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Experimental Charge Density Studies of Cyclotetrasilazane and Metal Complexes Containing the Di‐ and Tetraanion
Author(s) -
Kocher Nikolaus,
Selinka Carola,
Leusser Dirk,
Kost Daniel,
Kalikhman Inna,
Stalke Dietmar
Publication year - 2004
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200400277
Subject(s) - covalent bond , ionic bonding , chemistry , lithium (medication) , crystallography , metal , homologous series , polar , stereochemistry , ion , organic chemistry , physics , medicine , astronomy , endocrinology
The homologous series of parent octamethylcyclotetrasilazane ( c ‐NH‐SiMe 2 ‐) 4 , ( 1 ), the lithium complex [(THF) 2 Li 2 ( c ‐N‐SiMe 2 ‐NH‐SiMe 2 ‐) 2 ] 2 , ( 2 ), containing the cyclic dianion, and [(THF) 2 LiAl( c ‐N‐SiMe 2 ‐) 4 ] 2 , ( 3 ), accommodating the unprecedented tetraanion [Me 2 SiN] 4‐ was synthesized to investigate the nature of the covalent Si‐N single bond in the presence of various metals. These model compounds show a wide diversity of Si‐N(H), Si‐N(M), Si‐N(H, M) and M‐N bonds and serve as bench‐mark systems to study polar bonds by high‐resolution low‐temperature X‐ray structure analysis. Experimental charge density studies reveal highly polar Si‐N bonds with remarkable ionic contribution, even in the non‐metallated starting material 1 . The Li‐N and Li‐O bonds have to be classified as almost purely ionic bonds with topological properties not far from those determined for NaCl.