304 Organometallics, Vol. 18, No. 3, 1999
J ewson et al.
any unreacted lithium reagent; yield 230 mg (56%) of blue
crystals. H NMR (C6D6): -4.35 (27H), 16.28 (9H), 57.14 (3H)
was added an excess of H2, and the ampule was heated
overnight to 60 °C. The solution was filtered to remove Co
metal and the solvent removed in vacuo. The residue was
recrystallized from toluene to yield blue crystals; yield 250 mg
(59%). 1H NMR (C6D6): -2.56 (27H), 19.24 (9H), 61.53 (3H)
ppm. IR (KBr): 2962 (s), 2930 (s), 2904 (s), 2882 (s), 2541 (m),
Co-H 1669 (s), 1539 (m), 1471 (m), 1431 (m), 1363 (m), 1247
(w), 1161 (s) 1065 (m), 1030 (m), 986 (m), 970 (w), 862 (w),
774 (m), 728 (w), 646 (m), 527 (m), 490 (w) cm-1. UV-vis
(THF): 594 (ꢀ ) 452 M-1 cm-1), 630 (ꢀ ) 635 M-1 cm-1), 668
(ꢀ ) 582 M-1 cm-1), 982 (ꢀ ) 82 M-1 cm-1), 1456 (ꢀ ) 111 M-1
cm-1) nm. Mp: 237-240 °C. µeff ) 4.9(1)µB (295 K). Anal. Calc′d
for C24H41BCoN6: C, 59.63; H, 8.49; N, 17.39. Found: C, 59.75;
H, 8.66; N, 17.13. MS (m/e): 482 (64%), 380 (28%), 345 (29%),
288 (33%), 203 (22%), 160 (12%), 123 (100%), 91 (40%), 69
(48%).
1
ppm. IR (KBr): 2955 (s), 2928 (s), 2865 (m), 2560 (m), 1539
(m), 1471 (w), 1431 (m), 1351 (m), 1242 (m), 1187 (sm) 1067
(m), 1020 (w), 784 (m), 650 (m), 511 (w) cm-1. UV-vis (THF):
580 (ꢀ ) 235 M-1 cm-1), 614 (ꢀ ) 293 M-1 cm-1), 685 (ꢀ ) 499
M-1 cm-1), 1004 (ꢀ ) 25 M-1 cm-1), 1515 (ꢀ ) 70 M-1 cm-1
)
nm. Mp: 284-286 °C. µeff ) 4.3(1) µB (295 K). Anal. Calcd for
25H43BCoN6: C, 61.06; H, 8.61; N, 16.44. Found: C, 59.75;
C
H, 8.66; N, 16.31. MS (m/e): 482 (100%), 368 (41%), 256 (21%),
236 (14%), 185 (94%).
Meth yl(h ydr idotr is(3-ter t-bu tylpyr azolyl)bor ato)cobalt-
(II), Tpt-Bu Co(CH3) (1b). To a solution of 525 mg of Tpt-BuCo(I)
(0.926 mmol) in THF was added 0.46 mL of a 3.0 M solution
of MeLi in THF (1.5 equiv) at -10 °C. The mixture was stirred
for 7 h at -10 °C. The solution was brought into the drybox
and filtered. The solvent was removed in vacuo. The residue
was recrystallized from toluene after filtering the solution
through a silica gel plug to remove any unreacted lithium
reagent; yield 253 mg (60%). 1H NMR (C6D6): -5.02 (27H),
53.39 (3H), 57.17 (3H) ppm. IR (KBr): 2955 (s), 2922 (s), 2889
(m), 2500 (m), 1502 (m), 1461 (w), 1362 (m), 1258 (m), 1196
Deu ter ido(h ydr idotr is(3-ter t-bu tyl-5-m eth ylpyr azolyl)-
bor a to)coba lt(II), Tp t-Bu ,MeCo(D) (4-d ). A solution of 200
mg of Tpt-Bu,MeCo(N2) (0.392 mmol) in toluene-d8 in an ampule
was freeze-pump-thawed five times. To the solution was
added an excess of D2, and the ampule was heated overnight
at 60 °C. The solution was filtered and the solvent removed
in vacuo. The residue was recrystallized from toluene; yield
(s) 1089 (m), 1055 (s), 782 (s), 737 (s), 599 (m), 495 (m) cm-1
UV-vis (THF): 577 (ꢀ ) 277 M-1 cm-1), 611 (ꢀ ) 374 M-1
cm-1), 688 (ꢀ ) 839 M-1 cm-1) nm. Mp: 218-220 °C. µeff
.
1
110 mg (58%) of blue crystals. H NMR (C6D6): -2.59 (27H),
)
19.25 (9H), 61.57 (3H) ppm. IR (KBr): 2958 (s), 2930 (w), 2905
(w), 2863 (w), 2541 (w), 1539 (m), 1465 (m), 1430 (w), 1373
(m), Co-D 1201 (w), 1182 (s) 1084 (s), 1030 (w), 784 (m), 728
(w), 646 (w) cm-1. UV-vis (THF): 593 (ꢀ ) 815 M-1 cm-1),
632 (ꢀ ) 1155 M-1 cm-1), 668 (ꢀ ) 1080 M-1 cm-1), 999 (ꢀ )
119 M-1 cm-1), 1472 (ꢀ ) 206 M-1 cm-1) nm. Mp: 238-241
°C. MS (m/e): 482 (35%), 380 (14%), 345 (30%), 288 (26%), 123
(100%), 83 (16%).
4.9(1) µB (295 K). Anal. Calcd for C22H37BCoN6: C, 58.04; H,
8.19; N, 18.45. Found: C, 57.92; H, 8.18; N, 18.76. MS (m/e):
440 (100%), 260 (12%), 212 (12%), 109 (19%).
Author: Is the value of 2955 in the IR data above correct?
Eth yl(h yd r id otr is(3-ter t-bu tyl-5-m eth ylp yr a zolyl)bo-
r a to)coba lt(II), Tp t-Bu ,MeCo(CH2CH3) (2). To a solution of
700 mg of Tpt-Bu,MeCo(I) (1.15 mmol) in THF was added 0.86
mL of a 2.0 M solution of CH3CH2Li in THF (1.5 equiv) at -10
°C, and the reaction mixture was stirred for 7 h at -10 °C.
The solution was brought into the drybox and filtered, and
the solvent was removed in vacuo. The residue was recrystal-
lized from toluene after filtering the solution through a silica
gel plug to remove any unreacted lithium reagent; yield 325
mg (55%) of blue crystals. 1H NMR (C6D6): -6.62 (27H), 16.61
(9H), 53.78 (3H) ppm. IR (KBr): 2955 (s), 2928 (s), 2865 (m),
2560 (m), 1539 (m), 1471 (w), 1431 (m), 1351 (m), 1242 (m),
Eth ylen e(h yd r id otr is(3-ter t-bu tyl-5-m eth ylp yr a zolyl)-
bor a to)coba lt(I), Tp t-Bu ,MeCo(C2H4) (5). To a stirred solution
of 530 mg of Tpt-Bu,MeCo(N2) (1.13 mmol) in pentane in an
ampule was added an excess of ethylene. A color change from
brown to blue-green occurred immediately. The solution was
filtered and concentrated for recrystallization; yield 530 mg
1
(100%). H NMR (C6D6): -9.07 (27H), 14.18 (9H), 32.13 (3H),
146.50 (4H) ppm. IR (KBr): 2955 (s), 2925 (m), 2864 (m), 1544
(m), 1468 (w), 1425 (m), 1360 (m), 1191 (s), 1066 (m), 1026
(w), 781 (vs), 647 (m) cm-1. UV-vis (THF): 660 (ꢀ ) 313 M-1
1187 (sm) 1067 (m), 1020 (w), 784 (m), 650 (m), 511 (w) cm-1
.
cm-1), 1237 (ꢀ ) 288 M-1 cm-1) nm. Mp: 202-204 °C. µeff
)
UV-vis (THF): 581 (ꢀ ) 220 M-1 cm-1), 617 (ꢀ ) 275 M-1
cm-1), 688 (ꢀ ) 510 M-1 cm-1), 1023 (ꢀ ) 24 M-1 cm-1), 1526
(ꢀ ) 52 M-1 cm-1) nm. Mp: 260-261 °C. µeff ) 4.4(1) µB (295
K). MS (m/e): 482 (100%), 368 (42%), 256 (21%), 236 (15%),
185 (94%).
3.8(1) µB (295 K). Anal. Calcd for C26H44BCoN6: C, 61.06; H,
8.61; N, 16.44. Found: C, 59.75; H, 8.66; N, 16.31. MS (m/e):
482 (100%), 481 (41%), 138 (21%), 123 (94%).
P r op en e(h yd r id otr is(3-ter t-bu tyl-5-m eth ylp yr a zolyl)-
bor a to)coba lt(I), Tp t-Bu ,MeCo(C3H6) (6). An NMR tube was
charged with 20 mg of Tpt-Bu,MeCo(N2) (0.039 mmol) in toluene-
d8; to this was added an excess of propylene. A color change
from brown to green occurred immediately. 1H NMR (C7D8):
-142.26 (1H), -117.48 (1H), -20.36 (27H), 15.24 (9H), 24.70
(3H), 24.97 (3H), 110.72 (1H) ppm. UV-vis (pentane): 618 (ꢀ
) 219 M-1 cm-1), 659 (ꢀ ) 236 M-1 cm-1), 818 (ꢀ ) 158 M-1
cm-1), 961 (ꢀ ) 158 M-1 cm-1), 1250 (ꢀ ) 197 M-1 cm-1) nm.
Due to the extreme sensitivity of this complex, further
characterization was not attempted.
Cr ysta l Str u ctu r e Deter m in a tion s. Crystal, data collec-
tion, and refinement parameters are given in Table 4. Single
crystals of 1b, 4, and 5 were sealed in glass capillaries under
N2. The photographic data and the crystal symmetry indicated
an orthorhombic crystal system for 1b and a monoclinic crystal
system for 4 and 5. The systematic absences in the diffraction
data were consistent with the space groups Pna21 and Pnma
for 1b and were uniquely consistent with the reported space
groups for 4 and 5. Although the molecule of 1b possessed a
mirror plane, it was not aligned perpendicular to the z axis,
as would be required for the centrosymmetric option. The
structures were solved using direct methods, completed by
subsequent difference Fourier syntheses, and refined by full-
matrix least-squares procedures. A molecule of toluene (solvent
n -Bu t yl(h yd r id ot r is(3-ter t-b u t yl-5-m et h ylp yr a zolyl)-
bor a to)coba lt(II), Tpt-Bu ,MeCo((CH2)3CH3) (3). To a solution
of 500 mg of Tpt-Bu,MeCo(I) (0.821 mmol) in THF was added
0.493 mL of a 2.5 M solution of n-BuLi in THF (1.5 equiv) at
-10 °C, and the reaction mixture was stirred for 7 h at -10
°C. The solution was brought into the drybox and filtered. The
solvent was removed in vacuo. The residue was recrystallized
from toluene after filtering the solution through a silica gel
plug to remove any unreacted lithium reagent; yield 270 mg
(61%) of blue crystals. 1H NMR (C6D6): -6.51 (27H), 13.99 (3H),
16.56 (9H), 18.47 (2H), 53.87 (3H) ppm. IR (KBr): 2959 (s),
2928 (s), 2865 (s), 2552 (m), 1542 (m), 1463 (w), 1431 (m), 1361
(m), 1196 (s) 1066 (m), 1025 (m), 985 (m), 771 (m), 645 (m),
555 (w) cm-1. UV-vis (THF): 582 (ꢀ ) 214 M-1 cm-1), 620
(ꢀ ) 265 M-1 cm-1), 692 (ꢀ ) 553 M-1 cm-1), 711 (ꢀ ) 556 M-1
cm-1), 1041 (ꢀ ) 22 M-1 cm-1), 1546 (ꢀ ) 60 M-1 cm-1) nm.
Mp.: 185-190 °C. µeff ) 4.7(1) µB (295 K). Anal. Calcd for
C
28H49BCoN6: C, 62.34; H, 9.09; N, 15.58. Found: C, 62.79;
H, 9.39; N, 15.05. MS (m/e): 482 (100%), 344 (15%), 293 (45%),
288 (12%), 123 (23%), 41 (14%), 28 (46%).
Hyd r id o(h yd r id otr is(3-ter t-bu tyl-5-m eth ylp yr a zolyl)-
bor a to)coba lt(II), Tp t-Bu ,MeCo(H) (4). A solution of 450 mg
of Tpt-Bu,MeCo(N2) (0.884 mmol) in 25 mL of toluene in an
ampule was freeze-pump-thawed five times. To the solution