Host-guest interaction of rotaxane assembly through selective detection of ferric ion: Insight into hemin sensing and switching with sodium ascorbate.

A mechanically interlocked host rotaxane was synthesized by incorporation of tetraphenylethylene and phenanthroimidazole units in the axle to exhibit significant emission bands and demonstrate host-guest interactions via its topologically constrained cavity, and thus to induce a significant and selective fluorescence quenching of rotaxane towards ferric ion (Fe 3+ ). The quenching efficiencies of rotaxane with both ferric ion (Fe 3+ ) and bio-molecular Hemin (containing ferric ion) were investigated to compare the sensitivities of rotaxane for ferric ion and bio-molecular Hemin. The present study could probe host-guest interactions of rotaxane with ferric ion (Fe 3+ ) and Hemin as well as monitoring the biological conversion of Hemin to Heme in presence of sodium ascorbate (as a reducing agent), where the reduced non-toxic Heme could be generated from the toxic form of Hemin. [ABSTRACT FROM AUTHOR]