Colorful Friedel-Crafts chemistry of meso-tetraarylporphyrins. An unexpected route to porphyrinic spiro dimers

Under Friedel-Crafts conditions, meso-tetraarylporphyrins give porphyrin spiro dimers in good yield. This reaction involves acylation, acid-catalyzed cyclization, and dimerization. A stable dimer possessing three additional six-membered rings could be isolated and its structure determined. By modifying the substrate and reagents, intermediates could be isolated and characterized. The reactivity of the substrates, the side-reactions, and the concentration requirements to form the dimers, all explain why this reaction remained apparently unexplored in the widely used meso-tetraarylporphyrin series. [reaction: see text]     

Direct photon production from pions and protons at 200 GeV/c

Direct photon production has been studied by an experiment performed with the NA3 spectrometer at CERN, using incident negative and positive beams at 200 GeV/c interacting with an isoscalar Carbon target. Two different triggers have been used; one of them requires the photon conversion. The experiment is sensitive to direct photons produced with 3.0≦P _T ≦6 GeV/c and center-of-mass rapidity ?0.4≦y ^*≦1.2. Inclusive cross sections are given for incident π^± and protons, and compared with second order QCD predictions; finally an estimation of the gluon structure function of the nucleon is given.     

紫外光照射下 Fe-碳纳米管/TiO2 复合材料降解罗丹明 B

 The composites comprising Fe-carbon nanotubes (CNTs) on TiO2 were prepared by a modified sol-gel method and characterized by nitrogen adsorption, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and energy dispersive X-ray analysis. The photocatalytic decomposition of rhodamine B (Rh.B) under UV irradiation and air aeration catalyzed by the composites was measured. The photocatalytic activity of TiO2 nanoparticles was significantly enhanced by the large CNT network that facilitated electron transfer between adsorbed Rh.B molecules and the catalyst substrate and the simultaneous occurrence of the photo-Fenton reaction in the presence of Fe particles. A marked acceleration of the decomposition rate was observed with aeration by flowing air aeration due to the formation of the circulatory photo-Fenton system. Chemical oxygen demand of piggery waste was measured at regular intervals to evaluate the mineralization of wastewater.     

Angular distributions in the dimuon hadronic production at 150 GeV/c

From π^- interactions at 150 GeV/c on a heavy target, we present the final analysis of the dimuon decay angular distribution in the mass interval 4.5–8.5 GeV/c². Results are presented and discussed in various reference frames and are also given in terms of the density matrix elements. Finally the possible contribution of higher-twist effects at largex ₁ is discussed; we find that our data are not compatible with higher twist contributions as proposed by the Berger and Brodsky Model.     

Oxidative cyclization of substituted N-vinylporphyrin cobalt complexes. Synthesis of N,N′-(1,2-vinylidene) and N,N′-(1,2-phenylene)porphyrins.

The oxidative cyclization of substituted N-vinylporphyrin cobalt complexes gave N,N′-1,2-vinylidene porphyrins. In the case of a cyclic fragment further dehydrogenation gave a product similar to the 1,2-phenylene bridged porphyrin obtained on inactivation of cytochrome P-450 by 1-aminobenzotriazole.     

Homologation of n-alkanes using diazoesters and rhodium(III)porphyrins. Enhanced attack on primary CH bonds.

Carbethoxycarbene, from ethyl diazocetate and rhodium(III)porphyrins, inserted into methyl CH bonds of n-alkanes (C₆ to C₁₂) with yields up to 20–25% corresponding to a large increase of the primary/secondary selectivity.     

Model for the in vivo transformation of cytochrome P-450 into “green pigments”

Alkyl transfer from the metal to a pyrrolic nitrogen of a metalloporphyrin is described as a model of heme modification during abnormal metabolism of drugs.     

Synthesis of n-aminoporphyrins

Amination of octaethylporphyrin and meso-tetraphenylporphyrin using O-mesitylsulfonylhydroxylamine leads to N-aminooctaethylporphyrin and N-amino-meso-tetraphenylchlorin respectively.