In recent years, with the advancement of techniques for manipulating individual molecules, electronic devices based on single molecules have been considered one of the most promising candidates for today’s silicon-based devices both for their novel physical properties and potential for device applications [1,2], such as negative differential resistance (NDR), switches, latches and rectifiers. β-Dicarbonyl compounds, with at least one α-hydrogen, are capable to display a keto–enol tautomerism as illustrated in Fig. 1. The cis-enol forms of β-dicarbonyl compounds are engaged in an IHB system and stabilized in a six-membered chelated ring. Using nonequilibrium Green’s function formalism combined first-principles density functional theory; we study the transport properties of dimethyl 3,5-heptane as a molecular switch. The I–V characteristics, differential conductance, on-off ratio, electronic transmission coefficients, HOMO–LUMO gaps and effect of electrode materials Y (Y=Au, Ag, and Pt) on electronic transport corresponding to the keto and enol forms through the molecular devices are discussed in detail. It was found that the best switching behavior performance happens in the gold electrode. Based on data when the enol form transforms to the keto form, there is a switch from on state to the off state (low resistance switches to high resistance).

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