Chiral Photomagnets Based on Copper(II) Complexes of 1,2-Diaminocyclohexane and Octacyanidomolybdate(IV) Ions

Chiral photomagnets compose a class of multifunctional molecule-based materials with light-induced alteration of magnetization and chiral properties. The rational design and synthesis of such assemblies is a challenge, and only few such systems are known. Herein, the remarkable octacyanide-bridged enantiomeric pair of 1-D chains [Cu(()-chxn)][Mo(CN)]·HO () and [Cu(()-chxn)][Mo(CN)]·HO () exhibiting enantiopure structural helicity, which results in optical activity in the 350-800 nm range as confirmed by natural circular dichroism (NCD) spectra, is reported. The photomagnetic effects of , , and result from the blue light excitation (436 nm) of the photomagnetically active octacyanidomolybdate(IV) ions. In the excited state Mo centers with = 1 couple antiferromagnetically with the neighboring Cu centers with values of -1.3, -1.0, and -1.1 cm for , , and , respectively. The values of thermal relaxation energy barriers have been estimated as 142 and 356 K for and , being comparable with the energy range of the thermal bath. The value for reveals a significantly lower value of 75 K. On the basis of these results the value of has been estimated to be in the range 4.8-5.8.