Wydział Chemii

Bibek Prajapati

Madan D. Ambhore

Duy-Khoi Dang

Piotr J. Chmielewski

Tadeusz Lis

Carlos J. Gómez-García

Paul M. Zimmerman

Marcin Stępień

2023

Nature Chemistry

15

1541-1548

10.1038/s41557-023-01341-8

Naukowa

Angielski

Artykuł

Electronic and steric efects are known to greatly infuence the structure, characteristics and reactivity of organic compounds. A typical π bond is weakened by oxidation (corresponding to the removal of electrons from bonding orbitals), by reduction (through addition of electrons to antibonding orbitals) and by unpairing of the bonding electrons, such as in the triplet state. Here we describe tetrafuorenofulvalene (TFF), a twisted, open-shell alkene for which these general rules do not hold. Through the synthesis, experimental characterization and computational analysis of its charged species spanning seven redox states, the central alkene bond in TFF is shown to become substantially stronger in the tri- and tetraanion, generated by chemical reduction. Furthermore, although its triplet state contains a weaker alkene bond than the singlet, in the quintet state its bond order increases substantially, yielding a fatter structure. This behaviour originates from the doubly bifurcated topology of the underlying spin system and can be rationalized by the balancing efects of benzenoid aromaticity and spin pairing.

Computational chemistry, Spectrophotometry, Structure elucidation

CC-BY

http://dx.doi.org/10.1038/s41557-023-01341-8