Molecular Structure of Fluorenyllithium^,

Abstract

The orange precipitate obtained after the well-known preparation of fluorenyllithium was recrystallized from a solution of benzene or toluene in order to get orange-red crystals which were of sufficient quality for X-ray diffraction. By this procedure we succeeded in redetermining the molecular structure of a donor-free unsubstituted fluorenyllithium compound, which might be the smallest alkali-metal compound containing a donor-free cyclopentadienyl-like ligand within an annelated ring system to date. The description of the bonding situation is based on ab initio calculations as well as on a comparison with analogous compounds.

Influences of the substituents on the M–M bonding in Cp4Al4 and Cp2M2X2 (M = B, Al, Ga; Cp = C5H5, X = halogen)

“…It was discussed that metal-metal bonding occurs through four highly Further, compared to their mono-and trivalent analogs, little is known about divalent aluminum complexes [10,27] . In 1998, Schnöeckel et al [43] described compounds derived from Cp*Al and AlI 3 that possess Al ions that may be considered to interact as Al(II)-Al(II) bonds (i.e., the [Cp*AlI-AlI 3 ]anion). Similarly, the 5 synthesis of the compound Cp*Al-AlAr 3 was reported by Cowley in 2001.…”

Reaction of 9-trimethylsilylfluorenyllithium with nitriles: Organolithium compounds

“…3), in which a lithium atom was coordinated with two ligands acting as η 3 -azaallyl and η 6 -aryl fashions. There was a few of η 6 -aryllithium compounds such as (C 13 H 9 Li) 2 and {FeX 2 Li[RN(SiMe 2 )] 2 O} 2 [14]. Similarly as shown in 3, the azaallyl in 4 was also delocalized with C(1)-C (14) coordinated arene ring showed the slightly enlarged C-C distances 1.399 Å, indicating the effective coordination of η 6 -aryl groups [14,[27][28][29].…”

“…The reaction of Li 2 {η 5 -C 5 H 4 Si(Me) 2 C(H)SiMe 3 } with t BuCN produced a silyl-bridged cyclopentadienyl-azaallyl-lithium [12]. Therefore there were various coordination within lithioorganic complexes such as η 5 -fashion of cyclopentadienyl [12], indenyl and fluorenyl [13], η 3 -allyllic [10,13a], η 1 -allyllic [11] and a few η 6 -arene [14,15]. In this work, the reaction of 9-trimethylsilylfluorenyllithium with α-hydrogen-free nitriles produced three organolithium compounds, and showed the bonding features of ligands as η 3 -fluorenyl, η 3 -azaallyl, η 6 -arene and donating bonds.…”

Ge14Br8(PEt3)4: Ein Subhalogenidcluster des Germaniums

“…[7] [8,9] eine leere polyedrische Anordnung von 14 Germaniumatomen realisiert, was darauf hinweist, dass auch grçßere polyedrische Cluster ohne stabilisierendes Atom im Zentrum zugänglich sind, wodurch sich ein Zugang zu den bis jetzt unbekannten Germafullerenen andeutet. Weiterhin ähnelt die Anordnung der 12 Germaniumatome im Clusterkern des metalloiden Germaniumclusters {Ge 12 [FeCp-(CO) 2 ] 8 [FeCp(CO)] 2 }d erjenigen in der Hochdruckmodifikation Germanium(II). [10] Diese Ergebnisse zeigen, dass die Bildung von Metallen oder Halbmetallen ein äußerst komplexer Prozess ist, bei dem auch innerhalb eines einzelnen Clusters eine strukturelle Annäherung an verschiedene Festkçrpermodifikationen realisiert werden kann, wie im Falle des metalloiden Germaniumclusters Ge 18 [Si(SiMe 3 ) 3 ] 6 gezeigt wurde.…”