Porphyrins electrochemical synthesis

Several types of porphyrin and phthalocyanine ligand modification have been performed to create a new family of electrochemically polymerizable complexes. The most commonly used porphyrins are the amino " hydroxy methoxy ° ° , vinyl- and other " substituted macrocyclic complexes (see examples in Figure 8.13). In the case of phthalocyanine, tetra-amino-substituted macrocycle was exclusively and intensively developed. Studies of these complexes have focused on the electrochemical synthesis and characterization of conductive polymeric or copolymeric materials. 

Malinski s group showed in early 1990s pioneering works on the electrochemical synthesis and characterization of conductive porphyrinic polymeric and... 

The optical and electrochemical properties of porphyrins make these chromophores useful building blocks for the synthesis of electro- and photoactive polymers. Two types of linear polymers have been constructed using the self-assembly approach homo-polymeric assemblies and hetero- or shish kebab polymers. 

The electrosynthesis of metalloporphyrins which contain a metal-carbon a-bond is reviewed in this paper. The electron transfer mechanisms of a-bonded rhodium, cobalt, germanium, and silicon porphyrin complexes were also determined on the basis of voltammetric measurements and controlled-potential electrooxidation/reduction. The four described electrochemical systems demonstrate the versatility and selectivity of electrochemical methods for the synthesis and characterization of metal-carbon o-bonded metalloporphyrins. The reactions between rhodium and cobalt metalloporphyrins and the commonly used CH2CI2 is also discussed. 

The synthesis of metalloporphyrins which contain a metal-carbon a-bond can be accomplished by a number of different methods(l,2). One common synthetic method involves reaction of a Grignardreagent or alkyl(aryl) lithium with (P)MX or (PMX)2 where P is the dianion of a porphyrin macrocycle and X is a halide or pseudohalide. Another common synthetic technique involves reaction of a chemically or electrochemically generated low valent metalloporphyrin with an alkyl or aryl halide. This latter technique is similar to methods described in this paper for electrosynthesis of cobalt and rhodium a-bonded complexes. However, the prevailing mechanisms and the chemical reactions... 

The second article deals with the synthesis and properties of metal correlates and corrinoids. In view of the many articles written on corrinoids, the correlates are in the foreground of the article, adetailed discussion oftheir structures, of their IR-, UV/Vis-, photoelectron-, and NMR spectra, and of their electrochemical behavior being given. Sylvia Licoccia is Professor of Chemistry at the University of Rome Tor Vergata and has not only made notable scientific contributions to corrole chemistry, butto porphyrin chemistry as well. 

Electrochemical reduction of Ni(taab)2+ [taab = (20), see p. 231] occurs in two one-electron steps, to complexes formulated as [Nim(taab)] + and [Niu(taab)]°. The relationship between the annulene taab and the two-electron reduction product, the porphyrin-like taab2-, is discussed.102 The preparation of macrocycles of type (87) by a template synthesis requires a minimum ring size of x = y = 3 and depends upon the strong complexing of the metal ion at the pH of the reaction, otherwise the metal hydroxide precipitates. The NiL(C104)2,nH20 (n = 0, 1, or 2) species have been prepared for x = 3, y = 4.479... 

Matemadombo F, Maree MD, Ozoemena K I, Westbroek P, Nyokong T (2005) Synthesis, electrochemical and spectroelectrochemical studies of octa phenyl thio-substituted phthalocyanines. J Porphyrins Phthalocyanines 9(7) 484-490... 

Obirai J, Rodrigues Pereira N, Bedioui F, Nyokong T (2003) Synthesis, spectral and electrochemical properties of a new family of pyrrole substituted cobalt, iron, manganese, nickel and zinc phthalocyanine complexes. J Porphyrins Phthalocyanines 7(7) 508-520... 

Jiang Z, Ou Z, Chen N, Wang J, Huang J, Shao J, Kadish KM (2005) Synthesis, spectral and electrochemical characterization of non-aggregating a-substituted vanadium(IV)-oxo phthalocyanines J Porphyrins Phthalocyanines 9(5) 352-360... 

A library of 83 metalloporphyrins was generated by parallel synthesis.75 The substitution pattern was varied at the meso position of the porphyrines, and the central metal ions were altered (Table 14.3). To investigate the use of the members of the library as electrocatalytic material for sensitive sensors for nitric oxide (NO), a complex assay sequence was fulfilled by means of the electrochemical robotic system (Fig. 14.24). In first step, residual water was removed... 

Among all the single Co porphyrins examined, a [3-pyrrole substituted species bearing two ester groups, mentioned briefly in Section 3.1.2, (see insert, Figure 3.51) was found to display a rather unique behavior upon adsorption on carbon surfaces. This macrocycle, to be denoted as CoPI, is a precursor to the synthesis of the first face-to-face porphyrin examined in an electrochemical environment [95] hence, a discussion of its properties serves to underscore the effects associated with changes in the electrocatalytic microenvironment following covalent dimerization (see below). 

Guilard R, Francois J, Gros CP, Barbe JM, Ou Z, Shao J, Kadish KM (2001) Synthesis of an anthracenyl bridged porphyrin-corrole bismacrocycle physicochemical and electrochemical characterisation [sic] of the biscobalt p-superoxo derivative. C R Acad Sci Paris Chimie 4 245-254... 

The synthesis of diiron(lll) Pacman porphyrin constructs can be prepared in a manner similar to that shown in Schemes 2 and 3. Initial synthetic targets were centered on diiron(lll) hydroxide bisporphyrin Pacman systems for applications involving electrochemical or photochemical water oxidation via a scheme that is the reverse of those implicated for O2 reduction by dicobalt(II) bisporphyrin... 

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