Juin 2019. Publication de Frédéric Gohier

 

Syntheses and NMR and XRD studies of carbohydrate–ferrocene conjugates

 (Fanny Peigneguy, Magali Allain, Charles Cougnon, Pierre Frère, Benjamin Siegler, Christine Bressy  and Frédéric Gohier)

Ferrocenes are entities that have attracted a lot of interest since their appearance in the middle of the 20th century. They are present in a wide range of applications integrated in miscellaneous structures involving an important investment in their design and synthesis.

Ferrocenes have been associated with carbohydrates to target biological activities and molecular recognition or as redox detectors. They can be synthesized via side chains
containing triazole, amide, carboxylate, boronate, and thioethermoieties. Transacetalisation is another way to link ferrocenes and carbohydrates.

The structures obtained can be complex and the NMR tool can be very valuable in elucidating certain conformations. Studies on the free rotation of cyclopentadienyl
rings around the Cp–Fe–cp axis have attracted attention and depending on substitution, eclipsed and staggered conformations are stable. NMR spectroscopic studies usually show that alpha and beta hydrogens are equivalent and that their chemical shifts depend on the substituent as shown for chalcones linked to ferrocenes.

Longitudinal relaxation times of the carbons of substituted cyclopentadienyl have also been measured.

 


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