Crystal Structure of Zinc(II) Complexes with 2-Ethyl-3-hydroxy-4 H -pyran-4-thione and 2-Ethyl-3-hydroxy-4 H -pyran-4-selenone

Zn(II) complexes with 2-ethyl-3-hydroxy-4H-pyran-4-thione, [Zn(ehpt)2], and 2-ethyl-3-hydroxy-4H-pyran-4-selenone, [Zn(ehps)2], were synthesized and characterized by single crystal X-ray diffraction. Complexes are isostructural, crystallize in sp. gr. P21/n with Z = 4. The Zn2+ ion has a distorted tetrahedral coordination with two S or Se atoms and two O atoms from ehpt or ehps, respectively. In vitro, insulin-mimetic activities of [Zn(ehpt)2] and [Zn(ehps)2] are much higher than that of Zn complex with maltol, 3-hydroxy-2-methyl-4H-pyran-4-one, [Zn(hmpo)2]}, where Zn coordination is completed by H2O molecules. It suggests that Zn complexes with distorted tetrahedral coordination might exhibit higher insulin-mimetic activities than those with octahedral or square pyramidal coordination.