Two- and Three-Dimensional Smectic Ordering of Single-Handed Helical Polymers(7)

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.

9

VOL.130,NO.1,2008

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

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