Premium
Exploring the Concept of Aromaticity on Complexes of a Fourfold Benzannulated Cyclopentadienyl Ligand
Author(s) -
Pammer Frank,
Sun Yu,
Weismann Daniel,
Sitzmann Helmut,
Thiel Werner R.
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200902003
Subject(s) - delocalized electron , aromaticity , chemistry , cyclopentadienyl complex , ligand (biochemistry) , molecule , computational chemistry , electron delocalization , stereochemistry , transition metal , crystallography , organic chemistry , biochemistry , receptor , catalysis
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 6π‐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 CC bonds in this structure. These bonds undergo cyclopropanation when treated with ZnEt 2 and ClCH 2 I in a modified Simmons–Smith reaction.