Different Contributions of Aliphatic and Conjugated Organic Cations to Both the Crystal and Electronic Structures: Three Hybrid Iodoargentates Showing Two Isomers of the (AgI 2 ) – Chain

Three new hybrid iodoargentates (H 2 pipe) 0.5 (α‐AgI 2 ) ( 1 ), (Me 2 teda) 0.5 (α‐AgI 2 ) ( 2 ), and (H 2 dpe) 0.5 (β‐AgI 2 ) ( 3 ) have been synthesized under solvothermal conditions, whereby the aliphatic organic cations (H 2 pipe) 2+ and (Me 2 teda) 2+ (pipe = piperazine, teda = triethylenediamine) and the conjugated organic cation (H 2 dpe) 2+ [dpe = 1,2‐di(4‐pyridyl)ethylene] exhibit different contributions to both the crystal and electronic structures. The (H 2 pipe) 2+ and (Me 2 teda) 2+ cations direct the formation of α‐type (AgI 2 ) – polyanionic chains and influence the bandgaps of 1 and 2 indirectly by modulating the iodoargentate anionic structures. By contrast, the (H 2 dpe) 2+ cation directs the formation of a novel β‐type (AgI 2 ) – chain and changes the bandgap of 3 directly to make up the bottom of the conduction band. From 1 and 2 to 3 , a direct to indirect bandgap transformation and reduced bandgap can be observed (3.74, 2.88, and 1.99 eV for 1 – 3 , respectively). Relative to the bandgap of bulk AgI 2 , the bandgaps of 1 and 2 show a blueshift as a result of the quantum confinement effect, whereas the bandgap of 3 shows a redshift owing to the direct participation of the conjugated cation (H 2 dpe) 2+ in adjusting the bandgap.