Several zinc(II) coordination compounds containing both picolinate and piperazine were prepared through various reactions. We found that the nature of the product can be controlled by the amount of added piperazine. At lower amounts of piperazine, the dinuclear compound [{Zn(pic)$_2$}$_2$(pz)]‧Et$_2$O was formed, whereas at higher amounts, the one-dimensional coordination polymer [Zn(pic)$_2$(pz)]$_n$ was obtained. In both coordination compounds, piperazine is bound in a bidentate bridging manner. We also studied the reactions of the synthesized compounds with picolinic acid in an alcohol medium (methanol or ethanol). In these reactions, piperazine got protonated, while the resulting picolinate coordinated to zinc(II) ion. Ionic compounds composed of pzH$_2^{2+}$ and [Zn(pic)$_3$]$^–$ ions were formed.
|
