title: Breakdown of interference rules in azulene, a nonalternant hydrocarbon.
abstract: We have designed and synthesized five azulene derivatives containing gold-binding groups at different points of connectivity within the azulene core to probe the effects of quantum interference through single-molecule conductance measurements. We compare conducting paths through the 5-membered ring, 7-membered ring, and across the long axis of azulene. We find that changing the points of connectivity in the azulene impacts the optical properties (as determined from UV-vis absorption spectra) and the conductivity. Importantly, we show here that simple models cannot be used to predict quantum interference characteristics of nonalternant hydrocarbons. As an exemplary case, we show that azulene derivatives that are predicted to exhibit destructive interference based on widely accepted atom-counting models show a significant conductance at low biases. Although simple models to predict the low-bias conductance do not hold with all azulene derivatives, we demonstrate that the measured conductance trend for all molecules studied actually agrees with predictions based on the more complete GW calculations for model systems.
authors.affiliation: Department of Chemistry and ‡Department of Applied Physics and Applied Mathematics, Columbia University , New York, New York 10027, United States.
authors.forename: Jianlong
authors.initials: J
authors.lastname: Xia
authors.forename: Brian
authors.initials: B
authors.lastname: Capozzi
authors.forename: Sujun
authors.initials: S
authors.lastname: Wei
authors.forename: Mikkel
authors.initials: M
authors.lastname: Strange
authors.forename: Arunabh
authors.initials: A
authors.lastname: Batra
authors.forename: Jose R
authors.initials: JR
authors.lastname: Moreno
authors.forename: Roey J
authors.initials: RJ
authors.lastname: Amir
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Amir
authors.forename: Gemma C
authors.initials: GC
authors.lastname: Solomon
authors.forename: Latha
authors.initials: L
authors.lastname: Venkataraman
authors.forename: Luis M
authors.initials: LM
authors.lastname: Campos
mesh_terms: D052176:Azulenes / Q000138:chemical synthesis / Q000737:chemistry*; D006046:Gold / Q000737:chemistry; D006838:Hydrocarbons / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D011789:Quantum Theory
chemical_list: D052176:Azulenes; D006838:Hydrocarbons; D006046:Gold; C005525:azulene