Porous Mn 2+ Magnet with a Pt-Cl Framework: Correlation between Water Vapor Adsorption/Desorption and Slow Magnetic Relaxation.

We report the water adsorption/desorption behavior and dynamic magnetic properties of the Pt-Cl chain complex [{[Pt(en) 2 ][PtCl 2 (en) 2 ]} 3 ][{(MnCl 5 )Cl 3 } 2 ] ⋅ 12H 2 O (1). Upon heating 1 in a vacuum, we obtained the dehydrated form [{[Pt(en) 2 ][PtCl 2 (en) 2 ]} 3 ][{(MnCl 5 )Cl 3 } 2 ] (1DH). The framework structures of 1 and 1DH are identical, and both complexes underwent slow magnetic relaxation. However, the magnetic relaxation times for 1DH were shorter than those for 1, meaning that the dynamic magnetic properties were controlled upon water vapor adsorption/desorption. From detailed analyses of the dynamic magnetic behavior, a phonon-bottleneck effect contributes to the magnetic relaxation processes. We discuss the mechanism for the changes in the magnetic relaxation processes upon dehydration in terms of the heat capacity and thermal conductivity.