Site-selection and recognition of aromatic carboxylic acid in response to coronene and pyridine derivative

The self-assembled structures of H_(3) BDA molecule with multiple meta-dicarboxylic groups and their stim-ulus responses to the guest molecules(COR and T4PT)are thoroughly investigated by scanning tunneling microscopy(STM).STM observations display that two kinds of nanostructures are fabricated by H3 BDA molecules through intermolecular hydrogen bonds,in which a linear structure is formed at a higher con-centration and a flower-like structure is obtained at a lower concentration.After the addition of COR and T4PT,H_(3) BDA appears different responsiveness resulting in different co-assembled structures,respectively.The linear structure is regulated into a flower-like structure by COR and COR molecules are trapped in the cavities.When the pyridine derivative(T4PT)is introduced,a new bicomponent porous structure emerges via the hydrogen bond formed between the carboxyl group and the pyridine.Furthermore,the deposition of additional COR to the H_(3) BDA/T4PT system results in the breakdown of the porous structure and the generation of H_(3) BDA/COR host-guest system.Combined with density functional theory(DFT)calculations and molecular dynamics(MD)simulations,the transformation phenomenon of bi-component nanostruc-ture induced by guest molecules is formulated.The results are expected to understand the modification effect of guest molecules on the host network,which is of great significance for the design and construc-tion of multi-component nanostructures and crystal engineering.