Azomethine derivatives. Part VIII. Preparation of some diphenylketiminosilanes, and the use of diphenylketiminotrimethylsilane to prepare diphenylketiminoboranes
Abstract
Improved procedures for the preparation of Ph2C:NSiR3(R = Me, Et, or Ph) from R3SiCl + Ph2C:NLi are described. Ph2C:NSiPh3 can also be prepared from Ph3SiCl + 2Ph2C:NH. SiCl4 and 4Ph2C:NLi give the new compound (Ph2C:N)4Si.
Reactions between Ph2C:NSiMe3(I) and boron halides, generally in toluene, provide convenient routes to diphenylketiminoboranes. The trihalides BF3(as BF3, OEt2),BCl3, and BBr3 with (I) give diphenylketiminoboron dihalides Ph2C:NBX2. With two molecules of (I) the same trihalides give Ph2C:NBX2+(Ph2C:N)3B, apparently through disproportionation of the monohalides (Ph2C:N)2BX, which could not be isolated. BCl3 with three molecules of (I) gives (Ph2C:N)2B. Similar reactions between (I) and PhBCl2, the catechol derivative C6H4O2BCl, Ph2BCl, and (mesityl)2BF have been used to prepare two new apparently dimeric ketiminoboranes, (Ph2C:NBPhCl)2 and (Ph2C:NBO2C6H4)2, and three new monomeric ketiminoboranes (Ph2C:N)2BPh, Ph2C:NBPh2, and Ph2C:NB(mesityl)2.
I.r. spectroscopic details of the ketimino-silanes and -boranes are given, and the mass spectrum of (Ph2C:N)4Si is briefly discussed.