The lines in Fig. 8 are incorrectly labeled. The caption for Fig. 8 should read: "Fig. 8. DFT transmission curves. (a) The black curve shows the transmission coefficient for molecule b of Fig. 3. (b) The blue dashed curve shows the transmission coefficient for molecule a of Fig. 3.’’ Therefore, the first two paragraphs of Section III should read: "So far the discussion has focused on tight-binding representations of the molecules shown in Fig. 7. For molecules (a and b) containing two carbonyl groups, Fig. 8 shows DFT results for the transmission coefficients (see Methods for more details). In common with the tight binding results of Fig. 4, both a and b show alternating destructive interference features. In the case of a, such a feature occurs between the LUMO and LUMO+1, whereas in the case of b, they occur between the HOMO and LUMO and between LUMO+2 and LUMO+3. On the other hand for both molecules, destructive interference features appear near E = -2.4 eV, which are almost independent of connectivity, signaling the presence of a Fano resonance.’’ The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.