Synthesis, Derivatization, Self-assembly And Functional Properties Of Methyl Citrulline

Cucurbit[n]uril,Q[n]is another type of macrocyclic compound that emerged after the cyclodextrin,crown ether and calixarene in the field of supramolecular chemistry.It has two openning hydrophilic carbonyl ports and a hydrophobic cavity.At present,members of the Q[n]-family include Q[5],Q[6],Q[7],Q[8],Q[10],twisted Q[13-15]s,the Q[n]s with even polymerization degree have poor solubility in water and organic solvents.It limits the application and research of Q[n]-chemistry.Therefore,in order to improve the properties of the common Q[n]s,especially solubility,the main work of this paper is to synthesize and isolate a series of novel and soluble partial methyl0substituted Q[n]s.In this paper,methyl diglycol diether,common glycoluril and common glycoluril dimer were used as raw materials,and a series of patial methyl-substituted Q[n]s,including hexamethyl substituted cucurbit[6]uril Me₆Q[3,3],inverted hexamethyl substituted cucurbit[6]uril iMe₆Q[3,3],hexamethyl substituted cucurbit[7]uril HMeQ[7],tetramethyl substituted cucurbit[8]uril TMeQ[8]were successfully synthesized and isolated,and their properties were also investigated in detail.In this paper,Me₆Q[3,3]was used as raw material,photochemical oxidation and separation were carried out to obtain?OH?Me₆Q[3,3],?OH?₂Me₆Q[3,3],?OH?₃Me₆Q[3,3].Their structures were characterized by a series of methods,including nuclear magnetic resonance,infrared,X-ray single crystal diffractometry,and mass spectrometry.The experimental results show that allyl derivatization of the hydroxyl groups of the three hydroxylated Me₆Q[3,3]has been achieved in terms of chemical modification.This opens up a new way for the chemical controllable modification of Q[n]s,especially the alkyl substitution of Q[n]s,which can provide a new Q[n]-based supramolecular assembly system..Using Me₆Q[3,3]as raw materials,supramolecular assemblies with different porous structures were constructed in different solvents.The adsorption properties of these porous self-assembly entities on different dyes were studied,and the Me₆Q[3,3]-based fluorescent materials or sensors adsorbed on rhodamine,luciferin and pyrene were screened out.Further research shows that the fluorescence sensor formed by Me₆Q[3,3]-based assembly and rhodamine can identify diethyl ether and carbon tetrachloride by fluorescence quenching;the fluorescent sensor formed by Me₆Q[3,3]-based assembly and luciferin can identify methanol and ethanol by fluorescence enhancement.Thus,the preparation of these fluorescent materials broadens the application of Me₆Q[3,3].A new member of the inverted Q[n]s iMe₆Q[3,3]was synthesized by using methylglycolide diether and common glycoluril as raw materials.iMe₆Q[3,3]exhibits different solubility properties from iQ[6].It is not only soluble in aqueous solution,but also has good solubility in organic solvent?DMSO?.properties from iQ[6],and has good solubility not only in aqueous solution and organic solvent?DMSO?.This will broaden the application of inverted Q[n]s in Q[n]-based coordination chemistry,Q[n]-based host-guest chemistry and so on.A tetramethyl substituted cucurbit[8]uril?TMeQ[8]?was synthesized by using common glycoluril dimer and methylglycolide diether as raw materials.TMeQ[8]has good water solubility,therefore,it can exhibit characteristics different from Q[8],for example,by forming a host-guest inclusion complex to improve the solubility of insoluble compounds.