Developments in the synthesis of zwitterionic olefin polymerization catalysts

222 Pages·1997·8 MB·English

by  Miller, H. Jerrold

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