Coordination Behavior of L‐Glutamic Acid: Spectroscopic and Structural Properties of (L‐Glutamato)(imidazole)copper(II), (L‐Glutamato)(2,2′‐bipyridine)copper(II), and Aqua(L‐glutamato)(1,10‐phenanthroline)copper(II) Trihydrate Complexes.