Gallium complexes porphyrins

Gallium alkoxides physical properties, 345 Gallium complexes dimethyl sulfoxide, 488 phthalocyanines, 863 porphyrins, 821 Gallium(III) complexes porphyrins evolution, 961 tropolones rearrangement, 382 Gallium isopropoxides synthesis... 

I and liquid SRC II products and to probe the chemical and structural environment of vanadium in coal and coal liquefaction products.( ) Quantitative aspects of these studies were not considered. In the same vein, an extensive extraction (acidic methanol) and chromatographic procedure has been applied to Daw Mill coal (92 Kg) with the result that 17.8 mg of a mixture of gallium complexes of homologous porphyrins (C27-C32) has been isolated for the first time. Identification was based upon a combination of spectroscopic techniques.( )... 

Porphyrin, octaethyl-, gallium hydroxide complex cyclic voltammetry, 4, 399 <73JA5140)... 

Gallium(III) forms stable (class II, Table 2) porphyrin complexes and has a filled d shell nonetheless, relatively few PDT photosensitizers have made use of complexes of this metal. 

Aluminum, Gallium, Indium, and Thallium Porphyrin Complexes, M(Por)R... 

The thallium complexes show somewhat different electrochemical behavior, and reversible oxidations are observed for both n-alkyl and n-aryl thallium porphyrins, indicating that the oxidized complexes have a more stable metal—carbon bond than the gallium or indium analogs. Spectroelectrochemistry revealed that the first oxidation is porphyrin ring-centered. The first reduction is reversible and ring... 

Overall, the UV-visible, NMR, and electrochemical data for the range of O -bonded complexes of gallium, indium, and thallium porphyrins show that there is a trend from pure a -bonded character of the M—C bond in the alkyl complexes to the much more ionic character observed for the fluorophenyl and acetylide complexes. These more ionic complexes show NMR and UV-visible characteristics more like those of the ionic M(Por)Cl or M(Por)C104 complexes. ... 

Most of the studies on organo-gallium, indium, and thallium porphyrin complexes have focused on synthesis and properties of the complexes, and rather little attention has been devoted to reaction chemistry. Two areas which have received some attention are the insertion of small molecules (SO2 or CO2) into the metal—carbon bonds and photochemical metal—carbon bond cleavage. The... 

Although photochemically induced cleavage of Al—C bonds in the aluminum porphyrin complexes has been exploited in several applications, relatively little is known about the intimate mechanism of this process. Similar reactivity is observed for the organo-gallium and indium porphyrins, and for these elements... 

Scheme 6 Electrochemical reactions of gallium porphyrin complexes...

Corroles are tetrapyrrole macrocycles that are closely related to porphyrins, with one carbon atom less in the outer periphery and one NH proton more in their inner core. They may also be considered as the aromatic version (identical skeleton) of the only partially conjugated corrin, the cobalt-coordinating ligand in Vitamin B12. Two potential application of corroles are in tumor detection and their use in photovoltaic devices. Selective substitution of corroles via nitration, hydroformylation, and chlorosulfonation for the gallium were studied in detail and the respective mechanistic pathways and spectroscopic data were reported, (an example is shown in Figure 27). Overall, over 139 various corroles were synthesized and the effect of various metal complexation pertaining to their selective reactivity examined. 

Other o-bonded metal porphyrins have electronic absorption spectra belonging to the hyperclass. The o-bonded complexes of iron , indium gallium exhibit such typical spectra. Thus, replacement of the anionic axial ligand on the halogenated complexes M(Por)X by an alkyl (or aryl) o-bonded ligand results in a splitting of the Soret band into two bands. One of the bands is red shifted and the other is blue shifted with respect to the same porphyrin complex with anionic axial ligands. This is illustrated in Fig. 2 for In(OEP)Cl and In(OEP)(C(CH3)3). 

The electrochemistry of gallium, indium, and thallium porphyrins with o-bonded aryl and alkyl groups has been reported by Kadish and Guilard . Complexes of Ga(Por)(R), In(Por)(R) and Tl(Por)(R) are reversibly reduced by up to two single electron transfer additions. These electroreductions are shown in Eq. 12 and 13 where M = Ga, In, or Tl. 

Reduction of the gallium and indium complexes involves the porphyrin ir ring system . The site of electron transfer in Tl(Por)(R) is not clear. A reduction of Tl to Tl is possible in Tl(Por)(R) but the similarity in potentials between Ga(Por)(R) and In(Por)(R) suggests that reduction of this complex occurs at the porphyrin n ring system . 

The insertion of sulfur dioxide between the metal atom and the alkyl or aryl group of indium gallium and iron porphyrins of the form M(Por)(R) gives rise to M(Por)S02R sulfinato derivatives (Eq. 18). The iron sulfinato compounds are air stable at room temperature, but can easily be oxidized by a stream of oxygen to give the corresponding sulfonato complexes. 

Electronic spectra of the sulfinato and sulfonato complexes are similar to those of other high-spin iron(III) porphyrins and belong to the hyper class 0. The morphology of the NMR spectra and the chemical shifts of the indium and gallium sulfinato or sulfonato porphyrins are nearly identical to those for the halogenated derivatives ... 

Phosphorus(V) in its most stable oxidation state forms robust chelate complexes with the porphyrin, and retains the capability of binding two oxygen ligands in a frans-axial mode as outlined in Sect. 3. This strategy was used by Maiya [81,102-104] and Tanaka and Segawa [105]. The coordination chemistry of phosphorous(V) porphyrins is similar to germa-nium(IV), tin(IV), gallium(III), and aluminium(III) porphyrin coordination chemistry [102,106]. These metalloporphyrins were shown to form multiporphyrin complexes with phenol-substituted porphyrins. Because of the... 

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