Silver(I) and Mercury(II) Complexes with 1‐Methyl‐1,2,4‐triazole as Models for Metal‐Mediated Base Pairs – Formation of Discrete Complexes in Solution vs. One‐ and Two‐Dimensional Coordination Polymers in the Solid State

Abstract

AbstractThe coordination chemistry of 1‐methyl‐1H‐1,2,4‐triazole(1‐mtri) with respect to the linearly coordinating metal ions silver(I) and mercury(II) has been established. The ligand serves as a model nucleobase for the artificial 1,2,4‐triazole nucleoside. Solution studies show that 2:1 complexes are formed with both metal ions in water. Mercury(II) forms more stable complexes than silver(I), with a stability constant of log β2 of 10.5 ± 2.5 vs. 4.3 ± 0.4 for the silver(I) complex. In the solid state, different types of cationic coordination polymers are formed. The silver complex [Ag(1‐mtri)](ClO4) (1) comprises a one‐dimensional coordination polymer [Ag2(1‐mtri)2]n2n+, showing a 1:1 ratio of ligand to metal. By contrast, the mercury complex [Hg(1‐mtri)2](ClO4)2 (2) retains a 2:1 stoichiometry while forming a two‐dimensional coordination polymer. In compound 2, mercury(II) is coordinated in a distorted octahedral fashion, with two normal and four long bonds, resulting in a compressed octahedron.