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

Journal Article · Sat Mar 14 00:00:00 EDT 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4906046· OSTI ID:22415471

Zhou, Jing ^[1]; Li, Yan ^[2]; Zahl, Percy; Sutter, Peter ^[3]; Stacchiola, Dario J. ^[4]; White, Michael G. ^[1]

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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)

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 close 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.

• OSTI ID: 22415471
• Journal Information: Journal of Chemical Physics, Vol. 142, Issue 10; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

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