Yeni tetrapirol türevlerinin sentezi
The synthesis of new tetrapyrrol derivatives
Yazar: BEHİCE ŞEBNEM SUNGUR
Danışman: PROF. DR. AHMET GÜL
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Kimya Ana Bilim Dalı
Derece: Yüksek Lisans, 1999
Konu: Kimya = Chemistry
Dizin: Sentez = Synthesis ; Tetrapirol = Tetrapyrrol

Özet:
yeni tetrapirol türevlerinin sentezi ÖZET Bu çalışmada yeni bir düzlemsel bis (tetrapirol) türevi sentezlenmek istenmiştir. Bu yapıya ulaşmak için öncelikle iki adet 1,2-dmitril grubu olan bir siklofan elde edilmiştir. Bunun için ditiyomaîeonitril disodyum tuzu ile p-p'-dibromoksilen reaksiyona girmiştir. NMR verileri 7,24 ppm'de aromatik protonları, 4,2 ppm'de S-CFfe'ye ait protonları göstermektedir: Elemente! analiz sonuçlarında teorik ve pratik hesaplar Dİrbirine çok iyi uyum. sağlamaktadır. Maddenin İR spektrumunda 2238 cm"1 'de tek bir CN pikinin olması, (maddenin oligomerik olmadığını yani simetrik D^ yapısında olduğunu) benzen halkalarından kaynaklanan aromatik protonlar* ve SGH2 protonlarının bulunması istenilen yapıyı destekler. İki ftalonitril türevinin kombinasyonu olarak ele alacağımız bu yapıların sentezinde mutlaka bir izomer karışımı eMe edilecektirJ A: IB yapısında bir ürün istendiğinde A:B oram 25:1 gibi çek yüksek alındığında izomer sayısı azaltılabilirBunian göz önünde tutarak model bileşikte İmmol bis(hegziItîyo)maleonitrîl île 25 mmol ftalonitril reaksiyona: girerek: 3:1 asimetrik yapı sentezlenir. Daha sonra yine ftalonitril ile siklofan yapı polimer oluşumunu engellemek amacıyla 25:1 oranında alınarak hedeflenen- bis(tetrapirofy türevr sentezienmiştir. Metaisiz olarak elde edilmesinin en büyük avantajı, metalsiz ftalosiyaninlerin bilinen çözücülerde çözünmeyip ortamda çökerek ayrılmasıdır. Model bileşiğin UV/VIS spektrumunda. Bu maddenin UV spektrumunda simetri D^'tan Cîv ye dönüşerek Q bandından yanimaya sebep olmuştur. İR spektrumunda da Ar-CH2 1er yanında alifatik CH2 lerin gözükmesi istenilen, yapının oluşumunu destekler. Dimerik ürün NMR verileri 7,24 ppm'de aromatik protonları, 4,2 ppm'de S- CHs'ye ait protonları göstermektedir: Elementel analiz sonuçlarında teorik ve pratik hesaplar birbirine çok iyi uyum sağlamaktadır. Maddenin İR spektrumunda 2238 cm"1 'de tek bir CN pikinin olması, (maddenin polimerik olmadığını yani simetrik D-^ yapısında olduğunu) benzen halkalanndan kaynaklanan aromatik protonları ve SCH2 protonlanmn bulunması istenilen yapıyı destekler. vııı

Abstract:
THE SYNTHESIS OF NEW TETRAPYRROL DERIVATIVES SUMMARY Tetrapyrrol derivatives are- stable compounds which are synthesized by cyclotetramerization of unsaturated 1,2-dinitrile reactants. If tetranîrile derivatives are used as reactans, then a planarnetwork polymer is obtained. Recently this kind of complexes are investigated for phthdocyanines extensively. While phthalonitrile and derivatives yield monomerie^ phthakmitriles,the derivatives of 1,2,4,5- tetracyonobenzene or 4.5,4',5'-tetracyanodibenzo-18-crown-6 yield network algomenc phthalocyanmes: The complexes which we consider as dinuclear phthalocyanines require the conbination of these two kinds of reactants and there are only a few examples hr the- literature. The-condensation of two unsaturated 1,2 -dicyano-- derivatives wilt cause a reaction mixture which contains six different isomers. fnf 4AjOB 3A:1B \ 2A;2B 2A;2B(çapraz) 1A:3B 0A:4B Figure 1 : 6 different isomers Here A and B show different 1,2-dinitrile stems. Even in the case of using stoichiometric amounts for a certain isomer, the product is a mixture. Taking the ratio of A/B as 25/1 the mixture of isomers can be reduced to a level which contains too many 4 A: OB isomers with sufficient amount of 3 A: IB. In this study, a new porphyrazine; phthalocyanine dinuclear complex linked by a cyclophane bridge and a model compound which can be considered as a half of the dimer are systhesized. IXFigure 2 : Tetraazatribenzobis(hegzylthio)porphyrine As a model compound, tetraazatribenzobis(hexylthio)porphyrine has been systhesized through the reaction of phthalonitrile with l,2-bis(hexythio) maleonitrile. In order to prevent the formation of all six products described above, phthalonitrile is taken in excess. (25 mmof phthalonitrile 1 mmol l,2-bis(hexylthio) maleonitrile). Under these conditions, the product is mainly composed of Mg-phthalacyanine and the desired 3:1 product Since the solubility of KfePc in common organic solvents is almost negligible, the reaction product is converted into metal-free Pc by treatment witirHifluoroacetic acid. In the UV- VIS spectrum, the change of the symmetry from Da to Ctv results with further splitting of the Q band at 656 and 708 nm. In the IR spectrum, aliphatic CH stretching vibrations at 2895 cm"1 are observed together with the aromatic CH vibrations around 3100 cm"1. \_^ V-/ Figure 3 : S4(CK)4(EN)2[2.2]PCP First of all tetracyanotetrathia cyclophane is synthesized for the dimer. For this purpose, disodium salt of dithiomaleonitrile and p,p'-dibromoxylene is reacted in stochiometric ratio. Reaction should be carried out under inert atmospfere; other vise the product is redish. Cyclophane has been synthesized both in acetone and in methanol under the same conditons. The product is dissolved in acetone but it precipitates in metinanol. At the end of 8 hours, in methanol, the reactions mixture is filtered and the precipitate is treated with 5ml of THF and filtered. The filtrate is left at 50°C overnight during which time a pure white precipitations occured with a relatively low yield. When the solvent is acetone, the product can be obtained as a light yellow needle-like crystal after recrystalization from acetone. In the ^-NMR spectrum, Ar- and S-CFfe protons appear at 7,24 and 4.7 ppm respectively. The elmentel analytical. Results closely follow the theoretical values. In the IRspectrum,there is a single peak at 2238cm"1 for CN group, which indicates the symmetric nature of the molecule. ^-J/ V-> Figure 4 : 6: l;Pc: PA dimmer Finally, the method which has been applied to obtain the model compound,tetra azatribenzobis(hexylthio)porphyrine, is used to reach the dimeric structure. As done bifore one of component ;is taken in excesses mmol of phthalonitrile and 1 mmöl oftetracyanotetrathiacyclophane. In the isolation process, the crude product is again converted into the metal -free derivative by treatment with trifluoroacetic. acid. When this mixture- of metal free derivatives is extracted with THF, the desired dimeric structure is in THF solution. Evaporation of the solvent under reduced pressure leads to the product. Because of D^ symmetry, in UV/VIS spectrum sharp spliting is observed at 654,and 690 nm. In IR spectrum IR streetching vibration of innercore N- H group is at 3285- cat1 and aromatic CH at 3029, 3080 cm"1, together with elemental analytical results, we might propose the dimeric. structure for the product. In conclusion, beside being a new member to the tetrapyrrol family, the dimeric compound will be especially interesting for supramolecuiar chemistry because of the three dimensional cavity capaple of functioning as a host for guest molecules. XI