Yusuf Yerli

Design of a Gd-DOTA-Phthalocyanine Conjugate Combining MRI Contrast Imaging and Photosensitization Properties as a Potential Molecular Theranostic

The design and synthesis of a phthalocyanine – Gd‐DOTA conjugate is presented to open the way to novel molecular theranostics, combining the properties of MRI contrast imaging with photodynamic therapy. The rational design of the conjugate integrates isomeric purity of the phthalocyanine core substitution, suitable biocompatibility with the use of polyoxo water‐solubilizing substituents, and a convergent synthetic strategy ended by the use of click chemistry to graft the Gd‐DOTA moiety to the phthalocyanine. Photophysical and photochemical properties, contrast imaging experiments and preliminary in vitro investigations proved that such a combination is relevant and lead to a new type of potential theranostic agent.

Carbon Nanoparticles in Nematic Liquid Crystals

Fullerene C60, C70, single-walled and multi-walled carbon nanotubes and graphene sheets are doped to nematic liquid crystal (LC) host in the same percentage. Planar samples of these mixtures are prepared and our measurements constitute an optimization basis for possible applications. Fullerene balls are found to be the best compatible material for optical aims and reorientation of LC molecules, while the carbon nanotubes experience some reorientation possibility in LC media and graphene layers are good barriers to preserve reorientation.

Cyano-complexes and salts with tetracyanonickellateII and N,N-bis(2-hydroxyethyl)-ethylenediamine: synthesis, IR spectra, magnetic properties, thermal analyses, and crystal structures

Four cyano complexes, [Ni(N-bishydeten)Ni(CN)4] n (c1), [Cu(N-bishydeten)2][Ni(CN)4] (c2), [Zn2(N-bishydeten)2Ni(CN)4] n (c3), and [Cd(N-bishydeten)2][Ni(CN)4] (c4), have been synthesized and characterized by FT-IR, elemental, and thermal analyses. The structures of c2 and c4 were determined by single-crystal X-ray diffraction studies; both structures contain isolated cations and anions. The c2 consists of [Cu(N-bishydeten)2]2+ with octahedrally coordinated CuII and diamagnetic [Ni(CN)4]2–, but c4 consists of [Cd(N-bishydeten)2]2+, in which CdII is eight coordinate with two tetradentate N-bishydeten and diamagnetic [Ni(CN)4]2–. The value of the shape measure S (o) indicates that the coordination geometry around CdII lies along D 2d [dodecahedron; (dd)], C 2v [bicapped trigonal prism; (btp)], and D 4d [square antiprism; (sap)] but close to D 2d and D 4d. Variable temperature magnetic susceptibility measurements of c1 and c2 show the presence of little antiferromagnetic interaction below 20 K. Thermal analyses reveal that first neutral N-bishydeten and then cyano ligands were liberated from the complexes.

Synthesis and characterization of new heterometallic cyanido complexes based on [Co(CN)6]3− building blocks: crystal structure of [Cu2(N-bishydeten)2Co(CN)6]·3H2O having a strong antiferromagnetic exchange

A tetradentate N- and O- donor, N,N-bis(2-hydroxyethyl)-ethylenediamine, (N-bishydeten), has been employed to synthesize four new heterometallic cyanido complexes, [Ni2(N-bishydeten)2Co(CN)6]·3H2O (C1), [Cu2(N-bishydeten)2Co(CN)6]·3H2O (C2), [Zn2(N-bishydeten)2Co(CN)6]·5H2O (C3) and K[Cd(N-bishydeten)Co(CN)6]·1.5H2O (C4). Characterization of the complexes was performed using IR and EPR spectroscopy (for C2), thermal analysis and elemental analysis techniques. The crystal structure of C2 was determined by the X-ray single crystal diffraction technique. The asymmetric unit of C2 consists of cyanido-bridged trinuclear Cu1Cu2Co3 units {-CN-Cu1(N-bishydeten)-μ-O-Cu2(N-bishydeten)-NC-Co3(CN)4-CN-} and three water molecules. The water molecules are situated in the inter-fragment spaces. The [Cu2(N-bishydeten)2]2+ cations are linked to the [Co(CN)6]3− anions via two cyanido bridges to give a 1D neutral zigzag chain. One of two N-bishydeten cations bridges five coordinated Cu1 and six coordinated Cu2 through deprotonated η1-O2 and the charge of C2 is counterbalanced by this η1-O2. The IR spectrum of C2 is quite different from other complexes, three ν(CN) absorption bands were observed due to different cyanido groups in its structure. The thermal decomposition of C1–C4 is processed in multistages. Variable temperature magnetic susceptibility measurement recorded in the 10–300 K range showed the presence of a strong antiferromagnetic exchange interaction in C2 between Cu1 and Cu2 by η1-O2.

Development of Halbach magnet for portable NMR device

Nuclear magnetic resonance (NMR) has enormous potential for various applications in industry as the on-line or at-line test/control device of process environments. Advantage of NMR is its non-destructive nature, because it does not require the measurement probe to have a contact with the tested media. Despite of the recent progress in this direction, application of NMR in industry is still very limited. This is related to the technical and analytical complications of NMR as a method, and high cost of NMR analyzers available at the market. However in many applications, NMR is a very useful technique to test various products and to monitor quantitatively industrial processes. Fortunately usually there is no need in a high-field superconducting magnets to obtain the high-resolution spectra with the detailed information on chemical shifts and coupling-constant. NMR analyzers are designed to obtain the relaxation parameters by measuring the NMR spectra in the time domain rather than in frequency domain. Therefore it is possible to use small magnetic field (and low frequency of 2-60 MHz) in NMR systems, based on permanent magnet technology, which are specially designed for specific at-line and on-line process applications. In this work we present the permanent magnet system developed to use in the portative NMR devices. We discuss the experimental parameters of the designed Halbach magnet system and compare them with results of theoretical modelling.

TiO-Based Organic Hybrid Solar Cells with Mn

A hybrid solar cell is designed and proposed as a feasible and reasonable alternative, according to acquired efficiency with the employment of TiO2 (titanium dioxide) and Mn-doped TiO2 thin films. In the scope of this work, TiO2 (titanium dioxide) and Mn:TiO2 hybrid organic thin films are proposed as charge transporter layer in polymer solar cells. Poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT: PCBM) is used as active layer. When the Mn-doped TiO2 solar cells were compared with pure TiO2 cells, Mn-doped samples revealed a noteworthy efficiency enhancement with respect to undoped-TiO2-based cells. The highest conversion efficiency was obtained to be 2.44% at the ratio of 3.5% (wt/wt) Mn doping.

Nitronyl and imino nitroxide free radicals as precursors of magnetic phthalocyanine and porphyrin building blocks

Phthalonitrile and benzaldehyde bearing α-nitronyl and α-imino nitroxide free radicals have been synthesized as precursors of nitroxide substituted phthalocyanine and porphyrin macrocycles. To ascertain the structure and radical type they have been characterized by single crystal X-ray crystallography and by electron paramagnetic resonance spectroscopy (EPR). Their EPR spectra coincide with those reported for previous nitroxides and are in good agreement with literature. Electrospray ionization mass spectroscopy (ESI) was used as a complementary and an alternative technique. Depending on the nature of the radical, two ionization behaviors have been underscored; imino radicals were detected as the [MH2]+ cation ions and nitroxide radicals were detected as the [MH]+˙ radical cations. This differentiation is pointed out as an efficient and rapid method for preliminary characterization of the radical moieties and a judicious technique that allows the prompt detection of radicals at low concentration and straightforward confirmation of the structure.

Crystal structure and EPR studies of doped Cu2+ ion in [Zn(sac)2(en)2] single crystal

The tran-bis(ethylenediamine)bis(saccharinato)Zinc(II), [Zn(sac)(2)(en)(2)] (ZSED), (en: ethylenediamine and sac: saccharinate) complex has been synthesized and its crystal structure has been determined by X-ray diffraction analysis. The compound crystallizes in space group P2(1)/c. The Zn(II) ion is hexa-coordinated by four nitrogens of two bidentate en ligands composing the basal plane and two nitrogen atoms from the monodentate two sac ligands (N-bonded) occuping the axial sites, adopting an elongated octahedral sphere. Both en and sac ligands occupy the trans positions of the coordination octahedron. The Zn(II) ion in title compound sits on a inversion centre and is octahedrally coordinated two bidentate en (ethylenediamine) and two sac (saccharinate) (N-bonded) ligands. The magnetic environments of Cu(2+) doped [Zn(sac)(2)(en)(2)] complex have been identified by electron paramagnetic resonance (EPR) technique. Cu(2+) doped ZSED single crystals have been studied at room temperature in three mutually perpendicular planes. The calculated results of the Cu(2+) doped ZSED indicate that Cu(2+) ion contains two magnetically inequivalent Cu(2+) sites in distinct orientations occupying substitutional positions in the host lattice and show very high angular dependence.

Effect of substituents on spin density in benzimidazole nitronyl nitroxide radicals studied by electron spin resonance

Several novel benzimidazole‐3‐oxide‐1‐oxyl radicals with substituents at 5 and/or 6 position were synthesized. The ESR analysis of nitrogen hyperfine coupling constants (hfccs) revealed that substituents at 5 and 6‐position affect the spin density to greater extent than substituents on the phenyl ring at 2‐position. Density functional theory calculations of nitrogen hfccs were performed using several different Pople type basis sets, as well as double and triple zeta quality individual gauge for localized orbital (IGLO‐II, IGLO‐III) and electron paramagnetic resonance (EPR‐II, EPR‐II) basis sets. Experimental and theoretical hfccs are compared. Copyright

Synthesis and EPR studies of soluble vanadyl octakis(4-tert-butylbenzylthio) porphyrazine

Magnesium porphyrazinate substituted with eight 4-tert-butylphenylthio-groups on peripheral positions has been synthesized by cyclotetramerization of 1,2-bis(4-t-butylphenylthio)maleonitrile in the presence of magnesium butanolate. The metal-free derivative was obtained by treatment with trifluoroacetic acid and further reaction of this product with vanadyl(IV) sulfate led to the vanadyl porphyrazinate. These new compounds have been characterized by elemental analysis, together with FTIR, and UV–vis spectral data. The magnetic properties of the complex have been investigated by electron paramagnetic resonance spectroscopy.