Complexes featuring N-heterocyclic carbenes with bowl-shaped wingtips

Publication date: Available online 27 February 2019Source: Comptes Rendus ChimieAuthor(s): Hamzé Almallah, Mélodie Nos, Virgile Ayzac, Eric Brenner, Dominique Matt, Christophe Gourlaouen, Mohamad Jahjah, Akram HijaziAbstractThree imidazolium salts having their two N-substituents equipped with remote calix[4]arenyl termini have been synthesised and converted into N-heterocyclic carbene (NHC) complexes of the type [PdCl2(NHC)(pyridine)]. An X-ray diffraction study carried out for one of the complexes, namely, trans-[1,3-bis(4-{25,26,27,28-tetrapropyloxycalix[4]aren-5-yl}phenyl)imidazol-2-ylidene](pyridine)palladium(II) dichloride, revealed that in the solid state the complex crystallises as a self-assembled dimer, its components being held together by dispersion forces involving the polyphenoxy units, the pyridine ligands and phenylene rings. This structure provides a new example of the diversity of interactions that may occur in NHC complexes of catalytic relevance, which are thus not limited to intramolecular ones. There was no spectroscopic indication that such interactions also occur in solution.RésuméTrois sels d'imidazolium ayant leurs atomes d'azote substitués par des groupes arylcalixarényle ont été préparés et utilisés pour la synthèse de complexes de type [PdCl2(NHC)(pyridine)] (NHC = carbène N-hétérocyclique). L'analyse par diffraction des rayons X du complexe trans-[1,3-bis(4-{25,26,27,28-tétrapropyloxycalix [4]arèn-5-yl}phényl)imidazol-2-ylidène]...

Source: Comptes Rendus Chimie - February 28, 2019 Category: Chemistry Source Type: research