Sterically hindered imidazole ligands are described, along with their synthesis, which are capable of coordinating to Group 2 metals, such as: calcium, magnesium, strontium, in an eta-5 coordination mode which permits the formation of monomeric or dimeric volatile complexes.A compound comprising one or more polysubstituted imidazolate anions coordinated to a metal selected from the group consisting of barium, strontium, magnesium, radium or calcium or mixtures thereof. Alternatively, one anion can be substituted with and a second non-imidazolate anion.Synthesis of the novel compounds and their use to form BST films is also contemplated.