Fuel cell reactions invariably involve an oxygen reduction reaction (ORR) at the cathode, which is one of the main rate-decreasing steps on platinum (Pt)-catalysts in the water formation reaction and energy conversion efficiency in polymer electrolyte membrane fuel cells (PEMFCs). The Pt scarcity and cost have led to the development of alternative catalyst materials for fuel cell applications. This paper reviews ORR catalysts with regard to their classification, mechanism, activity and performances. From conventional Pt-based catalysts to non-noble metal or bio-inspired catalysts, we show how significant progresses were made in ORR catalysis.

Low-platinum and platinum-free catalysts for the oxygen reduction reaction at fuel cell cathodes

Supramolecular chemistry, defined as “chemistry outside a molecule”, is at the heart of the development of chemistry of complex systems, molecular devices, ensembles, and nanochemistry.1 This is the chemistry where molecules are able to self-organize, self-assemble, and self-control into systems and the components are often analogues to biological molecules. Metalloporphyrins and metallophthalocyanines are remarkable precursors in supramolecular chemistry, and the rapid development of this chemistry led to assemblies possessing various architectures and properties (photo-, electro-, and catalytic properties and others). Metalloporphyrins are one of the cornerstones on which the existence of life is based, and major biochemical, enzymatic, and photochemical functions depend on the special properties of a tetrapyrrolic macrocycle. However, metalloporphyrins are the only molecules as key elements that require assembly with other elements to form the supramolecular structure, that is, the working device. In natural systems, polypeptides define a given structural organization and hold all the moieties together. Such complex natural devices are not accessible by direct chemical synthesis so far, but their modeling, using simplified designs, has been actively exploited during the last decades. The rapid development of this new area of chemistry has promoted the understanding of the concepts of design and strategies of self-assembly of structures based on intermolecular interactions to result in natural and synthetic supramolecular complexes of metalloporphyrins. Synthetic metalloporphyrin complexes are often used as analogues of natural systems found in photosynthesis, oxygen carriers, and catalysts.2,3 Such research also led to the discovery of new applications of these systems, for example in photodynamic therapy, information storage devices or photoelectrical devices that transform energy in both directions (photocells and lightemitting diodes).4-6 An application of increasing importance is the use of metalloporphyrins as receptors, exploiting their ability to selectively form complexes which can sharply change the spectral properties.7,8 Using molecules that combine different receptor units such as porphyrins and † A.N. Frumkin Institute of Physical Chemistry and Electrochemistry. ‡ Université de Bourgogne. Irina Beletskaya was born in 1933 in Leningrad (USSR). She received her Diploma in 1955, her Ph.D. in 1958, and her Doctor of Chemistry degree in 1963, all at M.V. Lomonosov Moscow State University. The subject for the latter was “Electrophilic Substitution at Saturated Carbon”. She became a Full Professor in 1970. She is currently a head of the Laboratory of Organoelement Compounds at M.V. Lomonosov Moscow State University and a full member (Academician) of Russian Academy of Sciences. She was a recipient of the Lomonosov Prize (1979), the Mendeleev Prize (1982), and the Nesmeyanov Prize (1991). Irina Beletskaya is a chief editor of the Russian Journal of Organic Chemistry. She is the author of more than 1000 articles and a number of monographs. Her current scientific interests are focused on organoelement compounds, transition metal catalysis, and organocatalysis. Chem. Rev. 2009, 109, 1659–1713 1659

Supramolecular chemistry of metalloporphyrins.

The control of luminous radiation has extremely important implications for modern and future technologies as well as in medicine. In this Review, we detail chemical structures and their relevant photophysical features for various groups of materials, including organic dyes such as metalloporphyrins and metallophthalocyanines (and derivatives), other common organic materials, mixed metal complexes and clusters, fullerenes, dendrimeric nanocomposites, polymeric materials (organic and/or inorganic), inorganic semiconductors, and other nanoscopic materials, utilized or potentially useful for the realization of devices able to filter in a smart way an external radiation. The concept of smart is referred to the characteristic of those materials that are capable to filter the radiation in a dynamic way without the need of an ancillary system for the activation of the required transmission change. In particular, this Review gives emphasis to the nonlinear optical properties of photoactive materials for the functi...

Nonlinear Optical Materials for the Smart Filtering of Optical Radiation.

7.1. Synthesis 306 7.2. Spectroscopic and Redox Properties 307 7.2.1. Optical Spectroscopy 307 7.2.2. Redox Properties 310 7.2.3. Other Characterization Methods 312 8. seco-Porphyrazines 312 8.1. Synthesis 312 8.2. Spectroscopic and Redox Properties 312 8.2.1. Optical Spectroscopy 312 8.2.2. Redox Properties 313 8.2.3. Other Characterization Methods 313 9. Conclusions 313 10. Abbreviations 314 11. Acknowledgments 314 12. References 314

Low Symmetry Phthalocyanines and Their Analogues

Synthetic pathways to water-soluble phthalocyanines and close analogs

Synthesis, characterization and some properties of novel bis (pentafluorophenyl )methoxyl substituted metal free and metallophthalocyanines

Synthesis, characterization and electrochemistry of novel differently octasubstituted phthalocyanines

Synthesis and characterization of novel 4-nitro-2-(octyloxy)phenoxy substituted symmetrical and unsymmetrical Zn(II), Co(II) and Lu(III) phthalocyanines

The following substituted amino and diaminoglyoximes have been synthesized: N-(phenyl)aminoglyoxime, N-(1-naphthyl)aminoglyoxime, N-(2-naphtyl)aminoglyoxime, 1,1′-biphenyl-4-amino-4′-aminoglyoxime, 1,1′-biphenyl-4,4′-bis(aminoglyoxime), N, N′-bis(1-naphthy1)diaminoglyoxime, N, N′-bis(2-naphthyl)diaminoglyoxime. Their complexes with Cu(II), Ni(II), Co(II), Zn(II), Cd(II) and UO2(VI) have been isolated. The structures of these new compounds are proposed on the basis of elemental analysis, n.m.r., i.r., u.v.-visible spectral data.

The Synthesis and Complex Formation of Swe New Substituted Amino and Diaminoglyoximes

A new sandwich-tpype dilutetium tetraphthalocyanine 4 has been synthesized by the reaction of dimeric lutetium(III) phthalocyanine 3 with two equiv. of dilithium octakishexylthiophthalocyanine in amyl alcohol. Compound 3 was prepared from 4′,5′,4″,5″-tetraiminoisoindoline(1,4,7,10-tetrathia-12-crown-4) 1, 4,5-bis(hexylthio)-1,2-diiminoisoindoline 2 and lutetium acetate in amyl alcohol. Compounds 3 and 4 were characterized by elemental analysis, UV/visible, IR, 1H NMR and ESR spectroscopy. The electrochemical and electrochromic properties of 3 and 4 have been examined by cyclic voltammetry. Both 3 and 4 displayed well-defined electrochromic behavior.

Özer Bekaroğlu

Papers

Synthesis, characterization and some properties of novel bis (pentafluorophenyl )methoxyl substituted metal free and metallophthalocyanines

Synthesis, characterization and electrochemistry of novel differently octasubstituted phthalocyanines

Synthesis and characterization of novel 4-nitro-2-(octyloxy)phenoxy substituted symmetrical and unsymmetrical Zn(II), Co(II) and Lu(III) phthalocyanines

The Synthesis and Complex Formation of Swe New Substituted Amino and Diaminoglyoximes

Synthesis, characterization, and electrochemical and electrochromic properties of sandwich dilutetium tetraphthalocyanine.