Neue Hypersilanide der Erdmetalle Aluminium, Gallium und Indium

Ditrielanes (R3Si)2E−E(SiR3)2 and Heterocubanes (R3Si)4E4Y4 (R3Si =tBu3Si,tBu2PhSi; E = Al, Ga, In, Tl; Y = O, Se)

“…Table 1). Interestingly, in ditrielanes R 4 E 2 with sterically less overcrowded silyl substituents the angles between the EER 2 planes decrease with decreasing bulkiness of R and are 79.9°for 5 and 82.2°for 6, according to Figure 3 and Table 1 {for comparison [(Me 3 Si) 3 Si] 4 E 2 : 80°(Ga) [9] /78.6°( In) [10] /78.1°(Tl)}. [11] Significant smaller angles between the EER 2 planes show the organylditrielanes Tip 4 E 2 and Ϫ above all Ϫ Dsi 4 E 2 [for E ϭ Al/Ga/In in Tip 4 E 2 with Tip ϭ 2,4,6-iPr 3 C 6 H 2 45/44/48°and in Dsi 4 E 2 with Dsi ϭ (Me 3 Si) 2 CH 8/5/7°; cf.…”

“…The space-filling properties of the groups R* and RЈ lead to unusually long EϪE distances in 1 (2.75 Å ), 3 (2.93 Å ), 5 (2.94 Å ), 4 (2.96 Å ) and 6 (2.88 Å ). [10] This means that the steric hindrance increases on going from 1 to 2 with the consequence that 2 is much more unstable with respect to elimination of R* than the dialane. radius in the direction Al Ǟ Ga because of a d-orbital contraction which only effects r Ga , but not r Al .…”

“…The λ max value of the visible absorption shifts with increasing atomic number of E and with the increasing angle between the R 2 EE planes to longer wavelengths (ruby R− besides the mentioned ditrielanes − are presented.In fact, except for the compounds dealt with in this publication, only three other examples of silyl-ditrielanes, namely [(Me 3 Si) 3 Si] 4 E 2 with E ϭ Ga, [9] In, [10] Tl [11] have been published to date. According to X-ray structure analyses, the ditrielanes contain two planar groups R 2 EE which are orthogonal to each other (R = R*; angle REER ca.…”

“…In fact, except for the compounds dealt with in this publication, only three other examples of silyl-ditrielanes, namely [(Me 3 Si) 3 Si] 4 E 2 with E ϭ Ga, [9] In, [10] Tl [11] have been published to date. On the other hand, some organyland aminyl-ditrielanes R 4 E 2 are known with R ϭ…”

Die Kristallstruktur von Diethylaluminiumhypersilanid, [(C2H5)2Al-Si{Si(CH3)3}3]2

“…Unla È ngst berichteten wir u È ber die Darstellung der einfachen Dialkylaluminiumhypersilanide [R 2 Al±Hsi] 2 (mit R = Me, Et und Hsi = ±Si(SiMe 3 ) 3 ) aus den entsprechenden Dialkylaluminiumchloriden und a È quimolaren Mengen an basefreiem Li±Hsi in n-Pentan [1]. Wa È hrend die Methylverbindung in Lo È sung und im Kristall dimer vorliegt und zu den seltenen, u È ber Methylgruppen verbru È ckten Organoaluminiumderivaten za È hlt, ist das erheblich niedriger schmelzende Ethylhomologe in verdu È nnter Lo È sung monomer, was bereits die ausbleibende Signalaufspaltung der bei tiefen Temperaturen (bis ca.…”