Bidentate Ligands Forming Four-Membered Rings with Silicon

3 Bidentate Ligands Forming Four-Membered Rings with Silicon 

Benzamidinates (and guanidinates) are able to stabilize pentacoordinated silicmi complexes. The amidinate ligand coordinates via both nitrogen atoms to the central silicon atom, which is further supplemented by three other anionic ligands as it is shown exemplarily by the compounds 105-110 [200, 252-254]. 

4 Bidentate Ligands Derived from Carboxylic Acids 

Amides and hydrazides of carboxylic acids have been also used successfully by other groups to stabilize penta- and hexacoordinated silicon. The compounds 119 [265], 120 [266], and 79 [206] serve as examples. 

Compound 119 involves a cyclic amide of an ca-amino acid as ligand. Related to this are complexes containing cyclic amides like uracil (121), barbituric acid, 5,5-dimethylbarbituric acid [116], 2,5-piperazinedione (85) [226], and 2-chloro-6-hydroxypyridine (86) [221], respectively, to accomplish pentacoordination at silicon. 

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Bidentate ligands forming four-membered rings with silicon... 

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