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Speciation 98: Abstracts
A.Mederos1, S. Domínguez1, E. Chinea1, F. Brito2, S. Midollini3 and A. Vacca4
1 Departamento de Química Inorgánica,
Universidad de La Laguna, Tenerife, Canary Islands, Spain, FAX
34-22-318461;
2 Laboratorio de Equilibrios en Solución,
Escuela de Química, Facultad de Ciencias, Universidad Central
de Venezuela, Caracas, Venezuela;
3 Instituto per lo Studio della Stereochimica ed
Energetica dei Composti di Coordinazione, Via J. Nardi, 39-50132
Firenze, Italy;
4 Dipartimento di Chimica, Universitá di
Firenze, Via Maragliano 77, 50144 Firenze, Italy
E-mail amederos@ull.es
Beryllium is the most toxic non radioactive element in the Periodic Table. Due to its low density, high strength and high thermal conductivity, beryllium is a component of materials indispensable in today's nuclear, aeroespace and nuclear industries. Beryllium(II) inhibits numerous enzymes competitive to magnesium or potassium and noncompetitive in the form of beryllium binding to the enzymes. Therefore, there is a lot of interest in the search for suitable ligands as actidotes for beryllium poisoning.
Two type of ligands have received preference attention in the last years as sequestering agents: 1) ligands with carboxylic groups, and 2) ligands with phosphonic groups. Among the ligands with carboxylic groups, o-phenylenediamine-N,N,N',N'-tetraacetic (o-PhDTA) and 3,4-toluenediamine-N,N,N',N'-tetraacetic acids (3,4-TDTA), ligands derived from aromatic diamines; and nitriloaceticdipropionic (NADP) and nitrilotripropionic (NTP) acids, tetradentate ligands that form six-membered chelate rings1,2. The study of ligands with phosphonic groups shows that these ligands form stronger complexes with beryllium(II) than the corresponding carboxylate ligands. In particular, the ligand methylenediphosphonic acid (MDP) form the very stable complex [Be(MDP)2]4-, with six-membered chelate rings3. The formation of this complex may provide a basis for the sequestration of beryllium at physiological pH.
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