Tautocrowns: a concept for a sensing molecule with an active side-arm

• Published in: Tetrahedron Vol. 66; no. 24; pp. 4292 - 4297
• Main Authors: Antonov, Liudmil M., Kurteva, Vanya B., Simeonov, Svilen P., Deneva, Vera V., Crochet, Aurelien, Fromm, Katharina M.
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 12.06.2010; Elsevier
• Subjects: Active side-arm; Alkali metals; Alkaline earth metals; Aza-crown; Chemistry; Chemistry, Organic; Condensed benzenic and aromatic compounds; Coordination compounds; Exact sciences and technology; Heterocyclic compounds; Heterocyclic compounds with n hetero atom and also o and/or s, se, te hetero atoms; Heterocyclic compounds with o, s, se, te hetero atom and condensed derivatives; Inorganic chemistry and origins of life; Molecular switches; Organic chemistry; Physical Sciences; Preparations and properties; Proton transfer; Science & Technology; Tautomerism; X-ray; Alkaline earth metals; Molecular switches; YMHNVFJLDCCYAF-IRWWKPKRSA-N; Alkali metals; Active side-arm; Proton transfer; Tautomerism; WBZGIQOMBHDMTD-XWNIEBHWSA-N; X-ray; Aza-crown; CROWN; DESIGN; SELECTIVE FLUORESCENT CHEMOSENSOR; DRIVEN; SENSORS; AZACROWN; SCHIFF-BASES; CHEMISTRY; CATION; Nitrogen heterocycle; Ligand; Enol; Metal ion; Crown compound; Molecular interaction; Alkaline earth metal; Oxygen heterocycle; Macrocycle; Azo compound; Aromatic compound; Selector switch; Chemical synthesis; Biological receptor; Complexation; Nitrogen crown compound; Measurement sensor; Alkali metal; Tautomer; Ketone; X ray diffraction; Naphthalene derivatives; Absorption spectrometry; Molecular electronics; Bathochromism; Inclusion compound; Hydrogen bond
• ISSN: 0040-4020; 1464-5416
• DOI: 10.1016/j.tet.2010.04.049

A new sensing molecule containing aza-15-crown-5 as a receptor and 4-(phenyldiazenyl)naphthalen-1-ol as a signal converter has been synthesized. In the free ligand, the hydrogen bonding between the tautomeric OH group and the nitrogen atom from the macrocycle fully shifts the tautomeric equilibrium towards the enol form. The complexation reverses the equilibrium as a result of the strong interaction between the metal ion captured in the macrocyclic moiety and the tautomeric carbonyl group. The complex formation is accompanied by strong bathochromic (between 60 and 100 nm) and hyperchromic effects on the absorption spectra. Obviously, the tautomeric OH/C O groups play the role of an active side-arm in the complexation, supporting it via formation of a 3D cavity and giving possibility for ejection of the guest compound under stimuli to shift the tautomeric process back. [Display omitted]