Luo and Gladfelter
0.37 (6H, t, CH3), 1.02 (4H, m, CH2CH2CH3), 1.86 (2H, t, NH),
2.80 (4H, m, CH2CH2CH3). The multiplets at δ 7.35, 7.70, 7.79,
and 7.93 for the aromatic hydrogens and at δ 1.02 for CH2CH2-
CH3 were not distinguished between the two isomers. The trans/
cis isomer molar ratio was 2:1. IR (cm-1): νNH, 3300, 3294, and
3275. CI MS [assignment, % relative intensity]: 582 [(M + NH3
+ H)+, 1.4], 565 [(M + H)+, 17.1], 523 [(M - NHnPr + NH3)+,
2.1], 504 [(M - Ph + NH3)+, 100], 487 [(M - Ph)+, 20.6], 462
[{Ph3Ga2(NHnPr)(NH2)(NH3)}+, 1.6], 426 [{Ph2Ga2(NHnPr)2-
(NH3), 2.6], 69 [Ga+, 0.2]. Anal. Calcd for C36H32Ga2N2: C, 45.48;
H, 9.69; N, 8.16. Found: C, 43.40; H, 9.61; N, 7.70.
Synthesis of (PhGaNMe)7 (6). Method 1. A slurry of compound
1 (1.80 g, 3.54 mmol) in 10 mL of dodecane (bp, 216 °C) was
heated in an oil bath. A colorless solution formed at approximately
130 °C, and heating was continued to reflux (220 °C) for 6 h. When
the solution was cooled to room temperature, a white solid
precipitated. The slurry was stored at 0 °C overnight to induce
additional precipitation. The precipitate was separated by a filtration
and dissolved in toluene (10 mL). After the toluene solution was
stored at -20 °C for 5 days, small blocks formed and were isolated.
These crystals consisted of compound 6 and toluene molecules and
were suitable for the single-crystal X-ray diffraction analysis. The
solvent-free sample of compound 6 (0.30 g, 24% yield) was
obtained as a white powder after the crystals were heated at 100
°C for 0.5 h under vacuum. Mp: 288-290 °C; a glassy solid was
obtained when the melted sample was cooled, which remelted at
n
(NH2)}+, 1.5], 299 [{Ph2Ga(NH2 Pr)(NH3)}+, 0.6], 257 [{Ph2Ga-
(NH3)2}+, 2.0], 240 [{Ph2Ga(NH3)}+, 1.1], 223 [(Ph2Ga)+, 0.7],
69 [Ga+, 0.7]. Anal. Calcd for C30H36Ga2N2: C, 63.88; H, 6.43;
N, 4.97. Found: C, 63.76; H, 6.72; N, 4.99.
Synthesis of [Ph2GaN(H)iBu]2 (4). To a slurry of Ph3Ga (3.42
g, 11.4 mmol) in Et2O (30 mL) at room temperature was added
i
1.20 mL of BuNH2 (0.871 g, 11.9 mmol). A colorless solution
was obtained immediately. After it was stirred for 0.5 h, volatiles
were removed under vacuum leaving a colorless crystalline solid.
The solid was heated in an oil bath and melted at around 115 °C.
Benzene elimination was observed at the temperatures above 130
°C, and the reaction was allowed to proceed at 150 °C for 1 h to
afford a white solid. After it was recrystallized from ether (20 mL)
at -20 °C, a colorless crystalline solid was isolated (2.64 g, 79%
1
260-270 °C. H NMR: δ 2.96 (9H, s, CH3), 3.18 (9H, s, CH3),
3.60 (3H, s, CH3), 7.24, 7.68 and 7.83 (35H, m, Ph). IR (cm-1; s,
strong; m, medium; w, weak): 3063 m, 3047 m, 3010 w, 3001 w,
2990 w, 2929 m, 2900 m, 2871 s, 2800 s, 1483 w, 1459 m, 1426
s, 1254 w, 1098 m, 1086 s, 1080 s, 1031 s, 998 w, 964 s, 728 s,
701 s, 679 s, 664 s. CI MS [assignment, % relative intensity]: 1232
[(M + H)+, 14], 1171 [(M - Ph + NH3)+, 1.5], 1154 [(M - Ph)+,
7.4], 78 [C6H6+, 100]. Anal. Calcd for C49H56Ga7N7: C, 47.81; H,
4.58; N, 7.96. Found: C, 48.06; H, 4.68; N, 7.59.
1
yield). Mp: 162.5-164.5 °C. H NMR for the trans isomer: δ
0.44 (12H, d, CH3), 1.34 (2H, m, CH), 2.48 (2H, t, NH), 2.60 (4H,
1
t, CH2). H NMR for the cis isomer: 0.45 (12H, d, CH3), 1.34
(2H, m, CH), 2.19 (2H, t, NH), 2.82 (4H, t, CH2). The multiplets
at δ 7.26, 7.35, 7.78, 7.85, and 7.98 for the aromatic hydrogens
and at δ 1.34 for CH were not distinguished between the two
Method 2. Neat compound 1 (2.00 g, 3.94 mmol) was heated in
an oil bath at 220 °C for 4 h. Benzene elimination was observed at
temperatures above 200 °C. After benzene was removed under
vacuum, a white, glassy solid remained. 1H NMR spectrum of the
solid indicated that it contained ∼20% compound 6 by comparing
the -NMe resonances. Pure, solvent-free compound 6 (0.12 g, 8.7%
yield) was isolated after the crude products were recrystallized twice
in toluene and solvent was removed from the crystals upon heating
under vacuum.
isomers. The trans/cis isomer molar ratio was 2:1. IR (cm-1): νNH
,
3302, and 3280. CI MS (assignment, % relative intensity): 593
[(M + H)+, 15.2], 537 [(M - NHiBu + NH3)+, 4.1], 532 [(M -
Ph + NH3)+, 100], 515 [(M - Ph)+, 18.7], 476 [{Ph3Ga2(NHiBu)-
(NH2)(NH3)}+, 1.0], 454 [{Ph2Ga2(NHiBu)2(NH2)}+, 1.1], 313
[{Ph2Ga(NH2 Bu)(NH3)}+, 0.6], 257 [{Ph2Ga(NH3)2}+, 1.6], 240
i
[{Ph2Ga(NH3)}+, 0.7], 223 [(Ph2Ga)+, 0.6], 69 [Ga+, 0.4]. Anal.
Calcd for C32H40Ga2N2: C, 64.91; H, 6.81; N, 4.73. Found: C,
64.54; H, 6.82; N, 4.69.
Synthesis of (PhGaNPh)4 (7). Compound 5 (0.930 g, 1.47
mmol) was heated at 180 °C for 2 h. During this process, benzene
formed and was removed under vacuum to afford a white solid.
Colorless plates were isolated when the solid was recrystallized in
benzene (30 mL) at 0 °C, and a solvent-free sample of compound
7 (0.39 g, 55% yield) was obtained as a white powder after benzene
was removed under vacuum. Mp: 230 °C, decomp without melting.
1H NMR: δ 6.71, 6.89, 7.02, 7.15, 7.29 and 7.37 (all m, Ph). IR
(cm-1; s, strong; m, medium; w, weak): 3067 m, 3048 w, 3017 m,
2993 w, 1588 s, 1485 s, 1447 w, 1429 m, 1224 s, 1177 w, 1154 w,
1088 m, 1077 m, 1028 m, 998 m, 892 w, 859 m, 822 w, 769 s,
733 m, 695 s, 673 m. CI MS [assignment, % relative intensity]:
970 [(M + NH4)+, 0.7], 953 [(M + H)+, 2.4], 875 [(M - Ph)+,
trace], 94 [C6H5NH3+, 100]. Anal. Calcd for C48H40Ga4N4: C,
60.57; H, 4.24; N, 5.89. Found: C, 59.67; H, 4.77; N, 5.56.
X-ray Data Collection, Structure Solution, and Refinement.
Suitable crystals of compounds 6 and 7 were mounted on top of
glass fibers under a cooled nitrogen flow. Both data collections
were conducted on a Siemens SMART system. In each experiment,
an initial set of cell constants was calculated from reflections
harvested from three sets of 20 frames. These sets of frames were
oriented such that orthogonal wedges of reciprocal space were
surveyed. A randomly oriented region of reciprocal space was
surveyed to the extent of 1.3 hemispheres to a resolution of 0.84
Å. Three major swaths of frames were collected with 0.30° steps
in ω. The data collection technique was generally known as a
hemisphere collection. However, in the experiment for compound
6, around 20% of the reflections were not indexed. Twinning was
Synthesis of Ph3Ga(NH2Ph). To a solution of Ph3Ga (3.00 g,
9.97 mmol) in toluene (10 mL) at room temperature was added
0.91 mL of PhNH2 (0.93 g, 10 mmol). The colorless solution was
stirred for 0.5 h. The solution was stored at -20 °C overnight to
afford colorless blocks (3.3 g, 83% yield). Mp: 100 °C, decomp
1
without melting. H NMR: δ 3.34 (2H, s, NH2), 6.02 and 6.67
(5H, m, NPh), 7.31 and 7.67 (15H, m, GaPh3). IR (cm-1): νNH
,
3309 and 3254. CI MS [assignment, % relative intensity]: 371
[(Ph3Ga2)+, 100], 316 [(Ph2GaNHPh + H)+, 15.7], 223 [(Ph2Ga)+,
80.5], 93 [(C6H5NH2)+, 77.2].
Synthesis of [Ph2GaN(H)Ph]2 (5). Neat Ph3Ga(NH2Ph) (1.30
g, 3.30 mmol) was heated in an oil bath at 110 °C for 2 h. Benzene
was eliminated and removed under vacuum affording a white solid.
After it was recrystallized in toluene (5 mL) at -20 °C, small
colorless blocks were collected (0.93 g, 89% yield). Mp: 152 °C,
1
1
decomp. H NMR for the trans isomer: δ 4.91 (2H, s, NH). H
NMR for the cis isomer: 4.58 (2H, s, NH). The multiplets at δ
6.83, 7.16, and 7.50 for the aromatic hydrogens were not distin-
guished between the two isomers. The trans/cis isomer molar ratio
was 2:1. IR (cm-1): νNH, 3284. CI MS [assignment, % relative
intensity]: 633 [(M + H)+, 0.2], 572 [(M - Ph + NH3)+, 2.7],
557 [(M - NHPh + NH3)+, 1.8], 540 [(M - NHPh)+, 0.5], 496
[{Ph3Ga2(NHPh)(NH2)(NH3)}+, 1.0], 333 [{Ph2Ga(NH2Ph)(NH3)}+,
4.0], 316 [(0.5M + H)+, 1.0], 257 [{Ph2Ga(NH3)2}+, 100], 240
[{Ph2Ga(NH3)}+, 10.9], 223 [(Ph2Ga)+, 2.3], 195 [PhGa(NH2)2-
592 Inorganic Chemistry, Vol. 41, No. 3, 2002