Development of Synthetic Methods for Novel Photofunctional Multinuclear Complexes: Simple Synthetic Methods for Multinuclear Complexes Using Various C-C Coupling Reactions

Description

This book presents several helpful synthetic methods for diverse multinuclear complexes. The results described can be used to selectively connect mononuclear as well as multinuclear complexes with other metal complexes to construct valuable photofunctional compounds. Using the new synthetic methods, it was possible to selectively connect several types of metal complexes in a single step under relatively mild reaction conditions. This so-called building block approach utilizes various C–C coupling reactions between metal complexes with functional groups as active moieties. Owing to the large pi-conjugation systems, the multinuclear complexes synthesized using coupling reactions showed a strong absorption ability over a wide range of visible light and long emission lifetimes, which are ideal properties for photosensitizers and light absorbers. By combining these coupling methods with the newly developed hydrogenation reactions, the binding mode of the linkers in multinuclear complexes can be modified in order to tune the photophysical properties and photocatalytic ability. As such, the synthesized multinuclear complexes can be used for various purposes, e.g., as photocatalysts and photosensitizers, and in light-harvesting systems. The synthetic methods and strategies presented in this book diversify not only the structures but also functions of multinuclear complexes. Supervisor’s Foreword List of Published Articles Acknowledgements Contents 1 General Introduction 1.1 Background 1.2 Overview of this Thesis References 2 Synthesis of Multinuclear Complexes Using the Mizoroki–Heck Reaction 2.1 Introduction 2.2 Results and Discussion 2.2.1 Synthesis of a Re(I) Dinuclear Complex Using the Mizoroki–Heck Reaction 2.2.2 Synthesis of Various Trinuclear Complexes Using the Mizoroki–Heck Reaction 2.2.3 Photophysical Properties and Photocatalytic Abilities of the Trinuclear Complexes 2.3 Conclusions 2.4 Experimental 2.4.1 General Procedures 2.4.2 Emission Measurements 2.4.3 Photocatalytic Reactions 2.4.4 Materials 2.4.5 Synthesis References 3 Selective Synthesis of Various Photofunctional Multinuclear Complexes Using a Combination of the Mizoroki–Heck Reaction and the Homo-coupling Reaction 3.1 Introduction 3.2 Results and Discussion 3.2.1 The Effect of Air on the Mizoroki–Heck Reaction 3.2.2 Concentration Effect of Phosphine Ligands on the Reaction Abilities of the Mizoroki–Heck Reaction 3.2.3 Investigation of the Byproducts Observed During the Mizoroki–Heck Reaction in the Absence of Phosphine Ligands 3.2.4 Confirmation of the Side Reaction: Selective Homo-coupling Reactions 3.2.5 Particle Size Measurements of Pd Compounds During the Mizoroki–Heck Reaction 3.2.6 Improvement of the Homo-coupling Reaction Using Metal Indium as an Electron Donor 3.2.7 Strategies for Selective Mizoroki–Heck Reactions and Homo-coupling Reactions 3.2.8 Synthesis of Novel Multinuclear Complexes Using a Combination of the Mizoroki–Heck Reaction and the Homo-coupling Reaction 3.2.9 Photophysical Properties of OsReRu 3.3 Conclusions 3.4 Experimental 3.4.1 Materials 3.4.2 Synthesis References 4 Photochemical and Electrochemical Hydrogenation of π-Conjugated Bridging Ligands on Photofunctional Multinuclear Complexes 4.1 Introduction 4.2 Results and Discussion 4.2.1 Photochemical Hydrogenation of a Vinylene Linker in a Bridging Ligand on a Ru-Re Dinuclear Complex Synthesized by Using the Mizoroki–Heck Reaction 4.2.2 Purification of the Products of Photochemical Hydrogenation of Ru = Re and Identification Using ESI-TOF–MS 4.2.3 Photochemical Hydrogenation with Different Solvents 4.2.4 Photochemical Hydrogenation of Various Dinuclear Complexes with a Vinylene Linker Synthesized by Using the Mizoroki–Heck Reaction 4.2.5 Photochemical Hydrogenation of Dinuclear Complexes Synthesized by Using Olefin Metathesis and Sonogashira Coupling 4.2.6 Photochemical Hydrogenation with Different Wavelength Irradiation Light 4.2.7 Electrochemical Hydrogenation of the Ru-Re Dinuclear Complex with a Vinylene Linker 4.2.8 Photocatalytic Ability of Ru-Re-Ru for CO2 Reduction 4.2.9 Development of an Efficient Photocatalyst by Using Both Stepwise Mizoroki–Heck Reactions and the Photochemical Hydrogenation Reaction 4.3 Conclusion 4.4 Experimental 4.4.1 Electrochemical Reactions References 5 Synthesis of Novel Multinuclear Complexes for Light-Harvesting Systems Using the Coupling Reactions with Ring-Shaped Multinuclear Re(I) Complexes as Building Blocks 5.1 Introduction 5.2 Results and Discussion 5.2.1 Decarbonylation Reactions Using Me3NO 5.2.2 Synthesis of Ring-Shaped Multinuclear Re(I) Complexes Possessing Bromo Groups 5.2.3 Coupling Reactions Using Re(I) Rings Possessing Bromo Groups as Starting Materials 5.2.4 Photophysical Properties and Light-Harvesting Abilities of Ring-Ru and Ring-Ring 5.3 Conclusions 5.4 Experimental References 6 Conclusions Curriculum Vitae