Synthesis And Properties Of Functional Complexes Based On Tetrathiafulvalene Ligands

Tetrathiafulvalene (TTF) and its derivatives have been widely used as versatile building blocks in the fields of supramolecular and material chemistry due to its high π-electron donor ability and multiple and reversible redox processes. One of the research trends in novel functional materials is to search for molecules with more π-extended systems. Intensive studies have shown that the extension of TTF units not only leads to stabilize oxidized states but also can enhance the dimensionality of materials by increased π…π or S…S interactions between planes. In this dissertation, we report the synthesis of a series of new coordination polymers based on the redox-active tetrathiafulvalene-tetrapyridyl ligand. Moreover, the photophysical and electrochemical properties of these compounds are systematically studied.1. Synthesis and properties of electroactive coordination polymers based on the Tetra(4-pyridyl)-tetrathiafulvalene ligandSeven new coordination polymers based on the redox-active tetra(4-pyridyl)-tetrathiafulvalene ligand (TTF(py)4) and different transition-metal ions were synthesized and characterized. The tetrapyridyl ligand coordinates to metal ions in a bidentate or tetradentate fashion, forming complexes 1-7 with different structures. Complex 1 exhibits a one-dimensional chain structure. Complexes 2,3, and 4 possess similar (4,2)-connected binodal two-dimensional networks, while complexes 5 and 6 have similar (4,4)-connected binodal two-dimensional networks with two different rings. Complex 7 shows a 2-fold interpenetrated (4,4)-connected binodal PtS-type three-dimensional framework. Meanwhile, these complexes feature diverse nonclassical hydrogen bonding interactions. In addition, magnetic and solid-state electrochemical properties for typical complexes have been studied. These results suggest that the incorporation of redox-active ligands into coordination frameworks is an effective strategy to engineer porosity and redox activity into framework systems2. Synthesis and properties of spin crossover iron(Ⅱ) metal-organic frameworks containing tetra(4-pyridyl)-tetrathiafulvalene ligand.Two three-dimensional (3D) Fe(Ⅱ) metal-organic frameworks (MOFs), based on the redox-active tetra(4-pyridyl)-tetrathiafulvalene ligand (TTF(py)4) were synthesized and structurally characterized. Complex 1 has a 2-fold interpenetrated (4,6)-connected binodal sqc173-type 3D framework, while complex 2 shows a (4,6)-connected binodal sqcll-type 3D framework. Their solid-state electrochemical and magnetic properties were investigated. Both of them show the redox activity of the TTF moiety. Antiferromagnetic interaction is observed in complex 1. Complex 2 presents an incomplete gradual spin crossover (SCO) behavior, representing the rare example of SCO MOFs based on the TTF ligand. Importantly, doping iodine into the MOFs not only can improve the conductive property but also can change the magnetic properties significantly.