Novel metalloporphyrins. Syntheses and implications

Abstract

The last few years have seen substantial growth in metalloporphyrin research. Certainly most of this stems from interest in the biological systems to which these compounds are related. However metalloporphyrins are also studied for other reasons. These include the search for new semiconductors,1 superconductors,2 anticancer drugs,3 and catalysts.4Several porphyrin-related compounds, particularly the phthalocyanines,5 have proved useful as dyes.Even without their biological and industrial implications the properties of metalloporphyrins would be studied for their purely theoretical importance. Thus, even to the nonspecialist, a knowledge of the more recent or unusual synthetic metalloporphyrins could be useful.The porphyrins are compounds formed by adding substituents to the nucleus of porphine (1). The nat-R5 Rh r4 1 urally occurring porphyrins are generally formed by adding substituents to positions 1-8 and are named according to the number and type of substituents. The roman numerals after the name indicate the pattern of substitution. Of the large number of possible arrangements, few have been found in nature. Table I lists several porphyrins, both natural and synthetic, along with their trivial names. Certain common porphyrins will hereafter be referred to by abbreviations listed in Table I.Upon removal of the pyrrole protons, porphyrins readily complex with a variety of metals. While free David Ostfeld was born in Chicago in 1942. He earned his B.S. in Chemistry from the University of Illinois and his Ph.D. from Cornell Uniersity. Three years of postdoctoral work, including a year with Professor Tsutsui, were devoted to studying metalloporphyrin chemistry. Currently he is

Insertion of Ni(I) into Porphyrins at Room Temperature: Preparation of Ni(II)porphyrins, and Ni(II)chlorins and Observation of Hydroporphyrin Intermediates

“…We chose Ni­(COD) 2 as a readily available Ni(0) complex, and three electronically different porphyrins to investigate the scope of the approach: 5,10,15,20-tetrakis­(4-methoxyphenyl)­porphyrin (TPPOMe) 1a , as an example for an electron rich porphyrin, the parent 5,15,10,20-tetraphenylporphyrin (TPP) 1b , and 5,10,15,20-tetrakis­(pentafluorophenyl)­porphyrin (TPPF 20 ) 1c , which is a typical example of an electron deficient porphyrin. Transition metal carbonyl complexes have been used before to insert metals into porphyrins, , however, in our hands Ni­(CO) 4 did not react with 1c . Upon simple mixing of the free base porphyrin with a two- to 4-fold excess of Ni­(COD) 2 in toluene at room temperature under a nitrogen atmosphere, the color immediately changes from red to green and after stirring for 1–2 h the corresponding Ni-porphyrins and the Ni-chlorins are isolated ( 1 H NMR and UV–vis spectra see Figure ).…”

Eggshell spotting does not predict male incubation but marks thinner areas of a shorebird's shells

“…Protoporphyrin (a cyclic tetrapyrrole) is an immediate precursor of the heme molecule, whereas biliverdin (a linear tetrapyrrole) is a product of hemoglobin breakdown. Protoporphyrin and biliverdin pigments can bind ions of trace metals, primarily iron (Fe) or zinc (Zn), but almost all other metals can be incorporated into their molecules (Ostfeld and Tsutsui 1974, Mikšík et al 1996, Casini et al 2003, Williams et al 2016. Protoporphyrin and biliverdin occur at varying levels in the shells of most birds' eggs, irrespective of their coloration (Mikšík et al 1996, Cassey et al 2011, Wang et al 2011, Brulez et al 2016, and their distribution varies between the speckled and plain areas of the shells .…”

Unusual Metalloporphyrin Complexes of Rhenium and Technetium

“…8 Except for lanthanides 24 aPA actinides, almost every metal in the periodic table has been coordinated tý porphyrin. 7 Any reasonable porphyrin complex desired by inorganic chemi;rý :,!ems attainable through the powerful synthetic methods which are now available. These methods included:…”

“…This method has been found quite general for metals having suitable derivatives and developed to an useful end unique method in the syntheses of unusual metalloporphyrins within the last decade. 7 In addition to a number of previously reported metalloporphyrins, the reaction of metal carbonylsor metal carbonyl halides with neutral porphyrins has led to the syntheses of new metalloporphyrin complexes of chrom2um25*36, molybdenum36,37, ruthenium28'38 , rhodium 3 The characterization of these compounds was done by elemental analyses, visible, Infrareds proton magnetic resonance, and mass spectra (Tables 1 and 2).…”

“…7 1 Scattering factors were from the International Tables. 7 2 The metal ions were assumed to be in the zero Ionization state.…”