D. Cauzzi et al. / Journal of Organometallic Chemistry 663 (2002) 256Á
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257
2. Experimental
2.4. Preparation of Cp2TiR2
Cp2TiCl2 (3 g, 12 mmol) was dissolved in 80 ml of
THF. The dark red solution was cooled to 0 8C and
added of 9.2 g (ca. 40% molar excess) of RMgCl in 60 ml
of THF. The solution was allowed to reach room
temperature (r.t.) and stirred. The colour changed to
2.1. Methods and reagents
The solvents were reagent grade and were distilled
and dried using standard techniques. The reactions were
performed under nitrogen using Schlenk glassware and a
standard vacuum line. FTIR spectra were registered
using a Nicolet 5PC or Nexus spectrometers. H-, 13C-,
29Si-, 119Sn- and 19F-NMR were recorded on AC100,
AC300 and CXP200 Bruker instruments. CHN elemen-
orangeÁyellow while a white precipitate formed. The
/
completion of the reaction was monitored by NMR
until the complete disappearance of the Cp2TiCl2 and
Cp2TiRCl singlets at 6.58 and 6.40 (few ml of the
solution were dried, the residue dissolved in 2 ml of
CDCl3 and then filtered with cotton directly into the
NMR tube, by using a Pasteur pipette). The THF was
then evaporated under vacuum and the solid extracted
with C6H14. The extracted solution was filtered on celite
and dried, giving a viscous deep yellow liquid. Yield:
70%.
Anal. Calc. for C30H56O6Si2Ti: C, 58.42; H, 9.15.
Found: C, 58.92; H, 9.27%.
1H-NMR (d, 100 MHz, CDCl3): 6.27 s (10H, Cp);
4.12 sep (6H, J 6 Hz, CH(CH3)3); 1.19 d (36H, J 6 Hz,
CH(CH3)3), 0.54 s (4H, CH2).
1
tal analyses were performed with a CarloÁErba EA 1108
/
automated analyzer. All reagents were pure commercial
products except [Cu(CH3CN)4]PF6 which was prepared
as reported in the literature [8].
2.2. Preparation of RMgCl (Rꢁ
/
(PriO)3SiCH2)
The procedure for the preparation of the Grignard is
the one reported in the literature [9]. (PriO)3SiCH2Cl
was prepared by alcoholysis of Cl3SiCH2Cl in PriOH.
When preparing Cp2TiClR (1), Mg was activated with
1,2-dichloroethane in order to avoid the introduction of
bromide or iodide anions which do cause halogen
scrambling in the final compounds, giving mixtures of
Cp2TiClR and Cp2TiXR (XꢁI, Br). The THF solution
of the Grignard was used freshly made and filtered
through a cannula.
2.5. Preparation of Cp2ZrR2
Cp2ZrCl2 (0.6 g, 2.05 mmol) was dissolved in 50 ml of
THF. The solution was cooled to 0 8C and added of
1.12 g (4 mmol) of RMgCl in 30 ml of THF. The
solution was allowed to reach r.t. and stirred for 7 h.
The THF was then evaporated under vacuum and the
solid extracted with 3/4 portions of C6H14. The extracted
solutions were filtered on celite and dried, giving a white
solid. Yield: 85%.
1H-NMR (d, 100 MHz, CDCl3): 6.3 s (10H, Cp); 4.18
sep (6H, J 6 Hz, CH(CH3)3); 1.18 d (36H, J 6 Hz,
CH(CH3)3), 0.11 s (4H, CH2).
/
2.3. Preparation of Cp2TiClR (1)
Cp2TiCl2 (5 g, 20 mmol) was dissolved in 100 ml of
THF. The dark red solution was cooled to 0 8C and
added of 6 g (ca. 5% excess on the 1:1 molar ratio) of
RMgCl in 25 ml of THF. The mixture was stirred for 4 h
Anal. Calc. for C30H56O6Si2Zr: C, 54.58; H, 8.55.
Found: C, 53.92; H, 8.75%.
and the colour changed to orangeÁyellow while a white
/
precipitate formed. The solvent was evaporated under
vacuum and the residue extracted and decanted four
times with 25 ml of C6H14. The extracted solution was
filtered on celite. The C6H14 was evaporated until a little
2.6. Preparation of SnR4
SnCl4 (10 g, 38.38 mmol) was mixed with 250 ml of
cool THF. A white precipitate of THF solvate formed
and slowly redissolved. The colourless solution was
cooled to 0 8C and added of 44.67 g of RMgCl (ca.
4% molar excess) in 250 ml of THF. The solution was
stirred at r.t. for 4 days during which a white precipitate
formed. The THF was evaporated under vacuum and
the solid extracted with 4/5 portions of C6H14. The
extracted solutions were filtered on celite and dried to
give a waxy white solid. Yield: 75%.
turbidity appeared and the vessel was kept at ꢂ20 8C
/
for 1 day. A crystalline solid formed and was isolated by
filtration. Yield: 91%.
M.p. (8C): 82.5, without decomposition.
IR (cmꢂ1, solid, KBr pellet): 3116w, 3094w, 2966s,
2927m, 2891m, 2876m, 1464w, 1448m, 1380s, 1367s,
1354m, 1175s, 1136s, 1120s, 1041vs, 1019vs, 920m,
903m, 864m, 846m, 821s, 779m, 750m.
1H-NMR (d, 300 MHz, CDCl3): 6.4 s (10H, Cp); 4.1
sep (3H, J 6 Hz, CH(CH3)3); 1.8 s (2H, CH2); 1.2 d
(18H, J 6 Hz, CH(CH3)3).
Anal. Calc. for C20H33ClO3SiTi: C, 55.49; H, 7.68.
Found: C, 54.99; H, 7.75%.
1H-NMR (d ppm, 300 MHz, CDCl3): 4.18 sep (12H,
J 6 Hz CH(CH3)2); 1.15 d (72H, J 6 Hz CH(CH3)2);
0.12
s
(8H,
satellites:
2J(1H119Sn) 37:8;
2J(1H117Sn) 39:3 Hz; CH2).