Ansa-bridged η-cyclopentadienyl imido and amido derivatives of titanium, zirconium and molybdenum

Article abstract of DOI:10.1016/S0022-328X(97)00516-0

An improved synthesis of the ligand precursor {[C₅H₄(SiMe₃)](CH₂) ₃N(SiMe₃)₂} is described. It has been used to prepare the compounds {Ti[η:σ-C₅H₄(CH₂) ₃N(SiMe₃)]Cl₂}, {Ti[η-C₅H₄(CH₂) ₃(μ-N)]Cl}₂, {Zr[η:σ-C₅H₄(CH₂) ₃N(SiMe₃)](SMe₂)Cl₂}, {Zr[η:σ-C₅H₄(CH₂) ₃N(SiMe₃)]Cl₂} and {Mo[η:σ-C₅H₄(CH₂) ₃N(SiMe₃)](PMe₃)Cl₂}. The zirconium compounds together with methylaluminoxane act as catalysts for ethylene and propylene polymerisation.

Full text of DOI:10.1016/S0022-328X(97)00516-0

Journal of Organometallic Chemistry 551 Ž1998. 133–138
Ansa-bridged h-cyclopentadienyl imido and amido derivatives of
1
titanium, zirconium and molybdenum
2
)
2
Pedro T. Gomes , Malcolm L.H. Green , Ana M. Martins
Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, USA
Received 19 April 1997; received in revised form 29 June 1997
Abstract
An improved synthesis of the ligand precursor ÄwC H ŽSiMe .xŽCH . NŽSiMe . 4 is described. It has been used to prepare the
5
4
3
2
3
3 2
compounds ÄTiwh:s-C H ŽCH . NŽSiMe .xCl 4, ÄTiwh-C H ŽCH . Ž m-N.xCl4 , ÄZrwh:s-C H ŽCH . NŽSiMe .xŽSMe .Cl 4, ÄZrwh:s-
5
4
2
3
3
2
5
4
2
3
2
5
4
2
3
3
2
2
C H ŽCH . NŽSiMe .xCl 4 and ÄMowh:s-C H ŽCH . NŽSiMe .xŽPMe .Cl 4. The zirconium compounds together with methylalumi-
5
4
2
3
3
2
5
4
2
3
3
3
2
noxane act as catalysts for ethylene and propylene polymerisation. q 1998 Elsevier Science S.A.
Keywords: Zirconium; Titanium; Molybdenum
1
. Introduction
sodium cyclopentadienide giving an isomeric mixture of
C H4.ŽCH2 .3 SiMe3.2 x 2. Addition to 2 of t-butyl
lithium followed by Me SiCl gives the desired com-
w
Ž
N
Ž
5
Recently we reported the synthesis of the compound
3
Ä
wC H4ŽSiMe3
.
xŽ
CH2 .3
N
Ž
SiMe3.2
4
and showed that it
pound
ture of isomers. The reaction sequence is shown in the
Scheme 1. The overall yield of from
N 3 as a mix-
ÄwC H4ŽSiMe3.xŽCH2 .3 ŽSiMe3.2 x4
5
5
reacted readily with niobium pentachloride to give the
ansa-bridged h-cyclopentadienyl-imido derivative
3
Ä
Nbwh:s-C H4ŽCH2 .3NxCl24 w1x. In view of the current
wBrŽCH2 .3NH xBr was reproducibly 50–55%. The
5
3
interest in ansa-bridged h-cyclopentadienyl-amido
compounds of the group IV metals as catalyst precur-
sors for a-olefin polymerisation w2–12x we have ex-
compound 3 was stored under dinitrogen at 08C without
noticeable deterioration.
Treatment of TiCl4 in toluene with 3 gave orange
crystals for which the analytical and spectroscopic data
plored further the synthetic potential of the ligand pre-
cursor
below. A preliminary report of part of this work has
been communicated w13x.
Ä
wC H4ŽSiMe3
.
x
Ž
CH2 .3
N
Ž
SiMe3.2
4
, as described
correspond to the com pound
Ä T iwh : s -
5
C H4ŽCH2 .3 xCl24 4. The characterising data
N
Ž
SiMe3
.
5
for 4 and for all the other new compounds described
below are given in Table 1 and will only be discussed
further where the interpretation is not straightforward.
An attempt to determine the crystal structure of 4 by
X-ray diffraction showed the presence of disorder but
nonetheless allowed the location of the atoms corre-
sponding to the structure shown in the Scheme 2 w14x.
2
. Results and discussion
Treatment of wBr
lents of M e Si
Br
CH2 .3
ŽCH2 .3NH xBr with three equiva-
3
Ž
.
SO CF
and Et N gave
3
3
3
3
Ž
N
Ž
SiMe3.2 1 which was then reacted with
The elimination of SiMe Cl from 4 occurs readily in
3
toluene at 608C to give
. The dimeric structure of 5 is confirmed by the H
ÄTiwh-C H4ŽCH2 . Ž m-N.xCl42
5
3
1
5
NMR spectrum that shows diastereotopic signals for the
aliphatic chain protons.
)
Corresponding author.
Dedicated to Prof. Peter Maitlis on the occasion of his 65th
1
Treatment of wZrCl ŽSMe2 .2 x w15x with 3 gave white
4
birthday and in recognition of his outstanding contributions to
organo-transition metal chemistry.
crystals of N SiMe SMe Cl
ÄZrwh:s-C H4ŽCH2 . Ž .xŽ . 4
5
3 3 2 2
1
2
6
. The H NMR spectrum of this compound shows
Present address: Centro de Qu ´ı mica Estrutural, Complexo I,
Instituto Superior T e´ cnico, 1096 Lisboa Codex, Portugal.
fluxional behaviour due to sulphur inversion of the
0
022-328Xr98r$19.00 q 1998 Elsevier Science S.A. All rights reserved.

1
34
P.T. Gomes et al.rJournal of Organometallic Chemistry 551 (1998) 133–138
SMe group. Thus, at room temperature a broad reso-
order of magnitude of other ansa-bridged h-cyclo-
2
nance is observed at d 2.59, and this sharpens on
cooling. At y308C, a sharp peak is obtained which
pentadienyl-amido w2,3x or wZrŽh-C H5.R x w19,20x
5
3
based systems.
1
integrates for 6 protons. The H NMR spectrum shows
In conclusion, the new compounds and reactions are
shown in the Scheme 2.
the molecule has C symmetry and the structure pro-
s
posed for 6 is shown in Scheme 2, i.e., the SMe ligand
2
is coordinated to the Zr atom lying in between the two
Cl ligands. The reaction of 3 with ZrCl in CH Cl led
3. Experimental
4
2
2
1
to N SiMe3
ÄZrwh:s-C H4ŽCH2 .3 Ž .xCl24 7. The H NMR
5
spectrum of 7 reveals again a C symmetry compatible
All manipulations and reactions were carried out
s
with a monomeric structure, which is further confirmed
by the MS data. Attempts to force the elimination of
under an atmosphere of dinitrogen
or water using standard Schlenk vessel and vacuum-line
techniques or in a dry-box. Solvents were pre-dried over
Ž
-10 ppm oxygen
.
SiMe Cl either from 6 or 7 were unsuccessful. We have
3
˚
also explored the reaction of 3 with molybdenum pen-
tachloride in dichloromethane and found that extraction
of the reaction mixture with tetrahydrofuran gives a
red-brown microcrystalline paramagnetic compound
activated 4 A molecular sieves and then distilled under
an atmosphere of dinitrogen from potassium tetrahy-
drofuran , sodium toluene , sodium-potassium alloy
b.p. 40–608C
and diethyl etherx or
dichloromethane , and stored under
Ž
.
Ž
.
wlight petroleum
Ž
Ž
.
with stoichiometry corresponding to
C H4ŽCH2 .3
SiMe3 C H O Cl3 8. Treatment of 8
with trimethylphosphine causes substitution of the tetra-
hydrofuran ligand giving orange-brown
Mowh:s-
C H4ŽCH2 .3
SiMe3 PMe3
Ä
Mowh:s-
calcium hydride
.
N
Ž
.
x
Ž
.
8
4
dinitrogen. Deuteriated solvents for NMR samples were
5
4
stored in ampoules over activated molecular sieves
2
Ä
Ž
Ž
C D and w H x toluene
.
or dried using NarK alloy
6
6
8
2
N
Ž
.
x
Ž
.
Cl x 9.
w H x tetrahydrofuran
.
and calcium hydride CD Cl
Ž
.
2
5
3
8
2
A preliminary study shows that the zirconium amido
and transferred by vacuum distillation.
The NMR spectra were recorded on a Br u¨ ker AM-300
compound 6 in the presence of methylaluminoxane
4
1
13
Ž
AlrZr ratio ca. 1000
.
polymerises ethylene
Ž
9=10 g
w H, 300 MHz; C, 75.43 MHzx and referenced inter-
y1
y1
y1
1 13
of polyethylene
s
Ž
mol of Zr
to highly linear polyethylene
.
h
atm ; N s1.8
nally using residual H and C solvent resonances
relative to tetramethylsilane ds0 . Low resolution
t
y1
.
Ž
T s136.98C
.
Ž
.
m
w16,17x. In the same conditions, it oligomerises propy-
mass spectra were obtained on an AEI MS 302 mass
spectrometer, updated by a data-handling system sup-
plied by Mass Spectroscopy Services. Elemental analy-
ses were performed by the Analytical Laboratory in this
Department. The differential scanning calorimetry mea-
y1 y1
y1
lene
N s0.5 min
Ž
660 g of polypropylene
Ž
mol of Zr
to low molecular weight and highly
polydispersed products
.
h
atm
;
y1
.
t
Ž
M s2100; M rM s7.1 .
.
n
w
n
Although much less active than metallocene derivatives
w18x, this catalytic system has activities of the same
surements of polyethylene melting temperature, Tm
Ž .
Scheme 1. Synthesis of the ligand precursor 3. Reagents: Ži. ŽMe Si.SO CF and NEt3 in diethyl ether, 08C to room temperature, 4 h; Žii.
3
3
3
t
NaŽC H . in THF, y108C to room temperature, 12 h; Žiii. Li Bu in hexane, y78 to room temperature, 12 h, then Me SiCl, 5 h.
5
5
3

Table 1
Analytical and spectroscopic data of compounds 4–9
Compounda
Spectroscopic datab1
5
c
4
ÄTiwh :s-C H ŽCH . NŽSiMe .xCl 4
H r.t. : d 6.57 Žt, 2H, C H .; 6.19 Žt, 2H, C H .; 3.52 Žc, 2H, C H N.; 2.67 Žt, 2H, C H C H .; 2.08 Žm, 2H, C H C H C H .;
5
4
2
3
3
2
5
4
5
4
2
5
4
2
5
4
2
2
0
.46 Žs, 9H, SiŽC H . ..
3 3
C, 42.3 Ž42.5.; H, 6.0 Ž5.8.; N, 4.4 Ž4.5.; Cl, 22.3 Ž22.8.
5
1
c
5
ÄTiwh :s-C H ŽCH . Ž m-N.xCl4
H r.t. : d 6.85 Žq, 2H, C H .; 6.38 Žq, 2H, C H .; 6.08 Žq, 2H, C H .; 5.62 Žq, 2H, C H .; 3.71 Žm, 2H, H .; 3.44 Žm, 2H, H .;
5 4 5 4 5 4 5 4 g g
5
4
2
3
2
C, 47.4 Ž47.2.; H, 5.3 Ž5.0.; N, 6.7 Ž6.9.; Cl, 17.9 Ž17.4.
1
3
1
c
CÄ H4 r.t. : d 128.9 ŽC H ipso.; 116.6 ŽCH of C H .; 115.7 ŽCH of C H .; 115.3 ŽCH of C H .; 114.2 ŽCH of C H .;
9.1 ŽC .; 33.7ŽC .; 26.2 ŽC .
5
4
5
4
5
4
5
4
5
4
5
g f e
5
1
1
c
6
1
ÄZrwh :s-C H ŽCH . NŽSiMe .xŽSMe .Cl 4
H r.t. : d 6.66 Žt, 2H, C H .; 6.43 Žt, 2H, C H .; 2.83 Žm, 2H, C H N.; 2.71 Žt, 2H, C H C H .; 2.59 Žbr s, SŽC H . .;
5 4 5 4 2 5 4 2 3 2
5
4
2
3
3
2
2
.69 Žm, 2H, C H CH C H .; 0.90 Žs, 9H, SiŽC H . .
C, 36.6 Ž37.4.; H, 5.8 Ž6.0.; N, 3.3 Ž3.3.; Cl, 16.2 Ž17.0.
5 4 2 2 3 3
c
H y308C : d 6.66 Žt, 2H, C5H4.; 6.44 Žt, 2H, C5H4.; 2.74 Žm, 2H, C H N.; 2.64 Žt, 2H, C H C H .; 2.56 Žs, 6H, S ŽC H . .;
2
5
4
2
3 2
1
.60 Žm, 2H, C H CH C H .; 0.02 Žs, 9H, SiŽC H . .
5 4 2 2 3 3
d
1
H r.t. : d 6.31 Žt, 2H, C H .; 6.21 Žt, 2H, C H .; 2.75 Žm, 4H, C H NqC H C H .; 2.23 Žbr s, S ŽC H . .;
5
4
5
4
2
5
4
2
3 2
1
.69 Žs, 9H, SiŽC H ..
3
1 c
1
3
CÄ H4 r.t. : d 139.8 ŽC H ipso.; 121.5 ŽCH of C H .; 119.2 ŽCH of C H .; 45.2 ŽCH N.; 36.4 ŽC H CH .;
5
4
5
4
5
4
2
5
4
2
2
8.6 ŽC H CH CH .; 21.9 ŽSŽCH . .; 1.9 ŽSiŽCH . .
5 4 2 2 3 2 3 3
5
1
d
7
ÄZrwh :s-C H ŽCH . NSiŽMe .xCl 4
H r.t. : d 6.18 Žt, 2H, C H .; 5.58 Žt, 2H, C H .; 2.78 Žm, 2H, C H N.; 2.08 Žm, 2H, C H C H .;
5
4
2
3
3
2
5 4 5 4 2 5 4 2
1
.41 Žm, 2H, C H CH C H .; 0.43 Žs, 9H, SiŽCH . .
5 4 2 2 3 3
1 d
1
3
C, 36.6 Ž37.0.; H, 6.0 Ž6.0.; N, 3.5 Ž4.0.; Cl, 19.7 Ž19.95.
CÄ H4 r.t. : d 130.5 ŽC H ipso.; 116.2 ŽCH of C H .; 113.5 ŽCH of C H .; 52.0 ŽCH N.; 36.7 ŽC H CH .;
5 4 5 4 5 4 2 5 4 2
2
6.7 ŽC H CH CH .; 0.7 ŽSiŽCH . .
5 4 2 2 3 3
MS Žmrz.: 354 wMxq
5
8
ÄMowh :s-C H ŽCH . NŽSiMe .xŽOC H .Cl 4
Paramagnetic
Paramagnetic
5
4
2
3
3
4
8
3
C, 36.3 Ž38.5.; H, 5.2 Ž5.8.; N, 2.7 Ž3.0.; Cl, 23.6 Ž22.7.
5
9
ÄMowh :s-C H ŽCH . NŽSiMe .xŽPMe .Cl 4
5
4
2
3
3
3
3
C, 36.0 Ž35.7.; H, 5.9 Ž6.0.; N, 3.2 Ž3.0.; Cl, 22.9 Ž22.6.
a
b1
13
Analytical data given as: found Žcalculated. %. H NMR at 300 MHz, C at 75 MHz. Data given as: chemical shift Žd ., multiplicity Žsssinglet, dsdoublet, tstriplet, msmultiplet,
c
d
2
brsbroad., relative intensity and assignment. In CD Cl . In w H x benzene.
2
2
6

1
36
P.T. Gomes et al.rJournal of Organometallic Chemistry 551 (1998) 133–138
were performed on a Setaram TG-DSC 111
Ž
IST-CQE,
3.2. N,N-bis-trimethylsilyl-3-cyclopentadienylpropyl-
amine 2
Portugal , in the range 20–2008C, at a heating rate of
.
y1
5
8C min . The molecular weight analysis of
polypropylene was performed by gel permeation chro-
matography at 358C, on a Waters 150CV IST-CQE,
Portugal , using three Styragel columns HR 1, HR 3
and HR 4; 30=0.78 cm and THF at a flow rate of 1
Sodium cyclopentadienide
Ž
14.0 g; 158.9 mmol
was added dropwise to a solution of
N, N-bis-trimethylsilyl-3-bromopropylamine 38.5 g;
. The mixture was
.
in
Ž
3
THF 200 cm
Ž .
.
Ž
Ž
.
3
1
36.4 mmol in THF 350 cm
. Ž .
3
y1
cm min
.
stirred for 12 h and a white precipitate of NaBr sepa-
rated. The mixture was filtered and the solvent was
removed from the filtrate under reduced pressure. The
residue was extracted with pentane and filtered. The
filtrate was concentrated under vacuum to give a colour-
3
.1. N,N-bis-trimethylsilyl-3-bromopropylamine 1
3
Triethylamine
Ž
62.7 cm ; 449.9 mmol
.
and trimeth-
100.0 g; 449.9 mmol
were added dropwise to a suspension of 3-bromopro-
pylamine hydrobromide 32.8 g; 150.0 mmol in Et O
at 08C. The mixture was stirred for 2 h at this
temperature and for an additional 4 h at r.t. During the
reaction triethylammonium trifluoromethylsulfonate
formed as an oil at the bottom of the flask. The volatiles
ylsilyltriflouromethylsulfonate
Ž
.
less oil. Yield, 27.4 g, 75%.
Ž
.
1
2
H NMR
Ž
CDCl3
.
: d 6.36, 6.22, 6.06, 5.91
Ž
Hvinyl
c, 2H,
m, 2H,
mrz
3
Ž
300 cm
.
of C H5.; 2.86, 2.79
Ž
Hsat of C H ; 2.68
.
5
Ž
5
5
C H N
.
; 2.19
Ž . Ž
m, 2H, C H C H CH ; 1.50
2
5 5 2 2
C H CH C H
.
; 0.06
Ž
s, 18H, NSi
Ž
C H3. .. MS
Ž
.
:
5
5
2
2
3
q
2
83 wMx .
were evaporated under reduced pressure and the residue
3
was extracted with pentane
Ž
3=60 cm
.
and filtered.
3
.3. N,N-bis-trimethylsilyl-3-(trimethylsilylcyclopenta-
Evaporation of the solvent from the filtrate gave 1 as a
dienyl)-propylamine 3
colourless liquid. Yield, 38.2 g, 90%.
1
H NMR
Ž
CDCl3
; 1.93
C H3. .. MS
. Ž .
: d 3.34 t, 2H, BrC H CH ; 2.84
2 2
Ž
1
c, 2H, C H N
8H, Si
.
Ž
m, 2H, BrCH C H
.
; 0.14
Ž
s,
A solution of 2
Ž
27.4 g; 102.3 mmol
in THF 300
. Ž
2
2
2
q
3
Ž
Ž
mrz
.
: 267 wMx .
cm at y788C was treated with a 1.7 M solution of
.
3
Scheme 2. Reactions of the ligand precursor 3. Reagents: Ži. TiCl4 in toluene, y788C to room temperature, 12 h; Žii. TiCl in toluene, y78 to
4
6
08C, 12 h; Žiii. in toluene, 608C, 12 h, Živ. ZrCl ŽSMe . in dichloromethane, y108C to room temperature, 10 h; Žv. ZrCl in toluene, room
4
2
4
temperature, 2 days; Žvi. MoCl in dichloromethane, y788C to room temperature, 12 h, then THF; Žvii. PMe in THF, room temperature, 12 h.
5
3

P.T. Gomes et al.rJournal of Organometallic Chemistry 551 (1998) 133–138
137
3
t-butyl lithium
Ž
174.0 cm ; 102.3 mmol
.
in hexane in a
3.7. Synthesis of
{
Zr[h:s-C H (CH ) N(SiMe )]Cl }
2
7
5
4
2
3
3
dropwise manner. The solution was allowed to warm up
slowly to r.t. and stirred for a further 4 h. Then,
A solution of
Ä
wC H4ŽSiMe3
.
x
Ž
CH2 .3
15 cm
1.98 g; 8.5 mmol
N
ŽSiMe3.2
4
3
5
3
3
trimethylsilylchloride
Ž
18.5 cm ; 143.2 mmol
.
was
Ž
2.89 g; 8.5 mmol
.
in CH Cl
Ž
.
was added
in
at y308C. The mixture was allowed
2
2
added. After 8–10 h, the solution was filtered and the
solvent was evaporated from the filtrate. The residue
was extracted with pentane, filtered and the filtrate was
concentrated in vacuum to give a pale yellow oil. Yield,
dropwise to a suspension of ZrCl
Ž
.
4
3
CH Cl
Ž
100 cm
2
.
2
to react for 2 days at r.t. and a yellow solution formed.
The solvent was evaporated under reduced pressure and
the residue was stirred with pentane to give a yellow
powder. The suspension was cooled to y508C and
2
6.1 g, 75%.
Found
60.10 ; H 11.36
: d 6.46, 6.08
Ž
%
. Žcalc. for C H NSi3Ž
%
..: C 59.72
1
7
37
1
Ž
.
Ž
10.98
.
; N 4.28
Ž
4.12
.
.
H NMR
filtered. The residual solid was then extracted with
3
Ž
CDCl3
.
Ž
Hvinyl of C H4ŽSiMe3..; 3.28
Ž
.
5
diethylether 2=20 cm . The solution was filtered and
the filtrate was concentrated. On cooling to y808C a
pale-yellow precipitate formed. This was separated and
recrystallised from diethyl ether as a white solid. Yield,
0.91 g, 30%.
Ž
Hsat of C H4ŽSiMe3..; 2.79
Ž
m, 2H, C H N
;
.
; 2.33
1.62 m , 2H ,
s, 18, NSi
ŽC H3. .; 0.03
Ž
m,
5
2
2
H , C H
Ž
SiM e 3
.
C H 2
; 0.07
.
Ž
5
4
.
C H4ŽSiMe3
CH C H
.
Ž
5
2
2
3
Ž
s, 9H, C H
Ž
Si
Ž
C H3. ..
.
5
4
3
3
.8. Synthesis of
{
Mo[h:s-C H (CH ) N(SiMe )]-
3
.4. Synthesis of
{
Ti[h:s-C H (CH ) N(SiMe )]Cl }
2
4
5
4
2
3
3
5
4
2
3
3
(
OC H )Cl
}
8
4
8
3
A solution of 3
Ž
1.85 g; 5.50 mmol
.
in toluene was
0.60 cm ; 5.50
The compound
Ä
wC H4ŽSiMe3
.
x
Ž
CH2
.
3
N
Ž
SiMe3.2
4
3
3
5
added slowly to a solution of TiCl
Ž
3
4
Ž
.
Ž
.
3
.00 g; 8.83 mmol in CH Cl 15 cm was reacted
3
2
2
mmol
.
in toluene
Ž
50 cm
.
, at y788C. The mixture was
with a suspension of MoCl
Ž
2.41 g; 8.83 mmol in
.
5
warmed slowly to room temperature and allowed to
react for 12 h. The solvent was evaporated to dryness
and the orange residue was extracted with petroleum
3
CH Cl
Ž
200 cm
.
at y788C for 12 h. A red-brown
2
2
solid precipitated. This was separated and extracted
Ž .
with THF 3=20 cm and the extract was filtered. The
3
ether 40–608C . After filtration, the filtrate was con-
Ž .
filtrate was concentrated and pentane was added, induc-
ing the precipitation of 8 as a red-brown solid. Yield,
centrated and cooled to y308C giving orange crystals
of 4. Yield, 0.69 g, 40%.
2
.60 g, 60%.
.9. Synthesis of
{Mo[h:s-C H (CH ) N(SiMe )]-
5 4 2 3 3
3
.5. Synthesis of
{
Ti[h:s-C H (CH ) (m-N)]Cl}2
5
3
5
4
2 3
(
PMe )Cl
}
9
3
3
A toluene solution of 4
Ž
0.35 g; 1.12 mmol was
.
3
PMe3
Ž
0.45 cm 4.35 mmol
in THF and the mixture was
stirred for 12 h. The solvent was evaporated to dryness
and the residue was extracted with CH Cl 3=30
. The filtrate was concentrated and cooled to
.
was added to a solution
heated to 608C for 12 h. After filtration, the solvent was
slowly evaporated under vacuum and the concentrated
solution was cooled to y808C. The red-orange crystals
of 5 formed were separated by filtration and dried under
vacuum. Yield, 0.27 g, 60%.
of 8 1.78 g; 3.81 mmol
Ž .
Ž
2
2
3
cm
.
y808C. A dark orange solid formed which was sepa-
rated by filtration and washed with Et O. Addition of
2
3
.6. Synthesis of
{
Zr[h:s-C H (CH ) N(SiMe )]-
Et O to the mother liquor gave a second crop of 9.
Total yield, 1.43 g, 80%.
5
4
2
3
3
2
(
SMe )Cl
}
2
6
2
3
.10. Polymerisation of ethylene and propylene using
The compound wZrCl4ŽSMe2 .2 x w15x was prepared in
{
Zr[h:s-C H (CH ) N(SiMe )](SMe )Cl
}
2
r MAO
situ by treating ZrCl
Ž
2.33 g; 10.0 mmol
.
with SMe
5
4
2
3
3
2
4
2
3
60 cm3. at 08C. A
catalytic system
Ž
15.0 cm ; 20.4 mmol
.
in CH Cl
Ž
2
2
3
solution of 3
Ž
3.45 g; 10.0 mmol
.
in CH Cl
Ž
20 cm
.
2
2
Polymerisations were performed in a thermostated
was then added dropwise, at 08C, and the mixture was
allowed to react for 12 h. The solvent was evaporated to
3
and magnetically stirred 300 cm Fischer–Porter appar-
tus.
dryness and the residue was extracted with toluene and
3
filtered. The solution was concentrated
Ž
ca. 5 cm
.
and
3
pentane
pale off-white solid formed which was separated and
recrystallised from toluenerpentane 1:4 giving white
microcrystals of 6. Yield, 2.70 g, 65%.
Ž
10 cm
.
was added. On cooling to y808C a
3.10.1. Ethylene
MAO
box and toluene
thermostated to 258C and allowed to equilibrate with
Ž
1.762 g; 30.4 mmol
.
was weighed in a glove
3
Ž
.
Ž .
15 cm was added. The solution was

1
38
P.T. Gomes et al.rJournal of Organometallic Chemistry 551 (1998) 133–138
ethylene at 2 bar
Ž
relative pressure
of compound 6
.
. A colourless toluene
0.011 g; 0.026 mmol
References
3
solution
Ž
5 cm
.
Ž
.
was transferred into the reaction vessel and the pressure
maintained at 2 bar. During the first minutes the solu-
tion turned to pale yellow while the polyethylene started
precipitating. After 45 min the excess of ethylene was
vented and the contents of the reactor treated with 100
w x
1
D.M. Antonelli, M.L.H. Green, P. Mountford, J. Organomet.
Chem. 438 Ž1992. C4.
w2x J.C. Stevens, F.J. Timmers, R.D. Wilson, G.F. Schmidt, P.N.
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0
416815A2, 1991.
w3x J.M. Canich, G.G. Hlatky, H.W. Turner, Int. Pat. WO 92r00333,
992.
3
cm of a solution containing aliquots of 3 M HCl and
1
methanol, for 1 h. The polyethylene was filtered, washed
with acidified methanol and dried under reduced pres-
sure for 4 h, at 608C. No oligomer fraction was found
after evaporation of the toluene layer. Yield, 3.55 g of
polyethylene.
w4x A.K. Hughes, A. Meetsma, J.H. Teuben, Organometallics 12
Ž1993. 1936.
w5x P.J. Shapiro, W.D. Cotter, W.P. Schaefer, J.A. Labinger, J.E.
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Ž
1
994 169.
.
w7x J. Okuda, F.J. Schattenmann, S. Wocadlo, W. Massa,
Organometallics 14 Ž1995. 789.
3
.10.2. Propylene
Compound 6 0.013 g; 0.031 mmol
g; 37.3 mmol were weighed and the reaction started
using the same procedure as described above reaction
pressure: 2 bar; temperature: 258C . After 25 h the
w8x K.E. du Plooy, U. Moll, S. Wocadlo, W. Massa, J. Okuda,
Organometallics 14 Ž1995. 3129.
Ž
and MAO 2.168
. Ž
.
w9x D.W. Carpenetti, L. Kloppenburg, J.T. Kupec, J.L. Petersen,
Ž
Organometallics 15 1996 1572.
Ž
.
.
w10x P. Jutzi, U. Siemeling, J. Organomet. Chem. 500 Ž1995. 175.
w11x W.A. Herrmann, W. Baratta, M.J.A. Moraweitz, J. Organomet.
Chem. 497 Ž1995. C4.
reaction was stopped by venting the excess of propylene
and treating the reaction mixture with acidified
methanol. The toluene layer was separated from the
w12x W.A. Herrmann, M.J.A. Moraweitz, W. Baratta, J. Organomet.
Chem. 506 Ž1996. 357.
13 P.T. Gomes, M.L.H. Green, A.M. Martins, P. Mountford, J.
Organomet. Chem. 541 Ž1997. 121.
w14x S.J. Simpson, personal communication.
w15x E.C. Lund, T. Livinghouse, Organometallics 9 Ž1990. 2426.
w16x J. Brandrup, E.H. Immergut ŽEds.., Polymer Handbook, 3rd
edn., Wiley, 1989, Chap. V, p. 19.
aqueous one and dried over MgSO . After filtration, the
w
x
4
toluene was removed under reduced pressure giving
oligomeric polypropylene. Yield, 1.06 g.
Acknowledgements
w1
x
7 D.T. Mallin, M.D. Rausch, J.C.W. Chien, Polym. Bull. 20
Ž1988. 421.
w18x W. Kaminsky, R. Engehausen, K. Zoumis, Makromol. Chem.
We wish to thank the NATO and Junta Nacional de
Investiga c¸ a˜ o Cient ´ı fica e Tecnol o´ gica, Portugal, for fel-
1
93 Ž1992. 1643.
w19x C. Pellecchia, A. Proto, P. Longo, A. Zambelli, Makromol.
lowships
Ž
to PTG and AMM, respectively
.
and Dr. A.C.
IST-CQE, Portugal
for DSC and GPC measurements, respectively.
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Ž
.
w2
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