Yeni bir çözünür ftalosiyanin sentezi

Abstract

Bu çalışmada bakır (II) tetranitroftalosiyanin sodyum sülfür ile tetraamino türevine indirgenmesinden sonra, uzun zincirli alifatik aldehidlerle kondensasyonu sonucu çözünür- bir ftalosiyanin elde edilmiştir. Ftalosiyaninler genellikle ftalanitril, ftalik anhidrit, ftalimid veya bunların sübstitüsyon ürünleri ile metal tuzları arasındaki reaksiyondan elde edilebilir. Ayrıca odihalojen içeren arornatik bileşikler ile bakır siyanür arasındaki reaksiyon diğer bir elde türüdür. Ftalosiyaninler benzen halkası üzerinde sübstitüsyon yolu ile sayısız türev oluştururlar. Ancak halka üzerinde doğrudan sübstitüsyon gelişigüzel olur. Dağılımın eşit şekilde olması için önce ftalosiyanini oluşturacak ligand sübstitüsyon reaksiyonuna sokulur, daha sonra ftalosiyanin elde edilir. Bu nedenle tetranitro bakır ftalosiyanin nitrof talikasitten çıkılarak elde edilmiştir. Ftalik anhidritten başlanarak ftalimid ve 4-nitrofta- limid literatürde açıklanan metotlarla elde edilmiştir. 4- nitrof talimid' den sodyumhidroksit ve nitrikasitli ortamda 4-nitrof talikasit elde edilmiştir. Bu çalışmada ftalosi yanin eldesi için çıkış maddesi olarak 4-nitrof talikasit kullanılmıştır. 4-nitrof talikasit amonyummolibdat, amon- yumklorür, üre ve nitrobenzenli oz-tamda kaynatılarak mavi renkli bakır (II) 4,9,16,23, tetranitroftalosiyanin elde edilmiştir. Daha sonra tetranitroftalosiyanin sodyumsül- für nonahidrat ile bakır (II) 4, 9, 16, 23 tetraaminof talosiyanine indirgenmiştir. Elde edilen ürün koyu yeşil renklidir. Asitli ortamda kompleks renginin maviye dönmesi amonyum haline dönüşen amin gruplarının halka sistemine elektron verme özelliğini kaybetmesinden kaynaklanır. Yalnız dimetilf ormamid, dimetilsulf oksit, dimetilasetamid, piridin gibi ap.rotik solventlerde berrak çözelti veren ba kır (II) 4, 9, 16, 23-tetraamin f talosiyaninden Lauril alde hit ile piridinli ortamda schLff bazı sentezlenerek çözünür yeni bir ftalosiyanin elde edilmiştir.

Coordination chemistry is the main branch of inorganic chemistry growing amazingly in the recent decades. Coor dination chemistry works on coordination compounds or comp lexes which contain a central metal atom or ion, usually a metal ion surrounded by a cluster of ions or molecules which are called Uganda. Metal ions are Lewis acids in that they can share electron pairs donated by ligands, which are therefore Lewis bases. A ligand attached directly through only one coordina ting atom (or using one coordinating site on metal) is called monodentate ligand. Those which have more than one binding sites are called bidentate^ridentate, etc* They are also called a chelating ligand. Most transition metal ions have room to bind up to six ligand atoms. In classical coordination chemistry, the number of donor atoms (with one Lewis base electron pair per donor atom) bound directly to the central metal defines the coordination number. The ligand directly bound to the metal are said to be in the inner coordination sphere, and the counter ions, that balance out the charge remaining on the complex after the coordination number of the central metal has been satis fied, are said to be outer sphere ions. Cordination compound containing macrocyclic ligands have been known and studied since the beginning of this century; however, until quite recently the number and variety of these compounds, were limited. The development of the field of bioinorganic chemistry has been an important factor in spurring the growth of interest in complexes of macrocyclic compounds since it has been recognized that many complexes containing synthetic macrocylic ligands may serve as models for biologically important species which contain metal ions in macrocyclic ligand environment. The study of the proper ties and sythesis of macrocyclic complexes may have important concequences for biochemistry as much as many important com pounds in living system such as chlorophyll, hemoglobin etc., contain macrocyclic porphyrin rings attached to metal atoms. Phthalocyanies are an important group of macrocyclic complexes known for over 60 years. Since of this cl from both view. In detailed c has arisen has led to and other- pounds. then the un ass of coord the pactical recent times oordination The great a veritable, naturally oc ique physical and chemical properties ination compounds have been exploited as well as the theoretical point of a compelling reason to study the chemistry of metal lophthalocyanines activity in bioinorganic chemistry avalanche of week an. metal lop orphyr ins curing macrocylic coordination corn- There are many common points in structural characteris tics between porphyrins and phthalocyanines. Phthalocyanihesare macrocyclic molecules containing four isoindole units, which are synthetic analogs of naturally occuring porphyrins deri ved from the porphin ring system (Fig.l) Porphin Fig 1: Porphin (ring system) Copper Phthalocyanines and Its synthetic analog. It is confirmed that in the formation of macrocyclic compounds cations play an important role for the yield of the reaction. This fact is called "template.effect", which reflects the controlling influence of the metal ion in a particular synthesis. The macrocyclic structure in phtha locyanines is actually formed by the template effect of a metal ion to link four phthalonitrile molecules. Phthalocyanine molecules have totally eigtheen hyd rogen atoms. Two central hydrogen atoms are not respon sive to any reaction except substitution with metal atoms in complex formation; for instance, all attempts to alkylate or to acylate these hydrogen atoms have failed. Other sixteen hydrogen atoms are attached to its outer benzenoid rings. These hydrogen atoms can be replaced with appropriate substituents. vx Intense colQr and great stability are two striking properties of both the natural.porphin derivatives and the synthetic phthalocyanines. They are highly crystalline, vary in colo.r from reddish blue to bluish green and are extremely stable. Copper phthalocyanine for instance sublimes without decomposition at 550-580 C, dissolves in concentrated sulphuric acid and is recovered unchanged upon dilution. The copper compound is reddish in shade and can be obtained in various crystalline or noncrystalline forms with unique physical characteristics by applying different reaction conditions and treatments. The polymorphism of CuPc can be observed in its «*,p, *",£,£., forms which exhibit different red shades ana crystalline properties - Most of the unsubstituted phthalocyanines can exist in two crystalline modifications, which differ from each other in solubility, shade and thermodynamic stability. The metastable form is termed the "alpha" modification, the more stable form is termed the "beta" modification. The two forms are readily identified by their x-ray diffrac tions patterns. The more stable beta modifications of the phthalocyanine pigments are produced when they are treated with organic solvents, the rate of phase change being dependent upon the temperature and the nature of the solvent. The alpha forms revert spontaneously to the beta modifications when they are heated to 200 C, or when they are exposed, even at room temperature, to many organic sol vents, particularly those of aromatic character. The size of the metal atom has an improving effect on the stability of the molecule. Copper fits reasonably well into the center cavity, therefore it is very stable. When the atomic radii of metals are considerably larger or smaller than 1.35 A (e.g., manganese and lead) the metal atoms are more readily removable from the phthalocyanines. On the other hand the atomic radii do not have a significant effect oh the planar symmetry in the crystals, owing to the structural stability of the framework of the phthalocyanine molecule which makes the metals conform to its steric require ments. Phthalocyanines can be prepared via two general proce dures, namely the "nitrile" method and the "anhydride" method. Substituted phthalonitriles often must be prepared through the sequence, dicarboxylic acid-»anhydride_, imide_, amide-» nitrile. The anhydride metod has the advantage over the nitrile method that it involves the use of the readily accessible phthalic acid, anhydride and imide. vix idealized coordination spheres for metal lophthaloc- yanines are shown in figure 2. Figure 2. idealized coordination spheres for metal lopht- halocyanines*. 6-Coordinate tetragonal (left), 5-coordinate square phramidal (center), 4-coordinate square planar (right). The ring with four N donors represents the phthalocyanine ring. Since their synthesis early in this century, phthaloc- yanines have established themselves as blue and green dyes- tuffs par excellence. They are an important industrial commodity used primarily in inks, coloring. plastics and metal surfaces, and dyestuf f s jforrjaans for and other clothing. More recently their use as the photoconducting agent in photocopying machines heralds a resurgence of interest in these species. In the coming decade, their commercial utility is expected to have significant ramifica tions. Thus future potential uses of metal phthalocyanines include sensing elements in chemical sensors, electrochromic display devices photodynamic reagents for cancer therapy and other medical applications, applications to optical compu ter read/w-^-i-te discs, and related information storage systems,.catalysts for control of sulfur effluents, electrocatalysis for fuel cell applications, photovoltaic cell elements for energy generation, laser dyes, new red-sensitive photocopying applications, liquid crystal color display applications and molecular metals and conducting, thermallystable polymers, ih.recent years there has been a growth in the number of laboratories exploring the fundamental academic aspects of phthalocyanine chemistry. Pthalocyanine and its metal derivatives are insoluble in water and most organic solvents. But the solubility can be altered by substituting suitable functional groups in vm the peripheral benzene ring of the phthalocyanine struc ture. Among the thermally stable soluble phthalocyanine compounds, amine grops substituted metal phthalocyanine derivatives are found to be promising. The amine deriva ' - tives of metal phthalocyanines have been previously synthe sized mostly for the preparation of inks, dyes and pigments, The procedures described often give impure compounds and these compounds have not given clear solutions in aprotic solvents. Ah '.efficient method was developed for the synt hesis of analytically pure metal (II) 4, 9,16, 23-phthaloc- yanine tetraamines. The aim of this study is to synthesize a new soluble phthalocyanine derived from copper (II) 4, 9, 16,23-tetraamino phthalocyanine through schiff base reaction with long chain paraf inic aldehydes. The first step is the synthesis of copper (II) 4,9,16, 23 - tetranitrophthalocyanine. Tetranitrophthalocyanine is prepared from the substituted intermediate, 4-nitrophthalic acid. Its reaction with copper sulfate pentahydrate in the presence of ammonium chloride, ammonium molybdate and urea gave the product. It is not possible to nitrate the phtha locyanine directly by nitric acid since all phthalocyanines are attacked by strong oxidizing agents. The second step is the synthesis of copper (II) 4,9,16, 23-tetraamino phthalocyanine. The suitable way to prepare this product is the reduction of tetranitrocopperphthaloc- yanine. Nitrophthalocyanine can be reduced with sodium sulp hite, sodium hydrosulphite or stannous chloride -jin the presence strong acid. In this work tetra ratro phthalocya nine was reduced in the presence sodium sulfide nonahydrate. Tetraaminocopper phthalocyanine is deep green and insoluble in common organic solvents. This product gives clear solu tions in aprotic solvents such as.> dimethyl sulphoxide, dimethylf ormamide and dimethylacetamide. Its colour turns into blue by the action of acid as a.result of decrease in the electron density due to the salt formation. The third step is the synthesis of schiff base of aminophthalocyanine. This condensation is carried out with lauryl aldehyde in pyridine. After evaporation of the solvent, the product was isola ted by dissolving in chloroform and further precipitation with ethanol. The yield of the reaction was about 80 %.The solubility of the productiri chloroform determined spectrop- hotometrically is about İ0"2 m. xx A clear evidence of condensation reaction is the IR spectrum of the product which indicates., the disappearence of primary amino groups around 3300 cm and the appearen- ce of intense new C-H stretching vibrations of alkyl chains around" 2800-3000 cirri The electronic spectrum of the product in chloroform shows intense Q band of the phthalocyanine core around 670 nm,B bands around 3 50 nm. Etg:.3.