Ayşe Gül Gürek

Octakis(alkylthio)-substituted phthalocyanines and their interactions with silver(I) and palladium(II) ions

Metal-free phthalocyanines and metal phthalocyaninates (M = Ni, Cu, Co or Zn) carrying eight alkylthio-groups on peripheral positions have been synthesised from 4,5-bis(alkylthio)phthalonitrile and 1,8-diazabicyclo[5.4.0]undec-7-ene (dbu) or the corresponding anhydrous metal salt [NiCl2, CuCl, CoCl2 or Zn(O2CMe)2]. The resulting compounds reacted with silver(I) or palladium(II) salts to form complexes with a phthalocyanine:metal ratio of 1 : 4. Spectrophotochemical investigation of these reactions revealed that complexation with AgI results in aggregation, while the addition of PdII destroys the aggregation and yields a new Q band at 720 nm.

Tetrathia macrocycle‐bridged dimeric with hexakis (alkylthio) substituents and network polymer phthalocyanines

1,7-dithia (12-crown-4)-bridged phthalocyanine network polymers were prepared from tetracyanodibenzo-[1,7-dithia(12-crown-4)]. In addition, the synthesis of two 1,7-dithia (12-crown-4) linked peripherally octa-substituted dimeric phthalocyanines, which contain a combination of hexakis(alkylthia) side chains, is described. These extremely soluble compounds were prepared by the condensation of an iminoisoindoline derivative and a subphthalocyanine. The novel compounds are characterized by elemental analyses, UV/vis, IR, mass, 1H NMR and 13C NMR spectroscopy. The electrical conductivity measurements of three of the four network polymers were unsuccessful; however chemical doping with NOBF4 could be increased to a measurable value. The electrical conductivity of the dimeric phthalocyanines are in the semiconductor range.

Mesomorphic phthalocyanine as chemically sensitive coatings for chemical sensors

Abstract Octa(13,17-dioxanonacosane-15-sulfanyl)-substituted mesomorphic nickel(II) phthalocyanine (Pc) at room temperature is investigated for the detection of organic solvent vapors by utilizing quartz crystal microbalance (QCM). Determined by polarized Raman spectroscopy, the Ni(II) Pc layers as coated were disordered and the Ni(II) Pc layers thermally treated were ordered. The ordered films on QCM-devices show higher sensitivity and partition coefficient for all solvent molecules investigated such as ethanol, dichloromethane, acetone, n -hexane. The Raman Spectroscopy investigation results show that the molecules with saturated CC bonds such as ethanol interact with phthalocyanine films predominantly by formation of hydrogen bonds and the sensor response to π bond containing compounds such as acetone is the result of their π–π interaction with conjugated phthalocyanine ring.

Electrochemical and spectroscopic investigation of neutral, oxidized and reduced double-decker lutetium(III) phthalocyanines

The double-decker lutetium(III) phthalocyanine [(C6H13S)8Pc]2Lu was investigated by electrochemical and spectroelectrochemical methods and comparisons made to previously investigated [(C12H25S)4Pc]2Lu and (Pc)2Lu under the some experimental conditions. All three compounds undergo a single reversible one-electron oxidation and up to four reversible one-electron reductions in CH2Cl2 containing 0.1 M tetra-n-butylammonium perchlorate (TBAP). The octa- and tetra substituted phthalocyanine derivatives exhibit one oxidation and three or four reductions in solution while five reductions can be detected for the two compounds in a gel-like cast film membrane of tetraoctylphosphonium bromide (4C8P+Br−) at a basal plane pyrolytic graphite electrode which was immersed in aqueous 0.5 M KCl. The half-wave potentials of these SR substituted complexes in CH2Cl2 are negatively shifted by 210-490 mV from E1/2 values for the same compounds in the aqueous 4C8P+Br− matrix and five reductions of these compounds are observed un...

ABAB homoleptic bis(phthalocyaninato)lutetium(III) complex: toward the real octupolar cube and giant quadratic hyperpolarizability.

The concept of octupolar molecules has considerably enlarged the engineering of second-order nonlinear optical materials by giving access to 2D and 3D architectures. However, if the archetype of octupolar symmetry is a cube with alternating donor and acceptor groups at the corners, no translation of this ideal structure into a real molecule has been realized to date. This may be achieved by designing a bis(phthalocyaninato)lutetium(III) double-decker complex with a crosswise ABAB phthalocyanine bearing alternating electron-donor and electron-acceptor groups. In this communication, we present the first step toward this goal with the synthesis, crystal structure determination, and measurement of the molecular first-order hyperpolarizability β by harmonic light diffusion, of an original lutetium(III) sandwich complex displaying the required ABAB-type alternation for one face of the cube. This structure is characterized by an intense absorption in the near-IR due to an intervalence transition and exhibits the highest quadratic hyperpolarizability ever reported for an octupolar molecule, √ = 5750 × 10(-30) esu.

Electrochemical and spectral properties of octakis(hexylthio)-substituted phthalocyanines

Abstract The redox properties of octakis(hexylthio)-substituted phthalocyanines with 2H, ZnII and CuII in the phthalocyanine core have been investigated by cyclic voltammetry in dichloromethane and the energies of photo-excitation and oxido-reduction processes have been compared. Two successive one-electron reduction and one-electron oxidation processes were observed for the complexes used in this work. The displacement of two protons in the inner core with metal ion was found to shift the first reduction potential of phthalocyanine ring to more negative values as a result of the π-back donation of the filld dπ of metal ion into the empty pc-π ∗ orbitals. The evaluation of cyclic voltammetry data together with the absorption spectra showed that photoexciatation arises from the orbitals below the HOMO for all the complexes used in this work.

Synthesis and Characterization of Octakis (hydroxyethylthio)-substituted Phthalocyanines

The new metal-free phthalocyanine 2 and phthalocyaninatometals 3–5 (M = Ni, Co and Zn) carrying eight hydroxyethylmercapto groups on peripheral positions have been synthesized from 1,2-bis(hydroxyethylmercapto)-4,5-dicyanobenzene in the presence of a suitable anhydrous metal salt [NiCl2, CoCl2 or Zn(O2CMe)2] or hydroquinone. Zinc (II) phthalocyaninate reacted with palladium(II) salt to form complexes with a phthalocyanine (metal ratio of 1:4). The electrical conductivity of the phthalocyanines 2, 3, 5, 5a are in the semiconductor range.

Synthesis and characterization of a new copper(II) phthalocyaninate substituted with four 15-membered tetraazamacrocycles and its water-soluble pentanuclear complexes

The synthesis of a new copper(II) phthalocyaninate substituted with four 15-membered tetraazamacrocycles from 15,16-dibromo-2,5,9,12-tetra(toluene-p-sulphonyl)-2,3,4,5,6,7,8,9,10,11,12,13-dodecahydro-1H-2,5,9,12-benzotetraazacyclopentadecine is described. Quaternization of the aza groups leads to water-soluble products. The tetraaza macrocyclic substituents bind transition-metal ions (CoII, NiII, CuII and ZnII) to give pentanuclear complexes whose electronic spectra indicate the presence of monomeric units in solution. The thermal stabilities of the compounds were determined by thermogravimetric analysis.

Synthesis and Liquid-crystalline Behaviour of Tetrakis- and Octakis(13, 17-dioxa nonacosane-15-sulfanyl)Phthalocyanines

Abstract Tetra- and octa(13, 17-dioxa nonacosane-15-sulfanyl) substituted metal free- and Ni(II) phthalocyanines have been synthesized from the corresponding phthalonitrile derivatives in the presence the anhydrous metal salt(NiCl2) or a strong organic base. The new compounds have been characterised by elemental analyses, IR, NMR and electronic spectroscopy and mass spectra. The mesogenic properties of these new materials were studied by differential scanning calorimetry(DSC), optical microscopy and X-ray investigations. All compounds show a discotic mesophase in an extremely large temperature interval including room temperature. X-ray diffraction patterns of the mesophases confirm that tetra-substituted compounds(5a, 5b) form a hexagonal ordered columnar mesophases(Dho), whereas octa-substituted compounds(7a, 7b) lead to centered rectangular disordered columnar mesophases(Drd).

Synthesis, photophysical and photochemical properties of poly(oxyethylene)-substituted zinc phthalocyanines

The synthesis, photophysical and photochemical properties of the tetra- and octa-poly(oxyethylene)substituted zinc (II) phthalocyanines are reported for the first time. The new compounds have been characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy, electronic spectroscopy and mass spectra. General trends are described for photodegradation, singlet oxygen, triplet state and fluorescence quantum yields, and triplet and fluorescence lifetimes of these compounds in dimethylsulfoxide (DMSO). Photophysical and photochemical properties of phthalocyanine complexes are very useful for PDT applications. The effects of the substituents on the photophysical and photochemical parameters of the zinc(II) phthalocyanines (3a, 5a and 6a) are also reported. The singlet oxygen quantum yields (Phi(Delta)), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism) ranged from 0.60 to 0.72. Thus, these complexes show potential as Type II photosensitizers. The fluorescence of the complexes was quenched by benzoquinone (BQ).