Ring-opening polymerization of coordination complexes: silver(i) complexes with bis(amidopyridine) ligands derived from thiophene

Abstract

The thiophene-based bis(N-methylamido-pyridine) ligand SC₄H₂-2,5-{C(O)N(Me)-4-C₅H₄N}₂ reacts with silver(I) salts AgX to give 1 : 1 complexes, which are characterized in the solid state as the macrocyclic complexes [Ag₂{SC₄H₂-2,5-(CONMe-4-C₅H₄N)₂}₂][X]₂, which have the cis conformation of the C(O)N(Me) group, when X = CF₃CO₂, NO₃, or CF₃SO₃ but as the polymeric complex [Ag_n{SC₄H₂-2,5-(CONMe-4-C₅H₄N)₂}_n][X]_n, with the unusual trans conformation of the C(O)N(Me) group, when X = PF₆. The bis(amido-pyridine) ligand SC₄H₂-2,5-{C(O)NHCH₂-3-C₅H₄N}₂ reacts with silver(I) trifluoroacetate to give the polymeric complex [Ag_n{SC₄H₂-2,5-(CONHCH₂-3-C₅H₄N)₂}_n][X]_n, X = CF₃CO₂. The macrocyclic complexes contain transannular argentophilic secondary bonds. The polymers self assemble into sheet structures through interchain CO⋯Ag and S⋯Ag bonds in [Ag_n{SC₄H₂-2,5-(CONMe-4-C₅H₄N)₂}_n][PF₆]_n and through Ag⋯Ag, CO⋯Ag and Ag⋯O(trifluoroacetate)⋯HN secondary bonds in [Ag_n{SC₄H₂-2,5-(CONHCH₂-3-C₅H₄N)₂}_n][CF₃CO₂]_n.