Template Synthesis of Iodocuprate and Iodoargentate with Photocatalytic Activity and Second Harmonic Generation Efficiency

In virtue of the cationic tri(pyridin-4-yl)amine (TPA) derivatives acting as the templates, two iodometallates, [Me₃HTPA]₂[CuI₃][Cu₁₀I₁₆] (1) and [Me₃TPA][Ag₅I₈] (2), were constructed with different architectures. Compound 1 features a discrete [Cu₁₀I₁₆]^6– cluster, which is further combined with [CuI₃]^2– and two [Me₃HTPA]⁴⁺ moieties through electrostatic interactions to result in a 3D supramolecular framework. Two types of infinite Ag–I chains with different orientations are formed in iodoargentate 2, and adjacent chains, together with in situ N-methylated cations, are further aggregated into a final 3D supramolecule. The syntheses, crystal structures, and optical properties have been studied. Notably, compound 1 displays efficient visible-light-driven photocatalytic performance for the degradation of dye pollutants. The catalytic mechanism was investigated through radical trapping experiments as well as theoretical calculations. Moreover, both the iodocuprate and iodoargentate hybrids exhibit second harmonic generation (SHG) effects, which are comparable to and even better than that of KH₂PO₄, indicating that the iodometallate hybrids templated by TPA-based cations could potentially serve as new candidates for second-order nonlinear optics (NLO) materials.