Reductive Reactivity of the Organolanthanide Hydrides
A R T I C L E S
Reaction of 1 with Anthracene. As described for 4, C14H10 (8
mg, 0.020 mmol) was added to 1 (2 mg, 0.010 mmol). As the
mixture slowly warmed from -35 °C to room temperature, the color
changed from brown to dark brown-green and bubbles were
1473s, 1435s, 1380m, 1089s, 1023s, 732s, 689s cm-1. Anal. Calcd.
for C52H70S2Y2: Y, 19.5. Found: 19.0. A similar reaction was carried
out with PhSSPh (2 mg, 0.01 mmol) and 3 (7 mg, 0.01 mmol) in
cyclohexane-d12 in a sealed J-young tube. After 20 min, the 1H
NMR spectra showed complete conversion of the starting material
to new products displaying resonances consistent with H2 and 13.
(C5Me5)Y(η5-C5Me4CH2-C5Me4CH2-η3), 16. C8H8 (2.4 µL,
0.021 mmol) was added via syringe to a stirred slurry of 3 (15 mg,
0.021 mmol) in 0.5 mL of benzene-d6. The white slurry immediately
changed to a deep red. The formation of previously characterized
(C5Me5)Y(C8H8), 14,33,34 and tetramethylfulvene was observed
along with a new resonance in the 1H NMR spectrum at 2.01 ppm.
Red crystals of 16 suitable for X-ray diffraction were grown via
slow evaporation of the solution at 25 °C in an NMR tube. Yellow
crystals of 14 suitable for X-ray diffraction were also isolated and
structurally characterized. 13C NMR spectroscopy revealed the
presence of (C5Me5)3Y, 15,25 whose 1H NMR resonance overlapped
with the 2.01 ppm resonance. On the basis of these overlapping
resonances the maximum yield of 16 appears to be less than 50%
of that obtained for 14.
1
observed. H NMR spectroscopy showed the conversion of 1 to
previously characterized [(C5Me5)2Sm]2(µ-η3:η3-C14H10),29 8, and
a resonance at 4.46 ppm was indicative of the formation of H2,
along with unreacted starting material, 1. In addition to the 1.26
and 1.42 ppm resonances of 8, three other resonances of similar
intensity in the (C5Me5)1- region were observed at 1.50, 1.11, and
0.40 ppm.
[(C5Me5)2La(µ-SPh)]2, 9. PhSSPh (26 mg, 0.12 mmol) was
added to a stirred solution of pale-yellow [(C5Me5)2LaH]x, 2, (97
mg, 0.12 mmol) in benzene (5 mL). The color changed to a lighter
yellow and bubbles were observed. After the mixture was stirred
for 12 h, the pale-yellow solution was evaporated to yield 9 as a
pale-yellow crystalline powder (112 mg, 91%). 1H NMR (500 MHz,
3
benzene-d6) δ 2.17 (s, 30H, C5Me5), 6.97 (t, 1H, JHH ) 7 Hz,
p-H), 7.13 (t, 2H, 3JHH ) 7 Hz, m-H), 7.23 (d, 3JHH ) 8 Hz, o-H).
13C NMR (125 MHz, benzene-d6) δ 12.5 (C5Me5), 122.9 (C5Me5),
124.5 (p-phenyl), 129.4 (m-phenyl), 132.4 (o-phenyl). IR (KBr)
3059w, 2906s, 2856s, 2726w, 1579m, 1474s, 1436m, 1379w,
1083m, 1024m, 737vs, 692s cm-1. Anal. Calcd for C52H70S2La2:
C, 60.23; H, 6.80; S, 6.18; La, 26.79. Found: C, 58.93; H, 6.19; S,
6.08; La, 27.6. A similar reaction was carried out with PhSSPh (3
mg, 0.02 mmol) and 2 (10 mg, 0.02 mmol) in benzene-d6 in a sealed
J-Young tube. After 20 min, the 1H NMR spectra showed complete
conversion of starting materials to new products displaying
resonances consistent with the formation of H2 (4.46 ppm) and 9.
Reaction of 2 with Phenazine. As described for 4, C12H8N2 (3
mg, 0.016 mmol) was added to 2 (13 mg, 0.032 mmol). As the
mixture slowly warmed from -35 °C to room temperature, the color
changed from pale yellow to bright red and bubbles were observed.
1H NMR spectroscopy showed the conversion of 2 to previously
characterized [(C5Me5)2La]2(µ-η3:η3-C12H8N2), 10,31 and a reso-
nance at 4.46 ppm was indicative of the formation of H2. In addition
to the 2.06 ppm (C5Me5)1- resonance of 10, two other (C5Me5)1-
resonances at 1.96 and 1.82 ppm were observed each with 1.5 times
the intensity of that of the 2.06 resonance.
(C5Me5)2Y(µ-η8:η1-C8H7)Y(C5Me5), 17. C8H8 (7 µL, 0.065
mmol) was added via syringe to a suspension of 3 (46 mg, 0.065
mmol) stirred in cyclohexane. Upon addition, a transient dark-purple
color immediately formed that quickly turned red. The solution was
stirred for 1.5 h, and the solvent was removed under vacuum leaving
a bright red-orange powder. Pale-orange crystals of 17 (7 mg, 15%)
suitable for X-ray diffraction were selectively grown from a
saturated solution of hexanes at -35 °C over 24 h. After isolation
of 17, solvent was removed under vacuum leaving a red-orange
powder. 1H NMR spectroscopy showed
a 1:1 ratio of
(C5Me5)Y(C8H8), 14: (C5Me5)3Y, 15.25 1H NMR (500 MHz,
cyclohexane-d12) δ 6.24 (m, 2H, C8H7), 6.15 (m, 3H, C8H7), 5.53
3
(d, 2H, JHH ) 9 Hz, C8H7), 2.07 (s, 15H, C5Me5), 1.77 (s, 15H,
C5Me5), 1.18 (s, 15H, C5Me5). 13C NMR (cyclohexane-d12) δ 157.0
1
(C8H7, d, JYC ) 34 Hz), 118.7 (C5Me5), 118.2 (C5Me5), 116.0
(C5Me5), 97.9 (C8H7, d, 1JYC ) 3 Hz, ꢀ-C), 97.5 (C8H7, d, 1JYC
)
1
3 Hz, γ-C), 96.8 (C8H7, dd, JYC ) 4 Hz, R-C), 95.2 (C8H7, d,
1JYC ) 4 Hz, δ-C), 11.8 (C5Me5), 10.6 (C5Me5), 10.1 (C5Me5). IR
(KBr) 2947s, 2905s, 2857s, 2725m, 2591m, 1429s, 1377s, 1021m,
872s, 742s, 711s cm-1. Anal. Calcd for C38H52Y2: C, 66.47; H,
7.63. Found: C, 67.06; H, 8.25.
Reaction of 2 with Cyclooctatetraene. As described for 4, C8H8
(2 µL, 0.020 mmol) was added via syringe to 2 (16 mg, 0.039
mmol). As the mixture warmed to room temperature, a transient
purple solution formed. Subsequently (∼10 min), the color changed
Reaction of (C5Me5)Y(C8H8), 14, with (C5Me5)3Y, 15. 15 (9
mg, 0.018 mmol) was added to a solution of 14 (4 mg, 0.012 mmol)
in cyclohexane-d12 (0.6 mL). The solution immediately turned red.
After 2 days, resonances consistent with 17 and C5Me5H as well
as both unreacted starting materials, (C5Me5)Y(C8H8) and
1
from pale yellow to orange, and bubbles were observed. The H
NMR spectrum contained several resonances in the (C5Me5)1-
region, but the resonance at 2.00 ppm that matched that reported
for (C5Me5)3La, 1232 was predominant. A resonance at 4.46 ppm
matched that for H2. Addition of THF to the sample generated the
1.80 and 6.36 ppm resonances of previously characterized
(C5Me5)La(C8H8)(THF).33,34
1
(C5Me5)3Y, were observed by H NMR spectroscopy.
Reaction of 17 with H2. A J-Young tube containing a suspension
of 17 (10 mg, 0.01 mmol) in cyclohexane-d12 was attached to a
high vacuum line. The suspension was degassed by three
freeze-pump-thaw cycles, and 1 atm of H2 was introduced. The
solution gradually became a darker pink color and all solids
dissolved. After 2 h 1H NMR spectroscopy showed resonances
consistent with the formation of (C5Me5)Y(C8H8), 14, and
[(C5Me5)2YH]2, 3 in a 2:1 ratio.
X-ray Data Collection, Structure Solution and Refinement.
[(C5Me5)2La(µ-SPh)]2, 9. A colorless crystal of approximate
dimensions 0.25 mm × 0.30 mm × 0.50 mm was mounted on a
glass fiber and transferred to a Bruker CCD platform diffractometer.
The SMART35 program package was used to determine the unit
cell parameters and for data collection (20 s/frame scan time for a
sphere of diffraction data). The raw frame data was processed using
SAINT36 and SADABS37 to yield the reflection data file. Subse-
[(C5Me5)2Y(µ-SPh)]2, 13. PhSSPh (30 mg, 0.14 mmol) was
added to a stirred suspension of pale-pink [(C5Me5)2YH]2, 3, (100
mg, 0.14 mmol) in hexane (5 mL). The color changed to a light
yellow and bubbles were observed. After the mixture was stirred
for 30 min, the pale-yellow solution was evaporated to yield 13 as
a pale-yellow powder (117 mg, 90%). Crystals of 13 suitable for
X-ray diffraction were grown at -35 °C from a concentrated toluene
1
solution. H NMR (500 MHz, cyclohexane-d12) δ 2.00 (s, C5Me5,
3
3
60H), 6.88 (d, 4H, JHH ) 8 Hz, m-H), 6.92 (t, 2H, JHH ) 7 Hz,
p-H), 7.01 (m, 4H,3JHH ) 7 Hz, o-H) 13C NMR (125 MHz,
cyclohexane-d12) δ 12.3 (C5Me5), 121.0 (C5Me5), 124.5 (m-phenyl),
130.0 (o-phenyl), 131.7 (p-phenyl). IR (KBr) 2910s, 2859s, 1578s,
(31) Scholz, J.; Scholz, A.; Weinmann, R.; Janiak, C.; Schumann, H. Angew.
Chem., Int. Ed. Engl. 1994, 33, 1171.
(35) SMART Software Users Guide,Version 5.1; Bruker Analytical X-ray
Systems, Inc.: Madison, WI, 1999.
(36) SMART Software Users Guide,Version 6.0; Bruker Analytical X-ray
Systems, Inc.: Madison, WI, 1999.
(37) Sheldrick G. M., SADABS, Version 2.10; Bruker Analytical X-ray
Systems, Inc.: Madison, WI, 2002.
(32) Evans, W. J.; Davis, B. L.; Ziller, J. W. Inorg. Chem. 2001, 40, 6341.
(33) Bruin, P.; Booij, M.; Teuben, J. H.; Oskam, A. J. Organomet. Chem.
1988, 350, 17.
(34) Schumann, H.; Kohn, R. D.; Reier, F.-W.; Dietrich, A.; Pickardt, J.
Organometallics 1989, 8, 1388.
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J. AM. CHEM. SOC. VOL. 130, NO. 26, 2008 8557