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Title: Characterization of one-dimensional molecular chains of 4,4′-biphenyl diisocyanide on Au(111) by scanning tunneling microscopy

The morphology and electronic structure of vapor deposited 4,4′-biphenyldiisocyanide (BPDI) on a Au(111) surface were investigated using variable-temperature scanning tunneling microscopy. When deposited at room temperature, BPDI molecules form one-dimensional molecular chains similar to that recently observed for the structurally related 1,4-phenyl diisocyanide (PDI). Compared to PDI, the longer periodicity for the BPDI molecular chains is consistent with the addition of a second phenyl ring and supports a structural model in which the BPDI molecules lie parallel to the surface and interconnected by Au-adatoms. The molecular chains are mostly aligned along the [11{sup -}0] direction of the Au(111) substrate, but exhibit frequent changes in angle that are consistent with directions between fcc and hcp three-fold hollow sites. Dispersion-corrected density functional theory calculations for one-dimensional chains of BPDI molecules bound end-to-end via their isocyanide groups to Au-adatoms reproduce the observed periodicity of the chains and show that this morphology is energetically favored over upright binding with one free —NC group. The spatially resolved conductance (dI/dV) map for BPDI on Au(111) exhibits a feature centered at −0.67 eV below the Fermi level which are delocalized along the chain with maxima at the Au-adatom and biphenyl positions. This occupied resonant feature is closemore » to that previously observed for the PDI in both photoemission and conductance measurements and is attributed to an occupied interfacial state resulting from BPDI-Au interactions.« less
Authors:
 [1] ;  [2] ; ;  [3] ;  [4] ;  [1] ;  [5]
  1. Department of Chemistry, Stony Brook University, Stony Brook, New York 11794 (United States)
  2. Computational Science Center, Brookhaven National Laboratory, Upton, New York 11973 (United States)
  3. Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973 (United States)
  4. Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)
  5. (United States)
Publication Date:
OSTI Identifier:
22415471
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 10; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BIPHENYL; COMPARATIVE EVALUATIONS; DENSITY FUNCTIONAL METHOD; ELECTRONIC STRUCTURE; EV RANGE; FCC LATTICES; FERMI LEVEL; HCP LATTICES; MOLECULES; MORPHOLOGY; ONE-DIMENSIONAL CALCULATIONS; PERIODICITY; PHOTOEMISSION; SCANNING TUNNELING MICROSCOPY; STRUCTURAL MODELS; SUBSTRATES; SURFACES; TEMPERATURE RANGE 0273-0400 K; VAPOR DEPOSITED COATINGS