Ligand conformation and cross-linkage While it is well-known that alkanethiols form tilted arrangements on Au(111) surfaces, where the tilt angle and the ordering of the SAMs depend, among other things, on the tail groups of the ligands, the ligand arrangement in cross-linked GNP assemblies is less investigated. It is known that the interparticle distance of GNPs in assemblies is lower than a fully extended alkanedithiol ligand. For example, an interparticle distance of 1.0 ± 0.2 nm was measured for 5 nm large GNPs cross-linked with 1,9-nonanedithiol by Leibowitz et al., whereas the fully extended ligand would be 1.5 nm long. They argue that the ligands remained in an all-trans conformation but adapted a tilted arrangement, similar to that in SAMs, which reduces the interparticle distance. On the other hand, Yeh et al. also found linkers with gauche conformations, where the end-toend distance of the dithiols was significantly lower than that of the tilted all-trans linkers.