Yeni ferrosenil naftokinon bileşiklerinin çoklu sensör özelliklerinin incelenmesi: Organik solventlerde su tayini ve seçici katyon bağlama
Investigation of multisensor applications of new ferrocenyl naphthoquione compounds: Determination of water in organic solvents and selective cation binding
Yazar: METİN DAĞDEVREN
Danışman: PROF. DR. İSMAİL YILMAZ
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Kimya Ana Bilim Dalı
Derece: Doktora, 2016
Konu: Kimya = Chemistry
Dizin: Benzotaç eter = Benzocrown ether ; Spektroelektrokimya = Spectroelectrochemistry

Özet:
Tez konusu üç genel aşamadan oluşmaktadır: (1) Yeni ve orijinal nitelikte çok-fonksiyonlu taç eter grupları içeren ferrosenil naftakinon bileşiklerinin (4a, 4b) sentezi, (2) Sübstitue ferrosenil naftakinon bileşiklerine dayalı eser miktarda su tayini için (aprotik solventlerde) yeni voltametrik yöntem geliştirilmesi, (3) Taç eter grupları içeren ferrosenil naftakinon bileşiklerinin seçici katyon-bağlama özelliklerinin incelenmesi. 
Tez çalışmasının birinci aşamasında orijinal nitelikte taç eter gruplu (benzo-15-taç-5 ve benzo-18-taç-6) ferrosenil naftakinon bileşikleri (4a, 4b) sentezlenmiştir. Bu bileşikler siklobütendion ve benzosiklobütendion temelli bir sentez yöntemi ile üretildi. Yeni sentezlenen ve taç eter grupları içeren ferrosenil naftakinon bileşikleri, FT-IR, 1H-NMR, 13c-NMR, kütle spektroskopisi ve elementel analiz yöntemleri ile karakterize edildi.
Tez çalışmasının ikinci basamağında sübstitue ferrosenil naftakinon bileşiklerine dayalı (3a, 3b, 3c, 3d) 7 farklı solvent (asetonitril, benzonitril, diklorometan, tetrahidrofuran, dimetilformamid, dimetil sülfoksit ve propilen karbonat) içinde eser miktarda su tayini için doğruluğu yüksek, doğrusal aralığı kontrol edilebilir ve hassasiyeti yüksek yeni voltametrik yöntem geliştirildi. Bu solventler çalışma öncesinde ultra düzeyde kurutuldu. Asit içermeyen aprotik organik solventlerde kinonlu bileşikler, elektrokimyasal olarak tersinir özellik gösteren iki indirgenme basamağına sahiptir. İlk indirgenme basamağı bir elektron alarak indirgenen monoanyon radikali (Q•−), ikinci indirgenme basamağı ise monoanyon radikalinin bir elektron daha alarak indirgenmiş formu olan dianyon (Q2-) yapısıdır. Yapılan çalışmalar monoanyon ve dianyon yapılarının (solvent ortamında) su ile hidrojen-bağı yaptıklarını göstermiştir. Ortamdaki su miktarı arttıkça monoanyona ait E1 ve dianyona ait E2 potansiyellerinin ΔE2 > ΔE1 olacak şekilde pozitif potansiyellere doğru kaydığı ve belli bir su miktarına ulaşıldıktan sonra E2 ve E1 potansiyellerinin birleştiği ve tek basamaklı iki elektronlu bir prosese dönüştüğü rapor edilmiştir. Su miktarının artışına bağlı olarak E1 ve E2 potansiyellerinde gözlenen bu kayma değerleri indirgenmiş Q•- ve Q2- türleri ile onların hidrojen bağlı formları arasında kurulan dengenin bir sonucudur. Bu çalışmalarda ortamdaki su miktarının artışına bağlı olarak potansiyel kayma değerleri ΔE/V (EFc-E2) okunarak kalibrasyon grafikleri oluşturulmuştur. 
Tez çalışmasının üçüncü basamağında, iyonofor özelliğe sahip taç eter grupları içeren ferrosenil naftakinon bileşiklerinin seçici katyon (alkali, toprak alkali katyonları) bağlama özellikleri ayrıntılı olarak incelenmiştir. Çalışmanın bu aşamasında (4b) bileşiği ile metal katyonları arasındaki kompleksleşme ilişkisi UV-VİS Spektrofotometrik ve kondüktometrik yöntemlerle gerçekleştirildi. Bu çalışmalarda, (4b) bileşiğinin alkali (Li+, Na+, K+, Cs+) ve toprak alkali (Be2+, Mg2+, Ca2+, Ba2+) iyonları ile kompleksleşmeleri ayrıntılı olarak incelendi. Bu çalışmalar ışığında (4b) bileşiğinin Ba2+ ve Ca2+ iyonlarını seçici olarak bağladığı tespit edildi. 

Anahtar Kelimeler: Elektrokimya, Ferrosen, Katyon-Bağlama, naftakinon, Su Tayini, Spektroelektrokimya, Taç-Eter.

Abstract:
This thesis consists of three main parts which are (1) synthesis of new and original multi-functional ferrocenyl naphthaquinones fused crown ethers, (2) devolepment of new voltammetric method based on the substituted ferrocenyl naphthaquinones to determine trace water in solvents, (3) investigation of selective cation-binding properties of ferrocenyl naphthaquinones substituted crown ether units. 
Novel ferrocenyl naphtaquinones fused crown ethers (benzo-15-crown-5 and benzo-18-crown-6) (4a, 4b) were synthesized by the reaction of ferrocenyl cyclobutenedione and lithio benzo-crown ethers. The lithio benzo-crown ethers were synthesized at low temperature (-78 °C) and under nitrogen atmosphere and transferred by means of a canula into ferrocenyl cyclobutenedione in a different reaction vessel at low temperature (-78 °C) and under nitrogen atmosphere. Ferrocenyl naphthaquinones will be achieved without isolation and purification of 4-hdroxy-2-cyclobutenone derivatives which are dissolved in p-xylene as crude product and heated at refluxed open to air to promote oxidation of intermediate hydroquinones. By this way, ferrocenyl naphthaquinones will be accomplished in a shorter time and consumed less chemicals such as solvents and silica gel. Designing of ferrocenyl naphthaquinones substituted crown ether units will be expanded by the reaction of ferrocenyl cyclobutenedione (1) and lithio dibenzo-crown ether. New compounds were characterized by FT-IR, 1H-NMR, 13C-NMR, mass spectroscopy, and elemental analysis methods. 
At the second stage of the thesis, the study of development of new voltammetric and electro-spectrophotometric methods based on the substituted ferrocenyl naphthaquinones performed by cyclic voltammetry and square-wave voltammetry techniques. In situ spectroelectrochemical measuerments will be carried out by a combination of couloamporemetric and spectrophotometric techniques in which time-resolved UV-vis spectral changes be observed depending on applied potentials. A three electrode system solid cell stand will be used for voltammetric measurements in some electrochemical solvents (DMSO (dimethyl sulfoxide), DMF (dimethyl formamide), CH3CN (acetonitrile), CH2Cl2 (dichloromethane), PhCN (benzonitrile), THF (tetrahydrofuran) ve propylen carbonate) which will be ultra-dried prior to each experiment. In aprotic organic solvents containing no added acid, the quinone undergoes one-electron reduction to the monoanionic radical (Q•−), which can be further reduced by one electron at more negative potentials to form the dianion (Q2−). The voltammetry has been shown to be heavily influenced by water in the solvent as the potential of both the first reduction process (E1/V) and especially the second reduction process (E2/V) shift to more positive potentials with increasing water concentration (ΔE2 > ΔE1). Eventually at high water concentrations the second process merges with the first process, corresponding to the reversible transfer of two electrons per molecule. It has been proposed that the shift in E1 and E2 with increasing water is due to an equilibrium that exists between the anionic quinones (Q•− and Q2−) and their hydrogen-bonded forms, which will be principle for development of new voltammetric and electro-spectrophotometric methods based on the substituted ferrocenyl naphthaquinones in this project. New electro-spectrophotometric methods based on the substituted ferrocenyl naphthaquinones will be devoleped by monitoring of spectral changes of Q•−product, obtained in a thin layer cell under applied potential, by addition of particular amount of water on it. Development of new voltammetric and electro-spectrophotometric methods based on the substituted ferrocenyl naphthaquinones will applied to determine water content in some petroleum and drug products as well as determine trace water in solvents. The selective cation-binding properties of ferrocenyl naphthaquinones substituted crown ether units measured by spectrophotometric titration technique will be performed by two different studies, one of which will be monitored spectral changes of the charge-transfer transitions of neutral ligands depending on metal-ligand interactions, the other be investigated spectral changes of monoanionic product (Q•−), formed in thin-layer cell under applied potentials, depending on metal-reduced ligand interactions. The properties of complex stability constant and selective cation-binding of ligands will be determined from the changing of the ratio of absorptions against metal concentration. In brief, our aim in this project is (1) to synthesis of new and original multi-functional ferrocenyl naphthaquinones and their complexes carrying ferrocene, quinone and crown ether groups on one molecular structure which gives rise to many analytical and technologic applications, (2) to develop new voltammetric and electro-spectrophotometric methods based on the substituted ferrocenyl naphthaquinones to determine trace water in solvents and some products, which has some superiority in the way of its more practical application over Karl Fischer titration technique and the methods in literature having some handicaps, (3) to investigate selective cation-binding properties (alkaline and earth-alkaline metals) of ferrocenyl naphthaquinones substituted crown ether units exhibiting ionophoric property.
Several recent studies show that the course of electroreduction for quinones is remarkably complex in the acidic medium. We have also presented an electrochemical approach to understand electron and proton-coupled electron transfer of the ferrocenyl naphthaquinones in nonaqueous solutions in the presence of weak and strong organic acids such as acetic acid (AcOH) and trifluoroacetic acid (TFA), thereby possibly evaluating the molecule Fc–cnq as a pH sensor.
At the third stage of the thesis, we comprehensively investigated selective cation binding properties of the ferrocenyl naphtaquinones fused crown ethers (4a, 4b) having ionophore character. The properties of complex stability constant and selective cation-binding of ligands were determined from the changing of the ratio of absorptions against metal concentration. The complexation between the ferrocenyl naphtaquinones benzo-18-crown-6 (4b) and metal cations was carried out by spectrophotometric and conductometric (4b) methods. We herein studied cation binding studies between the (4b) ligand and alkali (Li+, Na+, K+, Cs+) and earth-alkaline (Be2+, Mg2+, Ca2+ and Ba2+) metal ions. It was clearly seen that (4b) ligand showed selective Ba2+ and Ca2+ cation binding in the presence of the reported metal ions. 

Keywords: Cation-binding, Crown-ether, Electrochemistry, Ferrocene, Naphthaquinone, Spectroelectrochemistry, Water Determination.