A Threefold AlH₂‐Coordinated Carbon Atom as Part of the First Carbaalanate

Abstract

The first carbaalanate consists of a carbaalane dianion [(AlH)8(CCH2tBu)6]2− that is coordinated through hydride bridges to two lithium ions on opposite sides of the cluster (see picture). Additionally, the lithium ions are each further coordinated to a neutral [tBuCH2C(AlH2⋅NMe3)3] unit. In this arrangement, the lithium ion prevents condensation of the [tBuCH2C(AlH2⋅NMe3)3] units.

Hydroalumination of diazo and azido compounds: An Al-H addition to end-on nitrogen of substrates

“…The initial deprotonation followed by multiple Al-H addition was also observed to form the carbaalane clusters. This has been demonstrated by Roesky [2,10,12] and Uhl [1, 9,13] groups. LAlH 2 reacting with PhCCH, however, stops the products as monodeprotonated LAlH(CCPh) (5) and subsequently double-deprotonated LAl(CCPh) 2 (6) with the increased reaction temperatures (Scheme 5).…”

“…In contrast to the formation of highly aggregated alane clusters using simple aluminum hydrides [8][9][10][11][12][13][14][15][16][17], such lower aggregation products are available when the reactive aluminum hydrides are stabilized by the sterically demanding ligands [19,20]. This may offer a better understanding on the reaction pathways and further the interaction mechanisms.…”

“…It exhibits diverse reactivity patterns with the variation of aluminum hydrides as well as its interacted substrate sources [1][2][3][4][5][6][7], and thus attracts particular interest. The use of AlH 3 ·NMe 3 or dialkylaluminum hydrides as precursors to react with unsaturated molecules, such as alkynes [8][9][10][11][12][13], nitriles, and isonitriles [14][15][16][17], has led to the formation of unique classes of carbaalane, imidoalane, and carbaamidoalane clusters. Several different reaction mechanisms have been suggested and discussed with respect to the highly aggregated forms of the hydroalumination products.…”

Segregation of tetracarbon units in low‐energy tetracarbindane structures: Major differences from their aluminum and gallium analogs

“…However, for gallium the major gallium‐carbon clusters obtained from such reaction of this type are 10‐vertex adamantane‐like tetracarbagallanes R' 4 C 4 Ga 6 R 6 (R and R' = alkyl groups) rather than 11‐vertex clusters similar to the tetracarbalanes (Figure ). Aluminum, but not gallium, has also been shown to form larger clusters with more than four cluster carbon atoms . These include the 13‐vertex pentacarbalane (AlMe) 8 (CCH 2 Ph) 5 (μ 4 ‐H) and the 14‐vertex hexacarbalanes (AlMe) 8 (CCH 2 Ph) 5 (CCPh) and [(AlH) 8 (CCH 2 t Bu) 6 ] 2− .…”

“…Aluminum, but not gallium, has also been shown to form larger clusters with more than four cluster carbon atoms. [6][7][8][9] These include the 13-vertex pentacarbalane (AlMe) 8 (CCH 2 Ph) 5 (μ 4 -H) and the 14-vertex hexacarbalanes (AlMe) 8 (CCH 2 Ph) 5 (C CPh) and [(AlH) 8 (CCH 2 t Bu) 6 ] 2− .The synthesis of these tetracarbalanes and tetracarbagallanes as well as the structural differences of the major products obtained from corresponding reactions of organoaluminum and organogallium derivatives has stimulated theoretical studies on related organometallic clusters containing carbon and group 13 elements. An underlying feature of the low-energy structures of such clusters is the strong energetic preference of carbon vertices to have degrees no greater than four.…”