A Six–Armed Phenhomazine Ligand with a Potential “Turn–Off” Copper(II) Sensing Capability through Terbium(III) Luminescence Quenching

TRUPP, LEANDRO; BRUTTOMESSO, ANDREA C.; ELISEEVA, SVETLANA V.; PETOUD, STÉPHANE; RAMÍREZ, JAVIER A.; BARJA, BEATRIZ CARMEN

CHEMISTRY-A EUROPEAN JOURNAL

WILEY-V C H VERLAG GMBH

Año: 2020

0947-6539

Abstract: Herein we describe the design, synthesis andcharacterization of a phenhomazine ligand with six pendant acetatearms designed for the combined coordination of copper(II) andlanthanide(III) ions, with the perspective of the development of a?turn?off? copper sensor. The key step for the ligand preparation wasthe one?step endomethylene bridge fission of a diamino Tröger?sbase with a concomitant alkylation. Fluorescence and absorptionspectroscopies as well as nuclear magnetic resonance (NMR)experiments were performed in order to analyze and understand thecoordination properties of the ligand. Transition metal coordinationwas driven by the synergistic effect of the free nitrogen atoms of thediazocinic core and the two central acetate arms attached to thosenitrogens, whereas lanthanide coordination is performed by externalacetate arms, presumably forming a self?assembled 2:2metallosupramolecular structure. The terbium complex shows thetypical green emission with narrow bands and long luminescencelifetimes. The luminescence quenching produced by the presence ofcopper(II) ions was analyzed. This work sets therefore a starting pointfor the development of a phenhomazine?based ?turn?off? copper(II)sensor.