On-Surface Synthesis of Adenine Oligomers via Ullmann Reaction

Organometallic polymers synthesized from prochiral molecules by a surface-assisted synthesis on Ag(111)

Organometallic polymers can be successfully synthesized on a Ag(111) surface via a surface-assisted synthesis by choosing prochiral 4,4'-dibromo-2,2'-bis(2-phenylethynyl)-1,1'-biphenyl (DBPB) molecules as the designed precursor. High-resolution scanning tunneling microscopy investigation reveals that prochiral molecules show chirality on a surface and can evolve into organometallic chains on the Ag(111) surface based on Ullmann coupling. Due to the special structural features of DBPB molecules, chiral selectivity will be lost in the organometallic polymers. This result may provide an important basis for selecting suitable precursors to fabricate chiral covalent nanostructures on a surface.

Two-dimensional self-assembled nanostructures of nucleobases and their related derivatives on Au(111)

The construction of two-dimensional (2D) self-assembled nanostructures has been one of the considerably interesting areas of on-surface chemistry in the past few decades, and has benefited from the rapid development and improvement of scanning probe microscopy techniques. In this research field, many attempts have been made in the controllable fabrication of well-ordered and multifunctional surface nanostructures, which attracted interest because of the prospect for artificial design of functional molecular nanodevices. DNA and RNA are considered to be programmable self-assembly systems and it is possible to use their base sequences to encode instructions for assembly in a predetermined fashion at the nanometer scale. As important constituents of nucleic acids, nucleobases, with intrinsic functional groups for hydrogen bonding, coordination bonding, and electrostatic interactions, can be employed as a potential system for the versatile construction of various biomolecular nanostructures, which may be used to structure the self-assembly of DNA-based artificial molecular constructions and play an important role in novel biosensors based on surface functionalization. In this article, we will review the recent progress of on-surface self-assembly of nucleobases and their derivatives together with different reactants (e.g., metals, halogens, salts and water), and as a result, various 2D surface nanostructures are summarized.