New U- and Y-shaped components for metallosupramolecular assemblies: synthesis and coordination chemistry of 2,6-bis(3-pyridyloxy)pyrazine

Abstract

The new ligand 2,6-bis(3-pyridyloxy)pyrazine (1) has been prepared and characterized. The ligand has inherent flexibility due to the two ether linkages and its ability to act as either a U-shaped, Y-shaped or W-shaped component in the preparation of metallosupramolecular assemblies has been assessed by reactions of 1 with late transition metal ions. Reaction with Cu(NO₃)₂ gives a discrete dimetallacyclic complex, with the ligand acting as a U-shaped component by binding through only the pyridine donors, and contains a rare Cu₂(μ-ONO₂)₂ unit. Reaction with CuI also gives a discrete dimetallacyclic complex, with the ligand again acting as a U-shaped component, and the complex containing a central Cu₂(μ-I)₂ unit. Reaction with [Cu(CH₃CN)₄]BF₄ gives the first example of a chiral 2-dimensional [6∶3] metallopolymeric net species, with the ligand acting as a Y-shaped component by binding through both the pyridine and pyrazine donors. Reaction with AgNO₃ gives a centrosymmetric 2-dimensional [6∶3] metallopolymeric net species, with the ligand again acting as a Y-shaped component.