Enantioselective crystallization of amorphous Se in the presence of chiral organic molecules

THEBULLETINOFOKAYAMAUNIVERSITYOFSCIENCENo､５１Ａｐｐ２１－２９(2015）

EmntioselectivecrystallizationoramorphousSeinthepresence

o丘chiralor巴anicmolecules

TsukioOhtani,KazuakiIkeda*,NorihiroTnkayanla*,YasuhiroNishida*,ａｎｄYUkiIyama

La6oraroWbrSo〃Ｓｍ/ｅＣ舵伽jrMbc"/〃q/Sとｉｅ"Ｃｅ， ＊Gra伽α/eMzoo/q/Sbje"Ｃｅ， OhU′αｍα伽veハノ〃q/Sbje"Ｃｅ， ノＷｍ－ｃ/２０／-/,Ｋｉｍ-A",ＯﾉtzI〕ﾉzJma700-0005,､ﾉZIPα〃 （ReceivedSeptember25,2015;acceptedNovember9,2015） WehavepreviouslyobserevedthatwhenamorphousSe(a-Se)wasexposedtoorganicfluids,thea-Sewastrans‐ fbrmedintoahexagonalSe(h-Se)oranamonoclinicSe(”"２－Se),correspondingtothedielectricconstantoforganic nuids･Ｉｎｔｈｅｐｒｅｓｅｎｔｓｔｕｄｙｗｅｆｂｕｎｄｔｈａｔｔｈea-Sewasenantioselectivelycrystallizedintotheﾉｂ－Ｓｅｏｒｔｈｅｃｗ"-Seby beingexposedtochiral2-octanolatroomtemperature;theh-Sewasobtainedin(R)‐(‐)-2-octanol,andthezw"-Sein (3)-(+)-2-0ctanol・Similarbehaviorswereobservedunderthevaporsof2-octanolaswellasproline・Thisphenomenon ishardlyexplaine｡,becausetheenantiomershavethesamechemicaIandphysicalpropertieswitheachothe囚except fOrtheopticalrotation･TheopticalrotationisnotresponsiblMOrthisphenomenon，becausethisphenomenonwas observedevenintheabsenceoflight･Thephenomenonwasalsoobservedwhenthesamplesofvariousmakerswere employed,indicatingthattheqMityofthesampleshasnotresponsibilityfbrit・Theoriginisnotclearedyet・Ifthis phenomenonisintrinsicnatuｒｅｔｏｔhepresentsystem,ｔｈｉｓｃｏｕＩｄｂｅｔｈｅａｎｓｗｅｒｔｏｔｈｅ“Ozmaproblem''proposedby Gardnel1whichinquiresthewaytocommunicatethemeaningof“leftorright'，onlybyalanguagetothealiens． Keywords:enantiomer;enantioselectivity;chirality;crystallization;amorphousselenium;hexagonalselenium;monoclinic selenium;adsorptionoforganicmolecules;secondaryalcohol;2-octanokproline. 1．Introduction Elementalseleniumhasmanypolymorphs：ａｍｏｒ‐

phous（a-Se)''2)，hexagonal（ortrigonal）

(h-Se)3),αmonoclinic（α邑加-se)4)，βmonoclinic，

Y-monoclinic，rhombohedral，ortholhombic，etc・Ｔｈｅ ﾙｰSephaseisthemoststablephase，whichcanbe obtainedbyslowlycoolingmoltenSe・Ｔｈｅａｍ－Ｓｅ ｐｈａｓｅｉｓｏｂｔａｍｅｄａｓａｍｅｔａstablephasebyevapora‐ tionfiPomCS2solution，andeasilyconvertstothe h-SephasebywanningBecauseofthehighphoto-conductivity,theelementalseleniumhasbeenwidely usedinmanyapplicationssuchasphotocells,xerog‐ raphy,electricalrectifiers,etcTheSeisalsousedfbr coloringglassesredorreddishyellow・Recentim-portantuseoftheSeisaｈｉｇｈsensitivecamerambes usingHARP（High-gainAvalancheRushingamor‐

phousPhotoconductor)imagingdevices5)．

(a）

(b）

FigurclCIystalstructuresofSe:（a)hcxagonalselenium (/z-Se);(b)α色monoclinicselenium(α皀加-Sc)． Figurelgivesschematiccrystalstructuresofthe h-Se(a)andtheαしm-Se(b).ThM-Secrystalconsists ofparallelmfinitechainsofSeatoms，ｗｈｅｒｅＳｅａｔ‐ omsarealTangedinscrew-likespiralsalongthe

2２ _{TsukioOHTANLKazuakilKEDA,NorihiroTAKAYAMA,YasuhiroNIsHIDAandYukilYAMA}

clystallmecaxis3)．Ｔｈｅｃｈａｍｓｃａｎｂｅｒｉｇｈｔ－ｈａｎｄ

ｓｃｒｅｗｓｏrlefi-handscrews,bringmgaboutthechiral‐

ｉｔｙｔｏｔｈｅｃｌｙｓｔａＬＴｈｅａｗｌ－Ｓｅｐｈａseisamolecular

clystal，beingcomposedofbuildingblocksofSe8

moleculesarrangedinacrownshape4).Theh-Seisa

semiconductorandthecw7z-Seaninsulator6)．

Wehavepreviouslyfbundthatthea-Sewascrys-tallizedintotheh-Seorthea-m-Se,whenexposedto

variousorganicfluidsatroomtemperaturefbrabout

lOdays7,8)．Figure2(a)showstheX-raydmaction

(XRD)patternofthea-SaWhenthea-Sewasex‐ posedtoacetoneliquidatroomtemperaturefbrlO days,thea-Setransfbrmedtotheh-Se,ａｓｓｈｏｗｎｉｎ Ｆｉｇ２（b)．Ｔｈｅα-"-Sewascrystallizedfomthe a-Sembenzeneliquid,asshowninFig2(c)．

Scanningelectronmicroscopy（SEM）ｉｍａｇｅｓｏｆ

ａ－Ｓｅ,ﾉｶｰSeanda-"z-SearegivenmFig3(a),(b)and (c),respectivelyThea-Sepossessesangularand irregularmorphology、Inacetone，thea-Sewas cIystaUizedintomultiplefibroussingleclystalsofthe

ｶｰＳｅｗｉｔｈｃａ・S0umoflengthandca､０.ｌＵｍｏｆｄｉ‐

ameter(Fig.３（b)).Inbenzenethea-Sewastrans‐

fbrmedtothea-腕-Secrystalswithmany-facedpoly‐

hedralmorphologywithmeandiametｅｒｏｆｌＯｕｍ (Fig.３(c)).Theselectivecrystallizationofthea-Se wasobservedfbrmanyotherorganicliquidsNore‐ actionoccun･edinwaterThisphenomenonwasalso observedevenintheabsenceoflight・ Aclearrelationexistsbetweenthetypeofgrown phaseandthedielectricconstanteoftheorganicfIu‐ ids・Ｔｈｅ/z-Seclystalsweregrownintheliquidswith an8greaterthanca、４，ｅ､gacetone（ｅ＝20.7)， methanol（ｅ＝32.63),ethanol(８＝２４５５),acetoni‐ trile（８＝37.5),benzonitrile（８＝25.20),pyridine (ｇ＝12.3),quinoline(８＝9.00),ａｎｉｌｍｅ(８＝6.89)， piperidme(８＝5.8),diethylether(８＝4.3),etc､The a-m-Secrystalsfbrmedintheliquidswithan81ess thanca､３，ｅ・gbenzene(８＝2.27),hexane(８＝1.89)， cyclohexane(８＝2.02),toluene(ｅ＝2.38),etc・ MorethanlOOyearsago，Saundersfbundsimilar selectivecrystallizationofthea-Seinvariousorganic

liquids9).Hisresults,however,aredifferentfiPomours

fbrsomeorganiccompounds，probablybecauseof thelackofX-raydiffTactionmethodinhisexperi-mentsHeclaimedthattheprecipitationfi･omtheor‐ ganicsolutioncausesthecrystalgrowthofSeSince Saunders，work，ｔｈｅｒｅｈａｓｂｅｅｎｎｏｒｅｐｏｒｔｏｎｔｈｉｓ ｐhenomenonuntilourpublication． Ｉｎｔｈｉｓｍｅｔｈｏｄｗｅｗｅｒｅａｂｌｅｔｏｏｂｔａｉｎfibrous clystalsofh-Se、Thesenanowireswerefbundto

showtheelectricalresistivityhighlysensitivetothe

volatileorganicgases,leadingtothedevelopmentof

agassensorcapableofdetectmgvariousorganic

gasesatroomtemperature'0,11)． ｐＬ’』鰯』 庫葛壁彊回寓鐘田色○日

ｌｉＷ'ｌｌｉｉ；Milll1'i'M',,,&

倉彊勘式や局）鰯雪質芯這 Ｏｄａｖｓｉｎａｃｅｔｂ ４厘(、、２ 費冨伏字肩）時》誘何“》ロ宮 ５２０４０６０８０ ２０(degI1ees） Figure2XRDpattemsofSc:（a)startingamorphousSe (a-Se);(b)theh-Seobtainedbyexposingthea-Setoace‐ toneatroomtcmperaturefbrlOdays;(c)theα-脚‐Ｓｅｏｂ‐ tainedbyexposingthea-Setobcnzencatroomtempera‐ turefbrlOdays． amorphous Se iｎａｃｅｔ inbenzene

i篝i1iiii騨總

hexagoBRalSe αmolmclinicSe Figure3SEMimagesofSeparticles;(a),(b)and(c)inthe figurecorrespondstoFig2（a),(b)ａｎｄ（c),respectively： (a)thea-Se;(b)the"-Sc;(c)theawz-Se．

EnantioselectivecrystallizationofamorphousSeinthepresenceofchiralorganicmolecules 2３ Thepresentreactionstookplaceevenunderthe vaporsoforganicliquidsorsolids，suggestmgthat organicfluidsdonotactassolvent,buttheadsorbed organicmoleculesplayacatalyticrolefbrthecrystal growthSuchasimationisschematicallyillustrated mFig4，Ifadsorbedorganicmoleculeshavethe higherdielectricconstant，ｔｈｅstrongelectrostatic fieldwouldbelocaUyinducedbytheadsorbedmol‐ eculesonthesurfaceofSeparticles、Suchstrong electrostaticfieldwouldacttostimulatethecrystal-lizationofh-Se,becausM-Sehasarelativelyhigh

dielectricconstantalongthecaxis(Ｍｃ＝10-13)'2)．

Inthepresentstudywehaveobservedtheenanti‐ oselectivecrystallizationofthea-Semthepresence ofchiralorganicmoleculesof2-octanolandprolｍｅ．

(a）

ＨＨＭ 織処… ● IＣ

OrganiCSe

liquM Ｄｒｐ２ Figure5Schematicillustrationofexperimentalsetupfbr thecrystallizationofa-Seinorganicliquid(a),andunder thcvaporoforganiccompound(b)． 3．Results 3-1CrystaUizationofSeinthepresenceofchiral secondaryalcohols

Theenantiomericconfigurationofthesecondary

alcoholsisrepresentedmFig6,wheretheasymmet-riccarbonatomisdesignatedbytheasterisk が _6十

鯵

ｎ＝２ J 4 S

CnHZIrI-l．

７ ８ Z-bUX1Zm⑨l 2-pe“aHBOl ZPhe亜TdDH Z-heptmmi 2．｡＄輯IHol 聾征⑪”…Ｈ ２･deczlml Ｈ 6十 6十 Figure4Schematicillustrationofadsorbedorganicmole‐ culesonthesurfaceofamolphousSe．

Ｈ３Ｃ

ＨＯ

２．Experiments

TheexperimentalsetupsareillustratedmFi9.5．

Thea-Sepowderwasplacedmtoorganicliquidma

glasscapsule,andwasaUowedtostandatroomtem-peraturefbracertamperiodoftime(Fig.５(a)).The

a-Seshots(RareMetallicCoLtd,99.9999％ｍｐｕ‐

rity)weregroundintopowderfbnnbyusinganagate

mortar、hordertomvestigatetheenantiomericef

fectsonthecrystallizationofthecJ-Se，theexperi‐

mentswerecalTiedoutusingthechiralsecondaryal‐

coholssuchasthe2-octanol(Sigma-AldrichColpo‐

ratio､,９９％mpurity).Inaddition,thea-Sepowders

wereexposedtothevaporsofchiralolganicliquids orchiralorganicsolidsasshownmFi９５(b).Ob-tainedsampleswereanalyzedbyanX-raydifffaction (XRD)techniqueusmgaRigakuRINT2500mstru‐ memwithCuKqradiation・Themorphologyofthe sampleswasobservedbySEMusingaJEOL JXA-8900instrument． Figure6Enantiomericconfigurationofsecondalyalcohols・ Theasymmetriccarbonatomisdesignatedbythcasterisk

Ｆｉｇｕｒｅ７ｓｈｏｗｓＸＲＤｐａｔｔｅｒｎｓｆｂｒＳｅｏｂtainedby

exposingthea-Setochiralsecondaryalcohols

(2-butanol,Z-pentanoLand2-hexanol)fbrlOdaysat

roomtemperature・ＴｈｅcJ-Sewastransfbrmedintothe ﾙｰＳｅｆｂｒａｌｌｃａｓｅｓＦｉｇｕｒｅ８ｓｈｏｗｓｔｈｅｒｅsultsfbr 2-heptanol，２－octanoland2-nonanoLInthe

(S)-2-heptanol，ｔｈｅﾙｰSewasdominantlygrown，

whilethereactionwasscarcelyobservedmthe (R)-2-heptanoLForthe2-octanol，ｔｈｅカーSｅｗａｓ ｇｒｏｗｎｍｔｈｅ（R)-2-octanolandthecwlT-Seinthe (5)-2-octanol，bemgoppositetothoseofthe

2-heptanoLForthe2-nonanol,ｔｈｅｃｗ"-Sephasewas

dominantlyobtainedfbrbothenantiomers Wecarriedouttheexperimentsfbrthe2-heptanol

TsukioOHTANI,KazuakilKEDANorihiroTAKAYAMA,YasuhiroNIsHIDAandYukilYAMA 2４ andthe2-octanolfbrlongertime・Figure9shows XRDpattemsfbrSeobtamedbyexposingthea-Seto the2-heptanolfbr2yearsatroomtemperature､The h-Secrystalswereobtainedfbrbothenantiomers、 SEMimagesofcorrespondmgsamplesaregivenin Fi９．１０；thefibroussinglecrystalsofルーSewere growniｎ（S)-2-heptanol,ａｎｄtheneedlelikeA-Se crystalsm（R)-2-heptanoLForthe2-octanol，ｔｈｅ ｓａｍｅｒｅｓｕｌｔｓｓｈｏｗｎｉｎＦｉｇ８ｗｅｒｅｏbservedafter2 years，whichwillbedescribedinmoredetailinthe nextsectionForthe2-nonanol,theα-"Z-Sewasob‐ tainedafter2years． （》漬。，名画）画扇５》員 ０２０４０“８０ ２８(degree） Figure9、XRDpatternsofSeobtainedbyexposingthe a-Setochiral2-heptanolfbr2yearsatroomtemperature． )-2-bｕｔｍｏｌ （》這二・豊⑤）ご｛曾婁三 (S)-(+>2-pemtanol ＦｉｇｕｒｃｌＯＳＥＭｉｍａｇｅｓｏｆＳｅｏｂｔａｉｎｅｄｂycxposingthe a-Sefbr2yearsatroomtemperatureto(S)-2-heptanol(a） and(R)-2-heptanol(b)． ､Cｌ ＯＺＯ４０“lHKb２０４０“８０ ２８(degree） FigUre7・XRDpatternsfbrSeobtainedbyexposingthe a-SetothesecondaryalcoholsfbrlOdaysatroomtemper‐ aturc:(a)(Sﾘｰ2-butanol,(SﾉｰZ-pentanol,and(SﾘｰZ-hexanol； (b)㈹-2-butanol,(Rﾉｰ2-pentanol,and(iRﾉｰ2-hcxanoL 3-ZEnantioselectivecrystaIlizatiｏｎｏｆａｍｏｒｐｈｏｕｓ ＳｅｉｌｌｔｈｅｐｒｅｓｅｎｃｅｏfchiraI2-octanol FigurellshowsＳＥＭｉｍａｇｅｓｏｆＳｅｃｒｙｓｔａｌｓｏｂ‐ ｔａｍｅｄｍｔｈｅ２－ｏｃｔａｎｏｌｆｂｒｌＯｄａｙｓａｔｒoomtempera-ture:(a)inthe(S)-2-octanol,(b)ｍthe(R)-2-octanoL Inthe(S)-2-octanol,thea-Sewasscarcelyreacted， ｗｈｉｌｅｆibrousandneedlelikecrystalswerｅｇｒｏｗｎｉｎ (R)-2-octanol,whichareparalleltoXRDobserva-tionsshownmFig8． （》這回・曇愚）ご一召の》三 8ｍ 6０ 6０８●２０ ２８(degree） 4０ 4３ ＦｉｇｕｒｅｌＬＳＥＭｉｍａｇｅｓｏｆＳｅｏｂｔａｉｎｅｄｂyexposingthe a-Setothe2-octanolfbrlOdaysatroomtemperature:(a） in(8)-2-octanol,(b)in(R)-2-octanoL ZＯ 0 patternsofSeobtaincdbyexposingｔｈｅ Fｉｇｕｒｃ８ＸＲＤ α-Setothechiralsccondaryalcohols(2-heptanoL2-octanol 2-nonanol）fbrlOdaysatroomtemperature：（a） Sconfiguration,(b)R-configuration． Ｆｉｇｕｒｅｌ２ｓｈｏｗｓＸＲＤｐａｔｔｅｍｓｏｆＳｅｏｂｔainedby exposingthea-Setothechiral2-octanolfbr30days．

(a）

－－'し

S)-(+)-2-hept四,０１ _AjLjL～w､－－■■■■ 幸■－

EnantioselectivecrystallizationofamorphousSeinthepresenceofchiralorganicmolecules

2５

ＴｈｅルーSephasewasalmostcompletelyclystalizedin

(R)-2-octanoLwhilemthe(8)-2-octanolthecrystal‐

lizationwasscarcelyprogressedyeｔＸＲＤｐａｔｔｅｍｓｏｆ

Ｓｅａｆｔｅｒｌ５０ｄａｙｓｏｆｄippingin2-octanolandthe

correspondingSEMimagesareshownmFigs」３

ａｎｄｌ４，respectively・Thecrystallizationofthe

cw"‐Sephaseisprogressedmthe(5)-2-octanoL （》冨宮ロ』面）昏扇息一屋 （｝旨。．●』句〉鈎扇５一三

(a）

(５Ｍ+)-2-octanol 30days 戸国項扇）善曾曾昌 （》賓喜．二局）濁扇息一三 2０ ４０６０ ２９(degree） 8０

Figurel5・XRDpatternsofSecrystalsafierexposingthe

a-Setothe2-octanolatroomtemperaturefbr2years:(a)ｉｎ

the(5)-2-octanol,(b)inthe(R)-2-octanoL ２０４０６０８０ ２８(degree）

Figurel2XRDpattemsofSeobtainedbyexposingthe

a-Seto(S)-2-octanol(a)and(R)-2-octanol(b)fbr30days

atroomtemperature． 曽冒．Ｐ肩）宮召豊 （】冨弓名呵）ご湯屋９口 ２０４０６０８０ ２８(degree） Figurel3・XRDpattemsofSeaftercxposingthea-Sefbr

l50daysto(S)-2-octanol(a)andto(R)-2-octanol(b)．

Ｆｉｇｕｒｅｌ６ＳＥＭｉｍａｇｃｓｏｆＳｅｃｌｙｓｔａｌｓｏbtainedbycxposing

thea-Seto2-octanolfbr2ycars:(a)a-m-Secrystalsinthc

(5)-2-octanol;(b)/z-Seclystalsinthe(R)-2-octanoL

iii議鑪iiili薑鑿

鐘慧霧1篝;雲iv……

Ｆｉｇｕｒｅｌ５ｇｉｖｅｓＸＲＤｐａｔｔｅｍｓｆｂｒＳｅｓａmplesob-tainedbyexposingthea-Setothechiral2-octanolfbr

２years・Ｔｈｅｌａｒｇｅａｍｏｕｎｔｏｆｔｈｅａ－Ｓｅｐｈａｓｅwas

transfbrmedtotheα上腕‐Sephaseinthe(S)-2-octanoL

althoughthea-SephasestillremainsFigurel6

Ｆｉｇｕｒｅｌ４ＳＥＭｉｍａｇｅｓｏｆＳｅ・Thesamplescorrespond

tothosei、Ｆｉｇ．１３．

(わ）

Ｉ (R)-2-octanol 1５０． Aｌ ays JR」向

TsukioOHTANLKazuakilKEDA,NorihiroTAKAYAMA,YasuhiroNIsHIDAandYukilYAMA 2６ 3-3Enantioselectivecrystallizationundertheva-porsofZ-octanolandproline Figurel8givesSEMimagesoftheSesamples obtainedbyexposingthea-Setothevaporsofenan‐ tiomersof2-octanolfbr300daysatroomtempera-ture､Ｔｈｅｃｗ"-Secrystalsandtheh-Secrystalswere obtainedunderthevapoｒｏｆｔｈｅ（S)-2-octanoland (R)-2-octanoLrespectively・Theseresultswereidenti‐ fiedbytheXRDmeasurements，whilethesmall amountofh-Sephasecoexistswiththemajorityof cMZ-Sephaseunderthevaporof(S)-2-octanol． showstheSEMimagesofcorrespondiｎｇｓａｍｐｌｅｓ

ｓｈｏｗｎｍＦｉｇｌ５・Thepolyhedralaとm-Secrystals

weregrownmthe（S)-2-octanol；thesizeofeach

crystalisaboutseverallmindiameter・Themultiple

fibrousA-Secrystalswereobtainedfbrthe

(R)-2-octanol;morethan501LLmlengthandabout0.1

11mdiameter・Theseobservationsoftheenantioselec‐

tivityareparalleltotheXRDpatteｍｓｉｎＦｉｇｌ５・

Ｔｈｅａ－ＳｅｗａｓｔｒａnsfbrmedtotheｶｰSe，whenex-posedtotheachiral2-octanol

Theseobservationsmaypossiblybecausedbythe

slightdifferenceinthequalitybetweeneachofenaL

tiomers・Wehaveperfmned，thus，theexperiments

usingvariouscombinationsofthea-Seandthe

Z-octanolmadeindifferentmakers：ｔｈｅｃＪ-Se；Sig‐

ma-AldrichCorporation,WakoPureChemicallndus‐

tries,RareMetallicCo.,andNacalaiTesque,Inc.:the

Z-octanol；Sigma-AldrichCorporationandWako

PureChemicalhdustries、Ｆｉｇｕｒｅｌ７ｓｈｏｗｓＸＲＤ

ｐａｔｔｅｒｎｓｏｆＳｅｏｂtainedbyusmgthea-Se（Nacalai

Tesque,IncJandthechiral2-octanol（WakoPure

ChemicalIndustrieS)fbrlOdaysatRTThereaction

wasscarcelyobservedmthe（S)-2-octanoLInthe

(R)-2-octanoltheA-Sephasedominantlyappeared，

accompaniedbyasmallamountoftheαと腕-Sephase

Theseresultsareessentiallyidenticaltotheresults

obtainｅｄｂｙｕｓｉｎｇｔｈｅａ－Ｓｅ(RareMetallicCoLtd.）

andthe2-octanol（Sigma-AldrichColPoration)．In

othercombinationsofstartingsamplesofdifferent makersthesimilarresultswereobtained． Figurel8・SEMimagesoftheSeobtaincdbyexposingthe a-Setothevaporofchiral2-octanolatroomtcmperaturc fbr300days:(a)in(S)-2-octanol;(b)in(R)-2-octanoL Theenantioselectivecrystalgrowthwasalsoob-servedinthevaporofproline､Figurel9givesXRD

patternsofSecrystalsobtamedbyexposmgthe

a-Setothevaporofapairofenantiomersofproline

fbr410days・Figure20exhibitsSEMimagesofSe

crystalscorrespondingtothesamplesgivenin

Figl9：（a）ｉｎｔｈｅＬ－(-)-prolineand（b）ｍｔｈｅ

Ｄ－(+)-prolineTheaLm-SeandルーSecrystalswere

grownfbrthevaporofL-proline，andD-prolina

respectively．

(S)-2-octanol

(a）

くこ、 巨 雪 _{（》富二・二息）画一の扇這『} 學冨）昏洞５》星 駒 q(Ｉ 4０ ＳＩＯ２０

(b）

(R)-2-octanol

２０４０６０８０ ２８(degree） ５２０４０６０８０ ２８(degree） 0 Figurel9・XRDpatternsofSecrystalsobtaineｄｂｙｅｘｐｏｓ－ ｉｎｇｔｈｃａ－Ｓｅｔｏｔｈｃｖaporoftheprolinefbr410daysat roomtemperature:(aル(-)‐proline,(b)Ｄ－(+)-proline．

Figurel7・XRDpatternsofScobtainedbyexposｉｎｇｔｈｅ

ａ－Ｓｅ(NacalaiTbsque,Inc.）tothechiral2-octanol（Wako PureChemicallndustries)fbrlOdaysatroomtemperature．

2７ EnantioselectivecrystallizatioｎｏｆａｍｏｒｐｈｏｕｓＳｅｉｎｔｈｅｐｒｅｓｅｎｃｅｏｆｃhiralorganicmolecules ditionfbrthepresentenantioselectivecrystalgrowth Themostnoticeableisthattheclystallizationraｔｅ ｏｆｔｈｅｃｗ－Ｓｅｉｎｔｈｅ（S)-2-octanolisquiteslow， comparedwiththatinotherorganicfluidsproducing thecw"Se，suchasbenzene・Thea-Seseemstobe almostinerttothe(S)-2-octanoLThiswouldsuggest thattheelectrostaticfieldmducedbyadsorbed (S)-2-octanolmoleculesonthesurfaceofthea-Se particlesiseffectivelysuppressedbysomecauses Oneofthecauseswouldbethatthealkylchamdirec‐ tionofthe(S)-2-octanolisnotperpendiculartothe surfaceofthea-Separticles，butparalleltoitThe otheristhatthemoleculesofthe(s)-2-octanolare adsorbedmantiparallelmanner・Bothmechanisms wouldacttodiminishthelocalelectrostaticfieldon thesurface・Butonecannotexplamwhysuchsitua‐ tionsoccuronlyfbrtheSconfigurationltismore plausible，thus，thatthea-Sehasanyresponsibility fbrthisphenomenonTheunknowncrystalstructure ofthea-Sewouldcorrelatewiththechiralorganic Huids,causmgthisphenomenon Themodificationofthea-Seconsistsofacompｌｅｘ ｃｏｍｂｍａｔｉｏｎｏｆＳｅａｔｏｍｓｆｂｒｍｉｎｇｃhainsandclosed rmgsltisbelievedthattheshort-rangeordermgof thechainsissimilartothestructureoｆｈ－Ｓｅａｎｄｔｈｅ

ｒｉｎｇｓｒｅｓｅｍｂｌｅｔｏｔhosemthemonoclinicSer4)．We

recallherethattheカーSehasthechiralityoriginating h･omthehelicalchamsThisleadsustoconsiderthat therewouldbeasymmetrybreakmtheh-Selike chainsexistingintheq-Se,bringingabouttheenan‐ tioselectivecrystallization，withcorrelatingtothe chiralorganicmolecules・ＷｅｈａｖｅｃalTiedout,thus， thefbllowingexammations，fbcusingonthecarefUl preparationsofthea-Se． Figure20SEMimagesofcw形Secrystals・Figs.（a)ａｎｄ (b)corrcspondtoFigl9(a)and(b),respectively． ｌｔｉｓｔｏｂｅｉｎｔｅｒｅｓｔｅｄｔｈａｔｔｈｅｃｈｉｒａlprolineis usedasanenantioselectiveorganocatalyst，which worksasthechiralcatalystiｎａｎＡｌｄｏｌｒｅａｃ‐ tionl3)，althoughthemechanismisdiffbrent fromthatofthepresentreactions・ ItwassometimesobservedthattheかＳｅａｎｄｔｈｅ ｃｗ"Seclystalsweregrownunderthevapｏｒｏｆ (+)‐camphorand(-)-camphoMespectivelyTheen‐ antioselectivitywasnotobservedinunderthevapors ofchiralorganiｃｓｏｌｉｄｓｓｕｃｈａｓａｓｐarticacid,alanine， serme,menthoLtartaricacid,galactose,limonene, Noe，sreagent，etc・Theawo-Seclystalswereob-tamedmallcases． 4．Discussion Thea-Sewasobservedtoshowtheenantioselec‐ tivecrystallizationbybeingexposedtothechiral Z-octanolatroomtemperaturaThesimilarenanti‐ oselectivecrystallizationwasobservedundertheva-porsofchiral2-octanolaswellaschiralprolmeThe originofthisphenomenonisquitehardlyexplained， becausetheenantiomershavethesamechemicaland physicalpropertieswitheachother，exceptfbrthe opticalrotationThisphenomenonwasalsoobserved intheabsenceoflight,indicatingthattheopticalro‐ tationisexcludedffomthecandidateoftheorigin Asmentionedabove,ｔｈｅｋｉｎｄｏｆｇｒｏｗｎｐｈａｓｅｄｅ‐ pendsonthedielectricconstanteoftheorganicmol‐ eculesThestrongelectrostaticfieldlocallyinduced bytheadsorbedorganicmoleculesonthesurfaceof a-Secouldstimulatethecrystallizationoftheh-Se phasehavmgthehigherevalueThe8valueofthe secondarｙａｌｃｏｈｏｌｉｓ16.72,13.20,11.06,9.25,7.80, and666fbr2-butanol,Z-pentanoL2-hexanol, 2-heptanol，２－octanoland2-nonanol，respectively The8valueof780ofthe2-octanolissituatednear theborderofthecriterionfbrcrystalgｒｏｗｔｈｏｆｔｈｅ ﾙｰＳｅｏｒｔｈｅｃｗ?z-Se・Thiscouldbethenecessarycon‐ [Preparationofthea-SebyquenchingthemoltenSe］ ThepresentXRDmeasurementsrevealedthatthe conmerciala-Sepossessestheamorphousmodifica‐ tionButthecommercialsampleswouldcontainan unknowncharacteristicstructure,ｂｅｃａｕｓｅｗｅａｒｅｎｏｔ ａｂｌｅｔｏｋｎｏｗｔｈｅｐｒeparationmethodofthemWe prepared,thus,theamolphousSebyquenchingmoｌ－ ｔｅｎＳｅ(thestartingSe:RareMetallicCo.,Ltd.)けｏｍ ６７３Ｋｔｏ２７３Ｋ・Usingthisa-Se，wecalTiedoutthe experimentsfbrthechiral2-octanoLFigure21shoｗｓ ＸＲＤｐａｔｔｅｒｎｓｏｆＳｅｏｂｔａｉｎｅｄｂｙｅｘｐosingthepre‐ pareda-Setothe2-octanol(Sigma-AldrichColpora‐ tion)fbrlOOdaysatroomtemperature,Althoughthe

2８ _{TsukioOHTANLKazuakilKEDA,NorihiroTAKAYAMA,YasuhiroNIsHIDAandYukilYAMA} α-"-Sephasecoexistswiththeh-Sepｈａｓｅｆｂｒｔｈｅ (5)‐Z-octanoLtheresultsareessentiallysimilarto thoseobtamedbyusingthecommerciala-Se・These resultsshowthatthepresentenantioselectivecrystal‐ lizationdoesnotdependonthesamplepreparation processes． 意趣辱○令閏〉野漫画ｇ圏

UjliilififiLf#,fHIWiiiIllil鬘

例…｝脇…Ｉｓｏ

_{－－－ｊＬ…jL-鍬ﾑｰﾍｰﾍｰﾊ－－－}

amoxphouSSe(q…歯Ｇｄ姉m4o`℃） ０鋼鋤“餌 ２９(dg8陣巳） Figure22・XRDpattemsofSeobtainedbyexposingthe a-Seto2-octanolfbr66days,wherethea-Sewasmilledin anagatemortarclockwise(a),andcounterclockwise(b)． 《嚢邑旬・曇幽甸》舜鐘頓面⑰》■】

［Isthisphenomenonananswertothe“Ozmaprob‐

lem"?］ Ifthepresentphenomenonistrulyintrinsicnature tothissystem，wehaveobtainedthenewmeansto distinguishthechiralityoforganiccompoundswith-outobservationequipment・Inadditionwecan

communicatetheconceptofrightorlefttoanyper‐

sononlybyalanguage､Gardnerproposedthe“Ozma problem,，，whichasksthewaytoconnnunicatethe meaningof"leftorright，，onlybyalanguagetothe

alienslivinginfarawayspace17)．Thisproblemwas

solvedbytheobservationsofnon-preservationofthe

paritymtheβdecayofCo6oatoms18).Thisistheso‐

lutionbythephysics・Thepresentobservationofen‐ antiosectivitywouldbetheanswertothisproblem 丘omthefieldofchemistry､Wecaninfbnnthealiens theexactconceptoftheleftasfbllows.“Exposethe amolphousSetoeachofenantiomersof2-octanoL andobservetheopticalrotationofthechiral 2-octanol，whichproducedthehexagonalSeThe observedrotationdirectionistheleft.，， Thecomnunicationtothealienswouldbealso possiblemthefbllowingcaseJfthestartingenanti-omersofthe2-octanol(orproline)andthea-Seare wellidentifiedmcludingpossiblyexistingimpurities， thepresentobservationscanbealwaysreproducedJf thealiensareinfbrmedofthesamepreparationpro‐ cessesof2-octanol(orproline)anda-Seasours,they canknowtheexactconceptofrightorleftonlybya languageffomus・Thedetailedpreparationmethodof presentorganiccompoundsshouldbeneededagain ０２０繍鰯８０ ２“degH忠勤 Figure2LXRDpatternsofSeobtainedbyexposingthc a-Seto2-octanolfbrlOOdaysatRnusingthea-Sepre‐ parcdbyqucnchingthemoltenSefroｍ６７３Ｋｔｏ２７３Ｋ． [Effectsofmillingturndirectionofthea-Se］ Inthepresentstudyweobtainedthepowdered a-SebyclockwisemillmgoftheSeshotsusingan agatemortarｂｙｈａｎｄ・Theonedirectionofthemill‐ ｉｎｇｍｎｗｏｕｌｄｂｒｅａｋｔｈｅｓｙｍｍｅｔｒｙofh-Selike chainsexistinginｔｈｅａ－ＳｅＴｈｅｓｙｍｍｅｔｌｙｂｒｅａｋｍｇ ｂｙｏnedirectionofstirringwasobservedmaqueous

solutionofNaClO315''6)．Weground，thus，thea-Se

shotsclockwiseorcounterclockwisemtheagate mortar、Ｆｉｇｕｒｅ２２ｓｈｏｗｓＸＲＤｐａｔｔｅｒｎｓｏｆＳｅｏｂ‐ tainedbyexposingthea-Setothechiral2-octanolfbr 66daysatroomtemperature，wherethea-Sewas previouslymilledintheagatemortarclockwise(a)， andcounterclockwise(b)．Inbothdirectionsofturn thesameresultswereobtamed；ｔｈｅαと腕‐Secrystals wereobtamedmthe(S)-2-octanolandtheh-Secrys‐ talsinthe(R)-2-octanoL Asaresult,ｗｅｗｅｒｅｎｏｔａｂｌｅｔｏｆｉｎｄｔｈｅｏｒｉｇｉｎｏｆ thepresentenantioselectivecrystallizationofa-Se Sincewecannotknowthedetailedpreparatiｏｎpro‐ cessesofenantiomersof2-ocmolandproline，there stiUremainsthepossibilitythattheenantiomersof theseorganiccompoundsareslightlydifferentmthe qualitywitheachotherうcausingtheenantioselective clystallizationItisquitenecessaryfbrustoknow theprecisepreparatio、ｍｅthodsoftheenantiomersof 2-octanolandproline． Acknowledgments WearegratefUltoＰｒｏｆＮ・AkiyamafbrfiuitfUl (aルーＳｃ:clockwisemjMing （S)-2雪ocQHn⑥lfbr“day魁 ﾕミ付｡_､－１■I｡0 ﾛｲ▲■●--■｡‐●･-。o↑

－－ﾙ1'一

(R>Z-octHnolfbr“鋤３ AA霞……ﾉＬ｡…"′】品…－℃/U>卍－－ＬＡ～争い､-.-.へ～…ｺﾞｰ…－－､ (b川鎚:c･unteMK:!"kwisemju航９（&脚幻cta』nolfbF“鰍 －－－－－４ujULkJL山！ ！ へ－JLJQ-A-会…へｊＡ－＿ ＿■ 仇～■けロハやA姥免ヘムムーか~Q－－－－㎡-.---＝-..---ﾆｰｰﾏ (R)-Z-ocl8mol鹸“daw3 ＡＡＡ－－

EnantioselectivecrystallizationofamorphousSeinthepresenceofchiralorganlcmolecules

● 2９ discussionandadvices． _（2011） 11）NAkiyamaandTOhtani,ＪＺＺｐルイｐｐＬＰ/り八s.,52,105001 （2013)． 12）YProsseLM・Sicha,andEKlieL“比Ｃｅ"/ＡａＷｚ"“Ｓｍ比ルー 〃j""Ｐ伽jcs'',ｐｐｌＯ５,(edEuropeanSelenium-Tbllurium

Committee，PergamonPress，Oxfbrd，London，Edinburgh，

NewYork,Paris,Frankfilrt)，（1964)．

13）Ｍ,J､Gaunt,CCCJohansson,AMcNallybNTVb,Ｄ'Ｗｇ

伽coveひ7ＭJ〕′12,8(2007)．

14）RKaplowJARowc,andBLAverbach,Ｐﾉ！)ﾉ８.比u,168,

1068(1968)．

15）DKCondepudi,RJKaufinan,andNSingh,Sbje"Ｃｅ,250,

975(1990）

16）CVicdma,Ｐ/1)As・比vLe".,94,065504(2005）

17）Ｍ・Gardner,wie伽6jdbxj7o"ｓＵ)､′e酒e",(PengUinBooks

Ltd)(1964） 18）CSWuetaL,Ｐ/1〕』，､比1ﾉ.,105,1413(1957） Refbrences l）EHHenninger,RCBuschert,andLHcaton,よＣ７ｉｅ腕． Ｐ伽.,46,586(1967)． 2）HKrebs,ＺＡ"ｏｌｇＡﾉZgCAe碗.,265,156(1951)． 3）Ｐ・CherinandPUnger,ｈｏｌｇＣﾙe碗.,６，１５８９(1967） 4）PCherinandPUngeMcmO〕ｍＭｂｇ７.,Ｂ28,313(1972)． 5）KTanioka,Ｊ・Yamazaki,KShidara,KTaketoshi,Ｔ､Ｋａ‐ wamura，SIshioka，Ｙ・Takasaki，ＩＥＥＥＥんcか。〃DeWCes Let彪応,EDL-8,9,392(1987） 6）JStuke,`晩ﾉb"ｊ"腕",ｐｐｌ７４,(edR・AZingaroandWC Cooper:VanNostrandRcinhold,NewYork),(1974） 7）nOhtani,NTakayamaKIkcda,ａｎｄＭ､Araki,Ｃ７ｉｅｍ.Ｌｅﾉｰ に西,33,100(2004)．

8）KIkcdaandTOhtanMA"q〕ＡＦＣＯ叩o""ぬ,434-435,275

（2007)． 9）ARSaunders,ＪＰ/ｉ〕』Ｍ沈加.,4,423(1900） １０）NAkiyamaandTOhtanM上Zp.』Ｚ/2ＰＬＰ/i〕As.,50,015002