New hybrids combined metalloviologens with Ag/Cu iodides exhibit reversible thermochromisms, photocurrent responses, whose mechanisms are disclosed.

Six new squarate-based complexes with 3-D networks, 2-D layers and 0-D clusters have been prepared. 5 and 6 feature the first examples of incorporating squarate with viologens in one lattice, which exhibit not only photocurrent responses but also reversible thermochromisms.

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A combination of N-arylstilbazolium organic nonlinear optical chromophores with iodoargentates results in five new hybrids, i.e., [(DAST)­(Ag2I3)] n (1), [(DMAQS)­(Ag2I3)] n (2), [(DPAS)­(Ag2I3)] n (3), [(DPTAS)2­(Ag5I7)] n (4), and [(CEMAS)2­(Ag5I7)] n (5). Among them, the former four are centrosymmetric, and 5 is non-centrosymmetrical (space group Pna21) with the introduction of a cyano group in an organic chromophore. The (Ag5I7) n 2n– chains in 4 and 5 are special, in which that of 4 is constructed from Ag5I10 building blocks with a μ6-I σ-bonding to six Ag ions, and that in 5 is the connection of a cubane-like Ag4I4 core with bridged AgI4 tetrahedra. UV/vis/near-IR adsorptions and near-IR photoluminescences have been observed. All the organic chromophores are stacked as head-to-tail arrangements, resulting in second harmonic generation (SHG) inactive in 1–4. But 5 is SHG active without J-aggregation of organic chromophore, whose symmetry break was driven by the formation of hydrogen bonds around the cyano group. The SHG activity of 5 originates from the polarizations of the asymmetric contribution of Ag5I9 4– unit mixing with non-centrosymmetrical (CEMAS)2 2+ pair. Theoretical calculations were carried out to disclose their electronic structures.

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