Tetrasupersilyldiindium(In–In) and Tetrasupersilyldithallium(TlTl): (tBu₃Si)₂MM(SitBu₃)₂ (M = In, Tl)

Abstract

Deep violet (tBu3Si)4In2 (1) and black‐green (tBu3Si)4Tl2 (2) are formed from MBr and tBu3SiNa in THF at −78 °C [Eq. (a)]. The M atoms of 1 (decomp. 125 °C) and 2 (decomp. 52 °C) are each coordinated by two Si atoms and one M atom in a trigonal‐planar fashion, and the two Si2MM planes are orthogonal.

Hexasupersilyloctaindane (tBu3Si)6In8— A Compound with a Novel In8 Cluster Framework

“…The compound R* 6 In 8 (3) is after R* 8 In 12 (2) a further rare cluster structure for boron and its homologues. In accord with the structural formula shown for 2, the dodecaindane, which can be described as conjuncto-indane, consists of two R* 4 In 6 clusters with distorted In 6 octahedral frameworks. Unfortunately, an In 6 cluster of this type has not yet been isolated as a solid.…”

“…2.65 ) correspond to those in 2 (av 2.68 [1] ). They are shorter than those in the diindane R* 4 In 2 (ca. 2.78 [4] ), which is consistent with a significantly reduced steric interaction between the supersilyl groups in 3.…”

“…After two days the resulting dark green solution was allowed to warm to room temperature, and from this solution we obtainedÐafter replacement of the solvent pentane by benzeneÐblack-green crystals, which, according to X-ray structure analysis, [2] were again not tetrahedrane molecules 1 c, but hexasupersilyloctaindane molecules 3. The latter are formed together with diindane R* 4 In 2 , which is consistent with a reaction such as that given in Equation (1). Compound 3 is comparatively sensitive to oxidation and hydrolysis.…”

“…111.58) lie in the normal ranges of 1.94 ± 1.95 and 110 ± 1128, [5] respectively (cf. R* 4 In 2 : 1.95 , 109.78 [4] ). Figure 1 also reveals that the eight In atoms in 3 form a cube stretched along one body diagonal (local symmetry of the In 8 cluster: C i ; see Table 1 for details with regard to the lengths of the four body diagonals of the cluster) and the six supersilyl groups form a distorted octahedron.…”

“…We recently reported [1] that tetrasupersilyldialane R* 4 Al 2 and trisupersilyldigallanyl R* 3 Ga 2 (a secondary product of the digallane R* 4 Ga 2 which is metastable at room temperature) are converted in heptane at 100 8C into tetrasupersilyltetrahedro-tetraalane (1 a) and -tetragallane (1 b), respectively, whereas the thermolysis of tetrasupersilyldiindane R* 4 In 2 in heptane at 100 8C did not afford the analogous tetraindane 1 c, but the octasupersilyldodecaindane 2 (R* supersilyl tritert-butylsilyl).…”