Four-Coordinate As^III-N,S Complexes: Synthesis, Structure, Properties, and Biological Relevance

Air-stable four-coordinate AsIII complexes, [As(L4)Cl] (1) and [As(L4)I] (2), were prepared using a rearranged form of the deprotonated benzothiazoline ligand, 2-(pyridin-2-yl)-2,3-dihydrobenzo[d]thiazole. Complexes 1 and 2 have been characterized by FTIR, 1H NMR, UV−vis, and elemental microanalysis. The solid-state structure of 2 was also solved. The unusual and rare four-coordinate geometry of 2 elucidates possible binding modes and properties of N,S-ligated AsIII that may be encountered in biology.