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Complexes derived from meso-tetra(thienyl)porphyrins (TThP) and meso-tetra(pyridyl)porphyrin (TPyP) containing peripheral ruthenium complexes with general formulas {TPyP[RuCl(dppb)(5,5'-Mebipy)]4}(PF6)4, {TThP[RuCl(dppb)(5,5'-Mebipy)]4}(PF6)4, and {TThP-me-[RuCl(dppb)(5,5'-Mebipy)]4}(PF6)4 [5,5'-Mebipy = 5,5'-dimethyl-2,2'-bipyridine and dppb = 1,4-bis(diphenylphosphino)butane] were synthesized and characterized by spectroscopy techniques (1H- and 31P{1H}-NMR, IR, UV/vis, fluorescence, and electron paramagnetic resonance (EPR)), cyclic voltammetry, coulometry, molar conductivity, and elemental analysis. Voltammetry and UV/vis studies demonstrated differentiated electronic properties for ruthenium appended with TThP and TThP-me when compared to ruthenium appended with TPyP. The UV/vis analysis for the ruthenium complex derived from TThP and TThP-me, as well as the Soret and Q bands, characteristics of porphyrins, showed a band at 700 nm referring to the Ru → S electronic transition, and porphyrin TThP-me showed another band at 475 nm from the Ru-N transition. The attribution of these bands was confirmed by spectroelectrochemical analysis. Cyclic voltammetry analysis for the ruthenium complex derived from TPyP exhibited only an electrochemical process with E1/2 = 0.47 V assigned to the Ru(II)/Ru(III) redox pair (Fc/Fc+). On the other hand, two processes were observed for the ruthenium complexes derived from TThP and TThP-me, with E1/2 around 0.17 and 0.47 V, which were attributed to the formation of a mixed valence tetranuclear species containing Ru(II) and Ru(III) ions, showing that the peripheral groups are not oxidized at the same potential. Fluorescence spectroscopic experiments show the existence of a mixed state of emission in the supramolecular porphyrin moieties. The results suggest the formation of Ru(II)-Ru(III) mixed valence complexes when oxidation potential was applied around 0.17 V in the {TThP[RuCl(dppb)(5,5'-Mebipy)]4}(PF6)4 and {TThP-me-[RuCl(dppb)(5,5'-Mebipy)]4}(PF6)4 species.

Many studies about porphyrins have emerged in recent years, including studies using porphyrins as building blocks for supramolecular assemblies. Understanding new solid state forms of porphyrins and the elucidation of their structures can have remarkable benefits for nanoscience and synthetic biology. In this study, a new pseudopolymorph of cobalt (II) meso-tetraphenylporphyrin, (CoTPP), was synthesized in a known one-pot reaction, rather than using many-step conventional methods, was isolated and was characterized for the first time by low-temperature single crystal X-ray diffraction. It is a nonstoichiometric solvate assembled into dichloromethane channels. The most striking feature of this structure is the conformation adopted by the porphyrin macrocycle. In contrast to the non-solvated form of CoTPP that exhibits a ruffled core distortion and crystallizes in the tetragonal space group I-42d, this solvated form has been crystallized in the triclinic space group Pī and shows a distinct saddle-shaped macrocycle distortion. In the triclinic form, the conformation of one of the four phenyl rings is remarkably different from the others. A potential energy surface scan of the torsional angles around the bonds between this phenyl moiety and the macrocycle of CoTPP in both the non-solvated and the solvate forms demonstrates that the saddle-shaped macrocycle distortion depends on the unusual phenyl conformation. The distortion is responsible for the symmetry decrease in the channel solvate form, causing a loss of the 4-fold rotoinversion axis observed in the non-solvated tetragonal phase, which has identical phenyl conformations.

Porphyrin and phthalocyanine macrocycles with ionic substituents can form mixed assemblies with interesting electronic properties for potential application on the development of new devices. This paper reports the synthesis, isolation and purification of heteroaggregate formed by cobalt(II) 4,4′,4″,4‴-tetrasulfophthalocyanine (CoTsPc) and cobalt(II) tetrakis(N-methyl-4-pyridyl)porphyrin (CoTMPyP), followed by its spectroscopic characterization. Spectroscopic titration, performed with a CoTsPc water/acetone solution, allowed the use of Job's method for determination of the heteroaggregates stoichiometry. The Job's plot revealed the formation of only one predominant heterocomplex in solution, containing two CoTsPc molecules in terminal positions and a central CoTMPyP one. For the first time, a method for isolation and purification of a mixed ionic array has been reported in the literature. The triad's electronic spectrum is quite different from the sum of the macrocycles isolated spectra, due to the overlap of their electronic densities and a charge transfer process between CoTsPc and CoTMPyP.

Phthalocyanine compounds have been widely investigated as candidate materials for technological applications, which is mainly due to their thermal stability and possibility of processing in the form of thin films. In most applications, the controlled growth of thin films with high crystalline quality is essential. In this study, zinc phthalocyanine (ZnPc) thin films were prepared by evaporation on glass and Au-coated glass substrates with subsequent annealing at different temperatures in ambient atmosphere. The morphological and structural features of 80 nm thick zinc phthalocyanine films were investigated, evidencing an α → β phase transformation after annealing the films at 200 °C, as indicated by UV–Vis spectroscopy and FTIR analyses. A better uniformity of the annealed films was also evidenced via AFM analysis, which may be of importance for applications where film homogeneity and excellent optical quality are required.

The effects of laser irradiation and annealing of rhodium phthalocyanine Langmuir–Blodgett films deposited on quartz and Au-covered glass substrates were studied with ultraviolet-visible and Fourier transform infrared spectroscopy, X-ray diffraction and atomic force microscopy. We found that laser irradiation and annealing produce very similar results attributed to the heating effect in both cases and produce different results in different atmospheres (air and Helium). Changes observed in films treated at 200 °C in an inert atmosphere are attributed to a molecular rearrangement of the films associated with the destruction of J aggregates. Films treated in similar conditions in air show, besides this effect, possible oxidation and loss of molecules. A remarkable decrease of roughness was observed when the films are annealed at 100 °C in He, attributed to the evaporation of water molecules trapped in the Langmuir–Blodgett films.

The degree of crystalline order of evaporated and cast palladium phthalocyanine films was investigated before and after they were submitted to a voltammetric process. X-ray diffraction and UV-vis spectroscopy measurements demonstrated that the electrochemical treatment improves the crystalline quality of the films. The X-ray results revealed an increase of the average size of the crystallites composing the films as well as a decrease in the spacing between the lattice planes in the direction perpendicular to the surface of the film. Optical measurements showed that the electrochemical treatment also introduces an appreciable degree of in-plane ordering. These improvements of crystalline order are observed in both types of films, cast and evaporated, which indicates that the ordering is a direct consequence of the electrochemical treatment and not of the method used for the film deposition.

The degree of mixing and surface coverage in Langmuir−Blodgett (LB) films of ytterbium bisphthalocyanine (YbPc2) mixed with stearic acid (SA) has been probed using atomic force microscopy (AFM) and micro-Raman imaging. The morphologies extracted for LB films at the nanometer (AFM) and micrometer (micro-Raman) scales are consistently in good agreement. The results show that a 5-layer mixed LB film with 75/25% YbPc2/SA (relative content by weight) displays smaller and more homogeneous distribution of aggregates compared with a 5-layer mixed film of 25/75% YbPc2/SA. Raman microscopy of neat LB films of ytterbium bisphthalocyanine (YbPc2) and mixed YbPc2/stearic acid LB films deposited on glass and silver islands is reported. Resonance Raman scattering (RRS), surface-enhanced resonance Raman scattering (SERRS), and surface-enhanced Raman scattering (SERS) were obtained using laser lines at 633 and 780 nm. The enhanced (SERRS) and unenhanced (RRS) resonance Herzberg−Teller spectra of neat YbPc2 LB films and mi...

Langmuir–Blodgett (LB) films from pure ytterbium bisphthalocyanine (YbPc 2 ) and mixtures of YbPc 2 and stearic acid have been produced, whose cyclic voltammetric response displays a redox activity strongly dependent on the scan rate and film thickness. Successive redox reactions are accompanied by color variations upon small changes in the electrode potential range which make these films promising for multi-color devices.

Calix[4]resorcinarenes octafunctionalized with methyl α-acetate (CALES) or methyl α-acetamide (CALAM) have been used to form Langmuir-Blodgett (LB) films on several different substrates. Spectroscopic characterization of these species as solids, solutions, and LB films were carried out using FT-IR, FT-Raman, UV-visible, and fluorescence spectroscopies. Considering the spectroscopic evidence, the conformation of both CALES and CALAM in the LB films was found to be the flattened cone. It has been shown that the presence of metal cations in the subphase results in incorporation of cations into the LB film. The film organization of the octafunctionalized calix[4]resorcinarene in the film is determined by the metal cation.

The vascular accesses to hemodialysis patients usually are through arteriovenous fistula (AVF) or synthetic grafts. The analyses of recirculation zones, stagnation points, secondary flow and low and high shear stress are very important points to study for understand the hemodynamic local in arteriovenous fistula. In this work, it was analyzed through computational fluid dynamics the streamlines in AVF and it was compared with the literature results. The flow patterns were visualized under steady and unsteady condition with Reynolds number ranging from 100 up 600. The results obtained from CFD were very similar with the literature results. The flow becomes more chaotic when the Reynolds number increases. Vortex can be seen in anastomosis region, occupying all transversal section of the artery. Thus, the results obtained using CFD look like the results obtained experimentally.

The processing of macrocyclic phthalocyanines (Pc) in the form of thin, nanostructured films has been usually carried out via evaporation techniques, owing to the low solubility exhibited by these compounds. The fabrication of Pc ultrathin films via the Langmuir–Blodgett technique may be advantageous from a technological point of view, since parameters such as film architecture and organization can be achieved without post-thermal treatments. In this study, a parent zinc phthalocyanine (ZnPc) and its fluorinated derivative (F 16 ZnPc) were synthesized and manipulated in the form of LB films. The morphological and structural features of ZnPc and F 16 ZnPc Langmuir–Blodgett films containing up to 31 layers were investigated using Fourier transform infrared spectroscopy (FTIR), micro-Raman spectroscopy and X-ray diffraction analyses and were compared to ZnPc and F 16 ZnPc cast films. The interplanar distance obtained by X-ray specular reflection decreases from 12.64 A for ZnPc to 12.16 A for F 16 ZnPc. FTIR spectra indicated absence of order in the LB films from ZnPc and F 16 ZnPc, at least in the direction perpendicular to the substrate surface. Therefore, the order observed in the X-ray diffractograms means that the molecules might be organized in crystallites that are randomly oriented in the film.

Rhodium phthalocyanine (RhPc) was synthesized and ultra thin Langmuir–Blodgett (LB) films of RhPc were successfully fabricated. The LB film characterization was carried out using both UV–vis absorption spectra and Raman scattering. The Raman spectroscopy was carried out using 633 and 780 nm laser lines. LB films were deposited onto Ag nanoparticles to achieve the surface-enhanced pre-resonance Raman scattering (pre-SERRS) and surface-enhanced Raman scattering (SERS) for both laser lines, respectively, which allowed the characterization of the RhPc ultra thin films. The morphology of the LB RhPc neat film is extracted from micro-Raman imaging.

A systematic study is reported on the monolayer characteristics of ytterbium bisphthalocyanine (YbPc 2 ) at the air-water interface, using surface pressure and surface potential isotherms. The influence of various experimental parameters was analyzed, including compression speed, spreading volume, position of the pressure sensor, and subphase temperature. The area per molecule decreased with increasing spreading volumes. Interestingly, the position of the Wilhelmy plate affected the pressure-area isotherms, which does not occur for traditional aliphatic compounds. No significant influence from the subphase temperature was detected. Upon varying the compression speed, the surface potential curve and the collapse pressure were affected, even though the area per molecule remained practically the same. When these monolayers with distinct dipole moments were transferred onto a gold-coated glass substrate, the resulting multilayer LB films exhibited the same surface potential, probably due to molecular rearrangement upon transfer.

Electroactive films of iron tetrasulfonated phthalocyanine (FeTsPc) were assembled via the electrostatic layer-by-layer technique (LBL), in which FeTsPc layers were alternated with the polycationic poly(allylamine hydrochloride) (PAH). The multilayer formation was monitored via UV-Vis spectroscopy by measuring the increase in the Q Band of FeTsPc at 676 nm. Film thickness was estimated by profilometry as ca. 10 A per bilayer. Fourier transform infrared and UV-Vis absorption spectroscopy suggested specific interactions between FeTsPc and PAH. Cyclic voltammograms showed reproducible pairs of oxidation-reduction peaks at 0.92 mV and 0.70 mV, respectively, for a 50-bilayer PAH/FeTsPc film at 50 mV/s (vs Ag/AgNO 3 ).

We describe the optical properties of ytterbium bis-phthalocyanine (YbPc 2 ) dissolved in chloroform. A six-energy-level diagram is proposed to establish the population dynamics when laser pulses at 532nm are employed.

Monolayer characteristics of ytterbium and samarium phthalocyanines (YbPc 2 and SmPc 2 ) have been investigated by surface pressure and surface potential isotherms. It has been shown that the metal ion in the phthalocyanines can cause marked differences in the monolayer properties. The different monolayer characteristics of YbPc 2 and SmPc 2 may possibly be ascribed to either the extent of aggregation or the symmetry of the metallophthalocyanines.