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In the mol­ecule of the title compound, [TiBr2(C13H14)], the TiIV centre is in a distorted tetra­hedral environment involving two η5-bonded cyclo­penta­dienyl rings of a propane-2,2-diyldicyclo­penta­dienyl ligand [Ti—Cg = 2.045 (2) Å; Cg is the centroid of the cyclo­penta­dienyl ring] and two Br atoms [Ti—Br = 2.5115 (7) Å]. The presence of the short 2,2-propyl­idene bridge between the two cyclo­penta­dienyl rings constrains the Cg—Ti—Cg angle to a value of 121.32 (9)°. The Ti and central C atoms are located on a crystallographic C2 axis.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807048921/hk2334sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536807048921/hk2334Isup2.hkl
Contains datablock I

CCDC reference: 667140

Key indicators

  • Single-crystal X-ray study
  • T = 150 K
  • Mean [sigma](C-C) = 0.006 Å
  • R factor = 0.052
  • wR factor = 0.147
  • Data-to-parameter ratio = 19.4

checkCIF/PLATON results

No syntax errors found



Alert level C DIFMX01_ALERT_2_C The maximum difference density is > 0.1*ZMAX*0.75 _refine_diff_density_max given = 3.382 Test value = 2.625 DIFMX02_ALERT_1_C The maximum difference density is > 0.1*ZMAX*0.75 The relevant atom site should be identified. PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density .... 2.26 PLAT097_ALERT_2_C Maximum (Positive) Residual Density ............ 3.38 e/A    PLAT180_ALERT_3_C Check Cell Rounding: # of Values Ending with 0 = 3 PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) . 1.11 Ratio
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 6 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 3 ALERT type 2 Indicator that the structure model may be wrong or deficient 1 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check

Comment top

Group 4 cyclopentadienyl complexes belong to important class of catalysts for methylalumoxane-promoted polymerization of olefines. In order to find a relationship between the structure and catalytic activity, large series of variously substituted derivatives have been synthesized. It was found that incorporation of short interannular bridge connecting both cyclopentadienyl rings leads to disclosuring of electronically unsaturated central metal atom that is better accessible to be attacked by electron-rich olefin. We prepared the title complex, (I), in the framework of our investigation of catalytically active cyclopentadienyl complexes and we report herein its crystal structure.

In the molecule of the title compound, (I), Ti1 and C6 atoms are located on a crystallographic C2 axis (Fig. 1). It is a typical ansa-metallocene structure with two cyclopentadienyl rings interconnected together with propylidene bridge. The TiIV centre is in a distorted tetrahedral environment involving two η5-bonded cyclopentadienyl rings of (C13H14)2- ligand and two Br atoms (Table 1).

In (I), the angle between the planes of cyclopentadienyl rings is 65.8 (3)°, in which it reflects the degree of the disclosure of the central C6 atom. In the analogous dichloride {TiCl2[(C5H4)2C(CH3)2]}, (II), (Koch et al., 2000) and difluoride {TiF2[(C5H4)2C(CH3)2]}, (III), (Picka et al., 2005) complexes, the observed angles are 66.8 (10)° in (II) and 65.76 (9)° in (III).

The Ti1—Cg [2.045 (2) Å; Cg is the centroid of cyclopentadienyl ring] distance in (I) is shorter than the reported value [Ti—Cg = 2.193 Å] in (II), but it is nearly the same with the corresponding values [Ti1—Cg1 = 2.0558 (7) Å and Ti1—Cg2 = 2.0567 (8) Å] in (III). In (I), the Ti1—Br1 distance is 2.5115 (7) Å. The constraining of the Cg—Ti—Cg angle to a value of 121.32 (9)° is caused by the presence of the short 2,2-propylidene bridge between the two cyclopenta- dienyl rings.

On the inspection of ascertained geometric parameters, it is evident that the substitution of halide ligands in ansa-complexes of this type has no significant impact on the structure of [Ti(C13H14)]2+ unit.

Related literature top

For related structures, see: Koch et al. (2000); Picka et al. (2005).

Experimental top

Compound (I) was prepared from the chloride derivative (II) by the reaction with boron tribromide in dichloromethane. Starting complex (II) (0.22 g, 0.69 mmol) was dissolved in dry dichloromethane (20 ml) and boron tribromide (0.47 mmol, 0.045 ml) was added. The green-coloured reaction mixture was stirred for 2 h at room temperature and volatiles were evaporated in vacuo. The solid residue was washed three times with hexane (10 ml) and dried in vacuo (yield; 0.2 g, 75%). Upon slow evaporation of saturated chloroform solution at 270 K, green crystals of (I) suitable for X-ray analysis were obtained.

Refinement top

The highest peak in the final difference electron-density map is located 1.05 Å from the Br1 atom. H atoms were positioned geometrically, with C—H = 0.93 and 0.97 Å, for aromatic and methyl H atoms and constrained to ride on their parent atoms, with Uiso(H) = xUeq(C), where x = 1.2 for aromatic H and x = 1.5 for methyl H atoms.

Structure description top

Group 4 cyclopentadienyl complexes belong to important class of catalysts for methylalumoxane-promoted polymerization of olefines. In order to find a relationship between the structure and catalytic activity, large series of variously substituted derivatives have been synthesized. It was found that incorporation of short interannular bridge connecting both cyclopentadienyl rings leads to disclosuring of electronically unsaturated central metal atom that is better accessible to be attacked by electron-rich olefin. We prepared the title complex, (I), in the framework of our investigation of catalytically active cyclopentadienyl complexes and we report herein its crystal structure.

In the molecule of the title compound, (I), Ti1 and C6 atoms are located on a crystallographic C2 axis (Fig. 1). It is a typical ansa-metallocene structure with two cyclopentadienyl rings interconnected together with propylidene bridge. The TiIV centre is in a distorted tetrahedral environment involving two η5-bonded cyclopentadienyl rings of (C13H14)2- ligand and two Br atoms (Table 1).

In (I), the angle between the planes of cyclopentadienyl rings is 65.8 (3)°, in which it reflects the degree of the disclosure of the central C6 atom. In the analogous dichloride {TiCl2[(C5H4)2C(CH3)2]}, (II), (Koch et al., 2000) and difluoride {TiF2[(C5H4)2C(CH3)2]}, (III), (Picka et al., 2005) complexes, the observed angles are 66.8 (10)° in (II) and 65.76 (9)° in (III).

The Ti1—Cg [2.045 (2) Å; Cg is the centroid of cyclopentadienyl ring] distance in (I) is shorter than the reported value [Ti—Cg = 2.193 Å] in (II), but it is nearly the same with the corresponding values [Ti1—Cg1 = 2.0558 (7) Å and Ti1—Cg2 = 2.0567 (8) Å] in (III). In (I), the Ti1—Br1 distance is 2.5115 (7) Å. The constraining of the Cg—Ti—Cg angle to a value of 121.32 (9)° is caused by the presence of the short 2,2-propylidene bridge between the two cyclopenta- dienyl rings.

On the inspection of ascertained geometric parameters, it is evident that the substitution of halide ligands in ansa-complexes of this type has no significant impact on the structure of [Ti(C13H14)]2+ unit.

For related structures, see: Koch et al. (2000); Picka et al. (2005).

Computing details top

Data collection: COLLECT (Hooft, 1998) and DENZO (Otwinowski & Minor, 1997); cell refinement: COLLECT (Hooft, 1998) and DENZO (Otwinowski & Minor, 1997); data reduction: COLLECT (Hooft, 1998) and DENZO (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: enCIFer (Allen et al., 2004).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level [symmetry code (a): 2 - x, y, 3/2 - z].
Dibromido(η5,η5-propane-2,2-diyldicyclopentadienyl)titanium(IV) top
Crystal data top
[TiBr2(C13H14)]F(000) = 736
Mr = 377.96Dx = 1.954 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 5340 reflections
a = 13.1890 (4) Åθ = 1–27.5°
b = 9.7180 (3) ŵ = 6.85 mm1
c = 10.8200 (3) ÅT = 150 K
β = 112.0801 (18)°Prism, green
V = 1285.10 (7) Å30.22 × 0.15 × 0.08 mm
Z = 4
Data collection top
Nonius KappaCCD area-detector
diffractometer
1475 independent reflections
Radiation source: fine-focus sealed tube1333 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.079
Detector resolution: 9.091 pixels mm-1θmax = 27.5°, θmin = 2.7°
φ and ω scansh = 1717
Absorption correction: integration
(Gaussian; Coppens, 1970)
k = 1212
Tmin = 0.274, Tmax = 0.721l = 1414
10067 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.053H-atom parameters constrained
wR(F2) = 0.147 w = 1/[σ2(Fo2) + (0.0967P)2 + 2.0144P]
where P = (Fo2 + 2Fc2)/3
S = 1.17(Δ/σ)max < 0.001
1475 reflectionsΔρmax = 3.38 e Å3
76 parametersΔρmin = 1.50 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0032 (9)
Crystal data top
[TiBr2(C13H14)]V = 1285.10 (7) Å3
Mr = 377.96Z = 4
Monoclinic, C2/cMo Kα radiation
a = 13.1890 (4) ŵ = 6.85 mm1
b = 9.7180 (3) ÅT = 150 K
c = 10.8200 (3) Å0.22 × 0.15 × 0.08 mm
β = 112.0801 (18)°
Data collection top
Nonius KappaCCD area-detector
diffractometer
1475 independent reflections
Absorption correction: integration
(Gaussian; Coppens, 1970)
1333 reflections with I > 2σ(I)
Tmin = 0.274, Tmax = 0.721Rint = 0.079
10067 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0530 restraints
wR(F2) = 0.147H-atom parameters constrained
S = 1.17Δρmax = 3.38 e Å3
1475 reflectionsΔρmin = 1.50 e Å3
76 parameters
Special details top

Experimental. M.p.: 610 K (dec.) Spectroscopic analysis: 1H NMR (CDCl3, δ, p.p.m.): 6.98 (m, 4H), 5.72 (m, 4H), 1.83 (s, 6H). 13C NMR (CDCl3, δ, p.p.m.): 23.3, 36.8, 114.2, 115.5, 131.3. IR (KBr disc, cm-1): 3124 (m), 3101 (m), 3087 (m), 2980 (m), 2967 (m), 2855 (w), 1479 (w), 1465 (m), 1442 (w), 1416 (m), 1383 (m), 1374 (w), 1271 (s), 1225 (w), 1152 (m), 1074 (w), 1048 (m), 947 (w), 907 (m), 885 (w), 875 (m), 845 (w), 829 (s), 817 (s), 733 (s), 733 (s), 706 (m), 608 (w), 464 (m), 424 (m), 319 (m); Raman (quartz capillary, cm-1): 2123 (m), 3100 (m), 3086 (w), 2988 (w), 2941(w), 2918(w), 2870 (w), 1481 (w), 1465 (w), 1447 (w), 1408 (m), 1339 (w), 1348 (w), 1271 (m), 1225 (w), 1152 (m), 1082 (w), 1065 (w), 950 (w), 875 (m), 847 (w), 826 (w), 733 (w), 548 (w), 462 (m) 424 (m), 367 (m), 334 (w), 323 (w), 262 (s), 207 (w), 169 (s), 157 (m), 116 (s), 84 (s); UV-Vis (CH2Cl2, maxima at nm): 593, 406, 319(sh), 271; Elemental analysis, calculated for C13H14Br2Ti: C 41.31, H 3.73; found: C 41.12, H 3.75.

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. 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Ti11.00000.31726 (9)0.75000.0164 (3)
Br11.15259 (4)0.48873 (4)0.84124 (4)0.0255 (3)
C11.0122 (4)0.1080 (4)0.6515 (4)0.0208 (8)
C21.1089 (4)0.1829 (4)0.6708 (4)0.0229 (9)
H21.17870.16040.73050.027*
C31.0818 (4)0.2977 (5)0.5840 (5)0.0283 (10)
H31.13110.36150.57490.034*
C40.9700 (4)0.2992 (4)0.5152 (4)0.0276 (10)
H40.93080.36430.45250.033*
C50.9253 (4)0.1831 (4)0.5574 (4)0.0235 (9)
H50.85150.16040.52810.028*
C61.00000.0042 (5)0.75000.0210 (13)
C70.8971 (4)0.0858 (5)0.6889 (5)0.0302 (10)
H7A0.88590.13780.75810.045*
H7B0.90650.14760.62480.045*
H7C0.83470.02810.64560.045*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ti10.0165 (5)0.0176 (5)0.0146 (5)0.0000.0053 (4)0.000
Br10.0183 (4)0.0283 (3)0.0276 (4)0.00664 (14)0.0059 (3)0.00450 (15)
C10.028 (2)0.0198 (18)0.017 (2)0.0003 (16)0.0108 (17)0.0039 (15)
C20.026 (2)0.025 (2)0.024 (2)0.0030 (16)0.0167 (19)0.0037 (16)
C30.037 (3)0.028 (2)0.030 (2)0.0029 (19)0.025 (2)0.0050 (19)
C40.048 (3)0.021 (2)0.016 (2)0.0031 (19)0.014 (2)0.0008 (16)
C50.028 (2)0.025 (2)0.015 (2)0.0020 (16)0.0046 (18)0.0031 (16)
C60.021 (3)0.018 (3)0.021 (3)0.0000.005 (3)0.000
C70.040 (3)0.024 (2)0.027 (2)0.0103 (19)0.014 (2)0.0057 (18)
Geometric parameters (Å, º) top
Ti1—C1i2.329 (4)C1—C61.520 (5)
Ti1—C12.329 (4)C2—C31.415 (6)
Ti1—C2i2.330 (4)C2—H20.9300
Ti1—C22.330 (4)C3—C41.380 (7)
Ti1—C52.339 (4)C3—H30.9300
Ti1—C5i2.339 (4)C4—C51.425 (6)
Ti1—C32.425 (4)C4—H40.9300
Ti1—C3i2.425 (4)C5—H50.9300
Ti1—C42.426 (4)C6—C1i1.520 (5)
Ti1—C4i2.426 (4)C6—C71.539 (5)
Ti1—Br12.5116 (7)C6—C7i1.539 (5)
Ti1—Br1i2.5116 (7)C7—H7A0.9600
C1—C21.414 (6)C7—H7B0.9600
C1—C51.415 (6)C7—H7C0.9600
C1i—Ti1—C158.40 (18)C4i—Ti1—Br181.10 (12)
C1i—Ti1—C2i35.34 (15)C1i—Ti1—Br1i125.18 (11)
C1—Ti1—C2i80.63 (14)C1—Ti1—Br1i125.60 (11)
C1i—Ti1—C280.63 (14)C2i—Ti1—Br1i90.16 (11)
C1—Ti1—C235.34 (15)C2—Ti1—Br1i137.81 (11)
C2i—Ti1—C2111.8 (2)C5—Ti1—Br1i90.74 (11)
C1i—Ti1—C580.95 (15)C5i—Ti1—Br1i136.63 (11)
C1—Ti1—C535.29 (15)C3—Ti1—Br1i105.95 (12)
C2i—Ti1—C584.49 (16)C3i—Ti1—Br1i80.16 (12)
C2—Ti1—C558.06 (16)C4—Ti1—Br1i81.10 (12)
C1i—Ti1—C5i35.29 (15)C4i—Ti1—Br1i104.53 (12)
C1—Ti1—C5i80.95 (15)Br1—Ti1—Br1i96.87 (4)
C2i—Ti1—C5i58.06 (16)C2—C1—C5106.4 (4)
C2—Ti1—C5i84.49 (16)C2—C1—C6124.4 (4)
C5—Ti1—C5i112.2 (2)C5—C1—C6125.2 (3)
C1i—Ti1—C3113.39 (14)C2—C1—Ti172.4 (2)
C1—Ti1—C357.75 (14)C5—C1—Ti172.7 (2)
C2i—Ti1—C3137.38 (15)C6—C1—Ti1102.4 (2)
C2—Ti1—C334.55 (15)C1—C2—C3108.6 (4)
C5—Ti1—C356.78 (16)C1—C2—Ti172.3 (2)
C5i—Ti1—C3117.42 (16)C3—C2—Ti176.4 (2)
C1i—Ti1—C3i57.75 (14)C1—C2—H2125.7
C1—Ti1—C3i113.39 (14)C3—C2—H2125.7
C2i—Ti1—C3i34.55 (15)Ti1—C2—H2117.5
C2—Ti1—C3i137.38 (15)C4—C3—C2108.5 (4)
C5—Ti1—C3i117.42 (16)C4—C3—Ti173.5 (2)
C5i—Ti1—C3i56.78 (16)C2—C3—Ti169.0 (2)
C3—Ti1—C3i171.0 (2)C4—C3—H3125.7
C1i—Ti1—C4113.82 (14)C2—C3—H3125.7
C1—Ti1—C457.97 (14)Ti1—C3—H3123.3
C2i—Ti1—C4117.65 (16)C3—C4—C5107.8 (4)
C2—Ti1—C456.95 (16)C3—C4—Ti173.5 (2)
C5—Ti1—C434.74 (15)C5—C4—Ti169.3 (2)
C5i—Ti1—C4137.81 (15)C3—C4—H4126.1
C3—Ti1—C433.06 (18)C5—C4—H4126.1
C3i—Ti1—C4145.77 (18)Ti1—C4—H4122.8
C1i—Ti1—C4i57.97 (14)C1—C5—C4108.6 (4)
C1—Ti1—C4i113.82 (14)C1—C5—Ti172.0 (2)
C2i—Ti1—C4i56.95 (16)C4—C5—Ti176.0 (2)
C2—Ti1—C4i117.65 (16)C1—C5—H5125.7
C5—Ti1—C4i137.81 (15)C4—C5—H5125.7
C5i—Ti1—C4i34.74 (15)Ti1—C5—H5118.2
C3—Ti1—C4i145.77 (18)C1—C6—C1i96.8 (4)
C3i—Ti1—C4i33.06 (18)C1—C6—C7112.6 (2)
C4—Ti1—C4i171.7 (2)C1i—C6—C7111.7 (2)
C1i—Ti1—Br1125.60 (11)C1—C6—C7i111.7 (2)
C1—Ti1—Br1125.18 (11)C1i—C6—C7i112.6 (2)
C2i—Ti1—Br1137.81 (11)C7—C6—C7i110.8 (5)
C2—Ti1—Br190.16 (11)C6—C7—H7A109.5
C5—Ti1—Br1136.63 (11)C6—C7—H7B109.5
C5i—Ti1—Br190.74 (11)H7A—C7—H7B109.5
C3—Ti1—Br180.16 (12)C6—C7—H7C109.5
C3i—Ti1—Br1105.95 (12)H7A—C7—H7C109.5
C4—Ti1—Br1104.53 (12)H7B—C7—H7C109.5
Symmetry code: (i) x+2, y, z+3/2.

Experimental details

Crystal data
Chemical formula[TiBr2(C13H14)]
Mr377.96
Crystal system, space groupMonoclinic, C2/c
Temperature (K)150
a, b, c (Å)13.1890 (4), 9.7180 (3), 10.8200 (3)
β (°) 112.0801 (18)
V3)1285.10 (7)
Z4
Radiation typeMo Kα
µ (mm1)6.85
Crystal size (mm)0.22 × 0.15 × 0.08
Data collection
DiffractometerNonius KappaCCD area-detector
Absorption correctionIntegration
(Gaussian; Coppens, 1970)
Tmin, Tmax0.274, 0.721
No. of measured, independent and
observed [I > 2σ(I)] reflections
10067, 1475, 1333
Rint0.079
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.053, 0.147, 1.17
No. of reflections1475
No. of parameters76
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)3.38, 1.50

Computer programs: COLLECT (Hooft, 1998) and DENZO (Otwinowski & Minor, 1997), SIR92 (Altomare et al., 1994), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 2003), enCIFer (Allen et al., 2004).

Selected geometric parameters (Å, °). top
Ti—Cg12.045 (2)C1—C6—C1a96.8 (4)
Ti—Br12.5115 (7)C7—C6—C7a110.8 (4)
Cg1—Ti—Cg1a121.32 (9)Pr1—C1—C615.5 (3)
Br1—Ti—Br1a96.87 (3)Pr1—Pr1a65.8 (3)
Cg1 and Cg1a are the centroids defined by atoms C1–C5 and C1a–C5a, respectively. Pr1 and Pr1a are the ring planes defined by atoms C1–C5 and C1a–C5a, respectively [Symmetry code: (a) 2 - x, y, 3/2 - z].
 

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