Wydział Chemii

Katarzyna Wolska

Jan Janczak

Paula Gawryszewska

Jerzy Lisowski

2021

Polyhedron

198

115057/1-115057/12

10.1016/j.poly.2021.115057

Naukowa

Angielski

Artykuł

A step-by-step synthesis based on the application of monoprotected 2.6-diformylpyridine intermediate resulted in the formation of enantiopure Eu(III), Yb(III) and Y(III) complexes of unsymmetrical macrocycles L³ and L⁴ containing two pyridine units and two different diamine and diimine links. The final step in the formation of these mixed amine-imine hexaazamacrocycles was based on a templated condensation of ethylenediamine or enantiopure trans-1,2-diaminocyclohexane with a linear [2 + 1] amine intermediate bearing two pyridinecarboxaldehyde fragments. The identity of these unsymmetrical complexes have been determined on the basis of 2D NMR and ESI MS spectroscopy and confirmed by the X-ray crystal structures of Eu(III) and Yb(III) complexes of macrocycle L³. In these complexes the macrocyclic ligand adopts twist-fold conformation and the twist of the achiral ethylene link is dictated by the conformation of the cyclohexane link. The ten-coordinate Ln(III) ions are bound in equatorial positions by the six nitrogen atoms of the macrocycle and their coordination spheres are completed by two axial bidentate nitrate anions. The luminescent properties of the Eu(III) complexes of L³ and L⁴ have been characterized.

Macrocyclic complexes, Lanthanides, Enantiopure ligands, Crystal structure, Luminescence

http://dx.doi.org/10.1016/j.poly.2021.115057

http://www.elsevier.com