638
Schmid, Thewalt, Sedmera, Hanus, Mach:
Di-µ-chlorobis[chloro(η5-2,3,4,5-tetramethyl-1-phenylcyclopentadienyl)titanium(III)],
[(η5-C5Me4Ph)TiCl(µ-Cl)]2 (1)
Titanium tetrachloride (379 mg, 2 mmol) in 20 ml of toluene was reduced by butyllithium in hexanes
(1.3 ml, 2.08 mmol). The brown suspension was stirred for 20 min and then a clear solution of
freshly prepared Li(C5Me4Ph), made from C5HMe4Ph (400 mg, 2 mmol) and butyllithium (2.1 mmol),
in 50 ml of THF was added to the TiCl3 suspension. The colour turned to brown and did not change
after heating to 90 °C for 48 h. After cooling to room temperature, the solvent was removed, the
residue was washed with hexanes and finally recrystallized from toluene. The yield of brown crystals
of 1 was approximately 400 mg (63%). IR spectrum (KBr), cm–1: 2 955 (m), 2 926 (s), 2 863 (m),
1 601 (m), 1 507 (m), 1 479 (m), 1 445 (m), 1 381 (s), 1 076 (m), 1 024 (m), 762 (vs), 702 (vs), 451 (m),
432 (s). UV-VIS, nm (toluene, 23 °C): 340 (sh) < 410 >> 500 (sh) ≈ 580 (sh); (MTHF, 23 °C): 335 >>
480 (sh) ≈ 660. EPR (toluene or MTHF, 25 to –130 °C): no signal attributable to 1. Mass spectrum
(EI) (direct inlet, 200 °C), m/z (%): 630 (M+•, 2.4); 319 (10); 318 (10); 317 (45); 316 (20); 315
([M/2]+, 65); 314 (9); 313 (6); 282 (14); 281 (42); 280 ([M/2 – Cl]+, 44); 279 (100); 278 (26); 277
(45); 276 (13); 275 (26); 274 (6); 265 (7); 264 (7); 263 (13); 262 (9); 261 (6); 198 (9); 197 (30); 196 (8);
182 (14); 181 (18); 180 (5); 179 (8); 178 (8); 167 (18); 166 (20); 165 (34); 155 (10); 153 (7); 152
1
(10); 141 (10); 128 (8); 115 (13); 91 (27). H NMR spectrum: 2.069 s, 12 H (4 CH3); 2.161 s, 12 H
(4 CH3); 7.026 m, 10 H (2 C6H5). 13C NMR spectrum: 14.43 q; 15.72 q; 127.13 d; 128.64 d;
132.13 d; 136.37 s; 137.80 s; 140.83 s.
Di-µ-chlorobis[chloro(η5-pentabenzylcyclopentadienyl)titanium(III)], [(η5-C5Bn5)TiCl(µ-Cl)]2 (2)
A suspension of TiCl3 (2 mmol) in toluene (20 ml) was prepared as described above. A red solution
of pentabenzylcyclopentadienylpotassium, made from C5HBn5 (1.03 g, 2 mmol) and an excess of po-
tassium hydride in THF (30 ml), was added to the TiCl3 suspension at room temperature. After a day
at room temperature, the solution was cooled to 5 °C. Light blue crystals of [Li(THF)2(µ-Cl)2-
TiCl2(THF)2] (approximately 300 mg, 31%) crystallized out of the pale brown reaction mixture. The
identity of [Li(THF)2(µ-Cl)2TiCl2(THF)2] was confirmed by X-ray crystallography and lithium atom
absorption spectroscopy (calculated 1.43%, found 1.35% Li). The mother liquor was reduced to half
volume and put again to 5 °C. Compound 2 crystallized as very thin dark green plates. Further crys-
tals were obtained by repeated reducing the volume of the solution. The overall yield of green crys-
talline 2 was 30 mg (2.4%). Similar low yields were obtained in three reproduced experiments.
[(η5-C5Bn5)TiCl(µ-Cl)]2 (2): UV-VIS, nm (toluene, 23 °C): 350 (sh) < 415 >> 568; (MTHF, 23 °C):
310 > 460 (sh) > 640. EPR (toluene or MTHF, 23 to –196 °C): no signal attributable to 2. IR spec-
trum (KBr), cm–1: 3 104 (w), 3 084 (m), 3 063 (m), 3 028 (s), 2 930 (w), 2 918 (w), 1 603 (s), 1
584 (w), 1 495 (s), 1 451 (s), 1 182 (vw), 1 155 (vw), 1 076 (m), 1 030 (m), 795 (vw), 733 (vs), 696
(vs), 673 (vw), 588 (w), 480 (m), 461 (w), 444 (m). Mass spectrum (EI) (direct inlet, 300 °C), m/z
(%): 633 ([M/2]+, 6); 596 (8); 543 (10); 542 (7); 541 (13); 516 (6); 515 (7); 514 (16); 510 (5); 505
(5); 423 (6); 422 (5); 421 (10); 332 (5); 331 (10); 330 (15); 265 (6); 255 (9); 254 (9); 252 (8); 241
(11); 239 (5); 215 (5); 167 (8); 165 (6); 92 (9); 91 (100); 65 (6). NMR spectra were not measured
because of negligible solubility of 2 in C6D6.
X-Ray Crystallography
A brown prismatic crystal of 1 and a green thin plate crystal of 2 were mounted into Lindemann
glass capillaries in a glovebox containing purified nitrogen. Intensities were collected on a Philips
PW1100 four-circle diffractometer (sealed tube, graphite monochromator, Mo anode, λ = 0.71069 Å)
at room temperature. The structures of 1 and 2 were solved by iterative symbolic addition (ISA,
Collect. Czech. Chem. Commun. (Vol. 63) (1998)