Dibenzo (f,o)-2,3-bis(hidroksilmino)-1,4-diaza-8,11,14-trioksa-2,3,9,10,12,13- heksahidrosikloheptadesin`in sentezi ve komplekslerinin incelenmesi

Abstract

II II. ÖZET Farklı koordinasyon bileşikleri oluşturan' makrosiklik bileşikler ve vic-dioksimler üzerinde ayrı ayrı birçok çalışma yapılmış olmasına karşılık, bu iki donör özelliği birarada içeren bileşiklerle ilgili çalışmalar çok az sayıdadır. Poliheteroatom olarak oksijen ihtiva eden taç eterler alkali metalleri ile kararlı kompleksler oluşturur; Poliaza-makrosiklik ligandların geçiş metal leri ile kompleks oluşturma eğilimi de- bilinmektedir. Hem okso- hem de ozo- gurupları taşıyan makrosiklik bileşikler ise, her iki gurup metal iyonu ile bazan kompleks oluşturmakta, bazan da kompleksleri izole etmek mümkün olamamaktadır. Burada molekülün sterik yapısı önemli rol oynar. Bu çalışmada önce dietilenglikol ve salisiladdehitten başlıyarak, çok kademeli reaksiyonlar sonucunda yeni bir diamin bileşiği olan dietiienglikol-0,01 -bis(2~benzilamin) dihidroklorür elde edilmiştir, Bu diamin'in aşırı NaHC03 yanında anti-diklorogliok- sim ile reaksiyona sokulmasından 17-üyeli halka yapısın daki dibenzoLf, o]-2, 3-bis(hidroksiimino)-l,4-diaza-8, 11, 14- trioksa-2, 3, 9, 10, 12, 13-heksahidrosikloheptadesin (LH^ ) sentezi başarılmıştır. Herhangi bir template (yönlendirme) etkinin söz konusju olmadığı bu reaksiyonda şartların uy gun şekilde.' ayarlanmasıyla verim % 46,5'e kadar yükseltilebilmiştir. Elde edilen/yeni ligandın yapısı elementel analiz, kütle, H-n.m.r., i.r, ve u.v.-görünür bölge spektral verilerine göre belirlenmiştir, yic-Dioksim guruplarının ant i- formunda ? /olduğu i.r. de 3220 cm` de çıkan v(O-H)Ill bandı ve H-n.m.r. spektrymunda 10.3 ppm de görülen tek bir geniş singlet vasıtasıyla doğrulanmıştır.. Daha önce sentezi gerçekleştirilen 15-Uyeli benzer bir makrosiklik vic-dioksim olan dibenzo[e,,m]-2, 3-bis (hidroksiimino)-!, ^--diaza-Z/lO, 13-trioksapentadesin ' in yalnız yic-dloksİBir'guruplorı üzerinden koordinasyona girmesine karşılık/ İ-H, hem makrosiklik halkadaki hete- roatomlar hem de yic-dioksimlerden koordinasyon yapabil mektedir. LH4/ iyon yarıçapları 0.7 A° civarında olan Cu(II)/r Ni(ll) ve Go(II) ile metal-ligand oranı 1:2 olan kompleksler' vermiş, iyon yarıçapları 0.8 A olan Pd(II) ve UOjtVI) İle ise trinükleer kompleksleri izole edilmiştir. Bu durumda aromatik halkaya komşu metilen guruplarının oyuk çapını ve molekülün sterik yapısını etkilemesi sonucunda, uygun büyüklükte olan iyonlarla makrosiklik yapının kompleks oluşturmasını mümkün kıldığı söylenebilir. izole edilen mono-nUkleer Cu(II), Ni(II), Co(II) ve trinükleer Pd( I I ) # UO«(VI) komplekslerinin yapısı elemen iz' ?.-.*.' tel analiz, H-n.m.r.,, i. r,, u.v. -görünür bölge spektrumları ve magnetik ölçümler yoluyla aydınlatılmaya çalışılmıştır.

IV III. SUMMARY I' The interesting unusual ion-binding properties of macrocyclic polyethers, polyamines, polythioethers, and other related molecules have received considerable attention and many reviews have appeared about their syntheses and properties* While macrocyclic polyether compounds «on form complexes with only alkali metal ions, macr(ocycles with N and S donor sites are also capable of forming transition-metal complexes. ^ In the previous papers of our group, the structures of various transition metal complexes of diaminoglyoxime and its N,N' -disubstituted derivatives were studied. In the synthesis of most of these new liggnds, anti-dichloro- glyoxime was used as potential vic-dioxime source. The last three papers reported the synthesis of macrocyclic ligands with additional vic-dioxime donor groups. N,N'- bis(4' -benzo[15-crown-5 ]) diaminoglyoxime farmed transition- metal ion complexes through vic-dioxime group;and Na complexes with the crown ether moieties. Diberizo[e, k]-2, 3- bis(hydroxyimino)-l,4, 7, 10-tetraaza-2, 3, 8, y-tetrahydro- cyclododecine gave tri-nucieqr complexes by coordinating.?. through both aza-groups in the heterocycle. and vic-dioxime groups. Dibenzo[e, k]-2, 3~bis(hydroxyimino)-l,4-diaza-7, 10- dioxa-2, 3, 8, 9-tetrahydrocyclododecine and its 15,18 and 21-membered' analogs Containing 3,4 and 5-oxa groups, in contrast to the above ligand, gave only mono-nuclear comp lexes with various transition metal ions. In the present work, we describe the synthesis of a similar 17-membered macrocyclic vic-dioxime and its complexation with Ou( II), Ni(II), Co(II), Pd(II) and U02(VI).Starting with saliçyl aldehyde and diethylene glycoldi- tosylate, ethylene glycol-0,0' -bis(2-benzaldehyde) was obtained and it was converted to oxime by heating with hydroxylamine in ethanol. In order to reach the benzyl- amine step, the oxime was reduced with Na-amqigam as in the case of p-hydroxybenzylqmine. In the synthesis of dibenzo Cf,o]-2,3-bis(hydroxyimino)- 1, 4-diaza-S, 11, 14-triqxa-2, 3', ?, 10, 12, 13-hexqhydrocyclp- heptadecine (LH,), the cyclization reaction was accomp lished without any template effect by the reaction of. :> diethyleneglycol-0,01 -bis(2-benzylamine) with cnti-dichloro- glyoXime. NaHCO» was used to neutralize HC1 formed during the reaction. The low tendency of alkali «> metal ions to make complexes with N-containing ligands prohibits the template effect of alkali-metal ions. The synthesis of similar macrocyclic multidentate compounds with 2-aza-and 2/3, or 4 oxa^groups were reported by treating ethylene-» diamine with diacid chlorides prepared from the appropriate dioxodioic acids. The yields of these macrocodes were reported to be between 8.0-46.0 % and the reactions were untemplated. Consequently, the cyclizdtion reaction in LH^ can be considered untemplated. Elemental analytical results are in accordance with ^20^24^4^5' *n *ne mass spectrum of LH^, a peak corresponding ? to M-58 is, observed instead of molecular ion. This fragments- l tion is expected for macrocyclic compounds. The high resolution mass spectrum enables us to determine the elemental composition of the fragment (342.158046) to be C19H22^2°4 whicn can De obtained by elimination of (HN=C=N-0H)from, the molecular ion. In the i.r. spectrum of LH4, (N-H), (OH), (ON'), and j-VI (N-Q) stretching frequencies were observed at 3400, 3220, 1625, and 940 cm respectively. Bands due to.(Ax-O-C) and (C-O-C). stretches are at 1245 and 1120 cm.. All these absorptions are in agreement with those previously reported `.'? 1 ? for diaminoglyoxime derivatives. In the H-n.m.r. spectrum of LH,', the D~0 exchangeable protons of (OH) and (NH) groups show chemical shifts of 10. 3 and 7. 9 ppm. The multiplets for aromatic (7.4-7. 0;ppm). and etheral (CH?- CH2-0) (3. 6-3, 3. ppm), protons have appeared in their usual values. A single chemical shift for (OH) protons indicates* that the oxime groups are in antl^form, Dibenzo [f, g ]-2, 3-bis(hydroxyimino)-l,4-dia2a-8, 11, 14-trioxa- 2, 3, 9, 10, 12, 13-hexahydrocycloheptadecine (LH*).i ' VII ! / In LH,, the 17-membered macrocycle contains 3-oxa and : 2-aza groups. Consequently, the geometry of the cavity and I the nature of the donor sites will play important role in ! complexation selectivity. Nitrogen as a donor site plays Ithe role of a mediator by promoting the complexation of J transition metal ions without drastically-diminishing that of alkali metals as well. In our previous work, alkali or transition metal complexes of the 15-membered macrocycle with the same donor sites, namely dibenzo[e, m ]-2,3-bis (hydrQxyimino)-l,4-diazq-7, 10, 13-trioxa-pentadecine, could % J not be isolated. Though the presence of two methylene groups enlarges the macrocyle, it also changes the stereo chemistry of the ligandjf as it can be seen on models, only four of the donor sites (2N and 20) can be directed to the metal ion. ' ' While all five transition metal ions, Cu(II), Ni(II),.Co(II), PdClI),, and U02(VI) formed NN-chelates through two vic-dioxime groups, only Pd(II) and U02(VI) were capable of forming complexes with the macrocyclic ring, so only :'. these two metal ions gave tri-nuclear complexes as dibenzo [e,k3-2,3-bis(hydroxyimino)-l,4,7,10-tetraaza-2, 3, 8,?? ' tetrahydrocyclododecine. The reason for selectivity is iprobably due to the cavity diameter and the ionic radius, I since atomic radii of Pd and U is about 0.80 A and 1 2+ 2+ 2+ o those of Cu, Ni, Co are about 0.70. iA^. Armstrong et jal has shown that an increase in macrocycle ring size causes rto decrease the ligand field strength. (LH3)2M complexes where M=Cu(n), Ni(II), andCo(II), show the characteristic features of- vic-dioxime complexes. jThe disdppearence of the (OH), stretching band and the shift of the (C=N) band to lower frequency in i.r. spectra of I L. İVIII (LH,) `2 M complexes can be attributed to NN-çhelati.on^ The Bending vibrations of (O^H...0) bridges appear at 1710 an / -1 Q- H-- 0 Q- -H-.0 The magnetic susceptibility measurements of (LH-KM indicate that Ni(II) complex is diqmqgnetic and the magnetic moments of ?Cu('I.I) and Co(II) complexes are 1.69 and 2.11 BM respectively* The^se results are in agrement with the square-planar structures of the complexes. In'the tri~nuclear Pd(II) and -UQjfVI) complexes of LH^/ one metal ion is coordinated to 2 aza- and 2 oxa- groups İn each macrocycle and the third metal ion has been coordinated through the N atoms of oxime groups of two ligahd molecules. The third oxa-group cannot take part in complex formation because of steric hinderance. The H'-n.jn.i~~v IX a spectrum of (LH^Pd)^ shows the presence of aromatic (7.3-6.8 ppm) and aliphatic protons (3.5-3.3 ppm). Pd(II) complex is diamagnetic showing that all three metal ions are in square-planar fields. In the i.r. spectrum of (LH)2(U02)3/ V(0=U=0) absorption is at 910 cm`1 as a strong band. These complexes are likely to possess the structure given below : o VI I i 0- M 0 The formation of mononuclear or tri-nuclear complexes with certain transition elements shows that two methylene groups havw changed some features of Lh/. A similar macro- cyclic vie-dioxftme which lacks only two methylene groups, namely r-ibenzoCe, n]-2, 3-bis ( hydroxy imino ) -l,4-diaza-7, 10, 13- triox< -2,3, 8,9, 11, 12-hexahydrocyclopentadecine, formedmono-nuclear complexes with various transition metal ions. The methylene groups which affect the symmetry and distort the planar structure of the macrocycle also enables the formation of complexes with transition metal ions of suitable radii.