COMMUNICATIONS
by crystallization from benzene/CH3CN. 1H NMR (500 MHz, CDCl3,
258C): d 1.74 (br s, 40H), 1.23 (br s, 40H), 1.02 (br m, 2H), 0.80 (br m,
6H); 13C{1H} NMR (125 MHz, CDCl3, 258C): d 27.32, 27.30, 27.04, 26.73,
26.70, 26.41, 25.61 (CH2), 23.20, 22.87, 22.84 (2:1:1 for CH); 29Si{1H} NMR
(99 MHz, CDCl3, 258C): d 67.38, 67.76, 69.34 (1:1:2); MS (70 eV,
groups. We have only begun to explore these possibilities, but
our preliminary work with nBuB(OH)2 and K2CrO4/
[18]crown-6 is very encouraging. In the case of nBuB(OH)2,
the addition of freshly purified nBuB(OH)2 to a solution of 6
in C6H6/Et3N produces 11 and variable amounts of 4. We
suspect that 4 is formed by the reaction of 6 with water rather
than a direct reaction of 6 with the boronic acid because
nBuB(OH)2 is extremely difficult to dry without effecting its
cyclotrimerization[16] and because the reaction of 6 with traces
of water is known to produce 4.[12] In the case of K2CrO4/
[18]crown-6, extensive decomposition of the chromium re-
agent is observed during the reaction, but multinuclear NMR
spectra clearly indicate that 12 is produced in approximately
20% yield. Authentic 12 can be prepared in high yield by the
reaction of 7 with CrO3/MgSO4 in CCl4.[17]
In summary, we have developed a new and potentially
general method for synthesizing discrete heterosilsesquioxane
frameworks. This method, which introduces heteroatoms by
nucleophilic substitution on framework Si atoms rather than
electrophilic substitution on framework O atoms, provides
access to a wide range of new compounds, including poly-
hedral clusters that are formally derived from replacement of
a framework oxygen atom in 4 by a heteroatom or other
divalent bridging group.
2008C, relative intensity): m/z: 1077.7 ([M Cy] , 100); elemental analyis
calcd for C48H88O15SSi8 (found): C 49.62 (49.45), H 7.63 (7.67).
11: A solution of nBuB(OH)2 (27.9 mg, 0.274 mmol) in benzene (0.5 mL)
was added to a solution of 6 (152.6 mg, 0.112 mmol) and Et3N (60.8 mg,
0.601 mmol) in benzene (3 mL) and stirred for 0.5 h at 258C. Evaporation
of the solvent, extraction with benzene (10 mL), concentration to ꢁ 1 mL
and addition of CH3CN (10 mL) afforded 127 mg of a white powder
containing 11 and 4 in a ratio of 81:19. Attempts to separate 11 and 4 by
extraction or fractional crystallization were unsuccessful. For 11: 1H NMR
(500 MHz, CDCl3, 258C): d 1.74 (br s, 40H), 1.36 (m, 2H), 1.23 (44H),
0.88 (t, 3H), 0.74 (br s, 8H); 13C{1H} NMR (125 MHz, CDCl3, 258C): d
27.57, 27.55, 27.51, 26.91, 26.76, 26.56, 25.23, 17.36, 16.63 (s for CH2), 24.00,
23.66, 23.12 (s for CH, 1:2:1), 14.07 (CH3); 29Si{1H} NMR (99 MHz, CDCl3,
258C): d 67.39, 69.58, 69.94 (1:2:1); MS (70 eV, 2008C, relative
intensity): m/z: 1107 ([M Bu] , 20%), 1081 ([M Cy] , 100%).
12 was prepared as a bright orange solid in 55% yield (87 mg) from 7
(148 mg, 0.135 mmol), CrO3 (133 mg, 1.330 mmol), and MgSO4 (371 mg) in
CCl4 (4 mL) according to the procedure described in ref. [17]. 1H NMR
(500 MHz, CDCl3, 258C): d 1.75 (br m, 40H), 1.24 (br m, 40H), 0.87 (br
m, 2H), 0.78 (br m, 6H); 13C{1H} NMR (125 MHz, CDCl3, 258C): d 27.54,
27.49, 27.46, 27.40, 26.83, 26.69, 26.66, 26.54, 26.51 (s for CH2), 23.76, 23.68,
23.02 (s for CH, 1:2:1); 29Si{1H} NMR (99 MHz, CDCl3, 258C): d 62.19,
67.14, 69.68 (1:1:2).
Received: April 22, 1998 [Z11767IE]
German version: Angew. Chem. 1998, 110, 2808 ± 2811
Experimental Section
8: A solution of aniline (98 mg, 1.1 mmol) in benzene (1 mL) was added
dropwise to a solution of 6 (308 mg, 0.23 mmol) and triethylamine (45 mg,
0.45 mmol) in benzene (2 mL). After stirring the resulting emulsion for 1 h
at 258C, the benzene layer was decanted from the ammonium triflate. The
oily ammonium triflate was rinsed twice with benzene (0.5 mL). The
combined benzene fractions were evaporated to dryness under reduced
pressure to afford 8 as a microcrystalline white solid (201 mg, 71%). The
product obtained in this manner is spectroscopically pure (1H, 13C, 29Si
NMR); colorless crystals were obtained by recrystallization from hexanes.
1H NMR (500 MHz, CDCl3, 258C): d 7.20 (t, J 7.7 Hz, 4H), 6.79 (t, J
7.8 Hz, 2H), 6.68 (d, J 7.3 Hz, 4H), 3.73 (br s, 2H), 1.86 (br m, 40H), 1.34
(br m, 40H), 1.00 (br m, 2H), 0.89 (br m, 6H); 13C{1H} NMR (125 MHz,
CDCl3, 258C): d 145.68, 128.82, 118.16, 117.41, 27.635, 27.508, 26.937,
26.902, 26.867, 26.826, 26.632, 26.546 (CH2), 24.75, 24.14, 23.06 (1:2:1 for
CH); 29Si{1H} NMR (99 MHz, CDCl3, 258C): d 51.91, 67.41, 69.77
(1:1:2); elemental analysis calcd for C60H100N2O11Si8 (found): C 57.65
(57.81), H 8.06 (7.87), N 2.24 (2.63); m.p. 164.78C (by differential scanning
calorimetry).
Keywords: cage compounds ´ silicon
[1] J. F. Brown, L. H. Vogt, J. Am. Chem. Soc. 1965, 87, 4313 ± 4317.
[2] F. J. Feher, D. A. Newman, J. F. Walzer, J. Am. Chem. Soc. 1989, 111,
1741 ± 1748.
[3] F. J. Feher, T. A. Budzichowski, Polyhedron 1995, 14, 3239 ± 3253.
[4] R. Murugavel, V. Chandrasekhar, H. W. Roesky, Acc. Chem. Res.
1996, 29, 183 ± 189.
[5] J. D. Lichtenhan, Comments Inorg. Chem. 1995, 17, 115 ± 130.
[6] P. G. Harrison, J. Organometal. Chem. 1997, 542, 141 ± 183.
[7] W. A. Herrmann, R. Anwander, V. Dufaud, W. Scherer, Angew.
Chem. 1994, 106, 1338 ± 1340; Angew. Chem. Int. Ed. Engl. 1994, 33,
1285 ± 1286.
[8] M. Crocker, R. H. M. Herold, A. G. Orpen, Chem. Commun. 1997,
2411 ± 2412.
[9] T. Maschmeyer, M. C. Klunduk, C. M. Martin, D. S. Shepard, J. M.
Thomas, B. F. G. Johnson, Chem. Commun. 1997, 1847 ± 1848.
[10] V. Ruffieux, G. Schmid, P. Braunstein, J. Rose, Chem. Eur. J. 1997, 3,
900 ± 903.
[11] H. C. L. Abbenhuis, S. Krijnen, R. A. van Santen, Chem. Commun.
1997, 331 ± 332.
[12] F. J. Feher, D. Soulivong, A. E. Eklund, Chem. Commun. 1998, 399 ±
400.
9: A solution of aniline (11.9 mg, 0.128 mmol) in benzene (0.5 mL) was
added dropwise to a solution of 6 (159.0 mg, 0.117 mmol) and triethylamine
(34.1 mg, 0.337 mmol) in benzene (2 mL). Workup as described above for 8
and precipitation from CHCl3/CH3CN affords 9 as an analytically pure
white powder (115 mg, 85%). 1H NMR (500 MHz, CDCl3, 258C): d 7.13
(m, 4H), 7.05 (m, 1H), 1.69 ± 1.58 (br s, 35H), 1.47 ± 1.39 (br m, 10H), 1.20 ±
1.12 (br s, 35H), 0.95 ± 0.82 (br s, 10H), 0.70 ± 0.65 (br s, 6H), 0.22 (m, 2H);
13C{1H} NMR (125 MHz, CDCl3, 258C): d 142.66, 130.94, 128.56, 125.20
(s for Cꢁs aromatic), 27.60, 27.55, 26.92, 26.87, 26.75, 26.71, 26.68, 26.55
(CH2), 23.48, 23.21, 23.11 (s for CH, 2:1:1); 29Si{1H} NMR (99 MHz, CDCl3,
258C): d 55.52, 67.81, 68.26 (1:2:1); MS (70 eV, 2008C, relative
[13] Crystal data for 8: M 1250.14, monoclinic, space group P21/c, a
1023.02(5), b 2610.18(13), c 2519.10(12) pm, b 97.538(1)8, V
6.6685(6) nm3, Z 4, 1calcd 1.245 Mgm
,
F(000) 2696, l
3
1
71.073 pm, T 158 K, m(MoKa) 0.218 mm
,
crystal dimensions:
0.09 Â 0.23 Â 0.30 mm, 2.268 ꢂ 2q ꢂ 56.68; of the 40533 collected
reflections, 15573 are independent, and these were used for the
refinement of 786 parameters; maximal residual electron density:
539 enm 3, R1(F > 4s(F)) 0.068 and wR2 0.147 (all data) with
R1 SjjFoj jFcjj/SjFoj and wR2 (Sw(F2o Fc2)2/Sw(Fo2)2)0.5. Crystal
data for 10: M 1161.96, monoclinic, space group P21/n, a
intensity): m/z: 1156 ([MH] , 35%), 1072 ([M Cy] , 100%); elemental
analysis calcd for C54H93NO11Si8 (found): C 56.06 (55.43), H 8.10 (8.12), N
1.21 (1.41); m.p. 358.78C (by differential scanning calorimetry).
10: A solution of 6 (295.4 mg, 0.217 mmol) in benzene (3 mL) was added to
a solution Bu4NHSO4 (162.3 mg, 0.478 mmol) in benzene (3 mL) and
stirred for 1 h. The colorless benzene solution was decanted and
evaporated to dryness (258C, 0.01 Torr) to afford a white solid, which
was washed with CH3CN and dried in vacuo to afford spectroscopically
pure 10 (196 mg, 90%). Analytically pure, colorless crystals were obtained
1558.20(7), b 1847.80(9), c 2093.07(10) pm, b 100.106(1)8, V
5.9330(5) nm3, Z 4, 1calcd 1.301Mgm
,
F(000) 2496, l
3
1
71.073 pm, T 158 K, m(MoKa) 0.277 mm
,
crystal dimensions:
0.13 Â 0.21 Â 0.22 mm, 2.968 ꢂ 2q ꢂ 56.68; of the 37062 collected
Angew. Chem. Int. Ed. 1998, 37, No. 19
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 1998
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