Spectral and thermal studies on copper(II) complexes of acenaphthaquinonemono(4-methylquinolinyl) hydrazone

Cu(II) complexes of acenaphthaquinonemono(4-methylquinolinyl)hydrazone (AMH) of general composition [CuLX₂] (whereL=AMH;X=Cl, Br, I, OAc or NO₃) with the exception of sulphato complex, where the composition is found to be [CuLSO₄]₂ have been synthesized and characterized by elemental analyses, magnetic moment measurements, conductivity measurements, IR, electronic and EPR spectral techniques and by thermal analysis. A planar geometry is indicated for all the complexes. TG curves show one step decomposition of complexes and formation of CU₂O at the end of the step.One of the author (P.K.S.) is thankful to UGC, New Delhi (India), for providing financial assistance and is also indebted to the Department of Chemistry, University of Delhi, Delhi (India) for providing the necessary laboratory facilities.     

Presemiclosed mappings

The purpose of this paper is to investigate the properties of presemiclosed mappings and improve some already established results. Moreover, it is shown that, if the domain space isT ₀, then optimal continuity and homeomorphism coincide (Theorem 4.18).     

High pressure X-ray diffraction and electrical resistance study of the quasi-one-dimensional sulfide InV6S8

The ambient structural details and the results of room temperature high pressure angle dispersive X-ray diffraction and electrical resistance measurements on the quasi-one-dimensional sulfide, InV₆S₈, to a pressure of 25 GPa are reported. The material does not undergo a phase transition in this pressure range, though an anomaly in the c/a ratio has been observed around 10 Gpa. A fit of the Murnaghan equation of state to the V/V₀ versus pressure data, with the value of the derivative of B₀ with respect to pressure, B′₀, fixed at 4 has yielded a value of the bulk modulus, B₀, of 110 GPa. We also present data of the pressure dependence of the lattice constants, a and c, the ratio c/a, and the resistance at room temperature.     

Core level photoemission study of polycrystalline MgB2

X-ray photoemission measurements have been made on Mg 2p and B 1s core levels from MgB₂ as well as on the O 1s core level from the contaminant oxygen. The motivation for this study came for the discrepancy in the reported papers on the energy values of the B 1s and Mg 2p core levels, ostensibly due to the oxygen, present as an impurity, reacting and forming oxides and other compounds. Sputtering leads to a significant reduction of oxygen on and in the sample. The in situ sputter-cleaned sample gives the best results. The measurements are compared with results reported earlier and discrepancies discussed.     

Aqueous bile salt accelerated cascade synthesis of 1,2,3-triazoles from arylboronic acids

A facile, efficient and mild copper catalyzed strategy for cascade synthesis of various 1,4-disubstituted 1,2,3-triazoles from arylboronic acids, sodium azide and alkynes was developed by using aqueous bile salt NaDC solution as an accelerating medium. Low catalyst loading (only 1?mol% Cu source was sufficient for in situ generation of azide followed by azide–alkyne coupling), green solvent, use of bio-surfactant as additive and short reaction time make this protocol highly accessible and environment friendly.     

Macroscopic quantum coherence in ferritin

In a breakthrough experiment, Awschalom et al. [Phys. Rev. Lett. 68, 3092 (1992)] have demonstrated that the antiferromagnetic core in ferritin resonates between two states with oppositely directed Néel vectors, making it the first observation of MQC. A theory has been developed for this resonance including the effect of the 100 or so⁵⁷Fe nuclear spins expected in each ferritin core. Since the hyperfine coupling is known to be ～68 MHz and the MQC frequency is ～1 MHz, the degeneracy of the Néel states, and with it, the MQC resonance, is destroyed in all ferritin particles except those with zero total staggered nuclear spin. From the measured size of λ″(ω), the energy being absorbed by the ferritin is at least 4000 times larger than the maximum permissible. Hence, the true importance of these experiments lies not in the narrow issue of MQC, but in the disproof of long cherished theoretical conservation laws.