DUGi

Why 1,2-quinone derivatives are more stable than their 2,3-analogues?

http://dugi.udg.edu/item/http:@@@@hdl.handle.net@@2072@@296605

In this work, we have studied the relative stability of 1,2- and 2,3-quinones. While 1,2-quinones have a closed-shell singlet ground state, the ground state for the studied 2,3-isomers is open-shell singlet, except for 2,3-naphthaquinone that has a closed-shell singlet ground state. In all cases, 1,2-quinones are more stable than their 2,3-counterparts. We analyzed the reasons for the higher stability of the 1,2-isomers through energy decomposition analysis in the framework of Kohn–Sham molecular orbital theory. The results showed that we have to trace the origin of 1,2-quinones’ enhanced stability to the more efficient bonding in the π-electron system due to more favorable overlap between the SOMOπ of the ·C4n−2H2n–CH·· and ··CH–CO–CO· fragments in the 1,2-arrangement. Furthermore, whereas 1,2-quinones present a constant trend with their elongation for all analyzed properties (geometric, energetic, and electronic), 2,3-quinone derivatives present a substantial breaking in monotonicity

This work has been supported by the European Union in the framework of European Social Fund through the Warsaw University of Technology Development Programme. O.A. S., H. S. and T.M. K. gratefully acknowledge the Foundation for Polish Science for supporting this work under MPD/2010/4 project "Towards Advanced Functional Materials and Novel Devices-Joint UW and WUT International PhD Programme" and the Interdisciplinary Center for Mathematical and Computational Modeling (Warsaw, Poland) for providing computer time and facilities. Thanks are also to the Ministerio de Economia y Competitividad of Spain (Projects CTQ2011-23156/BQU and CTQ2011-25086) and the Generalitat de Catalunya (project numbers 2014SGR931, Xarxa de Referencia en Quimica Teorica i Computacional, and ICREA Academia 2014 prize for MS)

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