Issue 39, 2014

Ruthenium(ii) complexes of N-heterocyclic carbenes derived from imidazolium-linked cyclophanes

Abstract

The present work seeks to characterize, in the light of electronic structure calculations, an unusual metal–[(η1-NHC)2:(η6-arene)] bonding situation in a set of ruthenium(II) complexes containing the ortho-xylylene-linked-bis(NHC)cyclophane ligand (NHC-cyclophane) (1), which binds to the ruthenium center through two carbene carbons and one of the arene rings. The nature of ruthenium(II)–[(η1-NHC)2:(η6-arene)] bonding was investigated in the light of EDA-NOCV, NBO and QTAIM analyses by adopting 1 as a model compound. The interplay between the ortho-cyclophane scaffold with different families of five-membered carbenes, such as imidazole, 1, triazole-based NHCs (Enders’ carbenes), 2, and P-heterocyclic carbenes (PHCs), 3, was investigated. The metal–[(η1-NHC)2:(η6-arene)] bonding situation was also extended to heavier analogues, such as N-heterocyclic silylenes (NHSi) and N-heterocyclic germylenes (NHGe), in order to address how the basicity of NHC, NHSi and NHGe is affected by the cyclophane framework. The results reveal that ruthenium(II)–[(η1-NHC)2:(η6-arene)] is more covalently than electrostatically bonded and that the degree of covalence is larger in PHCs than in NHCs or Enders’ carbenes. It is also revealed that the covalent character in the ruthenium(II)–[(η1-NHGe)2:(η6-arene)] and ruthenium(II)–[(η1-NHSi)2:(η6-arene)] bonds is larger than in ruthenium(II)–[(η1-NHC)2:(η6-arene)].

Graphical abstract: Ruthenium(ii) complexes of N-heterocyclic carbenes derived from imidazolium-linked cyclophanes

Supplementary files

Article information

Article type
Paper
Submitted
19 May 2014
Accepted
24 Jul 2014
First published
21 Aug 2014

Dalton Trans., 2014,43, 14710-14719

Author version available

Ruthenium(II) complexes of N-heterocyclic carbenes derived from imidazolium-linked cyclophanes

G. F. Caramori, L. C. Garcia, D. M. Andrada and G. Frenking, Dalton Trans., 2014, 43, 14710 DOI: 10.1039/C4DT01473A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements