlenk flask with help of benzene-d 6 (1 ml), and the benzene phase was decanted from oil precipitation. This oil residue was dried in vacuo, which led to a mixture of and 12, obtained as a light-yellow solid (0.100 g). The sample was re-dissolved in d 8 -THF and the NMR experiments were measured at low temperature under static conditions ("frozen" proton transfer). : 12 1 : 5: * 12/ * 12/ 12 12 10.5 9.5 9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 1 H NMR (600 MHz, d 8 -THF, 298 K) 0.5 12/ 12/ 12 BH 10.5 9.5 9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 1 H NMR (600 MHz, d 8 -THF, 198 K)

-S15- of 18 Control experiment: Attempted catalytic hydrogenation of the silyl enol ether 15 and the complex 9 in the absence of B(C 6 F 5 ) 3. In a glovebox the silyl enol ether 15 (163 mg, 0.95 mmol, 20 equivalents) was added to a Schlenk flask containing a solution of complex 9 (32 mg, 0.047 mmol) in C 6 D 6 (1.0 ml). The system was flushed with hydrogen, then properly closed with the tap. The pressure of hydrogen in the reaction flask was kept at 2 bars, and the reaction mixture was stirred at room temperature in the glovebox overnight. The resulted mixture was investigated NMR spectroscopically. It contained only the starting materials. 1 H NMR (200 MHz, C 6 D 6, 298 K): compound 15: δ 4.19, 4.04 (each m, each 1H, =CH 2 ), 1. (d, 9H, J HH = 0.9 Hz, t-bu), 0.17 (d, 9H, J HH = 0.9 Hz, SiMe 3 ); complex 9: δ 7.98 (s, 2H, =CHN), 7.15 (m, 6H, Ar), 6.72(α), 5.91(β) (each m, each 4H, Cp), 3.22 (sept, 3 J HH = 6.9 Hz, 4H, CH(iPr)), 1.23 (d, 3 J HH = 6.9 Hz, 24H, CH 3 (ipr)).

-S16- of 18 Preparation of N-(2,2-dimethylpropyl)-2,6-dimethylbenzenamine (14a); Catalytic hydrogenation of N-(2,2-dimethylpropylidene)-2,6-dimethylbenzenamine (13a). 13a 14a 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0 1 H NMR (600 MHz, 298 K): 13a (up, C 6 D 6 ), 14a (bottom, CDCl 3 /C 6 D 6 )

-S17- of 18 Preparation of N-(2,2-dimethylpropyl)-2,6-bis(1-methylethyl)benzenamine (14b); Catalytic hydrogenation of N-(2,2-dimethylpropylidene)-2,6-bis(1-methylethyl)benzenamine (13b). 13b 14b 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0 1 H NMR (298 K): 13b (up, 600 MHz, C 6 D 6 ), 14b (bottom, 500 MHz, CDCl 3 )

-S18- of 18 Preparation of trimethyl(1,2,2-trimethylpropoxy)silane (16); Catalytic hydrogenation of 1-t-butyl-1-trimethylsiloxyethene (15). 15 16 4.4 4.0 3.6 3.2 2.8 2.4 2.0 1.6 1.2 0.8 0.4 0.0 1 H NMR (298 K, 500 MHz, C 6 D 6 ): 15 (up), 16 (bottom)