Halogen-Bonded [N–I–N]− Complexes with Symmetric or Asymmetric Three-Center–Four-Electron Bonds

This is a sel -a chi ed e sion o an o iginal a icle. This e sion may di e om he o iginal in pagina ion and ypog aphic de ails. Au ho (s): Ti le: Yea : Ve sion: Copy igh : Righ s: Righ s u l: Please ci e he o iginal e sion: CC BY 4.0 h ps://c ea i ecommons.o g/licenses/by/4.0/ Halogen-Bonded [N–I–N]− Complexes wi h Symme ic o Asymme ic Th ee- Cen e –Fou -Elec on Bonds © Au ho s, 2023 Published e sion Yu, Shilin; T uong, Khai-Nghi; Siepmann, Ma cel; Sii i, A o; Schumache , Ch is ian; Wa d, Jas S.; Rissanen, Ka i Yu, S., T uong, K.-N., Siepmann, M., Sii i, A., Schumache , C., Wa d, J. S., & Rissanen, K. (2023). Halogen-Bonded [N–I–N]− Complexes wi h Symme ic o Asymme ic Th ee-Cen e –Fou - Elec on Bonds. C ys al G ow h and Design, 23(2), 662-669. h ps://doi.o g/10.1021/acs.cgd.2c01162 2023 Halogen-Bonded [N−I−N]−Complexes wi h Symme ic o Asymme ic Th ee-Cen e −Fou -Elec on Bonds Published as pa o a C ys al G ow h and Design i ual special issue on Nonco alen In e ac ions: Celeb a ing P o . Gu u Row Shilin Yu, ⊥ Khai-Nghi T uong, ⊥ Ma cel Siepmann, A o Sii i, Ch is ian Schumache , Jas S. Wa d, and Ka i Rissanen* Ci e This: h ps://doi.o g/10.1021/acs.cgd.2c01162 Read Online ACCESS Me ics & Mo e A icle Recommenda ions * sı Suppo ing In o ma ion ABSTRACT: A se ies o LH[Z−I−Z] halogen(I) complexes, whe e Z= saccha ina o o ph halimido anions and LH = py idinium, py azinium, e abu yl (TBA)- o e ame hylammo- nium (TMA) ca ions, we e p epa ed, s uc u ally cha ac e ized, and discussed as complexes consis ing o a [N−I−N]−anion wi h a h ee-cen e − ou -elec on (3c-4e) halogen bond, and a hyd ogen- bonding (py idinium o py azinium) o ine (TBA o TMA) ca ion. The symme ic [N−I−N]−anion, eminiscen o he iiodide [I−I−I]−anion, is ound o be s uc u ally equi alen o i s ca ionic analogue [N−I−N]+wi h N−I bond leng hs o 2.26 Å. In con as o he homolep ic [N−I−N]+complexes, asymme y o he N−I bond leng hs (2.21 and 2.28 Å) was obse ed o hose [N−I−N]−complexes which mani es ed a hyd ogen bond o only one saccha ina o moie y, hus being s uc u ally analogous o he asymme ic he e olep ic [N−I−N]+complexes. The esul s show ha he 3c-4e [N−I−N] halogen bond, being ei he posi i ely o nega i ely cha ged, can be asymme ized by an ex e nal hyd ogen bond ([N−I−N]−) o by using wo di e en ligands (he e olep ic [N−I−N]+). O e he las 20 yea s he s udy o he in e ac ions o pola ized halogen a oms wi h nucleophilic coun e pa s, i.e., halogen bonding 1−5 (XB) R−X···Nu (R = any a om, X = halogen, and Nu = a nucleophile), has ma u ed o be an impo an esea ch a ea in he domain o nonco alen in e ac ions and has ecen ly been de ined o occu be ween he elec ophilic egion o a halogen a om and neu al o anionic nucleophiles. 6 The e has been a ecen boom o halogen bonding and o he elec ophile−nucleophile in e - ac ions, such as chalcogen 7 and pnic ogen 8 bonding, as demons a ed by he apid inc ease o publica ions o e he pas decade. 9−11 Halogen bonding has ound u ili y as a nonco alen in e ac ion o cons uc sup amolecula sys ems, and due o he simila i y o he bonding geome ies and di ec ionali y, compa isons wi h hyd ogen bonding can be d awn. Halogen bonding has been success ully applied o con ol he sel - assembly o a mul i ude o hos −gues sys ems (ion-pai ecogni ion, biomolecula /chemical sepa a ions), as well as he syn hesis o ma e ials wi h e sa ile unc ionali ies such as po osi y, magne ism, phospho escence, and liquid c ys allin- i y. 1−5 C ys al enginee ing 1−4,12 has es ablished he di ec ion- ali y and speci ici y o halogen bonding, esul ing in complex s uc u es wi h appealing a chi ec u es, wi h hollow capsula molecula assemblies solely based on classical halogen bonding ha ing been epo ed ecen ly. 13,14 Due o i s elec onic o igin as a σ-hole in e ac ion, halogen bonding is mo e di ec ional han hyd ogen bonding, 15 hough he classical R−X···Nu halogen bonding has been mo e di icul o s udy in solu ion and has he e o e been s udied mos ly in he solid s a e. 16−19 A special niche o halogen-bonding esea ch has eme ged om hose s udies whe e an elec on has been emo ed om he halogen a om, esul ing in a posi i ely cha ged halenium ion, X+(X = I, B , o Cl), ye mo e app op ia ely named as halogen(I) ca ions. Acco ding o he de ini ion o he halogen bond, 6 hese ca ions can be ega ded as e y s ong bis- unc ional XB dono s; howe e , he ee halogen(I) ca ion is highly eac i e and canno be isola ed o used as such. Ne e heless, he halogen(I) ca ions can be s abilized by Recei ed: Oc obe 14, 2022 Re ised: Janua y 19, 2023 Communica ionpubs.acs.o g/c ys al © XXXX The Au ho s. Published by Ame ican Chemical Socie y A h ps://doi.o g/10.1021/acs.cgd.2c01162 C ys . G ow h Des. XXXX, XXX, XXX−XXX Downloaded ia UNIV OF JYVASKYLA on Janua y 30, 2023 a 10:01:35 (UTC). See h ps://pubs.acs.o g/sha ingguidelines o op ions on how o legi ima ely sha e published a icles. complexa ion wi h wo sui able Lewis bases (L), apping hem as a [L−X−L]+complex exhibi ing a h ee-cen e − ou - elec on (3c-4e) bond. Combining an iodine(I) ca ion wi h wo py idine ligands leads o he bis(py idine)iodine(I) ca ion wi h a [N−I−N]+3c-4e bond, epo ed al eady in he 1960s by Hassel e al., 20 C eigh on e al., 21 and Haque e al. 22 Such s abilized halogen(I) complexes ha e a ac ed a lo o a en ion, especially wi hin he halogen bonding communi y, and ha e ecen ly been e iewed. 23,24 The iconic example, bis(py idine)iodine(I) e a luo obo a e (Ba luenga’s e- agen ), 25 is a mild iodina ion eagen and an oxidan . Ba luenga’s eagen is a ela i ely s able whi e solid and is soluble in bo h o ganic and aqueous solu ions, and i s applicabili y in o ganic syn hesis has been widely demon- s a ed. 26 E delyi 27−32 has demons a ed wi h e y p ecise and comp ehensi e s udies in solu ion, supplemen ed wi h compu a ional calcula ions, ha he [N−I−N]+halogen bond has a e y s ong in e ac ion a io RXB < 0.65 (RXB de ined as he sum o he dW adii o he in e ac ing a oms di ided by hei con ac dis ance), as well as being linea and symme ic wi h he iodine a om loca ed in he cen e be ween he N a oms wi h a e y small N−I dis ance a ia ion. O e he las 5 yea s he ield o halogen(I) chemis y has expanded g ea ly, wi h ecen de elopmen s including he i s iodine(I)- based capsules, 33−36 helica es, 37 asymme ic complexes, 38,39 halogen-bonded o ganic amewo ks (XOF), 40 halogen- bonded hie a chical ma e ials, 41 and solid-s a e nucleophilic I+···Ag+in e ac ions. 42−44 In addi ion o he a o emen ioned posi i ely cha ged XB complexes, he almos nea ly as s ong (RXB = 0.65−0.67) bu neu al N−I···N and N−I···O−N XB complexes, which a e easily p epa ed om sui able haloimides and halosul onimides as he XB dono s and py idine de i a i es o py idine N-oxides as he XB accep o s, ha e been ex ensi ely s udied by Fou migue 45,46 and us. 17−19,47,48 Un il e y ecen ly i was belie ed ha o he uncha ged XB complexes canno exhibi halogen bonds (RXB < 0.65) simila ly s ong as hose o a o emen ioned complexes, ye ou ecen wo k on s abilized ca bonyl hypoiodi es 49−51 has shown ha RXB alues below 0.62 a e possible. The composi ionally simila bu nega i ely cha ged [O−I− O] 52,53 o [N−I−N] 54−57 sys ems ha e been much less s udied, and no a all in he con ex o halogen bonding. The ew X- ay s uc u es o he [N−I−N]−sys ems 54−57 as hei e abu ylammonium (TBA) sal s (Figu e 1) mani es s uc u es analogous o hei [N−I−N]+coun e pa s. Co esponding [N−B −N]−X- ay s uc u es ha e been also epo ed ( om ph halimide, CSD codes 58 JUBNEZ, 56 XITPEY, 56 and JEJZED 57 ). Based on he sca ci y o he [N−I−N]−sys ems, we became in e es ed in sys ema ically s udying (Scheme 1) speci ic [N− I−N]−sys ems in he con ex o halogen bonding and compa ing hem o hei ca ionic [N−I−N]+coun e pa s, as well as o he neu al haloimide and hypoiodi e XB sys ems. Inspi ed by he p e ious wo k on halogen-bonded complexes o haloimides and py idine-based ligands, 17−19,45−48 Figu e 1. X- ay s uc u es o [N···I···N]−complexes YUNPUV 54 and DIQWIM. 55 Scheme 1. Lis o Componen s Used in This Wo k: 1 and 4 as he XB Dono s and 3, 6 and L1−L8 as he XB Accep o s Scheme 2. Syn hesis o 1L1 and he Se endipi ous Fo ma ion o L1H[3−I−3] C ys al G ow h & Design pubs.acs.o g/c ys al Communica ion h ps://doi.o g/10.1021/acs.cgd.2c01162 C ys . G ow h Des. XXXX, XXX, XXX−XXX B a cle -con aining dio hosubs i u ed py idine, 2,6-di olyl-4- (dime hylamino)py idine (L1;Scheme 1) was syn hesized h ough a known p ocedu e (see he Suppo ing In o ma ion) o ob ain he expec ed halogen-bonded complex 1L1. The complexa ion o 1(NISac) wi h L1 in CHCl3p oceeded smoo hly, and he 1H NMR spec um (Figu e S3) indica ed he o ma ion o he 1:1 halogen-bonded complex 1L1 (Scheme 2). The e idence ha only he halogen-bonded complex 1L1 o ms in solu ion is clea ly isible in he 1H NMR spec a (Figu e S3), whe e he g adual addi ion o he ligand L1 (Figu e S2) in o he solu ion o N-iodosaccha in (1) sa u a es wi h a 1:1 1:L1 a io, while L1H[3-I-3] would ha e p esen ed i sel wi h a 0.5:1 a io. Howe e , when he eac ion mix u e (1 equi . o L1 wi h a sligh excess o 1) was le o slowly e apo a e, single c ys als o he comple ely unp eceden ed anionic [N−I−N]−complex L1H[3−I−3] we e ob ained (Scheme 2). The composi ion o L1H[3−I−3] consis ed o he p o ona ed L1 ligand (L1H+) and he in si u o med [3−I−3]−complex anion. The s uc u e o he complex anion, which can be ega ded as wo nega i ely cha ged saccha ina o anions and an iodine(I) ca ion o ming a h ee-cen e − ou -elec on (3c-4e) halogen bond be ween he saccha ina o anion ni ogen a oms and he iodine(I) ca ion, was e ealed by SCXRD analysis. We pos ula e ha , upon concen a ion o he eac ion mix u e, he p esence o small amoun s o wa e in he CHCl3sol en likely led o he eac ion whe e 1(N-iodosaccha in), halogen-bonded o he s e ically demanding XB accep o L1, unde wen a e e sible p o ona ion eac ion 59 o a o d 2(saccha in) and HOI (hypoiodous acid), which is e y uns able and apidly Scheme 3. O he Syn he ic Rou es o [N−I−N]−Complexes Table 1. Geome ical Pa ame e s o he [N−I−N]−Complexes complex N−I (Å) I−N (Å) N···N (Å) N−I−N (deg) C−N···N−C (deg) N···O�C (Å) N−H···O�C (deg) L1H[3−I−3] 2.250(4) 2.250(4) 4.479(6) 180 180 2.854(6) a (×2) 141.8 a (×2) 2.239(4) 2.239(4) 4.497(6) 180 180 L1H[3−I−3]H2O 2.265(4) 2.275(4) 4.541(7) 178.8(2) −128.9(2) 2.944(7) a 157.0 a 2.910(7) b 148.1 b L2H[3−I−3] 2.250(5) 2.250(5) 4.500(8) 180 −180 2.708(8) (×2) 146.2 (×2) 2.261(5) 2.261(5) 4.521(8) 180 −180 L3H[3−I−3] c 2.218(4) 2.293(4) 4.512(6) 179.5(2) 174.3(2) 2.733(6) 175.3 L3H[3−I−3] DFT (in DCM) 2.210 2.275 4.484 178.2 165.9 2.746 162.8 L4H[3−I−3] 2.252(8) 2.252(8) 4.502(14) 180 180 2.681(14) (×2) 162.0(×2) 2.262(9) 2.262(9) 4.526(15) 180 180 L5H[3−I−3] c 2.225(5) 2.262(5) 4.487(7) 177.6(2) 31.8(2) 2.821(7) 163.8 L6H[3−I−3] (C-monoclinic) 2.247(5) 2.253(5) 4.499(9) 179.6(2) −176.8(2) L6H[3−I−3] (P-monoclinic) 2.250(5) 2.250(5) 4.499(8) 180 180 2.240(6) 2.240(6) 4.446(8) 180 180 L7H[3−I−3] c 2.217(5) 2.281(5) 4.496(8) 176.3(2) 150.0(2) 2.671(8) 141.8 L8H[3−I−3] d 2.191(7) 2.299(6) 4.486(9) 174.8(2) ±72.2(2) 2.732(9) 178.1 TMA[6−I−6] 2.293(11) 2.293(11) 4.587(14) 180 0.5(4) TMA[6−I−6] DFT (in DCM) 2.235 2.246 4.481 179.2 7.6 a e age (XRD) 2.255(6) 2.258(6) 4.505(9) 179.1(2) a e age c (XRD) (asym) 2.214(5) 2.284(5) 4.495(8) 176.1(2) DIQWIM 54 2.247 2.250 4.495 176.8 36.2 [N−I−N]+(CSD) e 2.260 2.262 4.520 178.5 ca. −140 o +180 ca. 0 ca. +140 o +180 a N−H···O�S. b HO-H···O�C. c Asymme ic [N−I−N], excluded om he a e age N−I calcula ion. d N−H···O hyd ogen bond be ween he mo philinopy idinium moie ies. e The a e age bond geome ies om CSD. Da a analyzed om 58 (97 da a poin s) X- ay s uc u es con aining a [N−I−N]+halogen bond o py idine-based ligands/bases as XB accep o s. The o sion angles o m h ee g oups 1s −140 o −180°, 2nd +140 +180°and he 3 d a ound ze o. The la ge majo i y o he o sion angles a e close o ze o. C ys al G ow h & Design pubs.acs.o g/c ys al Communica ion h ps://doi.o g/10.1021/acs.cgd.2c01162 C ys . G ow h Des. XXXX, XXX, XXX−XXX C unde goes a disp opo iona ion eac ion o o m elemen al iodine. This was also suppo ed by he obse a ion o a deep pinkish colo . Saccha in 2can eac wi h L1, which ac s as a s ong Lewis base, leading o o ma ion o L1H+and he saccha ina o anion 3. The newly o med 3 hen coo dina es wi h 1(N-iodosaccha in), a o ding he anionic [N−I−N]− complex anion [3−I−3]−, which is mo e s able han a mix u e o 1and 3(Scheme 3a). The se endipi ous disco e y o he o ma ion o he L1H[3−I−3] led us o de elop wo di e en syn he ic ou es (Scheme 3) o ob ain simila complexes. The s a ing ma e ials in ou e a) a e solids; hus, o es i mechanochemis y could be used as well, he complex L3H[3−I−3] was p epa ed mechanochemically unde sol en - ee condi ions (see sec ion 2.3 in he Suppo ing In o ma ion). Subsequen c ys alliza ion o he complexes in a sui able sol en (dichlo ome hane, slow e apo a ion, o apo di usion o n-pen ane o e hyl ace a e in o a dichlo ome hane solu ion o he complex) o di ec ly om he eac ion mix u e ( ou e b) led o he o ma ion o he new [N−I−N]−complexes L1H[3−I−3]H2O, L2H[3−I−3], L3H[3−I−3], L4H[3−I−3], L5H[3−I−3], L6H[3−I−3], L7H[3−I−3], and L8H[3−I−3]. Besides he saccha ina o- Figu e 2. X- ay s uc u es o he symme ic [N−I−N]−complexes L1H[3−I−3], L1H[3−I−3]·H2O, L2H[3−I−3], L4H[3−I−3] and L6H[3− I−3] ( he mal displacemen pa ame e s a he 50% p obabili y le el). The as e isk e e s o ca ego y C, om he C-monoclinic polymo ph (Table 1). Figu e 3. X- ay s uc u es o he asymme ic [N−I−N]−complexes L3H[3−I−3], L5H[3−I−3], L7H[3−I−3], and L8H[3−I−3] ( he mal displacemen pa ame e s a he 50% p obabili y le el). C ys al G ow h & Design pubs.acs.o g/c ys al Communica ion h ps://doi.o g/10.1021/acs.cgd.2c01162 C ys . G ow h Des. XXXX, XXX, XXX−XXX D based [3−I−3]−anions, he e ame hylammonium (TMA) sal o he ph halimido-based complex TMA[6−I−6] was also p epa ed using ou e b) (Scheme 3) s a ing om TMA 6 ( e ame hyl ph haloimida o sal ) and 4(N-iodoph halimide). The complex TMA[6−I−6] was p epa ed o compa e he e ec o a ca ion incapable o hyd ogen bonding (TMA) o he hyd ogen-bond dona ing ca ions, L1H+−L8H+. Based on geome ical pa ame e s (Table 1) om he single- c ys al X- ay di ac ion (SCXRD) analysis, he p epa ed [N− I−N]−complexes can be di ided in o h ee ca ego ies: (A) symme ic, HB (L1H[3−I−3], L1H[3−I−3]H2O, L2H[3−I− 3], and L4H[3−I−3]), (B) asymme ic, HB (L3H[3−I−3], L5H[3−I−3], L7H[3−I−3], and L8H[3−I−3]), and (C) symme ic, non-HB (L6H[3−I−3] (C-monoclinic), L6H[3− I−3] (P-monoclinic), and TMA[6−I−6]). As he e is a small a ia ion o he N−I bond dis ances in he known [N−I−N]+ complexes, he de ini ion o asymme y o he [N−I−N]− moie y is based on he s a is ically signi ican de ia ion om he symme ic si ua ion. This has been done by aking in o accoun he es ima ed s anda d de ia ions (esds) o he N−I bond dis ances a he 3σle el. The N−I bond dis ance a e ages (Table 1) in ca ego y A all wi h 99.5% p obabili y be ween 2.237 and 2.273 Å and be ween 2.240 and 2.276 Å and be ween 2.199 and 2.229 Å and be ween 2.267 and 2.299 Å in ca ego y B. The non-HB ca ego y C has only wo examples, wi h he ph halimida o anion [6−I−6]−exhibi ing clea ly longe , symme ic N−I bond dis ances [2.293(11) Å], while bo h polymo phs o L6H[3−I−3] show N−I dis ances analogous o hose o ca ego y A. Simila sys ema ic and s a is ically signi ican di e ences ha e been obse ed only in he he e olep ic [N−I−N]+complexes 60 bu ha e no been obse ed o he homolep ic [N−I−N]+complexes, 23,24,58,59 whe e he a e age N−I bond leng h is 2.26 Å (Table 1). The N−I bond leng hs o all he symme ic species (Figu e 2) a e ema kably wi hin he excep ionally na ow ange o 2.239(4) Å o L1H[3−I−3] and 2.262(9) Å o L4H[3−I−3], which a e all c ys allog aphically indis inguishable om one ano he wi h espec o hei esd alues, wi h he alues hemsel es all lying wi hin he epo ed ange o he analogous [N−I−N]+ complexes. 58,59 The la ges a ia ion was obse ed o he asymme ic (Figu e 3)L8H[3−I−3] wi h N−I bond leng hs o 2.191(7) and 2.299(6) Å, wi h he o me bond leng h being sho e han any epo ed o he analogous [N−I−N]+complexes. The e a e only wo epo ed un es ained asymme ic [N−I− N]+solid-s a e s uc u es, bo h by he au ho s, 38,60 which possess he e olep ic ligands: [I(py idine)(DMAP)]PF6and [I(m z)(DMAP)]PF6(DMAP = 4-dime hylaminopy idine; m z = 1-me hyl-1,2,3- iazole). These complexes exhibi ed N−I bond leng h di e ences o 0.020 and 0.148/0.177 Å (as wo independen molecules we e p esen in he asymme ic uni cell), espec i ely, which makes he N−I bond leng h di e ence induced by hyd ogen bonding in L8H[3−I−3] (0.108 Å) a iable s a egy owa d ins iga ing asymme y in 3c- 4e halogen-bonded complexes (whe he neu al o posi i ely/ nega i ely cha ged), and appa en ly one ha can quan i a i ely i al he me hodology o u ilizing he e olep ic pai s o nucleophiles which su e s om disad an ages like ligand sc ambling. 38,44 The N−I−N angles (Table 1) a e p edominan ly symme y- es ained and he e o e pe ec ly linea (180°), wi h only mino de ia ions om linea i y obse ed o he asymme ic complexes (maximum o 174.8(2)° o L8H[3−I−3]). As no ed p e iously o [N−I−N]+and neu al O−I−N complexes, 23,24,27−32,49−51 he N···N in amolecula dis ances wi hin he complexes a e dic a ed by he elec onic conside a ions o he iodine(I) ca ions which igh ly es ic s his dis ance as i sa is ies i s own elec onic needs. This is e lec ed in he negligible de ia ion om he a e age alues o 4.505(9) Å (symme ic) and 4.495(8) Å (asymme ic) o all complexes (Table 1), which is a mos 0.049 Å o he asymme ic complex L6H[3−I−3]. Howe e , his is no including TMA[6−I−6] (Figu e 4) ha exhibi s a sligh ly la ge de ia ion o 0.082 Å, which con ains a much mo e s e ically bulky ca ion ha canno be di ec ly compa ed o he o he examples. Due o he known inaccu acy o he hyd ogen a om posi ions (calcula ed o hei idealized posi ions and e ined as iding a oms), he hea ie elemen (N and O) dis ances a e ins ead gi en o he NH hyd ogen-bond dono s o he (C�) O hyd ogen-bond accep o g oups. These in e molecula dis ances ange om 2.67(1) o 2.94(1) Å (Table 1) and can all be conside ed hyd ogen bond con ac s o easonable s eng h. To p o ide insigh in o whe he he packing in e ac ions in he asymme ic complexes (ca ego y B) play a la ge ole han he hyd ogen bonding, a DFT calcula ion in solu ion was pe o med (SPARTAN20, 61 M06-2X/de 2-TZVP wi h C- PCM DCM sol en model; see he Suppo ing In o ma ion o de ails) o L3H[3−I−3]. The compu a ionally ob ained geome y (Table 1 and Figu e 3) o L3H[3−I−3] ag ees su p isingly well wi h he c ys allog aphically de e mined s uc u e, wi h a de ia ions o only +0.008 and −0.018 Å o he N−I bond dis ances, −0.028 Å o he N···N dis ances, and −1.3° o he N−I−N angle. This clea ly indica es ha he packing o ces in ca ego y B a e no he cause o he asymme ic [N−I−N]−moie y bu ha i is caused by he hyd ogen bonding om he HB-dono ca ion o only one o he saccha ina o ligands (Figu e 3). In he DFT-calcula ed Figu e 4. X- ay s uc u e o TMA[6−I−6] ( he mal displacemen pa ame e s a he 50% p obabili y le el; le ) and he DFT s uc u e (M06-2X/ de 2-TZVP wi h C-PCM DCM sol en model; igh ). C ys al G ow h & Design pubs.acs.o g/c ys al Communica ion h ps://doi.o g/10.1021/acs.cgd.2c01162 C ys . G ow h Des. XXXX, XXX, XXX−XXX E model o L3H[3−I−3] S�O···cen oid(py) is 2.969 Å wi h an o hogonal o ien a ion ( o sion S−O−N−C = 89.4°,Figu e 3) owa d he S�O bond, indica ing a O···πin e ac ion. In he X- ay s uc u e o L3H[3−I−3] he same o sion angle is −8.6°(Figu e 3), no mani es ing he same py idinium ca ion O···πin e ac ion due o he weak H-bonds o he S�O g oups o he adjacen [3−I−3]−anions. As he ph halimida o-based complex TMA[6−I−6] (Figu e 4) shows symme ic bu longe N−I bond dis ances (Table 1), i s s uc u e was also compu a ionally s udied as wi h L3H[3−I−3] (Figu e 4). The compu ed geome y di e s in all geome ical pa ame e s om he SCXRD-ob ained s uc u e, excep o he N−I−N angle (Table 1). The DFT-ob ained N−I bond dis ances a e no symme ical (2.235 s 2.246 Å) and de ia e −0.058 and −0.047 Å om he SCXRD alues. The N···N leng h also de ia es −0.106 Å om he SCXRD alue (Table 1). This small, bu ma ked, de ia ion be ween he DFT and SCXRD alues esul s om he packing in e ac ions be ween he TMA ca ion and he [6−I−6]−anion, as hey o m a 1-D polyme , [···TMA+···[6−I−6]−···TMA+···[6−I−6]−···TMA+···[6−I− 6]−···]n, in he solid s a e (Figu e S6 in he Suppo ing In o ma ion). In conclusion, a se ies o anionic [N−I−N]−complexes con aining hyd ogen-bond accep o s on he N-based ligands we e syn hesized and cha ge-balanced wi h a a ie y o di e en hyd ogen-bond dono s. The esul ing complexes could be so ed in o h ee g oups based on SCXRD s udies: symme ic HB (hyd ogen-bonded), asymme ic HB, and asymme ic non-HB. The X- ay s udies e ealed wo impo an ou comes; he anionic halogen-bonded [N−I−N]−complexes we e s uc u ally simila o hei ca ionic [N−I−N]+analogues, wi h a nea -iden ical ange o N−I bond leng hs being obse ed, and asymme y in he N−I bond leng hs o he [N−I−N]−complexes could be in oduced ia hyd ogen bonding o one o hei ni ogen-based ligands, wi h me ics compa able o o su passing hose o he asymme y esul ing om he s a egy o c ea ing he e olep ic [N1−I−N2]+ sys ems, which su e om he disad an age o ligand sc ambling, and which is no an issue o he homolep ic complexes epo ed he ein. ■ASSOCIATED CONTENT * sı Suppo 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.cgd.2c01162. Expe imen al de ails, syn hesis and single c ys al p epa a ion, and single-c ys al di ac ion da a (PDF) Accession Codes CCDC 2212725−2212735 con ain he supplemen a y c ys- allog aphic da a o his pape . These da a can be ob ained ee o cha ge ia www.ccdc.cam.ac.uk/da a_ eques /ci , o by emailing [email p o ec ed], o by con ac ing The Camb idge C ys allog aphic Da a Cen e, 12 Union Road, Camb idge CB2 1EZ, UK; ax: +44 1223 336033. ■AUTHOR INFORMATION Co esponding Au ho Ka i Rissanen −Uni e si y o Jy askyla, Depa men o Chemis y, 40014 Jy äskylä, Finland; o cid.o g/0000- 0002-7282-8419; Email: [email p o ec ed] Au ho s Shilin Yu −Uni e si y o Jy askyla, Depa men o Chemis y, 40014 Jy äskylä, Finland Khai-Nghi T uong −Uni e si y o Jy askyla, Depa men o Chemis y, 40014 Jy äskylä, Finland Ma cel Siepmann −Uni e si y o Jy askyla, Depa men o Chemis y, 40014 Jy äskylä, Finland A o Sii i −Uni e si y o Jy askyla, Depa men o Chemis y, 40014 Jy äskylä, Finland Ch is ian Schumache −RWTH Aachen Uni e si y, Ins i u e o O ganic Chemis y, 52074 Aachen, Ge many; o cid.o g/0000-0003-3056-554X Jas S. Wa d −Uni e si y o Jy askyla, Depa men o Chemis y, 40014 Jy äskylä, Finland; o cid.o g/0000- 0001-9089-9643 Comple e con ac in o ma ion is a ailable a : h ps://pubs.acs.o g/10.1021/acs.cgd.2c01162 Au ho Con ibu ions ⊥ S.Y. and K.-N.T. con ibu ed equally o he expe imen al wo k. The manusc ip was w i en h ough con ibu ions o all au ho s. All au ho s ha e gi en app o al o he inal e sion o he manusc ip . Funding The Academy o Finland (K.R., g an no. 351121), he Magnus Eh n oo h Founda ion (J.S.W.), and he Uni e si y o Jy askyla. C.S. is g a e ul o a DAAD sho - e m g an o doc o al s uden s and a Kekuleschola ship p o ided by he Ve band de Chemischen Indus ie e.V. No es The au ho s decla e no compe ing inancial in e es . ■ACKNOWLEDGMENTS We kindly acknowledge he inancial suppo om he a o emen ioned unding sou ces. ■REFERENCES (1) Ca allo, G.; Me angolo, P.; Milani, R.; Pila i, T.; P iimagi, A.; Resna i, G.; Te aneo, G. The Halogen Bond. Chem. Re . 2016,116 (4), 2478−2601. (2) Gilday, L. C.; Robinson, S. W.; Ba end , T. A.; Lang on, M. J.; Mullaney, B. R.; Bee , P. D. Halogen Bonding in Sup amolecula Chemis y. Chem. Re . 2015,115 (15), 7118−7195. (3) Kolá , M. H.; Hobza, P. Compu e Modeling o Halogen Bonds and O he σ-Hole In e ac ions. Chem. Re . 2016,116 (9), 5155− 5187. (4) Wang, H.; Wang, W.; Jin, W. J. σ-Hole Bond s π-Hole Bond: A Compa ison Based on Halogen Bond. Chem. Re . 2016,116 (9), 5072−5104. (5) Pancholi, J.; Bee , P. D. Halogen Bonding Mo i s o Anion Recogni ion. Coo d. Chem. Re . 2020,416, 213281. (6) Desi aju, G. R.; Ho, P. S.; Kloo, L.; Legon, A. C.; Ma qua d , R.; Me angolo, P.; Poli ze , P.; Resna i, G.; Rissanen, K. De ini ion o he Halogen Bond (IUPAC Recommenda ions 2013). Pu e Appl. Chem. 2013,85 (8), 1711−1713. (7) Aake oy, C. B.; B yce, D. L.; Desi aju, G. R.; F on e a, A.; Legon, A. C.; Nico a, F.; Rissanen, K.; Scheine , S.; Te aneo, G.; Me angolo, P.; Resna i, G. De ini ion o he Chalcogen Bond (IUPAC Recommenda ions 2019). Pu e Appl. Chem. 2019,91, 1889− 1892. (8) Va adwaj, A.; Va adwaj, P. R.; Ma ques, H. M.; Yamashi a, K. De ini ion o he Pnic ogen Bond: A Pe spec i e. Ino ganics. 2022,10, 149. C ys al G ow h & Design pubs.acs.o g/c ys al Communica ion h ps://doi.o g/10.1021/acs.cgd.2c01162 C ys . G ow h Des. XXXX, XXX, XXX−XXX F (9) Robidas, R.; Reinha d, D. L.; Legaul , C. Y.; Hube , S. M. Iodine(III)-Based Halogen Bond Dono s: P ope ies and Applica- ions. Chem. Rec. 2021,21, 1912−1927. (10) Szell, P. M. J.; Zablo ny, S.; B yce, D. L. Halogen Bonding as a Sup amolecula Dynamics Ca alys . Na . Commun. 2019,10 (1), 916. (11) Saccone, M.; Ca alano, L. Halogen Bonding beyond C ys als in Ma e ials Science. J. Phys. Chem. B 2019,123 (44), 9281−9290. (12) Rissanen, K. Halogen Bonded Sup amolecula Complexes and Ne wo ks. C ys EngComm 2008,10 (9), 1107−1113. (13) Dumele, O.; T app, N.; Diede ich, F. Halogen Bonding Molecula Capsules. Angew. Chem., In . Ed. 2015,54 (42), 12339− 12344. (14) Beyeh, N. K.; Pan, F.; Rissanen, K. A Halogen-Bonded Dime ic Reso cina ene Capsule. Angew. Chem., In . Ed. 2015,54 (25), 7303− 7307. (15) A unan, E.; Desi aju, G. R.; Klein, R. A.; Sadlej, J.; Scheine , S.; Alko a, I.; Cla y, D. C.; C ab ee, R. H.; Dannenbe g, J. J.; Hobza, P.; Kjae gaa d, H. G.; Legon, A. C.; Mennucci, B.; Nesbi , D. J. De ining he Hyd ogen Bond: An Accoun (IUPAC Technical Repo ). Pu e Appl. Chem. 2011,83 (8), 1619−1636. (16) T o , R. W.; Mäkelä, T.; Topic, F.; Valkonen, A.; Raa ikainen, K.; Rissanen, K. Al e na i e Mo i s o Halogen Bonding. Eu . J. O g. Chem. 2013,2013, 1617−1637. (17) Raa ikainen, K.; Rissanen, K. In e ac ion be ween Amines and N-Haloimides: A New Mo i o Unp eceden edly Sho B ···N and I···N Halogen Bonds. C ys EngComm 2011,13 (23), 6972−6977. (18) Raa ikainen, K.; Rissanen, K. B ea hing Molecula C ys als: Halogen- and Hyd ogen-Bonded Po ous Molecula C ys als wi h Sol en Induced Adap a ion o he Nanosized Channels. Chem. Sci. 2012,3(4), 1235−1239. (19) Pu eddy, R.; Ju cek, O.; Bhowmik, S.; Mäkelä, T.; Rissanen, K. Ve y S ong −N−X+···−O−N+ Halogen Bonds. Chem. Commun. 2016,52 (11), 2338−2341. (20) Hassel, O.; Hope, H.; Sö ensen, N. A.; Dam, H.; Sjöbe g, B.; To , J. S uc u e o he Solid Compound Fo med by Addi ion o Two Molecules o Iodine o One Molecule o Py idine. Ac a Chem. Scand. 1961,15, 407−416. (21) C eigh on, J. A.; Haque, I.; Wood, J. L. The Iododipy idinium Ion. Chem. Commun. 1966, No. 8, 229. (22) Haque, I.; Wood, J. L. The Vib a ional Spec a and S uc u e o he Bis(Py idine)Iodine(I), Bis(Py idine)B omine(I), Bis(γ- Picoline)Iodine-(I) and Bis(γ-Picollne)B omine(I) Ca ions. J. Mol. S uc . 1968,2(3), 217−238. (23) Tu unen, L.; E délyi, M. Halogen Bonds o Halonium Ions. Chem. Soc. Re . 2020,49 (9), 2688−2700. (24) Hakke , S. B.; E délyi, M. Halogen Bond Symme y: The N− X−N Bond. J. Phys. O g. Chem. 2015,28 (3), 226−233. (25) Ba luenga, J.; T incado, M.; Rubio, E.; González, J. M. IPy2BF4-P omo ed In amolecula Addi ion o Masked and Un- masked Anilines o Alkynes: Di ec Assembly o 3-Iodoindole Co es. Angew. Chem., In . Ed. 2003,42 (21), 2406−2409. (26) Chalke , J. M.; Thompson, A. L.; Da is, B. G. Sa e and Scalable P epa a ion o Ba luenga’s Reagen . O ganic Syn heses. 2011, No. 87, 288−298. (27) on de Heiden, D.; Vande kooy, A.; E délyi, M. Halogen Bonding in Solu ion: NMR Spec oscopic App oaches. Coo d. Chem. Re . 2020,407, 213147. (28) Lindblad, S.; Mehme i, K.; Veiga, A. X.; Nekoueishah aki, B.; G ä ens ein, J.; E délyi, M. Halogen Bond Asymme y in Solu ion. J. Am. Chem. Soc. 2018,140 (41), 13503−13513. (29) Ka im, A.; Rei i, M.; Ca lsson, A.-C. C.; G ä ens ein, J.; E délyi, M. The Na u e o [N−Cl−N]+ and [N−F−N]+ Halogen Bonds in Solu ion. Chem. Sci. 2014,5(8), 3226−3233. (30) Ca lsson, A.-C. C.; Uh bom, M.; Ka im, A.; B a h, U.; G ä ens ein, J.; E délyi, M. Sol en E ec s on Halogen Bond Symme y. C ys EngComm 2013,15 (16), 3087−3092. (31) Ca lsson, A.-C. C.; G ä ens ein, J.; Budnjo, A.; Lau ila, J. L.; Be gquis , J.; Ka im, A.; Kleinmaie , R.; B a h, U.; E délyi, M. Symme ic Halogen Bonding Is P e e ed in Solu ion. J. Am. Chem. Soc. 2012,134 (12), 5706−5715. (32) Ca lsson, A.-C. C.; G ä ens ein, J.; Lau ila, J. L.; Be gquis , J.; E délyi, M. Symme y o [N−X−N]+halogen Bonds in Solu ion. Chem. Commun. 2012,48 (10), 1458−1460. (33) Tu unen, L.; Wa zok, U.; Pu eddy, R.; Beyeh, N. K.; Schalley, C. A.; Rissanen, K. [N···I+···N] Halogen-Bonded Dime ic Capsules om Te akis(3-Py idyl)E hylene Ca i ands. Angew. Chem., In . Ed. 2016,55 (45), 14033−14036. (34) Tu unen, L.; Peu onen, A.; Fo sblom, S.; Kalenius, E.; Lah inen, M.; Rissanen, K. Te ame ic and Dime ic [N···I+···N] Halogen-Bonded Sup amolecula Cages. Chem. - Eu . J. 2017,23 (48), 11714−11718. (35) Tu unen, L.; Wa zok, U.; Schalley, C. A.; Rissanen, K. Nano- Sized I12L6Molecula Capsules Based on he [N···I+···N] Halogen Bond. Chem. 2017,3(5), 861−869. (36) Taipale, E.; Wa d, J. S.; Fio ini, G.; S a es, D. L.; Schalley, C. A.; Rissanen, K. Dime ic Iodine(i) and Sil e (i) Cages om T ipodal N-Dono Ligands ia he [N−Ag−N]+ o [N−I−N]+ Ca ion Exchange Reac ion. Ino g. Chem. F on . 2022,9(10), 2231−2239. (37) Vande kooy, A.; Gup a, A. K.; Földes, T.; Lindblad, S.; O habe , A.; Pápai, I.; E délyi, M. Halogen Bonding Helica es Encompassing Iodonium Ca ions. Angew. Chem., In . Ed. 2019,58 (27), 9012−9016. (38) Wa d, J. S.; Fio ini, G.; F on e a, A.; Rissanen, K. Asymme ic [N−I−N]+ Halonium Complexes. Chem. Commun. 2020,56 (60), 8428−8431. (39) Taipale, E.; Siepmann, M.; T uong, K.-N.; Rissanen, K. Iodine(I) and Sil e (I) Complexes o Benzoimidazole and Py - idylca bazole De i a i es. Chem. - Eu . J. 2021,27, 17412−17419. (40) Gong, G.; L , S.; Han, J.; Xie, F.; Li, Q.; Xia, N.; Zeng, W.; Chen, Y.; Wang, L.; Wang, J.; Chen, S. Halogen-Bonded O ganic F amewo k (XOF) Based on Iodonium-B idged N···I+···N In e - ac ions: A Type o Diphase Pe iodic O ganic Ne wo k. Angew. Chem., In . Ed. 2021,60 (27), 14831−14835. (41) Wa d, J. S. The solid-s a e hie a chy and iodina ion po en ial o [bis(3-ace aminopy idine)iodine(I)]PF6.C ys EngComm. 2022,24, 7029. (42) Yu, S.; Kuma , P.; Wa d, J. S.; F on e a, A.; Rissanen, K. A “Nucleophilic” Iodine in a Halogen-Bonded Iodonium Complex Mani es s an Unp eceden ed I+···Ag+ In e ac ion. Chem. 2021,7(4), 948−958. (43) Wa d, J. S.; F on e a, A.; Rissanen, K. U ili y o Th ee- Coo dina e Sil e Complexes Towa d he Fo ma ion o Iodonium Ions. Ino g. Chem. 2021,60 (7), 5383−5390. (44) Wilcox, S.; Se hio, D.; Wa d, J. S.; F on e a, A.; Lindh, R.; Rissanen, K.; E délyi, M. Do 2-Coo dina e Iodine(i) and Sil e (i) Complexes Fo m Nucleophilic Iodonium In e ac ions (NIIs) in Solu ion? Chem. Commun. 2022,58 (32), 4977−4980. (45) Makho kina, O.; Lie ig, J.; Jeannin, O.; Fou migué, M.; Aube , E.; Espinosa, E. Coc ys al o Sal : Solid S a e-Con olled Iodine Shi in C ys alline Halogen-Bonded Sys ems. C ys . G ow h Des. 2015,15 (7), 3464−3473. (46) Aube , E.; Espinosa, E.; Nicolas, I.; Jeannin, O.; Fou migué, M. Towa d a Re e se Hie a chy o Halogen Bonding be ween B omine and Iodine. Fa aday Discuss. 2017,203, 389−406. (47) Pu eddy, R.; Rau iainen, J. M.; Mäkelä, T.; Rissanen, K. S ong N−X···O−N Halogen Bonds: A Comp ehensi e S udy on N- Halosaccha in Py idine N-Oxide Complexes. Angew. Chem., In . Ed. 2019,58 (51), 18610−18618. (48) Any an i, G.; Bauzá, A.; Gen iluomo, L.; Rod igues, J.; Po alone, G.; F on e a, A.; Rissanen, K.; Pu eddy, R. Sho X···N Halogen Bonds Wi h Hexame hylene e aamine as he Accep o . F on . Chem. 2021,9, 623595. (49) Yu, S.; Wa d, J. S.; T uong, K.-N.; Rissanen, K. Ca bonyl Hypoiodi es as Ex emely S ong Halogen Bond Dono s. Angew. Chem., In . Ed. 2021,60 (38), 20739−20743. C ys al G ow h & Design pubs.acs.o g/c ys al Communica ion h ps://doi.o g/10.1021/acs.cgd.2c01162 C ys . G ow h Des. XXXX, XXX, XXX−XXX G (50) K ame , E.; Yu, S.; Wa d, J. S.; Rissanen, K. Dihypoiodi es S abilised by 4-E hylpy idine h ough O−I−N Halogen Bonds. Dal . T ans. 2021,50 (42), 14990−14993. (51) Wa d, J. S.; Ma ono a, J.; Wilson, L. M. E.; K ame , E.; Aa , R.; Rissanen, K. Ca bonyl Hypoiodi es om Pi alic and T imesic Acid and Thei Sil e (i) In e media es. Dal . T ans. 2022,51 (38), 14646−14653. (52) Muniz, K.; Ga cía, B.; Ma ínez, C.; Piccinelli, A. Dioxoiodane Compounds as Ve sa ile Sou ces o Iodine(I) Chemis y. Chem. - Eu . J. 2017,23 (7), 1539−1545. (53) Kand nálo á, M.; Kokan, Z.; Ha el, V.; Necas, M.; Sindelá , V. Hype alen Iodine Based Re e sible Co alen Bond in Ro axane Syn hesis. Angew. Chem., In . Ed. 2019,58 (50), 18182−18185. (54) Guzmán San iago, A. J.; B own, C. A.; Somme , R. D.; Ison, E. A. Iden i ica ion o Key Func ionaliza ion Species in he Cp*I (Iii)- Ca alyzed-O ho Halogena ion o Benzamides. Dal . T ans. 2020,49 (45), 16166−16174. (55) Lucche i, N.; Tkache a, A.; Fan asia, S.; Muniz, K. Radical C− H-Amina ion o He e oa enes Using Dual Ini ia ion by Visible Ligh and Iodine. Ad . Syn h. Ca al. 2018,360 (20), 3889−3893. (56) Be ges, J.; Ga cía, B.; Muniz, K. An Elec ophilic B omine Redox Ca alysis o he Syn hesis o Indole Alkaloid Building Blocks by Selec i e Alipha ic C−H Amina ion. Angew. Chem., In . Ed. 2018, 57 (48), 15891−15895. (57) Elding, M.; La sson, A. K.; S ensson, G.; Albe sson, J.; Ebe son, L. S uc u e o a ′hype alen ’ Linea Bis(Ph halimida o)- B oma e(I) Complex. Ac a C ys allog . Sec . C C ys . S uc . Commun. 1992,48 (11), 2078−2080. (58) G oom, C. R.; B uno, I. J.; Ligh oo , M. P.; Wa d, S. C. CSD2022.2, The Camb idge S uc u al Da abase. Ac a C ys allog . 2016,B72, 171−179. (59) Wa d, J. S.; T uong, K.-N.; E délyi, M.; Rissanen, Halogen- Bonded Halogen(I) Ion Complexes, Comp ehensi e Ino ganic Chemis y III; Else ie : 2023. DOI: 10.1016/B978-0-12-823144- 9.00043-1. (60) Yu, S.; Wa d, J. S. Ligand Exchange among Iodine(i) Complexes. 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