UC Berkeley

The synthesis and characterization of several lanthanide single molecule magnets and a relatedseries of benzene bridged lanthanide compounds are described in this dissertation. Previously over- looked ligand types, namely metalloligands and borole dianions, are shown to improve the oper- ating temperature of lanthanide single molecule magnets by slowing thermally independent relax- ation. This dissertation also touches upon a rare example of a highly covalent lanthanide arene interaction in a series of lanthanide benzene inverse sandwich compounds. Chapter 1 introduces single molecule magnetism and provides relevant background infor- mation regarding their electronic structure. The figures of merit used to evaluate the performance of different compounds are defined and important milestones in the field are discussed. Chapter 2 describes the synthesis and characterization of a series of tetrathiotungstate bridged lanthanide complexes. The magnetic characterization of these compounds and their comparison with isostructural tetrathiomolybdate complexes reveals that relativistic effects impact the mag- netic exchange interaction between the bridge electron and the adjacent lanthanides. Chapter 3 details the synthesis and characterization of a series of cobalt bis-(1,2-diphenyl- dithiolate) bridged lanthanide complexes as well as their post synthetic reduction. The dysprosium congener of this complex exhibited single molecule magnetism with suppressed temperature inde- pendent relaxation. Chapter 4 describes the synthesis and characterization of a dysprosium bis-borolide single molecule magnet. This compound was found to have an operating temperature of 65 K, which is on par with the best performing dysprosocenium magnets. Computational analysis on the complex showed how substituent modification may be a viable method to increase the blocking temperature of these compounds moving forward. Chapter 5 describes the synthesis and characterization of a series of lanthanide benzene in- verse sandwich compounds. The experimental characterization and computational analysis per- formed suggests that the central benzene is a tetra-anion stabilized by a rare δ bonding interaction with its adjacent lanthanide ions.