Hampered Subcomponent Self-Assembly Leads to an Aminal Ligand: Reactivity with Silver(I) and Copper(II)

Insight into the ineffectiveness of a subcomponent self-assembly procedure between 4-aminopyridine (4-apy) and pyridine-2-carbaldehyde (2-pyA) led to a new aminal ligand (L). The combination of L with AgI gave a 2D luminescent network, in which the silver ions have a distorted triangular-pyramidal coordination geometry. The aminal is stable in acetonitrile and DMSO but decomposes in alcohol solvents. Moreover, we found that CuII also induced the decomposition of L, which led to Cu(pic)2, {[Cu(4-apy)4](ClO4)2}, and an unprecedented {[Cu4(pic)4(OH)2(H2O)6](ClO4)2} tetramer based on CuII ions and picolinic acid (Hpic) generated in situ. The decomposition pathway of L was clarified by a combination of single-crystal XRD analysis, NMR spectroscopy, and ESI-MS.