La(OTf)3-mediated self-organization of guanosine with an alkynyl-Au(I)PPh3 moiety to induce Au(I)-Au(I) interactions

A bioorganometallic compound GPhAuPPh(3) composed of the guanosine and alkynyl-Au(I)PPh3 moieties was prepared. The self-assembly properties in both the absence and presence of KPF6 or La(OTf)(3) were studied by NMR, UV-vis, CD and fluorescence measurements. When monovalent KPF6 was added, the expected octamer was formed without any Au(I)-Au(I) interactions. This is due to the presence of the bulky phosphine moiety that makes the Au(I) moieties far away each other. In contrast, in the presence of trivalent La(OTf)(3), a more closely stacked octamer was obtained than in the presence of KPF6, leading to Au(I)-Au(I) interactions.