CRYSTAL STRUCTURE
47
Table 1. Crystallographic data and characteristics of Xꢀray
The synthesis of the 2ꢀmethylꢀ4ꢀparaꢀtolylꢀ1ꢀ
4dihydrocyclopenta[b]indole ligand (L) was described
in [12].
Synthesis of compound I. A precisely weighed porꢀ
tion of L (4.0 g, 15.6 mmol) was dissolved in toluene
(50.0 mL) with a small tetrahydrofuran (THF) addiꢀ
diffraction experiment for compound
I
FW
734.92
Crystal size, mm
Symmetry system
0.2 × 0.3 × 0.4
Triclinic
tive, and to this solution cooled down to –80°С, BuLi
Space group
P
1
in hexane (9.8 mL, 15.6 mmol, 1.6 M) was slowly
added dropwise. To the solution of the resulting lithꢀ
ium salt, (CH3)2SiCl2 (1.0 mL, 7.8 mmol) was added,
and the reaction mixture was stirred at room temperaꢀ
ture for 24 h. Then, the solution was decanted from a
LiCl precipitate and concentrated by removing the
solvent under vacuum. The product in the form of oil
was dissolved in toluene (50 mL), the solution was
Unit cell parameters:
a
, Å
, Å
9.252(2)
12.914(3)
15.619(3)
111.83(3)
81.03(3)
117.77(3)
1569(3)
2; 1.525
60.9
b
c
, Å
, deg
, deg
, deg
, Å3
α
β
cooled down to –80°С, and another portion of BuLi
γ
in hexane (11.1 mL, 1.6 M) was slowly added. The
mixture was slowly heated to room temperature,
stirred at this temperature for 2 h, and cooled again.
ZrCl4 (1.78 g, 7.8 mmol) was added to the cooled soluꢀ
tion, and the mixture was additionally stirred for 8 h at
room temperature. After removal of the solvent and
recrystallization from diethyl ether, a mixture of the
V
Z
μ
F
θ
;
ρcalc, g/cm3
, cm–1
(000)
range, deg
724
1.41–29.60
Index range
–11
≤
h
≤
11, –16
12
≤ k ≤ 15,
racꢀ and mesoꢀforms of compound I was obtained as
0 ≤ l ≤
orangeꢀbrown crystals (3.7 g, 79%). The fractionation
of crystals in an ether/hexane solution gave the pure
rac form (light brown crystals, 1.21 g, 26%) and the
pure meso form (orange crystals, 0.71 g, 16%).
Total number of measured
reflections
5252
Number of reflections with
I ≥ 2σ(I)
5242 (
R
int) = 0.0128
526
For racꢀC40H36Cl2N2SiZr anal. calcd. (%): C,
65.37; H, 4.93; N, 3.81; Cl, 9.64.
Number of refined parameꢀ
ters
GOOF on F2
Found (%): C, 65.25; H, 4.86; N, 3.94; Cl, 9.51.
0.879
Xꢀray diffraction analysis. The experimental data
for a light brown crystal of compound I were obtained
R
R
[
I
≥
2
σ
(
I
)]
R
1 = 0.0364, wR2 = 0.0961
1 = 0.0438, wR2 = 0.0991
0.487/–0.487
on an EnrafꢀNonius CAD4 automatic fourꢀcircle difꢀ
(all data)
R
fractometer (graphite monochromator, MoKα radiaꢀ
tion, θ/2θ scanning). The structure was solved by
Residual electron density
(max/min), e/Å3
direct methods with the use of the ARENꢀ88 crystalꢀ
lographic software [13]. Hydrogen atoms were found
from a difference Fourier synthesis. The structure was
refined by the fullꢀmatrix leastꢀsquares technique in
the anisotropic approximation for nonꢀhydrogen
atoms with the use of the SHELXLꢀ97 software [14].
Absorption was not taken into account.
There is no contact between the Zr and N atoms, and
this is also a common characteristic of heteroaromatic
zirconocenes. The molecule lies on the twofold crysꢀ
tallographic axis passing through the silicon and zircoꢀ
nium atoms. The nitrogen atoms in heterocycles are
arranged on the internal ring sides facing the zircoꢀ
nium atom. The N(1)–C(11) bond length in the pyrꢀ
role ring (1.384(6) Å) indicates the contribution of a
double bond and the presence of a positive charge on
the nitrogen atom. This, in its turn, leads to the deloꢀ
calization of a negative charge over the entire molecule
and, in particular, in the Cp ring. The C–C bond
lengths in Cp rings vary within 1.411–1.499 Å,
whereas in analogous bisꢀindenyl complexes II and
III, they are within 1.410–1.442 Å [1, 3, 4–9]. The
Selected crystal data and characteristics of Xꢀray
diffraction experiment for compound
I are given in
Table 1, and interatomic distances and bond angles are
listed in Table 2.
Polymerization of propylene was performed in the
presence of complex I in a steel highꢀpressure reactor
under vigorous stirring of a reaction mixture.
RESULTS AND DISCUSION
The molecular structure of complex
the figure. In the complex, the zirconium atom is tolyl rings of 56.1
placed between two η5(pentahapto) cyclopentadienyl and electronic interactions between them. Table 3, in
moieties. The molecule has characteristics typical of which selected structural parameters of complex are
I
in shown in torsion angles between the planes of the Cp and para
ꢀ
°
and 54.1 provide minimum steric
°
I
ansaꢀmetallocene complexes with short bridges. given in comparison with those of complexes II–V
,
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 1 2012
Dzhabieva
