Abstract

Treatment of 5-methoxy-5,6-diphenyl-4,5-dihydro-2H-[1,2,4]triazine-3-thione (LH2OCH3) with compounds SnR2X2 (R = Me and Ph; X = Cl and NO3) afforded, for the first time, metal derivatives of a cyclic thiosemicarbazone. Treatment of LH2OCH3 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 (1H, 13C and 119Sn) NMR in solution, and also by 119Sn 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 [SnPh2(C15H10N3S)Cl] (1) and [SnMe2(C15H10N3S)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 119Sn CP/MAS NMR spectra of the complexes are in accordance with these structures. The values obtained indicate a five-coordinate geometry for [SnMe2(C15H10N3S)Cl] (2) and suggest a coordination number of six for complex 3. The 119Sn spectra of complexes in solution depend on the coordinating capacity of the solvents. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)