Synthesis and Characterization of 8-(Dimethylamino)-1-naphthyl Derivatives of Aluminum, Gallium, and Indium

The group 13 dichlorides of formula Ar‘MCl2 [Ar‘ = 8-(dimethylamino)-1-naphthyl (8-(Me2N)C10H6)], M = Al
(1), Ga (2), and In (3), have been prepared via the salt elimination reaction of 1 equiv of Ar‘Li with MCl3 in
toluene solution at −78 °C. The reaction of 1 with LiAlH4 in diethyl ether solution at −78 °C produced the
dihydride [Ar‘AlH2]2 (4). The X-ray crystal structures of 1−4 have been determined and show that 1 and 2 are
monomeric while 3 and 4 are dimeric in the solid state. The reaction of 1 with RLi in toluene solution at −78 °C
results in ligand redistribution and formation of Ar‘2AlR (R = Me (5), t-Bu (6)). The chloride analogue of 5 and
6, Ar‘2AlCl (7), can be prepared directly from the reaction of 2 equiv of Ar‘Li with AlCl3 in toluene solution at
−78 °C. The homoleptic derivative Ar‘3Al (8) was obtained when 3 equiv of Ar‘Li was employed. Crystal data
for 1:  monoclinic, space group P21, a = 6.534(1) Å, b = 10.801(1) Å, c = 9.631(2) Å, β = 105.57(2)°, V =
654.8(2) Å3, Z = 2, R = 0.0453. Crystal data for 2: monoclinic, space group P21, a = 6.552(2) Å, b = 10.833(2)
Å, c = 9.601(2) Å, β = 106.05(2)°, V = 654.9(3) Å3, Z = 2, R = 0.0609. Crystal data for 3:  monoclinic, space
group P21/c, a = 7.401(2) Å, b = 15.746 Å, c = 10.801(4) Å, β = 92.37(3)°, V = 1257.6(7) Å3, Z = 2, R =
0.0712. Crystal data for 4:  monoclinic, space group P21/c, a = 13.343(2) Å, b = 11.228(2) Å, c = 7.505(1) Å,
β = 100.64(1)°, V = 1105.0(4) Å3, Z = 4, R = 0.0560.