2824 Organometallics, Vol. 19, No. 15, 2000
Communications
[(CpTi)6(µ3-Te)6(µ3-O)2],7 respectively. The reaction of 1
with K (or Na) gives nonextractable titanium-containing
solids. The yield of the single crystals of 2 is small. The
filtrate was concentrated and kept at -20 °C; over 2
weeks a yellow solid was formed. From the elemental
analysis, the solid was impure 2, which was difficult to
purify.
Compounds 2 (yellow) and 3 (green) are crystalline
solids,8 which are thermally very stable. 2 starts to
decompose at 300 °C, while 3 is stable above the melting
point (301 °C). Under an inert atmosphere or in solution
(toluene) no decomposition was observed for 2 and 3.
However, 3 is sensitive to air and moisture. The IR
spectrum of 2 shows a broad absorption at 3381 cm-1
,
assignable to the N-H stretching frequency. We were
not able to dissolve compound 2 without decomposition
to obtain reliable NMR spectra. The largest fragment
in the EI mass spectrum of 2 was observed at m/e 2537
(M+ - NSiMe3) with very low intensity due to the poor
volatility of 2. Compound 3 exhibits the peak of the
molecular ion at m/e 879 with 62% relative intensity
(190, 100%).
F igu r e 1. Structure of the inorganic core of 2 in the
crystal. Selected bond lengths (Å) and angles (deg): Ti-
(1)-N(2) ) 1.958(5), Ti(1)-N(1) ) 1.998(6), Ti(1)-N(1)#1
) 2.003(6), Ti(1)-N(1)#2 ) 2.014(5), Ti(1)-N(4) ) 2.193-
(4), Ti(1)-N(3) ) 2.196(4); N(2)-Ti(1)-N(1) ) 123.5(3),
N(2)-Ti(1)-N(1)#1 ) 78.6(2), N(1)-Ti(1)-N(1)#1 ) 75.2-
(2), N(2)-Ti(1)-N(1)#2 ) 78.3(2), N(1)-Ti(1)-N(1)#2 )
75.0(2), N(1)#1-Ti(1)-N(1)#2 ) 122.1(4), Ti(1)#3-Ti(1)-
Ti(1)#4 ) 60.0, Ti(1)#3-Ti(1)-Ti(1)#2 ) 90.0, Ti(1)#4-Ti-
(1)-Ti(1)#2 ) 60.94(2), Ti(1)#3-Ti(1)-Ti(1)#1 ) 60.94(2),
Ti(1)#4-Ti(1)-Ti(1)#1 ) 90.0, Ti(1)#2-Ti(1)-Ti(1)#1 )
58.12(4).
(4) (a) Synthesis of 2: Ammonia (40 mL) was condensed onto a
solution of 1 (1.35 g, 2.01 mmol) in toluene (60 mL) with stirring at
-78 °C. NaNH2 (0.16 g, 4.10 mmol) was added to the resulting mixture.
The mixture was stirred for 1 h at -78 °C. Then the excess of ammonia
was allowed to evaporate from the reaction mixture under stirring over
4 h. During this period the mixture was warmed slowly to room
temperature. After filtration and partial removal of the solvent in
vacuo, the resulting reddish brown solution was kept at room tem-
perature for 3 weeks. Yellow single crystals of 2 were obtained in a
yield of 0.05 g. After concentration of the filtrate (to ca. 10 mL) and
addition of hexane (15 mL), the solution was kept at -20 °C for 2
weeks. A yellow solid of impure 2 (0.21 g) was formed. (b) Synthesis of
3: Ammonia (50 mL) was condensed onto a suspension of 1 (2.02 g,
3.0 mmol) and K (0.24 g, 6.0 mmol) in toluene (80 mL) at -78 °C with
stirring. The stirring of the mixture was continued for 1 h at this
temperature. Then the excess ammonia was allowed to evaporate from
the reaction mixture over 4 h. During this period the mixture was
slowly warmed to room temperature. After filtration and concentration
to about 15 mL in vacuo, the dark green solution was kept at -20 °C
for 2 weeks. Green crystals of 3 were obtained: yield 0.87 g.
(5) Huffman, J . C.; Stone, J . G.; Krusell, W. C.; Caulton, K. G. J .
Am. Chem. Soc. 1977, 99, 5829.
(6) Bottomley, F.; Egharevba, G. O.; White, P. S. J . Am. Chem. Soc.
1985, 107, 4353.
(7) Gindelberger, D. E. Acta Crystallogr. Sect. C 1996, 52, 2493.
(8) (a) Characterization data for 2. Dec pt: 300-330 °C. IR (Nujol):
ν˜ 3381, 1612, 1441, 1248, 994, 845, 728, 473 cm-1. EI-MS: m/e 2537
(M+ - NSiMe3). Anal. Calcd for C126H204N20Si12Ti6 (2623.6): N, 10.7;
Ti, 11.0. Found: N, 10.7; Ti, 11.7. (b) Characterization data for 3. Mp:
301 °C. IR (Nujol): ν˜ 1613, 1457, 1385, 1244, 981, 844, 758, 466 cm-1
.
1H NMR (200 MHz, C6D6): δ 8.58-8.62 (m, 6H, C6H4), 8.31-8.34 (m,
6H, C6H4), 2.16 (s, 9H, ArMe), 0.21 (br, 54H, SiMe3, ∆ν1/2 ) 5.9 Hz).
EI-MS: m/e (%) 879 (62) (M+), 190 (100) (L+ - NSiMe3). Anal. Calcd
for C42H75N6Si6Ti (880.52): C, 57.3; H, 8.6; N, 9.5; Ti, 5.4. Found: C,
58.0; H, 8.8; N, 9.9; Ti, 5.2.
(9) (a) X-ray structure determination of 2: Single crystals of 2
suitable for X-ray structural analysis were obtained from toluene by
keeping the reaction mixture at room temperature for 3 weeks. Data
for the structure were collected on a Stoe-Siemens-Huber diffracto-
meter with a Siemens CCD area detector with graphite-monochro-
mated Mo KR radiation (λ ) 0.710 73 Å). Intensity measurements were
performed at 133(2) K on a rapidly cooled crystal in an oil drop.13 The
structure was solved by direct methods (SHELXS-90)14 and refined
with all data by full-matrix least squares on F2.15 The hydrogen atoms
of N-H bonds (occupancy 0.75) and those of C-H bonds were added
in idealized positions. Other details of the data collection, structure
solution, and refinement are listed in Table 1. (b) X-ray structure
determination of 3: Single crystals of 3 suitable for X-ray structural
analysis were obtained from toluene by keeping the reaction mixture
at -20 °C for 2 weeks. Data for the structure were collected on a Stoe-
Siemens-AED2 four-circle diffractometer with graphite-monochro-
mated Mo KR radiation (λ ) 0.710 73 Å). Intensity measurements were
performed at 200(2) K on a crystal in an oil drop. The structure was
solved by direct methods (SHELXS-90)14 and refined with all data by
full-matrix least squares on F2.15 Hydrogen atoms were added in
idealized positions. Other details of the data collection, structure
solution, and refinement are listed in Table 1.
F igu r e 2. Molecular structure of 3 in the crystal. Selected
bond lengths (Å) and angles (deg): Ti(1)-N(3) ) 2.133(5),
Ti(1)-N(6) ) 2.154(5), Ti(1)-N(2) ) 2.160(4), Ti(1)-N(1)
) 2.164(5), Ti(1)-N(5) ) 2.177(4), Ti(1)-N(4) ) 2.188(5);
N(3)-Ti(1)-N(6) ) 160.1(2), N(3)-Ti(1)-N(2) ) 95.3(2),
N(6)-Ti(1)-N(2) ) 102.5(2), N(3)-Ti(1)-N(1) ) 102.2(2),
N(6)-Ti(1)-N(1) ) 93.7(2), N(2)-Ti(1)-N(1) ) 63.6(2),
N(3)-Ti(1)-N(5) ) 101.1(2), N(6)-Ti(1)-N(5) ) 63.4(2),
N(2)-Ti(1)-N(5) ) 160.6(2), N(1)-Ti(1)-N(5) ) 102.4(2),
N(3)-Ti(1)-N(4) ) 63.7(2), N(6)-Ti(1)-N(4) ) 102.5(2),
N(2)-Ti(1)-N(4) ) 105.2(2), N(1)-Ti(1)-N(4) ) 162.3(2),
N(5)-Ti(1)-N(4) ) 91.4(2).
X-r a y Cr ysta l Str u ctu r es of 2 a n d 3. The central
inorganic core of 2 and the molecular structure of 39
are shown in Figures 1 and 2, respectively. Details of