Peroxido-bridged chiral double-decker dysprosium macrocycles.

ABSTRACT

Lanthanide peroxides show high reactivity in oxidative coupling of methane (OCM). However, the number of isolated and structurally characterized molecular species remains relatively small. To the best of our knowledge, homochiral molecule-based lanthanide peroxides have not been reported. Herein, two pairs of side-on peroxido-bridged dinuclear hexaazamacrocyclic dysprosium enantiomers with formulas [Dy2(LES/R)2L2O2](BPh4)2·CH3OH·CH3CN (where LE is derived from the condensation reaction between (1S,2S)/(1R,2R)-1,2-diphenylethylenediamine and 2,6-diformylpyridine; HL = 2,6-diphenylphenol) (1/2) and [Dy2(LES/R)2Cl2O2](BPh4)2·2CH3CN (3/4) are specially designed and created with the help of hydrogen peroxide. The out-of-phase alternating-current magnetic susceptibility of 1/2 gives rise to frequency-dependent peaks between 6 and 32 K under a zero applied direct current (dc) field, while no peak at any temperature and frequency was observed for 3/4 implying the presence of a weak axial crystal field (CF).