Taç eter substitue yeni ftalosiyaninler

Abstract

ÖZET Ftalosiyaninler genellikle ftalonitril ve bunların çeşitli türevlerinden (örneğin ftalimid, ftalik asit vb.) metalsiz olarak ve metal tuzlanyla tercihen yüksek sıcaklıklarda metalli olarak elde edilmektedirler. Ayrıca o-pozisyonunda halojen içeren çeşitli aromatik bileşikler de CuCN ile reaksiyona sokulursa ftalosiyanin oluşmaktadır. Elde edilen ftalosiyaninler genellikle mavi renkli, yüksek ısıya ışığa ve asitlere karşı dayanıldı, fakat çözünürlüğü çok az olan bileşiklerdir. Bu çalışmada organik solventlerde çözünebilen ftalosiyanin sentezi için yeni bir başlangıç maddesi olan l-{([Benzo-15-crown-5]-4'yl)tiya}-3,4-disiyano benzen (1) sentezlenmiş ve buradan da ilgili metal tuzlanyla yeşil renkli nikel, kobalt, balar, çinko, kurşun, kalay (kahverengi) ve hidrokinonla metalsiz ftalosiyaninler elde edilmiş, ayrıca Nikel ftalosiyaninden yapılan Palladyum kompleksi denemesi de başarılı olmuştur. Elde edilen yeni maddelerin yapılan Elementel Analiz, İR, UV/Vis ve NMR yöntemleriyle aydınlanmıştır.

SUMMARY NOVEL PHTHALOCYANINES WITH CROWN ETHER SUBSTITUENTS Since their early synthesis this century, phthalocyanines have established themselves as blue and green dyestuffspar excellence. They're an important industrial commodity (output 45.000 tons in 1987) used primarily in inks (especially ballpoint pens), coloring for plastics and metal surfaces, and dyestuffs for jeans and other clothing. More 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 ramifications. Thus future potential uses of metal phthalocyanines, currently under study, include 1) Sensing elements in chemical sensors. 2) Electrochromic display devices. 3) Photodynamic reagents for cancer therapy and other medical applications. 4) Applications to optical computer read/write discs, and related information storage systems. 5) Catalysts for control of sulfur effluents 6) Electrocatalysis for fuel cell applications. 7) Photovoltaic cell elements for energy generation 8) Laser dyes 9) New red sensitive photocopying applications 10) Molecular metals and conducting polymers. In addition to their extensive use as dyes and pigments, phthalocyanines have found wide applications in catalysis, in optical recording, in photoconductive materials, in photodynamic therapy and as chemical sensors. For this broad range of applications the stable phthalocyanines core should be amenable to modifications which can be accomplished either by changing the central metal ion or by adding functional groups on the periphery. By a judicious choice of substituents with suitable donor groups on the periphery, one can direct the phthalocyanine interactions with metal ions or with one another; the -vi-consequences of these phenomena will appear in affecting the ordering of molecular assemblies in the solid state as well as in solution. Drastic changes occur in the absorption spectra and photophysical properties when strongly conjugated macrocycles such as phthalocyanines are forced to lie in face-to-face conformations. Although phthalocyanines with N- and O-donor substituents have been frequently encountered, those with thioether moieties are rather few. The latter group contains essentially products obtained by the cyclotetramerization of thioether substituted phthalonitriles which themselves have been derived by nucleophilic displacement reactions of dinitriles. Physical and chemical properties of soluble phthalocyanines have recently `attracted much attention from material chemists for their potential use in semiconducting materials, nonlinear optics and,, other optical devices. At the same time, since they effectively absorb in the lower energy region of visible light, they have found extensive application as photoconductors in optical recording materials as well as photosensitizers in photodynamic therapy. The advantage of using soluble phthalocyanines for these applications, incontrast to the insoluble parent phthalocyanines, is the possibility to reach high purification degrees by column chromatography or crystallization. Incorporation of macrocyclic groups such as crown ethers, tetraaza or diazatrioxa macrocyle onto the periphery of phthalocyanines has enhanced the solubility of these compounds. At the same time, additional binding sites for different kinds of ions have been provided. The macrocyclic substituents also bring about novel features such as ion channel and mesophase formation when the macrorings are integral parts of the inner core by way of enhancing the planarity of the molecules. A flexible bridging group between the core and the macro-substituents, on the other hand, provide the possibility of intramolecular or intermolecular interactions of macrocyclic groups as encountered with tetra- or octa- (oxymethylbenzo-15-crown-5) substituted phthalocyanines. As part of our continuing interest in synthesizing novel compounds carrying multi-donor sites suitable for binding different ions at the same time we have synthesized a new phthalocyanine carrying four benzo-15-crown-5 substituents through thioether bridges. It is also expected to be a new contribution to the thia-substituted phthalocyanines which are rather few in the literature and which recently receives interest for the shift of their intense Q absorptions to the longer wavelengths. At the same time, alkali ion binding properties of the crown ether substituents will be evaluated in comparision with the similar compounds. -vu-In the present work, we., have synthesized for the first time l-{[(benzo-15- crown-5)-4'yl]thia}-3,4-dicyanobenzene (1). The key step of the synthetic route to prepare phthalocyanines carrying thia-bridged benzo-15-crown-5 moieties relied upon the well-known base-catalyzed aromatic nitro displacement of 4- nitrophthalonitrile with 4'-mercapto-benzo-15-crown-5, which was also itself obtained through a multi-step reaction. Anhydrous ^COj was the base of choise and DMSO was the solvent. The reaction was made to proceed by us- ing the carbonate ion as the nitro-displacing nucleophile. (Scheme 1) <: P ^XJ + ^ACN DMSO < o4^f« *S?^CN (Scheme 1) Synthesis of l-{[(benzo-15-crown-5)-4'-yl]thia}-3,4-dicyanobenzene Conversion of l-{[(benzo-15-crown-5)-4'-yl]thia}-3,4-dicyanobenzene to phthalocyanine was accomplished through the usual cyclotetramerization reactions in the presence of a reductant and/or metal salt; that is, hydroquinone was used to obtain metal-free derivative (2) while the metal salt (NiCl2, CoCl2, Zn(OAc)2 or SnCy and a suitable solvent such as quinoline, ethylene glycol or 1-chloronaphthalene were required for the metal phthalocyanines 3_, 4, §., I- (Figure 1) -vui-!2 3 4 5 6 7 8 M 2H Ni` Co` Cuu Zn` Pb` Sn* CL (Figure 1) Novel Phthalocyanines carrying thia-bridged benzo-15-crown-5 moieties Cu-derivative was prepared by the reaction of 1, CuCl, and urea at 160- 170° C. Portionwise addition of PbO into melted I gave the lead phthalocyanine. A common feature of all the phthalocyanines 2-§ is their solubility in various solvents including chloroform, dichloromethane, etc. as in the case of similar compounds with bulky or macrocyclic substituents. As a consequence of the tetra-substitution, a mixture of isomers has been obtained which should be noted as a disadvantage while it causes broadening in both the UV-Vis and H NMR spectra. The IR spectra of phthalocyanines with tetra(thia-bridged crown ether) substituents 2-§ are in agreement with the data for similar macrocycles. Aside from the bands of crown ether groups at 1140-1260 cm there are signals -K-resulting from the aromatic ring. Especially important is the band at 3300 cm for 2, which is assigned to NH groups of inner core. In the H NMR spectra, the detected signals were easily assigned to aromatic protons around 7-9 ppm and the etheral protons around 4 ppm. In addition, the inner core protons of 2 show a broad signal at -4.6 ppm similar to what has been observed for other metal-free phthalocyanines. The C NMR spectra of the dicyano-compound (1) and the phthalocyanines 2, 3_, §., 2 and I have been recorded. While the aliphatic etheral carbons appear around 69-71 ppm, the aromatic carbons are assigned to literature data and the previous results obtained from similar compounds. As in the case of many other substituents phthalocyanines, these with four crown ether substituents 2-Ş exhibit an important tendency to aggregate in solution. As a, consequence, their absorption spectra are highly depended upon the solvenj-lused. Invery dilute chloroform solutions, their Q-band absorptions are rather narrow indicating the presence of only monomelic species are likely to be present. At higher concentrations or with solvents of higher protic character, aggregates are formed. The electronic spectra show a doublet in the Q band region at 718 nm and 689 nm typical for metal-free phthalocyanines. The divalent metal phthalocyanines give a single Q band as a result of the D4h symmetry. For all of the phthalocyanines the effect of thia-substitution is the shift of these intense Q bands to higher wavelengths when compared with the unsubstitued or alkyl substituted derivatives. The high tendency of crown ethers to bind alkali or alkaline earth metal ions provides an efficient way to decide whether inter-or intra-molecular interaction is present among the crown ether units when these ions are added into solution. For this purpose, the tetra-(thia-bridged-crown ether) substituted phthalocyanine 2 was dissolved in chloroform/methanol and the solution of metal salt in the same solvent mixture was added gradually. As encountered in the case of phthalocyanines with four crown ether substituents as integral parts, by the immediate effect observed by concentration of the salt is a decrease in the intensity of the Q band at 679 nm attributed to the monomelic species with a simultaneous increase at 637 nm due to oligomeric aggregates. Blank tests carried out by the addition of similar amounts of ethanol did not cause any appreciable change in the spectra. Hence, sandwich type adduct formation among crown ether units is causing the aggregation of phthalocyanine molecules which is a consequence of intermolecular interaction among the crown ether groups. The alkali ion binding capability of the crown ether groups bound to phthalocyanine core through thia-bridges was tested by solvent extraction of alkali metal picrates from water to chloroform. The results summarized in Table A.2 clearly indicates that the highest affinity has been observed for potassium -x-ion with all phthalocyanines 2-§. The influence of the metal ion in the inner core of the phthalocyanine molecule is noteworthy, but the higher values encountered especially with Pb and Sn, which are known to disturb the planarity of the molecule due to their high volume, do not enable us to predict any effect related to planarity of the phthalocyanines. The electrical properties of phthalocyanines having completely conjugated 18-11 electrons are attracting considerable interest in recent years for various device applications. Metal-free and transition metal phthalocyanines 2.-Ü were investigated with respect to their d.c. conditivites. For this purpose, gold/phthalocyanine/gold sandwiches were prepared by coating the pressed pellets of microcrystaliine powders with gold in high vacuum. The 6 values given in Table A.3 reveaRhat the order of 10 - 10 S.m_1 is in the semiconductors level as expected for the phthalocyanines with bulky peripheral substituents. Various treatments including partial oxidation have been tried to enhance the conductivity of phthalocyanines. Here we used the insertion of additional metal ions complexed to thia-donors and the conductivity of this product 3.2PdCL was increased to 7.2x10 S.m`. This increase is comparable with those obtained by partial oxidation with / or NOBF4. The thermal stability of the phthalocyanines were evaluated by thermogravimetric analysis (tga). The initial and main decomposition temperatures given in Table A.3 indicate their high stability with the increasing initial decomposition temprature order of Cu < Pb < SnCl2 < Ni _ Co ~ Zn <2H. Although no correlation can be established among the metal phthalocyanines, the highest value occuring for the metal-free derivative might be taken as an indication of catalytic properties of the metal ions for the decomposition processes. The low value given for the Pd complex of nickel phthalocyaninate also confirms this effect. -XI-BÖLÜM 1.GİRİŞ Koordinasyon kimyası; anorganik kimyanın temel alt gruplarından birisidir. Koordinasyon bileşikleri veya metal kompleksleri genellikle merkez atomu olarak bir metal içeren ve ionlar veya moleküllerin bu metal atomunu çepeçevre sardığı bileşiklerdir. Kompleks, çözücüde kısmi bir dissosiasyona uğramasına rağmen bozulmaz. Bu nedenle koordinasyon bileşikleri kimya endüstrisinde çok büyük rol oynar. İlk bilinen koordinasyon bileşiği Prusya mavişidir. [KCN. Fe (CN)2 Fe (CN)3]. Koordinasyon bileşikleri ile ilgili ilk modern çalışmalar Werner ve Jorgensen üe başlar. Werner 1913 yılında Nobel kimya ödülünü alan ilk inorganik kimyacıdır. Werner'in bu konuda 3 yaklaşımı vardır [1]: 1) Elementlerin çoğu 2 tip valens sergilerler: a) Birincil valens : Oksidasyon derecesine tekabül eder. b) ikincil valens : Koordinasyon sayışma tekabül eder. 2) Tüm elementler birincil ve ikincil valenslerini doyurmaya çalışırlar. 3) İkincil valens uzayda yönlendirilmiş durumdadır. Koordinasyon numarası; metal atomuna direkt olarak yönlenmiş atom veya moleküllerin sayısıdır. Bu atom veya moleküllere `ligand` denir. Ligand yalnızca bir donör atom içeriyorsa tek dişli ligand olarak adlandırılır. Örneğin CO ve CT bu tür ligandlardır. liganda birden fazla atom yönlenmişse `çok dişli ligand` olarak adlandırılır. Bu tür ligandlar merkezdeki metal atomuna birden çok koordinasyon atomuyla yönleniyorlarsa bunlara `şelat yapıcı ligandlar` denir. Bu durumda metal içeren ftalosiyaninler de bir şelat bileşiği olarak düşünülebilir. Ligandlar; anyonik, nötral veya nadiren katyonik olabilir. Klasik