Stable 2.5-di-tert-butylphenylsilanetriol was prepared by a stepwise synthesis. This compound reacted with triethylenediamine and lanthanum silylamide to form a t :1 molecular complex and highly thermally stable lanthanosilsesquioxane, respectively.Key words: silanetriols, metallosiloxanes.In recent years, attention of researchers to stable silanetriols markedly increased because they can be used to prepare cage metallosiloxanes, which are highly interesting due to their catalytic properties, thermal stability, and also unusual magnetic properties. IOne of the most important features of the chemistry ofsilanols is high acidity of the SiOH group. Therefore, silanols are prone to form strong hydrogen bonds with both one another and other organic compounds, which results in various associates and complexes ranging from simple dimers to complex three-dimensional networks, z Finally, silanetriols are the closest analogs of silicic acid, which was found recently to take an active part (though indirectly) in the formation of bone tissue, because it binds aluminum, ruinous for this tissue (due to competition with calcium), into strong complexes. 3Up to now, several types of stable silanctriots are known, s namely, substituted aniline derivatives, Ar(Me3Si)NSi(OH)~, and alkylsi[anetriols, RSi(OH) 3, where R is a branched organic radical or an organometallic fragment. Among aromatic derivatives in which the Si(OH) 3 group is bound directly to the aromatic ring, the simplest phenylsilanetriol has been reported4; however, this compound is unstable and rapidly condenses.The subjects of our study were 2,5-di-tert-butylphenylsilanetriol (1) and 2,5-di-tert-butyl-l,4-bisftrihydroxysilyl)benzene (2). On the one hand, the silanetriol group in compound I is stericatly sufficiently hindered to make this compound highly stable and, on the other hand, it should be highly reactive, because the second ortho-position of the benzene ring is nonsubsti- yield (an equilibrium mixture of the initial compound and the final product) has been reported. 5 However. when we attempted to reproduce this procedure, we observed even at -78 ~ a different process, namely, cleavage of diethyl ether by the organolithium compound that formed, which gave EtOLi and [,4-di-tert-
Results and DiscussionSilanetriol ! was synthesized from 1,4-di-tert-butylbenzene by a four-step procedure shown in Scheme I." Synthesis of bromo-2.5-di-tert-butylbenzene contaminated by 12% 3,4-dibromo-terr-butylbenzene, inseparable by distillation. has been reported s
