From pyridoxalrhodanine to a novel 7-azacoumarin complex of dimethylthallium(III) in a one-pot synthesis

The hydrolysis of pyridoxalrhodanine in a basic medium containing the dimethylthallium(III) cation afforded the compound [TlMe2(L)]·H2O (1·H2O) [HL=5-(hydroxymethyl)-8-methyl-3-thiol-7-azacoumarin]. This compound was characterized in solid state by IR spectroscopy and in solution by 1H and 13C{1H} NMR spectrometry. X-ray diffraction showed that the crystal consists of associated TlMe2(L) units and hydrogen bonded water molecules. The L− anion is bound to the metal mainly by a bridging S atom [Tl–S=2.9458(18) Å; 2.9616(16) Å], although secondary interactions through O atoms (Tl–O: 2.861(5); 2.900(5) Å)] are also present. The longer Tl–O interaction and the hydrogen bonds of the water molecules give rise to a tridimensional polymeric structure.