Solvent-cooperatively directed iodoargentate hybrids: Structures and optical properties

Abstract

Using protonated methylpiperazine as countercations, seven iodoargentates, [(N-mepipzH₂)₄(Ag₄I₁₂)] (1), [(N-mepipzH₂·H₂O)₂(Ag₂I₆)] (2), [(N-mepipzH₂·2DMSO)(Ag₄I₆)]_n (3), [(N-mepipzH)(AgI₂)]_n (4), [(2-mepipzH₂·H₂O)₂(Ag₂I₆)] (5), [(2-mepipzH₂·4DMSO)(Ag₁₀I₁₂)]_n (6) and [(2-mepipzH)(Ag₂I₃)]_n (7) (N-mepipz = N-methylpiperazine, 2-mepipz = 2-methylpiperazine, DMSO = dimethyl sulfoxide), have been synthesized in different solvents. 1 and 2 consist of [Ag₄I₁₂]⁸⁻/[Ag₂I₆]⁴⁻ anionic clusters and discrete [N-mepipzH₂]²⁺/hydrogen bonded aggregate [N-mepipzH₂·H₂O]²⁺, respectively. 3 and 4 are constructed from 4-connected Ag₄I₈ and AgI₄ tetrahedral building units with γ-Si (gsi) and cristobalite topologies, respectively, while the hydrogen bonded aggregate [N-mepipzH₂·2DMSO]²⁺ and chain-like [N-mepipzH]⁺_∞ are intercalated in the corresponding channels. 5 and 6 consist of [Ag₂I₆]⁴⁻ clusters/[Ag₁₀I₁₂]_n²⁻ chains and hydrogen bonded aggregates [2-mepipzH₂·H₂O]²⁺/[2-mepipzH₂·4DMSO]²⁺, respectively. 7 is constructed from 6-connected Ag₄I₁₀ units with hxl/Shubnikov topological network, while the hydrogen bonded [2-mepipzH]⁺_∞ chains are located between neighboring layers. Striking difference of inorganic frameworks exhibit the remarkable cooperative directing effect of solvents and organic cations on the structures and bonding features of iodoargentates, which can probably be used as an effective route to the construction of iodoargentates. The optical absorption spectra of 1–7 are investigated.