title: Conjugation paths in monosubstituted 1,2- and 2,3-naphthoquinones.
abstract: Optimization of monosubstituted (X = NO, NO(2), CN, CHO, Me, OMe, OH, NH(2), NHMe, and N(Me)(2)) derivatives of 1,2- and 2,3-naphthoquinone by use of B3LYP with the 6-311+G** basis set applying the GAUSSIAN03 program allowed us to analyze the character of interactions between the substituents and the carbonyl groups. It is shown that only one of two carbonyl groups exhibited substantial substituent effect evidenced by regression of the CO bond length and delocalization index, DI(CO) on the Hammett substituent constants, σ(p), with a very high correlation coefficient, whereas the other one did not depend in any substantial way on σ(p). Dependences of conjugation path built up of bonds between substituent and oxygen atoms of carbonyl groups on σ(p), give more acceptable correlations if the number of bonds in the path is even than in cases when they are odd.
authors: Department of Chemistry, College of Sciences, Shiraz University, Shiraz, Iran.
authors: Mozhgan
authors: M
authors: Shahamirian
authors: Michał K
authors: MK
authors: Cyrański
authors: Tadeusz M
authors: TM
authors: Krygowski
mesh_terms: D015394:Molecular Structure; D009285:Naphthoquinones / Q000737:chemistry*; D011789:Quantum Theory; D013237:Stereoisomerism
chemical_list: D009285:Naphthoquinones