Dynamic Chi al PPA−AgNP Nanocomposi es: Aligned Sil e
Nanopa icles Deco a ing Helical Polyme s
Manuel Nunez-Ma ínez, Sand a A ias, Emilio Quinoá, Rica do Rigue a, and Félix F ei e*
Ci e This: Chem. Ma e . 2021, 33, 4805−4812
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sıSuppo ing In o ma ion
ABSTRACT: A no el app oach o p epa e s imulus-sensi i e
nanocomposi es is desc ibed, based on a dynamic helical polyme ,
chi al poly(phenylace ylene) (PPA), and sil e nanopa icles. To
p ese e he dynamic helical beha io o PPA wi hin he
nanocomposi e, a weak and adap i e sup amolecula in e ac ion,
such as ha be ween amide g oup−sil e nanopa icle, is used o
link he me al nanopa icle o he polyme . To p epa e he
composi e, we chose PPA as a helical polyme ha bea s an amide
g oup as a monome epea ing uni , poly-(R)-1, which can
coo dina e wi h Ag+ions. The sil e ions ha o m complexes
wi h he pendan g oups a e u he educed, h ough he use o
NaBH4, o AgNPs ha a e s abilized by he amide g oups o PPA.
As a esul , 2.8 nm sil e nanopa icles a e o med and aligned
along he polyme chain wi h a egula 3.1 nm in e pa icle dis ance co esponding o he helical pi ch o he polyme . The weak
amide/AgNP in e ac ions allow PPA o adop ei he Po Mhelical s uc u es on he AgNPs h ough sup amolecula adap i e
mechanisms induced by app op ia e ex e nal s imuli.
■INTRODUCTION
Among many ele an cha ac e is ics, me allic nanopa icles
(MNPs) ha e also a ac ed he a en ion o he scien ific
communi y due o hei op ical p ope ies ela ed o he
p esence o localized su ace plasmon esonance (LSPR)
bands,
1,2
which find applica ions in diffe en fields such as
he anos ics,
3
colo ime ic senso s,
4
d ug deli e y,
5,6
and
su ace Raman sca e ing (SERS)
7−9
among o he s.
One o he main p oblems o MNPs is hei high agg ega ion
endency. To a oid his p oblem, scien is s ha e coa ed he
su ace o he MNPs wi h a la ge a ie y o molecules o
s abilize hem by ei he s e ic o elec os a ic effec s. This
s abiliza ion can be also achie ed using polyme s o mac o-
molecules as coa ing agen s. In such cases, he esul ing hyb id
ma e ials conse e he p ope ies o he MNP, as well as hose
de i ed om he polyme ic coa ing, such as s abili y, solubili y,
and biocompa ibili y.
1,10
In he case o using DNA o p o eins as coa ing agen s o
s abilize he MNP,
1
he biological unc ion o he hyb id
ma e ial is ela ed o he helical s uc u e adop ed by he
mac omolecule. In e es ingly, jus a couple o nanocomposi es
a e epo ed using ha use a non-na u al helical coa ing such
as a syn he ic polyme o a oldame a he han a
biomac omolecule.
11−14
In his sense, de i a iza ion o MNPs
wi h syn he ic dynamic helical polyme s such as poly-
(ace ylene)s (PAs), poly(phenylace ylene)s (PPAs), o poly-
(diphenylace ylene)s (PDPAs) should ep esen a clea
ad an age because hei helical senses (P/M) and/o chain
elonga ions (comp ession/s e ching) a e no fixed as in he
biomac omolecules, and can be uned h ough he ac ion o
ex e nal s imuli.
15−24
Du ing he las yea s, some a emp s ha e been made o
c ea e nanocomposi es based on dynamic helical polyme s and
me al nanopa icles using hiola ed pendan g oups.
11−14
These s udies showed ha he dynamic beha io o he helical
polyme is d ama ically affec ed by he p esence o a hiola ed
monome , whe e he s imuli- esponse p ope ies o he
nanocomposi e a e educed up o 20%. To ci cum en ha
p oblem, a diffe en app oach o link he MNP o PPA mus be
inspec ed.
In his case, we look o weake sup amolecula in e ac ions
be ween PPAs and MNPs, such as hose p esen in PVP−
AgNPs and PVP−AuNPs, whe e poly( inylpy olidone)
(PVP) p o ides he amide g oups equi ed o he s abiliza-
ion.
25−27
Thus, in his wo k, we decided o s abilize AgNPs
wi h dynamic PPA
28−37
bea ing amide g oups in he pendan s
(Scheme 1). In such a case, a sel -adap i e mechanism o
helical in e sion o helical enhancemen is expec ed, whe e a
Recei ed: Ma ch 8, 2021
Re ised: May 4, 2021
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pa o he weak sup amolecula in e ac ions be ween he
amide g oups and he me al nanopa icles a e dis up ed du ing
he helical s uc u al change, sense and/o elonga ion. These
in e ac ions eco e immedia ely a e wa d (Scheme 1), hus
p oducing he same s uc u al changes in he PPA−AgNP
chain ha occu in he isola ed PPA.
■RESULTS AND DISCUSSION
To pe o m hese s udies, wo well-known PPAs we e chosen
as model compounds: poly-(R)-1 ha bea s 4-anilide o (R)-α-
me hoxy-α-phenylace ic acid and poly-(R)-2 ha bea s 4-
anilide o (R)-α-me hoxy ifluo ome hylphenylace ic acid
(Figu e 1). In bo h cases, an amide g oup is p esen in he
monome epea ing uni . These PPAs we e p epa ed acco ding
o p e ious s udies using [Rh(nbd)Cl]2as a ca alys (nbd =
2,5-no bo nadiene) (see he Suppo ing In o ma ion).
18
These wo polyme s, poly-(R)-1and poly-(R)-2, we e
selec ed aking in o accoun hei diffe en dynamic helical
beha io s and he dis inc dono cha ac e o he amide g oup
a he pendan .
Thus, poly-(R)-1is a highly dynamic helical polyme and, in
he absence o ex e nal s imuli, exis s as an axially acemic
polyme , equal popula ions o Pand Mhelices, which can
selec i ely adop a p e e ed Po Mhelici y when di alen o
mono alen me al ions a e added as ex e nal s imuli o a
solu ion o he polyme .
18,38,39
On he o he hand, poly-(R)-2
is also a dynamic helical polyme , whose elonga ion and helical
sense a e affec ed by he dono and pola cha ac e s o he
sol en used o dissol e he polyme .
40
Mo eo e , in he case
o poly-(R)-2, he p esence o a s ong elec on-wi hd awing
g oup, CF3, should deac i a e he dono cha ac e o he
amide. F om hese designs, he e o e, i is possible o e i y he
ole o he amide g oup in he s abiliza ion o he nano-
composi es o PPA−AgNPs.
PPA copolyme s based on poly-(R)-1 ha inco po a e
hiola ed comonome s we e also p epa ed bu hei PPA−
AgNP nanocomposi es did no show, as expec ed, he dynamic
beha io showed by he pa en copolyme s (see he
Suppo ing In o ma ion and e 14).
P epa a ion o Poly-(R)-1-AgNP and Poly-(R)-2-AgNP
Nanocomposi es: Dynamic and Agg ega ion S udies.
Poly-(R)-1-AgNP and poly-(R)-2-AgNP nanocomposi es we e
p epa ed by educ ion wi h NaBH4o wo diffe en solu ions
con aining poly-(R)-1/Ag+and poly-(R)-2/Ag+complexes as
desc ibed below.
As will be seen h oughou his discussion, he p esence o
mono- and di alen me al ca ions (Mn+=Li
+,Na
+,Ag
+, and
Ba2+) also plays a undamen al ole when desc ibing hese
nanocomposi es. The e o e, om now on, we will use names
o he o ms “poly-(R)-1(o 2)-AgNPs/Mn+”when hese
ca ions a e p esen and “poly-(R)-1(o 2)-AgNPs”when hey
a e no .
Poly-(R)-1-AgNPs/Na+Nanocomposi e. Ame hanolic
solu ion (0.5 equi ) o AgClO4(10 mg·mL−1) was added o
a chlo o o m solu ion o poly-(R)-1(0.3 mg·mL−1).
CD s udies showed a chi al enhancemen o he axially
acemic poly-(R)-1(CD380 = 0) owa d an Mhelical sense
Scheme 1. P epa a ion o Hyb id PPA−MNPs Using Sup amolecula Amide/PPA−MNP In e ac ions
Figu e 1. Chemical s uc u es o monome s and polyme s used in his
wo k.
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(CD380 < 0) due o he complexa ion o poly-(R)-1wi h Ag+ o
o m he poly-(R)-1/Ag+complex in a 1.0/0.5 mol/mol a io
(Figu e 2a,b).
18
Nex , 1 equi o he educing agen (NaBH4,1
mg·mL−1, MeOH) was added o he solu ion mix u e. CD
s udies showed an M(CD380 <0) oPhelical in e sion (CD380
>0)(Figu e 2a,b). Simul aneously, he appea ance o an LSPR
band in he UV− is spec um a ound 404 nm was obse ed,
indica ing he o ma ion o sphe ical AgNPs (Figu e 2c).
Mo eo e , Fou ie ans o m in a ed (FT-IR) and 1H NMR
s udies confi med he o ma ion o he poly-(R)-1-AgNPs/Na+
hyb id ma e ial (see he Suppo ing In o ma ion). This
nanocomposi e showed li le s abili y in solu ion o e ime,
o ming agg ega es ha we e de ec ed by he deple ion o he
LSPR band (see he Suppo ing In o ma ion, Figu e S23). To
p e en he agg ega ion o he poly-(R)-1-AgNPs/Na+nano-
composi e and imp o e i s s abili y in he solu ion, 1-
dodecane hiol was used as a cop o ec ing agen .
Thus, 0.2 equi o 1-dodecane hiol was added o a
dispe sion o poly-(R)-1-AgNPs/Na+immedia ely a e
addi ion o he educing agen . In hese condi ions, he poly-
(R)-1-AgNPs/Na+/dodecane hiol nanocomposi e shows an
LSPR band a ca. 412 nm, whose in ensi y does no a y
wi h ime, he e o e confi ming he p esence o a s able poly-
(R)-1-AgNPs/Na+hyb id ma e ial (Figu e 2c).
The mo phology o he poly-(R)-1-AgNPs/Na+/dodecane-
hiol nanocomposi e was s udied by elec on mic oscopy
s udies. To his end, a solu ion o he poly-(R)-1-AgNPs/Na+/
dodecane hiol nanocomposi e was d op-cas on o a silicon
wa e and a ca bon g id o scanning (SEM) and ansmission
elec on mic oscopy (TEM) s udies, espec i ely. The images
ob ained om hese s udies showed he p esence o small and
egula ly dis ibu ed AgNP nanosphe es (2.8 ±0.6 nm), which
a e andomly dis ibu ed along he helical polyme pe iphe y
and sepa a ed ca. 3.1 nm, a alue ha is coinciden wi h he
helical pi ch o poly-(R)-1(Figu e 2d,e and he Suppo ing
In o ma ion, Figu es S21 and S25).
Hence, he helical PPA ac s as a empla e by fixing he Ag+
ions on he amide g oups o he polyme . Fu he educ ion o
hese sil e ions o Ag°leads o he o ma ion o AgNPs
egula ly aligned on he polyme .
An in e es ing effec obse ed du ing he o ma ion o he
poly-(R)-1-AgNPs/Na+nanocomposi e ha dese es o be
explained is he helical in e sion om M o Pp oduced in
poly-(R)-1when Ag+in he poly-(R)-1/Ag+complex is
educed o Ag°using NaBH4.
F om p e ious s udies, i is known ha poly-(R)-1beha es
as axially acemic in CHCl3, a mix u e o Pand Mhelices in
equal popula ions. The addi ion o pe chlo a e sal s o
mono alen me al ions such as Li+,Na
+,o Ag
+ o a
chlo o o m solu ion o poly-(R)-1leads o he o ma ion o
a poly-(R)-1/M+complex, whe e he me al ion coo dina es he
ca bonyl o he anilide g oup and es ablishes a ca ion−π
in e ac ion wi h he a yl ing o he pendan . The s eng h o
he ca ion−πin e ac ions depends on he na u e o he me al
ca ion. Fo ins ance, only a ew examples o Na+−πcomplexes
ha e been published, being known ha ca ion−πin e ac ions
wi h Na+a e weake han wi h Li+.
41−45
As a esul , an an ipe iplana con o ma ion o he (O−)C
C(O) bond is fixed in he pendan (Figu e 2a), which
induces an excess o Mhelical sense in he PPA.
18,38
Ne e heless, in he special case o he poly-(R)-1/Na+
complex, i was ound ha he addi ion o a dono sol en
such as MeOH dis up s he ca ion−πin e ac ion and p omo es
he o ma ion o a new chela e be ween he Na+ion and he
Figu e 2. (a) Schema ic ep esen a ion o he Mhelix induc ion o poly-(R)-1by complexa ion wi h Ag+ ollowed by educ ion wi h NaBH4 o
o m he desi ed poly-(R)-1-AgNPs/Na+ ollowed by u he s abiliza ion wi h dodecane hiol. (b) CD spec a o poly-(R)-1/Ag+, poly-(R)-1-
AgNPs/Na+, and poly-(R)-1-AgNPs/Na+/dodecane hiol. (c) UV− is spec a o poly-(R)-1/Ag+, poly-(R)-1-AgNPs/Na+, and poly-(R)-1-AgNPs/
Na+/dodecane hiol. (d) Molecula model o poly-(R)-1-AgNPs. (e) T ansmission elec on mic oscopy (TEM) images o poly-(R)-1-AgNPs/Na+/
dodecane hiol.
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ca bonyl and me hoxy g oups o he pendan moie y (Figu e
3).
41
As a consequence, a synpe iplana con o ma ion o he
(O−)CC(O) bond is s abilized in he pendan , inducing
aPhelix in he PPA.
41
The e o e, an M o Phelix in e sion
occu s in he poly-(R)-1/Na+complex h ough ac i a ion/
deac i a ion o he ca ion−πin e ac ion.
41
This in o ma ion sugges s ha he helix in e sion ha
occu s when poly-(R)-1/Ag+is ans o med in o poly-(R)-1-
AgNPs/Na+may be ela ed o he p esence o Na+ions
in oduced wi h he NaBH4 educing agen , poly-(R)-1-
AgNPs/Na+, and no o he AgNPs hemsel es. Hence, se e al
expe imen s we e ca ied ou o confi m his hypo hesis.
Use o Me al Sca enge Resins. The poly-(R)-1-AgNPs/
Na+/dodecane hiol nanocomposi e was dispe sed in chlo o-
o m (0.3 mg·mL−1), posi i e CD, Phelix. The addi ion o a
me al sca enge esin (Quad apu e IDA) p oduces an axially
acemic helix, simila o ha obse ed o poly-(R)-1when
dissol ed in chlo o o m in he absence o me al ions (Figu e
3b). UV− is s udies o he poly-(R)-1-AgNPs/Na+/dodeca-
ne hiol nanocomposi e a e ea men wi h he me al
sca enge esin show he LSPR band o sphe ical AgNPs,
indica ing ha he nanocomposi e emains unal e ed be o e
and a e he addi ion o he sca enge (Figu e 3c).
This expe imen indica es ha he Phelical sense induced in
he poly-(R)-1-AgNPs/Na+/dodecane hiol nanocomposi e is
due o he p esence o Na+ions om NaBH4, which o m
complexes wi h he hyb id ma e ial, poly-(R)-1-AgNPs/Na+/
dodecane hiol. The addi ion o a me al sca enge esin
emo es he Na+ions om he dispe sed nanocomposi e,
poly-(R)-1-AgNPs/dodecane hiol hyb id ma e ial, which e-
co e s i s highly dynamic beha io (equal mix u e o Pand M
helices) (Figu e 3a).
LiBH4as a Reducing Agen . F om p e ious s udies, i is
known ha he poly-(R)-1/Na+complex can selec i ely adop
an Mo Phelical sense by ac i a ion/deac i a ion o ca ion−π
in e ac ions. In he case o he poly-(R)-1/Li+complex,
dis up ion o he ca ion−πin e ac ion is no possible, and as a
esul , only an Mhelix can be induced in ha complex (see he
Suppo ing In o ma ion, Figu e S27).
41
Thus, when LiBH4is used as a educing agen o p oduce
he poly-(R)-1-AgNPs/Li+/dodecane hiol nanocomposi e, an
Mhelix is induced in poly-(R)-1, opposi e o he esul ing P
helix when NaBH4is used as educe , poly-(R)-1-AgNPs/Na+/
dodecane hiol nanocomposi e, (see he Suppo ing In o ma-
ion, Figu e S27). The subsequen addi ion o a me al
sca enge esin o ap Li+ions p oduces, as expec ed, he
o ma ion o a mac oscopically acemic poly-(R)-1-AgNPs
nanocomposi e. This ac clea ly indica es ha he Pand M
helical senses induced in he poly-(R)-1-AgNPs/Li+/dodeca-
ne hiol hyb id ma e ial a e due o he Na+and Li+ions p esen
in NaBH4and LiBH4and no due o he p esence o AgNPs.
Dynamic Beha io o Poly-(R)-1-AgNPs/Dodecane hiol.
The dynamic beha io o axially acemic poly-(R)-1-AgNPs/
dodecane hiol was s udied by adding 0.2 equi o AgClO4and
Ba(ClO4)2as sou ces o mono alen and di alen me al ions,
[AgClO4and Ba(ClO4)2] = 10 mg·mL−1, MeOH. In bo h
cases, la ge chi al enhancemen s we e obse ed owa d M,
poly-(R)-1-AgNPs/Ag+/dodecane hiol, and P,poly-(R)-1-
AgNPs/Ba2+/dodecane hiol, helices, simila o hose ob ained
o poly-(R)-1/Ag+and poly-(R)-1/Ba2+, espec i ely (Figu e
4b and he Suppo ing In o ma ion, Figu es S32 and S33).
Figu e 3. (a) Schema ic illus a ion o he ole o Na+in he o ma ion o poly-(R)-1-AgNPs/Na+nanocomposi es. (b) CD s udies o poly-(R)-1-
AgNPs/Na+p epa ed using NaBH4be o e and a e ea men wi h a me al sca enge esin and (c) UV− is s udies o a poly-(R)-1-AgNPs/Na+
p epa ed using NaBH4be o e and a e ea men wi h a me al sca enge esin.
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These esul s indica e ha a sup amolecula in e ac ion
be ween he me al nanopa icle and he polyme does no
affec he dynamic helical beha io o he polyme . They also
e eal ha poly-(R)-1-AgNPs/dodecane hiol ollows a sel -
adap i e mechanism, in which AgNPs lodge a diffe en
loca ions in PPA in esponse o he helical s uc u al changes
ha he polyme unde goes.
Agg ega ion Con ol o Poly-(R)-1-AgNPs/Mn+/Dodeca-
ne hiol Complexes. The abili y o poly-(R)-1/Mn+/dodeca-
ne hiol complexes o o m nanos uc u es such as nano-
sphe es
18,38
was es ed in he nanocomposi e/Mn+complex,
poly-(R)-1-AgNPs/Mn+,M
n+=Ag
+,Ba
2+ (Figu e 4a). Thus,
he poly-(R)-1-AgNPs/dodecane hiol nanocomposi e was
dispe sed in chlo o o m (0.3 mg·mL−1) and 0.2 equi o
AgClO4was added o o m he poly-(R)-1-AgNPs/Ag+/
dodecane hiol complex in a 1.0/0.2 mol/mol a io. DLS and
SEM show he o ma ion o s able and low polydispe sed
nanosphe es (size: 163 ±36 nm) (Figu e 4c,d), which a e
made o helical s uc u es wi h an Mhelical sense excess
(CD380 < 0). In e es ingly, i is possible o dis inguish he
AgNP nanopa icles embedded in he nanosphe es om he
SEM images (Figu e 4d).
Simila expe imen s we e ca ied o poly-(R)-1-AgNPs/
Ba2+/dodecane hiol in a 1.0/0.2 mol/mol a io ha led o he
o ma ion o low polydispe sed nanosphe es (size: 61 ±21
nm) wi h opposi e mac oscopic chi ali y (Phelices, CD380 >0)
(see Figu e 4c,d and he Suppo ing In o ma ion, Figu es S32
and S33).
Poly-(R)-2-AgNPs/Dodecane hiol Nanocomposi e. Poly-
(R)-2-AgNPs/dodecane hiol was p epa ed using poly-(R)-2
as a empla e and eso ing o he same me hodology
de eloped o p epa e he poly-(R)-1-AgNPs/dodecane hiol
nanocomposi e. This polyme adop ed an Mhelix (CD380 <0)
once was dissol ed in chlo o o m (Figu e 5a−c).
40
Ul e io
addi ion o a me hanolic solu ion o 0.5 equi o AgClO4(10
mg·mL−1) gene a ed he poly-(R)-2/Ag+complex by coo di-
na ion o he Ag+ions o he ca bonyl g oup o he pendan ,
al hough no helical changes we e obse ed in poly-(R)-2
(CD380 <0)(Figu e 5a−c). Nex , he o ma ion o he poly-
(R)-2-AgNP/dodecane hiol nanocomposi e was achie ed by
adding NaBH4as a educing agen (see he Suppo ing
In o ma ion o a ull s uc u al cha ac e iza ion). TEM s udies
o he poly-(R)-2-AgNP/dodecane hiol nanocomposi e in-
dica ed he ole o he amide g oup in he s abiliza ion o
AgNPs. In his case, he p esence o a s ong elec on-
wi hd awing g oup (−CF3) in poly-(R)-2diminishes he
dono capaci y o he amide unc ion. This ac has a g ea
effec on he s abiliza ion o AgNPs, which leads o he
o ma ion o i egula , polydispe sed, and andomly dis ibu ed
AgNPs wi hin he poly-(R)-2-AgNP/dodecane hiol nano-
composi e (Figu e 5d).
■CONCLUSIONS
A no el app oach o ob ain PPA−AgNP nanocomposi es
wi hou al e ing he dynamic beha io o he pa en polyme is
desc ibed.
Weak amide−AgNP sup amolecula in e ac ions a e used o
p epa e chi al dynamic nanocomposi es. To pe o m hese
s udies, poly-(R)-1, bea ing 4-anilide o (R)-α-me hoxy-α-
phenylace ic acid was chosen as a p o ec ing agen . Fi s , a
poly-(R)-1/Ag+complex is o med in a 1.0/0.5 mol/mol a io,
which is u he educed o he poly-(R)-1/AgNPs/Na+/
dodecane hiol nanocomposi e using NaBH4as a educing
agen . TEM s udies o he nanocomposi e show ha he
AgNPs a e egula ly dis ibu ed along he polyme chain. Poly-
(R)-1ac s as a empla e by placing he AgNPs a fixed
Figu e 4. (a) Chi al enhancemen o poly-(R)-1-AgNPs nanocomposi es by addi ion o 0.2 equi o Ag+and Ba2+. (b) CD s udies o poly-(R)-1-
AgNPs/Ag+/dodecane hiol and poly-(R)-1-AgNPs/Ba2+/dodecane hiol complexes. (c) Dynamic ligh sca e ing (DLS) s udies o poly-(R)-1-
AgNPs/Ag+/dodecane hiol and poly-(R)-1-AgNPs/Ba2+/dodecane hiol complexes. (d) SEM images o poly-(R)-1-AgNPs/Ag+/dodecane hiol and
poly-(R)-1-AgNPs/Ba2+/dodecane hiol nanosphe es.
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dis ances o 3.1 nm, which co esponds o he helical pi ch o
poly-(R)-1. S imuli- esponsi e s udies show ha he poly-(R)-
1/AgNPs/dodecane hiol nanocomposi e esponds o mono-
alen and di alen me al ions jus like he pa en polyme ,
poly-(R)-1, does. Hence, a Phelix is induced by mono alen
me al ions, while an Mhelix is fixed when di alen me al ions
a e added o a dispe sion o he hyb id ma e ial. Mo eo e ,
du ing hese s udies, he abili y o he poly-(R)-1/AgNPs/
Mn+/dodecane hiol nanocomposi e o o m o he nanos uc-
u es such as nanosphe es was also demons a ed.
■EXPERIMENTAL SECTION
Chemicals. Comme cially a ailable chemicals we e used as
deli e ed. Sol en s we e pu chased o eagen g ade and dis illed i
necessa y. Anhyd ous sol en s we e ei he pu chased as ul ad y
sol en s om Ac os O ganics o ecei ed om a sol en pu ifica ion
sys em. Fo he coupling and polyme iza ion eac ions, d y
e ahyd o u an (THF) was ob ained om an MBRAUN SPS 800
sol en pu ifica ion sys em. Wa e was pu ified by a Millipo e wa e
pu ifica ion sys em. Coupling eagen s (2-(7-aza-1H-benzo iazole-1-
yl)-1,1,3,3- e ame hylu onium hexafluo ophospha e) (HATU), 1-
hyd oxy-7-azabenzo iazole (HOAT), 4- e hynylbenzoic acid, and 4-
e hynylaniline we e pu chased om AnaSpec Inc. (R)-α-Me hox-
yphenylace ic acid, (R)-α-me hoxy-α- ifluo ophenylace ic acid, oxalyl
cho ide, hodium no bo nadiene chlo ide dime {[Rh(nbd)Cl]2},
diisop opyl ie hylamine (DIEA), ie hylamine (TEA, 99%), dodec-
ane hiol, sodium bo ohyd ide (NaBH4), sil e pe chlo a e (AgClO4),
and ba ium pe chlo a e [Ba(ClO4)2] we e pu chased om Sigma-
Ald ich.
Ins umen a ion and Cha ac e iza ion. NMR expe imen s
we e ca ied ou in a Va ian Ino a 300 (300 MHz esonance 1H).
Size exclusion ch oma og aphy s udies we e pe o med on an Alliance
2695 HPLC (Wa e s) liquid ch oma og aphy sys em equipped wi h a
UV 2489 de ec o (Wa e s). The samples we e elu ed by h ee
Phenogel columns connec ed o each o he wi h s a iona y phases o
103,10
4, and 105Å and packed wi h a solid suppo o a c oss-linked
s y ene and p-di inylbenzene copolyme . CD and UV measu emen s
we e pe o med in a Jasco-720 spec opola ime e and a Jasco-730
spec opho ome e , espec i ely, a a nanocomposi e concen a ion o
0.3 mg·mL−1. FT-IR measu emen s we e ca ied ou on a B uke IFS-
66 . DLS s udies we e pe o med on a Nano-ZS 90 (Mal e n)
equipped wi h a He−Ne lase (l= 633 nm) unde a sca e ing angle
o 173°. The samples we e main ained a he designed empe a u e
o 5 min be o e es ing. DLS measu emen s we e ca ied ou in all
cases a 0.3 mg·mL−1. SEM samples we e pe o med on a LEO-435VP
elec on mic oscope. SEM measu emen s we e pe o med on a LEO-
435VP elec on mic oscope equipped wi h an ene gy-dispe si e X- ay
(EDX) spec ome e . TEM measu emen s we e pe o med on a JEOL
JEM 2010 and 200 kV as a ol age. To s udy he nanocomposi e o
he nanosphe es, he same p o ocol was used. A dispe sion o he
nanocomposi e o he nanosphe es a a concen a ion o 0.3 mg·mL−1
was d op-cas ed on o a silicon wa e chip and allowed o d y a o
12 h o SEM s udies, while in he case o TEM s udies, he dispe sed
ma e ials we e d op-cas ed on o a ca bon chip and allowed o d y a
o 12.h.
■ASSOCIATED CONTENT
*
sıSuppo ing In o ma ion
The Suppo ing In o ma ion is a ailable ee o cha ge a
h ps://pubs.acs.o g/doi/10.1021/acs.chemma e .1c00805.
Ma e ials and me hods; syn hesis o monome M1;
syn hesis o monome M2; syn hesis o polyme s poly-
(R)-1 and poly-(R)-2; CD and UV− is s udies o poly-
(R)-2 wi h mono alen and di alen me al ions; gene al
p ocedu e o syn hesis o poly-1-AgNPs and poly-(R)-2-
AgNPs; 1H NMR o poly-1-AgNPs; FT-IR s udies o
poly-(R)-1-AgNPs and poly-(R)-2-AgNPs; syn hesis o
poly-1-AgNPs in diffe en sol en s; CD and UV− is
s udies o poly-1-AgNPs/me al ion in e ac ions; mic os-
copy s udies o poly-1-AgNPs: SEM and TEM images;
he s abili y o poly-(R)-1-AgNPs wi h ime; s abiliza ion
o poly-(R)-1-AgNPs using dodecane hiol; mic oscopy
s udies o poly-2-AgNPs: TEM images; o ma ion o
poly-(R)-1-AgNPs using LiBH4; he effec o NaBH4in
he helical sense o poly-(R)-1-AgNPs; he ole o Na+
ca ions in he helici y o poly-(R)-1-AgNPs, expe imen s
wi h me al sca enge esins; o ma ion o chi al
nanosphe es using poly-(R)-1-AgNPs and mono alen
and di alen me al ions; con ol s udies: “enan iome
compa ison”; con ol s udies: “ hiol linkage”poly-[(R)-
1 -co-31− ]; chi al enhancemen and e e sibili y o he
p ocess wi h esin me al sca enge s in he p esence o
sil e nanopa icles; and e e ences (PDF)
■AUTHOR INFORMATION
Co esponding Au ho
Félix F ei e −Cen o Singula de in es igación en Química
Biolóxica e Ma e iais Molecula es (CiQUS) and
Depa amen o de Química O gánica, Uni e sidade de
San iago de Compos ela, E-15782 San iago de Compos ela,
Figu e 5. (a) Schema ic illus a ion o poly-(R)-2-AgNPs/dodeca-
ne hiol nanocomposi e o ma ion. (b) CD s udies o poly-(R)-2, poly-
(R)-2/Ag+(1.0/0.5 mol/mol) and poly-(R)-2-AgNPs. (c) UV− is
s udies o poly-(R)-2, poly-(R)-2/Ag+(1.0/0.5 mol/mol) and poly-
(R)-2-AgNPs. (d) TEM images o poly-(R)-2-AgNPs/dodecane hiol.
Chemis y o Ma e ials pubs.acs.o g/cm A icle
h ps://doi.o g/10.1021/acs.chemma e .1c00805
Chem. Ma e . 2021, 33, 4805−4812
4810
Spain; o cid.o g/0000-0002-2672-5830;
Email: [email p o ec ed]
Au ho s
Manuel Nunez-Ma ínez −Cen o Singula de in es igación
en Química Biolóxica e Ma e iais Molecula es (CiQUS) and
Depa amen o de Química O gánica, Uni e sidade de
San iago de Compos ela, E-15782 San iago de Compos ela,
Spain; o cid.o g/0000-0003-2715-0722
Sand a A ias −Cen o Singula de in es igación en Química
Biolóxica e Ma e iais Molecula es (CiQUS) and
Depa amen o de Química O gánica, Uni e sidade de
San iago de Compos ela, E-15782 San iago de Compos ela,
Spain
Emilio Quinoá−Cen o Singula de in es igación en Química
Biolóxica e Ma e iais Molecula es (CiQUS) and
Depa amen o de Química O gánica, Uni e sidade de
San iago de Compos ela, E-15782 San iago de Compos ela,
Spain; o cid.o g/0000-0003-3019-3408
Rica do Rigue a −Cen o Singula de in es igación en
Química Biolóxica e Ma e iais Molecula es (CiQUS) and
Depa amen o de Química O gánica, Uni e sidade de
San iago de Compos ela, E-15782 San iago de Compos ela,
Spain
Comple e con ac in o ma ion is a ailable a :
h ps://pubs.acs.o g/10.1021/acs.chemma e .1c00805
No es
The au ho s decla e no compe ing financial in e es .
■ACKNOWLEDGMENTS
The au ho s hank Se icio de Mic oscopía Elec ónica
(RIAIDT, USC). Financial suppo om AEI (PID2019-
109733GB-I00), Xun a de Galicia ED431C 2018/30, Cen o
Singula de In es igación de Galicia ac edi ación 2019−2022,
ED431G 2019/03, Beca Leona do a In es igado es y
C eado es Cul u ales 2020 de la Fundación BBVA, and he
Eu opean Regional De elopmen Fund (ERDF) is g a e ully
acknowledged. N.-M. hanks MICINN o a FPI con ac
(BES-2016-078107).
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