Dynamics of ion-regulated photoinduced electron transfer in BODIPY-BAPTA conjugates.

نویسندگان

  • Pinar Batat
  • Guillaume Vives
  • Robin Bofinger
  • Ren-Wei Chang
  • Brice Kauffmann
  • Reiko Oda
  • Gediminas Jonusauskas
  • Nathan D McClenaghan
چکیده

Efficient Ca(2+)-switched fluorescent sensors, where fluorescence output is governed by a light-activated ion-gated electron transfer pathway, can be obtained on combining BODIPY chromophores with a readily oxidized biocompatible and selective BAPTA receptor. Herein we report the synthesis and studies of two such conjugates, which vary in the nature of the spacer separating the two electroactive components, namely none (1) or phenyl (2). Single crystal X-ray crystallography and molecular modelling structures and calculations give information on molecular and electronic structure, while steady-state fluorescence experiments show high Ca(2+)-induced fluorescence enhancement factors of 122 and 23 and K(d) values of 0.50 μM and 0.13 μM for 1 and 2, respectively. Notably, studies of the ultrafast photoinduced processes (through transient absorption spectroscopy) give access to electron transfer dynamics in pseudo-physiological media as well as in a polar non-protic solvent and information about the fate of the excited molecules in the presence and absence of calcium. In water, electron transfer rates as high as 3.3 × 10(12) s(−1) and 8.3 × 10(11) s(−1) are measured for the ion-free, directly connected conjugate and the variant incorporating a phenyl spacer, respectively. This electron transfer pathway is efficiently blocked by the presence of an ion, restoring fluorescence.

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عنوان ژورنال:
  • Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology

دوره 11 11  شماره 

صفحات  -

تاریخ انتشار 2012