Crystal structure of η5-1-(tris(pentafluorophenyl)boranylmethyl)-2,3,4,5- tetramethylcyclopentadienyl-η5,η1-3,6-di-tert-butyl-9,10,11-trimethylbicyclo( 6.3.0)undeca-3-en-8,10-dienyl)titanium(IV), Ti(C50H48BF15)

Anke Spannenberg, Vladimir V. Burlakov, Uwe Rosenthal
2008 Zeitschrift für Kristallographie - New Crystal Structures  
C 50H48BF15Ti, monoclinic, P121/c1(no. 14), a =12.007(2) Å, b =19.511(4) Å, c =20.010(4) Å, b =98.90(3)°, V =4631.3 Å 3 , Z =4,R gt (F) =0.052, wR ref (F 2 ) =0.120, T =200 K. Source of material An amountofB(C 6 F 5 ) 3 (321 mg, 0.63 mmol) was dissolved in 10 ml of warm n-hexane under Ar. The obtained solution was filteredand added to ayellow-greenish filtrate of pentamethylcyclopentadienyl-trimethylcyclopentadienyl-cyclooctyne titanium(II) [1] (289 mg, 0.60 mmol) in 15 ml of warm n-hexane. The
more » ... warm n-hexane. The resulting mixture was allowed to stand in argon atmosphere at room temperature.In3days in the yellow solution the red-brownfine crystals were formed on the bottom and the walls of the vessel. The crystals were separated from the mother liquor by decanting, washed with n-hexane, and dried in vacuum to give 373 mg of the title complex.After repeated recrystallization from 20 ml of am ixture THF/n-hexane( 1:1, v/v)as malla mount of crystals well suited for X-ray structure analysis was obtained (m.p. 257-260°C, dec. under argon). Experimental details The hydrogenatoms (except those attached to C13, C14 and C18) were included at calculated positions and refined by using the riding model. The remaining Hatoms were refined isotropically. Discussion Ion pairs[Cp¢ 2ZrR] + [RB(C6F5)3]which are formedbythe abstraction of methyl anions from group 4d imethyl complexes Cp¢ 2 MMe 2 (M =T i, Zr; Cp¢ =s ubstituted or unsubstituted h 5cyclopentadienyl) with the strong Lewis acid B(C 6 F 5 ) 3 are highly active catalysts for the polymerization of a-olefins [2]. Metallocene olefin, alkyne and butadiene complexes undergo also asimilaractivation for the catalytic polymerization [3]. In the title crystal structure, the titanium(IV) is coordinated by the [Me 4C5-CH2-B(C6F5)3]ligand and shows the typical environment [4]. The most interesting feature is the formed trimethylcyclopentadienylcyclooctenyl ligand interacting unsymmetrically with the metal (d(Ti1-C13) =2 .222(3) Å, d(Ti1-C14) = 2.410(3) Å). From the Ti-C and the corresponding C-C bond distances (d(C13-C14) =1 .439(5) Å and d(C14-C15) = 1.379(5) Å)one can describethe interaction of this ligand by a s-Ti-C13 bond. The type of the structure is unprecedented. Duringthe reaction the hydrogen is shifted to the trimethylcyclopentadienylcyclooctyneligand giving atrimethylcyclopentadienylcyclooctenyl ligand. The remaining double bond does not coordinate to the metal. Crystal: brownprism, size 0.2 × 0.3 × 0.4 mm Wavelength: Mo Ka radiation (0.71073 Å) m:2 .80 cm −1 Diffractometer, scan mode: Stoe IPDS I, j 2qmax:5 2.32°N (hkl)measured, N(hkl)unique:1 6687, 9055 Criterion for Iobs, N(hkl)gt: Iobs >2s(Iobs),4504 N(param)refined:6 16 Programs: SHELXS-86 [5], SHELXL-93 [6] Table 1. Data collection and handling. Unauthenticated Download Date | 7/28/18 12:17 PM
doi:10.1524/ncrs.2008.0029 fatcat:i4tygblnibfrleyblto3vhn2ke