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Rutheniumethynyl‐Triarylamine Organic−Inorganic Mixed‐Valence Systems: Regulating Ru‐N Electronic Coupling by Different Aryl Bridge Cores
Author(s) -
Ou YaPing,
Zhang Jing,
Wang Aihui,
Yuan Ande,
Yin Chuang,
Liu Sheng Hua
Publication year - 2020
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.202000879
Subject(s) - valence (chemistry) , chemistry , time dependent density functional theory , ruthenium , density functional theory , aryl , cyclic voltammetry , molecule , electron transfer , charge density , crystallography , electrochemistry , photochemistry , computational chemistry , electrode , organic chemistry , catalysis , physics , quantum mechanics , alkyl
Four rutheniumethynyl‐triarylamine complexes 1 – 4 with different aryl bridge cores were prepared. The solid structures of complexes 2 – 4 were fully confirmed by X‐ray single‐crystal diffraction analysis. Two consecutive one‐electron oxidation processes of complexes 1 – 4 were attributed to the ruthenium and nitrogen centers, as revealed by cyclic voltammetry and square‐wave voltammogram. Results also showed decreasing potential difference Δ E of complexes 1 , 3 , and 4 , with the largest value for 2 . Upon chemical oxidation of complexes 1 – 4 by 1.0 eq oxidation reagents FcPF 6 or AgSbF 6 , the mixed‐valence complexes, except for 2 + , show characteristic broad NIR absorptions in the UV‐vis‐NIR spectroscopic experiments. NIR multiple absorptions were assigned to NAr 2 →RuCp*(dppe) intervalence charge transfer (IVCT) and metal‐to‐ligand charge transfer transitions by TDDFT calculations. Coupling parameter ( H ab ) from Hush theory revealed that increasing electronic communication in 1 + , 3 + , and 4 + . Electron density distribution of the HOMO for neutral molecules ( 1 , 3 , and 4 ) and spin density distribution of the corresponding single‐oxidized states ( 1 + , 3 + , and 4 + ) increases progressively on the bridge as the size of the aromatic system increases, proving incremental contributions from bridge cores during oxidation.