Stability of functionalized corannulene cations [R-C20 H10 ](+) : An influence of the nature of R-Group.

Abstract

The first comprehensive theoretical study of stability of hub-functionalized corannulene cations [R-C20 H10 ](+) as the function of the nature of R-group was accomplished. The initial set of linear alkyl R-group of different length (R=(CH2 )n CH3 , n = 0-9) was augmented by groups which form stable organic cations, such as tert-butyl, isopropyl, allyl, and phenyl. Investigation of relative stability (with bonding energy as the measure) was accompanied by detailed study of changes in aromaticity using a large set of descriptors, as well as by the evaluation of energetics of possible migration of R-group from the hub-site to the spoke-position. Decrease in stability of functionalized corannulene cations with lengthening of R-group and/or replacing it with branched alkyl group was found to be the general trend. At the same time, π-conjugated groups such as allyl or phenyl ones, stabilize the system. All methods/approaches applied unambiguously indicated that the actual stability of the hub-functionalized corannulene cations is indeed a multi faceted phenomenon. Important contributions come from different interplay between attractive (ΔEorb vs. ΔEelstat ) and repulsive (ΔEPauli ) components of the bonding, from changes in aromatic behavior of rings in polyaromatic fragment, and from activation barrier for the process of migration of R-group. © 2016 Wiley Periodicals, Inc.