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

The 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 β 2 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)](ClO 4 ) (1) comprises a one-dimensional coordination polymer [Ag 2 -(1-mtri) 2 ] n 2n+ , showing a 1:1 ratio of ligand to metal. By contrast, the mercury complex [Hg(1-mtri) 2 ](ClO 4 ) 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.