Cross-conjugation increases the conductance of meta-connected fluorenones.

Alanazy A, Leary E, Kobatake T, Sangtarash S, González MT, Jiang H-W, Bollinger GR, Agräit N, Sadeghi H, Grace I, Higgins SJ, Anderson HL
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et al

Charge transport is strongly suppressed by destructive quantum interference (DQI) in meta-connected 1,1'-biphenyl-containing molecules, resulting in low electrical conductance. Surprisingly, we have found that DQI is almost entirely overcome by adding a bridging carbonyl, to yield a cross-conjugated fluorenone. This contrasts with other π-systems, such as para-connected anthraquinone, where cross-conjugation results in low conductance.