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D. Bau et al. / Inorganica Chimica Acta 358 (2005) 36–40
39
98% (Aldrich), hexafluoroacetylacetone (Aldrich),
2,2,6,6-tetramethyl-3,5-heptanedione 98%, ethyltrichlo-
roacetate (Fluka), [HNMe2Ph]B(C6F5)4 (Montell) and
ethyl aluminum sesquichloride EASC (Albermarle) were
used as received. Acetylacetone was distilled before use,
1-hexene (Aldrich) was fractionally distilled on CaH2
and kept on molecular sieves (NaA zeolites, 8–12 mesh).
Complexes (acac)2ZrCl2, (acac)3ZrCl and (thd)3ZrCl
were synthesized according to methods reported in refer-
ence [16] and [17], respectively. Tl(hfac) was prepared
from TlOEt and hexafluoroacetylone analogously to
the synthesis of Tl(thd) reported below. Microanalyses
were carried out at Istituto di Chimica Inorganica e delle
Superfici, CNR, Padova. The 1H and 13C NMR spectra
were obtained as CDCl3 solutions on a Bruker AMX-
300 spectrometer operating at 300 and 75.48 MHz
respectively. The assignments of the proton and carbon
resonances were performed by standard chemical shift.
The determination of the average molecular weight of
the polymer was carried out on a Hubbehold viscometer
in toluene solutions at 55 ꢁC.
under stirring. The precipitation of TlCl as a white solid
occurred immediately. After stirring overnight, the mix-
ture was filtered and the filtrate evaporated to dryness
under vacuum. The white residue was washed with a
small amount of Et2O and dried under vacuum. Yield:
1.019 g, 68%. Elemental Anal. Calc. for C10H2Cl2O4Zr
requires C, 20.84; H, 0.17. Found: C, 20.23; the H per-
centage has not been determined because the signal is
covered by the noise of the instrument. 1H NMR
(CDCl3, d, ppm): 6.584 (CH). 13C (CDCl3, d, ppm):
95.10 (CH).
4.5. (hfac)3ZrCl (4)
Solid ZrCl4 (0.47 g, 2 mmol) was slowly added to a
solution of Tl(hfac) (2.530 g, 6.1 mmol) in Et2O (10
ml) under stirring. The precipitation of TlCl as a white
solid occurred immediately. After stirring for 2 h, the
mixture was filtered and the filtrate evaporated to dry-
ness under vacuum. The white residue was washed with
a small amount of Et2O and dried under vacuum. Yield:
1.030 g, 68%. Elemental Anal. Calc. for C15H3ClO6Zr
requires C, 24.09; H, 0.13. Found: C, 24.15; the H per-
centage has not been determined because the signal is
covered by the noise of the instrument. 1H NMR
(CDCl3, d, ppm): 6.582 (CH). 13C (CDCl3, d, ppm):
95.13 (CH).
4.2. Polymerization of 1-hexene
In a three-neck round bottom flask, 1-hexene (20.19
g), EASC (4 · 10ꢀ4mol) and a solution of the complex
(5 · 10ꢀ2 mmol) and co-catalyst in toluene (200 ml) were
introduced. The reaction was carried out at room tem-
perature for 1 h at 1.003 bar.
4.6. (thd)2ZrCl2 (5)
After adding MeOH (1 or 2 ml) at the end of the reac-
tion, the reaction solution was evaporated under re-
duced pressure and the polymer was dried at 60–70 ꢁC
under vacuum. The polymer (0.5 g) was dissolved in tol-
uene (50–60 ml) and the solution washed three times
with a solution of MeOH–HCl 1:1 (3 · 50 ml). The addi-
tion of a MeOH–acetone solution 1:1 (50 ml) and shak-
ing vigorously caused the coagulation of the polymer
which was separated and dried at 90 ꢁC for 3 h under
vacuum.
Solid ZrCl4 (0.443 g, 1.9 mmol) was slowly added to a
solution of Tl(thd) (0.150 g, 3.8 mmol) in Et2O (10 ml)
under stirring. The precipitation of TlCl as a white solid
occurred immediately. After stirring for one night, the
mixture was filtered and the filtrate evaporated to dry-
ness under vacuum. The white residue was washed with
a small amount of Et2O and dried under vacuum. Yield:
0.760, 76%. Elemental Anal. Calc. for C22H38Cl2O4Zr
requires C, 52.29; H, 7.47. Found: C, 52,35; H, 7.49%.
1H NMR (CDCl3, d, ppm): 1.166 (CH3), 5.992 (CH).
13C (CDCl3, d, ppm): 27.9 (CH3), 94.0 (CH).
4.3. Tl(thd)
To a solution of 2,2,6,6-tetramethyl-3,5-heptanedione
(2.947, 15.7 mmol) in n-pentane (10 ml) TlOEt (3.698 g,
14.5 mmol) was added. After stirring overnight, the
solution was evaporated to dryness under vacuum
obtaining Tl(thd) as a white solid in quantitative yield
(5.62 g). Elemental Anal. Calc. for C11H19O2Tl requires
C, 34.06; H, 4.10. Found: C, 34.18; H, 4.12%. 1H NMR
(CDCl3, d, ppm): 1.130 (CH3), 5.554 (CH). 13C (CDCl3,
d, ppm): 28.70 (CH3), 91.32 (CH).
Acknowledgment
We thank Mrs. Anna Rosa Moresco for carrying out
the microanalyses.
References
[1] V.C. Gibson, S.K. Spitzmesser, Chem. Rev. 103 (2003) 283.
[2] P. Mehrkhodavandi, R.S. Schrock, L.L. Pryor, Organometallics
22 (2003) 4569.
4.4. (hfac)2ZrCl2 (3)
[3] F. Benetollo, G. Carta, G. Cavinato, L. Crociani, G. Paolucci,
G. Rossetto, F. Veronese, P. Zanella, Organometallics 22 (2003)
3985.
Solid ZrCl4 (0.620 g, 2.6 mmol) was slowly added to a
solution of Tl(hfac) (2.14 g, 5.2 mmol) in Et2O (10 ml)