metal-organic compounds
Chloridobis{N-[(dimethylamino)dimethylsilyl]-2,6-dimethylanilido-κ2N,N′}titanium(III)
aDepartment of Chemistry, Taiyuan Teachers College, Taiyuan 030031, People's Republic of China
*Correspondence e-mail: sdbai@sxu.edu.cn
In the monomeric title titanium(III) compound, [Ti(C12H21N2Si)2Cl], the metal atom is surrounded by two N–silylated anilide ligands in an N,N′′-chelating mode. The two ends of the N—Si—N chelating unit exhibit different affinity to the metal center. The Ti—Namine bond is longer than the Ti—Nanilide bond by about 0.29 Å. The two ligands are arranged trans to each other and the molecule demonstrates a pseudo-twofold rotation along the axis of the Ti—Cl bond. The five–coordinate Ti atom demonstrates a highly distorted trigonal-bipyramidal geometry.
Related literature
For related titanium compounds, see: Ovchinnikov et al. (1993); Chomitz et al. (2008). For amido titanium compounds as olefin polymerization catalyts, see: Alesso et al. (2008); Oakes et al. (2004); Tabernero et al. (2009). For catalytic applications of related N–silylated analido group-4-metal compounds towards olefin polymerization, see: Gibson et al. (1998); Hill & Hitchcock (2002); Yuan et al. (2010). For related organometallic compounds with analogous analido ligands, see: Schumann et al. (2000); Chen (2008, 2009).
Experimental
Crystal data
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Refinement
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Data collection: SMART (Bruker, 2000); cell SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.
Supporting information
https://doi.org/10.1107/S1600536810025092/rk2217sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810025092/rk2217Isup2.hkl
TiCl4(THF)2 (0.48 g, 1.45 mmol) was added into the solution of [LiN(SiMe2NMe2)(2,6-Me2C6H3)]2 (0.66 g, 1.45 mmol) in Et2O (30 ml) at 273 K. The reaction mixture was warmed to room temperature and kept stirring for 12 h. It was dried in vacuum to remove all volatiles and the residue was extracted with CH2Cl2 (30 ml). Concentration of the filtrate under reduced pressure and recrystallization in toluene gave the title compound as purple crystals (yield 0.50 g, 66%).
The methyl H atoms were constrained to an ideal geometry, with C—H distances of 0.97Å and Uiso(H) = 1.5Ueq(C), but each group was allowed to rotate freely about its C—C, C—N and C—Si bonds. The other H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms, with C—H distances in the range 0.94Å and Uiso(H) = 1.2Ueq(C).
Group 4 metal
supported with the N–silylated anilido ligands were active catalysts for olefin polymerization (Gibson et al., 1998; Hill & Hitchcock, 2002). In particular, titanium were found to be more efficient and applicable (Alesso et al., 2008; Oakes et al., 2004; Tabernero et al., 2009). Therefore, the monoionic N–silylated anilido ligand bearing a pendant amino group was employed for synthesizing titanium compound. Analogous compounds with different metals including Zn (Schumann et al., 2000), Zr (Chen, 2009) and Fe (Chen, 2008) have been synthesized. Moreover, a group of zirconium with the similar ligand were reported showing good performance in ethylene polymerization (Yuan et al., 2010). It implied that the title titanium compound would behave better in catalysis application.The title compound was prepared by the metathetical reaction of TiCl4(THF)2 with [LiN(SiMe2NMe2)(2,6-Me2C6H3)]2. It is interesting that the valence of Ti has changed from IV to III. Similar situation could be found in Ovchinnikov's work (Ovchinnikov et al., 1993) and other - Chomitz et al., 2008). The driving factors for reduction will be investigated in further research. The suitable single–crystal of the title compound was obtained by recrystallization in toluene. Its molecular structure is shown in Fig. 1. In the monomeric molecular structure of title compound, the metal center is coordinated by two N–silylated anilido ligands. Each ligand has an N—Si—N chelating moiety, which is presumed to be a "quasi" conjugated unit owing to d···π–interaction between Si and N atoms. Two ligands are arranged in trans– to each other and obey the pseudo–C2 symmetrical operation. Such arrangement makes Ti atom right in the triangular planes of N1···N3···Cl1 and N2···N4···Cl1. The five–coordinate Ti(III) center demonstrates a highly distorted trigonal–bipyramid geometry (N2– and N4–apical atoms). The configuration is as same as the Fe(III) compound reported previously (Chen, 2008), presumably due to the same valence. The metal center Ti is chelated with an average N—Ti—N bite angle of 74.18 (13)°. The corresponding N—Si—N of the ligand is constrained to be about 95.25 (16)°. The mean Ti—Nanilido bond is 1.992 (3)Å, whereas the mean Ti—Namino bond is 2.286 (4)Å in the title compound. It suggests the former is much tighter than the latter. They are different from corresponding bond lengths 1.972 (4)Å and 2.356 (6)Å in a related amido Ti(III) compound reported by Chomitz et al. (2008).
For related titanium compounds, see: Ovchinnikov et al. (1993); Chomitz et al. (2008). For amido titanium compounds as olefin polymerization catalyts, see: Alesso et al. (2008); Oakes et al. (2004); Tabernero et al. (2009). For catalytic applications of related N–silylated analido group 4 metal compounds towards olefin polymerization, see: Gibson et al. (1998); Hill & Hitchcock (2002); Yuan et al. (2010). For related organometallic compounds with analogous analido ligands, see: Schumann et al. (2000); Chen (2008, 2009).
Data collection: SMART (Bruker, 2000); cell
SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).Fig. 1. The molecular structure, showing the atom–numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are presented as a small spheres of arbitrary radius. |
[Ti(C12H21N2Si)2Cl] | F(000) = 2248 |
Mr = 526.12 | Dx = 1.258 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 4223 reflections |
a = 34.145 (5) Å | θ = 2.3–27.6° |
b = 9.2718 (15) Å | µ = 0.51 mm−1 |
c = 20.909 (3) Å | T = 213 K |
β = 122.894 (2)° | Block, purple |
V = 5558.2 (15) Å3 | 0.40 × 0.30 × 0.15 mm |
Z = 8 |
Bruker SMART area-detector diffractometer | 4866 independent reflections |
Radiation source: fine–focus sealed tube | 4473 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.033 |
φ and ω scans | θmax = 25.0°, θmin = 1.4° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −40→40 |
Tmin = 0.814, Tmax = 0.928 | k = −6→11 |
10981 measured reflections | l = −24→24 |
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)] = 0.072 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.168 | H-atom parameters constrained |
S = 1.17 | w = 1/[σ2(Fo2) + (0.062P)2 + 21.4919P] where P = (Fo2 + 2Fc2)/3 |
4866 reflections | (Δ/σ)max = 0.001 |
289 parameters | Δρmax = 0.47 e Å−3 |
0 restraints | Δρmin = −0.48 e Å−3 |
[Ti(C12H21N2Si)2Cl] | V = 5558.2 (15) Å3 |
Mr = 526.12 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 34.145 (5) Å | µ = 0.51 mm−1 |
b = 9.2718 (15) Å | T = 213 K |
c = 20.909 (3) Å | 0.40 × 0.30 × 0.15 mm |
β = 122.894 (2)° |
Bruker SMART area-detector diffractometer | 4866 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 4473 reflections with I > 2σ(I) |
Tmin = 0.814, Tmax = 0.928 | Rint = 0.033 |
10981 measured reflections |
R[F2 > 2σ(F2)] = 0.072 | 0 restraints |
wR(F2) = 0.168 | H-atom parameters constrained |
S = 1.17 | w = 1/[σ2(Fo2) + (0.062P)2 + 21.4919P] where P = (Fo2 + 2Fc2)/3 |
4866 reflections | Δρmax = 0.47 e Å−3 |
289 parameters | Δρmin = −0.48 e Å−3 |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. |
Refinement. 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 | ||
Ti1 | 0.15222 (2) | 0.34275 (8) | 0.06414 (4) | 0.0231 (2) | |
Si1 | 0.14374 (4) | 0.45890 (13) | 0.18120 (7) | 0.0284 (3) | |
Si2 | 0.12637 (4) | 0.23530 (14) | −0.08132 (7) | 0.0291 (3) | |
Cl1 | 0.23284 (4) | 0.30582 (13) | 0.13779 (7) | 0.0399 (3) | |
N1 | 0.12378 (11) | 0.3088 (4) | 0.12435 (18) | 0.0249 (7) | |
N2 | 0.15461 (11) | 0.5585 (4) | 0.11873 (19) | 0.0278 (8) | |
N3 | 0.12846 (11) | 0.4008 (4) | −0.04285 (18) | 0.0266 (8) | |
N4 | 0.13576 (12) | 0.1310 (4) | −0.0022 (2) | 0.0302 (8) | |
C1 | 0.09894 (14) | 0.1945 (4) | 0.1318 (2) | 0.0255 (9) | |
C2 | 0.12258 (15) | 0.0776 (5) | 0.1805 (2) | 0.0310 (10) | |
C3 | 0.0969 (2) | −0.0339 (5) | 0.1844 (3) | 0.0461 (13) | |
H3A | 0.1126 | −0.1127 | 0.2166 | 0.055* | |
C4 | 0.0490 (2) | −0.0317 (6) | 0.1420 (3) | 0.0547 (15) | |
H4A | 0.0321 | −0.1075 | 0.1460 | 0.066* | |
C5 | 0.02597 (18) | 0.0816 (6) | 0.0941 (3) | 0.0492 (14) | |
H5A | −0.0068 | 0.0823 | 0.0649 | 0.059* | |
C6 | 0.04990 (15) | 0.1948 (5) | 0.0877 (3) | 0.0347 (10) | |
C7 | 0.17487 (16) | 0.0709 (5) | 0.2274 (3) | 0.0430 (12) | |
H7A | 0.1849 | −0.0171 | 0.2572 | 0.064* | |
H7B | 0.1871 | 0.1536 | 0.2612 | 0.064* | |
H7C | 0.1864 | 0.0719 | 0.1940 | 0.064* | |
C8 | 0.02325 (15) | 0.3130 (6) | 0.0313 (3) | 0.0456 (13) | |
H8A | −0.0099 | 0.2956 | 0.0064 | 0.068* | |
H8B | 0.0314 | 0.3148 | −0.0065 | 0.068* | |
H8C | 0.0311 | 0.4050 | 0.0576 | 0.068* | |
C9 | 0.10009 (19) | 0.5429 (6) | 0.1969 (3) | 0.0472 (13) | |
H9A | 0.1148 | 0.5659 | 0.2504 | 0.071* | |
H9B | 0.0746 | 0.4760 | 0.1814 | 0.071* | |
H9C | 0.0882 | 0.6305 | 0.1669 | 0.071* | |
C10 | 0.19967 (18) | 0.4424 (6) | 0.2747 (3) | 0.0453 (12) | |
H10A | 0.1962 | 0.4827 | 0.3142 | 0.068* | |
H10B | 0.2238 | 0.4945 | 0.2734 | 0.068* | |
H10C | 0.2082 | 0.3415 | 0.2856 | 0.068* | |
C11 | 0.11430 (17) | 0.6473 (5) | 0.0631 (3) | 0.0384 (11) | |
H11A | 0.1152 | 0.7391 | 0.0861 | 0.058* | |
H11B | 0.0856 | 0.5973 | 0.0481 | 0.058* | |
H11C | 0.1157 | 0.6639 | 0.0186 | 0.058* | |
C12 | 0.19724 (17) | 0.6475 (5) | 0.1534 (3) | 0.0409 (11) | |
H12A | 0.1927 | 0.7351 | 0.1740 | 0.061* | |
H12B | 0.2038 | 0.6722 | 0.1150 | 0.061* | |
H12C | 0.2233 | 0.5937 | 0.1941 | 0.061* | |
C13 | 0.12235 (15) | 0.5317 (5) | −0.0824 (2) | 0.0293 (10) | |
C14 | 0.07746 (16) | 0.5910 (5) | −0.1291 (2) | 0.0354 (11) | |
C15 | 0.0718 (2) | 0.7169 (6) | −0.1689 (3) | 0.0481 (13) | |
H15A | 0.0418 | 0.7561 | −0.2004 | 0.058* | |
C16 | 0.1094 (2) | 0.7862 (6) | −0.1633 (3) | 0.0550 (15) | |
H16A | 0.1050 | 0.8702 | −0.1916 | 0.066* | |
C17 | 0.1533 (2) | 0.7303 (5) | −0.1156 (3) | 0.0440 (12) | |
H17A | 0.1790 | 0.7789 | −0.1104 | 0.053* | |
C18 | 0.16069 (17) | 0.6047 (5) | −0.0751 (3) | 0.0357 (11) | |
C19 | 0.03519 (16) | 0.5235 (6) | −0.1355 (3) | 0.0473 (13) | |
H19A | 0.0077 | 0.5798 | −0.1702 | 0.071* | |
H19B | 0.0395 | 0.5215 | −0.0857 | 0.071* | |
H19C | 0.0313 | 0.4258 | −0.1547 | 0.071* | |
C20 | 0.20968 (17) | 0.5505 (6) | −0.0233 (3) | 0.0490 (13) | |
H20A | 0.2311 | 0.6145 | −0.0262 | 0.074* | |
H20B | 0.2122 | 0.4543 | −0.0388 | 0.074* | |
H20C | 0.2173 | 0.5478 | 0.0287 | 0.074* | |
C21 | 0.17307 (18) | 0.1982 (6) | −0.0987 (3) | 0.0476 (13) | |
H21A | 0.1593 | 0.1624 | −0.1502 | 0.071* | |
H21B | 0.1942 | 0.1264 | −0.0628 | 0.071* | |
H21C | 0.1901 | 0.2864 | −0.0924 | 0.071* | |
C22 | 0.06979 (18) | 0.1932 (6) | −0.1711 (3) | 0.0499 (13) | |
H22A | 0.0756 | 0.1580 | −0.2089 | 0.075* | |
H22B | 0.0509 | 0.2799 | −0.1900 | 0.075* | |
H22C | 0.0535 | 0.1200 | −0.1612 | 0.075* | |
C23 | 0.17362 (19) | 0.0209 (6) | 0.0299 (3) | 0.0484 (13) | |
H23A | 0.1629 | −0.0638 | −0.0026 | 0.073* | |
H23B | 0.1819 | −0.0059 | 0.0806 | 0.073* | |
H23C | 0.2007 | 0.0606 | 0.0325 | 0.073* | |
C24 | 0.09293 (18) | 0.0616 (6) | −0.0162 (3) | 0.0447 (13) | |
H24A | 0.0875 | −0.0273 | −0.0443 | 0.067* | |
H24B | 0.0667 | 0.1260 | −0.0455 | 0.067* | |
H24C | 0.0965 | 0.0403 | 0.0321 | 0.067* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ti1 | 0.0230 (4) | 0.0245 (4) | 0.0225 (4) | −0.0011 (3) | 0.0128 (3) | 0.0006 (3) |
Si1 | 0.0335 (6) | 0.0254 (6) | 0.0285 (6) | −0.0036 (5) | 0.0184 (5) | −0.0021 (5) |
Si2 | 0.0284 (6) | 0.0325 (7) | 0.0267 (6) | −0.0002 (5) | 0.0153 (5) | −0.0005 (5) |
Cl1 | 0.0239 (5) | 0.0453 (7) | 0.0430 (7) | 0.0024 (5) | 0.0133 (5) | 0.0003 (5) |
N1 | 0.0232 (17) | 0.0258 (19) | 0.0262 (17) | −0.0005 (14) | 0.0138 (15) | 0.0010 (15) |
N2 | 0.0294 (18) | 0.0220 (19) | 0.0297 (18) | −0.0025 (15) | 0.0146 (16) | −0.0010 (15) |
N3 | 0.0267 (18) | 0.0282 (19) | 0.0234 (17) | −0.0012 (15) | 0.0126 (15) | 0.0037 (15) |
N4 | 0.035 (2) | 0.0255 (19) | 0.0329 (19) | −0.0025 (16) | 0.0204 (17) | −0.0018 (16) |
C1 | 0.033 (2) | 0.024 (2) | 0.026 (2) | −0.0014 (18) | 0.0208 (19) | −0.0013 (18) |
C2 | 0.042 (3) | 0.025 (2) | 0.028 (2) | −0.0020 (19) | 0.021 (2) | −0.0024 (19) |
C3 | 0.069 (4) | 0.030 (3) | 0.038 (3) | −0.007 (2) | 0.028 (3) | 0.001 (2) |
C4 | 0.072 (4) | 0.044 (3) | 0.056 (3) | −0.030 (3) | 0.039 (3) | −0.002 (3) |
C5 | 0.039 (3) | 0.061 (4) | 0.047 (3) | −0.024 (3) | 0.023 (2) | −0.005 (3) |
C6 | 0.034 (2) | 0.038 (3) | 0.036 (2) | −0.005 (2) | 0.022 (2) | −0.004 (2) |
C7 | 0.048 (3) | 0.034 (3) | 0.040 (3) | 0.012 (2) | 0.019 (2) | 0.011 (2) |
C8 | 0.023 (2) | 0.052 (3) | 0.052 (3) | 0.003 (2) | 0.014 (2) | 0.003 (3) |
C9 | 0.065 (3) | 0.037 (3) | 0.060 (3) | −0.003 (3) | 0.047 (3) | −0.011 (3) |
C10 | 0.055 (3) | 0.039 (3) | 0.031 (2) | −0.012 (2) | 0.017 (2) | −0.004 (2) |
C11 | 0.046 (3) | 0.030 (3) | 0.038 (3) | 0.005 (2) | 0.023 (2) | 0.006 (2) |
C12 | 0.042 (3) | 0.033 (3) | 0.046 (3) | −0.012 (2) | 0.022 (2) | −0.007 (2) |
C13 | 0.039 (2) | 0.029 (2) | 0.020 (2) | 0.0034 (19) | 0.0163 (19) | 0.0016 (18) |
C14 | 0.046 (3) | 0.035 (3) | 0.026 (2) | 0.007 (2) | 0.020 (2) | 0.002 (2) |
C15 | 0.060 (3) | 0.044 (3) | 0.034 (3) | 0.021 (3) | 0.022 (3) | 0.012 (2) |
C16 | 0.097 (5) | 0.031 (3) | 0.054 (3) | 0.008 (3) | 0.052 (4) | 0.011 (3) |
C17 | 0.068 (4) | 0.029 (3) | 0.051 (3) | −0.003 (2) | 0.043 (3) | −0.002 (2) |
C18 | 0.048 (3) | 0.032 (3) | 0.035 (2) | −0.005 (2) | 0.028 (2) | −0.005 (2) |
C19 | 0.039 (3) | 0.055 (3) | 0.042 (3) | 0.016 (2) | 0.018 (2) | 0.008 (3) |
C20 | 0.043 (3) | 0.050 (3) | 0.057 (3) | −0.018 (2) | 0.029 (3) | −0.003 (3) |
C21 | 0.054 (3) | 0.049 (3) | 0.054 (3) | −0.001 (3) | 0.039 (3) | −0.003 (3) |
C22 | 0.046 (3) | 0.053 (3) | 0.039 (3) | −0.002 (3) | 0.015 (2) | −0.010 (3) |
C23 | 0.062 (3) | 0.036 (3) | 0.044 (3) | 0.017 (2) | 0.026 (3) | 0.007 (2) |
C24 | 0.060 (3) | 0.042 (3) | 0.047 (3) | −0.023 (3) | 0.039 (3) | −0.015 (2) |
Ti1—N1 | 1.989 (3) | C10—H10A | 0.9700 |
Ti1—N3 | 1.995 (3) | C10—H10B | 0.9700 |
Ti1—N2 | 2.282 (4) | C10—H10C | 0.9700 |
Ti1—N4 | 2.291 (4) | C11—H11A | 0.9700 |
Ti1—Cl1 | 2.3374 (13) | C11—H11B | 0.9700 |
Si1—N1 | 1.713 (4) | C11—H11C | 0.9700 |
Si1—N2 | 1.795 (4) | C12—H12A | 0.9700 |
Si1—C10 | 1.855 (5) | C12—H12B | 0.9700 |
Si1—C9 | 1.861 (5) | C12—H12C | 0.9700 |
Si2—N3 | 1.716 (4) | C13—C18 | 1.406 (6) |
Si2—N4 | 1.789 (4) | C13—C14 | 1.407 (6) |
Si2—C21 | 1.851 (5) | C14—C15 | 1.386 (7) |
Si2—C22 | 1.863 (5) | C14—C19 | 1.511 (7) |
N1—C1 | 1.418 (5) | C15—C16 | 1.383 (8) |
N2—C12 | 1.476 (5) | C15—H15A | 0.9400 |
N2—C11 | 1.479 (6) | C16—C17 | 1.374 (8) |
N3—C13 | 1.419 (5) | C16—H16A | 0.9400 |
N4—C24 | 1.474 (6) | C17—C18 | 1.380 (7) |
N4—C23 | 1.490 (6) | C17—H17A | 0.9400 |
C1—C2 | 1.403 (6) | C18—C20 | 1.502 (7) |
C1—C6 | 1.406 (6) | C19—H19A | 0.9700 |
C2—C3 | 1.387 (6) | C19—H19B | 0.9700 |
C2—C7 | 1.500 (6) | C19—H19C | 0.9700 |
C3—C4 | 1.374 (8) | C20—H20A | 0.9700 |
C3—H3A | 0.9400 | C20—H20B | 0.9700 |
C4—C5 | 1.367 (8) | C20—H20C | 0.9700 |
C4—H4A | 0.9400 | C21—H21A | 0.9700 |
C5—C6 | 1.381 (6) | C21—H21B | 0.9700 |
C5—H5A | 0.9400 | C21—H21C | 0.9700 |
C6—C8 | 1.501 (7) | C22—H22A | 0.9700 |
C7—H7A | 0.9700 | C22—H22B | 0.9700 |
C7—H7B | 0.9700 | C22—H22C | 0.9700 |
C7—H7C | 0.9700 | C23—H23A | 0.9700 |
C8—H8A | 0.9700 | C23—H23B | 0.9700 |
C8—H8B | 0.9700 | C23—H23C | 0.9700 |
C8—H8C | 0.9700 | C24—H24A | 0.9700 |
C9—H9A | 0.9700 | C24—H24B | 0.9700 |
C9—H9B | 0.9700 | C24—H24C | 0.9700 |
C9—H9C | 0.9700 | ||
N1—Ti1—N3 | 135.36 (14) | H8B—C8—H8C | 109.5 |
N1—Ti1—N2 | 73.69 (13) | Si1—C9—H9A | 109.5 |
N3—Ti1—N2 | 101.94 (14) | Si1—C9—H9B | 109.5 |
N1—Ti1—N4 | 101.77 (13) | H9A—C9—H9B | 109.5 |
N3—Ti1—N4 | 74.68 (14) | Si1—C9—H9C | 109.5 |
N2—Ti1—N4 | 169.84 (13) | H9A—C9—H9C | 109.5 |
N1—Ti1—Cl1 | 111.41 (10) | H9B—C9—H9C | 109.5 |
N3—Ti1—Cl1 | 113.23 (10) | Si1—C10—H10A | 109.5 |
N2—Ti1—Cl1 | 95.13 (9) | Si1—C10—H10B | 109.5 |
N4—Ti1—Cl1 | 95.00 (10) | H10A—C10—H10B | 109.5 |
N3—Ti1—Si1 | 134.19 (11) | Si1—C10—H10C | 109.5 |
N4—Ti1—Si1 | 138.01 (9) | H10A—C10—H10C | 109.5 |
Cl1—Ti1—Si1 | 97.07 (5) | H10B—C10—H10C | 109.5 |
N1—Ti1—Si2 | 130.26 (10) | N2—C11—H11A | 109.5 |
N2—Ti1—Si2 | 138.34 (9) | N2—C11—H11B | 109.5 |
Cl1—Ti1—Si2 | 102.91 (4) | H11A—C11—H11B | 109.5 |
Si1—Ti1—Si2 | 159.95 (4) | N2—C11—H11C | 109.5 |
N1—Si1—N2 | 94.26 (16) | H11A—C11—H11C | 109.5 |
N1—Si1—C10 | 117.3 (2) | H11B—C11—H11C | 109.5 |
N2—Si1—C10 | 108.0 (2) | N2—C12—H12A | 109.5 |
N1—Si1—C9 | 114.0 (2) | N2—C12—H12B | 109.5 |
N2—Si1—C9 | 114.5 (2) | H12A—C12—H12B | 109.5 |
C10—Si1—C9 | 108.3 (2) | N2—C12—H12C | 109.5 |
C10—Si1—Ti1 | 110.52 (18) | H12A—C12—H12C | 109.5 |
C9—Si1—Ti1 | 141.20 (18) | H12B—C12—H12C | 109.5 |
N3—Si2—N4 | 96.25 (16) | C18—C13—C14 | 119.1 (4) |
N3—Si2—C21 | 116.0 (2) | C18—C13—N3 | 121.0 (4) |
N4—Si2—C21 | 109.9 (2) | C14—C13—N3 | 119.9 (4) |
N3—Si2—C22 | 114.6 (2) | C15—C14—C13 | 119.4 (5) |
N4—Si2—C22 | 112.7 (2) | C15—C14—C19 | 118.8 (4) |
C21—Si2—C22 | 107.2 (2) | C13—C14—C19 | 121.9 (4) |
C21—Si2—Ti1 | 118.36 (18) | C16—C15—C14 | 121.3 (5) |
C22—Si2—Ti1 | 134.44 (18) | C16—C15—H15A | 119.3 |
C1—N1—Si1 | 124.5 (3) | C14—C15—H15A | 119.3 |
C1—N1—Ti1 | 135.6 (3) | C17—C16—C15 | 118.9 (5) |
Si1—N1—Ti1 | 99.43 (16) | C17—C16—H16A | 120.6 |
C12—N2—C11 | 108.9 (4) | C15—C16—H16A | 120.6 |
C12—N2—Si1 | 117.9 (3) | C16—C17—C18 | 121.9 (5) |
C11—N2—Si1 | 112.8 (3) | C16—C17—H17A | 119.1 |
C12—N2—Ti1 | 119.6 (3) | C18—C17—H17A | 119.1 |
C11—N2—Ti1 | 109.2 (3) | C17—C18—C13 | 119.4 (5) |
Si1—N2—Ti1 | 87.02 (14) | C17—C18—C20 | 119.1 (4) |
C13—N3—Si2 | 122.5 (3) | C13—C18—C20 | 121.6 (4) |
C13—N3—Ti1 | 136.5 (3) | C14—C19—H19A | 109.5 |
Si2—N3—Ti1 | 99.94 (17) | C14—C19—H19B | 109.5 |
C24—N4—C23 | 108.3 (4) | H19A—C19—H19B | 109.5 |
C24—N4—Si2 | 113.1 (3) | C14—C19—H19C | 109.5 |
C23—N4—Si2 | 117.5 (3) | H19A—C19—H19C | 109.5 |
C24—N4—Ti1 | 112.7 (3) | H19B—C19—H19C | 109.5 |
C23—N4—Ti1 | 116.6 (3) | C18—C20—H20A | 109.5 |
Si2—N4—Ti1 | 87.61 (15) | C18—C20—H20B | 109.5 |
C2—C1—C6 | 119.2 (4) | H20A—C20—H20B | 109.5 |
C2—C1—N1 | 121.0 (4) | C18—C20—H20C | 109.5 |
C6—C1—N1 | 119.8 (4) | H20A—C20—H20C | 109.5 |
C3—C2—C1 | 119.0 (4) | H20B—C20—H20C | 109.5 |
C3—C2—C7 | 119.8 (4) | Si2—C21—H21A | 109.5 |
C1—C2—C7 | 121.2 (4) | Si2—C21—H21B | 109.5 |
C4—C3—C2 | 121.4 (5) | H21A—C21—H21B | 109.5 |
C4—C3—H3A | 119.3 | Si2—C21—H21C | 109.5 |
C2—C3—H3A | 119.3 | H21A—C21—H21C | 109.5 |
C5—C4—C3 | 119.5 (5) | H21B—C21—H21C | 109.5 |
C5—C4—H4A | 120.2 | Si2—C22—H22A | 109.5 |
C3—C4—H4A | 120.2 | Si2—C22—H22B | 109.5 |
C4—C5—C6 | 121.4 (5) | H22A—C22—H22B | 109.5 |
C4—C5—H5A | 119.3 | Si2—C22—H22C | 109.5 |
C6—C5—H5A | 119.3 | H22A—C22—H22C | 109.5 |
C5—C6—C1 | 119.4 (5) | H22B—C22—H22C | 109.5 |
C5—C6—C8 | 119.5 (4) | N4—C23—H23A | 109.5 |
C1—C6—C8 | 121.0 (4) | N4—C23—H23B | 109.5 |
C2—C7—H7A | 109.5 | H23A—C23—H23B | 109.5 |
C2—C7—H7B | 109.5 | N4—C23—H23C | 109.5 |
H7A—C7—H7B | 109.5 | H23A—C23—H23C | 109.5 |
C2—C7—H7C | 109.5 | H23B—C23—H23C | 109.5 |
H7A—C7—H7C | 109.5 | N4—C24—H24A | 109.5 |
H7B—C7—H7C | 109.5 | N4—C24—H24B | 109.5 |
C6—C8—H8A | 109.5 | H24A—C24—H24B | 109.5 |
C6—C8—H8B | 109.5 | N4—C24—H24C | 109.5 |
H8A—C8—H8B | 109.5 | H24A—C24—H24C | 109.5 |
C6—C8—H8C | 109.5 | H24B—C24—H24C | 109.5 |
H8A—C8—H8C | 109.5 |
Experimental details
Crystal data | |
Chemical formula | [Ti(C12H21N2Si)2Cl] |
Mr | 526.12 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 213 |
a, b, c (Å) | 34.145 (5), 9.2718 (15), 20.909 (3) |
β (°) | 122.894 (2) |
V (Å3) | 5558.2 (15) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.51 |
Crystal size (mm) | 0.40 × 0.30 × 0.15 |
Data collection | |
Diffractometer | Bruker SMART area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.814, 0.928 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 10981, 4866, 4473 |
Rint | 0.033 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.072, 0.168, 1.17 |
No. of reflections | 4866 |
No. of parameters | 289 |
H-atom treatment | H-atom parameters constrained |
w = 1/[σ2(Fo2) + (0.062P)2 + 21.4919P] where P = (Fo2 + 2Fc2)/3 | |
Δρmax, Δρmin (e Å−3) | 0.47, −0.48 |
Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
Ti1—N1 | 1.989 (3) | Ti1—N4 | 2.291 (4) |
Ti1—N3 | 1.995 (3) | Ti1—Cl1 | 2.3374 (13) |
Ti1—N2 | 2.282 (4) |
Acknowledgements
This work was carried out under the sponsorship of the Natural Science Foundation of Shanxi Province (2008011024).
References
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Group 4 metal amides supported with the N–silylated anilido ligands were active catalysts for olefin polymerization (Gibson et al., 1998; Hill & Hitchcock, 2002). In particular, titanium amides were found to be more efficient and applicable (Alesso et al., 2008; Oakes et al., 2004; Tabernero et al., 2009). Therefore, the monoionic N–silylated anilido ligand bearing a pendant amino group was employed for synthesizing titanium compound. Analogous compounds with different metals including Zn (Schumann et al., 2000), Zr (Chen, 2009) and Fe (Chen, 2008) have been synthesized. Moreover, a group of zirconium amides with the similar ligand were reported showing good performance in ethylene polymerization (Yuan et al., 2010). It implied that the title titanium compound would behave better in catalysis application.
The title compound was prepared by the metathetical reaction of TiCl4(THF)2 with [LiN(SiMe2NMe2)(2,6-Me2C6H3)]2. It is interesting that the valence of Ti has changed from IV to III. Similar situation could be found in Ovchinnikov's work (Ovchinnikov et al., 1993) and other - Chomitz et al., 2008). The driving factors for reduction will be investigated in further research. The suitable single–crystal of the title compound was obtained by recrystallization in toluene. Its molecular structure is shown in Fig. 1. In the monomeric molecular structure of title compound, the metal center is coordinated by two N–silylated anilido ligands. Each ligand has an N—Si—N chelating moiety, which is presumed to be a "quasi" conjugated unit owing to d···π–interaction between Si and N atoms. Two ligands are arranged in trans– to each other and obey the pseudo–C2 symmetrical operation. Such arrangement makes Ti atom right in the triangular planes of N1···N3···Cl1 and N2···N4···Cl1. The five–coordinate Ti(III) center demonstrates a highly distorted trigonal–bipyramid geometry (N2– and N4–apical atoms). The configuration is as same as the Fe(III) compound reported previously (Chen, 2008), presumably due to the same valence. The metal center Ti is chelated with an average N—Ti—N bite angle of 74.18 (13)°. The corresponding N—Si—N of the ligand is constrained to be about 95.25 (16)°. The mean Ti—Nanilido bond is 1.992 (3)Å, whereas the mean Ti—Namino bond is 2.286 (4)Å in the title compound. It suggests the former is much tighter than the latter. They are different from corresponding bond lengths 1.972 (4)Å and 2.356 (6)Å in a related amido Ti(III) compound reported by Chomitz et al. (2008).