Bis-NHC chelate complexes of nickel(0) and platinum(0).
For a long time d(10)-ML2 fragments have been known for their potential to activate unreactive bonds by oxidative addition. In the development of more active species, two approaches have proven successful: the use of strong σ-donating ligands leading to electron-rich metal centers and the employment of chelating ligands resulting in a bent coordination geometry. Combining these two strategies, we synthesized bis-NHC chelate complexes of nickel(0) and platinum(0). Bis(1,5-cyclooctadiene)nickel(0) and -platinum(0) react with bisimidazolium salts, deprotonated in situ at room temperature, to yield tetrahedral or trigonal-planar bis-NHC chelate olefin complexes. The synthesis and characterization of these complexes as well as a first example of C-C bond activation with these systems are reported. Due to the enforced cis arrangement of two NHCs, these compounds should open interesting perspectives for bond-activation chemistry and catalysis.
Institute of Organic Chemistry, Ruprecht-Karls-University Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg (Germany).
Matthias
M
Brendel
Carolin
C
Braun
Frank
F
Rominger
Peter
P
Hofmann
carbene ligands; chelates; nickel; platinum