Jump to main content
Jump to site search


Square Planar Gold(III) bis-(1,1’-dimethyl-3,3’-methylene-diimidazol-2,2’-diylidene) Trication as Efficient and Selective Receptor Towards Halogen Anions: Cooperative Effect of Au∙∙∙X and X∙∙∙HC Interactions

Abstract

Treatment of the tricationic gold(III) [Au(MeImCH2ImMe)2](PF6)3 complex 1-3PF6 (Im = imidazol-2-ylidene) with excess halides affords complexes 1-3X (X = Cl, Br, I), resulting from counter anion PF6-/X- exchange. The 1H chemical shift of the CH3 groups and particularly of the CH2 linker in DMSO-d6 are different in the three complexes, thus suggesting selective X•••HC interactions. Complex 13+ can be therefore used as halide sensor in DMSO and water. The host-guest interaction between the tricationic gold(III) complex and the halides Cl-, Br- and I- in solution and in the solid state has been investigated by means of NMR titration experiments, DFT calculations and X-ray structure analysis. The electrostatic interaction between the halides and the triple formal positive charge on the metal centre, together with the CH•••X hydrogen bonding between NHC ligand and halides contributes to forming stable supramolecular aggregates in solution and in the solid state. The behaviour of the 13+ complex is strongly influenced by the nature of the solvent. Formation of the 1:1 and 1:2 species (1X2+ and 1X2+) is observed in DMSO-d6, while only the 1:1 aggregates (1X2+) are observed in D2O (X = Cl, Br, I). Moreover, the selectivity towards the various halides is reversed in the two solvents, being in the order Cl->Br->I- in DMSO-d6 and I->Br->Cl- in D2O. The formation constants of the species 1X2+ and 1X2+ in DMSO and 1X2+ in water have been determined by fitting the NMR titration curves using the PITMAP computer program.

Back to tab navigation

Supplementary files

Publication details

The article was received on 29 Sep 2017, accepted on 28 Nov 2017 and first published on 05 Dec 2017


Article type: Paper
DOI: 10.1039/C7DT03672H
Citation: Dalton Trans., 2017, Accepted Manuscript
  •   Request permissions

    Square Planar Gold(III) bis-(1,1’-dimethyl-3,3’-methylene-diimidazol-2,2’-diylidene) Trication as Efficient and Selective Receptor Towards Halogen Anions: Cooperative Effect of Au∙∙∙X and X∙∙∙HC Interactions

    M. Baron, A. Dall'Anese, C. Tubaro, L. Orian, V. Di Marco, S. Bogialli, C. Graiff and M. Basato, Dalton Trans., 2017, Accepted Manuscript , DOI: 10.1039/C7DT03672H

Search articles by author

Spotlight

Advertisements