Intramolecularly Coordinated Azidoalanes
Organometallics, Vol. 17, No. 2, 1998 165
(1c and 3b) or according to the literature.11 The IR spectra
were recorded on a Perkin-Elmer FTIR 1720x in toluene.
Mass spectra were obtained on a Finnigan MAT 95 (70 eV).
Elemental analyses (C, H, N) were measured on either a Carlo-
Erba elemental analyzer (Model 1106) or an Elementar Vario
EL. Melting points were obtained in sealed glass capillaries
under N2 and are uncorrected.
(4.22 g, 12.8 mmol) in 120 mL of toluene was heated at reflux
for 140 h. The reaction mixture was filtered, and the solid
was washed with two 10 mL portions of toluene. After removal
of the solvent under high vacuum, sublimation (140 °C, 10-3
Torr) gave pure, crystalline 2b (3.25 g, 76%). Single crystals
suitable for X-ray diffraction were obtained from Et2O at -20
°C (mp 147-149 °C). Anal. Calcd for C18H24AlN5 (337.41):
C, 64.08; H, 7.17; N, 20.76. Found: C, 64.14; H, 7.39; N, 21.50.
MS: m/z 337 (M+, 2), 322 (M+ - CH3, 13), 295 (M+ - N3, 27),
203 (M+ - C9H12N, 21), 135 (C9H13N+, 57), 134 (C9H12N+, 47),
91 (C7H7+, 69), 58 (C3H8N+, 100). 1H NMR (C6D6): δ 2.04 (s,
broad, 6H, N(CH3)(CH3)), 2.23 (s, broad, 6H, N(CH3)(CH3)),
3.26 (s, broad, 2H, CHH), 3.65 (s, broad, 2H, CHH), 6.91 (m,
2H, 3-H), 7.20 (m, 4H, 4,5-H), 7.63 (m, 2H, 6-H). 13C{1H} NMR
(C6D6): δ 45.18 (broad, NCH3), 46.05 (broad, NCH3), 66.63
(CH2), 125.90 (CH), 126.05 (CH), 127.65 (CH), 138.31 (C-6),
147.07 (C-2), 147.4 (broad, C-ipso). 27Al NMR (C6D6): δ 87 (h1/2
) 4400 Hz). IR (toluene; νas(N3), cm-1): 2124.
Ch lor obis[3-(d im eth yla m in o)p r op yl]a lu m in u m (1a ).
17
A suspension, prepared with Li(CH2)3NMe2 (9.31 g, 100.0
mmol) in 200 mL of Et2O, was added dropwise to a solution of
AlCl3 (6.66 g, 49.9 mmol) in 200 mL of Et2O at -78 °C. The
dry-ice bath was removed, and the reaction mixture was
stirred overnight. The solution was filtered, and after removal
of volatiles at ambient temperature, 1a crystallized as large,
colorless needles (9.81 g, 84%, mp 54 °C). Anal. Calcd for
C
10H24AlClN2 (234.75): C, 51.17; H, 10.31; N, 11.93; Al, 11.49.
Found: C, 49.21; H, 9.80; N, 11.53; Al, 11.86. HRMS: m/z
calcd for C10H24Al35ClN2 234.1444, found 234,1476. MS: m/z
234 (M+, 4), 199 (M+ - Cl, 6), 148 (M+ - C5H12N, 72). 1H NMR
(toluene-d8, 293 K): δ 0.13 (m, 4H, AlCH2), 1.46 (m, 2H,
-CHH-), 1.72 (m, 4H, NCHH, -CHH-), 1.95 (s, broad, 12H,
NCH3), 2.71 (m, 2H, NCHH). 13C{1H} NMR (toluene-d8): δ
1.69 (broad, AlCH2), 20.85 (AlCH2CH2), 44.98 (broad, NCH3),
60.92 (NCH2). 27Al NMR (toluene-d8): δ 118 (h1/2 ) 1750 Hz).
Azid ob is[3-(d im et h yla m in o)p r op yl]a lu m in u m (1b ).
Meth od A. A solution of 1a (5.00 g, 21.3 mmol) in 100 mL of
toluene and 50 mL of THF were added to NaN3 (2.76 g, 42.5
mmol), and the mixture was heated at reflux for 15 h. After
removal of the solvent under vacuum, the residue was purified
by sublimation (100 °C, 10-4 Torr) with a -15 °C cold finger.
1b was obtained as small, colorless crystals (4.72 g, 92%).
Meth od B. A mixture of NaN3 (3.16 g, 48.6 mmol) and 1c
(1.36 g, 4.9 mmol) in 40 mL of toluene was heated at reflux
for 64 h. The reaction mixture was filtered, and the solid was
washed with two 10 mL portions of toluene. After removal of
the solvent under high vacuum, trap-to-trap distillation (60-
70 °C, 10-3 Torr) gave pure 1b as a colorless liquid (0.94 g,
80%), which slowly solidified on storage at -15 °C. Anal. Calcd
for C10H24AlN5 (241.31): C, 49.77; H, 10.03; N, 29.02; Al, 11.18.
Found: C, 48.19; H, 10.08; N, 29.26; Al, 11.05. HRMS: m/z
calcd for C10H24AlN5 241.1847, found 241,1848. MS: m/z 241
t er t -Bu t ylch lor o[3-(d im e t h yla m in o)p r op yl]a lu m i-
n u m (3a ). A 1.7 M solution of t-BuLi in pentane (13.0 mL,
22.1 mmol) was added to [Me2N(CH2)3]AlCl2 (4.06 g, 22.1
mmol) dissolved in 120 mL of Et2O at -78 °C. The dry-ice
bath was removed, and the solution was stirred overnight.
Subsequently, volatiles were distilled under high vacuum at
ambient temperature. The residue was extracted with hexane
(60 mL). The solution was filtered, and the solid was washed
with two 10 mL portions of hexane. After removal of the
solvent from the extracts under high vacuum, trap-to-trap
distillation (70-80 °C, 10-3 Torr) yielded 3a (3.81 g, 81%) as
a colorless liquid. Further purification was effected by short-
path distillation (60 mm Vigreux, bp 42-45 °C, 10-3 Torr) (3.11
g, 66%). HRMS: m/z calcd for C9H21AlClN 205.1178, found
205.1179. MS: m/z 205 (M+, 1), 170 (M+ - Cl, 5), 148 (M+
-
C4H9, 100), 58 (C3H8N+, 92). 1H NMR (C6D6): δ 0.21 (m, 2H,
AlCH2), 1.14 (s, 9H, C(CH3)3), 1.30 (m, 1H, AlCH2CHH), 1.53
(m, 1H, NCHH), 1.70 (s, 3H, NCH3), 1.73 (m, 1H, AlCH2CHH),
1.99 (s, 3H, NCH3), 2.18 (m, 1H, NCHH). 13C{1H} NMR (C6D6):
δ 0.40 (broad, AlCH2), 20.66 (AlCH2CH2), 29.63 (C(CH3)3),
43.43 (NCH3), 46.43 (NCH3), 63.70 (NCH2). 27Al NMR (C6D6):
δ 158 (h1/2 ) 1700 Hz).
Azid o -t er t -b u t y l[3-(d im e t h y la m in o )p r o p y l]a lu m i-
n u m (3b). A mixture of NaN3 (7.60 g, 116.9 mmol) and 3a
(2.41 g, 11.7 mmol) in 100 mL of toluene was heated at reflux
for 88 h. The reaction mixture was filtered, and the solid was
washed with two 10 mL portions of toluene. After removal of
the solvent under high vacuum, trap-to-trap distillation (75-
85 °C, 10-3 Torr) gave pure 3b as a colorless liquid (1.39 g,
56%). Anal. Calcd for C9H21AlN4 (212.28): C, 50.92; H, 9.97;
N, 26.39. Found: C, 51.29; H, 10.55; N, 26.97. HRMS: m/z
calcd for C9H21AlN4 212.1582, found 212.1583. MS: m/z 212
(M+, 1), 170 (M+ - N3, 3), 155 (M+ - C4H9, 100), 58 (C3H8N+,
22). 1H NMR (C6D6): δ 0.02 (m, 1H, AlCHH), 0.10 (m, 1H,
AlCHH), 1.09 (s, 9H, C(CH3)3), 1.19 (m, 1H, AlCH2CHH), 1.43
(m, 1H, NCHH), 1.53 (s, broad, 3H, NCH3), 1.58 (m, 1H, AlCH2-
CHH), 1.79 (s, broad, 3H, NCH3), 1.93 (m, 1H, NCHH). 13C-
{1H} NMR (C6D6): δ -1.89 (broad, AlCH2), 20.77 (AlCH2CH2),
29.49 (C(CH3)3), 43.14 (NCH3), 45.50 (NCH3), 63.92 (NCH2).
27Al NMR (C6D6): δ 145 (h1/2 ) 1850 Hz). IR (toluene; νas(N3),
cm-1): 2125.
Azid o-ter t-b u t yl{2-[(d im et h yla m in o)m et h yl]p h en yl}-
a lu m in u m (4b). A mixture of NaN3 (14.08 g, 216.6 mmol)
and 4a (5.75 g, 22.7 mmol) in 150 mL of toluene was heated
at reflux for 90 h. The reaction mixture was filtered, and the
solid was washed with two 10 mL portions of toluene. After
removal of the solvent under high vacuum, trap-to-trap
distillation (110-120 °C, 10-3 Torr) gave pure 4b as a colorless
liquid (4.99 g, 85%). The compound crystallized slowly at room
temperature (mp 38-41 °C). Anal. Calcd for C13H21AlN4
(260.32): C, 59.98; H, 8.13; N, 21.52. Found: C, 59.20; H, 8.40;
N, 22.07. HRMS: m/z calcd for M+ - C4H9 (C9H12AlN4)
203.0877, found 203.0879. MS: m/z 203 (M+ - C4H9, 33), 135
(M+, 7), 199 (M+ - N3, 32), 155 (M+ - C5H12N, 100), 113 (C5H12
-
AlN+, 9). 1H NMR (C6D6): δ -0.15 (m, 2H, AlCHH), -0.05
(m, 2H, AlCHH), 1.38 (m, 2H, AlCH2CHH), 1.60 (s, broad, 6H,
N(CH3)(CH3)), 1.67 (m, 2H, NCHH), 1.73 (m, 2H, AlCH2CHH),
2.05 (s, broad, 6H, N(CH3)(CH3)), 2.38 (m, 2H, NCHH). 13C-
{1H} NMR (C6D6): δ 0.25 (broad, AlCH2), 20.99 (AlCH2CH2),
43.46 (broad, N(CH3)(CH3)), 45.51 (broad, N(CH3)(CH3)), 61.73
(NCH2). 27Al NMR (C6D6): δ 109 (h1/2 ) 1550 Hz). IR (toluene;
νas(N3), cm-1): 2113.
Br om obis[3-(dim eth ylam in o)pr opyl]alu m in u m (1c). Li-
(CH2)3NMe2 (2.48 g, 26.6 mmol) was added to a solution of
AlBr3 (3.55 g, 13.3 mmol) in 50 mL of toluene at -78 °C. The
dry-ice bath was removed, and the reaction mixture was
stirred overnight and subsequently filtered. The solid was
washed with two 10 mL portions of toluene. After removal of
volatiles at ambient temperature, sublimation (60 °C, 10-3
Torr) gave pure 1c (3.02 g, 81%, mp 82-84 °C). Anal. Calcd
for
Found: C, 42.95; H, 8.72; N, 10.60. HRMS: m/z calcd for
10H24AlBrN2 278.0938, found 278.0938. MS: m/z 278 (M+,
C10H24AlBrN2 (279.20): C, 43.02; H, 8.67; N, 10.03.
C
5), 263 (M+ - CH3, 3), 235 (M+ - C3H7, 31), 199 (M+ - Br,
25), 192 (M+ - C5H12N, 100), 87 (C5H13N+, 16), 86 (C5H12N+,
17). 1H NMR (C6D6): δ 0.09 (m, 2H, AlCHH), 0.20 (m, 2H,
AlCHH), 1.45 (m, 2H, AlCH2CHH), 1.65 (m, 2H, NCHH), 1.77
(m, 2H, AlCH2CHH), 1.95 (s, broad, 12H, NCH3), 2.88 (m, 2H,
NCHH). 13C{1H} NMR (C6D6): δ 1.89 (broad, AlCH2), 20.56
(AlCH2CH2), 44.99 (broad, NCH3), 60.47 (NCH2). 27Al NMR
(C6D6): δ 118 (h1/2 ) 1750 Hz).
Azid ob is{2-[(d im et h yla m in o)m et h yl]p h en yl}a lu m i-
n u m (2b). A mixture of NaN3 (8.47 g, 130.3 mmol) and 2a