engleski

Supramolecular interactions in 1, n´-disubstituted ferrocene oligoamides

Ferrocenes substituted with chiral amino acids at both cyclopentadienyl rings show very interesting supramolecular interactions between the two substituents.1 These 1, n´-disubstituted ferrocenes have served as inspiration for selective catalysts and supramolecular systems.2, 3 Recently we discovered that if compared to previous systems, a formal isomerization of one amide bond can yield very selective supramolecular catalysts.4 Herein, we present the synthesis and characterization of 1, n´-disubstituted ferrocenes 2 bearing pedant trans-1S, 2S-cyclohexanediamines instead of amino acids, Figure 1 (left). The corresponding mono-substituted analogues 1 have been prepared for comparison. In particular, all compounds have been studied using NMR, IR, UV-Vis and CD spectroscopy, as well as mass spectrometry. In addition, the structural features have also been elucidated from several determined x-ray single crystal structures (including 2a) and DFT calculations. It is interesting to mention that 2a reveals significantly different CD spectra in dichloromethane and methanol, Figure 1 (right), indicating a major change in supramolecular organization in solution. References 1 Kirin, S. I. ; Kraatz, H.-B. ; Metzler-Nolte, N. Chem. Soc. Rev. 2006, 35, 348-354. 2 Kokan, Z. ; Glasovac, Z. ; Majerić Elenkov, M. ; Gredičak, M. ; Jerić, I. ; Kirin, S. I. Organometallics 2014, 33, 4005-4015. 3 Kokan, Z. ; Kovačević, B. ; Štefanić, Z. ; Tzvetkova ; P. ; Kirin, S. I. Chem. Commun. 2018, 54, 2094-2097. 4 Opačak, S. ; Kokan, Z. ; Glasovac, Z. ; Perić, B. ; Kirin, S. I. Eur. J. Org. Chem. 2019, in press. doi: 10.1002/ejoc.201801647

amino acids ; ferrocene ; supramolecular

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