New developments in the cyclopentadienyl chemistry of the alkaline-earth metals

Recent developments in the chemistry of cyclopentadienyl derivatives of the alkaline-earth (group 2) metals are reviewed. New complexes and their applications in organometallic and materials synthesis reflect the growing number of ways that can be used to manipulate the alkaline-earth-cyclopentadienyl bond. Complementing the experimental work are computational studies using density functional theory methods. These can now reproduce the geometries of many group 2 molecules with encouraging accuracy and have provided new insight into the energetics of metal-ring bonding. The progress made in group 2 cyclopentadienyl chemistry in the past decade indicates that more expansion can be expected.