Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104032986/hj1036sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270104032986/hj1036Isup2.hkl |
CCDC reference: 264777
An NMR tube was charged with Sm (6.0 mg, 0.040 mmol) and anhydrous THF (0.6 ml) in a glove-box. TiCl4 (8.8 µl, 0.080 mmol) was then introduced with a microsyringe. The colour of the solution immediately became yellow, indicating formation of the TiIV chloride tetrahydrofuran complex. The solution was stirred for 15 min and then thermostated at 333 K in a sand bath. After 12 h, dark-pink single crystals suitable for X-ray analysis were recovered as the sole crystalline product from the clear brown solution (8 mg, 20% yield).
H atoms were introduced in calculated positions as riding atoms, with C—H distances of 0.97 Å and with Uiso(H) values of 1.2Ueq(C).
Data collection: KappaCCD Server Software (Nonius, 1997); cell refinement: DENZO–SMN (Otwinowski & Minor, 1997); data reduction: DENZO–SMN (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1999); software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003).
Fig. 1. A view of compound (I), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. Primed atoms are at the symmetry position (-x, y, 1.5–z). |
[SmTi2Cl7O(C4H8O)6] | F(000) = 1892 |
Mr = 942.92 | Dx = 1.731 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
a = 10.1224 (4) Å | Cell parameters from 11856 reflections |
b = 34.3476 (16) Å | θ = 2.8–25.7° |
c = 10.9696 (4) Å | µ = 2.59 mm−1 |
β = 108.435 (3)° | T = 100 K |
V = 3618.2 (3) Å3 | Irregular, translucent dark pink |
Z = 4 | 0.23 × 0.19 × 0.12 mm |
Nonius KappaCCD area-detector diffractometer | 3384 independent reflections |
Radiation source: fine-focus sealed tube | 3155 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.035 |
ϕ scans | θmax = 25.7°, θmin = 2.8° |
Absorption correction: part of the refinement model (ΔF) (DELABS in PLATON; Spek, 2003) | h = −12→12 |
Tmin = 0.472, Tmax = 0.728 | k = −41→41 |
11856 measured reflections | l = −13→12 |
Refinement on F2 | Primary atom site location: patter |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.023 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.054 | H-atom parameters constrained |
S = 1.06 | w = 1/[σ2(Fo2) + (0.0144P)2 + 7.993P] where P = (Fo2 + 2Fc2)/3 |
3384 reflections | (Δ/σ)max = 0.001 |
187 parameters | Δρmax = 0.93 e Å−3 |
6 restraints | Δρmin = −0.95 e Å−3 |
[SmTi2Cl7O(C4H8O)6] | V = 3618.2 (3) Å3 |
Mr = 942.92 | Z = 4 |
Monoclinic, C2/c | Mo Kα radiation |
a = 10.1224 (4) Å | µ = 2.59 mm−1 |
b = 34.3476 (16) Å | T = 100 K |
c = 10.9696 (4) Å | 0.23 × 0.19 × 0.12 mm |
β = 108.435 (3)° |
Nonius KappaCCD area-detector diffractometer | 3384 independent reflections |
Absorption correction: part of the refinement model (ΔF) (DELABS in PLATON; Spek, 2003) | 3155 reflections with I > 2σ(I) |
Tmin = 0.472, Tmax = 0.728 | Rint = 0.035 |
11856 measured reflections |
R[F2 > 2σ(F2)] = 0.023 | 6 restraints |
wR(F2) = 0.054 | H-atom parameters constrained |
S = 1.06 | Δρmax = 0.93 e Å−3 |
3384 reflections | Δρmin = −0.95 e Å−3 |
187 parameters |
Experimental. The unit-cell parameters have been determined from 10 frames, then refined on all data. The crystal-to-detector distance was fixed to 30 mm. One-half of the diffraction sphere was scanned (90 frames, ϕ scans, 2° by frame). |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Structure solved by Patterson map interpretation and subsequent Fourier-difference synthesis. All non-hydrogen atoms were refined with anisotropic displacement parameters. The H atoms were introduced at calculated positions and were treated as riding atoms with an isotropic displacement parameter equal to 1.2 times that of the parent atom. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
Sm | 0.0000 | 0.317956 (5) | 0.7500 | 0.01553 (7) | |
Ti | 0.11227 (5) | 0.413820 (13) | 0.67121 (4) | 0.01413 (11) | |
Cl1 | 0.19553 (8) | 0.30847 (2) | 0.97409 (7) | 0.03111 (17) | |
Cl2 | 0.18901 (7) | 0.349295 (18) | 0.62322 (6) | 0.02101 (14) | |
Cl3 | 0.24466 (7) | 0.452407 (19) | 0.57216 (6) | 0.02106 (14) | |
Cl4 | 0.0000 | 0.46933 (2) | 0.7500 | 0.01523 (17) | |
O1 | 0.0000 | 0.38507 (7) | 0.7500 | 0.0142 (5) | |
O2 | −0.1165 (2) | 0.26149 (5) | 0.80837 (18) | 0.0225 (4) | |
O3 | 0.28789 (19) | 0.41877 (5) | 0.84123 (17) | 0.0193 (4) | |
O4 | −0.04677 (19) | 0.41585 (5) | 0.49025 (17) | 0.0180 (4) | |
C1 | −0.0463 (3) | 0.23190 (8) | 0.9010 (3) | 0.0292 (7) | |
H1A | 0.0458 | 0.2265 | 0.8957 | 0.035* | |
H1B | −0.0377 | 0.2401 | 0.9879 | 0.035* | |
C2 | −0.1391 (4) | 0.19659 (9) | 0.8632 (4) | 0.0371 (8) | |
H2A | −0.1247 | 0.1788 | 0.9350 | 0.045* | |
H2B | −0.1229 | 0.1829 | 0.7920 | 0.045* | |
C3 | −0.2840 (3) | 0.21429 (9) | 0.8244 (3) | 0.0342 (7) | |
H3A | −0.3149 | 0.2182 | 0.8987 | 0.041* | |
H3B | −0.3506 | 0.1979 | 0.7629 | 0.041* | |
C4 | −0.2658 (3) | 0.25301 (8) | 0.7643 (3) | 0.0287 (6) | |
H4A | −0.3001 | 0.2512 | 0.6713 | 0.034* | |
H4B | −0.3168 | 0.2734 | 0.7914 | 0.034* | |
C5 | 0.3867 (5) | 0.38849 (11) | 0.8945 (4) | 0.0646 (13) | |
H5A | 0.4365 | 0.3817 | 0.8351 | 0.077* | |
H5B | 0.3391 | 0.3654 | 0.9102 | 0.077* | |
C6 | 0.4859 (3) | 0.40306 (9) | 1.0175 (3) | 0.0275 (6) | |
H6A | 0.5814 | 0.3994 | 1.0187 | 0.033* | |
H6B | 0.4727 | 0.3894 | 1.0901 | 0.033* | |
C7 | 0.4529 (3) | 0.44639 (8) | 1.0223 (3) | 0.0241 (6) | |
H7A | 0.4039 | 0.4513 | 1.0838 | 0.029* | |
H7B | 0.5373 | 0.4619 | 1.0452 | 0.029* | |
C8 | 0.3613 (3) | 0.45524 (8) | 0.8866 (3) | 0.0215 (6) | |
H8A | 0.2961 | 0.4760 | 0.8861 | 0.026* | |
H8B | 0.4170 | 0.4629 | 0.8331 | 0.026* | |
C9 | −0.1040 (3) | 0.45283 (8) | 0.4284 (3) | 0.0208 (6) | |
H9A | −0.0295 | 0.4709 | 0.4307 | 0.025* | |
H9B | −0.1636 | 0.4647 | 0.4721 | 0.025* | |
C10 | −0.1874 (3) | 0.44287 (8) | 0.2900 (3) | 0.0235 (6) | |
H10A | −0.1383 | 0.4510 | 0.2314 | 0.028* | |
H10B | −0.2781 | 0.4553 | 0.2652 | 0.028* | |
C11 | −0.2017 (3) | 0.39867 (8) | 0.2907 (3) | 0.0263 (6) | |
H11A | −0.2818 | 0.3909 | 0.3155 | 0.032* | |
H11B | −0.2098 | 0.3877 | 0.2073 | 0.032* | |
C12 | −0.0676 (3) | 0.38654 (8) | 0.3902 (3) | 0.0247 (6) | |
H12A | −0.0758 | 0.3608 | 0.4232 | 0.030* | |
H12B | 0.0088 | 0.3866 | 0.3546 | 0.030* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Sm | 0.01647 (11) | 0.01384 (10) | 0.01407 (10) | 0.000 | 0.00167 (7) | 0.000 |
Ti | 0.0143 (2) | 0.0159 (2) | 0.0125 (2) | −0.00064 (18) | 0.00476 (18) | 0.00041 (17) |
Cl1 | 0.0307 (4) | 0.0346 (4) | 0.0195 (3) | 0.0107 (3) | −0.0042 (3) | −0.0028 (3) |
Cl2 | 0.0230 (3) | 0.0189 (3) | 0.0235 (3) | 0.0026 (3) | 0.0106 (3) | −0.0019 (2) |
Cl3 | 0.0191 (3) | 0.0266 (3) | 0.0199 (3) | −0.0019 (3) | 0.0095 (3) | 0.0032 (3) |
Cl4 | 0.0166 (4) | 0.0145 (4) | 0.0147 (4) | 0.000 | 0.0051 (3) | 0.000 |
O1 | 0.0161 (12) | 0.0149 (12) | 0.0109 (11) | 0.000 | 0.0034 (10) | 0.000 |
O2 | 0.0218 (10) | 0.0178 (9) | 0.0249 (10) | −0.0020 (8) | 0.0030 (8) | 0.0041 (8) |
O3 | 0.0165 (9) | 0.0194 (9) | 0.0186 (9) | −0.0012 (7) | 0.0008 (7) | 0.0013 (7) |
O4 | 0.0217 (10) | 0.0184 (9) | 0.0120 (8) | 0.0000 (7) | 0.0026 (7) | −0.0001 (7) |
C1 | 0.0321 (17) | 0.0234 (14) | 0.0305 (16) | 0.0053 (13) | 0.0076 (13) | 0.0101 (12) |
C2 | 0.045 (2) | 0.0229 (15) | 0.046 (2) | −0.0001 (14) | 0.0182 (16) | 0.0085 (14) |
C3 | 0.0356 (18) | 0.0286 (16) | 0.0401 (18) | −0.0086 (14) | 0.0144 (15) | 0.0014 (14) |
C4 | 0.0227 (15) | 0.0245 (14) | 0.0353 (17) | −0.0059 (12) | 0.0042 (13) | −0.0011 (13) |
C5 | 0.056 (2) | 0.0327 (18) | 0.070 (3) | 0.0102 (17) | −0.029 (2) | −0.0016 (18) |
C6 | 0.0193 (14) | 0.0327 (15) | 0.0268 (15) | −0.0027 (12) | 0.0022 (12) | 0.0098 (12) |
C7 | 0.0166 (14) | 0.0347 (16) | 0.0196 (14) | −0.0026 (12) | 0.0037 (11) | −0.0024 (12) |
C8 | 0.0203 (14) | 0.0212 (13) | 0.0209 (13) | −0.0056 (11) | 0.0034 (11) | −0.0019 (11) |
C9 | 0.0229 (14) | 0.0205 (13) | 0.0168 (13) | 0.0033 (11) | 0.0030 (11) | 0.0042 (10) |
C10 | 0.0231 (15) | 0.0312 (15) | 0.0145 (13) | −0.0006 (12) | 0.0033 (11) | 0.0033 (11) |
C11 | 0.0279 (16) | 0.0321 (16) | 0.0162 (13) | −0.0089 (13) | 0.0033 (11) | −0.0018 (11) |
C12 | 0.0351 (17) | 0.0211 (14) | 0.0159 (13) | −0.0032 (12) | 0.0051 (12) | −0.0041 (11) |
Sm—O1 | 2.305 (2) | C2—H2B | 0.9700 |
Sm—O2i | 2.4573 (18) | C3—C4 | 1.521 (4) |
Sm—O2 | 2.4573 (18) | C3—H3A | 0.9700 |
Sm—Cl1i | 2.6437 (7) | C3—H3B | 0.9700 |
Sm—Cl1 | 2.6437 (7) | C4—H4A | 0.9700 |
Sm—Cl2 | 2.9045 (7) | C4—H4B | 0.9700 |
Sm—Cl2i | 2.9045 (7) | C5—C6 | 1.491 (5) |
Sm—Ti | 3.6745 (5) | C5—H5A | 0.9700 |
Sm—Tii | 3.6745 (5) | C5—H5B | 0.9700 |
Ti—O1 | 1.9065 (13) | C6—C7 | 1.530 (4) |
Ti—O3 | 2.1379 (18) | C6—H6A | 0.9700 |
Ti—O4 | 2.1250 (18) | C6—H6B | 0.9700 |
Ti—Cl2 | 2.4599 (7) | C7—C8 | 1.515 (4) |
Ti—Cl3 | 2.3778 (7) | C7—H7A | 0.9700 |
Ti—Cl4 | 2.5089 (7) | C7—H7B | 0.9700 |
Ti—Tii | 3.2617 (9) | C8—H8A | 0.9700 |
Cl4—Tii | 2.5088 (7) | C8—H8B | 0.9700 |
O1—Tii | 1.9064 (13) | C9—C10 | 1.524 (4) |
O2—C1 | 1.454 (3) | C9—H9A | 0.9700 |
O2—C4 | 1.463 (3) | C9—H9B | 0.9700 |
O3—C5 | 1.433 (4) | C10—C11 | 1.525 (4) |
O3—C8 | 1.461 (3) | C10—H10A | 0.9700 |
O4—C12 | 1.455 (3) | C10—H10B | 0.9700 |
O4—C9 | 1.470 (3) | C11—C12 | 1.506 (4) |
C1—C2 | 1.510 (4) | C11—H11A | 0.9700 |
C1—H1A | 0.9700 | C11—H11B | 0.9700 |
C1—H1B | 0.9700 | C12—H12A | 0.9700 |
C2—C3 | 1.519 (5) | C12—H12B | 0.9700 |
C2—H2A | 0.9700 | ||
Cl1—Sm—Cl1i | 165.84 (3) | C3—C2—H2B | 111.3 |
Cl2—Sm—O1 | 68.247 (12) | H2A—C2—H2B | 109.2 |
Cl2—Sm—O2i | 74.03 (5) | C2—C3—C4 | 103.5 (3) |
O2—Sm—O2i | 75.77 (9) | C2—C3—H3A | 111.1 |
Cl2—Ti—Cl4 | 165.12 (3) | C4—C3—H3A | 111.1 |
Cl3—Ti—O1 | 177.10 (6) | C2—C3—H3B | 111.1 |
O3—Ti—O4 | 170.97 (7) | C4—C3—H3B | 111.1 |
Sm—Cl2—Ti | 86.04 (2) | H3A—C3—H3B | 109.0 |
Ti—Cl4—Tii | 81.09 (3) | O2—C4—C3 | 106.5 (2) |
Sm—O1—Ti | 121.19 (6) | O2—C4—H4A | 110.4 |
Ti—O1—Tii | 117.61 (12) | C3—C4—H4A | 110.4 |
Tii—O1—Sm | 121.19 (6) | O2—C4—H4B | 110.4 |
O1—Sm—O2i | 142.11 (5) | C3—C4—H4B | 110.4 |
O1—Sm—O2 | 142.12 (5) | H4A—C4—H4B | 108.6 |
O2i—Sm—O2 | 75.77 (9) | O3—C5—C6 | 108.0 (3) |
O1—Sm—Cl1i | 97.078 (17) | O3—C5—H5A | 110.1 |
O2i—Sm—Cl1i | 86.57 (5) | C6—C5—H5A | 110.1 |
O2—Sm—Cl1i | 82.26 (5) | O3—C5—H5B | 110.1 |
O1—Sm—Cl1 | 97.081 (17) | C6—C5—H5B | 110.1 |
O2i—Sm—Cl1 | 82.25 (5) | H5A—C5—H5B | 108.4 |
O2—Sm—Cl1 | 86.57 (5) | C5—C6—C7 | 105.4 (2) |
O2—Sm—Cl2 | 149.34 (5) | C5—C6—H6A | 110.7 |
Cl1i—Sm—Cl2 | 90.76 (2) | C7—C6—H6A | 110.7 |
Cl1—Sm—Cl2 | 94.48 (2) | C5—C6—H6B | 110.7 |
O1—Sm—Cl2i | 68.246 (12) | C7—C6—H6B | 110.7 |
O2i—Sm—Cl2i | 149.34 (5) | H6A—C6—H6B | 108.8 |
O2—Sm—Cl2i | 74.03 (5) | C8—C7—C6 | 103.5 (2) |
Cl1i—Sm—Cl2i | 94.48 (2) | C8—C7—H7A | 111.1 |
Cl1—Sm—Cl2i | 90.76 (2) | C6—C7—H7A | 111.1 |
Cl2—Sm—Cl2i | 136.49 (2) | C8—C7—H7B | 111.1 |
Ti—Sm—Tii | 52.697 (14) | C6—C7—H7B | 111.1 |
O1—Ti—O4 | 93.23 (5) | H7A—C7—H7B | 109.0 |
O1—Ti—O3 | 95.52 (5) | O3—C8—C7 | 104.5 (2) |
O4—Ti—Cl3 | 85.69 (5) | O3—C8—H8A | 110.9 |
O3—Ti—Cl3 | 85.47 (5) | C7—C8—H8A | 110.9 |
O1—Ti—Cl2 | 84.51 (6) | O3—C8—H8B | 110.9 |
O4—Ti—Cl2 | 91.54 (5) | C7—C8—H8B | 110.9 |
O3—Ti—Cl2 | 91.53 (5) | H8A—C8—H8B | 108.9 |
Cl3—Ti—Cl2 | 98.20 (3) | O4—C9—C10 | 106.2 (2) |
O1—Ti—Cl4 | 80.65 (6) | O4—C9—H9A | 110.5 |
O4—Ti—Cl4 | 90.29 (5) | C10—C9—H9A | 110.5 |
O3—Ti—Cl4 | 88.93 (5) | O4—C9—H9B | 110.5 |
Cl3—Ti—Cl4 | 96.66 (2) | C10—C9—H9B | 110.5 |
Tii—Ti—Sm | 63.652 (7) | H9A—C9—H9B | 108.7 |
C1—O2—C4 | 108.5 (2) | C9—C10—C11 | 104.0 (2) |
C1—O2—Sm | 124.43 (16) | C9—C10—H10A | 111.0 |
C4—O2—Sm | 126.98 (15) | C11—C10—H10A | 111.0 |
C5—O3—C8 | 105.6 (2) | C9—C10—H10B | 111.0 |
C5—O3—Ti | 125.34 (19) | C11—C10—H10B | 111.0 |
C8—O3—Ti | 123.93 (15) | H10A—C10—H10B | 109.0 |
C12—O4—C9 | 107.93 (19) | C12—C11—C10 | 102.3 (2) |
C12—O4—Ti | 124.64 (16) | C12—C11—H11A | 111.3 |
C9—O4—Ti | 122.06 (15) | C10—C11—H11A | 111.3 |
O2—C1—C2 | 104.2 (2) | C12—C11—H11B | 111.3 |
O2—C1—H1A | 110.9 | C10—C11—H11B | 111.3 |
C2—C1—H1A | 110.9 | H11A—C11—H11B | 109.2 |
O2—C1—H1B | 110.9 | O4—C12—C11 | 103.7 (2) |
C2—C1—H1B | 110.9 | O4—C12—H12A | 111.0 |
H1A—C1—H1B | 108.9 | C11—C12—H12A | 111.0 |
C1—C2—C3 | 102.5 (2) | O4—C12—H12B | 111.0 |
C1—C2—H2A | 111.3 | C11—C12—H12B | 111.0 |
C3—C2—H2A | 111.3 | H12A—C12—H12B | 109.0 |
C1—C2—H2B | 111.3 |
Symmetry code: (i) −x, y, −z+3/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
C1—H1A···Cl1ii | 0.97 | 2.82 | 3.651 (3) | 144 |
Symmetry code: (ii) −x+1/2, −y+1/2, −z+2. |
Experimental details
Crystal data | |
Chemical formula | [SmTi2Cl7O(C4H8O)6] |
Mr | 942.92 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 100 |
a, b, c (Å) | 10.1224 (4), 34.3476 (16), 10.9696 (4) |
β (°) | 108.435 (3) |
V (Å3) | 3618.2 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 2.59 |
Crystal size (mm) | 0.23 × 0.19 × 0.12 |
Data collection | |
Diffractometer | Nonius KappaCCD area-detector diffractometer |
Absorption correction | Part of the refinement model (ΔF) (DELABS in PLATON; Spek, 2003) |
Tmin, Tmax | 0.472, 0.728 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 11856, 3384, 3155 |
Rint | 0.035 |
(sin θ/λ)max (Å−1) | 0.610 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.023, 0.054, 1.06 |
No. of reflections | 3384 |
No. of parameters | 187 |
No. of restraints | 6 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.93, −0.95 |
Computer programs: KappaCCD Server Software (Nonius, 1997), DENZO–SMN (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 1999), SHELXTL and PLATON (Spek, 2003).
Sm—O1 | 2.305 (2) | Ti—O3 | 2.1379 (18) |
Sm—O2 | 2.4573 (18) | Ti—O4 | 2.1250 (18) |
Sm—Cl1 | 2.6437 (7) | Ti—Cl2 | 2.4599 (7) |
Sm—Cl2 | 2.9045 (7) | Ti—Cl3 | 2.3778 (7) |
Ti—O1 | 1.9065 (13) | Ti—Cl4 | 2.5089 (7) |
Cl1—Sm—Cl1i | 165.84 (3) | O3—Ti—O4 | 170.97 (7) |
Cl2—Sm—O1 | 68.247 (12) | Sm—Cl2—Ti | 86.04 (2) |
Cl2—Sm—O2i | 74.03 (5) | Ti—Cl4—Tii | 81.09 (3) |
O2—Sm—O2i | 75.77 (9) | Sm—O1—Ti | 121.19 (6) |
Cl2—Ti—Cl4 | 165.12 (3) | Ti—O1—Tii | 117.61 (12) |
Cl3—Ti—O1 | 177.10 (6) |
Symmetry code: (i) −x, y, −z+3/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
C1—H1A···Cl1ii | 0.97 | 2.82 | 3.651 (3) | 144 |
Symmetry code: (ii) −x+1/2, −y+1/2, −z+2. |
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There is an increasing interest in the use of the lanthanide metals as electron transfer reagents in organic transformations, such as the reductive dimerization of carbonyl compounds (Banik, 2002). The dualistic aspect of the latter reaction, including pinacol coupling and olefin reactions, has been extensively investigated in the case of low-valent titanium reagents, produced by TiCl4 or TiCl3 with reducers such as alkali metals, C8K, LiAlH4, Mg(Hg), Zn or Zn(Cu) (Ephritikhine & Villiers, 2004). On the other hand, the catalytic activity of the TiCl4–Sm system in propylene metathesis has been demonstrated (Imamura et al., 1989). As an extension of our studies on the McMurry reaction with the low-valent titanium reagent system TiCl4–Li(Hg) (Villiers & Ephritikhine, 2001), we have investigated the use of samarium metal instead of lithium amalgam as a reducing agent. In this context, we have isolated the title compound, (I), as the sole species from a tetrahydrofuran solution of the TiCl4–Sm couple at 333 K, the presence of the oxo ion being most likely due to adventitious traces of oxygen and/or water entering the NMR tube during heating. Compound (I) belongs to the family of mixed-metal species uniting lanthanide and transition metal ions. Only one complex with a µ3-oxo ion bridging two Ti atoms and one Ce atom is reported in the Cambridge Structural Database (CSD; Version 5.25; Allen, 2002), namely a tetranuclear Ce–Ti complex of 1:1 stoichiometry with additional µ,η2-pinacolate and isopropoxide bridging ligands (Hubert-Pfalzgraf et al., 1999). The only complex in the CSD that comprises both Sm and Ti atoms is the pentanuclear species [Sm4Ti(µ5-O)(µ3-OR)2(µ-OR)6(OR)6], (II), where R denotes isopropyl (Daniele et al., 1994). Compound (I) thus represents a rare example of an Sm–Ti complex and is the first trinuclear one. Whereas alkoxide or oxo–alkoxide complexes are frequent occurrences in such lanthanide–3 d transition mixed-metal compounds, (I) is a unique example of an oxychloride species.
The asymmetric unit in (I) contains half a molecule, the other half being generated by the binary crystallographic axis containing atoms Sm, O1 and Cl4 (Fig. 1). The three metal ions are bridged by a central trigonal µ3-oxo ion and by three µ2-chloro ions, the heptanuclear assemblage thus formed being planar, with an r.m.s. deviation of 0.012 Å. The whole assembly is analogous to one-half of the rhombus-shaped assemblage in the bis(µ3-oxo)-bridged Ce–Ti tetranuclear complex cited above (Hubert-Pfalzgraf et al., 1999), with atom Cl4 in (I) replacing the second µ3-oxo ion, and the other chloride ions and THF moieties in (I) replacing the µ,η2-pinacolate and isopropoxide ligands.
The Sm atom is bound to four chloride ions, two of them terminal (Cl1 and Cl1') and the others bridging (Cl2 and Cl2') [primed atoms are at the symmetry position (-x, y, 1.5 − z)]. The Sm—Cl bond lengths (Table 1) are in reasonable agreement with the SmIII—Cl bond lengths reported in the CSD [2.65 (4) Å for terminal and 2.80 (6) Å for bridging chloride ions]. The Sm—O1 bond length in (I) [2.305 (2) Å] is larger than that in the only µ3-oxo samarium complex reported [2.211 (8) Å; Hosmane et al., 1996], whereas the Sm—O(THF) bond length in (I) [2.4573 (18) Å] agrees with the mean value from the CSD [2.47 (6) Å]. The seven-coordinate Sm atom is in a distorted pentagonal bipyramidal environment, with the terminal chloride atoms in axial positions. In (II), the Sm atoms are six-coordinate.
The two crystallographically equivalent Ti atoms are bound to one terminal and two bridging chloride ions, with Ti—Cl bond lengths of 2.3778 (7) and 2.48 (2) Å (mean value), respectively, both in good agreement with the corresponding mean values for TiIII ions from the CSD [2.35 (4) and 2.49 (6) Å, respectively]. The Ti—O(oxo) bond length [1.9065 (13) Å] is smaller than the mean value [1.968 (6) Å] for the µ3-oxo–TiIII complexes in the CSD. The Ti atoms are further bound to two THF molecules each, with a mean bond length of 2.131 (6) Å [the mean TiIII—O(THF) bond length from the CSD is 2.16 (7) Å]. The Ti atoms are thus six-coordinate and their environment is distorted octahedral. Each of the three polyhedra associated with the three metal ions shares one edge with each of the two others.
The central µ3-oxo ion is trigonal, with a difference of only 3.6° between the Sm—O1—Ti and Ti—O1—Ti' angles, whereas the angles around the two bridging chloride ions differ by about 5°, in keeping with a Ti···Ti' distance [3.2617 (9) Å] smaller than the Sm···Ti distance [3.6745 (5) Å].
Apart from van der Waals interactions, the packing is probably stabilized by a weak C1—H···Cl1" hydrogen bond [doubly primed atoms are at the symmetry position (0.5 − x, 0.5 − y, 2 − z)], which, together with the symmetrical C1"—H"···Cl1 bond, ensures dimerization around a symmetry centre (Table 2).