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Direct Observation of Confined I − ⋅⋅⋅I 2 ⋅⋅⋅I − Interactions in a Metal–Organic Framework: Iodine Capture and Sensing
Author(s) -
Hu YueQiao,
Li MuQing,
Wang Yanyan,
Zhang Tao,
Liao PeiQin,
Zheng Zhiping,
Chen XiaoMing,
Zheng YanZhen
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201702087
Subject(s) - iodide , polarizability , copper , iodine , electrical resistivity and conductivity , metal , conductivity , crystallography , chemistry , molecule , single crystal , redox , ion , crystal (programming language) , materials science , chemical physics , inorganic chemistry , physics , organic chemistry , quantum mechanics , computer science , programming language
Abstract Herein a strategy is reported for capturing and sensing iodine by strong I − ⋅⋅⋅I 2 ⋅⋅⋅I − interaction, confined in a metal‐organic framework, [Tb(Cu 4 I 4 )(ina) 3 (DMF)] ( 1 ) (ina=isonicotinate). As revealed by single‐crystal X‐ray crystallography, the uptaken I 2 molecules directly contact the {Cu 4 I 4 } n chains, virtually forming an electronically polarizable tetraiodide anion (I 4 2− ) through strong I − ⋅⋅⋅I 2 ⋅⋅⋅I − interaction. As such, a quasi‐copper‐iodide layer of {Cu 4 I 5 } n with semiconducting characteristics results, leading to a significant enhancement ( Δ σ =10 7 times) in electrical conductivity over the I 2 ‐free 1 . The effect observed is several orders of magnitude higher than those reported due to iodine⋅⋅⋅aromatic interactions ( Δ σ =10 2 times) and by interactions between I 2 and a redox‐active metal centre ( Δ σ =10 4 times). The drastic enhancement in electrical conductivity was used to switch on/off an LED bulb, suggesting the possibility of electrically sensing I 2 .