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The key Cl − ligand for metal‐to‐ligand charge transfer in mononuclear terpyridine ruthenium(II) and binuclear ruthenium(II) tetrapyridylpyrazine complexes
Author(s) -
Yoshikawa N.,
Yamabe S.,
Kanehisa N.,
Inoue T.,
Takashima H.,
Tsukahara K.
Publication year - 2011
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.1863
Subject(s) - ruthenium , chemistry , terpyridine , hexafluorophosphate , pyrazine , ligand (biochemistry) , crystallography , metal , bipyridine , photochemistry , stereochemistry , crystal structure , organic chemistry , catalysis , biochemistry , ionic liquid , receptor
Electronic structures of binuclear ruthenium complexes [Ru 2 (terpy) 2 (tppz)] 4+ ( 1A ) and [Ru 2 Cl 2 (L) 2 (tppz)] 2+ {L = bpy ( 2A ), phen ( 3A ), and dpphen ( 4A )} were studied by density functional theory calculations. Abbreviations of the ligands (Ls) are bpy = 2,2′‐bipyridine, phen = 1,10‐phenanthroline, dpphen = 4,7‐diphenyl‐1,10‐phenanthroline, terpy = 2,2′:6′,2″‐terpyridine, and tppz = tetrakis(2‐pyridyl)pyrazine. Their mononuclear reference complexes [Ru(terpy) 2 ] 2+ ( 1B ) and [RuClL(terpy)] + {L = bpy ( 2B ), phen ( 3B ), and dpphen ( 4B )} were also examined. Geometries of these mononuclear and binuclear Ru(II) complexes were fully optimized. Their geometric parameters are in good agreement with the experimental data. The binuclear complexes were characterized by electrospray ionization mass spectrometry, UV–Vis spectroscopy, and cyclic voltammograms. Hexafluorophosphate salts of binuclear ruthenium complexes of 3A and 4A were newly prepared. The crystal structure of binuclear complex 1A (PF 6 ) 4 was also determined. Orbital interactions were analyzed to characterize the metal‐to‐ligand charge‐transfer (MLCT) states in these complexes. The Cl − ligand works to raise the orbital energy of the metal lone pair, which leads to the low MLCT state. Copyright © 2011 John Wiley & Sons, Ltd.