• Aucun résultat trouvé

Application à l’analyse conformationnelle des N-oxy-pyrrolidines

que nous avons modifié afin de traiter :

- la fonction nitroxyle

- la pseudorotation des cycles à cinq chaînons (méthode développée par D. Cremer et J.A. Pople) - la fonction peroxydique

- l’effet anomère

Ces travaux ont fait l’objet de deux publications et trois communications par affiche.

!"#$"%&'()"#'* '#'*+,), "$ -./0&/&1/%/2 %)#3, 1+ &"*/45*'%

&/46'#)4,7 '88*)4'()"# (" #)(%"9)2/,

:)2)/% ;)%)

'<

=< >#"5? @'52/*0;)%)

'

< A'5* B"%2"

1 '

!"#$%"&$'%( )( *+','( -+(.$%'/0( (& 1$)(.2'3"&'$4 1$2(.502"'%(6 7189*:8; <=>?6 74'@(%3'&(. )( A%$@(45(6 *"3( BCD6 >EEF? 1"%3('22( *()(G DH6 I%"45(

1

!"#$%"&$'%( ;&%05&0%( (& 8(."5&'@'&(. )(3 J3K(L5(3 A"%","M4(.&'/0(36 7189*:8; <=>?6 74'@(%3'&(. )( A%$@(45(6 *"3( =D>6 >EEF? 1"%3('22( *()(G DH6 I%"45(

C/4/)./2 DE F5*+ GEEHI '44/8(/2 J K"./&1/% GEEH

!"#$%&'$

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

N(OP$%)37 N"*/45*'% &/46'#)4,I A,/52"%"('()"# ,5%$'4/I U)./0&/&1/%/2 %)#3,I K)(%"9)2/,I P;C

() *+$%,-.'$/,+

N'#+ '&)#"9+* %'2)4'*, Q#)(%"9)2/,R '%/ ,('1*/ ,8/4)/, 5#2/% "%2)#'%+ 4"#2)()"#, '#2 '%/ O)2/*+ 5,/2 )# ,8)#0*'1/*)#3 '#2 ,8)#0(%'88)#3 /98/%)&/#(, VHWDXM B6), ,('1)*)(+ 6', '**"O/2 (" 2/(/%&)#/ ,"&/ ,(%54(5%'* 8'%'&/(/%, "$ #)(%"9)2/, 1+ Y0%'+ 4%+,('*0 *"3%'86)4 &/(6"2, VZWHEXM N"%/"./%< ' *'%3/ #5&1/% "$ ,('1*/ "% 8/%,),(/#( -./0&/&1/%/2 %)#3 '&)#"9+* %'2)4'*, Q;46/&/ HR 6'./ 1//# 46'%'4(/%)[/2 1+ P;C ,8/4(%",4"8+ VHH<HGXM B6/ P;C 8'%'&/(/%, "$ '&)#"9+* %'2)4'*, 2/8/#2 2)%/4(*+ "# (6/ 3/"&/(%+ "$ (6/ $'."%/2 4"#$"%&/%,< '#2 &"*/45*'% &/46'#)4, ), 6/*8$5* (" 2/(/%&)#/ (6/,/ 3/"&/(%)/,M

\# (6/ *)(/%'(5%/< ' *"( "$ ,)&8*/ '&)#"9+* %'2)4'*, 6'./ 1//# ,(52)/2 O)(6 6)36 */./* ]5'#(5& &/46'#)4, &/(6"2,< /,,/#()'**+ (" /,()&'(/ (6/)% /]5)*)1%)5& 3/"&/(%+ '#2 ,8)# 2/#,)()/,< 15( $/O &"*/45*'% &/46'#)4, O"%?, 6'./ 2/'*( O)(6 '&)#"9+* %'2)4'*, VHDWH^X '#2 "$(/# 4"#,),( "$ $"%4/ -/*2 8'%'0 &/(%)['()"#,M

_# (6/ "(6/% 6'#2< -./0&/&1/%/2 %)#3, '%/ ./%+ `/9)1*/ &"*/45*/, '#2 (6/)% "5( "$ 8*'#/ &"()"# 6', 1//# O)2/*+ ,(52)/2 1+ ]5'#(5& &/46'#)4, &/(6"2, VHaWGHXM B6/ %)#3 4"#$"%&'()"#, '%/ 5,5'**+ 2/,4%)1/2 1+ (6/ &/'# "$ (O" &"2/*, 1',/2 "# /)(6/% )#(%'4+4*)4 2)6/2%'* '#3*/, VGG<GDX "% 2),8*'4/&/#(, 8/%8/#2)45*'% (" '# )#.'%)'#( &/'# 8*'#/ VGZWG^XM N"*/45*'% 2+#'&)4 ,)&5*'()"#, 6'./ 1//# 4'%%)/2 "5( "#*+ "# 4+4*"8/#('#/ VGa<GbX 15( ,"&/ 4"#$"%&'0 ()"#'* '#'*+,/, 1+ &"*/45*'% &/46'#)4, "$ .'%)"5, -./0&/&1/%/2 %)#3 4"&8"5#2, "$ 1)"*"3)4'* )#(/%/,(

F"5%#'* "$ N"*/45*'% ;(%54(5%/ QB6/"46/&R caG QGEEGR H^HWHac

EHJJ0HGaEdEGde 0 ,// $%"#( &'((/%! GEEG P*,/.)/% ;4)/#4/ SMTM >** %)36(, %/,/%./2M A\\7 ; E H J J 0 H G a E Q E H R E E ^ ^ D 0 Z

OOOM/*,/.)/%M4"&d*"4'(/d(6/"46/&

= !"%%/,8"#2)#3 '5(6"%M B/*M7 !DD0ZbHG0aaZ0HZI $'97 !DD0ZbHb0aac0HGM

O/%/ %/8"%(/2 VDEWDDXM B6/ &')# '2.'#('3/ "$ &"*/0 45*'% &/46'#)4, &/(6"2, ), (6/ ,6"%( %/]5/,(/2 ()&/ "$ 4'*45*'()"# (6'( '**"O, (6/ 4"#$"%&'()"#'* ,(52+ "$ *'%3/ &"*/45*/,M

\# ' 8%/4/2/#( 8'8/% VHcX< O/ 2/,4%)1/2 (6/ %/,5*(, "$ ' &"*/45*'% &/46'#)4, &"2/*)#3 "$ -./0&/&1/%/2 '&)#"9+* %'2)4'*, 5,)#3 1"(6 @/#N"* VDZX '#2 NNG VDc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

0)

12$3,-B6/ '.')*'1*/ /98/%)&/#('* 2'(' $"% 8+%%"*)2)#/0:0 "9+* %'2)4'*, '%/ (6/ P;C 6+8/%-#/ 4"58*)#3 4"#,('#(, Q6$44R 1/(O//# (6/ 5#8')%/2 /*/4(%"# '#2 (6/ '("&, O)(6 ' #"#0[/%" #54*/'% ,8)#M B6/ B_NPC QG<c<c0(%)&/(6+*0 c02)/(6"9+86",86"%+*08+%%"*)2)#/0H0"9+*R P;C ,8/40 (%5& ), %/8"%(/2 "# U)3M HM B6/ ,)9 &')# *)#/, %/,5*( $%"& (6/ 4"58*)#3 O)(6 (6/ HZK!"K " HD!^ @# '#2DH A !"A " cE!E @# #54*/) '#2 '%/ '44"&8'#)/2 "$ ,'(/**)(/ *)#/, 25/ (" 'HD! 4"58*)#3M U"% '#+ @/#N"* 4'*45*'(/2 4"#$"%&'()"#< (6/ !0 6$44 '%/ "1(')#/2 $%"& (6/ g/**/%WN4!"##/** %/*'()"# VDaX7 "Y" RY4",G"YO6/%/"Y), (6/ 2)6/2%'* '#3*/ "$ (6/ Y ,51,()(5/#( O)(6 (6/ #)(%"3/# 8S "%1)('* Q;46/&/ GR7 RA " ca!D @" R!" b!J @ VDbXM U"% ' ,/( "$ 4"#$"%&/%, )# S"*([&'## 8%"8"%()"#,< (6/ S"*([&'## O/)36(/2 !06$44 O/%/ 4'*45*'(/2 '#2 2)%/4(*+ 4"&8'%/2 (" (6/ /98/%)&/#('* "#/,M

\# "%2/% (" 8/%$"%& ' ]5'#()('()./ 4"#$"%&'()"#'* '#'*+,), "$ 854?/%/2 -./0&/&1/%/2 %)#3,< (6/ &/(6"2

BT ;'%' (& "2T U V$0%4"2 $W 1$2(502"% ;&%05&0%( X-+($5+(,Y =ZD XDHHDY >?>[>Z= H^G

;46/&/ HM

U)3M HM P;C ,8/4(%5& "$ B_NPC %/4"%2/2 )# 1/#[/#/ '( %""& (/&8/%'(5%/M ;46/&/ GM

2/./*"8/2 1+ !%/&/% '#2 A"8*/ VGZWGJX 6', 1//# )&8*/&/#(/2 )# @/#N"*< )# (6/ ,'&/ O'+ ', 2)2 U%/#46 '#2 B%'# VG^X $"% $5%'#",/ %)#3, O)(6 NNAGQacRM B6), &/(6"2 ), 1',/2 "# (6/ 2/-#)()"# "$ ' &/'# 8*'#/ (6'( ), )#.'%)'#( 25%)#3 (6/ 8,/52"%0 "('()"#M U"% '#+ 4"#$"%&'()"# "$ (6/ %)#3< (6/ \]4""%0 2)#'(/ "$ (6/ ](6 '("& "$ (6/ %)#3 &/',5%/, )(, 2),8*'4/&/#( "5( "$ (6/ &/'# 8*'#/ Q;46/&/ DR '#2 ), O%)((/# QP]M HR7 \] " !!! G c " /4", Z#!] " H# c !$ # $ $ !$E! G#% !H#

/!$E!D! E!c ">% $"% &",( "$ (6/ -./0&/&1/%/2 %)#3, O6/%/ / %/8%/,/#(, (6/ 854?/%)#3 '&8*)(52/ "$ (6/ %)#3 '#2 $ 2/,4%)1/, (6/ %)#3 4"#$"%&'()"# QU)3M GRM B6/ \] 2),8*'4/&/#(, '%/ #"%&'*)[/2 ," (6'( %c

]"H\G] " /G '#2 (6/ %)#3 &'+ '2"8( '# )#-#)(+ "$ 4"#$"%&'()"#, O6/# $ .'%)/, $%"& E (" DJE#M A5%/ (O),( QBR '#2 /#./*"8/ QPR 4"#$"%&'()"#, '%/ ,8'4/2 1+ Ha#M \# 4+4*"8/#('#/< (O" 4"#$"%&'()"#, '( $ '#2 $ ! # '%/ ,+&&/(%)4 ("O'%2 (6/ 8*'#'% %)#3 '#2 (6), )#(/%4"#./%,)"# &'+ "445% 1+ )#./%0 ,)"# Q(6%"536 (6/ 8*'#'% $"%&R "% 8,/52"%"('()"#M g"O/./%< (6/ 1'%%)/% (" 8*'#'%)(+ ), 5,5'**+ 6)36/% (6'# (6/ 8,/52"%"('()"#'* 1'%%)/%< )$ (6/ *'((/% /9),(,M L)(6 '#+ .'*5/ "$ (6/ 854?/%)#3 '&8*)(52/ / '#2 "$ (6/ 8,/52"%"('()"# '#3*/% < (6/ 4"%%/,8"#2)#3 4"#$"%0 &'()"# "$ ' -./0&/&1/%/2 %)#3 &'+ 1/ '5("&'()4'**+ 15)*( 1+ @/#N"* ', $"**"O,7

Q'R B6/ &"*/45*/ ), 8*'4/2 )# (6/ 4""%2)#'(/ ,+,(/& 2/-#/2 )# ;46/&/ Z7

BT ;'%' (& "2T U V$0%4"2 $W 1$2(502"% ;&%05&0%( X-+($5+(,Y =ZD XDHHDY >?>[>Z= H^D

;46/&/ DM \#.'%)'#( &/'# 8*'#/ '#2 \ 2)%/4()"# "$ (6/ 8,/52"%"('0 ()"#'* 2),8*'4/&/#(M

(6/ "%)3)# ), '( (6/ -./0&/&1/%/2 %)#3 3/"&/(%)4 4/#(/%M (6/ _GO 8*'#/ ), 2/-#/2 1+ (6/ %)#3 &/'# 8*'#/M (6/ _O '9), 3"/, (6%"536 (6/ 8%"i/4()"# "$ (6/ -%,( '("& "$ (6/ %)#3 )# (6/ %)#3 &/'# 8*'#/M "' " G#!' " H#c $"% '" H" ^" c # _G"&c '"H #/_ 4", "' _O# "&c '"H #/_ ,)# "' O6/%/ #/ ), (6/ ./4("% 4"%%/,8"#2)#3 (" (6/ '(6 '("& # _\" #_G ! #_O Q1R U"% /'46 4"58*/!/" $#" (6/ \ 4""%2)#'(/ "$ /'46 %)#3 '("& ), &"2)-/2 '44"%2)#3 (" P]M QHR Q4R B6/#< /'46 ,51,()(5/#( 1"5#2 (" /'46 %)#3 '("& ' 5#2/%3"/, (6/ &"./&/#( "$ (6/ '("& 'M

Q2R U)#'**+< (6/ "1(')#/2 4"#$"%&'()"# ), "8()&)[/2 1+ ,(/%)4 /#/%3+ &)#)&),'()"#M

BO" '5("&'()4 4"#$"%&'()"#'* '#'*+,), 8%"4/25%/, 6'./ 1//# )&8*/&/#(/2 )# @/#N"*7

B6/ -%,( 8%"4/25%/ ), /96'5,()./7$ .'%)/, $%"& E (" Dcb# O)(6 ' ,(/8 "$ "#/ 2/3%// '#2 / .'%)/, $%"& E (" H >j O)(6 ' ,(/8 "$ EMH >jM > 8,/52"0 %"('()"#'* ,5%$'4/ )#4*52)#3 DbJE 4"#$"%&'()"#, ), 4"#,(%54(/2 '#2 (6/ @/#N"* .'*5/, "$ (6/ 8,/50 2"%"('()"#'* '#2 %)#3 8*'#'%)(+ 1'%%)/%, '%/ "1(')#/2M > 8"(/#()'* /#/%3+ 45%./ ), /9(%'4(/2 $%"& (6), ,5%$'4/ )$ $"% /'46 .'*5/ "$ $ < O/ 4"#,)2/% "#*+ (6/ &",( ,('1*/ 4"#$"%&'()"#M \( ), )#(/%/,()#3 (" #"(/ (6'( (6), 8"(/#()'* /#/%3+ 45%./ ('?/, )#(" '44"5#( (6/

BT ;'%' (& "2T U V$0%4"2 $W 1$2(502"% ;&%05&0%( X-+($5+(,Y =ZD XDHHDY >?>[>Z= H^Z ;46/&/ ZM :/-#)()"# "$ (6/ 4""%2)#'(/ ,+,(/&M ;46/&/ cM *7 !+4*"8/#('#/< **7 !+4*"8/#('#"#/< ***7 N/(6+*04+4*"0 8/#('#/M B'1*/ H @/#N"* $"%4/ -/*2 8'%'&/(/%, ;(%/(46)#3 8'%'&/(/%, S"#2 (+8/ %EQ>j R `%Q&2+# >j"HR !!_ HMGEa HEMa !Q,8DRW!Q,8DR HMcGD ZMZ !Q,8GRW!Q,8DR HMZb^ ZMZ S/#2)#3 8'%'&/(/%, S"#2 '#3*/ "EQ2/3R `"Q&2+# >j %'2"GR !Q,8DRW!Q,8DRW!Q,8DR HEaME EMZc !Q,8DRW!Q,8GRW!Q,8DR HHJMJ EMZE !Q,8DRW!Q,8GR!_ HGGMc EMZJ B"%,)"#'* 4"#,('#(,

B"%,)"# '#3*/ aHQ?F &"*"HR aGQ?F &"*"HR aDQ?F &"*0HR

!Q,8DRW!Q,8DRW!Q,8DRW!Q,8DR EMGEE EMG^E EMEbD

!Q,8DRW!Q,8DRW!Q,8DRW!Q,8GR EMH^E EMG^E EMEbD

BT ;'%' (& "2T U V$0%4"2 $W 1$2(502"% ;&%05&0%( X-+($5+(,Y =ZD XDHHDY >?>[>Z= H^c

U)3M DM A,/52"%"('()"#'* ,5%$'4/ "$ 4+4*"8/#('#/M BO" 4"#("5% *)#/, '%/ JMc ?F &"*"H'8'%(M U"% 4*'%)(+< '** ,5%$'4/, '%/ [""&/2 "# (6/ &)#)&'M

U)3M ZM A,/52"%"('()"#'* ,5%$'4/ "$ 4+4*"8/#('#"#/M BO" 4"#("5% *)#/, '%/ JM^ ?F &"*"H'8'%(M

.'%)'()"# "$ / 25%)#3 (6/ 8,/52"%"('()"#M \# (6/ 4',/ "$ 8+%%"*)2)#/0:0"9+* %'2)4'*,< (6), 8,/52"8"(/#()'* $5#4()"# O', 4"&8'%/2 O)(6 (6/ 8,/52"%"('()"#'* 8"(/#()'* '44"%2)#3 (" (6/ C"4?/#1'5/%k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

ET>T *$4W$%,"&'$4"2 "4"2O3'3 $W 045%$P)() b@(9 ,(,#(%() %'4M3

>( -%,(< O/ (/,(/2 "5% $5** 4"#$"%&'()"#'* '#'*+,),

8%"4/25%/ O)(6 (6%// ,)&8*/ -./0&/&1/%/2 %)#3, $"% O6)46 /98/%)&/#('* 2'(' '1"5( (6/ 8,/52"%"('()"# O/%/ 851*),6/2 Q;46/&/ cRM @/#N"* $"%4/ -/*2 8'%'0 &/(/%, 5,/2 $"% (6/,/ 4'*45*'()"#, '%/ %/8"%(/2 )# B'1*/ HM !+4*"8/#('#/ * ), (6/ ,&'**/,( "#/ '#2 %/8%/0 ,/#(, (6/ 1',)4 (/,( "$ (6/ $"%4/ -/*2< 4+4*"8/#('#"#/ ** ), ' &"2/* "$ 8+%%"*)2)#/0:0"9+* %'2)4'*, 1/4'5,/ "$ (6/ 8*'#'%)(+ "$ (6/ 4'%1"#+* $5#4()"#M >( *',(< (6/

BT ;'%' (& "2T U V$0%4"2 $W 1$2(502"% ;&%05&0%( X-+($5+(,Y =ZD XDHHDY >?>[>Z= H^J

B'1*/ G

S'%%)/%, (" 8*'#'%)(+ $"% *< ** '#2 *** Q;46/&/ cR

@/#N"* 1'%%)/% Q?F &"*"HR NNG 1'%%)/% VZcX Q?F &"*"HR P98/%)&/#('* 1'%%)/% Q?F &"*"HR

* H^MG HbMJ GHMJ VZHX ** HcMc HDMD HJM^ VZZX *** GHMb W W B'1*/ D !"#(%)15()"#, (" (6/ ,(/%)4 /#/%3+ "$ (6/ &'i"% 4"#$"%&/%, ;(/%)4 /#/%3+'Q?F &"*"HR J.2L J/*/4(%",('()4 J,(%/(46)#3 J1/#2)#3 J("%,)"#

* "EM^ "EMG EMH DMJ "HbM^

** EMH EMG EMb cMG "GEMJ

*** "DMD "EMG "EMD GMG "GEMc

'

C/*'()./ (6/ 8*'#'% 4"#$"%&'()"#M

U)3M ^M T'%)'()"# "$ (6/ ,(/%)4 /#/%3+ '#2 "$ (6/ 854?/%)#3 '&8*)(52/ $"% *** "# (6/ 8,/52"%"('()"#'* 8'(6O'+M U"% /'46 .'*5/ "$$< "#*+ (6/ 4"#$"%&'()"# O)(6 (6/ *"O/,( ,(/%)4 /#/%3+ ), 4"#,)2/%/2M U)3M JM T'%)'()"# "$ (6/ ,(/%)4 /#/%3+ '#2 "$ (6/ 854?/%)#3 '&8*)(52/ $"% ** "# (6/ 8,/52"%"('()"#'* 8'(6O'+M U"% /'46 .'*5/ "$$< "#*+ (6/ 4"#$"%&'()"# O)(6 (6/ *"O/,( ,(/%)4 /#/%3+ ), 4"#,)2/%/2M

8%/$/%%/2 4"#$"%&/%, "$ &/(6+*04+4*"8/#('#/ *** &5,( 6'./ (6/ &/(6+* ,51,()(5/#( )# /]5'("%)'* 8",)()"# VHbXM B6/ 8,/52"%"('()"#'* ,5%$'4/, '%/ %/8"%(/2 "# U)3,M DWcM B6/ 4'*45*'(/2 1'%%)/%, (" 8*'#'%)(+ '%/ ,*)36(*+ 5#2/%/,()&'(/2 15( (6/ %/*'()./ .'*5/, O/%/ )# '3%//0 &/#( O)(6 (6/ #5&1/% "$ /4*)8,/2 1"#2, )# (6/ 8*'#'% $"%&7 4+4*"8/#('#"#/ $ 4+4*"8/#('#/ $ &/(6+*0 4+4*"8/#('#/ QB'1*/ GRM N"%/"./%< (6/ 4'*45*'(/2 QHMHR '#2 /98/%)&/#('* QHMDR 1'%%)/% 6/)36( %'()" *d** O/%/ )# 3""2 '3%//&/#(M \# (6/ 8*'#'% $"%&< (6/ &'i"% 8'%( "$ (6/ ,(/%)4 /#/%3+ %/8%/,/#(, (6/ ("%,)"#'* ,(%')# "$ (6/ )#(%'4+4*)4 2)6/2%'* '#3*/, '#2 O', (65, ]5)(/ 4"#,('#( )# (6/ (6%// 4',/, QB'1*/ DRM >, /98/4(/2< (6/ .'# 2/% L''*, )#(/%'4()"#, '#2 (6/ ("%,)"#'* /#/%3+ 2/4%/',/2 O6/# (6/ %)#3 854?/%, '#2 (6/ 1/#2)#3 /#/%3+ )#4%/',/2 1/4'5,/ (6/ )#(%'4+4*)4 1"#2 '#3*/, 3/( 'O'+ $%"& (6/ )2/'* .'*5/ "$ HEb#M

>44"%2)#3 (" U)3M D< (6/ $%// 8,/52"%"('()"# "$ * ), O/** %/8%"254/2M B6/ 8,/52"%"('()"# "445%, '( ' 4"#,('#( .'*5/ "$ / QEMZ >j R< )# '3%//&/#( O)(6 (6/ /98/%)&/#('* /,()&'(/2 .'*5/ VZEWZDX QEMZDW EMZa >j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`'( '%"5#2 (6/ H P 4"#$"%&/%< ', 8%".)2/2 1+Hg KNC )#./,()3'()"#, VHbXM g"O/./%< '44"%2)#3 (" %/4/#( /98/%)&/#('* 2'('

BT ;'%' (& "2T U V$0%4"2 $W 1$2(502"% ;&%05&0%( X-+($5+(,Y =ZD XDHHDY >?>[>Z= H^^ B'1*/ Z

!'*45*'(/2 8,/52"%"('()"#'* 1'%%)/%,

/Q>j R N)#)&5& N'9)&5& S'%%)/% Q?F &"*"HR

;(/%)4 /#/%3+ Q?F &"*"HR l"4'()"# ;(/%)4 /#/%3+ Q?F &"*"HR l"4'()"# * EMZ ZGMD W W W E ** EMZ DJMJ DBZ<ZBD ZGME HP< PH cMZ' *** EMDWEMZ ZJMG HP caM^ GBHdGP HGMc cPdcBH '

P98/%)&/#('* 1'%%)/%7 HJMG ?F &"*"H$"% (6/ 3%"5#2 ,('(/ '#2 ^MG ?F &"*"H$"% (6/ /94)(/2 ;H,('(/ VZZXM

B'1*/ c @/#N"* $"%4/ -/*2 8'%'&/(/%, $"% 8+%%"*)2)#/0:0"9+* %'2)4'*, ;(%/(46)#3 8'%'&/(/%, S"#2 (+8/ %EQ>j R `%Q&2+# >j"HR KW_" HMGGGG cMbE KW!Q,8DR HMZ^EE DMcG S/#2)#3 8'%'&/(/%, S"#2 '#3*/ "EQ2/3R `%Q&2+# >j %'2"GR !Q,8DRWKW!Q,8DR HHGME EM^E KW!Q,8DRW !Q,8DR HEDME EMZE !Q,8DRW KW_" HGEME EMcJ B"%,)"#'* 4"#,('#(,

B"%,)"# '#3*/ aHQ?F &"*"HR aGQ?F &"*"HR aDQ?F &"*"HR

!Q,8DRW!Q,8DRWKW_" E E E

'1"5( ** VZZX< @/#N"* 8,/52"%"('()"#'* 1'%%)/%, ,//& (" 1/ 5#2/%/,()&'(/2 QB'1*/ ZRM \# ,5&&'%+< @/#N"* 8%".)2/, ' $',( 4"#$"%&'()"#'* '#'*+,), "$ -./0 &/&1/%/2 %)#3, O)(6 4"#$"%&/%, )# 3""2 '3%//&/#( O)(6 (6/ /98/%)&/#('* 2'('7 "#*+ (6/ ]5'#()('()./ /,()0 &'()"#, "$ (6/ 8,/52"%"('()"#'* 1'%%)/%, 2),'3%// O)(6 /98/%)&/#('* 2'(' 15( (6/ 4"&8'%),"# "$ (6/ 1'%%)/% 6/)36(, 8%".)2/, )#$"%&'()"#, '1"5( (6/ ,(/%)4 6)#2%'#4/ )# (6/ .'%)"5, (/,(/2 -./0&/&1/%/2 %)#3,M g"O/./%< )$ (6/ 8%/$/%%/2 4"#$"%&'()"#, '%/ 3"./%#/2 1+ 85%/ /*/4(%"#)4 $'4("%, *)?/ )# (6/ 5#,51,()(5(/2 8+%%"*)2)#/ VGHX< &"*/45*'% &/46'#)4, &/(6"2, '%/ #"( '88%"8%)'(/ "% ' ,8/4)-4 8'%'&/(%)['()"# "$ (6/ $"%4/ -/*2 &5,( 1/ 4"#,)2/%/2 Q/M3M '#"&/%)4 /$$/4(RM ETDT AO%%$2')'4(9:9$GO2 %")'5"23 U"%4/ -/*2 8'%'&/(/%, $"% 8+%%"*)2)#/0:0"9+* %'2)4'*, '%/ ,5&&'%)[/2 )# B'1*/ cM \( ), #"( #/4/,,'%+ (" )#(%"254/ )&8%"8/% ("%,)"#'* 8'%'0 &/(/%, $"% 8+%%"*)2)#/0:0"9+* %'2)4'*, 1/4'5,/ (6/ '&)#"9+* $5#4()"# ), ',,5&/2 (" 1/ 8*'#'% VHD<ZJX )# -./0&/&1/%/2 %)#3, Q;46/&/ JRM \$ O/ 4"#,)2/% ,"&/ ,(%54(5%'* 8'%'&/(/%, "$ AC_Yml QG<G<c<c0(/(%'&/(6+*08+%%"*)2)#/0:0"9+*R

Q;46/&/ ^R< @/#N"* 3/"&/(%+ O', )# 3""2 '3%//0 &/#( O)(6 (6/ /98/%)&/#('* 2'(' '#2 (6/ %/,5*(, "1(')#/2 O)(6 2)$$/%/#( &/(6"2, QB'1*/ JRM ;('%()#3 $%"& (6/ GE 85%/ 4"#$"%&'()"#,< ' 1%)/$ 4"#$"%&'0 ()"#'* '#'*+,), O', 4'%%)/2 "5( "# B_NPC VHc<HJX QG<c<c0(%)&/(6+*0G02)/(6"9+86",86"%+*08+%%"*)2)#/0 :0"9+*R '#2 (6/ (O" 2)',(/%/"),"&/%, "$ B_SPC VHc<HJX QG<c<c0(%)&/(6+*0G02)/(6"9+86",86"%+*0Z0 86/#+*08+%%"*)2)#/0:0"9+*R (" 2/(/%&)#/ (6/ 1/,( "%)/#('()"# "$ (6/ 2)/(6"9+86",86"%+* &")/(+M B6/ $5** '5("&'()4 8%"4/25%/ O', (6/# '88*)/2 (" (6/ $"5% ,('1*/ 8+%%"*)2)#/0:0"9+* %'2)4'*, %/8%/0 ,/#(/2 "# ;46/&/ ^M B6/ '#'*+,), "$ (6/ 8,/52"%"('()"#'* ,5%$'4/, 4*/'%*+ ,6"O, (O" &'i"% 4"#$"%&/%, $"% AC_Yml

BT ;'%' (& "2T U V$0%4"2 $W 1$2(502"% ;&%05&0%( X-+($5+(,Y =ZD XDHHDY >?>[>Z= H^a

;46/&/ JM B"%,)"#'* '#3*/, '%"5#2 (6/ '&)#"9+* $5#4()"# )# 8+%%"0 *)2)#/0:0"9+* %'2)4'*,M

;46/&/ ^M AC_Yml7 G<G<c<c0(/(%'&/(6+*08+%%"*)2)#/0:0"9+*< B_NPC7 G<c<c0(%)&/(6+*0G02)/(6"9+86",86"%+*08+%%"*)2)#/0:0 "9+*< B_SPC7 G<c<c0(%)&/(6+*0G02)/(6"9+86",86"%+*0Z086/#+*0 8+%%"*)2)#/0:0"9+*M

B'1*/ J

!"&8'%),"# "$ ,"&/ ,(%54(5%'* 8'%'&/(/%, "$ AC_YmlM AND 4'*45*'()"#, O/%/ 8/%$"%&/2 O)(6 >NA>! JMcc VZaX '#2 :UB 4'*45*'()"#, O)(6 !"#$$%"&bZ VZbX

P98 VccX @/#N"* NNGQaaR AND VZ^X SDlmAdJ0DH@!

KW_ Q>j R HMG^GQDR HMG^Z HMDH^ HMGZG HMG^J

!WK Q>j R HMZaZQDR HMZbJ HMZaJ HMcGZ HMZbE

BT ;'%' (& "2T U V$0%4"2 $W 1$2(502"% ;&%05&0%( X-+($5+(,Y =ZD XDHHDY >?>[>Z= H^b

U)3M aM A,/52"%"('()"#'* ,5%$'4/ "$ AC_YmlM BO" 4"#("5% *)#/, '%/ HDME ?F &"*"H'8'%(M

U)3M bM A,/52"%"('()"#'* ,5%$'4/ "$ B_NPCM BO" 4"#("5% *)#/, '%/ HHME ?F &"*"H'8'%(M

'#2 B_NPC '#2 ' ,)#3*/ 4"#$"%&/% $"% /'46 2)',(/%0 /"),"&/% "$ B_SPC QU)3,M aWHHRM B6/ ,+&&/(%+ "$ AC_Yml ), O/** %/8%"254/2 ,)#4/ O/ 6'./ (O" /]5).'*/#( O/**,< '#2 (6/ 86",86"%+*'(/2 4"&8"5#2, 6'./ 46'%'4(/%),()4 $/'(5%/,M B6/ %/,5*(, '%/ /',)/% (" )#(/%8%/( "# U)3,M HG '#2 HD< ,6"O)#3 (6/ 8,/52"%"('0 ()"#'* 8'(6O'+M U"% AC_Yml '#2 B_NPC< (6/ 46/&)4'* /946'#3/ "445%, 1/(O//# (O" (O),( 4"#$"%0 &/%, QDBZ '#2 ZBDR '#2 (6/ 8,/52"%"('()"#'* 1'%%)/% 6/)36(, '%/ HZ '#2 HJ ?F &"*"H< %/,8/4()./*+M \# $'4(< '44"%2)#3 (" (6/ .'%)'()"# "$ (6/ 854?/%)#3 '&8*)(52/ QU)3,M HG '#2 HDR< (6), ), #"( ' 8,/52"%"('()"# '#+&"%/ 15( ' 8,/52")#./%,)"# "% '# )#./%,)"# 25/ (" (6/ $"5% !0,51,()(5/#(, "# !G'#2 !cM B6/ 2)/(6"9+86",86"%+* &")/(+ "$ B_NPC ), )# ' 8,/52"'9)'* 8",)()"# O6/%/', )( ), ' 15*?+ ,51,()(5/#(M B6), 8%/$/%/#()'* "%)/#('()"# ), '((%)15(/2 (" ' ,('1)*)[0 )#3 '#"&/%)4 /$$/4( VcEWcDX 1/(O//# (6/ /*/4(%"#/3'0 ()./ 2)'*?+*86",86"%+* 3%"58 VcZX '#2 (6/ '&)#"9+* $5#4()"# Q;46/&/ aRM \# (6/ 4',/ "$ B_SPC< (6/%/ ), #/)(6/% 8,/52"%"('0 ()"# #"% )#./%,)"# QU)3,M HE '#2 HHR 1/4'5,/ "$ (6/ 86/#+* ,51,()(5/#( "# !Z< O6)46 ), 1*"4?/2 )# '# /]5'0 ("%)'* 8",)()"# '#2 8%/./#(, '#+ 4"#$"%&'()"#'* /946'#3/ Q(6/ 4'*45*'(/2 1'%%)/%, '%/ ZD '#2 Za ?F &"*"H $"% B_SPC 5'3 '#2 B_SPC &%"43< %/,8/4()./*+RM \# B_SPC &%"43< (6/%/ ), ' ,+#/%3+ 1/(O//# (O" ,('1)*)[)#3 /$$/4(, Q/]5'("%)'* 86/#+* '#2 '#"&/%)4 /$$/4(R O6/%/', (6/,/ (O" )#(/%'4()"#, '%/ $KK$3'&( )# B_SPC 5'3 Q/]5'("%)'* 86/#+* "%

BT ;'%' (& "2T U V$0%4"2 $W 1$2(502"% ;&%05&0%( X-+($5+(,Y =ZD XDHHDY >?>[>Z= HaE

U)3M HHM A,/52"%"('()"#'* ,5%$'4/ "$ B_SPC &%"43M BO" 4"#("5% *)#/, '%/ HDMZ ?F &"*"H'8'%(M

U)3M HGM T'%)'()"# "$ (6/ ,(/%)4 /#/%3+ '#2 "$ (6/ 854?/%)#3 '&8*)0 (52/ $"% AC_Yml "# (6/ 8,/52"%"('()"#'* 8'(6O'+M U"% /'46 .'*5/ "$$< "#*+ (6/ 4"#$"%&'()"# O)(6 (6/ *"O/,( ,(/%)4 /#/%3+ ), 4"#,)20 /%/2M

U)3M HDM T'%)'()"# "$ (6/ ,(/%)4 /#/%3+ '#2 "$ (6/ 854?/%)#3 '&8*)0 (52/ $"% B_NPC "# (6/ 8,/52"%"('()"#'* 8'(6O'+M U"% /'46 .'*5/ "$$< "#*+ (6/ 4"#$"%&'()"# O)(6 (6/ *"O/,( ,(/%)4 /#/%3+ ), 4"#,)20 /%/2M

'#"&/%)4 /$$/4(RM >, /98/4(/2< (6/ ,(/%)4 )#(/%'4()"# 2"&)#'(/, '#2 */'2, (" ' -#'* 4"#$"%&'()"# O)(6 ' 8,/52"/]5'("%)'* 86",86"%5,M

\( ), )#(/%/,()#3 (" #"(/ (6'( B_SPC 5'3 '#2 B_SPC &%"43"$ (6/ 86",86"%5, 4"58*)#3 '%/ '*&",( )#2/8/#0 2/#( "$ (6/ (/&8/%'(5%/ !"A " "c!a " HE"D- ! cD!EJ#! B6), (%/#2 ), )# '3%//&/#( O)(6 (6/ /9),(/#4/ "$ ' *'%3/*+ &'i"% 4"#$"%&/% $"% (6/,/ %'2)4'*,M g"O/./%< $"% (6/ B_NPC< (6/ .'%)'()"# "$ "A ), ,)3#)-4'#( !"A " "Hb!J " HE"D

- !cE!c^#" )# '3%//0

&/#( O)(6 (6/ /9),(/#4/ "$ ' %'8)2 /946'#3/ 1/(O//# (O" 4"#$"%&/%, O)(6 2)$$/%/#( "A.'*5/,M

ETET *$,K"%'3$4 $W &+( &P$ K3(0)$%$&"&'$4"2 K$&(4&'"23 > ,/&)04*',,)4'* '88%"'46 1',/2 "# (6/ ,)&5*'()"# "$ P;C ,8/4(%' '( 2)$$/%/#( (/&8/%'(5%/, 6', 1//# 2/./*"8/2 VDJ<D^XM U%"& (6/ /98/%)&/#('* !06$44 '#2 (/&8/%'(5%/ 4"/$-4)/#(,< ' 8,/52"8"(/#()'* ), /,('1*),6/27 a!$# " aH G !H " 4",!$ " $H## ! aG G !H " 4", G!$ " $G##

O6/%/ aH< aG< $H '#2 $G 8'%'&/(/%, '%/ '2i5,(/2 (" %/8%"254/ (6/ /98/%)&/#('* 2'('M B6/ 8,/52"8"(/#()'* '**"O, (" 2/(/%&)#/ (6/ #'(5%/ "$ (6/ 4"#$"%&/%, Q%/*'()./ /#/%3)/, '#2 S"*([&'## 8%"8"%()"#,R '#2 (6/ 8,/52"%"('()"#'* 1'%%)/%M B6/ .'%)'()"# "$ (6/

BT ;'%' (& "2T U V$0%4"2 $W 1$2(502"% ;&%05&0%( X-+($5+(,Y =ZD XDHHDY >?>[>Z= HaH

;46/&/ aM >#"&/%)4 )#(/%'4()"# 1/(O//# (6/ #)(%"9+*# ,+,(/& '#2 (6/&!

Q!AR 1"#2M

BT ;'%' (& "2T U V$0%4"2 $W 1$2(502"% ;&%05&0%( X-+($5+(,Y =ZD XDHHDY >?>[>Z= HaG

U)3M HcM A,/52"8"(/#()'* $"% (6/ (O" 2)',(/%/"),"&/%, "$ B_SPC VHc<HJXM

B'1*/ ^

!"&8'%),"# "$ (6/ /#/%3/()4 .'*5/, %/,5*()#3 $%"& (6/ (O" ,(52)/, '#2 (6/ 8",)()"#, "$ (6/ 4%)()4'* 8")#(, "1(')#/2 1+ (6/ (O" &/(6"2,

@/#N"* C"4?/#1'5/% VDJ<D^X S'%%)/% Q?F &"*"HR @'8 1/(O//# &)#)&' Q?F &"*"HR S'%%)/% Q?F &"*"HR @'8 1/(O//# &)#)&' Q?F &"*"HR AC_Yml HZ E HHMa E B_NPC HJ Z DEMG G B_SPC 5'3 ZD W DE W B_SPC &%"43 Za W D^MG W @/#N"* C"4?/#1'5/% VDJ<D^X

N)#)&' N'9)&' N)#)&' N'9)&'

$HQ2/3R $GQ2/3R $DQ2/3R $ZQ2/3R $HQ2/3R $GQ2/3R $DQ2/3R $ZQ2/3R

AC_Yml aa G^D D HaE bE G^E E HaE

B_NPC bZ GaG Q"HJIZcR' QHZ^WGEbR' bc G^J ^ Hac

B_SPC 5'3 HEE W Q"H^aIGHR' W aG W DGZ W

B_SPC &%"43 W GbH W QHZWGEHR' W G^G W HcE

854?/%)#3 25%)#3 (6/ 8,/52"%"('()"# ), #/3*/4(/2M B6/ S"*([&'## O/)36(/2 !06$44 '%/ 4'*45*'(/2 '44"%2)#3 ("7 !"Y" " & ' R&4",G"'_/98!"a'$`-# & ' /98!"a'$`-# O6/%/ a' ), (6/ 8,/52"8"(/#()'* .'*5/ $"% (6/ '(6 4"#$"%&'()"#M B6), &/(6"2 6', 1//# '88*)/2 (" (6/ $"5% 8+%%"*)2)#/0:0"9+* %'2)4'*, QU)3,M HZ '#2 HcR '#2 (6/ %/,5*(, O/%/ 4"&8'%/2 (" (6/ &"*/45*'% &/46'#)4, ,(52+M

S"(6 &/(6"2, 8%".)2/2 ,)&)*'% %/,5*(, QU)3,M HEWHc

'#2 B'1*/ ^RM U"% AC_Yml< (6/ &)#)&' 8",)()"#, '%/ ./%+ 4*",/ '#2 (6/ (O" 4'*45*'(/2 1'%%)/%, O/%/ )# 3""2 '3%//&/#(M U"% B_NPC< (6/ &)#)&' '%/ *"4'(/2 '%"5#2 (6/ ,'&/ 8",)()"#, 15( O/ $"5#2 ' *'%3/ 2)$$/%0 /#4/ 1/(O//# (6/ 1'%%)/% .'*5/,M h#*)?/ (6/ C"4?/#0 1'5/%k, '88%"'46< "5% &"*/45*'% &/46'#)4, &/(6"2 ('?/, )#(" '44"5#( (6/ .'%)'()"# "$ (6/ 854?/%)#3 '&8*)(52/ 25%)#3 (6/ %)#3 &"()"#M U"% (6/ &'9)&5& .'*5/ "$ (6/ ,(/%)4 /#/%3+< O/ $"5#2 (6'( (6/ 854?/%)#3 '&8*)(52/ .'*5/ O', 4*",/ (" [/%" Q8*'#'% 4"#$"%&'0 ()"#R QU)3M HDRM L)(6 1"(6 &/(6"2,< O/ $"5#2 ' 5#)]5/ &)#)&5& $"% /'46 2)',(/%/"),"&/% "$ B_SPC QU)3,M HE< HH '#2 HcRM B6/ &)#)&' 8",)()"#, "$ /'46 2)',(/%0 /"),"&/% '%/ 4*",/7 HEE .,M aG# $"% B_SPC 5'3 '#2 GbH .,M G^G# $"% B_SPC &%"43 QB'1*/ ^RM B6/ @/#N"* 1'%%)/% .'*5/, '%/ "./%/,()&'(/2M K/./%(6/*/,,< (6/ @/#N"* QHMHR '#2 (6/ C"4?/%1'5/%k, QHMGR 1'%%)/% 6/)36( %'()" Q&%"43d5'3R '%/ )# 3""2 '3%//&/#(M

BT ;'%' (& "2T U V$0%4"2 $W 1$2(502"% ;&%05&0%( X-+($5+(,Y =ZD XDHHDY >?>[>Z= HaD

;46/&/ bM B'1*/ a !06$44 "$ AC_Yml 4'*45*'(/2 1+ )#(/3%'()"# "# (6/ O6"*/ 8,/50 2"%"('()"#'* 45%./ @/#N"* P98 VDJ<D^X !"!H" Q@R ^MH ^MD !"!G" Q@R ^ME ^ME !"!D" Q@R ^MH ^MJ !"!Z" Q@R ^MH JMa N/'# .'*5/ Q@R ^MH JMb B'1*/ HE

!"#$"%&/%, %/,5*()#3 $%"& (6/ ,)&8*)-/2 4"#$"%&'()"#'* '#'*+,),

!"#$"%&/% H !"#$"%&/% G

B+8/ J,(/%)4Q?F &"*"HR $ Q2/3MR /Q>j R B+8/ J,(/%)4Q?F &"*"HR $ Q2/3MR /Q>j R

AC_Yml ZBD ^Z GJb EMDZ DBZ ^Z aZ EMDZ

B_NPC ZBD a^ GJ^ EMDZ DBZ bD bb EMDD

B_SPC 5'3 DBZ HHZ bG EMDD W W W W

B_SPC &%"43 ZBD HEb G^J EMDD W W W W

B'1*/ b !06$44 "$ (6/ 86",86"%+*'(/2 8+%%"*)2)#/0:0"9+* %'2)4'*, 4'*45*'(/2 1+ )#(/3%'()"# "# (6/ O6"*/ 8,/52"%"('()"#'* 45%./ B_NPC B_SPC 5'3 B_SPC &%"43 @/#N"* P98 VDbX @/#N"* P98 VDbX @/#N"* P98 VDbX !"!H" Q@R ^MG ^MG ZMD DME bMc aMH !"!G" Q@R cMJ cMJ bMH bMD DMc cMG

!"!D" Q@R ^MG cME ^Mc aMJ aMD ZMH

ETCT cOK(%b4( 5$0K2'4M 5$43&"4& 5"2502"&'$4

U%"& (6/ 8,/52"%"('()"#'* 45%./, QU)3,M HG '#2 HDR< O/ 4'*45*'(/2 (6/ S"*([&'## O/)36(/2 !06$44 "$ /'46 !0Y`#54*/5, O)(6 #"# [/%" ,8)# Q;46/&/ bR '44"%20 )#3 ("7 !"Y" " %DJE

'"HK'"Y

' '#2 4"&8'%/2 (6/& (" (6/ /98/%)&/#('* .'*5/, QB'1*/, a '#2 bRM U"% AC_Yml< @/#N"* 8%".)2/2 ' 3""2 /,()&'()"# "$ (6/ !06$44< 6"O/./%< (6/ .'*5/, "1(')#/2 $"% (6/ !086",86"%+0 *'(/2 #)(%"9)2/, O/%/ #"( )# '3%//&/#( O)(6 /98/%)0 &/#('* 2'(' QB'1*/ bRM >, )( O)** 1/ ,6"O# )# (6/ #/9( ,/4()"#< @/#N"* 4'*45*'()"#, O/%/ ,'(),$+)#3 (" 2/(/%0 &)#/ (6/ &)#)&' "# (6/ 8,/52"%"('()"#'* 8'(6M g"O/./%< (6/ 8,/52"%"('()"#'* 1'%%)/%, O/%/ 5#2/%/,0 ()&'(/2 (65, ,533/,()#3 (6'( (6/ O/)36( "$ ,"&/ 4"#$"%&'()"#, ), "./%/,()&'(/2 (" 4'*45*'(/ (6/ !0 6$44M B" 46/4? (6), 8")#(< O/ 2/4)2/2 (" 4'*45*'(/ (6/ !06$44 4"#,)2/%)#3 "#*+ (O" 4"#$"%&/%, $"% AC_Yml '#2 B_NPC '#2 "#/ 4"#$"%&/% $"% /'46 2)',(/%/"),"&/% "$ B_SPCM

ET=T ;',K2'b() 5$4W$%,"&'$4"2 "4"2O3'3

B6/ GE )2/'* 4"#$"%&'()"#,!$ " E" Ha" DJ" ^" DZG## O)(6 '# '%1)(%'%+ 854?/%)#3 '&8*)(52/ /" E!Z "> '%/ '5("&'()4'**+ 15)*( 1+ (6/ @/#N"* ,"$(O'%/M P'46 4"#$"%&'()"# ), (6/# $5**+ "8()&)[/2 '#2 4*',,)-/2 QDBZ< DP<nRM >$(/% %/&".)#3 (6/ %/25#2'#4)/,< (6/ !0 6$44 4'*45*'()"#, O/%/ 2"#/ "# (6/ &",( ,('1*/ 4"#$"%0 &/%, "#*+ QB'1*/ HERM B6/ !06$44 4'*45*'(/2 $%"& "#/ Q$"% B_SPC 5'3 '#2 &%"43R "% (O" Q$"% B_NPC '#2 AC_YmlR 4"#$"%0 &/%, '%/ )# &546 1/((/% '3%//&/#( O)(6 (6/ /98/%)0 &/#('* .'*5/, QB'1*/, HH '#2 HGRM B6/,/ %/,5*(, 4"#-%& (6'( (6/ 8%"1*/& /#4"5#(/%/2 O)(6 (6/ !0 6$44 4'*45*'(/2 $%"& (6/ DJE 4"#$"%&'()"#, O', 25/ (" 5#2/%/,()&'(/2 8,/52"%"('()"#'* 1'%%)/%,M

7) 8,+'6.#/,+

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i"% 4"#$"%&/% /9),(,M !"&8'%/2 O)(6 (6/ %/,5*(, "1(')#/2 1+ (6/ 8,/52"8"(/#()'* &/(6"2< @/#N"* $')*/2 (" 3)./ ' 3""2 ]5'#()('()./ /,()&'()"# "$ 1'%%)/% 6/)36(, $"% (6/ 8,/52"%"('()"# "$ ,"&/ -./0&/&1/%/2 %)#3,M g"O/./%< (6/ %/*'()./ .'*5/, 3)./ ' ]5'*)('()./ )2/' "$ (6/ ,(/%)4 ,(%')# .'%)'()"# 25%)#3 (6/ 8,/52"%0 "('()"# '#2 Q"%R (6/ )#./%,)"#M

B6/ &')# '2.'#('3/ "$ (6), &"*/45*'% &/46'#)4, '88%"'46 ), )(, 8%/2)4()./ 46'%'4(/% ,)#4/ )( '**"O, (" 2/,)3# #/O #)(%"9)2/, O)(6 ' 2/,)%/2 4"#$"%&'()"#'* 1/6'.)"% '#2 ' 46'%'4(/%),()4 P;C ,8/4(%5&M

B6/ 4"#$"%&'()"#, "$ 8+%%"*)2)#/0:0"9+* %'2)4'*, '%/ /,,/#()'**+ 3"./%#/2 1+ ,(/%)4 )#(/%'4()"#, '#2 &"*/45*'% &/46'#)4, ), ' $',( '#2 /$-4)/#( &/(6"2 (" &"2/* ,546 )#(/%'4()"#,M N"%/"./%< (6/ ,)&8*)-/2 4"#$"%&'()"#'*

BT ;'%' (& "2T U V$0%4"2 $W 1$2(502"% ;&%05&0%( X-+($5+(,Y =ZD XDHHDY >?>[>Z= HaZ

B'1*/ HH

!06$44 "$ AC_Yml 4'*45*'(/2 $%"&DBZ'#2ZBD4"#$"%&/%, @/#N"* P98 VDJ<D^X !"!H" Q@R ^MD ^MD !"!G" Q@R JMb ^ME !"!D" Q@R ^Mc ^MJ !"!Z" Q@R JMb JMa N/'# .'*5/ Q@R ^MG JMb B'1*/ HG

!06$44 4'*45*'(/2 $%"& /)(6/% (O" %'8)2*+ /946'#3)#3 4"#$"%&/%, QB_NPCR "% ' ,)#3*/ 4"#$"%&/% QB_SPC 5'3< B_SPC &%"43R

B_NPC B_SPC 5'3 B_SPC &%"43

@/#N"* P98 VDbX @/#N"* P98 VDbX @/#N"* P98 VDbX

!"!H" Q@R aMD ^MG cMZ DME aMa aMH

!"!G" Q@R JMH cMJ aM^ bMD cMG cMG

!"!D" Q@R cMa cME aMc aMJ JMD ZMH

'#'*+,), *)&)(/2 (" (6/ &",( ,('1*/ 4"#$"%&/%,< (5%#/2 "5( (" 1/ &"%/ /$-4)/#( (6'# (6/ 4'*45*'()"# "./% (6/ $5** 8,/52"%"('()"#'* ,5%$'4/M \( &'+ 1/ (65, '88*)/2 (" -./0&/&1/%/2 %)#3, 1/'%)#3 &'#+ 15*?+ ,51,()(5/#(, O)(6"5( ' 653/ )#4%/',/ "$ (6/ 4'*45*'()"# ()&/M 5292%2+'2# VHX lM:M S/%*)#/% QP2MR< ;8)# l'1/**)#3< B6/"%+ '#2 >88*)4'()"#,< ."*M H< >4'2/&)4 A%/,,< K/O m"%?< Hb^JM

VGX lM:M S/%*)#/% QP2MR< ;8)# l'1/**)#3< B6/"%+ '#2 >88*)4'()"#,< ."*M G< >4'2/&)4 A%/,,< K/O m"%?< Hb^bM

VDX KM o"46/%3)#,?+< gMNM ;O'%([< K)(%"9)2/ ;8)# l'1/*,< !C! A%/,,< S"4' C'("#< HbbcM VZX SM !6)"#< >M !'8)"&"#(< FM l'i[/p%"O)4[< >4(' !%+,(M S Ga QHb^GR JHaM VcX BM>M _*,['?< NMFM @%'1"O,?)< oM @O"[2[)#,?)< >4(' !%+,(M ! Zb QHbbDR H^GGM

VJX BM>M _*,['?< AMgM ;"14[+#,?)< >M S%["["O,?)< NMFM @%'1"O0 ,?)< oM @O"[2[)#,?)< >4(' !%+,(M ! cH QHbbcR HGHM

V^X CM S/#',,)< UM B'22/)< lM @%/4)< lM N'%46/(()< @M:M >#2%//(()< @M S"4/**)< AM ;3'%'1"(("< FM !6/&M ;"4M< A/%?)# B%'#,M G QHbaER ^aJM

VaX FM!M>M S"/+/#,< @MFM o%53/%< >4(' !%+,(M S GJ QHb^ER JJaM VbX >M @%'#2< AM C/+< >4(' !%+,(M S Dc QHb^bR GHZbM

VHEX LM B5%*/+< UMAM S"/%< >4(' !%+,(M S Ga QHb^GR HJZHM VHHX >MCM U"%%/,(/%< )#7 gM U),6/%< oMgM g/**O/3/ QP2,MR< l'#2"*(WS"q%#0

,(/)# N'3#/()4 A%"8/%()/, "$ U%// C'2)4'*,< l'#2"*(WS"q%#,(/)# N'3#/()4 A%"8/%()/, "$ U%// C'2)4'*,Hb^b< 88M DaJWZZG A'%( !HM VHGX >MCM U"%%/,(/%< )#7 gM U),6/%< oMgM g/**O/3/ QP2,MR< l'#2"*(W S"q%#,(/)# N'3#/()4 A%"8/%()/, "$ U%// C'2)4'*,< ."*M H^< ;8%)#3/%< S/%*)#< Hbab< 88M HGJWHa^M

VHDX TM S'%"#/< >M S/#4)#)< NM !",,)< >M :) N'((/"< NM N'((/,)#)< UM B"(()< FM >&M !6/&M ;"4M HGE QHbbaR ^EJbM

VHZX oM ;'?'?)1'%'< gM o'O'&5%'< BM K'3'('< FM C/#< NM g)%"('< oM ;6)&'['?)< BM !65&'#< S5**M !6/&M ;"4M F8# J^ QHbbZR G^JaM VHcX UM T)*'< AM B"%2"< :M ;)%)< @M A/r8/< U%// C'2M C/,M !"&&5#M

Hb QHbbDR ;H^W;GGM

VHJX >M N/%4)/%< mM S/%46'2,?+< :M S'2%52)#< ;M A)/(%)< AM B"%2"< B/(%'6/2%"# l/((M DG QHbbHR GHGcM

VH^X FMNM B%"#46/(< >M C)44'< UM S'%1'*'(0C/+< NM @/"$$%"+< !'%1"6+2%M C/,M GHZ QHbbHR GDcM

VHaX :M !%/&/%< FM>M A"8*/< FM >&M !6/&M ;"4M b^ QHb^cR HDcaM VHbX :M !%/&/%< FM;M S)#?*/+< FM>M A"8*/< FM >&M !6/&M ;"4M ba

QHb^JR JaDJM

VGEX PM !"%(/[< FM l''#/< FM N"*M ;(%54(M DZJ QHbbcR ZHM

VGHX lM !'%1'**/)%'< \M A/p%/[0F5,(/< FM !6/&M ;"4M A/%?)# B%'#,M G QHbbaR HDDbM

VGGX !M >*("#'< NM ;5#2'%'*)#3'&< FM >&M !6/&M ;"4M bZ QHb^GR aGEcM VGDX gMFM @/),/< !M >*("#'< !M C"&/%,< B/(%'6/2%"# l/((M Hc QHbJ^R

HDaDM

VGZX :M !%/&/%< FM>M A"8*/< FM >&M !6/&M ;"4M b^ QHb^cR HDcZM VGcX gM P,,/#< :M !%/&/%< >4(' !%+,(M S ZE QHbaZR ZHaM VGJX :M !%/&/%< FM A6+,M !6/&M bZ QHbbER ccEGM VG^X >M:M U%/#46< TM B%'#< S)"8"*+&/%, Gb QHbbER HcbbM

VGaX LM:M !"%#/**< NMAM g'< mM ;5#< AM>M o"**&'#< FM !"&85(M !6/&M H^ QHbbJR HcZHM

VGbX LM !5)< UM l)< KMlM >**)#3/%< FM >&M !6/&M ;"4M HHc QHbbDR GbZDM VDEX NMBM @"%2"#< BMlM l"O'%+< !MNM g'2'2< FM >&M !6/&M ;"4M

HGH QHbbbR bJaGM

VDHX FM @%5['< FM o"4'< ;M A/p%/[< >M \&1/%(+< FM N"*M ;(%54(M QB6/"0 46/&R ZGZ QHbbaR GJbM

VDGX ;M A/p%/[< >M \&1/%(+< ;MSM P#3/*,/#< FM @%5['< oM N'[/'5< FM F)&/#/[0S'%1/%"< >M A"./2'< FM0UM P,8)#",'< SMAM .'# P+4?< @M F"6#,"#< >M:M U%/#46< NMlM o"5O)i[/%< AM:MFM @%""(/#5),< >M S/%#'%2)< lM C')&"#2)< gM ;/#2/%"O)([< TM :5%)/%< @M T/%3"(/#< oM C',&5,,/#< !'%1"6+2%M C/,M DHZ QHbbaR HZHM VDDX FM C''8< FMgM .'# S""&< gM!M .'# l)/,6"5(< !M>M@M g'',#""(<

FM >&M !6/&M ;"4M HHE QHbaaR G^DJM

VDZX @M A/r8/< :M ;)%)< ;(52M A6+,M B6/"%M !6/&M HH QHbbER ZHHM VDcX KMlM >**)#3/%< FM >&M !6/&M ;"4M bb QHb^^R ;aHG^M VDJX >M C"4?/#1'5/%< NM @+"q%< _M g'#?".,[?+< oM g)2/3< )#7 NM!MCM

;+&"#, QP2MR< P*/4(%"# ;8)# C/,"#'#4/< ."*M HH>< B6/ C"+'* ;"4)/(+ "$ !6/&),(%+< !'&1%)23/ QhoR< Hbaa< 8M HZcM VD^X >M C"4?/#1'5/%< lM o"%/4[< oM g)2/3< FM !6/&M ;"4M< A/%?)#

B%'#,M G QHbbDR GHZbM

VDaX !M g/**/%< gMNM N'4 !"##/**< FM !6/&M A6+,M DG QHbJER HcDcM VDbX lM :/&1%"O,?)< FM0AM U)#/(< !M U%/pi'.)**/< UM l/ N")3#/< CM N'5%)#< >M N/%4)/%< AM A'3/,< AM ;()8'< AM B"%2"< U%// C'2M C/,M !"&&5#M Hb QHbbDR ;GDM

VZEX FMPM o)*8'(%)4?< oM A)([/%< CM ;8)([/%< FM >&M !6/&M ;"4M Jb QHbZ^R GZaDM

VZHX FMCM :5%)3< :MLM L/%([< FM !6/&M A6+,M Zb QHbJaR GHHaM VZGX lM>M !'%%/)%'< @MFM F)'#3< LM A/%,"#< FMKM L)**),< FM !6/&M

A6+,M cJ QHb^GR HZZEM

VZDX lMPM S'5&'#< FM l''#/< FM A6+,M !6/&M bG QHbaaR HEZEM VZZX FM !6""< FM l''#/< FM !6/&M A6+,M HEH QHbbZR G^^GM VZcX CMlM C",',< !M !""8/%< FM l''#/< FM A6+,M !6/&M bZ QHbbER HaDEM VZJX \M o"&'%"&)< FMNMFM B%"#46/(< FM A6+,M !6/&M bb QHbbcR

HEGHDM

VZ^X FMFMAM ;(/O'%(< FM !"&85(M !6/&M HE QHbabR GEbM

VZaX >&8'4 JMcc<!Hbba ;/&)46/&< \#4M< A_ S_Y HJZb< ;6'O0 #//< o; JJGGGM

VZbX NMFM U%),46< @MLM B%54?,< gMSM ;46*/3/*< AMNMLM @)**< SM@M F"6#,"#< NM>M C"11< FMCM !6//,/&'#< BM o/)(6< @M>M A/(/%,,"#< FM>M N"#(3"&/%+< oM C'36'.'46'%)< NM>M >*0l'6'&< TM@M s'?%[/O,?)< FMTM _%()[< FMSM U"%/,&'#< FM !)"*"O,?)< SMSM ;(/$'0 #".< >M K'#'+'??'%'< NM !6'**'4)&1/< !MmM A/#3< AM mM >+'*'< LM !6/#< NMLM L"#3< FMlM >#2%/,< PM;M C/8*"3*/< CM @"&8/%(,< CMlM N'%()#< :MFM U"9< FM;M S)#?*/+< :MFM :/$%//,< FM S'?/%< FMAM ;(/O'%(< NM g/'20@"%2"#< !M @"#['*/[< FM>M A"8*/< !"#$' $%"&bZ< @'5,,)'# \#4M< A)((,15%36< HbbcM VcEX PM F5'%),()< @M !5/.',< B/(%'6/2%"# Za QHbbGR cEHbM VcHX TM@M;M S"9< g/(/%"4+4*/, DH QHbbER HHc^M VcGX AM :/,*"#346'&8,< ;(/%/"/*/4(%"#)4 P$$/4(, )# _%3'#)4 !6/&0 ),(%+< A/%3'&"# A%/,,< _9$"%2< HbaD< 88M ZWcDM

VcDX hM ;'*[#/%< FM _%3M !6/&M JE QHbbcR baJM

VcZX FM o'([6/#2*/%< \M C)#3/*< CM o'%'&'#< gM s'6/%< PM S%/5/%< FM !6/&M ;"4M< A/%?)# B%'#,M G QHbb^R DZHWDZbM

VccX UMgM >**/#< _M o/##'%2< D: ,/'%46 '#2 %/,/'%46 5,)#3 (6/ !'&1%)23/ ,(%54(5%'* 2'('1',/< !6/&M :/,M >5("&M K/O, a QHbbDR DHM

Large Phosphorus Hyperfine Coupling as a Sensitive Tool for Studying Molecular

Dynamics: ESR and Molecular Mechanics Studies of Ring Interconversion in the

cis-2,5-Diphosphoryl-2,5-dimethyl-pyrrolidinoxyl Radical

Antal Rockenbauer,Anouk Gaudel-Siri,Didier Siri,Yves Berchadsky,§Franc¸ois Le Moigne,§

Gilles Olive,§and Paul Tordo*

Chemical Research Center, Institute of Chemistry H-1075 Budapest, Pusztaszeri 59, Hungary,

Laboratoire de Chimie The´orique et Mode´lisation Mole´culaire, UMR 6517, CNRS-UniVersite´s d’Aix-Marseille I et III, Case D42, 13397 Marseille, Ce´dex 20, France, and Laboratoire Structure et Re´actiVite´ des Espe`ces Paramagne´tiques, UMR 6517, CNRS-UniVersite´s d’Aix-Marseille I et III, Case 521, 13397 Marseille, Ce´dex 20, France

ReceiVed: June 5, 2002; In Final Form: January 20, 2003

ESR spectra of cis- and trans-β-diphosphorylated pyrrolidine-N-oxyl radicals, c-1 and t-1, were studied in liquid and frozen solution. The expected 1:2:1 triplet (aP(2)) of the 1:1:1 triplet (aN) was observed for t-1; however, for c-1, the inner lines of the 1:2:1 triplet showed a dramatic broadening characteristic of chemical exchange between two equivalent conformations. Owing to the large difference in the hyperfine splitting constants (hfsc) of the exchanging phosphorus (∆aP ≈ 21 G), the coalescence temperature was unusually high (193 K, in n-pentane), and the potential barrier for ring interconversion (10.5 kJ mol-1) was easily obtained from the temperature dependence of the exchange rate. This value was in very good agreement with the value obtained for an empirical pseudorotational potential (11 kJ mol-1) that was adjusted to fit the temperature dependence of the phosphorus hfsc. For c-1, molecular mechanics calculations gave similar characteristics for the pseudorotational potential and indicated the existence of two identical minima with distorted geometries lying between3T4and3E or4T3and E3. For t-1, only the3T4conformer was found to be significantly populated. Frozen solution spectra showed that the phosphorus hfsc anisotropy is higher when the C-P bond is pseudoaxial; this result can be explained by a geometry-dependent delocalization of the unpaired electron into the phosphorus 3p orbitals.

Introduction

Because of the biological importance of various five-membered rings such as those of ribose rings in nucleic acids1

and proline residues in peptides and proteins,2 there is still considerable interest in determining the conformational states of five-membered rings. Pyrrolidine-N-oxyl radicals (Scheme 1) form an important class of five-membered ring radicals. If their dismutation is prevented by the absence of hydrogens on the R carbons, then most of these radicals are chemically stable, and different approaches have been developed to investigate their conformational behavior.3,4

The conformers of five-membered rings can be close to either envelope (E) or twist (T) geometries (Figure 1). Conversion among the various conformers is usually thought to occur through pseudorotation. Spectroscopic techniques often fail to give reliable information on the heights and positions of barriers to interconversion, except for few simple molecules when the microwave technique is applicable.5 As compared to six-membered rings containing six σ bonds (sp3carbon or nitrogen atoms) where energetically well-separated (∆G0 is ca. 20 kJ mol-1) and slowly interconverting (the interconversion

fre-quency is less than 5 × 108 s-1 below room temperature) conformers exist,6the analogous five-membered rings are rather flexible, and interconversion is fast. (∆G0does not exceed 10 kJ mol-1, and the interconversion frequency is larger than 7× 109s-1 above 200 K.7,8a) This difference is evident in ESR spectroscopy studies where line-width alternation due to chemi-cal exchange is often observed in the spectra of radichemi-cals centered on a six-membered ring. However, for the five-membered ring analogues, such phenomena were detected only in a few cases using the low-temperature matrix technique.8For five-membered ring radicals, the lack of line-width alternation is caused by the complete averaging of coupling constants due to the fast pseudorotation.

Line broadening resulting from chemical exchange depends on the square of the differences in the coupling constants for * Corresponding author. E-mail: tordo@srepir1.univ-mrs.fr. Tel: 33 4

91 632 851.

†Institute of Chemistry.

‡Laboratoire de Chimie The´orique et Mode´lisation Mole´culaire, CNRS-Universite´s d’Aix-Marseille I et III.

§Laboratoire Structure et Re´activite´ des Espe`ces Paramagne´tiques, CNRS-Universite´s d’Aix-Marseille I et III.

SCHEME 1

3851

J. Phys. Chem. A 2003, 107, 3851-3857

10.1021/jp0213351 CCC: $25.00 © 2003 American Chemical Society Published on Web 04/11/2003

interconverting sites, and since β-phosphorus couplings are typically two or three times larger than the respective β-hydro-gen couplings, the presence of a β-31P atom in a free radical should enhance the chance to observe chemical exchange.

In our earlier studies, dramatic line-broadening effects were indeed observed on the ESR spectra of peroxyl radical adducts of 2-diethoxyphosphoryl-2-methyl-3,4-dihydro-2H-pyrrole-1-oxide (DEPMPO)9a,b as well as on those of geminal diphos-phoryl-substituted pyrrolidinoxyl radicals.9c Interconversion between conformers with different ring geometries resulting from hindered rotation around the O-OR bond in the first case or the C-P bond in the second case9ccan explain the observed line broadening. However, in both cases, the barrier for ring inversion does not represent the major contribution to the total barrier for interconversion, and thus the rate of ring inversion is not available from ESR experiments.

Because of the preference of the pyrrolidinoxyl radicals for

3T4 and 4T3 twist conformations3 and the preference of the diethoxyphosphoryl group for axial geometry,3cno ring inter-conversion was observed for trans-2,5-diethoxy-phosphoryl-2,5-dimethyl-pyrrolidinoxyl nitroxide t-1 (Scheme 1, Figure 2). However, for cis-2,5-diethoxyphosphoryl-2,5-dimethyl-pyrro-lidinoxyl nitroxide c-1 (Scheme 1), one phosphoryl substituent occupies the preferred axial geometry, and the second is forced to the less stable equatorial orientation. As a consequence, a double minimum is expected in the pseudorotational itinerary of the pyrrolidinoxyl ring.

In the present paper, we give a complete analysis of the ESR spectra of c-1 recorded over a large temperature range. To obtain reliable calculated data, liquid and frozen solution spectra were simulated by an automatic parameter-fitting procedure.10 The study of the influence of temperature on the interconversion rate yielded the thermodynamic parameters of the process. We also considered the influence of solvent molecules on the chemical exchange. Moreover, in frozen solution, where dif-ferent ring geometries can be fixed by solvation, we examined the possibility of phase transition due to molecular rearrange-ments in the coordination sphere.

Finally, to have a complete description of the pseudorotational itinerary, conformational analysis of t-1 and c-1 was performed

using molecular mechanics calculations. In this approach, the influence of rotation around the C-P bonds was considered.

Results and Discussion

ESR Spectra. The ESR spectrum of t-1 consisted of a large

1:2:1 triplet due to coupling with two equivalent phosphorus nuclei, each line being further split into the 1:1:1 triplet of14N. As shown in Figure 2, no chemical exchange was observed in the temperature range between 193 and 313 K.9c

At elevated temperature, the ESR spectra of t-1 and c-1 are similar. However, for the cis isomer, the inner lines of the 1:2:1 triplet showed a dramatic broadening that is characteristic of a chemical exchange (Figure 3). A decrease in the temperature increased the broadening of the inner lines, whereas lines in the wings remained sharp. Inner and outer lines had nearly identical amplitudes at 253 K, and coalescence was achieved at 193 K. Below this temperature, new lines evolved in the center of the spectrum, indicating the presence of frozen conformers.

Figure 1. Usual representation of the pseudorotation of five-membered

rings. Figure 2. Experimental and calculated ESR spectra for t-1: 193 K

(top) and 313 K (bottom).

Figure 3. Experimental and calculated ESR spectra for c-1 at different

temperatures.