Supervisor's Foreword; Parts of this thesis have been published in the following journal articles:; Acknowledgements; Contents; 1 Introduction; Abstract; 1.1 Molecule-Based Magnet; 1.2 Molecular Field Theory; 1.3 Van Vleck Paramagnetism; 1.4 Cyanido-Bridged Metal Assemblies and Their Functionalities; 1.5 Octacyanidometalate-Based Magnets; 1.6 Photo-Induced Magnetization in Cyanido-Bridged Metal Assemblies; 1.7 Spin-Crossover Phenomenon; 1.8 Light-Induced Excited Spin State Trapping (LIESST); 1.9 Ionic Conductivity; 1.10 Objectives of This Work; References

2 Observation of Light-Induced Spin-Crossover Magnetism in a Fe-[Nb(CN)8] Bimetal AssemblyAbstract; 2.1 Introduction; 2.2 Experiments; 2.2.1 Synthesis; 2.2.2 Characterization; 2.2.3 Photo-Irradiation Measurements; 2.3 Results; 2.3.1 Elemental Analysis; 2.3.2 XRD Patterns and Crystal Structure; 2.3.3 IR Spectra; 2.3.4 Magnetic Properties; 2.3.5 UV-Vis Spectra; 2.3.6 57Fe Mössbauer Spectra; 2.3.7 Photomagnetic Measurements; 2.3.8 UV-Vis Spectra Under the Light Irradiation; 2.4 Discussion; 2.4.1 Electronic States of High-T and Low-T Forms; 2.4.2 XRD Patterns and Crystal Structure

2.4.3 Magnetic Properties of Low-T Form2.4.4 Photomagnetic Properties; 2.5 Conclusion; References; 3 Two-Step Spin-Crossover and Photo-Induced Spin-Crossover Ferromagnetism in Fe2II[NbIV(CN)8](4-Methylpyridine)8 · 2H2O; Abstract; 3.1 Introduction; 3.2 Experiments; 3.2.1 Synthesis; 3.2.2 Characterization; 3.2.3 Photo-Irradiation Measurements; 3.3 Results; 3.3.1 Elemental Analysis; 3.3.2 Single Crystal X-Ray Analysis at Various Temperatures; 3.3.3 IR Spectra; 3.3.4 Magnetic Properties; 3.3.5 Temperature Dependence of UV-Vis Spectra; 3.3.6 Photomagnetic Measurements

3.3.7 UV-Vis Spectra Under the Light Irradiation at 3 K3.4 Discussion; 3.4.1 The Assignment of Spin-Transition in the Present System; 3.4.2 The Analysis of Magnetic Susceptibility and the Electronic State; 3.4.3 Temperature Dependence of Crystal Structure; 3.4.4 Thermodynamical Properties; 3.4.5 Magnetic Properties of Low Temperature State; 3.4.6 Photomagnetic Properties; 3.5 Conclusion; References; 4 Observation of Coexistence of Super-Ionic Conductivity and Metamagnetism in Mn3[NbIV (CN)8]2(4-Aminopyridine)10 (4-Aminopyridinium)2 · 12H2O; Abstract; 4.1 Introduction; 4.2 Experiments

4.2.1 Synthesis4.2.2 Characterization; 4.2.3 Impedance Measurement; 4.3 Results; 4.3.1 Elemental Analysis; 4.3.2 Single Crystal X-ray Analysis; 4.3.3 Powder X-ray Diffraction Pattern; 4.3.4 IR Spectra; 4.3.5 Magnetic Properties; 4.3.6 Impedance Measurements; 4.4 Discussion; 4.4.1 The Valence State, the Form of Organic Ligand, and the Crystal Structure; 4.4.2 Magnetic Properties; 4.4.3 Conducting Properties; 4.4.4 The Mechanism for Super-Ionic Conductivity; 4.5 Conclusion; References; 5 Concluding Remarks; Abstract; About the Author