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 degrees C. The reaction of 1 with LiAlH4 in diethyl ether solution at -78 degrees 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 degrees 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 degrees C. The homoleptic derivative Ar'3Al (8) was obtained when 3 equiv of Ar'Li was employed. Crystal data for 1: monoclinic, space group P2(1), a = 6.534(1) A, b = 10.801(1) A, c = 9.631(2) A, beta = 105.57(2) degrees, V = 654.8(2) A3, Z = 2, R = 0.0453. Crystal data for 2: monoclinic, space group P2(1), a = 6.552(2) A, b = 10.833(2) A, c = 9.601(2) A, beta = 106.05(2) degrees, V = 654.9(3) A3, Z = 2, R = 0.0609. Crystal data for 3: monoclinic, space group P2(1)/c, a = 7.401(2) A, b = 15.746 A, c = 10.801(4) A, beta = 92.37(3) degrees, V = 1257.6(7) A3, Z = 2, R = 0.0712. Crystal data for 4: monoclinic, space group P2(1)/c, a = 13.343(2) A, b = 11.228(2) A, c = 7.505(1) A, beta = 100.64(1) degrees, V = 1105.0(4) A3, Z = 4, R = 0.0560.

Synthesis of Linear Acetylenic Carbon: The "sp" Carbon Allotrope.

A carbon allotrope based on "sp" hybridization containing alternating triple and single bonds (an acetylenic or linear carbon allotrope) has been prepared. Studies of small (8 to 28 carbon atoms) acetylenic carbon model compounds show that such species are quite stable (130 degrees to 140 degrees C) provided that nonreactive terminal groups or end caps (such as tert-butyl or trifluoromethyl) are present to stabilize these molecules against further reactions. In the presence of end capping groups, laser-based synthetic techniques similar to those normally used to generate fullerenes, produce thermally stable acetylenic carbon species capped with trifluoromethyl or nitrile groups with chain lengths in excess of 300 carbon atoms. Under these conditions, only a negligible quantity of fullerenes is produced. Acetylenic carbon compounds are not particularly moisture or oxygen sensitive but are moderately light sensitive.