Organometallics
Article
Data for 2a are as follows. Mp: 140 °C. EI-MS (direct inlet, 70 eV,
130 °C): m/z (relative abundance) 373 (M+•; 16), 320 (20), 319 (50),
318 ([M − HC2Me2]+; 100), 317 (40), 316 (54), 315 (47), 313 (17),
182 (22), 181 ([Cp*Ti − 2 H]+; 32), 180 (33), 179 (17), 178 (26),
177 (15), 135 ([Cp*]+; 9), 119 (23), 105 (11), 91 (22), 79 (8), 77
(9), 55 (18), 53 (13). IR (KBr, cm−1): 2976 (s, sh), 2952 (s), 2901
(vs), 2858 (s), 2720 (vw), 1583 (vw), 1489 (m), 1434 (s, b), 1377
(vs), 1164 (vw), 1064 (w), 1023 (s), 803 (vw), 615 (w), 483 (w), 423
(s). EPR (toluene-d8, 23 °C): giso = 1.962, ΔH = 19 G; (toluene-d8,
−140 °C): g1 = 1.999, g2 = 1.982, g3 = 1.890, gav = 1.957. UV−vis
mmol) was evaporated in a vacuum overnight, and the residue was
dissolved in hexane. Crystallization by slow solvent distillation in a
refrigerator yielded ocher thin needle aggregates. Yield: 0.29 g, 67%.
Data for 2e are as follows. Mp: 125 °C. EI-MS (direct inlet, 70 eV,
120 °C): m/z (relative abundance) 432 (10), 431 (M+•; 20), 430 (9),
429 (13), 320 (15), 319 (60), 318 ([M − HC2MeSiMe3]+; 100), 317
(89), 316 (31), 315 (19), 182 (15), 181 ([Cp*Ti − 2 H]+; 19), 180
(16), 179 (11), 178 (19), 177 (10), 135 ([Cp*]+; 7), 119 (8), 112
([C2MeSiMe3]+; 4), 105 (6), 97 ([C2MeSiMe3 − Me]+; 17), 91 (8),
73 ([SiMe3]+; 80). IR (KBr, cm−1): 2952 (s), 2904 (vs), 2858 (m),
2718 (vw), 1613 (w), 1552 (w), 1491 (w), 1436 (m,b), 1376 (s), 1245
(s), 1063 (w), 1022 (m), 849 (vs), 836 (vs), 766 (m), 730 (w), 684
(m), 614 (w), 571 (w), 546 (w), 499 (vw), 455 (w), 436 (m). EPR
(toluene-d8, 23 °C): giso = 1.984, ΔH = 4.0 G; (toluene-d8, −140 °C):
g1 = 2.000, g2 = 1.984, g3 = 1.974, gav = 1.986. UV−vis (toluene-d8,
nm): 505 ≫ 685(sh). 1H NMR (toluene-d8): −0.4 (ν1/2 = 40 Hz, 9H,
SiMe3); 15.5 (ν1/2 = 8100 Hz, 30H, C5Me5). Anal. Calcd for
C26H43SiTi (431.60): C, 72.36; H, 10.04. Found: C, 72.41; H, 10.09.
Preparation of 3a. Compound 2a (0.16 g, 0.43 mmol) was
dissolved in THF (4 mL), and the solution was added to degassed
PbCl2 (0.060 g, 0.215 mmol). After stirring for 30 min a red solution
was decanted from a black powder of lead, and THF was evaporated.
The residue was dissolved in a minimum of hexane and crystallized by
slow solvent distillation in a refrigerator. A brownish-yellow mother
liquor was separated, and a bright red crystalline solid was rinsed with
condensing hexane vapor and dried in a vacuum. Yield: 0.14 g (79%).
Warning: compounds 3a−3e undergo photodecomposition when
exposed to sunlight; storing their solutions in the dark is
recommended.
1
(toluene-d8, nm): 340(sh) ≫ 465(sh) > 620. H NMR (toluene-d8):
−12.4 (ν1/2 = 1200 Hz, 3H); 12.3 (ν1/2 = 800 Hz, 3H); 17.7 (ν1/2
=
3000 Hz, 30H, C5Me5). Anal. Calcd for C24H37Ti (373.44): C, 77.19;
H, 9.99. Found: C, 77.15; H, 9.96.
Preparation of 2b. A solution of 1 in hexane (1.0 mmol in 4.0
mL) was poured onto degassed tolan (0.18 g, 1.01 mmol) to give a
brown solution. Attempts to crystallize the product were unsuccessful;
hence, the solution was evaporated in a vacuum, and a brown solid
residue was dissolved in toluene-d8 for investigation by spectral
methods. Yield of 2b higher than 74% is derived from the yield of its
chlorinated product 3b (see below).
1
Data for 2b are as follows. H NMR (toluene-d8): 3.7 (ν1/2 = 280
Hz, 4H); 7.4 (ν1/2 = 11 Hz, 1H); 7.6 (ν1/2 = 60 Hz, 2H); 8.0 (ν1/2
=
40 Hz, 2H); 10.1 (ν1/2 = 210 Hz, 1H); 16.4 (ν1/2 = 4400 Hz, 30H,
C5Me5). EPR (toluene-d8, 23 °C): giso = 1.972, ΔH = 7.0 G; (toluene-
d8, −140 °C): g1 = 2.001, g2 = 1.985, g3 = 1.964, gav = 1.983. UV−vis
(toluene-d8, nm): 360(sh) ≫ 500(sh) > 695.
Preparation of 2c. Mixing of 1 in hexane (1.0 mmol in 4.0 mL)
with degassed phenylpropyne (0.116 g, 1.0 mmol) afforded a greenish-
brown solution. Crystallization by slow solvent distillation in a
refrigerator yielded aggregates of thin-plate pale brown crystals. These
were washed with condensing hexane vapor and dried in a vacuum.
Yield: 0.24 g (56%).
Data for 2c are as follows. Mp: 82 °C. EI-MS (direct inlet, 70 eV,
110 °C): m/z (relative abundance) 436 (9), 435 (M+•; 18), 320 (17),
319 (48), 318 ([M − HC2MePh]+; 100), 317 (87), 316 (30), 315
(17), 182 (12), 181 ([Cp*Ti − 2 H]+; 14), 180 (13), 179 (11), 178
(18), 177 (10), 135 ([Cp*]+; 7), 119 (13), 117 (18), 115 (14), 105
(10). IR (KBr, cm−1): 3075 (vw), 3052 (w), 2947 (s), 2930 (s, sh),
2900 (vs), 2855 (s), 2720 (vw), 1590 (m), 1567 (w), 1486 (s), 1437
(s, b), 1376 (s), 1076 (w), 1023 (m), 844 (w), 794 (m), 742 (m), 700
(s), 671 (w), 576 (w), 435 (m). EPR (toluene-d8, 23 °C): giso = 1.972,
ΔH = 7.0 G; (toluene-d8, −140 °C): g1 = 2.000, g2 = 1.984, g3 = 1.962,
gav = 1.982. UV−vis (toluene-d8, nm): 310(sh) ≫ 495(sh) > 660(sh).
1H NMR (toluene-d8): −20.6 (ν1/2 = 2100 Hz); 7.5 (ν1/2 = 60 Hz);
8.1 (ν1/2 = 50 Hz); 9.7 (ν1/2 = 100 Hz); 17.3 (ν1/2 = 2500 Hz, 30H,
C5Me5). Anal. Calcd for C29H39Ti (435.51): C, 79.98; H, 9.03. Found:
C, 80.03; H, 9.06.
Data for 3a are as follows. Mp: 158 °C. EI-MS (direct inlet, 70 eV,
150 °C): m/z (relative abundance) 410 (9), 408 (M+•; 13), 355 (12),
354 ([M − C2Me2]+; 10), 318 ([M − C2Me2 − HCl]+; 10), 220 (37),
219 (51), 218 ([M − C2Me2 − Cp*H]+; 100), 217 (86), 216 (30),
215 (20), 213 (27), 181 ([Cp*Ti − 2 H]+; 8), 135 ([Cp*]+; 36), 119
(40), 105 (26), 91 (21), 79 (12), 77 (16). IR (KBr, cm−1): 2985 (m),
2953 (m), 2898 (vs), 2845 (s), 2717 (vw), 1621 (vw), 1491 (m), 1449
(m), 1433 (s), 1375 (vs), 1165 (vw), 1102 (w), 1065 (w), 1022 (s),
957 (vw), 809 (w), 614 (vw), 596 (w), 477 (vw), 439 (vw), 403 (m).
Anal. Calcd for C24H37ClTi (408.89): C, 70.50; H, 9.12. Found: C,
70.53; H, 9.16. 1H and 13C{1H} NMR spectra resolved the presence of
two atropisomers, 3a(a) (60%) and 3a(b) (40%).
Data for 3a(a): 1H NMR (toluene-d8): 1.62−1.69 (m, 3H,
CHMe); 1.74−1.78 partially overlapped (m, 3H, TiC(Me)); 1.78 (s,
30H, C5Me5); 3.62−3.73 (m, 1H, CHMe). 13C{1H} NMR (toluene-
d8): 12.97 (C5Me5); 16.49 (CHMe); 29.48 (TiC(Me)); 119.92
(CHMe), 124.72 (C5Me5); 200.31 (TiC(Me)).
Data for 3a(b): 1H NMR (toluene-d8): 1.50−1.57 (m, 3H,
CHMe); 1.81 (s, 30H, C5Me5); 5.28−5.38 (m, 1H, CHMe).
13C{1H} NMR (toluene-d8): 12.97 (C5Me5); 16.51 (CHMe); 21.34
(TiC(Me)); 123.35 (CHMe), 124.67 (C5Me5); 206.50
(TiC(Me)).
Preparation of 2d. A solution of 1 in hexane (1.0 mmol in 4.0
mL) was added to degassed t-BuCCMe (0.15 mL, 1.1 mmol) to
give a yellow-brown solution. Volatiles including an excessive alkyne
were evaporated under dynamic vacuum at 40 °C overnight. The
residue was repeatedly crystallized from hexane to give aggregates of
brown needle crystals. Yield: 0.35 g (85%).
Preparation of 3b. Solutions of crude compound 2b in hexane
and toluene-d8 (see above) were combined and evaporated in a
vacuum. The brown residue was dissolved in THF (4 mL), and the
solution was poured onto degassed PbCl2 (0.14 g, 0.5 mmol), turning
red within 20 min. The red solution was evaporated, and the residue
was repeatedly extracted with 15 mL of hexane. The combined extracts
were reduced to 5 mL, and the brown mother liquor was separated
from a finely crystalline red powder of 3b. This was rinsed with
condensing hexane vapor and dried. Yield: 0.39 g (74%).
Data for 2d are as follows. Mp: 110 °C. EI-MS (direct inlet, 70 eV,
110 °C): m/z (relative abundance) scan 12 416 (7), 415 (M+•; 16),
414 (11), 320 (33), 319 (87), 318 ([M − HC2MeBu]+; 100), 317
(95), 316 (60), 315 (42), 314 (13), 313 (18), 312 (8), 311 (9), 182
(19), 181 ([Cp*Ti − 2 H]+; 26), 180 (27), 179 (16), 178 (33), 177
(20), 176 (13), 135 ([Cp*]+; 6), 119 (14), 105 (13), 91 (13). IR
(KBr, cm−1): 2980 (m), 2949 (s), 2899 (vs), 2858 (s), 2720 (vw),
1490 (w), 1454 (m), 1434 (m), 1377 (s), 1356 (m), 1227 (w), 1201
(w), 1165 (vw), 1064 (w), 1021 (m), 801 (w), 752 (w), 719 (w), 648
Data for 3b are as follows. Mp: 155 °C. 1H NMR (toluene-d8): 1.86
(s, 30H, C5Me5); 4.64 (s, 1H, CHPh); 6.79−7.18 (m, 10H, Ph).
13C{1H} NMR (toluene-d8): 13.30 (C5Me5); 124.64, 124.97 (CH, Ph);
126.33 (C5Me5); 127.08 (CHPh); 128.19, 128.33, 128.62, 128.77
(CH, Ph); 204.75 (TiC). EI-MS (direct inlet, 70 eV, 150 °C): m/z
(relative abundance) 533 (9), 532 (M+•; 20), 497 ([M − Cl]+; 7), 396
([M − Cp*H]+; 10), 354 ([M − C2Ph2]+; 19), 320 (15), 319 (40),
318 ([M − C2Ph2 − HCl]+; 100), 317 (67), 316 (20), 315 (10), 182
(8), 181 ([Cp*Ti − 2 H]+; 11), 180 (15), 179 (15), 178 ([C2Ph2]+;
28), 135 ([Cp*]+; 10), 119 (15), 105 (13), 91 (13). IR (KBr, cm−1):
1
(vw), 437 (m). H NMR (toluene-d8): 18.4 (ν1/2 = 2100 Hz, 30H,
C5Me5); 1.7 (ν1/2 = 30 Hz, 9H, CMe3). EPR (toluene-d8, 22 °C): g =
1.968, ΔH = 9.0 G; (−140 °C): g1 = 2.000, g2 = 1.983, g3 = 1.964, gav =
1.982. UV−vis (toluene-d8, nm): 345(sh) ≫ 465 > 650. Anal. Calcd
for C27H43Ti (415.52): C, 78.05; H, 10.43. Found: C, 78.10; H, 10.49.
Preparation of 2e. A brown reaction mixture of 1 in hexane (1.0
mmol in 4.0 mL) and degassed (trimethylsilyl)propyne (0.20 mL, 1.3
3408
dx.doi.org/10.1021/om500296h | Organometallics 2014, 33, 3399−3413