Synthesis of an N‐Functionalized 1,3‐Diaza‐ and a P‐Functionalized 1,3‐Diphospha‐2,4‐disilacyclobutane

Abstract

Reactions of dichlorodiorganosilanes with ammonia proceed with complete cleavage of hydrogen chloride to afford six-and eight-membered cyclosilazanes and higher condensation products"]. Sterically demanding substituents lead to short-chain acyclic silazanes[21. In this connection neither the formation of a four-membered ring [R2Si-NHI2 nor of an intermediate product R2SiCI-NH2 has been observed.Cyclosilaphosphanes were obtained by reaction of dichlorodiorganosilanes with lithium phosphide or metalated organoph~sphanes~'~. The annelation can be attributed to the marked tendency of the initially formed unstable diphosphinosilanes to rearrange, although bis(tert-butylphosphino)dimethylsilane, Me2Si(PHtBu),, has been isolated and after lithiation used in the synthesis of cyclosilaphosphanes"].By allowing difluorodiorganosilanes to react with lithium amide or lithium phosphide, we obtained the surprisingly stable N-(fluorosily1)amines 1 and 2, and the N-(fluorosi1yl)phosphane 3 (b.p.=55 "C/18 torr, 38 "C/19 torr, and 70 "C/4 torr).In an analogous fashion to the isoelectronic compound (~Bu),S~F(OH)['~, 1 and 3 show no tendency to condense.

Flash Vacuum Thermolysis: First Gas-Phase Generation of Unhindered Silylidenephosphanes and Characterization by Photoelectron Spectroscopy

“…The presently known 2,2,4,4-tetramethylcyclodisilaphosphanes (2,2,4,4-tetramethyl-1,3-diphospha-2,4-disilacyclobutanes) are limited to 1,3-di- tert -butyl, , 1,3-diphenyl, , and 1,3-bis(chlorodimethylsilyl) derivatives. A few cyclodisilaphosphanes substituted on silicon by groups other than methyl have been also described, − as well as 1,3,5-triphenyl-2,2,4,4,6,6-hexamethylcyclotrisilaphosphane, and triphosphatrisilacyclohexanes …”

Stable O,O‘-Bis(hydroxylamino)silanes R2Si(ONH2)2 and Isomeric N,N‘- and O,O‘-Bis(silylhydroxylamino)silanes R2Si(NHOSiR3)2 and R2Si(ONHSiR3)2

“…Anionic, radicalic, and neutral silyl group migrations and silyl group insertions into the N−O bond have been described. ,− However, bis(hydroxylamino)silanes have not been isolated so far. Knowing that in contrast to carbon chemistry it is possible to stabilize compounds with two or three electronegative groups such as OH, NH 2 , and PH 2 bonded to one silicon atom, we tried to prepare bis(hydroxylamino)silanes and report our recent results.…”