| Abstract
| - The reaction of (ClCH2)2SiCl2 (4) with O-Me3Si-hydrazides (3) yields three new types of products: a1:2 reagent ratio leads to a neutral hexacoordinate dichelate with two six-membered rings each containingan N+−N- ylide structure, as well as to the corresponding dissociated pentacoordinate dichelate siliconiumchloride salt. These products readily undergo partial hydrolysis to form a dinuclear complex: dicationicdisiloxane dichloride. All three product types have been characterized by means of single-crystal structureanalysis. Nonempirical ab initio calculations were carried out to determine the atomic charges. Naturalbond order (NBO) calculations show that there are no significant charge accumulations on either theammonium or the imidate nitrogen in the ylide moieties and that the net charge on silicon (which couldformally be −2) is between +1.8 and +2.1 e in all species, regardless of overall molecular charge.
- The synthesis, crystal structure, and properties of neutral hexacoordinate and ionic pentacoordinate silicon dichelates, and their disiloxane dinuclear derivatives, with six-membered chelate cycles containing an N+−N- ylide structure are reported. Ab initio calculations show that charge distribution on atoms is governed primarily by atom electronegativities rather than formal charges.
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