Metal phthalocyanines magnetism

Randin, in a recently-published paper 44>, investigated solely on the basis of results from the literature the relationship between electrocatalytic activity for 2 reduction on the one hand, and oxidation potential, magnetic moment, and catalytic properties in gas-phase reactions on the other. It was found for the transition-metal phthalocyanines that magnetic moment and activity for the dehydrogenation of cyclohexanedione increase together with the activity of the phthalocyanines for 2 reduction, while the oxidation potential becomes less. The last fact can be seen from Fig. 29, in which the first oxidation potentials in 1-chlomaphthalene, measured by Manassen and Bar-Ilan 45>, are plotted against electrochemical activity. This result shows that the more easily an electron can... 

History. Braun and Tschemak [23] obtained phthalocyanine for the first time in 1907 as a byproduct of the preparation of o-cyanobenzamide from phthalimide and acetic anhydride. However, this discovery was of no special interest at the time. In 1927, de Diesbach and von der Weid prepared CuPc in 23 % yield by treating o-dibromobenzene with copper cyanide in pyridine [24], Instead of the colorless dinitriles, they obtained deep blue CuPc and observed the exceptional stability of their product to sulfuric acid, alkalis, and heat. The third observation of a phthalocyanine was made at Scottish Dyes, in 1929 [25], During the preparation of phthalimide from phthalic anhydride and ammonia in an enamel vessel, a greenish blue impurity appeared. Dunsworth and Drescher carried out a preliminary examination of the compound, which was analyzed as an iron complex. It was formed in a chipped region of the enamel with iron from the vessel. Further experiments yielded FePc, CuPc, and NiPc. It was soon realized that these products could be used as pigments or textile colorants. Linstead et al. at the University of London discovered the structure of phthalocyanines and developed improved synthetic methods for several metal phthalocyanines from 1929 to 1934 [1-11]. The important CuPc could not be protected by a patent, because it had been described earlier in the literature [23], Based on Linstead s work the structure of phthalocyanines was confirmed by several physicochemical measurements [26-32], Methods such as X-ray diffraction or electron microscopy verified the planarity of this macrocyclic system. Properties such as polymorphism, absorption spectra, magnetic and catalytic characteristics, oxidation and reduc-... 

To date there has been no report of observation of magnetic order of 4/ metal phthalocyanines in solid state. However, in 2003, it was revealed that some of lanthanide phthalocyanine complexes exhibit an intriguing property as SMM, a relatively new class of magnetic compounds [29,30], The SMMs are the paramagnetic... 

Mack, J. and Stillman, M.J. (2003) Electronic structure of metal phthalocyanine and porphyrin complexes from analysis of the UV-visible absorption and magnetic circular dichroism spectra and... 

Poly(CuPc) Poly(CoPc) Poly(NiPc) Sheet polymers of metal phthalocyanines insoluble electronic spectra, magnetic susceptibility, electrical conductivity, x ray diffraction discussed. [168]... 

Zhang YY, Du SX, Gao H-J (2011) Binding configuration, electronic structure, and magnetic properties of metal phthalocyanines on a Au(l 11) surface studied with ab initio calculations. Phys Rev B 84 125446-125454... 

These results illustrate that electrochemical techniques can be employed to synthesize a vast range of [Si(Pc)0]n-based molecular metals/conductive polymers with wide tunability in optical, magnetic, and electrical properties. Moreover, the structurally well-defined and well-ordered character of the polymer crystal structure offers the opportunity to explore structure/electro-chemical/collective properties and relationships to a depth not possible for most other conductive polymer systems. On a practical note, the present study helps to define those parameters crucial to the fabrication, from cheap, robust phthalocyanines, of efficient energy storage devices. 

Abstract In this chapter, recent progress in the synthesis, crystal structures and physical properties of monomeric phthalocyanines (Pcs) is summarized and analysed. The strategies for synthesis and modification of Pcs include axial coordination of central metal ions, peripheral substitution of Pc rings and the ionization of Pcs. The crystal structures of various typical Pcs, especially the effects of different synthetic and modification strategies on the supramolecular assemblies of Pcs via %—% interactions between Pc rings, are discussed in detail. Finally, the UV-vis spectroscopic, conducting, magnetic and catalytic properties of some Pcs with crystal structures are presented briefly, and the correlations between various properties and the molecular structure discussed. 

New Progress in Monomeric Phthalocyanine Chemistry 4.3.2 Magnetic Coupling in Metal-Radical Systems... 

Although several metal-containing heterocyclic compounds (such as porphyrins, phthalocyanines, naphthenates) are present in oil fractions most of the bench-scale research has been based on relatively rapid Ni, V, or Ni/V deposition procedures in which experimental FCC formulations have been artificially metal contaminated with solutions of Ni and/or V naphthenate dissolved in benzene (or toluene) (24). Metal levels in these novel FCC are usually above 0.5% that is well above the concentration that today exist on equilibrium FCC, see Figure 1. High metal concentration facilitate the study and characterization of Ni and V effects by modern characterization techniques such as X-ray photoelectron spectroscopy (XPS), Laser Raman spectroscopy (LRS), X-ray diffraction (XRD), electron microscopy, secondary ion mass spectrometry (SIMS), and 51V nuclear magnetic resonance (NMR). 

In what follows, the first section is devoted to describing transition-metal Pc complex-based ferromagnets and also other related complexes exhibiting no ferromagnetic order. The second section describes the magnetic interaction of n-radical phthalocyanines in crystals. In the last section, we present Pc-based SMMs and a general discussion on magnetism and electronic structure of lanthanide Pc complexes. 

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