Synthesis of chiral ferrocenylazines. Negishi cross-coupling or S N H reactions?

Preparation of new hetaryl-containing planar chiral ferrocene by a nucleophilic substitution of hydrogen in azines was performed using a lithium derivative of (S)-ferrocenyl-p-tolylsulfoxide as s nucleophilic reagent © 2013 Pleiades Publishing, Ltd

High-power LEDs based on InGaAsP/InP heterostructures

Hig-hpower ligh-temitting diodes (LEDs) wi th mesa diameters of 100, 200, and 300 μ m are devel oped on the basis of InGaAsP/InP heterostructures. The mesas are close in shape to a truncated cone with a generatrix inclination angle of ~45° in the vicinity of the active region of the LED, with a ring etched around the mesa serving as a reflector. The emission spectra and directivity patterns of these LEDs are studied in a wide range of current densities and it is shown that radiative recombination is dominant to a current density of ~5000 A/cm 2 , which makes these structures promising for the development of highpo-er LEDs. An emission power of ~14 mW is obtained in the continuous-wave mode ( I = 0.2 A, λ = 1.1 μ m), and that of 77 mW, in the pulsed mode ( I = 2 A, λ = 1.1 μ m), which corresponds to external quantum efficiencies of 6.2 and 3.4%, respectivel

Influence of divalent cations on the catalytic properties and secondary structure of unadenylylated glutamine synthetase from Azospirillum brasilense

Fully unadenylylated glutamine synthetase (GS) from the endophytic bacterium Azospirillum brasilense Sp245 was isolated and purified. The enzyme was electrophoretically homogeneous and contained strongly bound metal ions, which could not be removed by dialysis. Mn2+, Mg2+, and Co2+ were found to be effective in supporting biosynthetic activity of the A. brasilense GS. Some kinetic properties of Mn2+-activated and Mg2+-activated unadenylylated GS were characterized. Circular dichroism analysis of the enzyme showed that the A. brasilense GS is a highly structured protein: 59% of its residues form alpha -helices and 13% beta -strands. Removal of the metal ions from the A. brasilense GS by treatment with EDTA resulted in alterations in the enzyme secondary structure

Synchronization of modes in WGM‐laser with the connected disk resonators

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