Ruthenium(II) complexes with phosphonate-substituted phenanthroline ligands: synthesis, characterization and use in organic photocatalysis.

Ru(II) complexes with polypyridyl ligands play a central role in the development of photocatalytic organic reactions. This work is aimed at the structural modification of such complexes to increase their photocatalytic efficiency and adapt them for the preparation of reusable photocatalytic systems. Nine [Ru(phen)(bpy)2]2+-type complexes (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline) (Ru-Pcat) bearing the P(O)(OEt)2 substituent attached to the phen core directly or through a 1,4-phenylene linker were synthesized and characterized by spectroscopic and electrochemical techniques. The coordination mode of phen ligands was confirmed by single crystal X-ray analysis. The (spectro)electrochemical data show that the first electron transfer in Ru-Pcat takes place on the phen ligand. The emission maxima and quantum yields are strongly affected by the substitution pattern, reaching the far-red region (697 nm) for Ru-3,8P2. The singlet oxygen quantum yields of Ru-Pcat were evaluated using the chemical trapping method. Finally, the photocatalytic performance of Ru-Pcat in the oxidation of sulfides with molecular oxygen was investigated. Both dialkyl and alkyl aryl sulfides were quantitatively transformed into sulfoxides under irradiation with a blue LED in the acetonitrile-water mixture (10 : 1) using a low loading of 0.005-0.05 mol% Ru(II) photocatalysts. To rationalize the effect of phosphonate substituents on the photocatalytic efficiency, comparative kinetic studies of (1) 4-nitrothioanisole oxidation proceeding predominantly via the electron transfer pathway and (2) oxidation of dibutyl sulfide wherein singlet oxygen serves as an oxidant have been performed. It was demonstrated that complexes with the P(O)(OEt)2 substituent at positions 4 and 7 outperform the benchmark photocatalyst Ru-(bpy)3 and the parent complex Ru-phen in the reactions proceeding through electron transfer (reductive quenching photocatalytic cycle). The TON in the oxidation of 4-methoxythioanisole was found to be as high as 1 000 000 that is, to our knowledge, the highest among previously reported photocatalysts. In contrast, upon separating the P(O)(OEt)2 group and the phen core with the 1,4-phenylene linker, singlet oxygen quantum yields significantly increase that favors reactions proceeding through energy transfer (the oxidation of dibutyl sulfide in our case). Thus, both series of Ru(II) complexes prepared in this work are promising for the improvement of known photocatalytic reactions and the development of new transformations.

Disease expression in women with hereditary angioedema.

OBJECTIVE: Fluctuations in sex hormones can trigger angioedema attacks in women with hereditary angioedema. Combined oral contraceptive therapies, as well as pregnancy, can induce severe attacks. The course of angioedema may be very variable in different women. STUDY DESIGN: Within the PREHAEAT project launched by the European Union, data on 150 postpubertal women with hereditary angioedema were collected in 8 countries, using a patient-based questionnaire. RESULTS: Puberty worsened the disease for 62%. Combined oral contraceptives worsened the disease for 79%, whereas progestogen-only pills improved it for 64%. During pregnancies, 38% of women had more attacks, but 30% had fewer attacks. Vaginal delivery was usually uncomplicated. Attacks occurred within 48 hours in only 6% of cases. Those more severely affected during menses had more symptoms during pregnancies, suggesting a hormone-sensitive phenotype for some patients. CONCLUSION: The course of angioedema in women with C1 inhibitor deficiency is affected by physiologic hormonal changes; consequently, physicians should take these into account when advising on management.

Redox-active biomolecular architectures and self-assembled monolayers based on a cyclodecapeptide regioselectively addressable functional template.

A nanometer scale redox active biomolecular architecture has been successfully synthesized through an efficient chemoselective oxime based coupling between ferrocenyl groups and a regioselectively addressable cyclodecapeptide. This molecular tool exhibits electronic, structural, and chemical properties driven by the biomimetic recognition activity of the polypeptide skeleton associated to the well-defined electrochemical activity of metallocenyl probes. Biomolecular materials obtained by confinement of the redox cyclopeptide in self-assembled monolayers on gold surfaces shows efficient through-bond electron transfer from the ferrocenes to the electrode surface via the peptidic backbone, as well as markedly improved sensing properties toward anionic species in organic electrolyte, as compared to those observed in homogeneous solution.