Synthesis,crystal structures and fluorescence properties of two new di- and polynuclear Cd(II) complexes with N2O donor set of a tridentate Schiff base ligand

Two new Cd(II) complexes, having one binuclear structure [Cd₂(L)₂(Cl)₂] (1) and another azido bridged one-dimensional zig-zag polynuclear network [Cd₃(μ_1,1-N₃)₄(L)₂{H₂N(CH₂)₂N(C₂H₅)₂} · H₂O]_n (2) have been synthesized from a tridentate N₂O donor Schiff base ligand LH, [LH = (OCH₃)(OH)C₆H₃CHN(CH₂)₂N(C₂H₅)₂], which is the condensation product of 2-hydroxy-4-methoxybenzaldehyde and 2-diethylaminoethylamine. Both the complexes 1 and 2 have been characterized by elemental analyses, IR & ¹H NMR spectroscopy, TGA and fluorescence studies. Finally their structures have been established by single crystal X-ray diffraction method. Structural study reveals that in the complex 1, two Cd(II) centers are held together by two μ₂-phenolato oxygen atoms and the terminal chlorine atom occupies the apical site of the square pyramidal environment of each metal center. In case of complex 2, the trinuclear asymmetric unit contains octahedral Cd(II) centers which are further held together by doubly end-on azido bridging to form a zig-zag polynuclear structure. It also displays intraligand ¹(π–π^∗) fluorescence and can potentially serve as photoactive material.     

Surface area measurement of functionalized single-walled carbon nanotubes

Single-walled carbon nanotubes have been functionalized and the specific surface areas of the functionalized nanotubes measured. Contrary to expectations, functionalization leads to a decrease in specific surface area compared to that of the unfunctionalized nanotubes. Treatment with a concentrated 1:1 nitric/sulfuric acid mixture followed by high-temperature baking at 1000 degrees C was found to increase the specific surface area of the nanotubes. For the unfunctionalized SWNTs, this treatment increases the specific surface area (SSA) by 20%. In the case of SWNTs functionalized by n-butyl groups the increase in the SSA was nearly 2-fold with the value increasing from 410 (drying at 110 degrees C) to 770 m2/gm (acid and bake treatment followed by drying at 110 degrees C). For the ozonized SWNTs, the SSA increases more than 3-fold from 381 (drying at 110 degrees C) to 1068 m2/gm (acid and bake treatment followed by drying at 110 degrees C). SEM images indicate that the nanotubes rebundle in the solid state with an average bundle size of 10-30 nm. AFM studies show that the ozonized tubes have been cut to short bundles after ozonolysis. Hydrogen uptake studies carried out on the baked ozonized tubes led to a 3 wt % hydrogen uptake at 77 K and 30 bar.     

Analysis of a Simplified Model of Rigid Structure Floating in a Viscous Fluid

Journal of Nonlinear Science - We study the interaction of surface water waves with a floating solid constraint to move only in the vertical direction. The first novelty we bring in is that we...     

Pressure effect on the melting point of alkali metals

The mean-square displacement of alkali metals is studied theoretically using our local Heine-Abarenkov-type model potential in the perturbational scheme. The temperature-dependent mean-square displacement of alkali metals decreases as function of the compressed volume. Lindemann's criterion for melting x_m, which is defined as the ratio of two times the root-mean-square displacement to the nearest-neighbour distance, is found to be nearly constant for five alkali metals. The volume effect on the melting temperature of alkali metals is studied by keeping x_m constant. The obtained melting curve increases as function of the compressed volume and are qualitatively in good agreement with the observed tendency for alkali metals.