Precursors of Titanium Carbonitride

Abstract

ABSTRACTA series of novel compounds was isolated in the course of exploratory work on the chemistry of titanium halides in liquid ammonia. This work was undertaken to study synthetic approaches to titanium-containing precursors of ceramic materials. Representative of these compounds is a mixed valence Ti(III)-Ti(IV) tetramer, [NH4+·NH3]2[Ti4Br4 (NH2)12]−2, which was produced by the reaction of potassium borohydride and titanium IV bromide in liquid ammonia at room temperature. Similar ammonium salts of either Ti(IV) or Ti(III) were also prepared. The reaction of the ammonium salts with sodium acetylide in liquid ammonia evolves acetylene in an amount equivalent to the ammonium ion present. This provided the charge of the complex and yielded novel titanium acetylide derivatives. The acetylides convert into titanium carbonitrides upon thermal treatment to 800°C.The reaction of titanium halides of their ammonolytic products with sodium acetylide in liquid ammonia to yield halogen-free acetylide precur-sors having a relatively high titanium content appears to be a convenient synthetic approach. This is made possible by the fact that the alkali metal halide by-products are soluble and easily separated in that reaction medium. This approach appears to be a generalized route applicable to a number of transition metal elements of interest.