Bimetallic Gold(I) Complexes with Ethynyl-Helicene and Bis-Phosphole Ligands: Understanding the Role of Aurophilic Interactions in their Chiroptical Properties

Abstract : Monometallic gold(I)-alkynyl-helicene complexes (1a,b,) and bimetallic gold(I)-alkynyl-helicene architectures featuring the presence (2a,b) or absence (3a,b) of aurophillic intramolecular interactions were prepared by using different types of phosphole ligands (mono-phosphole L1 or bis-phospholes L2,3). The influence of the Au(I) d10-metal center(s) on the electronic, photophysical and chiroptical properties of these unprecedented phosphole-gold(I)-alkynyl-helicene complexes were examined. Experimental and theoretical results highlight the importance of ligand-to-ligand-type charge transfers and the strong effect of presence or absence of Au(I)-Au(I) interactions in 2a,b.