Rare Earth Complexes with Amino Acids

4 Rare Earth Complexes with Amino Acids 

Coordination chemistry of RE(III) with amino acids has been attracting much interest since the early 1970s after the discovery that certain RE(III) ions could be used as probes of calcium ion binding sites in proteins and enzymes [118, 119], Since then, a large amount of work on the solution and structural chemistry of rare earth-amino acid complexes has been published. The solution studies involve all of the rare earth elements and 13 (Gly, Ala, Val, Leu, Phe, Met, Pro, Ser, Tyr, His, Lys, Trp, and Arg) of the 20 standard amino acids, and more than 100 of the RE(III)-amino acid complexes have been structurally characterized. This section will cover the synthetic, structural, and solution chemistry of these complexes. 

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Preparation of Rare Earth Complexes with Amino Acids... 

This chapter will cover the synthetic, structural, and solution chemistry of rare earth complexes with carboxylic acids, polyaminopolycarboxylic acids, and amino acids, with an emphasis on their structural chemistry. As the carboxylate groups play the key roles in the metal-ligand coordination bonding in these complexes, we will start the chapter with the coordination chemistry of rare earth-carboxylic acid complexes, followed by rare earth-polyaminopolycarboxylic acid and rare earth-amino acid coordination chemistry. Owing to length limitations, an exhaustive citation of the large amount of research activities on the subjects is not possible. Instead, only selected examples are detailed to highlight the key features of this chemistry. 

Rare Earth Complexes with Carboxylic Acids, Polyaminopolycarboxylic Acids, and Amino Acids 93... 

Figure 2 Bridging modes observed in dinuclear and polynuclear rare earth carboxylates. (Reproduced with permission from from R. Wang and Z. Zheng, Rare Earth Complexes with Carboxylic Acids, Polyaminopolycarboxyhc Acids and Amino Acids in Chim-Hui Huang, Rare Earth Coordination Chemistry Fundamentals and Applications. John Whey Sons (Asia) Pte Ltd, 2010.)...

Trivalent rare earth cations form complexes with a series of hydroxycarboj lic acids and amino acids in aqueous solutions, some of which are listed in fig. 8. Earlier studies of Katzin (1968, 1969) revealed that these biological substrates effectively act as bidentate ligands toward the rare earth cations. Rare earth complexes with multidentate chelators were recently applied as receptors for zwitterionic amino acids of biological and artificial interests. Aime et al. (2001a) characterized the complexation behaviors of zwitterionic amino acids with oc-... 

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