These achievements together with the progress in computational methods [24] have stimulated molecular designs with new functionalities. In the present study, the effect of quantum interference on electron transport through a single benzene ring is explored by considering two specifically designed oligo(3)-phenylenevinylene SB202190 nmr (OPV3) derivatives in which the central benzene ring is coupled either in a para or meta configuration. Details concerning the synthetic procedure for the selleck inhibitor para-OPV3 have been previously reported [25] while for the meta-OPV3 are given in the Additional file 1. The low-bias

conductance of single-molecule junctions bonded via thiol groups to gold electrodes is measured and statistically analyzed using the mechanically controlled break-junction

(MCBJ) technique and conductance histograms. In a recent work [26], we reported signatures of quantum interference effects through a benzene ring coupled to thienyl anchoring groups by ethynyl spacers. The observation of interference effects in both systems indicates that the coupling to the central ABT-737 order benzene ring determines the occurrence of quantum interference effects, while the spacers and anchoring groups slightly tune the conductance through the molecular junction. Methods We explore quantum interference effects in charge transport through a single benzene ring by measuring the low-bias conductance of two different OPV3

molecules depicted in Figure 1a. The molecules consist of a single benzene ring coupled in a para or meta configuration to vinyl spacers and terminated by acetyl-protected thiol anchoring groups. The vinyl spacers provide some distance between the gold electrodes and the central benzene ring to prevent the quenching of 3-oxoacyl-(acyl-carrier-protein) reductase the interference effects caused by the strong hybridization between the molecular orbitals and the continuous density of states of the electrodes. The thiol anchoring groups, providing a covalent linkage to the electrodes, are the most common choice to form single-molecule junctions. The acetyl protection group is frequently introduced in conjugated molecules to avoid the oxidative polymerization of free thiols. These acetyl groups are cleaved spontaneously at the gold surfaces or upon exposure to an acidic or a basic environment [27, 28]. Figure 1 Structures of OPV3-based molecules and MCBJ setup. (a) Structures of OPV3-based molecules studied in this work. The para- (blue) and meta- (red) coupled benzene rings are connected to acetyl-protected thiols (green) by vinyl spacers (black). (b) Scheme of the mechanically controlled break-junction (MCBJ) setup. Inset, false-color scanning electron micrograph of a MCBJ device. The low-bias conductance and formation of single-molecule junctions were studied using the MCBJ technique.