Dynamic Covalent Reactions In The Study Of π-stacking And Construction Of Complex Systems

Dynamic covalent chemistry has the properties of self-adaptiveness and stimuli-responsiveness,and has been widely used in constructing organic frameworks,modifying nanomaterials,and regulating biological molecules.In addition,dynamic covalent bonds combine the reversibility of supramolecular interactions with the stability of covalent bonds,making them a powerful tool for studying non-covalent interactions and complex systems.1,π interactions are widely found in chemistry,and therefore,it is of great significance to explore their nature and mechanism.This paper presents orthogonal assembly of dynamic covalent bonds and π interactions for the study of substituent effects on π/π stacking.A novel reversible covalent reaction between 10-methylacridinium perchlorate and various primary amines was first developed.At the same time,the amine exchange experiments showed that the product derived from benzene-substituted amines was favored,and the π/π stacking was reveled playing a role in stabilizing the assembly.In Hammett’s linear free energy analysis,σm is positively correlated with the free energy of exchange.The additivity of free energy further supports the direct interaction model of substituent effects on π/π stacking.Finally,the introduction of chiral amines facilitated the amplification of circular dichroism signal throug π/π stacking within the orthogonal assembly.2.The field of systems chemistry is devoted to the construction of multi-component mixtures for mimicking biological systems,but effective control of complexity has been difficult to date.In this paper,a strategy of switchably orthogonal dynamic covalent chemistry was established to control complex dynamic reaction networks.Tautomeric 2-formylbenzenesulfonamide derivatives were used as building blocks to develop a general system for reversible covalent bonding of amines,alcohols,and thiols.By selecting the different reaction paths of the open/cyclic isomers and controlling the nucleophilicity,the switch between the assemblies incorporating amine and alcohol,alcohol and thiol,or amine and thiol,was realized.The selective control of dynamic covalent reactions of amines,alcohols,and thiols,and the reversible interconversion between their respective assemblies were further accomplished in one vessel,thus achieving the switch between three types of dynamic covalent bonds.Based on the above studies,by taking advantage of varied affinity of 2-formylbenzenesulfonamide with different substituents toward each type of nucleophile,the switchable orthogonality was combined with the differential reactivity of sulfonamides,and more complex multi-component chemical systems were constructed.In short,the originality and diversity of our strategies would facilitate their application in many aspects of chemical research.