Publication details

Unexpected structural distribution of electroactive ortho-Iminoboronate in protic and aprotic solvents determined using MS

Authors

KONHEFR Martin LACINA Karel SKRUTKOVÁ LANGMAJEROVÁ Monika GLATZ Zdeněk SKLÁDAL Petr MAZAL Ctibor

Year of publication 2017
Type Conference abstract
Citation
Description As metal cations are essential not only in biology, their selective sensing is important also from an industrial and environmental viewpoint. These diverse applications have lead to the development of many molecular sensor systems for cationic guest species. A wide variety of e. g. macrocycles with ferrocene unit as redox signaling group have been synthesized [1]. Generally, complexation by these ligands (cations) affects the electrochemistry of the redox center, particularly when the guest molecule is either in close proximity to the iron atom or coordinated by functional groups that are conjugated with the ferrocene system. This configuration is observable in the aminoferrocene derivatives. As we studied the structure of novel iminoboronates bearing ferrocene as a signaling group for electrochemical sensing intended for a saccharide recognition [2], we realized that ortho-positioned iminoboronate in MS formed stable sodium and potassium chelates. These complexation properties were observed only in a protic solvent (methanol). None complexes were detected in an aprotic solvent (acetonitrile). Thus, methanol–hydroxyle rearrangement on boron atom in the proximity of imino group plays the most important role in the forming of an ideal surrounding (host) around complexed cation (guest) to form the chelate. In addition, this interacting site is close to redox-active center of ferrocene which reports on the binding event. Contrary to the protic solvent, stable ortho-iminoboronate anhydrides were observed in the aprotic solvent without any tendency to form chelates with cations.
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