Iodoargentate/iodobismuthate-based materials hybridized with lanthanide-containing metalloviologens: thermochromic behaviors and photocurrent responses

Abstract

Two new types of iodoargentate/iodobismuthate-based inorganic–organic hybrids were prepared and structurally characterized as {[Ln₂(dpdo)(DMF)₁₄](Ag₁₂I₁₈)}_n (bpdo = 4,4′-bipyridine N,N′-dioxide, Ln = La (1), Nd (2), Sm (3)) and {[Ln(dpdo)(DMF)₆](Bi₂I₉)₂}_n (Ln = La (4), Pr (5), Er (6)). These lanthanide–silver/bismuth heterometallic hybrids feature the novel templates of lanthanide-containing metalloviologen analogs, i.e., [Ln₂(dpdo)(DMF)₁₄]⁶⁺ (dimers for 1–3) and [Ln(dpdo)(DMF)₆]_n³ⁿ⁻ (1-D chains for 4–6). The (Ag₁₂I₁₈)_n⁶ⁿ⁻ chains in 1–3 are constructed from edge-sharing Ag₆I₁₂ units, and (Bi₂I₉)³⁻ clusters in 4–6 are defined by two face-sharing BiI₆ otcahedra. The versatile weak interactions between metalloviologens and metal iodides stabilize the structures. Upon the introduction of metalloviologens, reversible thermochromism can be found in 1–6. Besides, electrodes with films of 1–6 exhibit effective and repeatable photocurrent responses. Finally, the possible thermochromism and photocurrent response mechanisms are also discussed.