A Disilane with a Hypercoordinate Silicon Atom:  Coordination of an Imine Ligand versus Si−Si Bond Splitting

Abstract

An imine-amine-substituted disilane (NN)MeSi-SiMe(ONO) [(NN) ≡ PhN(CH 2 ) 2 NPh; (ONO) ≡ o-O-p-MeO-C 6 H 3 -C(Ph)dN-C 6 H 4 -o-O] involving a penta-as well as a tetracoordinate silicon atom was synthesized. This ligand combination gives rise to a stable disilane with a hypercoordinate silicon atom by the imine donor action, while a 1,1-dichlorosilane (MeCl 2 Si)-SiMe(ONO) is not available due to Si-Si bond cleavage with formation of the pentacoordinate monosilane SiClMe(ONO).

Novel hexacoordinate organosilicon(IV) complexes of diethylenetriamine Schiff base with SiO2N3 skeleton

“…Wagler and co-workers [6][7][8][9][10] synthesized a large number of hypercoordinated complexes of silicon by using different salen and salphen type ligands and studied their reactivity. Recently, Bohme and his co-workers 11 also reported a new application of Wagler elimination by synthesizing a macrocyclic silicon enamine derivative.…”

Silicon(IV) Chelates of an (ONN')-Tridentate Pyrrole-2-Carbaldimine Ligand: Syntheses, Structures and UV/Vis Properties

“…This MO-based analysis which is in sharp contrast to the interpretation advocated by Pettinari that separates the π-π * transition of the imine-linked conjugated system (band 2) from the π-π * transition of the benzenoid system (band 1) may therefore also be applicable to the N-(o-oxyphenyl)imine-containing Sn complexes [13] and the Si-salop complexes [14].…”

“…That the red shift of band 1 is related to the planarity of the ligand was earlier demonstrated by one of us for salop silicon complexes. For example, structure A (R, R = Me, Silyl) in Scheme 8 has a planar ONO -ligand and absorbs at 464 nm, while B (R, R = Ph, Ph) with a twisted ligand absorbs at 386 nm [14]. Although the planarity of the ONN -ligand would suggest an influence of the pyrrole ring on the extended π system and hence on the optical properties of LSiRR , its definite role remains unclear.…”

Synthetic methods : Part (iii) Heteroatom chemistry

“…Wagler reported the synthesis of disilane 38 containing a tetra-and pentacoordinate silicon atom, the latter of which are important species in electron-transfer processes, particularly for non-linear optic materials. 73 Wagler reacted disilane 37 with a tridentate ligand (Scheme 28) to give product 38. The new silicon-silicon bond in 38 was not thought to be weakened significantly.…”