Study of the Complexes of Neodymium (Ⅲ) with Indole-3-Carboxylic Acids and 1,10-phenanthroline by XPS

The complexes of indole-3-carboxylic acids with Nd（Ⅲ） ions have been characterized by XPS.All of the indole-3-carboxylic acids molecules are coordinating to Nd（Ⅲ） in a bidentate fashion through carboxylic oxygen atoms.The chemical composition of binary complexes determined by XPS and elemental analysis are,NdL₃·nH₂O （L=IAA,IPA,IBA）.When the N-containing heteroatomatic ligand,1,10-phenanthroline（Phen）,was added,the coordination modes of IAA,IPA and IBA with Nd（Ⅲ） are significantly changed.It is found that some of the three IAA （or IPA,IBA） molecules are coordinsting to Nd（Ⅲ） in a monodentate fashion throgh carboxylic oxygen atoms,and the others are coordinating to Nd（Ⅲ） in a bidentate fashion through the carboxylic oxygen atoms.The nitrogen atom in the indole ring has not interacted with Nd（Ⅲ） at all,but the two nitrogen atoms in 1,10-phenanthroline are coordinating to Nd（Ⅲ） to form a five-number ring.The chemical composition of these ternary complexes determined by XPS and element alanalysis are,NdL₃·Phen（L=IAA,IPA,IBA）.