1242 Organometallics, Vol. 18, No. 7, 1999
Lukens et al.
Cooling to -20 °C yielded purple-orange needles (1.52 g, 80%).
Mp: 180-186 °C. IR: 3062 (w), 2722 (w), 1247 (s), 1198 (w),
(M)+ m/z (calcd, found): 694 (100, 100), 695 (45, 68), 696 (23,
33), 697 (7, 12). Anal. Calcd for C22H42F2Si4U: C, 38.0; H, 6.09.
Found: C, 37.5; H, 6.26.
1167 (m), 1076 (s), 1057 (w), 1025 (m), 847 (s), 788 (s) cm-1
.
MS (M)+ m/z (calcd, found): 846 (100, 100), 847 (30, 31). Anal.
Calcd for C26H42I2U: C, 36.9; H, 5.00. Found: C, 36.9; H, 5.14.
(Note: the product often needed a second treatment with Me3-
SiI to completely metathesize all of the chlorides.)
Cp ′′2U(NMe2)2. Cp′′2UCl215 (4.00 g, 5.50 mmol) and LiNMe2
(0.57 g, 11 mmol) were suspended in 100 mL of tetrahydro-
furan. The solution immediately became warm and turned
dark yellow-green. After the mixture was stirred for 12 h, the
tetrahydrofuran was removed under reduced pressure. The
green solid residue was suspended in 90 mL of hexane, and
the solution was filtered. The volume of the filtrate was
reduced to ca. 10 mL. Cooling to -20 °C produced orange
blocks (2.82 g, 69%). Mp: 125-127 °C. IR: 3050 (w), 2767 (s),
1317 (w), 1245 (s), 1208 (m), 1141 (s), 1122 (w), 1079 (s), 1058
(m), 919 (s), 833 (s), 779 (s), 754 (s), 689 (m), 636 (m), 616 (w)
cm-1. MS (M)+ m/z (calcd, found): 744 (100, 100), 745 (50, 52),
746 (25, 26). Anal. Calcd for C26H54N2Si4U: C, 41.9; H, 7.30;
N, 3.76. Found: C, 41.9; H, 7.33; N, 3.29.
Cp ′′2UI2.15 Cp′′2UCl2 (1.5 g, 2.1 mmol) was dissolved in
15
50 mL of hexane, and Me3SiI (0.84 mL, 1.2 g, 6.2 mmol) was
added by syringe. The initially orange solution quickly turned
red. After the mixture was stirred for 10 h, the volatile
components were removed under reduced pressure, and the
dark red solid residue was dissolved in 75 mL of hexane. The
solution was filtered, and the volume of the filtrate was
reduced to ca. 45 mL. Cooling to -20 °C gave purple-brown
1
blocks (1.52 g, 81%). The H NMR spectrum agrees with that
reported previously.15 (Note: the product often needed a second
treatment with Me3SiI to completely metathesize all of the
chlorides.)
Cp q2U(OMe)2. Cpq2UCl2 (3.00 g, 4.52 mmol) and KOMe
(0.65 g, 9.3 mmol) were suspended in 50 mL of tetrahydrofu-
ran. After the mixture was stirred at 70 °C for 12 h, the
tetrahydrofuran was removed under reduced pressure, yielding
a viscous green oil, which slowly solidified under vacuum. The
green solid residue was suspended in 50 mL of hexane, and
the solution was filtered. The volume of the filtrate was
reduced to ca. 5 mL, and additional white solid precipitated.
After 12 h the solution was filtered and the volume was
reduced to ca. 2.5 mL. Cooling to -20 °C produced green blocks
(2.05 g, 69%). Mp: 86-88 °C. IR: 3067 (w), 2726 (w), 1297
(w), 1251 (s), 1201 (m), 1166 (m), 1115 (s), 1093 (s), 1055 (m),
1025 (m), 975 (w), 936 (m), 822 (s), 753 (s), 723 (w), 679 (m),
657 (m) cm-1. MS (M)+ m/z: 654. Anal. Calcd for C28H48O2U:
C, 51.4; H, 7.39. Found: C, 50.3; H, 7.25.
Cp q2UF 2. (a) Cpq2UMe2 (1.23 g, 2.00 mmol) was dissolved
in 30 mL of diethyl ether, and BF3‚OEt2 (0.51 mL, 0.59 g, 4.1
mmol) was added using a syringe. The solution immediately
became warm and turned green. After 12 h, the diethyl ether
was removed under reduced pressure, and the tube was heated
to 80 °C under vacuum for 1 h to remove MeBF2. The orange
solid residue was dissolved in 50 mL of hexane, and the
solution was filtered. The volume of the filtrate was reduced
to ca. 25 mL. Cooling to -20 °C produced orange-yellow
needles (1.00 g, 80%). Mp: 173-176 °C. IR: 3100 (w), 2730
(w), 1290 (w), 1255 (s), 1205 (m), 1165 (m), 1060 (m), 1035
(w), 925 (m), 825 (m), 820 (s), 785 (m), 725 (w), 685 (m), 665
(m), 510 (s), 480 (s), 430 (w), 355 (m), 245 (m) cm-1. MS (M)+
m/z: 630. Anal. Calcd for C26H42F2U: C, 49.5; H, 6.71. Found:
C, 49.5; H, 6.86.
15
Cp ′′2U(OMe)2. Cp′′2UCl2 (2.00 g, 2.57 mmol) and KOMe
(0.40 g, 5.6 mmol) were suspended in 50 mL of tetrahydrofu-
ran. The mixture was heated to 70 °C and was stirred for 12
h. The mixture was filtered, the tetrahydrofuran was removed
under reduced pressure, and the solid was heated to 60 °C
under vacuum for 1 h. The dark solid residue was suspended
in 50 mL of hexane and the suspension filtered. The volume
of the solution was reduced to ca. 10 mL, and a white solid
precipitated. After 12 h, the solution was filtered, and the
volume of the solution was reduced to ca. 2 mL. Cooling to
-20 °C produced dark purple blocks (1.65 g, 84%). Mp: 95-
99 °C. IR: 3043 (w), 2812 (m), 1316 (w), 1247 (s), 1212 (w),
1113 (s), 1086 (s), 1055 (m), 920 (s), 835 (s), 781 (m), 754 (s),
689 (w), 634 (s), 620 (w) cm-1. MS (M)+ m/z: 718. Anal. Calcd
for C24H48O2Si4U: C, 40.1; H, 6.73. Found: C, 39.7; H, 6.70.
(b) Cpq2U(OMe)2 (1.53 g, 2.34 mmol) was dissolved in 25 mL
of diethyl ether, and BF3‚OEt2 (0.60 mL, 0.70 g, 4.9 mmol) was
added using a syringe. The color of the solution immediately
changed from green to red. After the mixture was stirred for
6 h, the ether was removed under reduced pressure, and the
tube was heated to 70 °C under vacuum for 1 h. The red solid
residue was suspended in 50 mL of hexane, and the solution
was filtered. The volume of the filtrate was reduced to ca. 30
mL. Cooling to -20 °C gave yellow needles (1.1 g, 74%). The
1H NMR spectrum was identical with that of Cpq UF2 produced
2
by route a.
Cp q2UMe2. Cpq2UCl2 (1.00 g, 1.51 mmol) was dissolved in
50 mL of ether, and MeLi (4.2 mL, 0.72 M in diethyl ether,
3.0 mmol) was added by syringe. The solution immediately
turned orange and cloudy. After the mixture was stirred for 1
h, the ether was removed under reduced pressure. The dark
orange solid residue was suspended in 25 mL of hexane, and
the solution was filtered, giving a deep orange solution. The
volume of the solution was reduced to ca. 2 mL. Cooling to
-20 °C gave orange-brown blocks (0.73 g, 78%). Mp: 120-
125 °C. IR: 1250 (s), 1200 (m), 1165 (m), 1110 (s), 1055 (m),
1025 (m), 935 (m), 845 (m), 825 (s), 810 (m), 765 (s), 675 (m),
655 (m), 405 (m) cm-1. MS (M - CH3)+ m/z: 659. Anal. Calcd
for C28H48U: C, 54.0, H, 7.71. Found C, 53.7; H, 7.83.
[Cp ′′2UF 2]2. Cp′′2U(NMe2)2 (0.50 g, 0.67 mmol) was dis-
solved in 25 mL of diethyl ether, and BF3‚OEt2 (0.17 mL, 0.19
g, 1.3 mmol) was added using a syringe. The orange solution
turned bright green after 5 min. After the mixture was stirred
for 12 h, the volatile components were removed under reduced
pressure, and the reaction mixture was heated to 70 °C under
vacuum to remove Me2NBF2. The green solid residue was
dissolved in 40 mL of hexane, and the solution was filtered.
The volume of the solution was reduced to ca. 2 mL. Cooling
to -20 °C produced green blocks (0.34 g, 72%). Mp: 114-116
°C. IR: 3041 (m), 1318 (w), 1247 (s), 1204 (m), 1079 (s), 917
(s), 839 (s), 793 (s), 753 (s), 692 (m), 637 (s), 619 (w), 515 (s),
475 (s), 370 (s), 355 (s), 310 (s), 270 (m), 245 (w) cm-1. MS
15
Cp ′′2UMe2. Cp′′2UCl2 (2.00 g, 2.75 mmol) was dissolved
in 50 mL of diethyl ether and MeLi (10.6 mL, 0.52 M in diethyl
ether, 5.5 mmol) was added by syringe. The solution im-
mediately turned red-orange and cloudy. After the mixture was
stirred for 10 h, the solvent was removed under reduced
pressure. The orange solid residue was suspended in 50 mL
of hexane, and the solution was filtered. The volume of the
filtrate was reduced to ca. 3 mL. Cooling to -20 °C produced
red-orange crystals (1.45 g, 77%). Mp: 120-125 °C. IR: 1250
(s), 1200 (m), 1165 (m), 1110 (s), 1055 (m), 1025 (m), 935 (m),
845 (m), 825 (s), 810 (m), 765 (s), 675 (m), 655 (m), 405 (m)
cm-1. MS (M - CH3)+ m/z: 659. Anal. Calcd for C24H48Si4U:
C, 54.0; H, 7.71. Found: C, 53.7; H, 7.83.
Cp q2U(Me)Cl. Cpq2UCl2 (2.00 g, 3.01 mmol) was dissolved
in 50 mL of hexane. MeLi (5.80 mL, 0.52 M in ether, 3.0 mmol)
was added using a syringe. The solution immediately turned
a cloudy red-orange. After the mixture was stirred for 8 h, the
solution was filtered, and the volume of the solvent was
reduced to ca. 7 mL. Cooling to -20 °C produced red-orange
blocks (1.35 g, 70%). Mp: 128-132 °C. IR: 3091 (w), 2740 (w),
2720 (w), 1293 (w), 1248 (s), 1199 (m), 1166 (m), 1114 (m),
1056 (m), 1023 (m), 935 (m), 927 (m), 832 (s), 811 (w), 775 (s),
659 (w) cm-1. MS peaks at m/z 607, 627, and 662 are seen,
corresponding to Cpq2UMe, Cpq2UCl, and Cpq2UCl2, respec-