Most industrial processes for producing bulk and fine chemicals are transition metal catalyzed. Toxicity and high cost of platinum group metals are triggering the current search for sustainable catalysts. In this regard, nontoxic and earth-abundant alkali metals could become attractive alternatives. They are the most electropositive elements of the periodic table. With a single s electron in the valence shell and a low ionization enthalpy they easily form M+ ions. The vacant, low-energy orbital of the M+ ion is capable of accepting an electron pair. This Lewis acidic property can be utilized in molecular catalysis. Since alkali metal compounds easily dimerize, oligomerize or even polymerize (Scheme A.1-1), suitable ligands are crucial for the isolation of defined metal complexes in their monomeric form.