Quantitative Research. Cup Aromatics Conformation And Quantum Chemical Study On Conversion Mechanism Of Oxygen Molecules Cluster Molecular Configuration

AbstractCalixarenes are macrocyclic compounds essentially made of thephenolic residues linked by methylene grouPs (-CH2-),and they havecone-shaPed cavityIn recent 20 years, Calixarenes chendstry hasbeen developed raPidly. Calixarenes have attf8cted much interestbecause of their unique charactersfCalixarenes have cyclic phenoIichydroxyl grouPs which are useful for the building-up of thefimctionalized host m o lecul e s. F urthe more, C al ixarene s have several-sised n-rich cavity for including gUest compounds.Calixarene hasthe advamage of compIexation with both ionic and nelltr3l gUestscompared with Cyclodextrin and Crown etherComputationaI studiesof congormational isomerism in calixarenes have been of much.concern recently.Among them,calix<4>arene are of sPecialinterest.Calix<4>arene derivatives actUally consist of a l6-membered ring but involve only four stable and significantconfOrmerst cone, partial cone, l,2-alter, l,3-alter.In this paPer,we use the semi-emPtrical molecular orbitalmethodstom3),to study the four conformations of calix<4>arene.We conclude that the order of the relative stability for these fourconformations is:Cone>l,3-alter>partial cone>l,2-alterWe think the order of energy is determined by both hydrogenbonding and extensity of conformation.Ih this paPer we aIso study the pathways for conformational3interconversion of calix<4>arenes.There are many suPpose of thepathways of conformational interconversion,and they are llotuniformed. We calculate the energy barrier of every possibIeinterconversion pathway by semi-empirica1 molecular orbitalmethod .We get the most possible pathway by the different method,the result is i,theW ndnd l,We= ghare~ ~nd l,We= ghareIt's coincide with the result of exPeriment. So the pathWay ispIausible.