14-高分子科学导论-Supramolecular polymers

Supramolecularpolymers四川大学化学学院超分子聚合物IntroductiontopolymerscienceBasicoftheSupramolecularSupramolecularpolymerAsupramolecularpolymerisapolymerwhosemonomerrepeatunitsareheldtogetherbynoncovalentbonds.Non-covalentforcesthatholdsupramolecularpolymerstogetherincludecoordination,π-πinteractions,andhydrogenbonding.OPOOHOOH2CNONNHNNHHOPOHOOOCH2NNNOOPOHOOOCH2HHOPOOHOOH2CNNNNNNNOCH3OHH腺嘌呤胸腺嘧啶鸟嘌呤胞嘧啶HSupramolecularpolymerJean-MarieLehnColloidEarly20thcenturyLinearpolymerfrom1930Supramolecularpolymerfrom1997DonaldJ.CramCharlesJ.PedersenDefinitionofSupramolecularpolymerPolymericarraysofmonomericunitsthatarebroughttogetherbyreversibleandhighlydirectionalsecondaryinteractions,resultinginpolymericpropertiesindiluteandconcentratedsolutions,aswellasinthebulk.molecularchemistryatom+atom→molecular（covalent）supramolecularchemistrymolecular+molecular→supramolecular（noncovalent）IntermolecularInteractions“SupramolecularChemistryisthechemistryoftheintermolecularbond,concerningthestructureandfunctionsoftheentitiesformedbytheassociationoftwoormorechemicalspecies.”(byJean-MarieLehn)CovalentbondC-Obond340kJ/molC-Cbond360kJ/molC-Hbond430kJ/molC=Cbond600kJ/molC=Obond690kJ/molDrivingForcefortheFormationofSupramolecularStructuresHydrophobicinteraction40kJ/molElectrostaticinteraction-20kJ/molHydrogenbondinteraction12~30kJ/molVanderWaalsinteraction0.4-4kJ/molCation-πinteraction5-80kJ/molπ-πinteraction0-50kJ/molCoordinationinteraction(Host-guestinteraction)vanderWaalsInteraction:StickySecretsoftheGeckoThetoesofthegeckohaveaspecialadaptationthatallowsthemtoadheretomostsurfaceswithouttheuseofliquidsorsurfacetension.theattractiveforcesthatholdgeckostosurfacesarevanderWaalsinteractionsbetweenthefinelydividedsetaeandthesurfacesthemselves.Everysquaremillimeterofagecko'sfootpadcontainsabout14,000hair-likesetae.Eachsetahasadiameterof5micrometers.HydrophobicinteractionHydrophobicmoleculestendtobenon-polarandthuspreferotherneutralmoleculesandnon-polarsolvents.Hydrophobicmoleculesinwateroftenclustertogetherformingmicelles.Wateronhydrophobicsurfaceswillexhibitahighcontactangle.HydrogenbondAhydrogenbondistheattractiveinteractionofahydrogenatomwithanelectronegativeatom,likenitrogen,oxygenorfluorine.Thehydrogenmustbecovalentlybondedtoanotherelectronegativeatomtocreatethebond.Thesebondscanoccurbetweenmolecules(intermolecularly),orwithindifferentpartsofasinglemolecule(intramolecularly).TheHydrogenbondscanvaryinstrengthfromveryweak(1-2kJ/mol)toextremelystrong(155kJ/mol),Typicalvaluesinclude:F—H...:F(155kJ/molor40kcal/mol)O—H...:N(29kJ/molor6.9kcal/mol)O—H...:O(21kJ/molor5.0kcal/mol)N—H...:N(13kJ/molor3.1kcal/mol)N—H...:O(8kJ/molor1.9kcal/mol)π-πstackingπ-πstackingarecausedbyintermolecularoverlappingofp-orbitalsinπ-conjugatedsystems,sotheybecomestrongerasthenumberofπ-electronsincreases.π-πstackinginteractionsactstronglyonflatpolycyclicaromatichydrocarbonssuchasanthracene,triphenylene,andcoronenebecauseofthemanydelocalizedπ-electrons.π-πstacking(aromaticinteraction).Weakelectrostaticinteractionbetweenaromaticrings.Therearetwogeneraltypes:face-to-faceandedge-to-face:Face-to-faceπ-stackinginteractionsareresponsiblefortheslipperyfeelofgraphite.Similarπ-stackinginteractionshelpstabilizeDNAdoublehelix.Face-to-faceedge-to-faceSelf-assemblySelf-assemblyisatermusedtodescribeprocessesinwhichadisorderedsystemofpre-existingcomponentsformsanorganizedstructureorpatternasaconsequenceofspecific,localinteractionsamongthecomponentsthemselves,withoutexternaldirection.Thatiswithoutguidanceormanagementfromanoutsidesource(otherthantoprovideasuitableenvironment).moleculecomponentssupramoleculardevicecomponentsSelf-assemblySelf-assemblycanbeclassifiedaseitherstaticordynamic.Instaticself-assembly,theorderedstateformsasasystemapproachesequilibrium,reducingitsfreeenergy.Howeverindynamicself-assembly,patternsofpre-existingcomponentsorganizedbyspecificlocalinteractionsarenotcommonlydescribedasself-assembledbutself-organized.UnitoftheSupramolecularUnitofSupramolecularBasedonhydrogen-bondingBasedonπ-πstackingBasedoncoordination(Host-guest)BasedonmiscellaneousinteractionsBasedonhydrogen-bondingLiquidCrystallinesupramoleculardevelopedbyLehn,basedontriplehydrogenbondsBasedonhydrogen-bondingBasedonhydrogen-bondingDiblockcopolymerTautomerizationHomodimerizationHeterodimerizationUPy-UPyUPy-Napy1,8-naphthyridineUreidopyrimidinonesBasedonπ-πstackingtriphenylenesR=C5H11,C9H19,C11H23,C6H13R=C3H7CH(CH3)C3H6CH(CH3)2R=(C2H4O)2CH3ROROORORROORBasedoncoordinationNNRNNRRRNNRNNRRRNNRNNArNNRRRNNRCuCuCu+[Cu(CH3CN)4]+PF6-MetalIonPF6-PF6-PF6-BasedonmiscellaneousinteractionsCharacteristicsoftheSupramolecularsFacileandeconomicsynthesisSelf-assemblyinvolvestheaggregationofmoleculesandmacromoleculestothermodynamicallystablestructureswhichareheldtogetherbyweaknoncovalentinteractions.ReversibilityandSelf-repairingReversibleaggregatesthatcanbreakandrecombineonexperimentaltimescalesEnvironmentalresponsiveThenoncovalentinteractionsaresensitivetoenvironmentchange,suchassolvent,temper