Indium porphyrins

Fig. 25. Structure of water-soluble indium porphyrins with rele vance to inIn SPECT.

The anion optical sensor can also be fabricated with metalloporphyr-ins. For example, polymeric membranes doped with indium porphyrins and a lipophilic dichlorofluorescein derivative were shown to be very selective to chloride and acetate anions. The response mechanism is based on extraction of anions into the bulk organic film by indium porphyrins and a simultaneous coextraction of hydrogen ions. This results in protonation of the pH chromophore, and hence a change in the optical absorbance of the polymeric film. 

E. Wang, C. Romero, D. Santiago and V. Syntilas, Optical anion sensing characteristics of indium-porphyrin and lipophilic dichlorofluorescein doped polymer films, Anal. Chim. Acta, 433 (2001) 89-95. 

Tetraphenylporphyrin indium hydride (TPP)InH reacts with H2Os3(CO)10(NC5H5) in hot toluene to afford the cluster-bound indium-porphyrin complex H2Os3(CO)9(NC5H4)In(TPP), 56.86... 

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... 

The one-electron oxidation of hydroxy(tetramesitylporphyrinato)iron(III) in CH2C12 is reversible on the cyclic voltametric timescale and its spectrum, obtained by double potential step chrono-absorptometry, indicates ring-based oxidation. However, at longer times, loss of hydroxide ion occurs, followed by reduction of the dication in an ECE process.61 Loss of axial ligand also was shown to occur for indium porphyrin during both oxidation and reduction.62... 

The nature of the porphyrin ring may influence reactions which are photoactivated or sensitized by visible light. Although electron transfer from metalloporphyrins to other substrates has been widely studied, examples for activation of the ligand bound to the metal upon irradiation have been very limited. The reactivity of o-bonded aluminum and indium porphyrins towards carbon dioxide has been studied. 

Similar photochemical insertion reactions are observed for indium alkylporphy-rins In the presence of pyridine and under irradiation by visible light, carbon dioxide inserts into the carbon-indium o bond leading to stable carboxylate indium porphyrins (Scheme 10). 

The insertion reaction of sulfur dioxide is of interest since it could lead to metal sulfinates which possess potential catalytic, bacterial, and plant growth regulator activities This reaction is known for iron, gallium, and indium porphyrins ... 

Sulfinato and sulfonato indium porphyrins are also isolated by oxydation of the corresponding thio In(Por)(SR) derivatives (Eq. 19). 

Various metal-metal single o-bonded complexes have been obtained by the reaction of metal carbonyls with metal-carbon o-bonded porphyrins or by the reaction of metal carbonyl anions and chlorometalloporphyrins (Scheme 14). For example, the reaction of dimanganese carbonyl and methyl indium(III) porphyrin gives manganese pen-tacarbonyl indium porphyrin In(Por)Mn(CO)5. The same compound is isolated when chloroindium porphyrin is allowed to react with the manganese pentacarbonyl monoanion. Various iron, cobalt, tungsten, and molybdenum complexes have been prepared by these two methods. 

Zheng and coworkers have employed a similar methodology and have demonstrated that PVC membranes doped with indium tetraphenylporphyrin show high relative sensitivity to nitrite ions.- Manganese and indium porphyrins immobilized in silicone by Paeng et al. have been used for the potentiometric analysis of serum chloride levels." ... 

Reaction of the porphyrin indium hydride species In(TPP)H (TPP = 5,10,15,20-tetraphenylporphirinato) with H(/i-H)Os3(GO)io(GsH5N) under anaerobic conditions affords the In-Os bonded cluster-porphyrin compound (TPP)In-Os3(/x-H)2(GO)9(/x-77 -G5H4N) 1. The indium porphyrin moiety occupies an equatorial position on the OS3 ring, and is bound to the single Os atom that is not bridged by an A-heterocyclic ring. The indium porphyrin moiety is looked upon as a one-electron donor. ... 

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

Porphyrin, tetrahydro-metal complexes geochemistry. 6, 862 Porphyrin, tetraphenyl-indium complexes radiopharmacology, 6, 971 iron complexes, 4, 260,1266 zinc complexes spectra, 6, 617... 

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... 

The CO2 activation reactions seen for aluminum porphyrins are also observed for In(Por)Me (Por = OEP, TPP), which will insert CO2 in the presence of pyridine and under irradiation by visible light to give the acetato complex In(Por)OC(0)Me. The indium acetato product has been characterized by X-ray crystallography, whereas in the aluminum complex it was observed only by spectroscopy. An alternative synthesis of the acetato complex is by treatment of ln(Por)Cl by alumina and water, followed by acetic acid. For the indium and... 

Ge(TPP)R2, Ge(TPP)(Fc)Ph, and Ge(TPP)Fc2) the spectrum after 2 /us was consistent with a triplet excited state, although this decayed much faster for the fer-rocenyl complexes. Addition of ferrocene to Ge(TPP)R2 also quenches triplet lifetimes. A similar situation was observed for the indium complexes In(Por)R, and the triplet-state quenching was attributed to an energy transfer process from the excited-state triplet to ferrocene. In the case of the germanium porphyrins, the longer-lived triplet state in Ge(TPP)R2 is responsible for the Ge—C bond homolysis, and both inter- and intramolecular quenching by ferrocene is observed. 

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