Photo-Responsiveness And Assembly Dynamics Of Supramolecular Systems

Supramolecular chemistry is an emerging subject based on non-covalent bond interaction between molecules.Supramolecular chirality is a very important branch of supramolecular chemistry,which has been widely concerned and deeply studied due to its potential application in biological imaging sensing chiral catalytic optical anti-counterfeiting and other aspects.This kind of supramolecular chirality is different from traditional molecular chirality.It is based on the chirality of a single molecule,and it superimposes,amplifies and transmits the chirality of small molecules.The driving force influencing the formation of this assembly is also non-covalent bond interaction.Common non-covalent bond interactions include-stacking interactions,metal-metal interactions,hydrogen bond interactions,host-guest interactions,and so on.Because these forces are dynamically reversible,the resulting assembly is sensitive to external factors such as temperature,concentration,pH,and solvents.On the other hand,our research group has developed a series of chiral supramolecular assembly monomers based on the platinyl group,so the first part of this paper is to explore the influence of solvents on the chirality of supramolecular assembly.In addition,the self-assembly process of monomer in solution is affected by both thermodynamic and kinetic factors,and the combined action of the two factors tends to complicate the self-assembly process,resulting in the diversity of the assembly.Based on this,this paper is mainly divided into the following two parts:In the first part,we investigate the supramolecular polymerization of monomer based on platinyl anthracene in two different types of nonpolar solvents(linear solvents and cyclic solvents).Self-assembly process can be monitored by the temperature-dependent and solvent-dependent CD signal,the thermodynamic parameters obtained by fitting the relevant data can prove the stability of assembly in different solvents.What's more,photo-responsiveness of the monomer confirms that Supramolecular polymer is more stable in the liner solvents than in the cyclic solvents.In the second part,We have successfully designed a noval monomer connection element on the basis of Platinum(?)acetylene.And the new complexes give rise to the formation of two different supramolecular fibers of opposite chirality by changing the rate of cooling,including P type and M type,where,P-type is a dynamical metastable product,and it it can spontaneously translated into M-type.This provides a new way to study the assembly kinetics of monomer based on the platinyl molecule.In addition,the PR'3 ligands of the monomer(S)-1 have less steric hindrance,but it can not be translated into the formation of supramolecular fibers,which needs further study.