Abundant two-dimensional hydrogen-bonded co-assemblies of tetracarboxylic acid derivatives and pyridine derivatives studied by means of scanning tunneling microscopy

• Published in: New journal of chemistry 2023-10, Vol.47 (38), p.181-1817
• Main Authors: Lei, Peng, Luo, Wendi, Deng, Ke, Tu, Bin, Xiao, Xunwen, Fang, Qiaojun, Wang, Chen, Zeng, Qingdao
• Format: Article
• Language: English
• Subjects: Acids; Assemblies; Carboxyl group; Carboxylic acids; Density functional theory; Hydrogen bonding; Hydrogen bonds; Microscopy; Nanostructure; Pyridines; Quadrilaterals; Scanning tunneling microscopy; Self-assembly
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d3nj01682j

In this study, the abundant co-assemblies of three rigid pyridine derivatives (PDPD, BisPY and TPYB) and tetracarboxylic acid (H 4 BTY) are constructed and explored with the assistance of scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. By examining the self-assembly of H 4 BTY and co-assemblies of H 4 BTY and three different pyridine derivatives, the driving mechanisms of those assemblies are contemplated. Firstly, H 4 BTY self-assembles into a quadrilateral structure at the interface and then the self-assembled structure exhibits various responses when different pyridine derivatives (PDPD, BisPY and TPYB) are added. The bipyridine PDPD molecule with a shorter conjugate length constructs a classical acid-pyridine-acid two-dimensional co-assembly structure by forming O-H N hydrogen bonds. As for the longer bipyridine molecule BisPY, a novel acid-pyridine-pyridine-acid two-dimensional co-assembly structure is formed at the interface via O-H N hydrogen bonds and π-π interaction. With regard to the tripyridine molecule TPYB, three pyridine groups interact with a carboxyl group or a phenyl group, and finally three different co-assemblies are formed at the interface. Such structural regulatory behaviors may be ascribed to the different intermolecular and intramolecular interactions of co-assemblies. The regulations of pyridine derivatives on carboxylic acid assembly structures could be advantageous to the construction of functional nanostructures and the explorations of co-assembly mechanisms in molecular nanostructures. Through the introduction of different pyridine derivatives into carboxylic acid self-assembly structures, abundant co-assembly structures were constructed by converting the O-H O hydrogen bond to O-H N or C-H N hydrogen bonds.