Synthesis and Photochemical Properties of Re(I) Tricarbonyl Complexes Bound to Thione and Thiazole-2-ylidene Ligands

Abstract

<p>Three Re(I) tricarbonyl complexes, with general formulation Re(N^L)(CO)<sub>3</sub>X (where N^L is a bidentate ligand containing a pyridine functionalized in the position 2 with a thione or a thiazol-2-ylidene group and X is either chloro or bromo) were synthesized and their reactivity explored in terms of solvent-dependent ligand substitution, both in the ground and excited states. When dissolved in acetonitrile, the complexes bound to the thione ligand underwent ligand exchange with the solvent resulting in the formation of Re(NCMe)<sub>2</sub>(CO)<sub>3</sub>X. The exchange was found to be reversible, and the starting complex was reformed upon removal of the solvent. On the other hand, the complexes appeared inert in dichloromethane or acetone. Conversely, the complex bound to the thiazole-2-ylidene ligand did not display any ligand exchange reaction in the dark, but underwent photoactivated ligand substitution when excited to its lowest metal-to-ligand charge transfer manifold. Photolysis of this complex in acetonitrile generated multiple products, including Re(I) tricarbonyl and dicarbonyl solvato-complexes as well as free thiazole-2-ylidene ligand.</p>

Synthesis, Crystal Structures, and Antimicrobial and Antitumor Studies of Two Zinc(II) Complexes with Pyridine Thiazole Derivatives

“…Therefore, the introduction of pyridine hydrazone group into molecule containing thiazole is likely to produce stronger biological activity according to the synergistic effect of drug combination principles. Because of the particularity of the structures, thiazole ligands containing pyridine and hydrazone groups with multiple coordination sites often have good metal coordination ability which can form stable complexes with different transition metal [ 8 , 9 ]. Besides, the spatial conformation of the complex is determined by its coordinated modes, which have great influence on the biological properties of the compound [ 10 – 12 ]; the studies on transitional metal compounds of pyridine thiazole ligands have been of great significance.…”