Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104030471/bm1598sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270104030471/bm1598Isup2.hkl |
CCDC reference: 263030
The title compound was prepared by reaction of 1,1'-dimethyl-3,3'-methylenediimidazolium dibromide (Muehlhofer, Strassner, Herdtweck & Herrmann, 2002) with cobalt(II) chloride hexahydrate in refluxing tetrahydrofuran/ethanol (2:1) for 10 h. The resulting light-blue precipitate was isolated by filtration and washed with tetrahydrofuran (yield 73%). Elemental analysis revealed a formulation of a 1:1 mixture of the tetrachloro- and corresponding tetrabromocobaltate compounds. Analysis calculated for C9H14Br2Cl2CoN4: C 23.10, H 3.02, N 11.97%; found: C 23.15, H 3.01, N 11.98%. Crystals of (I) could be obtained selectively by slow diffusion of tetrahydrofuran into a solution of the product in dimethylsulfoxide.
From the Co-editor: Please check corrected text below. One methyl group is disordered over two sets of positions, with occupancies of 0.61 (3) and 0.39 (3). Methyl H atoms were located from difference Fourier syntheses and refined as part of rigid rotating groups, with C—H = 0.98 Å and Uiso(H) = 1.5Ueq(C). Other H atoms were placed in calculated positions and refined using a riding model, with methylene and aromatic C—H distances of 0.99 and 0.95 Å, respectively, and Uiso(H) = 1.2Ueq(C).
Data collection: KappaCCD Server Software (Nonius, 2001); cell refinement: DENZO (Nonius, 2001); data reduction: DENZO; program(s) used to solve structure: SIR92 (Altomare, 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1998); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: PLATON.
(C9H14N4)[CoCl4] | F(000) = 1528 |
Mr = 378.97 | Dx = 1.623 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 3026 reflections |
a = 15.2885 (1) Å | θ = 1.5–25.2° |
b = 7.1995 (1) Å | µ = 1.78 mm−1 |
c = 28.2539 (3) Å | T = 173 K |
β = 94.0770 (4)° | Plate, light blue |
V = 3102.02 (6) Å3 | 0.38 × 0.20 × 0.05 mm |
Z = 8 |
Nonius KappaCCD area-detector diffractometer | 2784 independent reflections |
Radiation source: NONIUS FR591 rotating anode | 2509 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.044 |
Detector resolution: 18 pixels mm-1 | θmax = 25.2°, θmin = 1.5° |
ϕ and ω rotation scans | h = −18→18 |
Absorption correction: multi-scan (DENZO; Nonius, 2001) | k = −8→8 |
Tmin = 0.562, Tmax = 0.916 | l = −33→33 |
32195 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.026 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.067 | H-atom parameters constrained |
S = 1.05 | Weighting scheme based on measured s.u.'s w = 1/[σ2(Fo2) + (Fo2) + (0.029P)2 + 4.883P] where P = (Fo2 + 2Fc2)/3 |
2784 reflections | (Δ/σ)max < 0.001 |
166 parameters | Δρmax = 0.31 e Å−3 |
0 restraints | Δρmin = −0.28 e Å−3 |
(C9H14N4)[CoCl4] | V = 3102.02 (6) Å3 |
Mr = 378.97 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 15.2885 (1) Å | µ = 1.78 mm−1 |
b = 7.1995 (1) Å | T = 173 K |
c = 28.2539 (3) Å | 0.38 × 0.20 × 0.05 mm |
β = 94.0770 (4)° |
Nonius KappaCCD area-detector diffractometer | 2784 independent reflections |
Absorption correction: multi-scan (DENZO; Nonius, 2001) | 2509 reflections with I > 2σ(I) |
Tmin = 0.562, Tmax = 0.916 | Rint = 0.044 |
32195 measured reflections |
R[F2 > 2σ(F2)] = 0.026 | 0 restraints |
wR(F2) = 0.067 | H-atom parameters constrained |
S = 1.05 | Δρmax = 0.31 e Å−3 |
2784 reflections | Δρmin = −0.28 e Å−3 |
166 parameters |
Experimental. Diffractometer operator E. Herdtweck scanspeed 2 x 40 s per film repetition 1 dx 40 992 films measured in 8 data sets set 1: phi-scan with delta_phi = 1.0 set 2 to 8: omega-scans with delta_omega = 1.0 |
Refinement. The crystal was fixed in a capillary with perfluorinated ether and transferred to the diffractometer. Preliminary examination and data collection were carried out on an area detecting system (Nonius, MACH3, κ-CCD) at the window of a rotating anode (Nonius, FR951) and graphite monochromated Mo Kα radiation (λ = 0.71073 Å). Eight data sets were measured in rotation scan modus with Δϕ / Δω = 1.0°. Raw data were corrected for Lorentz, polarization, and, arising from the scaling procedure, for latent decay and absorption effects. The structure was solved by a combination of direct methods and difference Fourier syntheses. All non-hydrogen atoms were refined with anisotropic displacement parameters. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
N1 | 0.16816 (12) | 0.5446 (3) | 0.20446 (6) | 0.0304 (6) | |
N2 | 0.12457 (12) | 0.7854 (3) | 0.16470 (6) | 0.0294 (6) | |
N3 | 0.06209 (12) | 0.8651 (3) | 0.08664 (7) | 0.0294 (6) | |
N4 | −0.04959 (12) | 0.7799 (3) | 0.04123 (7) | 0.0316 (6) | |
C1 | 0.18091 (15) | 0.6450 (3) | 0.16677 (8) | 0.0305 (7) | |
C2 | 0.10120 (17) | 0.6210 (4) | 0.22733 (9) | 0.0474 (9) | |
C3 | 0.07359 (18) | 0.7708 (4) | 0.20265 (9) | 0.0513 (10) | |
C4 | 0.2162 (2) | 0.3761 (4) | 0.21968 (11) | 0.0534 (10) | |
C5 | 0.11583 (16) | 0.9289 (3) | 0.12812 (9) | 0.0373 (8) | |
C6 | −0.02461 (15) | 0.8422 (3) | 0.08418 (8) | 0.0302 (7) | |
C7 | 0.02299 (17) | 0.7633 (4) | 0.01542 (8) | 0.0381 (8) | |
C8 | 0.09285 (16) | 0.8151 (3) | 0.04368 (8) | 0.0369 (8) | |
C9 | −0.13979 (17) | 0.7331 (4) | 0.02414 (10) | 0.0452 (9) | |
Co | 0.40632 (2) | 0.82778 (4) | 0.12818 (1) | 0.0302 (1) | |
Cl1 | 0.54288 (4) | 0.87927 (8) | 0.10327 (2) | 0.0319 (2) | |
Cl2 | 0.31724 (4) | 0.69706 (9) | 0.06859 (2) | 0.0369 (2) | |
Cl3 | 0.33625 (4) | 1.08951 (8) | 0.14925 (2) | 0.0396 (2) | |
Cl4 | 0.41672 (4) | 0.62947 (9) | 0.19100 (2) | 0.0454 (2) | |
H11 | 0.22350 | 0.62110 | 0.14460 | 0.0370* | |
H21 | 0.07840 | 0.57610 | 0.25560 | 0.0570* | |
H31 | 0.02740 | 0.85180 | 0.21000 | 0.0620* | |
H41 | 0.23280 | 0.38350 | 0.25380 | 0.0800* | |
H42 | 0.26910 | 0.36510 | 0.20220 | 0.0800* | |
H43 | 0.17880 | 0.26720 | 0.21320 | 0.0800* | |
H51 | 0.08880 | 1.04100 | 0.14120 | 0.0450* | |
H52 | 0.17470 | 0.96350 | 0.11860 | 0.0450* | |
H61 | −0.06200 | 0.86640 | 0.10890 | 0.0360* | |
H71 | 0.02350 | 0.72270 | −0.01650 | 0.0460* | |
H81 | 0.15220 | 0.81700 | 0.03570 | 0.0440* | |
H91 | −0.14560 | 0.74030 | −0.01060 | 0.0680* | 0.61 (3) |
H92 | −0.18050 | 0.82100 | 0.03740 | 0.0680* | 0.61 (3) |
H93 | −0.15350 | 0.60680 | 0.03420 | 0.0680* | 0.61 (3) |
H94 | −0.17410 | 0.70510 | 0.05130 | 0.0680* | 0.39 (3) |
H95 | −0.13920 | 0.62440 | 0.00330 | 0.0680* | 0.39 (3) |
H96 | −0.16620 | 0.83860 | 0.00650 | 0.0680* | 0.39 (3) |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0310 (10) | 0.0342 (10) | 0.0261 (10) | 0.0020 (8) | 0.0036 (8) | 0.0012 (8) |
N2 | 0.0273 (10) | 0.0339 (11) | 0.0263 (10) | 0.0015 (8) | −0.0028 (8) | −0.0008 (8) |
N3 | 0.0272 (10) | 0.0317 (10) | 0.0290 (10) | 0.0003 (8) | −0.0003 (8) | 0.0053 (8) |
N4 | 0.0315 (10) | 0.0332 (10) | 0.0292 (10) | 0.0018 (8) | −0.0040 (8) | 0.0020 (8) |
C1 | 0.0291 (12) | 0.0314 (12) | 0.0317 (12) | 0.0008 (10) | 0.0064 (10) | −0.0020 (10) |
C2 | 0.0389 (15) | 0.074 (2) | 0.0303 (13) | 0.0199 (14) | 0.0105 (11) | 0.0097 (13) |
C3 | 0.0425 (15) | 0.079 (2) | 0.0335 (14) | 0.0303 (15) | 0.0106 (12) | 0.0062 (14) |
C4 | 0.067 (2) | 0.0413 (15) | 0.0534 (18) | 0.0176 (14) | 0.0153 (15) | 0.0138 (13) |
C5 | 0.0360 (14) | 0.0336 (13) | 0.0404 (14) | −0.0029 (11) | −0.0106 (11) | 0.0054 (11) |
C6 | 0.0293 (12) | 0.0320 (12) | 0.0295 (12) | −0.0002 (10) | 0.0028 (10) | 0.0010 (9) |
C7 | 0.0438 (15) | 0.0444 (14) | 0.0267 (12) | 0.0068 (12) | 0.0071 (11) | 0.0019 (11) |
C8 | 0.0313 (13) | 0.0468 (15) | 0.0334 (13) | 0.0062 (11) | 0.0075 (10) | 0.0086 (11) |
C9 | 0.0375 (15) | 0.0505 (16) | 0.0455 (15) | −0.0057 (12) | −0.0108 (12) | −0.0032 (13) |
Co | 0.0299 (2) | 0.0333 (2) | 0.0274 (2) | 0.0024 (1) | 0.0019 (1) | −0.0016 (1) |
Cl1 | 0.0280 (3) | 0.0334 (3) | 0.0343 (3) | −0.0028 (2) | 0.0018 (2) | −0.0004 (2) |
Cl2 | 0.0283 (3) | 0.0509 (4) | 0.0315 (3) | −0.0004 (3) | 0.0023 (2) | −0.0093 (3) |
Cl3 | 0.0387 (3) | 0.0367 (3) | 0.0443 (3) | 0.0039 (3) | 0.0087 (3) | −0.0084 (3) |
Cl4 | 0.0487 (4) | 0.0520 (4) | 0.0366 (3) | 0.0167 (3) | 0.0099 (3) | 0.0152 (3) |
Co—Cl1 | 2.2805 (7) | C1—H11 | 0.95 |
Co—Cl2 | 2.2911 (7) | C2—H21 | 0.95 |
Co—Cl3 | 2.2679 (7) | C3—H31 | 0.95 |
Co—Cl4 | 2.2746 (7) | C4—H43 | 0.98 |
N1—C4 | 1.467 (4) | C4—H41 | 0.98 |
N1—C1 | 1.313 (3) | C4—H42 | 0.98 |
N1—C2 | 1.365 (3) | C5—H52 | 0.99 |
N2—C5 | 1.461 (3) | C5—H51 | 0.99 |
N2—C3 | 1.374 (3) | C6—H61 | 0.95 |
N2—C1 | 1.327 (3) | C7—H71 | 0.95 |
N3—C6 | 1.333 (3) | C8—H81 | 0.95 |
N3—C8 | 1.380 (3) | C9—H95 | 0.98 |
N3—C5 | 1.457 (3) | C9—H96 | 0.98 |
N4—C6 | 1.324 (3) | C9—H94 | 0.98 |
N4—C7 | 1.376 (3) | C9—H91 | 0.98 |
N4—C9 | 1.468 (3) | C9—H92 | 0.98 |
C2—C3 | 1.336 (4) | C9—H93 | 0.98 |
C7—C8 | 1.340 (3) | ||
Co···C1 | 3.915 (2) | C6···Cl3vi | 3.431 (2) |
Co···C6i | 3.882 (2) | C6···Cl1vi | 3.519 (2) |
Co···H11 | 3.2289 | C6···Coix | 3.882 (2) |
Co···H61i | 3.4063 | C6···Cl2ix | 3.524 (2) |
Co···H71ii | 3.4236 | C7···C7xi | 3.575 (4) |
Co···H93iii | 3.4025 | C7···Cl2ii | 3.536 (3) |
Cl1···C1iii | 3.285 (2) | C7···Cl1ii | 3.582 (2) |
Cl1···C5i | 3.484 (2) | C8···Cl2 | 3.556 (3) |
Cl1···C6iii | 3.519 (2) | C8···Cl2ii | 3.547 (2) |
Cl1···C7ii | 3.582 (2) | C9···Cl2ix | 3.645 (3) |
Cl2···C8 | 3.556 (3) | C9···C9xii | 3.553 (4) |
Cl2···C6i | 3.524 (2) | C1···H41iv | 3.0503 |
Cl2···C7ii | 3.536 (3) | C2···H21viii | 2.8399 |
Cl2···C1 | 3.606 (2) | C3···H21viii | 3.0242 |
Cl2···C9i | 3.645 (3) | C3···H31viii | 3.0589 |
Cl2···C8ii | 3.547 (2) | C9···H96xii | 3.0739 |
Cl3···C6iii | 3.431 (2) | H11···Co | 3.2289 |
Cl3···C2iv | 3.557 (3) | H11···H42 | 2.5239 |
Cl3···C5 | 3.573 (3) | H11···Cl2 | 2.7208 |
Cl3···C4v | 3.479 (3) | H11···Cl4 | 3.1461 |
Cl4···C3i | 3.524 (3) | H21···C2viii | 2.8399 |
Cl4···C1 | 3.623 (2) | H21···C3viii | 3.0242 |
Cl1···H51i | 2.7323 | H21···H21viii | 2.3956 |
Cl1···H71ii | 2.6880 | H21···Cl3vii | 2.9052 |
Cl2···H11 | 2.7208 | H31···C3viii | 3.0589 |
Cl2···H81ii | 3.0177 | H31···H31viii | 2.4658 |
Cl2···H81 | 2.7645 | H31···Cl4ix | 2.6493 |
Cl2···H96i | 3.1409 | H41···C1vii | 3.0503 |
Cl2···H93iii | 3.1477 | H42···Cl4 | 2.9863 |
Cl2···H92i | 2.8482 | H42···Cl3x | 2.7290 |
Cl2···H71ii | 2.9896 | H42···H11 | 2.5239 |
Cl3···H52 | 2.7146 | H51···Cl1ix | 2.7323 |
Cl3···H94iii | 2.8834 | H51···Cl4ix | 3.1358 |
Cl3···H61iii | 2.8188 | H52···Cl3 | 2.7146 |
Cl3···H21iv | 2.9053 | H52···H81 | 2.5695 |
Cl3···H42v | 2.7290 | H61···H94 | 2.5569 |
Cl4···H11 | 3.1461 | H61···Coix | 3.4063 |
Cl4···H42 | 2.9863 | H61···Cl4ix | 3.0300 |
Cl4···H61i | 3.0300 | H61···Cl3vi | 2.8188 |
Cl4···H31i | 2.6493 | H71···Cl1ii | 2.6880 |
Cl4···H51i | 3.1358 | H71···Coii | 3.4236 |
C1···Co | 3.915 (2) | H71···Cl2ii | 2.9896 |
C1···Cl2 | 3.606 (2) | H81···H52 | 2.5695 |
C1···Cl4 | 3.623 (2) | H81···Cl2 | 2.7645 |
C1···Cl1vi | 3.285 (2) | H81···Cl2ii | 3.0177 |
C2···Cl3vii | 3.557 (3) | H92···Cl2ix | 2.8482 |
C2···C2viii | 3.432 (4) | H93···Covi | 3.4025 |
C2···C4iv | 3.580 (4) | H93···Cl2vi | 3.1477 |
C3···Cl4ix | 3.524 (3) | H94···H61 | 2.5569 |
C4···C2vii | 3.580 (4) | H94···Cl3vi | 2.8834 |
C4···Cl3x | 3.479 (3) | H96···Cl2ix | 3.1409 |
C5···Cl1ix | 3.484 (2) | H96···C9xii | 3.0739 |
C5···Cl3 | 3.573 (3) | ||
Cl1—Co—Cl2 | 110.45 (2) | C2—C3—H31 | 126.40 |
Cl1—Co—Cl3 | 113.94 (2) | N1—C4—H41 | 109.42 |
Cl1—Co—Cl4 | 109.15 (2) | H41—C4—H43 | 109.51 |
Cl2—Co—Cl3 | 105.49 (2) | H42—C4—H43 | 109.42 |
Cl2—Co—Cl4 | 108.69 (2) | H41—C4—H42 | 109.54 |
Cl3—Co—Cl4 | 108.95 (2) | N1—C4—H42 | 109.45 |
C1—N1—C2 | 108.8 (2) | N1—C4—H43 | 109.49 |
C1—N1—C4 | 126.4 (2) | N2—C5—H51 | 109.39 |
C2—N1—C4 | 124.9 (2) | N3—C5—H52 | 109.42 |
C1—N2—C3 | 108.1 (2) | N2—C5—H52 | 109.34 |
C1—N2—C5 | 126.62 (19) | N3—C5—H51 | 109.31 |
C3—N2—C5 | 125.3 (2) | H51—C5—H52 | 107.95 |
C5—N3—C8 | 125.57 (19) | N4—C6—H61 | 125.92 |
C5—N3—C6 | 125.7 (2) | N3—C6—H61 | 125.98 |
C6—N3—C8 | 108.76 (19) | N4—C7—H71 | 126.31 |
C6—N4—C7 | 108.92 (19) | C8—C7—H71 | 126.31 |
C6—N4—C9 | 125.6 (2) | N3—C8—H81 | 126.55 |
C7—N4—C9 | 125.5 (2) | C7—C8—H81 | 126.62 |
N1—C1—N2 | 108.8 (2) | N4—C9—H94 | 109.40 |
N1—C2—C3 | 107.3 (2) | N4—C9—H95 | 109.42 |
N2—C3—C2 | 107.1 (2) | H92—C9—H93 | 109.48 |
N2—C5—N3 | 111.36 (18) | H94—C9—H95 | 109.53 |
N3—C6—N4 | 108.1 (2) | H94—C9—H96 | 109.48 |
N4—C7—C8 | 107.4 (2) | H95—C9—H96 | 109.55 |
N3—C8—C7 | 106.8 (2) | N4—C9—H96 | 109.45 |
N1—C1—H11 | 125.65 | H91—C9—H92 | 109.48 |
N2—C1—H11 | 125.58 | H91—C9—H93 | 109.48 |
C3—C2—H21 | 126.29 | N4—C9—H91 | 109.47 |
N1—C2—H21 | 126.38 | N4—C9—H92 | 109.47 |
N2—C3—H31 | 126.54 | N4—C9—H93 | 109.45 |
C2—N1—C1—N2 | 0.5 (3) | C8—N3—C5—N2 | −105.8 (3) |
C4—N1—C1—N2 | 179.6 (2) | C5—N3—C6—N4 | −179.0 (2) |
C1—N1—C2—C3 | −0.1 (3) | C8—N3—C6—N4 | −0.1 (3) |
C4—N1—C2—C3 | −179.2 (2) | C5—N3—C8—C7 | 179.3 (2) |
C3—N2—C1—N1 | −0.7 (3) | C6—N3—C8—C7 | 0.5 (3) |
C5—N2—C1—N1 | −179.2 (2) | C7—N4—C6—N3 | −0.3 (3) |
C1—N2—C3—C2 | 0.6 (3) | C9—N4—C6—N3 | 178.8 (2) |
C5—N2—C3—C2 | 179.2 (2) | C6—N4—C7—C8 | 0.6 (3) |
C1—N2—C5—N3 | 82.7 (3) | C9—N4—C7—C8 | −178.5 (2) |
C3—N2—C5—N3 | −95.6 (3) | N1—C2—C3—N2 | −0.3 (3) |
C6—N3—C5—N2 | 72.9 (3) | N4—C7—C8—N3 | −0.6 (3) |
Symmetry codes: (i) x+1/2, y−1/2, z; (ii) −x+1/2, −y+3/2, −z; (iii) x+1/2, y+1/2, z; (iv) −x+1/2, y+1/2, −z+1/2; (v) x, y+1, z; (vi) x−1/2, y−1/2, z; (vii) −x+1/2, y−1/2, −z+1/2; (viii) −x, y, −z+1/2; (ix) x−1/2, y+1/2, z; (x) x, y−1, z; (xi) −x, −y+2, −z; (xii) −x−1/2, −y+3/2, −z. |
D—H···A | D—H | H···A | D···A | D—H···A |
C6—H61···Cl3vi | 0.95 | 2.82 | 3.431 (2) | 123 |
C1—H11···Cl2 | 0.95 | 2.72 | 3.606 (2) | 155 |
C2—H21···Cl3vii | 0.95 | 2.91 | 3.557 (3) | 127 |
C3—H31···Cl4ix | 0.95 | 2.65 | 3.524 (3) | 153 |
C4—H42···Cl3x | 0.98 | 2.73 | 3.479 (3) | 134 |
C5—H51···Cl1ix | 0.99 | 2.73 | 3.484 (2) | 133 |
C5—H52···Cl3 | 0.99 | 2.71 | 3.573 (3) | 145 |
C7—H71···Cl1ii | 0.95 | 2.69 | 3.582 (2) | 157 |
C8—H81···Cl2 | 0.95 | 2.76 | 3.556 (3) | 141 |
Symmetry codes: (ii) −x+1/2, −y+3/2, −z; (vi) x−1/2, y−1/2, z; (vii) −x+1/2, y−1/2, −z+1/2; (ix) x−1/2, y+1/2, z; (x) x, y−1, z. |
Experimental details
Crystal data | |
Chemical formula | (C9H14N4)[CoCl4] |
Mr | 378.97 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 173 |
a, b, c (Å) | 15.2885 (1), 7.1995 (1), 28.2539 (3) |
β (°) | 94.0770 (4) |
V (Å3) | 3102.02 (6) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 1.78 |
Crystal size (mm) | 0.38 × 0.20 × 0.05 |
Data collection | |
Diffractometer | Nonius KappaCCD area-detector diffractometer |
Absorption correction | Multi-scan (DENZO; Nonius, 2001) |
Tmin, Tmax | 0.562, 0.916 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 32195, 2784, 2509 |
Rint | 0.044 |
(sin θ/λ)max (Å−1) | 0.600 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.026, 0.067, 1.05 |
No. of reflections | 2784 |
No. of parameters | 166 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.31, −0.28 |
Computer programs: KappaCCD Server Software (Nonius, 2001), DENZO (Nonius, 2001), DENZO, SIR92 (Altomare, 1994), SHELXL97 (Sheldrick, 1998), PLATON (Spek, 2003), PLATON.
Co—Cl1 | 2.2805 (7) | N2—C1 | 1.327 (3) |
Co—Cl2 | 2.2911 (7) | N3—C6 | 1.333 (3) |
Co—Cl3 | 2.2679 (7) | N3—C8 | 1.380 (3) |
Co—Cl4 | 2.2746 (7) | N3—C5 | 1.457 (3) |
N1—C4 | 1.467 (4) | N4—C6 | 1.324 (3) |
N1—C1 | 1.313 (3) | N4—C7 | 1.376 (3) |
N1—C2 | 1.365 (3) | N4—C9 | 1.468 (3) |
N2—C5 | 1.461 (3) | C2—C3 | 1.336 (4) |
N2—C3 | 1.374 (3) | C7—C8 | 1.340 (3) |
Cl1—Co—Cl2 | 110.45 (2) | Cl2—Co—Cl3 | 105.49 (2) |
Cl1—Co—Cl3 | 113.94 (2) | Cl2—Co—Cl4 | 108.69 (2) |
Cl1—Co—Cl4 | 109.15 (2) | Cl3—Co—Cl4 | 108.95 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
C1—H11···Cl2 | 0.95 | 2.72 | 3.606 (2) | 155 |
C2—H21···Cl3i | 0.95 | 2.91 | 3.557 (3) | 127 |
C3—H31···Cl4ii | 0.95 | 2.65 | 3.524 (3) | 153 |
C4—H42···Cl3iii | 0.98 | 2.73 | 3.479 (3) | 134 |
C5—H51···Cl1ii | 0.99 | 2.73 | 3.484 (2) | 133 |
C5—H52···Cl3 | 0.99 | 2.71 | 3.573 (3) | 145 |
C7—H71···Cl1iv | 0.95 | 2.69 | 3.582 (2) | 157 |
C8—H81···Cl2 | 0.95 | 2.76 | 3.556 (3) | 141 |
Symmetry codes: (i) −x+1/2, y−1/2, −z+1/2; (ii) x−1/2, y+1/2, z; (iii) x, y−1, z; (iv) −x+1/2, −y+3/2, −z. |
Metal complexes of N-heterocyclic carbenes (NHC) have been shown to be extremely versatile and stable catalysts for a wide range of reactions (Herrmann, 2002). In particular, chelating NHC complexes have proved to have enhanced thermal stability, leading to remarkable catalytic properties. For instance, bridged palladium triscarbene complexes have been successfully applied in various catalytic reactions (e.g. C—C coupling reactions; Herrmann et al., 1995, 1998), and in particular to C—H activation (Muehlhofer, Strassner & Herrmann, 2002). A convenient synthesis of bridged NHC complexes is the conversion of basic metal precursors, such as palladium(II) acetate, with a bridged imidazolium salt (Herrmann et al., 1998). Here, we report the structural characterization of a methylene-bridged imidazolium salt with a tetrachlorocobaltate counteranion, (I). Previously, only a few reports of solid-state structures of imidazolium salts containing transition metal–halide anions have been published (Dullius et al., 1998; Ortwerth et al., 1998; Hasan et al., 1999, 2001), including the related 1-ethyl-3-methylimidazolium tetrachlorocobaltate (Hitchcock et al., 1993). They all show short contacts between imidazolium H atoms and the halide atoms of the anion, due to ionic interactions.
The structure of (I) is depicted in Fig. 1, and selected geometric parameters are given in Table 1. For steric reasons, the N—CH—N unit in the two imidazole moieties points in opposite directions. The N1—C1 and N2—C1 (and N3—C6 and N4—C6) bonds are almost identical, which indicates delocalization within these bonds. The dihedral angle between the imidazole rings is 72.97 (9)°. The Co atom of the counteranion is surrounded by four Cl− ions in a tetrahedral fashion, with bond lengths ranging from 2.2680 (7) to 2.2907 (7) Å. As previously observed for analogous compounds, several short contacts are formed between C—H bonds and the Cl− of the anion. In the case of (I), they are established by imidazolium ring H atoms, as well as by both H atoms of the methylene bridge and one H atom of the methyl group (bond distances in Table 2). This shows a possible polarization of all C—H bonds adjacent to an N atom in an imidazolium salt, and not only of the central C—H bond in the N—CH—N unit, which is deprotonated during the formation of metal–NHC complexes.
From the Co-editor: Please check important changes in the following paragraph. As can be seen from Fig. 2 and Table 2, the most acidic H atoms take part in C—H···Cl contacts, which build up a bilayer structure parallel to the ab plane. Contacts such as C2—H21···Cl3iv [symmetry code: (iv) 1/2 − x, y − 1/2, 1/2 − z], which are longer but still within the sum of the relevant van der Waals radii (2.95 Å; Reference?), connect these layers into a three-dimensional network.
From the Co-editor: Please provide a reference for the source of the van der Waals radii.