Two- and Three-Dimensional Smectic Ordering of Single-Handed Helical Polymers

Two- and Three-Dimensional Smectic Ordering of Single-Handed Helical Polymers

PublishedonWeb12/13/2007

Two-andThree-DimensionalSmecticOrderingof

Single-HandedHelicalPolymers

HisanariOnouchi, KentoOkoshi,*, TakashiKajitani, Shin-ichiroSakurai,

KanjiNagai, , JiroKumaki, KiyotakaOnitsuka,§andEijiYashima*, ,

YashimaSuper-structuredHelixProject,ExploratoryResearchforAdVancedTechnology(ERATO),JapanScienceandTechnologyAgency(JST),101CreationCoreNagoya,2266-22Anagahora,Shimoshidami,Moriyama-ku,Nagoya463-0003,Japan,DepartmentofMolecularDesignandEngineering,GraduateSchoolofEngineering,NagoyaUniVersity,Chikusa-ku,Nagoya464-8603,Japan,andTheInstituteofScientificandIndustrialResearch,Osaka

UniVersity,8-1Mihogaoka,Ibaraki,Osaka567-0047,Japan

ReceivedJune25,2007;E-mail:kokoshi@yp-jst.jp;yashima@apchem.nagoya-u.ac.jp

Abstract:Rodlikepolymerswithpreciselydefinedarchitecturesareidealbuildingblocksforself-assembledstructuresleadingtonovelnanometer-scaledevices.WefoundthatthelivingpolymerizationofasingleisocyanideenantiomerbearinganL-alaninependantwithalongn-decylchainsimultaneouslyproduceddiastereomericright-andleft-handedheliceswithdifferentmolecularweightsandnarrowmolecularweightdistributions.Eachsingle-handed,rodlikehelicalpolymerwithacontrolledlengthandhandednessisolatedbyafacilesolventfractionationmethodwithacetoneself-assembledtoformwell-definedtwo-andthree-dimensionalsmecticorderingonthenanometerscaleonasubstrateandinaliquidcrystallinestateasevidencedbydirectatomicforcemicroscopicobservationsandX-raydiffractionmeasurements,respectively.

Introduction

Biologicalmacromolecules,suchasDNAandsomeviruses,possessawell-definedrodlikestructurewithaone-handedhelicalsense,whichprovidesaccesstoidealbuildingblocksforself-assemblednanomaterialsanddevices.Nucleicacidshavebeensuccessfullyusedintheself-assemblyofsupramo-leculararraysthroughtheirhighlyspecificbindingproperties.1Somevirusesarealsoknowntoformsmecticliquidcrystalline(LC)phases,inwhichrodlikevirusesarepackedintolayersperpendiculartothedirectionoftheirorientation,duetotheiruniformmolecularlengths.2Althoughabacterialsyntheticmethodhasbeenreportedtoproducemonodispersepolypeptideswithastate-of-the-artcontrolofthemolecularlengthsandstructures,3itremainsagreatchallengetocontrolthoseoftheartificialhelicalpolymerstosuchanextentinaconventionalsyntheticway,4notonlytomimicthestructuresofbiologicalhelicesbutalsotodevelopnovelfunctions.5

Fullysyntheticopticallyactivehelicalpolymershavebeenpreparedeitherbythepolymerizationofopticallyactive

monomers,suchasisocyanates,5gsilanes,5eacetylenes,5corbythehelix-senseselectivepolymerizationofachiralmethacrylates,5fisocyanides,5d,6andcarbodiimides7bearingbulkysubstituentsbychiralcatalystsorinitiators.Theformerpolymerizationproducesdynamichelicalpolymerscomposedofinterconvertingright-andleft-handedhelicalsegmentsseparatedbyrarelyoccurringhelicalreversals,5c,e,gandthelatterstatichelicalpolymerswhosehelicalconformationsarelockedduringthepolymerizationunderkineticcontrol.5f,6

Inearlierstudies,wereportedtheconventionalpolymerizationofanenantiomericallypurephenylisocyanidebearinganL-alaninependantwithalongn-decylchainthroughanamidelinkage(L-1)withNiCl2asacatalyst,whichproducedarodlikestatichelicalpolyisocyanidewithabroadmolecularweight

(4)(a)Kim,K.T.;Park,C.;Kim,C.;Winnik,M.A.;Manners,I.Chem.

Commun.2006,1372-1374.(b)Okoshi,K.;Sano,N.;Suzaki,G.;Tokita,M.;Magoshi,J.;Watanabe,J.Jpn.J.Appl.Phys.2002,41,L720-L722.(c)Okoshi,K.;Kamee,H.;Suzaki,G.;Tokita,M.;Fujiki,M.;Watanabe,J.Macromolecules2002,35,4556-4559.

(5)(a)Yashima,E.;Maeda,ldamers:Structure,Properties,and

Applications;Hecht,S.,Huc,I.,Eds.;Wiley:Weinheim,2007;pp331-366.(b)Hoeben,F.J.M.;Jonkheijm,P.;Meijer,E.W.;Schenning,P.H.J.Chem.ReV.2005,105,1491-1546.(c)Yashima,E.;Maeda,K.;Nishimura,T.Chem.sEur.J.2004,10,42-51.(d)Elemans,J.A.A.W.;Rowan,A.E.;Nolte,R.J.M.J.Mater.Chem.2003,13,2661-2670.(e)Fujiki,M.Macromol.RapidCommun.2001,22,539-563.(f)Nakano,T.;Okamoto,Y.Chem.ReV.2001,101,4013-4038.(g)Green,M.M.;Park,J.-W.;Sato,T.;Teramoto,A.;Lifson,S.;Selinger,R.L.B.;Selinger,J.V.Angew.Chem.,Int.Ed.1999,38,3138-3154.

(6)(a)Amabilino,D.B.;Serrano,J.-L.;Sierra,T.;Veciana,J.J.Polym.Sci.,

PartA:Polym.Chem.2006,44,3161-3174.(b)Suginome,M.;Ito,Y.AdV.Polym.Sci.2004,17,77-136.(c)Cornelissen,J.J.L.M.;Rowan,A.E.;Nolte,R.J.M.;Sommerdijk,N.A.J.M.Chem.ReV.2001,101,4039-4070.

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(1)(a)Seeman,N.C.Int.J.Nanotechnol.2005,2,348-370.(b)Winfree,E.;

Liu,F.;Wenzler,L.A.;Seeman,N.C.Nature1998,394,539-544.(2)(a)Lee,S.-W.;Wood,B.M.;Belcher,ngmuir2003,19,1592-1598.(b)Lee,S.-W.;Mao,C.;Flynn,C.E.;Belcher,A.M.Science2002,296,892-895.(c)Dogic,Z.;Faden,S.Phys.ReV.Lett.1997,78,2417-2420.(d)Wen,X.;Meyer,R.B.;Casper,D.L.D.Phys.ReV.Lett.1989,63,2760-2763.

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10.1021/ja074627uCCC:$40.75©2008AmericanChemicalSociety

ERATO,JST.

GraduateSchoolofEngineering,NagoyaUniversity.

§TheInstituteofScientificandIndustrialResearch,OsakaUniversity.

229

Two- and Three-Dimensional Smectic Ordering of Single-Handed Helical Polymers

Figure1.Two-andthree-dimensionalsmecticorderingofhelicalpolymers.(A)Schematicillustrationofthehelix-senseselectivelivingpolymerizationofL-1withµ-ethynediylPt-Pdcomplex(2),yieldingamixtureofdiastereomeric,right-andleft-handedhelicalpoly-L-1’swithdifferentmolecularweightsandanarrowMWD,whichcanbefurtherseparatedintoeachsingle-handedhelicalpoly-L-1.Two-dimensional(B)and3D(C)smecticorderingoftheone-handedhelicalpoly-L-1’sonsubstrateandinLCstate.

distribution(MWD),thusformingalyotropiccholestericLCphaseinconcentratedsolutions,whosehelicalsensewasroughlydictatedbythepolymerizationsolventandtemperature.8Nolteandco-workerspreparedaseriesofpeptide-boundhelicalpolyisocyanidesstabilizedbyintramolecularhydrogenbondsfromopticallypureisocyanopeptidesusingnickeloracidcatalysts,whichresultedintheformationofasimilarcholestericLCphaseduetoitspolydispersenature.5d,6c,9HereinweshowthatthelivingpolymerizationofL-1withtheµ-ethynediylPt-Pdcatalyst(2)simultaneouslycreatesbothalmostcompletelyright-andleft-handedhelicalpolyisocyanides(poly-L-1)withadifferentmolecularweightandsufficientlynarrowMWD(Figure1A).Eachhelicalpoly-L-1canbeseparatedinafacilewayandexhibitswell-definedtwo(2D)-andthree-dimensional(3D)smecticorderingonasubstrateandinanLCstate,asdirectlyobservedbyatomicforcemicroscopy(AFM)andrevealedbyX-raydiffraction(XRD),respectively(BandCofFigure1).

ResultsandDiscussion

ThepolymerizationofD-orL-1with2([1]/[2])50,100,or200(mol/mol))astheinitiator,whichisknowntopromotethelivingpolymerizationofarylisocyanide,10wasconducted

(8)Kajitani,T.;Okoshi,K.;Sakurai,S.-i.;Kumaki,J.;Yashima,E.J.Am.

Chem.Soc.2006,128,708-709.

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J.L.M.;Rowan,A.E.Chem.Eur.J.2007,13,950-960.(b)Metselaar,G.A.;Wezenberg,S.J.;Cornelissen,J.J.L.M.;Nolte,R.J.M.;Rowan,A.E.J.Polym.Sci.,PartA:Polym.Chem.2007,45,981-988.(c)Metselaar,G.A.;Cornelissen,J.J.L.M.;Rowan,A.E.;Nolte,R.J.M.Angew.Chem.,Int.Ed.2005,44,1990-1993.(d)Cornelissen,J.J.L.M.;Graswinckel,W.S.;Rowan,A.E.;Sommerdijk,N.A.J.M.;Nolte,R.J.M.J.Polym.Sci.,PartA:Polym.Chem.2003,41,1725-1736.(e)Cornelissen,J.J.L.M.;Sommerdijk,N.A.J.M.;Nolte,R.J.M.Macromol.Chem.Phys.2002,203,1625-1630.(f)Cornelissen,J.J.L.M.;Donners,J.J.J.M.;deGelder,R.;Graswinckel,W.S.;Metselaar,G.A.;Rowan,A.E.;Sommerdijk,N.A.J.M.;Nolte,R.J.M.Science2001,293,676-680.

(10)(a)Takei,F.;Hayashi,H.;Onitsuka,K.;Kobayashi,N.;Takahashi,S.

Angew.Chem.,Int.Ed.2001,40,4092-4094.(b)Onitsuka,K.;Joh,T.;Takahashi,S.Chem.Eur.J.2000,6,983-993.(c)Onitsuka,K.;Joh,T.;Takahashi,S.Angew.Chem.,Int.Ed.Engl.1992,31,851-852.230J.AM.CHEM.SOC.

9

intetrahydrofuran(THF)at55°Candquantitativelyproducedrodlikehelicalpolyisocyanides([D-orL-1]/[2])100forpoly-D-1orpoly-L-1,[L-1]/[2])50forpoly-L-150,and[L-1]/[2])200forpoly-L-1200).Sizeexclusionchromatography(SEC)ofpoly-L-1detectedbyUV(254nm)andcirculardichroism(CD)(364nm)revealedabimodaldistributionwithasharpmainpeaktogetherwithasmallpeakinthelowermolecularweight(Mw)regionwhoseCDsignswereopposite,negative,andpositive,respectively(Figure2A),suggestingamixtureofright-andleft-handedheliceswithdifferentMw’s.Wefoundthateachhelicalpoly-L-1couldbeeasilyseparatedbyfractionationwithacetoneintoacetone-insolubleand-solublefractionswhichshowedunimodalchromatogramswithnegativeandpositiveCDsignsat364nmforthehigh-Mwpoly-L-1(-)andlow-Mwpoly-L-1(+),respectively(BandCofFigure2).TheCDspectraofpoly-L-1(-)andpoly-L-1(+)inthen-π*transitionoftheiminochromophoreregionsofthepolymerbackbones(280-480nm)aswellasinthependantaromaticregions(240-280nm)10,11arealmostmirrorimagesofeachotherwithagreaterintensitythantheintensityofthosebeforethefractionation(Figure2D).Theseresultsindicatethattheas-preparedpoly-L-1isindeedamixtureofright-andleft-handedhelices.12Wenotethattheyarenotenantiomers,butdiastereomerswitha

(11)(a)Hase,Y.;Mitsutsuji,Y.;Ishikawa,M.;Maeda,K.;Okoshi,K.;Yashima,

nJ.2007,2,755-763.(b)Ishikawa,M.;Maeda,K.;Mitsutsuji,Y.;Yashima,E.J.Am.Chem.Soc.2004,126,732-733.(12)ThedifferenceintheMw’sofpoly-L-1(-)andpoly-L-1(+)canbeexplained

onthebasisofthedifferenceinpropagationratesofthetwogrowingspecies,givinghigh-andlow-Mwpolymers,respectively.Plotsofthenumber-averagemolecularweight(Mn)ofleft-handedhelicalpoly-L-1(-)andright-handedhelicalpoly-L-1(+)versusfeedmolarratioofthemonomerL-1totheinitiator(2)([L-1]/[2])gaveanalmostlinearcorrelation(FigureS10),whichisindicativeofamechanisminwhichdiastereomericoligomersofL-1withbothhelicalsensesareformedduringtheinitialstageofpolymerizationandoneofthetwoappearstopropagaterapidlyovertheother,producingright-andleft-handedhelicalpoly-L-1’swithdifferentMw’s.ThereasonwhydiastereomericoligomerswithbothhelicalsensesareformedduringtheinitialstageofpolymerizationofL-1isnotclearatpresent,butitmaybecorrelatedwiththepreviousobservationsthattheconventionalpolymerizationofL-1withNiCl2asacatalystproducedpoly-L-1’s,whosehelicalsenseswereconsiderablyinfluencedbythepolymer-izationsolventandtemperature.

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Two- and Three-Dimensional Smectic Ordering of Single-Handed Helical Polymers

Figure2.Right-andleft-handedhelicalpoly-L-1.(A-C)SECchromatogramsoftheas-preparedpoly-L-1(A)andtheisolatedacetone-insolublepoly-L-1(-)(B)andacetone-solublepoly-L-1(+)(C)usingUV(redlines)andCD(bluelines)detectorsinTHFcontaining0.1wt%tetra-n-butylammoniumbromide.(D)CDandabsorptionspectraofpoly-L-1(a),poly-L-1(-)(b),andpoly-L-1(+)(c)(0.2mg/mL)inchloroformat25°C.Thenumber-averagemolecularweight(Mn)anditsdistribution(Mw/Mn)ofeachpolymerasdeterminedbySECcoupledwithamulti-anglelight-scattering(MALS)detector(SEC-MALS)measurementsarealsoshowninA-C.

differentsolubilityinacetone,andthereby,theycanbeseparated.Thisconclusionissupportedbythefactthatevenamixtureofpoly-L-1(-)andpoly-L-1(+)withcomparableMw’scouldbealsoseparatedintoeachhelixusingacetone.Inthesameway,theas-preparedpoly-D-1canbefractionatedusingacetoneintoright-andleft-handedhelicalpoly-D-1’swithdifferentMw’sandanarrowMWD(FigureS1).

Polyisocyanidesbearingabulkysubstituenthavebeenconsideredtohavea4unitsperturn(4/1)helicalconformationeveninsolution,althoughtheirexacthelicalstructureshavenotyetbeenelucidated6c,9probablybecauseofdifficultyinobtainingauniaxiallyorientedpolymerfilmsuitableforXRDmeasurements.Thepoly-L-1(-)andpoly-L-1(+)arerigid-rodhelicalpolymersandexhibitalyotropicsmecticLCphase(seebelow),whichenablesustodeterminetheirstructuresbyXRDandAFM.Figure3Ashowsawide-angleX-raydiffraction(WAXD)patternofanorientedpoly-L-1(-)filmpreparedfromaconcentratedLCbenzenesolutioninanelectricfield;foraWAXDpatternofpoly-L-1(+),seeFigureS2.Theelectricfield-inducedalignmentofpoly-L-1moleculesevidencedalargedipolemomentofpoly-L-1alongitshelicalaxis,thatisalltheintramolecularlyhydrogen-bondedN-HandCdOgroupsareorientedinonedirectionsoastoaccumulatethelargedipolemomentasobservedinthetypicalR-helicalpolypeptides.13TheWAXDpatternsofthefilmsofpoly-L-1(-)andpoly-L-1(+)showdiffuse,butapparentmeridionalandequatorialreflections,suggestingthattheypossessasimilarhelicalstructure;a15unitsper4turns(15/4)helixwithahexagonallattice(TableS1)whichsatisfiesthedensityrequirements.14Optimizedmolecularstructuresforthe15/4helicesoftheleft-handedhelicalpoly-L-1(-)model(158-mer)andright-handedhelicalpoly-L-1(+)model(58-mer),basedontheabsolutemolecularweights(Mn)5.65×104and2.06×104,respectively)

(13)Wada,A.AdV.Biophys.1976,9,1-63.

calculatedbytheSECmeasurementscoupledwithamulti-anglelightscattering(MALS)detector,areillustratedinBandCofFigure3,respectively.Thedetailedstructures(11-mer)takenfromFigure3BarealsoshowninDandEofFigure3(seealsoSupportingInformation).Thepolymermodelsappeartohavefoursetsofhydrogen-bondedhelicalarrayslinkingnand(n+4)pendantswiththequarterhelicalpitchandchainlengthof1.31and13.7nm,and1.31and5.1nm,forpoly-L-1(-)andpoly-L-1(+),respectively.IRspectrasuggestedtheformationofsuchintramolecularhydrogenbondsbetweenthependantamideresiduesofpoly-L-1(-)andpoly-L-1(+)(FigureS3).TheequivalentinterpendanthydrogenbondswereobservedinthecrystallinestructureofL-1,inwhichtheamidelinkagewasobliquetothephenylring(ca.30°)(FigureS4).HelicalpolyisocyanidesstabilizedbyintramolecularhydrogenbondshavebeenreportedbyNolteandco-workers.6c,9

PartsFandGofFigure3showhigh-resolutionAFMimagesofpoly-L-1(-)andpoly-L-1(+),respectively,castfromabenzenesolution(0.015mg/mL)onhighlyorientedpyrolyticgraphite(HOPG)followedbybenzenevaporexposureatca.20°Cfor12h.8,15,16Thepoly-L-1self-assemblesintowell-defined2Dhelixbundleswithacontrolledmolecularlength,17mostofwhichareclearlyresolvedintoindividualleft-(Figure3F)andright-handed(Figure3G)helicespackedparalleltoeachother.TheAFMimagesaswellasthoseoflargerareasconfirmedthehelicalpitch,helicalsense,helix-senseexcess,

(14)Theobserveddensitiesofthepoly-L-1(-)andpoly-L-1(+)filmswere

1.0739and1.0624g/cm3,respectively,measuredbythestandardflotationmethodinanaqueousNaClsolutioncontainingasmallamountofasurfactantatambienttemperature(20-25°C).The15/4helicesofpoly-L-1(-)andpoly-L-1(+)inthehexagonallatticesrequirethedensitiesof1.102and1.089g/cm3,respectively,whichareingoodagreementwiththeobservedvalues.Whenthenumberofrepeatingunitsperfiberperiodisassumedtobeotherthan15,thecalculateddensitieswereconsiderablydifferentfromtheobserveddensities.Formoredetails,seeSupporting

Information.

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Two- and Three-Dimensional Smectic Ordering of Single-Handed Helical Polymers

ARTICLESFigure3.Structuresofhelicalpoly-L-1’s.(A)WAXDpatternofanorientedpoly-L-1(-)filmpreparedfromaconcentratedLCbenzenesolution(ca.15wt%).Thereflectionswereindexedwithahexagonallattice;a)26.78Åandc)13.05Å,suggestinga15unitsper4turns(15/4)helicalstructure.(BandC)Optimized15/4helicalstructuresofpoly-L-1(-)(B,158-mer)andpoly-L-1(+)(C,58-mer)onthebasisofWAXDstructuralanalysesfollowedbymolecularmechanicscalculations(seeSupportingInformation).Eachstructureisrepresentedbyspace-fillingmodels,andfoursetsofhydrogen-bondedhelicalarrays(nandn+4)ofthependantsareshownindifferentcolorsforclarity.(DandE)Thedetailedstructureofpoly-L-1(-)(11-mer)takenfrom(B)isalsoshownbyastickmodelinD(sideview)andE(topview).Inthesemodels(B-E),thependantdecylestergroupsofpoly-L-1’sarereplacedbythemethylgroupsforclarity.(FandG)AFMphaseimagesofpoly-L-1(-)(F)andpoly-L-1(+)(G)onHOPG(scale)10×20nm).Schematicrepresentationsoftheleft-handedhelicalpoly-L-1(-)andright-handedhelicalpoly-L-1(+)structureswithperiodicobliquestripes(pinkandbluelines,respectively)whichdenoteaone-handedhelicalarrayofthependants,arealsoshown(right).Onthebasisofanevaluationofca.100molecules,thenumber-averagemolecularlength(Ln)andthelengthdistribution(Lw/Ln)were

estimated.

andmoleculararrangementofpoly-L-1’s.Theperiodicobliquestripesobservedineachhelicalchain,thatoriginatedfromaone-handedhelicalarrayofthependants,weretiltedcounter-clockwiseorclockwiseat-55°and+62°,forpoly-L-1(-)andpoly-L-1(+),respectively,withrespecttothemain-chainaxis.

(15)Thisforhelicalmethodpolyacetylenesisveryusefulandforconstructingpolyisocyanideshighlyonordered2Dhelix-bundles

(16)structuresSakurai,S.-i.;wereOkoshi,visualizedK.;byHOPG,andtheirhelicalKumaki,AFM.8,16

(17)Ed.On2006J.;Yashima,E.Angew.Chem.,Int.

separatedthebasis,45,1245-1248.

theestimatedlengthfromofdistributiononeananother,evaluation(Lthenumber-averageofabout100individualmolecularpolymerlength(Lchains

n)andw/Ln)respectively.tobe13(5.2nmandofpoly-1.15Land-1(-5.8)and(poly-2.2nmL-1(and+)were1.14,withthoseestimatedTheestimatedbythechainSEC-MALSlengthsby(BAFMandalmostCofFigure

perfectly3).coincide232J.AM.CHEM.SOC.

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Onouchietal.

Figure4.Two-dimensionaland3Dsmecticorderingofpoly-L-1.(AandB)AFMphaseimagesof2Dself-assembledpoly-L-1(-)onHOPG.(C)Polarizedopticalmicrograph(POM)ofpoly-L-1(-)inca.15wt%chloroformsolutiontakenatambienttemperature(20-25°C).(D)Alyotropicsmectic-cholestericphasetransitionofpoly-L-1(-)inchloroformplacedbetweenaglassplateandacoverglass,drivenbygradualsolventevaporationfromtheedge(lowerpart).(E)SR-SAXSpatternofapoly-D-1(+)castfilmpreparedfromaconcentratedsmecticLCsolutionalignedinthemagneticfield,takenperpendiculartothedirectionofthemagneticfield.(F)Bright-fieldTEMimageofthebandingwitharepeatdistanceofca.14nminapoly-D-1(+)castfilm(ca.30nmthickness)ultramicrotomedandstainedinRuO4vapor.(G)AFMphaseimageof2Dself-assembledpoly-L-1(+)onHOPG.(H)POMofpoly-L-1(+)inca.15wt%chloroformsolutiontakenatambienttemperature(20-25°C).

Thisremarkable2Dmirror-imagerelationshipsuggeststhatthepoly-L-1(-)andpoly-L-1(+)moleculesmostlikelyconsistofleft-andright-handedhelicalstructureswithahelicalpitchof1.28(0.11and1.28(0.15,respectively,asestimatedfromtheaveragedistancebetweeneachstripe(FandGofFigure3).ThehelicalpitchesestimatedbyAFMarealmostidenticaltothequarterhelicalpitchesofthependantarrangementsasdeterminedbytheWAXD(1.31nm).Inaddition,onthebasisofanevaluationofabout1000helicalblocks,thehelix-sense

Two- and Three-Dimensional Smectic Ordering of Single-Handed Helical Polymers

SmecticOrderingofHelicalPolymers

Scheme

1

excessesofpoly-L-1(-)andpoly-L-1(+)wereestimatedtobe98.7and96.5%,respectively.18

FurtherAFMobservationsofthebundlestructuresofthepoly-L-1(-)onHOPGrevealeda2Dsmecticlikeself-assemblyofthepolymerchainswithacontrolledspacing(AandBofFigure4).Thelayerstructureisnearlyperpendiculartothedirectionofthepolymerchains.Theaveragelayerspacingofthe2Dsmecticlikeself-assembledpolymerchainsincreasedwiththeincreasingMworrodlengthofthepolymers:5.8,13,and28nmforpoly-L-1(+),poly-L-1(-),andpoly-L-1200(-),respectively(FigureS6).19Wenotethatthe2Dsmecticlikeself-assembliesofthepolymerchainssimultaneouslyguidethe1DarraysofthePtandPdmetalsbondedatthepolymerends,whichmayalsobeusedforfabricatingnanostructuredmaterials.Rodlikehelicalpoly-L-1’swithanarrowMWDappeartobeindispensableforthe2Dsmecticorderingonasubstrate.ConsiderablyclearlayeredimagesofsmecticLCsmallmol-eculesonsubstrateshavealsobeenobservedbyscanningtunnelingmicroscopy,butcontrollablelayerspacingsarelimitedtowithinafewnanometers.20

Polarizedopticalmicroscopyofaconcentratedsolutionofpoly-L-1(-)inchloroform(ca.15wt%)demonstratedthatthepolymerformsatypicalsmecticphase(smecticA)asevidencedbyitsindisputablyclearfan-shapedtexture(Figure4C).Acholesteric-smecticphasetransitioncouldbealsoobservedinaconcentrationgradient(Figure4D).Tothebestofourknowledge,thisisthefirstmicroscopicobservationofalyotropiccholesteric-smecticphasetransitionupondilutionofahelicalpolymerbasedonthemain-chainstiffness.Thedecisiveevidenceofthesmecticlayerstructurewasobtainedfromsynchrotronradiationsmall-angleX-raydiffraction(SR-SAXS)oforientedpoly-1filmspreparedfromaconcentratedsmecticLCchloroformsolutioninamagneticfield(11.75Tfor1day)byslowevaporation.21SR-SAXSofamagneticallyoriented

(18)In1thesameway,theLn,Lw/Ln,helicalsense,andhelicalpitchofpoly-L-200((19)images-)We(Figureandpoly-D-1(+)canbeestimatedfromthehigh-resolutionAFMpoly-preliminarilyS5).

molecular(amixturemeasuredofhigh-molecularhigh-resolutionAFMweightimagesoftheas-prepared

L-1Weweightpoly-poly-L-1(-)andlow-L-1(+))castfromasashownanticipatedinFigureaspontaneousS11,2Dsmecticlikediastereomericabenzenedomainformation.solutiononHowever,HOPG.seemsright-orleft-handedhelicalpoly-layereddomainscomposedofeitherL-1couldnotbeclearlyobserved.2Dsmecticlikelikelythatlayerthemolecularformation.lengthApparently,mayplayadominantroleinsuchIta(20)necessary(a)A.Hara,Ch.;NatureM.;toexplore1990Iwakabe,a,344,228Y.;possibleafurtherthoroughstudyis-Toguchi,spontaneousdomainformation.

230.(b)K.;Smith,Sasabe,D.H.;P.Garito,A.F.;Yamada,

S.;Garc DeBinnig,Schryver,G.ScienceF.C.Chem.1989,245Soc.,43Re-V.45.2003For,32reviews:E.;Ho¨rber,H.;Gerber,,139-150.(c)DeFeyter,Giancarlo,´a,L.;L.Amabilino,C.;Flynn,D.G.B.W.Chem.Acc.Chem.Soc.ReRes.V.20022000,,3133,(d)Pe´rez-,342491--356.501.

(e)ARTICLES

poly-D-1(+)filmshowedasharpreflectionwithaspacingof14.3nminameridionaldirectionperpendiculartotheouterbroadreflectionof2.32nmbeingattributabletothelateralpackingofthepolymer(Figure4E).Thespacingof14.3nmisalmostidenticaltothatdeterminedbyAFM.22TheobservedspacingbySR-SAXSbecomeslongerwhenthemolecularlengthorrodlengthofthepoly-1’sislongerandthelayerspacingsdeterminedbySR-SAXSandAFMareingoodagreementtoeachother(FiguresS8andS9).AtheoreticalstudypredictedthatthesmecticorderingisnotfavoredforrodlikepolymerswithabroadMWD,sincetherodsofdifferentlengthsdonotpackintolayersaseffectivelyastherodofthesamelength.23Infact,poly-1’swithMWDsover1.15nolongershowedanysignofsmecticphases.Transmissionelectronmicroscopy(TEM)ofanultramicrotomedcastfilmofasmecticLCofpoly-D-1(+)showedabandedtexture(Figure4F)witharepeatdistanceofca.14nmcorrespondingtoitssmecticlayerrepeatasobservedbySR-SAXSmeasurements,22eventhoughthebandingrepeatdistancedependsonthelocalcontactanglebetweenthesampleandthediamondknife.24AFMobservationsofpoly-L-1(+)onHOPGalsorevealeda2Dsmecticlikeassemblyofthepolymerchainswithanaveragelayerspacingof5.8(2.2nm(Figure4G),andthepolarizedopticalmicrographofpoly-L-1(+)showedasimilarfan-shapedtextureina15wt%chloroformsolution(Figure4H),offeringconvincingproofforasmecticordering.

Conclusions

Insummary,wehavedemonstratedthatthepresenthelix-senseselectivelivingpolymerizationwiththeµ-ethynediylPt-Pdcatalystunprecedentedlyproducesbothright-andleft-handedhelical,rigid-rodpolyisocyanidesatoncewithpreciselydefinedarchitecturesincludingthemolecularlength,itsdistribution,andhandednessaswell,whichcanbefurtherseparatedintoeachhelixinafacileway.Moreimportantly,thesehelicalpolyiso-cyanidesareproventobeidealbuildingblocksfor2Dand3Dsmecticarrangementsonasubstrate,insolutionandthesolid

(21)Poly-PdD-1(+)wastreatedwithCuClinpiperidinetoeliminatereflectionsresiduesthecouldpriornottobetheobservedSR-SAXSmeasurements,sincethesmectictheterminal

layernotterminalPdresiduespreparedforunderthemagnetic-orientedidenticalconditions;polymersthereasonbearingismetalsclear,atbuttheprobablypolymerduetothehighatomicscatteringfactorofthePd(22)andends(formoredetails,seeExperimentalSectionTwo-dimensionalSupportingInformation).

controlledHOPGspacingsmecticlikewerealsoobservedassembliesinAFMoftheimagespolymerofpoly-chainswitha

D-1(+(23)that(24)Bates,determined(FigureS7).He,M.A.;Frenkel,bySR-SAXSTheaveragelayerspacing14nmisconsistentwith)onD.J.J.andChem.TEM.

Phys.1998,109,61931998S.-J.;,31,Lee,9387C.;-9389.

Gido,S.P.;Yu,S.M.;Tirrell,D.A.Macromolecules

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ARTICLESstate,assistedbyfoursetsofintramolecularhydrogen-bondinghelicalarraysofthependants.Inaddition,thehelicalstructuresofthepolyisocyanidesincludingthehelicalpitchandhanded-nesswereforthefirsttimedeterminedbyhigh-resolutionAFMobservationscombinedwithX-raydiffractionmeasurements.WeanticipatethatthehelicalpolyisocyanidesbearingPtandPdattheendsmayalsobeusedasanoveltemplatetoorganizeone-dimensionalarraysofinorganicmaterialsonthenanoscalebymodificationofthecatalyst,whichmaybeapplicabletothenext-generationoptical,electric,andmagneticdevices.

ExperimentalSection

Instruments.TheNMRspectraweremeasuredusingaVarianAS500spectrometer(Varian,PaloAlto,CA)operatingat500MHzfor1Hand125MHzfor13C,usingTMSastheinternalstandard.TheIRspectrawererecordedusingaJASCOFT/IR-680spectrometer(JASCO,Tokyo,Japan).TheabsorptionandCDspectrawereobtainedina1.0-mmquartzcellusingaJASCOV570spectrophotometerandaJASCOJ820spectropolarimeter,respectively.Thepolymerconcen-trationwascalculatedonthebasisofthemonomerunitsandwas0.2mg/mL.Theopticalrotationsweremeasuredina2-cmquartzcellonaJASCOP-1030polarimeter.SECwasperformedusingaJASCOPU-2080liquidchromatographequippedwithUV-visible(JASCOUV-2070)andCD(JASCOCD-2095)detectors.TwoTosohTSKgelMultiporeHXL-MSECcolumns(Tosoh,Tokyo,Japan)wereconnectedinseries,andTHFcontaining0.1wt%tetra-n-butylammoniumbromidewasusedastheeluentattheflowrateof1.0mL/min.Themolecularweightcalibrationcurvewasobtainedwithstandardpolystyrenes(Tosoh).TheWAXDmeasurementswerecarriedoutusingaRigakuRINTRAPID-RX-raydiffractometer(Rigaku,Tokyo,Japan)witharotating-anodegeneratorandgraphitemonochromatedCuKRradiation(0.15418nm)focusedthrougha0.3mmpinholecollimator,whichwassuppliedata45kVvoltageanda60mAcurrent,equippedwithacurvedimagingplatehavingaspecimen-to-platedistanceof120.0mm.TheX-rayphotographsweretakenatambienttemperature(20-25°C)fromtheedge-viewpositionwithabeamparalleltothefilmsurface.TheSEC-MALSmeasurementswereperformedusinganHLC-8220GPCsystem(Tosoh)equippedwithadifferentialrefrac-tometercoupledtoaDAWN-EOSMALSdeviceequippedwithasemiconductorlaser(λ)690nm)(WyattTechnology,SantaBarbara,CA)operatedat25°CusingtwoTSKgelMultiporeHXL-Mcolumns(Tosoh)inseries.Thescatteredlightintensitiesweremeasuredby18light-scatteringdetectorsatdifferentangles.Thedifferentialrefractiveindexincrement,dn/dc,ofthepolymerwithrespecttothemobilephaseat25°CwasalsomeasuredbyanOptilabrEXinterferometricrefractometer(WyattTechnology).TheAFMmeasurementswereperformedusingaNanoscopeIIIaorNanoscopeIVmicroscope(VeecoInstruments,SantaBarbara,CA)inairatambienttemperature(ca.25°C)withstandardsiliconcantilevers(NCH,NanoWorld,Neufcha tel,Switzerland)inthetappingmode.ThepolarizingopticalmicroscopicobservationswerecarriedoutwithanE600POLpolarizingopticalmicroscope(Nikon,Tokyo,Japan)equippedwithaDS-5MCCDcamera(Nikon)connectedtoaDS-L1controlunit(Nikon).Thesamplesolutionwasplacedonaglassplatewithacoverglasstodeveloptheplanarstructurebeforeobservationofthemicroscopictextureatambienttemperature(20-25°C).TheSR-SAXSmeasurementswereperformedattheInstituteofMaterialsStructureScience,Tsukuba,Japan(PhotonFactory),withsmall-angleX-rayequipmentinstalledonabeamline,BL15A,withtheapprovalofthePhotonFactoryProgramAdvisoryCommittee(No.2006G293).ThewavelengthoftheincidentX-raybeamwas0.1508nm.X-rayphotographsweretakenusingaflatimagingplateplaced2400mmfromthesamplepositionatambienttemperature(20-25°C).TheTEMobservationswereperformedusingaHitachiH-800instrumentoperatedat100kV.Thesamplewaspreparedbycastingaconcentratedsolutionofpoly-D-1(+)inchloro-234J.AM.CHEM.SOC.

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formshowinganLCphaseonapoly(tetrafluoroethylene)(PTFE)petridish.Aftergradualevaporationofthesolvent,thecastfilmwasannealedat170°Cfor2days.Theobtainedcastfilmwasembeddedinepoxyresin(ThreeBond2082C)andultramicrotomedperpendiculartothecastfilmsurface.Thethinfilm(ca.30nmthick)wasthenstainedbyRuO4vaporfor7minbeforetheTEMobservations.

Materials.Anhydrouschloroformandtoluene(watercontent<50ppm)werepurchasedfromAldrichandstoredunderdrynitrogen.THFwasdriedoversodiumbenzophenoneketyl,distilledontoLiAlH4undernitrogen,anddistilledunderhighvacuumjustbeforeuse.The4-isocyanobenzoyl-L-andD-alaninedecylesters(L-1andD-1)8andtheµ-ethynediylPt-Pdcomplex(2)10werepreparedaspreviouslyreported.Polymerization.ThepolymerizationofL-1wascarriedoutinadryglassampuleunderadrynitrogenatmosphereusing2asthecatalystindryTHF.Atypicalexperimentalprocedureisdescribedbelow.MonomerL-1(300mg,0.84mmol)wasplacedinadryampule,whichwasthenevacuatedonavacuumlineandflushedwithdrynitrogen.Afterthisevacuation-flushprocedurehadbeenrepeatedthreetimes,athree-waystopcockwasattachedtotheampule,anddryTHF(3.4mL)wasaddedbyasyringe.Tothiswasaddedasolutionof2inTHF(10µM,0.81mL)atambienttemperature.TheconcentrationsofL-1and2were0.2and0.002M,respectively([1]/[2])100).Themixturewasthenstirredunderadrynitrogenatmosphereandheatedto55°C.After20h,theresultingpolymer(poly-L-1)wasprecipitatedinalargeamountofmethanol,collectedbycentrifugation,anddriedinvacuoatroomtemperatureovernight(286mg,96%yield).

Spectroscopicdataofpoly-L-1:IR(KBr,cm-1):3277(νN-H),1750(νCdOester),1635(amideI),1535(amideII);1HNMR(CDCl3,55°C):δ0.87(broad,CH3,3H),1.26(broad,CH2,14H),1.53(broad,CH3andCH2,5H),4.09(broad,CH2,2H),4.51(broad,CH,1H),4.8-7.7(broad,aromatic,4H),7.9-9.0(broad,NH,1H);[R]25D-995°(c0.1,chloroform);Anal.Calcd(%)for(C21H30N2O3)n:C,70.36;H,8.44;N,7.81.Found:C,70.23;H,8.56;N,7.68.

Fractionation.Theobtainedpoly-L-1(70.8mg)wassuspendedin30mLofacetone,andthemixturewasstirredatambienttemperaturefor3h.Afterfiltration,thefiltratewasevaporatedtodrynessunderreducedpressure,givingpoly-L-1(+)(10.0mg,14%).Theacetone-insolublepolymerwasdissolvedinasmallamountofchloroform,thesolutionwasprecipitatedinalargeamountofacetone,andtheprecipitatewasthencollectedbyfiltration.Afterthisprocedurewasrepeatedagain,thepoly-L-1(-)wasobtained(44.5mg,63%).

Spectroscopicdataofpoly-L-1(+):IR(KBr,cm-1):3279(νN-H),1750(νCdOester),1635(amideI),1535(amideII);1HNMR(CDCl3,55°C):δ0.90(broad,CH3,3H),1.29(broad,CH2,14H),1.62(broad,CH3andCH2,5H),4.11(broad,CH2,2H),4.51(broad,CH,1H),4.9-7.7(broad,aromatic,4H),8.3-9.0(broad,NH,1H);[R]25D+1530°(c0.05,chloroform).Anal.Calcd(%)for(C21H30N2O3)n:C,70.36;H,8.44;N,7.81.Found:C,70.18;H,8.44;N,7.78.

Spectroscopicdataofpoly-L-1(-):IR(KBr,cm-1):3282(νN-H),1750(νCdOester),1635(amideI),1535(amideII);1HNMR(CDCl3,55°C):δ0.87(broad,CH3,3H),1.25(broad,CH2,14H),1.53(broad,CH3andCH2,5H),4.09(broad,CH2,2H),4.51(broad,CH,1H),4.8-7.7(broad,aromatic,4H),7.9-8.9(broad,NH,1H);[R]25D-1615°(c0.1,chloroform).Anal.Calcd(%)for(C21H30N2O3)n:C,70.36;H,8.44;N,7.81.Found:C,70.35;H,8.36;N,7.64.

Poly-D-1wasalsopreparedbythepolymerizationofD-1with2([1]/[2])100)inthesamewayasdescribedabove,andtheacetone-insolublepart(poly-D-1(+))wasobtainedbyfractionationwithacetone.Spectroscopicdataofpoly-D-1:IR(KBr,cm-1):3276(νN-H),1751(νCdOester),1635(amideI),1535(amideII);1HNMR(CDCl3,55°C):δ0.87(broad,CH3,3H),1.26(broad,CH2,14H),1.54(broad,CH3andCH2,5H),4.10(broad,CH2,2H),4.52(broad,CH,1H),4.9-7.7(broad,aromatic,4H),8.0-9.1(broad,NH,1H);[R]25D+1062°(c0.05,chloroform).Anal.Calcd(%)for(C21H30N2O3)n:C,70.36;H,8.44;N,7.81.Found:C,70.36;H,8.32;N,7.64.

Two- and Three-Dimensional Smectic Ordering of Single-Handed Helical Polymers

SmecticOrderingofHelicalPolymers

Spectroscopicdataofpoly-D-1(+):IR(KBr,cm-1):3277(νN-H),1751(νCdOester),1635(amideI),1535(amideII);1HNMR(CDCl3,55°C):δ0.86(broad,CH3,3H),1.26(broad,CH2,14H),1.53(broad,CH3andCH2,5H),4.10(broad,CH2,2H),4.52(broad,CH,1H),4.9-7.8(broad,aromatic,4H),7.9-8.9(broad,NH,1H);[R]25D+1487°(c0.1,chloroform).Anal.Calcd(%)for(C21H30N2O3)n:C,70.36;H,8.44;N,7.81.Found:C,70.00;H,8.62;N,7.42.

Inthesameway,poly-L-150([1]/[2])50)andpoly-L-1200([1]/[2])200)werepreparedbythepolymerizationofL-1with2inTHFat55°Cfor20h,andpoly-L-150(-)andpoly-L-1200(-)wereobtainedastheacetone-insolublepartfromthepoly-L-150andpoly-L-1200,respec-tively.

Spectroscopicdataofpoly-L-150:IR(KBr,cm-1):3281(νN-H),1748(νCdOester),1636(amideI),1536(amideII);1HNMR(CDCl3,55°C):δ0.89(broad,CH3,3H),1.26(broad,CH2,14H),1.56(broad,CH3andCH2,5H),4.12(broad,CH2,2H),4.53(broad,CH,1H),4.7-7.7(broad,aromatic,4H),7.9-9.1(broad,NH,1H);[R]25D-876°(c0.1,chloroform).Anal.Calcd(%)for(C21H30N2O3)n:C,70.36;H,8.44;N,7.81.Found:C,70.13;H,8.28;N,7.99.

Spectroscopicdataofpoly-L-150(-):IR(KBr,cm-1):3279(νN-H),1750(νCdOester),1634(amideI),1535(amideII);1HNMR(CDCl3,55°C):δ0.88(broad,CH3,3H),1.26(broad,CH2,14H),1.54(broad,CH3andCH2,5H),4.11(broad,CH2,2H),4.52(broad,CH,1H),4.9-7.7(broad,aromatic,4H),7.9-9.0(broad,NH,1H);[R]25D-1659°(c0.1,chloroform).Anal.Calcd(%)for(C21H30N2O3)n:C,70.36;H,8.44;N,7.81.Found:C,70.38;H,8.50;N,7.72.

Spectroscopicdataofpoly-L-1200:IR(KBr,cm-1):3276(νN-H),1751(νCdOester),1635(amideI),1535(amideII);1HNMR(CDCl3,55°C):δ0.86(broad,CH3,3H),1.24(broad,CH2,14H),1.53(broad,CH3andCH2,5H),4.07(broad,CH2,2H),4.47(broad,CH,1H),4.8-7.7(broad,aromatic,4H),7.9-9.0(broad,NH,1H);[R]25D-1083°(c0.1,chloroform).Anal.Calcd(%)for(C21H30N2O3)n:C,70.36;H,8.44;N,7.81.Found:C,70.09;H,8.32;N,7.63.

Spectroscopicdataofpoly-L-1200(-):IR(KBr,cm-1):3277(νN-H),1740(νCdOester),1635(amideI),1533(amideII);1HNMR(CDCl3,55°C):δ0.87(broad,CH3,3H),1.24(broad,CH2,14H),1.53(broad,CH3andCH2,5H),4.08(broad,CH2,2H),4.51(broad,CH,1H),4.8-7.7(broad,aromatic,4H),7.9-9.0(broad,NH,1H);[R]25D-1714°(c0.1,chloroform).Anal.Calcd(%)for(C21H30N2O3)n:C,70.36;H,8.44;N,7.81.Found:C,70.34;H,8.36;N,7.70.

WAXDMeasurements.Theorientedhelicalpoly-L-1(-)andpoly-L-1(+)films(ca.20µmthickness)fortheX-rayanalyseswerepreparedfromconcentratedLCbenzenesolutionsinanelectricfieldof6000V/cm.TheWAXDpatternsoftheorientedpoly-L-1(-)andpoly-L-1(+)filmswithdifferentrangesofsensitivitiestoshowboththestrongandweakreflections(FigureS2),wherethemainlayerlineshavebeenindicatedandtheindicesofthereflectionsarelabeled,exhibitdiffuseequatorialreflections,andseveralmeridionalandoff-meridionalreflectionsonthelayerlines,althoughtheonlybroadreflectionswereobservedinthediffractionpatternofpoly-L-1(+)probablyduetoitsrelativelylowmolecularweight.Thereflectionsinthediffractionpatternsofpoly-L-1(-)andpoly-L-1(+)canbeproperlyindexedwithhexagonallattices;a)26.78Å,c)13.05Å,anda)26.45Å,c)13.20Å,respectively.ThespacingsandmirrorindicesofthereflectionsarelistedinTableS1.Althoughwecouldnotobserveameridionalreflectiononthe15thlayerline(0.87Å)evenwhentheX-raymeasurementswereperformedusingacylindricalcamerawiththesamplestiltedca.62°normaltothebeam,themostprobablestructureofthehelicalpoly-L-1(-)andpoly-L-1(+)canbeproposedtobea15/4helixbyconsideringthelayerlineintensitiesobservedinthediffractionpatternsandthedensitymeasurement14andcalculationresults.

SAXSMeasurements.Theorientedhelicalpoly-L-1(-),poly-D-1(+),andpoly-L-150(-)filmsfortheSAXSmeasurementswerepreparedbygradualsolventevaporationofaconcentratedLCchloroformsolutionofeachpolymer(initialconcentration:ca.20wt

ARTICLES

%)inaborosilicateglasscapillarytubeinahighmagneticfield(11.75T)usingaVarianAS500NMRinstrument,afterthepolymershadbeentreatedwithCuClinpiperidinetoeliminatethePdresiduesatthepolymerends,followedbySECfractionation.Wenotedthatthesmecticlayerreflectionscouldnotbeobservedforthemagnetic-orientedpolymersbearingtheterminalPdresiduespreparedundertheidenticalconditions;thereasonisnotclear,butprobablyduetothehighatomicscatteringfactorofthePdmetalsatthepolymerends.

Atypicalprocedurefortheeliminationreactionisdescribedbelow(seeScheme1).Toasolutionofpoly-L-1(-)(41mg)inpiperidine(4mL)wasaddedasolutionofCuClinpiperidine(28.8mM,50µL;2equivtothepolymer)atambienttemperature.Themixturewasthenstirredat120°Cunderadryargonatmosphere.After9h,theresultingpolymerwasprecipitatedinalargeamountofacetonitrile,collectedbyfiltration,andwashedwithacetonitrile.Thepolymerwasthendissolvedinasmallamountofchloroformandprecipitatedinacetonitrilewhichwasrepeatedasecondtime.Theobtainedpolymerhadabroadpolydispersity(Mw/Mn)1.20),andthepolymerwasfractionatedbySECusingTHFcontaining0.1wt%tetra-n-butylam-moniumbromideastheeluent,yieldingpoly-L-1(-)withanarrowpolydispersity(25mg,61%yield,Mn)6.75×104,Mw/Mn)1.04, 364)-21.8)afterbeingpurifiedbyreprecipitationanddriedinvacuoatambienttemperaturefor10h.Inthesameway,thePd-eliminatedpoly-L-150(-)(Mn)2.83×104,Mw/Mn)1.03, 364)-19.9)andpoly-D-1(+)(Mn)5.13×104,Mw/Mn)1.03, 364)+21.6)wereprepared,andthesesampleswereusedfortheSR-SAXSmeasurements.TheresultingPd-eliminatedpolymersgavealmostidenticalCD,absorption,andNMRspectratothoseoftheoriginalpolymers,althoughtheirmolecularweightsandMWDswereslightlychanged.TheseresultssuggestthatthePdeliminationproceduredidnotcauseasubstantialchangeofthehelicalstructuresoftheoriginalpolymers.

SEC-MALSMeasurements.TheSEC-MALSmeasurementswerecarriedoutwithTHFcontaining0.1wt%tetra-n-butylammoniumbromideusedastheeluentattheflowrateof0.5mL/min.Astandardpolystyrene(Mw)30500(PolymerLaboratories,Shropshire,U.K.))wasusedtocalculatethedeviceconstants,suchastheinterdetectordelay,interdetectorbandbroadening,andlight-scatteringdetectornormalization.Poly-L-1(-)andpoly-L-1(+)werecompletelydissolvedintheeluentattheconcentrationof0.1-0.2%(wt/vol)undergentlestirringfor1-2hbeforeinjection.TheevaluationsofthemolecularweightswereaccomplishedusingASTRAVsoftware(version5.1.3.0).Thedn/dcvaluesofpoly-L-1(-)andpoly-L-1(+)intheeluentusedfortheevaluationswere0.1369and0.1367mL/g,respectively.

AFMMeasurements.Stocksolutionsofpoly-L-1,poly-L-1(+),poly-L-1(-),poly-D-1(+),andpoly-L-1200(-)indrybenzeneorTHF(0.015or0.02mg/mL)wereprepared.SamplesfortheAFMmeasure-mentswerepreparedbycasting20µLaliquotsofthestocksolutionsofthepolymers.ThecastingwasdoneatroomtemperatureonfreshlycleavedHOPGunderbenzeneorTHFvaporatmospheres.AfterthepolymershadbeendepositedontheHOPG,theHOPGsubstrateswerefurtherexposedtobenzeneorTHFvaporsfor12or2h,respectively,andthenthesubstratesweredriedundervacuumfor2haccordingtothereportedprocedure.8,16Theorganicsolventvaporswerepreparedbyputting1mLofbenzeneorTHFintoa2-mLflaskthatwasinsidea50-mLflask,andtheHOPGsubstrateswerethenplacedinthe50-mLflask.ThetypicalsettingsoftheAFMforthehigh-magnificationobservationswereasfollows:amplitude1.0-1.5V,setpoint0.9-1.4V,scanrate2.5Hz.TheNanoscopeimageprocessingsoftwarewasusedfortheimageanalysis.

Acknowledgment.WethankProfessorsA.TakanoandY.

Matsushita(NagoyaUniversity)fortheirhelpwiththeSR-SAXSmeasurements.

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ARTICLESOnouchietal.

SupportingInformationAvailable:Molecularmodelingand

calculationsofhelicalstructuresofpoly-L-1(+)andpoly-L-1(-),SECchromatogramsandCDandUV-visspectraofas-preparedpoly-D-1,poly-D-1(+),andpoly-D-1(-),WAXDpatternsandlatticedataoforientedpoly-L-1(-)andpoly-L-1(+)films,IRspectraofpoly-L-1,poly-L-1(-),andpoly-L-1(+)inchloroform,crystallinestructureofL-1,AFM

imagesof2Dself-assembled,as-preparedpoly-L-1,poly-D-1(+),poly-L-1(-)200,poly-L-1(-),andpoly-L-1(+)onHOPG,SR-SAXSpatternofamagneticallyorientedpoly-L-1(-)50.ThismaterialisavailablefreeofchargeviatheInternetat.

JA074627U

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