No abstract

New tetrazines substituted by heteroatoms have been synthesized and their electrochemical and photochemical properties investigated. All compounds are reversibly electroactive with standard potentials shifting cathodically according to the donor character of the substituent. The tetrazine derivatives are also fluorescent with maximum emission wavelengths in the range 550-575 nm. Some of them show very long fluorescence lifetimes (several tens of ns) and remain fluorescent in the solid state without major changes in the spectral features. The fluorescence of one of the derivatives can be efficiently quenched by the presence of electron-rich compounds such as triphenylamines, phenol or anisole, which make them very promising compounds for sensor applications.

New fluorescent tetrazines have been prepared and their electrochemistry and fluorescence efficiency evaluated. The occurrence of fluorescence as well as the wavelength were found to be strongly dependent on the substituents, which have to be electronegative heteroatoms. This has been rationalized through a computational study that showed that the crucial factor is the nature of the HOMO, which determines the existence or not of fluorescence. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Several new supramolecular s-tetrazines have been prepared and studied. Their electrochemical and spectroscopic properties have been investigated, especially in the presence of quenchers. Fluorescence quenching has been shown to occur as expected through a charge transfer mechanism and the cyclophane structure has been shown to lead to an acceleration of the quenching process.Scheme 1 Formula of the s-tetrazines.