Lithium dicyanamide, its reactions with cyanuric chloride, and the crystal structures of LiN(CN)(2)(MeCN)(2) and LiCN(C5H5N)(2)

Reactions of dicyanamides with cyanuric chloride were investigated as possible routes to carbon nitrides. Anhydrous lithium dicyanamide (1) was synthesized from NaN(CN)(2) and LiCl in THF. Compound 1 was found to react with cyanuric chloride to form a yellow product, which forms an amorphous lithium-carbon nitride with an approximate formula CN0.7Li0.2 upon thermolysis to 700 degrees C. Upon heating to 1000 degrees C, the product decomposes with the distillation of lithium cyanide. Reactions between cyanuric chloride and trimethylstannyl dicyanamide were also investigated. Lithium dicyanamide was also found to trimerize and polymerize at 280-320 degrees C. Additionally, two Li-C-N complexes were structurally characterized. The bis (acetonitrile) adduct of 1 crystallizes with the lithium atoms linking the cyano nitrogens into infinite Li-N=C-N-C=N-chains, and the bis(pyridine) adduct of LiCN consists of infinite zig-zag -Li-C=N-chains. (C) 1997 Elsevier Science Ltd.