Chiral Ag(i) and Pt(ii) complexes of ditopic NHC ligands: synthesis, structural and spectroscopic properties

Paul Marshall,Samantha K Callear,Ian A Fallis,Simon J Coles,William Clegg,Robert L Jenkins,Athanasia Dervisi,Ross W Harrington

doi:10.1039/c2dt31740k

Paul Marshall, Samantha K Callear + Show 6 more

Open Access

https://doi.org/10.1039/c2dt31740k

Copy DOI

Abstract

The butyl and isopropyl derivatives (4I, 5Br) of chiral pool derived bis-imidazolium dehydrohexitol salts have been prepared. The ditopic N-heterocyclic carbenes 4 and 5 form dinuclear Ag(I) and Pt(II) complexes. All compounds were fully characterised by multinuclear NMR spectroscopy. The bis-imidazolium salt 4I and platinum complexes cis-[Pt(2)(μ-2)(dmso)(2)Cl(4)] and cis-[Pt(2)(μ-4)(dmso)(2)Cl(4)] were characterised by X-ray crystallography. In the case of the Pt(II) complexes, the carbene ring is positioned in a sterically preferred orientation, approximately perpendicular to the platinum coordination plane. The (1)H, (13)C, (15)N and (195)Pt NMR spectra of the platinum complexes show the presence of rotamers due to hindered rotation about the carbene-metal bond.

Highlights

IntroductionN-Heterocyclic carbene (NHC) ligands and their transition metal complexes have established themselves as a cornerstone of modern coordination chemistry and are used in a wide range of applications
The 1H, 13C, 15N and 195Pt NMR spectra of the platinum complexes show the presence of rotamers due to hindered rotation about the carbene–metal bond
N-Heterocyclic carbene (NHC) ligands and their transition metal complexes have established themselves as a cornerstone of modern coordination chemistry and are used in a wide range of applications

Summary

Introduction

N-Heterocyclic carbene (NHC) ligands and their transition metal complexes have established themselves as a cornerstone of modern coordination chemistry and are used in a wide range of applications. Silver(I) carbenes are extensively used as ligand transfer agents for the majority of imidazolium and other azolium salts, forming a part of a convenient, and sometimes the only, route for the synthesis of metal carbene complexes.[9] Ag(I)–NHC complexes have found many medicinal applications, mainly due to their activity as antimicrobials.[10] Other potential uses include high-end materials applications, such as luminescent chemosensors.[11] Silver–carbene complexes are structurally diverse, displaying a broad range of coordination motifs, ranging from simple two-coordinate linear molecules9e,12 to helicates,[13] polymers,[14] rings,[15] cages[16] and clusters.[17].

Discussion

Conclusions