Synthesis and structures of new metallocene derivatives of lanthanides. Molecular structures of the complexes (C13H9)2Eu(THF)2 and (C5Me4H)2YbI(THF)

Abstract

The divalent europium bis fluorenyl complex (C 13 H 9 ) 2 Eu(THF) 2 was synthesized by the metathesis reaction of EuI 2 (THF) 2 with two equivalents of fluorenylpotassium and by the protolytic substitution of the naphthalene ligand in the (C 10 H 8 )Eu(THF) 2 complex using the reaction with fluorene. According to X ray diffraction data, the complex displays a skewed sandwich structure, in which one fluorenyl ligand is η 5 coordinated to the metal atom, whereas the η 3 coordination mode makes a great contribution to the coordination of another ligand. The (C 5 Me 4 H) 2 YbI(THF) complex was synthesized by the reaction of YbI 3 (THF) 2 with two equivalents of (C 5 Me 4 H)K. The structure of the complex was established by X ray diffraction.Since lanthanides are electropositive and met al-ligand interactions in their organic derivatives are predominantly ionic, ligands capable of forming stable organic anions that compensate the positive charge of the cations are conventionally used in these compounds. 1 This is why complexes with monoanionic η 5 coordinated carbocyclic ligands (primarily, with cyclopentadienyl ligands) are the most well studied lanthanide deriva tives. 1,2 The stability and reactivity of organic derivatives of rare earth metals are determined mainly by the high metal-carbon bond ionicity and large ionic radii. These properties, combined with a high positive charge on the metal center, are responsible for very high sensitivity of these compounds to the degree of steric saturation of their coordination sphere. In this connection, ligands used in rare earth chemistry should be rather large and provide the saturation of the coordination sphere, result ing in kinetic stability of metal complexes. Polymethylat ed cyclopentadienyl ligands meet all these requirements, and the use of these ligands in organolanthanide chemis try resulted in extensive progress in this area and allowed the synthesis of a wide range of compounds with unique reactivity.

Steric control in the metal–ligand electron transfer of iminopyridine–ytterbocene complexes

“…32 On the other hand, they are in good accord with Yb-C bond distances measured in related eight-coordinated Yb III complexes of the state-of-the-art {i.e. (η 5 -C 5 Me 4 H) 2 YbI(THF) [Yb-C mean 2.60(4) Å], 33 . All these data taken together largely support the hypothesis of a trivalent oxidation state for the ytterbium ion in 3a as a result of one-electron metal oxidation along with a reduction of the coordinated IPy ligand to the state of a radical-anionic species.…”

DFT studies of electronic and nonlinear optical properties of a novel class of excess electron compounds based on multi-alkali metal atoms-doped Janus face C13H10F12

“…Herein, inspired by phenalene (C 13 H 9 ) [40][41][42][43][44] that is a substance produced by incomplete combustion of petroleum fuel, we designed an interesting three-ring Janus face system C 13 H 10 F 12 (see Fig. 1).…”