A first structural and theoretical comparison of pyridinylidene-type rNHC (remote N-heterocyclic carbene) and NHC complexes of Ni(II) obtained by oxidative substitution.
A series of cationic pyridinylidene and quinolinylidene complexes of chlorobis(triphenylphosphine)-nickel(II) were prepared by oxidative substitution of Ni(PPh3)4 with methylated chloropyridines or chloroquinolines. NMR as well as X-ray crystallographic studies confirmed the trans arrangement of the two phosphines in the products. Calculations, using suitable model compounds at the BP86/TZVP level, clearly differentiate between a standard imidazolylidene complex and new complexes of the NHC-type on the one hand, and new complexes classified as rNHC-types-with the heteroatom distant from the carbene carbon-on the other. The latter form significantly stronger bonds-mainly of an electrostatic nature-with the metal.
Department of Chemistry, Technische Universität München, Lichtenbergstr., 4, 85747, Garching, Germany.
Sabine K
SK
Schneider
Gerrit R
GR
Julius
Christoph
C
Loschen
Helgard G
HG
Raubenheimer
Gernot
G
Frenking
Wolfgang A
WA
Herrmann