Isolating individual components of nanoscale architectures comprised of thin films or nanostructures, without significantly impacting their functionalities, is a critical challenge in micro- and nano-scale device fabrication. One example that illustrates this challenge is seen in Cu interconnect structures for nanometer devices. These devices use interfacial barrier nanolayers to isolate copper layers from dielectric layers. However, currently used interfacial barrier layers are difficult to form as uniform and continuous layers, have limited effectiveness due to high defect densities and fast diffusion paths, and can potentially cause delamination between adjacent layers. This invention is directed to a sub-nanometer thick self-assembled molecular layer that is used as both a barrier layer and an adhesion layer between a copper layer and a substrate.