Synthesis of new heterocondensed pteridines

Reaction of 2-aminopyrazine 1 with isothiocyanate, isocyanate or dithioketal reagent furnished pteridines 3,4 in good yield. Thioxo compound 3a was chlorinated, methylated and subsequently displaced by amines. A simple one-step synthesis of heterocondensed pteridines 8–13 by reaction of 2-aminopyrazine with various imino thioacetals was described 8–13 .     

Fluorescence from relaxed and unrelaxed excited state of benzil

This note reports the detection of fluorescence from unrelaxed S₁ state of benzil using Boxcar gating technique. The new emission exhibits mirror image relationship with absorption and blue shift in hydroxylic solvent. In order to ascertain wheter geometrical relaxation occurs in S₁ state, intensities of fluorescence from relaxed and unrelaxed state have been compared at various temperatures.     

Shell model yrast states of the N=83 nucleus 150Ho

Studies of delayed γ-rays from the reactions ¹²²Te(³²S, p3n) and ¹²¹Sb(³²S, 3n) have located high-spin excitations in ¹⁵⁰Ho up to a 92 ± 8 ns isomer at 2625 keV. The main yrast level sequence is found to agree closely with shell model predictions (based on an inert ¹⁴⁶Gd core) of level energies, isomeric half-life and deexcitation pathway for the $\text{(πh}{}_{\mathrm{<mtext>11</mtext><mtext>2</mtext>}}\text{)}{}^3\text{vf}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ configuration.     

Influence of alloy composition on the dependence of the diffusivity-mobility ratio in ternary semiconductors on a quantizing magnetic field

An expression is derived for the diffusivity-mobility ratio in degenerate narrow-gap ternary semiconductors in the presence of a quantizing magnetic field. With the help of this expression, the diffusivity-mobility ratio is shown, taking n-Hg_1–xCd_xTe as an example, to have an oscillatory dependence on a quantizing magnetic field. The influence of alloy composition on such dependence is also investigated.     

First synthesis of lower-rim-substituted aryl ethers of p-tert-butylcalix[4]arene

With the use of S(N)Ar or Ullmann reactions, the synthesis of the first lower-rim aryl ether derivatives of tert-butylcalix[4]arene is reported, as are some of their conformational properties, (1)H NMR spectra, and X-ray crystal structures. The lower-rim aryl pendants reported herein provide for new scaffolds upon which a host of other new molecular architectures can be constructed, thus extending the capability of the versatile calix[4]arenes even further.     

High‐Efficiency Perovskite Solar Cells Enabled by Anatase TiO2 Nanopyramid Arrays with an Oriented Electric Field

One‐dimensional (1D) nanostructured oxides are proposed as excellent electron transport materials (ETMs) for perovskite solar cells (PSCs); however, experimental evidence is lacking. A facile hydrothermal approach was employed to grow highly oriented anatase TiO₂ nanopyramid arrays and demonstrate their application in PSCs. The oriented TiO₂ nanopyramid arrays afford sufficient contact area for electron extraction and increase light transmission. Moreover, the nanopyramid array/perovskite system exhibits an oriented electric field that can increase charge separation and accelerate charge transport, thereby suppressing charge recombination. The anatase TiO₂ nanopyramid array‐based PSCs deliver a champion power conversion efficiency of approximately 22.5 %, which is the highest power conversion efficiency reported to date for PSCs consisting of 1D ETMs. This work demonstrates that the rational design of 1D ETMs can achieve PSCs that perform as well as typical mesoscopic and planar PSCs.     

Design and Synthesis of ZnII‐Coordination Polymers Anchored with NSAIDs: Metallovesicle Formation and Multi‐drug Delivery

A series of coordination polymers synthesized from a bis‐pyridyl linker, namely 4,4′‐azopyridine ( L ), selected non‐steroidal‐anti‐inflammatory drugs (NSAIDs), namely diclofenac ( Dic ), ibuprofen ( Ibu ), flurbiprofen ( Flu ), mefenamic acid ( Mefe ), and naproxen ( Nap ), and Zn(NO₃)₂ were characterized by single crystal X‐ray diffraction. One of the coordination polymers, namely CP3 derived from Flu , was able to form metallovesicles in DMSO, DMSO/H₂O and DMSO/DMEM (biological media) as revealed by TEM, AFM and DLS. Metallovesicle formation by CP3 was further supported by loading a fluorescent dye, namely calcein, as well as an anti‐cancer drug, doxorubicin hydrochloride ( DOX ), as revealed by UV‐vis and emission spectra, and fluorescence microscopy. DOX ‐loaded metallovesicles of CP3 ( DOX@CP3‐vesicle ) could be delivered in vitro to a highly aggressive human breast cancer cell line, namely MDA‐MB‐231, as revealed by MTT and cell migration assays, and also cell imaging performed under laser scanning confocal microscope (LSCM). Thus, a proof of concept for developing a multi‐drug delivery system derived from a metallovesicle for delivering an anti‐cancer drug to cancer cells is demonstrated for the first time.     

Adsorptive parameters and influence of hot geometries on the SER(R) S spectra of methylene blue molecules adsorbed on gold nanocolloidal particles

The vibrational signatures of methylene blue (MB) dye molecule have been reported. Complete vibrational assignments of the molecule are presented for the first time. Concentration‐dependent surface enhanced resonance Raman scattering [SER(R) S] spectra of the molecule have been investigated. Fluorescence spectroscopic technique has been applied to explore the concentration of the probe molecule actually adsorbed on the gold nanocolloidal (AuNC) surface. The free energy of adsorption and saturated concentration of MB molecules on AuNC surface are also estimated. Gigantic enhancements ~10⁵–10¹³ orders of magnitude have been recorded for the enhanced Raman bands in the SER(R) S spectra. The possible orientation of the molecule on the AuNC surface and their probable protrusions within the hot spots have been suggested. The hot geometries and correlation between the plasmonic behavior of the nanoparticles and enhancement efficiencies of the SER(R) S band have been mapped with the aid of three‐dimensional finite difference time domain (3D‐FDTD) simulations. Application of soft lithographic technique to engineer the pattern formation of hetero dimeric spherical aggregates will be an interesting field of study in future to enhance the detection limit of this and similar types of dye molecules. Copyright © 2015 John Wiley & Sons, Ltd.