Abstract
Treatment of 5‐methoxy‐5,6‐diphenyl‐4,5‐dihydro‐2__H__‐[1,2,4]triazine‐3‐thione (LH~2~OCH~3~) with compounds SnR~2~X~2~ (R = Me and Ph; X = Cl and NO~3~) afforded, for the first time, metal derivatives of a cyclic thiosemicarbazone. Treatment of LH~2~OCH~3~ with the appropriate diorganotin(IV) chloride in dichloromethane provided 1:1 complexes, but 1:2 derivatives were isolated when the nitrate salts in distilled water were used. The complexes were studied by mass spectrometry, IR and multinuclear (^1^H, ^13^C and ^119^Sn) NMR in solution, and also by ^119^Sn CP/MAS NMR spectroscopy and by X‐ray diffraction in the solid state. In all the complexes, the thiosemicarbazone had been modified by formation of a new C=N bond. In addition, the ligand LH had lost a hydrogen atom, acting as an anion. The crystal structures of [SnPh~2~(C~15~H~10~N~3~S)Cl] (1) and [SnMe~2~(C~15~H~10~N~3~S)~2~] (4) each consist of discrete molecules with the tin atom bonded to the sulfur and amine nitrogen atoms to give a four‐membered chelate ring with the [1,2,4]triazine modified. For phenyl derivative 1, the tin atom is in a trigonal‐bipyramidal environment with the phenyl rings in equatorial positions, and for complex 4 it is in an octahedral arrangement, with the methyl groups in axial positions. The ^119^Sn CP/MAS NMR spectra of the complexes are in accordance with these structures. The values obtained indicate a five‐coordinate geometry for [SnMe~2~(C~15~H~10~N~3~S)Cl] (2) and suggest a coordination number of six for complex 3. The ^119^Sn spectra of complexes in solution depend on the coordinating capacity of the solvents. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)