İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Kimya Anabilim Dalı
3,5-bis(triflorometil)fenoksi grupları içeren simetrik ve asimetrik çinko ftalosiyaninlerin sentezi ve karakterizasyonu
Synthesis and characterization of symmetric and non-symmetric zinc phthalocyanines with 3,5-bis (trifluoromethyl)phenoxy groups
Ftalosiyaninler (Pc) eşsiz optik, elektronik, katalitik ve yapısal özellikler gösteren bir bileşik sınıfıdır. Bu özellikler sensör, sıvı kristal, katalizör, fotodinamik terapi ve nonlineer optik gibi pek çok farklı bilimsel ve teknolojik alanlarda büyük bir ilgiye sebep olmuştur. Sübstitüe olmamış ftalosiyaninlerin organik solventlerde çözünürlüklerinin olmaması onların uygulama potansiyellerini kısıtlamaktadır. Ftalosiyaninler geniş konjuge π elektron sistemine sahiptir ki bu özellikleri π istiflenmesine (agregasyon) sebep olmaktadır. Böylece moleküller arası mesafenin azalmasına paralel olarak bileşiğin çözünürlüğü de azalmaktadır. Ftalosiyaninlerin çözünürlüğü alkil, fenoksi gibi grupların periferal pozisyonlara ilave edilmesiyle arttırılabilir. Çünkü bu sübstitüentler moleküller arası mesafeyi arttırmaktadır. Ftalosiyaninlerin bir diğer özelliği yapılarında aynı yada farklı sübstitüentler bulundurmalarıdır. Bu durumda simetrik ve asimetrik ftalosiyaninler meydana gelir. Farklı sübstitüentlerin kullanımı ftalosiyaninlerin elektronik yapısını değiştirebilir ve potansiyel uygulama alanlarını arttırabilir. Çalışmanın ilk kısmında 4,5-bis(3,5-bis(triflorometil)fenoksi)ftalonitril bileşiği 4,5-dikloroftalonitrildeki iki klor grubunun 3,5-bis(triflorometil)fenol yapısındaki hidroksi gruplarıyla yer değiştirmesiyle 120 oC de DMSO içerisinde N2 atmosferinde hazırlanmıştır. Bu reaksiyonda potasyum karbonat baz olarak kullanılmıştır. Bu dinitril türevinin susuz ZnCl2 varlığında DMAE içerisinde 135 oC de 24 saatte gerçekleşen siklotetramerizasyonuyla simetrik çinko ftalosiyanin elde edilmiştir. Çalışmanın ikinci kısmında 4-(3-hidroksi-3-metil-1-bütinil)ftalonitril bileşiği literatüre göre hazırlanmıştır. Bu ftalonitril türevi ve 4,5-bis(3,5-bis(triflorometil) fenoksi)ftalonitril kullanılarak susuz ZnCl2 varlığında DMAE içerisinde 120 oC de azot atmosferinde birinci asimetrik çinko ftalosiyanin sentezlenmiştir. Ardından sodyum hidroksit varlığında toluen içerisinde 110 oC de ikinci asimetrik çinko ftalosiyanin reaksiyonu yürütülmüş ve son olarak Sonogashira coupling reaksiyonu kullanılarak üçüncü asimetrik çinko ftalosiyanin elde edilmiştir. Sonuç olarak bu çalışmada yeni bir ftalonitril türevi, bu ftalonitrilden bir simetrik çinko ftalosiyanin ve üç tane de asimetrik çinko ftalosiyanin sentezlenmiştir. Bileşiklerin karakterizasyonu IR, UV-Vis, NMR, GC-MS ve MALDI-TOF teknikleri kullanılarak yapılmıştır.
Porphyrins (P) and phthalocynines (Pc), the two main classes of the tetrapyrrolic macrocycles, differ basically as the porphyrins are formally derived from the porphine molecule, whereas phthalocyanines are constitutionally tetraazatetrabenzo analogues of porphyrins since they have a porphyrazine –type central core with N atoms bridging the pyrrole rings instead of the CH groups present in the porphyrin sceleton. Porphyrins are either naturally occuring molecular systems or original synthetic products, whereas phthalocyanines derive exclusively from synthetic laboratory work. Phthalocyanines were discovered by chance in 1907, as an impurity during the synthesis of o-cyanobenzamide. In the following years, phthalocyanines used as dyes and pigments, also a lot of study were patented. Linstead and co-workers were pioneers to characterize the chemical structure of phthalocyanine molecule using the X-ray method. The core of phthalocyanine is capable of coordinating more than 70 elements. Different metal ions give unique character and change not only physical properties but also chemical properties. Phthalocyanines (Pcs) are an interesting class of compounds which show unequaled optical, electronic, catalytic and structural properties. These properties give rise to a great interest in different scientific and technological areas such as sensors, liquid crystals, catalysis, photodynamic therapy, and nonlinear optics. The field of nonlinear optics (NLO) has been developing for a few decades as a promising field with important applications in the domain of photoelectronics and photonics. NLO materials can be used to manipulate optical signals in telecommunication systems and other optical signal processing applications. NLO activity was first found in inorganic crystals, such as LiNbO3, but the choice of these materials is rather limited. Also, most of them have either low NLO responses or important drawbacks for processing into thin films and being incorporated into micro-optoelectronic devices. By the mid-1980s, organic materials emerged as important targets of choice for nonlinear optical applications because they exhibit large and fast nonlinearities and are, in general, easy to process and integrate into optical devices. Moreover, organic compounds offer the advantage of tailorability: a fine-tuning of the NLO properties can be achieved by rational modification of the chemical structure. Finally, they are ideal to achieve the ultimate goal of device miniaturization by going into the molecular level. Strong nonlinearities in organic molecules usually arise from highly delocalized π-electron systems. Phthalocyaninesm(Pcs), with their extensive two-dimensional 18 π-electron system, fulfill this requirement and have been, indeed, intensively investigated as NLO materials. They exhibit other additional advantages, namely, exceptional stability, versatility, and processability features. The architectural flexibility of phthalocyanines is well exemplified by the large number of metallic complexes described in the literature, as well as by the huge variety of substituents that can be attached to the phthalocyanine core. Furthermore, some of the four isoindole units can be formally replaced by other heterocyclic moieties, giving rise to different phthalocyanine analogues. All these chemical variations can alter the electronic structure of the macrocyclic core, and therefore, they allow the fine-tuning of the nonlinear response. Applications of unsubstituted phthalocyanines are limited owing to their insolubility in most organic solvents. Phthalocyanines have a large conjugated π-system which induces π-stacking (aggregation) between planar macrocycles, which causes reduction in the distances between the macrocycles. The solubility of phthalocyanines can be enhanced by introduction of substituents such as alkyl or phenoxy on the periphery of the molecule, because these substituents raise the distance between the stacked phthalocyanines. In addition, phthalocyanines can have same or different substituents in their structures and thus they are named as symmetric or non-symmetric phthalocyanines. Using different substituents can alter electronic structures of phthalocyanines and this situation enhances potential application areas. In the first part of the study, 4,5-bis(3,5-bis(trifluoromethyl)phenoxy)phthalonitrile was prepared from 1,2-dichloro-4,5–dicyanobenzene by displacement of the two chloro groups with the OH function of the 3,5-bis(trifluoromethyl)phenol at 120 oC in DMSO under N2 atmosphere. In this reaction, potassium carbonate was used as a base. Cyclotetramerization of this dinitrile derivative in the presence of anhydrous metal salt ZnCl2 at 135 oC in DMAE, under a nitrogen atmosphere gave symmetric zinc phthalocyanine. In the following part, 4-(3-hydroxy-3-methyl-1-butynyl)phthalonitrile was prepared as in the literature. By using this derivative and 4,5-bis(3,5-bis(trifluoromethyl) phenoxy)phthalonitrile, the first unsymmetrically substituted zinc phthalocyanine was prepared in the presence of anhydrous metal salt ZnCl2 at 135 oC in DMAE under N2 atmosphere. Afterwards, the synthesis of second unsymmetrically substituted zinc phthalocyanine was carried out in the presence of sodium hydroxide in toluene at 110 oC. Finally, the third unsymmetrically substituted zinc phthalocyanine was obtained by using Sonogashira coupling reaction. When we look at the characterization of 4,5-bis(3,5-bis(trifluoromethyl)phenoxy) phthalonitrile, In the IR spectrum of this compound, stretching vibrations of H– Ar, C≡N, Ar C=C, Ar–O–Ar, C-F appeared at 3062, 2239, 2939, 1596, 1125, 1362 cm-1 respectively. In the 1H-NMR spectrum of this compound, protons were observed at 7.77, 7.48, 7.38 ppm. In the 13C NMR spectrum of this compound, carbons were observed at 155,10 (aromatic C), 149,71 (aromatic C), 134,13 (aromatic C), 125,31 (CF3), 123,42 (aromatic C), 119,29 (aromatic C), 118,59 (aromatic C), 113,91 (CN), 113,68 (aromatic C) ppm. In the 19F NMR spectrum of this compound, fluorides were observed at -63.09 ppm. In the mass spectra of this compound, molecular ion peak were observed at m/z = 584. In the IR spectrum of symmetric zinc phthalocyanine, stretching vibrations of Ar C=C, Ar–O–Ar, C-F appeared at 1611, 1127, 1369 cm-1 respectively. In the 1H-NMR spectrum of this compound, protons were observed at 9.17, 7.64, 7.49 ppm. In the mass spectra of this compound, molecular ion peak were observed at m/z = 2399 [M]+. In the 1H-NMR spectrum of three unsymmetrically substituted zinc phthalocyanine, when aromatic protons were observed between 9.4 and 7.4 ppm, aliphatic protons of first unsymmetrically substituted zinc phthalocyanine were observed at 1.8 ppm. In the mass spectra of these compound, molecular ion peaks were observed at m/z = 2026, m/z = 1969 and m/z = 2091 respectively. In conclusion, a new phthalonitrile derivative and corresponding one symmetric zinc phthalocyanine and three non-symmetric zinc phthalocyanines were obtained in this study. Characterization of all compounds involved a combination of methods including IR, UV-Vis, NMR, GC-MS and MALDI-TOF.