Halide‐Ion Diadducts of Perhalogenated Cyclopenta‐ and Cyclohexasilanes

Abstract

The halosilicates(II) [nBu 4 N] 2 [Si 6 Br 12 ·2Br] and [nBu 4 P] 2 [Si 6 I 12 ·2I] were prepared by mere addition of the appropriate halide salt to the corresponding disilane Si 2 X 6 (X = Br, I). In the first case, the Br 3 Si-substituted derivative [nBu 4 N] 2 [Si 7 Br 14 ·2Br] formed as a second product. We have been able to obtain single crystals of [Ph 4 P] 2 [Si 7 Br 14 ·2Br] by switching the Brsalt from [nBu 4 N]Br to [Ph 4 P]Br. All three compounds, [nBu 4 N] 2 [Si 6 Br 12 ·2Br] (monoclinic, P2 1 /c), [nBu 4 P] 2 [Si 6 I 12 ·2I] (triclinic, P1), and [Ph 4 P] 2 [Si 7 Br 14 ·2Br] (triclinic, P1) were structurally characterized by X-ray crystallography and found to form "inverse sandwich complexes", in which two Xions are located above and below a planarized Si 6 ring. The free periodated cyclohexasilane Si 6 I 12 is accessible from [nBu 4 N] 2 [Si 6 Cl 12 ·2Cl] and BI 3 (1:5 molar ratio; CH 2 Cl 2 ) via a decomplexation/halide-exchange cascade. Si 6 I 12 (monoclinic, C2/c) adopts a

Tetrel Bonding Interactions in Perchlorinated Cyclopenta- and Cyclohexatetrelanes: A Combined DFT and CSD Study

“…Of particular interest among the scientific community is perhalogenated cyclohexasilanes, due to its ability to act as a multiple tetrel bond donor using the twelve available σ-holes. In fact, crystallographic studies [ 35 , 36 , 37 ] have shown that perhalogenated cyclohexasilanes can strongly bind electron-rich moieties, such as halide anions or organocyanides (such as acetonitrile). Several theoretical studies [ 38 , 39 , 40 , 41 ] have explored this possibility by theoretically analyzing a series of anion/lone pair-Si inverted sandwiched complexes and confirming their ability to behave as efficient ditopic anion receptors.…”

One-Pot Condensation of a Bicyclo[1.1.1]pentasilane through Elimination of Iodotrimethylsilane Assisted by a Lewis Base

“…Although the fraction with the second longer retention time could be identified as 7 ( n = 3), its further characterization was unsuccessful due to its very low amount and low solubility. The condensation reaction also proceeded in toluene and benzotrifluoride, while the reaction in CD 2 Cl 2 afforded a complex mixture including i -Bu 2 SiCl 2 , indicating that the BPS cage decomposed in this condition. , Notably, DMAP is a suitable Lewis base in the condensation of the BPS: when other Lewis bases such as P t -Bu 3 , PPh 3 , and NEt 3 were used, the reactions in C 6 D 6 did not complete even at 80 °C for 24 h, although the formation of 6 (and 7 ) were observed in 1 H NMR spectra. The observed slower reactions probably emerged from high solubility of the corresponding base–TMSI complexes, which would cause the corresponding reverse reactions.…”

Selective One‐Pot Syntheses of Mixed Silicon‐Germanium Heteroadamantane Clusters

“…Upon going from [2] to [1] and [0] , dichlorosilylenes (SiCl 2 ) are extruded from the cluster cores and dimethylgermylenes (GeMe 2 ) are incorporated. Formal cyclocondensation of 6 SiCl 2 moieties would give perchlorinated cyclohexasilane, which was indeed detected by 29 Si NMR spectroscopy in the form of [ cyclo ‐Si 6 Cl 12 ⋅ 2Cl] 2− [22–26] . The GeMe 2 fragments, in turn, must originate from cannibalized heteroadamantanes [2] and [1] .…”

“…Formal cyclocondensation of 6 SiCl 2 moieties would give perchlorinated cyclohexasilane, which was indeed detected by 29 Si NMR spectroscopy in the form of [ cyclo ‐Si 6 Cl 12 ⋅ 2Cl] 2− . [ 22 , 23 , 24 , 25 , 26 ] The GeMe 2 fragments, in turn, must originate from cannibalized heteroadamantanes [2] and [1] .…”

“…Formal cyclocondensation of 6 SiCl 2 moieties would give perchlorinated cyclohexasilane, which was indeed detected by 29 Si NMR spectroscopy in the form of [cyclo-Si 6 Cl 12 • 2Cl] 2À . [22][23][24][25][26] The GeMe 2 fragments, in turn, must originate from cannibalized heteroadamantanes iii) The reaction critically depends on certain properties peculiar to Ge, because the use of Me 2 SiCl 2 instead of Me 2 GeCl 2 does not lead to the corresponding Si 14 heteroadamantane (Me 2 SiCl 2 rather behaved as an innocent bystander of the Cl Àinduced Si 2 Cl 6 disproportionation [17] ).…”