Teeninga, Hermannus

English

This thesis describes an investigation of the electronic structure of sulfonamidyl radicals (R1SO2NR2) and some structurally related carboxamidyl radicals (R1C(0)NR2). Both types of radicals have been invoked as intermediates in several chemical reactions. The present work originates from our interest in the influence of the sulfonyl group on a nitrogen-free radical center in comparison with that of the carbonyl group. ... Zie: Summar

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   University of GroningenThe electronic structure of sulfonamidyl radicals. An ESR spectroscopic and ab-initio MOstudy of sulfonamidyl and some carboxamidyl radicalsTeeninga, HermannusIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:1983Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Teeninga, H. (1983). The electronic structure of sulfonamidyl radicals. An ESR spectroscopic and ab-initioMO study of sulfonamidyl and some carboxamidyl radicals. s.n.CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 20-06-2022S U M M A R YTh is  t hes i s  desc r i bes  an  i nves t i ga t i on  o f  t he  e lec t ron i c  s t ruc tu re  o fsu l f onamidy l  r ad i ca l s  (n rs0 rNRr )  and  some s t ruc tu ra l l y  re la ted  ca rboxam ' i dy lrad i ca l s  (R rC(0 ) f l n2 ) .  eo t f r  t ypÀs  o f  r ad i ca l s  have  been  i nvoked  as  i n te rmed i -a tes  i n  seve ra l  chemica l  r eac t i ons .  The  p resen t  wo rk  o r i g i na tes  f r om ou r  i n -t e res t  i n  t he  i n f l uence  o f  t he  su l f ony l  g roup  on  a  n i t r ogen - f ree  rad i ca l  cen -ter  in  compar ison wi th that  of  the carbonyl  group.Rrso2- i -  R2There fo re ,  a  l a rge  va r i e t y  o f  am idy l  r ad i ca l s  o f  t he  t ypes  1  -  4  have  beengene ra ted  and  s tud ied  by  ESR spec t roscopy .  These  ra the r  sho r t - l i ved  am idy l  r a -d i ca l s  we re  p roduced  by  pho to l ys i s  o f  ca re fu l l y  degassed  so lu t i ons  o f  t he  co r -respond ing  N-b romo  compounds  (o r ,  i n  some  cases ,  t he  N -ch lo ro  compounds )  i n i n -asor, fl .R I S 0 2 - N - 0 R 2  C n  - N .  Z - C - N - R, . -- / -  \n = 1 , 2  Z : R 1 R 2 N - , R 1 0 -? 1l.xI  x ' ,e . g .  R 1 s o 2 N - R z 4X = B r ,  C IR SO N-RL 2er t  so ' l ven ts ,  such  as  t r i ch lo ro f l uo rome thane ,  d i rec t l y  i n  t he  cav i t y  o f  t he  ESRspec t rome te r  a t  l ow  tempera tu res .  I n  t he  Tab le  t he  ESR resu l t s  f o r  I  - 4  havebeen  summar i zed  toge the r  w i t h  some  l i t e ra tu re  da ta  f o r  no rma l  N -a l ky l ca rboxami -dy ls  ( f rom the work of  Ingold ef .  a .L) .Fur thermore,  ab- íwí Í io  M0 calculat ions have been carr ied out  on model  sys-tems  fo r  su l f on -  and  ca rboxamidy l s .  The  open -she l l  r es t r i c ted  Ha r t ree -Fock(RHF)  ca l cu la t i ons  have  been  pe r fo rmed  ma in l y  by  us ing  the  "doub le  ze ta "  bas i so f  Roos  and  S iegbahn .Chap Í .e ' t  Í  con ta ins  an  i n t roduc t i on  and  su rvey  o f  t he  l i t e ra tu re ,  w i t h  pa r -t i c u l a r  e m p h a s i s  o n  a m i n y l s  ( R r N R 2 )  a n d  c a r b o x a m i d y l s .  T h e  d i s c u s s i o n  i s  m a i n l y1 5 3TABLE: Observed ni t rogen hfscrs and g values for  d i f ferent  types of  sul fon-and carboxamidyls.r ad i ca l An (gauss) g valuec luded  tha t  N -a l  koxYsu l 'v i ve  l ong  enough  i n  so l ts tab le  t ha t  comP l i ca tedChapÍen 4 recordsme t r y  op t im iza t i ons  hav rand : )  o f  N-methyl formatca l  s .  The  fo l  I  ow i  ng  op t1  (15d  -  29d )2 (34d - 49d)3  (55d  -  65d )4  (Z  =  R -  R^N- ,  78d  -  82d )L Z4  ( Z =  R . O ,  8 5 d  -  8 7 d )I -acycl ic  carboxanidyls*(R1c (o ) rïRz )cycl ic  carboxanidyl(5-nenbered r ing,  59d)1 2 . 9  -  1 3 . 51 1 . 2  -  1 1 . 87 2 . 4  -  t 3 . 4L 4 . S1 4 . 0  -  1 5 . 6À1,4 -  16"17 .2ca" 2.OO44ce 2 .OO50ca" 2.OO45c a , 2 . O O 4 72 .0046 -  2 .  0053h2 . O O 4 4  -  2 . 0 0 5 5 -2 .  0 0 6 3a . _ .  b- -  Taken  f r om l i t e ra tu re  daEa .  -  Depend Íng  on  t he  bu l k  o f  R " .centered on the questjon how information about eon{igunaíLon and con(onmaÍiono f  f r ee  rad i ca l s  can  be  deduced  f rom ESR-spec t ra l  da ta .  I n  add i t i on ,  t he  p re -requis i tes for  the ESR-spectroscopic detect ion of  f ree radjcals  of  I  ow pelL6iÁ-tence are out l ined.In Chctptzn 2 a deta i led study of  N-alky ' lsu l fonamidyls  1 is  presented.  Infac t ,  t h i s  s tudy  i s  an  ex tens ion  o f  t he  wo rk  o f  Zomer  and  Engbe r t s  on  N- l -bu -t y l su l f onamidy l  r ad i ca l s .  As  compared  w i th  ca rboxamidy l s ,  su l f onamidy l s  a resomewha t  more  pe rs i s ten t .  The  n i t r ogen -hype r f i ne  coup l i ng  cons tan ts  (h f sc ' s )and g values (Tab1e) are character is t ic  for  a r f  eLze. t t tonie gnound  ̂íaÍe,  inwh ich  the  odd  e lec t ron  res ides  i n  an  N-2p  o rb i t a l  pe rpend i cu la r  t o  t he  SNCp 1 a n e .  S u b s t i t u e n t  e f f e c t s  o n  t h e  A *  v a l u e s  a r e  s m a l l  a n d  s u g g e s t  l j t t l e  o rno  sp in  de loca l i za t i on  on to  t he  su l f ony l  g roup .  The  tempera tu re  dependence  o fthe A;1U parameter  of  several  R1S02NCH2R2 and RrS0rNCHMe, radicals  has a lsobeen measured.Clnapten 3 conta ins an ESR study of  N-alkoxysul fonamidyl  radicals  2.  TheESR da ta  (Tab1e )  p rov ide  fu r the r  suppo r t  f o r  a  n *  e lec t ron i c  g round  s ta te  o fs u l f o n a m i d y l s .  T h e  s o m e w h a t  r e d u c e d  A ,  v a l u e s  ( c a  2  G )  s u g g e s t  s p i n  d e l o c a l i -z a t i o n  o n t o  t h e  a l k o x y  g r o u p .  A g a i n ,  v a r i a t i o n  o f  R ,  e x e r t s  v e r y  l i t t l e  i n f l u -ence  on  the  ESR pa rame te rs :  t he  S0Z  mo ie t y  se rves  as  an  e lec t ron i c  b lock ingg roup .  F rom some p re l im ina ry  quan t i t a t i ve  pho tochemica l  expen imen ts  i t i s  con -1540  r o "  H \,.rr\ rc ---NZ/  \ \ '  r oHt w i s t e d  " n " " ,The  compu ta t i ona l  r esu ls ta tes  o f  ca rboxamidY lso f  su l f onamidY ls  can  befe r  a  ra t i ona le  f o r  t heed  w i th  t hose  o f  su l f onthe odd e lect ron ' in  theas  a  resu l t  o f  a  con t r ic e s s a r i l y  o c c u r  i n  t w i st ions even beYond the Hl i a b l e  d e s c r i P t i o n  o f  tCLwytten 5 deals wisul  fonami dy l  s  3.  The ESsu l  f onami  dy l  s  1 .  Th i  s  csp -hyb r i d i  zed  n i  t r ogenometry around n i t rogenva l  ues  us i  ng  t he  He l  I  e tESR-spectra l  data for  tI n  add i  t i  on  ,  i  n te tf o r  N -b romo-3 '3 -d i -n -P t65b ) .  The  reac t i ons  hav (Chaytten ó containlc a r b a m i d y l s ( 4 , 2 = R 1 (Icluded that  N-alkoxysul fonamidy]s are suf f ic ient ly  ,s tabi . ( izQ-d that  they sur-v i ve  i ong  enough  i n  so lu t i on  t o  f o rm  d imers .  Howeve r ,  t hese  d imers  a re  so  un -s tab le  t ha t  comp l i ca ted  reac t i on  m ix tu res  a re  o f t en  ob ta ined "CLta '1cte,n 4 records the resul  ts  of  the quantum mechani  ca l  ca l  cu l  at i  ons .  Geo-me t r y  op t im iza t i ons  have  p redominan t l y  been  pe r fo rmed  on  d i f f e ren t  s ta tes  (nand  r )  o f  N -me thy l f o rmamidy l  ( 53d )  and  N-me thy lme thanesu l f onamidy l  ( 15d )  rad i -ca l s .  The  fo l l ow ing  op t im ized  s t ruc tu res  have  been  ob ta ined :o .  , 0 .  H  \ - . ,  -  H' . r r \ .  f  ^ , r1. ' " \  "/  l i ; 4 0tw i s ted  "n * " ,  /  CNC =  1200" \ ^ . - ' to - ' ï-* ' í i -  *f  ra3/ t . 7 sH - - - C/ \ _p lanar  n* ,  Á  sNc =  1150The  compu ta t i ona l  r esu l t s  p resen t  ev idence  fo l i n te rac t i on  be tween  the  n  and :s t a t e s  o f  c a r b o x a m i d y l s . 0 n  t h e  o t h e r  h a n d ,  i t  i s  s h o w n  t h a t  t h e  g r o u n d  s t a t eo f  su l f onamidy l s  can  be  desc r i bed  adequa te l y  as  a  ï rN  s ta te .  These  resu l t s  o f -f e r  a  ra t i ona le  f o r  t he  unexpec ted l y  h igh  A*  va lues  o f  ca rboxamidy l s  as  compar -e d  w i t h  t h o s e  o f  s u l f o n a m i d y l s .  A c c o r d i n g l y ,  t h e  m o l e c u l a r  o r b i t a l  c o n t a i n i n gthe  odd  e lec t ron  i n  t he  ca rboxamidy l s  w i l l  have  a  h ighe r  s  cha rac te r ,  ma in l yas  a  resu l t  o f  a  con t r i bu t i on  o f  a  ben t  rN  s ta te .  Such  a  con t r j bu t i on  wou ld  ne -c e s s a n i l y  o c c u l i n  t w i s t e d  c o n f o r m a t i o n s .  I t  i s  a r g u e d  t h a t  f u r t h e r  c a l c u l a -t i ons  even  beyond  the  Har t ree -Fock  l eve l  a re  p robab l y  requ i red  to  ob ta in  a  re -l i ab le  desc r i p t i on  o f  t he  ca rboxamidy l  g round  s ta te .ChctptuL 5 deals wi th an ESR study of  several  four-  and f ive-membered r ingsu l f onamidy l s  3 .  The  ESR pa rame te rs  (Tab1e )  o f  3  a l -mos t  equa l  t hose  o f  acyc l i cs u l f o n a m i d y l s  1 .  T h i s  o b s e r v a t i o n  d e f i n i t e l y  r u l e s  o u t  t h e  p o s s i b i i i t y  o f  a nsp -hyb r i d i zed  n i t r ogen  a tom in  su l f onamidy l s .  Fu r the r  ev idence  fo r  a  p lana r  ge -ome t r y  a round  n i t r ogen  i s  ob ta ined  f rom an  ana l ys i s  o f  t he  expe r imen ta l  AgUv a l u e s  u s i n g  t h e  H e l l e r - M c C o n n e l l  e q u a t i o n .  L a r g e l y  b a s e d  o n  t h e s e  r e s u l t s ,  t h eESR-spec t ra l  da ta  f o r  acyc l i c  and  cyc l i c  ca rboxam ' i dy1s  a re  d i scussed .In  add i t i on ,  i n te res t i ng  Ho fmann-Ló f f l e r  r ea r rangenen ts  have  been  foundfo r  N -b romo-3 ,3 -d i - rT -p ropy l  and  N-b romo-3 ,3 -d i -n -bu ty1  benzy l  su l t ams  (63b  and6 -5b ) .  The  reac t i ons  have  been  pe r fo rmed  unde r  pho to l y t i c  and  the rma l  cond i t i ons .Chay t ten  ó  con ta ins  a  p re l im ina ry  ESR s tudy  o f  u rey l s  (4 ,  Z  =  RTRZN- )  andca rbamidy l s  (4 ,  Z  =  R10 ) .  The  ESR pa rame te rs  (Tab1e )  aga in  sugges t  a  rN  t ype1 5 5ground  s ta te  f o r  t hese  spec ies .  The  sma l l  d i f f e rences  w i th  N -a l ky l ca rboxami -dy l s  can  be  ra t i ona l i zed  i n  t e rms  o f  tw i s t i ng  a round  the  C(0 )N  bond  ra the rt h a n  i n  t e r m s  o f  s p i n  d e l o c a l i z a t i o n .F ina l l y ,  t o  ob ta in  an  unamb iguous  s t ruc tu ra l  ass ignmen t  o f  t he  p roposedsu l f onamidy l s ,  t he  ESR pa rame te rs  o f  seve ra l  co r respond ing  su l f ony l  n i t r ox ideshave  been  de te rm ined .  A t  t he  same t ime ,  su l f ony l  n i t r ox ides  cons t i t u te  an  i n -t e r e s t i n g  c l a s s  o f  f r e e  r a d i c a l s .  T h e i r  E S R  s p e c t r a l  p r o p e r t i e s  a r e  d i s c u s s e d' i  n  Chap te rs  2  and  5 .I n  Append i x  A  the  poss ib le  e lec t ron i c  s ta tes  o f  ca rbox -  and  su l f onamidy lradjcals  are depicted.  Apyte,nd,Lce, t  I  en C deal  wi th the crysta l  s t ructure de-te rm ina t i on  o f  a  f ou r -  and  f i ve -membered  r i ng  su l t am (56a  and  50a ) .i n  d i t  p r o e f s c h r i fs t r u c t u u r  v a n  s u l f o n a m i 'l e n  í R .  C ( 0 ) N R ^ )  .  V o o r  o '' 1 '  a 't r e d e n  a l s  i n t e r m e d i a i rde  g roepen ,  zoa l s  de  sulende  i nv loed  u i t oe feneb e l a n g s t e l  1i n g  h i e r v o o rvergel  i  jkende onderzoekEen  g roo t  aan ta l  ,maakt  en bestudeerd metp i  e .  Deze ami dy1 radj  ca lRISO2  -N  -  R21konden worden gegenereevan  de  ove reenkoms t i geB i  j  deze  be re i  d i  ngsw i  j zgevormde st  i  kstof radi  cai1 ) .  Vanwege  de  ko r te  IE S R - b u i z e n  i d e  t r i I h oIn de Tabel  s taanenke le  1  i t e ra tuu rgegeverad i ca len  z i j n  me t  name156

The electronic structure of sulfonamidyl radicals. An ESR spectroscopic and ab-initio MO study of sulfonamidyl and some carboxamidyl radicals

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The electronic structure of sulfonamidyl radicals. An ESR spectroscopic and ab-initio MO study of sulfonamidyl and some carboxamidyl radicals

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