PUB - Publikationen an der Universität Bielefeld

Alkali metal salts of a novel Janus scorpionate ligand [(Tr-Me)](-) with hard and soft donor sites (N, S) were synthesized by the reaction of 3-mercapto-4-methyl-1,2,4-triazole (L) with NaBH4 and KBH4, respectively, via Trofimenko's protocol. The resulting compounds were the sodium and potassium complexes [Na(Tr-Me)] (1), [K(Tr-Me)] (2) and the mixed ion compound [KNa(Tr-Me)] (3). [K(Tr-Me)] (2) was reacted with bismuth(III) chloride to afford the complexes [Bi(Tr-Me)(Cl)(mu-Cl)(2)](2) (5) and [Bi(Tr-Me)(Cl)(2)(mu-Cl)](n) (6). Compound 5 was formed when 2 was applied to BiCl3 in a molar ratio 2:1, while 6 was achieved when a ratio of 1:1 was used. The reaction of 3-mercapto-4-methyl-1,2,4-triazole (L) with BiCl3 led to the formation of the complex [Bi(L) 4(Cl) 2] Cl (7). The products were characterized by NMR and IR spectroscopy, elemental analyses and mass spectrometry. Solid state structures were determined by X-ray diffraction of single crystals of 1, 3, 3a, 5, 6 and 7. The alkali metal scorpionates 1-3 are coordination polymers with alternating orientation of the ligands. They dissociate in solution as observed in NMR measurements. Negative mode ESI-MS data also indicate the presence of monomers. The bismuth complex 5 is dimeric and 6 is polymeric, and both are bridged via chloro ligands. The three bismuth complexes 5, 6 and 7 have highly distorted octahedral coordination geometries. The influence of the stereochemically active lone pair was found to be most pronounced in the dimeric complex 5. The ligand Tr-Me and all bismuth complexes were also screened for their photo-luminescence activity. Whereas solutions of Tr-Me exhibit no luminescence, 7 is only emissive at 77 K, and 5 is emissive both at r.t. and 77 K.