Three novel pentacoordinate silicon compounds with
SiO
5 skeletons containing SiOH or SiOSi groupswere synthesized: triethylammonium bis[benzilato(2-)-
O1,
O2]hydroxosilicate (
1; isolated as
rac-
1), aniliniumbis[benzilato(2-)-
O1,
O2]hydroxosilicate [
2; isolated as a conglomerate consisting of (
![](/images/entities/Lgr.gif)
)-
2·THF and (
![](/images/gifchars/Delta.gif)
)-
2·THF], and anilinium tetrakis[benzilato(2-)-
O1,
O2]-
![](/images/entities/mgr.gif)
-oxo-disilicate (
3; isolated as
rac-
3·2CH
3CN). The
5Si-hydroxosilicate and
5Si,
5Si'-
![](/images/entities/mgr.gif)
-oxo-disilicate anions of these salts formally derive from the pentahydroxosilicate(1-) anion [Si(OH)
5]
- and its anhydride [(HO)
4Si-O-Si(OH)
4]
2-, respectively. All compounds werecharacterized in solution (
1H,
13C, and
29Si NMR) and in the solid state (
29Si VACP/MAS NMR, crystal structureanalyses).