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Aza[n]helicene phosphole derivatives have been prepared from aza[n]helicene diynes by the Fagan–Nugent route. Their photophysical properties (UV/Vis absorption and emission behavior) have been evaluated. Their behavior as P,N chelates towards coordination to PdIIand CuIhas been investigated: metal–bis(aza[n]helicene phosphole) assemblies are formed by a highly stereoselective coordination process, as demonstrated by X‐ray crystallography. An aza[6]helicene phosphole bearing an enantiopure helicene part has been obtained, which allows the preparation of enantiopure PdIIand CuIcomplexes with original topologies and high molar rotation (MR) and circular dichroism (CD). The structure–property relationship established from the experimental data has been studied in detail by theoretical studies (TDDFT calculations of UV/Vis, CD, and MR). Aza[n]helicene phosphole derivatives show π conjugation extended over the entire molecule, and its influence on the MR of aza[6]helicene phosphole 5 chas been demonstrated. Finally, it has been shown that the nature of the metal (coordination geometry and electronic interaction) can have a great impact on the amplitude of the chiroptical properties in metal–bis(aza[n]helicene phosphole) assemblies.

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The synthesis of optically pure 2pyridylphospholene ligands by diastereomeric resolution of PdIIcomplexes, bearing the corresponding racemic P,N ligand and Rαmethylbenzylamine, by means of fractional crystallisation is described. A full coordination study of palladium complexes containing 2pyridylphospholene and the corresponding phosphole ligands, both in solution by means of NMR spectroscopy and in the solid state by Xray diffraction, was carried out. These ligands were evaluated in Pdcatalysed allylic substitution of racemic substrates rac3acetoxy1,3diphenyl1propene and rac3acetoxy1cyclohexene and E3acetoxy1phenyl1propene. A modelling study of the palladium allylic intermediates was performed in order to justify the asymmetric induction observed with the 2pyridylphospholene ligands.© WileyVCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009

PS, I love you!Novel mixed phosphole/thiophene π‐conjugated systems were synthesized and their electronic properties have been studied both experimentally by UV/Vis spectroscopy and electrochemistry and by theoretical calculations. Exploiting the chemistry of both P‐ and S‐heteroles allows the generation of a diverse range of novel ring‐fused benzophosphole–thiophene derivatives.

Bridging ligandsin AgIand AuIbimetallic complexes: The P moiety of bis(2‐pyridyl)phosphole acts as a symmetrically, semi‐, or non‐bridging donor in AgIdimers (see figure). In related AuIcomplexes, only the non‐bridging mode is observed. An unsaturated AgIdimer is used as an adaptive molecular clip for the synthesis of π‐stacked metallocyclophanes.

Bis(2‐pyridyl)phosphole 1reacted with CuIsources giving rise to dicationic or neutral dimers 2,3. In these derivatives, 1acts as a 1κN:1,2κP:2κNdonor with a symmetrically bridging P centre. X‐ray diffraction studies of these species revealed no constraint due to the unusual coordination mode of the P donor. A comparative study with a monometallic CuIcomplex in which 1acts as a P,N chelate is presented. The acetonitrile ligands of the dicationic complex 2can be displaced by a variety of donors. Bipyridine (bipy) acts as a chelating donor, while 1,1′‐bis(diphenylphosphino)methane (dppm) and bis(2‐pyridyl)phosphole 1behave as bridging ligands. By using dppm and 1, the complexes arising from the stepwise displacement of the acetonitrile ligands of complex 2can be isolated. X‐ray diffraction studies performed on these novel complexes revealed that the P centre can easily switch from a bridging to a semibridging coordination mode. Of particular interest, within the same unit cell, complexes with P centres exhibiting bridging and semibridging coordination modes are observed. This switching can be induced by weak effects such as a different conformation of the incoming ligand. CuIdimers assembled by 1are air‐stable derivatives that are not water sensitive. Hydrolysis of the PF6−counterion occurs under drastic conditions and results in the formation of a PO2F2fragment coordinated to a CuI–1fragment.

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Cyclobutene compounds are interesting intermediates that have proven to be useful in organic synthesis. This review mainly deals with preparations and reactions of some cyclobutenes disubstituted at the allylic position. Several possibilities in the area of the thermal ring opening of these compounds into dienes are explored, and some features of the selectivity of addition reactions to cyclobutenes to afford tri- or tetrasubstituted cyclobutanes are also examined. When suitable leaving groups are present, these cyclobutanes can yield cyclopropanes stereospecifically through ring contraction or bicyclic compounds through intramolecular cyclization. Some applications to the synthesis of nucleoside analogues and of bicyclic compounds are pointed out. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Inhibition of the cysteine protease calpain is a promising strategy for the treatment of muscular dystrophies including Duchenne Muscular Dystrophy. For the treatment to be effective, uptake of the inhibitors into the muscle cells is a prerequisite. A series of α-ketoamide calpain inhibitors carrying various muscle cell targeting capping groups was synthesized. Compounds with charged or highly polar targeting groups were not able to cross the cellular membrane. Introduction of lipoic acid as end cap yielded cell permeable calpain inhibitors with nanomolar potency.

The synthesis of mono- and 1,1‘-diphosphaferrocenes bearing thienyl or phenyl substituents at the PCα carbon is described. Monophosphaferrocenes can be obtained using a “one-pot” procedure involving the oxidative coupling of phenyl- or thienyl-capped octa-1,7-diynes with zirconocene. This route implies a Cp transfer from a Zr species to the iron centers. These novel compounds have been characterized by X-ray diffraction study, and their optical and electrochemical behaviors have been elucidated. These data revealed that the optical gaps vary with the substitution pattern and the nature of the metallocene (mono vs diphosphaferrocenes), whereas their electrochemistry is mainly controlled by the structure of the metallocene. The lowest gaps are obtained with thienyl-substituted mono- and diphosphaferrocenes. Compared to the corresponding oligomers featuring phosphole units, these phosphaferrocene-based compounds exhibit higher thermal stability and higher HOMO−LUMO separation.

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An overview of the synthesis, physical properties, and use as material for organic light-emitting diodes (OLEDs) of linear organic π-conjugated systems incorporating phosphole and thiophene rings is presented.

The synthesis of Pd(II) complexes 2a,c‘, bearing 2-(2-pyridyl)phosphole ligands which act as P,N chelates, is described. Ligands featuring a pendant pyridyl group spontaneously evolve to the corresponding 2-pyridyl-2-phospholene derivatives in the coordination sphere of Pd(II). This isomerization is a stereoselective process, the stereochemistry of the resulting derivatives 3a,a‘ being established by X-ray diffraction studies. The isomerization of ligands lacking pendant pyridyl groups was accomplished by adding pyridine to the reaction media. High yields were achieved under very mild conditions for ligands possessing different substitution patterns. Multinuclear NMR spectroscopic data and X-ray diffraction studies showed that the stereoselectivity of the process is preserved under these new reaction conditions. The transformation did not occur with free 2-(2-pyridyl)phospholes, even at high temperatures in the presence of pyridine. DFT calculations confirmed that coordination to a Pd(II) center is required to make this isomerization thermodynamically feasible. The isomerization has also been demonstrated with Pt(II) precursors but failed with CuCl, CuCl2, and ZnCl2. The free 2-pyridyl-2-phospholenes 4a,c‘ were obtained by reacting the complexes 3a,c‘ with dppe. No inversion of the P atom of the phospholene ring was observed up to 90 °C, indicating that this novel family of P,N chelates is a promising class of ligand for homogeneous catalysis.

Azapeptides are known inhibitors of several serine and cysteine proteases. In seeking different classes of inhibitors for the HCV serine protease, a series of novel azapeptide-based inhibitors were investigated which incorporated noncleavable P1/P1‘ aza-amino acyl residues. Extensive SAR studies around the P1/P1‘ aza-amino acyl fragment resulted in the identification of potent and selective inhibitors. Using NMR studies, we have shown that this series of inhibitors bind in a noncovalent competitive fashion to the NS3 protease active site. The bound conformation of one of these new azapeptide-based inhibitors was determined using the transfer NOE technique. Incorporation of these new aza-amino acyl functionalities in the P1 position provided a handle to probe for new interactions in the S‘ region of the enzyme.

Low-temperature absorption and luminescence spectra of three crystalline nitronyl nitroxides are presented. For 2-(2-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide and 2-(2-benzimidazolyl)-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide, luminescence with resolved vibronic structure is observed between 700 nm and 1100 nm. The modes forming the resolved structure have frequencies of approximately 600 cm−1 and 1400 cm−1. They are characterized by Raman spectroscopy and electronic structure calculations. The intensity distribution within the vibronic progressions indicates small structural changes between the ground and emitting states. The lowest-energy absorption bands observed between 450 nm and 700 nm of the two luminescent compounds and of 2-cyano-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide also show resolved structure, but the overall width of these absorption band systems is larger by a factor of 2 than that of the luminescence spectra. This difference is rationalized in terms of overlapping electronic transitions to at least two excited states arising from the (SOMO − 1)1(SOMO)2 and (SOMO)0(SOMO + 1)1 electron configurations, supported by transition energies and oscillator strengths from density functional calculations.

The present study was aimed at investigating the reduction by hydrogen of an oxygen‐predosed nickel surface at high temperature (530 K) using metastable impact electron spectroscopy (MIES) and UPS (with He(I)) experimental techniques. Both techniques have allowed us to follow the evolution of the electronic structure of the valence band during H2deposition. The work function variation seems to be related directly to the oxygen coverage of the surface and exhibits two stages: an induction period during which no reduction reaction occurs; a rapid reaction period corresponding to the reduction of oxygen. The reaction mechanism entails the formation of hydroxyl compounds but, owing to their thermal desorption at lower temperature in the form of water, no evident OH features have been observed in the MIES and UPS spectra.

The aim of the present study was to investigate the reaction between ammonia and pre‐adsorbed oxygen on Ni at 600 K using metastable impact electron spectroscopy (MIES) and UPS techniques. For a given oxygen‐pretreated nickel surface, the changes in the MIES spectra along with ammonia adsorption can be decomposed into three different steps: a first domain without significant changes, a second domain corresponding to drastic changes in the intensity of a signal at 15.8 eV; and a third domain where no more change is detected. The first domain may correspond to the ammonia chemisorption on the surface, whereas the changes in the second domain would be attributed to surface dehydroxylation. The existence of NHxgroups on the surface has been detected by UPS; they result from ammonia chemisorption. The changes in the MIES spectra have also been studied versus the initial oxygen uptake on Ni. It emerged that the first domain is larger with increasing initial oxygen exposure: this may be explained by the poorer surface reactivity of NiO, contrary to the oxygen‐adsorbed phase. Copyright © 2002 John Wiley & Sons, Ltd.

The aim of the present study was to investigate the reaction between ammonia and pre-adsorbed oxygen on Ni at 600 K using metastable impact electron spectroscopy (MIES) and UPS techniques. For a given oxygen-pretreated nickel surface, the changes in the MIES spectra along with ammonia adsorption can be decomposed into three different steps: a first domain without significant changes, a second domain corresponding to drastic changes in the intensity of a signal at 15.8 eV; and a third domain where no more change is detected. The first domain may correspond to the ammonia chemisorption on the surface, whereas the changes in the second domain would be attributed to surface dehydroxylation. The existence of NHx groups on the surface has been detected by UPS; they result from ammonia chemisorption. The changes in the MIES spectra have also been studied versus the initial oxygen uptake on Ni. It emerged that the first domain is larger with increasing initial oxygen exposure: this may be explained by the poorer surface reactivity of NiO, contrary to the oxygen-adsorbed phase. Copyright © 2002 John Wiley & Sons, Ltd.

Irradiation of the macrolactam 15results in a photo-Fries rearrangement to give the complete diazonamide core skeleton 16in good yield.

Odorant-binding proteins (OBPs) are soluble, low-molecular-weight proteins secreted in the sensillum lymph surrounding the dendrites of olfactory sensilla from a wide range of insect species. These proteins play a role in the solubilization, transport and/or deactivation of pheromones and odorants. In order to study the relationships between the molecular structure in solution and their ligand-binding properties, we have 13C/15N-double-labeled two divergent honeybee OBPs, called ASP1 and ASP2, in sufficient quantities to permit a full determination of the structure and dynamics using heteronuclear NMR spectroscopy. The recombinant labeled proteins produced by the methylotrophic yeast Pichia pastorishave been secreted into a buffered minimal medium using native insect signal peptide. Mass spectrometry and Edman sequencing showed a native-like processing with a labeling efficiency of secreted proteins greater than 98%. After dialysis, the recombinant proteins were purified to homogeneity by one-step reversed-phase liquid chromatography. The final yield after 4-day shake-flask liquid culture was approximately 60 and 100 mg/L for ASP1 and ASP2, respectively. The inexpensive overproduction of labeled recombinant ASP1 and ASP2 should allow NMR studies of the structures and ligand-binding analysis in order to understand the relationships between structure and biological function of these proteins.

Reduction of the uranium(IV) thiolates Cp*2U(SR)2 (Cp* = η-C5Me5, R = Ph, Me, ⁱPr or ^tBu) with sodium amalgam afforded the corresponding U(III) complexes Na[Cp*2U(SR)2] (R = Ph, 2a; Me, 2b; ⁱPr, 2c) or the U(IV) sulfide Na[Cp*2U(S^tBu)(S)]. C−S bond cleavage of a thiolate ligand was also observed during the thermal decomposition of 2c into the sulfide Na[Cp*2U(SⁱPr)(S)], whereas 2b was transformed in refluxing THF into the thiametallacyclopropane complex Na[Cp*2U(SMe)(SCH2)], resulting from C−H bond activation of a SMe group. The X-ray crystal structures of [Na(18-crown-6)(THF)2][Cp*2U(SⁱPr)2], [Na(18-crown-6)][Cp*2U(S^tBu)(S)], and [Na(18-crown-6)(THF)2][Cp*2U(SMe)(SCH2)] have been determined.

Copper(II) complexes of a racemic mixture of a chiral nitronyl-nitroxide are characterised. One, A, is a centro-symmetrical species where two enantiomers are coordinated to a metal centre. The second, B, is a 1D compound comprising bridging ligands through the oxyl and pyridyl donor sites. One observes that, although the crystals are racemic, within a chain, all ligands and metal centres have respectively the same chirality. Possibilities of obtaining optically active extended structures through chiral induction from nitroxide ligands to metal ions are discussed in relation with molecular spin transition species.

AbstractIn this paper is reported a series of Mn(II) complexes with nitronyl nitroxides specifically design to act as bis-chelating ligands. Starting with the mononuclear complexes used as molecular building blocks it is shown how they may polymerise to afford either one dimensional or two dimensional layered compounds exhibiting long-range magnetic ordering.

Deletion mutants of the rabbit progesterone receptor were used to identify two major mechanisms of its nuclear localization. A putative signal sequence, homologous to that of the SV40 large T antigen, was localized around amino acids 638–642 and shown to be constitutively active. When amino acids 638–642 were deleted, the receptor became cytoplasmic but could be shifted into the nucleus by the addition of hormone (or anti-hormone); it was almost fully active. The second mechanism consisted of the activation of the DNA binding domain. By deleting epitopes recognized by monoclonal antibodies, it was possible to follow different receptor mutants inside the same cells. In the absence of ligand, the receptor was transferred into the nucleus as a monomer. After administration of hormone (or anti-hormone) a “cytoplasmic” monomer was transferred into the nucleus through interaction with a “nuclear” monomer. These interactions occurred through the steroid binding domains of both monomers.

Background:A large‐scale standardized patients‐based objective structured clinical examination (OSCE) was introduced in Québec in 1990 for licensing family physicians.Purpose:This article presents the results of a construct validity study conducted on the Spring, 1993 OSCE, using the validation by the extremes method.Methods:Three groups of participants (205 graduating residents, 21 graduating clerks, and 13 general practitioners) were submitted to the same exam. Differences in examination total scores, scores by cases, and scores by skills were analyzed using analysis of variance.Results:The reliability of the examination was 0.80. Clerks obtained significantly lower total results (M = 58.8, SD = 5.6) than residents (M = 70.9, SD = 5.64, p < 0.001); no difference was found between residents’ and family physicians’ total scores (M = 71.3, SD = 4.34, p ‐ 0.662). Cases that were difficult for one group were as difficult for the two other groups.Conclusions:The results support the construct validity of the Quebec licensing examination OSCE, and they confirm that a performance‐based examination for licensure should emphasize comprehension and problem‐solving throughout the assessment of integrative skills such as investigation, diagnosis, and treatment, and that trivialization of checklists should be avoided.

A comprehensive perspective of health provides the framework for the descriptive research reported herein, which investigates some bio-psycho-social dimensions of the health of women and children exposed to violence. During their stay in a shelter for battered women, 130 women who had suffered violence at the hands of their partners were asked to answer a semi-structured questionnaire. The women's perceptions reveal that their symptoms of depression and anxiety correspond to similar behavioral problems in their children. These results must be regarded as a preliminary step towards changes necessary for supporting and promoting healthier family functioning.

Coordination of 2-2-pyridylphospholes on Pdii centres results in a ring strain sufficient to induce a stereospecific 1,3-H migration affording the corresponding phospholene ligands.

The C–S bond cleavage of a thiolate ligand of [U(Cp*)₂(SBu^t)₂] was induced by treatment with Na(Hg) and the title compound was isolated after addition of 18-crown-6; the crystal structure exhibited the unsupported U–S–Na linkage of the molecular complex, with a U–S bond distance of 2.462(2) Å.

The C–S bond cleavage of a thiolate ligand of [U(Cp*)2(SBut)2] was induced by treatment with Na(Hg) and the title compound was isolated after addition of 18-crown-6; the crystal structure exhibited the unsupported U–S–Na linkage of the molecular complex, with a U–S bond distance of 2.462(2) Å.

Human milk is unquestionably the best source of nutrition for infants. Recent publications have emphasized the uniqueness of its bio-chemical composition and particularly of its immunochemical and cellular components.1The renewed interest in providing infants of low birth weight with human milk largely stems from the immunologic protection it confers against infections, allergy, and, to perhaps an appreciable degree, necrotizing enterocolitis. Human milk has come back into favor in intensive care nurseries; consequently there has been a resurgence of interest for human milk banks, which stopped operating in North America shortly after World War II. However, the milk bank tradition was never abandoned in certain British hospitals as well as in Scandinavia. The Helsinki Children's Hospital experience now spans 50 years.2 The collection, processing, and storage of human milk may be initiated to meet the needs of infants of low birth weight, of full-term infants who temporarily cannot

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The reaction of benzothiophenes and thiophenes with symmetrical diarylacetylenes leads to the cleavage of C—Br and C—S bonds and C—H activation in one pot.

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Not as high as Shanghai's Tower(depicted here and in the native city of the two Chinese authors), but π‐stacked columns can be built up by π‐stacked metallocyclophanes, which self‐assemble upon coordination of homoditopic π‐conjugated systems linked to U‐shaped, bimetallic, CuImolecular clips that are stabilized by bridging phosphane ligands. For more details see the Full Paper on page 7143 ff.by R. Réau, C. Lescop et al.