Isolation, Reactivity, and Tunable Properties of a Strained Antiaromatic Osmacycle

Li，Qian1; Hua，Yuhui2; Tang，Chun1; Chen，Dafa2; Luo，Ming2; Xia，Haiping1,2

2023-04-05

10.1021/jacs.3c00942

Journal of the American Chemical Society   Impact Factor & Quartile

0002-7863

1520-5126

Strain and antiaromaticity in compounds are recognized as two substantial destabilizing features, and consequently, realization of dual destabilizing features in a single molecule is challenging and far more difficult in a single ring. Moreover, transformation of an antiaromatic framework to different antiaromatic or aromatic species is a significant subject in antiaromatic chemistry and has attracted increasing interest. In this work, we isolated a highly strained antiaromatic metallacycle in which a cyclic metal vinylidene unit is embedded. Computational studies revealed its ring strain energies and antiaromatic character and showed that the metal incorporation and the phosphonium substituents play a crucial role in its stabilization. The mechanism of its formation has been illustrated by density functional theory (DFT) calculations and the isolation of a key intermediate. We further discovered diverse reactivities and structural reshuffling of this unusual strained antiaromatic complex according to its two destabilizing characters. We obtained two isomers of metallaindenes fused with oxiranes from the direct oxidation of the metal vinylidene or by nucleophilic addition to an isolated metallacyclocumulene formed by the reaction of metal vinylidene with hydroxide ion, achieving a reconfiguration of the antiaromatic framework. Transformations of the antiaromatic metallacycle by electrophiles to various aromatic metallaindynes have been achieved, and that a condensed Fukui function was employed to confirm the regioselectivity of the electrophilic additions, and the acid/base-induced aromaticity switch along with tunable photophysical properties were investigated. These interesting transformations not only enrich the chemistry of metal vinylidenes and antiaromatics and could also perform potentially as switchable optical materials.

English

NI Journal Papers

Corresponding

2-s2.0-85151157843

Scopus

1.State Key Laboratory of Physical Chemistry of Solid Surfaces,Collaborative Innovation Center of Chemistry for Energy Materials (iChEM),College of Chemistry and Chemical Engineering,Xiamen University,Xiamen,361005,China
2.Shenzhen Grubbs Institute,Department of Chemistry,Southern University of Science and Technology,Shenzhen,518055,China

Li，Qian,Hua，Yuhui,Tang，Chun,et al. Isolation, Reactivity, and Tunable Properties of a Strained Antiaromatic Osmacycle[J]. Journal of the American Chemical Society,2023,145(13):7580-7591.

Li，Qian,Hua，Yuhui,Tang，Chun,Chen，Dafa,Luo，Ming,&Xia，Haiping.(2023).Isolation, Reactivity, and Tunable Properties of a Strained Antiaromatic Osmacycle.Journal of the American Chemical Society,145(13),7580-7591.

Li，Qian,et al."Isolation, Reactivity, and Tunable Properties of a Strained Antiaromatic Osmacycle".Journal of the American Chemical Society 145.13(2023):7580-7591.