one series of half-analogues of michler’s ketone containing one or more terminal methoxysubstituents with variable tertiary amino groups have been used in this study. nmr spectralresults for the parent ketones confirm earlier findings that ortho proton shifts are apparentlyindependent from steric effects in derivatives of michler’s ketone because the ring current andcarbonyl-induced shifts are ...

The solvent effect on the position of the carbonyl vibrational stretching of acetylferrocene in aprotic media was studied in this work. The solvent-induced shifts in this organometallic compound were interpreted in terms of the alternative reaction field model(SCRF-MO) proposed by Kolling. In contrast to the established trends for carbonyl groups in organic systems, the results suggest that the...

Li(+) and Ca(2+) binding to the carbonyl oxygen sites of a model peptide system has been studied by (17)O solid-state NMR spectroscopy. (17)O chemical shift (CS) and quadrupole coupling (QC) tensors are determined in four Gly-(Gly-(17)O)-Gly polymorphs by a combination of stationary and fast magic-angle spinning (MAS) methods at high magnetic field, 19.6 T. In the crystal lattice, the carbonyl ...

A platinum-catalyzed reaction involving new aromatization/1,3-carbonyl shift cascade of 2-epoxy-1-(methoxyalk-2-ynyl)benzenes is reported. This skeletal rearrangement is mechanistically significant because it involves a remarkable 1,3-carbonyl shift to complete the aromatization and to regenerate the catalyst.

63Cu NMR spectroscopic studies of copper(I) complexes with various N-donor tridentate ligands are reported. As has been previously reported for most copper(I) complexes, 63Cu NMR signals, when acetonitrile is coordinated to copper(I) complexes of these tridentate ligands, are broad or undetectable. However, when CO is bound to tridentate copper(I) complexes, the 63Cu NMR signals become much sha...

conclusions the adoption of 85 dba as the permissible exposure limit has preserved hearing threshold level among participants at 3000 hz compared to those who embraced 90 dba. patients and methods this is an intervention study done on two automobile factories. there were 203 employees exposed to noise levels beyond the action level. hearing protection devices were distributed to reduce noise le...

we compared the extent of temporary threshold shift (tts) and hair cell loss following high level 4 khz noise exposure with those preconditioned with moderate level 1 and 4 khz octave band noise. fifteen male albino guinea pigs (300- 350 g in weight) were randomly allocated into three groups: those exposed to 4 khz octave band noise at 102 db spl (group 1, n=5); those conditioned with 1 khz oct...

This study was conducted to evaluate the cytoprotection of various extracts and bioactive compounds found in Pistacia vera againts cytotoxicity, ROS formation, lipid peroxidation, protein carbonylation , mitochondrial and lysosomal membrane damages in cell toxicity models of diabetes related carbonyl (glyoxal) and oxidative stress (hydroperoxide). Methanol, water and ethyl acetate were used to ...

This study was conducted to evaluate the cytoprotection of various extracts and bioactive compounds found in Pistacia vera againts cytotoxicity, ROS formation, lipid peroxidation, protein carbonylation , mitochondrial and lysosomal membrane damages in cell toxicity models of diabetes related carbonyl (glyoxal) and oxidative stress (hydroperoxide). Methanol, water and ethyl acetate were used to ...

An n = π* interaction between neighboring carbonyl groups has been postulated to stabilize protein structures. Such an interaction would affect the (13)C chemical shielding of the carbonyl groups, whose paramagnetic component is dominated by n = π* and π = π* excitations. Model compound calculations indicate that both the interaction energetics and the chemical shielding of the carbonyl group a...