Oxidative reactions of 6-pentyl indolo[3,2-b]carbazole: formation of novel C-C and C-N coupled dimers

The oxidative coupling reactions of 6-pentyl-5,11-dihydroindolo[3,2-b]carbazole have been studied and as a result, a number of novel dimers of the indolo[3,2-b]carbazole derivative have been prepared, forming C-C coupled compound when treated with FeCl(3) x 6H(2)O or C-N coupled compounds and when oxidized with air or Pd(OAc)(2), respectively.     

Development of an efficient amine-functionalized glass platform by additional silanization treatment with alkylsilane

Aminosilane-treated molecular layers on glass surfaces are frequently used as functional platforms for biosensor preparation. All the amino groups present on the surface are not available in reactive forms, because surface amino groups interact with remaining unreacted surface silanol groups. Such nonspecific interactions might reduce the efficiency of chemical immobilization of biomolecules such as DNA, enzymes, antibodies, etc., in biosensor fabrication. To improve immobilization efficiency we have used additional surface silanization with alkylsilane (capping) to convert the remaining silanol groups into Si–O–Si linkages, thereby liberating the amino groups from nonspecific interaction with the silanol groups. We prepared different types of capped amine surface and evaluated the effect of capping on immobilization efficiency by investigating the fluorescence intensity of Cy3-NHS (N-hydroxysuccinimide) dye that reacted with amino groups. The results indicate that most of the capped amine surfaces resulted in enhanced efficiency of immobilization of Cy3-NHS compared with the untreated control amine surface. We found a trend that trialkoxysilanes had greater capping effects on immobilization efficiency than monoalkoxysilanes. It was also found that the aliphatic chain of alkylsilane, which does not participate in the capping of the silanol, had an important function in enhancing immobilization efficiency. These results would be useful for preparation of an amine-modified surface platform, with enhanced immobilization efficiency, which is essential for developing many kinds of biosensors on a silica matrix. Enhancement of amine funtionality by capping with alkylsilane     

Efficiency and equity in private and public education: A nonparametric comparison

We present a nonparametric approach for (1) efficiency and (2) equity evaluation in education. Firstly, we use a nonparametric (Data Envelopment Analysis) model that is specially tailored to assess educational efficiency at the pupil level. The model accounts for the fact that typically minimal prior structure is available for the behavior (objectives and feasibility set) under evaluation. It allows for uncertainty in the data, while it corrects for exogenous ‘environmental’ characteristics that are specific to each pupil. Secondly, we propose two multidimensional stochastic dominance criteria as naturally complementary aggregation criteria for comparing the performance of different school types (private and public schools). While the first criterion only accounts for efficiency, the second criterion also takes equity into consideration. The model is applied for comparing private (but publicly funded) and public primary schools in Flanders. Our application finds that no school type robustly dominates another type when controlling for the school environment and taking equity into account. More generally, it demonstrates the usefulness of our nonparametric approach, which includes environmental and equity considerations, for obtaining ‘fair’ performance comparisons in the public sector context.     

Quadrupole Transitions in the Bound Rotational-Vibrational Spectrum of the Hydrogen Molecular Ion

The three-body Schrödinger equation of the ${{\rm H}_{2}^{+}}$ hydrogen molecular ion is solved in perimetric coordinates using the Lagrange-mesh method. Energies and wave functions of the four lowest vibrational bound or quasibound states for total orbital momenta from 0 to 40 are calculated with high accuracy. A simple calculation using the associated Gauss quadrature provides accurate quadrupole transition probabilities per time unit between those states over the whole rotational bands.     

Self-Assembly Behavior and Application of Terphenyl-Cored Trimaltosides for Membrane-Protein Studies: Impact of Detergent Hydrophobic Group Geometry on Protein Stability

Amphipathic agents are widely used in various fields including biomedical sciences. Micelle-forming detergents are particularly useful for in vitro membrane-protein characterization. As many conventional detergents are limited in their ability to stabilize membrane proteins, it is necessary to develop novel detergents to facilitate membrane-protein research. In the current study, we developed novel trimaltoside detergents with an alkyl pendant-bearing terphenyl unit as a hydrophobic group, designated terphenyl-cored maltosides (TPMs). We found that the geometry of the detergent hydrophobic group substantially impacts detergent self-assembly behavior, as well as detergent efficacy for membrane-protein stabilization. TPM-Vs, with a bent terphenyl group, were superior to the linear counterparts (TPM-Ls) at stabilizing multiple membrane proteins. The favorable protein stabilization efficacy of these bent TPMs is likely associated with a binding mode with membrane proteins distinct from conventional detergents and facial amphiphiles. When compared to n-dodecyl-β-d -maltoside (DDM), most TPMs were superior or comparable to this gold standard detergent at stabilizing membrane proteins. Notably, TPM-L3 was particularly effective at stabilizing the human β₂ adrenergic receptor (β₂AR), a G-protein coupled receptor, and its complex with G_s protein. Thus, the current study not only provides novel detergent tools that are useful for membrane-protein study, but also suggests a critical role for detergent hydrophobic group geometry in governing detergent efficacy.     

Spectral,crystallographic, theoretical and antibacterial studies of palladium(II)/platinum(II) complexes with unsymmetric diphosphine ylides

The reaction of α‐keto‐stabilized diphosphine ylides [Ph₂P(CH₂)_nPPh₂═C(H)C(O)C₆H₄‐p‐CN] (n = 1 (Y¹); n = 2 (Y²)) with dibromo(1,5‐cyclooctadiene) palladium(II)/platinum(II) complexes, [Pd/PtBr₂(cod)], in equimolar ratio gave the new cyclometalated Pd(II) and Pt(II) complexes [Br₂Pd(κ²‐Y¹)] ( 1 ), [Br₂Pt(κ²‐Y¹)] ( 2 ), [Br₂Pd(κ²‐Y²)] ( 3 ) and [Br₂Pt(κ²‐Y²)] ( 4 ). These compounds were screened in a search for novel antibacterial agents and characterized successfully using Fourier transfer infrared and NMR (¹H, ¹³C and ³¹P) spectroscopic methods. Also, the structures of complexes 1 and 2 were characterized using X‐ray crystallography. The results showed that the P,C‐chelated complexes 1 and 2 have structures consisting of five‐membered rings, while 3 and 4 have six‐membered rings, formed by coordination of the ligand through the phosphine group and the ylidic carbon atom to the metal centre. Also, a theoretical study of the structures of complexes 1 – 4 was conducted at the BP86/def2‐SVP level of theory. The nature of metal–ligand bonds in the complexes was investigated using energy decomposition analyses (EDA) and extended transition state combined with natural orbitals for chemical valence analyses. The results of EDA confirmed that the main portions of ΔE_int, about 57–58%, in the complexes are allocated to ΔE_elstat.     

The photon-ion merged-beams experiment PIPE at PETRA III—The first five years

The Photon-Ion Spectrometer at PETRA III—in short, PIPE—is a permanently installed user facility at the "Variable Polarization XUV Beamline" P04 of the synchrotron light source PETRA III operated by DESY in Hamburg, Germany. The careful design of the PIPE ion-optics in combination with the record-high photon flux at P04 has lead to a breakthrough in experimental studies of photon interactions with ionized small quantum systems. This short review provides an overview over the published scientific results from photon-ion merged-beams experiments at PIPE that were obtained since the start of P04 operations in 2013. The topics covered comprise photoionization of ions of astrophysical relevance, quantitative studies of multi-electron processes upon inner-shell photoexcitation and photoionization of negative and positive atomic ions, precision spectroscopy of photoionization resonances, photoionization and photofragmentation of molecular ions, and of endohedral fullerene ions.     

A Mechanistically and Operationally Simple Route to Metal–N-Heterocyclic Carbene (NHC) Complexes

We have been puzzled by the involvement of weak organic and inorganic bases in the synthesis of metal–N-heterocyclic carbene (NHC) complexes. Such bases are insufficiently strong to permit the presumed required deprotonation of the azolium salt (the carbene precursor) prior to metal binding. Experimental and computational studies provide support for a base-assisted concerted process that does not require free NHC formation. The synthetic protocol was found applicable to a number of transition-metal- and main-group-centered NHC compounds and could become the synthetic route of choice to form M–NHC bonds.