Page 3 of 12
J o& u' (r n) a* (l oꢀ +f ,Mꢀ -a ,t e. ꢀ r)i a+ l/ s0 C* .hꢀ 1e m) 2i 3s t4 -r y* A
DOI: 10.1039/D0TA00212G
ꢀB.6('13ꢀ."ꢀC1$!()13%ꢀ0*!D)%$(7ꢀAꢀ
ꢀA5@?0ꢁ&
/
/
>
:2,':*4*ꢀ ,-':ꢀ 8)>>(-*ꢀ 0-+(2ꢀ 8438ꢀ .(1>(2).02(Cꢀ !8(ꢀ
(>2(*(-.).46(ꢀ.845U-(**ꢀ,Oꢀ%dPDC]Pa77ꢀ4*ꢀ1()*02(+ꢀ.,ꢀH(ꢀ
2,0-+ꢀDD7ꢀ-1ꢀV_4302(ꢀBHZCꢀ!8(ꢀG!%dꢀ41)3(ꢀV_4302(ꢀB5ZꢀO02.8(2ꢀ
,-O421*ꢀ.8(ꢀ*8((.P'4U(ꢀ*.205.02(ꢀ,Oꢀ%dPDC]Pa77ꢀ)-+ꢀ('(1(-.)'ꢀ
1)>>4-3*ꢀ*033(*.ꢀ.8(ꢀM=ꢀ@ꢀ)-+ꢀ#ꢀ)2(ꢀ8,1,3(-,0*':ꢀ+4*>(2*(+ꢀ
82,038,0.ꢀ.8(ꢀ5)2H,-ꢀ-)-,O')U(*Cꢀ!8(ꢀ1(*,>,2,0*ꢀ*.205.02(ꢀ
B77ꢀ13ꢀ5)2H,-ꢀ5).)':*.ꢀV)>>)2(-.ꢀH(+ꢀ6,'01(ꢀ)55,0-.(+ꢀ.,ꢀ 4*ꢀ)'*,ꢀ,H*(26(+ꢀH:ꢀ.8(ꢀG!%dꢀV_4302(ꢀB+ZCꢀ!8(ꢀQ !%dꢀ41)3(*ꢀ,Oꢀ
,
-. ( 0 1 . ( ,-0
3, $ '--- 456789ꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀV;Zꢀꢀ
3,$ '-:; 456789ꢀꢀꢀꢀꢀꢀꢀꢀꢀVDZ
3,$ '<=/ 456789ꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀVYZꢀ
-
-
2
2
2
/
)
.2
( 0- 1.0-
2
5
<
,
-. ( 0 1.0- ( ,-0
-
-
.
D
)
2,0-+ꢀaꢀ51 ZꢀT)*ꢀ>0.ꢀ4-ꢀ.8(ꢀ14++'(ꢀ>)2.ꢀ,Oꢀ.8(ꢀ.0H0')2ꢀK0)2.[ꢀ -)-,O')U(*ꢀ4-ꢀ_4302(ꢀB(=ꢀOꢀ5'()2':ꢀ*8,T*ꢀ)H0-+)-.ꢀ(+3(ꢀ*4.(*ꢀ)-+ꢀ
()5.,2ꢀV"C?CꢀB7ꢀ11ZCꢀ!8(ꢀO02-)5(ꢀ.(1>(2).02(ꢀ,Oꢀ2()5.,2ꢀT)*ꢀ .:>45)'ꢀ4-.(2'):(2ꢀ*>)54-3ꢀ,OꢀDC]ꢀsꢀT8458ꢀ5)-ꢀH(ꢀ)*524H(+ꢀ.,ꢀ.8(ꢀ
,-.2,''(+ꢀ)-+ꢀ1,-4.,2(+ꢀH:ꢀ.T,ꢀiP.:>(ꢀ.8(21,5,0>'(*ꢀV4-ꢀ.8(ꢀ V77;Zꢀ52:*.)'ꢀ>')-(ꢀ,Oꢀ32)>84.(Cꢀ
4++'(ꢀ>)2.ꢀ,Oꢀ.8(ꢀO02-)5(ZCꢀ!8(ꢀ2()5.)-.*ꢀ5,-.)4-ꢀ5(2.)4-ꢀ
!8(ꢀ.(<.02)'ꢀ>2,>(2.4(*ꢀ,OꢀMP+,>(+ꢀ5)2H,-ꢀ-)-,O')U(*ꢀ)2(ꢀ
1,0-.ꢀ,OꢀQ GꢀV(C3CꢀBC7ꢀ6,'C^Z=ꢀ@ ꢀV(C3CꢀBC]=ꢀ;C]ꢀ6,'C^Z=ꢀQ @ꢀV(C3Cꢀ 5,-+05.(+ꢀ.82,038ꢀM ꢀ>8:*4*,2>.4,-ꢀ(<>(241(-.*ꢀV_4302(ꢀ;ꢀ)-+ꢀ
PꢀD7ꢀ6,'C^Z=ꢀ)-+ꢀH)')-5(+ꢀT4.8ꢀQ(ꢀV.,.)'ꢀO',Tꢀ2).(ꢀB77ꢀ1$F14-=ꢀ !)H'(ꢀ GBZCꢀ !8(ꢀ *02O)5(ꢀ )2()*ꢀ ,Oꢀ .8(*(ꢀ MP+,>(+ꢀ 5)2H,-ꢀ
2
5
1
)
7
;
;
;
;
;
PB
5
,-.2,''(+ꢀH:ꢀ1)**ꢀO',Tꢀ5,-.2,''(2ZCꢀ!8(ꢀ*.()1ꢀT)*ꢀO(+ꢀ.,ꢀ.8(ꢀ -)-,O')U(*ꢀ)2(ꢀ4-ꢀ)ꢀH2,)+ꢀ2)-3(ꢀ,Oꢀb7]PD]D7ꢀ1 3 ꢀ)-+ꢀ.,.)'ꢀ
D
PB
2
()5.)-.*ꢀH:ꢀH0HH'4-3ꢀQ(ꢀO',Tꢀ.82,038ꢀ)ꢀ+(4,-4[(+ꢀT).(2ꢀ >,2(ꢀ6,'01(*ꢀ)2(ꢀ6)24(+ꢀO2,1ꢀ7C;bꢀ.,ꢀBCEEꢀ51 3 ꢀV!)H'(ꢀGBZCꢀ!8(ꢀ
,-.)4-(+ꢀ '4K04+ꢀ *).02).,2ꢀ .8).ꢀ 1)4-.)4-(+ꢀ ).ꢀ 5(2.)4-ꢀ *)1>'(*ꢀ(<84H4.ꢀ.:>45)'ꢀ1452,>,2(*ꢀ)-+ꢀ1(*,>,2,0*ꢀO4-3(2>24-.ꢀ
(1>(2).02(Cꢀ_,2ꢀ.8(ꢀ5,-.2,'ꢀ(<>(241(-.=ꢀ.8(ꢀT(438.ꢀ8,02':ꢀ )55,2+4-3ꢀ .,ꢀ .8(ꢀ -4.2,3(-ꢀ )+*,2>.4,-P+(*,2>.4,-ꢀ 4*,.8(21*ꢀ
5
.
PB
*
>)5(ꢀ6(',54.:ꢀVpQG`ZꢀT)*ꢀ*(..'(+ꢀ).ꢀ2)-3(ꢀ,Oꢀ7CbꢀPꢀBC;ꢀ8 =ꢀ.8(ꢀ V_4302(ꢀ;)ꢀ)-+ꢀ5ZCꢀA''ꢀ.8(ꢀ*)1>'(*ꢀ>2(*(-.ꢀ.8(ꢀ*414')2ꢀ>,2(ꢀ
P.,PQ Gꢀ1,')2ꢀ2).4,ꢀT)*ꢀ6)24(+ꢀO2,1ꢀBC]ꢀ.,ꢀ;C]=ꢀ)-+ꢀ.8(ꢀ*.()1ꢀ *.205.02(ꢀ)*ꢀ*8,T-ꢀ4-ꢀ.8(ꢀ>,2(ꢀ*4[(ꢀ+4*.24H0.4,-ꢀ5026(ꢀV_4302(ꢀ;Hꢀ
,-5(-.2).4,-ꢀT)*ꢀ*(..'(+ꢀ).ꢀ.8(ꢀ2)-3(ꢀ,Oꢀ7ꢀPꢀD7ꢀ6,'C^Cꢀ!,ꢀ*.0+:ꢀ )-+ꢀ+ZCꢀG058ꢀ84(2)25845)'':ꢀ>,2,0*ꢀ*.205.02(ꢀV1452,>,2(*ꢀ)-+ꢀ
8(ꢀ.,'(2)-5(ꢀ,OꢀMP+,>(+ꢀ5)2H,-ꢀ-)-,O')U(*ꢀO,2ꢀ41>024.:ꢀ3)*(*=ꢀ 1(*,>,2,0*ꢀT8458ꢀ5(-.2(+ꢀ).ꢀ)2,0-+ꢀ;Paꢀ-1Zꢀ)2(ꢀ>2,H)H':ꢀ
dPDC]Pa77ꢀ5).)':*.ꢀT)*ꢀ.)U(-ꢀ.,ꢀ(<>',2(ꢀ.8(ꢀ(OO(5.ꢀ,Oꢀ#@ ꢀ)-+ꢀ 52().(+ꢀ H:ꢀ .8(ꢀ )5.46).4,-ꢀ H:ꢀ i@Qꢀ )-+ꢀ .8(ꢀ +(5,1>,*(+ꢀ
8(ꢀ5).)':*.ꢀ)1,0-.ꢀT)*ꢀX]ꢀ13Cꢀ!8(ꢀ2()5.,2ꢀT)*ꢀO(+ꢀT4.8ꢀ7=ꢀ;C]ꢀ 1,'(50'(*ꢀVMQ =ꢀQ @=ꢀ#@ =ꢀM@ ꢀ)-+ꢀM@ꢀ(.5CZꢀO2,1ꢀ.8(ꢀ5)2H,-ꢀ
@
;
;
5
.
%
;
.
D
;
;
;
Y;
,
;
2ꢀ]7ꢀ6,'C^ꢀ#@ ꢀ4-ꢀ2()5.)-.ꢀVB77ꢀ1$F14-Z=ꢀ,.8(2ꢀ2()5.)-.*ꢀT(2(ꢀ )-+ꢀ-4.2,3(-ꢀ>2(502*,2*ꢀ+024-3ꢀ>:2,':*4*ꢀ>2,5(**C ꢀ".ꢀ4*ꢀ5'()2ꢀ
)
++(+ꢀ)*ꢀ.8).ꢀO,2ꢀ-,21)'ꢀ2()5.4,-ꢀ5,-+4.4,-*Cꢀ!8(ꢀA34'(-.ꢀXaE7jꢀ .8).ꢀ.8(ꢀ>2(>)2).4,-ꢀ1(.8,+*ꢀ4-ꢀ.84*ꢀT,2Uꢀ8)6(ꢀ)ꢀ-(3'434H'(ꢀ
)*ꢀ582,1).,32)>8ꢀVL#Zꢀ5,0>'(+ꢀT4.8ꢀ)ꢀ.8(21)'ꢀ5).8)2,1(.(2ꢀ (OO(5.ꢀ,-ꢀ.8(ꢀ>,2(ꢀ*.205.02(ꢀ,Oꢀ)*P*:-.8(*4[(+ꢀMP+,>(+ꢀ5)2H,-ꢀ
3
+
(.(5.,2ꢀV!#?Zꢀ4*ꢀ0*(+ꢀ.,ꢀ+(.(5.ꢀ.8(ꢀ,0.'(.ꢀ3)*(*ꢀV(C3Cꢀ@
-+ꢀG@ ZCꢀ
8(ꢀ5,-6(2*4,-ꢀ,OꢀQ
0'O02ꢀO,21).4,-ꢀ2).(ꢀ,OꢀqGGAꢀ)-+ꢀq5).Cꢀ-,21)'4[(+ꢀH:ꢀ*02O)5(ꢀ)2()ꢀ 2()5.4,-ꢀ,-ꢀ.8(ꢀ(<>,*(+ꢀ)5.46(ꢀ*4.(*ꢀ5,0'+ꢀH(ꢀ)584(6(+ꢀ4-ꢀ')23(ꢀ
-+ꢀ1)**ꢀ,Oꢀ.8(ꢀMP+,>(+ꢀ5)2H,-ꢀ-)-,O')U(*ꢀT(2(ꢀ5)'50').(+ꢀH:ꢀ (<.(-.ꢀ)*ꢀ.845U-(**ꢀ,Oꢀ)*P*:-.8(*4[(+ꢀ-)-,O')U(*ꢀ)2(ꢀ)2,0-+ꢀDD7ꢀ
;
=ꢀQ
;
Gꢀ -)-,O')U(*=ꢀT8458ꢀ5,0'+ꢀH(ꢀH(-(O454)'ꢀO,2ꢀ.8(ꢀ4-6(*.43).4,-ꢀ,Oꢀ
)
;
.8(ꢀ(OO(5.*ꢀ,Oꢀ58(145)'ꢀ*.205.02(ꢀ,6(2ꢀQ Gꢀ*('(5.46(ꢀ,<4+).4,-ꢀ
;
!
; G
GꢀVNQ;GZ=ꢀ*('(5.464.:ꢀ,Oꢀ*0'O02ꢀVGZ=ꢀ)-+ꢀ 2()5.4,-Cꢀ_02.8(21,2(=ꢀ.8(ꢀ1)**ꢀ.2)-*O(2ꢀ+024-3ꢀ.8(ꢀ5).)':.45ꢀ
*
)
0
*4-3ꢀ%KCꢀ]Paꢁ
-1ꢀV)*ꢀ*8,T-ꢀ4-ꢀ_4302(ꢀBHZꢀT4.8ꢀ84(2)25845)'':ꢀ>,2,0*ꢀ*.205.02(C
N&Gꢀ 1()*02(1(-.*ꢀ T(2(ꢀ >(2O,21(+ꢀ .,ꢀ 4-6(*.43).(ꢀ .8(ꢀ
CD,-.+ 8EF9GF
>
,-.?@A $
B
/ 'CHD,-.+ I29GF
J
K /HHꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀV]Z
*02O)5(ꢀ('(1(-.)'ꢀ5,1>,*4.4,-*ꢀ)-+ꢀH,-+4-3ꢀ5,-O4302).4,-*ꢀ,Oꢀ
CD.0-+ 8EF9GF
.
8(ꢀMP+,>(+ꢀ5)2H,-ꢀ-)-,O')U(*Cꢀ!8(ꢀ*026(:ꢀN&Gꢀ*>(5.2)ꢀV_4302(ꢀ
.
.?@A $ B/ ' CHD,-.+ I29GF 'CD,-.+ 8EF9GF J K /HHꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀVbZ
GDZꢀ*8,Tꢀ.8(ꢀ5,(<4*.(-5(ꢀ,Oꢀ('(1(-.)'ꢀ#ꢀV;a]ꢀ(`Z=ꢀMꢀVDEEꢀ(`Z=ꢀ@ꢀ
B]
CH K >,-. K .. K D,-.+ I29GF
L789ME9NEO7 '-P '/
V]DDꢀ(`Zꢀ4-ꢀ.8(ꢀ,H.)4-(+ꢀMP+,>(+ꢀ5)2H,-ꢀ-)-,O')U(*= ꢀT8458ꢀ4*ꢀ
q..ꢀ
?
A
$
ꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀVXZ
..ꢀ K F
5
,-*4*.(-.ꢀT4.8ꢀ.8(ꢀG!%dꢀ('(1(-.)'ꢀ1)>>4-3ꢀ2(*0'.*ꢀ)H,6(Cꢀ!8(ꢀ
CH K >,-. K .. K D,-.+ I29GF
?
TME9NEO4TU!VSP '/A
$
ꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀVaZ
#ꢀB*ꢀ*>(5.2)ꢀ,OꢀMP+,>(+ꢀ5)2H,-ꢀ-)-,O')U(*ꢀV_4302(ꢀGYZꢀ5,0'+ꢀH(ꢀ
+(5,-6,'0.(+ꢀ4-.,ꢀO46(ꢀ>()U*ꢀ5(-.2(+ꢀ).ꢀ)2,0-+ꢀ;aYCbꢀV#BZ=ꢀ
;a]CEꢀV#;Z=ꢀ;aXC]ꢀV#DZ=ꢀ;aEC7ꢀV#YZꢀ)-+ꢀ;EBCBꢀ(`ꢀV#]Z=ꢀT8458ꢀ5)-ꢀ
qQRFS
7
U!VS K F
p8(2(ꢀ_ꢀ)-+ꢀ_
-+ꢀ#G@;ꢀ2(O(2ꢀ.,ꢀ.8(ꢀ5,-5(-.2).4,-ꢀ,OꢀQ
02O)5(ꢀ)2()C
7
ꢀ)2(ꢀ.8(ꢀ,0.'(.ꢀ)-+ꢀ4-'(.ꢀ3)*c*ꢀO',Tꢀ2).(*rꢀ#Q;G
ꢀ
)
Gꢀ)-+ꢀG@ rꢀGGAꢁꢀ*>(54O45ꢀ
; ;
H(ꢀ)..24H0.(+ꢀ.,ꢀ#m#=ꢀ#PM=ꢀ#P@=ꢀ#m@=ꢀP#@@ꢀH,-+ꢀ)-+ꢀ.8(ꢀ*8)U(P
S
*
0>ꢀ hPh ꢀ .2)-*4.4,-ꢀ ,Oꢀ 5)2H,-=ꢀ 2(*>(5.46(':Cꢀ p8(-ꢀ >:2,':*4*ꢀ
,
.
(1>(2).02(ꢀ 4-52()*(*ꢀ O2,1ꢀ X77ꢀ .,ꢀ B777ꢀ #=ꢀ 32)>84.(P'4U(ꢀ
)2H,-ꢀV#BZꢀH(5,1(*ꢀ1,2(ꢀ+,14-)-.ꢀT84'(ꢀ0-*).02).(+ꢀ5)2H,-ꢀ
.205.02(*ꢀV#;Zꢀ+(52()*(=ꢀ*033(*.4-3ꢀ(-8)-5(+ꢀ32)>84.4[).4,-ꢀ
+(32((ꢀ,Oꢀ.8(ꢀMP+,>(+ꢀ5)2H,-ꢀ-)-,O')U(*ꢀ).ꢀ8438(2ꢀ>:2,':*4*ꢀ
8(ꢀ1,2>8,',3:ꢀ,Oꢀ.8(*(ꢀMP+,>(+ꢀ5)2H,-ꢀ-)-,O')U(*ꢀT)*ꢀ .(1>(2).02(*CꢀA*ꢀ*8,T-ꢀ4-ꢀ!)H'(ꢀGB=ꢀ.8(ꢀ-4.2,3(-ꢀ5,-.(-.*ꢀ
.0+4(+ꢀH:ꢀG%dꢀ)-+ꢀ.8(ꢀ2(>2(*(-.).46(ꢀ41)3(*ꢀ)2(ꢀ*8,T-ꢀ4-ꢀ 4-52()*(ꢀO2,1ꢀ;CXꢀ.,ꢀBECbꢀ).C^ꢀH:ꢀ.8(ꢀ1(')14-(ꢀ1)**ꢀO2,1ꢀ7ꢀ.,ꢀ
4302(ꢀB)ꢀ)-+ꢀGBCꢀA''ꢀ.8(ꢀ*)1>'(*ꢀ*8,Tꢀ)ꢀ*8((.ꢀ1,2>8,',3:ꢀT4.8ꢀ ]ꢀ3ꢀT84'(ꢀ+(52()*(ꢀO2,1ꢀ;;CEꢀ.,ꢀYC]ꢀ).C^ꢀT8(-ꢀ.8(ꢀ)--()'4-3ꢀ
5
5
!%63$%ꢀ1'+ꢀ+)%#6%%).'
*
0*1(1#$!()F1$).'ꢀ."ꢀ,-+./!+ꢀ#1(2.'ꢀ'1'."314!%
!
*
_
ꢀ
,
*
1,,.8ꢀ*02O)5(ꢀ(<5(>.ꢀ%dP7Pa77=ꢀ*033(*.4-3ꢀ.8(ꢀ4-+4*>(-*)H'(ꢀ .(1>(2).02(ꢀ4-52()*(*ꢀO2,1ꢀX77ꢀ.,ꢀB777 #Cꢀ!8(-ꢀ.8(ꢀN&GꢀMB*ꢀ
,'(ꢀ,Oꢀ1(')14-(ꢀ4-ꢀO,214-3ꢀ*1,,.8ꢀ*8((.ꢀ1,2>8,',3:Cꢀ!8(ꢀ *>(5.2)ꢀ ,Oꢀ MP+,>(+ꢀ 5)2H,-ꢀ -)-,O')U(*ꢀ T(2(ꢀ O02.8(2ꢀ
:2,':*4*ꢀ.(1>(2).02(ꢀ)'*,ꢀ>'):*ꢀ)-ꢀ41>,2.)-.ꢀ2,'(ꢀ,-ꢀ.8(ꢀ +(5,-6,'0.(+ꢀT4.8ꢀO,02ꢀ5,1>,-(-.*ꢀVMBꢁꢀ>:24+4-45ꢀMꢀ).ꢀDEaCBꢀ
,2>8,',3:ꢀ,Oꢀ.8(ꢀMP+,>(+ꢀ5)2H,-ꢀ-)-,O')U(*Cꢀ!8(ꢀ2(*0'.*ꢀ (`=ꢀM;ꢁꢀ>:22,'45ꢀMꢀ).ꢀY77CBꢀ(`=ꢀMDꢁꢀ32)>84.45ꢀMꢀ).ꢀY7BC]ꢀ(`ꢀ)-+ꢀ
2
>
1
YD
*
033(*.ꢀ.8).ꢀ8438(2ꢀ>:2,':*4*ꢀ.(1>(2).02(ꢀ'()+*ꢀ.,ꢀ.84--(2ꢀ)-+ꢀ MYꢁꢀ,<4+4[(+ꢀMꢀ).ꢀY7YCBꢀ(`Z ꢀ)-+ꢀ.8(ꢀ2(*0'.*ꢀ)2(ꢀ*8,T-ꢀ4-ꢀ_4302(ꢀ
*
1,,.8(2ꢀ*02O)5(ꢀV%dPDC]PX77ꢀ4-ꢀ_4302(ꢀGB+=ꢀ%dPDC]PE77ꢀ4-ꢀ DC
_4302(ꢀGB(ꢀ)-+ꢀ%dPDC]PB777ꢀ4-ꢀ_4302(ꢀGBOZ=ꢀ*4-5(ꢀ5,1>'(.(ꢀ
!
84*ꢀ/,02-)'ꢀ4*ꢀgꢀ!8(ꢀ ,:)'ꢀG,54(.:ꢀ,Oꢀ#8(14*.2:ꢀ;7<<
VUꢀ% 8.C=ꢀ;7;7=ꢀEE=ꢀBPB7ꢀfꢀJ
&
'()*(ꢀ+,ꢀ-,.ꢀ)+/0*.ꢀ1)234-*