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The polymorphism and isomorphism of Ge(OH)₂Pc and Si(OH)₂Pc (Pc: phthalocyanine ligand) are reported as well as those of the polymeric molecules of (GeOPc)_n and (SiOPc)_n. The polymeric Pcs were produced through dehydration polymerization by heating the respective monomer of Ge(OH)₂Pc or Si(OH)₂Pc. We also report the thin film structures of these phthalocyanine derivatives and discuss the similarities and differences in the structures formed by vacuum deposition, in relation to the coordinating metal species.

The synthesis of three novel porphyrins (that are models for mesoporphyrin) requires the synthesis of eight new pyrroles, one new alkyl-3-oxohexanoate and two new dipyrromethanes. The new porphyrin free bases have hydrophobic substitution patterns different from that in mesoporphyrin. We are seeking amphilic porphyrins that will form Langmuir–Blodgett (LB) multilayers without recourse to either long-chain alkyl substituents or fatty acid additives. In this way the influence of the conjugated tetrapyrrole unit on the properties of the multilayer films can be maximized. We report multilayer deposition for porphyrins having the following substituents: CH₃, C₂H₅, n-C₃H₇, (CH₂)₂COOMe; no additives such as stearic acid, cadmium stearate or mesitylene are required, Y-type deposition being exhibited by the simply substituted pure methyl esters. The variations in proton NMR chemical shift with concentration are reported and the action spectrum of an LB film of a porphyrinato-Zn(II) complex is described. Our observations and conclusions are in sharp (and optimistic) contrast with those of H. Chou et al. (J. Phys. Chem. 98, 383 (1994)), who found that in the absence of steric constraints from bulky aliphatic chains the Langmuir films are so rigid that either no multilayers or multilayers of poor quality are given. We obtain good-quality multilayers (60 layers) for porphyrins bearing eight small substituents.

Polyaniline (PA) and aniline black (AB) were prepared in powder form by the chemical method of oxidative polymerization, from which free-standing thin films were obtained by solvent evaporation using N-methyl pyrrolidinone (NMP). The thin films contained 2, 4, 6 or 8 wt% AB. Electrical measurements showed that the samples containing 4% AB exhibited the highest photoconductivity of the four concentrations. Thus there appears to be a critical ratio of PA to AB for maximum photoconductivity. Annealing up to 570 K has little effect on the conductivity. Upon adding a small quantity of copper phthalocyanine (CuPc) to the PA + AB, the electrical conductivity increased considerably and the optical absorption was extended from the UV to the near IR. The electrical conductivity mechanism is a consequence of a redox process, since AB is the oxidized state of PA and, upon illumination, there is an exchange of charge carriers. The extension of the range of optical absorption upon addition of CuPc is interpreted to suggest that CuPc photosensitizes the material and enhances the carrier transport process in the redox couple. The activation energy from the temperature-dependent conductivity and the band gap from the electrolyte electroreflectance method were determined. The activation energy for 0.4% CuPc is lowest (0.52 eV) and the corresponding band gap is determined to be 3.0 eV. This organic compound could be a good candidate for inexpensive, reliable and efficient solar energy-converting devices.

Soluble metal-free and Cu-, Ni- and Co-substituted 3,4-tetrapyridinoporphyrazines (Tpps)5–8 have been synthesized. Poly(methyl methacrylate) (PMMA) spin coated and Langmuir–Blodgett (LB) films containing these compounds have been prepared. Third-harmonic generation (THG) was used to measure the third-order-non-linear optical susceptibility of both types of films at 1.064 μm. For the spin-coated samples a strong enhancement of the THG response was found on increasing the Tpp concentration of the chlorobenzene solution used to prepare the samples. The enhancement was associated with the formation of molecular aggregates in the solution which were ‘frozen’ into the films. In order to facilitate comparison, the final Tpp concentration in the PMMA films was kept approximately constant in all cases. Metal incorporation (particularly Co) in the macrocycle strongly enhances the THG susceptibility of the films prepared using concentrated solutions, whereas the effect is efficiently inhibited in those obtained from less concentrated solutions. We conclude that the enhancement in the THG response occurs via the influence of the metal on the Tpp aggregation process in the solution. For the LB films the THG results are more comparable with those of the spin-coated samples prepared using low-concentration solutions. This indicates that dimers, previously identified in the LB films, and possibly other small-size oligomers are formed in the low-concentration Tpp solutions. On the other hand, larger aggregates should be formed in the spin-coated samples prepared from high-concentration solutions.

The optical properties of palladium phthalocyanine in dimethylformamide, toluene, acetonitrile, and dichloromethane solutions were studied in the visible range of energy. Palladium phthalocyanine in organic medium presented itself as a mixture of monomeric and dimeric species in equilibrium, and it was only in dichloromethane that the monomeric, non-aggregated form predominated. Palladium phthalocyanine films were prepared by casting, and studied by cyclic voltammetry and spectroelectrochemistry. The films showed an electrochromic response from blue to purple, and stability that depended on the applied potential. Electrochemical quartz crystal microbalance experiments indicated that the film exfoliates into solution after applying high values of final potentials. Raman spectroscopy was used to structurally characterize the palladium phthalocyanine film, which showed a central metal with +2 oxidation state that is not affected even when the film is oxidized.

In this work, the investigation of structural features, spectral and electrical properties of spin-coated films of substituted lutetium bisphthalocyanine Lu(Pc(SR)₈)₂, where R = -C₆H₁₃ was carried out. The current-voltage characteristics of ITO/Lu(Pc(SR)₈)₂/Al film sandwich structures were measured over the temperature range 120–380 K. AC electrical properties, mainly the dependence of conductance and capacitance on frequency and temperature are also discussed. Structural and electrical properties of anthracene-doped Lu(Pc(SR)₈)₂, films have also been investigated. Furthermore, optical properties of thin films of pure and anthracene-doped Lu(Pc(SR)₈)₂ films were also studied using spectroscopic ellipsometry, while atomic force microscopy (AFM) was used to study changes in films' morphology of doped films and compared with that of undoped films. Doping Lu(Pc(SR)₈)₂, films with anthracene is shown to lead to an increase in films' conductivity. These studies will provide full understanding of the physical properties of the Lu(Pc(SR)₈)₂, thin films, both doped and undoped, with the aim of exploitation in electronic device applications, such as fabrication of all organic solar cells.

In the present work, the optical response of CoPcF₁₆ films upon exposure to ammonia vapor in the concentration range 50 to 1000 ppm was measured by total internal reflection ellipsometry. It was demonstrated that the sorption of NH₃ molecules causes substantial shift of the Δ(λ) spectrum which is determined by the increase in film thickness and change of its optical parameters. It was found that the CoPcF₁₆ films deposited at substrate temperature of 220 °C are characterized by larger grains and more developed surface demonstrating higher optical response than films deposited at substrate temperature of 60 °C. In order to gain an insight into the sorption mechanism at molecular level, we have studied the interaction of ammonia vapor with hexadecafluorinated cobalt phthalocyanine using infrared spectroscopy. It was shown that the detection of ammonia was found to be governed primarily by coordination to the metal center.

Porphyrin nanorods (PNR) have been fabricated by electrostatic self-assembly of two oppositely charged porphyrin molecules. The free base meso-tetra-(4-phenylsulphonate) porphyrin (TPPS${}_4)$ served as negatively charged counterpart for the positively charged metallo meso-tetra(4-$N$-methylpyridyl) porphyrins (MTM’PyP) with either Sn, Co, Mn or In as central metal M. Films of PNR were prepared on fluorine doped tin oxide glass sheets (FTO) by using a drop-dry method. The electronic spectra revealed J-aggregation of the charged molecules for the colloid PNR as well as for the films. Transmission electron microscopy confirmed the formation of porphyrin nanorods. The laser microscope and scanning electron microscope (SEM) images of the PNR/FTO films showed the formation of three kinds of structures in the films which consist of differently branched or linear needles with their main axis grown in the direction of the solvent flow during preparation. During cyclic voltammetry either applying negative potentials from 0.0 V to -1.0 V or positive potentials from 0.0 V to $+$2.2 V irreversible reduction or oxidation reactions were detected for the films. Consistently, SEM images taken following cyclic voltammetry showed the disintegration of the PNR on the films into smaller subunits. Spectroelectrochemical measurements showed the formation of porphyrin anionic radicals during oxidation by a decrease in the absorption intensities and broadening of spectra with an additional band appearing around 900 nm. A similar trend was observed when negative potentials were applied but in this case the cationic radical was produced. In both cases the decrease of the intensity of the J-aggregate confirms a loss of intermolecular coupling, again consistent with the smaller subunits observed in SEM analysis.

This work reports on synthesis and characterizations of Ga(III) and In(III) complexes, formed by 2,3-bis[2$\prime$-(2$\prime \prime$-hydroxyethoxy)ethoxy]-9,10,16,17,23,24-hexa-$n$-butoxy phthalocyanine (1H₂) coordinating acetatoindium(III) (1InOAc) and hydroxogallium(III) (1GaOH) Photophysical properties of hydroxogallium(III) phthalocyaninate 1GaOH and acetatoindium(III) phthalocyaninate 1InOAc were studied by UV-vis, fluorescence spectroscopy and time-resolved methods. The nonlinear absorption of the complexes was studied using the Z-scan technique at 532 nm and 10 ns pulse in DMSO and in thin films formed by composite with poly(bisphenol A carbonate) — PBC. The magnitude of absorption coefficients and other nonlinear optical parameters estimated in this work showed that complex 1InOAc exhibited the strongest nonlinear optical behavior in comparison with 1GaOH in solution and a reverse tendency when embedded in PBC thin films. DFT calculations were used to rationalize these results.

In this work, metal free, zinc and copper tetraphenyl porphyrin thin films were employed as substrates to study their interaction with glycine, serine, glutamate, lysine and argynine amino acids in order to investigate the effect of the metallic center and the amino acid characteristics in the adsorption phenomena. The amount of amino acid adsorbed on the films was quantified by using the Ruhemann method. Adsorption isotherms were obtained and analyzed in order to predict the adsorption mechanism for each case. In addition, the morphology of the films was investigated before and after the amino acid immersion by using scanning electron and atomic force microscopies. On the other hand, dynamic contact angle measurements were performed to monitor the spreading phenomena and changes in the hydrophobic nature of the surfaces after the amino acid interaction. From the results, it was observed that the largest deposited amino acid on all three surfaces corresponded to the positively charged compounds, while serine was the lowest adsorbed amino acid in all cases. These results can be attributed to electronic interactions between the amino acids’ lateral chains and the electronic $\pi$ distribution of the porphyrin macrocycle ring, and they provide important information regarding the amino acid selectivity of adsorption on tetraphenyl porphyrin films.

A single crystal of (5,10,15,20-tetraphenylporphyrinato)-silver was obtained and its structure reported. Using direct growth on quartz substrates method, a crystal thin film was obtained and the film’s morphology was investigated by atomic force microscopy. The nonlinear absorption properties of the film were studied using open aperture $Z$-scan technique by picosecond laser pulses at different fluence at wavelength 532 nm, nonlinear saturable absorption behavior was observed. Time-dependent unrestricted Hartree-Fock with the basis set LanL2DZ was used in computing the linear and non-linear optical properties of (5,10,15,20-tetraphenylporphyrinato)-silver.