Titanium(IV) chloride complexes with chiral tetraaryl-1,3-dioxolane-4,5- dimethanol ligands as a new type of catalysts of ethylene polymerization

Article abstract of DOI:10.1007/s11172-006-0121-6

Titanium complexes of chiral ligands, (4R,5R)-2,2-dimethyl-α,α, α′,α′-tetraphenyl-1,3-dioxolane-4,5-dimethanol and its structural analogs, activated by polymethylalumoxane catalyze ethylene polymerization with an activity from 3 to 530 (kg polyethylene) (

Full text of DOI:10.1007/s11172-006-0121-6

2348
Russian Chemical Bulletin, International Edition, Vol. 54, No. 10, pp. 2348—2353, October, 2005
Titanium(IV) chloride complexes with chiral
tetraarylꢀ1,3ꢀdioxolaneꢀ4,5ꢀdimethanol ligands
as a new type of catalysts of ethylene polymerization
Yu. N. Belokon´,aꢀ S. Ch. Gagieva,b T. A. Sukhova,c A. B. Dmitriev,a K. A. Lyssenko,a N. M. Bravaya,c
B. M. Bulychev,b and D. Seebachd
aA. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
28 ul. Vavilova, 119991 Moscow, Russian Federation.
Fax: +7 (495) 135 5085. Eꢀmail: yubel@ineos.ac.ru
bDepartment of Chemistry, M. V. Lomonosov Moscow State University,
1 Leninskie Gory, 199992 Moscow, Russian Federation.
Fax: +7 (495) 932 8846. Eꢀmail: B.Bulychev@highp.chem.msu.ru; sgagieva@yandex.ru
cInstitute of Problems of Chemical Physics, Russian Academy of Sciences,
142432 Chernogolovka, Moscow Region, Russian Federation.
Fax: +7 (496) 515 5420. Eꢀmail: nbravaya@cat.icp.ac.ru
dLaboratory of Organic Chemistry, Department of Chemistry and Applied Biosciences,
Swiss Federal Institute of Technology,
ETHꢀZurich, 10 WolfgangꢀPauliꢀStrasse, CHꢀ8093 Zurich, Switzerland.
Eꢀmail: seebach@org.chem.ethz.ch
Titanium complexes of chiral ligands, (4R,5R)ꢀ2,2ꢀdimethylꢀα,α,α´,α´ꢀtetraphenylꢀ1,3ꢀ
dioxolaneꢀ4,5ꢀdimethanol and its structural analogs, activated by polymethylalumoxane cataꢀ
lyze ethylene polymerization with an activity from 3 to 530 (kg polyethylene) (mol Ti h atm)–1
.
An increase in the bulk of the aryl substituents results in a decrease in the catalytic activity of
the complexes.
Key words: titanium chloride, chiral ligands, structure, homogeneous catalysts, polymerꢀ
ization, ethylene, polyethylene.
The invention of new highly efficient catalysts for oleꢀ
methanol (TADDOL) ligands are known14—16 to be
unique catalysts for the C—C bond formation in the nuꢀ
cleophilic addition to electrophiles and in the Diels—Alder
reaction. The analogy with the formation of C—C bonds
upon olefin polymerization suggests that this type of comꢀ
plexes would catalyze equally efficiently synthesis of polyꢀ
ethylene (PE) and polypropylene with high molecular
mass. The reason is that the chain transfer reactions reꢀ
sulting in a lower molecular masses of the polymer would
be retarded due to the steric strain created by the bulky
phenyl substituents in the tetraaryldioxolanedimethanol
ligands.
fin polymerization based on Group VIII transition metal
complexes with diimine ligands1 has stimulated intensive
development of the field of research referred to as "postꢀ
metallocene" catalysis.2—4 The main problems solved
within the framework of this approach include the search
for new ligands that change the geometry and the elecꢀ
tronic properties of complexes and the preparation of comꢀ
plexes with metal atoms other than those used previꢀ
ously.1—3 Among the most vivid results obtained by now,
mention should be made of the synthesis of catalysts with
the oxoimine type of ligands and a Group IV metal atom
as the complexing center,5 catalysts involving chromium,6
catalysts for copolymerization of hexꢀ1ꢀene with ethylꢀ
ene,7 and some others.8—13
The use of complexes with chiral ligands in olefin
polymerization appears rather attractive and topical. Preꢀ
sumably, these substances would be demanded for the synꢀ
thesis of stereoregular polypropylene and oligomerization
or copolymerization of polar and nonpolar monomers.
Transition metal complexes (especially TiIV comꢀ
plexes) with 2,2,R,R´ꢀtetraarylꢀ1,3ꢀdioxolaneꢀ4,5ꢀdiꢀ
This study deals with the catalytic properties of the
titanium complexes with chiral polydentate ligands, viz.,
(4R,5R)ꢀ2,2ꢀdimethylꢀα,α,α´,α´ꢀtetraphenylꢀ1,3ꢀdioxoꢀ
laneꢀ4,5ꢀdimethanol and its structural analogs.
Results and Discussion
Ligands 1—3 were synthesized by the known proceꢀ
dure using the reaction of arylmagnesium bromides with
tartaric acid esters.17,18 Then the dilithium alkoxides obꢀ
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2275—2280, October, 2005.
1066ꢀ5285/05/5410ꢀ2348 © 2005 Springer Science+Business Media, Inc.

TiIV complexes as catalysts for C2H4 polymerization Russ.Chem.Bull., Int.Ed., Vol. 54, No. 10, October, 2005
2349
C(12)
C(8)
tained from compounds 1—3 on treatment with BuLi in
hexane were mixed with 1 equiv. of TiCl4 (Scheme 1).
The resulting solutions of complexes 4—6 were used, withꢀ
out isolation or purification, as catalysts of ethylene polyꢀ
merization (in the presence of polymethylalumoxane
(MAO) as the coꢀcatalyst).
C(11)
C(10)
C(7)
C(2)
C(3)
C(6)
C(5)
C(4)
C(1)
C(9)
O(1)
C(13´)
O(3´)
O(3)
O(2)
C(13)
C(18´)
Scheme 1
O(2´)
C(18)
O(4)
O(5´)
C(16)
C(14)
C(17´)
C(14´)
C(15)
C(20)
C(15´)
O(6´)
C(16´)
O(5)
C(17)
C(19)
O(4´)
O(6)
C(19´)
C(21)
C(22)
C(20´)
O(7´)
C(21´)
C(23´)
O(7)
Ar = Ph, R = Me (1, 4); Ar = C6F5, R = Me (2, 5);
Ar = αꢀnaphthyl, RR = (CH2)5 (3, 6)
C(23)
C(22´)
The reaction of dibenzo[b,d]furanꢀ4,6ꢀdicarbaldehyde
with diisopropyl Lꢀtartrate gave 4,6ꢀbis[4,5ꢀdi(isopropꢀ
oxycarbonyl)ꢀ1,3ꢀdioxolanꢀ2ꢀyl]dibenzo[b,d]ꢀfuran (7),
which reacts with phenylmagnesium bromide to afford
4,6ꢀbis{4,5ꢀbis[hydroxy(diphenyl)methyl]ꢀ1,3ꢀdioxolanꢀ
2ꢀyl}dibenzo[b,d]furan (8) (Scheme 2).
Fig. 1. Structure of 4,6ꢀbis[4,5ꢀdi(isopropoxycarbonyl)ꢀ1,3ꢀ
dioxolanꢀ2ꢀyl]dibenzo[b,d]furan (7).
troscopy and singleꢀcrystal Xꢀray diffraction analysis of
the intermediate product 7 (Fig. 1, Table 1).
The main geometric parameters of compound 7 do
not differ much from the values expected for this class of
compounds. The dioxolane rings have envelope conforꢀ
The composition and structures of the products were
confirmed by data from elemental analysis, NMR specꢀ
Scheme 2

2350
Russ.Chem.Bull., Int.Ed., Vol. 54, No. 10, October, 2005
Belokon´ et al.
Table 1. Selected bond lengths (d) and bond angles (ω) in strucꢀ
ture 7
Y/kg PE (mol Ti)–1
3
2
Parameter
Value
Parameter
Value
150
4
Bond
d/Å
Bond
d/Å
O(1)—C(4)
O(1)—C(1)
1.386(6)
1.399(6)
C(3)—C(12)
C(4)—C(9)
C(5)—C(6)
C(6)—C(7)
C(7)—C(8)
C(9)—C(10)
C(10)—C(11)
C(11)—C(12)
1.405(6)
1.396(8)
1.372(8)
1.408(7)
1.374(7)
1.371(7)
1.380(8)
1.386(8)
100
50
O(2)—C(13) 1.422(7)
O(2)—C(14) 1.437(5)
O(2´)—C(13´) 1.391(7)
O(2´)—C(14´) 1.424(6)
O(3)—C(13) 1.416(7)
O(3)—C(15) 1.431(6)
O(3´)—C(15´) 1.413(6)
1
0
10
20
30
t/min
O(3´)—C(13´) 1.428(7) Angle
ω/deg
105.2(4)
102.4(4)
Fig. 2. Yield of polyethylene (Y) in ethylene polymerization
in the presence of a catalytic system 4—MAO ([Ti] =
3.2•10–6 mol L–1) vs. reaction time at 30 °C and differꢀ
ent AlMAO/Ti molar ratios: 200 (1), 310 (2), 385 (3), and
1050 (4).
C(1)—C(5)
C(1)—C(2)
C(2)—C(8)
C(2)—C(3)
C(3)—C(4)
1.368(7)
1.403(7)
1.395(8)
1.450(8)
1.386(8)
C(4)—O(1)—C(1)
C(13)—O(2)—C(14)
C(13´)—O(2´)—C(14´) 109.0(4)
C(13)—O(3)—C(15) 103.6(4)
C(15´)—O(3´)—C(13´) 107.8(5)
The catalytic activity of complex 4 in ethylene polyꢀ
merization was studied for concentrations ranging
from 1.1•10–3 to 1.6•10–4 mol L–1 at 30 °C. As shown
in Fig. 2, an increase in the AlMAO/Ti molar ratio
from 200 to 385 is accompanied by a gradual inꢀ
crease in the activity of the catalytic system from 60 to
500 kg PE (mol Ti h atm)–1. However, further increase
in this ratio to 1050 does not increase the activity
(430 kg PE (mol Ti h atm)–1). This results in a decrease in
the stability of system performance in the catalytic reacꢀ
tion. This type of behavior distinguishes complex 4 from
other known postꢀmetallocene and metallocene systems
whose activities and stabilities of performance increase
with an increase in the AlMAO/M ratio up to 2000—3000.
The dependence of the activity of the catalytic system
based on complex 4 on the polymerization temperaꢀ
ture is shown in Fig. 3. It can be seen that 30 °C is the
mations in which the C(13) and C(13´) atoms deviate
from the plane of the dioxolane fragments, the symmetry
plane of the dioxolane rings (without consideration of the
ester groups) actually coincides with the plane of the
dibenzofuran system (see Fig. 1). The carboxylate subꢀ
stituents in the dioxolane rings occupy axial positions.
The hydrogen atom at the chiral C(13) center is synperiꢀ
planar with respect to the oxygen atom of the dibenzofuran
system, whereas the hydrogen atom at C(13´) is antiꢀ
periplanar. This type of arrangement of the dioxolane
fragments gives rise to a number of contracted intraꢀ
molecular C—H...O contacts (the H...O distances are
2.42—2.44 Å).
Presumably, the positions and the conformation of
the dioxolane rings in ligand 8 are retained the same as in
ester 7.
Binuclear complex 9 was prepared by a procedure simiꢀ
lar to that used to synthesize mononuclear complexes
4—6 (see Scheme 2).
R/kg PE (mol Ti)–1 ([C2H4])–1
Ethylene polymerization was carried out in the presꢀ
ence of mononuclear titanium(IV) complexes 4—6 and
binuclear complex 9. The catalytic activity was estimated
without separation of LiCl; thus, possible changes in the
composition and structures of complexes upon isolation
and storage can be avoided.
1600
2
3
1200
1
800
Since in some cases the kinetics of ethylene absorpꢀ
tion had an induction period due to the low rate of formaꢀ
tion of the active sites and catalyst deactivation processes,
the catalytic activity of the system was estimated in terms
of two parameters, namely, the integral activity (A) exꢀ
pressed in kg PE (moles of the catalyst h atm)–1 and the
rate of ethylene absorption (R), which takes into account
different ethylene concentrations in the solution and the
change in the concentration with temperature and exꢀ
4
400
0
10
20
30
t/min
Fig. 3. Rate of ethylene absorption (R) in the presence of a
catalytic system 4—MAO ([Ti] = 3.2•10–6 mol L–1, AlMAO/Ti =
310 mol mol–1) vs. reaction time at different reaction temperaꢀ
tures: 20 (1), 30 (2), 60 (3), and 70 °C (4).
pressed in kg PE (mol Ti)–1 ([C2H4])–1
.

TiIV complexes as catalysts for C2H4 polymerization Russ.Chem.Bull., Int.Ed., Vol. 54, No. 10, October, 2005
2351
Y/kg PE (mol Ti)–1
120
Y/kg PE (mol Ti)–1
5
9
25
2
100
80
60
40
20
0
1
20
15
10
5
4
6
5
10
15
20
25
t/min
0
10
20
30
t/min
Fig. 4. Yield of polyethylene (Y ) in ethylene polymerization in
the presence of catalysts 4—6 and 9 vs. reaction time at 30 °C
([Ti] = 3.2•10–6 mol L–1, AlMAO/Ti = 1050 mol mol–1).
Fig. 5. Yield of polyethylene (Y ) in the presence of a catalytic
system 9—MAO vs. reaction time on direct introduction of the
catalyst into the MAOꢀcontaining reaction medium (1), and
after catalyst preꢀactivation by keeping it in a toluene solution
with MAO for 3.5 h (2) (polymerization temperature 30 °C,
temperature of choice. At 60 °C, catalyst deactivaꢀ
tion becomes noticeable (the integral activity is
240 kg PE (mol Ti h atm)–1), while at 70 °C, deactivation
predominates (the activity is 40 kg PE (mol Ti h atm)–1).
The activities of the catalytic systems obtained from
complexes 4—6 and 9 are compared in Fig. 4. It can
be seen that the activities of compounds 4 and 5 do not
differ much (530 and 650 kg PE (mol Ti h atm)–1, respecꢀ
tively), although the system based on complex 5 is
more stable. The step to complex 6 is accompanied
by an increase in steric crowding at the metal center
and results in a sharp decline of the catalyst activity
(170 kg PE (mol Ti h atm)–1). Binuclear complex 9
occupies an intermediate position (its activity is
290 kg PE (mol Ti h atm)–1). Thus, in terms of the activꢀ
ity in the ethylene polymerization, the complexes can be
arranged in the following sequence: 5 > 4 > 9 > 6.
The catalytic properties of binuclear complex 9 disꢀ
play some specific features. At high concentration of the
complex and low AlMAO/Ti molar ratio, the rate of forꢀ
mation of catalytic sites is an essential factor. This is
apparently responsible for the presence of an induction
period in the polymerization. To confirm this hypothesis,
we carried out the following experiments. In one of them,
ethylene polymerization was carried out over a catalytic
system 9—MAO at high catalyst concentration (1.5•10–3
mol L–1) and with its activation directly in the reaction
medium (AlMAO/Ti = 100 mol mol–1). In the second
experiment, the catalyst was dissolved together with MAO
and the preactivated catalyst was kept for 3.5 h before
injection into the reactor. The kinetics of ethylene polyꢀ
merization with these systems is shown in Fig. 5. It can be
seen that the former catalytic system shows a substantial
induction period and, during the polymerization, the rate
of monomer absorption gradually increases. In the secꢀ
ond catalytic system, polymerization proceeds at a conꢀ
stant rate.
pC H4 = 0.89 atm, toluene, [Ti] = 1.5•10–3 mol L–1, AlMAO/Ti =
2
100 mol mol–1).
although its activity is 1.5—2 times lower than that obꢀ
served with a catalytic system 4—MAO, all other factors
being the same.
As can be seen from Fig. 6, the catalyst involving
complex 9 exhibits rather stable performance at polymerꢀ
ization temperatures of 25—60 °C (curves 1—3), but is
deactivated almost completely over a period of 5 min at
70 °C (curve 4).
The IR spectra of the polymers obtained with any of
the catalysts exhibit bands at 908 and 995 cm–1, which are
indicative of chain transfer through βꢀH elimination and
hydrogen migration to the Ti atom or to the monomer,
which yields terminal vinyl groups.19 The fact that PE is
mainly linear and has a relatively high molecular mass is
R/kg PE (mol Ti)–1 ([C2H4])–1
700
3
2
600
500
400
300
200
100
4
1
0
5
10
15
20
t/min
Fig. 6. Rate of ethylene absorption (R) in the presence of a
catalytic system 9—MAO vs. reaction time at different temperaꢀ
tures: 25 (1), 50 (2), 60 (3), and 70 °C (4) (pC H = 0.89 atm,
It is noteworthy that binuclear complex 9 has a much
higher thermal stability than the mononuclear analog 4,
2
4
toluene, [Ti] = 1.74•10–5 mol L–1, AlMAO/Ti = 52 mol mol–1).

2352
Russ.Chem.Bull., Int.Ed., Vol. 54, No. 10, October, 2005
Belokon´ et al.
warming to room temperature, the reaction mixture was reꢀ
fluxed for 2 h and neutralized with a saturated solution of NH4Cl.
The organic layer was separated, the solvent was evaporated,
and the residue was recrystallized from methanol. Yield 0.19 g
(14%), dec.p. 232 °C, [α]D +159.3 (c 0.5, CHC13). Found (%):
C, 80.71; H, 5.42. C70H56O9. Calculated (%): C, 80.75; H, 5.42.
indicated by high melting points of the obtained samples
(140—142 °C).
Thus, we synthesized a new class of titanium cheꢀ
lates active in ethylene polymerization upon activaꢀ
tion by MAO. According to the results obtained, their
performance is at the level of the soꢀcalled active
catalysts (against the activity scale introduced previꢀ
ously20 for postꢀmetallocene type chelates, which is
~200 kg PE (mol Ti h atm)–1). The relatively high stabiliꢀ
ties of complexes 5 and 9, especially 9, under polymerizaꢀ
tion conditions at high temperatures provides grounds for
believing that these catalysts can be used in block copolyꢀ
merization of ethylene with less active (for example,
higher) olefins.
3
1H NMR, δ: 7.82 (d, 2 H, J = 7.5 Hz); 7.61 (m, 8 H); 7.44 (t,
4 H, 3J = 7.5 Hz); 7.39—7.07 (m, 32 H); 6.14 (s, 2 H); 5.54 (d,
2 H, 3J = 4.0 Hz); 5.35 (d, 2 H, 3J = 4.4 Hz); 3.54, 2.41 (both s,
2 H each). 13C NMR, δ: 154.18, 145.40, 145.36, 144.52, 144.16
(2 C each); 128.50, 128.42 (4 CH each); 128.22, 128.17 (2 CH
each); 127.90 (2 C); 127.38 (t); 127.17, 127.14 (2 CH each);
126.90, 124.79 (2 C each); 123.25, 122.05 (2 CH each); 121.58
(2 C); 102.47, 82.02, 81.22, 79.65, 79.27 (2 CH each).
Synthesis of complexes 4—6 and 9 (general procedure).
A 10 M solution of butyllithium in hexane (0.042 mL, 0.42 mmol)
was added dropwise with stirring under argon to a cooled
(–78 °C) solution of ligand 1—3 or 8 (0.20 mmol) in toluene
(10 mL). The temperature of the reaction mixture was slowly
brought to ambient temperature, the mixture was stirred for 4 h
and cooled to –78 °C. A solution of TiCl4 (0.024 mL, 0.20 mol)
was added and the mixture was again warmed to ambient temꢀ
perature. After 3 h, the reaction mixture was filtered, the solvent
was evaporated, and the product was recrystallized from toluene.
Complex 4. Yield 0.110 g (94%), m.p. 294 °C, [α]D –90.3
(c 1, toluene). Found (%): C, 63.79; H, 4.69; Cl, 12.20; Ti, 8.05.
C31H28Cl2O4Ti. Calculated (%): C, 63.83; H, 4.84; Cl, 12.16;
Experimental
The complexes were synthesized under argon. Tetrahydroꢀ
furan, dichloromethane, toluene, isopropyl alcohol, hexane, and
ethyl acetate (chemically pure grade) were additionally purified
according to published procedures;21 TiCl4 (Fluka) was distilled
under argon; SiO2 and dibenzo[b,d]furan (Fluka) were used as
received. Diisopropyl Lꢀtartrate and dibenzo[b,d]furanꢀ4,6ꢀ
dicarbaldehyde were prepared by a previously described proꢀ
cedure.22
The NMR spectra of solutions of ligands in CDCl3 were
recorded on Bruker WPꢀ200 and Bruker AMХꢀ400 instruments
and IR spectra, on a MagnaꢀIR 750 spectrophotometer. The
optical rotation was measured on a Perkin—Elmer 241 polarimꢀ
eter. The elemental analysis was performed on Carlo Erbaꢀ1106
and Carlo Erbaꢀ1108 instruments.
(4R,5R)ꢀ2,2ꢀDimethylꢀα,α,α´,α´ꢀtetraphenylꢀ1,3ꢀdioxoꢀ
laneꢀ4,5ꢀdimethanol (1) was prepared by a known procedure,17
m.p. 193 °C (cf. Ref. 17: m.p. 192 °C).
(4R,5R)ꢀ2,2ꢀDimethylꢀα,α,α´,α´ꢀtetrakis(pentafluoropheꢀ
nyl)ꢀ1,3ꢀdioxolaneꢀ4,5ꢀdimethanol (2) was prepared by a pubꢀ
lished procedure,18 m.p. 106 °C (cf. Ref. 18: m.p. 104—105 °C).
(2R,3R)ꢀ1,4ꢀDioxaspiro[4.5]decaneꢀα,α,α´,α´ꢀtetraꢀ
kis(1ꢀnaphthyl)ꢀ2,3ꢀdimethanol (3) was prepared by a known
procedure,17 m.p. 186 °C (cf. Ref. 17: m.p. 192 °C).
1
Ti, 8.21. H NMR (tolueneꢀd8), δ: 7.20—7.25 (m, 20 H); 4.80
(s, 2 H, CH); 1.57 (s, 6 H, Me).
Complex 5. Yield 0.164 g (87%), m.p. 225 °C, [α]D +18.4
(c 1, toluene). Found (%): C, 39.29; H, 0.92; Cl, 7.29; Ti, 4.95.
C
31H8Cl2F20O4Ti. Calculated (%): C, 39.48; H, 0.85; Cl, 7.52;
Ti, 5.08. 1H NMR (tolueneꢀd8), δ: 4.69 (s, 2 H, CH); 1.43
(s, 6 H, Me).
Complex 6. Yield 0.124 g (76%), m.p. 271 °C, [α]D –39.3
(c 1, toluene). Found (%): C, 72.79; H, 4.69; Cl, 8.56; Ti, 5.75.
C50H40Cl2O4Ti. Calculated (%): C, 72.93; H, 4.86; Cl, 8.63;
Ti, 5.80. 1H (tolueneꢀd8), δ: 7.16—7.68 (m, 28 H); 4.70 (s, 2 H,
CH); 1.50—1.74 (m, 10 H, CH2).
Complex 9. Yield 0.197 g (78%), m.p. 294 °C. Found (%):
C, 65.72; H, 4.04; Cl, 11.07; Ti, 7.65. C70H52Cl4O9Ti2. Calcuꢀ
lated (%): C, 65.96; H, 4.11; Cl, 11.13; Ti, 7.51. 1H NMR
3
4,6ꢀBis[4,5ꢀdi(isopropoxycarbonyl)ꢀ1,3ꢀdioxolanꢀ2ꢀyl]diꢀ
benzo[b,d]furan (7). A solution of dibenzo[b,d]furanꢀ4,6ꢀ
dicarbaldehyde (1.00 g, 4.46 mmol) in benzene (20 mL),
diisopropyl Lꢀtartrate (1.88 mL, 8.92 mmol), and TsOH
(0.0154 g, 0.01 mmol) were refluxed for 48 h with the
Dean—Stark trap. The reaction mixture was washed with a satuꢀ
rated solution of NaHCO3, the solvent was evaporated, and the
product was recrystallized from methanol. Yield 0.7 g (24%),
(tolueneꢀd8), δ: 7.78 (d, 2 H); 7.61 (m, 8 H); 7.42 (t, 4 H, J =
7.5 Hz); 7.39—7.07 (m, 32 H); 6.14 (s, 2 H); 5.54 (d, 2 H, 3J =
4.0 Hz); 5.35 (d, 2 H, 3J = 4.4 Hz); 2.38 (s, 2 H).
Solutions of complexes used for polymerization were preꢀ
pared by the following procedure. Butyllithium (0.042 mL,
0.42 mmol) was added dropwise with stirring under argon to a
cooled (–78 °C) solution of ligand 1—3 and 8 (0.20 mmol) in
heptane (10 mL). The temperature of the reaction medium was
slowly brought to ambient temperature, the mixture was stirred
for 4 h and cooled to –78 °C, and a solution of TiCl4 (0.024 mL,
0.20 mol) was added. This mixture was used without additional
treatment.
Ethylene polymerization. The catalytic polymerization of
ethylene was carried out in toluene and heptane (special purity
grade), which were purified from possible impurities by the proꢀ
cedure standard for this process.23 Polymethylalumoxane (Witco)
was used as a 10% toluene solution. Argon and ethylene (special
purity grade) were dried by passing through a column packed
with 5A molecular sieves.
25
m.p. 103—105 °C, [α]D –49.5 (c 1, CHC13). Found (%):
C, 62.18; H, 6.07. C34H40O13. Calculated (%): C, 62.19; H, 6.14.
1H NMR, δ: 7.98 (d, 2 H, 3J = 7.5 Hz); 7.83 (d, 2 H, 3J =
3
7.3 Hz); 7.39 (t, 2 H, 3J = 7.3 Hz, J = 7.5 Hz); 6.85 (s, 2 H.);
3
5.18 (br.m, 4 H); 4.98, 4.85 (both d, 2 H each, J ≈ 3 Hz); 1.36
(d, 12 H, 3J = 5.8 Hz); 1.28, 1.23 (both d, 6 H each, 3J = 6.8 Hz).
4,6ꢀBis{4,5ꢀbis[hydroxy(diphenyl)methyl]ꢀ1,3ꢀdioxolanꢀ2ꢀ
yl}dibenzo[b,d]furan (8). A solution of ester 7 (0.9 g, 1.37 mmol)
in THF (30 mL) was added with cooling (0 °C) and stirring
under argon to a solution of PhMgBr prepared from Mg (0.29 g,
12 mmol) and PhBr (1.88 g, 12 mmol) in THF (70 mL). After

TiIV complexes as catalysts for C2H4 polymerization Russ.Chem.Bull., Int.Ed., Vol. 54, No. 10, October, 2005
2353
All operations for the setup assembly and the procedures for
preparation and injection, into the reaction vessel, of the comꢀ
plexes assayed and ethylene, and measurements of polymerizaꢀ
tion kinetics are similar to those described previously.24 After
complete dissolution of ethylene in a solution of the assayed
complex in toluene or heptane, polymerization was initiated by
introducing a solution of the catalyst into the reactor and
quenched with a 10% solution of HCl in ethanol. The polymeric
product was filtered off, washed with ethanol and water, and
dried in vacuo at 50—60 °C to a constant weight.
7. R. Souane, F. Isel, F. Peruch, and P. J. Lutz, C. R. Chim.,
2002, 5, 43.
8. E. Y.ꢀX. Chen and T. J. Marks, Chem. Rev., 2000, 100, 1391.
9. L. Resconi, L. Cavallo, A. Fait, and F. Piemontesi, Chem.
Rev., 2000, 100, 1253.
10. T. Matsugi, S. Matsui, S. Kojoh, Y. Takagi, I. Inoue,
T. Nakano, T. Fujita, and N. Kashiwa, Macromolecules,
2002, 35, 4880.
11. S. Matsui, M. Mitani, J. Saito, Y. Tohi, H. Makio,
N. Matsukawa, Y. Takagi, K. Tsuru, M. Nitabaru,
T. Nakano, H. Tanaka, N. Kashiwa, and T. Fujita, J. Am.
Chem. Soc., 2001, 123, 6847.
The Xꢀray diffraction experiment for compound 7 (C34H40O13
)
was carried out at 110 K on a Smart CCD 1000K diffractometer
(MoꢀKα radiation, graphite monochromator, ωꢀscan mode,
12. U. Weiser and H.ꢀH. Brintzinger, in Organometallic Cataꢀ
lysts and Olefin Polymerization, Eds R. Blom, A. Follestad,
E. Rytter, M. Tilset, and M. Yestens, SpringerꢀVerlag, Berlin,
2001, 3.
13. D. Coevoet, H. Cramail, and A. Deffieux, Macromol. Chem.
Phys., 1998, 199, 1451.
14. K. Gottwald and D. Seebach, Tetrahedron, 1999, 55, 723.
15. S. M. Moharram, G. Hirai, K. Koyama, H. Oguri, and
M. Hirama, Tetrahedron Lett., 2000, 41, 6669.
16. D. Seebach, A. K. Beck, R. Imwinkelried, S. Roggo, and
A. Wonnacott, Helv. Chim. Acta, 1987, 70, 954.
17. A. K. Beck, B. Bastani, D. A. Plattner, W. Petter,
D. Seebach, H. Braunshweiger, P. Gysi, and L. LaVeccia,
Chimia, 1991, 45, 238; D. Seebach, A. K. Beck,
R. Imwinkelried, S. Roggo, and A. Wonnacott, Helv. Chim.
Acta, 1987, 70, 954.
2θ
< 54°). The crystals are monoclinic, a = 9.944(2) Å,
max
b = 18.315(5) Å, c = 10.470(2) Å, β = 116.099(11)°, V =
1712.5(7) Å3, dcalc= 1.274 g cm–3, M = 656.66, F(000) = 696,
µ = 0.98 cm–1, Z = 2 (Z´ = 1), space group P21. Of the total
6432 measured reflections (Rint = 0.0334), 3900 independent
reflections were used in the subsequent calculations and in the
refinement. The structure was solved by the direct method and
refined by leastꢀsquares method in the fullꢀmatrix anisotropic
approximation for F 2hkl. The hydrogen atoms were located from
difference electron density Fourier syntheses and included in
the refinement in the anisotropic approximation. The final Rꢀfacꢀ
tors are R = 0.0363 over 2035 reflections with I > 2σ(I ),
wR2 = 0.0929, GOF = 1.099 for all reflections. All calculations
were carried out on a SHELXTL PLUS program package.25
18. A. Hafner, R. O. Duthaler, R. Marti, G. Rihs, P. Rotheꢀ
Streit, and F. Schwarzenbach, J. Am. Chem. Soc., 1992,
7, 2321.
19. A. I. Tarutina and F. O. Pozdnyakova, Spektral'nyi analiz
polimerov [Spectral Analysis of Polymers], Khimiya,
Leningrad, 1986, 248 (in Russian).
This work was supported by the Russian Foundation
for Basic Research (Projects No. 04ꢀ03ꢀ08018 ofi_a and
No. 05ꢀ03ꢀ32771ꢀA).
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Received November 18, 2004;
in revised form October 24, 2005