Aromaticity estimation

Quantum-chemical calculations for pyrylium including one, two, or three water molecules using DFT and 6-31 + G(d,p) basis set revealed that the aromaticity (estimated by harmonic oscillator stabilization energy, HOSE natural resonance theory, NRT harmonic oscillator model of aromaticity, HOMA and nucleus-independent chemical shifts, NICS) is not influenced by water molecules [82],... 

Boron neutron capture therapy, isoxazoline deriv, 60, 297 Boroxine, aromaticity estimates/indices,... 

Aromaticity Estimation by Air Oxidation. Aromaticity of a lake humic acid was estimated by the method established by Mazumdar et al. (1959) for coal (Ishiwatari, 1969a). The method consists of heating powdered humic acid at 170°C for a long period (e.g., 600 hours) under a current of air. End-groups of humic acid are oxidized to carbon dioxide by this treatment, leading to the formation of hydroxyl, carbonyl, and carboxyl groups while the aromatic skeleton remains unaffected. Thus, carbon aromaticity (a ratio of aromatic... 

Katritzky et al. [88] and Jug [89] and others [14,22,57] have shown recently that aromaticity is a multidimensional phenomenon. For this purpose they applied statistical methods (the principal component or factor analyses [51,90,91]) which need application of many indices of aromaticity estimated (experimentally or calculated theoretically) for many molecular systems. Thus their conclusion is of great general importance but no information may be extracted for any individual molecule or its fragment. The method presented above, the separation of HOMA value into EN and GEO terms, allows us to describe numerically which of these two factors is... 

We continue this review with a discussion of local aromaticities estimated by EC values in comparison with other methods. Among the many pubhshed approaches to this problem, pioneered by Oskar Polansky (Polansky and Derflinger 1967 Monev et al. 1981) which were presented in Part 6 of our series, entitled Partitioning of u-electrons in rings of polycyclic conjugated hydrocarbons. 

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