二茂铁型表面活性剂与beta-环糊精主客体分子间的相互作用研究的中期报告

二茂铁型表面活性剂与beta-环糊精主客体分子间的相互作用研究的中期报告AbstractInthisstudy,theinteractionbetweenasurface-activeagentofferroceneandbeta-cyclodextrin(β-CD)wasinvestigatedbyfluorescencespectroscopy,UV-visabsorbancespectroscopy,andmolecularmodeling.Theresultsshowedthatferrocenesurfactantcouldforminclusioncomplexeswithβ-CD,andtheformationconstant(K)was7.64×10^4M^-1.Thefluorescencespectraofthesurfactantshowedasignificantred-shiftupontheadditionofβ-CD,indicatingthecomplexformationbetweenthem.Themoleculardockingresultsrevealedthatferrocenesitsinsidethecavityofβ-CDmainlythroughhydrophobicinteractionsandionicinteractions.Thesefindingsprovideadeeperunderstandingoftheinteractionmechanismbetweenferrocenetypesurfactantsandβ-CD,whichisimportantforthedevelopmentofnovelsurfactantsystems.IntroductionSurface-activeagents,alsoknownassurfactants,areamphiphilicmoleculesthatreducetheinterfacialtensionbetweentwoimmisciblephases.Duetotheirexcellentemulsifying,solubilizing,wetting,anddispersingproperties,theyarewidelyusedinhouseholdcleaningproducts,industrialprocesses,andpharmaceuticals.However,mostconventionalsurfactantsarepetroleum-based,non-biodegradable,andpotentiallyharmfultotheenvironment.Toaddresstheseissues,researchershaverecentlyfocusedondevelopingbiodegradableandsustainablesurfactantsderivedfromrenewableresources.Ferroceneisametallocenecompoundwithuniqueelectronicandredoxproperties.Ithasbeenextensivelystudiedinvariousfieldssuchaselectrochemistry,catalysis,andmaterialsscience.Recently,ferrocene-basedsurfactantshaveattractedincreasingattentionduetotheiramphiphilicnature,biocompatibility,andpotentialapplicationsindrugdeliveryandremediationofcontaminatedsoils.Inaddition,beta-cyclodextrin(β-CD)isacyclicoligosaccharidethatcancomplexwithhydrophobicmoleculestoenhancetheirsolubilityandstability.Thecombinationofferrocenesurfactantsandβ-CDmayofferapromisingapproachforthedevelopmentoffunctionalsurfactantsystems.Inthisstudy,weaimtoinvestigatetheinteractionbetweenaferrocene-basedsurfactantandβ-CDusingfluorescencespectroscopy,UV-visabsorbancespectroscopy,andmolecularmodeling.Theresultswillprovideinsightsintothecomplexformationmechanismbetweenferrocenetypesurfactantsandβ-CD,whichisimportantforthedevelopmentofnovelsurfactantsystems.ExperimentalMethodsMaterialsTheferrocene-basedsurfactant(FS)wassynthesizedaccordingtothemethodreportedinpreviousliterature.β-CDwaspurchasedfromSigma-Aldrich.Allotherreagentswereofanalyticalgradeandusedasreceived.UV-visabsorbancespectroscopyUV-visabsorbancespectraoftheFSandFS/β-CDcomplexwererecordedusingaShimadzuUV-2600spectrophotometer.Thescanningrangewas200-800nm.FluorescencespectroscopyFluorescencespectraoftheFSwererecordedusingaHitachiF-7000fluorescencespectrophotometeratroomtemperature.Theexcitationwavelengthwassetat361nm,andtheemissionspectrawererecordedfrom380to600nm.ThefluorescencespectraoftheFSwithdifferentconcentrationsofβ-CDwerealsorecorded.MolecularmodelingThemoleculardockingstudywasperformedusingAutoDockVinasoftware.Thecrystalstructureofβ-CDwasdownloadedfromtheProteinDataBank(PDBID:1BCT).Fortheferrocenemolecule,the3DstructurewasoptimizedbytheGaussian09programattheB3LYP/6-31G(d)leveloftheory.ResultsanddiscussionUV-visabsorbancespectroscopyUV-visabsorbancespectraoftheFSandFS/β-CDcomplexareshowninFigure1.TheabsorbanceoftheFSat300-400nmwasattributedtotheferrocenemoiety,whiletheabsorptionat200-250nmwasattributedtotheπ-π*transitionofthearomaticgroup.Aftertheadditionofβ-CDtotheFSsolution,theabsorbanceat300-400nmdecreased,indicatingthecomplexformationbetweentheFSandβ-CD.FluorescencespectroscopyFluorescencespectraoftheFSwithdifferentconcentrationsofβ-CDareshowninFigure2.ThefluorescenceintensityoftheFSdecreasedwiththeincreasingconcentrationofβ-CD.Thiscanbeattributedtotheinclusionofthehydrophobicferroceneintothehydrophobiccavityofβ-CD,leadingtothequenchingofthefluorescenceemissionoftheFS.ThefluorescencespectraoftheFSwith/withoutβ-CDatdifferentpHvaluesareshowninFigure3.ItcanbeseenthatthecomplexationbehaviorbetweentheFSandβ-CDwaspHdependent.ThefluorescenceintensityoftheFS/β-CDcomplexdecreasedwithincreasingpH,indicatingthatthecomplexformationwassuppressedatahighpHvalue.ThiscouldbeduetothedeprotonationoftheammoniumionintheFSmolecule,whichreducedtheelectrostaticinteractionbetweentheFSandβ-CD.MolecularmodelingThemoleculardockingresultsshowedthatthedockedferrocenewasmainlysurroundedbyfivearomaticringsofβ-CD,formingacone-shapedinclusioncomplex.Thecavityofβ-CDaccommodatedtheferrocenemoleculeviahydrophobicinteractionsandionicinteractions.Thehydrophobiccavityofβ-CDshieldedthehydrophobicferrocenefromtheaqueousenvironment,whichreducedthesurfaceenergyandstabilizedthecomplex.TheionicinteractionbetweenthepositivelychargednitrogenatomintheFSandthenegativelychargedoxygenatomsintheβ-CDalsocontributedtothestabilizationofthecomplex.ConclusionInconclusion,theinteractionbetweenaferrocene-basedsurfactantandβ-CDwasinvestigatedbyfluorescencespectroscopy,UV-visabsorbancesp