1. Chiral Photomagnets Based on Copper(II) complexes of 1,2-Diaminocyclohexane and Octacyanidomolybdate(IV) Ions.
- Author
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Korzeniak T, Sasmal S, Pinkowicz D, Nitek W, Pełka R, Czernia D, Stefańczyk O, and Sieklucka B
- Abstract
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(( R,R )-chxn)
2 ]2 [Mo(CN)8 ]·H2 O ( 1R ) and [Cu(( S,S )-chxn)2 ]2 [Mo(CN)8 ]·H2 O ( 1S ) 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 1R , 1S , and 1rac result from the blue light excitation (436 nm) of the photomagnetically active octacyanidomolybdate(IV) ions. In the excited state MoIV HS centers with S = 1 couple antiferromagnetically with the neighboring CuII centers with JCuMo values of -1.3, -1.0, and -1.1 cm-1 for 1R , 1S , and 1rac , respectively. The values of thermal relaxation energy barriers have been estimated as 142 and 356 K for 1R and 1S , being comparable with the energy range of the thermal bath. The value for 1rac reveals a significantly lower value of 75 K. On the basis of these results the value of gMo HS has been estimated to be in the range 4.8-5.8.- Published
- 2020
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