Iodosobenzene, organic peracids, and hydroperoxides have been employed with we5o-(tetraphenylporphinato)iron(III) chloride [TPPFemCl] to model the oxidation reactions of cytochrome P-450.1 The products formed when peracids or hydroperoxides are employed with either TPPFemCl or cytochrome P-450 are similar to those obtained in Fenton-type reactions,2'4 whereas

The catalysis of the decomposition of p-cyano-A,A-dimethylaniline A-oxide (NO) with meso-(tetraphenylporphinato)iron(III) chloride [(TPP)FenlCl] has been studied at 25 °C in CH2C12 with [NO],• = 5.0 X 10-4 to 8.0 X 10"3 M > [(TPP)FemCl],• = 3.0 X 10"5 to 5.0 X 10™4 M. The iron(III) porphyrin catalyst was shown to be unaltered in catalytic efficiency to 120 turnovers (the highest examined). The influence of Ó2 and the purity of solvent upon the kinetics of the reactions and products obtained have been assessed. In the absence of an oxidizable substrate, NO gives way to the following products: p-cyano-A,A-dimethylaniline (DA), 52% yield; p-cyano-A-methylaniline (MA), 25% yield; A-formyl-p-cyano-Amethylaniline (FA), 4% yield; p-cyanoaniline (A), 2% yield; A,A-dimethyl-A,A-bis(p-cyanophenyl)hydrazine (H), 12% yield; A,A-bis(p-cyanophenyl)-A-methylmethylenediamine (MD), 6% yield; and CH20,11% yield. The major portion of the products (i.e., DA, MA, H and MD) absorb appreciably at 320 nm where absorbance by (TPP)FemCl is minimal. The formation of products was followed spectrophotometrically at 320 nm and by HPLC at 280 and 320 nm. Both means were found to be in quantitative agreement. Spectral monitoring of the increase in A320 showed that the first-order decomposition of the A-oxide was independent of [NO]( but increases with an increase in [(TPP)FelnCl](. The appearance of DA, MA, FA, MD, and CH20 also followed the first-order rate law, while the formation of the products H and A are characterized by a lag period followed by a constantly accelerated formation ending abruptly with the corisumption of the A-oxide. Of the various products, only A exhibited inhibition of the kinetics for decomposition of A-oxide by (TPP)FemCl. At the concentration formed in the kinetic experiment, however, A is not inhibiting. The rate constant for "oxygen" transfer from NO to (TPP)FemCl to form [(TPP)(Cl)FeIV=0]+• was determined by trapping this species with 2,4,6-tri-zerz-butylphenol (TBPH). In the presence of TBPH trap, DA is formed in 100% yield, showing that the other decomposition products of the A-oxide arise via stepwise oxidation of DA by [(TPP)(Cl)FeIV=0]+•. An intermolecular deuterium kinetic isotope effect of unity was obtained by comparison of the initial rate constants for the reactions of />NCC6H4N+(CH3)207p-NCC6H4N+(CD3)20~. A discriminatory intramolecular deuterium isotope effect of 4.5 was observed when p-NCC6H4N+(CH3)(CD3)0" was used and the formation of p-NCC6H4NH(CD3)/p-NCC6H4NH(CH3) was monitored. The isotope effects are in agreement with the finding that ratedetermining oxygen transfer from NO to (TPP)FemCl is followed by demethylation of DA. A variety of alkenes and cyclohexane are shown to compete with DA as substrates. With these, the yields of epoxidation and/or hydroxylation products are comparable to those reported previously when iodosylbenzene was used as the oxygen source under similar conditions. The stereospecifity seen with iodosylbenzene is also evidenced with NO. At 1.0 M 2,3-dimethyl-2-butene, DA and ...

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The 15N chemical shifts and couplings have been measured for several platinum(II)-amine complexes. The 15N chemical shift changes found on coordination of azine-type nitrogens to platinum appear to be related to those that occur on protonation of the same nitrogens. Both the 15N chemical shifts and the one-bond 15N-195Pt coupling constants depend on the nature of the cis and trans ligands. cis-[Pt(NH3)2Cl2] ("cis-platinum") forms a complex with cytidine through N3. Guanosine becomes bound to platinum of cis-[Pt(NH3)2Cl2] at N7 and at least one other nitrogen. Adenosine appears to bind cis-[Pt(NH3)2Cl2] to at least some degree through N1, N3, N7, and the 6' -NH2.

N -Nitrosodibenzylamine has been oxidised to benzaldehyde and benzyl alcohol by iodosylbenzene, 3c h loroperoxybenzoic acid and tbu tyl h yd roperoxide ca tal ysed by tetrap hen yl porp hyri na toi ron (11 I) chloride or -manganese(iii) chloride. The influence of reaction conditions on the product yields and distribution have been studied. Kinetic isotope effects have been measured with deuteriated N-nitrosodibenzylamines for inter-and intra-molecular competition for the oxidants. The evidence presented is in favour of the iodosylbenzene and t-butyl hydroperoxide oxidations being initiated by hydrogen-atom abstraction by the oxidant from the x-hydrogen of the benzyl group. However, oxidations by the peroxy acid systems may proceed by an initial electron transfer. The reactions of N-nitrosodimethylamine and N-nitrosopiperidine with the metalloporphyrin-catalysed systems show that these substrates are surprisingly unreactive towards oxidation.