Experimental and theoretical study on cation–π interaction of Ag+ with [6]helicene

Abstract

By employing electrospray ionization mass spectrometry, it was proven experimentally that the [6]helicene–Ag+ complex (i.e., [Ag(C26H16)]+) exists in the gas phase. Further, applying quantum mechanical DFT calculations, the most probable structure of this cationic complex [Ag(C26H16)]+ was derived. Finally, in the solid state, the complex [6]helicene–silver triflate–monohydrate (i.e., C26H16–AgCF3SO3–H2O), crystallizing in the monoclinic system with the centro-symmetric P21/c space group, was prepared and analyzed. The characteristic feature of this complex packing in the solid state is the formation of the separated [6]helicene and silver triflate domains. In both of these binding modes, the investigated [6]helicene ligand functions as a molecular tweezer for the univalent silver cation.