Natural and magnetic optical activity of 2-D chiral cyanido-bridged Mn~Ⅱ-Nb~Ⅳ molecular ferrimagnets

摘要

Unique two dimensional enantiopure cyanido-bridged {[Mn~Ⅱ(R-mpm)_2]_2[Nb~Ⅳ(CN)_8]}4H_2O and {[Mn~Ⅱ(S-mpm)_2]_2[Nb~Ⅳ(CN)_8]}·4H_2O (1-S) (mpm = α-methyt-2-pyridine-methanol) ferrimagnets with T_c = 23.5 K were synthesized and characterized. They reveal natural optical activity (NOA) due to the chiral crystal structure, and magnetic optical activity (MOA) in the presence of an external magnetic field, with the strong enhancement in the magnetically ordered phase below T_c.