title: Reversible mutarotation in a macrocyclic ytterbium complex.
abstract: M40 is a four-fold symmetry macrocyclic ligand endowed with axial and central chiral elements, all of R configuration. It promptly binds late lanthanides (Yb(III) and Lu(III) ) yielding a negative helicity, as witnessed by NIR-electronic circular dichroism. In the course of a few hours, a new conformation of the complex takes over, which has opposite helicity and allows for a dynamic free-bound equilibrium. Upon slow solvent evaporation, the original conformation is retrieved and the whole dynamic process can be started again, as in a sandclock, allowing one to envisage applications as a time-marker chiral switch.
authors.affiliation: Dipartimento Scienze Chimiche, University of Catania viale A. Doria 6, 95125 Catania, Italy.
authors.forename: Francesco P
authors.initials: FP
authors.lastname: Ballistreri
authors.forename: Salvatore
authors.initials: S
authors.lastname: Gentile
authors.forename: Andrea
authors.initials: A
authors.lastname: Pappalardo
authors.forename: Gaetano A
authors.initials: GA
authors.lastname: Tomaselli
authors.forename: Sanghamitra
authors.initials: S
authors.lastname: Pradhan
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Di Bari