Synthesis and electrochemical,electrical and gas sensing properties of novel mononuclear metal-free,Zn(II), Ni(II), Co(II), Cu(II), Lu(III) and double-decker Lu(III) phthalocyanines substituted with 2-(2H-1,2,3-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl) phenoxy

A new mono substituted phthalonitrile derivative 3 was prepared by a nucleophilic displacement reaction of 4-nitrophthalonitrile with 2-(2H-1,2,3-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol. Novel metallophthalocyanines 4–8 (M = Zn, Ni, Co, Cu, Lu, respectively), metal free 9 and double decker Lu(III) phthalocyanine 10 with four peripheral 2-(2H-1,2,3-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenoxy groups were synthesized by cyclotetramerisation of the phthalonitrile and characterized by elemental analyses, FTIR, ¹H NMR, UV–vis and MALDI-TOF MS spectral data. Cyclic voltammetry, differential pulse voltammetry and in situ spectroelectrochemistry of the phthalocyanine compounds have been studied. This allowed us to identify and compare metal- and phthalocyanine ring-based redox processes of the complexes. Impedance spectroscopy (IS) and dc conductivity measurements were performed as a function of temperature (300–430 K) and frequency (40–10⁵ Hz.). The sensing properties of the films for toluene were also investigated. The dc results showed an activated conductivity dependence on temperature for all films. While room temperature impedance spectra consist of a curved line, a transformation into a full semicircle with increasing temperature was observed. The analysis of ac conductivity data showed that the CBH model is the dominant conduction mechanism for the electron transport in the films. While exposure to toluene has no effect on the conductivity of the film of 8–10 completely reversible sensor response to toluene only were obtained for compounds 4–7. It was also observed that the operating temperature had a considerable effect on sensing characteristics of the films.     

Synthesis,electrochemistry, spectroelectrochemistry and electrocolorimetry of phthalocyanine–anthraquinone hybrids

The tetra substituted metallophthalocyanines 2 and 3, soluble in common organic solvents, bearing four 2-(9,10-dioxo-9,10-dihydro-anthracen-2-yl-methyl)-malonic acid diethyl ester functionalities were synthesized from the corresponding phthalodinitrile 1 and divalent metal salts at 170 °C in fused state. Reaction of with manganese (2+) acetate in n-pentanol led to the manganese (3+) phthalocyanine 4. Furthermore, the unsymmetrical copper phthalocyanine 5 containing one 2-(9,10-dioxo-9,10-dihydro-anthracen-2-yl-methyl)-malonic acid diethyl ester moiety was synthesized using a statistical approach. The new compounds were characterized by elemental analysis together with FT-IR, ¹H-NMR, ¹³C-NMR, and UV–vis spectroscopy and via mass spectrometric analysis. The electrochemical, in situ spectroelectrochemical, and in situ electrocolorimetric measurements represent that while MPcs give common ring-based and/or metal-based electron transfer processes, these processes were considerably affected with the redox processes of the AQ units attached to the phthalocyanine ring. At the same time attachments of the AQ units to the phthalocyanine rings improve the reversibility of the AQ units due to the electron donor–acceptor interaction between the AQ units and phthalocyanine ring. The AQ units also alter the color states of the phthalocyanines.     

Synthesis,electrochemical and spectroelectrochemical properties of highly soluble tetra substituted phthalocyanines with [4-(thiophen-3-yl)-phenoxy]

Zinc, oxo-titanium, cobalt, and manganese phthalocyanine derivatives substituted with nonperipheral 3-(tetra[4-(thiophen-3-yl)-phenoxy] moieties have been synthesized and characterized by elemental analysis, IR, ¹H NMR spectroscopy, electronic spectroscopy, and mass spectra. The compounds have good solubility in various polar and nonpolar organic solvents and not aggregated (in the same solvents) within a wide concentration range. Electrochemical and spectroelectrochemical measurements exhibit that incorporation redox active metal centers, Co^II, Ti^IVO and Mn^IIIOAc into the phthalocyanine core extend the redox richness of the Pc ring with the reversible metal-based reduction and oxidation couples of the metal centers in addition to the common Pc ring-based electron transfer processes.     

Polymerization of thiophene containing cyclobutadiene Co cyclopentadiene complexes

To understand the charge transport ability of the metal coordinated cyclobutadiene, a series of cyclobutadiene cobalt cyclopentadiene (CbCoCp) complexes containing electrochemically polymerizable thiophene units were synthesized. The complexes were electrochemically polymerized and the resulting polymers were characterized by cyclic voltammetry, in situ conductivity and UV–vis spectroelectrochemistry. Several different derivatives of the CbCoCp complexes and a model study suggested that if the oxidation of the organic fragment was above Co^I/II redox couple of the CbCoCp complex, detrimental side reactions occured. Side reactions did not occurred if the oxidation of the organic fragment was below the metal oxidation.     

Preparation,characterization, electrochemistry and in situ spectroelectrochemistry of novel α-tetra[7-oxo-3-(2-chloro-4-fluorophenyl)coumarin]-substituted metal-free,cobalt and zinc phthalocyanines

In this study, a novel ligand, 7-(2,3-dicyanophenoxy)-3-(2-chloro-4-fluorophenyl)coumarin was synthesized by the reaction of 3-(2-chloro-4-fluorophenyl)-7-hydroxycoumarin with 1,2-dicyano-3-nitrobenzen in dry DMF as the solvent in the presence of K₂CO₃ as the base. The preparation of the corresponding phthalocyanines H₂Pc, CoPc and ZnPc, substituted with 7-oxo-3-(2-chloro-4-fluorophenyl)coumarin functional groups at α positions of the Pc ring, was achieved by the cyclotetramerization of the coumarin ligand without any metal salts or with the relevant metal(II) acetates in 2-N,N-dimethylaminoethanol. The structures of the compounds were confirmed by elemental analysis, UV–vis, IR, MALDI-TOF mass and ¹H NMR spectra. In addition, aggregation and redox properties of the novel phthalocyanines with four halogenated coumarinoxy substituents at α positions of the phthalocyanine ring were compared with those of previously reported corresponding ones with β-substitution, by UV–vis spectroscopy, in situ spectroelectrochemistry and voltammetry. Remarkable differences in these properties between α- and β-substituted compounds were detected, and discussed in detail.     

Metal ion sensing functional mono and double-decker lanthanide phthalocyanines: Synthesis,characterization and electrical properties

We report, in this study, the preparation, physical characterization metal ion sensing properties of peripherally functionalized ionophore ligand, 4,5-bis(6-hydroxyhexylthio)-1,2-dicyanobenzene (1) and its mono 2,3,7,8,12,13,17,18-octakis(6-hydroxyhexylthio)phthalocyaninatometal (II) {M = Zn^II (2), Cu^II (3)} and double-decker lanthanide bis-phthalocyanines, {([4,5,4′,5′ 4″,5″,4?,5?]-tetrakis-(6-hydroxyhexylthio)phthalocyaninatolanthanium(III)}){M[Pc(S–C₆H₁₃OH)₄]₂} {M = Eu^III (4), Yb^III (5), and Lu^III (6)}. All benzenes on phthalocyanines are functionalized with hydroxyhexylsulfanyl moieties for potential use as soft metal ion binding, such as Ag⁺ and Pd²⁺. The temperature dependence of the dc and ac conduction properties of 4, 5 and 6 thin films have been investigated in the frequency range of 40–10⁵ Hz and temperature range 290–436 K. The dc results showed an activated conductivity dependence on temperature for all films. Obtained data reveal that ac conductivity obeys the relation σ_ac(ω) = Aω^s and exponent is found to decrease by increasing temperature. The data obtained results were compared with the prediction of the Quantum Mechanical Tunelling (QMT) and Correlated Barrier Hopping (CBH) models. The analysis showed that the CBH model is the dominant conduction mechanism for the electron transport in the films. The new synthesized compounds have been characterized by elemental analysis, FTIR, ¹H and ¹³C NMR, MS, UV–vis and EPR spectral data.     

Synthesis,characterization, and electrical,electrochemical and gas sensing properties of a novel cyclic borazine derivative containing three phthalocyaninato zinc(II) macrocycles

A novel borazine derivative of trinuclear phthalocyanine has been prepared by following the multistep reactions of unsymmetrically substituted phthalocyanines. 4-(4-Amino-3-nitrophenoxy)phthalonitrile (3) which is one of the precursor molecules of the phthalocyanine was obtained from 4-nitrophthalonitrile (1) and 4-amino-3-nitrophenol (2) with K₂CO₃ in DMF at 50 °C. The zinc(II) phthalocyanine (5) containing an unsymmetrical substituted 4-amino-3-nitrophenoxy group was synthesized by statistical condensation of two different phthalonitriles. 4-(4-Amino-3-nitrophenoxy)phthalonitrile (3) and 4,5-bis(hexylthio)phthalonitrile (4) were cyclotetramerized with zinc acetate in DMF at 170–180 °C to yield 2-(4-amino-3-nitrophenoxy)-9,10,16,17,23,24-hexa(hexylthio)phthalocyanine zinc(II) complex (5), which was then separated by column chromatography on silica gel. The unsymmetrically substituted compound was reduced to the diamine form (6) using hydrazine hydrate in the presence of Pd/C catalyst, and the product was purified with chromatographic separation. Compound 6 was then reacted with triisopropoxyborane in refluxing xylene to give 5H,12H,19H-tris[2-(3,4-diaminophenoxy)-9,10,16,17,23,24-hexa(hexylthio)phthalocyaninato zinc(II) diazaborolo] borazine (7). The resulting product was purified by column chromatography on silica gel. All the target unsymmetrical phthalocyanines and borazine derivative were characterized by elemental analysis, IR, UV–vis, and ¹H NMR. Boron and zinc(II) percents in 7 were quantified with ICP-MS. Impedance spectroscopy and dc measurements were performed on spin coated 5–7 films as a function of temperature (293–400 K). The dc results showed an activated conductivity dependence on temperature. The ac results gave a temperature dependent frequency exponent s. The results were compared with the prediction of the Quantum Mechanical Tunelling and Correlated Barrier Hopping models. The ac conductivity of the films was well represented by the form Aω^s. Gas sensing properties of the films for the volatile organic compounds (VOCs) (chloroform, acetone, carbontetrachloride and ammonia) were also investigated in the temperature range from 293 to 400 K. The operating temperature had a considerable effect on sensing characteristics. Maximum sensitivity to VOCs were observed at room temperature for all films. Cyclic voltammetry of compounds 6 and 7 in solution indicated that these compounds have similar voltammetric behaviour.     

Synthesis and electrochemical properties of novel oligo-TTF donors

A series of novel oligomeric electron donors containing two to six TTF cores (5–11) were synthesized. The structures were assigned by NMR spectroscopy, infrared spectrometry and mass spectra. Their electrochemical properties were investigated by cyclic voltammetry (CV). All the compounds exhibited two pairs of nearly ideal redox waves. No distinct shift of the redox potentials was observed when TTF units increased.     

Two dication salts of ET: preparation and crystal structures of ET [FeII(CN)4(CO)2]

Single crystals of new dication bis(ethylenedithio)tetrathiafulvalene salts with [Fe^II(CN)₄(CO)₂]²⁻ were prepared electrochemically. Two kind crystals (A and B) with the same composition and different stacking patterns were derived from Na₂[Fe^II(CN)₄(CO)₂] and TBA₂[Fe^II(CN)₄(CO)₂], respectively.     

Synthesis,characterization and electrical and CO2 sensing properties of triazine containing three dendritic phthalocyanine

The metal-free phthalocyanine 1a was synthesised by statistically mixed condensation of 4-nitrophthalonitrile and 4-(2-dimethylaminoethylsulfanyl)phthalonitrile in dry 2-(dimethylamino)ethanol. The same route were applied to prepare metal-containing phthalocyanines using metal salts Zn(OAc)₃·2H₂O and CoCl₂, respectively, in dry DMF. The nitro compounds were reduced to amine with sodium sulfide and quarternized by reaction of MeI. These compounds were then reacted with cyanuric chloride in the presence of potassium carbonate as a base in mixture of THF and DMF gave s-triazine containing three amino phthalocyanines 4a–c. The reaction of three phthalocyanines with sodium salt of triethylmethanetricarboxylate in absolute ethanol were synthesised first generation of dendrimer 5a–c. The second generation of dendritic phthalocyanines 6a–c were prepared by the reaction of dentritic phthalocyanines with tris (H₂NC(CH₂OH)₃) using K₂CO₃ as a base in DMSO. The dendritic phthalocyanines containing tris are slightly soluble in water. The new compounds were characterized by elemental analysis and UV–vis, IR, NMR spectra. The temperature dependence of the dc and ac conductivity of these compounds and the adsorption of CO₂ gas on thin film of the compounds were investigated by dc conductivity and impedance spectroscopy technique using an interdigital transducer structure on glass substrate. While exposure to CO₂ have no influence on the electrical conductivity (ac and dc) of compound 6a and 6c, the conductivity of the film of 6b strongly depend on the presence of the CO₂ gas. Completely reversible sensor signals were obtained for compound 6b. The impedance spectra were obtained at frequencies between 40 and 10⁵ Hz, and in a wide range of CO₂ concentrations (from 500 to 8000 ppm) at room temperature. The temperature dependence of dc conductivity show typical Arrehenius behaviour for all compounds. The ac conductivity of the films is represented by the form ω^s. The dependency of frequency exponent s on temperature suggests a correlated barrier hopping (CBH).     

Novel `synthetic metals' based on symmetrically tetrasubstituted nickel phthalocyanines

Nickel(II) 2,9,16,23-tetrasubstituted phthalocyanines, NiPTX (where X=–OH, –NO₂, –NH₂ and –SO₃H) were synthesized in pure state and doped with iodine. Elemental analysis, UV-Vis, infrared, X-ray diffraction, magnetic susceptibility and TGA studies were used to investigate the effects of iodine doping as well as substituents on the properties of the complexes. The electrical conductivity of nickel phthalocyanine derivatives found to depend on the nature of the substituents and showed ∼10³–10⁵ times increased electrical conductivity in comparison to parent nickel phthalocyanine. Further, the substitution and iodine doping show remarkably very high improved electrical conductivity nearly 10¹¹ times the electrical conductivity of nickel phthalocyanine.     

Electrochemical synthesis and characterization of poly[3′-(4-formyl-3-hydroxyphenyl)-5,2′:5′,2″-terthiophene] film

A conducting polymer was electrochemically prepared on a Pt electrode with newly synthesized 3′-(4-formyl-3-hydroxyphenyl)-5,2′:5′,2″-terthiophene (FHPT) in a 0.1 M TBAP/CH₂Cl₂ solution. The poly[FHPT] film was characterized with cyclic voltammetry, in situ UV–vis spectroscopy, in situ conductivity measurements, and EQCM. From in situ UV–vis spectroscopy results, it was confirmed that generation of polaron and bipolaron was directly related to the conductivity of the poly[FHPT] film. The conductivity was 4.5 S/cm at +1.5 V. The poly[FHPT] film showed a specific catalytic response for the proton at the current media below pH 4. It also exhibited a specific catalytic response by metal ions.     

Synthesis,characterization, conductivity,band gap and thermal analysis of poly-2-[(4-mercaptophenyl) imino methyl] phenol and some of its polymer–metal complexes

The oxidative polycondensation reaction conditions of 2-[(4-mercaptophenyl) imino methyl] phenol (4-MPIMP) was studied in an aqueous alkaline medium between 30 and 90 °C by using oxidants such as air O₂, NaOCl and H₂O₂. Polymer–metal complex compounds were synthesized from the reactions of poly-2-[(4-mercaptophenyl) imino methyl] phenol (P-4-MPIMP) with Cr³⁺, Co²⁺, Ni²⁺, Cu²⁺, Mn²⁺, Zn²⁺, Pb²⁺, Cd²⁺ and Zr⁴⁺ ions. The structures of these monomer and polymer were identified from UV–vis, FT-IR, ¹H NMR, ¹³C NMR and elemental analysis. While thermal analysis of P-4-MPIMP and polymer–metal complexes were made by TGA–DTA, the number-average molecular weight (M_n), weight-average molecular weight (M_w) and polydispersity index (PDI) values of this polymer were determined by size exclusion chromatography (SEC). According to TG–DTA analyses, P-4-MPIMP–Cu was found to be higher stable than other synthesized polymer and polymer–metal complexes. While conductivity measurements of polymer and polymer–metal complexes were done by electrometer using four point probe techniques, electrochemical and optical band gap values of 4-MPIMP, P-4-MPIMP and polymer–metal complexes were determined by using cyclic voltammetry and UV–vis measurements. Conductivity and band gap values show that this polymer and polymer–metal complexes are a typical semiconductor.     

Preparation and characterization of a polypyrrole hybrid film with [Ni(dmit)2]2−, bis(1,3-dithiole-2-thione-4,5-dithiolate)nickellate(II)

The synthesis of a hybrid material obtained by electropolymerization of a solution of pyrrole and [NEt₄]₂[Ni(dmit)₂] (dmit = 1,3-dithiole-2-thione-4,5-dithiolato) in acetonitrile solution is reported. The material was characterized by cyclic voltammetry, UV–vis and infrared spectroscopies, scanning electron microscopy (SEM), atomic force microscopy (AFM) and thermal gravimetric analysis (TGA). The FTIR spectroscopy showed that the [Ni(dmit)₂]²⁻ anion has been inserted in the polypyrrole framework and was not destroyed or modified during the polymerization process. The voltammetric analysis indicated that the material has electroactivity and undergoes redox processes associated with the conducting polymer and the counteranion. The cyclic voltammetry results also suggest that the counteranion is not trapped in the PPy matrix undergoing anion exchange during the redox cycle of PPy. The PPy/[Ni(dmit)₂]²⁻ exhibits good thermal stability and a intrinsic conductivity value in the range of semiconductors (10⁻³ S cm⁻¹).     

Synthesis and redox behavior of benzo-1,3-dithiafulvalenes incorporating ferrocene moiety as redox active ligands

A simple route for the synthesis of several new benzo-1,3-dithiafulvalenes incorporated with ferrocene (Fc) moiety is reported. The benzo-1,3-dithiafulvalenes (6a–f) were synthesized by introducing a ferrocene coordination function as new donor compounds based on the Wittig–Horner olefenation method. The redox behavior of the new donor compounds was investigated in comparison with the ferrocene and established 1,4-dithiafulvalenes by cyclic voltammetry. Two couples of redox peaks were observed for both ferrocene and extended dithiafulvalene (DTF).     

Synthesis and electrochemical,electrochromic and electrical properties of novel s-triazine bridged trinuclear Zn(II), Cu(II) and Lu(III) and a tris double-decker Lu(III) phthalocyanines

The new s-triazine-bridged trinuclear Zn(II) and Cu(II) phthalocyanines have been synthesized from the reaction of corresponding anhydrous metal salts, Zn(OAc)₂ and CuCl with 4,5-bis(hexylthio)-phthalonitrile and 2,4,6-tris(2-thiophthalonitrile)-s-triazine. The tris phthalonitrile derivative of s-triazine was prepared from the reaction of 4-nitrophthalonitrile and thiocyanuric acid in dry dimethylformamide as solvent using K₂CO₃ as the base. The same route was applied to prepare the trinuclear Lu(III) phthalocyanine analogue. The conversion of tris phthalonitrile into its isoindoline derivative was accomplished by bubbling ammonia gas through a solution in methanol in the presence of sodium methoxide. The cyclization of two different isoindoline derivatives and 4,5-bis(hexylhthio)-1,2-diiminoisoindoline, with lutetium (III) acetate in dimethylformamide gave trinuclear Lu(III) phthalocyanine. The reaction of this complex with octakis-hexylthio phthalocyanine led to the isolation of tris double-decker Lu(III) phthalocyanine. The structures of the target compounds were confirmed by elemental analysis, UV–vis, IR and MALDI-TOF mass spectroscopies. The d.c. and a.c. conductivities of the phthalocyanine compounds were measured as a function of temperature. The small value of pre-exponential factor suggested the conduction by localized states in the band tails and by localized states near the Fermi level. The temperature dependence of the frequency exponent showed that the conduction in these compounds is due to hopping of charge carriers. The tris double-decker phthalocyanine complex showed well-defined electrochromic behaviour with green-blue and blue-purple colour transitions.     

Ferromagnetism and its photo-induced effect in 2D iron mixed-valence complex coupled with photochromic spiropyran

Iron mixed-valence complex, (n-C₃H₇)₄N[Fe^IIFe^III(dto)₃] (dto = C₂O₂S₂), shows a spin-entropy driven phase transition called charge transfer phase transition around 120 K and a ferromagnetic transition at 6.5 K. These phase transitions remarkably depend on the hexagonal ring size in two-dimensional honeycomb network structure of [Fe^IIFe^III(dto)₃]_∞. In order to control the magnetic properties and the electronic state in the dto-bridged iron mixed-valence system by means of photo-irradiation, we have synthesized a photo-sensitive organic–inorganic hybrid system, (SP)[Fe^IIFe^III(dto)₃] (SP = spiropyran), and investigated the photo-induced effect on the magnetic properties by the measurements of magnetic susceptibility, ESR, IR, UV–vis and ⁵⁷Fe Mössbauer spectra. Upon UV irradiation at 337 nm, a broad absorption band between 500 nm and 600 nm appears and continuously increases with the photo-irradiation time, which implies that the UV irradiation changes the structure of spiropyran from closed form to open one in solid state. The photochromism in spiropyran changes the ferromagnetic transition temperature and the coercive force.     

Preparation and ionophoric properties of coronene fluoroionophores containing azacrown and calix[4]azacrown ethers

Novel coronene fluoroionophores, N,N′-dipropyl-5,11-bis[4-(1-aza-18-crown-6)phenyl]cornene-2,3,8,9-tetracarboxy diimide (4), and N,N′-dipropyl-5,11-bis[4-(calix[4]azacrown-5-crown-5)phenyl]coronene-2,3,8,9-tetracarboxy diimide (6), were prepared by reacting N,N′-dipropyl-5,11-bis(p-chlorophenyl)coronene-2,3,8,9-tetracarboxy diimide (3) with 1-aza-18-crown-6 or calix[4] azacrown-5-crown-5. Alternating copolymers, 5 and 7, with a similar repeating unit were prepared by reacting 7,16-diaza-18-crown-6 or calix[4]bisazacrown-5 with compound 3. The fluoroionophoric characteristics were investigated by binding alkali, alkali earth metal and various metal ions. The model and polymeric fluoroionophores exhibited significant decreasing fluorescence effects with K⁺, Ag⁺ and Ba²⁺, which were attributed to photoinduced charge transfer (PCT).     

The first BDH-TTP radical cation salts with mercuric counterions, κ-(BDH-TTP)4[Hg(SCN)4]·C6H5NO2 and α′-(BDH-TTP)6[Hg(SCN)3][Hg(SCN)4]

Two new radical cation salts of the non-TTF containing donor BDH-TTP with the thiocyanatomercurate anions were synthesized. The κ-(BDH-TTP)₄[Hg(SCN)₄]·C₆H₅NO₂ (1) and α′-(BDH-TTP)₆[Hg(SCN)₃][Hg(SCN)₄] (2) salts were characterized by single crystal X-ray diffraction, electrical resistance measurements and electronic band structure calculations. Both salts have a layered structure in which the BDH-TTP layers of κ- or α′-type alternate with anionic sheets. The anionic layers of 1 contain the counterion [Hg(SCN)₄]²⁻ and the nitrobenzene molecule which are statistically disordered. Salt 2 contains two different layers (although both of the α′-type) of the organic donors, a somewhat unusual fact in organic conductors. The anion layers of 2 consist of polymeric chains built up from a combination of the two different anions, [Hg(SCN)₃]¹⁻ and [Hg(SCN)₄]²⁻. Salt 1 shows a metallic behavior down to helium temperatures whereas salt 2 exhibits two-phase transitions in the temperature range 295–8 K.