Supporting Information for: The oxide-route for the preparation of mercury(ii) N-heterocyclic carbene complexes. Simon Pelz and Fabian Mohr* Fachbereich C-Anorganische Chemie, Bergische Universität Wuppertal, 42119 Wuppertal, Germany Experimental details General 1 H and 13 C NMR spectra were recorded on either a Bruker Avance 400 (400 MHz) or Bruker Avance III 600 (600 MHz) NMR spectrometer. Chemical shifts (δ) are given in ppm relative to TMS being referenced to residual solvent signals. Coupling constants (J) are given in hertz. Electrospray mass spectra were measured on a Bruker Daltonics MICROTOF instrument. Elemental analyses were carried out by staff of the microanalytical laboratory at the University of Wuppertal. All reactions were carried out under dried dinitrogen using standard Schlenk techniques. The imidazolium salts 1a-1c were prepared as described in the literature. 1,2 All other chemicals and solvents (anhydrous grade) were commercial products and used as received. Caution: Organomercury compounds are highly toxic. Neoprene gloves should be worn and an efficient hood must be used when handling these compounds. Residues should be disposed off according to local regulations for disposal of mercury waste. S1
Synthesis of halomercury NHC compounds (Route A) To a solution of imidazolium salt (0.5 g) in CH 2 Cl 2 (10 ml) was added HgO (0.5 equivalents). The resulting red suspension was stirred at room temperature until a clear solution was obtained (2-12 h). The solution was passed through celite and the filtrate was subsequently taken to dryness in vacuum. The residue was crystallized from CH 2 Cl 2 and MeOH or Et 2 O. Synthesis of halomercury NHC compounds (Route B) To a CH 2 Cl 2 solution (10 ml) containing imidazolium salt (0.2 g) and [Me 4 N]Cl (1 equivalent) was added HgO (1 equivalent). The resulting red suspension was stirred at room temperature until a clear solution was obtained (2-12 h). The solution was passed through celite and the filtrate was subsequently taken to dryness in vacuum. The residue was washed with water (2 10 ml) and Et 2 O (2 10 ml). The analytical samples were obtained by crystallization from CH 2 Cl 2 and MeOH or Et 2 O. Synthesis of halomercury NHC compounds (Route C) To a solution of imidazolium salt (0.5 g) in THF (10 ml) was added KO t Bu (1 equivalent). The solution was left to stir for ca. 30 min before the mercury halide (1 equivalent) was added. The mixture was left to stir at room temperature over night. The precipitated products were isolated by filtration and were subsequently washed with H 2 O (2 10 ml) and MeOH (2 10 ml). The products obtained from the three different reactions were identical based on NMR spectroscopic and mass spectrometric data. (2a) Colourless solid. Yields: 30% route A, 40 % route B, 45 % route C. 1 H NMR (400 MHz, dmso-d 6 ) δ = 1.15 (d, J = 6.8 Hz, 12 H, CH 3 ), 1.28 (d, J = 6.8 Hz, 12 H, CH 3 ), 2.44 (sept, J = 6.8 Hz, 4 H, CH(CH 3 ) 2 ), 7.39 (d, J = 7.8 Hz, 4 H, m-c 6 H 3 ), 7.57 (t, J = 7.8 Hz, 2 H, p-c 6 H 3 ), 8.31 (s, J H-Hg = 31 Hz, 2 H, imidazole ring). 13 C{ 1 H}NMR (101 MHz, dmso-d 6 ) δ = 22.86, 24.71 (CH 3 ), 28.39 (CH(CH 3 ) 2 ), 124.11, 126.87, 130.80, 133.05, 145.18 (arom.), 179.50 (C- Hg). ES-MS (m/z): 625 [M-Cl] +. Anal. calcd (%) for C 27 H 36 N 2 Cl 2 Hg (660.08): C 49.13, H 5.50, N 4.24; found: C 48.49, H 4.88, N 3.97. S2
(2b) Colourless solid. Yields: 50% route A, 63 % route B. 1 H NMR (400 MHz, dmso-d 6 ) δ = 1.77 (s, 12 H, CH 3 ), 2.45 (s, 6 H, CH 3 ), 7.01 (s, 4 H, arom), 8.04 (s, J H-Hg = 21 Hz, 2 H, imidazole ring). 13 C{ 1 H}NMR (101 MHz, dmso-d 6 ) δ = 16.75, 20.82 (CH 3 ), 126.18, 129.35, 132.32, 134.22, 139.97 (arom), 178.25 (C-Hg). ES-MS (m/z): 541 [M-Cl] +. Anal. calcd (%) for C 21 H 24 N 2 Cl 2 Hg (575.92): C 43.79, H 4.20, N 4.86; found: C 43.84, H 4.22, N 3.98. (2c) Yellow solid. Yield: 42% route A. 1 H NMR (600 MHz, dmso-d 6 ) δ = 3.99 (s, 6 H, CH 3 ). 13 C{ 1 H}NMR (151 MHz, dmso-d 6 ) δ = 37.14 (CH 3 ), 118.86 (imidazole ring), 177,66 (C-Hg). ES-MS (m/z): 493 [M-I] +. Anal. calcd (%) for C 5 H 6 N 2 Cl 2 I 2 Hg (619.42): C 9.70, H 0.98, N 4.52; found: C 9.20, H 1.08, N 4.59. (2d) Colourless solid. Yield: 45% route C. 1 H NMR (600 MHz, dmso-d 6 ) δ = 1.15 (d, J = 6.8 Hz, 12 H, CH 3 ), 1.30 (d, J = 6.8 Hz, 12 H, CH 3 ), 2.48 (sept, J = 6.8 Hz, 4 H, CH(CH 3 ) 2 ), 7.41 (d, J = 7.8 Hz, 4 H, m-c 6 H 3 ), 7.57 (t, J = 7.8 Hz, 2 H, p-c 6 H 3 ), 8.31 (s, J H-Hg = 25 Hz, 2 H, imidazole ring). 13 C{ 1 H}NMR (151 MHz, dmso-d 6 ) δ = 23.29, 24.83 (CH 3 ), 28.30 (CH(CH 3 ) 2 ), 124.29, 126.89, 130.92, 132.84, 144.96 (arom.), C-Hg not observed. ES-MS (m/z): 717 [M-I] +. Anal. calcd (%) for C 27 H 36 N 2 I 2 Hg (842.99): C 38.47, H 4.30, N 3.32; found: C 38.57, H 4.36, N 3.43. X-Ray crystallography Diffraction data for compounds 2a - 2c were collected at 150 K using an Oxford Diffraction Gemini E Ultra diffractometer, equipped with an EOS CCD area detector and a four-circle kappa goniometer. For the data collection the Mo source emitting graphite-monochromated Mo-Kα radiation (λ = 0.71073 Å) was used. Data integration, scaling and empirical absorption correction was carried out using the CrysAlis Pro program package. 3 The structures were solved using Direct Methods or Patterson Methods and refined by Full- Matrix-Least-Squares against F 2. The non-hydrogen atoms were refined anisotropically and hydrogen atoms were placed at idealized positions and refined using the riding model. All S3
calculations were carried out using the program Olex2. 4 Important crystallographic and refinement details are collected in Table S1. Table S1. Important crystallographic and refinement details for complexes 2a-2c. 2a 2b 2c Empirical formula C 27 H 36 N 2 HgCl 2 C 21 H 24 N 2 HgCl 2 C 10 H 12 Cl 4 Hg 2 I 4 N 4 Formula weight 660.07 575.91 1238.82 Crystal system Monoclinic Monoclinic Triclinic Space group C2/c P2 1 P-1 a (Å) 16.9962(6) 7.9365(4) 6.9536(7) b (Å) 9.0432(3) 15.8303(7) 8.8068(9) c (Å) 17.1910(5) 8.5548(4) 10.8660(9) α ( ) 90 90 66.416(9) β ( ) 90.741(3) 99.253(4) 83.452(8) γ ( ) 90 90 82.191(8) V (Å 3 ) 2642.03(15) 1060.82(9) 602.87(10) Z 4 2 1 D calc (g cm -3 ) 1.659 1.803 3.412 µ (mm -1 ) 6.045 7.513 18.285 F(000) 1304 556 540 θ range 3.35 to 29.38 3.25 to 58.6 2.96 to 29.38 Reflections collected 5893 5046 4595 Independent reflections 3024 3480 2795 Data/restraints/parameters 3024/0/150 3480/1/241 2795/0/111 GOF 0.870 0.980 1.069 S4
Final R indexes [I>2σ (I)] R 1 = 0.0219 wr 2 = 0.0394 Final R indexes [all data] R 1 = 0.0381 wr 2 = 0.0410 R 1 = 0.0288 wr 2 = 0.0620 R 1 = 0.0343 wr 2 = 0.0631 R 1 = 0.0340 wr 2 = 0.0752 R 1 = 0.0431 wr 2 = 0.0766 Largest diff. peak/hole (e Å -3 ) 1.103/-0.544 0.996/-1.086 1.462/-1.336 References (1) Hintermann, L. Beilstein J. Org. Chem. 2007, 3, 1. (2) Khramov, D. M.; Lynch, V. M.; Bielawski, C. W. Organometallics 2007, 26, 6042. (3) CrysAlis Pro 171.33.42, Oxford Diffraction Ltd., 2009. (4) Dolomanov, O. V.; Bourhis, L. J.; Gildea, R. J.; Howard, J. A. K.; Puschmann, H. J. Appl. Cryst. 2009, 42, 339. S5
1 H and 13 C NMR spectra of compounds 2a-2d in dmso-d 6. 2a 145.18 133.03 130.82 126.90 124.13 28.39 24.69 22.86 2 2 4 4 12 12 S6
2b 178.26 140.01 134.24 132.33 129.37 126.18 20.83 16.76 2 4 6 12 S7
2c 177.69 118.86 37.14 6 S8
2d 144.96 130.92 126.89 124.29 28.30 24.83 23.29 S9