five new aromatic poly(amide-imide)s (5a-e) were synthesized by direct polycondensationreaction of n-(4-carboxy phenyl) trimellitimide (3) with five aromatic diamines (4a-e) by usingtriphenyl phosphite in n-methyl-2-pyrrolidone (nmp) and pyridine at solution containingdissolved cacl2. all of the polymers were obtained in quantitative yields with inherentviscosities between 0.29-0.40 dl/g. the r...

The previous discoveries of butyl fenbufen amide analogs with antitumor effects were further examined. The amide analogs with 1, 3, 4 and 8 carbons chains were prepared in 70-80% yield. Fenbufen had no cytotoxic effects at concentrations ranging from 10 to 100 μM. Methyl fenbufen amide had significant cytotoxic effects at a concentration of 100 μM. As the length of the alkyl amide side chain in...

The antharquinone-based chromophore of 11-hydroxyaklavinone is present in the structure of an anticancer agent, daunomycin. On the other hand, aklavinone is the parent aglycone of certain anthracycline antibiotics that possess anti-cancer activity too. The structures of aklavinone and its 11-hydroxy derivative have many -OH groups, and two keto groups which may take place in certain tautomeric ...

We have isolated the stable as well as the metastable tautomers of 1-deazapurine in the solid state by exploiting principles of supramolecular selectivity in the context of cocrystal design.

Efficient generation of hydrogen from renewable resources requires development of catalysts that avoid deep wells and high barriers. Information about the energy landscape for H2 production can be obtained by chemical characterization of catalytic intermediates, but few have been observed to date. We have isolated and characterized a key intermediate in 2e(-) + 2H(+) → H2 catalysis. This interm...

Attractive interactions between two carboxamide groups in a "stacked" geometry are explored under isolated molecule conditions. Infrared spectra of single conformations of a small gamma-peptide, Ac-gamma(2)-hPhe-NHMe, reveal the presence of a conformation in which the two amide planes are approximately parallel with the amide dipoles in an antialigned orientation. This stacked conformation is e...

We demonstrate how multimode 2D IR spectroscopy of the protein amide I' and II' vibrations can be used to distinguish protein secondary structure. Polarization-dependent amide I'-II' 2D IR experiments on poly-l-lysine in the beta-sheet, alpha-helix, and random coil conformations show that a combination of amide I' and II' diagonal and cross peaks can effectively distinguish between secondary st...

a classical theory is developed which calculates the momentum transfer rate constant between an ion and a non-polar molecule. the model takes into consideration the effect of diffraction outside the capture limit on the rate constants. the theory is used to calculate momentum transfer rate constant for cl- with trans-dichloroethylene and para-difluorobenzene. theoretical results are compared to...