2
116
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 10, October, 2007
Kvashina et al.
Sample 2 was prepared for measuring the IR spectrum by its
presence of the OD group in the composition of molꢀ
ecule 2 is a result, most likely, of the deuterium exchange
of the D atoms in the DCl molecule with the H atoms of
the OH group. This confirms that the OH group is a
component of molecule 1. The mechanism of the reacꢀ
tion of molecular oxygen with ditoluenetitanium(0) afꢀ
fording the OH group in the composition of compound 1
remains unclear.
triturating in Nujol in an inert atmosphere, and during this
procedure a minor amount of toluene that remained after deꢀ
canting was evaporated.
IR spectra were recorded on a Specord IRꢀ75 spectrophoꢀ
tometer.
Magnetic susceptibility was measured by the Faraday
4
method at 80—293 K in an interval of field intensity of 1—10
kOe in an inert atmosphere. The sample was also prepared in an
inert atmosphere.
Ethylene polymerization was carried out at 18.5 °C under a
constant ethylene pressure of 540 Torr (total volume of the setup
The IR spectrum of compound 2 contains no AB at
–
1
6
3100, 1600, and 1500 cm characteristic of aromatic
compounds. The observed AB belong to the C=C double
4
80 mL, volume of the reaction flask 80 mL). To prepare the
6
bonds and the C—C and C—H ordinary bonds. These
polymerization catalyst, a solution of ditoluenetitanium(0)
groups can be formed due to the C—C bond cleavage in
the arene ring and its transformation into the linear fragꢀ
ment (L).
–
5
–1
(
7 mL, 2•10 (mole of Ti) mL ) was placed in the reaction
flask and oxidized similarly to the synthesis of compound 1.
Ethylene was fed into the reaction flask with magnetic stirring.
The amount of absorbed ethylene was measured manometrically.
The IR spectrum of the gaseous products of the reacꢀ
tion of compound 1 with DCl was measured, ν/cm–
1
:
Results and Discussion
2800—3000 (ν(H—Cl) s, 2270 (ν(C—D)) s. The intense
–
1
AB at 2270 cm is assigned to stretching vibrations of the
7
Bisarene titanium(0) complexes are diamagnetic
compounds, which are highly sensitive to oxygen and
C—D bond of the aromatic ring. Therefore, the interacꢀ
tion of compound 1 with DCl is accompanied by deuteraꢀ
tion exchange involving the H atoms of the arene ring.
In the absence of compound 1, no deuterium exchange of
the H atoms of the arene ring with a DCl molecule ocꢀ
curs. It can be assumed that the toluene molecule is actiꢀ
5
well soluble in toluene. The solutions are redꢀcolored
(
λmax = 512 nm).
Upon the slow oxygen supply, we obtained an interꢀ
mediate product of ditoluenetitanium(0) oxidation with
oxygen (1). Compound 1 is a black substance insoluble in
toluene, and it becomes lighter in oxygen excess to form
the titanium(IV) compound. To determine the oxidation
state of titanium in compound 1, we measured its magꢀ
netic susceptibility. The results of the measurement indiꢀ
cate that compound 1 is diamagnetic. It was also found
that compound 1 is readily hydrolyzed with water to evolve
II
vated in the system due to complex formation with Ti .
However, after evacuation to remove the solvent, the
IR spectrum of solid product 1 contained no AB of toluꢀ
II
ene. It is most likely that the Ti complex with toluene
has a low complex formation constant and toluene is
removed under the conditions of sample preparation.
Thus, the composition of synthesized catalyst 1 for ethylꢀ
ene polymerization can be expressed by the formula
1
.0 mole of H per 1 mole of Ti. These facts suggest that
product 1 is a titanium(II) compound.
2
II
OH—Ti —L•PhСН , where L is the linear fragment conꢀ
3
The IR spectrum of compound 1 was measured
in an inert atmosphere, ν/cm : 1600 (δ(OH)) m,
450 (ν(OH)) m. The spectrum also contains a series of
taining the C=C multiple bonds and the C—C and C—H
ordinary bonds, which are formed due to the C—C bond
cleavage of the aromatic ring.
–
1
3
weak absorption bands (AB) that cannot be analyzed reliꢀ
ably. The observed AB attributed to vibrations of the
OH group suggest the presence of this group in the comꢀ
position of compound 1.
The data on ethylene polymerization in the presence
of product 1 are shown in Fig. 1.
p/Torr
To reveal the composition of compound 1, we studied
the gaseous and solid products of its reaction with gaseous
DCl. The reaction turned the solid product yellow
from black. Yellow product 2 together with toluene is
5
0
40
–
2
easily distilled in a vacuum of 10 Torr at room temꢀ
perature. Toluene was decanted in vacuo, and its resiꢀ
dues were removed when triturating sample 2 in an
inert atmosphere. In air Tiꢀcontaining compound 2 deꢀ
composes rapidly. The IR spectrum of solid product 2
3
2
1
0
0
0
–
1
was measured in an inert atmosphere, ν/cm
:
0
3
1
1
8
350 (ν(O—H)) m, 2500 (ν(O—D)) m, 1590 (ν(C=C)) s,
10
20
30
40
50
t/min
410 (δ(=CH )) m, 1250 (ν(C—C)) w, 1180 (β(CCH)) m,
2
Fig. 1. Ethylene consumption during its polymerization in the
presence of catalyst 1 at 18.5 °С (pressure in the system 540 Torr,
toluene (7 mL), 2•10–5 (mole of Ti) mL ).
110 (ν(C—Cl)) m, 1070 (δ(C—C)) w, 1000 (δ(CH)) m,
–1
60 (δ(Ti—OH)) s, 780 (δ(CH )) m, 720 (δ(CC)) s. The
2
Kvashina
