Semicarbazides and their derivatives are promising ligands for chelate complexation and are often parts of multicomponent organic molecules prepared by template condensations. It was shown [1] that the most important factors for condensation on a metal matrix include the nature of the metal and the reaction medium. This gives systems of various sizes up to macrocycles containing 23 atoms or more [2]. As a result of a template reaction, the metal atom functioning as a matrix is incorporated in the final product. In some known examples, however, the central metal monitors the condensation route or transformations of the starting ligands without inclusion of the template center in the final product. Such processes are known as transit template reactions [1]. For example, the reaction of thiosemicarbazide with benzene in the presence of NaBH 4 gives a cyclic triazine or its dimer [3]. Analogously, the reaction of hydrazine with α -lactams yielded 1,2,4-triazine-3,5-diones [4,5]. This reaction is not exceptional; other examples of cyclization of acyclic molecules have been reported [6][7][8][9].Our attempt to prepare the reaction product of semicarbazidodiacetic acid H 2 NC ( O ) NHN ( CH 2 COOH ) 2 with zinc chloride resulted in isolation of a new cyclic triazine that can be used as a ligand for complexation with transition metals. EXPERIMENTAL Synthesis of çé 2 ëëç 2 ç 2 · 1/2 H 2 O ( I ) . Semicarbazidodiacetic acid (0.38 g, 0.002 mol) in 15 ml of methanol was added to a warm solution of ZnCl 2 (0.23 g, 0.001 mol) in 20 ml of methanol. The white square-plate crystals of I precipitated on slow cooling of the solution (yield ~40% ). The compound is soluble in water, methanol, and ethanol; mp = NNHCONHCOC 140-142° C (mp of semicarbazidodiacetic acid is 161° C).
Synthesis of [é 2 ëëç 2ç 2 ] 2 Cu ( II ) . Compound I (0.36 g, 0.002 mol) in 20 ml of methanol was added to a warm solution of CuCl 2 · 2 H 2 O (0.17 g, 0.001 mol) in 20 ml of a water-methanol mixture. The solution color slowly changed from green to violet, and light violet crystals precipitated (yield ~45% ). The compound is soluble in water, methanol, and ethanol. X-ray diffraction analysis. The unit cell parameters and the experimental data for crystals of I and II were measured on a KUMA KM-4CCD diffractometer (graphite monochomator, MoK α radiation) at T = 150 K for I and 100 K for II . The distance between the crystal and the CCD detector was 60 mm. For compound I , 6864 reflections were collected in four series ( ϕ = 0°, 90°, 180°, 270° ), altogether 465 frames, with a rotation step of 0.75° for the ω angle. The recording time for one frame was 5 s. For compound II , the intensity set contained 1664 reflections, 291 frames, with a recording time of 45 s for each frame. The small amount of experimental data is due to the crystal size (one of the crystal dimensions did not exceed 0.01 mm) and the For C 5 H Abstract -A new organic compound, 2'-(3,5-dioxo-1,2,4-triazinane-1-yl)acetic acid, was prepared by transit template synthesis, and its crystal structure...