title: Self-assembly of artificial nucleobase 1H-benzimidazole-4,7-dione at the liquid/solid interface.
abstract: Self-assembly at the liquid/solid interface of an electrochemically active DNA nucleobase analogue, 1H-benzoimidazole-4,7-dione (Q), has been studied by means of scanning tunneling microscopy (STM). High-resolution STM images revealed the formation of well-ordered two-dimensional (2D) supramolecular nanostructures when the Q molecules are adsorbed onto the graphite surface from a 1-octanol solution. Detailed analysis shows that the observed 2D nanostructures are mainly dominated by hydrogen-bonded Q molecules. Since Q can be considered as a molecule mimicking the nucleobase guanine (G), which is known to form Watson-Crick base pairs with its complementary nucleobase cytosine (C), we have examined the binding ability of Q with C realized by available hydrogen-bonding sites on both Q and C molecules. Upon deposition of a mixture of Q and C molecules onto a graphite surface, one might expect that hydrogen-bonded QC dimers were observed in a new 2D self-assembled structure governed by inter- and intramolecular hydrogen-bonding interactions between Q and C molecules. However, our STM experiments showed that no well-ordered structures are formed and instead phase separation occurs where large-scale homodomains are formed consisting of the individual QQ and CC dimers. To gain further insight into the possible molecular arrangements of the Q and C nucleobases in the mixture phase, the high-resolution STM images are compared with the results from ab initio density functional theory (DFT) calculations.
authors.affiliation: Centre for DNA Nanotechnology, Department of Physics, Aarhus University, Denmark. wael@inano.dk
authors.forename: Wael
authors.initials: W
authors.lastname: Mamdouh
authors.forename: Ross E A
authors.initials: RE
authors.lastname: Kelly
authors.forename: Mingdong
authors.initials: M
authors.lastname: Dong
authors.forename: Mikkel F
authors.initials: MF
authors.lastname: Jacobsen
authors.forename: Elena E
authors.initials: EE
authors.lastname: Ferapontova
authors.forename: Lev N
authors.initials: LN
authors.lastname: Kantorovich
authors.forename: Kurt V
authors.initials: KV
authors.lastname: Gothelf
authors.forename: Flemming
authors.initials: F
authors.lastname: Besenbacher
mesh_terms: D001562:Benzimidazoles / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry*; D016252:Microscopy, Scanning Tunneling; D049329:Nanostructures / Q000737:chemistry; D011789:Quantum Theory
chemical_list: D001562:Benzimidazoles; D006147:Guanine; C542784:1H-benzimidazole-4,7-dione; C031000:benzimidazole