title: Pyramidanes.
abstract: Pyramidane is an elusive but highly desirable target for synthetic chemists that has attracted a great deal of attention because of its nonclassical structure and unusual bonding features. Although well studied on theoretical grounds, neither the parent all-carbon pyramidane nor its derivatives containing heavier group 14 elements have ever been isolated and characterized. In this Communication, we report on the synthesis and structural elucidation of the first stable representatives of this class of highly strained polyhedral compounds: germa- and stannapyramidanes Ge[C4(SiMe3)4] and Sn[C4(SiMe3)4]. The peculiar structural and bonding features of these compounds are verified by combined experimental and computational analyses, showing these derivatives to be nonclassical neutral compounds with a very large contribution of ionic character.
authors.affiliation: Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan. leevya@chem.tsukuba.ac.jp
authors.forename: Vladimir Ya
authors.initials: VY
authors.lastname: Lee
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ito
authors.forename: Akira
authors.initials: A
authors.lastname: Sekiguchi
authors.forename: Heinz
authors.initials: H
authors.lastname: Gornitzka
authors.forename: Olga A
authors.initials: OA
authors.lastname: Gapurenko
authors.forename: Vladimir I
authors.initials: VI
authors.lastname: Minkin
authors.forename: Ruslan M
authors.initials: RM
authors.lastname: Minyaev