Magnetic and Catalytic Properties of Lanthanide Complexes

Lanthanides are an intriguing family of elements possessing unique properties useful in many diverse applications. The first chapter of this work describes the origins of some of these properties and their catalytic and magnetic applications. The second chapter will highlight a highly unusual neodymium catalyst for diene polymerization. This coordination polymer catalyst contains no halides and makes use of no halide donor, yet produces desirable 96% 1,4- cis stereospecific material. The third chapter is concerned with the surprising formation and superparamagnetism of a neodymium-peroxide diimine cluster and the associated crystals. The cluster is formed by a rare example of anion-templated assembly in which the anion is derived from dissolved atmospheric oxygen. The resulting structural motif featured an array of tight three-metal clusters separated by a distance long enough to prevent long-range magnetic order, which resulted in superparamagnetic behavior in the solid state. This is believed to be the first report of superparamagnetism in a bulk crystal state. The fourth and final chapter is concerned with MRI contrast agents and presents an example of a new variety of potential next-generation agents composed of coordination polymers. The gadolinium diethylphosphate polymer features a far longer rotational coordination time than conventional small gadolinium complexes and thus offers dramatically improved T1 relaxation performance at low-fields common in clinical imaging applications. All of these lanthanide complexes are synthesized using an azeotropic distillation method. This method avoids the need for strict water-free techniques and also occasionally allows for novel structures to be obtained, as demonstrated in Chapter 3 in particular.