Executive Summary : | Molecular alkaline earth (Ae) chemistry is dominated by magnesium, with heavier congeners like calcium, strontium, and barium complexes being limited due to their large ionic radii and high polarizability. Recently, alkaline earth hydride (Ae-H) complexes have emerged as a new class of reactive compounds, emerging in green catalysts and hydrogen storage materials. Accessing these compounds is challenging due to the requirement of using an extremely bulky ligand, which restricts them to under the Schlenk equilibrium. Until 2007, molecular alkaline earth chemistry was restricted to the +2-oxidation state. Investigation of reduction chemistry led to the isolation of kinetically stable magnesium compounds in the +1 oxidation state, and the library of magnesium (I) compounds reported by using N-N chelating ligands has steadily increased. Recently, the first zero-oxidation-state magnesium system was stabilized using a very bulky ligand with strong reducing abilities. Lighter alkaline earth metals (Be and Mg) have uncovered surprising oxidation state compounds, such as hydrocarbon soluble low oxidation (0 or +1) or Lewis acidic high oxidation (+2) cationic compounds. This project aims to extend the synthesis and library of group (II) halide synthons using N,N,N,P chelating, terphenyl, or other ligand systems, potentially leading to success in the s-block. Designing suitable ligands will continue to evolve main-group chemistry in new dimensions, finding applications in green catalysts and hydrogen storage materials. |