Isomeric And Expanded Porphyrins

Author : Saovalak Sripothongnak
Publisher :
ISBN 13 :
Total Pages : 226 pages
Book Rating : 4.:/5 (794 download)

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Download or read book The Metal Binding Chemistry of the Carbahemiporphyrazines written by Saovalak Sripothongnak and published by . This book was released on 2010 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Porphyrin is an aromatic naturally occurring molecule that has important roles in biological systems such as light harvesting, electron transfer and oxygen transport. In addition, porphyrin has unusual coordination and electronic properties leading to many applications including as catalysts, advanced materials and photodynamic therapy agents. Because of these roles, porphyrins are some of the more studied fields in chemistry. In order to understand the role of the porphyrin macrocycle in its coordination and electronic properties, chemists have modified the structure of porphyrin either in skeletal or peripheral positions. As the result, porphyrin analogs and isomers of porphyrin, including contracted porphyrins, expanded porphyrins and heteroatom substituted porphyrins, have been synthesized. Azaporphyrins are porphyrin derivatives that are generated by the replacing of one or more meso sp2 hybridized carbon atoms with nitrogen atoms. These macrocycles exhibit unique coordination and electronic properties. The phthalocyanines are the best known azaprophyrins. Phthalocyanine was first prepared by Braun and Tcherniac in 1907. Phthalocyanine is well-known in the dye and pigment industry. There has been much research and development into molecules related to phthalocyanine. One such example is hemipoprhyrazine[sic]. Hemiporphyrazines are members of the phthalocyanine family that have been studied for over five decades. Hemiporphyazines have extremely different chemical and physical properties from phtalocyanine even though hemiporphyrazine is generated by replacing two isoindoline rings of phthalocyanine with alternate rings, such as pyridines. The hemiporphyrazine derivatives dicarbahemiporphyrazine and benziphthalocyanine were first synthesized in the 1950s by Linstead and Elvidge. Benziphthalocyanine and dicarbahemiporphyrazine are generated by replace one and two isoindoline unit of phthalocyanine with benzene ring, respectively. The presence of carbon atoms in the core of these macrocycles results in unusual coordination and electronic properties. Prior to 2006, the metallation of these adducts was not explored even though the free bases of dicarbahemiporphyrazine and benziphthalocyanine were prepared about 50 years earlier. This dissertation will describe the metal chemistry, including coordination, electronic and physical properties of several metal complexes of dicarbahemiporphyrazine and benziphthalocyanine including lithium and nickel. N-Confused porphyrin is a well studied porphyrin isomer. The structure of this ring is the same as normal porphyrin but with one pyrrole inverted such that there are three nitrogen atoms at the core and one nitrogen atom at the periphery of the macrocycle. Over the past fifteen years, a variety of metal complexes of N-confused porphyrin have been prepared, including iron, cobalt, manganese, nickel, copper and zinc. This dissertation will present the synthesis and the metal binding chemistry of the first lithium and chromium complexes of N-confused porphyrin."--Abstract.