Developments in the synthesis of zwitterionic olefin polymerization catalysts PDF
Preview Developments in the synthesis of zwitterionic olefin polymerization catalysts
DEVELOPMENTSINTHESYNTHESISOF ZWITTERIONICOLEFINPOLYMERIZATIONCATALYSTS By H.JERROLDMILLER ADISSERTATIONPRESENTEDTOTHEGRADUATESCHOOL OFTHEUNIVERSITYOFFLORIDAINPARTIALFULHLLMENT OFTHEREQUIREMENTSFORTHEDEGREEOF DOCTOROFPHILOSOPHY UNIVERSITYOFFLORIDA 1997 ACKNOWLEDGEMENTS Firstandforemost,Ineedtothankmyparents. Becauseofthem,Iam whoIamtoday,andwithouttheirguidance,support,andlove,noneofthis wouldhavebeenpossible. Ihaven'tbeentheclosestsonsinceImovedaway, firsttocollegeandthentogradschool,butjustknowingthattheylovedme andwerethereifIneededthemwascomforting. Ialsowanttothankmy sister,Kathie,whohasbeenverysupportiveandagreatsister. Mytwoadvisors,DaveRichardsonandJimBoncella,wereobviously instrumentalinmyconversionfromashortordercook,followingrecip>esof others,intoafirstclasschef,makingmyownrecipesforotherstofollow. Davehasshownmetheimportanceofunderstandingfundamentalconcepts, andhasbeenextremelysuccessfulinfindingwaystomotivatemeinmyless productivetimes. Hisenthusiasmformychemistryhasbeenveryrefreshing andoftenhashelpedmepushthatextrayardtogettheresults. Inthelast fiveyears,hehasbecomeagoodfriend,aswellasamentor. Jimhasshown metheimportanceofkeepingtrackoftheliterature. Hehasworkedhardto breakmeofmyhabitofreinventingthewheel. Mostimportantly,Jimtaught meeverythingIknowaboutworkingwithair-andmoisture-sensitive chemicals,withoutwhichnoneofthisdissertationwouldhavebeen successful. Hehasgivenmetheskillsthatwillallowmetobesuccessfulfor therestofmycareer,forwhichIameternallygrateful. 11 TheauthorwishestoacknowledgeDr.KhalilAbboud,notonlyfor solvingandhelpinginterpretallofthecrystalstructures,butalsoforbeing verypatientwiththeauthoroverthelastfouryears. Allmembers,bothpastandpresent,oftheRichardsonandBoncella groupsalsoneedtoberecognized. TheyincludePerlaIzsak,SteveWang, RyanMills,JonPenney,CarlosOrtiz,DanVandelende,WillVaughn,Larry Villaneueva,LauraBlosch,CelesteRegino,KenWeakly,DerikaRivers, MaureenBurkhart,Tu-caiZheng,FaisalShafiq,andGeorgeAlameddin. I especiallyneedtothankPercyDoufou,JoyMendez,MattRyan,andDave Knoeppelforbeinggreatfriendsaswellascoworkers. Unfortunately,thereis notroomortimeformetoexplainhowinstrumentalallofthesepeople havebeeninmydevelopmentwiththeirsupport,advice,criticism,humor, andfriendship,sojustletmesayTHANKS. Twospecialfriendsrequirespecialrecognition. TomHayeshasbeena bestfriendforthelasteightyears,andmakingthetripfromOhiotoHorida wasespeciallyeasyknowingsuchagoodfriendwasgoingwithme. DominickValentibecameagreatfriendinthelastfouryears,andmany questionsaboutbothchemistryandwomenweresolvedbythetwoofusover drinksatthePorpoiseandelsewhere. Ofcourse,IneedtoacknowledgeSheeba,Harry,andJennyfortheir never-endingloveandloyalty. Icouldalmostfeelmyblood-pressure droppingasIgotatherapeuticcuddlefromanyofthethreeofthem. Finally,andmostimportantly,Ineedtothankmynewwife.Heather. Shehasmadethelastfouryearsofmylifewonderful,andIlookforwardto spendingtherestofourlivestogether. Therehavebeenmanytimeswhen thingsseemedterrible,andIfeltlikeitwouldnevergetbetter,butherlove andsupporthashelp>edmep>ersevere,andIwillloveherforever. Ill TABLEOFCONTENTS ACKNOWLEDGEMENTS ii ABSTRACT vii CHAPTERS 1 INTRODUCTION 1 HistoryofHeterogeneousSystems 1 HistoryofHomogeneousSystems 4 2 APPLICATIONOFHYDROBORATIONTOTHESYNTHESIS OFZWITTERIONIC,GROUP4SINGLE-SITE POLYMERIZATIONCATALYSTS 23 Introduction 23 ExperimentalSection 24 GeneralConsiderations 24 Procedures 25 ResultsandDiscussion 28 Syntheses 28 HydroborationReactions 30 Conclusions 38 3 SYNTHESIS,CHARACTERIZATION,ANDSTRUCTUREOF NOVELBORANE-ANDBORATE-CONTAINING RUTHENOCENES 40 Introduction 40 ExperimentalSection 42 GeneralConsiderations 42 Procedures 43 X-RayStructuralAnalysisof3-3 45 X-RayStructuralAnalysisof3-6b 46 ResultsandDiscussion 47 Syntheses 47 NMRStudies 51 X-RayStructuralAnalyses 64 iv OxidationReactionsWith3-6 Conclusions ^ 4 SYNTHESIS,CHARACTERIZATION,ANDSTRUCTUREOF GROUP4METALLOCENESCONTAININGTHE FUNCnONALIZABLEP-HALOPHENYL(DIMETHYL)METHYL- CYCLOPENTADIENYLLIGAND 67 Introduction ExperimentalSection 69 GeneralConsiderations 69 Procedures X-RayStructuralAnalysisof4-1and4-3 72 ResultsandDiscussion S)mtheses X-RayStructuralAnalyses 75 ReactionsofZirconocenes Conclusions 5 THEAPPLICATIONOFTIN-COUPLINGMETHODSTOTHE SYNTHESISOFZWITTERIONICGROUP4METALLOCENES 85 Introduction 85 ExperimentalSection 87 GeneralConsiderations 87 Procedures 88 ResultsandDiscussion Future Work 6 SYNTHESIS,CHARACTERIZAHON,ANDREACTIVITYOF NOVELBORATE-CONTAININGBRIDGING CYCLOPENTADIENYL-SILYL-AMIDOCOMPLEXES 99 Introduction ExperimentalSection GeneralConsiderations 101 Procedures ResultsandDiscussion 116 7 SYNTHESISOFDIIMINELIGANDSANDLIGAND PRECURSORSFORTHEDEVELOPMENTOFZWITTERIONIC, LATETRANSITIONMETALDHMINECATALYSTS 144 Introduction ExperimentalSection I45 GeneralConsiderations I45 Procedures 245 ResultsandDiscussion 8 SUMMARY 250 APPENDDC LISTOFREFERENCES 203 BIOGRAPHICALSKETCH 919 vi AbstractofDissertationPresentedtotheGraduateSchool oftheUniversityofHoridainPartialFulfillmentofthe RequirementsfortheDegreeofDoctorofPhilosophy DEVELOPMENTSINTHESYNTHESISOFZWITTERIONIC OLEFINPOLYMERIZATIONCATALYSTS By H.JerroldMiller August,1997 Chairmen: DavidRichardson/JamesBoncella MajorDepartment: Chemistry Potentialmethodsforthesynthesisofzwitterionic,single-site polymerizationcatalystswereexamined,andanumberofcomplexeswere prepared. Thepreparedcomplexesareearlytransitionmetalmetallocenes, whicharenotzwitterionicspecies,andansfl-silyl-bridgedcyclopentadienyl- amido(Cp-amido)complexes,someofwhicharezwitterionicspecies. Inthe processofpreparingthesecomplexes,modelruthenocenecomplexeswere preparedemployingthesameligands,andtheirreactivitywasalsoexamined. AseriesofmetallocenecomplexeswerepreparedbyusingCpligands derivedfrom6,6-dimethylfulvene. Theadditionoflithium diisopropylamide(LDA)to6,6-dimethylfulveneleadstodeprotonationofthe p-exocarbonandthesynthesisoftheanionicmethylvinyl-Cp,CpCsHs, ligand. Thisligandwasusedtoprepareaseriesofmetallocenes,andthe vii reactivityofthesecomplexestowardhydroborationwithPh2BH»Pywas examined.Theruthenocenereactedwiththeboraneyieldingreductionofthe doublebond. However,withzirconocenes,reactivitywasobservedbetween theboraneandthemetalcenter. Withthedimethylzirconocene,thisledtoa newcomplexwhosestructureisproposedbasedonspectroscopicdata. AnewCpligand,alsobasedon6,6-dimethylfulvene,waspreparedby theadditionof(p-bromo-or(p-iodophenyl)lithium to6,6-dimethylfulvene. ThisyieldedtheanionicCpligandCpC(CH3)2C6H4X(X=Br,I)fromwhichwas preparedanumberofmetallocenes. Whenan18electronruthenocene complexwaspreparedwiththeligand,halo-lithiumexchangeoccurredatthe ligand,andtrappingtheresultinglithiatewithboranesyieldedaborate- containingruthenocene,andaborane-containingruthenocene. Similar chemistrywasattemptedwith16electronzirconiumcomplexes,however reactivityoccurredatthemetalcenter. Sinceitwasnotpossibletoprepareborate-containingmetalcomplexes aftertheligandwascoordinatedtoearlytransitionmetals,methodsfor preparingtheborate-containingligandpriortocoordinationwereexamined. Preliminarystudiesusingtin-couplingmethodsappearpromisingforthe synthesisofborate-containingmetallocenes,andmoreworkisrequiredto fullyunderstandthesesystems. Theuseofsilyl-bridgedcyclopentadienyl- amidoligandshasproventobeaverysuccessfulmethodforthes)mthesisof borate-containingligands,andmetalcomplexescontainingtheseligands havebeenprepared. Intheprocess,aseriesofborate-containinganiline derivativeshavebeenprepared,whichappeartohaveagreatdealof potentialasligandsintransitionmetalchemistry. viii CHAPTER1 INTRODUCTION HistoryofHeterogeneousSystems. Whilestudyingtheformationoflong-chaintrialkylaluminum compoundsviatheinsertionofethyleneintoAl-Cbonds,KarlZieglerand coworkersmadeaserendipitousdiscovery. Whentraceamountsofanickel compoimdwereleftfromaprevioushydrogenationreactioninthe autoclave,theonlyproductobservedwas1-butene. Thisbecameknownas the"nickeleffect,"andledZieglertoexaminetheeffectofotherheavymetals ontheinsertionreaction. Then,inlate1953,Zieglerandcoworkers^found thatthepresenceofzirconiumacetylacetonateduringthereactionled exclusivelytohighmolecularweightpolyethylene(HMWPE)atambient temperaturesandpressures. Thisdiscoverywasastonishingconsidering polyethylene(PE)waspreviouslyonlypreparedbyaradicalmechanism underextremelyharshconditionsofhightemp>eratureandpressure. Zieglerandcoworkers2soonestablishedthatthebestcatalystsystems forthepolymerizationofethylenetohighdensitypolyethylene(HOPE) consistedofagroup4metalchloride(Zr(m),Zr(IV),Ti(m),orTi(IV))anda trialkylalumimuncocatalyst,withthebestcatalystsystembeinga combinationofTiCUandtriethylaluminum. However,atthistime,the activesitehadnotyetbeendetermined,andargumentswerepresentedabout 1 2 whetherthealuminumspeciesorthetransitionmetalspedesservedasthe activesite. ThefirstmajorcontributortothisnewchemistrywasNattaand coworkers^,whodiscoveredthatbyusingZiegler’scatalystsystem,highera- olefins(namelypropylene)couldbepolymerizedwithhighstereospecifidty. AlthoughthereissomespeculationabouthowNattalearnedoftheMiilheim process(asthislowtemperatureandpressurepolymerizationreactionwas calledbyZiegler),thereislittledoubtabouttheimmensecontributiontothis chemistrybyNatta'sgroup. Theyquicklyandeffidentlydevisedmethodsfor determiningthestructureofstereoregularpolymerswhicharestillused today. atacticpolypropylene syndiotacticpolypropylene isotacticpolypropylene Figure1-1. Thestereospedficstructureofthethreemaintypesofpolypropylene
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