Multifunctional chiral metal hydrogen-bonded organic frameworks constructed from lanthanide ions with trigonal prismatic coordination environment

Abstract

Two pairs of chiral enantiomers D/L-Dy(PMP)3·2H2O (D-1/L-1) and D/L-Yb(PMP)3·2H2O (D-2/L-2) were synthesized by the introduction of enantiomerically pure D/L-PMP (PMP = (phosphonomethyl)proline) ligands into lanthanide coordination chemistry. The chiral characteristic of these products was confirmed by single crystal X-ray diffraction, second harmonic generation (SHG) measurements and circular dichroism (CD) spectra. These complexes are composed of 1D chains constructed from lathanide ions with trigonal prismatic coordination geometry and PMP ligands. The assembly of the 1D chains leaded to the formation of a lanthanide hydrogen-bonded organic frameworks with 1D water chains filled in the channels. Zero-field slow relaxation of magnetization was detected in L-1, whereas L-2 dispays field-induced single-molecule magnet (SMM) behavior. Complexes D-1, L-1 and L-2 show proton conductive ability and their conductivity values reach the order of 10-5 S cm-1 at 90 °C and 98% relative humidity.