Self-assembly Of Cucurbiturils With Benzotriazole And Viologen Molecules

Cucurbit[n]urils(CB[n])is the fourth generation of macrocyclic molecule developed after crown ethers,cyclodextrins,calixarenes.Because of its special structure and properties,it is highly valued by scholars at home and abroad in many fields.The supramolecular assembly based on cucurbit[n]urils has broad application prospects in biomedicine,analytical science and material science.Based on the research literature of cucurbit[n]urils,we used CB[8],TMeCB[6],CB[7]and ns-CB[10]as research objects,and investigated the supramolecular self-assembly between four host molecules and different guest molecules,mainly including the following contents:We synthesized three guest molecules with different alkyl chain lengths(Lc12,Lc8,Lc4).Different supramolecular self-assembly between 1-dodecyl-3carboxymethylbenzotriazole(Lc12),1-octyl-3-carboxymethylbenzotriazole(Lc8)and 1-butyl-3-carboxymethylbenzotriazole(Lc4)in the solid state and in aqueous solution has been investigated.For Lc12@CB[8]system,1:1 host-guest complexes were formed in aqueous solution and 2:2 host-guest complexes were formed in the solid state,and the dodecyl chains adopted contorted conformations when bound to CB[8]molecules.For Lc8@CB[8]system,1:1 host-guest complexes were formed both in aqueous solution and in solid state,and the alkyl chain and benzotriazole moiety of guest Lc8 were both squeezed into the cavity of the CB[8].The Lc4@CB[8]system was similar to Lc8@CB[8],1:1 host-guest complexes were formed in aqueous solution,the alkyl chain and benzotriazole moiety of guest Lc4 were encapsulated into the cavity of the CB[8].Isothermal titrations in water afforded high apparent association constants for complexes Lc12@CB[8],Lc8@CB[8]and Lc4@CB[8].This research may provide a sight into designing novel molecular machines.We designed and synthesized four 4,4’-pyridine derivatives(M1,M2,M3,G1)and a tetrahedral molecule(T1),and systematically studied the host-guest interaction between five guest molecules and three host molecules(TMeCB[6],CB[7],ns-CB[10]).We used nor-seco-cucurbit[10]uril(ns-CB[10])based ternary complexation to construct[5]rotaxane,linear supramolecular dynamic rotaxane polymers and cubic 3D misaligned supramolecular organic framework.A[5]rotaxane was constructed by ns-CB[10],TMeCB[6]and M2,Ns-CB[10],CB[7]and M3 self-assembled into a linear supramolecular dynamic rotaxane polymer.Ns-CB[10]and tetracationic tetrahedral monomer T1 formed a three-dimensional misaligned supramolecular organic framework.The above results demonstrated that ns-CB[10]-based ternary complexation is a versatile platform to build various supramolecular systems.