ORGN 362

Calcium ions, which act as second messengers, are released inside certain cells as an oscillatory signal. This signal is associated with a variety of important physiological processes such as hormone secretion.  To study their effects on cells and proteins, a molecule that will mimic these oscillations has been designed. An unsubstituted bis-spiropyran is known to be photochromic. Addition of substituted amines (R₁=H; R₂=CH₂CO₂^-) creates a binding site for Ca²⁺, which is expected to be reversibly disrupted upon irradiation. Compound (1) with R₁=CH₃ and R₂=CH₂CO₂^- was found to bind Ca²⁺ moderately and selectively over Mg²⁺, and is not photochromic.  A variation of compound 1 (R₁=CH₃, R₂=CH₂CH₂CO₂^-) will be synthesized in order to examine the effects of ligand environment on the binding strength and selectivity. The results of binding M²⁺ ions to this chelator will be presented.