Porphyrin and phthalocyanine complexes

The authors are most grateful to Dr. J. G. Jones for his valuable assistance with the preparation of the sections on porphyrin and phthalocyanine complexes. 

Electronic and steric effects in the coordination sphere of porphyrin and phthalocyanine complexes 93KK358. 

Porphyrin and phthalocyanine complexes 48.6-2.8 Miscellaneous nitrogen ligand complexes... 

Square planar geometry is found only in the porphyrin and phthalocyanin complexes. Few examples of 7- and 8-coordination are known (Table 17-D-l). A recent one [MnL](PF6)2, L = the tripodal heptadentate ligand ira 2-[7V-(2-pyridyl-methyl)amino]ethyl, acts as a superoxide scavenger.8 The octahedral acetonitrile complex [Mn(MeCN)6] [Mnl4] with a tetrahedral anion is obtained as yellow crystals from MeCN solutions of Mnl2.9... 

A characteristic feature is the formation of oxo and/or hydroxo bridges.42 Binu-clear systems may be (a) doubly bridged and (b) singly bridged with a linear or bent FeOFe. The bent ones are known with 4-, 5-, and 6-coordinate iron(III) an example is [(salen)Fe]2(/x-0). Porphyrin and phthalocyanine complexes are linear bridged species of the type (porph Fe)2/x-X where X = O, N, and C. 

Relatively few complexes of N-donor ligands are known. One of the best characterized is with the tridentate ligand terpyridyl, which reacts with scandium nitrate to form Sc(terpy )(N03 )s here scandium is connected to 9 atoms, but one Sc-O bond is considerably longer than the others, so a coordination number of 8.5 has been assigned. A range of porphyrin and phthalocyanine complexes exist syntheses often involve the high-temperature routes typical of the transition metals but recently a high-yield low-temperature route has been utilized to make octaethylporphyrin (OEP) complexes ... 

In order to increase the solubility of porphyrin and phthalocyanine complexes, several structural modifications have been made, a, jS, y, 6-Tetra-(4-pyridyl)-porphin complexes of copper(II), nickel(II), and zinc(II) have been synthesized (35) and their ultraviolet spectra determined in chloroform and in acid solution. By utilizing sulfonic acid groups to increase solubility, complexes of 4,4, 4",4" -tetrasulfophthalocyanine complexes of many metals were prepared (94j 95). This chelating agent was found to have a ligand field strength comparable to cyanide (94y 95). 

The macrocycle phthalocyanine contains 8 N atoms, but usually only the four N-atoms on the inner side of the cycle are able to coordinate. In fact, in most cases the synthesis of phthalocyanine is realized in the presence of a metal ion as the template. It is also possible to attach various substituents on the phthalocyanine macrocycle. As for porphyrin, when coordinating to a metal ion, the H-atoms of the two NH groups on the inner side of the phthalocyanine cycle are replaced. The incorporation of metal porphyrin and phthalocyanine complexes into porous crystals has been gaining increasing interest. The properties of the complexes located in zeolite channels or cages are usually different from those of the compounds in solution, and they may find applications in areas such as catalysis, photochemistry, electrochemistry, and biomimetics. 

Porphyrins and phthalocyanins, complexes with metalloids of groups 4A,... 

Pemg YS, Oloman CW, Watson PA, James BR (1994) Catalytic oxygen bleaching of wood pulp with metal porphyrin and phthalocyanine complexes. Tappi J 77 119... 

The rates (A i) indicate pronounced amine lability, in particular piperidine, while the ratio k-i/kg suggest a strong preference for CO binding. Comparison with porphyrin and phthalocyanin complexes indicates that CO dissociation rates are relatively insensitive to the nature of the in-plane ligand unlike, those of amine dissociation k which vary from 1020 s (OMBP) to 0.50 S (phthalocyanine). The binding of CO to [Fe(TAAB)L2] + is very poor in contrast to the above results which may reflect the enormous number of differences in the structure and electronic features of TAAB relative to OMBP and other related chelates. However, CO dissociation does not occur readily, while dimethylglyoxime complexes are even more... 

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