title: Exploring the concept of aromaticity on complexes of a fourfold benzannulated cyclopentadienyl ligand.
abstract: The ligand dibenzo[c,g]fluorenide (Dbf(-)), combines a cyclopentadienide ligand and 1,1'-binaphthyl fragment in one molecule. Preliminary investigations confirmed the special electronic situation in this 6pi-electron donor by way of a series of novel transition-metal complexes. Herein, the electron delocalization was investigated in detail by means of DFT calculations in combination with calculations on the nucleus-independent chemical shifts (NICS). These results clearly prove that the Dbf(-) ion gains the largest aromatic stabilization among all benzannulated fluorenides, and there are two almost olefinic C=C bonds in this structure. These bonds undergo cyclopropanation when treated with ZnEt(2) and ClCH(2)I in a modified Simmons-Smith reaction.
authors: Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Strasse Geb. 54, 67663 Kaiserslautern, Germany.
authors: Frank
authors: F
authors: Pammer
authors: Yu
authors: Y
authors: Sun
authors: Daniel
authors: D
authors: Weismann
authors: Helmut
authors: H
authors: Sitzmann
authors: Werner R
authors: WR
authors: Thiel