Magnetic aromaticity

While the neutral 1,2,3,4-oxatriazoles (1) still await synthesis, some of their properties have been predicted by theoretical calculations. AMI calculations combined with a principal component analysis loading data from other related heteroaromatics have been used to estimate geometric characteristics, aromaticity, energy of formation, and N chemical shifts <90JPR885>. The oxatriazoles (1) and (7) and the 1,2,3,5-thiatriazoles, which also have not been prepared, are calculated to be in the group with the lowest classical and magnetic aromaticity. 

Katritzky, A. R. Barczynski, P Musumarra, G. Pisano, D. Szafran, M. Aromaticity as a quantitative concept. 1. A statistical demonstration of the orthogonality of classical and magnetic aromaticity in five- and six-manbered heterocycles, J. Am. Chem. Soc. 1989,777,7-15. 

Caruso, L., Musumarra, G. and Katritzky, A.R. (1993). Classical and Magnetic Aromaticities as New Descriptors for Heteroaromatics in QSAR. Part 3 [1]. Principal Properties for Heteroaromatics. Quant.Struct.-Act.Relat., 12,146-151. 

Caruso, L., Katritzky, A. R., Musumarra, G. Classical and magnetic aromaticities as new descriptors for heteroaromatics in QSAR. Part 3. Principal properties for heteroaromatics. Quant. Struct.-Act. Relat. 1993,12,146-151. 

Principal component analysis has been used to investigate aromaticity as a quantitative concept and revealed a dichotomy between classical and magnetic aromaticity <90JPR853, 90JPR870>. Principal component analysis has also been used to demonstrate a correlation between aromaticity and IR parameters obtained by ab initio 4-31G MO calculations <93JST(10l)97>. 

Classical and magnetic aromaticities of heterocycles have been defined and correlated with biological activities [329]. 

This work resolves, to a considerable extent, the apparent impasse between classical and magnetic aromaticity and provides a firm basis for the consideration of aromaticity as a quantitative concept. It demonstrates that there are at least two types of... 

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