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Octaethylporphyrmato)rhodium(III) chloride, (OEP)RhmCl, reacts with benzene in the presence of AgC104 or AgBF4 to give the phenyl-rhodium(III) complex. Anisóle, toluene, and chlorobenzene are similarly metalated exclusively at the para positions. The metalation of methyl benzoate, on the other hand, gives a 92:8 mixture of meta-and para-metalated isomers. The reactivities of arenes follow the Hammett equation with the p value of -5.43. The observed substituent effects both on reactivity and orientation unambiguously characterize the present reaction as an electrophilic aromatic metalation with a [(OEP)Rhm]+ intermediate generated from the anion exchange of (OEP)RhnlCl with silver salts. The slow step in the reaction is coordination of arene to form [(OEP)Rh(arene) ]+, which subsequently loses a proton. Arenes thus activated with rhodium undergo photochemical homolysis of the C-Rh bond as well as its halogen-induced heterolysis.

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Measurements obtained with nonenhanced MR angiography appear equally accurate to those of CT angiography in the preoperative planning of abdominal EVAR.