Quaternary Phosphorus‐Induced Iodocuprate(I)‐Based Hybrids: Water Stabilities, Tunable Luminescence and Photocurrent Responses

Abstract

Four (triphenyl)phosphonium‐based quaternary phosphorus salts with different substituents (varying from methyl to n‐butyl) were selected to be structural directed agents (SDAs) to construct four iodocuprate(I) hybrids via solution method, i.e., [(PPh3Me)(Cu3I4)]n (1), [(PPh3Et)(Cu3I4)]n (2), (PPh3iPr)2(Cu2I4) (3), [(PPh3nBu)(Cu3I4)]n (4). The inorganic iodocuprates in 1, 2 and 4 are 1‐D (Cu3I4)nn– chains constructed from Cu5I11 units, but (Cu2I4)2– in 3 is a di‐nuclear cluster. Interestingly, the strength of Cu···Cu and π–π stacking interactions are weakened with the lengthening of alkyl groups on P‐atom. The best water stability of 4 can be ascribed to the better hydrophobicity of n‐butyl group, which deters the dispersing of organic and inorganic moieties and as a result, inhibit hydrolysis reaction. Furthermore, all compounds exhibit typical reversible luminescent thermochromic behaviors, among which 4 exhibits blue emission and the quenching of higher energy (HE) zone in 1 and 2 are led by strong π–π stacking interactions. Besides, effective and repeatable photocurrent responses can be detected in these compounds. In all, by systematically introducing alkyl groups into (triphenyl)phosphonium as SDAs to prepare hybrid iodocuprates, we can find that the longer alkyl groups can achieve stronger tunable PL materials with enhanced water stabilities.