Ferrimagnetic coupling in oxamido-bridged Mn(II)Cu(II) compounds: a combined CASPT2 and DDCI study

Multiconfigurational perturbation theory (CASPT2) and difference dedicated configuration interaction (DDCI) are applied to study the ferrimagnetic coupling in an oxamido-bridged Mn(II)Cu(II) molecular species. CASPT2 reproduces the experimental coupling very well. From the partition of the CASPT2 energy, the most important contributions to the coupling are established. Spin populations are calculated with DDCI. The successive improvement of the N-electron wave function allows us to analyse the contributions to the spin delocalization.     

The Assignment of the 1600 cm−1 Mystery Band of Carbons

Abstract

The assignment of a band near 1600 cm^?1 in IR spectra of carbons has been controversial for four decades. However, many different carbons have been studied: effectively, a single band assignment was sought for an absorption appearing with three different classes of carbon. As these differ in over-all structure, not one but three explanations are needed. These are discussed. However, undue emphasis has been placed on a single absorption; attention should also be paid to other absorptions accompanying the 1600 cm^?1 band.     

Moisture barrier of AlxOy coating on poly(ethylene terephthalate), poly(ethylene naphthalate) and poly(carbonate) substrates

The moisture barrier property of Al_xO_y coated poly(ethylene terephthalate) (PET), poly(ethylene naphthalate) (PEN) and poly(carbonate) (PC), have been investigated. The differences in the morphology of the Al_xO_y sputtered grown on these substrate were investigated using atomic force microscopy (AFM). The initial growth of the Al_xO_y followed closely the topology of the substrate and an amplified roughness was observed. In the fully grown Al_xO_y, the comparative roughness followed that of the substrates. It has been found that a single layer Al_xO_y improved the moisture barrier of PET by an order of magnitude, PC by two orders of magnitude while no improvement was observed for PEN. UV-ozone treatment on PC further improved the moisture barrier, while no improvement was observed for PET and PEN. The comparative effects of the substrate surface roughness and surface energy on the moisture barrier are discussed.     

High-performance liquid chromatography of ternary nickel dithiocarbamate complexes derived from some sympathomimetic drugs

Summary Nickel dithiocarbamate complexes derived from some sympathomimetic drugs are examined on silica Radial-Pak columns using binary solvents containing a small percentage of an organic polar modifier. Both the type and concentration of this modifier was found to influence the separation of the ternary from the parent binary complexes. When the two ligands in a ternary complex are racemic to each other, separation of the ternary complex is only possible when certain structural requirements of the molecule are fulfilled. Ternary complexes which contain structurally similar, but nonracemic ligands, are shown to be readily separated from binary complexes. When two such complexes differ only in that one of the ligands in one is enantiomeric to a ligand in the second complex, then it can be shown that the ternary complex with the (+) enantiomer ligand elutes faster from the silica column than the one with the (–) enantiomer ligand. An example of the use of ternary complexes for the identification of optical and structurally related impurities in pharmaceutical products is also given.