Control of metal-metal distance of dinuclear complex by counter anion; Structure and property of lanthanide tris(2-pyridine)carbinol complexes

Watanabe, Masayuki; Nankawa, Takuya; Wada, Atsushi*; Namiki, Kosuke*; Murata, Masaki*; Nishihara, Hiroshi*; Kimura, Takaumi

no journal, , 

A tripodal ligand, tris(2-pyridyl)carbinol affords a novel tetradentate coordination mode in homodinuclear lanthanide complexes, which exhibit remarkably short distances between metal ions. Structures of dinuclear complexes synthesized from triflates exhibited the same structure other than the difference in the bond lengths which was induced by lanthanide contraction across the lanthanide series from Pr to Lu. In these complexes, the distance between two lanthanide ions was remarkably short. In this study the same type of dinuclear complexes were synthesized from nitrates. The nitrate ion can coordinate in both monodentate fand bidentate fashions. Since ionic radii are dependent upon the coordination number, nitrate could affect the metal-metal distance. In fact, dinuclear complexes exhibited longer distance between lanthanide ions than the triflates due to the increase of ionic radii of lanthanide ions. Some features of these dinuclear systems, which are induced from the difference of metal-metal distance, will be discussed in the presentation.