New cyclodisilazane derivatives

Abstract

Cyclodisilazanes with mixed silicon-substituted groups {Cl(CH8)RSi[SiR(CH8)N]2SiR(CH3)Cl} can be prepared either by heating mixtures of [R(CH3)SiNH]3 and R(CH3)SiCl2 or by treating HN[Si(CH3)RCl]2 with butyllithium and heating the product. One or both of the methods are shown to be applicable where R is ethyl, vinyl, phenyl, or 3,3,3-trifluoropropyl as well as methyl. The properties of the intermediate cyclotrisilazanes and disilazanes as well as the dialkylamino derivatives of the cyclodisilazanes are described.

Synthesis and structure of 1,3-bis(hydroxysilyl)-2,4-dimethyl-2,4-diphenylcyclodisilazane

“…The 1,3-bis(chloro-silyl)-2,4-dimethyl-2,4-diphenylcyclodisilazane 3 and 4 were synthesized by stepwise reactions as shown in Scheme 3. We found that nearly quantitative conversion to such cyclodisilazanes could occur at 70 C which offered a mild condition compared to the previously reported work [19,20]. When the ring-closure reaction of 1 or 2 was performed using an equivalent of n-BuLi in toluene, 3 was obtained in large quantities as a mixture of cis/trans isomers while 4 was formed as trans-cyclodisilazane.…”

“…For these mixed phenyl-substituted cyclodisilazanes, isomeric structures probably appeared as a result of the transmission of substituent effects throughout the Si 4 N 2 skeleton which indicated that long-range coupling could occur through silicon in the structure C 6 H 5 SiCH 3 [19]. Of particular interest was the spectrum of 3, the mixture of cis/trans isomers was clearly observed in the 29 Si and 13 C NMR spectra.…”

“…The mechanism features primary metalation at nitrogen of a 1,3-dichlorodisilazane followed by a bimolecular condensation to a trisilylamine structure with subsequent ring closure [19]. The 1,3-bis(chloro-silyl)-2,4-dimethyl-2,4-diphenylcyclodisilazane 3 and 4 were synthesized by stepwise reactions as shown in Scheme 3.…”

“…We have recently demonstrated that these cyclodisilazanes possess favorable thermal stability with good prospects. Breed and Bao [19,20] respectively reported the preparation of (ClSiMePh) 2 (NSiMePh) 2 , which was simply characterized by 1 H NMR and IR absorption as indication of the presence of Si 4 N 2 skeleton. However, no further evidence was described and its molecular structure remained so far unknown.…”

Synthesis and characterization of alternate copolymers constructed by 1,3‐bis(diphenylsilyl)‐2,2,4,4‐tetraphenylcyclodisilazane units with oligo‐dimethylsiloxane segments

“…11 In this reaction, the yield of BcPTPC was highly influenced by the polarity of the solvents used. In nonpolar solvents such as the xylene-hexane mixture solvent, the ringclosure reaction of DCTPS can smoothly take place, and the yield of BcPTPC is high, nearly 73.2%.…”