European Journal of Chemistry
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Evaluation of global hardness of atoms based on the commonality in the basic philosophy of the origin and the operational significance of the electronegativity and the hardness. Part I. The Gordy’s scale of electronegativity and the G.H.
Full text linkRelying upon the fact that the hardness, like the electronegativity, is a qualitative property and there is commonality in the basic philosophy of the origin and the operational significance of these two fundamental descriptors of atoms in physics and chemistry, we have proposed to use the Gordy's ansatz, modified by Ghosh and Chakraborty, of evaluating electronegativity of atoms as the ansatz of measuring the global hardness of atoms in this work. The ansatz under reference computes the energy of attraction between the screened nucleus of the atoms and its valence electrons. This is our definition of electronegativity and global hardness of atoms. The evaluated new set of global hardness is found to satisfy the sine qua non of a reasonable scale of hardness by exhibiting perfect periodicity of periods and groups and correlating the gross physico-chemical properties of elements. The inertness of Hg and extreme reactivity of Cs and Fr atoms are nicely correlated. The chemical reactivity and its variation in small steps in the series of lanthanide elements are also nicely reproduced. The results of the present semi-empirical calculation find strong correlation with the results of some sophisticated DFT calculations for a set of atoms
Novel heterocyclic derivatives of pyrano[3,2-c]quinolinone from 3-(1-ethy1-4-hydroxy-2-oxo-2(1H)-quinolin-3-yl)-3-oxopropanoic acid
Full text link3-(1-Ethyl-4-hydroxy-2-oxo-2(1H)-quinolin-3-yl)-3-oxopropanoic acid (2) has been synthesized. The chemical behaviour of β-ketoacid 2 was studied towards condensation reactions with salicylaldelyde, 2-hydroxy-1-naphthaldehyde, 1-phenyl-4-hydroxy-2-oxo-quinoline-3-carboxaldehyde, 2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxalde-hyde, 2-amino-3-formylchromone and its 8-allyl analog, 3-cyanochromone and its 8-allyl analog. Structures of the newly synthesized products have been deduced from their elemental analysis and spectral data
Chiral Cu(II) salen complexes catalyzed aerobic oxidative biaryl coupling-probing the reaction by EPR
Full text linkAerobic oxidative coupling of 2-naphthol to 1,1'-binaphthyl-2,2'-diol has been achieved using chiral/achiral copper salen complexes as catalyst. Moderate enantioselectivity was obtained for the reaction of 2-napthol with a coordinating substituent with a chiral salen complex. Unsubstituted 2-naphthol resulted in racemic 1,1'-binaphthyl-2,2'-diol only with all chiral complexes. Electron paramagnetic resonance spectroscopy has been used to understand the factors influencing the asymmetric induction