A R T I C L E S
Wooten et al.
as a white powder after drying under reduced pressure [69% yield
based on Pr(O3SCF3)3]. Pale X-ray-quality crystals were obtained
via vapor diffusion of dry pentane into a THF solution of 1-Pr: 1H
NMR (300 MHz, THF-d8) δ ) -11.36 (br s, 2H), 3.68 (br s, 2H),
7.76 (br-d, J ) 6.5 Hz, 2H), 8.34 (br-t, J ) 7.1 Hz, 2H,), 9.96 (br
s, 2H), 14.34 (br-d, J ) 5.1 Hz, 2H); 13C{1H} NMR (75 MHz,
THF-d8) δ ) 124.1, 124.4, 126.3, 128.2, 129.3, 133.4, 135.4, 144.0,
147.6, and 176.6 ppm.
4.2.2. Synthesis of Li3(THF)3(BINOLate)3Yb (1-Yb). The syn-
thesis of 1-Yb was accomplished using general procedure A. The
reagents were Li2(R-BINOLate) (0.721 g, 2.42 mmol), Yb(O3SCF3)3
(0.50 g, 0.806 mmol), and THF (60 mL). Compound 1-Yb (0.749
g) was isolated in 73% yield based on Yb(O3SCF3)3: 1H NMR (300
MHz, THF-d8) δ ) -13.44 (br s, 2H), -1.02 (br s, 2H), 2.95 (br
s, 2H), 8.31 (d, J ) 8.1 Hz, 2H,), 23.74 (br s, 2H), 88.59 (br s,
2H); 13C{1H} NMR (75 MHz, THF-d8) δ ) 56.6, 108.0, 110.4,
114.1, 116.5, 122.1, 124.0, 124.7, 140.6, and 178.3 ppm; IR (KBr)
ν ) 3048, 2956, 2873, 1615, 1591, 1558, 1502, 1464, 1425, 1341,
1278, 1249, 1143, 1071, 995, 957, 936, 860, 823, 746, 669, 576,
482 cm-1. Anal. Calcd for C72H60O9Li3Yb: C, 68.46; H, 4.79.
Found: C, 68.31; H, 4.88.36
4.3. General Procedure B: Crystallization of Li3(THF)4(BINO-
Late)3Ln(THF) (2-Ln) Complexes. Under a nitrogen atmosphere,
30 mg of Li3(THF)3(BINOLate)3Eu (1-Eu), Li3(THF)3(BIN-
OLate)3Pr (1-Pr), or Li3(THF)3(BINOLate)3La (1-La) was added
to a 4 mL vial and dissolved in 1.0 mL of anhydrous THF. The
vial was then placed inside of a 20 mL screw-capped vial that was
half-filled with dry pentane. After several days of pentane diffusion
at room temperature, pale X-ray-quality crystals of compounds
2-Eu, 2-Pr, or 2-La were obtained. These crystals were subjected
to X-ray diffraction studies. NMR spectra of 2-Eu, 2-Pr, and 2-La
in THF-d8 were identical to those of compounds 1-Eu, 1-Pr, and
1-La, respectively.11,15
4.3.1. Crystallization of Li3(py)5(BINOLate)3La(py)2 (3-La).
Li3(THF)3(BINOLate)3La (1-La, 30 mg) was added to a 4 mL vial
and dissolved in pyridine (1.0 mL). This vial was then placed within
a 20 mL screw-capped vial that was half-filled with dry pentane.
After several days of pentane diffusion at room temperature, pale
crystals formed that were suitable for X-ray structure determination:
1H NMR (500 MHz, THF-d8, 25 °C, TMS) δ ) 6.79 (m, 4H),
6.89 (m, 2H), 6.98 (d, J(H,H) ) 8.7 Hz, 2H), 7.22 (m, 7H), 7.58
(d, J(H,H) ) 8.8 Hz, 2H), 7.60 (d, J(H,H) ) 8.0 Hz, 2H), 7.65 (m,
3H), 8.52 (m, 7H) ppm; 13C{1H} NMR (125 MHz, THF-d8) δ )
119.1, 120.4, 124.4, 124.8, 126.8, 126.9, 128.1, 128.4, 128.5, 136.4,
136.7, 150.9, and 163.5 ppm. Anal. Calcd for C95H71Li3O6N7La:
C, 72.85; H, 4.57; N, 6.26; Found: C, 72.98; H, 4.78; N, 6.12.34
4.3.2. Crystallization of Li3(py)5(BINOLate)3Yb(py) (4-Yb). The
synthesis of 4-Yb was obtained by room-temperature diffusion of
La(O3SCF3)3 (0.500 g, 0.853 mmol) was added as a solid to this
clear solution. After 30 min, La(O3SCF3)3 completely dissolved,
and the cloudy solution once again became clear. This mixture
stirred for an additional hour, and DMEDA (0.300 mL, 0.248 g,
2.82 mmol) was added. The clear solution was stirred for a total of
3 days and filtered through dried Celite, the filtrate was recovered,
and the volatiles were removed under reduced pressure. The
remaining solid was dissolved in CH2Cl2, the insoluble materials
were removed by filtration through Celite, and the filtrate was
collected. The solvent was then removed under reduced pressure
to yield a white solid. Washing this solid with diethyl ether and
drying it under reduced pressure gave 0.790 g of 5-La [73% yield
based on La(O3SCF3)3]. Crystals of 5-La were obtained by slow
diffusion of pentane into a THF solution containing this compound
1
at room temperature: H NMR (300 MHz, THF-d8, 25 °C, TMS)
δ ) 0.61 (br s, 2H, NH), 1.60 (s, 6H, N-CH3), 1.69 (br d, 2H,
N-CH2), 1.96 (br d, 2H, N-CH2), 6.83 (d, 2H), 6.91 (m, 4H), 7.23
(d, 2H), and 7.67 (t, 4H) ppm; 13C{1H} NMR (75 MHz, THF-d8)
δ ) 36.1 (N-CH3), 50.7 (N-CH2), 119.4, 120.4, 125.0, 126.1, 127.2,
127.9, 128.2, 128.6, 136.6, and 163.8; IR (KBr) ν ) 3341, 3299,
3043, 2981,2952, 2890, 2855, 2802, 1612, 1588, 1553, 1499, 1463,
1422, 1342, 1283, 1247, 1177, 1140, 1096, 1069, 994, 959, 935,
882, 822, 746, 665, 632, 591, 574 cm-1. Anal. Calcd for
C72H72Li3O6N6La: C, 67.71; H, 5.68; N, 6.58. Found: C, 67.35; H,
5.67; N, 6.30.34
4.4.2. Synthesis of Li3(DMEDA)3(BINOLate)3Eu (5-Eu) from
Eu(O3SCF3)3. General procedure C was followed to prepare 5-Eu.
The reagents used are as follows: Li2(R-BINOLate) (0.745 g, 2.50
mmol), Eu(O3SCF3)3 (0.500 g, 0.834 mmol), and DMEDA (0.295
mL, 0.244 g, 2.77 mmol) in 60 mL of THF. Compound 5-Eu (0.650
g) was obtained as a yellow solid in 61% yield based on
Eu(O3SCF3)3. Crystals of 5-Eu can be obtained by slow diffusion
of pentane into a THF solution containing this compound at room
temperature: 1H NMR (300 MHz, THF-d8, 25 °C, TMS) δ ) -9.16
(br s, 2H, NH), -3.82 (br s, 2H, N-CH2), -3.59 (br s, 2H, N-CH2),
0.366 (s, 6H, N-CH3), -1.69 (d, 2H), 3.04 (t, 2H), 5.56 (t, 2H),
7.65 (d, 2H), 13.76 (br s, 2H), 40.56 (br s, 2H) ppm; 13C{1H} NMR
(75 MHz, THF-d8) δ ) 33.2 (N-CH3), 43.8 (N-CH2), 86.0, 116.4,
116.9, 122.1, 122.6, 128.6, 130.5, 132.4, 134.5, and 180.4 ppm;
IR (KBr) ν ) 3342, 3299, 3043, 2985, 2952, 2875, 2856, 2803,
1612, 1589, 1554, 1501, 1463, 1423, 1342, 1283, 1248, 1175, 1138,
1096, 1069, 995, 959, 935, 898, 821, 746, 665, 642, 591, 574 cm-1
.
Anal. Calcd for C72H72Li3O6N6Eu·THF: C, 67.01; H, 5.92; N, 6.17.
Found: C, 67.26; H, 6.35; N, 5.99.34
4.4.3. Synthesis of Li3(DMEDA)3(BINOLate)3Lu (5-Lu) from
Lu(O3SCF3)3. General procedure C was followed to prepare 5-Lu.
The reagents used are as follows: Li2(R-BINOLate) (0.719 g, 2.41
mmol), Lu(O3SCF3)3 (0.500 g, 0.804 mmol), and DMEDA (0.285
mL, 0.234 g, 2.65 mmol) in 60 mL of THF. Compound 5-Lu (0.665
g) was obtained as a white solid in 63% yield based on
Lu(O3SCF3)3. Crystals of 5-Lu were obtained by slow diffusion of
pentane into a THF solution containing this compound at room
temperature: 1H NMR (300 MHz, THF-d8, 25 °C, TMS) δ ) -0.54
(br s, 2H, N-H), 1.46 (br d, 2H, N-CH2), 1.63 (s, 6H, N-CH3),
1.77 (br d, 2H, N-CH2), 6.87 (br-d, J ) 3.65, 12H), 6.95 (m, 6H),
7.39 (d, J ) 8.73, 6H), 7.69 (d, J ) 7.98, 6H), 7.77 (d, J ) 8.82,
6H) ppm; 13C{1H} NMR (75 MHz, THF-d8) δ 36.2 (N-CH3), 50.2
(N-CH2), 119.1, 121.2, 125.5, 126.0, 127.1, 128.5, 128.6, 128.6,
136.3, and 163.0 ppm.
pentane into
a pyridine (1.0 mL) solution of Li3(THF)3-
(BINOLate)3Yb (1-Yb, 0.108 mg) under anhydrous conditions.
After several days, pale crystals formed that were suitable for an
X-ray diffraction study: 1H NMR (300 MHz, THF-d8, 25 °C, TMS)
δ ) 7.60 (br s, 16H, py), 7.93 (t, J(H,H) ) 7.4 Hz, 8H, py), 9.31
(br s, 16H, py), -13.22 (br s, 6H), -1.05 (br s, 6H), 2.84 (br s,
6H), 8.08 (d, J(H,H) ) 7.89 Hz, 6H), 23.00 (br s, 6H), 85.04 (br
s, 6H) ppm; 13C{1H} NMR (75 MHz, THF-d8) δ ) 58.1, 108.2,
110.8, 114.1, 116.2, 121.4, 123.9, 124.4, 125.2, 137.1, 139.8, 152.4,
and 177.3 ppm. Anal. Calcd for C90H66Li3O6N6Yb·2py: C, 71.51;
H, 4.56; N, 6.67; Found: C, 71.18; H, 4.49; N, 6.75.35
4.3.3. Crystallization of Li3(py)5(BINOLate)3Eu(py) (4-Eu).
Li3(THF)3(BINOLate)3Eu (1-Eu, 0.108 g) was added to a vial and
dissolved in 1.0 mL of pyridine. This vial was then placed inside
of a 20 mL screw-capped vial that was half-filled with dry pentane.
After several days, yellow crystals formed that were suitable for
an X-ray diffraction study.
4.4.4. Synthesis of Li3(DMEDA)3(BINOLate)3Y (5-Y) from
Y(O3SCF3)3. General procedure C was followed to prepare 5-Y.
The reagents used are as follows: Li2(R-BINOLate) (0.834 g, 2.80
mmol), Y(O3SCF3)3 (0.500 g, 0.933 mmol), and DMEDA (0.331
mL, 0.271 g, 3.08 mmol) in 60 mL of THF. Compound 5-Y (0.772
g) was obtained as a white solid in 67% yield based on Y(O3SCF3)3.
Crystals of 5-Y were obtained by slow diffusion of pentane into a
THF solution containing this compound at room temperature: H
NMR (300 MHz, THF-d8, 25 °C, TMS) δ ) -0.29 (br s, 2H,
N-H), 1.61 (br d, 2H, N-CH2), 1.70 (s, 6H, N-CH3), 1.89 (br d,
4.4. General Procedure C: Synthesis of Li3(DMEDA)3-
1
(BINOLate)3Ln (5-Ln) Complexes from Ln(O3SCF3)3. 4.4.1. Syn-
thesis of Li3(DMEDA)3(BINOLate)3La (5-La). Li2(R-BINOLate)
(0.763 g, 2.56 mmol) was dissolved in 60 mL of THF, and
9
7418 J. AM. CHEM. SOC. VOL. 130, NO. 23, 2008