Conductance across a metal|molecule|metal junction is strongly influenced by the molecule–substrate contacts, and for a given molecular structure, multiple conductance values are frequently observed and ascribed to distinct binding modes of the contact at each of the molecular termini. Conjugated molecules containing a trimethylsilylethynyl terminus, –CCSiMe₃ give exclusively a single conductance value in I(s) measurements on gold substrates, the value of which is similar to that observed for the same molecular backbone with thiol and amine based contacting groups when bound to under-coordinated surface sites.

The compounds and complexes 1,4‐C₆H₄(C≡C‐cyclo‐3‐C₄H₃S)₂ (2), trans‐[Pt(C≡C‐cyclo‐3‐C₄H₃S)₂(PEt₃)₂] (3), trans‐[Ru(C≡C‐cyclo‐3‐C₄H₃S)₂(dppe)₂] (4; dppe=1,2‐bis(diphenylphosphino)ethane) and trans‐[Ru(C≡C‐cyclo‐3‐C₄H₃S)₂{P(OEt)₃}₄] (5) featuring the 3‐thienyl moiety as a surface contacting group for gold electrodes have been prepared, crystallographically characterised in the case of 3–5 and studied in metal|molecule|metal junctions by using both scanning tunnelling microscope break‐junction (STM‐BJ) and STM‐I(s) methods (measuring the tunnelling current (I) as a function of distance (s)). The compounds exhibit similar conductance profiles, with a low conductance feature being more readily identified by STM‐I(s) methods, and a higher feature by the STM‐BJ method. The lower conductance feature was further characterised by analysis using an unsupervised, automated multi‐parameter vector classification (MPVC) of the conductance traces. The combination of similarly structured HOMOs and non‐resonant tunnelling mechanism accounts for the remarkably similar conductance values across the chemically distinct members of the family 2–5.

Cancer therapy is constantly evolving, with a growing emphasis on targeted and efficient treatment options. In this context, graphene quantum dots (GQDs) have emerged as promising agents for precise drug and gene delivery due to their unique attributes, such as high surface area, photoluminescence, up-conversion photoluminescence, and biocompatibility. GQDs can damage cancer cells and exhibit intrinsic photothermal conversion and singlet oxygen generation efficiency under specific light irradiation, enhancing their effectiveness. They serve as direct therapeutic agents and versatile drug delivery platforms capable of being easily functionalized with various targeting molecules and therapeutic agents. However, challenges such as achieving uniform size and morphology, precise bandgap engineering, and scalability, along with minimizing cytotoxicity and the environmental impact of their production, must be addressed. Additionally, there is a need for a more comprehensive understanding of cellular mechanisms and drug release processes, as well as improved purification methods. Integrating GQDs into existing drug delivery systems enhances the efficacy of traditional treatments, offering more efficient and less invasive options for cancer patients. This review highlights the transformative potential of GQDs in cancer therapy while acknowledging the challenges that researchers must overcome for broader application.

A metal–molecule–GNP assembly has been fabricated using an acetylene-terminated phenylene–ethynylene molecular monolayer, namely 4-((4-((4-ethynylphenyl)ethynyl)phenyl)ethynyl)benzoic acid (HOPEA), sandwiched between a gold substrate bottom electrode and gold nanoparticle (GNP) top contact electrode. In the first stage of the fabrication process, a monolayer of directionally oriented (carboxylate-to-gold) HOPEA was formed onto the bottom electrode using the Langmuir–Blodgett (LB) technique. In the second stage, the gold-substrate supported monolayer was incubated in a solution of gold nanoparticles (GNPs), which resulted in covalent attachment of the GNPs on top of the film via an alkynyl carbon–Au σ-bond thereby creating the metallic top electrode. Adsorption of the GNPs to the organic LB film was confirmed by both UV-vis absorption spectroscopy and X-ray photoemission spectroscopy (XPS), whilst the contact angle showed changes in the physical properties of the film surface as a result of top-coating of the LB film with the GNPs. Importantly, surface-enhanced Raman scattering (SERS) confirmed the covalent attachment of the metal particles to the LB film by formation of Au–C σ-bonds via a heterolytic cleavage of the alkyne C–H bond. Electrical properties of these nascent metal–molecule–GNP assemblies were determined from I–V curves recorded with a conductive-AFM in the Peak Force Tunneling AFM (PF-TUNA™) mode. The I–V curves obtained from these structures rule out the formation of any significant number of short-circuits due to GNP penetration through the monolayer, suggesting that this strategy of self-assembly of GNPs to alkyne-terminated monolayers is an effective ‘soft’ procedure for the fabrication of molecular junctions without damaging the organic layer.