Self-assembly of artificial nucleobase 1H-benzimidazole-4,7-dione at the liquid/solid interface.
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.
Mamdouh
Wael
W
Centre for DNA Nanotechnology, Department of Physics, Aarhus University, Denmark. wael@inano.dk
Kelly
Ross E A
RE
Dong
Mingdong
M
Jacobsen
Mikkel F
MF
Ferapontova
Elena E
EE
Kantorovich
Lev N
LN
Gothelf
Kurt V
KV
Besenbacher
Flemming
F
D001562:Benzimidazoles / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry*; D016252:Microscopy, Scanning Tunneling; D049329:Nanostructures / Q000737:chemistry; D011789:Quantum Theory
D001562:Benzimidazoles; D006147:Guanine; C542784:1H-benzimidazole-4,7-dione; C031000:benzimidazole