Ball-Type Phthalocyanines: Synthesis and Properties

A Single-Molecule Chemical Reaction Studied by High-Resolution Atomic Force Microscopy and Scanning Tunneling Microscopy Induced Light Emission

Atomic force microscopy (AFM) as well as scanning tunneling microscopy induced light emission (STM-LE) are, each on their own, powerful tools used to investigate a large variety of properties of single molecules adsorbed on a surface. However, accessing both structural information by AFM as well as optical information by STM-LE on the same molecule so far remains elusive. We present a combined high-resolution AFM and STM-LE study on single metal-oxide phthalocyanines. Using atomic manipulation, the molecules can be deliberately reduced. We demonstrate structure elucidation and adsorption geometry determination of single molecules with atomic resolution combined with optical characterization by STM-LE and the possibility of investigating the change in a molecule's exciton emission intensity by a chemical reaction.

Synthesis, characterization and OFET property of four diaminouracil bridged novel ball-type phthalocyanines

New ball-type metallobisphthalocyanines 2 (Co[Formula: see text]Pc[Formula: see text] and 3(Zn[Formula: see text]Pc[Formula: see text] were synthesized from the corresponding 4,4[Formula: see text]-[(5,6-diaminopyrimidine-2,4-diyl)bis(oxy)] diphytalonitril 1, which can be obtained by a nucleophilic displacement reaction of 4-nitrophthalonitrile with 5,6-diaminouracil sulfate. Characterization of novel compounds was performed by UV-vis, FT-IR, [Formula: see text]H-NMR, MALDI-TOF mass spectroscopy and elemental analysis. Organic field effect transistor devices (OFETs) with top gate structure were fabricated using these novel compounds as the active material. The devices were characterized by means of their output and transfer characteristics, and it was found that these OFET devices exhibit [Formula: see text]-type behavior. When compared with the 2-based device, the OFET with 3 showed higher field effect mobility and larger on/of current ratio.

Structural, spectroscopic and passivation properties of a novel binuclear clamshell-type zinc(II) phthalocyanine as gate dielectric for OFET

A novel clamshell-type binuclear zinc(II) phthalocyanine (2) was synthesized by cross condensation of the bisphthalonitrile (1) with 4-tert-butylphthalonitrile and zinc acetate in 1:10:4 ratio. The structure of the novel compound was characterized by elemental analysis, UV-vis, FT-IR (ATR), HR MALDI-TOF mass, [Formula: see text]H NMR, [Formula: see text]C DEPT NMR and [Formula: see text]H–[Formula: see text]H COSY NMR methods. Applying electronic absorption spectroscopy and density functional theory (DFT) revealed that in THF the geometry of 2 is twisted to adopt an intermediate clamshell conformation in which the spacing between the Zn centers is about 8.1Å, providing a very good account of the observed spectrum exhibiting the characteristic B (Soret) band at 347 nm and the Q band at 673 nm. In solution, 2 was found to exist in non-aggregated form. The calculated fluorescence quantum yields ([Formula: see text] 0.23 in THF and 0.10 in DMF) were relatively reduced in comparison to that of std ZnPc. In particular, understanding of leakage current conduction mechanisms in gate dielectrics is crucial for the development of field effect transistors with improved device performance. Analysis of the reverse bias current–voltage data indicated that the origin of leakage current conduction mechanisms in clamshell-type zinc(II) phthalocyanine is Poole-Frenkel emission. The capacitance density of 12.7 nF cm[Formula: see text] at 5 Hz. and 12.1 nF cm[Formula: see text] at 13 MHz was obtained with the FTO/Pc/Au sandwich structure.

Synthesis and photophysical and electrochemical properties of novel unsymmetrical phthalocyanines with a Sudan IV moiety

The synthesis of novel, A[Formula: see text]B type unsymmetrical metal-free and metallophthalocyanines bearing one aza dye group Sudan IV and three nitro terminal moieties was achieved by cyclotetramerization of novel 4-((1-((E)-(2-methyl-4-((E)-[Formula: see text]-tolyldiazenyl)phenyl)diazenyl)naphthalen-2-yl)oxy)phthalonitrile and 4-nitrophthalonitrile. The new unsymmetrical metal-free and metallophthalocyanines have been characterized using elemental analyses, [Formula: see text]H NMR, FT-IR, UV-vis and mass spectroscopic data. The aggregation properties of the compounds were investigated in a concentration range of 1.0 × 10[Formula: see text] M–6.25 × 10[Formula: see text] M. General trends were also studied for fluorescence quantum yields and lifetimes of these phthalocyanine compounds in tetrahydrofuran. The fluorescence of the synthesized unsymmetrical metal-free and metallophthalocyanines is effectively quenched by 1,4-benzoquinone (BQ) in THF. In-depth investigation of the electrochemical properties showed that nitro groups extended the reduction potentials.

Synthesis, characterization and gas sensing properties of novel homo and hetero dinuclear ball-type phthalocyanines

A ball-type homodinuclear Co(ii)–Co(ii) phthalocyanine (2) and ball-type heterodinuclear Co(ii)–Fe(ii) phthalocyanine (3) were synthesized and their gas sensing properties were investigated.

A conformationally stressed novel ball-type perylenediimide appended zinc(ii)phthalocyanine hybrid: spectroelectrochemical, electrocolorimetric and photovoltaic properties

The ZnPc-perylenediimide hybrid displayed a well-defined electrochromic behaviour and the best photovoltaic conversion efficiency observed with a Pc-based organic solar cell.

Synthesis and photophysical properties of a novel ethynyl zinc(II) phthalocyanine and its functionalized derivative with click chemistry

The synthesis of novel, symmetrical zinc(II) phthalocyanine (ZnPc) bearing four ethynylcyclohexyloxy terminal moieties was achieved by cyclotetramerization of novel 4-(2-ethynylcyclohexyloxy) phthalonitrile in pentanol in the presence of DBU and zinc acetate without any protective/deprotective chemistry. Subsequently, this new zinc(II) phthalocyanine derivative was reacted with 6-azido-hexanoic acid under "click-chemistry" conditions to give phthalocyanine-hexanoic acid conjugates linked by 1,2,3-triazole units. The new compounds have been characterized by using elemental analyses, UV-vis, FTIR, 1 H NMR and mass spectroscopic data. The aggregation properties of the compounds were investigated in different concentrations. General trends are also described for fluorescence quantum yields and lifetimes of novel zinc derivatives in tetrahydrofuran. The fluorescence of the tetrasubstituted zinc(II) phthalocyanine complexes is effectively quenched by 1,4-benzoquinone (BQ) in THF.

The synthesis, photophysical and dielectric properties of ball-type dinuclear zinc phthalocyanine

The synthesis of ball-type dinuclear Zn(II) phthalocyanine containing four 4,4′-(9H-fluorene-9,9-diyl)diphenol substituents at the non-peripheral position is presented. The structure of the synthesized compound was characterized using elemental analyzes, and UV-vis, FT-IR,1H NMR and mass spectroscopies. The ΦFvalue was 0.16 and ΦTvalue was 0.72. The complex showed reasonably long triplet lifetimes with τT7210 μs in DMSO. The frequency and temperature dependence of the dielectric properties of ZnPc were also investigated in the frequency range of 40–105Hz and in the temperature range of 300–440 °K. It has been observed that both dielectric constant ε′ and dielectric loss ε″ decrease with the rise in frequency as they increase with the rise in temperature. The decrease in ε′ with increasing frequency is attributed to the fact that as the frequency increases, the polarizability contribution from orientation sources decreases and finally disappears.

Synthesis, interface (Au/M2Pc2/p-Si), electrochemical and electrocatalytic properties of novel ball-type phthalocyanines

The phthalodinitrile derivative (3) was prepared by the reaction of 4,4'-(octahydro-4,7-methano-5H-inden-5-ylidene)bisphenol (1) and 4-nitrophthalonitrile (2) with dry DMF as the solvent in the presence of the base K(2)CO(3) by the method of nucleophilic substitution of an activated nitro group in an aromatic ring. The template reaction of 3 with the corresponding metal salts gave the novel bi-nuclear ball-type metallophthalocyanines, MPcs {M = Co (4), Cu (5), Zn (6)}. Newly synthesized compounds were characterized by elemental analysis, UV-vis, FT-IR (ATR), MALDI-TOF mass and (1)H-NMR spectroscopy techniques. The electronic spectra exhibit an intense π→π* transition of characteristic Q and B bands of the Pc core. The dielectric properties and interface between the spin coated films of 4-6 and a p-type silicon substrate have been studied by fabricating metal-insulator-semiconductor capacitors. The results indicated that the frequency dependence of the dielectric permittivity, ε'(ω), exhibits non-Debye type relaxation for all the temperatures investigated. The ac conductivity results indicated that the conduction mechanism can be explained by a hopping model at low temperatures (<430 K) and a free band conduction mechanism at high temperatures (≥430 K). The density of interface state calculations on these novel compounds showed that the combination of Au/4/p-Si is a promising structure with a high dielectric constant and a low interface trap density suitable for metal-oxide-semiconductor devices. The electrochemical properties of the Pc complexes were examined by cyclic voltammetry, differential voltammetry and controlled potential coulometry on platinum in non-aqueous media. The complexes showed ring-based and/or metal-based mixed-valence behaviours as a result of the remarkable interaction between the two Pc rings and/or metal centres. The mixed-valence splitting values for the complexes suggested that the mixed valence species are considerably stable. The Vulcan XC-72(VC)/Nafion(Nf)/4 modified glassy carbon electrode showed much a higher catalytic performance towards oxygen reduction than those of VC/Nf/5 and VC/Nf/6 modified ones.

Phthalocyanine with a giant dielectric constant

Compound 1 has been prepared by the reaction of 4-nitrophthalonitrile and trans-2-methoxy-4-(2-nitrovinil)phenol by the common method of nucleophilic substitution of an activated nitro group in an aromatic ring. The metallophthalocyanines 2, 3 were prepared by the reaction of a dinitrile derivative with Co(OAc)(2) or Zn(OAc)(2) in DMSO. The lutetium bis-(phthalocyaninato) complex 4 was obtained by treating the dinitrile derivative with lutetium acetate and DBU in 1-hexanol. The new compounds were characterized by elemental analyses, FT-IR, (1)H-NMR, MALDI-TOF MS and UV/Vis spectral data. The spectroscopic data of the new compounds were in accordance with the structures. The temperature and frequency dependence of dielectric and conduction properties of the spin coated film of compounds (2-4) have been studied by fabricating metal-Pc-metal structures. The results show that compound 2 has giant dielectric constant. At a low range of frequency and room temperature, ε' is found to be equal to 2.33 × 10(6), 1.53 × 10(4) and 1.03 × 10(4) for 2, 3 and 4, respectively. The giant dielectric behavior of 2 is mainly attributed to Maxwell-Wagner polarization. The obtained results also indicated that the frequency dependence of the dielectric permittivity, ε'(ω), exhibits non-Debye type relaxation for all temperatures investigated. The ac conductivity results gave a temperature dependent frequency exponent s. The results were compared with the prediction of the Quantum Mechanical Tunneling and Correlated Barrier Hopping models.

Synthesis, characterization, and electrochemical and electrical properties of novel mono and ball-type metallophthalocyanines with four 9,9-bis(4-hydroxyphenyl)fluorene

The new mono-nuclear 4-5 and ball-type homo-dinuclear 6 phthalocyanines have been synthesized from the corresponding phthalodinitrile derivative 3. The synthesized compounds have been characterized by elemental analysis, UV-vis, IR,(1)H-NMR and MALDI-TOF-mass spectroscopies. The redox behaviours of the complexes were identified by cyclic voltammetry and square wave voltammetry. The temperature dependence of the electronic properties of compounds and adsorption of SO(2) on thin film of 6 were investigated by conductivity measurements using an interdigital transducer structure on glass substrate. Dc conductivity, measured between 300-475 K, is thermally activated with the activation energy ranging between 0.67 and 0.90 eV. The ac conductivity is found to vary with frequency, ω, as ω(s) in which the frequency exponent s decreases with temperature suggesting a hopping conduction mechanism for all compounds. The SO(2) sensing result showed that the spin coated film of 6 exhibits very good SO(2) sensing properties, fast response and recovery rate, high sensitivity and good repeatability.

Synthesis and characterization, novel across adjacent ring formed phthalocyanine

Novel mononuclear Zn(ii) 4, Co(ii) 5 and Cu(ii) 6 metallophthalocyanines have been synthesized from 4,4'(ethane-1,1-p-phenol-2,2-p-phenoxy)phthalonitrile 3, which can be obtained by the reaction of 4-nitrophthalonitrile 1 with 1,1,2,2-tetrakis(p-hydroxy-phenyl)-ethane 2. The target water-soluble derivatives of 7-9 were acquired from a boiling suspension of the compounds in aqueous 20% KOH solution. The synthesized complexes have been characterized by UV-vis, IR, (1)H NMR and MALDI-TOF-mass spectroscopies. In addition, the geometric and electronic structures of 2-6 were investigated by ab initio/DFT quantum mechanical calculations using the Gaussian 03 program with HF theory at the B3LYP/3-21G level. The redox properties of the complexes 4-6 were examined by cyclic voltammetry on platinum in DMSO/TBAP. These complexes displayed one-electron metallophthalocyanine-based and multi-electron hydroxyphenyl-based redox processes. The effect of temperature on the d.c. conductivity and impedance spectra of spin coated films of compounds were investigated at the temperatures between 300-452 K and in the frequency range of 40-105 Hz. Thermally activated conductivity dependence on temperature was observed for all compounds. A.c. results indicated that conduction mechanism can be explained by classical hopping barriers mechanism for all films.