"Hummingbird" behaviour of N-heterocyclic carbenes stabilises out-of-plane bonding of AuCl and CuCl units.
Chemistry
; 21(31): 10997-1000, 2015 Jul 27.
Article
em En
| MEDLINE
| ID: mdl-26130507
ABSTRACT
An N-heterocyclic carbene substituted by two expanded 9-ethyl-9-fluorenyl groups was shown to bind an AuCl unit in an unusual manner, namely with the AuX rod sitting out of the plane defined by the heterocyclic carbene unit. As shown by X-ray studies and DFT calculations, the observed large pitch angle (21°) arises from an easy displacement of the gold(I) atom away from the carbene lone-pair axis, combined with the stabilisation provided by weak CHâ
â
â
Au interactions involving aliphatic and aromatic H atoms of the NHC wingtips. Weak, intermolecular Clâ
â
â
H bonds are likely to cooperate with the Hâ
â
â
Au interactions to stabilise the out-of-plane conformation. A general belief until now was that tilt angles in NHC complexes arise mainly from steric effects within the first coordination sphere.
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Base de dados:
MEDLINE
Idioma:
En
Revista:
Chemistry
Assunto da revista:
QUIMICA
Ano de publicação:
2015
Tipo de documento:
Article