Rotationally resolved electronic spectroscopy of water clusters of 7-azaindole

The rotationally resolved electronic spectra of the electronic origin of the 7-azaindole-(H(2)O)(1) and of the 7-azaindole-(H(2)O)(2) clusters have been measured in a molecular beam. From the rotational constants the structures in the S(0) and S(1) electronic states were determined as cyclic with the pyrrolo NH and the pyridino N atoms being bridged by one and two water molecules, respectively. Excited state lifetimes of about 10 ns for both clusters have been found. In the spectrum of the 7-azaindole-(H(2)O)(2) cluster a splitting of the rovibronic band is observed, which can be traced back to a large amplitude motion, involving the out-of-plane hydrogen atoms of the water chain. Both the changes of the rotational constants upon electronic excitation and the orientation of the transition dipole point to a solvent induced state reversal between the L(a) and the L(b) states upon microsolvation.     

Anomalous temperature-dependent photoluminescence characteristic of as-grown GaInNAs/GaAs quantum well grown by solid source molecular beam epitaxy

The photoluminescence (PL) mechanisms of as-grown GaInNAs/GaAs quantum well were investigated by temperature-dependent PL measurements. An anomalous two-segmented trend in the PL peak energy vs. temperature curve was observed, which has higher and lower temperature-dependent characteristics at low temperature (5–80 K) and high temperature (above 80 K), respectively. The low and high-temperature segments were fitted with two separate Varshni fitting curves, namely Fit_low and Fit_high, respectively, as the low-temperature PL mechanism is dominated by localized PL transitions while the high-temperature PL mechanism is dominated by the e1–hh1 PL transition. Further investigation of the PL efficiency vs. 1/kT relationship suggests that the main localized state is located at 34 meV below the e1 state. It is also found that the temperature (80 K) at which the PL full-width at half-maximum changes from linear trend to almost constant trend correlates well with the temperature at which the PL peak energy vs. temperature curve changes from Fit_low to Fit_high.     

Fe2O3/Mn2O3 nanoparticles: Preparations and applications in the photocatalytic degradation of phenol and parathion in water

In this study, nanoparticles of Fe₂O₃/Mn₂O₃ mixture were obtained using the sol–gel method. The synthesis uses the combination of polyvinyl alcohol (PVA) and tartaric acid (TA). Synthesized catalysts prove superior compared to those afforded from previous reports. To be specific, desired catalysts can be received at lower calcination temperature. Furthermore, their structures display higher uniformity in term of particle sizes. Finally, they show better performance for the photocatalytic degradation of model-persistent organic compounds.     

Metalated nitriles: chelation-controlled cyclizations to cis and trans hydrindanes and decalins

Chelation provides a powerful means of stereocontrol in alkylations of metalated nitriles. Doubly deprotonating a series of cyclic beta-hydroxynitriles triggers cyclizations that implicate metalated nitrile intermediates having configurations imposed by chelation with an adjacent, chiral lithium alkoxide. Identifying chelation as a general stereocontrol element explains several previously anomalous alkylations of metalated nitriles and provides a potential solution to the long-standing difficulty of synthesizing trans-hydrindanes. Employing chelation to control the metalated nitrile geometry permits selective cyclizations to cis and trans hydrindanes and decalins and provides key insight into the geometrical requirements of these demanding cyclizations.     

Uniqueness Theorems for Holomorphic Curves with Hypersurfaces of Fermat–Waring Type

In this paper, we establish uniqueness theorems for holomorphic mappings from \(\mathbb C\) to \(P^N({\mathbb C}) \) for the case where the targets are not hyperplanes, but hypersurfaces of Fermat–Waring type.     

Asymptotic Number of Scattering Resonances for Generic Schrödinger Operators

Let ?Δ + V be the Schrödinger operator acting on ${L^2(\mathbb{R}^d,\mathbb{C})}$ with ${d\geq 3}$ odd. Here V is a bounded real or complex function vanishing outside the closed ball of center 0 and of radius a. Let n _V (r) denote the number of resonances of ?Δ + V with modulus ≤  r. We show that if the potential V is generic in a sense of pluripotential theory then $$n_V(r)=c_d a^dr^d+ O(r^{d-{3\over 16}+\epsilon}) \quad \mbox{as } r \to \infty$$ for any ε > 0, where c _d is a dimensional constant.     

Random matrices: Universality of local eigenvalue statistics

In this paper, we consider the universality of the local eigenvalue statistics of random matrices. Our main result shows that these statistics are determined by the first four moments of the distribution of the entries. As a consequence, we derive the universality of eigenvalue gap distribution and k-point correlation, and many other statistics (under some mild assumptions) for both Wigner Hermitian matrices and Wigner real symmetric matrices.     

Regio- and stereoselective synthesis of truncated 3'-aminocarbanucleosides and their binding affinity at the A3 adenosine receptor

The stereoselective synthesis of truncated 3'-aminocarbanucleosides 4a-d via a stereo- and regioselective conversion of a diol 9 to bromoacetate 11a and their binding affinity towards the human A(3) adenosine receptor are described.     

A well-defined silica-supported aluminium alkyl through an unprecedented, consecutive two-step protonolysis-alkyl transfer mechanism

Impregnation of [(AliBu(3))(Et(2)O)] on partially dehydroxylated SBA-15 affords a mesoporous material bearing the well-defined single site surface aluminium species [(≡SiO)(2)Al(iBu)(Et(2)O)].     

Viscometric and Morphological Properties of Novel Magnesium Electrolyte–Polyacrylamide Composite Polymers in Aqueous Solution

The viscometric properties of novel magnesium electrolyte–polyacrylamide composite polymers in aqueous solutions were investigated using response surface methodology. Independent factors such as concentration of the magnesium electrolyte (magnesium chloride and magnesium hydroxide), concentration of polyacrylamide, and the solution temperature were taken into account for viscometric modeling. Experiments were carried out according to central composite design, which includes factorial, central and axial points of the factors. Solution viscosity was taken as the response variable. A polynomial model for the viscometric properties was developed using ANOVA and non-linear regression analysis, and the R² values are 0.9995 and 0.9996 for aqueous solutions of magnesium chloride–polyacrylamide (MCPAM) and magnesium hydroxide–polyacrylamide (MHPAM) composite polymers, respectively. Two diagnostic plots have been constructed to validate the developed models for the natural logarithm of viscosity of aqueous solutions of the MCPAM and MHPAM composite polymers. The least-squares values show that the developed models are adequate for predictive purposes. TEM was used to investigate the morphological properties of MCPAM and MHPAM composite polymers. Magnesium chloride was impregnated into the polyacrylamide chain while magnesium hydroxide was just adsorbed on the surface of the polyacrylamide chain.