Structure of Methanol Solvated Iodozinc(II) Complexes in Solution

Abstract

The structures of the solvated zinc ion and the solvated zinc–iodide complexes in methanol solution have been determined by EXAFS. The zinc ion is six-coordinated in an octahedral fashion with a mean Zn–O bond distance of 2.071(4) Å. According to the stability constants of the zinc–iodide system in methanol solution the first complex, ZnI+, is suppressed, which may indicate that a coordination change takes place at this step. On the other hand, the second complex, ZnI2, predominates at excess of iodide. The methanol solvated ZnI2 complex has a tetrahedral structure with mean Zn–I and Zn–O bond distances of 2.55(1) and 1.99(1) Å, respectively. The mean Zn–I bond distance in a solution containing a maximal content of ZnI+, ca. 12%, strongly indicates that the first complex also has a tetrahedral structure.