Aggregation of lead phthalocyanine in blends with polycarbonate

The blends of a nonlinear optical dye with polycarbonate are described and comparisons are made with solutions of the dye in chloroform. Absorption spectra of blends with up to 1 wt % lead tetracumylphenoxy phthalocyanine showed the dye to be primarily in the monomer form. The monomer absorption spectrum and the measured extinction coefficient replicated those in chloroform solution. As the dye concentration increased to 20 wt %, the monomer intensity decreased and new spectral features characteristic of the dimer appeared. The spectra were resolved into contributions of monomer and dimer, and the concentration effect was analyzed according to the monomer/dimer equilibrium. Much higher monomer concentrations were achieved in polycarbonate blends compared to chloroform solutions. It was concluded that when the blends were quenched from the melt, the equilibrium established at the melt temperature was preserved in the solid state glass. Quenching the blend from different melt temperatures confirmed this interpretation. Extrapolation of the temperature dependent equilibrium constant to 25°C yielded a value close to that reported for chloroform solution at 25°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 104: 464–469, 2007     

Theoretical aspects of the structure of polymeric phthalocyanines

Recent work on theoretical aspects of the structure of planar and stacked polymeric phthalocyanines is discussed. The regular structure of planar bridged polymeric phthalocyanines can be described mathematically by assuming the whole molecule placed in a Cartesian coordinate system. The resulting structure model agrees with analytical data. For example, the equationn=64/v ², wheren is the number of phthalocyanine macrocycles in a planar bridged polymeric phthalocyanine andv (derived from IR spectra) is the number of end group-carrying bis(phthalonitrile) units per phthalocyanine ring, is derived from this model. An extended structure model yields fractal dimensions for planar bridged polymeric phthalocyanines. The positions of the bridges or substituents in bridged planar polymeric phthalocyanines cause different symmetries and different numbers of positional isomers for which equations are derived. Linear bridged and rectangular planar polymeric phthalocyanines have approximatelyi _d/4 isomers, while square bridged planar polymeric phthalocyanines possess abouti _d/8 isomers. Stacked substituted polymeric phthalocyanines have approximatelyi _d/16 isomers, wherei _d is the number of isomers which can be drawn on paper (i _d=2 ^m ;m is the number of substituted phathalonitrile monomers in the polymeric phthalocyanine). The possible symmetries for polymeric planar and stacked phthalocyanines are discussed. Previous discussions of symmetry and numerical notation of stacked polymeric phthalocyanines with tetrasubstituted phthalocyanine rings are extended in this work.Presented in part as a poster at the IUPAC 5th International Conference on Macromolecule-Metal Complexes, Bremen, Germany, 1993.     

Single Layer of Polymeric Cobalt Phthalocyanine: Promising Low‐Cost and High‐Activity Nanocatalysts for CO Oxidation

The catalytic behavior of transition metals (Sc to Zn) combined in polymeric phthalocyanine (Pc) is investigated systematically by using first‐principles calculations. The results indicate that CoPc exhibits the highest catalytic activity for CO oxidation at room temperature with low energy barriers. By exploring the two well‐established mechanisms for CO oxidation with O₂, namely, the Langmuir–Hinshelwood (LH) and the Eley–Rideal (ER) mechanisms, it is found that the first step of CO oxidation catalyzed by CoPc is the LH mechanism (CO + O₂ → CO₂ + O) with energy barrier as low as 0.65 eV. The second step proceeds via both ER and LH mechanisms (CO + O → CO₂) with small energy barriers of 0.10 and 0.12 eV, respectively. The electronic resonance among Co‐3d, CO‐2π*, and O₂‐2π* orbitals is responsible for the high activity of CoPc. These results have significant implications for a novel avenue to fabricate organometallic sheet nanocatalysts for CO oxidation with low cost and high activity.     

Effects of peripheral chloro substitution on the photophysical properties and in vitro photodynamic activities of galactose-conjugated silicon(IV) phthalocyanines

A series of silicon(IV) phthalocyanines with two axial isopropylidene-protected galactose moieties and one, two, or eight chloro group(s) on the periphery of the macrocycle have been synthesised and spectroscopically characterised. The photophysical properties and in vitro photodynamic activities of these compounds have been studied and compared with those of the nonchlorinated analogue. All the compounds, with the exception of the octachlorinated counterpart which has a limited solubility, are essentially nonaggregated in N,N-dimethylformamide. The fluorescence quantum yield decreases and the singlet oxygen quantum yield increases as the number of chloro substituent increases, which is in accord with the heavy-atom effect. The non-, mono-, and dichlorinated phthalocyanines formulated with Cremophor EL are all photodynamically active against HT29 human colon adenocarcinoma and HepG2 human hepatocarcinoma cells with IC(50) values ranging from 0.03 to 1.05 microM. The photocytotoxicity as well as the efficiency to generate intracellular reactive oxygen species decrease along this series because of the increase in aggregation tendency upon chloro substitution. The nonchlorinated analogue exhibits the highest potency and can target the lysosomes of HT29 cells, whereas the monochlorinated counterpart is not localised in the lysosomes.     

The synthesis and fluorescence behaviour of new unsymmetrically mono-functionalized carboxy Ge, Ti and Sn phthalocynines

This work reports on the synthesis and fluorescence behaviour of novel unsymmetrically substituted monocarboxy germanium ((OH)₂GeMCPc, 3), titanium (OTiMCPc 4) and tin ((ac)₂SnMCPc, 5) phthalocyanines. The fluorescence quantum yields ranged from 0.09 to 0.14. The fluorescence lifetimes were found to be higher for the complex with higher fluorescence quantum yield value. Higher fluorescence quantum yields and lifetimes were obtained for the (ac)₂SnMCPc complex (5), followed by OTiMCPc complex (4), and the lowest fluorescence quantum yield and lifetime were observed for (OH)₂GeMCPc (3).     

四叔丁基金属酞菁化合物的合成

本文以邻-二甲苯为原料,经烷基化、氧化和脱水缩合合成了4-叔丁基邻苯二甲酸酐,然后将4-叔丁基邻苯二甲酸酐在钼酸铵催化下与尿素、无水金属氯化物作用合成了四叔丁基酞菁铁、钴、镍、镁化合物。对合成产物分别用核磁共振、红外光谱或元素分析确证结构。     

Generalized Synthesis of Ultrathin Cobalt‐Based Nanosheets from Metallophthalocyanine‐Modulated Self‐Assemblies for Complementary Water Electrolysis

The development of effective approaches for preparing large‐area, self‐standing, ultrathin metal‐based nanosheets, which have proved to be favorable for catalytic applications such as water electrolysis, is highly desirable but remains a great challenge. Reported herein is a simple and versatile strategy to synthesize ultrathin Co₃O₄ and CoP NSs consisting of close‐packed nanoparticles by pyrolyzing cobalt(II) phthalocyanine/graphene oxide (CoPc/GO) assemblies in air and subsequent topotactic phosphidation while preserving the graphene‐like morphology. The strong π–π stacking interactions between CoPc and GO, and the inhibiting effect of the tetrapyrrole‐derived macrocycle for grain growth during the catalytic carbon gasification contribute to the NSs forming. The resulting homologous Co₃O₄ and CoP NSs display outstanding catalytic activity in alkaline media toward the oxygen evolution reaction and the hydrogen evolution reaction, respectively, ascribed to the richly exposed active sites, and the expedited electrolyte/ion transmission path. The integrated asymmetrical two‐electrode configuration also presents a superior cell voltage of 1.63 V at 10 mA cm^?2 for overall water splitting, accompanied with the excellent durability during long‐term cycling. Further evidences validate that this strategy is appropriate to fabricate graphene‐like ultrathin NSs of many other metal oxides, such as Fe₂O₃, NiO, MoO₃, and mixed‐metal oxides, for various applications.