Central-to-Helical-to-Axial Chirality Transfer in Chiroptical Sensing with Ferrocene Chromophore.

Autor: Nuskol, Marko, Šutalo, Petar, Kovačević, Monika, Kodrin, Ivan, Čakić Semenčić, Mojca
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Zdroj: Inorganics; Jun2023, Vol. 11 Issue 6, p225, 12p
Abstrakt: The effect of attaching the achiral, cyclic 1-aminocyclohexanecarboxylic acid (Ac6c) directly to the aminoferrocene unit (Ac6c−NH−Fc) appears to be a promising route for the development of a new chiroptical sensor based on a ferrocene chromophore. Three new compounds (Boc−AA−Ac6c−NH−Fc; AA = L-Ala, L-Val, L-Phe) were synthesized, spectroscopically characterized (IR, NMR, CD), and conformationally analyzed (DFT). The chiral information was transferred from the L-amino acid to the ferrocene chromophore by the predominant formation of P-helical structures with ten-membered hydrogen-bonded rings (β-turns). The perturbation of the ferrocene chromophore and the appearance of the negative CD signal near 470 nm originates from a relative orientation of the directly linked amide and cyclopentadienyl planes, described by the dihedral angle χ. The sterically demanding Ac6c amino acid makes trans-like configurations more favorable and thus restricts the dihedral angle χ, which then leads to the appearance of the negative peak near 470 nm in the CD curve. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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